background image

i

SAFETY SUMMARY

GENERAL SAFETY NOTICES

The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this manual.

They are recommended precautions that must be understood and applied during operation and maintenance of the

equipment covered herein. The general safety notices are presented in the following three sections labeled: First Aid,

Operating Precautions and Maintenance Precautions. A listing of the specific warnings and cautions appearing

elsewhere in the manual follows the general safety notices.

FIRST AID

An injury, no matter how slight, should never go unattended. Always obtain first aid or medical attention immediately.

OPERATING PRECAUTIONS

Always wear safety glasses.
Keep hands, clothing and tools clear of the evaporator and condenser fans.
No work should be performed on the unit until all circuit breakers and start-stop switches are turned off, and power

supply is disconnected.
Always work in pairs. Never work on the equipment alone.
In case of severe vibration or unusual noise, stop the unit and investigate.

MAINTENANCE PRECAUTIONS

Beware of unannounced starting of the evaporator and condenser fans. Do not open the condenser fan grille or

evaporator access panels before turning power off, and disconnecting and securing the power plug.
Be sure power is turned off before working on motors, controllers, solenoid valves and electrical control switches. Tag

circuit breaker and power supply to prevent accidental energizing of circuit.
Do not bypass any electrical safety devices, e.g. bridging an overload, or using any sort of jumper wires. Problems with the

system should be diagnosed, and any necessary repairs performed, by qualified service personnel.
When performing any arc welding on the unit, disconnect all wire harness connectors from the modules in the control

box. Do not remove wire harness from the modules unless you are grounded to the unit frame with a static-safe wrist

strap.
In case of electrical fire, open circuit switch and extinguish with CO

2

(never use water).

Summary of Contents for Carrier TRANSICOLD 68RM35-604-20

Page 1: ...T 288 Rearmount 68RM35 604 20 R 134a NYCDOT...

Page 2: ...MANUAL OPERATION AND BUS AIR CONDITIONING UNIT Rearmount 68RM35 604 20 R 134a Carrier Transicold Division Carrier Corporation P O Box 4805 Syracuse N Y 13221 Carrier Corporation 1999 D Printed in U S...

Page 3: ...r supply is disconnected Always work in pairs Never work on the equipment alone In case of severe vibration or unusual noise stop the unit and investigate MAINTENANCE PRECAUTIONS Beware of unannounced...

Page 4: ...rosive and toxic compounds WARNING Be sure to avoid refrigerant coming in contact with the eyes Should refrigerant come in contact with the eyes wash eyes for minimum of 15 minutes with potable water...

Page 5: ...1 3 TROUBLESHOOTING 3 1 3 1 UNIT WILL NOT COOL 3 1 3 2 SYSTEM RUNS BUT HAS INSUFFICIENT COOLING 3 1 3 3 ABNORMAL PRESSURES 3 1 3 4 ABNORMAL NOISES OR VIBRATIONS 3 2 3 5 TEMPERATURE CONTROLLER MALFUNC...

Page 6: ...r 4 13 4 18 5 Removing Oil from the Compressor 4 13 5 ELECTRICAL SCHEMATIC WIRING DIAGRAM 5 1 5 1 INTRODUCTION 5 1 LIST OF ILLUSTRATIONS Figure Page 1 1 Unit Assembly Back View 1 2 1 2 Unit Assembly I...

Page 7: ...l 05G Compressor 4 12 4 12 Compressor Oil Charge Connections 4 13 5 1 Electrical Schematic Diagram Legend and Symbols 5 2 5 2 Electrical Schematic Diagram 5 3 LIST OF TABLES Table Page 1 1 Model Chart...

Page 8: ...of the bus These units interface with the bus driver switches and pump to provide a complete air conditioning system All control systems are powered by 24 vdc supplied by the bus battery and alternato...

Page 9: ...11 Discharge Line Isolation Valve 12 Receiver Sight Glass Upper 13 Moisture Liquid Indicator 14 Unloader Pressure Switch UPS3 Upper 15 Condenser Fan Switch CFS Lower 16 Evaporator Fan Housing Curbsid...

Page 10: ...CS 1 Electrical Control Panel See Figure 1 3 2 Liquid Line Solenoid Valve 3 Thermostatic Expansion Valve TXV 4 Roadside Blower Housing 5 Air Filter 6 Evaporator Coil 7 Curbside Blower Housing 1 CDR 6...

Page 11: ...14 Cool Disable Relay CDR 15 Evaporator Speed Relay ESR 16 Power Terminal Block PTB 17 Return Air Probe 18 Air Conditioning Stop Relay No 2 ACSR2 19 Heat Relay HR 20 Air Conditioning Stop Relay No 1...

Page 12: ...k 05G Compressor Electric Unloader Pressure Switches UPS1 UPS2 UPS3 See Table 1 2 for settings 1 3 ELECTRICAL SPECIFICATIONS a Evaporator Blower Motor Bearing Lubrication Factory Lubricated additional...

Page 13: ...r no 2 Circuit Breaker CB2 Manual Reset Opens at 60 amps Excessive current draw by evaporator fan motor no 1 Circuit Breaker CB3 Manual Reset Opens at 60 amps Excessive current draw by condenser fan m...

Page 14: ...h set point then the evaporator fan motors will not operate when the thermostat is calling for heat Condenser Motor Overload COL1 and COL2 Each condenser fan motor is equipped with an internal thermal...

Page 15: ...ON position EFR1 and EFR2 relays are energized When energized a set of internal EFR1 and EFR2 contacts are closed to start the evaporator fan motors Evaporator Overload Relays OR1 and OR2 Evaporator o...

Page 16: ...nt supply of liquid is available to the evaporator coil as needed and as a storage space when pumping down the system The receiver is equipped with a sight glass to observe correct charge level and a...

Page 17: ...er Drier Outlet Valve 9 Thermostatic Expansion Valve 10 Evaporator Coil 11 Suction Line 12 Subcooler 13 Liquid Suction Heat Exchanger 14 Condenser Fan Switch CFS 15 Unloader Pressure Switch UPS3 16 Ch...

Page 18: ...ts to interrupt the compressor clutch circuit when the ambient temperature falls to 45_F 7 2_C Heat is then accomplished by cycling Boost Pump Motor BPM and Reheat Coolant Valve RCV to supply engine c...

Page 19: ...above the thermostat set point the HEAT COOL switch remains in COOL and the HIGH LOW switch remains in the HIGH position The thermostat discontinues supplying the signal to semi unload the compressor...

Page 20: ...2 3 T 288 Figure 2 2 Automatic High Speed Cool Mode Operation with Reheat TDR 10 SEC...

Page 21: ...2 4 T 288 Figure 2 3 Automatic High Speed Cool Mode Operation No Reheat TDR 10 SEC...

Page 22: ...2 5 T 288 Figure 2 4 Automatic High Speed Heat Mode Operation Below 45_F Ambient TDR 10 SEC...

Page 23: ...refrigerant flow Low refrigerant charge Service valves partially closed Safety device open Liquid line solenoid valve stuck closed 3 3 3 6 3 7 3 7 and 4 12 4 9 Open 1 4 Check 3 3 ABNORMAL PRESSURES Hi...

Page 24: ...s defective Motor brushes defective Evaporator fan loose or defective Return air filter dirty Icing of coil dirty coil Fan relays EFR1 OR EFR2 defective Safety device open Check 5 1 4 16 4 16 4 16 Cle...

Page 25: ...refrigerant lines Turning the valve stem counterclockwise all the way out willbackseat the valve to open the suction or discharge line to the compressor and close off the gauge connection In normal op...

Page 26: ...h O Ring Hose Fitting with O Ring Figure 4 2 R 134a Manifold Gauge Set Connections To service the refrigerant system the manifold gauge set is connected to the compressor suction low side service valv...

Page 27: ...d always be used whenever removing contaminated refrigerant from the system If a recovery system is not available proceed as follows a Equipment Required 1 Appropriate evacuated returnable refrigerant...

Page 28: ...the system prior to leak repair 8 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 compone...

Page 29: ...ifold 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 with service valve caps...

Page 30: ...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 corre...

Page 31: ...ight as viewed Finger tighten flare nuts h Tighten filter drier flare nuts using two open end wrenches i Install vacuum pump on filter drier inlet valve Evacuate to 500 microns and disconnect vacuum p...

Page 32: ...s No Continuity Switch Opens Continuity Switch Closes High Press ure HPS 300 10 psig 200 10 psig Low Press ure LPS 6 3 psig 25 3 psig Condenser Fan Speed CFS 250 10 psig 190 15 psig Unloader Pressure...

Page 33: ...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 on the compressor suction service valve 5 Set tempe...

Page 34: ...unger or deformed valve body assembly Failure to close may be caused by the following a Defective plunger or deformed valve body assembly b Foreign material in the valve It is not necessary to drain t...

Page 35: ...Clip Bolt 5 Venturi 6 Evaporator Motor 7 Hub Set Screw 7 Figure 4 10 Evaporator Fan Blower Assembly 4 16 1 Routine Examination and Cleaning a At regular maintenance periods remove brush covers and cl...

Page 36: ...second filter past the holding channel to the center position and remove e Repeat the above step with the third filter f Reverse the procedure for installing the new filters 4 18 COMPRESSOR 4 18 1 Rep...

Page 37: ...4 18 2 Checking the Compressor Oil Level NOTE It may be necessary to preheat the coach and or operate the system in the Reheat Mode to keep the compressor fully loaded throughout this procedure a Ope...

Page 38: ...n 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 ope...

Page 39: ...is no pressure at the oil drain plug d 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 c...

Page 40: ...5 0 26 0 26 70 21 71 1 490 2 5 00 4 90 4 20 4 6 31 7 0 32 0 32 75 24 78 7 542 6 5 53 5 43 2 19 5 6 36 6 0 39 0 39 80 27 86 7 597 8 6 10 5 98 0 18 6 5 44 8 0 46 0 45 85 29 95 3 657 1 6 70 6 57 2 17 7...

Page 41: ...5 1 INTRODUCTION This section contains Electrical Schematic Wiring Diagrams covering the Models listed in Table 1 1 Before performing operation and maintenance on the equipment ensure that precaution...

Page 42: ...HIGH PRESSURE SWITCH HR HEAT RELAY HR2 HEAT RELAY 2 LATH LOW AMBIENT THERMOSTAT LPS LOW PRESSURE SWITCH LSV LIQUID SOLENOID VALVE OR1 EVAPORATOR OVERLOAD RELAY 1 OR2 EVAPORATOR OVERLOAD RELAY 2 PTB P...

Page 43: ...5 3 T 288 Figure 5 2 Electrical Schematic Diagam Based on Drawing 68RM35 1038 12 TDR 10 SEC...

Page 44: ...1 4 7 4 8 Condenser Motor Overload 1 7 Condenser Speed Relay 1 4 1 7 1 8 Cool Disable Relay 1 4 1 8 Coolant Valve 3 2 D Description 1 1 3 1 Discharge Line Check Valve 1 2 Discharge Line Isolation Valv...

Page 45: ...Glass 1 2 Refrigerant Charge 1 5 Reheat Coolant Valve 1 5 2 1 3 2 4 9 Relay Board 1 1 1 4 1 8 Return Air Probe 1 4 S Safety Devices 1 5 1 6 3 1 3 2 Schematic Wiring Diagrams 5 1 Service Valves 3 1 Sub...

Reviews: