Carrier GR-45 Operation And Service
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Carrier GR-45 Operation And Service

Carrier GR-45 Operation And Service

Bus air conditioning unit
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Bus Air
Conditioning
Equipment
Models
GR- -45
GR- -60
(N. A. O.)
T- -295
AC Pressure Sensor

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Summary of Contents for Carrier GR-45

  • Page 1 Bus Air Conditioning Equipment Models GR- -45 GR- -60 (N. A. O.) T- -295 AC Pressure Sensor...
  • Page 2 UNIT Models GR- -45 GR- -60 (N. A. O.) Carrier Refrigeration Operations Carrier Transicold Division, Carrier Corporation, P .O. Box 4805, Syracuse, N.Y. 13221 U. S. A. Carrier Corporation 2000 D Printed in U. S. A. 0300 AC Pressure Sensor...

  • Page 3: Safety Summary

    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. A listing of the specific warnings and cautions appearing elsewhere in the manual follows the general safety notices.

  • Page 4: Table Of Contents

    TABLE OF CONTENTS PARAGRAPH NUMBER Page SAFETY SUMMARY ..............Safety-1 DESCRIPTION .
  • Page 5 TABLE OF CONTENTS (Continued) PARAGRAPH NUMBER Page 2.3.11 Alarm Description ............2.3.12 Hour Meters .
  • Page 6 TABLE OF CONTENTS (Continued) PARAGRAPH NUMBER Page ADDING REFRIGERANT TO SYSTEM ......... . . 4.8.1 Checking Refrigerant Charge .
  • Page 7 LIST OF ILLUSTRATIONS FIGURE NUMBER Page Figure 1-1. A/C Component Identification ..........Figure 1-2.
  • Page 8 LIST OF TABLES TABLE NUMBER Page Table 2-1. Evaporator Fan Speed Relay Operation ..........Table 2-2.

  • Page 9: Description

    Instructions and Electrical Data for the Model GR Air components furnished by the bus manufacturer. Conditioning and Heating equipment furnished by Carrier Transicold Division as shown in Table 1-1. Operation of the units is controlled automatically by a Model GR systems consists of an Apex Unit, containing...

  • Page 10: General Description

    1.2 GENERAL DESCRIPTION section, evaporator section, Micromax electronics, and the Fresh Air System. All components are accessible by 1.2.1 Apex Unit lifting the top cover. Descriptions of the systems are The apex unit (see Figure 1-2) includes the condensing provided in the following sub paragraphs. Top Cover Hinge Gas Spring (2)

  • Page 11: Figure 1-3. Condensing Section Components

    The receiver collects and stores liquid refrigerant. The sensor measures ambient temperature and sends an receiver is fitted with upper and lower liquid level sight electrical signal to the controller. glasses to enable determining refrigerant liquid level. The receiver is also fitted with a fusible plug which The discharge check valve is a spring loaded, normally protects the system from unsafe high pressure closed valve that opens with the flow of refrigerant from...

  • Page 12: System Operating Controls And Components

    (charging) ports The system is operated by a Carrier Transicold and electric solenoid unloaders. Micromax microprocessor controller which consist of a logic board (Figure 1-10), relay board (Figure 1-8 or The compressor raises the pressure and temperature of Figure 1-9), and manual operator switches.

  • Page 13: Refrigeration System Component Specifications

    MOP Setting (Nonadjustable): 55 ±4 psig (3.74 by unsafe operating conditions with safety devices. ±2.27 bar) Safety devices with Carrier Transicold supplied equipment include high pressure switch (HPS), low d. High Pressure Switch (HPS): pressure switch (LPS), circuit breakers and fuses.

  • Page 14: Air Flow

    Low Pressure Switch (LPS) The compressor raises the pressure and the temperature of the refrigerant and forces it into the condenser tubes. The low pressure switch is installed in the compressor The condenser fan circulates surrounding air (which is and opens on a pressure drop to shut down the system at a temperature lower than the refrigerant) over the when a low pressure condition occurs.

  • Page 15: Figure 1-6. Refrigerant Flow Diagram

    RECEIVER DISCHARGE LIQUID MAIN ENGINE SUCTION RADIATOR VIEW A-A COMPRESSOR Condenser Fan Assembly Pressure Transducer, High Side Evaporator Fan Assembly Service Valve With Port Expansion Valve Liquid Line Solenoid Valve Expansion Valve Equalizer Line Filter Drier Liquid Line Service Port, High Side Precharge Valve Discharge Check Valve Expansion Valve Bulb...

  • Page 16: Heating Cycle

    Heating circuit (Figure 1-7) components furnished by Carrier Transicold include the integral evaporator coil an auxiliary boost water pump. When the heat valve heater cores and a solenoid operated heat valve.

  • Page 17: Permanent Magnet Motors With 2 Speed Switching From Series To Parallel Connection (Option 1)

    1.10 RELAY BOARD 1.10.1 Permanent Magnet Motors with 2 speed switching from series to parallel connection (Option 1) CB 13 CB 11 CB 1 CB 5 CB 7 CB 12 CB 2 CB 6 CB 8 K12 D85 CB 3 CB 9 D2 D6 D26 D30...
  • Page 18 b. Thermal Circuit Breakers JP6 Unloaders 1 & 2. CB 1 Evaporator Fan #1. 15 Amp. d. LEDS CB 2 Evaporator Fan #2. 15 Amp. D 2 Relay K1 output active (evaporator fans 1,2,3 & CB 3 Evaporator Fan #3. 15 Amp.

  • Page 19: Electronically Communtated Dc Motors With 2- -Speed Evaporator Input Signal (Option 2)

    1.10.2 Electronically Communtated DC Motors with 2- -speed Evaporator Input Signal (Option 2) CB 13 CB 11 CB 1 CB 5 CB 7 CB 12 CB 8 CB 2 CB 6 CB 3 CB 9 D2 D6 CB 10 CB 4 EF HIGH SIGNAL CF HIGH SIGNAL Figure 1-9 Relay Board (Option 2)

  • Page 20: Logic Board

    1.11 LOGIC BOARD J1 Logic board power in. J7 Diagnostics interface (RS232, DB9). J2 Display interface. D2 Blinks once per second in normal operation. J3 Manual control inputs. On steady to indicate alarms detected. J4 Interlock Inputs D3 Off In normal operation, blinks out alarm (WTS, low side pressure switch etc.) codes (2 digits each) when alarms detected.

  • Page 21: Control Panel (Diagnostic Module)

    1.12 CONTROL PANEL (Diagnostic Module) Display HEAT (Only) Button DOWN Button -- decrease selection FAN SPEED Button UP Button -- increase selection FRESH AIR Button VENT (Only) Button TEMPERATURE ( Inside / Outside) AUTO Button (Automatic Control) Button COOLING (Only) Button ON/OFF Button Figure 1-11.

  • Page 22: Operation

    SECTION 2 OPERATION 2.1 STARTING, STOPPING AND OPERATING 4 If low or high speed evaporator fan speed is desired, INSTRUCTIONS press the FAN SPEED button to illuminate the indi- cator light and bring speed to the desired level. 2.1.1 Power to Logic Board 5 To open or close the fresh air damper, press the FRESH AIR button to illuminate the indicator light Before starting, electrical power must be available from...

  • Page 23: Figure 2-1 Capacity Control Diagram

    HEAT MODE AUTO MODE REHEAT AUTO MODE CYCLE COOL COOL 2°F HIGH SPEED HIGH SPEED 3°F 3°F LOADED LOADED COOL COOL 1°F HIGH SPEED HIGH SPEED 2°F 2°F 4 CYLINDERS 4 CYLINDERS COOL COOL SETPOINT LOW SPEED LOW SPEED 1°F 1°F 2 CYLINDERS 2 CYLINDERS...

  • Page 24: Modes Of Operation

    2.3 MODES OF OPERATION 2.3.4 Boost Pump When the unit is in heat the boost pump relay is The system is operated by a Carrier Transicold energized, providing 24 VDC to activate the boost Micromax microprocessor controller which consists of pump.

  • Page 25: Evaporator Fan Speed Selection

    The unloaders are used to control suction pressure and activated if a high pressure alarm has been activated and thereby prevent coil frosting: operation has not been locked out (refer to Table 3-3). 1 Compressor Unloader UV1 Relay. When the suction 2.3.10 Compressor Clutch Control pressure decreases below 26 psig (1.77 bar), unload- A belt driven electric clutch is employed to transmit...

  • Page 26: Table 2-2. Controller Test List

    After two seconds, the display will show any control configuration is changed. the data for the current parameter. When the last Carrier can not be responsible for failures or parameter is reached, the list will wrap back to P1. damage...

  • Page 27: Table 2-3. Parameter Codes

    Table 2-3. Parameter Codes CODE CODE NAME DESCRIPTION Return Air This value is the temperature measured by the return air sensor. If the sensor is Temperature shorted it will display CL. If it is open circuited it will display OP. Coil Temperature This value is the coil temperature measured by the evaporator temperature sen- sor.
  • Page 28 Table 2-3. Parameter Codes - - Continued Code Code Name Description Maximum Setpoint This is the maximum value that the operator will be allowed to set the setpoint temperature. The value can be modified in degrees with the up and down keys to a value between 60F and 80F.

  • Page 29: Troubleshooting

    SECTION 3 TROUBLESHOOTING CAUTION Do not under any circumstances attempt to service the microprocessor. should a problem develop with the microprocessor, replace it. 3.1 SELF DIAGNOSTICS error codes can be read by counting the number of times that the Logic Board STATUS and CODE LED’s (see A self test is performed by the Micromax Logic Board Figure 1-10) flash simultaneously.

  • Page 30: Table 3-2 Alarm Codes

    Table 3-2 Alarm Codes ALARM TITLE CAUSE REMEDY CONTROLLER RESPONSE Coil Freeze Coil temperature is Check causes of coil An alarm will be gener- less than 32F and the freezing. (Refer to ated and the system will compressor is operat- section 3.3.6) shutdown.
  • Page 31 Table 3-2 Alarm Codes - - Continued ALARM TITLE CAUSE REMEDY CONTROLLER RESPONSE Breaker Trip Alarm A breaker on the relay Check breakers for Alarm will be generated. board has tripped or a tripped device. Repair fan relay has failed. short and reset break- Evaporator Fan Overload Evaporator fan over- Ensure connector is...

  • Page 32: Table 3-3 General System Troubleshooting Procedures

    Table 3-3 General System Troubleshooting Procedures INDICATION/ REFERENCE POSSIBLE CAUSES TROUBLE SECTION 3.3.1 System Will Not Cool Compressor will not run Active system alarm V-Belt loose or defective Check Clutch coil defective Check/Replace Clutch malfunction Check/Replace Compressor malfunction See Table 1-2. Electrical malfunction Coach power source defective Check/Repair...

  • Page 33: Control System Malfunction

    Table 3-3 General System Troubleshooting Procedures - - Continued INDICATION/ REFERENCE POSSIBLE CAUSES TROUBLE SECTION 3.3.4 Abnormal Noise Or Vibrations - - Continued Condenser or evaporator fans Loose mounting hardware Check/Tighten Defective bearings Replace Blade interference Check Blade missing or broken Check/Replace 3.3.5 Control System Malfunction Will not control...

  • Page 34: Figure 4-1. Opening Top Cover

    SECTION 4 SERVICE WARNING BE SURE TO OBSERVE WARNINGS LISTED IN THE SAFETY SUMMARY IN THE FRONT OF THIS MANUAL BEFORE PERFORMING MAINTENANCE ON THE HVAC SYSTEM NOTE Following completion of all maintenance or service activities, the alarm queue should be cleared of any origi- nal alarms and any alarms generated during service.

  • Page 35: Figure 4-2.Suction Or Discharge Service Valve

    e. Frontseat (clockwise) both manifold gauge hand TO DISCHARGE OR VALVE CAP valves. FROM SUCTION LINE f. Turn the service valve connected to the discharge gauge port toward frontseat (clockwise) approxi- mately 1/4 to 1/2 turn. g. Slowly turn the manifold discharge hand valve to- ward backseat (counterclockwise) approximately one turn.

  • Page 36: Figure 4-4. Low Side Pump Down Connections

    f. Check refrigerant level. Refer to paragraph 4.8.1. It may be necessary to clear any alarms that have been generated. 1. Filter-Drier Inlet 5. Vacuum Pump Service Valve 6. Refrigerant Cylinder 2. Thermostatic 7. Reclaimer 1. Discharge Service 4. Vacuum Pump Expansion Valve 8.

  • Page 37: Figure 4-6. System Charge Removal Connections

    c. Add sufficient nitrogen to raise system pressure to 150 to 200 psig (10.21 to 13.61 bar). d. Check for leaks. The recommended procedure for finding leaks in a system is with an electronic leak de- tector. Testing joints with soapsuds is satisfactory only for locating large leaks.

  • Page 38: Adding Refrigerant To System

    g. Remove refrigerant using a refrigerant recovery sys- 4.8.3 Adding Partial Charge tem. a. Install manifold gauge set at the compressor suction service valve and service port above the discharge h. Start vacuum pump and open all valves. Dehydrate line check valve. See figure Figure 4-6. unit to 500 microns Hg vacuum.

  • Page 39: Filter-Drier

    4.11.2 To Replace Filter- -Drier a. Perform a low side pump down. Refer to paragraph 4.5.1. b. Turn the driver’s A/C switch to “OFF” position. c. Frontseat the filter- -drier outlet service valve and place a new filter-drier near the unit for immediate installation.

  • Page 40: Evaporator Coil Replacement

    4.13 EVAPORATOR COIL REPLACEMENT b. Place main battery disconnect switch in OFF position and lock. a. If refrigerant remains in the system, perform a low c. Disconnect wire leads to coil. side pump down to remove refrigerant from the evap- orator coils.

  • Page 41: Coil Replacement

    4.15 SERVICING THE LIQUID LINE SOLENOID VALVE The Liquid line solenoid valve (Figure 4-10) is very similar to the heat valve. It 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 refrigeration system, or improper voltage to the coil.

  • Page 42: Inspection And Cleaning

    4.16.2 Inspection And Cleaning d. To reassemble, reverse procedure. a. At regular maintenance periods, remove brush cov- 4.18 REPLACING RETURN AIR FILTERS ers, examine and clean motor interior. The return air filters are located behind the return air b. Place main battery disconnect switch in OFF position grill, inside the vehicle.

  • Page 43: Superheat Measurement

    e. Remove capscrews and lift off power head and cage c. Loosen one TXV bulb clamp and make sure area un- assemblies and gaskets. der clamp is clean. d. Place temperature thermocouple in contact with the f. Check, clean and remove any foreign material from suction tube and parallel to the TXV bulb, and then the valve body, valve seat and mating surfaces.

  • Page 44: Transferring Compressor Clutch

    NOTES ate compressor to 500 microns. Front seat both man- ifold valves to isolate the pump. Service replacement compressors are sold without service valves. Valve pads are l. Start unit and check refrigerant level (refer to para- graph 4.8.1). installed in their place. The optional unloaders are not supplied, as the cylinder m.Check compressor oil level (refer to paragraph heads are shipped with plugs.

  • Page 45: Compressor Oil Level

    0.030 inch (0.41 to 0.76 mm). If required, remove the 3. Evacuate compressor to 500 microns. Backseat eight armature spacer nuts and spacer. Add or remove compressor suction and discharge valves, start sys- shims to adjust gap. Reinstall spacer nuts and tighten tem and recheck oil level.

  • Page 46: Temperature Sensor Checkout

    connector. Pressure should decrease 3 to 5 psi (0.2 to c. At least one sensor lead must be disconnected from 0.4 bar) when the unloader is unplugged and increase the controller before any reading can be taken. Not the same amount as the plug is reconnected. repeat doing so will result in a false reading.

  • Page 47: Table 4-2. Pressuretransducer Voltage

    Table 4-3. Logic Board Configuration Table 4-2. PressureTransducer Voltage “/hg Voltage Psig Voltage Psig Voltage Jumper Description 20” 0.369 1.446 2.573 High Reheat - - Selects fan speed 10” 0.417 1.495 2.622 High Vent - - Selects fan speed 1.544 2.671 Psig Voltage...
  • Page 48 Table 4-4. R-134a Temperature - Pressure Chart Temperature Vacuum Temperature Pressure     cm/hg kg/cm@ @ @ @ kg/cm@ @ @ @ “/hg psig - -40 - -40 14.6 49.4 37.08 0.49 - -2 24.5 168.9 1.72 1.69 - -1 26.1 180.0...

  • Page 49: Electrical

    SECTION 5 ELECTRICAL 5- -1 INTRODUCTION This section includes electrical wiring schematics. The schematic shown in this section provides information for all unit models and optional configurations. For model GR45 units, which are fitted with four evaporator and condenser fans, the components used to control the fifth and sixth fans are not energized. For applications with OEM supplied operating switches, the switches are wired to Logic Board connector J3 as shown.

  • Page 50: Figure 5- -1. Electrical Wiring Schematic Diagram - Legend

    LEGEND CONNECTOR LEGEND SYMBOLS SYMBOL DESCRIPTION SYMBOL DESCRIPTION AMBIENT TEMPERATURE SENSOR CONNECTOR TERMINAL LOGIC POWER BOOST PUMP SIGNAL ON/TEST CIRCUIT BREAKER, EF1 INPUT GROUND CIRCUIT BREAKER, EF2 RELAY BOARD INTERFACE CIRCUIT BREAKER, EF3 SENSOR CIRCUIT BREAKER, EF4 FACTORY WIRING DIAGNOSTIC LINK CIRCUIT BREAKER, EF5 MOTOR OVERLOAD CIRCUIT BREAKER, EF6...

  • Page 51: Figure 5- -2. Wiring Schematic, Permanent Magnet Motors - Interconnection

    Figure 5- -2. Wiring Schematic, Permanent Magnet Motors - Interconnection T--295...

  • Page 52: Figure 5- -3. Wiring Schematic, Permanent Magnet Motors - Relays To External Components

    F(150A) +24VDC POWER CABLE 1- -120 (NOVA) CB10 CB11 CB12 1- -121 (NOVA) POWER CABLE (- -) MOTOR CONNECTION MARKING CB13 W_FAV W_FAV TYPICAL ALL MOTORS SPARE CIRCUIT BREAKER W_COMP W_COMP CONNECTION MARKING TYPICAL ALL BREAKERS W_COMP W_COMP ALL BREAKERS 15 AMP W_COMP W_COMP RELAY CONNECTION...

  • Page 53: Figure 5- -4. Wiring Schematic, Electronically Communtated Motors - Interconnection

    Figure 5- -4. Wiring Schematic, Electronically Communtated Motors - Interconnection T--295...

  • Page 54: Figure 5- -5. Wiring Schematic, Electronically Communtated Motors - Relays To External Components

    TO J4- -5 F (125A) +24VDC POWER SEE PRECEEDING DIAGRAM CABLE CB10 CB11 CB12 EF HIGH MOTOR CONNECTION MARKING TYPICAL ALL MOTORS CB13 W_FAV W_FAV SPARE CIRCUIT BREAKER CONNECTION MARKING TYPICAL ALL BREAKERS W_COMP W_COMP ALL BREAKERS 15 AMP W_COMP W_COMP RELAY CONNECTION MARKING...

  • Page 55: Index

    INDEX Air Filters, 4-9 Filter- -Drier, 4-6 Alarm, 2-4, 3-1 Fresh Air System, 1-4, 2-3 Alarm Clear, 3-1 Fuse, 1-6 Alarm Codes, 3-1 Alarm Queue, 3-1 Ambient Lockout, 1-6 Heat Valve, 4-7 Apex Unit, 1-2 Heating Cycle, 1-8 Heating Mode, 2-3 High Pressure Switch, 1-5, 4-5 Boost Pump, 2-3 Hour Meter, 2-4...
  • Page 56 INDEX - - Continued Pre- -Trip Inspection, 2-1 Temperature Control, 2-3 Pressure Transducer, 1-5, 4-13 Temperature Pressure Chart, 4-15 Pump Down, 4-2, 4-3 Temperature Sensor, 1-5, 4-13 Thermostatic Expansion Valve, 1-5, 4-9 Top Cover, 4-1 TROUBLESHOOTING, 3-1 Refrigerant Charge, 1-5, 4-2, 4-4, 4-5 Refrigerant Removal, 4-3, 4-4 Refrigeration Cycle, 1-6 Relay Board, 1-9...

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