Carrier DM-4 Power Pack Manuel de service

Model68RF-50ArticulatedCoachT- 269Bus AirConditioningUnit

1-6Revised 10-9-9612345 67 1011 12 131415161718 19202123 24252627282930313233221234 689 11 14151617 18 19202123 2425262728293031331. Boost Pump Relay

1-71.2 REFRIGERATION SYSTEM COMPONENTSPECIFICATIONSa. Refrigeration ChargeR-22 & R-134a:16lb.(7.2 kg)b. CompressorModel: 05KNo. of Cylinders: 4Wei

1-8Revised 10-9-961.3 ELECTRICAL SPECIFICA TIONSa. Evaporator Blower MotorEvaporator MotorField WoundPermanentMagnetBearing LubricationFactory Lubrica

1-91.5 SYSTEM OPERATING CONTROLS ANDCOMPONENTSa. Temperature Controller (Thermostat) (TH)The Temperature Controller (TH) is a thermostatthat senses an

1-10Revised 10-9-96e. Relays (See Figure 1-4 or Figure 1-5)Fault Relay (FR)The Fault Relay (FR) is located on the electricalcontrol panel in the retur

1-111.6 REFRIGERATION FLOW CYCLE(See Figure 1-6)The refrigeration system contains R-22 or R134arefrigerant. The refrigeration cycle is the same for ai

1-12Revised 10-9-961. Evaporator Coils2. Inline Sight Glass3. Low Pressure Service Port4. High Pressure Service Port5. Expansion Valves6. Liquid Line

1-131.7 REHEAT COOLANT VALVE (RCV)The Reheat Coolant Valve (RCV) is located in theevaporatorsection of the unit on the roof of the bus (seeFigure 1-1)

2-1SECTION 2OPERATION2.1 ST AR TING AND STOPPING INSTRUCTIONSa. Starting the Front Unit1. Refer to Power Pack operation manual,Form T-270 before start

2-2Figure 2-1. Front Unit --- TemperatureContro ll er Sequ enceDuring POWER PACK CoolingRisingTemperatureF allingTemperature+4_FAboveSetpoint+2_FAbove

Carrier Transicold Division, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221SERVICE MANUALOPERATION ANDBUS AIR CONDITIONING UNITMODEL68RF-50A

2-3Fi gure 2-3. Rear Unit --- Temper atureContro ll er Sequ enceDuring REHEAT CoolingRisingTemperatureF allingTemperatureUnloadedCool With ReheatUnloa

2-4Energized CircuitDe-energized CircuitFigure 2-5. Rear Unit CYCLING CLUTCH, Air Conditioning --- High Speed, Semi-Unloaded (3˚FAboveSetpoint)

2-5Energized CircuitDe-energized CircuitFigure 2-6. Rear Unit CYCLING CLUTCH, Air Conditioning Vent Mode --- High Speed (Below 1˚FAboveSetpoint)

2-6Energized CircuitDe-energized CircuitFigure 2-7. Rear Unit REHEAT, Air Conditioning Operation --- High Speed, Semi-Unloaded (Above Setpoint)

2-7Energized CircuitDe-energized CircuitFigure 2-8. Rear Unit R EHEAT, A/C with Reheat Mode --- High Speed, Semi-Unloaded (2˚F Below Setpoint)

2-8Figure 2-9. Rear Unit Heat Operation --- Low Speed Mode (2˚F Below Setpoint)Energized CircuitDe-energized Circuit

2-9Energized CircuitDe-energized CircuitFigure 2-10. Rear Unit Heat Operation --- Low Speed Vent Mode (At Setpoint)

2-10Energized CircuitDe-energized CircuitFigure 2-11. Front Unit --- COOL

2-11Energized CircuitDe-energized CircuitFigure 2-12. Front Unit --- HEAT

SECTION 3TROUBLESHOOTING3-1INDICATION/ REFERENCETROUBLE POSSIBLE CAUSES SECTION3.1 UNIT WILL NOT COOLCompressor will not run V-Be lt broke or defectiv

iTABLE OF CONTENTSSection Page1 DESCRIPTION 1-1...1.1 Introduction 1-1...

INDICATION/ REFERENCETROUBLE POSSIBLE CAUSES SECTION3-23.3 ABNORMAL PRESSURE CONTINUEDLow suction pressure Suction service valve partially closed Open

INDICATION/ REFERENCETROUBLE POSSIBLE CAUSES SECTION3-33.6 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOWNo evaporator ai r flow Motor burnout 4.18Fan

4-1SECTION 4SERVICEWARNINGBEWARE OF ROTATING FAN BLADES ANDUNANNOUNCED STARTING OF FANS.4.1 MAINTENANCE SCHEDULEUNITOPERATIONREFERENCEON OFFOPERATIONR

4-2handvalvesarebackseated(open),thehighand lowsidehoses are common with the center hose as well as eachother.Whenthelowandhighsidevalvesarefrontseate

4-35. A standard 1/4 in. charging hose.To remove the refrigerant charge:a. Install a manifold gauge set as outlined insection 4. 3.b. Connect evacuate

4-4PacklessValve3/8 FlareFittings (4)1/2 Flare FittingTubeStock1 --- 1/ 2 i n.PacklessValve1/8 NPTFittings1/8 NPTFitting (2)1/4 FlareFitting1/2 FlareF

4-523 451. Condenser Coils2. Filter-Drier Outlet Service Valve3. Filter-D rier4. Receiver Outlet Valve5. Receiver6. Thermostatic Expansion Valves7. Hi

4-63. Head pressure at least 250 psig for R-22systems or 150 psig for 134a systems.(It may be necessary to block condenserair flow to raise head press

4-7should indicate a closed switch. If the switch is good,continue.c. Connect switch to a cylinder of dry nitrogen asshowninFigure4-7.1. Cylinder Valv

4-87. Attach the sensor bulb just below center of thesuction line (4 or 7 o’clock position viewing from crosssectiontothesuctionline,seeFigure 4-9).Th

iiTABLE OF CONTENTS (CONT’D)Section Page4 SERVICE (CONT’D) 4-1...4.16 Servicing the Liquid Line Sole

4-9f. Reverse procedure for installing new heater coilassembly.4.14 REPLACEMENT OF EVAPORATOR COILa. Ifrefrigerantremainsinthesystem,performalowside p

4-10123456781091. Coil Retaining Screw2. Nameplate3. Coil Housing Assembly4. Enclosing Tube &Bonnett Assembly5. Kick-Off Spring6. Plunger7. Closin

4-117. Connect wire leads and test operation.123456781. Snap Cap2. Coil Assembly3. Enclosing TubeAssembly4. Plunger Assembly5. Gasket6. Piston Assembl

4-12d. Remove the filte r from the return air grille.e. Reverse the procedure for installing the newfilters.4.20 COM PRESSOR4.20.1 Replacing the Compr

4-13service valve and purge the oil hose at oilpump. Add oilas necessary.b. Closed System MethodIn an emergency where an oil pump is not available,oil

4-14Table 4-2. R-22 Temperature-Pressure ChartTEMPERATURE PRESSURE TEMPERATURE PRESSURE_F _CPsigKg/cm@ Bar _F _CPsigKg/cm@ Bar---40 ---40 .6 .04 .04 3

4-15Table 4-3. R-134a Temperature---Pressure ChartBOLD NO. = Inches Mercury Vacuum (cm Hg Vac)TemperaturePressure Temperature Pressure_F _C Psig Kg/cm

5-1SECTION 5ELECTRICAL5.1 INTRODUCTIONThissectionincludes electricalwiringschematicsfor Model68RF-50. The schematics shownin thissection are forR-22 r

5-2Figure 5-1. Electrical Wiring Schematic Diagram --- Rear (68RF50 with Permanent Magnent Motors)Dwg. No. C-070-913 Rev C (Sheet 1 of 2)

5-3ABCD678Figure 5-1. Electrical Wiring Schematic Diagram --- Rear (68RF50 with Permanent Magnent Motors)Dwg. No. C-070-913 Rev C (Sheet 2 of 2)

1-1SECTION 1DESCRIPTION1.1 INTRODUCTIONThis manual contains Operating and Electrical Data,and Service Instructions for the 68RF50 AirConditioning, Hea

5-4Figure 5-2. Electrical Wiring Schematic Diagram --- Front (68RF50 with Permanent Magnet Motors)Dwg. No. D-070-912 Rev D (Sheet 1 of 2)

5-5ABCD678Figure 5-2. Electrical Wiring Schematic Diagram --- Front (68RF50 with Permanent Magnet Motors)Dwg. No. D-070-912 Rev D (Sheet 2 of 2)

5-6Figure 5-3. Electrical Wiring Schematic Diagram --- Rear (68RF50 with Field Wound Motors)Dwg. No. D-070-776 Rev B (Sheet 1 of 2)

5-7ABCD678Figure 5-3. Electrical Wiring Schematic Diagram --- Rear (68RF50 with Field Wound Motors)Dwg. No. D-070-776 Rev B (Sheet 2 of 2)

5-8Figure 5-4. Electrical Wiring Schematic Diagram --- Front (68RF50 with Field Wound Motors)Dwg. No. D-070-775 Rev B (Sheet 1 of 2)

5-9ABCD678Figure 5-4. Electrical Wiring Schematic Diagram --- Front (68RF50 with Field Wound Motors)Dwg. No. D-070-775 Rev B (Sheet 2 of 2)

1-2Revised 10-9-96131. Liquid Line Solenoid Valve (LLS)2. Reheat Coolant Valve (RCV)3. High Pressure Service Port4. In-line Sight glass5. Hot Water Ou

1-31. Condenser Coil2. Condenser Fan Motor3. Discharge Check Valve4. DischargeLineValve5. Ambient Air Switch6. Liquid Line7. Filter-Drier Outlet Va lv

1-4Revised 10-9-961. Control Relay #12. Control Relay #23. Terminal Block “C” (TC)4. Condenser Speed Relay #1 (CSR1)5. Circuit Breaker (CB9) --- 20 Am

1-524. Boost Pump Relay (BPR)25. A/C Relay (ACR)26. A/C R elay #2 (ACR2)27. Heat Relay (HR)28. Heat Relay #2 (HR2)29. Terminal Block “C” (TC)30. Fault