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Carrier 48FK Air Conditioner User Manual

1. 30 START UNIT eten 31 34 Quick Test Program 31 OPERATING INFORMATION 34 43 Digital Display RR 34 CODES 0 THROUGH 8 CAPACITY STEPS CODES 20 THROUGH 30 AND 88 OPERATIONAL STATUS CODES 51 THROUGH 87 DIAGNOSTIC INFORMATION Operating Sequence 35 SIZE 034 038 AND 048 088 UNITS e SIZE 044 UNITS e SIZE 104 UNITS Head Pressure Control 36 Supply Fan Control with IGV 38 Supply Fan Control with VFD 38 Modulating Power Exhaust Option or Accessory Except FY JY Units 38 Unit Staging 38 TROUBLESHOOTING 44 57 Checking Display Codes 44 Complete Unit Stoppage 44 Single Circuit Stoppage 44 Restart Procedure 44 Diagnostic 45 CODES 51 52 55 56 COMPRESSOR FAILURE Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations Catalog No 534 716 Book 1 PC 111 Tab 1a 1b Printed in U S A Form 48 50F J 1T Pg 1 4 99 Replaces 48 50D F J 1T CONTENTS cont Page CODES 59 AND 60 LOW PRESSURE SWITCH CODES 63 AND 64 OIL PRESSURE SWITCH CODE 70
2. e e ol ea a 10 ENTHALPY CONTROL DIFFERENTIAL ENTHALPY Variable Frequency Drive VFD 12 Temperature Reset 12 CONTROLS INSTALLATION 13 25 Control Wiring 13 NIGHT SETBACK THERMOSTAT SPACE TEMPERATURE RESET ACCESSORY 50DJ900021 Space Temperature Reset 13 INSTALLATION CONFIGURATION OPERATING SEQUENCE Demand Limit 18 SINGLE STEP DEMAND LIMIT TWO STEP DEMAND LIMIT INSTALLATION CONFIGURATION OPERATING SEQUENCE Control From Remote Building Management System BMS 19 OCCUPIED UNOCCUPIED Smoke Control Modes 21 FIRE SHUTDOWN MODE PRESSURIZATION MODE EVACUATION MODE SMOKE PURGE MODE INSTALLATION CONFIGURATION OPERATING SEQUENCE Air Pressure Tubing 23 INLET GUIDE VANES e VARIABLE FREQUENCY DRIVE e MODULATING POWER EXHAUST STARTUP 2225 ct tous eet uS mE 25 30 Initial CHECK ea AAS ad oe omes 25 Configuration Header 26 DIP 26 Adjusting Set Points 27 Potentiometers 27 Supply Fan Control with IGV Option 28 Supply Fan Control with VFD Option 28 Modulating Power Exhaust Option or Accessory
3. CL 1 lil START UP CHECK EVAPORATOR FAN SPEED AND RECORD CHECK CONDENSER FAN SPEED AND RECORD AFTER AT LEAST 10 MINUTES RUNNING TIME RECORD THE FOLLOWING MEASUREMENTS COMP 1 OIL PRESSURE COMP 2 COMP 1 COMP B2 SUCTION PRESSURE SUCTION LINE TEMP DISCHARGE PRESSURE DISCHARGE LINE TEMP ENTERING CONDENSER AIR TEMP LEAVING CONDENSER AIR TEMP EVAP ENTERING AIR DB TEMP EVAP ENTERING AIR WB TEMP EVAP LEAVING AIR DB TEMP EVAP LEAVING AIR WB TEMP COMPRESSOR AMPS L1 COMPRESSOR AMPS 12 COMPRESSOR AMPS L3 ELECTRICAL SUPPLY FAN AMPS ELECTRIC HEAT AMPS LI L2 TEMPERATURES OUTDOOR AIR TEMPERATURE RETURN AIR TEMPERATURE COOLING SUPPLY AIR F PRESSURES GAS INLET PRESSURE IN WG GAS MANIFOLD PRESSURE STAGE NO 1 REFRIGERANT SUCTION CIRCUIT NO 1 REFRIGERANT DISCHARGE CIRCUIT NO 1 GENERAL IV NOTES Copyright 1999 Carrier Corporation EXHAUST FAN AMPS L3 DB Dry Bulb F DB F WB Wet Bulb IN WG PSIG PSIG STAGE NO 2 CIRCUIT NO 2 CIRCUIT NO 2 IN WG PSIG PSIG VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS IN UNIT INSTALLATION INSTRUCTIONS ECONOMIZER MINIMUM VENT SETTING TO JOB REQUIREMENTS Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations Catalog No 534 716 Printed in U S A Book 1 1 PC 111 Tab 1a 1b Form
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5. 5 If voltage is still incorrect replace processor board 6 Turn power to ON position J7 9 J9 TP18 TP10 TPIS TP14 wu zuo LEGEND J Pin Terminal Strip TP Test Pin Fig 48 Processor Board Test Points P N REV S N C 32 0160 793 1 55 15 793 1 w 2 m x K1 K2 K3 LEGEND CR Control Relay J Pin Terminal Strip Relay Fig 49 Relay Board Test Points Step 5 Check Relay Board Outputs from the Processor Board This step involves checking the output signals from relays K1 K3 on the relay board 1 Turn power to OFF position 2 Connect negative test probe to TP19 meter still set to dc 3 Turn switch to ON position and enter Quick Test mode 4 Connect positive test probe to terminal 14 on pin termi nal connector J9 and check voltage from TP19 to ter minal 14 on pin terminal connector J9 5 If not 12 1 vdc replace processor board 6 Turn switch to OFF position 7 Remove negative test probe from TP19 Connect positive test probe to TP15 8 Turn switch to ON position and go into Quick Test mode 9 Place negative lead on terminals shown in Table 23 and check voltage between TP15 and terminals shown in Table 23 on pin terminal connector J9 See Fig 50 for J9 details 2 4 6 8 10 12 14 J9 ENS Bm e
6. 1 3 5 7 9 11 13 Fig 50 Relay Board Pin Terminal Connector J9 Table 23 Voltage Reading QUICK TEST 49 NUMBERS STEP NO 112 3 456 7 8 9 10 11 12 13 0 1 2 3 01000010 0 0 01 of 0 12 2 4 0 of of Oj 12 0 0 of 0 12 2 5 01000010 0 0 0 of 0 12 2 6 01000010 0 oji2 0 0 12 2 7 01000010 0 0 0 12 0 12 2 8 01000010 0 01 0 0 12 12 2 9 12 0 0 0 0 010101 0 12 3 0 01210010 0 0 0 of of 0 12 3 1 0 01121010 0 0 0 of of 0 12 3 2 0101 0 0112 0 0 0 01 of 0 12 3 3 of of 0 0 0 12 0 0 oj 0 0 12 NOTES 1 Pins shown in boldface type will only be energized for 10 sec onds All other pins will be energized continuously while at the proper quick test step The control will only stay in the Quick Test routine for 10 minutes unless the display button is pressed 2 Acceptable range for the voltage reading Ov Oto4v 12 v 11 to 13 v 3 1 any of these voltages are not measured replace the processor oard Step 6 Display Board Connection Checkout 1 Turn power to OFF position 2 Disconnect the ribbon cable 3 Connect negative lead of meter to TP18 4 Turn power to ON position and go into Quick Test mode 5 Place the other lead on terminals shown in table below and check voltage at pin terminals on pin terminal con nector J10 see Fig 51 for pin terminal connector J10 details PIN TERMINAL VOLTAGE DC 17 5 18 5 20 2 5 22 2 5 24 5 Vo
7. informs the processor of the status of the compressor safe ties energizes the compressor contactor coil and deener gizes the crankcase heaters A fault will be detected by the processor if the control relay opens during operation or start up The processor will lock the compressor or the circuit off by deenergizing the appropriate relay s on the relay board and energizing an alarm signal Accessory Board The accessory board is standard factory supplied in the VAV rooftop units See Fig 15 This board is located in the control box of each unit Each board has a prewired connector supplied with it to connect directly to the processor board It has 3 potentiometers P3 P5 and P6 P3 RESET LIMIT The processor board is programmed for occupied space temperature reset In order for reset to work the accessory temperature reset board must be used Potentiometer P3 is the maximum set point temperature to which the supply air can be reset P5 ECONOMIZER MINIMUM POSITION This po tentiometer controls the set point for the minimum position of the economizer P6 MORNING WARM UP TEMPERATURE This po tentiometer controls the morning warm up temperature set point Single Step Demand Limit The single step de mand limit provides a means to limit the capacity of the VAV unit using an external switch Single step demand limit will limit the compressor displacement based on the ratio of the wiper arm to the full
8. 9 SENSOR AVERAGING APPLICATION Fig 26 Space Temperature Sensor Averaging Demand Limit The demand limit function provides a means to limit the cooling capacity of the VAV unit using an external discrete switch function When enabled by the closure of the external switch the control will limit the avail able compressor staging capacity according to user set points established at demand limit potentiometer s The unit controls support two types of demand limit single step and 2 step control SINGLE STEP DEMAND LIMIT This function will limit the total compressor staging based on the ratio of the set point potentiometer s wiper arm position to the full scale resis tance of the potentiometer The exact percentage of capacity reduction differs depending on the number of capacity steps A field supplied potentiometer and control switch are re quired for this function See installation section for speci fication on potentiometer and field wiring TWO STEP DEMAND LIMIT Two step demand limit is provided with the installation of the accessory Demand Limit 18 Control Module kit plus installation of 2 field supplied con trol switches SPST NO each This accessory control pro vides for a first step reduction of 5096 to 100 of the maxi mum compressor staging the second step provides for reduction between 0 and 49 The exact percentage of capacity re duction differs depending on the number of capacity steps When
9. DPS then opens its control contacts and PEDM maintains current position When space demand moves PEDM to 90 of full open position auxiliary switch PEDMS closes energizing fan con tactor PEC2 Fan motor no 2 starts and runs Increased ex haust airflow will lower space pressure causing DPS to drive PEDM back towards its closed position until the set point is achieved If space pressure decreases until PEDM position is re duced to 1046 of open position PEDMS will open deener gizing fan contactor PEC2 and shutting off fan no 2 Unit Staging Compressor loading and unloading se quences are shown in Table 19 a 5 5 3 zd 28 E ae Eve ate 858 8584 PELE 532 5855 ge FER 2er 2 po a 4 2 8 a a VIEW C C VIEW B B SCALE 1 6 N ee S QS Fig 44 Modulating Power Exhaust Component Locations Sizes 034 048 39 VIEW C C SCALE 1 3 Fig 45 Modulating Power Exhaust Component Locations Sizes 054 104 ECONOMIZER SECTION SIDE PANEL Yi 5 4 P ACCESS DOOR amp FRAME 55 BOTH SIDES BAROMETRIC RELIEF HOODS ASSEMBLIES MODULATING POW
10. Faulty Wiring If wiring is incorrect between potentiom eter and processor board or display board a failure will result Potentiometer Failure If potentiometer is shorted or open a failure will result CODE 83 ECONOMIZER FEEDBACK POTENTIOM ETER FAILURE If potentiometer on economizer motor P2 fails control will use a default value of 096 and econo mizer outdoor air dampers will close The failure will en ergize alarm light and cause an error code of 83 to be dis played when display button is pushed This potentiometer is a 5 to 15 Kohm potentiometer If potentiometer returns to normal control will automatically reset If a failure occurs one of the following is the probable cause Faulty Wiring If the wiring between processor board and potentiometer is wrong this will cause a failure Potentiometer Failure If potentiometer is shorted or open this will cause a failure Economizer Damper Stuck The control has been pro grammed to indicate an error if potentiometer travel is less than 1096 of the full range This would happen if dampers or damper linkage were hung up and could not move properly CODE 84 RESET LIMIT POTENTIOMETER FAILURE This code is applicable only if reset is being used If reset is being used DIP switch 2 must be in the ON position This potentiometer P3 is located on the accessory board If po tentiometer setting is less than 0 F or greater than 80 F alarm light will b
11. ILLEGAL UNIT CONFIGURATION CODES 71 TO 76 THERMISTOR RESISTOR FAILURE CODE 81 RESET THERMISTOR OR POTENTIOMETER FAILURE CODE 82 LEAVING AIR TEMPERATURE SET POINT POTENTIOMETER FAILURE CODE 83 ECONOMIZER FEEDBACK POTENTIOMETER FAILURE CODE 84 RESET LIMIT POTENTIOMETER FAILURE CODE 85 DEMAND LIMIT POTENTIOMETER P4 FAILURE CODE 86 MINIMUM POSITION ECONOMIZER POTENTIOMETER FAILURE CODE 87 WARM UP TEMPERATURE SET POINT FAILURE Thermistor Troubleshooting 47 Electronic Controls Checkout 47 PROCESSOR BOARD CHECKOUT RELAY BOARD TROUBLESHOOTING DISPLAY BOARD CHECKOUT ACCESSORY BOARD CHECKOUT TWO STEP DEMAND LIMIT CONTROL MODULE DLCM TROUBLESHOOTING Enthalpy Sensor Checkout 51 Economizer Motor 52 Variable Frequency Drive 52 STANDARD TRANSDUCER CONTROL EXTERNAL SIGNAL CONTROL SUPPLY FAN MOTOR OVERLOAD PROTECTION VFD Operation 54 VFD Operational Status 54 Restoring Factory VFD Defaults 54 Unit Wiring RR RR 54 START UP CHECKLIST CL 1 CL 2 SAFETY CONSIDERATIONS Installing starting up and servicing this equipment can be hazardous due to system pressures electrical compo nents and equipment location roof elevated structures etc Only trained qualified installers and service mechanics s
12. Potentiometer OK Accessory Reset Limit 0 Potentiometer Faulty or Option not used Potentiometer P3 1 Potentiometer OK Accessory Demand Limit 0 Potentiometer Faulty or Option not used Potentiometer P4 N xa Minimum Position Economizer Potentiometer P5 1 Potentiometer OK Warm Up Set Point 0 Potentiometer Faulty or Option not used Potentiometer P6 Potentiometer P2 is not listed since it is not part of the quick test If on unit start up a Code 83 is displayed check potentiometer P2 1 Potentiometer OK N 0 Potentiometer Faulty or Option not used Table 17 Quick Test Output Relay Check STEP NO a Energize Stage 1 Condenser Fan s K11 e 6 6 LEGEND CR Control Relay K9 fan relay will remain on for duration of quick test TCompressor will be energized for 10 seconds Zero indicates open CR 1 indicates closed CR 33 Table 18 Sensor Resistance Values TEMP RESISTANCE TEMP RESISTANCE TEMP RESISTANCE F Ohms F Ohms F Ohms 45 60 362 640 1 020 55 297 140 929 50 245 245 844 45 202 841 768 40 168 250 699 35 139 960 640 30 116 820 585 25 98 420 535 20 82 665 490 15 69 685 449 10 58 915 414 5 50 284 380 0 42 765 350 5 36 475 323 10 31 216 299 15 26 786 276 20 23 164 255 25 19 978 236 30 17 276 219 35 14 980 40 13 085 3 Quick Test Steps
13. WINDING CLOSE A BRAKE WINDING RED YEL AUX SWITCH LEGEND CCW Counterclockwise Cw Clockwise Fig 52 Damper Motor Connection Diagram 52 Variable Frequency Drive A WARNING Factory installed optional VFD is located near the sup ply fan and motor During any service work or pro gramming at the operation of the fan and motor is not desirable Either disable the supply fan or install an accessory VFD remote display NOTE VFDs part no TOS VERT 130 E3 are specially modified for use on Carrier equipment Some specifications and control configuration defaults for Carrier applications will differ from the VFD manufacturer manual included in the packet See Table 29 for listing of Carrier specific de fault values STANDARD TRANSDUCER CONTROL The moni tors and controls duct pressure DP via a differential pres sure transducer The pressure transducer is located in the auxiliary control box 034 048 units or in the supply fan compartment see Fig 34 The pressure transducer s low pressure reference port is connected to the outside of the unit cabinet by a factory installed tubing section The pressure transducer s high pressure reference point must be field connected to the duct pressure pick up field supplied and installed in the supply duct The DP transducer monitors the static pressure in the sup ply duct and provides a
14. dicate an error Relay Board Failure If small 24 v relay on the relay board fails microprocessor will detect this through feedback con tacts and indicate an error Processor Board Failure If hardware that monitors feed back switch fails and processor board fails to energize the relay board relay to ON position an error may be indicated The control does not detect compressor circuit breaker failures Wiring Problem A wiring error or a loose wire may cause the feedback circuit to be broken Table 22 Diagnostic Codes DISPLAY DESCRIPTION OF FAILURE ACTION TAKEN RESET BY CONTROL METHOD Circuit 1 shut off Manual Circuit 2 shut off Manual Compressor 3 shut off Manual Compressor 4 shut off Manual 51 Compressor 1 failure 55 Compressor 2 failure 52 Compressor 3 failure 56 Compressor 4 failure PROBABLE CAUSE High pressure switch or high dis charge gas thermostat switch trip compressor ground current gt 2 5 amp or compressor board relay on when it is not supposed to be on Wiring error between electronic control and compres sor protection module 59 Loss of charge circuit 1 Circuit 1 shut off Manual This indicates either a low refrig 60 Loss of charge circuit 2 Circuit 2 shut off Manual erant charge or a loss of charge switch failure 63 Low oil pressure circuit 1 Circuit 1 shut off Manual Not used Check jumper on pro 64 Low oil pressure circuit 2 Circuit 2 shut off Manual cessor board
15. nates all unit operation cooling heating supply fan and power exhaust This mode prevents recirculation of contaminated air back into the space or the admission into the space of unsuitable outside air PRESSURIZATION MODE Pressurization mode is in tended to keep smoke out of a zone Factory installed op tional economizer is required for this function Pressuriza tion is accomplished by opening the economizer option e running the supply fan optional inlet guide vanes open or optional variable frequency drive at normal duct static pressure set point closing the power exhaust dampers if installed as option or accessory shutting off the power exhaust fans if installed as option Or accessory This allows the space to be overpressurized relative to ad jacent zones and prevents or slows entry of smoke into this space from adjacent zones 21 034 048 TB3 054 104 TB4 rssb cEnp R CONTROL L 12 ye a TO 20 MA R 2TO10VDC i SIGNAL 15 sed LEGEND P Manual Potentiometer Fixed Resistor Field Wiring Fig 30 Remote SASP Wiring TB2 TB2 4 5 R WN O RELAYO z LI 7 1 _ E d l Lo SIGNAL TO BMS LEGEND Resistor Factory Installed Factory Wiring Field Wiring Fig 31 External Alarm Indicat
16. 4 to 20 mA signal directly to the VFD Refer to Table 13 for transducer output signal mA for actual duct static pressure The internal logic of the VFD compares this signal representing actual duct pressure to the user configured DP set point The VFD automatically ad justs its output to the supply fan motor to maintain the de sired DP set point When operating with the factory standard DP transducer the internal PID logic of the VFD is enabled EXTERNAL SIGNAL CONTROL If the VFD is to be controlled by an external control system other than the fac tory supplied pressure transducer the internal PID logic func tion of the VFD must be disabled To disable the PID control 1 Disconnect all power to the unit and the VFD 2 Install a jumper across S2 CC see Fig 53 and 54 for VFD terminal board connections 3 Remove factory supplied cable attached to IV and CC 4 Remove other end of the same cable from the pressure sensor 5 Connect field supplied speed reference 4 to 20mA across terminals IV CC 6 Disable the supply fan motor operation 7 Reconnect power to the unit and VFD 8 Reprogram the VFD to accept an external reference in the Utility parameters group Gr Ut set parameter item Fnod no 312 4 9 Enable supply fan motor and return power to the unit SUPPLY FAN MOTOR OVERLOAD PROTECTION The VED provides operating overload protection for the supply fan motor The factory has programmed the VE
17. 83 P N PI REV B 99 SIN B 8 B 5 ES E 4 J3 e POTENTIOMETER A TE CONNECTOR 8 3 geo 3 zi 924 RI a lo eg of RI li TP4 8 3 JE 3 B E 3 9 B 3 8 uo Q Pa 1 0055505509210 6555505509213 SI 2 e R59 32GB500884 1 2400000000 0000 9914 42 JI J4 SWITCH THERMISTOR TRANSFORMER CONNECTOR CONNECTOR CONNECTOR LEGEND EPROM HT204485 1 XX where XX is the current revision DIP Dual In Line Package number EPROM Erasable Programmable Read Only Memory EXV Electronic Expansion Valve A WARNING Do not remove label covering EPROM Removal causes pro gram to be erased NOTE Processor Board is positioned in unit with J3 and J10 con nections at the bottom Fig 1 Processor Board Several temperature inputs are connected to the proces sor There are either 4 or 5 thermistors depending on the field installed accessories which input temperature data into the processor through pin terminal connector J1 See Table and Fig 2 Several status switches are also monitored These switches are connected to the processor at pin terminal connector J2 See Fig 3 and Table 2 Table 1 Pin Terminal Connector J1 Thermistor Inputs In addition to the unit status switch inputs the processor board also accepts inputs from several potentiometers These potentiometers control v
18. Control with IGV In most VAV units the supply fan static pressure is controlled by inlet guide vanes The inlet guide vanes operate independently from the micro processor The supply static pressure is controlled by a dif ferential pressure switch If the unit is equipped with a re turn fan building pressure is controlled by another differential pressure switch For example assume that set point on supply fan differ ential switch is 1 9 in wg If pressure in supply duct goes above 1 9 in wg switch will make to the normally open contact and energize inlet guide vane motor to drive inlet guide vanes to a more closed position thus reducing airflow and lowereing duct pressure Once set point pressure is reached switch will open and deenergize inlet guide vane motor If pressure in supply duct is below 1 9 in wg the switch will make to the normally closed contact and energize inlet guide vane motor to drive inlet guide vane to a more open posi tion increasing airflow and raising duct pressure Once again once desired pressure has been reached switch will open and deenergize inlet guide vane motor How far above or below the set point setting the switch goes before energizing de pends on setting of null span null span is pressure change that can be made without contacts opening or closing If null span is at maximum position pressure will vary from 0 17 in wg to 0 31 in wg depending on set point if set point is at minimum set
19. Up 5 Demand On Enable Demand Limit Limit Off Disable Demand Limit Off Off No Unloaders On Off 1 Unloader Off On 2 Unloaders Not Used Off No Significance LEGEND DIP Dual In Line Package Control circuit breaker must be off before changing the setting of the DIP switch TNo economizer And or electric heat 50FK JK units without plenum only SWITCH NO 6 7 Unloaders Adjusting Set Points Set points for unit operation are established via potentiometer settings Set points for Sup ply Fan controls are set at the VFD keypad if installed or at the IGV differential pressure switch DPS1 if IGV op tion installed Set points for modulating power exhaust op tion or accessory are set at the differential pressure switch DPS2 Potentiometers of the set point potentiometers must be set before the unit is started in order for the unit to function properly Each of the potentiometers has a valid range that is used by the control The valid range is defined as the potentiometer s resistance value that the control will not con sider to be in error This is usually between 10 and 9096 of the potentiometer s total resistance The control has been programmed to accept an operational range for the poten tiometer which may not be the same as the valid range 27 Potentiometer inputs and ranges are summarized in Table 9 Information on individual set point potentiometers including function locat
20. VANE DIFFERENTIAL PRESSURE SWITCH Fig 33 Modulating Power Exhaust and Inlet Guide Vane Differential Pressure Switch Sizes 034 048 INLET GUIDE VANE DIFFERENTIAL PRESSURE SWITCH OR DUCT Fig 34 Inlet Guide Vane Differential Pressure Switch and Variable Frequency Drive Duct Pressure Transducer Sizes 054 104 POWER EXHAUST CONTROL BOX FILTER SECTION MODUL ATING POWER EXHAUST DIFFERENTIAL PRESSURE SWITCH Fig 35 Modulating Power Exhaust Differential Pressure Switch Sizes 054 104 25 MODULATING POWER EXHAUST The tubing for the building pressure control achieved via the Modulating Power Exhaust option should sample building pressure in the area near the entrance lobby or other appropriate and sensitive location so that location is controlled as closely to design pressures as possible A differential pressure switch DPS is used to control the actuator on the modulating discharge damper in exhaust fan no 1 The building pressure BP DPS is located in the aux iliary control box of the unit See Fig 33 and 35 Use a nomi nal in plastic tubing For instructions on adjusting BP control set points refer to Start Up Modulating Power Exhaust section in this book START UP Initial Check IMPORTANT Do not attempt to start unit
21. con densing temperature input from either circuit s T3 or T4 thermistor On Size 088 units the first 4 condenser fans energize with the compressors compressor no controls OFM1 and OFM3 and compressor no 2 controls OFM2 and OFM4 The OFM5 and OFM6 are staged by the microprocessor based on condensing temperature input from either circuit s T3 or T4 thermistor Stage 2 Stage 3 Stage 4 Stage 5 Stage 6 SIZE 044 UNITS These units have 2 compressors and 1 unloader on compressor no 1 See Fig 42 for compressor and condenser fan motor locations The unit operating se quence is as follows Stage 1 Relays and are energized Compressor no 1 starts with the unloader energized Com pressor no is running at 2 capacity The crank case heater on compressor no 1 has been deen ergized and the first stage condenser fan has been energized Outdoor condenser fan motor no 1 OFM 1 has started Relay KI is energized Compressor no 1 is fully loaded Relays K1 K3 and 5 are energized Compres sor no 1 is running at 2 capacity and compres sor no 2 is running at full capacity The crankcase heater for compressor no 2 is deenergized The second stage condenser fan has been energized Both OFMI and OFM3 are operating Relays KI and K5 are energized Both compres sors are running fully loaded Size 044 units have one fan that can be controlled by the processor The other 2 are controlled by th
22. demand limit is active the LED display will show code A INSTALLATION Single Step Demand Limit A 3 wire 5 to 20 K ohm po tentiometer must be field supplied and installed A single pole normally open switch is also required field supplied and installed Locate the potentiometer designated P4 and the switch in a suitable location external from the unit or in the unit control box Connect the potentiometer end terminals to terminals 8 and 9 on control terminal block TB3 sizes 034 048 or TB4 sizes 054 104 see Fig 27 Connect the switch terminals to the potentiometer wiper arm terminal and to terminal 10 on TB3 or TB4 To enable demand limit function change DIP switch 5 to position ON Disconnect control power before changing DIP switch positions Reconnect power after all changes have been made Set the potentiometer P4 to desired capacity reduction value Two Step Demand Limit Install the demand limit con trol module DLCM according to the installation instruc tions provided with the accessory Disconnect existing leads at connector J3 on the processor board see instructions and connect the plug from the DLCM harness to connector J3 Connect the field input control power wires from the ex ternal control relays at the terminal strips marked IN1 RTN1 IN2 and RTN2 see Fig 28 and 29 To enable demand limit function change DIP switch 5 to position ON Disconnect control power before hanging DIP sw
23. e Be 0 el 0000 13 HS A va 8 8 8 5 a 2 65 3 e PSS l TWM X09 1081409 NO Q31V201 8 AVTIAY 1 1 la pe i TWA L3 NO 8 X08 I0H1N02 Us ES a koman L QuYOB AVISU L 2 N TI THA NUO Fe Q mu nooa 104 ew l o a 1547 N m ng o 52 D o o D au 49 ON __ 11 H3Z1W0NO23 nr a ko 8 M NO 1V3H HOI 7 Tid 235 2540 oo p _ e w da E se um N auyoa Dam LO 5 40553009 M 2 Gon fol l 220 eo 42 MWA 1397 NO XOB D 5 ooo ooo TOULNOI EO i L fed a Kp ao N 3 mcm eoe 1 E a 203 1938 an E o o 2 WOLLOG OL OLNDOH u3lvaH 30405 5241 be 3 AT touni W 9 rg e 0 ESE T
24. is reduced by the amount set on potentiometer P1 When power is supplied to terminal IN2 only or to both IN1 and IN2 the capacity is reduced by the amount set on potentiometer P2 GAS HEAT 48FK JK ONLY HORIZONTAL DISCHARGE 50FY JY ONLY SECTION OR EXTENDED PLENUM SECTION SOFKX FKY JKX JKY FILTER SECTION LIT FE kol GAS SECTION HORIZONTAL SUPPLY SECTION 48FK JK ONLY 50FY JY ONLY AND EXTENDED PLENUM SECTION 50FKX FKY JKX JKY Fig 7 Thermistor T1 Location 48FK JK 50FY JY and 50FKX FKY JKX JKY 034 048 Units FILTER SECTION FAN DISCHARGE SECTION II 4 m nin ELECTRIC HEAT SECTION FAN DISCHARGE ELECTRIC HEAT SECTION Fig 8 Thermistor T1 Location 50FK JK034 048 Units 8 FILTER SECTION GAS HEAT 48FK JK ONLY HORIZONTAL DISCHARGE 50FY JY ONLY SECTION OR EXTENDED PLENUM SECTION SOFKX FKY JKX JKY GAS SECTION HORIZONTAL DISCHARGE SECTION 50FY JY AND EXTENDED 48FK JK PLENUM SECTION 50FKX FKY JKX JKY Fig 9 Thermistor T1 Location 48FK JK 50JY and 50JKX JKY 054 074 Units and 50FKX FKY and 50FY054 104 Units FILTER SECTION EVAPORATOR FAN SECTION ELECTRIC HEAT FAN DISCHARGE ELECTRIC HEAT SECTION Fig 10 Thermistor T1 Location 50FK JKO54 074 Units 9 2 STANDARD BAG FILTE
25. no 2 and no 4 are running at full capacity The crankcase heater on compressor no 4 is deener gized Fans OFM1 OFM2 OFM3 and OFM4 are operating Relays K1 K5 and K6 are energized Compres sors no 1 no 2 and no 4 are running fully loaded Relays K1 K2 K3 K5 and K6 are energized Compressor no 1 runs at 75 capacity and com pressors no 2 no 3 and no 4 are running at full capacity Fans OFM1 OFM2 OFM3 and 4 are operating Crankcase heater for compressor no 3 is deenergized Relays K1 K2 K5 and K6 are energized Com pressors no 1 no 2 no 3 and no 4 are running fully loaded On Size 104 units the first 4 condenser fans energize with the compressors circuit no 1 compressors control OFMI and OFM3 and circuit no 2 compressors control OFM2 and OFMA The 5 and OFM6 are staged by the micro processor based on condensing temperature input from either circuit s T3 or T4 thermistor Stage 5 Stage 6 Stage 7 Stage 8 Head Pressure Control units have as standard a basic head pressure control function which allows the units to operate in cooling down to 45 F If cooling is required at outdoor ambient temperatures lower than 45 F refer to ac cessory head pressure control literature for details Head pressure control is handled by the processor The processor attempts to maintain the head pressure by cycling the condenser fan motors No condenser fans will be run ning without
26. scale resistance The exact percentage of capacity reduction differs depending on the number of ca pacity steps A 3 wire 5 to 20 Kohm field supplied potentiometer P4 is required for this option The potentiometer should be wired to the processor J3 connections In order to control the de mand limit the wiper arm of the potentiometer should be switched open and closed based on the demand limit requirement The control switch is also field supplied and installed If the wiper arm wire is open all capacity stages can be used When the wiper arm wire is closed the capacity is reduced by the amount set on potentiometer P4 Demand Limit Control Module DLCM The DLCM provides a 2 step demand limit control using an ex ternal switch The first step is between 50 and 100 of the maximum compressor displacement See Fig 16 The sec ond step is between 0 and 49 of the maximum compres sor displacement The exact percentage differs depending on the number of capacity steps Two adjustable potentiometers are used to set the 2 de mand limit points Potentiometer P1 is used to set a demand limit between 50 and 100 of the unit capacity Potenti ometer P2 is used to set a demand limit between 0 and 49 of unit capacity If no power is supplied to the demand limit control mod ule all capacity stages can be used When power is supplied to terminal IN1 only the first step of the demand limit con trol is energized and the capacity
27. 0 for 8 NotUsed m Significance factory settings See Table 11 for purpose for each jumper Table 10 Configuration Header and VAY Variable Air Vole O DIP Switch Factory Settings Broken Jumper open Unbroken Jumper closed circuit UNIT SIZE UNIT SIZE DIP Switches The DIP switches configure the unit END 048 088 an yon for several factory installed options and field installed ac Switch cessories plus factory unloaders The DIP switches are lo Position Position Position Position Position Position cated under a plastic enclosure which must be removed for ser BS 0 NET access See Fig 1 The switches can be field adjusted Switches must only be adjusted when control power is deenergized EE e esee Ix won See Table 12 for DIP switch purposes and Table 10 for fac On Off On Off On Off E tory settings of the switch positions 0 oft j Om jn CAUTION ff ff isconnect control power before changin e settings D t control p bef hanging the setting LEGEND of the DIP switches To disconnect control power open the control circuit breaker DIP Dual In Line Package a Broken Jumper open circuit Unbroken Jumper closed circuit Depending on factory installed options or field installed access
28. 2 4 3 3 Output Relay Check These quick test steps allow microprocessor to check output signals from relay boards in unit control system In ad dition operation of all the condenser fans compres sors and economizer if equipped are checked at each step Normal display for Steps 2 4 through 2 8 is 1 In Steps 2 9 through 3 2 each compressor and unloader is started and allowed to run for approximately 10 seconds At start up a 0 will appear on the display followed by a 1 Steps 2 9 and 3 2 in a few seconds Steps 3 0 and 3 1 will always be 0 since there are unloaders and Step 3 3 will always be zero since it is not used At end of the 10 second time period a 0 will return to the display board indicating that test step has been success fully completed Steps 2 9 and 3 2 The 1 indicates that was tested Fan and compressor operating sequence for quick test Steps 2 4 through 3 3 are shown in Table 17 If the quick test steps do not operate as described above a defect exists in one or more of the following relay being tested electronic control or unit wiring Determine problem and correct OPERATING INFORMATION Digital Display The VAV control system uses a 2 digit LED display located on the display board to display opera tional information and diagnostic codes CODES 0 THROUGH 8 CAPACITY STEPS These codes indicate the number of cooling stages active at the time the display button is pressed T
29. 48 50F J 1T Pg CL 2 4 99 Replaces 48 50D F J 1T CUT ALONG DOTTED LINE CUT ALONG DOTTED LINE
30. 48FK JK034 074 SOFK FY JK JY034 104 Variable Air Volume Rooftop Units Controls Operation and Troubleshooting CONTENTS Page Page SAFETY CONSIDERATIONS 2 NIGHT SETBACK CONTROL GENERAL 2 13 e UNIT SUPPLY AIR SET POINT ADJUSTMENT 1 OR STAGE Control System 2 e SUPPLY DUCT PRESSURE SET POINT ADJUSTMENT Processor Board 2 EXTERNAL ALARM SIGNAL e REMOTE ECONOMIZER CONTROL PI SUPPLY AIR SET POINT P2 ECONOMIZER POSITION P3 RESET LIMIT P4 DEMAND LIMIT P5 ECONOMIZER MINIMUM POSITION P6 WARM UP SET POINT P7 SASP RESET TEMPERATURE PROCESSOR BOARD OUTPUTS CONFIGURATION HEADER AND DIP SWITCH ASSEMBLY Relay Board 5 Display 5 Thermistors 5 e TI SUPPLY AIR TEMPERATURE THERMISTOR T2 RETURN AIR TEMPERATURE THERMISTOR T3 SATURATED CONDENSING TEMPERATURE CIRCUIT 1 T4 SATURATED CONDENSING TEMPERATURE CIRCUIT 2 T10 RESET TEMPERATURE Compressor Operation 7 e CONTROL RELAY CR Accessory Board 7 e P3 RESET LIMIT PS ECONOMIZER MINIMUM POSITION MORNING WARM UP TEMPERATURE Single Step Demand Unit 7 Demand Limit Control Module DLCM 7
31. 5 0 5229 1 2 207 Potentiometer Reset limit set point maximum tem 76 0 5100 8 2177 perature value for modified supply air set point Maximum 77 0 4976 0 2 147 of 70 F minimum 40 F Set between leaving air set point 78 0 4854 8 2 117 P1 and 70 F maximum range permitted by control 79 0 4736 9 2 088 OPERATING SEQUENCE If space temperature is above 80 0 4622 4 2 058 reset set point T10 gt P7 reset will occur If space temperature is equal to or less that reset set point T10 P7 the LED will display 20 and reset will begin 17 SIZES 034 048 TB3 en TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SIZES 054 104 TB4 B B SENSOR 1 SENSOR 2 RED BLK eo n BLK SSS SENSOR 3 SENSOR 4 SPACE TEMPERATURE RESET 4 SENSOR AVERAGING APPLICATION SIZES 034 048 TB3 RED D 2 4 2 BLK BLK oo TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SENSOR 1 SENSOR 2 SENSOR 3 xI 18 SIZES 054 104 en qu TB4 LI RED RED us Tg LA SENSOR4 SENSOR 5 SENSOR 6 a NOTE Sensor part number is HH79NZ014 zl m LI RED RED be eq 72 rire See a Sees ee L__ OR SENSOR 7 SENSOR 8 SENSOR 9 SPACE TEMPERATURE RESET
32. 70 Illegal unit configuration Unit will not start Configuration error see Note 1 71 Supply air thermistor failure 72 Return air thermistor failure 75 Circuit 1 saturated condensing thermistor 76 Circuit 2 saturated condensing thermistor 81 Reset temperature thermistor failure 82 Leaving air set point potentiometer failure 83 Economizer potentiometer failure 84 Reset limit set point potentiometer failure 85 Demand limit potentiometer failure 86 Minimum economizer potentiometer failure 87 Warm up set point potentiometer failure NOTES Unit shut off Use default value Unit shut off Stop reset Use default value Close economizer Stop reset Stop demand limit Close economizer Use default value Thermistor or resistor failure wir ing error or thermistor or resistor not connected to the processor board Unit shut off Potentiometer improperly con nected potentiometer setting out of range potentiometer failure or wiring error 1 Illegal unit configuration caused by missing programmable header or both unloader DIP switches on ason All auto reset failures that cause the unit to stop will restart when the error has been corrected All manual reset errors must be reset by turning the control switch off and then back on Valid resistance range for the thermistors is 363 000 to 585 ohms Codes 53 54 57 58 61 62 65 69 73 74 and 77 80 are not used on these units CODES 59 AND 60 LOW PRESSURE SWI
33. 81 6 ON 10 100 42 Table 19 Compressor Loading and Unloading Sequences cont SIZE 054 UNITS STAGE Percent Comp 1 Cylinders Capacity 0 or or or or 9 0 1 20 2 ON OFF 40 3 OFF OFF 6 60 5 OFF ON 100 SIZE 064 UNITS STAGE Percent Cylinders Capacity 0 or or OF OF 0 1 7 2 33 3 oN or OF or 1 9 50 4 oN ON ON ON 8 67 5 83 6 100 SIZE 074 078 UNITS POE Lead Circuit Lag Circuit Active Percent Cylinders Capacity 0 or or OF OF 0 0 1 ON ON ON OFF 2 14 3 H ORR A Se 70 43 4 oN ON ON ON 8 7 5 86 6 100 SIZE 088 UNITS STAGE Percent Cylinders Capacity 0 ORE Fe OPP 0 1 16 2 33 3 ON OFF OFF OFF 50 5 83 6 100 SIZE 104 UNITS STAGE Active Percent Cylinders Capacity 0 or or or or 0 0 1 20 2 6 3 3 50 4 60 5 ON ON OFF ON ON 14 70 7 90 8 100 TROUBLESHOOTING By using the display module actual operating conditions of the unit are displayed while it is running The Quick Test function allows proper operation of compressors compres sor unloaders fans and other components to be checked while unit is stopped If an operating fault is detected an alarm is generated and an alarm code s is displayed For checking specific items see Table 20 Checking Display Codes To view the dig
34. CCUPI CR2 a ERN EOR 160 189 PLI 4 HPS1 PLI B BRN TRAN2 gt I 2 oi ox K oar Oem 2 177180 710 OFH4 054 064 d PL3 3 ie 3 GRA e BLU YEL p PL3 1 m PL3 2 Pik OFMS 074 ONLY ee CR2 ora 3 13 u2 PCBI RCB1 RFC1 vi OED BK ED HED BLK ane 14 PL2 4 HPS2 PL2 6 on 26 2 02 v6 02 EL PEM na Rem ee 2 o ax lt man i 80 636 9 23 wH au PCB2 RCB2 PEC2 RFC2 12 OMR lk BKAN GAZ BH DSK 50 a 5 cop ECR 550 veL 42569 A 22 ve A H92 ve 2 RFM2 13 o gt ERN O FOR 554 BLU 36 2 23 8 3 HEB BLU BU m me PV UNITS o out PLIB 1 PLIS 1 i vi ve tom gt BLU DAHD ax ax 1 12 1 IDC PLIB 2 PLIS 2 DU 77 10M2 YEL JE 4 HIGH HEAT ONLY 500 aki 10M3 TB4 CONNECT FOR APPROPRIATE BS w TB4 UNIT VOLTAGE SEE NOIE 1 WU e kk f n CONTROL TE aw DIK T WIRING 181 au wit PLI 2 zi ux ni m um 550 182 WHT TRANS OWOFE SWITCH HIR Ss L ce GRA ax tie PLI4 1 PLIS 1 PL12 1 PLIS 1 TRAN FIELD REMOVE JUMPER 8 ADD NORMALLY CLOSED ALARM RELAY WESE lt RED
35. D overload function to match the factory installed motor motor size and efficiency If the supply fan motor is changed from the origi nal factory selection the overload value may need to be changed by the service person Contact your local Carrier represen tative for assistance in determining the proper overload setting NOTE Variable frequency drive size is matched to factory installed motor size Do not increase motor size without also changing to equivalent VFD size Table 29 Carrier Default Program Parameter Values PARAMETER GROUP DEFAULT VALUE 60 0 Sec 60 0 Sec 60 0 Hz 10 0 He P3 20 SEtP F P3 0 0 Hz Setup 100 60 Hz See Table 31 0 110 OLN 1 5 rr En He Fundamental z it 2 30 2 sec Gr Fb GA 0 Feedback 80 10 10 10 m 60 Hz Frequency Settings 1 054 104 only 0 054 104 only 1 0 Terminal Selection 1t2 13 3 10 Protection uci 3 1 Gr Ut 1 054 104 only Utility 2 m These settings differ from the Toshiba defaults and are required for Carrier applications NOTE To restore original factory settings change tYP to 6 in Setup mode SetP This restores the VFD original factory settings 53 Fig 53 Variable Frequency Drive Terminal Block Size 034 048 Units Fig 54 Variable Frequency Drive Terminal Block Size 054 104 Units VFD Operation When troubleshooting the VFD check first that all required conditions for VFD operation are satisf
36. Differential Pressure Switch EOR Economizer Open Relay HIR Heat Interlock Relay IFC Indoor Fan Contactor IGV Inlet Guide Vane N C Normally Closed N O Normally Open PEC Power Exhaust Contactor PED Power Exhaust Damper OFC Outdoor Fan Contactor VFD Variable Frequency Drive Air Pressure Tubing Before options such as inlet guide vanes IGV variable frequency drive VFD and or modulating power exhaust can operate properly the pneu matic tubing for pressure sensing must be installed Use fire retardent plenum tubing field supplied Tubing size depends on type of control device see Table 8 below Tubing must be run from the appropriate sensing location in the duct or in the building space to the control device location in the unit Table 8 Tubing Size NOMINAL TUBE Inlet Guide Vanes IGV Variable Frequency Drive VFD Modulating Power Exhaust FK FKX JK JKX 36 INLET GUIDE VANES The tubing for the duct pressure DP control option should sample supply duct pressure about 53 of the way out from the unit in the main trunk duct at a location where a constant duct pressure is desired 23 The inlet guide vanes are controlled by a differential pres sure switch DPS On sizes 034 048 the DPS is located in the auxiliary control box at the economizer end of the unit see Fig 33 On sizes 054 104 the DPS is located in the supply fan section See Fig 34 Use a nomin
37. ER o D 67 BANS CHA NH9 3 k 1 r 2 OG H 62 1 m m 21D V ves chi Lj Kz 2190 100 am EE E h m la Ya e STOUINOD 1140 19 PLAE e o 0 2 a 4 1901 9549 m ou L NO11035 SY9 ka i ee ge orul sa I d p a amp 1 e le auvoa 52299 e TWA 3016 NO Q31V201 X08 1041 02 NO bol 132049 TOULNOJ YIONN 031 907 YOSSFJOUJOUIIH IN3W3ONVHBV 1N3NOdHOO 16 034 048 034 048 Control will automatically adjust leaving air temperature by 054 104 TB4 054 104 TB4 the following formula MSP SP P3 SP 3 x P7 T10 where T 1 MSP Modified Leaving Air Set Point Supply Air Set Point Maximum Supply Air Temperature reset limit Reset Initiation Temperature reset set point Actual Space Temperature Ratio for reset F fixed parameter Table 4 Thermistor Resistance and Voltage Drop Characteristics I AZ 9o gt m WH gt lt 70 P7 rm LI m w gt Q Q I m m I Z j 3 Il NOTES 1 Occ Unocc switch closes when occupied 2 Night setback thermostat closes when in night s
38. ER EXHAUST DIFFERENTIAL PRESSURE SWITCH ACCESS COVER ATMOS 51 v INLET GUIDE VANES DIFFERENTIAL SPEER IC PRESSURE PE Naor PRESSURE SWITCH ACCESS COVER RETURN END PANEL DAMPER MOTOR ACCESS PANEL Fig 46 Modulating Power Exhaust Return End Sheet Metal Skin Detail Sizes 034 048 riss DOOR 4 N ACCESORY POWER EXHAUST how CONTRROL BOX 1 N DIFFERENT IAL PRESSURE SWITCH BRACKET ASSEMBLY BAROMETRIC RELIEF HOODS ASSEMBLY ri RETURN END PANEL TYP BOTH SIDES RETURN END CORNER POST TYP BOTH SIDES Fig 47 Modulating Power Exhaust Return End Sheet Metal Skin Detail Sizes 054 104 41 Table 19 Compressor Loading and Unloading Sequences SIZE 034 UNITS COOLING Lag Circuit STAGE Unloader Unloader Acuve pores 0 0 1 17 2 33 3 50 4 ON ON ON ON 8 67 6 100 SIZE 038 UNITS COOLING Lead Circuit Lag Circuit STAGE Unloader Unloader Active Percent Comp 1 U1 U2 Comp 2 Cylinders Capacity 0 0 1 14 2 28 3 42 4 72 5 86 6 ON 10 100 SIZE 044 UNITS COOLING Lead Circuit Lag Circuit 5 Unioader Active Percent Comp 1 U1 Comp 2 Cylinders Capacity 0 OFF OFF OFF 0 1 ON ON OFF 25 2 ON OFF OFF 50 3 ON 75 4 OFF ON 100 SIZE 048 UNITS COOLING Lead Circuit Lag Circuit STAGE Unloader Unloader Percent 0 0 1 19 2 38 3 58 4 62 5
39. ITCH The modulating power exhaust DPS has a set point range of 0 5 in wg to 0 5 in wg Factory setting is 0 1 in wg To adjust set point turn set point adjusting screw see Fig 39 clockwise to decrease set point and counterclockwise to increase set point This switch also has an adjustable null span The null span is the pressure change that can be made without contacts opening or closing It is adjustable from 0 06 in wg to 0 14 in wg when set point is at minimum position 0 5 in wg and 0 07 in wg to 0 14 in wg when set point is at maximum position 0 5 in wg To adjust null span turn null adjusting screw Fig 39 clockwise to decrease span and counterclockwise to increase span All switches leave factory with null span set at maximum position The smaller the null span the closer the pressure will be maintained to desired set point START UNIT To start unit 1 Close the unit mounted ON OFF switch located in the main control box 2 Close the field supplied and installed timeclock or con trol switch contacts located at Terminals 1 and 2 TB3 for 034 048 TB4 for 054 104 IMPORTANT The field supplied and installed switch or timeclock MUST BE CLOSED to put unit in Occupied mode Unit WILL NOT START until this is accomplished 3 Initialization mode begins see Operating Information sec tion on page 34 for complete description of sequences and display codes 4 Run Quick Test If the display b
40. L16 6 114 6 an m Evo 4 e SINGLE STEP 2 DEMAND LIMIT MT 00 ED 1 TEA accessory RESET L Ss BRN BRN 09 D WHT TRANS PLS 1 l neo nto OD usd I uso mel Tom DL GRA BLK VIO TRANG PLB 2 93 2 KL LOS 1 usd asa VFD RED ZI RED KEN 1 04 gt RED IV ELECTRIC HEAT OPTION I PL4 4 PL20 4 HCI DU PL2O 5 LS 120 6 gt BLK 5 BLK O BLK BLK O Zo BLK 7 E PL4 1 PL20 1 WHT pL20 2 4 2 orn Zorn 1 ORN WTO wr lt p L 3 Ire Fig 55 Typical Wiring Schematic 48FK JK and 5OFK FY JK JY Units 054 074 Shown cont SERVICE TRAINING Packaged Service Training programs are an excellent way to increase your knowledge of the equip ment discussed in this manual including Unit Familiarization Maintenance Installation Overview Operating Sequence A large selection of product theory and skills programs are available using popular video based for mats and materials All include video and or slides plus companion book Classroom Service Training which includes hands on experience with the products in our labs can mean increased confidence that really pays dividends in faster troubleshooting and fewer callbacks Course d
41. Morning Warm Up function This is the temperature at which the morning warm up sequence is terminated and VAV cooling operation begins The valid control range is 0 to 95 F but the control is pro grammed to accept a range of 40 to 80 F If the set point is between 0 and 40 F the control will use a value of 40 F If the set point is between 80 and 95 F the control will use a value of 80 F If the set point is outside the valid range less than 0 F or greater than 95 F an alarm condition will be signaled and a default value of 40 F will be used Supply Fan Control with IGV Option The inlet guide vane option will modulate the supply fan airflow in order to maintain the static pressure in the supply duct The set point for duct static pressure is established at the differ ential pressure switch for the IGV control SIZE 034 048 UNITS The inlet guide vane differential pressure switch is located in the auxiliary control box mounted in the corner under the side air hood that is next to the access door marked FILTER SECTION To gain access to this con trol box remove the auxiliary control box cover When replacing cover be sure to properly secure it in order to prevent water from being drawn into the unit See Fig 36 and 37 SIZE 054 104 UNITS The inlet guide vane differential pressure witch is mounted on an upright located behind the supply fan motor See Fig 36 38 The IGV differential pressure switch has an adjustable
42. None DLCM P1 Demand Limit DLCM Board 50 to 100 None DLCM P2 2 Step DLCM Board 0 to 49 None 5 Minimum Economizer 0 100 Warm U 40 F if 0 F lt P6 lt 40 F OR IF P6 lt 95 F P6 Set Poirt Accessory Board 40 to 80 F OR IF P6 lt 0 80 F if 80 F lt P6 lt 95 Reset P7 Reset Board 40 to 100 F None Optional factory installed economizer is required Potentiometer P2 is not a set point tAccessory two step demand limit module is required which has 2 potentiometers or a 5 to 20 k ohm field supplied potentiometer is required for single step demand limit Accessory temperature reset is required NOTE Potentiometers P1 P6 input data to pin terminal connector J3 Potentiometer P7 inputs data to pin terminal connector J1 Configuration Header The configuration header Table 11 Configuration Header Jumpers is a series of 8 small wires that are broken open circuit or ERE ns unbroken closed circuit in a pattern to indicate several unique NUMBER characteristics of the unit The configuration header is fac Unit Type 5 VAV Rooftop Unit tory set and should not be changed changing the factory set 345 Qty Compressors man 2 Compressors ting may cause the unit to malfunction 6 Expansion Valve XV Before start up visually check the configuration header 7 Power Frequency a 60Hz against the factory setting for the unit size See Table 1
43. On Switch On 0 No Economizer Switch Off 1 Economizer On Switch On 0 No Warm Up Switch Off 1 Warm Up Used Switch On 0 Demand Limit Not Used Switch Off 1 Demand Limit Used Switch On 0 Enthalpy Switch Open 1 Enthalpy Switch Closed 1 Low Pressure Switch Closed 1 Low Pressure Switch Closed No Circuit 1 Oil Pressure Switch No Circuit 2 Oil Pressure Switch 32 CONTROL SWITCH Configuration Header Configuration Header DIP Switch No 6 and 7 Configuration Header DIP Switch No 2 DIP Switch No 3 DIP Switch No 4 DIP Switch No 5 EC Low Pressure Switch 1 Low Pressure Switch 2 None None Table 16 Quick Test Thermistor and Potentiometer Check QUICK NORMAL THERMISTOR OR STEP NO DISPLAY Dever een POTENTIOMETER xx 1 Thermistor OK Supply Air 0 Thermistor Faulty Thermistor T1 e 1 Thermistor OK Return Air L1 5 0 Thermistor Faulty Thermistor T2 1 Thermistor OK Circuit 1 Condenser Thermistor 1 6 0 Thermistor Faulty T3 17 1 Thermistor OK Circuit 2 Condenser Thermistor L 0 Thermistor Faulty T4 1 Thermistor or Potentiometer OK Accessory Space Temperature Thermistor T10 1 8 0 Thermistor or Potentiometer Faulty or 1 Option not used or Accessory Reset Potentiometer P7 1 Potentiometer OK Supply Air Set Point 0 Potentiometer Faulty Potentiometer P1 1
44. RS FILTERS Fig 11 Thermistor T2 Location Size 034 048 Units STANDARD FILTERS BAG FILTERS 054 074 Only Fig 12 Thermistor T2 Location Size 054 104 Units Economizer Economizer control is used to control the outside and return air dampers of the unit to satisfy space cooling demand using all outside air when permitted and to satisfy cooling in conjunction with compressor operation when conditions permit During Occupied periods without cooling demand the outside air dampers will be at the user configured Minimum Damper Position at 5 on accessory board During Unoccupied periods the outside air dampers will be closed The economizer is available as a factory installed option The user can install an accessory differential enthalpy sensor to enhance economizer control Refer to the installation sec tion for field wiring of the sensor 10 CIRCUIT 2 CIRCUIT 1 034 038 tl UNITS CIRCUIT 1 CIRCUIT 2 ul Il 044 048 UNITS Fig 13 Thermistor T3 and T4 Locations Size 034 048 Units ENTHALPY CONTROL Outside air enthalpy control is standard with the factory installed economizer option En thalpy is sensed by a controller located behind the end out side air hood The control can be accessed by removing the upper hood filter See Fig 17 DIFFERENTIAL ENTHALP Y Added efficiencies in econo mizer control can be gained by installing a differe
45. SS AND VERIFY PROPER LEVEL VERIFY THAT CRANKCASE HEATERS HAVE BEEN ENERGIZED FOR 24 HOURS CHECK VOLTAGE IMBALANCE LINE TO LINE VOLTS AB AB BC 3 AVERAGE VOLTAGE MAXIMUM DEVIATION FROM AVERAGE VOLTAGE VOLTAGE IMBALANCE 100 DEVIATION AVERAGE VOLTAGE IF OVER 2 VOLTAGE IMBALANCE DO NOT ATTEMPT TO START SYSTEM CALL LOCAL POWER COMPANY FOR ASSISTANCE PRELIMINARY CHECKLIST ITEMS CONTROL SETTINGS DIP SWITCHES SET TO MATCH INSTALLED ACCESSORIES SUPPLY AIR SET POINT RESET DIP SWITCH NO 4 ON MORNING WARM UP DIP SWITCH NO 4 ON DEMAND LIMIT DIP SWITCH NO 5 ON SUPPLY AIR SET POINT SET BETWEEN 45 AND 70 F ECONOMIZER MINIMUM POSITION P5 SET PER PLANS SUPPLY AIR SET POINT RESET SETTINGS RESET INITIATION TEMPERATURE P7 TYPICALLY 68 TO 72 F RESET LIMIT TEMPERATURE P3 TYPICALLY 60 TO 70 F MORNING WARM UP TEMPERATURE TYPICALLY 50 TO 65 F IGV VFD DUCT PRESSURE SET POINT PER PLANS BUILDING PRESSURE MODULATING POWER EXHAUST SET PER PLANS DEMAND LIMIT SETTINGS PER PLAN SINGLE STEP DEMAND LIMIT P4 SET TYPICALLY 25 TO 50 TWO STEP DEMAND LIMIT DLCM PI SET TYPICALLY 50 TO 75 DLCM P2 SET TYPICALLY 0 TO 25 OCCUPIED UNOCCUPIED SWITCH INSTALLED PER FIG 21 CLOSE TO START UNIT
46. TCH These codes are used to indicate a low pressure switch failure The processor monitors the low pressure switch If the switch opens either by low refrigerant charge circuit failure or wir ing error the circuit is locked off Code 59 indicates a failure of the lead circuit and as a result that circuit will be shut down Code 60 indicates a failure of the lag circuit and as a result that circuit will be shut down These codes will only be displayed when the display button is pressed To reset the circuit the ON OFF switch must be turned to OFF then ON position CODES 63 AND 64 OIL PRESSURE SWITCH These codes are used to indicate an oil pressure switch failure Since the units do not have oil pressure switches these codes are not used The terminals on the processor board must be jum pered together or an error will occur If these errors occur check jumper between J2 1 and J2 2 for a code 63 or be tween J2 3 and J2 4 for a code 64 to be sure jumper is prop erly connected To reset the circuit the ON OFF switch must be turned to OFF and then to ON position CODE 70 ILLEGAL UNIT CONFIGURATION If the unit configuration header is not installed and properly con figured and or if DIP switches are not properly set unit will not start and an error code of 70 will be indicated on display board when display button is pushed Check the header and DIP switch settings CODES 71 TO 76 THERMISTOR RESISTOR FAILURE I
47. a call for mechanical cooling Thermistors T3 and T4 provide the condensing temperature information to the processor These VAV rooftop units have dual refrigera tion circuits and the higher circuit temperature will govern unit operation If the condensing temperature is above 133 F 236 psig a condenser fan stage will be added If the condensing temperature is 78 F 142 psig or less the num ber of condenser fans operating will be decreased After each fan stage the processor will wait one minute for the head pressures to stabilize before changing again unless ther mistor T3 or T4 senses a temperature greater than 125 F 278 psig in which case all condenser fans are started During start up if the outdoor ambient is above 70 F as sensed by thermistor T3 or T4 the first stage processor controlled fans are turned on to prevent excessive discharge pressures COMPRESSOR 2 COMPRESSOR 1 Fig 42 Component Arrangement 034 048 Units 36 054 064 UNITS OFM4 OFM3 074 078 UNITS COMPRESSOR 2 054 088 UNITS OFM6 OFM4 OFM2 5 OFM1 088 104 UNITS COMPRESSOR 1 COMPRESSOR NO 3 COMPRESSOR NO 1 COMPRESSOR NO 1 COMPRESOR NO 3 IS BEHIND IT 104 UNITS Fig 43 Component Arrangement 054 104 Units 37 COMPRESSOR NO 2 COMPRESSOR NO 4 IS BEHIND IT Supply Fan
48. a code of 51 52 56 de pending on compressor when display button is pushed The compressor will be locked off to reset the ON OFF switch must be turned to OFF and then to ON position If lead compressor in a refrigerant circuit is shut down the other compressor in that circuit will also be shut down and locked off Only the error code for the lead compressor will be displayed Code 51 is for compressor 1 and Code 55 is for com pressor 2 Codes 52 and 56 are used for compressors 3 and 4 respectively on size 104 units The microprocessor has also been programmed to indi cate a compressor failure if CR switch is closed when com pressor is not supposed to be on If a failure occurs the following are possible causes High Pressure Switch Open The high pressure switch for each compressor is wired in series with 24 v power that en ergizes CR If high pressure switch opens during operation CR will stop compressor and this will be detected by micro processor through the feedback contacts Internal Thermostat The internal thermostat in each 06D compressor is also wired in series with 24 v power that en ergizes CR If thermostat fails or switch opens during op eration of compressor compressor will shut down and fail ure is detected through feedback contacts size 034 and 038 only CR Failure If CR fails with large relay either open or closed microprocessor will detect this lock compressor off and in
49. al in plastic tubing VARIABLE FREQUENCY DRIVE The tubing for the duct pressure DP control option should sample supply duct pressure about of the way out from the unit in the main trunk duct at a location where a constant duct pressure is desired The duct pressure is sensed by a pressure transducer The pressure transducer output is directed to the VFD On 034 048 units the DP transducer is located in the auxiliary con trol box On 054 104 units the DP transducer 15 located in the supply fan section See Fig 34 Use nominal in plastic tubing DPS HIR TB 054 104 UNITS SW 1 034 048 UNITS SW 1 TB2 Lo 8 ju m Ei 9 s l TB2 SW 2 TB2 TB2 SW 2 TB2 4 REMOVE JUMPER BENGE JUMPER TB3 SW 3 TB3 TB4 SW 3 TB4 kp eee pe ee Hess TB2 SW 4 TB2 TB2 SW 4 TB2 Bro Pose Ho 4 TB2 SW 5 TB2 TB2 SW 5 TB2 42 k o NLe REMOVE JUMPER JUMPER TB2 SW 6 TB2 TB2 SW 6 TB2 9 2 9 41 TB3 SW 9A TB3 TB4 SW 9A TB4 u NUR I e 1 TB3 SW 9B TB3 TB4 SW 9B TB4 LHNO eNe REMOVED M TB3 7 3 KONGre No 42 REMOVED a TB4 7 sw ALL UNITS er WHT REMOVED FROM C DPS al GRA LEGEND Differential Pressure Switch Heat Interlock Relay Switch Terminal Block Fig 32 Smoke Control Wiring 24 MODULATING POWER EXHAUST DIFFERENTIAL PRESSURE SWITCH INLET GUIDE
50. amper p p LEGEND IGV Inlet Guide Vane VAV Variable Air Volume VFD Variable Frequency Drive Power exhaust option accessory required for this mode tApplicable to VAV units with appropriate options CONFIGURATION No set points required for Smoke Con trol modes Modes are activated by energizing all switches appropriate for each Smoke Control mode OPERATING SEQUENCE Fire Shutdown At command from the field switches see Table 5 all unit operation cooling heating supply fan and power exhaust will terminate Pressurization At command from the field switches for Pressurization mode see Table 5 1 Economizer dampers will open 2 The HIR function will energize opening room terminals to full open heating positions 3 Supply fan will run If equipped with IGV control vanes will open If equipped with VFD the VFD will control to duct static set point or best available with all terminals open 4 Power exhaust dampers if equipped will close 5 Power exhaust fans if equipped will turn off Evacuation Atcommand from the field switches for Evacu ation mode see Table 5 1 Supply fan will turn off 2 Economizer dampers will open 3 Exhaust fans will run at maximum capacity 4 Exhaust dampers will open Smoke Purge At command from the field switches for Smoke Purge mode see Table 5 1 Economizer dampers will open 2 The HIR function will energize opening room term
51. arious operational characteristics of the system Inputs are received by the processor through pin terminal connector J3 See Fig 4 All of the potentiometers must be set before the unit is started in order for the unit to function properly See Start Up Potentiometers section on page 28 for information on establishing set points Each of the potentiometers has a valid range that is used by the control The valid range is defined as the potentiometer s resistance value that the control will not consider to be in error This is usually between 10 and CONNECTOR J1 TEMPERATURE UNIT SIZE 2 TERMINAL NO INPUT 034 104 90 of the potentiometer s total resistance The control has 12 Reset Temperature T10 been programmed to accept an operational range for the po tentiometer which may not be the same as the valid range 14 15 Saturated Condensing T4 7 Temp Circuit 2 Saturated Condensing 16 17 Temp Circuit 1 T3 18 19 Return Air Temperature T2 20 21 Supply Air Temperature T1 LEGEND T Thermistor If equipped with accessory temperature reset package NOTE Terminal numbers 3 13 are not used on these units J1 THERMISTOR CONNECTOR e T3 T4 ACCESSORY RESET PACKAGE nn an AAA aes eo M M me LEGEND Thermistor Field Wiring Accessory Fig 2 Pin Terminal Connector J1 Thermistor Inputs Table 2 Pin Terminal Connector J2 Status S
52. at is used to set space tem perature at which reset starts Mount reset board in unit control box or other convenient place Wire thermistor in se ries with P7 and connect to terminals 12 and 15 on terminal block 3 sizes 034 048 or terminal block 4 sizes 054 104 in unit control box If there is a long run to conditioned space it is necessary to splice additional wire to thermistor The reset board has 2 pressure connectors for field wiring See Fig 25 Space Temperature Reset INSTALLATION Install the accessory temperature reset package in accordance with instructions provided with the accessory kit Mount the reset board in the unit control box or other suitable location per instructions Locate the thermistor T10 in a suitable location in the oc cupied space per instructions Wire T10 to the reset board and to the unit control ter minal block per Fig 25 Wire the other terminal on the reset board to the unit control terminal block per Fig 25 If multiple sensors are required to average the space tem perature see Fig 26 Use only Carrier Part Number HH79NZ014 sensor in arrangements of 4 or 9 sensors with total wiring not to exceed 1000 ft To enable reset function change DIP dual in line pack age switch 2 to position ON Disconnect control power be fore changing DIP switch positions reconnect power after all changes have been made CONFIGURATION Set points for reset operation are es tablished a
53. ated and suitable for 115 vac pilot duty operation For Single Step Demand Limit emulate function of switch SW with contact closure controlled by the BMS Set poten tiometer P4 manually at the unit control box Alternatively potentiometer P4 might also be emulated by a variable re sistance transducer with the BMS now able to adjust the amount of demand limit For 2 Step Demand Limit install the accessory Demand Limit Control Module DLCM according the instructions on page 18 Replace switch functions Switch 1 and Switch 2 with contact closures controlled by the BMS see Fig 29 Follow unit control configuration instructions in the De mand Limit section on page 18 SUPPLY DUCT PRESSURE SET POINT ADJUSTMENT Supply duct pressure set point adjustment from a remote BMS is possible when the unit has been equipped with a factory option VED variable frequency drive There are two methods available Direct 4 to 20 mA signal DDC direct to the Direct 4 to 20 mA Signal During normal unit operation the factory installed VFD receives a 4 to 20 mA signal from the Duct Pressure DP transducer which indicates current supply duct pressure The then determines the appro priate fan speed using its internal PID logic feature and adjusts its output to the supply fan motor to suit It is pos sible to emulate this 4 to 20 mA control signal by the BMS which will transfer control of the VFD to the BMS NOTE When pr
54. cated in the unit main control box This potentiometer establishes the set point temperature for the Morning Warm Up function When the temperature is reached Morn ing Warm Up is terminated and VAV operation begins DIP switch 4 must be in the ON position if morning warm up heat is to be used P7 SASP SUPPLY AIR SET POINT RESET TEM PERATURE This 10 Kohm potentiometer is used only if the accessory field installed temperature reset package is in stalled This potentiometer determines the temperature at which reset will begin It is located on the accessory temperature reset board DIP switch 2 must be in the ON position to en able SASP reset PROCESSOR BOARD OUTPUTS The processor board also controls outputs through the relay board The relay board plugs into the processor board using a ribbon cable In addition the processor board controls the display board The display board is connected to the processor board by a ribbon cable and has an LED light emitting diode display showing the status of the unit and diagnostic information CONFIGURATION HEADER AND DIP SWITCH ASSEM BLY The processor board is programmed to control a va riety of air conditioning units To tailor the processor to the particular unit being controlled 2 devices are used One is the configuration header and the other is the DIP switch assembly The configuration header part no 30GB660001 is a series of 8 small wires that are broken or unbro
55. cer OMR Outdoor Motor Relay Enering Air Temperature Power Exhaust Circuit Breaker Enthalpy Control PEC Power Exhaust Contactor Economizer Close Relay PEDM Power Exhaust Damper Motor Economizer Open Relay PEM Power Exhaust Motor Equipment P PL Plug Fan Status Switch Return Fan Circuit Breaker Ground RES Resistor Heat Interlock Relay Return Fan Contactror High Pressure Switch RFM Return Fan Motor Heater Relay SCT Saturated Condensing Thermistor Heater TB Terminal Block Induced Draft Contactor TRAN Transformer Induced Draft Motor U Unloader Indoor Evaporator Fan Contactor VFD Variable Frequence Drive Indoor Fan Circuit Breaker Inlet Guide Vanes Inlet Guide Vanes Motor NOTES Field Wiring Factory Wiring 1 Connect TRAN to HD for 460 v units Connect to for 230 v units If 208 230 v units are run with a 208 v power supply connect to f Connect TRAN to BLK lead for 460 v units Connect to ORN lead for 230 v units If 208 230 v units are run with a 208 v power sup ply connect to RED lead Circuit breaker must trip amps are equal to or less than 156 FLA full load amps for CB1 and 2 All others are 140 If any of the original wire furnished must be replaced it must be replaced with type 90 C wire or its equivalent Number s indicates the line location of contacts A bracket over 2 numbers signifies single pole double throw co
56. ded Relays KI K2 K3 and K5 are energized Com pressor no 1 is running at capacity and com pressor no 2 is running at full capacity The crankcase heater for compressor no 2 has been deenergized Relays K1 K3 and K5 are energized Compressor no is running at 2 capacity and compressor no 2 is running at full capacity Relays and 5 are energized Both compres sors are running fully loaded Size 034 and 038 units have 2 condenser fans one of which is controlled by the microprocessor The OFM 1 is energized with compressor no 1 The OFM2 is controlled by the pro cessor and is cycled based on input from circuit thermistor T3 or 4 Size 048 units have one fan that can be controlled by the processor The other 2 are controlled by the compressors The OFMI is energized by compressor no 1 and OFM3 is energized by compressor no 2 The 2 is cycled by the processor based on input from either circuit thermistors T3 and T4 On size 054 064 units the first 2 condenser fans energize with the compressors compressor no 1 controls OFM1 and compressor no 2 controls OFM2 The OFM3 and OFM4 are staged by the microprocessor based on the condensing tem perature input from thermistor T3 or T4 On size 074 078 units the first 3 condenser fans energize with the compressors compressor no 1 controls OFMI and compressor no 2 controls OFM2 and OFM3 The OFM4 and OFMS are staged by the microprocessor based on
57. due to unacceptable outdoor air enthalpy the dampers will return to the minimum position as determined by P5 35 Compressors unloaders and condenser fans will be cycled to maintain a supply air temperature 2 F below the poten tiometer PI set point once the mechanical cooling stages be gin Each unit s cycling is slightly different and is based on the number of compressors and unloaders The operational loading sequence of compressors is as follows During the start up of the lead compressor for each cir cuit the low pressure switch will be bypassed for 120 sec onds to prevent nuisance trips of the low pressure switch After start up a low pressure trip will be ignored for 30 sec onds by the processor SIZE 034 038 AND 048 088 UNITS These units have 2 compressors and 2 unloaders on compressor 1 See Fig 42 and 43 for compressor and condenser fan motor locations The operating sequence is as follows Stage 1 Relays KI K2 and are energized Compressor no 1 starts with both unloaders energized Com pressor no 1 runs at capacity The crankcase heater for this compressor has been deenergized and the first stage of condenser fans have been en ergized Outdoor condenser fan motor no 1 OFMI has started on all units Relays K1 and K3 are energized Compressor no is running with unloader 1 U1 energized The compressor is now operating at capacity Relay KI is energized Compressor no 1 is fully loa
58. e compressors The OFMI is energized by compressor no 1 and OFM3 is energized by compressor no 2 The 2 is cycled by the processor based on input from either circuit thermistors T3 and T4 SIZE 104 UNITS These units have 4 compressors and 1 unloader on compressor no 1 See Fig 43 for compressor and condenser fan motor locations The unit operating se quence is as follows Stage 1 Relays KI and are energized Compressor no starts with unloader energized Compressor no 1 runs at 25 capacity The crankcase heater for this compressor has been deenergized and first stage of condenser fans has been energized Outdoor con denser fan motor no 1 OFM1 and oudoor fan motor no 3 OFM3 have started Relay KI is energized Compressor no 1 is fully loaded Relays KI K3 and K5 are energized Compres sor no runs at 75 capacity and compressor no 2 is running at full capacity The crankcase heater for compressor no 2 is deenergized The first stae of condenser fans on circuit 2 has been energized Fans OFMI OFM2 OFM3 and OFM4 are operating Stage 2 Stage 3 Stage 4 Stage 2 Stage 3 D 1 034 AND 038 UNITS LEGEND OFM Outdoor Condenser Fan Motor 044 AND 048 UNITS Stage 4 Relays KI and K5 are energized Both compres sors no 1 and no 2 are running fully loaded Relays K1 K3 K5 and K5 are energized Com pressor no 1 runs at capacity and compressors
59. e energized a diagnostic code of will be displayed if display button is pushed and reset will be terminated The full scale resistance of potentiometer is 10 Kohms but when installed on the accessory board in par allel with the other 2 potentiometers measured resistance will be 3 3 Kohms This failure will automatically reset once potentiometer returns to normal If a failure occurs one of the following is the probable cause DIP Switch Problem DIP switch 2 is in the ON position and the accessory board is not installed accessory board is standard on these units so it should always be on the unit Incorrect Potentiometer Setting A potentiometer turned fully clockwise or counterclockwise is outside the valid range and will result in a failure Faulty Wiring If the wiring between the potentiometer and the processor board is incorrect a failure will result Potentiometer Failure If potentiometer is shorted or open a failure will occur CODE 85 DEMAND LIMIT POTENTIOMETER P4 FAIL URE Used only if demand limit is being used If demand limit is used DIP switch 5 must be in the ON position Two types of demand limit are available a field supplied and installed single step control consisting of a 10 Kohm 3 wire linear potentiometer and an accessory 2 step control are available from Carrier The single step control has a single potentiometer while 2 step control has 2 potentiometers mounted on the demand l
60. e information on The has been programmed and wired at factory RESET LIMIT for this application No further adjustments except for Duct Static Pressure Set Point should be necessary at start up 1 Factory jumper wire configurations are shown in the Supply Fan Control with VFD Option section on page 28 1 A separate service manual for the factory installed is supplied with each unit Refer to the VFD manual for more F information on the VFD controls Temperature Reset Accessory temperature reset al CONNECTOR 2 3 lows the unit to automatically adjust reset the supply LEGEND air temperature set point to a higher value once most of the ECON Economizer space cooling load has been met When the space conditions MIN Minimum are satisfied the VAV terminals will close to the minimum P Potentiometer position VAV units will sense the decrease in actual supply Variable Air Volume air temperature and the unit controls respond by reducing Fig 15 Accessory Relay Board Standard Factory Supplied J VARIABLE FREQUENCY DRIVE O oo 20 30 ye IN Spalis RTNI S 80 jc AMP MTA 156 PART 640433 4 wele ERMINALS m g 604 4 125 LEGEND Integrated Circuit IN Input P Potentiometer RTN Ret
61. e nec essary constants for proper unit operation and checks the ther mistors and other potentiometers for their values and valid ity After the initialization period the display screen goes blank until the display button is pressed If the display but ton is pressed during the 2 minute initialization period the control goes into the Quick Test mode Temperature Reset If the unit is equipped with the ac cessory temperature reset package and DIP switch 2 is in the ON position the unit will reset the supply air tempera ture to a calculated value when necessary When this con dition is in effect a will appear in the display Demand Limit If the unit is equipped with the accessory demand limit control module or the field supplied single step demand limit potentiometer and DIP switch 5 is in the ON position the unit will limit the capacity stages to a pre determined value When this condition is in effect a will appear in the display Morning Warm Up If the morning warm up heat routine is enabled using DIP switch 4 and conditions of the occu pied space warrant the unit will begin the morning warm up routine When this condition is in effect a 26 will appear in the display Internal Failure If the unit detects an internal fault such as a time measurement failure or detects an incorrect volt age on an input channel a will be displayed and the unit will shut down Quick Test If the display button is p
62. e pressed twice On first press step number is displayed second press initiates required action and appropriate code is displayed NOTE The step number is a numeral followed by a decimal point a 2 digit number has a decimal point after each nu meral The action code number is one or 2 digits with no decimal point s IMPORTANT Once quick test is initiated display but ton must be pressed at least once every 10 minutes for control to remain in quick test mode If button is not pressed within this time control will attempt to start the unit To recheck any step in quick test program control must be recycled by turning unit control switch off for a few sec onds and then turning it back on again Restart quick test program as described above and proceed through quick test steps Press display button twice for each step until step to be rechecked is reached The quick test program is divided into 3 sections as de scribed below and shown in Tables 15 17 1 Quick Test Steps 1 1 3 Unit Configuration and Switch Check The microprocessor in unit control system is programmed by 2 switch assemblies located on processor board Fig 1 The configuration header is factory set and can not be changed in the field The DIP switch assembly con tains 8 microswitches that must be set in accordance with the various options selected by the customer All DIP switches should be checked and set to proper position for options selected pr
63. ed with warm up heat re quire that room terminals be controlled to go fully open when unit goes into the Heating mode Heating interlock relay HIR is provided for this function The relay is located in the unit control box When unit goes into Heating mode interlock relay is energized providing switch closure or opening de pending on how field power source is set up to open the room terminals Field connections for interlock relays are terminals 3 and 4 for normally open contacts and terminals 3 and 7 for normally closed contacts on terminal block 3 sizes 034 048 or terminals block 4 sizes 054 104 See Fig 24 Note that a field supplied power source is required 13 There are no required 115 volt field wiring connections therefore no provisions have been made in the unit for run ning 115 volt wiring If any of the field installed options re quiring 115 volt connections are desired the unit must be modified in the field for 115 volt wiring NIGHT SETBACK THERMOSTAT Wire field supplied thermostat suitable for 24 v circuit between terminals 1 and 2 on terminal block 3 sizes 034 048 or terminal block 4 sizes 054 104 This thermostat is used to bypass the time clock occupied unoccupied switch and is used to operate unit during unoccupied times at more economical temperatures See Fig 23 SPACE TEMPERATURE RESET ACCESSORY 50DJ900021 Consists of a thermistor T10 and a reset board with a potentiometer P7 th
64. escriptions and schedules are in our catalog CALL FOR FREE CATALOG 1 800 962 9212 Packaged Service Training Classroom Service Training Copyright 1999 Carrier Corporation Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations Book 1 1 PC 111 Catalog No 534 716 Printed in U S A Form 48 50F J 1T Pg 58 4 99 Replaces 48 50D F J 1T Tab 1a 1b START UP CHECKLIST MODEL NO SERIAL NO DATE TECHNICIAN l PRE START UP VERIFY THAT UNIT IS LEVEL VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT LOOSEN ALL SHIPPING HOLDDOWN BOLTS AND REMOVE SHIPPING BRACKETS PER INSTRUCTIONS VERIFY THAT COMPRESSOR SUSPENSION SPRINGS HAVE BEEN LOOSENED PER INSTRUCTIONS VERIFY OPENING OF ECONOMIZER HOODS VERIFY INSTALLATION OF EXHAUST HOODS CONFIRM THAT TUBING FOR SPACE AND SUPPLY DUCT PRESSURES HAS BEEN INSTALLED VERIFY THAT CONDENSATE CONNECTION IS INSTALLED PER INSTRUCTIONS VERIFY THAT POWER SUPPLY MATCHES UNIT DATA PLATE VERIFY THAT ALL ELECTRICAL CONNECTIONS AND TERMINALS ARE TIGHT CHECK GAS PIPING FOR LEAKS 48FK JK ONLY CHECK THAT INDOOR AIR FILTERS ARE CLEAN AND IN PLACE CHECK FAN WHEEL AND PROPELLER FOR LOCATION IN HOUSING ORIFICE AND VERIFY SET SCREWS ARE TIGHT VERIFY THAT FAN SHEAVES ARE ALIGNED AND BELTS ARE PROPERLY TENSIONED OPEN SUCTION DISCHARGE AND LIQUID LINE SERVICE VALVES CHECK COMPRESSOR OIL LEVEL SIGHT GLA
65. etback heating TEMP RESISTANCE VOLTAGE F Ohms DROP v Fig 23 Occupied Unoccupied Switch with 31 0 16813 8 3 582 Night Setback Thermostat 32 0 16345 7 3 553 33 0 15892 2 3 523 34 0 15452 7 3 494 034 048 TB3 35 0 15026 7 3 464 054 104 TB4 FIELD 36 0 14613 9 3 434 SUPPLIED 37 0 14213 6 3 404 POWER 38 0 13825 5 3 373 SOURCE 39 0 13449 2 3 343 40 0 13084 2 3 312 41 0 12730 1 3 281 42 0 12386 6 3 250 N O 43 0 12053 3 3 219 44 0 11730 0 3 187 SIONAL i 45 0 11416 1 3 156 TERMINALS 46 0 11111 5 3 124 47 0 10815 8 3 093 Ne 48 0 10528 7 3 061 49 0 10250 0 3 029 Fig 24 Heat Interlock Relay 50 0 9979 3 2 997 51 0 9716 5 2 965 52 0 9461 3 2 933 034 048 TB3 53 0 9213 4 2 901 054 104 TB4 54 0 8972 6 2 869 T10 55 0 8738 6 2 837 56 0 8511 4 2 805 57 0 8290 6 2 772 P7 58 0 8076 1 2 740 59 0 7867 7 2 708 60 0 7665 1 2 676 ee 61 0 7468 3 2 644 BEEN 62 0 7277 1 2 612 Fig 25 Accessory Reset Board 930 7091 2 2 581 64 0 6910 6 2 549 65 0 6735 1 2 517 66 0 6564 4 2 486 67 0 6398 6 2 454 EXAMPLE 68 0 6237 5 2 423 T10 desired set point is 70 F 69 0 6080 8 2 391 T10 from Table 4 for 70 F is 5929 ohms 70 0 5928 6 2 360 7 13 084 5929 71 0 5780 6 2 329 7 7155 ohms 72 0 5636 8 2 299 Using an ohmmeter set the 7 potentiometer to 73 0 5497 0 2 268 7155 ohms to achieve a reset initiation set point of 70 F 140 5361 2 2 237 7
66. even mo mentarily until all items on the Controls Start Up Check list in installation instructions and the following steps have been completed Verify unit has been installed per the Installation Instruc tions included in the unit installation packet 2 Verify that all auxiliary components sensors controls etc have been installed and wired to the unit control boxes per these instructions the unit Installation Instructions and the unit wiring label diagrams 3 Verify that air pressure hoses static duct etc are prop erly attached routed and free from pinches or crimps that may affect proper control operation 4 Set any control configurations that are required field installed accessories etc The unit is factory configured for all appropriate factory installed options with the ap plicable controls programmed to the default values 5 Check and adjust unit set points See Table 9 6 Check tightness of all electrical connections 7 Perform quick test see Quick Test Program section on page 31 Table 9 Potentiometer Inputs and Ranges CONTROL POTENTIOMETER DESCRIPTION LOCATION VALID DEFAULT VALUE RANGE Supply Air Display 45 F if 22 lt PI lt 45 E Set Point Board 45 to 70 F 70 F if P1 gt 70 F OR IF P1 lt 22 F Reset Limit a Oto 80 F None limited to 70 F maximum Demand Limit P4t Single Step Main Control Box 0 to 100
67. f measured temperature of a thermistor is less than 60 F 363 000 ohms or greater than 180 F 585 ohms the appropriate sensor error code Table 22 will be displayed when the display button is pushed The unit will be shut down Thermistor failures will automatically reset once the error has been corrected If a failure occurs the following are pos sible causes Thermistor or Resistor Failure A shorted or open ther mistor or resistor will cause the failure Wiring Failure If a wiring error exists that causes a shorted or open circuit this will cause a failure Processor Board Failure If circuitry on processor board fails this could cause an error The codes are designated as follows Code 71 Supply Air Thermistor Failure Code 72 Return Air Thermistor Failure Code 73 Not used Code 74 Not used Code 75 Circuit 1 Saturated Condensing Thermistor Code 76 Circuit 2 Saturated Condensing Thermistor CODE 81 RESET THERMISTOR OR POTENTIOM ETER FAILURE This is a unique code since the reset temperature potentiometer P7 is in series with the space temperature thermistor T10 If either one of these compo nents fail reset will be terminated This error will automati cally reset once the situation is corrected If an error is detected the most probable cause is one of the following Thermistor Failure A shorted or open thermistor will cause the failure Potentiometer Failure If the potentiometer is out
68. g point device with an internal brake and spring re turn Its position is determined by the sequencing of relays EOR Economizer Open Relay and ECR Economizer Close Relay The economizer s current position is sensed by the processor board through position feedback potentiometer P2 Whenever the economizer position potentiometer signal is not consistent with the processor board s commanded po sition a fault condition is determined by the processor board and an alarm signal is initiated The processor board also attempts to return the economizer damper to its fully closed position during this fault condition by energizing the ECR relay Any attempt to effect an external control of the econo mizer actuator will lead to an alarm condition and an auto matic response by the unit control to attempt to close the dampers Smoke Control Modes It is common practice to use rooftop units for aid in building smoke control in the event of a building fire The available functions include Fire Shutdown Pressurization Evacuation and Smoke Purge These functions are enhanced when multiple rooftop units are used to zone a building Implementation of the various Smoke Control modes on these units requires the installer to modify the unit wiring to add contacts via either manual switches or relays that will selectively interrupt and override standard factory control se quences See Table 5 FIRE SHUTDOWN MODE Fire Shutdown mode termi
69. gt RED lt E RED e CONTACTS FOR BUILDING PRESSURE MODE amp SMOKE PURGE MODES 1 DD ORN anis FOR PLI4 2 PLIB 2 PL17 2 PLIS 2 ax om ak 13 ew LODO ak YD aa 5 amp SIK TH ECR PL14 3 E HE BLE Je ud wr mwe K3 vio WHT 85 87 89 orca w EXD 09 35 37 39 m ku CIA EC cm 25 27 29 TIT Fig 55 Typical Wiring Schematic 48FK JK and 50FK FY JK JY Units 054 074 Shown LS 18V an 65 67 69 11 13 15 PROCESSOR BOARD 0 SETPOINT MEC go BOARD amp RED Ko RED YEL KO GRA aK EC 95 97 99 E 75 77 73 59 1 52 PL2 5 Li 301 401 500 504 BB c BLU giri lt vio o 1 5 PLI S K 2 e Lo n A Economizer OPTION 17 5 15 lt lt Zo FIELD REMOVE JUMPER AND ADD SMOKE FIRE vio 3 gt vio vio ALARM CONTACTS NORMALLY CLOSED I EC PLi7 4 PL15 4 amp o 125 127 129 Lo ee exce e m o P ACCESSORY 5 ECONOMIZER OPTICN BOARD ECON MTR 2 125140148 PL16 5 PL14 5 1 v0 H v10 1 amp VIO 115 117 119 4 RED RED RED PLIB 4 PLI4 4 115 117 118 PNY PINK 2 amp o P
70. guide vane differential pressure switch for the 034 048 units is located in the back of the unit in the auxiliary control box Its lo cation is not shown in this figure Fig 37 Inlet Guide Vane Motor 48FK JK 50FY JY and 50FJX FJY FKX FKY034 074 Units LINKAGE ARM INLET GUIDE VANE MOTOR Fig 38 Inlet Guide Vane Motor Size 078 104 Units CAPACITOR NULL ADJUSTMENT COM N C N O 7 jeu DECREASE NOILVM8IA OL parans Vo vduns NO 1 LON OG SET POINT ADJUSTMENT SET POINT INDICATOR LEGEND COM Common N C Normally Closed Normally Open Fig 39 Differential Pressure Switch for Inlet Guide Vane and Static Pressure Control Option and Modulating Power Exhaust Option O HZ PERCENT SECONDS KW AMPS VOLTS gt i RUN SETUP PROGRAM MONITOR READ WRITE STOP RESET O Locaurewore MANUAL AUTO SPEED CTRL RUN MODE Fig 40 Variable Frequency Drive Keypad DETERMINE VED SET POINT The unit of measure for the Duct Pressure set point at the VFD is output frequency Hz representing the desired DP set point DPSP in inches of water gage in wg To convert desired DPSP into the VED set point refer to Table 13 Locate the pressure value in the table closest to the desired DPSP for
71. he highest code indicated on the display will be 6 for the 034 038 and 048 088 units 4 for the 044 units and 8 for the 104 units Capacity steps are directly related to pin terminal connec tor J6 output At step zero the unit has no mechanical cool ing on and the economizer may or may not be operating depending on the outdoor air conditions Once a cooling load is detected T1 thermistor reads above the supply air set point the economizer will begin modulating to meet the 34 load if the outdoor enthalpy is good As long as the outdoor air enthalpy is acceptable no mechanical cooling will take place until the economizer dampers are fully open The rest of the steps and the operational sequence vary due to the number of compressors and unloaders Refer to Operating Sequence section on page 35 for the unit stages of operation CODES 20 THROUGH 30 AND 88 OPERATIONAL STA TUS These codes indicate special operational modes such as initialization morning warm up temperature reset de mand limit or an internal failure of the board Codes 23 25 and 27 29 are not used on these units Initialization When the control is turned on the display shows a for approximately 2 minutes to indicate that the control is in the initialization mode During this time the economizer dampers open and close to determine the resis tance range of the economizer position potentiometer P2 for full economizer operation The processor loads th
72. heating the space until the return air temperature is within 2 F of set point The unit will then shut off the heat and continue to circulate air The unit will cycle in and out of the heating mode until the return air tem perature reaches the morning warm up set point P6 Once morning warm up has been terminated the unit cannot re turn to morning warm up until the unit is powered down and restarted This action signals a return to the Occupied mode NOTE Occupied heat is NOT AVAILABLE on these units Once out of the morning warm up routine the unit will begin its cooling routine based on the supply air set point P1 At step zero the unit has no mechanical cooling on and the economizer may or may not be operational The econo mizer will move to the minimum position determined by po tentiometer P5 if no cooling load is detected Once a cooling load is detected by thermistor T1 sensing a temperature higher than the cooling demand set point P1 the economizer will begin modulating to meet the load if the outdoor enthalpy is good The processor will attempt to maintain a supply air temperature of P1 2 F by modulating the economizer dampers No mechanical cooling will take place until the econo mizer dampers are fully open if the outdoor air enthalpy permits If the economizer is unable to meet the cooling demand then mechanical cooling is used in conjunction with the economizer If the economizer is unable to meet the load
73. hould install start up and service this equipment When working on this equipment observe precautions in the literature on tags stickers and labels attached to the equip ment and any other safety precautions that apply Follow all safety codes Wear safety glasses and work gloves Use care in handling rigging and setting this equipment and in han dling all electrical components A WARNING Electrical shock can cause personal injury and death Shut off all power to this equipment during installation and service There may be more than one disconnect switch Tag all disconnect locations to alert others not to restore power until work is completed A WARNING This unit uses a microprocessor based electronic con trol system Do not use jumpers or other tools to short out components or to bypass or otherwise depart from recommended procedures Any short to ground of the control board or accompanying wiring may destroy the electronic modules or electrical components GENERAL IMPORTANT This literature contains controls operation and troubleshooting data for 48FK JK and SOFK FY JK JY variable air volume rooftop units Use this guide in conjunction with the separate Installation Instructions literature packaged with the unit Carrier 48FK JK and 50FK FY JK JY units provide ven tilation cooling and heating when equipped in Variable Air Volume VAV applications These units contain factory
74. ialization To initiate Quick Test press the Display button while 20 is displayed Temperature Reset in effect Demand Limit in effect Morning Warm Up in effect Internal failure detected Self diagnostic mode in effect Restart Procedure Before attempting to restart the machine check the display for alarm codes to determine the cause of the shutdown If the unit circuit or compressor stops more than once as a result of a safety device determine and correct the cause before attempting to start the unit again After the cause of the shutdown has been corrected unit restart may be automatic or manual depending upon the fault Table 20 Controls Troubleshooting SYMPTOM S Controls do not seem to be operating Evaporator fan does not run Remote on off function may be keeping controls off 1 Circuit breaker open PROBABLE CAUSE S 2 Inverter overload if equipped Compressor does not run 1 Circuit breaker is open 2 There is no demand for cooling 3 The control is locking out cooling operation 4 Demand Limit in effect Condenser fans do not Circuit breaker is open turn on Cooling demand exists and economizer modulates but compression is not operating Compression cannot be initiated until economizer damper is 9096 open 44 SOLUTION S Check status Find cause and reset circuit breaker Find cause and reset Find cause and reset circuit breaker Correct operatio
75. ied For the VFD to run the following conditions must be met at the VFD 1 Drive enable jumper is installed from terminals CC ST factory supplied see Fig 53 and 54 2 Proper rotation jumper is installed at terminals R CC re verse rotation factory supplied or terminals F CC for ward rotation factory supplied UNIT SIZES JUMPER 034 048 R CC 054 074 078 104 3 Emergency stop jumper is installed from terminals 54 factory supplied 4 A4to 20 mA signal is applied across terminals from pressure transducer factory supplied 5 DIP switch SW1 located on the VFD s printed circuit control panel must be set to indicating usage of a 4 to 20 mA input signal at terminals IV 6 Speed Control located on the VFD s keypad display set for Remote press the Speed Ctrl button until LED Remote is illuminated 7 Programmed according to Carrier defaults 8 Duct Pressure set point established by user or use fac tory default 30 Hz indicating 2 50 in wg see Table 13 VFD Operational Status The VFDs contain ex tensive self diagnostic functions which are accessed through the VFD display panel located on the front of the VFD or at a remote location when the accessory remote display pack age has been installed A CAUTION If using the VFD display panel disconnect all power to the unit and the VFD before entering unit or use the accessory re
76. ilure occurs one of the following is the probable cause DIP Switch 3 If this switch is in the ON position and the accessory board is not installed accessory board is standard on these units so it should always be on the unit Incorrect Potentiometer Setting If potentiometer is turned fully clockwise or counterclockwise potentiometer will be out of the allowable range and an error will result Faulty Wiring If wiring between the potentiometer and the processor board is incorrect an error will occur Potentiometer Failure If potentiometer is shorted or open potentiometer will be out of range and an error will result CODE 87 WARM UP TEMPERATURE SET POINT FAIL URE Applicable only if morning warm up is used Whether or not unit is equipped with electric resistance heaters use of the morning warm up function is recommended if the unit is shut down at night or over weekends In this application cooling will remain off and the outdoor air damper will stay closed until heat load from the occupied space elevates return air temperature to the warm up set point If warm up func tion is used DIP switch 4 must be in the ON position The 47 potentiometer P6 is located on the accessory board If po tentiometer is set at less than 0 F or more than 95 F alarm light will be energized a diagnostic code of 87 will ap pear on the display when display button is pushed and con trol will use a default val
77. imary side 115 v transformer 104 to 127 vac 230 v transformer 207 to 254 vac 5 If primary voltage is not correct check system fuse trans former ON OFF switch and wiring If these are okay contact power company 6 If primary voltage is correct but secondary voltage 24 v 10 is incorrect replace transformer 7 Turn control switch to OFF position Step 2 Check Processor Board Power Supply 1 Set meter to approximately 20 vdc 2 Turn power to OFF position 3 Connect negative lead to TP18 4 Turn power switch to ON position and press display but ton to enter Quick Test mode 5 Check voltage between TP18 and each of the following test pins TEST PIN VOLTAGE DC TP3 10 TP4 12 TP6 5 TP10 5 TP14 12 TP15 12 TP7 5 If not using a digital meter leads must be reversed 6 If voltage is incorrect replace processor board 7 Turn power to ON position Step 3 Check Voltage Tolerance Circuitry 1 Turn power to OFF position 2 Negative test probe on TP18 and system in Quick Test mode 3 Check voltage TP18 to TP9 4 If voltage is greater than 1 vdc recheck transformer input voltage 5 If transformer is okay replace processor board 6 Turn power to ON position Step 4 Check Processor Reset Line 1 Turn power to OFF position 2 Negative probe on TP18 3 Check voltage TP18 to TP11 4 If voltage is greater than 3 vde reset power and recheck
78. imit board see Fig 26 For both types of demand limit the control uses only 80 of the total potentiometer resistance If resistance of poten tiometer is less than 10 or greater than 90 alarm light will be energized a diagnostic code of 85 will be displayed when the display button is pushed and demand limit will be terminated If a failure occurs it is probably due to one of the following Potentiometer Failure If a potentiometer is shorted or open a failure will occur Incorrect Potentiometer Setting A potentiometer turned fully clockwise or counterclockwise will put potentiometer out of range resulting in an error Faulty Wiring If wiring between the potentiometer and the processor board is incorrect an error will occur DIP Switch 5 If DIP switch 5 is in the ON position and potentiometer is not installed an error will occur CODE 86 MINIMUM POSITION ECONOMIZER PO TENTIOMETER FAILURE If potentiometer P5 on ac cessory board setting is less than 0 or greater than 100 alarm light will be energized a code of will be dis played when display button is pushed and economizer out door air dampers will move to the fully closed position The potentiometer full scale resistance is 10 Kohm but when installed in parallel with the other 2 potentiometers on the accessory board measured resistance will be 3 3 Kohm This failure will automatically reset when potentiometer returns to normal If a fa
79. in an accurate reading a high impedance meter such as a digital meter must be used Thermistors in the VAV control system have a 5 vdc sig nal applied across them any time the unit control circuit is energized The voltage drop across the thermistor is di rectly proportional to the temperature and resistance of the thermistor To determine temperatures at the various thermistor lo cations disconnect the thermistor from the processor board and measure the resistance across the appropriate thermistor using a high quality digital ohmmeter Use the resistance read ing to determine the thermistor temperature The microprocessor has been programmed to check the operation of the thermistors If the measured temperature is outside of the range of 24 to 225 F or 98 010 to 282 ohms then it will be treated as a sensor failure and a diagnostic code will be displayed See Table 17 for sensor temperatures versus resistance drop It is also possible to check the op eration of the thermistors using the quick test routine If a thermistor has failed or the wire is damaged replace the complete assembly Do not attempt to spice the wires or repair the assembly Electronic Controls Checkout The following will help determine whether a processor board a relay board dis play set point board accessory board or 2 step demand limit module is faulty Before checking out any board do the following At initial start up enter the Quick Te
80. inals to full open heating positions 3 Supply fan will run If equipped with IGV Control vanes will open If equipped with VFD the VFD will control to duct static set point or best available with all terminals open 4 Exhaust fans will run at maximum capacity 5 Exhaust dampers will open Table 6 Smoke Control Switches Required for Each Mode FIRE EVACUATION SMOKE SW 1 SW 1 SW 2 SW 2 SW 3 SW 5 SW 5 SW 4 Eu NOTE All switches are shown in as installed power OFF or deenergized position In these positions of these modes will be activated normal unit operation is permitted by the base unit controls To initiate any mode all switches listed under this mode in the table must be energized causing the depicted contact position to change from depicted positions to energized positions Switches may be manually or electrically operated 22 Table 7 Switch Functions SWITCH NUMBER CONFIGURATION VOLTAGE FUNCTION SW Deenergize 115 v OFC Comp IFC Electric Heaters SW 2 Deenergize TRAN7 Process Board SW 3 NO Energize EOR Open Economizer Outside Air Dampers sw o 5 __ Energize IFC and CR 3 IGVIVFD SW 5 ONG 15 Isolate IFC and PEC for Separate Operation swe no 46 Energize PEC Power Bhaus SW 7 Open PED at DPS SW 8 Block Auto Close at DPS Due to Low BP SW 9A B A iN iG Signal Room Terminals to Open HIR1 LEGEND BP Building Pressure DPS
81. inimum heating CFM position thus as suring adequate airflow through the rooftop unit during night setback cooling operation During night setback cooling op eration the return air temperature RAT will be well above normal levels The higher RAT means that the air tempera ture leaving the evaporator coil will also be well above nor mal levels This situation is interpreted by the unit control system as a demand for additional cooling stages The unit control responds to this demand by bringing on more stages until typically all stages are active If the VFD is not work ing in step with the refrigeration system demand it is pos sible to produce low suction pressures and local frosting on the evaporator coil during the night setback cooling operation UNIT SUPPLY AIR SET POINT ADJUSTMENT The minimum Supply Air Set Point SASP temperature is es tablished by the setting at Potentiometer 1 on the unit dis play board see Fig 6 The control point can also be adjusted upward by emulating the function of the accessory Space Temperature Reset package The BMS can be used to cause this reset by adjusting the resistance value in a variable re sistance transducer with a 4 to 20 mA or 2 to 10 vdc signal generated by the BMS This emulation requires the following field supplied parts Variable resistance transducer Kele RES 1 or equivalent range 0 to 1000 ohms Series resistance with potentiometer suitable for manual adjustmen
82. installed controls which provide full system management The unit controls also perform self diagnostic tests at unit start up monitor operation of the unit and provide alarms Information on system operation and status are sent to the central processors by various sensors that are located at the unit and in the conditioned space Each unit is equipped with a display board Rooftop Information The rooftop controls cycle supply fan motor compressors and unloaders to maintain the proper temperature conditions The controls also cycle condenser fans to maintain suitable head pressure Safeties are continuously monitored to prevent the unit from oper ating under abnormal conditions The controls provide con trol of economizer and cycle or control heating as required The controls also allow the service person to operate a quick test so that all the controlled components can be checked for proper operation IMPORTANT The field supplied and installed switch or timeclock MUST BE CLOSED to put unit into the Occupied mode Unit WILL NOT START until this is accomplished See base unit installation instructions literature for details VAV Control System The 30 to 100 ton VAV roof top units contain a microprocessor based electronic control system that controls and monitors the rooftop unit functions The VAV control system is composed of several components processor board relay board display board thermistors compresso
83. iometer fails during operation indicating that the damper blades are stuck If either situation occurs the pro cessor will try to drive the economizer dampers closed P3 RESET LIMIT This potentiometer is located on the accessory board provided standard from the factory in the unit main control box and establishes the maximum amount of reset that can be applied to the supply air set point P1 Reset is limited by the PI default of 70 F This potentiom eter is used only when accessory field installed temperature reset is used If temperature reset is used DIP dual in line package switch 2 must be in the ON position P4 DEMAND LIMIT This potentiometer is located near TRAN4 in the unit control box The demand limit po tentiometer is used only if accessory field installed demand limit is used and if DIP switch 5 is in the ON position For single step demand limit a field installed 5 to 20 Kohm po tentiometer and switch must be used P5 ECONOMIZER MINIMUM POSITION This po tentiometer is on the accessory board provided standard from the factory located in the unit main control box This po tentiometer specifies the minimum opening position for the optional economizer If a fault condition is detected by the processor an alarm condition will be signaled and the econo mizer dampers will close P6 WARM UP SET POINT This potentiometer is on the accessory board provided standard from the factory lo
84. ion EVACUATION MODE Evacuation mode removes smoke or undesirable air from interior spaces without reintroducing unsuitable air Factory installed optional economizer with optional or accessory power exhaust are required for this func tion Evacuation is accomplished by e turning supply fan off opening the economizer option required for this function running the exhaust fans must be provided via option or accessory opening the exhaust dampers SMOKE PURGE MODE Smoke Purge mode removes smoke from the interior spaces and replaces it with fresh out side air Factory option economizer with optional or acces sory power exhaust are required for this function Smoke purge is accomplished by e turning supply fan on opening the economizer option required for this function running the exhaust fans must be provided via option or accessory opening the exhaust dampers INSTALLATION To enable one or more of the possible smoke control modes available with these units determine the switches required for the desired mode s from Table 6 field supply and install the appropriate switches and field wire per Fig 32 Switch functions are shown in Table 7 Table 5 Smoke Control Modes FUNCTION Smoke Purge Pressur ization Fire Shutdown Evacuation Supply Fan On IGVVFDt Open On Economizer Open cum dou Exhaust Exhaust Closed Closed Open Open D
85. ion and range data are shown below SUPPLY AIR SET POINT Leaving Air Temperature P1 This potentiometer establishes the set point for cooling cycle operation of the VAV unit The VAV control uses valid control range of 45 to 70 F and the potentiometer has a valid range of 22 to 70 F If the set point is between 22 and 45 F the control will use a value of 45 F If the set point is outside the valid range less than 22 F or greater than 70 F an alarm condition will be signaled and a default value of 70 F will be used ECONOMIZER MINIMUM POSITION P5 This po tentiometer specifies the minimum opening position for the optional economizer during running periods It has both a valid range and an operational range of 0 to 100 SASP RESET TEMPERATURE P7 This potentiometer establishes the space temperature at which the control will initiate the reset of the SASP i e the unit control begins to raise the base SASP to prevent overcooling of the space The potentiometer has a valid range of 40 to 100 F Refer to Space Temperature Reset section on page 16 for further dis cussion of SASP Reset operation RESET LIMIT P3 Used in conjunction with P7 poten tiometer this potentiometer establishes the maximum tem perature for the modified SASP value during the Reset func tion This potentiometer has a valid range of 0 to 80 F DEMAND LIMIT SINGLE STEP P4 This potentiom eter establishes the maximum am
86. ior to the quick test See Configuration of Header and DIP Switch Assembly section on page 5 for factory switch settings The DIP switch functions and display codes are shown in Table 15 2 Quick Test Steps 1 4 2 3 Thermistor and Set Point Potentiometer Check In these steps the microprocessor checks resistance val ues of all sensors and set point potentiometers to ensure that they are functional connected properly and set within proper range for unit configuration Nominal resistance values for all sensors range from 363 000 to 219 ohms in accordance with Table 18 Normal dis play code for good sensors and potentiometers is 1 A dis play code of 0 indicates a faulty potentiometer thermistor or wiring A 0 display also indicates that option is not being used Table 16 shows thermistor and set point potentiometer functions and quick test display codes DIP EC VAV Units are not equipped with oil pressure switches QUICK TEST STEP NO BE LEGEND Table 15 Quick Test Unit Configuration and Switch Check NORMAL DISPLAY 9 o e Dual In Line Package Enthlapy Control Variable Air Volume e SE eJ SJ e E 8 t Type Unit Air Cooled VAV No of Compressors No of Unloaders 034 038 048 088 044 104 60 Hertz Power 0 No Reset Switch Off 1 Reset
87. is an integral part of display board and cannot be replaced separately ACCESSORY BOARD CHECKOUT The accessory board can be completely checked using quick test steps 2 0 2 2 and 2 3 It can also be checked out as follows 1 Remove the accessory board connector from the proces sor board and connect an ohmmeter to terminals 3 and 4 on the connector Numbers are marked on the connector See Fig 15 2 Set the meter to 10 000 ohms The resistance value ob tained should be 3 333 ohms Adjust the potentiometers and the resistance value should not change 3 Connect the ohmmeter to terminals 3 and 6 As the reset limit potentiometer is turned clockwise resistance should increase from 0 to approximately 3 400 ohms 4 Connect the ohmmeter to terminals 3 and 5 As the econo mizer minimum position potentiometer is turned clock wise resistance should increase from 0 to approximately 3 400 ohms Connect the ohmmeter to terminals 3 and 2 As the warm up set point potentiometer is turned clockwise resistance should increase from 0 to approximately 3 400 ohms If any of the Steps 1 through 5 result in any other ohm reading replace the board it cannot be serviced TWO STEP DEMAND LIMIT CONTROL MODULE DLCM TROUBLESHOOTING If a problem is suspected in the DLCM board use the following test procedure The board can only be checked when it is connected to the processor and the processor is energized so that the DLCM i
88. ischarged The lamp is located on the upper right hand corner of the terminal block If still lit wait until lamp goes completely out This may take several minutes 11 Replace jumper to terminals ST CC 12 Replace VFD cover 13 Turn on IFCB to enable the drive For additional information on the VFD including basic troubleshooting factory jumper arrangements and Carrier factory defaults programming refer to Troubleshooting Vari able Frequency Drive section page 52 IMPORTANT The Carrier factory default values for the VFD may be different than the default values of the manufacturer Refer to the Service section when checking default values 252000 P24 RES RR 1 52 292999 4 RCH P24 LOW LOW 5 RX IV FP FLB FLA REMOVE JUMPER Fig 41 Jumper Removal to Disable Motor Table 13 VFD Set Point Frequency Command for Duct Pressure En an oo 9 4 T 29 2 104 Qa 3s 48 228 7 2 05 6 2 3 120 Qm 9 64 2 128 10 o 72 so 39 136 12 6 o ss 39 144 1 50 18 8 8 42 15 2 Table 14 Changing the VFD Set Point Frequency Command KEY OPERATION XX X or OFF i 0 FC 45 0 flashing XX X or OFF Choose set point from Table 13 according to desired duct pressure Modulating Power Exhaust Option or Acces sory The Modulating Power Exhaust system wi
89. ital dis play codes press the button located to the right of the LED display set point board in the control box See Table 21 for Operational Status Codes See Table 22 for Diagnostic Codes Complete Unit Stoppage If the unit is off there are several conditions that can cause this situation to occur Remote ON OFF circuit in Unoccupied mode Unit ON OFF switch moved to OFF position Programmed schedule at the timeclock General power failure Blown fuse in the control power feed Open control circuit fuse Operation of the unit blocked by the demand limit function Unit supply air temperature T1 thermistor failure Supply air fan is not operating High duct static pressure Single Circuit Stoppage If a single circuit stops there are several potential causes Open contacts in the compressor high pressure switch Low refrigerant pressure Thermistor failure Unit supply air temperature thermistor T1 failure Compressor circuit breaker trip Operation of the circuit blocked by the demand limit function Table 21 Operation Status Codes CODE MEANING 0 cooling stages active 1 cooling stage active 2 cooling stages active 3 cooling stages active e E Lel amp 8 S S BI 4 cooling stages active 5 cooling stages active 6 cooling stages active 7 cooling stages active 8 cooling stages active Initialization mode Allow 2 minutes for init
90. itch positions Reconnect power after all changes have been made Set the potentiometers DLCM P1 and DLCM P2 to de sired capacity reduction values Check the operation of demand limit function by using the Quick Test procedures CONFIGURATION Single Step Demand Limit Field installed potentiom eter P4 establishes capacity reduction value for demand limit operation Set this potentiometer between 0 and 100 The exact percentage of capacity reduction differs depending on the number of capacity steps Two Step Demand Limit Potentiometer 1 and P2 lo cated on the accessory demand limit control module estab lish the capacity reduction values for each step of demand limit Set potentiometer DLCM P1 between 50 and 100 Set potentiometer DLCM P2 between 0 and 49 The ex act percentage of capacity reduction differs depending on the number of capacity steps OPERATING SEQUENCE Single Step Demand Limit If the field control switch to the wiper arm terminal is open all capacity stages will be available no demand limit in effect When the field control switch is closed the compressor cooling capacity is reduced by the amount set on potentiometer P4 When demand limit is in effect the LED display will show code If a potentiometer setting or input is out of range the control will terminate the demand limit function and show code at the display LED Two Step Demand Limit If the field control switches are both
91. ken in a pattern to indicate several unique characteristics of the unit The configuration header is factory set and should not be changed Changing the factory setting may cause the unit to malfunction The DIP switches configure the unit for several field installed options as well as for several other options that may be unique to the unit The DIP switches are located un der a plastic enclosure which must be removed for access The switches can be field adjusted but must be adjusted only when the unit control circuit breaker is off Relay Board The relay board is used to control 24 v and 115 v loads See Fig 5 The relay board is connected to the processor board by a ribbon cable at pin J9 Electrical connections to the relay board are made through pins J5 115 v and J6 24 v The relay board has eight 24 v relays and five 115 v relays See Table 3 Display Board The display board is located in the main unit control box and is connected to the J10 port of the processor board through a ribbon cable The display board contains the supply air set point potentiometer P1 a 2 digit LED display and the display button see Fig 6 The LED display is used to convey the operating information and op erational error codes Thermistors The processor uses up to 5 thermistors to sense the temperatures at various points in the system See Table 1 and Fig 7 14 All the thermistors have identical temperature versus resistance and v
92. l then operate in the correct direction To set the duct static pressure perform the following steps The factory setting is 2 5 in wg The duct transducer has a range from 0 to 5 in wg The transducer output is 4 to 20 mA therefore 0 to 5 in wg is proportional to the 4 to 20 mA and must be expressed to the VFD in terms of per centage of the frequency range Refer to Table 13 The set point value is a percentage of the maximum output fre quency Locate the duct static pressure closest to that de sired and use the corresponding set point value If necessary interpolation between duct static pressures is permissible A WARNING Factory installed optional VFD is located near the sup ply fan and motor During any service work or pro gramming at the VFD operation of the fan and motor is not desirable and may be dangerous Either disable the unit supply fan following instructions below or in stall the accessory VFD remote display accessory 28 INLET GUIDE VANE DIFFERENTIAL PRESSURE SWITCH SIZES 054 074 wae IF INLET GUIDE VANE MOTOR The inlet guide vane differential pressure switch for the 034 048 units is located in the back of the unit in the auxiliary control box Its lo cation is not shown in this figure Fig 36 Inlet Guide Vane Motor 50FK JK034 074 Units INLET GUIDE VANE DIFFERENTIAL PRESSURE SWITCH SIZES 054 074 INLET GUIDE VANE MOTOR The inlet
93. ll main tain space pressure by modulating power exhaust fan no 1 and staging power exhaust fan no 2 Building pressure set point is established at the modulating power exhaust differ ential pressure switch DPS SIZE 034 048 UNITS The modulating power exhaust dif ferential pressure switch is located in the auxiliary control box mounted in the corner next to the power exhaust motor door To gain access to this control box remove the auxil iary control box cover When replacing cover be sure to prop erly secure it in order to prevent water from being drawn into the unit See Fig 33 SIZE 054 104 UNITS The modulating power exhaust dif ferential pressure switch is mounted below the auxiliary con trol box next to the access door labeled FILTER SECTION See Fig 35 30 EXPLANATION Standard Monitor Mode output frequency If drive is disabled display will read OFF If enabled display will show current output frequency Pressing arrow key once will display the current frequency setpoint Pressing up down arrow keys changes the desired setpoint When R W is pressed the parameter name FC and the new value 45 0 will alternately flash to indicate that the new value has been Stored After 2 cycles the display will return to the standard monitor mode Standard Monitor Mode output frequency If drive is disabled display will read OFF If enabled display will show current output frequency DIFFERENTIAL PRESSURE SW
94. ltage reading is dependent on the meter s impedance Readings may vary with different meters 6 If voltage is not correct replace processor board Step 7 Potentiometer Connection Checkout Turn power to OFF position Remove plug connection from pin terminal strip J3 Connect negative meter lead to terminal 2 of J3 Turn switch to ON position and go into Quick Test mode Place the other lead on terminals shown in table below and check voltage at pin terminals on terminal connector J3 WN PIN TERMINAL VOLTAGE DC 1 2 5 3 5 6 5 8 2 5 10 2 5 12 5 13 2 5 14 2 5 Voltage reading is dependent on the meter s impedance Readings may vary with different meters 6 If voltage is not correct replace processor board Step 8 Thermistor Input Connector Checkout 1 Turn power to OFF position 2 Remove the thermistor connections from pin terminal con nector J1 and mark them for later replacement 3 Connect the negative test lead to test pin TP18 4 Turn power to ON position and enter the Quick Test routine 5 Place the other lead on terminals shown in Table 24 and check the voltages 6 If voltages are incorrect per Table 24 replace processor board 7 Turn power to OFF position and replace the thermistor connections removed in Step 2 8 Turn power to ON position Fig 51 Dis
95. mote display module Disable supply fan and motor operation before accessing VFD mounted dis play module When power is first supplied to the VFD the display au tomatically starts with the frequency monitor function of its standard monitor mode In the frequency monitor function the output frequency is displayed Push the S P M Setup Program Monitor key to switch to the Mode Selection menu Push the S P M key again to toggle the display back to the standard monitor mode From the Mode Selection menu the service person can view all of the monitored status variables including up to four user selected variables and any trip history in the memory Refer to the separate VFD Operation Manual for detailed instructions on accessing diagnostic information initiating troubleshooting and clearing any trip history Restoring Factory VFD Defaults The original factory configuration values are saved in the memory of the VFD and can be restored by the service person if required There are two types of saved file data Carrier factory set tings factory programmed settings made to the VFD which apply specifically to the unit it is installed on and standard defaults for general Carrier unit use The Carrier factory settings are maintained as user set tings These can be restored by entering the Setup mode in the S P M menu and setting parameter tYP 6 on the keypad display This will recall the specific factory defaults for this u
96. mperature at T10 drops to the set point at P7 When Temperature Reset is active the LED light emitting diode display will show code 21 Automatic adjustment of supply air temperature set point will end when modified SASP equals reset limit set point at P3 See formula for automatic modification of SASP in Controls Installation Space Temperature Reset section on this page CONTROLS INSTALLATION The VAV units may be used in applications with addi tional control features options or accessories Refer to the appropriate accessory installation instructions for more in formation on installing that accessory Unit control box com ponent arrangement is shown in Fig 20 22 Control options and accessories available for VAV units are smoke control modes differential enthalpy sensor electric heaters sizes 034 074 only modulating power exhaust Motormaster I control space temperature reset night setback thermostat field supplied single step demand limit two step demand limit inlet guide vanes variable frequency drive variable frequency drive remote display kit Control Wiring A switch or timeclock field sup plied must be wired in to control when unit will go into and out of Occupied mode Connect switch or timeclock be tween terminals 1 and 2 on terminal block 3 sizes 034 048 or terminal block 4 sizes 054 104 in unit control box See Fig 23 The circuit potential is 24 v Variable air volume units equipp
97. mperature reset package is used It provides occupied space temperature information to the pro cessor which determines whether or not reset is required The thermistor is remotely mounted outside the unit in the conditioned space Table 3 Output Pin and Terminal Assignments OUTPUT PIN emma _ _ RATING DEVICE Stage 1 di Compressor Relay K1 CR1 Stage 2 46 2 Compressor Relay K2 U2 Stage 3 J6 3 Compressor Relay K3 Ui Stage 4 ee Compressor Relay K4 t 24 vac Not Used Stage 5 J6 5 Compressor Relay K5 t CR2 Stage 6 J6 6 Compressor Relay K6 t Not Used J6 7 Economizer Open Relay K7 Economizer Open Relay K7 Relay EOR J6 8 Economizer Economizer Close Relay K8 Economizer Close Relay K8 ECR J5 1 Supply Fan Relay K9 IFC J5 2 Morning Warm Up Relay K10 HIR EE 1 Condenser J5 3 Fan EE K11 115 vac OFC2 OFC3 tt 2 Condenser gt Fan K12 J5 5 External Alarm Relay K13 Alarm External Alarm Relay K13 K13 ALM LEGEND Circuit 1 Circuit 2 er Sn Rela U2 is not used on 044 units ey TTOFC2 on 034 048 units OFC3 on 054 104 units ECR Economizer Close Relay Used on 054 104 units onl EOR Economizer Open Relay y HIR Heat Interlock Relay IFC Indoor Evaporator Fan Contactor OFC Outdoor Condenser Fan Contactor U Unl
98. n Check rotating display for alarm codes Resolve alarm cause and reset control by changing to standby and back to run mode 4 Check Demand Limit Settings Find cause and reset circuit breaker Correct operation Diagnostic Codes Diagnostic codes are warnings of abnormal or fault conditions and may cause either one circuit or the whole unit to shut down They are assigned code numbers as described below Table 22 contains a description of each diagnostic code error and possible cause Manual reset is accomplished by moving the ON OFF Switch to the OFF position then back to ON The 2 digit LED display is used to display the diagnostic codes and the alarm light located next to display is ener gized whenever a diagnostic code is tripped When a prob lem is suspected always check the display first for diagnos tic information NOTE Codes 53 54 57 58 61 62 65 69 73 74 and 77 80 are not used on these units IMPORTANT The microprocessor memory and the display will be cleared if the power to the microproces sor is shut off DO NOT attempt to bypass short or modify the control circuit or electronic boards in any way to correct a problem This could result in a haz ardous operating condition CODES 51 52 55 56 COMPRESSOR FAILURE If con trol relay CR opens while compressor should be operating compressor will stop and microprocessor will energize alarm light and display
99. nit Occasionally it may be necessary to restore the VFD de faults to the general Carrier use values These are stored in an OPTION ROM read only memory chip However some variables may need to be manually changed to match the specific unit s factory default settings To recall the general Carrier defaults enter the Setup mode and set parameter tYP 3 Refer to Table 30 for items requiring manual adjustment Table 30 Required User Adjusted Defaults SIZES ITEM All Motor overload settings see Table 31 1 Check jumper CC F 2 Gr UT bLSF 1 054 104 3 Gr SF Sr n 4 Gr SF SrN1 5 SEtP tYP 5 Save User Settings Table 31 Motor Overload Settings UNIT SIGNATIE ETA DESIGNATION UNIT 48 50 DESIGNATION vo lien SETTING Model No Model No Een 12 ESE 15 FREVIK 5 N 82 5 o 6 800 80 0 80 0 FKX FKY BEN SEMI l UNI RE 80 0 MIKY 6 780 LEGEND IFM Indoor Fan Motor Unit Wiring typical wiring schematic is shown in Fig 55 LEGEND AND NOTES FOR FIG 55 Alarm LAT Leaving Air Temperature Contactor LPS Low Pressure Switch Circuit Breaker MTR Motor Control Circuit Breaker MV Main Valve Compressor NC Normally Closed Crankcase Heater NO Normally Open Control Relay OFC Outdoor Fan Contactor Differential Pressure Switch OFM Outdoor Condenser Fan Motor Discharge Pressure Transdu
100. nt level that is typically lower than during normal occupied periods Heating Only mode Some applications also require a limitation on the maximum space temperature during unoccupied periods Cool ing mode Both modes are possible by closing the same con tacts used in the Occupied Unoccupied control or by installing a dedicated contact set in parallel with the Occupied Unoccupied control contacts and using the BMS space tem perature sensing system and its logic to determine when to initiate unit operation Once the unit operation has been initiated by the BMS contact closure the unit operates in its normal occupied mode manner initiating morning warm up if needed as sensed by return air temperature to the unit or cooling controlling to current SASP value The Night Setback Control contacts will interrupt normal unit operation when the BMS senses that space temperatures have returned to unoccupied set point levels and the unit will shutdown normally The contact closure from the BMS must be an isolated contact set normally open suitable for 24 volts AC pilot duty NOTE If the rooftop unit is equipped with a VFD and night setback cooling operation is intended the fan system must be controlled to permit FULL SUPPLY FAN AIR DELIV ERY during unoccupied cooling operation This is most con veniently attained by replicating the HIR relay function of the rooftop unit An HIR control sequence will force all room terminals to their m
101. ntacts An un derlined number signifies a normally closed contact Plain num bers no lines signify a normally opened contact Condenser fan motors are thermally protected Three phase motors are protected under primary single phasing conditions 55 95 DISCONNECT SCHEMATIC 208 230 3 60 OPTION STANDARD FIELD 0 0 SD aie 405 82 aux POWER I oa a 4 ve SUPPEY1 Oi av BLU 435 3 BU HK 1 EE mo RED BT API HED RED FQUIP GND SRN SS BA A BRN 12H F22 BAN ORN ase ORN AB H23 CB2 C2A BK ANANA AN BK IH HED NEL IS Bg 124 2 BLU 6 0 OHH aw RED RED ADA RED BRN IH KJH BRN 1 208 230V 064 074 VED OPTION 208 230 3 50 460 5 60 460 3 60 ALTERNATE STANDARD ALTERNATE 8LK SYEL 5 8 COMP1 1 5 S YEL S BLU BLU 2 2 COMP2 RED BRN ORN Wy RED dp e on 3 2 AMPS PEL i3 ERN 10 4 GAS SECTION SEE LABEL SODWS01612 RED BRN 4 ADD SMOKE FIRE NORMALLY CLOSED IN AND OCCUPIED UNO
102. ntial en thalpy sensor in the return air duct When differential enthalpy control is installed the economizer control will use the air stream with lower enthalpy outside air or return air to pro vide for lower compressor operating costs during integrated economizer cycle operation The differential enthalpy sen sor is installed in the return air duct CIRCUIT 1 1 at CIRCUIT 1 CIRCUIT 2 CIRCUIT 1 088 104 UNITS Fig 14 Thermistor T3 and T4 Locations Size 054 104 Units 11 P6 P3 5 Variable Frequency Drive VFD The optional 32GB500254 VED is used to modulate supply fan airflow to maintain duct static pressure on VAV applications The VFD is located in the supply fan section see Fig 18 and 19 and can be ac cessed by opening the fan section access door 7o The unit is supplied with a pressure transducer capable of measuring from 0 0 to 5 0 in wg The pressure transducer so will send a 4 to 20 mA signal to the to modulate the S PERCENT speed of the indoor fan motor to precisely control the fan to the desired static pressure set point The is factory set p F ECON MIN POSITION at 2 5 in wg duct static pressure Refer to the Operating Se quence section for mor
103. oader J6 5 1 Cooooooo ool12 O ilooooo 00910 LOW VOLTAGE HIGH VOLTAGE RELAY CONNECTOR RELAY CONNECTOR 24V 115 230V TO CR val TO FAN CONTACTORS BBEHBHEHBSS o 9 o o e Kio Kit 2 kis Q Q Q 2 N n n RJ 2 EB 5 5 e 9 a K3 a 4 a je o o Q o o o c 7 c20 c2 Et o a AE o 43 O_O Soo J9 99599 PROCESSOR BOARD RIBBON CABLE 6 IN LENGTH LEGEND CR Control Relay J Terminal Pin Connectors Relay Fig 5 Relay Board P1 SUPPLY AIR TWO DIGIT DISPLAY SET POINT DISPLAY BUTTON POTENTIOMETER cll DISPLAY 20 30 1 0 50 gt 20 10 s COLD TEMP SETPOINT Fig 6 Display Set Point Board Compressor Operation CONTROL RELAY CR This relay provides informa tion to the processor about compressor operation one con trol relay per compressor The relay controls and protects the compressor and also controls the crankcase heater A control signal to check the safety statuses and to start the compressor is sent from the relay board This signal trav els through all of the safeties the high pressure switch and the internal protector where used and on to the control re lay coil Once the control relay coil has been energized the control relay completes a feedback circuit for the processor
104. oltage drop characteris tics and are monitored by the processor for a short or open circuit The valid range for a thermistor is 362 640 to 219 ohms Thermistor details and locations are as follows T1 SUPPLY AIR TEMPERATURE THERMISTOR This thermistor is located in the unit supply fan discharge It provides information for the processor to stage the num ber of capacity steps required to maintain a desired supply air temperature T2 RETURN AIR TEMPERATURE THERMISTOR This thermistor is located in the mixed air portion of the unit cabinet The thermistor s primary function is to provide morn ing warm up information This sensor will also provide dif ferential information for the processor during cooling opera tion such as the rate of change for a capacity step T3 SATURATED CONDENSING TEMPERATURE CIR CUIT 1 This thermistor is located on the condenser coil return bend See Fig 13 and 14 It controls the staging of the unit condenser fans based on the condensing temperature of the refrigerant at the designated position on the condenser coil T4 SATURATED CONDENSING TEMPERATURE CIR CUIT 2 This thermistor is located on the condenser coil return bend See Fig 13 and 14 It controls the staging of the unit condenser fans based on the condensing temperature of the refrigerant at the designated position on the condenser coil T10 RESET TEMPERATURE This thermistor is used only if the accessory te
105. onsists of two parallel and independent belt drive forward curve fans The fans motors and drives are located over the return air opening of the unit in a plenum beneath the outside air intake plenum The fans discharge air hori zontally out the back of the unit through individual baro metric backdraft dampers with hoods See Fig 44 and 45 Operation is interlocked with economizer operation Sheet metal installation is shown in Fig 46 and 47 Fan no 1 is equipped with a variable position discharge damper located in the outlet of the fan housing This damper is controlled by an actuator PEDM based on signals from the building pressure differential pressure switch DPS Avail able range on the DPS is 0 50 to 0 50 in wg adjustable Building pressure is sensed by a pick up field supplied and installed located in the occupied space Operation of the modulating power exhaust is a combi nation modulating staged control with fan no 1 providing modulating control from 0 to 100 and fan no 2 being staged On Off according to damper position on fan no 1 As the economizer actuator opens past 1746 open auxil iary switch DMSI closes energizing fan contactor PECI Fan motor no 1 starts and runs Capacity of fan no 1 is controlled by the position of the outlet damper As building pressure increases above set point the DPS will close its contact and drive the power exhaust damper motor PEDM open until set point is achieved
106. open no power supplied to the Demand Limit Control Module all capacity stages will be available no demand limit in effect When control power is supplied to terminal INI only field switch SW1 closes the first step of the de mand limit is energized and the compressor cooling capacity is reduced by the amount set on potentiometer DLCM P1 When control power is supplied to terminal IN2 field switch SW2 closes the second step of the demand limit is ener gized and compressor cooling capacity is reduced by the amount set on potentiometer DLCM P2 When demand limit is in effect the LED display will show code If a potentiometer setting or input is out of range the control will terminate the demand limit function and show code at the display LED 19 034 048 TB3 054 104 TB4 5 20K a e gt POTENTIOMETER P4 4 E SWITCH geom 3268400274 l15 VOLT EE 2 20 30 m gt 4 10 INT 11 men RTNILS lus vorr a 0 49 INPUT AMP MTA 156 70 2 80 SIGNAL PART 640433 4 int 2 PN m 60 2 RIN2 50 100 Fig 28 Two Step Demand Limit Module r ISV DEMAND LIMIT SWITCH 2 Lice 575 DEMAND LIMIT CONTROL MODULE NOTES 1 Demand limit switches are field supplied and wired 2 Demand limit control module terminal blocks will accept up to 12 gage wire 3 i
107. ories 26 DIP SWITCH NO 1 Supply Air Set Point SASP Reset Type Factory setting is OFF Do not change DIP SWITCH NO 2 SASP Reset Enabled Factory set ting is OFF no SASP reset enabled If SASP reset has been installed enable it by changing switch position to ON DIP SWITCH NO 3 Economizer option If economizer option has been installed this switch will be ON If there is no economizer installed this switch will be OFF Confirm setting per Table 10 Change only if in error DIP SWITCH NO 4 Morning Warm Up For 48FK JK models this switch will be ON morning warm up enabled For 50FK JK units with factory installed electric heaters this switch will be ON For all other units this switch will be OFF If accessory electric heaters are installed for SOFK JK without plenum option change this switch to ON DIP SWITCH NO 5 Demand Limit Factory setting is OFF demand limit not enabled If Demand Limit single step or 2 step accessory has been installed change this switch to ON DIP SWITCHES NO 6 AND NO 7 Unloader Configu ration These are factory set to match unit size Confirm set tings per Table 12 Change only if in error Table 12 DIP Switches SWITCH FUNCTION POSITION MEANING 1 Reset Space or Outdoor Air Reset Mode DO NOT CHANGE 2 Reset On Reset Used Select Off Reset Not Used On Enable Economizer 4 Morning On Enable Morning Warm Up Warm Up Off Disable Morning Warm
108. ount of compressor capac ity permitted by the unit control when single step demand limit operation is implemented by closing contact set to po tentiometer wiper arm This potentiometer is field supplied and installed and will be located in the main control box The valid range is 096 to 10096 which is also the operational range If the wiper arm is open all capacity stages can be used When the wiper arm is closed the capacity is reduced by the amount set on potentiometer P4 DEMAND LIMIT 2 STEP The accessory 2 step demand limit control is a 2 potentiometer system The demand limit control board DLCM accessory board is field installed in the main control box the 2 control poten tiometers are located on DLCM Potentiometer DLCM P1 establishes the maximum amount of compressor capacity avail able when SW1 is closed and has a valid range is 50 to 100 Potentiometer DLCM P2 establishes the maximum amount of compressor capacity available when SW2 is closed and has a valid range is 0 to 49 If no power is supplied to the DLCM all capacity stages can be used When power is supplied to terminal IN1 only the first step of demand limit control is energized and the capacity is reduced by the amount set on potentiometer PI When power is supplied to IN2 or INI and IN2 the ca pacity is reduced by the amount set on potentiometer P2 MORNING WARM UP P6 This potentiometer estab lishes the set point temperature for the
109. oviding a direct 4 to 20 mA signal to the from a BMS with DP logic disable the PID propor tion integrated derivative calculation process feature of the DDC Direct to the VFD Several accessory interface boards are available for the VFDs that permit direct communication between the VFD and several BMS communication sys tems Contact your Carrier representative for information on selecting an appropriate accessory interface board and the name of the local service office for sale and installation of the accessory boards EXTERNAL ALARM SIGNAL The unit controls pro vide an external alarm status signal via a 115 vac output sig nal at the relay board J5 available at TB2 4 and TB2 5 common This signal can be forwarded to the BMS by add ing a signal relay at the alarm output placing its coil across terminals TB2 4 and TB2 5 and using its contacts to control a discrete input to the BMS see Fig 31 The alarm signal output is energized when any of the di agnostic codes is tripped REMOTE ECONOMIZER CONTROL Economizer con trol is tightly integrated into the unit s capacity control al gorithms and diagnostic routines Consequently control modifications that interfere with this standard operating se quence are not recommended Economizer position is determined by the unit processor board based on current outdoor air enthalpy status and cool ing capacity demand The economizer damper actuator is a floatin
110. play Board Pin Terminal Connector 410 Table 24 Pin Terminal Connector J1 Voltages PIN TERMINAL VOLTAGE vdc 0 25 Step 9 Thermistor Input Connector Checkout 1 Turn power to OFF position 2 Disconnect all plugs for pin terminal connector J2 and mark them for later replacement Connect a negative test lead to test pin TP18 4 Turn power to ON position and enter the Quick Test routine 5 Place the other lead on terminals shown in Table 25 and check the voltages 6 If voltages are incorrect per Table 25 replace processor board 7 Turn power to OFF position and replace the plugs re moved in Step 2 8 Turn power to ON position p Table 25 Pin Terminal Connector J2 Voltages PIN TERMINAL VOLTAGE 0 25 v NNNNN a mi mi mi ak RONA 1 If Steps 1 through 9 have been competed and the unit still will not function properly replace the processor board RELAY BOARD TROUBLESHOOTING The relay board contains 13 electromechanical relays The small relays are 24 vac and the large relays are 115 vac These relays are controlled by the processor through the ribbon cable at tached to the relay board 50 The following procedure can be used to check out the op eration of the relays To do this
111. r a field installed timeclock or a field installed switch in the occupied space the unit will be gin its initialization mode A will appear in the display screen and the initial ization period will last approximately 2 minutes During this time the economizer dampers open and close to determine the resistance range for full economizer operation of the econo mizer position potentiometer P2 The processor loads the necessary constants for unit operation and also checks the thermistors and other potentiometers for their values and va lidity After the initialization period the screen goes blank until the display button is pressed A CAUTION Use caution during this time after initialization when the screen is blank because the unit supply and return fans could start at any time Personal injury could result from contact with rotating fans Once the initialization period is complete the supply fan begins operation While the fan is operating the economizer dampers are closed and return air from the building is being circulated After 2 minutes the processor checks the resis tance value of thermistor T2 If T2 temperature sensed is 5 F or more below the set point of the morning warm up potentiometer P6 the unit will begin the morning warm up routine and a will be displayed Unit heat will be energized through the heat interlock re lay HIR and all of the occupied space air terminals open The unit will continue
112. r operation feedback control relay accessory board temperature reset package single step demand limit two step demand limit control module Field installed accessories The VAV control system monitors and controls the fol lowing functions of the rooftop unit supply air temperature unit capacity morning warm up or electric heat if equipped head pressure control fan cycling economizer position diagnostic display unit check out quick test supply air temperature reset if equipped demand limiting if equipped Processor Board The processor board shown in Fig 1 contains the logic and the necessary hardware to drive the outputs and the display board The processor board is enclosed by a sheet metal cover and a heater The heater is controlled by a thermostat to keep the processor temperature above 32 F 0 C electrical connections are made to the processor board through wire and ribbon cables Ji1 CONFIGURATION HEADER 30GB660001 J7 J9 RELAY BOARD DIP EXV CONNECTIOR CONNECTOR SWITCHES o lt Po A E s Q ASSY HT203097 1 037 S J10 DISPLAY B8 M BOARD Ss UAT oo HT203097 1 10 FF CONNECTOR E RE O 203097 1 20
113. replace relay board DISPLAY BOARD CHECKOUT Step 1 Check the Output Voltage from Processor Board to the Relay Board Refer to Step 6 Display Board Con nection Checkout section on page 49 sa Table 26 Terminal Strip J6 Connection Resistance Reading QUICK TEST J6 PIN NUMBERS 12421221224 124125262 72 11023 e fe fe pepe 24 25 fefefefefefe 26 27 fefefefefefefe 28 2 9 0 31 fefefofefefef 32 fefefefefofefe s LEGEND Infinity NOTE Pins shown in boldface type will be energized for only 10 seconds All other pins will be energized continuously while at the proper quick test step The control will remain in the Quick Test mode for only 10 minutes unless the display button is pressed Table 27 Terminal Strip J5 Connector Resistance Reading J5 PIN NUMBERS QUICK TEST STEP NO 2 9 to 3 3 LEGEND o Infinity Step 2 Check the Display LEDs 1 Enter Quick Test mode 2 If is not displayed replace display board Step 3 Check Set Point Potentiometer Advance the dis play to quick test step 1 9 to determine if this potentiometer is set and connected properly Step 4 Check Display Switch Press switch If switch does not click it is faulty and the display will be energized continuously The switch
114. ressed during the initialization period of the processor the unit will run its self diagnostic routine When this is in effect an will appear in the display screen CODES 51 THROUGH 87 DIAGNOSTIC INFORMA TION These codes indicate diagnostic information when there is a unit problem such as a faulty thermistor potenti ometer or compressor fault Refer to Diagnostic Codes sec tion on page 45 for more details Codes 53 54 57 58 61 62 65 69 73 74 and 77 80 are not used on these units Under normal operation only the stage number is dis played when the display button is pressed If a status or over load code is displayed the display will rotate every 2 sec onds and will display up to 3 codes Overload information takes priority over all other codes The codes are stored in the microprocessor as long as the board remains energized Operating Sequence The sequence presented be low assumes that the unit is equipped with heat for morning warm up and an economizer If these items are not enabled with the appropriate DIP switches the processor bypasses these subroutines This sequence is also based on an EPROM erasable programmable read only memory processor chip with the identification HT204485 1 XX where is re placed by a 2 digit number representing the current software version See Fig 1 for EPROM chip location When power is applied to the occupied mode relay OMR through the closure of eithe
115. s field wiring Fig 29 115 Volt Field Wiring to Accessory 2 Step Demand Limit Control Module Control From Remote Building Management Sys tem BMS The unit control system is not a commu nicating control system and it cannot be accessed directly by a DDC Direct Digital Control control system or by a BACnet communication system However it is possible to control some functions of these units via 4 to 20 mA or 2 to 10 vdc signals and discrete inputs relay contact closures Functions that can be managed from or accessed from an external control system include Occupied Unoccupied Status Night Setback Control Unit Supply Air Set Point Adjustment Demand Limit 1 stage or 2 stage Supply Duct Pressure Set Point Adjustment External Alarm Signal Remote control of the economizer cycle on these units is not recommended Refer to the Operating Sequence section on page 35 for a discussion on the economizer cycle operation OCCUPIED UNOCCUPIED The unit control system will initiate normal occupied mode functions including Morn ing Warm up Economizer Minimum Position and Cooling Cycle whenever a contact closure is made that emulates the normal timeclock contacts See Fig 23 Occupied Unoccupied Switch The contact closure from the BMS must be an iso lated contact set normally open and suitable for 24 volts AC pilot duty NIGHT SETBACK CONTROL Night setback control is used to control the space to a set poi
116. s supplied with 5 vdc power The terminals referenced are shown in Fig 16 Potentiometers P1 and P2 refer to the DLCM potentiometers e 51 IMPORTANT Be careful to avoid damaging the con nector or the processor board when taking the voltage readings Test under the following conditions No power to INI or IN2 Terminal 1 to 2 should read 4 5 vdc 0 1 v Terminal 2 to 3 should read 5 0 vdc 0 1 v Power to IN2 or to both and IN2 and P2 set at 24 Terminal 1 to 2 should read 1 5 vdc 0 1 v NOTE Voltage should vary between 0 5 vdc and 2 5 vdc as the setting of P2 is varied between 0 and 49 Terminal 2 to 3 should read 5 0 vdc 0 1 v Power to INI only and PI set at 50 Terminal 1 to 2 should read 2 5 vdc 0 1 v Terminal 2 to 3 should read 5 0 vdc 0 1 v NOTE Voltage should vary between 0 5 vdc and 2 5 vdc as the setting of P2 is varied between 50 and 100 NOTE If the voltages listed in these 3 tests are not obtained during testing the DLCM board must be replaced Enthalpy Sensor Checkout To test operation of enthalpy sensor see Table 28 Table 28 Enthalpy Sensor Checkout EXPECTED RESULT AND RESPONSE TEST Outdoor air sensor Enthalpy sensor terminal should be connected to terminal on motor Connect the positive terminal of a DC milliammeter to the S terminal of the sensor and the negative terminal of the meter to So terminal of the enthalpy board Indoor air sensor Enthalp
117. set point range of 1 1 to 3 5 in wg and a factory setting of 1 9 in wg To adjust set point turn set point adjusting screw see Fig 39 clockwise to decrease set point and counterclock wise to increase set point This switch also has an adjustable null span The null span is the pressure change that can be made without contacts opening or closing It is adjustable from 0 06 in wg to 0 17 in wg when set point is at mini mum position 1 1 in wg and 0 11 in wg to 0 31 in wg when set point is at maximum position 3 5 in wg To ad just null span turn a null adjusting screw Fig 39 clock wise to decrease span and counterclockwise to increase span All switches leave factory with null span set at maximum position The smaller the null span the closer the pressure will be maintained to desired set point Supply Fan Control with VFD Option The VFD option will modulate Supply Fan motor and thus wheel speed to maintain the static pressure in the ductwork Set point for the VFD option is set at the VFD using the display key board on the front of the VFD enclosure See Fig 40 NOTE The will always provide the proper phase sequence to the supply fan motor The supply fan motor op erates in proper rotation regardless of the phase sequence to the unit If upon start up the outdoor fans operate back wards but the supply fan operates in the correct direction reverse any two leads to the main terminal block All fans wil
118. side of the valid range 40 to 90 F a failure will result Wiring Problem If the circuit is open a failure will be detected Processor Board Failure If the processor board fails hard ware an alarm will be detected 46 CODE 82 LEAVING AIR TEMPERATURE SET POINT POTENTIOMETER FAILURE If leaving air set point po tentiometer P1 located on display board fails control will use a default value A failure will cause an error code of to be displayed on display board when display button is pushed alarm light will also be energized A failure is de termined by establishing a range of 22 F to 70 F as a valid range Anything outside this range will be treated as a fail ure If setting is outside the 22 F to 70 F range alarm light will be energized and an error code of 82 will be displayed when display button is pushed the control will use a set point of 70 F If set point is between 22 and 45 control will use a set point of 45 F and no error code will be indicated If potentiometer returns to normal control will automati cally reset NOTE The full range of the potentiometer is not used for the cooling set point range of 45 F to 70 F The full scale resistance of the potentiometer is 10 Kohms If a failure occurs one of the following is a probable cause Incorrect Potentiometer Setting A potentiometer turned fully clockwise or counterclockwise is outside the valid range and will cause a failure
119. st mode This test will determine if all components are connected and op erating properly 2 If system has been operating and a malfunction occurs check display for diagnostic codes Use diagnostic chart located on inner panel of access door to control box sec tion of unit this chart will help determine probable cause of failure These 2 steps will help determine if a component other than a board is at fault or if the problem is external to control circuit A volt ohmmeter will be needed to troubleshoot boards A digital meter is preferred but a Simpson 260 or equivalent will work A CAUTION To prevent damage to solid state electronic components on boards meter probes should only be placed on ter minals and test points listed in following sections Do not short the electrical components and use extreme care while working on the processor board PROCESSOR BOARD CHECKOUT Refer to Fig 48 and 49 for location of terminal pins and test points Step 1 Check Transformer Input to the Board Connector J4 is used to connect the control transformer to the processor board 1 Set the volt ohmmeter to ac voltage with a range setting of approximately 30 v 2 Turn control switch to ON position 3 Check voltage at following terminals on pin terminal con nector J4 TERMINALS VOLTAGE AC 1to2 15 3 to 20 9 4to6 16 2 to 22 0 5106 8 1 to 11 0 5 to 4 8 1 to 11 0 4 If voltage is not within range check pr
120. t potentiometers P7 and P3 on the reset board Potentiometer P7 Reset temperature set point tempera ture at which reset function will start Maximum of 80 F minimum 0 Set below normal room cooling set point level to sense overcooling in the occupied space NOTE It is difficult to accurately set the P7 potentiometer to the desired set point Use the procedure below Proper setting of the P7 potentiometer may be made on a resistance basis The microprocessor initiates reset when it detects a resistance of the thermistor plus the potentiometer of 13 084 ohm The potentiometer set point may be calcu lated using the following formula P7 13 084 T10p Where P7 the desired set point of the P7 potentiometer in ohms T10 the resistance of the T10 thermistor for the desired set point 850 750 9215 HUN 02 614 mne kil a 1 ie a 23081402 NI d At 0310201 T ge la A a Bo Pan e e Beal eso F BE _ NolidO W3Z1HONO23 _ _ ARO 1V3H MOIN N z E za RE HO 2 8 8 NOLO Q3 A91 ee baee 4 jeeo 4 4 Eb Alle PRATAR cals el an n n TIYA XOB TOULNOJ 2081409 1313 031Y307 OuvOB AV3 1 Lm 1 Lu e n Fa 1 re L3 c wm Le HE HE FE ej HH pH zs
121. t to 12 5 to 13 0 k ohms total resistance Field Connections see Fig 30 Connect fixed resistance with manual potentiometer and variable resistance trans ducer in series Connect wiring to rooftop unit at Size 034 044 TB3 12 and TB3 15 Size 054 104 TB4 12 and TB4 15 20 Configuration Configure as follows 1 Set DIP switch no 2 to ON 2 Adjust manual potentiometer to 12 6 to 12 8 k ohm 3 Configure transducer for job site input signal from BMS 4 Adjust Potentiometer P3 on the rooftop to MAXIMUM SASP value typically 65 to 70 F The maximum P3 SASP control limit is 70 F Operation Unit will initiate SASP Reset adjust config ured SASP upward when the sum of the resistance fixed resistance potentiometer transducer exceeds 13 1 k ohm Once reset is initiated full range of reset P3 setting minus configured SASP will be reached with 500 ohm increase in transducer resistance TR During Reset mode operation Code 21 will appear on unit display board Formula MSP SASP SASP 0 6 F 3 x TR 100 ohm MSP Modified SASP SASP plus Reset TR Resistance at transducer R 13 1 TR required to reach 13 1 k ohm start level DEMAND LIMIT 1 STAGE OR 2 STAGE Both of the Demand Limit functions on the units rely on external switches to initiate the reset functions Contact closures by the BMS can be used in place of these switches Contacts must be isol
122. this installation and use the corresponding VFD set point Hz value If nec essary interpolation between duct static pressure values is permissible 29 ADJUST VFD SET POINT To adjust the VFD set point the VFD must be powered however since it is located near the supply fan and motor operation of the fan and motor is not desirable Either disable the Supply Fan or install the accessory VFD remote display accessory DISABLE SUPPLY FAN MOTOR To disable the supply fan motor and change programming of VFD set point 1 Turn off Indoor Fan Circuit Breaker IFCB This will remove power to the 2 Wait for the VFD display to go blank and remove VFD cover without touching any interior components 3 Ensure that the charge indicator lamp is out which in dicates that the VFD is discharged The lamp is located on the upper right hand corner of the terminal block If still lit wait until lamp goes completely out This may take several minutes 4 Remove jumper from terminals ST CC see Fig 41 and replace VFD cover 5 Turn on IFCB 6 The drive output will now be disabled but the program ming can be changed 7 Change set point according to Table 14 shown below 8 Once the program changes are completed turn off IFCB 9 Wait for the VFD display to go blank and remove VFD cover without touching any interior components 10 Ensure that the charge indicator lamp is out which in dicates that the VFD is d
123. ting null span will be 0 17 in wg while if it is at maximum position the null span will be 0 31 in wg before switch acts If null span is adjusted to a minimum setting duct pressure will vary from 0 06 in wg to 0 11 in wg again depending on switch set point before switch acts Setting null span to minimum position will re sult in a smaller pressure fluctuation than if it is set at maxi mum position Supply Fan Control with VFD When equipped with the VFD option the supply fan static pressure is con trolled by modulating the fan wheel speed The oper ates independently from the microprocessor A duct pressure transducer monitors duct static pressure The transducer out put 4 to 20 mA is directed into the VFD The VFD adjusts supply fan motor speed which changes wheel speed as mea sured duct pressure varies from set point as established at the VFD The VFD will modulate fan speed until the duct pressure set point is achieved NOTE The VFD will always provide the proper phase se quence to the supply fan motor This motor will operate in proper rotation regardless of the phase sequence to the unit If upon start up the outdoor fans operate backwards but the indoor fan operates in the correct direction reverse any two leads to the main terminal block All fans will then operate in the correct direction 38 Modulating Power Exhaust Option or Acces sory except FY JY units The power exhaust as sembly c
124. turn the control ON OFF switch to the OFF position and remove the wiring connec tors connected to pin terminal connectors J5 and J6 Set the meter for resistance If the contacts do not close at the re quired quick test step check the relay outputs from the pro cessor board Relay Board Checkout Fig 5 Step 1 Low voltage relay resistance check 1 Turn switch to OFF position 2 Remove plug connection from terminal strip J6 3 Set meter to measure resistance Connect negative test lead to both terminals 11 and 12 of J6 4 Turn switch to ON position and go into quick test mode 5 Place other meter lead on terminals shown in Table 26 and check resistances at each quick test step 6 If these resistances are not correct and relay board out puts from processor board have been checked out re place relay board Step 2 High voltage relay resistance check 1 Turn switch to OFF position 2 Remove plug connection from terminal connector J5 3 Connect negative test lead to terminal 8 4 Check the resistance between terminals 8 and 5 before entering Quick Test mode The resistance should be infinity Turn switch to ON position and go into Quick Test mode 6 Place other meter lead on terminals shown in Table 27 and check resistance at each quick test step 7 If these resistances are not correct and relay board out puts from processor board have been checked per Pro cessor Board Checkout section on page 48
125. ue of 40 F If setting is between 0 F and 40 F control will use a value of 40 F but no di agnostic code will be displayed if setting is between 80 F and 95 F control will use a value of 80 F but no diagnostic code will be displayed The potentiometer full scale resistance is 10 Kohm but when wired in parallel with other potentiometers on the ac cessory board measured resistance is 3 3 Kohm The failure will automatically reset once potentiometer re turns to normal If a failure occurs one of the following is the probable cause DIP Switch 4 If this switch is in the ON position and the accessory board is not installed accessory board is standard on these units so it should always be on the unit Incorrect Potentiometer Setting If potentiometer is turned fully clockwise or counterclockwise potentiometer will be out of the allowable range resulting in an error Faulty Wiring If the wiring between the potentiometer and the processor board is incorrect an error will occur Potentiometer Failure If potentiometer is shorted or open potentiometer will be out of range resulting in an error Thermistor Troubleshooting The VAV control sys tem uses thermistors to measure temperatures of the enter ing and supply air as well as the saturated condensing tem peratures of the refrigerant circuits The resistance versus temperature and electrical characteristics for all thermistors in the system are identical To obta
126. urn Fig 16 Two Step Demand Limit Module x Fig 18 Variable Frequency Drive Sizes 034 048 and 078 104 END ECONOMIZER HOOD UPPER HOOD ON SIZES 054 104 VARIABLE FREQUENCY DRIVE ENTHALPY SENSOR Fig 17 Enthalpy Sensor Location Fig 19 Variable Frequency Drive Sizes 054 074 12 capacity stages to maintain user established supply air set point temperature When VAV units are also equipped with optional supply duct pressure controls either inlet guide vanes IGV or variable frequency drive package the unit also senses an increase in duct static pressure and responds by closing IGV dampers or slowing fan wheel speed to maintain user configured set points for supply duct pressure Allowing the supply air temperature to be reset to a higher value main tains air circulation in the space without costly overcooling The accessory package is required for temperature reset The accessory includes thermistor T10 to monitor space temperature reset temperature potentiometer P7 to establish start tem perature for reset operation reset limit potentiometer P3 to establish maximum level of modified supply air temperature More than one space sensor may be used if an average space temperature is desired for initiating temperature reset Refer to installation section for sensor part number and wir ing schematic Temperature reset will start when space te
127. utton is pressed during the initialization mode period the unit will run its self diagnostic routine When this is in effect an will ap pear in the display screen Refer to Quick Test Program section below for instructions on completing the Quick Test program Quick Test Program Turn on power to unit IMPORTANT The field supplied switch or time clock must be closed to put unit into the occupied mode The quick test program utilizes the 2 digit LED display see Fig 6 on the set point board to show status of all input and output signals to microprocessor Display action and quick test procedures are described below The quick test program is a 33 step program that provides a means of checking all input and output signals of controls prior to unit start up This check ensures that all control op tions thermistors and control switches are in proper work ing order When unit control circuit is switched to Occupied mode a will appear on the display Immediately press display button once An 88 will appear on the display and alarm light on display board will be energized This indicates that control system is ready to run quick test program IMPORTANT Do not allow unit control circuit to remain energized with showing on display for more than 2 minutes If display button is not pressed within this time period control will attempt to start unit 31 For each step of the 33 step program display button must b
128. witch Inputs CONNECTOR J2 UNIT SIZE TERMINAL NO STATUS SWITCH 034 104 Oil Pressure Oil Pressure e Loss Of Charge Loss of Charge Economizer 13 14 Changeover EC Compressor Fault Compressor Fault 15 24 Signal 1 LEGEND CR Control Relay Enthalpy Control LPS Low Pressure Switch NOTE Terminal numbers 5 6 11 12 16 19 and 21 23 are not used on these units CR1 CR2 LPS1 LPS2 LEGEND CR Control Relay Enthalpy Control LPS Low Pressure Switch Fig 3 Pin Terminal Connector J2 Status Switch Inputs IN2 IN1 LEGEND IN Input Factory Wiring P Potentiometer Field Wiring RNT Return Accessory SW Switch Fig 4 Pin Terminal Connector J3 Potentiometer Inputs The potentiometer locations and functions are as follows PI SUPPLY AIR SET POINT This potentiometer is located on the display board The supply air set point is the cooling mode control temperature which the VAV control system will attempt to maintain at Thermistor 1 by con trol of economizer position and or cycling unloaders and compressors P2 ECONOMIZER POSITION Economizer feedback potentiometer is located on the economizer motor The micro processor is programmed to indicate an alarm if the travel during initialization is less than 10 of the total potentiom eter s resistance An alarm condition will also be signaled if the potent
129. y sensor terminal should be connected to terminal on motor Connect the positive terminal of a DC milliammeter to the S terminal of the sensor and the negative terminal of the meter to Sa terminal of the enthalpy board Milliammeter reading should be between 3 and 24 mA if sensor is operating correctly If reading is 0 mA the sensor is either wired backwards or is defective Milliammeter reading should be between 3 and 24 mA if sensor is operating correctly If reading is 0 mA the sensor is either wired backwards or is defective Economizer Motor All control of the motor i e enthalpy changeover minimum position control and mixed air control is accomplished from the main unit microproces sor through a relay board Service and installation instruc tions for the unit should be consulted to verify proper op eration of these controls The economizer motor may be checked out separately See Fig 52 for VAV economizer motor con nection information Motor Test Apply 24 volt AC power to terminals 1 and T2 of motor Connections to motor terminals 2 and 3 must be disconnected A Motor Test A Expected Result and Response Jumper 1 to Motor drives open if not 2 at motor replace motor B Motor Test B Expected Result and Response Jumper 1 to Motor drives closed if not 3 at motor replace motor LIMIT SWITCHES CAPACITOR WINDING TO ECONOMIZER OPEN MOTOR CCW

Carrier 48FK Air Conditioner User Manual

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