Chiller, Centrifugal, Models PEH/PHH (02/89) - 1076K
Contents
1. 11 PEHO79 Chiller 6 126 Giller scx 3405 06 oes ace 7 MAINTENANCE SCHEDULE 12 13 PHHO63 Chiller 7 McQUAY CENTRIFUGAL OPERATING LOGS Routine Maintenance 8 MicroTech Control Panel 14 Belg a cobs cee wets Rete Wolters 8 Non MicroTech Control Panel 15 Changing Oil Filter 8 Refrigerant 8 McQUAY SERVICE PROGRAMS 16 Electrical System 22 ws os Dek eto 8 INTRODUCTION GENERAL DESCRIPTION The McQuay Centrifugal Water Chillers are com plete self contained automatically controlled water chilling units Each unit is completely assembled and factory tested prior to shipment in the series each unit contains one compressor con nected a condenser and evaporator A sister model called the PHH Heat Recovery Chiller is similar to the PEH models except for the addition of a second split condenser for heat recovery applications The PHH models are equipped with a hot gas bypass system for operation at light cooling loads This hot gas system is standard on PHH units and optional for PEH models The standard chillers use refrigerants 12 and 500 to reduce the size and weight of the package and since they opera2. INSTALLATION AND MAINTENANCE DATA BULLETIN NO IM 307 3 SINGLE COMPRESSOR CENTRIFUGAL CHILLERS 050 063 079 087 100 126 iowa 13600 Industrial Park Blvd P O Box 1551 Minneapolis MN 55440 TABLE OF CONTENTS INTRODUCTION Cleaning and Preserving 8 General Description 2 Seasonal Servicing 8 Oh woes bee 2 Annual Shutdown 8 9 Annual Start up 9 OPERATION Repair of System 9 Operator Responsibilities 3 Pumping DOWN 9 Nomenclature 3 Pressure 9 MicroTech Control Panel 3 Leak TESNO ocd coh eh bodes 9 Capacity Control System 4 EVACUGION BEE 9 10 Vane Operation 4 Refrigeration Charging 10 Metering 4 Pressure Relief Valve Replacement 10 Vane Speed Adjustment 4 5 Equipment Warranty 10 BUI Cu BEEN 5 Evaporator Condenser Flow Limits 10 11 Hot Gas Bypass Gvstem aana aaa anaana 6 Refrigerant
3. Gage Pressure IJL IL th Last o o F fJ eee owens Prese Operating Hours LL LL IL LI NumberofStats ILL T ll ll ll StatHoursAgo Il LL Pese TI UnitRunningOK LJ LL LI Psia II TI Start Up Delta Temp Shut Down Delta Temp Dual unit s only Enable Lag Disable Lag Delay Timer minutes TANVd TOYULNOD 231 6 5201 ZOE WI FULL LOAD DESIGN CONDITIONS CHILLER CONDENSER JOBSNO EE CHILLER PRESS DROP PRESS DROP Compressor F L A LI UNO TEMP _ LVG TEMP Condenser Pump F L A ENT TEMP ENT TEMP Chiter Pump REFRIG TEMP REFRIG TEMP MONTHLY TANVd TOHLNOD HOSLOYOIN NON Ol SHNDIS McQUAY SERVICE PROGRAMS It is important that an air conditioning system receive ade quate maintenance if the full equipment life and full system benefits are to be realized Maintenance should be an ongoing program from the time the system is initially started A full inspection should be made after 3 to 4 weeks of normal operation on a new installation and on a regular basis thereafter McQuay offers a variety of maintenance services through its Nationwide Service Organization and can tailor these services to suit the needs of the building owner Most popular among these serv
4. 4 Solenoid Valve Oil Pressure Differential Switch LEGEND Oil Under Pressure Sump Pressure FLOATING PISTON LINKED TO INLET VANES _ OPENS VANES f CLOSES VANES HOLDING Page 4 IM 307 FOUR WAY SOLENOID VALVE LOCATED IN LUBE BOX PISTON DRAIN 3 OUTLET SECTION SB DE ENERGIZED SECTION SA DE ENERGIZED ADJUSTABLE NEEDLE VALVES FROM OIL WITH FOUR WAY SOLENOID VALVE IGURE 4 VANE CONTROL OPERATION CONTINUED DRAIN FROM PISTON DRAIN FROM PISTON LEGEND Oil Under Pressure QR Sump Pressure 3 OUTLET SECTION SB ENERGIZED SECTION SA DE ENERGIZED 1 INLET FROM OIL PUMP DISCHARGE SECTION SB DE ENERGIZED SECTION SA ENERGIZED FROM OIL PUMP DISCHARGE 1 INLET OIL SYSTEM The oil system for the PEH PHH units provides lubrication and heat removal for the compressor bearings and internal parts In addition the system provides oil under pressure to hydraulically operate the piston for positioning the inlet guide vanes for capacity control Proper operation of the hydraulic system and bearing lubrication system can be assured only if McQuay recom mended oil is used For proper oil selection consult Table 1 Each unit is factory charged with the proper oil Under nor mal operation no additional oil should be needed The oil pump for the CEO50 compressor is completely self contained wit
5. 7537 E1808 3 1612 3 467 1556 2212 1 2216 1 693 2310 3616 5 2384 7948 1808 4 12 4 496 1654 2212 2 2216 2 743 2476 4216 1 2684 8946 1808 5 1812 5 549 1830 2212 3 2216 3 805 2682 42162 2901 9671 2008 1 2012 1 496 1654 2612 1 2616 1 _ 884 2946 42163 ____ 3160 10532 2008 2 E2012 2 555 1850 E2612 2 2616 2 1037 3455 24216 44 3221 10737 2008 3 2012 3 614 2046 2612 3 2616 3 1095 3651 4216 5 3368 11227 2008 4 2012 4 672 2241 2208 1 22121 675 2251 2208 3 2212 3 805 2682 2612 4 2616 4 1169 3896 REFRIGERANT CHARTS TABLE 4 R 12 TABLE 5 R 500 mee E ENE 8 8 8 6 9 9 14 __ 173 9 76 95 1 116 179 0 18 _ 184 2 80 1020 120 1894 42 48 2 82 1056 122 1948 50 5 1 200 2 46 52 8 205 8 88 1167 1 211 5 90 120 6 217 2 2 223 1 229 1 6 123 126 171 4 135 128 _ 176 2 10 146 130 181 0 12 15 8 132 186 0 14 171 134 _ 191 0 16 18 4 136 196 1 18 19 7 113 5 38 201 3 20 206 6 5 92 124 6 54 626 94 1286 1 56 652 96 _ 132 7 58 67 9 98 1369 138 241 4 100 141 2 140 2477 102 1456 142 2452 30 6 104 150 1 4 260 7 AIN 158 258 8 160 265 1 162 271 5 164 278 1 66 79 3 1
6. 3357_ 36165 3471 11569 2208 1 2212 1 640 2134 2212 3 C2216 3 42161 3964 13214 2212 4 2216 4 1133 3778 42162 7 4340 14467 2208 3 2212 3 763 2545 2212 5 2216 5 4216 3 4590 15299 62208 4 2212 4 822 2741 2612 1 26161 1304 4346 42164 4722 15739 2208 5 2212 5 890 2966 2612 2 2616 2 1454 4845 Goes 4842 16140 2612 3 2616 3 1533 5109 4216 6 4936 16454 2208 7 2212 7 1104 3680 2612 4 2616 4 1603 5344 2208 8 2212 8 1169 3896 10 IM 307 TABLE 3 EVAPORATOR FLO KK W LIMITS e 608 1612 1 235 783 216121 267 891 E3012 1 3016 1 1295 4317 1608 2 1612 2 267 891 1612 2 Lasel 1194 E3012 2 E3016 2 1477 4923 1608 3 1612 3 311 1038 1612 3 393 1312 3012 3 016 3 1521 5070 1608 4 1612 4 358 1194 16124 438 1458 E3012 4 016 4 1630 5432 1608 5 1612 5 393 1312 2012 1 2016 1 455 1517 3616 1 1794 5980 1608 6 1612 6 438 1458 3616 2 1985 6617 1808 1 E1812 1 393 1312 2012 3 2016 3 614 2046 3616 3 2202 7341 See 2012 4 2016 4 672 2241 36164 2261
7. KEY O Performed by in house personnel X Performed by McQuay Service personnel IM 307 Page 13 LOE NI OPERATING LOG MICROTECH CONTROL PANEL UNITS Chiller Model No Compressor Each compressor Leaving Chilled Water F Serial No Entering Condenser Water Refrigerant Evap PD Ft 20 Cond PD Ft H20 operating Unit is Running OK Po Low Pressure Unloading a Leaving Evap Temp Max Amp Limit Remote Amp Limit Manual Amp Limit ER ER Unit Running OK Leaving Evap SPT Se ees ee Be ResetLeavingSPT ts ER o eg TI TI ARAE T Condenser Refrig Temp KE Remote Amp Limit in Liquid Line Refrig Temp Remote Amp Signal LI IT __ Liquid Refrig Temp Soft Load Limit ee ln H Cond Approach Temp Beginning Amp Limit ee Pressure PSIG Ramp Up Tire EEE DEE ae Cond Pressure PSIG E EE EE Lift Pressure PSIG Motor Tend tast Fa pe ae Motor Amps OiSumptem E
8. load ELECTRICAL SYSTEM Maintenance of the electrical system involves the general re quirement of keeping contacts clean and connections tight and checking on specific items as follows 1 The compressor current draw should be checked and com pared to nameplate RLA value Normally the actual cur rent will be lower since the nameplate rating represents full load operation Also check all pump and fan motor amperages and compare with nameplate ratings 2 Inspection should verify that the oil heaters are operative The heaters are insert cartridge type and can be checked by ammeter reading They should be energized whenever power is available to the control circuit whenever compressor is inoperative When the com pressor starts the heaters are de energized 3 At least once a quarter all safety controls except com pressor overloads should be made to operate and their operating points checked Any control may shift its operating point as it ages and this must be detected so the controls can be readjusted or replaced Pump in terlocks and flow switches should be checked to assure they interrupt the control circuit when tripped 4 Contactor in the motor starter should be inspected and cleaned quarterly Tighten all terminal connections 5 The compressor motor resistance to ground should be checked and logged semi annually This log will track in sulation deterioration A reading of 5 megohms or less in dicates possible insula
9. will rupture these parts if subjected to freezing temperature FORCED CIRCULATION OF ANTIFREEZE THROUGH THE WATER CIRCUITS IS THE ONLY SURE METHOD OF AVOIDING TROUBLE 2 Take measures to prevent the shutoff valve in the water supply line from being accidentally turned on 3 cooling tower is used and if the water pump will be exposed to freezing temperatures be sure to remove the pump drain plug and leave it out so that any water which may accumulate will drain away 4 Open compressor disconnect switch and remove Fusetrons transformer is used for control voltage the disconnect must remain on to provide power to oil heater Set the manual stop auto switch SWI to the stop posi tion To insure against the possibility of an accidental start remove the fault relay from the left side of the MicroTech panel see Figure 2 page 4 of IM 403 5 Check for corrosion and clean and paint rusted surfaces 6 Clean and flush water tower for all units operating on a water tower Make sure tower blowdown or bleedoff is operating Set up and use a good maintenance program to prevent liming up of both tower and condenser should be recognized that atmospheric air contains many contaminants which increase the need for proper water treatment The use of untreated water may result in cor rosion erosion sliming scaling or algae formation It is recommended the service of a reliable water treatment is required McQuay assu
10. 06 154 7 4 267 4 28 34 2 68 82 3 108 159 4 148 274 2 30 70 85 4 110 154 1 gt IM 307 Page 11 MAINTENANCE SCHEDULE FIGURE 8 MAINTENANCE INTERVAL 1 COMPRESSOR A Performance Evaluation Log Condit amp Analysis B Motor Meg Windings Ampere Balance within 10 Terminal Check tight conn porcelan clean Motor Cooling check temperatures Lubrication System Oil Lines Temperatures Water Refrigerant Coolant Temperature Oil Cooler Strainer water Oil Cooler Solenoid Operation Analysis Oil Appearance clear color quantity Oil Filter Change D Vane Operation Compressor Loads Operate Manual Switch Record Motor Amps Compressor Unloads Operate Manual Switch Record Motor Amps Vanes Will Hold place manual switch in hold Observe Water Temp amp Record Amps E Internal Compressor Check H CONTROLS A Operating Controls Check LRT Settings and Operation Check Vane Control Setting and Operation Verify Motor Load Limit Control Verify Load Balance Operation Check Oil Pump Contactor B Protective Controls Test Operation of Alarm Relay Pump Interlocks Hot and Oil Temperature Switches Guardistor and Surgeguard Relays High and Low Pressure Switches High Suction Temperature Switches High Discharge Temperature Switch Low Pressure Override Switch Oil Pump Pressure Differential Switch Oil Pump Safety Timer
11. Oil Pump Time Delay Switch System Monitor Timer Ee F GE Vane Closed Switch ie ee ees ee des A Performance Evaluation B Test Water Quality eee Clean Condenser Tubes I E Test Tube Wall Thickness E Seasonal Protection KEY O Performed by in house personnel X Performed by McQuay Service personnel Page 12 IM 307 FIGURE 8 MAINTENANCE INTERVAL Continued IV EVAPORATOR A Performance Evaluation Log Condit amp Analysis C Clean Evaporator Tubes as required D Eddycurrent Test Tube Wall Thickness as required Seasonal Protection V EXPANSION VALVES A Performance Evaluation Superheat Control COMPRESSOR CHILLER UNIT A Performance Evaluation B Leak Test Compressor Fittings and Terminal Piping Fittings Oil Pump Joints and Fittings Vessel Relief Valves C Vibration Isolation Test D General Appearance Paint Insulation Vil STARTER S A Examine Contactors hardware and operation B Verify Overload Setting and Trip C Test Electrical Connections D Pump Down Control verify operation Vill OPTIONAL CONTROLS A Hot Gas Bypass Controls verify operation B Liquid injection Controls verify operation C Pump Down Control verify operation
12. d safely by introducing the liquid refrigerant directly into the bottom of the evaporator with the expansion valve manually opened Both condenser water and chilled water must be flowing through the respec tive vessels to prevent localized freezing Consult the chiller nameplate for the proper refrigerant charge With a near normal charge in the system final charging can best be accomplished with the unit running with the com pressor at full load In this operating mode the unit should be charged until suction superheat is between 2 and 6 F adjusting the thermal expansion valve as necessary Con tinue charging until 9 to 11 F liquid subcooling is obtained leaving the condenser if the unit is operating at full load At less than full load liquid subcooling will be proportionally less PRESSURE RELIEF VALVE REPLACEMENT Current condenser designs use two relief valves 1 separated by a three way shutoff valve In the event one of the relief valves is leaking on the two valve set the following procedures should be followed If the valve closest to the valve stem is leaking back seat the three way valve all the way closing the port to the leak ing pressure relief valve Remove and replace the faulty relief valve The three way shutoff valve should remain either fully back seated or fully forward for normal operation If the relief valve furthest from the valve stem is leaking front seat the three way valve and replace the reli
13. e from other compressor cavaties Remove the filter replace with new element and replace filter cover using new gasket Reopen valve in pump discharge line When the machine is operated again the oil level should be checked to determine if oil needs to be added to main tain proper operating level CAUTION Improper servicing of the lubrication system including the addition of excessive or incorrect oil substitute quality oil filter or mishandling of the equipment under pressure is hazardous Only authorized and trained ser vice personnel should attempt this service For qualified assistance contact your local McQuay Service technician REFRIGERANT CYCLE Maintenance of the refrigerant cycle consists of maintaining a log of the operating conditions and assuring the unit has the proper oil and refrigerant charge See the maintenance schedule and the appropriate operating log at the end of this bulletin At every inspection the oil suction and discharge pressures should be noted and recorded as well as con denser and chiller water temperatures The suction line temperature at the compressor should be taken at least once a month Subtracting from this the saturated temperature equivalent of the suction pressure will give the superheat Extreme changes in superheat over a period of time will indicate losses of refrigerant or possible deterioration of the expansion valves Proper superheat ting is 2 to 6 at full
14. e in material or workmanship Specific details of this warranty can be found in the warranty state ment furnished with the equipment Page 2 IM 307 In the application of cooling towers with McQuay model PEH centrifugal chillers the towers are normally selected for maximum condenser inlet water temperature on the order of 85 F Lower entering water temperature may be desirable from the standpoint of energy performance but a minimum does exist For recommendations for optimum entering water temperature and cooling tower fan control consult McQuay Catalog 950 Applications Section The operating and maintenance procedures for the PEH and PHH chillers are identical in most respects therefore all references made in this manual for the PEH chillers will equally apply to the PHH models unless specifically noted For simplicity only the PEH designation will be used w OPERATION OPERATOR RESPONSIBILITIES It is important that the operator become familiar with the equipment and the system before attempting to operate the chiller In addition to reading this manual the operator should study installation and operation bulletin IM 403 and the control diagram furnished with the unit so that he understands the Starting operating and shutdown sequences as well as the safety shutdown modes When the McQuay Service technician performs the initial startup of the chiller he will be available to answer any ques tions and to instruct in pr
15. ef valve and replace the relief valve as stated above EQUIPMENT WARRANTY Each PEH PHH centrifugal chiller manufactured by McQuay carries a standard limited warranty This warranty covers repair or replacement of component parts which prove defec tive in material or workmanship within 12 months from initial startup or 18 months from date shipped by the company whichever comes first For a complete description of this warranty refer to the war ranty form furnished with the equipment EVAPORATOR amp CONDENSER FLOW LIMITS TABLE 2 CONDENSER FLOW LIMITS C1608 1 C1612 1 2612 5 2616 5 T 385 1282 1608 2 1612 2 300 996 1612 2 1608 3 1612 3 1612 3 _ 505 1684 3012 2 C3016 2 1608 4 1612 4 402 1341 1624 549 1830 3012 3 3016 3 2073 6910 1608 5 1612 5 482 1605 1612 5 576 1918 1608 6 1612 6 529 1762 3012 5 3016 5 2226 7419 1812 2 1816 2 623 2075 1808 1 1812 1 452 1507_ 1812 3 18163 672 2241 3662 3180 10600 1808 2 1812 2 496 1654 _ 1812 4 1816 4 699 2330 3616 3 3274 10914 048 62212 2216 1 819 2731 3616 4 3394 11315 050 1808 4 1812 4 649 2163 2212 2 2216 2 1007
16. efer to the following para graphs The evacuation procedure can be followed in both cases LEAK TESTING In case of the loss of the entire refrigerant charge the unit should be checked for leaks prior to charging the complete system This can be done by charging only enough refrigerant into the system to build the pressure up to approximately 10 psig and adding sufficient dry nitrogen to bring the pressure up to a maximum of 125 psig and then leak test with Halide or electronic leak detector CAUTION DO NOT USE OXY GEN TO BUILD UP PRESSURE AS A SERIOUS EXPLO SION CAN RESULT A pressure regulating valve should always be used on the drum being used to build the system pressure Also do not exceed the test pressure given above When the test pressure is reached disconnect the gas cylinder H any leaks are found in welded or silver soldered joints or if it is necessary to replace a gasket relieve the test pressure in the system before proceeding For copper joints silver solder is recommended After making any necessary repair the system should be evacuated as described below EVACUATION After it has been determined that there are no refrigerant leaks the system should be evacuated using a vacuum pump with a capacity of approximately 3 cu ft min and that will reduce the vacuum to at least 1 millimeter 1000 microns A mercury manometer electronic or other type of micron gauge should be connected at the farthest point from the
17. ent occurs in response to oil flow from the SA or SB solenoid valve which in turn respond to a control module signal This oil flow activates a piston to rotate the vanes VANE OPERATION The hydraulic system for the vane control operation consists of a 4 way normally open solenoid valve Oil under pressure is directed by the 4 way valve to either or both sides of the piston depending on whether the control signal is to load unload or hold To open the vanes or load the compressor solenoid SA is de energized and solenoid SB is energized allowing oil flow from port SA to one side of the piston to then drain through port SB To close the vanes unload compressor valve SB is de energized and valve SA is energized to move the piston and vanes to unload position When both solenoid valves SA and SB are de energized full oil pressure is directed to both sides of the piston through ports SA and SB thus the vanes are held in that position Refer to Figure 3 for solenoid action Note that both solenoids cannot be energized simultaneously METERING VALVES The speed at which the capacity control vanes are opened or closed can be adjusted to suit system operating re quirements Adjustable needle valves in the oil drain lines are used to control the rate of bleed off and consequently the vane speed These needle valves are part of the 4 way solenoid valve assembly located in the compressor lube box Figure 2 The valves a
18. erature and prevents the unit from star ting with low oil temperature This prevents refrigerant laden oil from being delivered to the bearings upon start up For details see page 24 of Installation amp Maintenance Bulletin IM 403 or the MicroTech control panel The compresssor is equipped with lubrication protection for coast down in the event of a power failure This is ac complished by the use of a spring loaded piston in models CEO50 thru 100 When the oil pump is started the piston is forced back by oil pressure compressing the spring and fill ing the piston cavity with oil When the pump stops the spring pressure on the piston forces the oil out to the bearings In model CE126 the compressor coast down lubrication is supplied from a gravity feed lube reservoir SUNISO 4GS SUNISO 5GS WF68 WEI 00 CE100 11 0 SUNISO 5GS TEXACO REGAL 150 CE126 12 0 TEXACO WF100 SHELL TURBO 150 IM 307 Page 5 HOTGAS BYPASS The PHH heat recovery chillers are equipped with a hot gas bypass system used to feed discharge gas directly into the evaporator when the system load falls below 10 of the com pressor capacity Light load conditions are signaled by measurement of a set percentage of RLA amps by the MicroTech control panel When the RLA drops to the hot gas setpoint the hot gas FIGURE 5 PEHO79 CHILLER REAR VIEW 1 Evaporator Pressure Relief Valve 2 Chilled Water Connections 3 Oil Cooler Water Co
19. hin the compressor housing The assembly in cludes the pump pump motor oil heater and oil separator The oil is pumped through the oil discharge line to the oil filter in the compressor casting and then to the refrigerant cooled oil cooler The other compressor sizes CE063 079 087 100 and 126 utilize a separate oil pump contained in its own oil reser voir This assembly includes pump motor heater and oil separator Oil is pumped through the discharge line through the external oil cooler and then to the oil filter inside the com pressor housing Standard PEH PHH 063 126 units utilize a water cooled oil cooler although an optional refrigerant cooled oil cooler is available The oil coolers serve to maintain the proper oil temperature under normal operating conditions The coolant flow control valve should maintain 90 F 100 F oil temperature leaving the oil cooler for optimum operation of the oil system Bearings are supplied with oil through internally drilled passages within the compressor assembly The oil drains from the bearings into the gear housing and is gravity returned to the oil sump The oil heaters in the gear case and in the oil pump reser voir must remain energized whenever the compressor is off IN THE EVENT OF POWER LOSS TO THE HEATERS ALLOWING THE OIL TO COOL THE HEATERS SHOULD BE ENERGIZED FOR 24 HOURS PRIOR TO STARTING THE COMPRESSOR The MicroTech Microprocessor based control panel monitors the oil temp
20. ices is the McQuay Com prehensive Maintenance Plan wherein McQuay assumes full responsibility for your air conditioning equipment cluded are regular routine inspections and emergency ser vice by factory trained technicians All parts labor materials and refrigerant are included ina McQuay Com prehensive Maintenance Contract For further information concerning the many services available contact your local McQuay Service representa tive
21. mes no responsibility for the results of untreated or improperly treated water 7 Remove condenser heads at least once a year and clean condenser tubes ANNUAL STARTUP A dangerous condition can exist if power is applied to a faul ty compressor motor starter which has been burned out This condition can exist without the knowledge of the person start ing the equipment This is a good time to check all the motor winding resistance to ground Semi annual checking and recording of this resistance will provide a record of any deterioration of the winding insulation All new units have well over 100 megohms resistance between any motor terminal and ground Whenever great discrepancies in readings occur or uniform readings of less than 5 megohms are obtained the motor cover should be removed for inspection of the winding prior to starting the unit Uniform readings of less than 5 megohms indicate motor failure is imminent and motor should be re placed or repaired Repair before failure occurs can save a great deal of time and labor expended in the cleanup of a system after motor burnout 1 The control circuit should be energized at all times If the control circuit has been off and oil is cool energize oil heaters and allow 24 hours for heater to remove refrigerant from the oil before starting 2 Check and tighten all electrical connections 3 Replace the drain plug in cooling tower pump if it was removed at shutdown time the previo
22. model style and serial numbers and includes the electrical characteristics of the compressor motor The 50 com pressor nameplate also shows the oil pump electrical characteristics The condenser and evaporator vessels have nameplates Stamped with the maximum working pressure of the vessel It should be noted that the vessel relief valve maximum set tings coincide with the maximum refrigerant side vessel work ing pressure NOMENCLATURE CHANGE The letter has been added behind the first two digits of the model code to signify a hermetic compressor motor Models PE and PH are synonymous with PEH and PHH respectively MICROTECH CONTROL PANEL The MicroTech Unit Controller is a microprocessor based con trol panel designed to initiate the step by step start functions of its host centrifugal compressor unit monitor and regulate the capacity protect it and sequence the com pressor shutdown on temperature demand or in response to FIGURE 1 MICROTECH CONTROL PANEL a pre set time For full information on the features installation operation and problem analysis of the McQuay Microprocessor control for Centrifugal chillers see Installation and Operation Manual IM 403 IM 307 Page 3 CAPACITY CONTROL SYSTEM The compressor capacity is controlled by the movement of the inlet vanes opening or closing to permit the correct quan tity of refrigerant to enter the wheel or impeller The vane movem
23. nnections 4 Condenser Pressure Relief Valve 5 Oil Cooler Page 6 IM 307 bypass solenoid is energized leaving hot gas bypass available for use This introduction of hot gas provides a stable refrigerant flow and keeps the machine from short cycling under light load conditions It also prevents surge during heat recovery operation The factory setpoint for bringing on hot gas bypass is 40 of RLA See IM 403 page 33 for details Q LEGEND 6 Oil Pump Assembly 7 Discharge Line Check Valve 8 Lube Control Box 9 Motor Cooling Feed Line 10 Compressor Motor Terminal Box FIGURE 6 PEH126 CHILLER 1 63 Compressor 2 Spin Down Reservoir 3 MicroTech Control Panel FIGURE 7 6 CHILLER REAR VIEW P 9 CE063 Compressor Oil Pump Oil Cooler Discharge Check Valve Discharge Check Evaporator LEGEND 4 Evaporator Relief Vaive 5 Condenser Relief Valve 6 Liquid Line Shutoff Valve EN 2 N 4 5 o LEGEND Rejection Condenser Heat Recovery Condenser Condenser Relief Valves 10 Motor Terminal Cover 12 Evaporator Relief Valve Oil Filter 10 Condenser 11 Evaporator 9 Filter Drier 13 Lube Box 14 Control Panel 15 Motor Cooling Liquid Line 16 Expansion Valve 17 Compressor Suction Line IM 307 Page 7 MAINTENANCE ROUTINE MAINTENANCE LUBRICATION See CAUTION After the s
24. oper operating procedures It is recommended that the operator maintain an operating log for each individual chiller unit A suggested log sheet is shown on pages 14 and 15 of this manual In addition a separate maintenance log should be kept of the periodic maintenance and servicing activities This McQuay centrifugal chiller represents a substantial investment and deserves the attention and care normally given to keep this equipment in good working order If the operator should encounter abnormal or unusual operating conditions it is recommended that a McQuay Service techni cian be consulted McQuay conducts training for centrifugal operators at its factory Training Center several times a year These sessions are structured to provide basic classroom instruction and in clude hands on operating and troubleshooting exercises For further information contact your McQuay representative NOMENCLATURE Each centrifugal chiller is assigned a set of identifying numbers which are used to describe the unit features and to identify each individual unit These four number groups are stamped on each unit nameplate A typical nameplate is shown in Figure 1 All inquiries pertaining to operating and servicing of this unit should include all identification numbers Each of the individual components also have nameplates to provide certain necessary information to the installer and the operator The compressor nameplate identifies the compressor
25. re normally factory set so the vanes will move from fully closed to fully open in approximately 3 minutes and from fully open to fully closed in 1 minute except CE126 The speed should be slow enough to prevent over controlling and hunting FIGURE 3 VANE CONTROL SOLENOID OPERATION COMPRESSOR UNLOADER CYLINDER VANE SPEED ADJUSTMENT The vane speed at which the capacity control vanes open or close is controlled by the rate of oil bleed off from the vane actuating piston This bleed off rate is adjustable by position ing the needle valves on SA and SB solenoid valves located in the lube box Screwdriver openings in the left side of the lube box per mit access The upper opening accesses the SB needle valve for adjusting the vane OPENING speed for loading the com pressor refer to Figure 2 Turn this screw clockwise to decrease the vane opening speed and counterclockwise to increase the opening speed The lower opening accesses the SA needle valve for ad justing the CLOSING speed for unloading the compressor The same adjustment applies clockwise to decrease clos ing counterclockwise to increase vane closing The vanes are factory set so that from fully closed to fully open positioning of the vanes requires about 3 minutes and about 1 minute from fully open to fully closed Exception CE126 settings are 9 minutes to open and 3 minutes to close FIGURE 2 LUBE BOX Vane Speed Adjustment Opening 3 Closing
26. te at a positive pressure over the entire operation range no purge system is required The controls are completely prewired adjusted and tested Only normal field connections such as piping electrical and pump interlocks etc are required thereby simplifying installa tion and increasing reliablility All necessary safety and operating controls are factory installed in the control panel The six basic sizes of units are the 063 079 087 100 and 126 and provide a capacity range from 80 tons to 1200 tons The is also applied with modified im pellers and are designed as 46 or 4 In this manual all references to the models will equally apply to PHH models unless specifically referenced otherwise APPLICATION The operation and maintenance procedures presented in this manual apply to the standard model PEH chillers and the model PHH heat recovery chillers Reference to the Installa tion Manual IM 306 and the MicroTech Operation Manual IM 403 for these units should be made for details pertaining to receiving and handling installation piping and wiring and preparation for initial startup All McQuay centrifugal chillers are factory tested prior to shipment and must be initially started by a factory trained McQuay Service technician Failure to follow this startup pro cedure may affect the equipment warranty The standard warranty on this equipment covers parts which prove defectiv
27. tion failure and should be further checked 6 The centrifugal compressor must rotate in the direction indicated by the arrow on the casting near the rotation sightglass If the operator has any reason to suspect that the power system connections may have been altered the compressor should be jogged to check rotation For assistance call McQuay Service CLEANING AND PRESERVING A common cause of service calls and equipment malfunc tion is dirt This can be prevented with normal maintenance The system components most subject to dirt are 1 Permanent or cleanable filters in the air handling equip ment must be washed in accordance with the manufac turer s instructions throwaway filters should be replaced The frequency of this service will vary with each installation 2 Remove and clean strainers in chilled water system cooler line and condenser water system at every inspection SEASONAL SERVICING Prior to shutdown periods and before starting again the following service procedures should be completed ANNUAL SHUTDOWN 1 Where freezing temperatures may be encountered the 8 307 condenser and chiller water piping should be disconnected from the supply and drained of all water Dry air blown through the condenser will aid in forcing all water out Removal of condenser heads is also recommended The condenser and evaporator are not self draining Water mitted to remain in the piping and vessels
28. us season 4 Install Fusetrons in main disconnect switch if removed 5 Reconnect water lines and turn on supply water Flush out condenser and check for leaks 6 Refer to Service Manual 5 001 Centrifugal System Checkout amp Start up information and IM 403 before energizing the compressor circuit REPAIR OF SYSTEM PUMPING DOWN If it becomes necessary to pump the system down extreme care should be used to avoid damage to the water chiller due to freezing Always make sure that full water flow is main tained through the chiller while pumping down To pump system down close all liquid line valves With all liquid line valves closed and water flowing through chiller start the com pressor Set the MicroTech panel to the manual load see IM 403 The vanes must be open while pumping down to avoid a surge or other damaging condition Pump the unit down until the mechanical low pressure switch MLP cuts out at 25 psig Use a portable condensing unit to complete the pump down condensate the refrigerant and pump it into the condenser PRESSURE TESTING No pressure testing is necessary unless some damage was incurred After repairs are made pressure test the system at a pressure that does not exceed the standby pressure in the condenser A test pressure higher than condenser pressure would open the discharge check valve and allow flow of test pressure into condenser In cases where the en tire refrigerant charge is lost r
29. vacuum pump For readings below 1 millimeter the electronic or other micron gauge should be used The triple evacuation method is recommended and is par ticularly helpful if the vacuum pump is unable to obtain the desired millimeter of vacuum The system is first evacuated to approximately 29 inches of mercury Enough refrigerant vapor is then added to the system to bring the pressure up to zero gauge pressure Then the system is once again evacuated to approximately 29 inches of mercury This is IM 307 Page 9 repeated 3 times The second pull down will remove about 90 of that remaining from the first pull down and after the third only 1110 of 1 non condensables will remain REFRIGERANT CHARGING The McQuay centrifugal chillers normally use 2 or 500 refrigerant therefore it is recommended that the operator check the unit nameplate to assure the correct refrigerant selection prior to charging or adding refrigerant An initial operating charge is made at the factory prior to shipment In the event the operator needs to add refrigerant after the unit is installed certain precautions should be taken to protect equipment components Refrigerant charging lines must be kept dry clean and free of non condensable gases Care should be taken in selecting the best charging point in the unit so as to protect the equipment from damage If the entire charge is lost or removed from the unit recharg ing can be accomplished quickly an
30. ystem is once placed into operation no other ad ditional oil is required except in the event that repair work becomes necessary to the oil pump or unless a large amount of oil is lost from the system due to a leak If oil must be added with the system under pressure use a hand pump with its discharge line connected to the ser vice valve at the bottom of the oil pump The 50 com pressor with its internal oil pump is equipped with an oil ser vice valve on the compressor CHANGING OIL FILTERS See CAUTION 50 Compressors lf the unit is equipped with a suction line service valve close this valve and close the valve on the motor cooling liquid line to isolate the compressor Vent the refrigerant pressure from the compressor Remove the filter cover and the old filter and install the new filter open end first Replace the cover using a new gasket Reopen the suc tion and liquid line valves If the unit is not equipped with a suction line service valve the unit will have to be pumped down in order to remove the pressure in the compressor before removing the cover and changing the filter Refer to later section for pumpdown procedure CEO63 and Larger Compressors The oil filter in each of these machines can be changed by simply isolating the filter cavities Close the oil discharge line service valve at the oil pump at the filter on CE126 Remove the filter cover some foaming may occur but the check valve should limit leakag
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