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Bus Air Conditioning Unit - North America Transport Air Conditioning

1. Thermostatic Expansion Valve TXV Electrical Control Panel See figure 1 3 Air Filter Liquid Line Evaporator Coil Ui QO N Figure 1 2 Unit Assembly Inside View 1 3 Revised 10 9 96 O tO 4 OY U1 P CJ NJ N Circuit Breaker Circuit Breaker Circuit Breaker Circuit Breaker Circuit Breaker Circuit Breaker Relay Board Heat Relay No 2 HR2 Temperature Selector Air Conditioning Relay ACR Reheat External source 78 9 1011121314 16 E RB i L e el ESR ios E af cari J M 53 b H Li
2. 09 GR 2 S omn Lo So z z 253333 zas as m m SSES GRN r O CONNECTION WH BL ORG 2 LOAD OF LS 05 ERN O No CONNECTION UNLOAD O WH BL C y ORG MI so E i M HIGH L8 08 OPEN P RISE 360410 CLOSE P DROP 285415 TAS HEAT 2 L1 01 C4 Ha Hj COOL L3 03 2 BAIN 39 SCH at gt G 67 S 1 LOW AMBIANT FRE SWITCH 84545 013 FREEZEO CLOSE 055 5 ELECTRONIC THERMOSTAT TH 12 Energized Circuit 02 Ti De energized Circuit Figure 2 7 Automatic Low Speed Heat 2 7 POWER TERMINAL BLOCK PTBI 15A 102 CH T4 TO DEFROST lt Dj TS TI MANUAL RESET CIRCUIT BREAKER CB2 40A ID 6 TI MANUAL RESET CIRCUIT BREAKER CB3 40A 2 O TI MANUAL RESET CIRCUIT BREAKER 5 60A 1 n 2 Ri K BLACK poi GRD GRD GRD GRD TI MANUAL RESET CIRCUIT BREAKER 4 604 1 02 O NOTE 3 RED c BLACK 2 RED BLACK v GRD MAIN POWER TERMINAL 24V DC 24 VOLTS TI MANUAL RESET CIRCUIT BREAKER 10 O CR FR ACSRI
3. AUTOO e ui GRD COLI COOL O 69 5 9 COM VENTO 3 4 HEATO 4 IRC OPEN P RISE 360 10 KOR CLOSE P DROP 285 15 GRD 68 6 OAUTO lt mre 3 4 L OREHEAT GRD OcooL LATH OVENT COM LOW AMBIANT We CONTRO OPEN 04545 CLOSE 055 5 CACMS Figure 5 2 Electrical Schematic Wiring Diagram 5 M ode Selector Switch Dwg No 68RM 35 1038 Rev A Sheet 2 of 2 5 5 PTB2 PTB2 PTB2 PTB2 PTB2 CEFR14 CCFR24 CFR14 SYMBOL DESCR GEND PTION ACHM ACS ACSRI ACSR2 BPR CBI CB2 CB3 CB4 CBS CBE FS lt C C C C Z r x TI rTi ri OO O O CH NOTES 1 UNIT SHOWN IS IN T 2 RELAY CONTACTS SHO 3 ADDRESS 5 5 EXA COND FAN RELAY 2 4 WIRE IDENTIFICATIO COLORS WHITE D GREEN 6 YELLOW O A C HO A C SW A C 51 A C SI BOOST 15A CIRCUI 35A CIRCUI 35A CIRCUI 70A CIRCUI 70A CIRCUI 10A CIRCUI CONDENSER CLUTCH CONDENSER CONDENSER CLUTCH RE DIODE 1 DEFROST S ENGINE CO EVAPORATO EVAPORATO FAULT REL HIGH LOW AMBIE LOW PRESS POWER TER REHEAT CO ELECTRONI UNLOADER UNLOADER UNLOADER PRESSURE SWITCH 3 UNLOADER VALVE 1 UNLOADER VALVE 2 WATER PUM NDICA NDICA NDICA NDICA NDICA NDICA NDICA
4. 48 Adding Refrigerant To System 49 Checking the Refrigerant 410 Filter Drier Removal 411 Checking Pressure Switches 4 12 Thermostatic Expansion Valve 2 4 13 Removingthe Heater Col Page 1 1 11 1 5 1 6 1 6 17 1 9 1 9 1 9 2 1 2 1 2 1 2 1 2 1 2 2 2 3 2 4 2 4 3 1 3 1 3 1 3 1 3 2 3 2 3 2 3 2 3 2 3 2 3 3 4 1 4 1 4 1 4 2 4 2 4 2 4 3 4 3 4 5 4 5 4 5 4 6 4 7 4 8 TABLE OF CONTENTS CONT D Section 4 SERVICE CONT D rire 4 14 Servicing the Reheat Coolant Valve 4 15 Removing Condenser Fan 4 16 Servicing the Evaporator Fan Blower M otor 4 16 1 Routine Examination and 0 416 2 Brush Replacement 4 17 Replacing the Return Air Filters 4 18 056 Compressor Maintenance 4 18 1 Replacing the compressor 4 18 2 Checking the Compressor Oil Level 4 18 3 Adding Oil to the Install
5. 4 2 Gauge Manifold Set c eine bu Ri CURE ui 4 3 Evacuation M ariltold wa ee Rer ete AME s 4 4 vac ation Setip oe ost Der au eet nt eR S Gem rs eed Pen 4 5 Filter Drier Rue CT 4 6 Checking High Pressure Switch 4 7 Thermostatic Expansion Valve 4 8 Thermostatic Expansion Valve Bulb and Thermocouple 4 9 Reheat Coolant Valve Assembly 4 10 Condenser Fan 4 11 Evaporator Fan Blower 4 12 Compressor Oil Charge Connection 4 13 Compressor Model 05G Page 4 1 4 8 4 9 4 9 4 10 4 10 4 10 4 11 4 11 4 11 4 11 4 12 5 1 5 1 1 2 13 1 4 1 5 1 9 1 9 2 1 2 2 2 3 2 4 2 4 2 6 2 7 2 8 LIST OF ILLUSTRATIONS CONT D Figure Page 5 1 Electrical Schematic Wiring Diagram 4 M ode Selector Switch amp Rotron Motors 5 2 5 2 Electrical Schematic Wiring Diagram 5 M ode Selector Switch 5 4 5 3 Electrical Schematic Wiring Diagram Automatic Operation amp Rotron Motors 5 6 5 4 Electrical Schematic Wiring Diagram Non Relay Board 22 Pin Connector 5 8 5 5 Electrical Schematic Wiring Diagram Non Relay Board Terminal Strip Connect
6. H UPS1 GRD OPEN P RISE 360510 CLOSE P DROP 285415 TEMPERATURE lt ie gt gt Loo E CFS 3 GRD CFR14 gw AUTO ORI 2 L 30 30 e gt E er SE dj GRD TC10 REHEAT b Qum po 3 COOL O D3 4 SE ENTO 7 cosi GRD TCS 6 o TE E GC E 54 3 GRD CFR24 4 6 8 Lear 10 3 4 1 5 GRD FR14 7 O coo coo p COM Tato fret 85 86 GRD BPRBE pe LOM AMBIANT ee Ver p 055 CTH TC10 TAB NOTE TA TERMINAL BLOCK A TO DRIVERS DASH TB TERMINAL BLOCK ENGINE COMPARTMENT TC TERMINAL BLOCK CON CONTROL PANEL Figure 5 5 Electrical Schematic Wiring Diagram Non Relay Board Terminal Strip Connections D wg No 68R 35 1114 3 Rev Sheet 2 of 2 5 11 POWER TERMINAL BLOCK CB1 15 PIBI 3 BPR rBg due TI MANUAL RESET 30 87 Al CIRCUIT BREAKER GRD ESR 01 EL
7. e 9 ges rar 24 5 21 Jo 19 18 UNITS WITH GENERAL ELECTRIC MOTORS 7 8 9 1011 13 15 16 NE 7 i ds Ce h ESR o L du PUR CR cl ba Gi ACSRI ih CB6 CB5 CB4 CB3 CB2 CBI 10 Amp 60 Amp 60 Amp 40 Amp 40 Amp 15 Amp Leed a ER YS 5 4 Receptacle Overload Relay No 2 OR2 23 22212019 18 UNITS WITH ROTRON MOTORS 13 14 15 16 17 18 19 20 Cycle Clutch Receptacle CB Not Used Evaporator Overload Relay No 1 OR1 Electronic Thermostat Terminal Block Evaporator Speed Relay ESR Air Conditioning Stop Relay No 2 ACSR2 Heat Relay HR Air Conditioning Stop Relay No 1 ACSR1 Figure 1 3 Electrical Control Panel 1 4 21 23 24 25 27 28 Clutch Relay CR Fault Relay FR Booster Pump Relay BPR Condenser Speed Relay No 1 CSR1 Condenser Fan Relay No 1 CFR1 Condenser Fan Relay No 2 CFR2 Evaporator Fan Relay No 1 EFR1 Evaporator Fan Relay No 2 EFR2 1 056 Compressor 2 Clutch 3 High Pressure Swjtch 4 Low Pressrow gi 12 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS Refrigeration Charge R 22 or R 134a 16 to 17 Ib 7 3 to 7 7 kg Compressor M odel 05G No of Cylinder 6 Weight Dry 145 105 66 kg including clutch Oil L evel Oil Charg
8. NN lt I gt pl lt 1 Expansion Valve Suction Service Port 15 16 17 Gauge Compound Gauge Vacuum Pump Refrigerant Cylinder 1 Condenser Coil 9 Discharge Service 2 Filter Drier Outlet Valve Service Valve 10 Suction Service 3 Filter Drier Valve 4 Filter Drier Inlet 11 Compressor Service Valve 12 Reclaimer 5 Receiver 13 Vacuum Manifold 6 Thermostatic 14 Thermistor Vacuum 7 8 Discharge Service Port Figure 4 4 Evacuation Set Up 4 8 ADDING REFRIGERANT TO SYSTEM a Installing a Full Charge a Install a manifold gauge set as outlined in section b Evacuate and dehydrate the system as outlined in section 4 7 if not completed at thistime Placethe appropriate refrigerant cylinder R 22 134a on the scale and connect charging line from the cylinder to the filter drier inlet valve Purge charging line at valve d Note weight of refrigerant cylinder e Open liquid valve on refrigerant cylinder Open filter drier inlet valve half way and allow the liquid refrigerant to flow into the unit Monitor weight of refrigerant cylinder to determine how much refrigerant is entering the system The correct charge is 17 Ibs f When refrigerant cylinder weight scale indicates that the correct charge has been added close liquid line valve at the cylinder and
9. PRES URMETER OPTIONAL ITCH COFF ON OP RELAY 1 OP RELAY 2 PUMP RELAY T BREAKER WATER PUMP RELAY REAKER EVAP MOTOR 2 REAKER EVAP MOTOR 1 AND 2 R B R B R T BREAKER COND MOTOR 1 B R R D T BREAKER COND MOTOR 2 T BREAKER CLUTCH FAN SPEED SWITCH 360 PSI FAN MOTOR 1 FAN MOTOR 2 AY DIODE 27 ITCH OPTIONAL LANT SWITCH COPTIONAL FAN MOTOR 1 FAN MOTOR 2 lt URE SWITCH T THERMOSTAT OPTIONAL RE SWITCH INAL BLOCK LANT VALVE THERMOSTAT RESSURE SWITCH RESSURE SWITCH 2 P RELAY NDICATES RELAY BOARD CONNECTION ES A WIRE GROUND ES CUSTOMER SUPPLIED COMPONENTS amp WIRING ES CONNECTION LUG SCREW ETC ES A CONNECTOR ES A NORMALLY OPEN CONTACT ES A NORMALLY CLOSED CONTACT ES BUS INTERFACE CONNECTOR PIN LOCATION ES RELAY BOARD TRACE 22 PIN CONNECTOR HE 0 NA TER SY C CO ROUN PTIO MPLE WI FF P RE 1 CF TRO D AL INAL STEM RING SIDE OSITION THEIR NORMAL UNENERGIZED POSITION R22 CM2A2 INDICATES A WIRE BETWEEN 2 AND COND MOTOR 2 TERMINAL A2 L CIRCUIT CIRCUITS Figure 5 3 Electrical Schematic Wiring Diagram Automatic O peration amp Rotron M otors D wg No 68R M 35 1038 1 Rev A Sheet 1 of 2 5 6 TERMINAL BLOCK PTB1 681 CISA 1 MANUAL RESET 30 87 CIRCUIT BREAKER 2
10. d GRD 10 GRD TCS gt R J X To STOP LIGHT 8 DS gt po lt gt lt T ET 15 Si ee 4 13 OPEN P DROP 2543 CLOSE P DROP 300410 AN PRE 2589 85 86 za GRD OR286 4 7 3 4 GRD EFR24 4 GRD FR86 5 9 e 7 3 4 CLOSE P RISE 400410 OPEN P DROP 325415 GRD HS lt o CLOSE P DROP 50 51 5 OPEN P RISE 6142 UPS3 lt gt lt lt 2 1 55 CLOSE P DROP 54 5 1 5 y nom Pre Use OPEN P RISE 6622 SRD lt e T gt z ol UPSI GRD KUTO OPEN P RISE 360410 CLOSE P DROP 28515 3 TEMPERATURE 5 SELECTOR Sere DER CFS cs GRD CFR14 H 3 4 17 TEMPERATURE o E SENSOR AUTO oR2 DE 30 30 1 2 lt lt y GRD og 55065 2897 gt a Sms E COOL O LOW g EO EE eet TCS HEATO 6 8 A 1 x GRD CFR24 OAUTO HEAT 19 1 1 t OREHEAT ur GRD EFR1 4 COOL po M lt gt Oto co gt 6 a O VEN SES 85 86 LOW AMBIANT ELECTRONIC 1 SWITCH THERMOSTAT RD A C CONTROL OPEN 64545 a SWITCH CLOSE 55 5 CACMS O Figure 5 4 Electrical Schematic Wiring Diagram Non Relay Board 22 Pin Connector Dwg No 68RM 35 1114 Rev C Sheet 2 of 2 5 9 NOTES 1 UNIT SHOW 2 RELAY CO 3 ADDRESS 5 CIRCUIT B 4 WIRE
11. 15 6 C If ambient tempera ture is lower than 60 F 15 6 C ice may form before moisture removal is complete H eat lamps or alternate sourcesof heat may be used to raise system temperature if necessary a Before refrigerant removal and evacuation leak test unit b Remove all remaining refrigerant charge in the system Connect evacuation manifold vacuum pump vacuum gauge reclaimer and hoses as shown in Figure 4 4 All hand valves on manifold should be closed The compressor service valves should be midseated if used The reclaimer valve should be closed d Start vacuum pump Slowly open manifold valveto the pump Open valve to the vacuum gauge E vacuate unit until vacuum gauge indicates 1500 microns 29 86 inches 75 8 cm H gvacuum Close gauge valve vacuum pump valve and stop vacuum pump e Opentherefrigerant cylinder vapor valve to break the vacuum Raise the pressure approximately 2 psig This will absorb any remaining moisture in the system for the second evacuation Close the cylinder valve f Repeat steps 4 and 5 g Evacuate again as described in step 3 to 300 500 microns H g vacuum 4 4 h Charge the system to specifications through the refrigerant recovery machine using manufactures charg ing procedure or as outlined in the following section 4 8 Charging the Refrigeration System
12. Owes CIRCUIT BREAKER 015 GRD CB2 40A 1 1 2 m GRD TI MANUAL RESET CIRCUIT BREAKER GRD PTB2 CB3 408 dee RED BLACK TI MANUAL RESET CIRCUIT BREAKER GRD PTB2 CBS 60 1 o RED BLACK TI MANUAL RESET CIRCUIT BREAKER SEE NOTE 3 GRD 2 4 604 1 02 GRD PTB2 COPTIONAL 10 MANUAL RESET CIRCUIT BREAKER OFF ENGINE COOLAN SWITCH OPT xry Fv pes LPS OPEN P RISE 425410 OPEN P DROP 643 CLOSE P DROP 300210 CLOSE P RISE 2525 O NO CONNECTION 50 5 1 5 UPS2 CLOSE P RISE 400 10 OPEN P DROP 325 15 v 62 lt CLOSE P DROP 52 5 1 5 OPEN PRISE 66 2 015 gt o o 2 2 Su n n6 2656 z mamo gt Z Re Na DI ME MN 2 AG GRD o CONNECTION 17 07 LOW AMBIANT SWITCH OPEN P RISE 360110 CLOSE P DROP 285415 OPEN 04515 FREEZE O CLOSE 65535 ELECTRONIC THERMOSTAT CTH Energized Circuit D2 ET De energized Circuit GRD Figure 2 6 Automatic High Speed Cool
13. COPTIONAL AQ v GRD MANUAL RESET CIRCUIT BREAKER ENGINE COOLANT SWITCH OFF J9 30 87 30 87 FR 30 87A 30 87A ACSR2 018 14 Sal 30 019 J e 0 STOP LIGHT CLOSE P DROP 50 5 1 5 OPEN P RISE 6142 uc HPS OPEN P RISE 425310 CLOSE P DROP 300410 LPS OPEN P DROP 613 CLOSE P RISE 2545 O NO CONNECTION Cos 014 E CLOSE P RISE 400110 PEN P DROP 32541 m OPEN 325 15 CLOSE P DROP 52 5 1 5 OPEN P RISE 66 2 62 015 gt o o 2 2 Su n 2 28 2 mamo gt Na DI ME MN 2 O L3 03 2 Het 7 07 FREEZE ELECTRONIC THERMOSTAT CTH L2 02 GRD 010 A6 BPR 86 85 v GRO GRN S8N___ CONNECTION WH BL 2 ORG GRN ONO CONNECTION m WH BL cM ORG e OPEN P RISE 360110 CLOSE P DROP 285 15 68 SC CFS LATH J9 o gt G 67 86 85 LOW AMBIANT Zb SWITCH OPEN 94515 013 CLOSE 65535 2 8
14. CB1 15 PIBI x BPR rBg due TI_MANUAL RESET 30 87 1 CIRCUIT BREAKER ESR 01 L e EFR2 HIGH c 8 TI MANUAL RESET 1 2 H 1 CIRCUIT BREAKER GRD ran AI 2 CB3 40 Hs 1112 A2 M D 6 3 TI MANUAL RESET 1 2 X ELE CIRCUIT BREAKER g CBS 60A ESR 1 CFRI CHIGH A O A2 52 TI_MANUAL RESET 1 2 CIRCUIT BREAKER 2 9411 RD PTE HIGH 1 Gegen cs GRD PTB2 O ko 52 TI MANUAL RESET 1 2 2 SZ CIRCUIT BREAKER 2 6382 1 quU cre SEE NOTE 3 HIGH MAIN POWER di 2 TERMINAL 24V DC 3 1 roi TI MANUAL RESET 30 87 CIRCUIT BREAKER OPTIONAL GRD REC11 ENGINE COOLANT E E zc SWITCH S 1 GRD are 4 SR 14 mE ECS e 1 GRD B TC ACSR GRD TC10 GRD lt TC9 gt 10 STOP LIGHT 3 CIR D2 TB2 TB3 lt gt lt a gt 1 OPEN de 425410 LES W I ERBE OPEN P DROP 2543 CLOSE P DROP 300410 CRE P RISE 2533 o 56 GRD 08286 5 e D 3 4 1 GRD FR24 GER 86 GRD FR86 5 e 3 4 CLOSE P RISE 400510 y OPEN P DROP 32515 SIL lt 0 gt CLOSE P DROP 50 5 1 5 63 CB BA DFS OPEN P RISE 6142 24 volts 5 e pen re lt oO TBS ESS CLOSE P DROP 54 5 1 5 y Tue o Wise OPEN P RISE 6642 GRD lt gt 4 du
15. RED BLACK 2 TI_MANUAL RESET Kee CIRCUIT BREAKER GRD PTB2 CBS 60 1 RED BLACK CMI TI_MANUAL RESET Kaz CIRCUIT BREAKER SEEN TES GRD PTB2 CB4 60 CA 1 RED wp BLACK MANUAL RESET CIRCUIT BREAKER COPTIONAL GRD PTB 10 1 MAIN POWER MANUAL RESET TERMINAL 24V DC CIRCUIT BREAKER NGINE COOLANT i ka VOLTS SWITCH o FROM BUS 5 KEES L_ 5 KE HEATO ACHS B4 019 lt lt 0 lt 0 gt HES 155 OPEN P RISE 30010 CLOSE P DROP 200 10 CODEN CHE 835 WH BL RG GRN MARLIN ORG EM2 C7 gt W STOP LIGHT RETURN AIR SENSOR 5 FREEZE SENSOR 1 Pe FREEZE SENSOR 2 5 K11 KI K K K K3 K UNLOADO Low OT L6 DE M 5 TO DEFROST SWITCH OPTIONAL NO CONNECTION REHEAT D4 LATH COPTIONAL OPEN 04535 CLOSE 55 5 Figure 5 1 Electrical Schematic Wiring Diagram 4 M ode
16. close manifold valve Midseat the suction service valve Remove the LPS jumper wire 5 Start unit and check compressor oil level 6 Backseat valve to remove hose from suction service valve and replace service valve caps Suction Gauge Service Manifold Valve Oil Container Compressor Figure 4 12 Compressor Oil Charge Connections 4 12 4 18 4 Adding Oil to Service Replacement C ompressor CAUTION The appropriate compressor oil must be used according to the refrigerant used in the system Refer to section 1 2 b Service replacement compressors may or may not be shipped with oil If compressor is without oil Add oil paragraph 1 2 b through the suction service valve flange cavity or by removing the oil fill plug ins 1 2 3 UNI 4 1 High Pressure 5 Bottom Plate Switch Connection 6 Oil Drain Plug 2 Low Pressure 7 Oil Sight Glass Switch Connection 8 Oil Pump 3 Suction Service 9 Unloader Solenoid Valve 10 Discharge Service 4 Oil Fill Plug Valve Figure 4 13 Compressor Model 056 a To Remove O il From the C ompressor 1 If the oil level recorded in step 4 18 2 is above 1 2 of the sight glass remove oil from the compressor If at full sight glass remove 2 3 4 pints of oil from the compressor to lower the level to 1 2 of the sight glass 2 Connect manifold gauges to the compressor 3 Close suction service valve frontseat and pump u
17. evaporator coil or suction line pump the system refriger ant into condenser coil and receiver tank as follows a Attach the gauge manifold as outlined in section 4 3 b Disconnect low pressure switch quick connect Install a jumper wire across switch connection to prevent the switch from disengaging the clutch Start the unit in by placing the driver s switch in the cool position The thermostat should be set below ambient temperature to ensure A C operation d Run unit for 5 10 minutes to allow system to stabilize e Frontseat close the liquid line valve at the inlet of the filter drier f Observe the suction gauge The pressure will drop off noticeably Stop the unit when a O to 10 in vacuum is reached g Stop the unit Observe the suction gauge If the reading increases restart the unit until the specified vacuum is achieved h Repeat the above step until the specified vacuum is maintained after stopping i Before opening the system a slight positive pres sure 1 2 psig is necessary to prevent air from being drawn into the system 45 REMOVING REFRIGERANT CHARGE A refrigerant recovery system is the recommended method for removingrefrigerant charge For the recovery system procedure refer to instructions provided by the manufacture A refrigerant recovery system should always be used whenever removing contaminated refrigerant from the system If a recovery system is not availab
18. evaporator fan motors to change from high to low speed operation See figure 2 8 When the vehicle interior temperature rises to 7 F above the thermostat setpoint the HIGH LOW switch switches from LOW to HIGH position this causes the evaporator fan motors to change from low to high speed operation RISING TEMPERATURE HIGH SPEED VENT 7 F ABOVE 5 F ABOVE SETPOINT SETPOINT SETPOINT 3 F BELOW SETPOINT 5 F BELOW ETPOINT HIGH SPEED VENT FALLING TEMPERATURE Figure 2 4 Temperature Controller Sequence During Vent M ode 2 3 5 Heat M ode See figure 2 5 To operate in the H eat mode place the A C control switch in the HEAT position In heat the reheat coolant valve RCV opensand closes on thermostat command to control vehicle interior temperature During the Heat mode the HEAT COOL switch controls operation of the booster pump relay BPR which in turn controlsthe operation of the booster pump When the vehicle interior temperature falls to 2 F below the setpoint H EAT COOL switch switches from COOL to HEAT position this energizes the BPR relay which energizes the booster pump allowing hot water to flow through reheat coils E vaporator fans are operating on low speed See figure 2 7 When the vehicle interior temperature falls to 5 F belowthe setpoint the H IG H LOW switch switchesfrom LOW to HIGH position this causes the evaporator fan motors to change from low to high speed op
19. s inherent inaccuracy A vacuum gauge is available from a refrigeration supplier 3 Evacuation Hoses 3 8 evacuation hoses the length to be determined by the application of the service set up 3 8 to 1 4 adapter connector are also needed to make compressor connections Evacuation hoses and adapters are available from your local refrig supplier Do not use standard refrigeration hosesto evacuate These standard hoses are designed for pressure not vacuum and may collapse duringevacuation 4 Recovery System A refrigerant recovery system is recommended for removing the refrigerant 5 Evacuation M anifold evacuation manifold is recommended for connecting the equipment needed for a proper evacuation The evacuation manifold can be made easily as shown in Figure 4 3 3 8 Flare Packless Fittings Valve 4 1 8 Fittings 1 8 NPT Fitting 2 ch Stock ES 1 2 Flare 1 1 2 a Fitting in 1 4 Flare Fitting Packless Valve 1 2 Flare Fitting Figure 4 3 E vacuation M anifold b Evacuation Procedure To help speed up the evacuation process and to increase the evaporation of moisture keep the ambient temperature above 60
20. 05 06 5 08 m H 04 03 H 07 17 FREEZE ELECTRONIC L2 THERMOSTAT TH Ei GRD LATH 69 MH BL ORG SENO NO CONNECTION CM2 ERN ONO CONNECTION 68 MH BL cay ORG S DEEN P RISE 360 10 CLOSE P DROP 285 15 gt e LOW AMBIANT SWITCH OPEN 45 5 CLOSE 055 5 59192 CES Figure 5 3 Electrical Schematic Wiring Diagram Automatic Operation amp Rotron Motors D wg No 68R M 35 1038 1 Rev A Sheet 2 of 2 5 7 SYMBOL DESCRIPTION ACHM HOURMETER OPTIONAL ACMS A C MODE SWITCH ACS A C SWITCH COFF ON ACSR A C STOP RELAY TIME DELAYED BPR 005 PUMP RELAY CB1 15A CIRCUIT BREAKER WATER PUMP RELAY CB2 35A CIRCUIT BREAKER MOTOR 2 CB3 35A CIRCUIT BREAKER EVAP MOTOR 1 AND 2 4 70A CIRCUIT BREAKER COND MOTOR 1 CBS 70A CIRCUIT BREAKER COND MOTOR 2 CBE 10A CIRCUIT BREAKER CLUTCH CB7 CIRCUIT BREAKER WATER PUMP CONDENSER FAN RELAY 1 2 CONDENSER FAN RELAY 2 CF CONDENSER FAN SPEED SWITCH 360 PSI CL CLUTCH CM1 CONDENSER FAN MOTOR 1 CM2 CONDENSER FA OTOR 2 COL1 CONDENSER OVERLOAD 1 COL2 CONDENSER OVERLOAD 2 CR CLUTCH RELAY CSRI CONDENSER SPEED RELAY 1 CSR2 CONDENSER SPEED RELAY 2 DI DIODE 1 D
21. 130 54 1897 1397 1370 20 7 185 130 128 s 57 2136 1592 1473 22 s 199 140 137 140 2292 1611 1540 a 214 330 ss 1727 1693 3 229 18r 158 150 66 2629 1848 1813 5 z 245 172 159 155 68 2811 1976 1937 4 14 SECTION 5 ELECTRICAL SCHEMATIC WIRING DIAGRAM 5 1 INTRODUCTION This section contains Electrical Schematic Wiring Diagrams covering the M odels listed in Table 1 1 5 1 NOTES 2 3 UNIT SHOWN IS IN T RELAY CONTACTS SHO ADDRESS SYSTEM EXA COND FAN RELAY 2 WIRE IDENTIFICATIO COLORS WHITE D GREEN G YELLOW 0 LEGEND SYMBOL DESCRIPTION 22 PIN CONNECTOR ACHM A C HOURMETER OPTIONAL ACMS A C MODE SWITCH ACR A C RELAY ACSRI A C STOP RELAY 1 ACSR2 A C STOP RELAY 2 BPM BOOST PUMP MOTOR BPR BOOST PUMP RELAY CBI 1 CIRCUIT BREAKER WATER PUMP RELAY CB2 40A CIRCUIT BREAKER CEVAP MOTOR 2 CB3 40A CIRCUIT BREAKER EVAP MOTOR 1 AND 2 CB4 60A CIRCUIT BREAKER COND MOTOR 1 CB5 60A CIRCUIT BREAKER COND MOTOR 2 CB6 10 CIRCUIT BREAKER CLUTCH CFS CONDENSER FAN SPEED SWITCH 360 PSI CL CLUTCH CM1 CONDENSER FAN MOTOR 1 2 CONDENSER FAN MOTOR 2 CR CLUTCH RELAY D1 D27 DIODE 1 DIODE 27 DFS DEFROST SWITCH OPTIONAL ECS ENGINE COOLANT SWITCH OPTIONAL EMI EVAPORATOR FAN MOTOR 1 EM2 EVAPORATOR FAN MOTOR 2 FR FAULT RELAY HPS HI
22. 2 6 POWER TERMINAL BLOCK TO DEFROST lt PTBI CBI 15 E 15 m Big TI MANUAL RESET CIRCUIT BREAKER Ta RCV CB2 40A il EK 5 2 RED BLACK GRD a TI MANUAL RESET CIRCUIT BREAKER GRD 2 40A E Ri ACK TI MANUAL RESET CIRCUIT BREAKER GRD PTB2 CBS 604 12512 RED 1 BLACK TI MANUAL RESET CIRCUIT BREAKER SEE NOTE 3 CBA 604 gt 152 RED ce TI MANUAL RESET CIRCUIT BREAKER v GRD PTB2 v GRD PTB2 OPTIONAL A2 MAIN POWER T ET CR FR ACSR1 TERMINAL 24V DC J9 ET TI MANUAL RESET Genk 87 soa 87 30 ta CIRCUIT BREAKER OFF ENGINE COOLANT SWITCH COPT FR gt ACS 30 018 B4 ACSR2 020 Lo 14 AC STOP LIGHT 87 30 019 2 K Te gt gt D 1 86 85 1 E 425110 oro gt OPEN P DROP 643 CLO P DROP 300410 SE P DROP 3 CLOSE P RISE 2525 014 SEN O NO CONNECTION 5 setz ORS due 5 CLOSE P DROP 50 551 5 OPEN P RISE 61 2 F1 CLOSE P RISE 400410 ER gt OPEN P DROP 1 UPS2 DROP 325415 DE 52 4 CLOSE P DROP 52 5 1 5 OPEN P RISE 66 2 DIS UPS3 m GR 15 5 P ono gt UPS1 a 4 023 4 Halts 1919 1
23. 40 1 2 TO DEFROST lt A lt 016 gt Auro GRD ener RD TI MANUAL RESET CIRCUIT BREAKER 40 1 RED_ y BLACK A GRD PTB2 TI MANUAL RESET CIRCUIT BREAKER CBS 15552 BLACK wi RED 1 BLACK GRD PTB2 MANUAL RESET CIRCUIT BREAKER SEE NOTE 3 CB4C60A gt 5 GRD PTB2 MAIN POWER TERMINAL 24V DC TI MANUAL RESET CIRCUIT BREAKER CBE 1 1 OA MANUAL CIRCUIT BI OFF ENGINE s e RESET 30 IREAKER 24 VOLTS Lees SHITCH OPD o FROM PERSIA DS zs 84 R lt uo BLACK ACSRI 20 COPTIONAL GRD PTB2 lt lt HPS gt gt OPEN P RISE 425410 CLOSE P DROP 300410 eoo LPS OPEN P DROP 6 3 CLOSE PRISE 2545 SENO CONNECTION CLOSE P DROP 50 5 1 5 OPEN P RISE 6142 WH BL fon ORG GRN WH BI ORG F2 Le UPS2 63 lt I E UPS3 M0 o UPS 2 88 B Su 26 n6 243838 28535859 SE S Ba SSASAS mE 525535565
24. CSR 1 Refer to paragraph 1 2 for switch settings this will cause the condenser fan motors CM 1 and CM 2 to run at high speed On units with Rotron motors evaporator fan motor speed control is accomplished internally Booster Pump Relay BPR The booster pump relay BPR is plugged into the relay board on the electrical control panel located in the rear compartment of the unit See figure 1 3 Thisrelayis energized duringthe reheat and heating modes W hen the booster pump relay BPR is energized a set of internal contacts will close to activate the booster pump motor 1 6 COOLANT VALVE reheat coolant valve RCV is located in the evaporator section of the unit at the rear of the bus See figure 1 1 The valve is an electrically operated solenoid valve controlled by thermostat command The RCV controls the coolant flow to the heater coil during heating The valve is normally closed and opens when the coil is energized and closes when the coil is de energized When the thermostat calls for heating the RCV coilis energized the plunger islifted and the pilot port isopened to relievethe pressure on top of the diaphragm Seefigure 1 5 Now the valve inlet pressure will act on the bottom portion of the diaphragm lifting the diaphragm to open the main port O ncethe port isopen the diaphragm isheld off the seat by the pressure difference across the port When the coil isde energized the plunger drops due
25. Cool R 134a 68RM35 704 Heat Only N A Revised 10 9 96 ROADSIDE LG CURBSIDE RS CS 27 9 L 10 11 28 12 13 14 26 N r N ul N A 21 Condenser Fan Motor CM1 Filter Drier Outlet Valve Filter Drier Low Ambient Thermostat LATH Filter Drier Inlet Valve Condenser Fan Motor CM2 Condenser Coil Pressure Unloader Switch UPS3 Discharge Line Check Valve Condenser Fan Speed Switch CFS 11 Receiver Sight Glass Upper 12 Receiver Sight Glass Lower 13 Receiver 14 Evaporator Fan Blower 15 Discharge Line Connection 20 19 18 17 16 15 Suction Line Connection Unloader Pressure Switch UPS1 Unloader Pressure Switch UPS2 Evaporator Fan Blower Motor EF M2 Moisture Indicator Reheat Coolant Valve RCV Evaporator Fan Blower Motor EFM1 Access Panel Inlet Hot Water Connection Outlet Hot Water Connection Evaporator Fan Blower Electrical Interface Discharge Line Shut Off Valve Figure 1 1 Unit Assembly Back View CURBSIDE CS ROADSIDE RS
26. Operation Cool Clutch Cycling Mode 2 3 4 Nent Mode curs Rb x RR RARE 235 Heat M ode isse mean 3 TROUBLESHOOTING Sch U nnIEWIIBNOECOOl ere ere pm REOR EPIRI MEE pis 32 UnitRunsButHasInsufficient Cooling 3 3 Abnormal Pressure zs xsv hk pe ph rr E UP E RR E 34 Abnormal Noise and Vibrations 341 Abnormal NOISe ec ee Rex EIER Rd Rex ode Re Ex Reese mods 3 4 2 Abnormal Vibration 35 Temperature Controller M 36 Evaporator Air Flow or Restricted Air Flow 37 Expansion Valve Malfunction 2 22222 38 Noor Insufficient Heating 4 SERVICE sise eme monte retenue nent 41 Maintenance Schedule 42 Suction and Discharge Service Valves 43 Manifold GaugeSet ia 44 SysemPumpDown ccc cee cee eee eee isk tent nets 45 Removingthe Refrigerant Charge 46 Refrigerant Leak 47 Evacuation and Dehydration
27. Selector Switch amp Rotron Motors D wg No 68R M 35 1038 4 Rev D Sheet 2 of 2 5 3 LEGEND SYMBOL DESCRIPTION ACHM HOURMETER OPTIONAL ACMS A C MODE SWITCH ACS A C SWITCH OFF OND ACSRI A C STOP RELAY 1 ACSR2 A C STOP RELAY 2 AHR AUTOMATIC HEAT RELAY BPR BOOST PUMP RELAY CBI 1 CIRCUIT BREAKER WATER PUMP RELAY CB2 35A CIRCUIT BREAKER EVAP MOTOR 2 CB3 35A CIRCUIT BREAKER EVAP MOTOR 1 AND 2 CB4 70A CIRCUIT BREAKER COND MOTOR 1 CBS 70A CIRCUIT BREAKER COND MOTOR 2 CB6 10A CIRCUIT BREAKER CLUTCH CFRI CONDENSER FAN RELAY 1 CFR2 CONDENSER FAN RELAY 2 CF CONDENSER FAN SPEED SWITCH 360 PSI CL CLUTCH CMI CONDENSER FAN MOTOR 1 2 CONDENSER FAN MOTOR 2 COLI CONDENSER OVERLOAD 1 COL2 CONDENSER OVERLOAD 2 CR CLUTCH RELAY CSR1 CONDENSER SPEED RELAY 1 01 027 DIODE 1 DIODE 27 DF DEFROST SWITCH OPTIONAL ECS ENGINE COOLANT SWITCH OPTIONAL EVAPORATOR MOTOR 1 EM2 EVAPORATOR FAN MOTOR 2 EFRI EVAPORATOR FAN RELAY 1 EFR2 EVAPORATOR FAN RELAY 2 EOL1 EVAPORATOR OVERLOAD 1 EOL2 EVAPORATOR OVERLOAD 2 ESR EVAPORATOR SPEED RELAY ESS EVAPORATOR SPEED SWITCH FHV FLOW HEAT VALVE FR FAULT RELAY HPS HIGH PRESSURE SWITCH 425 PSI ILR INTERLOCK RELAY LATH LOW AMBIENT THERMOSTAT OPTIONAL PS LOW PRESSURE SWITCH LSR LOW SPEED RELAY ORI EVAPORATOR OVERLOAD RELAY 1 OR2 EVAPORATOR OVERLOAD RELAY 2 PTB POWER TERMINAL BLOCK RCV REHEAT COOLANT
28. The H IGH L O W switch will remain in the LOW position keeping the evaporator fans operating on low speed in the vent mode When the vehicle s interior temperature falls to 2 F below the thermostat setpoint the H EAT COOL switch switches to the HEAT position to energize the booster pump relay BPR water pump relay WPR and the reheat coolant valve RCV this starts the flow of hot water through the reheat coil The HIGH LOW switch will remain in the LOW position keeping the evaporator fan motors operating on low speed The unit is now operating in the low speed heat mode When the vehicle s interior temperature falls to 5 F below the thermostat setpoint the H EAT COOL switch remains in the HEAT position But the HIGH LOW switch switchesfrom LOW to HIGH position this causes the evaporator fan motors to change from low to high speed operation 2 3 2 Air Conditioning O peration Reheat M ode See figure 2 2 To operate in the Reheat mode placethe A C control switch in the R EH EAT position In the R eheat mode the reheat coolant valve opens and closes on thermostat demand to control vehicle interior temperature whilethe air conditioning mode continues to operate During the Reheat mode the HEAT COOL switch controls the operation of the reheat control valve RCV and the booster pump The HIGH LOW switch controls the evaporator fan speed low or high While the air conditioning unit is operating in the Reheat mode the clutch
29. When in the AUTO position evaporator fan speed is controlled by the temperature controller switch 1 7 c Thermal Switches Engine Coolant Switch ECS O ptional Supplied by OE M The engine coolant switch ECS is located on the engine block of the vehicle and senses the engine coolant temperature The ECS is a normally open switch which closes on a temperature rise to complete a path to energize the control circuits If this switch is used and the water temperature is below the switch setpoint then the system will not operate Condenser Motor Overload COL1 and COL2 Not Installed on Units with Rotron Motore E ach condenser fan motorisequipped with an internal thermal protector switch If excessively high motor temperature exists the COL switch will open to de energize the corresponding condenser fan relay CFR 1 CFR 2 this will stop the corresponding condenser fan motor Evaporator Motor Overload EOL1 and EOL2 Not Installed on Units with Rotron M otors Each evaporator fan motor is equipped with an internal thermal protector switch embedded in the motor windings If excessively high motor temperature exists the EOL switch will open to de energize the corresponding evaporator fan relay EFR 10r EFR2 this will stop the corresponding evaporator fan motor Rotron brushless motors are protected by manual circuit breakers in the system Low Ambient Thermostat L ATH Optional Supplied by OEM The
30. low ambient thermostat LATH monitors temperature outside the vehicle The switch opens at 45 5 F 73 2 8 and closes at 55 5 F 12 9 2 8 C When the outside temperature is below the open setting of the switch the switch opensto stop the compressor clutch and condenser fans The low ambient thermostat is mounted on the condenser coil d Pressure Switches 949 Condenser Fan Speed Switch CFS Not Installed on Units with Rotron M otors The condenser fan speed switch CFS senses refrigerant discharge line pressure to control condenser fan speed If the condenser coil discharge pressure rises to the CFS cutout setting the switch will open to de energize the condenser speed relay CR 51 this will cause the condenser fan motors CM 1 and CM 2 to run at high speed When the pressure dropsto the 5 cut in setting the switch will close energizing CSR 1to run the condenser fan motors at low speed Refer to paragraph 1 2 for switch settings On units with brushless Rotron motors the pressure switch operation isthe same except there is no speed relay 11 switchingisaccomplished internal to the motor through the condenser motor CM 1 and CM 2 circuitry Revised 10 9 96 Unloader Pressure Switches UPS1 UPS2 UPS3 The unloader pressure switches UPS1 UPS2 and U PS3 control unloader operation during A C mode of operation U nloader pressure switches U PS1 and U PS2 close pressure drop to energize unloade
31. should the system be pressurized above 100 psig when leak testing 2 Check for leaks The recommended procedure for finding leaks in a system is with a halide torch or electronic leak detector 3 Remove the refrigerant used to pressurize the system prior to leak repair using a recovery system 4 Repeat the entire procedure if necessary 5 Evacuate and dehydrate the system as outlined in section 4 7 6 Charge the unit as outlined in section 4 8 4 7 EVACUATION AND DEHYDRATION Proper evacuation and dehydration procedures are imperative when service repairs or component replace ment are performed on the system to ensure proper unit performance and long compressor life The results of improper evacuation are harsh condensible gases in the system result in high head pressure moisture may cause ice blockage at the expan sion valve moisture and refrigerant may react to form an acid This acid may cause copper plating of the bearing surfaces and eventual compressor failure a Equipment Needed 1 Vacuum Pump good vacuum pump 3to 5 cfm volume displacement at atmospheric pressure A pump of this capacity is available through the Carrier Service Parts CTD P N 07 00176 01 2 Thermistor Vacuum Gauge A thermistor vacu um gauge electronic vacuum gauge measures the low absolute pressures necessary to remove moisture from the system A compound gauge manifold gauge set is not recommended because of it
32. to the system High Pressure Gauge Low Pressure and Vacuum Gauge Hand Valve Hand Valve Opened A Closed Backseated Frontseated A Hose Connection to C Connection to or for Low Side of System Refrigerant Cylinder B Hose Connection to Oil Container High Side of System Figure 4 2 Gauge anifold Set a Installing the G auge M anifold Set To avoid the unsafe conditions near the running compressor the recommended gauge manifold set con nection isto the service ports located on the suction and discharge drop tubes These service port are located above the engine next to the fire wall in the engine compartment The drop tube connections are equipped with schrad er fitting which open when the connection is made 1 Frontseat the gauge manifold hand valves to close off the center port 2 Connectthe high side hose tightly to the discharge drop tube service port 3 Connect the low side hose loosely to the suction drop tube service port 4 Loosen gauge manifold charging center hose at dummy fitting 5 Open counterclockwise manifold discharge hand valve to purge discharge line through the center hose dummy fitting Tighten the center hose dummy fitting 4 2 6 Open counterclockwise manifold suction hand valve to purge suction hose Tighten the suction hose fitting at the suction quick connect schrader fitting 4 4 SYSTEM PUMPDOWN To service or replace the filter drier expansion valve
33. to the kick off spring and closes the pilot port The pressure above the diaphragm is no longer vented to the downstream side of the valve and the diaphragm drops closing the main port The valve s maximum operating pressure differential MOPD is 35 The MOPD is the maximum pressure differential against which the solenoid will open The valve hasa 10 gallon per minute minimum capacity with a 3 psig pressure differential across the valve SS 12 OUTLET PORT 1 Valve Body 7 Coil 2 Equalizer Port 8 Coil Housing 3 O Ring 9 Coil Retaining Screw 4 Closing Spring 10 Nameplate 5 Plunger 11 Diaphragm 6 Kick Off Spring 12 Pilot Port Figure 1 5 Reheat Coolant Valve 1 9 1 7 MOISTURE LIQUID INDICATOR The moisture liquid indicator is located on the liquid line between the filter drier and the receiver The element in the indicator is highly sensitive to moisture and will gradually change color in direct relation to an increase or decrease in the moisture content of the system The dry caution wet system operating conditions are then easily determined by matching the element color with the four colors displayed on the reference label Colors change as often as the system moisture content changes 1 8 HEATER COOLANT FLOW CYCLE Heatingis controlled by the thermostat which controls the operation of the reheat coolant valve R CV W hen the coolant valve solenoid is energized the valve will open to allow engi
34. 12 Suction Line Figure 1 7 Air Conditioning Refrigerant Cycle SECTION 2 OPERATION 2 1 STARTING AND STOPPING INSTRUCTIONS a Starting 1 Start the vehicle engine 2 Place the A C switch in the ON position 3 Place the A C control switch in the desired mode of operation position AUTO COOL VENT HEAT or REHEAT NOTE The engine coolant must be warm enough to close the engine coolant switch if installed for unit operation to start b Stopping 1 Place the A C switch to the OFF position NOTE Be sure air conditioning unit is turned off before stopping the vehicle engine 2 2 PRE TRIP INSPECTION After starting unit allow system to stabilize 10 to 15 minutes and proceed as follows 1 Listen for abnormal noises 2 Check compressor oil level 3 Check refrigerant level 4 Check moisture liquid indicator 2 3 UNIT OPERATION The desired modes of operation Auto Cool Vent Heat or Reheat are selected manually with the air conditioning switch located on the driver s switch panel When a mode of operation is selected the control thermostat senses the vehicle s interior temperature and automatically controlsthe system to maintain the desired temperature setpoint The unit control circuits and components operate on 24 volt power supplied by the bus battery or alternator 2 3 1 Air Conditioning O peration Auto M ode See figure 2 1 To operate in the Auto mode of operation Place the A C control s
35. 2 DIODE 2 DS DIODE 5 DFS DEFROST SWITCH COPTIONAL ECS ENGINE COOLANT SWITCH OPTIONAL EF MI EVAPORATOR FAN MOTOR 1 EFM2 EVAPORATOR FAN MOTOR 2 EFRI EVAPORATOR FAN RELAY 1 2 EVAPORATOR FAN RELAY 2 22 PIN CONNECTOR 1 EVAPORATOR OVERLOAD 1 WIRING SIDE EOL2 EVAPORATOR OVERLOAD 2 ESR EVAPORATOR SPEED RELAY ESS EVAPORATOR SPEED SWITCH FR FAULT RELAY 5 HIGH PRESSURE SWITCH 425 PSI LATH LOW AMBIENT THERMOSTAT OPTIONAL LPS LOW PRESSURE SWITCH ORI EVAPORATOR OVERLOAD RELAY 1 OR2 EVAPORATOR OVERLOAD RELAY 2 1 POWER TERMINAL BLOCK RCV REHEAT COOLANT VALVE RE RECTIFIE TC TERMINAL BLOCK C NOTES TD TERMINAL BLOCK 7D 1 UNIT SHOWN IS IN THE OFF POSITION TH ELECTRONIC THERMOSTAT 2 RELAY CONTACTS SHOWN ARE IN THEIR NORMAL UNENERGIZED POSITION UPSI UNLOADER PRESSURE SWITCH 1 QURCUIT BREAKER 6 TERMINAL 1 AND CLUTCH RELAY TERMINAL 30 UPS2 UNLOADER PRESSURE SWITCH 2 4 WIRE IDENTIFICATION SYSTEM UPS3 UNLOADER PRESSURE SWITCH 3 COLORS WHITE DC CONTROL CIRCUIT UNLOMDER VALVE e GREEN DE meurs UV2 UNLOADER VALVE 2 5 THIS SCHEMATIC APPLY S TO RM35 UNITS WITH SERIAL NUMBERS WPR WATER PUMP RELAY BEFORE 12 000026 dk Indicates Load NDICATES WIRE GROUND Motor amp Coils INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING 0 0 Temperature Switch Opens NDICATES A CONNECTION LUG SCREW ETC on Rise in Temperature xe NDICATES A CONNECTOR Pressure Switch Opens O4 Ho ND
36. 7 4 36 4 56 4 76 5 17 5 61 6 07 6 31 7 07 7 6 8 16 8 74 9 36 10 0 10 67 11 37 12 09 12 86 13 64 14 47 15 33 16 22 17 15 18 11 19 10 20 12 21 17 22 31 23 53 24 78 26 06 27 34 28 65 29 96 Table 4 3 R 134a Temperature Pressure Chart BOLD Inches Mercury Vacuum cm Hg Vac 9 1 84 1 95 1 92 6 2 08 2 0 2 3 2 33 2 29 35 1 2 47 2 42 0 1 2 82 2 76 64 1 1 42 are dek us 35 BER 3708 0 49 30 2 desi E 22121 8 89 0 12 38 3 332 7 533 7007 240 A 251 003 220 008 3 60 80 1 EE 2229 20201 RENE TELA 1 NI WH 85 E 100 5 0 500 5 53 6 10 711 0 78 7 86 7 953 6 70 104 3 114 0 0 EC Bar 240 049 35 31 033 3 21 023 20224 007 EH 14326 003 21520 0000 008 020 0 26 032 ARI 39 039 E 53 E ES EJ EE JEA ET 4 45 51 37 7 46 24 27 BENT 29 x 7 33 95 35 8 01 38 12 10 8 120 132 IKE ES 873 931 osa oss mo 43 1464 102 1009 2 093 osr 15 46 1584 114 1092 Lu 10 345 102 100 120 a9 1712 12 04 1185 16 9 158 331 109 125 52 1946 1298 1223 131 329 138
37. Clutch Relay CR The clutch relay CR is plugged into the relay board on the electrical control panel located in the rear compartment of the unit See figure 1 3 When the CR relay is energized a set of internal contacts will close to activate the compressor clutch CL to start therefrigerant E vaporator Fan Relays EFR1 and EFR2 Not Installed on Units with Rotron M otors Evaporator fan relays EFR 1 EFR 2 are installed on the electrical control panel located in the rear compartment of the unit See figure 1 3 When the air conditioning switch ACS is placed in either the ON position EFR1 and EFR2 relays are energized When energized a set of internal EFR 1 and EFR2 contacts are closed to start the evaporator fan motors Rotron motors require no external relays 1 8 E vaporator Overload Relays and OR2 Not Installed on Units with Rotron M otors Evaporator overload relays OR1 and OR2 are plugged into the relay board on the electrical control panel located in the rear compartment of the unit See figure 1 3 These relays are energized at the same moment the evaporator fan relaysare The OR 1and OR 2relays when energized will close a set of internal contacts to energize the evaporator speed relay ESR Evaporator Speed Relay ESR Not Installed on Units with Rotron M otors The evaporator speed relay ESR isinstalled on the electrical control panel located in the rear compartment of
38. Dehydrate and evacuate compressor to 500 microns 29 90 Hg vacuum 75 9 cm Hg vacuum Turn off valves on both linesto pump 5 Fully backseat open both suction and discharge service valves 6 Remove vacuum pump lines and install manifold gauges 7 Start unit and check for noncondensibles 8 Check refrigerant level and add if necessary 9 Check compressor oil level refer to section 4 18 2 Add oil if necessary 10 Check compressor unloader operation 11 Check refrigerant cycles 4 18 2 Checking the Compressor Oil L evel a Operatetheunitin high idle cooling for at least 20 minutes b Check the oil sight glass on the compressor to ensure that no foaming of the oil is present after 20 minutes of operation If the oil is foaming excessively after 20 minutes of operation check the refrigerant system for flood back of liquid refrigerant Correct this situation before adding oil Check the level of the oil in the sight glass with the compressor operating The correct level should be between 1 4 and 1 2 of the sight glass If the level is above 1 2 oil must be removed from the compressor If the level is below 1 8 add oil to the compressor as outlined in the following section 4 18 3 Adding Oil to the Installed Compressor CAUTION The appropriate compressor oil must be used according to the refrigerant used in the system Refer to section 1 2 b Two methods for adding oil are the oil pump method and clos
39. Disconnect the wire connections to the unloader 6 Attach sling or other device to compressor to remove The compressor weighs approximately 146 105 7 Remove the clutch from the compressor NOTE If the compressor isto be returned to the factory drain oil from defective compressor before shipping b Installing NOTE It is important to check the compressor oil level of the new compressor and fill if necessary 1 Theoriginal unloader valve must be transferred to the replacement compressor The plug arrangement removed from the replacement is installed in the original compressor asa seal f piston isstuck it may be extracted by threading a socket head cap screw into top of piston A small Teflon seat ring at bottom of piston must be removed NOTE The service replacement compressor is sold without shutoff valves but with valve pads These should be placed on the old compressor before shipping Check oil level in service replacement compressor If none add the applicable amount outlined in section 1 2 b 2 Remove the high pressure switch and install on new compressor after checking switch setting refer to section 4 11 3 Install compressor in unit by reversing step 4 18 a It is recommended using new locknuts when replacing compressor Install new gaskets on service valves and tighten bolts uniformly 4 Attach two lines with hand valves near vacuum pump to the suction and discharge service valves 4 11
40. EFR2 HIGH 8 4 TI MANUAL RESET 1 2 tK 8 1 CIRCUIT BREAKER GRD CTC9 3 40 zeg 5 O O 552 A2 M x 3 e TI MANUAL RESET 1 2 GRO PT CIRCUIT BREAKER 7 CBS 60 ESR 1 CHIGH 1 2 15 2 52 7 TI MANUAL RESET y 112 om N SX CIRCUIT BREAKER 2 OR oi pen HIGH ES 2 GRD PTB2 ko 52 TI MANUAL RESET 1 75 cm N S il CIRCUIT BREAKER 5 CSR tico SEE NOTE 3 MAIN POWER x rao TERMINAL 24V DC a DA ber TI MANUAL RESET 30 67 CIRCUIT BREAKER OPTIONAL GRD REC11 ENGINE COOLANT E ta SWITCH COPT e 1 GRD Bis s c 4 ECS 1 GRD TB B TC ACSR GRD TC10 GRD lt TC9 2 d 2 STOP LIGHT 6 9 bo TB2 TB3 lt gt lt ST gt 1 OPEN HE 425410 ps uos OPEN P DROP 25 3 CLOSE P DROP 300410 P RISE 253 om 85 85 tai GRD 08286 D 3 4 1 GRD FR24 GER 85 Sa GRD FREG 5 5 d 3 4 CLOSE P RISE 400510 y OPEN P DROP 325415 SOCIO 4 lt 0 gt CLOSE P DROP 50 5 1 5 63 CB BA DFS OPEN P RISE 6122 24 volts 85 Sg reo lt gt TBS ESS CLOSE P DROP 54 5 1 5 y prse OPEN P RISE 6642 SRO L 10 lt gt H UPS1 GRD 4 0 OPEN P RISE 360 10 CLOSE P DROP 285415 A TEM
41. EVAPORATOR FAN MOTOR 1 EM2 EVAPORATOR FAN MOTOR 2 FR FAULT RELAY HPS HIGH PRESSURE SWITCH LATH LOW AMBIENT THERMOSTAT OPTIONAL Se CRINE LPS LOW PRESSURE SWITCH PTB POWER TERMINAL BLOCK RCV REHEAT COOLANT VALVE TH ELECTRONIC THERMOSTAT UPSI UNLOADER PRESSURE SWITCH 1 UPS2 UNLOADER PRESSURE SWITCH 2 UPS3 UNLOADER PRESSURE SWITCH 3 SE UVI UNLOADER VALVE 1 UV2 UNLOADER VALVE 2 INDICATES RELAY BOARD CONNECTION WPR WATER PUMP REL INDICATES WIRE GROUND INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING INDICATES A CONNECTION LUG SCREW ETC lt lt INDICATES CONNECTOR Fo INDICATES A NORMALLY OPEN CONTACT Oo INDICATES A NORMALLY CLOSED CONTACT c INDICATES BUS INTERFACE CONNECTOR PIN LOCATION NOTES INDICATES RELAY BOARD TRACE 1 UNIT SHOWN IS IN THE OFF POSITION OR IN OPERATING MODE SHOWN 2 RELAY CONTACTS ARE IN THE APPLICABLE POSITION FOR THE OPERATING MODE SHOWN 3 ADDRESS SYSTEM EXAMPLE CFR22 CM2A2 INDICATES A WIRE BETWEEN COND FAN RELAY 2 TERMINAL 2 AND COND MOTOR 2 TERMINAL A2 4 WIRE IDENTIFICATION SYSTEM COLORS WHITE DC CONTROL CIRCUIT GREEN GROUND YELLOW OPTIONAL CIRCUITS 2 5 POWER TERMINAL BLOCK PTBI MAIN POWER TERMINAL 24V DC ks eue ec CLOSE P DROP TI MANUAL RESET CIRCUIT BREAKER OPEN P RISE 6142 TO DEFROST Dj 1 15 BPR E ibs TI MANUAL RESET 30 Lo
42. Energized Circuit PTB2 PTB2 PTB2 PTB2 De energized Circuit Figure 2 8 Automatic Low Speed Vent INDICATION TROUBLE 3 1 UNIT WILL NOT COOL Compressor will not run Electrical malfunction SECTION 3 TROUBLESHOOTING POSSIBLE CAUSES V Belt loose or defective Compressor malfunction Clutch malfunction Safety device open switch defective Low Ambient Thermostat open Circuit breaker CB6 open Temperature Controller malfunction Engine Coolant Switch ECS Open If installed 3 2 UNIT RUNS BUT HAS INSUFFICIENT COOLING Compressor Refrigeration system 3 3 ABNORMAL PRESSURE High discharge pressure Low discharge pressure High suction pressure Low suction pressure Low evaporator air flow Suction and discharge pressures tend to equalize when unit is operating Compressor valves defective V belt loose Abnormal pressures No or restricted evaporator air flow Expansion valve malfunction Restricted refrigerant flow Low refrigerant charge Service valves partially closed Safety device open Refrigerant overcharge Noncondensibles in system Condenser fan motor rotation incorrect Condenser coil dirty Compressor valves s worn or broken Low refrigerant charge Compressor valves worn or broken Suction service valve partially closed Filter drier inlet or outlet valves partially closed Filter drier partially plugged Low refrigerant charge Expansion valve malfunction Restri
43. GH PRESSURE SWITCH HR HEAT RELAY HR2 HEAT RELAY 2 LATH LOW AMBIENT THERMOSTAT OPTIONAL LPS LOW PRESSURE SWITCH PTB POWER TERMINAL BLOCK RCV REHEAT COOLANT VALVE TH ELECTRONIC THERMOSTAT UPSI UNLOADER PRESSURE SWITCH 1 UPS2 UNLOADER PRESSURE SWITCH 2 UPS3 UNLOADER PRESSURE SWITCH 3 UVI UNLOADER VALVE 1 Uv2 UNLOADER VALVE 2 02 NDICATES PLUG LOCATION ON RELAY BOARD NDICATES A WIRE GROUND GRD INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING O NDICATES A CONNECTION LUG SCREW ETC Ke NDICATES A CONNECTOR FO NDICATES A NORMALLY OPEN CONTACT OO NDICATES A NORMALLY CLOSED CONTACT KLE NDICATES BUS INTERFACE CONNECTOR PIN LOCATION NDICATES RELAY BOARD TRACE HE OFF POSITION WN ARE IN THEIR NORMAL UNENERGIZED POSITION MPLE CFR22 CM2A2 INDICATES A WIRE BETWEEN TERMINAL 2 AND COND MOTOR 2 TERMINAL A2 SYSTEM C CONTROL CIRCUIT ROUND PTIONAL CIRCUITS FOR REHEAT MODE OF OPERATION UNIT TO BE SET UP UNIT RUNS IN HIGH SPEE D ALL THE TIME EXCEPT IN HEAT MODE WIRING SIDE Figure 5 1 Electrical Schematic Wiring Diagram 4 M ode Selector Switch amp Rotron Motors Dwg No 68R M 35 1038 4 Rev D Sheet 1 of 2 5 2 POWER TERMINAL BLOCK 15A PTBI BPR 1 7 T MANUAL RESET 30 87 CIRCUIT BREAKER 016 Ei CB2 40 1 O 1 RED ew BLACK GRO 7 TI MANUAL RESET KL CIRCUIT BREAKER GRD PTB2 CB3 40 1
44. ICATES A NORMALLY OPEN CONTACT on Rise in Pressure NDICATES NORMALLY CLOSED CONTACT QO Pressure Switch Opens XLS NDICATES BUS INTERFACE CONNECTOR on Drop in Pressure PIN LOCATION Figure 5 4 Electrical Schematic Wiring Diagram Non Relay Board 22 Pin Connector Dwg No 68R M 35 1114 Rev C Sheet 1 of 2 5 8 POWER TERMINAL BLOCK Gas TO DEFROST BH 1 1 D 2 BPR O Qu lt TI MANUAL RESET 30 87 Ka CIRCUIT BREAKER der 4 nov Ys ESR DI 82990 2 HIGH GRD 6 9 OH AK 4 L TI MANUAL RESET 1 2 lt CIRCUIT BREAKER Ge AI 404 Hs S 1 2 eu A2 M x 3 r TI MANUAL RESET 1 2 RDA 5152 CIRCUIT BREAKER 7 CBS 604 ESR 2 CFRI men ATEN D o4 2 52 TI MANUAL RESET 1 2 897 CIRCUIT BREAKER 2 CRT GRO HIGH 1 CFR2 GRD PTB2 2 52 TI MANUAL RESET 1 2 8 CIRCUIT BREAKER 2 6582 er oo SEE NOTE 3 AU MAIN POWER 10 p T CR 2 TERMINAL 24V DC 533 doi To TI MANUAL RESET 30 87 7 a 1 CIRCUIT BREAKER OPTIONAL GRD RECI1 OFF ENGINE COOLANT 24 we SWITCH PD lt H 1 6 GRD o 0 FROM BUS ACS ECS 1 GRO T02 H A B
45. IDE COLORS W G Y 5 THIS SCHE AFTER 12 Figure 5 5 Electrical Schematic Wiring Diagram Non Relay Board Terminal Strip Connections SYMBOL ACHM ACMS ACS ACSR BPR CB1 CB2 CB3 CB4 CBS CB6 CB CFR1 CCC CS C H1HDPDVOSOCCITNMMMMMMMMMO 19 WATER PUMP 1 INDICATES A WIRE GROUND INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING INDICATES A CONNECTION LUG SCREW ETC lt lt INDICATES CONNECTOR INDICATES TERMINAL BLOCK INDICATES TERMINAL BLOCK B o4 Fo INDICATES A NORMALLY OPEN CONTACT INDICATES NORMALLY CLOSED CONTACT S IN THE OFF POSITION TACTS SHOWN ARE IN THEIR NORMAL UNENERGIZED POSITION YSTEM EXAMPLE CB61 CR30 INDICATES A WIRE BETWEEN REAKER 6 TERMINAL 1 AND CLUTCH RELAY TERMINAL 30 TIFICATION SYSTEM DC CONTROL CIRCUIT REEN GROUND ELLOW OPTIONAL CIRCUITS MATIC APPLY S TO RM35 UNITS WITH SERIAL NUMBERS 000026 DESCR LEGEND PTION HOURMETER OPTIONAL MODE SWI A C SW A C S BOOST 15 5 5 70A 70A 10A 8A C C CONDENSER CONDENSER CONDENSER CLUTCH CONDENSER CONDENSER CONDENSER CONDENSER CLUTCH RELAY CH ITCH 0 OP RELAY DELAYED PUMP RELAY RCUIT BREAKE RCUIT BREAKE RCUIT BREAKE RCUIT BREAKE RCUIT BREAKE R WATER PUMP R R R R RCUIT BREAKER R Y Y D EVAP MOTOR EVAP MOT
46. OR COND MOTOR COND MOTOR CLUTCH WATER PUMP 1 2 SWITCH 360 PSI RELAY 2 1 AND 2 1 2 RCUIT BREAKE FAN RELA FAN RELA FAN SPEE FAN MOTO FAN MOTO OVERLOAD OVERLOAD gt 1 2 1 2 gt CONDENSER SPEED RELAY 1 CONDENSER SPEED RELAY 2 DIODE DIODE DIODE DIODE DIODE DEFROST SWITCH COOLANT EVAPORA EVAPORA EVAPORA EVAPORA EVAPORA EVAPORA EVAPORA EVAPORA ENG FAULT HIGH LOW LOW POWER 1 2 3 4 5 COPT IONAL SWITCH COPTIONAL MOTOR 1 MOTOR 2 FAN RELAY 1 FAN RELAY 2 OVERLOAD 1 OVERLOAD 2 SPEED RELAY SPEED SWITCH FAN FAN RELAY PRESSURE SWITCH 425 PSI AMB PRESSURE SW EVAPORA EVAPORA ENT THERMOSTAT OPTIONAL ITCH OR OVERLOAD RELAY 1 OR OVERLOAD RELAY 2 TERMINAL BLOCK REHEAT COOLANT VALVE RECTI TERMI FIER NAL BLOCK C ELECTRONIC THERMOSTAT UNLOADER PRESSURE SWITCH 1 UNLOADER PRESSURE SWITCH 2 UNLOADER PRESSURE SWITCH 3 UNLOADER VALVE 1 UNLOADER VALVE 2 D wg No 68R M 35 1114 3 Rev C Sheet 1 of 2 5 10 POWER TERMINAL BLOCK
47. PERATURE lt SES gt Loo Er CFS GRD CFR14 TEMPERATURE H AUTO ORI oR2 KC 30 4 30 aj GRD TC10 SE REHEAT BPR B COOL O D3 85 Ke 1 Low 9 TINO D ca GRD TC 6 D E eo m SE GRD CFR24 4 6 8 Lear 10 3 4 1 Gem 5 OREHEAT Gi GRD EFR14 TA8 oar SII a res DI 85 86 1 OHEAT 3 GRD BPR86 L LOM AMBIANT ST ee Verum 955 CTH TC10 SH ITCH TAB NOTE TA TERMINAL BLOCK A 0 DRIVERS DASH TB TERMINAL BLOCK ENGINE COMPARTMENT TC TERMINAL BLOCK CON CONTROL PANEL 5 12
48. TRANSICOLD Bus Air Conditioning Unit Rearmount 68RM35 104 68RM35 604 68RM35 704 OPERATION AND SERVICE TRANSICOLD OPERATION AND SERVICE MANUAL BUS AIR CONDITIONING UNIT Rearmount 68RM35 104 68RM35 604 68RM35 704 mm UNITED TECHNOLOGIES S CARRIER TRANSICOLD TABLE OF 5 Section 1 DESCRIPTION LA Introduction ei aa te et re E dech Sen 12 Refrigeration System Component Specifications 1 3 El ctrical Specifications i coeno em ek i 14 Safety npe Re e Rete h apa e 15 System Operating Controls and Components 16 R heatCoolanbValV8 ee EORR eps 17 Moisture Liquid Indicator 18 Heater Coolant Flow Cycle s niati aaa 19 Air Conditioning Refrigerant Cycle 2 OPERATION 55 t en Seiya Tt wes Oe sua h rs mer io atout 2 1 Starting and Stopping Instructions 222 Pre trip nspection EE dE rater rea de a De P ER REIR 23 UNIT Operation Scu aa 23 1 Air Conditioning Operation Auto Mode 2 3 2 Air Conditioning Operation Reheat Mode 2 3 3 Air Conditioning
49. VALVE TH ELECTRONIC THERMOSTAT TSP TEMPERATURE SELECTOR POT UPS1 UNLOADER PRESSURE SWITCH 1 UPS2 UNLOADER PRESSURE SWITCH 2 UPS3 UNLOADER PRESSURE SWITCH 3 UV1 UNLOADER VALVE 1 UV2 UNLOADER VALVE 2 WPR WATER PUMP RELAY 02 NDICATES RELAY BOARD CONNECTION NDICATES WIRE GROUND INDICATES CUSTOMER SUPPLIED COMPONENTS 8 WIRING NDICATES A CONNECTION LUG SCREW ETC Ke NDICATES A CONNECTOR O4 NDICATES NORMALLY OPEN CONTACT NO NDICATES A NORMALLY CLOSED CONTACT LE NDICATES BUS INTERFACE CONNECTOR PIN LOCATION NDICATES RELAY BOARD TRACE 22 PIN CONNECTOR WIRING SIDE NOTES 1 2 3 4 UNIT SHOWN IS IN THE OFF POSITION RELAY CONTACTS SHOWN ARE IN THEIR NORMAL UNENERGIZED POSITION ADDRESS SYSTEM EXAMPLE CFR22 CM2A2 INDICATES A WIRE BETWEEN COND FAN RELAY 2 TERMINAL 2 AND COND MOTOR 2 TERMINAL 2 WIRE IDENTIFICATION SYSTEM COLORS WHITE DC CONTROL CIRCUIT GREEN GROUND YELLOW OPTIONAL CIRCUITS Figure 5 2 Electrical Schematic Wiring Diagram 5 M ode Selector Switch D wg No 68RM 35 1038 Rev A Sheet 1 of 2 5 4 TERMINAL BLOCK 1 MAIN POWER TERMINAL 24V DC TO DEFROST A Dj geg s 1 04 T4 A lt gt Cf WPR Jo MANUAL RESET 30 87 CIRCUIT BREAKER 016
50. backseat the filter drier inlet valve Disconnect lines Check refrigerant charge If the entire charge cannot be added a partial charge may be necessary b Adding a Partial Charge a Start the vehicle engine and allow unit to stabilize b Place the appropriate refrigerant container R 22 or 134a on the scale and connect charging hose from refrigerant cylinder vapor valve to the compressor suction service valve or the drop tube service port Purge charging line d Opentherefrigerant cylinder vapor valve idseat suction valve if used and monitor the weight of the cylinder to add the remaining refrigerant Disconnect cylinder 4 9 CHECKING THE REFRIGERANT CHARGE The following conditions must be met to accurately check the refrigerant charge 1 2 3 Bus engine operating at high idle U nit operation in cool mode for 15 minutes H ead pressure at least 250 psig for R 22 Systems or 150 psig for 134a systems It may be necessary to block condenser air flow to raise head pressure a Undertheabove conditions the system isproperly charged when the bottom receiver sight glass appears half full with refrigerant If the bottom sight glass is not half full add or delete refrigerant charge to the proper level 4 10 FILTER DRIER REMOVAL If the sight glass the receiver appears to be flashing or excessive bubbles are constantly moving through the sight glass the unit may have a low refrigerant charge or the fi
51. by openingthe valve clockwise 1 4 to 1 2 turn With 4 1 REFERENCE SECTION 2 1 None 4 1 a None 4 6 4 10 4 1 b None Replace Tighten None None 4 16 the valve stem midway between frontseated and back seated positions the suction or discharge line is open to both the compressor and the gauge connection To Discharge or Valve Cap from Suction Line zi CWE D WU S SS S Port to Gauge Valve Compressor Connection Stem Service Valve Backseated counterclockwise Service Valve Frontseated clockwise gt Figure 4 1 Suction or Discharge Service Valve 43 MANIFOLD GAUGE SET The manifold gauge set can be used to monitor system operation pressure add or remove refrigerant evacuate and equalize the system The manifold gauge in Figure 4 2 shows hand valves gauges and refrigerant openings When the manifold hand valves are backseated open the high and low side hoses are common with the center hose as well as each other When the low and high side valves are frontseated closed the high and low side hoses are isolated from each other and the center hose It is in the front seated closed position that system pressures can be monitored When both valves are open backseated pressure will cause vapor to flow from the high side to the low side across the compressor When only the low side valve is opened it is possible to add refrigerant in vapor form
52. cted air flow Blower running in reverse Dirty air filter Icing of coil Compressor valves defective NOTE Refer to 05G Compressor manual Form T 199 31 REFERENCE SECTION Check See Note Check Replace 1 4 Check 1 5 Check Reset 3 5 1 5 See Note Check 3 3 WWW amp 4 12 en TOO oO 4 9 Check Pressure Check Clean See Note 4 9 See Note Open Check Open 4 10 DRE 4 17 Clean See Note INDICATION TROUBLE POSSIBLE CAUSES 3 4 ABNORMAL NOISE AND VIBRATIONS 3 4 1 ABNORMAL NOISE Compressor Condenser or Evaporator fan 3 4 2 ABNORMAL VIBRATION Compressor Evaporator or Condenser fan Loose mounting bolts Worn bearings Worn or broken valves Liquid slugging Insufficient oil Clutch loose or rubbing Loose or defective Bearings Blade Interference Blade broken or missing Loose mounting bolts Bent shaft on motor Blade broken or missing 3 5 TEMPERATURE CONTROLLER MALFUNCTION Will not control Controller defective Sensor defective Defective wiring 3 6 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOW No evaporator air flow Motor defective Fan damage Brushes defective Return air filter dirty Fan Relays EFR1 or EFR2 defective Safety device open Wiring polarity incorrect 3 7 EXPANSION VALVE MALFUNCTION Low suction pressure with high superheat Low superheat and liquid slugging in compressor Fluctuating suc
53. ding the motor down and out from the fan blade and unit Remove blade e Using a adhesive secure the shaft key to the serviced motor shaft or fan hub slot e When installing the motor secure the fan blade above the shroud before mounting the motor Align the motor shaft through the fan blade hub and secure motor mounting bolts 4 9 f Position the fan blade 1 3 the height of blade below the shroud tighten the two retaining screws in the fan hub 1 2 Position 1 3 of blade height below shroud 5 Fan Blade 6 Shroud 7 Fan Blade Guard Condenser Coil Fan Blade Hub Retaining Set Screw 5 16 Ratchet Wrench BON Figure 4 10 Condenser Fan Motor Removal 4 16 SERVICING THE EVAPORATOR FAN BLOWER MOTOR ASSEMBLY a Removing and Disassembling 1 Switch the rear control switc
54. e 6 75 pints 3 2 liters Oil L evel Old Crankcase before S N 4994 Bottom to 1 4 of sight glass New Crankcase beginning S N 4994 Between M ax marks on crankcase A pproved Compressor Oils R 22 Calumet R efining Co R 030 Texaco SF 68 Witco 4G 5 Suniso A pproved Compressor Oils R 134a Castrol cematic SW 68C M obil EAL Artic 68 Emkarate R L 68H Thermostatic E xpansion Valve R 22 Units Superheat Setting 12to 14 F 6 7to 7 8 C M OP Setting 95 5 7 psig 6 7 0 49 R 134a Units Superheat Setting 10 F 5 6 C M OP Setting 53 9 4 psig 3 8 0 28 kg cm Low Pressure Switch LPS O pens at 6 3 psig 0 42 0 21 kg cm Closes at 25 5 psig 1 8 0 35 1 5 05G Compressor e High Pressure Switch HPS R 22 Units O pens at 425 10 psig 30 0 7 kg cm Closes at 300 10 psig 21 0 7 kg cm R 134a Units O pens at 300 10 psig 21 0 7 kg cm Closes at 200 10 psig 14 0 7 kg cm f Condenser Fan Speed Switch CFS R 22 Units O pensfor high speed 360 10 psig 25 0 7 kg cm Closes for Low Speed 285 gt 15 psig 20 x 0 7 R 134a Units O pensfor high speed 250 10 psig 18 0 7 Closes for Low Speed 190 15 psig 13 0 7 9 Condenser Fan Motor Bearing Lubrication Factory Lubricated additional grease not required H orsepower 0 8 hp 0 6 kw Full Load Amps FLA 18 amps Operating Speed Lo
55. e and the temperature of the refrigerant and forces it into the condenser tubes T he condenser fan circulatessurrounding air which is at a temperature lower than the refrigerant over the outside of the condenser tubes H eat transfer is established from the refrigerant inside the tubes to the condenser air flowing over the outside of the tubes The condenser tubes have fins designed to improve thetransfer of heat from the refrigerant gas to the air T his removal of heat causes the refrigerant to liquefy thus liquid refrigerant leaves the condenser and flowsto the receiver receiver serves as a liquid refrigerant reservoir so that a constant supply of liquid is available to the evaporator asneeded and asa storage space when pumping downthe system The receiver isequipped with a sight glass to observe the refrigerant for restricted flow and correct charge level Therefrigerant leavesthe receiver and flowsthrough moisture liquid indicator which indicates the moisture content of the refrigerant through the filter drier inlet valve and through a filter drier where an absorbent keeps the refrigerant clean and dry It then flows out of the filter drier and through the filter drier outlet valve The liquid then flows to an externally equalized thermostatic expansion valve which reduces pressure and temperature of the liquid and meters the flow of liquid refrigerantto the evaporator to obtain maximum use ofthe evaporator heat tran
56. e ohmmeter reading does not correspond with the pressure listed in Table 4 1 the switch is defective and should be replaced Table 4 1 Pressure Switch C ontinuity Check Ohmmeter Reading No Continuity Continuity Opens at Closes at R 22 Switches High Pressure HPS Low Pressure LPS Condenser Fan Speed CFS Unloader Pressure 1 UPS1 Unloader Pressure 2 UPS2 Unloader Pressure 8 UPS3 425 10 psig 6 3 psig 360 10 psig 66 2 psig 65 5 325 15 psig 300 10 psig 25 3 pig 285 15 psig 54 2 pig 50 3 psig 400 10 psig 134A Switches Pressure HPS Low Pressure LPS Condenser Fan Speed CFS Unloader Pressure 1 UPS1 Unloader Pressure 2 UPS2 Unloader Pressure 8 UPS3 300 10 psig 6 3psig 250 10 psig 35 2 psig 40 5psig 220 15 psig 200 10 psig 25 3psig 190 15 psig 26 2 psig 23 3 pig 270 10 psig 4 12 THERMOSTATIC EXPANSION VALVE The thermal expansion valve is an automatic device which maintains constant superheat of the refrigerant gas leaving the evaporator regardless of suction pressure The valve functions are automatic response of refrigerant flow to match the evaporator load and b prevention of liquid refrigerant enteringthe compressor Unless the valve is defective it seldom requires maintenance a Replacingthe Expansion Valve 1 Pump down the unit Refer to sectio
57. ed Compressor 4 184 Adding Oil to the Service Replacement Compressor 5 ELECTRICAL SCHEMATIC WIRING DIAGRAM Introduction afin i i eram t LIST OF ILLUSTRATIONS Figure 1 1 Unit Assembly Back View 1 2 Unit Assembly Inside View 1 3 Electrical Component 1 4 056 COMPRESSOR onte ees ee A eet sonat n o eoe 1 5 Reheat Coolant Valve 1 6 Heater Coolant Flow 1 7 Air Conditioning Refrigerant Cycle 2 1 Temperature Controller Sequence During Auto Mode 2 2 Temperature Controller Sequence During REHEAT Mode 2 3 Temperature Controller Sequence During Cooling 2 4 Temperature Controller Sequence During Vent Mode 2 5 Temperature Controller Sequence During H eat Mode 2 6 Automatic High Speed 2 2 2 7 Automatic Low Speed Heat 2 8 Automatic Low Speed Vent 4 1 Suction or Discharge Service Valve
58. ed operation and the unit is now operating in the low speed cooling mode When the vehicle s interior temperature rises to 7 F above the thermostat setpoint the H EAT COOL switch remains in the COOL position to keep the clutch relay energized But the HIGH LOW switch switches from LOW totheHIGH position which causesthe evaporator fan motors to change from low speed to high speed operation See figures 2 1 and 2 6 The unit now operates in the high speed cooling mode RISING TEMPERATURE 7 ABOVE SETPOINT HIGH SPEED COOL 5 F ABOVE SETPOINT LOW SPEED COOL 3 F ABOVE SETPOINT 1 F ABOVE SETPOINT SETPOINT SETPOINT 2 F BELOW SETPOINT LOW SPEED HEAT 3 F BELOW ETPOINT 5 F BELOW SETPOINT HIGH SPEED HEAT FALLING TEMPERATURE Figure 2 1 Temperature Controller Sequence During Auto M ode When the vehicle s interior temperature falls to 5 F above the thermostat setpoint the HEAT COOL switch remains in the COOL position to keep the clutch relay energized But the HIGH LOW switch switches from HIGH toLOW position which causesthe evaporator fan motors to change from high speed to low speed operation When the vehicle s interior temperature falls to 1 F above the thermostat setpoint the HEAT COOL switch will switch to a neutral position to de energize the clutch relay CR and the condenser fan motors CM 1 and CM 2 this will stop the flow of refrigerant and stop operation of the condenser fans
59. ed system method a Oil Pump M ethod L Connect an oil pump to a one U S gallon 3 785 liters refrigeration oil container Using the Robinair compressor oil pump Carrier Transicold P N 14388 is recommended When the compressor isin operation the pump check valve prevents the loss of refrigerant while allowing servicemen to develop sufficient pressure to overcome the operating suction pressure to add oil as necessary 2 Backseat suction service valve and connect oil charging hose to port Crack the service valve and purge the oil hose at oil pump A dd oil as necessary b Closed System M ethod In an emergency where an oil pump isnot available oil may be drawn into the compressor through the suction service valve CAUTION Extreme care must be taken to ensure the man ifold common connection remains immersed in oil at all times Otherwise air and moisture will be drawn into the compressor 1 Connect manifold gauge set Place center charging line into compressor oil container as shown in Figure 4 12 Slowly open discharge hand valve to purge line then close 2 Frontseat the suction service valve and place a jumper wire on the low pressure switch to by pass the switch 3 Start unit and pull crankcase pressure until suction pressure gauge indicates 5 inches hg Shut down unit 4 Crack open manifold valve and allow vacuum in compressor to draw oil slowly into compressor When level is just above one quarter glass
60. er starting Check tension and condition of V belt s Perform daily inspection Check condenser evaporator coils and air filters Check refrigerant hoses and compressor shaft seal for leaks Feel filter drier for excessive temperature drop across drier c Monthly Inspection and Maintenance Perform weekly inspection and maintenance 5 Check wire harness for chafing and loose terminals Clean evaporator drain pan hose Check fan motor bearings Check compressor mounting bolts for tightness Check fan motor brushes 42 SUCTION AND DISCHARGE SERVICE VALVES The suction and discharge service valves used on the compressor are equipped with matingflangesfor connec tion to flanges on the compressor These valves are provided with a double seat and a gauge connection which allows servicing of the compressor and refrigerant lines Turning the valve stem counterclockwise all the way out will backseat the valve to open the suction or discharge line to the compressor and close off the gauge connection normal operation the valve is backseated to allow full flow through the valve The valve should always be backseated when connecting the service man ifold gauge lines to the gauge ports Turningthe valve stem clockwise all the way forward will frontseatthe valveto close off the suction or discharge line to isolate the compressor and open the gauge connection To measure suction or discharge pressure midseatthe valve
61. eration When the vehicle interior temperature rises to 3 F belowthe setpoint the HIGH LOW switch switchesfrom HIGH to LOW position this causes the evaporator fan motors to change from high to low speed operation When the vehicle interior temperature rises to the setpoint the H EAT COOL switch switches from HEAT to COOL position this de energizes the BPR relay which de energizes the booster pump stopping the flow of hot water through the reheat coils The evaporator fan motors continue to operate on low speed RISING TEMPERATURE LOW SPEED COOL SETPOINT SETPOINT 2 F BELOW SETPOINT LOW SPEED HEAT 3 F BELOW SETPOINT 5 F BELOW SETPOINT HIGH SPEED HEAT FALLING TEMPERATURE Figure 2 5 Temperature Controller Sequence During HEAT Mode LEGENDS SYMBOLS AND NOTES FOR ELECTRICAL DIAGRAMS LEGEND SYMBOL DESCRIPTION ACHM HOURMETER COPTIONAL ACS A C SWITCH COFF ON ACSR1 A C STOP RELAY 1 ACSR2 A C STOP RELAY 2 BPR BOOST PUMP RELAY CBI 15 CIRCUIT BREAKER WATER PUMP RELAY CB2 35A CIRCUIT BREAKER EVAP MOTOR 2 CB3 35A CIRCUIT BREAKER EVAP MOTOR 1 AND 2 70A CIRCUIT BREAKER COND MOTOR 1 CB5 70A CIRCUIT BREAKER COND MOTOR 2 CBE 10A CIRCUIT BREAKER CLUTCH CFS CONDENSER FAN SPEED SWITCH 360 PSI CL CLUTCH CM1 CONDENSER FAN MOTOR 41 CM2 CONDENSER FAN MOTOR 2 CR CLUTCH RELAY D1 D27 DIODE 1 DIODE 27 DFS DEFROST SWITCH OPTIONAL ECS ENGINE COOLANT SWITCH OPTIONAL EMI
62. ergizing the control circuits of the R M 35 unit The switch is located on the driver s control panel Mode Switch ACM S The A C mode switch ACM S activates the cycling clutch vent heat reheat and auto modesof operation The switch is located on the driver s control panel Placing the switch in the COOL position energizes the clutch relay when the temperature controller issensing a need for more cooling Placingthe switch in the V ENT position operates the evaporator fans only Placing the switch in the HEAT position energizes the booster pump relay when the temperature controller is sensing a need for more heating Placingthe switch in the position energizesthe booster pump relay when the temperature controller is sensing that the coach is getting too cold The compressor clutch is always energized during the reheat mode When the switch the AU TO position the need for heatingor cooling is determined by the setpoint of the temperature controller and position of the evaporator speed switch ESS if installed Evaporator Speed Switch ESS Optional The evaporator speed switch ESS if installed is located on the driver s control panel The E 55 when in the LOW or HIGH position overrides the temperature controller switch W hen switchisinthe HIGH position the evaporator fansare operated at high speed at all times When in the LOW position the fans are operated at low speed at all times
63. h to the OFF position 2 Disconnect the wire leads to the junction box of the motor M ark theleadsfor proper reassembly It isnot necessary to disconnect the wire leads when moving the motor assembly to replace the heater coil 3 Remove motor mounting bolts to the bottom panel 4 Remove the four shroud mounting bolts Slide assembly out of the blower housing 5 Loosen the two blower hub set screws to remove blower Remove four shroud retaining boltsto the motor housing to remove shroud 6 To reassemble reverse the above procedure Position blower 1 1 16 inch from inside blower edge to shroud flange see Figure 4 11 1 2 3 7 REMOVAL 8 Bs J 9 L E T 1r DISASSEMBLING 1 1 16 T J ASSEMBLING 1 Blower Housing 6 Mounting Bolt 2 Fan Blower 7 Wire unction Box 3 Shroud 8 Shroud Motor 4 Shroud Mounting Retaining Bolt Bolt 9 Hub Set Screw 5 Evaporator Motor Figure 4 11 E vaporator Fan Blower Removal 4 16 1 Routine E xamination and Cleaning a At regular maintenance periods remove brush covers and clean and examine motor interior b Remove all foreign mate
64. he coolant valve requires no maintenance unless a malfunction to the internal parts or coil occurs This may be caused by foreign material such as dirt scale or sludge in the coolant system or improper voltage to the coil To service the valve includes replacement of the internal parts shown in Figure 4 9 or the entire valve There only three possible valve malfunctions coil burnout failure to open or failure to close Coil burnout may be caused by the following 1 Improper voltage 2 Continuous over voltage more than 1096 U nder voltage of more than 15 4 8 3 Incomplete magnetic circuit due to the omission of the coil housing or plunger 4 Mechanical interference with movement of plunger which may be caused by a deformed enclosing tube Failure to open may be caused by the following L Coil burned out or an open circuit to coil connections 2 Improper voltage Torn diaphragm Defective plunger or deformed valve body assembly Failure to close may be caused by the following 1 Defective plunger or deformed valve body assembly 2 Foreign material in the valve a Toreplace a burnout coil it is not necessary to drain the coolant from the system 1 Place the rear control switch in the OFF position 2 Disconnect wire leads to coil Remove coil retaining screw and nameplate Lift burned out coil from enclosing coil assembly and replace 5 Connect wire leads and test o
65. he filter drier momentarily Tighten the outlet flare nut using two open end wrenches j Immediately backseat fully close both service valve ports and replace valve caps k Test filter drier for leaks I Check refrigerant level 1 2 3 4 1 Filter Drier Outlet Liquid Line Valve 2 Valve Service Port 3 Flare Nut Figure 4 5 Filter Drier Removal 3 2 4 Filter Drier 5 Filter Drier Inlet Liquid Line Valve 5 4 5 4 11 PRESSURE SWITCHES recommended procedure for testing the High Pressure Switch HPS Low Pressure Switch LPS Condenser Fan Speed Switch CFS and Unloader Pressure Switches 2 amp 3 U PS2 amp U PS3 isto remove the the switch from the unit and bench tested as described in the following procedure All pressure switches are threaded into positive shut off connections schrader to allow easy removal and installation without pumping down or removing refriger ant from the unit All wire leads to the switches are quick disconnects The High Pressure switch black wire leads and Low Pressure switch red wire leads are located on the compressor T he Condenser Fan Speed switch gray wire leads and the U nloader Pressure switch 3 white wire leads are located on the discharge line above the curbside evaporator fan blower assembly The U nloader Pressure switch 2 tan wire leads
66. hicle interior temperature During the cool mode the HEAT COOL switch controls the operation of the clutch relay CR which in turn controls the operation of the clutch on the air conditioning compressor When the vehicle interior temperature rises to 3 F above the thermostat setpoint the H EAT COOL switch switches to the COOL position to energize the clutch relay which engagesthe compressor clutch and startsthe flow of refrigerant in the refrigerant cycle HIGH LOW switch remainsin the LOW position which keepsthe evaporator fan motors operating on low speed When the vehicle interior temperature rises to 7 above the thermostat setpoint HIGH LOW switch switches from LOW to HIGH position this causes the evaporator fan motorsto change from lowto high speed operation The HEAT COOL switch remains in the COOL position keeping the clutch engaged and refrigerant flowing See figure 2 6 When the vehicle interior temperature falls to 5 F above the thermostat setpoint the HIGH LOW switch switches from HIGH to LOW position which causesthe evaporator fan motors to change from high speed to low speed The HEAT COOL switch remains in the COOL position which keeps the compressor clutch energized and refrigerant flowing through the refrigerant cycle When the vehicle interior temperature falls to 1 F above the thermostat setpoint the H EAT COOL switch switchesto a neutral position thisde energizesthe clutch relay which i
67. ill flow from the liquid line valve to the cylinder H ead discharge pressure will drop g Monitor weight of the refrigerant cylinder to determine how much refrigerant is being removed Shut off cylinder valve when the scale weight has stabilized indicating the refrigerant flow into the cylinder has stopped the unit for afew more minutes to condense more liquid and raise head pressure NOTE Refrigerant will flow from the system to the cylinder until the pressures equalize It is possible to remove more refrigerant by cooling the refrigerant cylinder in a container of ice h Backseat the liquid line valve and remove cylinder hose i Service or replace the necessary component in the system NOTE When opening up the refrigerant system certain parts may frost Allow the part to warm to ambient temperature before dismantling This avoids internal condensation which puts moisture in the system 4 3 4 6 REFRIGERANT LEAK CHECK A refrigerant leak check should always be performed after the system has been opened to replace or repair a component To check for leaksin the refrigeration system perform the following procedure a Systems Without Refrigerant 1 If system is without refrigerant charge system with refrigerant to build up pressure between 30 to 50 psig 2 1 to 3 5 kg cm NOTES 1 It is recommended that the appropriate refrigerant used be used to pressurize the system 2 Under no circumstance
68. ions 5 10 LIST OF TABLES Table Page 1 1 Model Charts c Dekret det EM lose 1 1 1 2 U nloader Pressure Switch Settings 1 6 1 3 Safety DEVICES et dar A tbe 1 6 4 1 Pressure Switch Continuity 4 6 4 2 R 22 Temperature Pressure Chart 4 13 4 3 R 134a Temperature Pressure 4 14 SECTION 1 DESCRIPTION 11 INTRODUCTION This manual contains operating and electrical Data and service instructions for the 68RM35 bus air conditioning heating and vent systems shown in table 1 1 The 68R M 35 unit is a one piece system consisting of a condenser evaporator and heater coil assemblies The units are installed in the rear A C compartment of the bus These units interface with the bus s customer supplied compressor driver s switches and pump to provide a full air conditioning heating and ventilation system All control systems are powered by 24 vdc supplied by the bus battery and alternator or alternate source Operation of the 68RM35 units is controlled automatically by the temperature controller which maintainsthe vehicle sinterior temperature at the desired setpoint Table 1 1 M odel Chart Model Number Refrigerant GBRM35 104 Heal Coo 68RM35 604 Heat
69. is located on the suction line behind the curbside return air grille Ifthe switch does not function asdescribed below the switch is defective and should be replaced a Remove switch from the unit b Connectan ohmmeter across switch leads with no pressure applied to the switch A continuity reading should indicate a closed switch If the switch is good continue c Connect switch to a cylinder of dry nitrogen as shown in Figure 4 6 3 EE 1 Cylinder Valve 5 Bleed Off Valve Gauge 6 1 4 inch Connection Pressure Regulator 7 Nitrogen Cylinder Pressure Gauge 8 0 to 500 psig 0 to 36 kg cm High or Low Pressure Switch Ohmmeter Figure 4 6 Checking High Pressure Switch 4 6 WARNING Donotusea nitrogen cylinder without a pressure regulator Cylinder pressure is approximately 2350 psi 165 kg cm Do not use oxygen in or near a refrigeration system as an explosion may occur Back off regulator adjustment completely O pen the cylinder valve e Slowly open the regulator valve to increase the pressure to the applicable pressures listed in Table 4 1 open or close the switch If the ohmmeter reading does not correspond with the pressure listed in Table 4 1 the switch is defective and should be replaced f Close cylinder valve and release the pressure through the bleed off valve 5 the pressure drops the applicable switch will open or close If th
70. le proceed as follows E quipment Required 1 Appropriate evacuated returnable refrigerant cylinder preferably a 60 120 Ib net capacity may be used Refrigerant removal will be faster and more complete with the larger cylinder WARNING Do not use a disposable refrigerant container to store the refrigerant an explosion may occur 2 Gauge manifold set Equipment Required C ont d 3 Vacuum pump preferably 5 8 cu H or larger CTD P N 07 00176 01 4 Weight scale 0 to 100 Ib 0 to 46 kg range minimum 5 A standard 1 4 in charging hose To remove the refrigerant charge a Installamanifoldgaugesetasoutlinedinsection b Connect evacuated refrigerant cylinder to the liquid line valve at the inlet valve of the filter drier The service line to the liquid valve of the cylinder should be attached loosely Crack open the liquid line valve momentarily to purge service line at cylinder Tighten connection at cylinder C Place evacuated refrigerant cylinder on scale and note weight of empty cylinder L eave cylinder on scale d Frontseat liquid line valve at the inlet of the filter drier e Runtheunitin high speed cool with the condenser coil completely blocked off H ead pressure will quickly rise Stop the unit when the system pressure reaches 250 psig for R 22 systems or 150 psig for 134a systems using the rear control switch f Fully open the refrigerant cylinder liquid valve Liquid refrigerant w
71. lter drier could be partially plugged If a pressure drop across the filter drier isindicated or the moisture indicator may show an abnormal wet condition the filter drier must be changed a Check for arestricted filter Backseat the inlet and outlet valves of the filter drier and attach the gauge manifold set idseat both valve and start unit O bserve the pressure reading If a pressure drop of more than 10 psigisindicated the filter is plugged and must be changed b Pump down the system as outlined in section 4 4 c Turn the driver s A C switch and rear control switch the OFF position Placeanewfilter drier near the unit for immediate installation e Using two open end wrenches slowly crack open the flare nuts on each side of the filter drier After remaining refrigerant has escaped remove the filter drier CAUTION The filter drier may contain liquid refrigerant Slowly open the flare nuts and avoid contact with exposed skin or eyes f Remove seal caps from the new filter drier A pply a light coat of compressor oil to the flares g Assemble the new filter drier to lines ensuring that the arrow on the body of the filter drier points in the direction of the refrigerant flow refrigerant flows from right to left as viewed Finger tighten flare nuts h Tighten filter drier inlet line flare nut using two open end wrenches i Open the filter drier inlet liquid line valve slowly to purge t
72. lve settings 1 Remove insulation from sensor bulb and suction line if installed 2 Loosen one bulb clamp and make sure area under clamp is clean 3 Place the temperature thermocouple above par allel TXV bulb and tighten loosened clamp making sure both bulbs are firmly secured to suction line as shown in Figure 4 8 Place insulation around TXV bulb and thermocouple 4 Connect suction gauge to the service port located on the suction line near the valve 5 Set temperature selector to lowest setting Run unit for at least 20 minutes to stabilize the system 6 Using the temperature pressure chart Table 4 2 or Table 4 3 for the applicable refrigerant used deter mine the saturation temperature corresponding to the pressure taken at the suction service valve 7 Note the temperature of the suction gas at the sensor bulb 8 Subtract the saturation temperature determined in Step 6 from the average temperature measured in Step 7 The difference is the superheat of the suction gas 1 Suction Line end view 2 Clamp 3 Thermocouple 4 TXV Sensor Bulb Figure 4 8 Thermostatic E xpansion Valve Bulb and Thermocouple c Adjusting Superheat Refer to section 1 2 d for the superheat setting The thermostatic expansion valve used in this applica tion is externally adjustable The valve is preset at the factory and should not be adjusted unnecessarily 11 necessary to adjust the superheat proceed as follows 1 Rem
73. n 4 4 2 Remove left return air access panel 3 Remove insulation Presstite from expansion valve bulb and remove from suction line 4 Loosen flare nut and disconnect equalizer line from expansion valve 5 Remove flange screws and lift off power head and cage assemblies C heck for foreign material in valve body 6 Install new gaskets and assemble new cage and power head assemblies 7 Attach the sensor bulb just below center of the suction line 4 or 7 o clock position viewing from cross section to the suction line see Figure 4 8 Thisarea must be clean to ensure positive bulb contact Do not insulate the bulb until the superheat is measured 8 Fasten equalizer tube to expansion valve 9 Evacuate by placing vacuum pump on the com pressor suction service valve port or suction drop tube port located in the engine compartment 10 Open the inlet service valve to the filter drier Check refrigerant level Refer to paragraphs 4 5 and 4 9 11 Check superheat Power Head Cap Seal Flare Seal Retaining Nut Adjusting Stem Equalizer Connection Sensor Bulb Gasket Cage Assembly Body Flange Capscrew OY UL TOUS ES Lr Figure 4 7 Thermostatic E xpansion Valve 4 7 b To Measure Superheat NOTE When conducting this test the suction pressure must be at least 6 psig 42 kg cm below the expansion valve maximum operating pressure OP Refer to section 1 2 4 for applicable va
74. n turn de energizes the compressor clutch stoppingtheflow of refrigerant TheHIGH LOW switch remains the LOW position to keep the evaporator fan motors operating on low speed in the vent mode See figure 2 8 2 3 RISING TEMPERATURE HIGH SPEED COOL 7 F ABOVE SETPOINT 5 F ABOVE SETPOINT LOW SPEED COOL 3 F ABOVE SETPOINT 1 F ABOVE SETPOINT LOW SPEED VENT SETPOINT SETPOINT FALLING TEMPERATURE Figure 2 3 Temperature Controller Sequence During Cooling M ode 2 3 4 Vent Mode See figure 2 4 To operate in Vent mode place the A C control switch inthe VENT position In vent the evaporator fan motor speed is controlled on thermostat command to control vehicle interior temperature During the Vent mode the HIGH LOW switch controls the evaporator fan motor speed When the vehicle interior temperature falls to 5 F above the thermostat setpoint the HIGH LOW switch switches from HIGH to LO W this causes the evaporator fan motors to change from high to low speed operation The unit now operates on low speed vent See figure 2 8 When the vehicle interior temperature falls to 5 F below the thermostat setpoint the HIGH LOW switch switches from LOW to HIGH this causes the evaporator fan motors to change from low to high speed operation When the vehicle interior temperature rises to 3 F below the thermostat setpoint the HIGH LOW switch switches from HIGH to LOW position this causes the
75. ne coolant to flow through the heater coil See figure 1 6 At the same time the coolant valve is energized the booster pump customer supplied is activated to circulate the engine coolant through the inlet tube and header hose to the heater coil The coolant exits the coil and flows through the valve inlet hose With the coolant valve opened coolant flows through the valve outlet hose and coolant outlet tube back to the engine 3 4 Coolant Inlet Tube Header Inlet Hose Heater Coil Coolant Valve Inlet Hose Reheat Coolant Valve RCV Coolant Valve Outlet Hose Coolant Outlet Tube NO Figure 1 6 Heater Coolant Flow Diagram Revised 10 9 96 1 9 CONDITIONING REFRIGERANT CYCLE Therefrigeration cycle isthe same for air conditioning and reheating The refrigerant cycle is off during the vent mode and onlythe evaporator blowers operate to circulate air throughout the bus When air conditioning is selected the unit operates as a vapor compression system usingR 22 or R 134a as a refrigerant The main components of the system are the reciprocating compressor air cooled condenser coil thermostatic expansion valve and evaporator coil See figure 1 7 The refrigeration cycle begins when the compressor clutch is engaged The compressor raises the pressur
76. nit down to 2 to 4 psig 1 4 to 2 8 kg cm Frontseat discharge service valve and slowly bleed remaining refrigerant 4 Remove the oil drain plug on the bottom plate of the compressor and drain the proper amount of oil from the compressor Replace the plug securely back into the compressor 5 Repeat paragraph a 1 to ensure proper oil level NOTE Beforeopeningup any part of the system a slight positive pressure should be indicated on both gauges If a vacuumisindicated emit refrigerant by cracking receiver outlet valve momentarily to build up a slight positive pressure TEMPERATURE _F C 40 40 36 38 32 36 28 33 26 32 24 31 22 30 20 29 18 28 16 27 14 26 12 24 10 23 8 22 6 21 4 20 2 19 0 18 2 17 4 16 6 14 8 13 10 12 12 11 14 10 16 9 18 8 20 7 22 6 24 4 26 3 28 2 30 1 32 0 Psig Table 4 2 R 22 Temperature Pressure Chart PRESSURE Kg cm Bar 4 13 TEMPERATURE F Psig 60 5 63 3 66 1 69 75 0 81 4 88 1 91 5 102 5 110 2 118 3 126 8 135 7 145 154 7 164 9 175 4 186 5 197 9 209 9 222 3 235 2 248 7 262 6 277 0 291 8 307 1 323 6 341 3 359 4 377 9 396 6 415 6 434 6 PRESSURE Kg cm 4 25 4 45 4 65 4 85 5 27 5 72 6 19 6 43 7 21 7 75 8 32 8 91 9 54 10 19 10 88 11 59 12 33 13 11 13 91 14 76 15 63 16 54 17 49 18 46 19 48 20 52 21 59 22 75 24 0 25 27 26 57 27 88 29 22 30 56 Bar 4 1
77. ove the seal to gain access to the superheat adjusting stem see Figure 4 7 2 Turn the adjusting stem clockwise to compress the valve spring which will decrease refrigerant flow through the valve increasing superheat Turn the adjusting stem counterclockwise to decompress the valve spring which will increase refrigerant flow through the valve decreas ing superheat 3 When the unit has stabilized operation for at least 20 minutes recheck superheat setting 4 f superheat setting is correct replace stem cap remove gauge and thermocouple Insulate bulb and suction line 4 13 REMOVING THE HEATER COIL a Disconnect the bus battery b Remove evaporator motor and heater coil access panels C Open the air vent fitting at the top of the outlet header of the heater coil to bleed d Open the drain cock on the coolant inlet tube to drain coil e Remove both evaporator fan motor assemblies with mounting brackets refer to section 4 16 f Disconnect hoses from the coil g Disconnect and remove coolant solenoid valve assembly from the unit CAUTION If unit was recently operating be careful of re maininghot coolantin the hoses when disassem bling h Remove retaining bolts on each side of the coil assembly three each side Pull top of coil assembly forward and down to remove from unit i Reverse procedure for installing new heater coil assembly 4 14 SERVICING THE REHEAT COOLANT VALVE T
78. peration b To replace the internal parts of the valve 1 Place the rear control switch in the OFF position 2 Open the vent fitting at the top of the outlet header of the heater coil Drain coil by opening the drain cock on the inlet tube 4 Disassemble valve and replace defective parts 5 Assemble valve and connect coolant hoses c entire valve 1 Drain coolant system and disconnect hoses to valve as previously described 2 Disconnect wire leads to coil Remove valve assembly from bracket Install new valve and re connect hoses It is not necessary to disassembly the valve when installing 5 Fill system with coolant bleed air through the vent fitting 6 Connect wire leads and test operation 1 lt 2 10 1 Coil Retaining Screw 6 Plunger 2 Nameplate 7 Closing Spring 3 Coil Housing Assembly 8 Diaphragm 4 Enclosing Tube amp 9 O Ring Bonnett Assembly 10 Valve Body 5 Kick Off Spring Figure 4 9 Reheat Coolant Valve Assembly 4 15 REMOVING THE CONDENSER FAN MOTOR Whenremovingorinstallingthe condenser fan motor the fan blade must be remove to prevent any damage to the condenser coil a Remove fan blade guard b Using 5 16 ratchet or equivalent loosen the two retaining screws in the fan blade hub The fan blade will sit on the shaft of the motor c Remove the four motor mounting bolts from the bracket d Remove the motor by sli
79. r valves U V 1 and U V 2 respectively Energizing U V 2 will place the compressor in four cylinder operation Energizing UV1 will place the compressor in 2 cylinder operation s pressure rises the switch will re open Refer to table 1 2 for switch settings U nloader pressure switch U PS3 closeson pressurerise to energize unloader valve U V 2 E nergizingU V 2 will place the compressor in four cylinder operation As pressure drops the switch will re open Refer to table 1 2 for switch settings Energizing of unloader valve UV1 can also be accomplished through the controller LOAD UNLOAD Switch Relays Fault Relay FR The fault relay FR is plugged into the relay board on the electrical control panel located in the rear compartment of the unit See figure 1 3 The FR relayis energized during initial start up of the unit If the high or low pressure switch HPS or LPS opens due to unsafe operating conditions the fault relay FR de energizesand closesan internal set of FR contactsto energize the ACSR Stop Relays ACSR 1 and ACSR2 TheA C stop relays ACSR 1 and ACSR 2 are plugged into the relay board on the electrical control panel located in the rear compartment of the unit See figure 1 3 The ACSR relay is a time delay relay that energizes the stop light when activated by the fault relay FR To restart the unit and turn the stop light off the switch must be toggled off and on
80. re Low ONT RR 1 6 Opens at 15 amps Opens at 40 amps Opens at 40 amps Opens at 60 amps Opens at 60 amps Opens at 10 amps R 22 Units Opens at 425 10 psig 30 Closes at 300 10 psig 21 R 134a Units Opens at 300 10 psig 21 0 7 kg cm Closes at 200 gt 10 psig 14 0 7 kg cm R 22 and R 134a Units Opens at 6 3 psig 0 42 0 21 kg cm Closes at 25 5 psig 1 8 0 35 kg cm 0 7 kg cm 0 7 kg cm 15 SYSTEM OPERATING CONTROLS AND COMPONENTS a Temperature Controller Thermostat The temperature controller is a thermostat that senses and controls the vehicle interior air temperature The desired interior temperature setpoint of the controller is manually set with the temperature selector located on the electrical control panel See figure 1 3 The controller s temperature sensor monitors the bus interior temperature at the return air section of the unit and controls the operation function of the system to maintain temperature at the desired setpoint The controller regulatesthe operation of the unit with three interior switches LOAD UNLOAD LOW HIGH and HEAT COOL The LOAD UNLOAD switch controls the compressor unloaders the LOW HIGH switch controls the evaporator fan speed the HEAT COOL switch establishes heating or cooling operating mode b Manual Switches o o Switch ACS The A C switch ACS activates the air conditioning heating or vent modes of operation by en
81. relay circuit is always energized When the vehicle interior temperature falls to 5 F above the thermostat setpoint the HIGH LOW switch switches from HIGH to LOW position this causes the evaporator fan motors to switch from high speed to low speed operation When the vehicle interior temperature falls to 2 F below the thermostat setpoint the H EAT COOL switch switches to the H EAT position see figure 2 2 and figure 2 7 to energize the booster pump relay BPR water pump relay WPR and the reheat coolant valve RCV this allows hot water to start flowing through the heater coils The clutch relay is still energized and the clutch is still engaged allowing refrigerant to flow through refrigerant cyde The HIGH LOW switch is still in the LOW 2 2 position keeping the evaporator fan motors running on low speed When the vehicle interior temperature falls to 5 F below the thermostat setpoint the HIGH LOW switch switches to the HIGH position this causes the evaporator fan motors to change from low speed to high speed operation The HEAT COOL switch remains in the HEAT position which keeps booster pump relay water pump relay and the reheat control valve energized See figure 2 7 When the vehicle interior temperature rises to 3 F below the thermostat setpoint the HIGH LOW switch switchesto the L OW position this causesthe evaporator fan motors to change from high speed to low speed operation The HEAT COOL switch remains in
82. rial such as dirt and carbon dust from with dry compressed air Clean by suction if possible to avoid blowing foreign matter into the motor Confirm free moving brushes to prevent binding 4 10 Examine brush wear and general condition If brushesare broken cracked severely chipped or worn to 1 3 the length of a new brush replace them Refer to section 4 16 2 e Examine the condition of the brush springs A discolored spring is a sign of overheating which may weaken the spring in which case the spring should be replaced f Observethe condition of the commutator and the armature coils that are visible 4 16 2 Brush Replacement If brushes are broken cracked severely chipped or worn to 1 3 their original length replace the brush lead assembly a Remove brush covers b With fingersor suitable hook lift the brush spring end up so the brush may slide up and out of the holder Loosen the brush screw to remove the brush shunt terminal Remove brush To replace lift brush spring and place brush in holder Position spring end on top of the brush d Connect the brush shunt terminal to its proper crossover with the brush screw loosely e Assure positioning of brush to permit the brush shunt to travel freely in the holder slot asthe brush wears If it hangs up commutator damage and motor failure will result f Tighten the brush screw 4 17 REPLACING THE RETURN AIR FILTERS The return air filter
83. s are located in front of the evaporator coil A ccessto the filtersisthrough the return air opening inside the bus The filters should be checked periodically depending on operating conditions for cleanliness dirty air filter will restrict the air flow over the evaporator coil This could cause insufficient cooling or heat and possible frost build up on the coil Remove filters as follows a Turn the rear control switch to OFF b Remove the two return air grille C Loosen the filter retaining clips d Pull the first filter forward and out through the return air opening e Slide the second filter past the holding channel to the right position and remove f Repeat the above step with the third filter g Reverse the procedure for installing the new filters 4 18 COMPRESSOR 4 18 1 Replacing the Compressor Removing 1 If compressor is inoperative and refrigerant pres sure still exists frontseat the suction and discharge service valves to isolate most of the refrigerant in the system from the compressor If the compressor runs pump down the compressor by frontseating the suction service valve until the pressure drops to 1 psig then stop the unit 2 Slowly release compressor pressure to a recovery system 3 Remove the suction and discharge service valves and disconnect the high and low pressure switches H PS amp LPS 4 Loosen the compressor to allow removal of all belts from the compressor 5
84. sfer surface The low pressure low temperature mixture of liquid and vapor refrigerant that flows into the evaporator tubes is colder than the air that is circulated over the evaporator tubes by the evaporator blower Heat transfer is established from the evaporator air flowing over the tubes to therefrigerant insidethetubes The evaporator tubes have aluminum fins to increase heat transfer from the air to the refrigerant T he cooler air is then circulated to the interior of the bus by the evaporator blowers The transfer of heat from the air to the low temperature liquid refrigerant in the evaporator causesthe liquid to vaporize This low temperature low pressure vapor passes through the suction line back to the compressor The low pressure refrigerant vapor is now drawn into the compressor where the cycle repeats 1 10 4 gt d 12 gt gt 1 Die R 1 Compressor 2 Discharge Line 3 Discharge Line Check Valve 4 Condenser Col 5 Receiver 6 Moisture liquid Indicator 7 Filter Drier Inlet Service Valve 8 Filter Drier 9 Filter Drier Outlet Service Valve 10 Thermostatic Expansion Valve 11 Evaporator Coil
85. sro rev kb CB2 40A EFR2 sech HIGH H Fo 4 MANUAL RESET 1 2 CIRCUIT BREAKER AI CB3 40A 1 EFRI A2 M GRO o4 Fo 3X MANUAL RESET 1 2 CIRCUIT BREAKER CBS m AI ESR 1 CERI HIGH 15 GRO Lo 2 52 TI MANUAL RESET 1 2 NS CIRCUIT BREAKER 2 CRT 4 GRD SEE NOTE 3 4 HIGH 1 CFR2 GRD H Fo 2 52 MANUAL RESET 1 2 2 1 5 CIRCUIT BREAKER een 10 1 3 J8 TI MANUAL RESET CIRCUIT BREAKER ENGINE COOLANT 24 VOLTS el SWITCH Occo D L L Es J R lt E2 K lt lt lt gt HPS OPEN P RISE 425 10 CLOSE P DROP 300410 LPS OPEN P DROP 6 3 CLOSE P RISE 2545 J5 680 2 CLOSE P DROP 50 5 1 5 OPEN P RISE 6152 F2 lt oO 1 NI UPS2 63 i RARES UPSI UPS1 TEMPERATURE SELECTOR TSP 04 3 6 Nuni3s YOSNIS 323393 Le 805836 373343 305435 05 06 GRD gt P gt 08 po Henu FREEZE O ELECTRONIC THERMOSTAT
86. t by depressing the breaker button when opened When the high pressure switch HPS or low pressure switch LPS opens and unit operation stops place the driver sA C switch to the OFF position and back to theON position to reset the A C stop relay and de energize the A C stop light Table 1 2 Unloader Pressure Switch Settings UNLOADER PRESSURE SWITCH C ontacts Open Close Settings psig kg cm Refrigerant Load Up Unload Load Up Unload Load Up Unload Opens Closes Opens Closes Opens Closes 66 2 54 2 61 2 4 6 0 14 3 8 0 14 4 3 0 14 31 2 23 2 2 2 0 14 R 134a 35 2 26 2 2 5 0 14 1 8 0 14 51 2 400 10 3 6 0 14 28 gt 0 7 270 15 19 1 325 15 23 1 220 15 1 6 0 14 19 1 Table 1 3 Safety Devices UNSAFE CONDITION SAFETY DEVICE DEVICE SETTING Excessive current draw by the booster pump motor Excessive current draw by evaporator fan motor no 1 Excessive current draw by evaporator fan motor no 2 Excessive current draw by condenser fan motor no 2 Excessive current draw by condenser fan motor no 1 Excessive current draw by clutch High system pressure Circuit Breaker CB1 Manual Reset Circuit Breaker CB2 Manual Reset Circuit Breaker CB3 Manual Reset Circuit Breaker CB4 Manual Reset Circuit Breaker CB5 Manual Reset Circuit Breaker CB6 Manual Reset High Pressure Switch HPS Automatic Reset Low system pressu
87. the HEAT position keeping the booster pump relay water pump relay and the reheat coolant valve energized When the vehicle interior temperature rises to the thermostat setpoint the HEAT COOL switch switchesto the COOL position this de energizes the booster pump relay water pump relay and the reheat coolant relay stopping the flow of hot water through the reheat coils TheHIGH LOW switch remainsin the LOW position to keep the evaporator fan motors running at low speed Also the clutch and condenser fan relays remain energized When the vehicle interior temperature rises to 7 above the thermostat setpoint the HIGH LOW switch switches to the HIGH position this changes the evaporator fan motors from low speed to high speed operation The clutch and condenser fan relays remain energized keeping refrigerant flowing through the refrigerant cycle RISING TEMPERATURE HIGH SPEED COOL 7 F ABOVE SETPOINT 5 F ABOVE SETPOINT LOW SPEED COOL SETPOINT SETPOINT 2 F BELOW SETPOINT LOW SPEED HEAT 3 F BELOW SETPOINT 5 F BELOW SSES Ee HIGH SPEED FALLING TEMPERATURE Figure 2 2 Temperature Controller Sequence During REHEAT Mode 2 3 3 Air Conditioning Operation Cool Clutch Cycling M ode See figure 2 3 To operate in cool clutch cycling mode Place the A C control switch in the COOL position In cool the compressor clutch is energized de energized thermostat command to control ve
88. the unit See figure 1 3 This relay will energize when temperature switch SW 2 calls for low speed evaporator fan operation in the HEAT mode When energized the internal contacts will close to start low speed evaporator fan operation On units with Rotron motors evaporator fan motor speed control is accomplished internally Condenser Fan Relays CFR1 and CFR2 Not Installed on Units with Rotron M otors The condenser fan relays CFR1 and CFR2 are installed on the electrical control panel located in the rear compartment of the unit See figure 1 3 When the air conditioning switch A CS isplaced in the ON position and thetemperature controller iscallingfor cooling CFR 1and CFR2 are energized When energized a set of internal land 2 contacts are closed to start the condenser fan motors The low ambient thermostat LATH if installed must be closed to energize the condenser fan relays Condenser Speed Relay CSR1 Not Installed on Units with Rotron M otors The condenser speed relay CSR 1 isinstalled on the electrical control panel located in the rear compartment of the unit See figure 1 3 This relay is energized at the same moment that the air conditioning switch ACS is placed inthe ON position provided thatthe condenser fan speed switch CFS is in the closed position If the condenser coil pressure reaches the CFS switch cutout setting the CFS switch will open to de energize condenser speed relay
89. tion pressure Low refrigerant charge Wax oil or dirt plugging valve orifice Ice formation at valve seat Superheat setting too high Power assembly failure Loss of bulb charge Broken capillary Loose bulb Superheat setting too low Ice holding valve open Foreign material in valve Pin and seat of expansion valve eroded or held open by foreign material Broken capillary Improper bulb location or loose bulb installation Low superheat setting NOTE Refer to 05G Compressor manual Form T 199 32 REFERENCE SECTION Check See Note See Note 3 7 4 18 2 Check Check Adjust Replace Check Check Check Replace Motor Check Replace Replace Check 4 16 4 16 4 16 Check Check 1 4 Check 5 1 4 9 Check 4 7 4 12 Replace Replace 4 12 Check 4 12 4 12 4 12 INDICATION TROUBLE POSSIBLE CAUSES 3 8 NO OR INSUFFICIENT HEATING Insufficient heating Dirty or plugged heater coil or filter Coolant valve malfunction or plugged Low coolant level No heating Coolant valve malfunction or plugged Controller malfunction Booster relay or pump malfunction Safety device open NOTE Refer to 05G Compressor manual Form 199 3 3 REFERENCE SECTION Check Check Check Check 3 5 Check 1 4 SECTION 4 SERVICE WARNING BEWARE OF ROTATING FAN BLADES AND UNANNOUNCED STARTING OF FANS 4 1 MAINTENANCE SCHEDULE UNIT OPERATION o ORATION a Daily Maintenance Pre trip inspection aft
90. w 1600 rpm High 1800 rpm Voltage 24 vdc h LowAmbient Switch LATH Opensat 45 5 7 3 2 8 Closes at 55 5 12 9 2 8 Engine Coolant Switch ECS Customer Supplied j Coolant Valve O ptional k 05G Compressor Electric Unloaders Pressure Switches UPS1 UPS2 amp UPS3 See Table 1 2 for settings Revised 10 9 96 1 3 ELECTRICAL SPECIFICATIONS a Evaporator Blower M otor Bearing Lubrication Factory Lubricated additional grease not required Horsepower 0 60 0 45 kw Full Load Amps FLA 18 amps O perating Speed Low 900 rpm High 1800 rpm Voltage 24 vdc b Condenser Fan M otor Bearing Lubrication Factory Lubricated additional grease not required H orsepower 0 8 hp 0 6 kw Full Load Amps FLA 18 amps O perating Speed L ow 1600 rpm High 1800 rpm Voltage 24 vdc 1 4 SAFETY DEVICES System components are protected from damage caused by unsafe operating conditions with safety devices listed in table 1 3 If the high pressure switch HPS or low pressure switch LPS opensdueto unsafe operating conditions the A C operation will automatically stop The A C stop light will illuminate to indicate an unsafe condition The evaporator blower motors will continue to operate to circulate air throughout the bus During any mode of operation the evaporator or condenser motors will stop if excessive current draw is sensed by circuit breakers All breakers must be manually rese
91. witch in the AUTO position In the Auto mode the temperature controller determines at what points coolingor heating are required to regulate vehicle interior temperature Thedriver sair conditioningswitch A CS isplacedin the ON position to activate the Auto mode of operation With the ACS switch in the ON position 24 volts is supplied to the evaporator fan motors EM 1 and EM 2 and the temperature controller or thermostat TH 2 1 When the vehicle s interior temperature rises to 3 F below the thermostat setpoint the H EAT COOL switch remains in the heat position But The HIGH LOW switch switchesfrom H IG H to LOW position thiscauses the evaporator fan motors to change from high to low speed operation When the vehicle s interior temperature rises to the thermostat setpoint the H EAT COOL switch switchesto a neutral position and unit now operates in the vent mode The HIGH LOW switch remains in the LOW position and the evaporator fan motors remain in low speed operation When the vehicle s interior temperature rises 3 F above the thermostat setpoint the H EAT COOL switch switches to the COOL position to energize the clutch relay CR through the closed contacts of the low ambient thermostat LATH if supplied this will start the refrigerant flow cycle See figure 1 7 Condenser fan motors CM 1 and 2 are also energized to start the condenser fans in low speed operation The evaporator fan motors remain in low spe

Bus Air Conditioning Unit - North America Transport Air Conditioning

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