Carrier DM-4 Power Pack- Manuals

1-5 24. Boost Pump Relay (BPR) 25. A/C Relay (ACR) 26. A/C Relay #2 (ACR2) 27. Heat Relay (HR) 28. Heat Relay #2 (HR2) 29. Terminal Block “C” (TC) 30. Fault Relay (FR) 31. Run Relay (RR) 32. Control Relay (CR) 33. Rectifier #1 (REC1) 34. Rectifier #2 (REC2) 35. A/C Stop Relay (ACSR) 36. Reheat/Cycle...

1-8 Revised 10-9-96 1.3 ELECTRICAL SPECIFICATIONSa. Evaporator Blower Motor Evaporator Motor Field Wound Permanent Magnet Bearing Lubrication Factory Lubricated (additional grease not required) Horsepower 0.25/0.5 0.5 Full Load Amps (FLA) 9.3/21 18 Operating Speed (RPM) 1500/2000 2000 Voltage 27vdc ...

1-11 1.6 REFRIGERATION FLOW CYCLE (See Figure 1-6) The refrigeration system contains R-22 or R134a refrigerant. The refrigeration cycle is the same for air conditioning and heating (during reheat mode). The refrigerant cycle is off during vent only mode; only the evaporator blowers operate to circul...

1-13 1.7 REHEAT COOLANT VALVE (RCV) The Reheat Coolant Valve (RCV) is located in the evaporator section of the unit on the roof of the bus (see Figure 1-1). RCV is an electrically operated solenoid valve controlled by thermostat command. RCV controls the coolant flow to the heater coil during Heatin...

2-1 SECTION 2 OPERATION 2.1 STARTING AND STOPPING INSTRUCTIONSa. Starting the Front Unit 1. Refer to Power Pack operation manual, Form T-270 before starting.2. Once the Power Pack is started, the unit automatically switches to COOL mode. b. Starting the Rear Unit 1. Start the vehicle engine.2. Switc...

2-4 Energized Circuit De-energized Circuit Figure 2-5. Rear Unit CYCLING CLUTCH, Air Conditioning --- High Speed, Semi-Unloaded (3˚F Above Setpoint)

4-3 5. A standard 1/4 in. charging hose. To remove the refrigerant charge: a. Install a manifold gauge set as outlined in section 4.3. 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 shoul...

4-5 2 3 4 5 1. Condenser Coils 2. Filter-Drier Outlet Service Valve 3. Filter-Drier 4. Receiver Outlet Valve 5. Receiver 6. Thermostatic Expansion Valves 7. High Pressure Service Port 8. Low Pressure Service Port 9. Discharge Service Valve 10. Suction Service Valve 11. Compressor 12. Reclaimer 13. V...

4-6 3. Head 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. Under the above conditions, the system is properly charged when the bottom receiver sight glass indicator ball is floating. If the bottom...

4-7 should indicate a closed switch. If the switch is good, continue. c. Connect switch to a cylinder of dry nitrogen as shown in Figure 4-7. 1. Cylinder Valve and Gauge 2. Pressure Regulator 3. Nitrogen Cylinder 4. Pressure Gauge (0 to 500 psig = 0 to 36 kg/cm @ ) 5. Bleed-Off Valve 6. 1/4 inch Con...

4-9 f. Reverse procedure for installing new heater coil assembly.4.14 REPLACEMENT OF EVAPORATOR COIL a. If refrigerant remains in the system, perform a low side pump down, removing all refrigerant from the evaporator coils. b. Using a 1/4 I allen wrench, remove the three allen head bolts (1 bolt on ...

4-10 12 3 4 5 678 10 9 1. Coil Retaining Screw 2. Nameplate 3. Coil Housing Assembly 4. Enclosing Tube & Bonnett Assembly 5. Kick-Off Spring 6. Plunger 7. Closing Spring 8. Diaphragm 9. O-Ring 10. Valve Body Figure 4-10. Reheat Coolant Valve Assembly (RCV) 4.16 SERVICING THE LIQUID LINE SOLENOID...