Carrier 68G5-105 Series Operation & Service Manual
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Carrier 68G5-105 Series Operation & Service Manual

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Carrier
Transicold
Transport
Air Conditioning
68G5-105 SERIES
MCI J4500 COACH
T-312 Rev-
Operation
& Service

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  • Page 1 Carrier Transicold Transport Air Conditioning 68G5-105 SERIES MCI J4500 COACH Operation & Service T-312 Rev-...

  • Page 2: Service Manual

    MCI J4500 Model Coach Carrier Transport Refrigeration and Air Conditioning, A member of the United Technologies Corporation family. Stock symbol UTX. Carrier Transicold, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221 U. S. A. 2003 CarrierCorporation D Printed in U. S. A. 0903...

  • 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. The general safety notices are presented in the following three sections labeled: First Aid, Operating Precautions and Maintenance Precautions.
  • Page 4 SPECIFIC WARNINGS AND CAUTIONS WARNING BE SURE TO OBSERVE WARNINGS LISTED IN THE SAFETY SUMMARY IN THE FRONT OF THIS MANUAL BEFORE PERFORMING MAINTENANCE ON THE HVAC SYSTEM WARNING DO NOT USE A NITROGEN CYLINDER WITHOUT A PRESSURE REGULATOR WARNING DO NOT USE OXYGEN IN OR NEAR A REFRIGERATION SYSTEM AS AN EXPLOSION MAY OCCUR.

  • Page 5: Table Of Contents

    ........1.2.6 Other Carrier Supplied Items .
  • Page 6 TABLE OF CONTENTS - - Continued Section Page 2.3.15 Alarm Description ............2.3.16 Hour Meters .
  • Page 7 TABLE OF CONTENTS - - Continued Section Page 4.12 MODEL 05G COMPRESSOR MAINTENANCE ........4.12.1 Removing the Compressor .
  • Page 8 ............1-3. Safety Devices (Within Carrier Supplied Equipment) .

  • Page 9: Description

    Coach Air Conditioning and Heating equipment The 68G5 air conditioning and heating equipment furnished by Carrier Transicold Division for the MCI interfaces with electrical cabling, a parcel rack J-Series Intercity coach. Table 1-1 provides a model evaporator thermostat kit, refrigerant piping, engine number chart.

  • Page 10: General Description

    1.2 GENERAL DESCRIPTION The condenser is also fitted with a fusible plug which protects the system from unsafe high temperatures. 1.2.1 Condenser Assembly The control box includes condenser fan relays no. 1 and The condenser assembly (See Figure 1-2) includes a no.
  • Page 11 DRIVE END VIEW PUMP END VIEW CURBSIDE VIEW TOP VIEW Suction Pressure Transducer Bracket, Belt Guard Weatherpack Clutch Coil Connector 17 16 Electric Solenoid Unloader Discharge Valve Connection, Size 16 ORS Discharge Service Valve Discharge Valve Charging Port O–Ring Oil Drain Plug Solenoid Unloader Electric Connectors High Pressure Switch Discharge Pressure Transducer...

  • Page 12: Compressor Assembly

    1.2.2 Compressor Assembly motor assemblies, an air filter, and two condensate drain connections. The evaporator heat valve (EHV) for The compressor assembly (See Figure 1-3.) includes the driver evaporator is installed in the piping outside the the refrigerant compressor, clutch assembly, suction evaporator assembly.
  • Page 13 Suction Outlet Connection Fan and Motor Liquid Inlet Connection Motor Mount Bracket Side Access Panel Condensate Drain Connection Top Access Panel Relay Thermal Expansion Valve Thermostat (Not supplied by Carrier) Evaporator Coil Assembly Figure 1-5. Parcel Rack Evaporator Assembly T-312...
  • Page 14 Thermal Expansion Valve Refrigerant Liquid Inlet Connection, 3/8“ ORS Evaporator/Heater Coil Assembly Heater Coil Inlet Connection, 7/8 OD Evaporator Heat Valve (EHV) Blower Housing, Right Blower Wheel, Right Nameplate Evaporator Fan Relay, High Speed (EFRH) Evaporator Fan Relay, Low Speed (EFRL) Elastomeric Motor Mounts 2-Speed Motor Blower Wheel, Left...

  • Page 15: Main Control Box

    1.2.4 Main Control Box the air conditioning and heating system to maintain temperatures inside the coach. The microprocessor The main control box (See Figure 1-7) includes a main section has a built in memory facility for checking proper controller (microprocessor module), expansion output operation;...

  • Page 16: System Operating Controls (Upper Left Hand Switch Panel)

    The compressor is activate the system to provide cooling for the driver in fitted with cylinder unloaders to match compressor the event that cooling is not called for by the Carrier capacity to the bus requirements. Once the interior Transicold microprocessor.

  • Page 17: Other Carrier Supplied Items

    High Speed: 56 1.2.6 Other Carrier Supplied Items Low Speed: 28 Operating Speed: Other Carrier supplied items include curbside and High Speed: 1550 rpm roadside return air temperature sensors, two coolant Low Speed: 1200 rpm control valves and a check valve. The temperature...

  • Page 18: Safety Devices

    Opening HPS caused by unsafe operating conditions with safety contacts de-energizes, through the main controller, the devices. Safety devices that are connected to Carrier A/C compressor clutch and condenser fan relays Transicold supplied equipment include a high pressure shutting down the system.

  • Page 19: Heating (Engine Coolant) Flow Cycle

    1.7 HEATING (ENGINE COOLANT) FLOW CYCLE main controller automatically controls the EHV valves during heating and reheat cycles to maintain required Heating circuit components furnished by Carrier temperatures inside the coach. Engine coolant (glycol Transicold include heater cores and evaporator heat...

  • Page 20: Air Conditioning Refrigerant Cycle

    1.8 AIR CONDITIONING REFRIGERANT CYCLE parcel rack evaporator solenoid valve (if this option is active) the parcel rack thermal expansion valve and When air conditioning (cooling) is selected by the main through the driver solenoid valve (if this option is active) controller, the unit operates as a vapor compression and to the driver thermal expansion valve.

  • Page 21: Air Conditioning Refrigerant Flow Diagram

    DRIVER SOLENOID VALVE Discharge TXV BULB Liquid Suction DRIVER EVAPORATOR SERVICE PORT ASSEMBLY TXV BULB MAIN EVAPORATOR ASSEMBLY SERVICE PORT CONDENSER PARCEL EVAPORATOR ASSEMBLY ASSEMBLY PARCEL RACK LIQUID LINE MAIN LIQUID LINE SOLENOID VALVE SOLENOID VALVE FILTER DRIER SERVICE CONDENSER PORT SIGHT- - GLASS...

  • Page 22: Electronic Automatic Control Data Flow

    1.9 ELECTRONIC AUTOMATIC CONTROL DATA temperature conditions inside the coach. The driver FLOW display provides a communication link between the main controller and the rest of the system. The following The system is supplied with 12 and 24 vdc power from block diagram (Figure 1-13) indicates data flow through the coach power supply.

  • Page 23: Operation

    6. Vent (Ventilation Mode Selection) -- If the VENT but- ton is pressed, the VENT LED is illuminated, only the c. The Driver Display Panel controls the Carrier Trans- system fans will operate. The AUTO, COOL, and icold microprocessor controller which in turn controls HEAT LED’s will not be illuminated.

  • Page 24: Hvac Power To Controller

    inside or outside temperature. The inside tempera- ture is obtained by averaging the curb and road side return air sensors (located in the return air ducts). If one sensor is not functioning the display will read only the functioning sensor, if both are not function- ing, the display will show ’--40’.

  • Page 25: Activating Defrost

    5. To open or close the fresh air damper, press the 2.1.8 Stopping FRESH AIR button. With the system operating, pressing the ON/OFF key will stop the HVAC system operation and the display will 6. To read interior or exterior temperature, press the be blank.

  • Page 26: Main Controller Automatic Control Sequence

    closing the heating valve. The compressor clutch and condenser fan motors are energized as appropriate. EVAPORATOR RETURN AIR TEMP Reheat allows for both net cooling and net heating by ABOVE SET POINT varying the time that the heat valve is open. The time is automatically calculated by the controller and is based COOLING MODE HIGH SPEED MAIN EVAP FAN...

  • Page 27: Bypass Heat Valve Control

    2.3.2 Bypass Heat Valve Control cylinders); this output will remain energized until the pressure increases to above 32 psig (2.18 BAR). The normally open Bypass Heat Valve is closed on 2. Compressor Unloader Bank 2 Solenoid (UV2). system start--up. During re--heat, the bypass heat valve When the suction pressure decreases below 21 psig remains closed when the heat valves are open, and (1.43 BAR), the second unloader solenoid is ener-...

  • Page 28: Staging

    2.3.9 Staging a. Display Override The RAM air can be automatically controlled or set to When the system is started, the fans are staged on to open or closed by the display. reduce the total starting current. There is no staging required for the driver evaporator fan motors, as they start immediately.

  • 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. NOTE To access LED display on the microprocessor, remove cover from main control box located in rear of electrical compartment. Table 3-1.
  • Page 30 Table 3-3. Driver Display Panel Alarm Message Definition - Continued ALARM TITLE CAUSE REMEDY MICROPROCESSOR RESPONSE Ambient Sensor is unplugged, Ensure sensor is Ignores ambient temperature and Probe Failure wiring defective or plugged in. Check does not lock out the compressor ambient temperature sensor resistance or and does not open driver RAM air in...
  • Page 31 Table 3-3. Driver Display Panel Alarm Message Definition - Continued ALARM TITLE CAUSE REMEDY MICROPROCESSOR RESPONSE Condenser Condenser fan over- Refer to section 3.3.3 If after energizing the second con- Fan Overload loads and/or 3.3.4 denser fan, the second condenser fan (continued) overload does not open, the micro- processor will keep the first over-...
  • Page 32 Table 3-3. Driver Display Panel Alarm Message Definition - Continued ALARM TITLE CAUSE REMEDY MICROPROCESSOR RESPONSE Low Pressure Low suction pressure. Check cause of low If alarm has been activated three Shutdown suction pressure. (Re- times in 30-minutes, the clutch will fer to section 3.3.3.) be de-energized until the alarm is de-activated.

  • Page 33: System Will Not Cool

    Table 3-5. General System Troubleshooting Procedures INDICATION/ REFERENCE POSSIBLE CAUSES TROUBLE SECTION 3.3.1 System Will Not Cool Compressor will not run V-Belt loose or defective Check Clutch coil defective Check/Replace Clutch malfunction Check/Replace Compressor malfunction See Note. Electrical malfunction Coach power source defective Check/Repair Circuit Breaker/safety device open Check/Reset...

  • Page 34: Control System Malfunction

    Table 3-5. General System Troubleshooting Procedures - Continued INDICATION/ REFERENCE POSSIBLE CAUSES TROUBLE SECTION 3.3.5 Control System Malfunction Will not control Sensor or transducer defective 4.13, 4.15 or 4.14 Relay(s) defective Check Microprocessor malfunction Check 3.3.6 No Evapotator Air Flow Or Restricted Air Flow Air flow through coil blocked Coil frosted over Defrost coil...

  • Page 35: Service

    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 original alarms and any alarms generated during service.

  • Page 36: Installing Manifold Gauges

    NOTE this manual. The manifold gauge/hose set is available To avoid damage to the earth’s ozone layer, from Carrier Transicold. (CTD P/N 07-00294-00, which use a refrigerant recovery system whenever includes items 1 through 6, see Figure 4-2.) To perform removing refrigerant.

  • Page 37: Refrigerant Removal From An Inoperative Compressor

    d. Frontseat the liquid line (King) valve by turning e. Once vacuum is maintained, recharge low side with clockwise. Start system and run in cooling. Stop the R-134a to 20 to 30 PSIG by admitting vapor from the unit when the suction pressure reaches 1 psig (0.07 refrigerant cylinder.

  • Page 38: Refrigerant Leak Check

    4.5 REFRIGERANT LEAK CHECK a. Evacuate and dehydrate only after pressure leak test. (Refer to paragraph 4.5) A refrigerant leak check should always be performed b. Essential tools to properly evacuate and dehydrate after the system has been opened to replace or repair a component.

  • Page 39: Refrigerant Service Connections

    1. Reclaimer 2. Manifold Guage Set 3. Thermistor Vacuum Guage 4. Vacuum Pump 5. Refrigerant Cylinder 6. Evaporator Service Port 7. Liquid Line (King) Valve and Service Port 8. Discharge Service Port Discharge Liquid DRIVER SOLENOID Suction VALVE TXV BULB DRIVER EVAPORATOR SERVICE PORT ASSEMBLY...

  • Page 40: Adding Refrigerant To System

    4.7 ADDING REFRIGERANT TO SYSTEM 1. If the actual discharge pressure is higher than the discharge pressure range, the system may be over 4.7.1 Checking Refrigerant Charge charged. a. Connect an accurate high pressure gauge to the 2. If the actual discharge pressure is lower than the discharge service port at the compressor.

  • Page 41: Checking And Replacing High Pressure Cutout Switch

    e. If gauge reading is 3 psig (.2 BAR) or higher than the f. Close cylinder valve and release pressure through calculated P/T pressure in step d, noncondensibles the bleed-off valve. As pressure drops to cut-in point, are present. the switch contacts should close, indicating continuity on the ohmmeter.

  • Page 42: To Check/Measure Superheat

    c. Loosen retaining straps holding bulb to suction line d. Place temperature thermocouple in contact with the and detach bulb from the suction line. suction tube and parallel to the TXV bulb, and then secure loosened clamp making sure both bulbs are d.

  • Page 43: Re--Installing The Compressor

    4.12.2 Re- -installing the Compressor d. Re--install and tension the compressor drive belt. e. Unlock and turn main battery disconnect switch to ON NOTES position.. 1. The service replacement f. Attach two lines (with hand valves near vacuum pump) to the suction and discharge service valves. compressors are sold without shutoff valves.

  • Page 44: Compressor Oil Level

    Remove the crankcase oil fill plug on the side of the should be warm to the touch. crankcase. g. Replace the crankcase oil fill plug with a Carrier a. Start the unit and allow the system to stabilize. Service Parts no. OTBO889 fitting. This fitting has a b.

  • Page 45: Temperature Sensor Checkout

    b. Close (frontseat) suction service valve and pump unit NOTE down to 3 to 5 psig (21 to 34 kPa). Reclaim remaining This system is equipped with three refrigerant. temperature sensors, two located in the return air ducts inside the coach, the third NOTE sensor is located in the condenser section.

  • Page 46: Replacing Sensors And Transducers

    b. Use a digital volt-ohmmeter to measure voltage d. Remove blower transitions ducts. across the transducer and compare to values in e. Remove the four bolts securing the evaporator motor Table 4-5. A reading within two percent of the values mounting plate, motor and blower housing assembly in the table would be considered good.

  • Page 47: Servicing The Main Evaporator And Heater Coil

    4.20 SERVICING THE MAIN EVAPORATOR AND j. Remove condenser module by sliding out on HEATER COIL mounting rails. a. Drain engine coolant from the heater coil. 4.22 SERVICING THE CONDENSER COIL b. Pump down low side of the HVAC system. (Refer to a.

  • Page 48: Servicing The Driver Evaporator

    b. Remove the power wire from the power stud and the 4.25.4 Removal of Evaporator/Heater Coil connector from the box. Assembly a. Clamp off silicon hose close to the input and output c. Remove the 1/4-inch capscrew at the upper right end of the heater core.
  • Page 49 Table 4-6. R-134a Temperature - Pressure Chart Temperature Vacuum Temperature Pressure   “/hg Kg/cm@ @ @ @   Psig Kg/cm@ @ @ @ --40 --40 14.6 37.08 0.49 24.5 1.72 1.69 12.3 31.25 0.42 26.1 1.84 1.80 --30 --34 24.64 0.33...

  • Page 50: Electrical Schematic Diagrams

    ELECTRICAL SCHEMATIC DIAGRAMS 5.1 INTRODUCTION This section contains Electrical Schematic Diagrams covering the Models listed in Table 1-1. Contact your Carrier Transicold service representative or call the technical hot line at 800--450--2211 for a copy of the schematic for your specific model.

  • Page 51: Electrical Schematic Diagram Legend And Symbols

    THRU THRU COACH INTERFACE PACKARD CONNECTOR CONNECTOR Figure 5-1. Electrical Schematic Diagram Legend and Symbols (Based On Drawing No. 62-10907 Rev---) T-312...

  • Page 52: Electrical Schematic Diagram

    NOTE In 2003, early production units were retrofitted with diodes. If servicing a unit that is not wired as shown above, the unit should be retrofitted. Contact Carrier Service Engineering. See Figure 5-1 for legend and symbols. Figure 5-2. Electrical Schematic Diagram, Sheet 1 of 2 (Based On Drawing No.
  • Page 53 Figure 5-3. Electrical Schematic Diagram, Sheet 2 of 2 (Drawing No. 62-10907 Rev---) T-312...

  • Page 54: Electrical Schematic Diagram

    Figure 5-4. Electrical Schematic Diagram (Contact vehicle manufacturer for a specific diagram) T-312...
  • Page 55 INDEX Heating Flow Cycle, 1-11 Air Conditioning Refrigerant Cycle, 1-12 Humidity Control, 2-5 Air Filter, 3-6, 4-14 Humidity Sensor, 4-11, 4-12 Checking For Noncondensibles, 4-6 Installing Manifold Guages, 4-2 Checking High Pressure Switch, 4-7 Introduction, 1-1 Checking Refrigerant Charge, 4-6 Compressor, 1-3, 1-4 Compressor Oil Level, 4-10 Compressor Re--install, 4-9...
  • Page 56 INDEX Safety Devices, 1-10 Temperature Pressure Chart, 4-15 Safety Summary, General, i Schematic Diagram, 5-3, 5-4, 5-5 Temperature Sensor, 4-11 Servicing Motor Brushes, 4-12 Thermostatic Expansion Valve, 4-7 Suction and Discharge Service Valves, 4-1 Superheat -- Check/Measure, 4-8 TroubleShooting, 3-1 System Pumpdown, 4-2 System Service, 4-1 Troubleshooting Proceedures, 3-5...

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