Carrier G Series Heating Service manual

Carrier
Transicold
Transport
Air Conditioning
68G5-102 SERIES
MCI G MODEL COACH
Operation
& Service
T-310 Rev-A
OPERATION AND
SERVICE MANUAL
BUS
AIR CONDITIONING
EQUIPMENT
Model 68G5-102 Series
for
MCI G Model Coach
Carrier Transicold. A member of the United Technologies Corporation family. Stock symbol UTX.
Carrier Transicold Divsion, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221 U. S. A.
2002 CarrierCorporation D Printed in U. S. A. 0602
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 CO2 (never use water).
Safety - 1
T-310
SPECIFIC WARNINGS AND CAUTIONS
CAUTION
Do not under any circumstances attempt to service the microprocessor. Should a problem develop with the microprocessor, replace it.
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
READ THE ENTIRE PROCEDURE BEFORE BEGINNING WORK. PARK THE COACH
ON A LEVEL SURFACE, WITH PARKING BRAKE APPLIED. TURN MAIN ELECTRICAL DISCONNECT SWITCH TO THE OFF POSITION.
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.
CAUTION
Care Must Be Taken To Ensure That The Manifold Common Connection Remains Immersed
In Oil At All Times Or Air And Moisture Will Be Drawn Into The System.
WARNING
EXTREME CARE MUST BE TAKEN TO ENSURE THAT ALL THE REFRIGERANT
HAS BEEN REMOVED FROM THE COMPRESSOR CRANKCASE OR THE RESULTANT PRESSURE WILL FORCIBLY DISCHARGE COMPRESSOR OIL.
T-310
Safety - 2
TABLE OF CONTENTS
Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
SAFETY SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
SPECIFIC WARNINGS AND CAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.1 Condenser Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.2 Compressor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.3 Evaporator Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.3 System Operating Controls And Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.3.1 Other Carrier Supplied Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.4 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.5 ELECTRICAL SPECIFICATIONS - WOUNDFIELD MOTORS . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.6 ELECTRICAL SPECIFICATIONS-MAIN CONTROLLER INPUT SENSORS AND
TRANSDUCERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.7 SAFETY DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
1.8 HEATING (ENGINE COOLANT) FLOW CYCLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
1.9 AIR CONDITIONING REFRIGERANT CYCLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 STARTING, STOPPING AND OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1.1 Power to Logic Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1.2 Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1.3 Driver’s Area / Parcel Racks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1.4 Self-Test and Diagnostics (Check for Errors and/or Alarms) . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.1.5 Shut Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2 PRE--TRIP INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3 MODES OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3.1 Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3.2 Cooling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3.3 Heating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3.4 Circulation Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3.5 Vent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.6 Compressor Unloader Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.7 Evaporator Fan Speed Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.8 Condenser Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.9 Compressor Clutch Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.10 Liquid Line Solenoid Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.3.11 Alarm Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.3.12 Hour Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1 SELF DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1.1 System Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2 SYSTEM ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.1 Alarm Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.2 Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.3 Alarm Queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
i
T-310 Rev-
TABLE OF CONTENTS - Continued
Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
3.2.4 Alarm Clear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 MICROPROCESSOR DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 Diagnostic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3 Test Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1 System Will Not Cool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.2 System Runs But Has Insufficient Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.3 Abnormal Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.4 Abnormal Noise Or Vibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.5 Control System Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.6 No Evaporator Air Flow Or Restricted Air Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.7 Expansion Valve Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.8 Heating Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 MAINTENANCE SCHEDULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 SUCTION AND DISCHARGE SERVICE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 INSTALLING MANIFOLD GAUGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 PUMPING THE SYSTEM DOWN OR REMOVING THE REFRIGERANT CHARGE . . . . . .
4.4.1 System Pumpdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.2 Removing the Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.3 Refrigerant Removal From An Inoperative Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.4 Pump Down An Operable Compressor For Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5 REFRIGERANT LEAK CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 EVACUATION AND DEHYDRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.3 Procedure for Evacuation and Dehydrating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 ADDING REFRIGERANT TO SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.1 Checking Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.2 Adding Full Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.3 Adding Partial Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8 CHECKING FOR NONCONDENSIBLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9 CHECKING AND REPLACING HIGH PRESSURE CUTOUT SWITCH . . . . . . . . . . . . . . . . . .
4.9.1 Checking High Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9.2 Replacing High Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.10 FILTER-DRIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.10.1 To Check Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.10.2 To Replace Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11 THERMOSTATIC EXPANSION VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.1 Replacing the Power Head/Bulb Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.2 Replacing the Expansion Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.3 Check/Measure Superheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.12 MODEL 05G COMPRESSOR MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.12.1 Removing the Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T-310 Rev-
ii
3-1
3-1
3-3
3-3
3-3
3-6
3-6
3-6
3-6
3-6
3-7
3-7
3-7
3-7
4-1
4-1
4-1
4-2
4-2
4-2
4-3
4-3
4-3
4-3
4-4
4-4
4-4
4-4
4-6
4-6
4-6
4-6
4-6
4-7
4-7
4-7
4-7
4-7
4-7
4-7
4-8
4-8
4-9
4-9
4-9
TABLE OF CONTENTS - Continued
Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
4.12.2 Compressor Oil Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
4.12.3 Adding Oil with Compressor in System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
4.12.4 Adding Oil to Service Replacement Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4.12.5 Removing Oil from the Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4.13 TEMPERATURE SENSOR CHECKOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4.14 SUCTION AND DISCHARGE PRESSURE TRANSDUCER CHECKOUT . . . . . . . . . . . . . . . 4-12
4.15 REPLACING SENSORS AND TRANSDUCERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
4.16 SERVICING PASSENGER EVAPORATOR AIR FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
4.17 SERVICING PASSENGER EVAPORATOR MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
4.18 SERVICING PASSENGER EVAPORATOR MOTOR BRUSHES . . . . . . . . . . . . . . . . . . . . . . 4-12
4.19 SERVICING THE PASSENGER EVAPORATOR/HEATER COIL . . . . . . . . . . . . . . . . . . . . . . 4-12
4.20 SERVICING THE CONDENSER COIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.21 SERVICING THE CONDENSER MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.22 SERVICING CONDENSER MOTOR BRUSHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.23 Servicing the Driver Evaporator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.23.1 Access(Bottom) Cover Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.23.2 Blower Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.23.3 Coolant/Solenoid Valve Coil Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4.23.4 Air Filter Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4.23.5 Removal of Evaporator/Heater Core Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4.23.6 RAM Air Actuator Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4.24 LOGIC BOARD CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
ELECTRICAL SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
LIST OF ILLUSTRATIONS
Figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
Figure 1-1. Coach Cutaway View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Figure 1-2. Condenser Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Figure 1-3. Compressor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Figure 1-4. Driver Evaporator Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Figure 1-5. Passenger Evaporator Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Figure 1-6. System Operating Controls (upper left hand switch panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Figure 1-7. Micromate Control Panel (GLI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Figure 1-8. Micromate Control Panel (Standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Figure 1-9. Relay Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Figure 1-10. Logic Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Figure 1-11. Electrical Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Figure 1-12. Heating System Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Figure 1-13 Air Conditioning Refrigerant Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Figure 2-1 Capacity Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Figure 4-1. Suction or Discharge Service Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Figure 4-2. Manifold Gauge Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Figure 4-3. Compressor Service Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Figure 4-4. Refrigerant Service Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
iii
T-310 Rev-
LIST OF ILLUSTRATIONS - Continued
Figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
Figure 4-5. Checking High Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Figure 4-6. Thermostatic Expansion Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Figure 4-7. Hermetic Thermostatic Expansion Valve Brazing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Figure 4-8. Thermostatic Expansion Valve Bulb and Thermocouple Installation . . . . . . . . . . . . . . . . . . . 4-9
Figure 4-9. Removing Bypass Piston Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Figure 4-10. O5G Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Figure 5-1. Electrical Schematic Diagram legend and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Figure 5-2. Wiring Schematic - Power Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Figure 5-3. Wiring Schematic - Logic/Relay Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Figure 5-3. Wiring Schematic - Driver Evaporator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Figure 5-4. Wiring Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
LIST OF TABLES
Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page
Table 1-1. Part (Model) Number Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Table 1-2. Additional Support Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Table 1-3. Safety Devices (Within Carrier Supplied Equipment) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
Table 2-1. Evaporator Fan Speed Relay Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Table 3-1 Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Table 3-2 Alarm Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Table 3-3. Controller Test List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Table 3-4. Parameter Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Table 3-5. General System Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Table 4-1. Temperature Sensor (AT, TSC, TSD and TSR) Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Table 4-2. Suction and Discharge Pressure Transducer (SPT and DPT) Voltage . . . . . . . . . . . . . . . . . 4-12
Table 4-3. Logic Board Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Table 4-4. Torque Ratings - ORS Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Table 4-5. R-134a Temperature - Pressure Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
T-310 Rev-
iv
SECTION 1
DESCRIPTION
1.1 INTRODUCTION
consist of a condenser, a main evaporator and heater,
driver evaporator and heater, compressor assembly,
main control panel, driver display panel, and
temperature sensors.
This manual contains Operating and Service
Instructions and Electrical Data for the Model
68G5-102 Coach Air Conditioning and Heating
equipment furnished by Carrier Transicold Division for
the MCI G-Series Intercity coach. Table 1-1 provides a
part (model) number chart.
The 68G5 air conditioning and heating equipment
interfaces with electrical cabling, refrigerant piping,
engine coolant piping, ductwork and other components
furnished by the coach manufacturer to complete the
system.
The Model 68G5-102 equipment (see Figure 1-1)
MODEL
NUMBER
CONTROL
68G5-102
68G5-102-1
68G5-102-2
68G5-102-3
Reheat
Reheat
Reheat
Reheat
Table 1-1. Part (Model) Number Chart
CONDENSER
DRIVER
EVAPORATOR
KIT
DISPLAY
MOTOR
Aluminum
Aluminum
Copper
Copper
Standard
GLI
Standard
GLI
Wound Field
Wound Field
Wound Field
Wound Field
CONDENSER
MOTOR
Permanent Magnet
Permanent Magnet
Permanent Magnet
Permanent Magnet
MANUAL/FORM NUMBER
Table 1-2. Additional Support Manuals
EQUIPMENT COVERED
TYPE OF MANUAL
62--02756
T--200PL
O5G Compressor
O5G Compressor
Operation and Service
Parts List
DRIVER
RETURN AIR
TEMPERATURE
SENSOR
MIICROMATE
DISPLAY
PANEL
PASSENGER
EVAPORATOR
ASSEMBLY
*PARCEL RACK
EVAPORATOR
ASSEMBLY
(OPTIONAL)
PASSENGER
RETURN AIR
TEMPERATURE
SENSOR
DRIVER
EVAPORATOR
ASSEMBLY
AMBIENT
TEMPERATURE
SENSOR
MAIN
CONTROL
PANEL
CONDENSER
ASSEMBLY
*ENGINE
COOLANT
SHUT-OFF
VALVES
*INDICATES COMPONENTS FURNISHED
BY THE COACH MANUFACTURER
*BYPASS
HEAT
VALVE
*AUXILIARY
HEATER
COMPRESSOR
ASSEMBLY
Figure 1-1. Coach Cutaway View
1-1
T-310
1.2 GENERAL DESCRIPTION
noncondensibles from the liquid refrigerant before it
enters the thermal expansion valves in the evaporator
assemblies.
1.2.1 Condenser Assembly
The condenser assembly (See Figure 1-2) includes a
condenser coil, fan and motor assemblies, filter-drier,
receiver, liquid line solenoid valve, liquid line shut off
valve, king valves and a discharge check valve.
The condenser coil provides a heat transfer surface for
condensing refrigerant gas at a high temperature and
pressure into a liquid at high temperature and pressure.
The condenser fans circulate ambient air across the
outside of the condenser tubes at a temperature lower
than refrigerant circulating inside the tubes; this results
in condensing the refrigerant into a liquid. The
filter-drier
removes
moisture
and
other
2
3
The receiver collects and stores liquid refrigerant. The
receiver is fitted with upper and lower liquid level sight
glasses to determine refrigerant liquid level. The
receiver is also fitted with a fusible plug which protects
the system from high refrigerant pressures induced by
extreme high temperatures. The liquid line solenoid
valve closes when the system is shut down to prevent
flooding of coils with liquid refrigerant and to isolate
the filter-drier for servicing when the compressor is shut
down. The king valves and liquid line shut off valve
enable servicing of the condenser assembly.
5
4
6
10
2
11
1
7
8
9
14
23
15
22
16
13
21
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
20
19
18
12
17
Condenser Fan Motor CM1
Condenser Support Brace
Fan Blade
Fan Guard
Refrigerant Outlet Fitting (Parcel Rack)
Refrigerant Inlet Fitting with O–Ring
Discharge Check Valve
Condenser Fan Motor CM2
Discharge Line Shutoff Valve
Liquid Line Shut-off Valve (Parcel Rack)
Condenser Coil Assembly
Refrigerant Outlet Fitting (Main-Driver)
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Receiver
CFR2 (+) Junction Block
CFR2 (--) Junction Block
Receiver Sightglass
Fusible Plug
Liquid Line Shutoff (King) Valve
Model/Serial No. Nameplate
Filter-Drier
Liquid Line Solenoid Valve (Main)
CFR1 (--) Junction Block
CFR1 (+) Junction Block
Figure 1-2. Condenser Assembly
1.2.2 Compressor Assembly
suction and discharge pressure transducers, suction and
discharge servicing (charging) ports and electric
solenoid unloaders.
The compressor assembly (See Figure 1-3.) includes
the refrigerant compressor, clutch assembly, suction
and discharge service valves, high pressure switch,
T-310
1-2
1
2
3
4
5
6
7
8
9
DRIVE END VIEW
7
21
22
PUMP END VIEW
18
17
16
15
14
20
10
13
24
1.
2
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
ROADSIDE VIEW
23
19
Suction Pressure Port
Bracket, Belt Guard
Weatherpack Clutch Coil Connector
Discharge Valve Connection, Size 20 ORS
Discharge Service Valve
Discharge Valve Charging Port
Electric Solenoid Unloader
Compressor Oil Pump
Oil Drain Plug
Electric Solenoid Unloader Connectors
High Pressure Switch
Suction Pressure Transducer
12
11
TOP VIEW
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Discharge Pressure Transducer
Capscrew
Lockwasher
Special Washer
Lock Nut
Key
Clutch Assembly
Suction Service Valve
Suction Valve Connection, Size 24 ORS
Suction Valve Charging Port
Oil Fill Plug
Oil Level Sightglass
Figure 1-3. Compressor Assembly
The compressor raises the pressure and temperature of
the refrigerant gas and forces it into the condenser tubes.
The clutch assembly provides a means of belt driving
the compressor by the coach engine. The suction and
discharge service valves enable servicing of the
compressor. Suction and discharge access (charging)
ports mounted on the service valves enable connection
of charging hoses for servicing of the compressor, as
well as other parts of the refrigerant circuit. Transducers
convert refrigerant pressures into electrical signal
inputs which are sent to the main controller. The high
pressure switch (HPS) is a normally closed switch, its
contacts open on a pressure rise to shut down the system
when abnormally high refrigerant pressures occur. The
electric unloaders provide a means of controlling
compressor capacity, which enables control of
temperature inside the coach. For more detailed
information on the O5G compressor, refer to the
Operation and Service Manual number 62-02756.
1-3
T-310
1.2.3 Evaporator Assemblies
evaporator coils. The heating coils provide a heat
transfer surface for transferring heat from engine
coolant circulating inside the tubes to air circulating
over the outside surface of the tubes, thus providing
heating for the passenger and driver zones when
required. The evaporator heat valve (EHV) controls the
flow of engine coolant supplied to the heating coils. The
fans circulate the air over the coils. The air filters filter
dirt particles from the air before the air passes over the
coils. The condensate drain connections provide a
means for disposing of condensate collected on the
evaporator coils during cooling operation.
The evaporator assemblies include the driver zone
evaporator assembly (See Figure 1-4), the passenger
zone evaporator assembly (See Figure 1-5), and two
parcel rack evaporator assemblies (optional equipment
supplied by the coach manufacturer).
The evaporator coils provide a heat transfer surface for
transferring heat from air circulating over the outside
surface of the coil to refrigerant circulating inside the
tubes; thus providing cooling for the passenger and
driver zones when required. The thermal expansion
valves meter the flow of refrigerant entering the
TOP VIEW
SIDE VIEW (EXPOSED)
23
10
11
12
13
14
15
22
16
17
20
19
21
FRONT VIEW
18
SIDE VIEW
4
3
5
1
6
7
9
2
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Air Filter Access Door
Condensate Drain Connections
Fresh Air Damper Door
Fresh Air Damper Door Actuator
Nameplate
Heat Valve Controller
Positive Battery Stud
Control Circuit Connector
Ground Stud
Air Bleed Valve
Heater Outlet
Heater Inlet
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
8
Heater Control Valve
Suction Outlet Connection, 1-7/16 ORS
Liquid Inlet Connection, Size 11/16 ORS
Liquid Line Solenoid Valve
Driver Evaporator Power Relay
Thermal Expansion Valve
Coolant Drain Valve
Driver Evaporator Fan/Motor Assembly
Motor Speed Controller
Evaporator/Heater Coil Assembly
Air Filter
Figure 1-4. Driver Evaporator Assembly
The driver zone evaporator assembly includes an
evaporator/heater coil assembly, a liquid line solenoid
T-310
valve (LLSV), a thermal expansion valve (TXV), an
evaporator heat valve (EHV), a heat valve controller,
1-4
two fan/motor assemblies with motor speed controllers,
an air filter, a fresh air damper, and two condensate drain
connections. The evaporator motors speeds are variable
and controlled manually through a rheostat. The
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
evaporator heat valve (EHV) is also controlled with a
rheostat. The liquid line solenoid valve (LLSV) and the
fresh air damper damper door are activated through the
main controller.
1
Heater Coil Outlet Connection, 7/8 OD
Heater Coil Inlet Connection, 7/8 OD
Heater Coil Air Bleed Valve
Driver’s Evaporator Liquid Line Connection,
1-3/16-12 x 5/8 ORS
Refrigerant Suction Outlet Connection,
2-12 x 1-3/8 ORS
Air Filter
Evaporator/Heater Coil Assembly
Thermal Expansion Valve
Suction Temperature Sensor
Suction Temperature Sensor Connector
Refrigerant Liquid Inlet Connection,
1-14 x 5/8 ORS
Condensate Drain Connection (3)
Coolant Drain Valve
Evaporator Motor Overload Connection
2-Speed Motor
Blower(Fan) Housing
Lower Transition Duct
Main Power Wire Harness
Coil Mount Bracket
29
Thermal Expansion Valve Bulb
Service Port
28
Support Bracket
Removable Flange
Electrical Connector
Negative Stud
Positive Stud (EFR)
Positive Stud (ESR)
Curbside Transition Duct
Roadside Transition Duct
2
3
4
ROAD
SIDE
CURB
SIDE
5
6
17
7
16
8
15
9
10
11
14
18
13
12
27
26
25
24
20
Model/Serial
Number Plate
19
23
FRONT OF
COACH
19
22
21
Figure 1-5. Passenger Evaporator Assembly
The passenger evaporator assembly includes an
evaporator/heater coil assembly, a thermal expansion
valve (TXV), a fan and fan motor assembly, an air filter,
and three condensate drain connections. The fan motor
is a two-speed design with low and high speeds.
Evaporator fan relays (EFRL and EFRH) change
passenger zone evaporator fan speed upon receipt of a
signal from the main controller. The evaporator heat
valve (EHV) for the passenger evaporator is supplied by
the coach builder, installed in the piping outside the
evaporator assembly, and is controlled by the main
controller.
1-5
T-310
1.3 System Operating Controls And
Components
provide refrigeration as required. The compressor is
fitted with cylinder unloaders to match compressor
capacity to the bus requirements. Once interior
temperature reaches the desired set point, the system
may operate in either the clutch cycle or reheat mode(set
at the factory, choosen as part of the purchase
agreement). A controller programmed for reheat will
maintain compressor operation and open the heat
valve(EHV) to allow reheating of the return air. In the
reheat mode interior temperature is maintained at the
desired set point while additional dehumidification
takes place. A controller programmed for clutch cycle
will de--energize the compressor clutch and allow the
system to operate in the vent mode until further cooling
is required.
There are five controls on the driver’s station which
affect the operation of the Carrier supplied equipment
covered by this manual. These controls include two
rocker switches, two slide switches, and the Micromate
Control Panel. (Figure 1-6)
The first rocker switch (1 Figure 1-6) is the drivers
On/Off/Defrost switch which controls the power to the
control circuit for the entire system. The first slide
switch (2) is labeled the Defrost Switch. This switch
controls the driver evaporator blower motor speed. The
second slide switch (3) is labeled the Heat Switch. This
switch controls the driver evaporator coolant valve. The
second rocker switch (4) is labeled the Parcel Rack.
This switch will activate the parcel rack evaporators if
the passenger evaporator is in operation.
The fifth control is the Micromate Control Panel
(Figure 1-7 or Figure 1-8) which operates the Carrier
Transicold Micromax microprocessor controller, logic
board (Figure 1-10), relay board (Figure 1-9), circuit
breakers and relays (Figure 1-11). The logic board
regulates the operational cycles of the system by
energizing or de--energizing components in response to
deviations in interior temperature. Modes of operation
include Auto, Cool, Heat and Vent.
The Micromate Control Panel (supplied in one of two
configurations) is installed in the upper left hand switch
panel. One configuration (Figure 1-7) will allow the
driver to turn the system on and off, access outside and
interior return air temperatures, and adjust interior
temperature setpoint. With this configuration, system
diagnostics will need to be performed with the
Micromate
Diagnostic
Service
Tool
(P/N
76-62124--01). The other configuration (Figure 1-8)
will perform the same functions and also allow the
driver to control all the system functions manually. In
addition this configuration will allow the service
technician to view system parameters and alarms.
With the Micromate in the AUTO mode, the logic board
will cycle the system between the operating modes as
required to maintain desired set point temperature.
In the VENT mode the evaporator fans are operated to
circulate air in the bus interior.
In the HEAT mode the heat valve(EHV), the OEM
supplied boost pump and auxiliary heater are energized.
The evaporator fans operate to circulate air over the
evaporator coil in the same manner as the vent mode.
In the COOL mode the compressor is energized while
the evaporator and condenser fans are operated to
T-310
1.3.1 Other Carrier Supplied Items
Other Carrier supplied items include driver and
passenger interior return air temperature sensors, and an
ambient temperature sensor. The temperature sensors
provide input to the controller on temperature
conditions in the applicable zone.
1
2
3
4
5
1.
2.
3.
4.
5.
System On/Off/Defrost
Defrost(Driver’s Evap. Blower)
Heat(Driver’s Evap. Coolant Valve)
Parcel Rack On/Off
Micromate Control Panel
Figure 1-6. System Operating Controls
(upper left hand switch panel)
1-6
1
1.
2.
3.
2
3
5
4
Display
DOWN Button - decrease selection
UP Button - increase selection
4.
5.
TEMPERATURE (Inside/Outside) Button
ON/OFF Button
Figure 1-7. Micromate Control Panel (GLI)
1
2
3
4
5
6
7
11
1.
2.
3.
4.
5.
6.
10
9
8
7.
8.
9.
10.
11.
Display
DOWN Button - decrease selection
UP Button - increase selection
Vent (Only) Button
AUTO Button (Automatic Control)
COOLING (Only) Button
HEAT (Only) Button
FAN SPEED Button
FRESH AIR Button
TEMPERATURE (Inside/Outside) Button
ON/OFF Button
Figure 1-8. Micromate Control Panel (Standard)
1-7
T-310
Model/Serial
Number
d. LEDS
D 2 Relay K2 output active (evaporator fan high
speed relay energized)
D 6 Relay K1 output active (evaporator fan relay
energized)
D17 F1 fuse open (fresh air damper).
D18 F3 fuse open (evap. fan).
D26 Relay K3 output active (condenser fan relay
energized)
D30 Relay K8 output active (condenser fan high
speed relay energized)
D31 F9 fuse open (condenser fans).
D38 F2 fuse open (unloader #1).
D47 F5 fuse open (unloader #2).
D51 A/C clutch and liquid line solenoid valve
output active.
D54 Unloader 1 output active.
D57 Unloader 2 output active.
D60 Fresh air output active.
D61 F6 fuse open (heat valve).
D63 Heat valve output active.
D66 Fault output active.
D68 F4 fuse open (fault light).
D69 circulation pump output active.
D72 Driver LSV active.
D77 F8 fuse open (driver LLSV).
D83 F10 fuse open (circulation pump).
D90 F7 fuse open (compressor clutch).
a. Relays
K1 Energizes evaporator fans
K2 Energizes evaporator fans in low speed
(not energized in low speed).
K 7 Energizes condenser fans
K 8 Energizes condenser in high speed
(not energized in low speed).
K13 Energizes the A/C clutch and liquid line
solenoid valve.
K14 Energizes unloader 1.
K15 Energizes unloader 2.
K16 Energizes fresh air damper.
K17 Energizes heat valve (EHV).
K18 Energizes the fault light output.
K19 Energizes the boost pump and heat valve.
K20 Energizes drivers liquid solenoid valve.
K21 Energizes evaporator fans in high speed.
K22 Energizes evaporator fans in low speed.
K23 Energizes condenser fans in high speed.
K24 Energizes condenser fans in low speed.
b. Connectors
JA Coach interface
JB Boost pump.
JC Logic board connector.
c. Fuses
F1--F6 5 Amp
F7
7.5 Amp
F8--F9 5 Amp
F10
15 Amp
Figure 1-9. Relay Board
T-310
1-8
J1
J2
J3
J4
J5
J6
J7
Logic board power in
Micromate Display interface.
Manual control inputs.
Interlock Inputs (WTS, etc.)
Relay board interface.
Sensor inputs (Thermistors, etc.).
Diagnostics interface (RS232, DB9)
D2 Blinks once per second in normal operation.
On steady to indicate alarms detected.
D3 Off In normal operation, blinks out alarm
codes (2 digits each) when alarms detected.
A-P Configuration Jumpers
Figure 1-10. Logic Board
1-9
T-310
5
3
6
4
2
1
NEG
POS
7
19
K2
K14
K16
K1
K15
K18
K13
K17
EFR
8
9
.
ESR
18
3
K8
K20
K7
K19
CFR1
17
CB1
CSR
CFR2
16
15
4
10
11
5
6
CB2
12
14
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Power Stud (Ground)
Main Power Stud (Positive)
Control Panel Main Harness
35 Pin Connector Plug
Evap. Motor Overload Connector
Coach Interface Connector (16 Pin)
Relay Board
Relay
Fuse
Ribbon Cable (Logic Module to Relay Board)
13
11.
12.
13.
14.
15.
16.
17.
18.
19.
Logic Module
Logic Module to Driver Display Harness
CB1, Passenger Evap. Motor (110 Amp.)
CB2, Condenser Motors (110 Amp.)
Condenser Speed Relay (High Speed)
Condenser Fan Relay #2
Condenser Fan Relay #1
Passenger Evaporator High Speed Contactor
Passenger Evaporator Relay
Figure 1-11. Electrical Control Panel
T-310
1-10
c. Condenser Fan Motor
Bearing Lubrication: Shell Dolium R
Horsepower: 0.8 hp (1.072 kw)
Full Load Amps (FLA):
High Speed: 27
Low Speed: 20
Operating Speed:
High Speed: 1800 rpm
Low Speed: 900 rpm
Voltage: 24 vdc
1.4 REFRIGERATION SYSTEM COMPONENT
SPECIFICATIONS
e. Refrigerant Charge
R-134a: 27 lb (12 kg)
f. Compressor
Model: 05G
No. of Cylinder: 6
Weight (Dry): 145 lb (66 kg) including clutch
Oil Charge:
New Compressor: 5.8 pints (2.7 liters)
Replacement Compressor: 5 pints (2.4 liters)
Oil Level:
Level in sight glass between bottom of glass and
middle of glass on compressor crankcase
(curbside)
Approved Compressor Oils - R-134a:
Castrol: Icematic SW68C
Mobil: EAL Arctic 68
ICI: Emkarate RL68H
g. Thermostatic Expansion Valve (R-134a):
1. Passenger Evaporator:
Superheat Setting (Nonadjustable): 12 to 18_F
(6.7 to 10.1_C)
MOP Setting: 65 psig (448 kPa)
2. Driver Evaporator:
Superheat Setting (Nonadjustable): 5_F (-15_C)
MOP Setting: 65 psig (448 kPa)
h. High Pressure Switch (HPS) (R-134a):
Opens at: 350 10 psig (2.7 mPa 69 kPa)
Closes at: 240 10 psig (2.0 mPa 69 kPa)
1.6 ELECTRICAL SPECIFICATIONS-MAIN
CONTROLLER INPUT SENSORS AND
TRANSDUCERS
a. Suction and Discharge Pressure Transducer
Supply Voltage: 4.5 to 5.5 vdc (5 vdc nominal)
Input Range: --6.7 to 450 psig (--46.2 kPa to 3.1 mPa)
Output: 1.446 vdc at 100 psig
(See Table 4-2 for calculations.)
b. Temperature Sensors
Input Range: --52.6 to 158_F (--47 to 70_C)
Output: NTC 10K ohms at 77_F (25_C)
(See Table 4-1 for calculations.)
1.5 ELECTRICAL SPECIFICATIONS - WOUND
FIELD MOTORS
a. Evaporator/Heater Blower (Fan) Motor
Bearing Lubrication: Factory Lubricated (additional
grease not required)
Horsepower:
High Speed: 2.0 (1.49 kw)
Low Speed: 0.9 (0.67 kw)
Full Load Amps (FLA):
High Speed: 70
Low Speed: 32
Operating Speed:
High Speed: 1600 rpm
Low Speed: 1250 rpm
Voltage: 27 vdc
b. Driver Evaporator/Heater Blower (Fan) Motor
Bearing Lubrication: Factory Lubricated (additional
grease not required)
Full Load Amps (FLA): 11
Operating Speed:
High Speed: 2700 rpm
Low Speed: 1100 rpm
Voltage: 24 vdc
1-11
T-310
1.7 SAFETY DEVICES
The high pressure switch (HPS) is installed in the
compressor center cylinder head and opens on a
pressure rise to shut down the system when high
pressure conditions occur. The switch is factory set to
open at 350 10 psig (2.4 mPa 69 kPa ) and to close at
240 10 psig (1.7 mPa 69 kPa).
During the A/C mode, HVAC system operation will
automatically stop if the HPS switch contacts open due
to an unsafe operating condition. Opening HPS contacts
de-energizes, through the main controller, the A/C
compressor clutch shutting down the system.
System components are protected from damage caused
by unsafe operating conditions with safety devices.
Safety devices installed in Carrier Transicold supplied
equipment include high pressure switch (HPS), the
fusible plug, and circuit breakers (CB1 and CB2). (See
Table 1-3.)
In addition, evaporator and condenser fan motors and
the main control box are protected independently
against high current draw by circuit breakers supplied
by the coach manufacturer. The evaporator fan motor is
also protected from high temperature with an internal
thermal protection switch.
c. Fuses and Circuit Breakers
The Relay Board is protected against high current by an
OEM supplied 150 amp fuse or circuit breaker.
Independent 110 amp circuit breakers protect each
motor circuit, while the output circuits are protected by
additional 5 to 15 amp fuses. During a high current
condition, the OEM breaker may open. When power is
removed from a device, a breaker alarm will be
generated. In addition the driver’s evaporator is
protected by an OEM supplied 30 amp. circuit breaker.
Fuse (F2), internal to the controller, protects the
controller 12 vdc supply circuit from excessive current
draw. Fuse (F3) protects the controller 24 vdc output
circuit from excessive current draw.
a. Thermal Switches
Evaporator Motor Overloads (EMOL)
d. Ambient Lockout
The evaporator fan motor is equipped with an internal
thermal protector switch. When a high temperature
condition occurs, the appropriate EMOL switch will
open to de-energize the corresponding evaporator fan
relay (EFR); this will prevent the evaporator fan motor
from operating.
The ambient temperature sensor, located near the driver
evaporator section, measures the inlet air temperature.
When the temperature is below the cut out set point the
compressor is locked out until the temperature rises
above the cut in setting. The set points will be
programmed to cut out at 25F (-3.9C) and cut in at
35F (1.7C). This setting protects the compressor from
damage caused by operation at low temperatures.
b. Pressure Switches
High Pressure Switch (HPS)
Table 1-3. Safety Devices (Within Carrier Supplied Equipment)
Unsafe Condition
Excessive current draw by driver
evaporator motors
Safety Device
Circuit Breaker
Manual Reset
Device Setting
30 amps
High compressor discharge
pressure
High Pressure Switch (HPS)
Opens at: 350 10 psig
(2.4 mPa 69 kPa )
Closes at: 240 10 psig
(1.7 mPa 69 kPa)
High refrigerant pressures
induced by extreme high
temperature
Fusible Plug
Melts to relieve pressure at
210_F
Does not close, replacement
necessary once blown
Excessive current draw by the
controller 12 vdc supply circuit
Fuse (F2)
Opens at 5 amps
Excessive current draw by the
controller 24 vdc output circuit
Fuse (F3)
Opens at 10 amps
Excessive current draw by
evaporator motor
Circuit Breaker (CB1)
Automatic Reset
110 amps
Excessive current draw by
condenser motor
Circuit Breaker (CB2)
Automatic Reset
110 amps
T-310
1-12
1.8 HEATING (ENGINE COOLANT) FLOW CYCLE
maintain required temperatures inside the coach.
Engine coolant (glycol solution) is circulated through
the heating circuit by the engine and auxiliary water
pumps. When the evaporator heat valve solenoid is
de-energized, the valve will open to allow engine
coolant to flow through the heater coil. (See
Figure 1-12.) The valve is normally open so that if a
failure occurs, the system will still be able to supply
heat.
Heating circuit components furnished by Carrier
Transicold include heater cores for the driver and main
evaporator assemblies and the evaporator heat valve
(EHV) for the driver evaporator assembly. Components
furnished by the coach manufacturer include auxiliary
heater(optional) and engine water pumps and hand
valves. The main controller automatically controls the
EHV valves during heating and reheat cycles to
DRIVER’S HEATER
DRIVER’S EHV
(N/O)
PASSENGER HEATER
* PASSENGER
EHV (N/O)
* AUXILIARY HEATER
* BOOST
PUMP
* SHUT-OFF
*ENGINE
* SHUT-OFF
*CHECKVALVE
*INDICATES COMPONENTS FURNISHED
* ENGINE COOLANT PUMP
BY THE COACH MANUFACTURER
Figure 1-12. Heating System Flow Diagram
1.9 AIR CONDITIONING REFRIGERANT CYCLE
tubes have fins designed to improve the transfer of heat
from the refrigerant gas to the air; this removal of heat
causes the refrigerant to liquefy, thus liquid refrigerant
leaves the condenser and flows to the receiver.
When air conditioning (cooling) is selected by the main
controller, the unit operates as a vapor compression
system using R-134a as a refrigerant. The main
components of the system are the reciprocating
compressor, air-cooled condenser coil, subcooler,
receiver, filter-drier, thermostatic expansion valves,
liquid line solenoid valves and evaporator coils. (See
Figure 1-13 .)
The receiver serves as a liquid refrigerant reservoir so
that a constant supply of liquid is available to the
evaporators as needed, and acts as an isolated storage
space when pumping down the system. The receiver is
equipped with sight glasses to observe the refrigerant
for correct charge level.
The compressor raises the pressure and the temperature
of the refrigerant and forces it through the discharge
line, through the check valve into the condenser tubes.
The condenser fan circulates surrounding air (which is
at a temperature lower than the refrigerant) over the
outside of the condenser tubes. Heat transfer is
established from the refrigerant (inside the tubes) to the
condenser air (flowing over the tubes). The condenser
The refrigerant leaves the receiver and then flows
through the subcooler, which subcools the refrigerant
before it enters the thermal expansion valves; this
reduces flash gas in the evaporator. From the subcooler,
the refrigerant passes through the liquid line service
valve, and then through a filter-drier which keeps the
refrigerant clean and free of water.
1-13
T-310
From the filter-drier, the liquid refrigerant then flows
through the main liquid solenoid valve to the passenger
evaporator thermal expansion valve and through the
driver solenoid valve and to the driver thermal
expansion valve. The solenoid valves open during
cooling to allow refrigerant to flow to the thermal
expansion valves. The main liquid solenoid valve and
closes during shutdown to isolate the refrigerant in the
receiver. The thermal expansion valves reduce the
pressure and temperature of the liquid and meters the
flow of liquid refrigerant to the evaporator to obtain
maximum use of the evaporator heat transfer surface.
evaporator air (flowing over the tubes) to the refrigerant
(flowing inside the tubes). The evaporator tubes have
aluminum fins to increase heat transfer from the air to
the refrigerant; therefore the cooler air is circulated to
the interior of the coach. Liquid line solenoid valves
close during shutdown to prevent refrigerant flow.
The low pressure, low temperature liquid that flows into
the evaporator tubes is colder than the air that is
circulated over the evaporator tubes by the evaporator
blower (fan). Heat transfer is established from the
When ventilation only is selected by the main
controller, only the evaporator fans function to circulate
air throughout the coach. The refrigerant cycle will
remain off.
The transfer of heat from the air to the low temperature
liquid refrigerant in the evaporator causes the liquid to
vaporize. This low temperature, low pressure vapor
passes through the suction line and returns to the
compressor where the cycle repeats.
DRIVER SOLENOID VALVE
(N/C)
TXV
TXV BULB
DRIVER EVAP. MODULE
TXV
BULB
TXV
PASSENGER EVAP. MODULE
MAIN LIQUID LINE
SOLENOID VALVE
(N/C)
PRESSURE
TAP
PARCEL LIQUID LINE
SOLENOID VALVE
FILTER DRIER
(N/C)
TXV
PARCEL EVAP.
LIQUID LINE
SHUT OFF VALVE
PARCEL
EVAP.
MODULE
LIQUID LINE
SERVICE VALVE
(N/C)
FUSIBLE
PLUG
TXV
RECEIVER
DISCHARGE
LINE SERVICE
VALVE
DISCHARGE
CHECK VALVE
CONDENSER MODULE
COMPRESSOR
Figure 1-13 Air Conditioning Refrigerant Flow Diagram
T-310
1-14
PARCEL
EVAP.
MODULE
SECTION 2
OPERATION
2.1 STARTING, STOPPING AND OPERATING
INSTRUCTIONS
2.1.1 Power to Logic Board
Before starting, electrical power must be available from
the coach power supply. The system components
receive power from two sources:
a. OEM SUPPLIED SWITCHES
An ON/OFF/DEFROST switch is supplied. In the
ON position the Micromate Control Panel and the
driver’s evaporator are fully functional. In the Off
position the driver’s evaporator is shut off, but the
Micromate Control Panel is functional. In the Defrost position, only the driver’s evaporator is functional.(Refer to Figure 1-6, item 1)
b. 24 vdc power for the microprocessor electronics is
supplied through the coach wiring harness.
c. 24 vdc power thru a 150 amp fuse in the battery
compartment supplies power for the clutch, compressor, unloader solenoids, evaporator and condenser assemblies; this power is controlled by the Logic
Board.
2.1.2 Starting
b. OEM SUPPLIED SWITCHES
An ON/OFF/DEFROST switch is supplied, place the
switch in the ON position to start the system in the automatic mode. (Refer to Figure 1-6, item 1)
CONTROL
PANEL
2 The Micromate Control Panel will signal the Logic
Board to perform start up when the ON/OFF/DEFROST switch is thrown (refer to 2.1.2.b.). Ensure
the AUTO button indicator is illuminated. If not,
press the AUTO button to place the system in the automatic mode. After the pre--trip inspection is completed, the switches may be set in accordance with
the desired control modes.
3 If cooling only, heating only or ventilation only is
desired, press the corresponding button (refer to
Figure 1-6) to illuminate the indicator light and
place the system in that mode of operation.
4 If low or high speed evaporator fan speed is desired,
press the FAN SPEED button to illuminate the indicator light and bring speed to the desired level.
5 To open or close the fresh air damper, press the
FRESH AIR button.
a. If the engine is not running, start the engine.
c. MICROMATE
Figure 1-7)
temperature is programmed, press the TEMPERATURE button so that the OUT SIDE AIR indicator is
illuminated. If the controller cycles back to the INSIDE AIR indicator, than the controller is programmed to display return air temperature. If the
controller does not automatically cycle back to the
return air indicator, than the controller is programmed to display set point temperature.
(GLI,
1 The Micromate Control Panel displays the set point
temperature or return air temperature.
2 The Micromate Control Panel will signal the Logic
Board to perform start up when the ON/OFF/DEFROST switch is thrown (refer to 2.1.2.b.).
3 To read interior or exterior temperature, press the
TEMPERATURE button to illuminate the indicator
light . After a short delay, the display will return to
the default set point or return air temperature reading.
4 Setpoint may be changed by pressing the UP or
DOWN arrow button. The UP button will increase
the setpoint temperature and the DOWN button will
decrease the setpoint temperature.
d. MICROMATE CONTROL PANEL (Standard,
Figure 1-8)
If this control panel is supplied, it is suggested the
system be started in the automatic mode.
1 The Micromate Control Panel Display may be programmed to display the set point temperature or return air temperature. To determine which display
2-1
6 To read interior or exterior temperature, press the
TEMPERATURE button to illuminate the indicator
light and bring the display to the desired temperature
reading. After a short delay, the display will return to
the default set point or return air temperature reading.
7 Setpoint may be changed by pressing the UP or
DOWN arrow button. The UP button will increase
the setpoint temperature and the DOWN button will
decrease the setpoint temperature.
8 For additional Micromate operating data refer to
paragraph 3.3.
2.1.3 Driver’s Area / Parcel Racks
The driver’s evaporator is manually controlled with
four switches located on the driver’s control panel.
Before starting, power must be available to the main
system. For cooling the Micromate must be On. For
heating the engine must be running and up to operating
temperature.
a. If the engine is not running, start the engine.
b. OEM SUPPLIED SWITCHES
An ON/OFF/DEFROST switch is supplied, place the
switch in the ON position if air conditioning of the
driver’s area is desired. If heating/defrosting of the
driver’s area is required, and conditioning of the passenger area is not required, place the switch in DEFROST.(Refer to Figure 1-6, item 1)
T--310
1 Two sliding switches are provided to control the
driver’s evaporator. The Defrost switch(Refer to
Figure 1-6, item 2) controls evaporator blower
speed. The Heat switch(Refer to Figure 1-6, item 3)
controls the amount of engine coolant that circulates
through the heater core.
2 One rocker switch (Refer to Figure 1-6, item 4)is
provided to control the optional parcel evaporators.
Activating this switch operates the blowers and liquid line solenoid valves of both parcel evaporators.
The parcel evaporators will function only if the main
evaporator is functioning.
2.1.4 Self-Test and Diagnostics (Check for Errors
and/or Alarms)
Self-test of the main Logic Board electrical circuit is
automatically initiated when the system is powered up.
If there is an error in the circuit, an alarm will be
indicated by flashing LED’s on the Logic Board. If a
Micromate is connected to the Logic Board, the error
code can also be read on the display. If there are no errors
in the circuit, system will operate normally and flash the
status LED at a one second interval. During normal
operation, the Logic Board monitors system operating
parameters for out of tolerance conditions. If an out of
tolerance condition occurs, ALARM will be indicated
through the code LED or on the Micromate display.
Refer to section 3 for definition of system errors and
alarms and general troubleshooting procedures.
2.1.5 Shut Down
Placing the ON/OFF/DEFROST switch in the OFF
position will shut down the system operation by
removing power to the Logic Board. Pressing the
Micromate ON/OFF button will shut off the passenger
evaporator.
NOTE
2.3 MODES OF OPERATION
The system is operated by a Carrier Transicold
Micromax microprocessor controller which consists of
a logic board (Figure 1-10), relay board (Figure 1-9),
and manual operator switches. The logic board
regulates operational cycles of the system by energizing
or de--energizing Relay Board relays in response to
deviations in interior temperature. The basic modes of
operation include Cooling, Heat and Vent. Refer to
Figure 2-1 and the following paragraphs for a
description of each mode.
Figure 2-1 shows the Logic Board actions at various
temperature deviations from setpoint. On rising
temperature, changes occur when the temperature rises
above Logic Board set points. On falling temperature,
changes occur when temperatures falls below Logic
Board set point. Note that the Logic Board reacts to
ambient temperatures as well as deviations from set
point, to allow for more precise temperature control.
The system will operate in these modes unless pressures
override the Logic Board settings.
2.3.1 Temperature Control
Temperature is controlled by maintaining the return air
temperature measured at the return air grills. (See
Figure 1-1 for approximate locations) The system
controller responds(averages) to both return air sensors.
2.3.2 Cooling Mode
Cooling is accomplished by energizing the compressor
and condenser fans, opening the liquid line solenoid
valve and closing the heating valve. Once interior
temperature reaches the desired set point, the system
may operate in the clutch cycle or reheat mode.
Selection of clutch cycle or reheat is factory
programmed in accordance with the coach purchase
specification.
A controller programmed for clutch cycle will
de--energize the compressor clutch and allow the system
to operate in the vent mode until further cooling is
required.
All operations described in this chapter beyond
this point must be performed by an HVAC
technician who has been trained on Carrier
system design. It is recommended that Carrier
Service or Engineering is contacted before any
control operation beyond chapter 2.1 is
attempted. Carrier is not responsible for
failures or
damage
resulting from
unauthorized changes.
A controller programmed for reheat will maintain
compressor operation and cycle the heat valve to allow
reheating of the return air. In the reheat mode interior
temperature is maintained at the desired set point while
additional dehumidification takes place.
2.3.3 Heating Mode
2.2 PRE--TRIP INSPECTION
After starting system, allow system to stabilize for ten to
fifteen minutes and check for the following:
a. Listen for abnormal noises in compressor or fan motors.
b. Check compressor oil level. (Refer to section 4.12.2)
c. Check refrigerant charge. (Refer to section 4.7.1 )
d. Ensure that self-test has been successfully performed
and that there are no errors or alarms indicated. (Refer
to section 2.1.4.)
T--310
2-2
In the heat mode the liquid line solenoid is closed and
the compressor and condenser fans are shut down. The
heat valve is opened to allow a flow of engine coolant
through the heat section of the evaporator coil. The
evaporator fans speed is varied as required to circulate
air over the evaporator coil based on the temperature
difference from setpoint.
Operation in the heating mode is controlled by the water
temperature switch (WTS). The switch prevents the
circulation of cooler air throughout the vehicle until
engine coolant temperature reaches 190F. The WTS is
located on the engine block of the vehicle and is
provided by the OEM.
REHEAT
COOL
HIGH SPEED
LOADED
AUTO
AUTO
(LESS THAN 45 DEGF AMBIENT)
3°F
COOL
HIGH SPEED
LOADED
3°F
COOL
HIGH SPEED
LOADED
COOLING
COOLING
(LESS THAN 45 DEGF AMBIENT)
3°F
COOL
HIGH SPEED
LOADED
3°F
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
HIGH SPEED
LOADED
3°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
LOW SPEED
2 CYLINDERS
1°F
SETPOINT
--1°F
--2°F
--3°F
--4°F
REHEAT 12.5%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 25%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 50%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
--2°F
--3°F
HEAT 100%
DUTY CYCLE
REHEAT 50%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 75%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
--2°F
HEAT 100%
DUTY CYCLE
--3°F
--4°F
HEAT
HEAT
REHEAT 12.5%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 25%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 50%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
--2°F
--3°F
REHEAT 50%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
REHEAT 75%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
--2°F
HEAT 100%
DUTY CYCLE
HEAT 100%
DUTY CYCLE
HEAT
HEAT
CYCLING
COOLING
AUTO
HEAT
3°F
COOL
HIGH SPEED
LOADED
3°F
COOL
HIGH SPEED
LOADED
3°F
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
2°F
2°F
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
1°F
1°F
SETPOINT
SETPOINT
VENT
VENT
VENT
--1°F
--1°F
--1°F
--2°F
--2°F
--2°F
HEAT
--3°F
--1°F
--1°F
--2°F
--2°F
HEAT
--3°F
HEAT
--3°F
--3°F
Figure 2-1 Capacity Control Diagram
2-3
T--310
2.3.4 Boost Pump
When the unit is in the heat mode, the boost pump relay
is energized, providing 24 VDC to activate the boost
pump(supplied by the coach manufacturer).
2.3.5 Vent Mode
In the vent mode the evaporator fans are operated to
circulate air in the coach interior without benefit of
either cooling or heating.
2.3.6 Compressor Unloader Control
When operating in cooling, the unloaders are used to
reduce system capacity as return air temperature
approaches set point. Operation of the unloaders
balances system capacity with the load and thereby
prevents overshoot from set point.
Relay Board mounted unloader outputs control the
capacity of the compressor by energizing or
de-energizing unloader solenoid valves. The model
05G compressor has three banks of two cylinders each.
Energizing a valve de-activates a bank of cylinders. The
outboard cylinder banks of the 05G are equipped with
unloader valves (UV1 and UV2), each controlling two
cylinders; this allows the 05G to be operated with two,
four or six cylinders.
Whenever the compressor is started, the unloaders are
energized for a 30 second delay time to reduce starting
torque. After the delay, unloaders may be de-energized.
Any subsequent changes between energizing and
de-energizing the unloaders for temperature control is
also staged for a preset delay time. Once an unloader is
energized for pressure control, it remains energized for
two minutes to prevent short cycling. Only one unloader
may change state at a time when staging is required.
Operating parameters for temperature control, suction
pressure control and discharge pressure control are as
follows.
a. Capacity Control
The unloaders are used to control system capacity by
controlling compressor capacity.
1 Compressor Unloader UV1 Relay. When return air
temperature falls to less than 2F (1.1C) above set
point unloader UV1 is energized. If temperature
rises to greater than 3F (1.7C) above set point,
UV--1 will be de--energized to place the compressor
at 100% capacity.
2 Compressor Unloader UV2 Relay. When return air
temperature falls to less than 1F (0.6C) above set
point unloader UV2 is energized. If temperature
rises to greater than 2F (1.1C) above set point,
UV--2 will be de--energized to place the compressor
at 66% capacity.
b. Suction Pressure
The unloaders are used to control suction pressure and
thereby prevent coil frosting:
T--310
2-4
1 Compressor Unloader UV1 Relay. When the suction
pressure decreases below 26 psig, unloader UV1 is
energized unloading a cylinder bank (two cylinders);
this output will remain energized until the pressure
increases to above 33 psig.
2 Compressor Unloader UV2 Relay. When suction
pressure decreases below 23 psig, unloader UV2 is
energized unloading the second compressor cylinder
bank; this output will remain energized until the
pressure increases to above 30 psig.
c. Discharge Pressure
Discharge pressure is also controlled by the unloaders:
1 Compressor Unloader UV1 Relay. When the discharge pressure increases above 330 psig, unloader
UV1 is energized; this output will remain energized
until the pressure decreases below 245 psig. Staging
is ignored during discharge pressure override.
2 Compressor Unloader UV2 Relay. When the discharge pressure increases above 330 psig, unloader
UV2 is energized; this output will remain energized
until the pressure decreases below 245 psig. Staging
is ignored during discharge pressure override.
NOTE
The controller will not allow both unloader operations to happen at the same time, but stages
the second unloader 30 seconds after the first if
discharge pressure exceeds 330 psig.
2.3.7 Evaporator Fan Speed Selection
Temperature control is the primary method of
determining the fan speed selection. The following
table indicates relay operational status for the various
fan motor states while Figure 2-1 provides Logic Board
speed selections at various deviations from set point.
Table 2-1. Evaporator Fan Speed
Relay Operation
STATE
Off
Low
High
HIGH
SPEED
RELAYS
EVAP FAN
RELAY
Off
Off
On
Off
On
On
2.3.8 Condenser Fan Control
The condenser fans are energized when the compressor
clutch output is energized. The fans are started in low
speed and will remain in low speed until the discharge
pressure increases to 190 PSIG. The fans will remain in
high speed until discharge pressure decreases below 135
PSIG. The fans will also be activated if a high pressure
alarm has been activated and operation has not been
locked out (refer to Table 3--2).
2.3.9 Compressor Clutch Control
The clutch coil will be de-energized if the suction
pressure decreases below 10 PSIG.
A belt driven electric clutch is employed to transmit
engine power to the air conditioning compressor.
De-energizing the clutch electric coil disengages the
clutch and removes power from the compressor. The
clutch will be engaged when in cooling and disengaged
when the system is off, in heating or during high and low
pressure conditions.
2.3.10 Liquid Line Solenoid Control
The clutch coil is prevented from engagement when the
ambient temperature is below ambient lockout setpoint.
The clutch coil will be de-energized if the discharge
pressure rises to the cutout setting of the compressor
mounted high pressure switch. The clutch coil will
energize when the discharge pressure falls to the reset
point of the compressor mounted high pressure switch.
2-5
The liquid line solenoid is energized (open) when the
compressor clutch is energized and de--energized
(closed) when the clutch is not.
2.3.11 Alarm Description
Alarm descriptions and troubleshooting procedures are
provided in section 3.
2.3.12 Hour Meters
Hour meter readings are available in the parameter code
list of the Micromate. The hour meters record the
compressor run time and the total time the evaporator
fans are on. The maximum hours is 999,999. Refer to
paragraph 3.3.2 for instructions on reading parameter
codes.
T--310
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
Figure 1-10) flash simultaneously. The Micromate
display will indicate errors with the code ER-#, where
“ER” is the error prefix and # is the error number.
A self test is performed by the Micromax Logic Board
each time the board is powered up. Errors, if any, will be
indicated and the unit will not be allowed to start. The
Table 3-1 Error Codes
CODE
NAME
DESCRIPTION
ER 1
Data Memory
Logic board data memory failure.
ER 2
Program Memory
Logic board program memory failure.
ER 3
A/D
A/D and multiplexer failure.
ER 4
Communication Failure
Failure in communication between the logic board and Micromate
control panel.
ER 5
Program Memory
Display program memory failure.
3.1.1 System Parameters
Pressing the up/down arrow keys will allow the user to
scroll up or down through the parameters. If no key is
pressed for 30 seconds this mode is exited and the
display will revert back to the default display. Pressing
the on/off key any time will exit this mode and the
display will again indicate the default. The parameters
are shown in Table 3-4. When scrolling through the
parameters, the current parameter will be displayed for
two seconds. After two seconds, the display will show
the data for the current parameter. When the last
parameter is reached, the list will wrap back to P1.
the display will show “------”. If the auto key is held down
for five seconds while “------” is displayed all inactive
alarms are cleared. A listing of alarm codes is provided
in Table 3-2.
3.2.2 Activation
3.2 SYSTEM ALARMS
When alarms are detected, they are placed in an alarm
queue in the order at which they initiated unless the
alarm is already present. Each alarm recorded will also
capture an evaporator hour meter reading corresponding
to the activation time. If the AUTO key is pressed while
an alarm is displayed, the activation time capture will be
shown.
3.2.1 Alarm Codes
3.2.3 Alarm Queue
The Micromax Logic Board continuously monitors
system parameters and will generate an ALARM if a
parameter exceeds preset limits. Alarms are indicated
and the controller will respond in accordance with the
information provided in Table 3-2. The alarm codes can
be read by counting the number of times that the Logic
Board CODE LED (see Figure 1-10) flashes. Flashing
lights indicate active alarms. Each alarm code is a two
digit number, the first set of flashes is the first digit and
(after a slight pause) the second set of flashes is the
second digit. The Micromate display will indicate
alarms with the code A-## or i--##, where “A” is an
active alarm prefix, “i” is an inactive alarm prefix and ##
is the error number. If multiple alarms are present the
user can scroll through each alarm by pressing the
ARROW keys. When the end of the alarm list is reached
The alarm queue can hold 10 alarms. When the alarm
queue is full the Logic Board will take the required
action but the alarm will not be recorded. When this
situation occurs, an “Alarm Queue Full”alarm will be
generated. When the alarms are viewed this will be the
first alarm to be shown.
3.2.4 Alarm Clear
The user may clear inactive alarms using the Micromate
keypad. Refer to paragraph 3.2.1.
3.3
MICROPROCESSOR DIAGNOSTICS
The Micromate allows the user to interface with the
microprocessor based control. This allows system
parameters, alarms and settings to be viewed and
modified.
3-1
T-310
The Micromate (Figure 1-8) will allow the user to
interface with the microprocessor based control from
the driver’s control panel. The Micromate Display
Panel (Figure 1-7) requires that the Micromate
Diagnostic Service Tool (P/N 76-62124-01) will need
to be used to access the system. The service tool plugs in
to the Logic Module to Driver Display Harness located
on the electrical control panel (Figure 1-11).
Table 3-2 Alarm Codes
ALARM
NO.
TITLE
CAUSE
REMEDY
CONTROLLER
RESPONSE
A12
High Voltage
The battery voltage is
greater than 32 volts.
Check, repair or replace alternator.
The system is shut down
until the voltage returns
to normal levels.
A13
Low Voltage
The battery voltage is
less than 17 volts.
Check, repair or replace wiring or alternator.
The system is shut down
until the voltage returns
to normal levels.
A14
Return Air Probe Failure
Return air temperature Ensure all connectors
sensor failure or wir- are plugged in. Check
ing defective.
sensor resistance or
wiring. Refer to paragraph 4.13. Replace
sensor or repair wiring.
A15
Suction Pressure
Transducer Failure
Suction pressure
transducer failure or
wiring defective.
Ensure all connectors Both unloaders are enerare plugged in. Check gized.
sensor voltage or wiring. Replace sensor or
repair wiring.
A16
Discharge Pressure
Transducer Failure
Discharge pressure
transducer failure or
wiring defective.
Ensure all connectors One unloader is enerare plugged in. Check gized.
sensor voltage or wiring. Replace sensor or
repair wiring.
A17
Low Pressure Shutdown
Low suction pressure
(below 10 psig)
Check cause of low
suction pressure. (Refer to section 3.4.3)
The clutch is de-energized for the minimum
off time. The evaporator
fans will remain running
during this period. After
the compressor cycles
off three times in 30
minutes all outputs will
be de-energized and the
system is locked out until the power is cycled or
the alarm is reset.
A21
High Discharge Pressure
High discharge pressure switch open or
wiring defective.
Check discharge pressure transducer reading, wiring or cause of
high discharge pressure. (Refer to section
3.4.3)
The clutch is de-energized for the minimum
off time. The condenser
and evaporator fans will
remain running during
this period. After the
compressor cycles off
three times in 30 minutes all outputs will be
de-energized and the
system is locked out until the power is cycled or
the alarm is reset.
T--310
3-2
All outputs except the
evaporator fans will be
de-energized.
Table 3-2. Alarm Codes -- Continued
ALARM
NO
TITLE
CAUSE
REMEDY
CONTROLLER
RESPONSE
A22
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 breaker.
A23
Evaporator Fan Overload Evaporator fan overload jumper is open.
Ensure connector is
plugged in or repair
wiring.
Alarm will be generated.
A24
Condenser Fan Overload
Condenser fan overload jumper is open.
Ensure connector is
plugged in or repair
wiring.
Alarm will be generated.
A25
Motor Failure
A brushless motor has Replace motor
not reached full operating speed or a motor
failure.
A26
Not used
A31
Maintenance Alarm 1
The compressor hour
meter is greater than
the value in Maintenance Hour Meter 1.
Reset the maintenance Alarm will be generated.
hour meter.
A32
Maintenance Alarm 2
The evaporator hour
meter is greater than
the value in Maintenance Hour Meter 2.
Reset the maintenance Alarm will be generated.
hour meter.
A99
Alarm Queue Full
All locations of the
alarm queue are currently full and no
more alarms can be
saved.
Record and clear
alarm queue.
3.3.1 Control
Alarm displayed and the
motor fail output is energized.
Alarm will be generated.
3.3.2 Diagnostic Mode
Diagnostic mode can be entered by pressing the up and
down arrow keys simultaneously for 5 seconds.
Diagnostic mode allows alarms and system parameters
to be viewed. If there are any alarms stored, the most
recent alarm will be shown. To view additional alarm
information, refer to section 3. Press the up and down
arrow keys to view parameters.
NOTE
1
This procedure should be performed by an
HVAC technician who has been trained on
Carrier system design. Control configuration is
preset by the manufacturer.
2
If a replacement Logic Module is installed, it is
necessary to match the configuration jumpers
(see Figure 1-10) to the original board. Refer to
paragraph 4.24.
3.3.3 Test Mode
With the system in normal operation, the controller may
be placed in the test mode, by doing the following:
a. Enter the diagnostic mode by pressing the up and
down arrow keys simultaneously for 5 seconds. Enter
the test mode by pressing the COOL key five times.
b. In the test mode, the display will read “T##” where
“##” indicated the test number that is currently running.
c. The initial indication will be “T00”. This indicates
the controller is in the test mode and all relays are de-energized. Press the arrow keys to scroll through and
perform each test When the highest test number is
reached, the display will increment back to the lowest
test number. A listing of tests is provided in
Table 3-3.
d. To terminate testing, press the I/0 key.
a. Turn the A/C main power switch (located in the driver’s area) to OFF.
b. Turn the A/C main power switch back to the ON position.
c. Activate the system by pressing the 1/0 key on the
Micromate panel.
NOTE
When modifying the setpoint temperature for
diagnostic purposes, be sure to reset the setpoint when testing is complete.
3-3
T-310
Table 3-3. Controller Test List
OUTPUT
STATE
TEST
T00
T01
T02
T03
T04
T05
All Relays
Evaporator High
Evaporator Low
Condenser High
Condenser Low
Compressor & Liquid
Line Solenoid
T06
T07
T08
T09
T10
T11
T12
Off
On
On
On
On
On
Unloader Valve 1
Unloader Valve 2
Not Applicable
Reheat Coolant Valve
Fault
Boost
Spare/Motor Input/
On
On
On
On
On
On
On
Table 3-4. Parameter Codes
CODE
CODE NAME
DESCRIPTION
P1
Return Air
Temperature
This value is the temperature measured by the return air sensor. If the sensor is
shorted it will display CL. If it is open circuited it will display OP.
P2
Coil Temperature
Not used.
P3
Ambient Temperature
This value is the outside temperature measured by the ambient temperature
sensor. If the sensor is shorted it will display CL. If it is open circuited it will
display OP.
P4
Suction Line
Temperature
This value is the temperature of the refrigerant gas leaving the evaporator coil.
If the sensor is shorted it will display CL. If it is open circuited it will display
OP.
P5
Suction Pressure
This value is the suction pressure measured by the suction pressure transducer.
If the sensor is shorted it will display CL If it is open circuited it will display
OP.
P6
Discharge Pressure
This value is the discharge pressure measured by the discharge pressure transducer. If the sensor is shorted it will display “CL” and if it is open circuited it
will display “OP”.
P7
Superheat
This value is calculated by the Micro Max using values P4 and P5.
P8
Analog Set Point
Temperature
Not used.
P9
A/C Control Window
#1
This is the number of degrees F above setpoint at which the unloaders will be
both energized. This value can be modified between 0 and 10 degrees F. The
default value is 2 degrees F.
P10
A/C Control Window
#2
This is the number of degrees F above AC control window one at which the
first unloader will be energized. This value can be modified between 0 and 10
degrees F. The default value is 2 degree F.
P11
A/C Control Window
#3
This is the number of degrees F above AC control window two at which the
evaporator fan speed will be set to low. This value can be modified between 0
and 10 degrees F. The default value is 1 degree F.
P12
Heat Control Window This is the number of degrees F below setpoint before the EHV is energized.
This value can be modified between 0 and 10 degrees F. The default value is 2
degree F for heat and 4 degrees F for reheat.
P13
Compressor Safety
Off Delay
This number is the minimum time in minutes that the compressor must be off
after a high or low pressure alarm before it can be restarted. This value can be
modified between one and five minutes. The default value is 1.
P14
Fan Delay
This is the minimum time (in seconds) that the fans must run at a particular
speed before changing to another speed. This value can be modified between
one and 60 seconds. The default value is two seconds.
T--310
3-4
Table 3-4. Parameter Codes -- Continued
CODE
CODE NAME
DESCRIPTION
P15
Reheat Valve Delay
This is the minimum time (in seconds) that the reheat valve must be in a particular state (open /closed) before changing to another state. This value can be
modified between 1 and 60 seconds. The default value is 2 seconds.
P16
Compressor High
Pressure Switch
This is the current state of the compressor high pressure switch input. “CL”
will be displayed if it is closed and “OP” will be displayed if it is open.
P17
Condenser Fan Speed
Switch
Not used.
P18
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. The system default is 80F.
P19
Minimum Setpoint
This is the minimum 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. The system default is 60F.
P20
Compressor Hours
High
This is the number of hours of operation that the compressor has run with the
clutch energized in thousands
P21
Compressor Hours
Low
This is the number of hours of operation that the compressor has run with the
clutch energized in hundreds, tens and ones.
P22
Evaporator Hours
High
This is the number (in thousands) of hours of operation with the evaporator
fans energized.
P23
Evaporator Hours
Low
This is the number (in hundreds, tens and ones) of hours of operation with the
evaporator fans energized.
P24
Maintenance 1 Hour
High
This is the value of compressor hours high (P20) at which maintenance alarm
#1 will be activated. This value can be modified by the up and down arrow
keys. If both high and low values are zero the alarm is disabled.
P25
Maintenance 1 Hour
Low
This is the value of compressor hours low (P21) at which maintenance alarm
#1 will be activated. This value can be modified by the up and down arrow
keys. If both high and low values are zero the alarm is disabled.
P26
Maintenance 2 Hours
High
This is the value of evaporator fan hours high (P22) at which maintenance
alarm #2 will be activated. This value can be modified by the up and down
arrow keys. If both high and low values are zero the alarm is disabled.
P27
Maintenance 2 Hours
Low
This is the value of evaporator fan hours low (P23) at which maintenance
alarm #2 will be activated. This value can be modified by the up and down
arrow keys. If both high and low values are zero the alarm is disabled.
P28
Freeze Alarm Setting
Not used.
P29
Relay Module Voltage This is the voltage being supplied to the relay module.
P30
Main Board Software
Version
This is the software version of the logic board.
P31
Display Software
Version
This is the software version of the display module.
P32
Ki
Not used.
P33
Kp
Not used.
P34
Default Display
This is the value displayed on the Micromate control panel. It is set to OFF to
display set point temperature or set to ON to display return air temperature.
This feature is available in software revision 1.9 and later.
3-5
T-310
3.4 TROUBLESHOOTING
General procedures for system troubleshooting are provided in Table 3-5
Table 3-5. General System Troubleshooting Procedures
INDICATION/
TROUBLE
3.4.1 System Will Not Cool
Compressor will not run
Electrical malfunction
POSSIBLE CAUSES
Active system alarm
V-Belt loose or defective
Clutch coil defective
Clutch malfunction
Compressor malfunction
Coach power source defective
Circuit Breaker/safety device open
REFERENCE
SECTION
3.2
Check
Check/Replace
Check/Replace
See Table 1-2
Check/Repair
Check/Reset
3.4.2 System Runs But Has Insufficient Cooling
Compressor
Refrigeration system
Restricted air flow
Heating system
V-Belt loose or defective
Compressor valves defective
Abnormal pressures
No or restricted evaporator air flow
Expansion valve malfunction
Restricted refrigerant flow
Low refrigerant charge
Service valves partially closed
Safety device open
Liquid solenoid valve stuck closed
No evaporator air flow or restriction
Reheat coolant valve stuck open
Check
See Table 1-2
3.4.3
3.4.6
3.4.7
4.10
4.7
Open
1.7
Check
3.4.6
3.4.8
Discharge transducer failure
Refrigerant overcharge
Noncondensable in system
Condenser motor failure
Condenser coil dirty
Discharge transducer failure
Compressor valve(s) worn or broken
Low refrigerant charge
Compressor valve(s) worn or broken
Suction service valve partially closed
Filter-drier inlet valve partially closed
Filter-drier partially plugged
Low refrigerant charge
Expansion valve malfunction
Restricted air flow
Suction transducer failure
Compressor valve defective
Replace
4.7.1
Check
Check
Clean
See Note.
See Table 1-2
4.7
See Table 1-2
Open
Check/Open
4.10
4.7
3.4.7
3.4.6
Replace
See Table 1-2
3.4.3 Abnormal Pressures
High discharge pressure
Low discharge pressure
High suction pressure
Low suction pressure
Suction and discharge pressures
tend to equalize when system is
operating
3.4.4 Abnormal Noise Or Vibrations
Compressor
T--310
Loose mounting hardware
Worn bearings
Worn or broken valves
Liquid slugging
Insufficient oil
Clutch loose, rubbing or is defective
V-belt cracked, worn or loose
Dirt or debris on fan blades
3-6
Check/Tighten
See Table 1-2
See Table 1-2
3.4.7
4.12.2
Check
Check/Adjust
Clean
Table 3-5 General System Troubleshooting Procedures -- Continued
INDICATION/
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
3.4.4 Abnormal Noise Or Vibrations -- Continued
Condenser or evaporator fans
Loose mounting hardware
Defective bearings
Blade interference
Blade missing or broken
Check/Tighten
Replace
Check
Check/Replace
3.4.5 Control System Malfunction
Will not control
Sensor or transducer defective
Relay(s) defective
Microprocessor controller malfunction
Logic Board J3 connector unplugged
4.13 or 4.14
Check
Check
Check
3.4.6 No Evaporator Air Flow Or Restricted Air Flow
Air flow through coil blocked
No or partial evaporator air flow
Coil frosted over
Dirty coil
Dirty filter
Motor defective
Motor brushes defective
Evaporator fan loose or defective
Fan damaged
Return air filter dirty
Icing of coil
Fan relay defective
Safety device open
Fan rotation incorrect
Defrost coil
Clean
Clean/Replace
Repair/Replace
Replace
Repair/Replace
Repair/Replace
Clean/Replace
Clean/Defrost
Check/Replace
1.7
Check
3.4.7 Expansion Valve Malfunction
Low suction pressure with high
superheat
Low superheat and liquid slugging in the compressor
Side to side temperature difference (Warm Coil)
Low refrigerant charge
Wax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary tube
Bulb is loose or not installed.
Superheat setting too low
Ice or other foreign material holding valve open
Wax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary
4.7
Check
4.6
Replace
Replace
4.11
4.11
4.11
Check
4.6
Replace
Replace
4.11
3.4.8 Heating Malfunction
Insufficient heating
No Heating
Continuous Heating
Dirty or plugged heater core
Reheat coolant solenoid valve(s) malfunctioning or
plugged
Low coolant level
Hand valve(s) closed
Water pumps defective
Auxiliary Heater malfunctioning.(if equipped)
Reheat coolant solenoid valve(s) malfunctioning or
plugged
Controller malfunction
Pump malfunctioning
Safety device open
Reheat coolant solenoid valve stuck open
3-7
Clean
Check/Replace
Check
Open
Repair/Replace
Repair/Replace
Check/Replace
Replace
Repair/Replace
1.8
Replace
T-310
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
WARNING
READ THE ENTIRE PROCEDURE BEFORE BEGINNING WORK. PARK THE COACH ON A
LEVEL SURFACE, WITH PARKING BRAKE APPLIED. TURN MAIN ELECTRICAL
DISCONNECT SWITCH TO THE OFF POSITION.
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. Refer to paragraph 3.2.4.
4.1 MAINTENANCE SCHEDULE
SYSTEM
ON
REFERENCE
paragraph
OPERATION
OFF
a. Daily Maintenance
X
X
Pre-trip Inspection -- after starting
Check tension and condition of V-belt
2.2
None
b. Weekly Inspection
X
X
X
X
Perform daily inspection
Check condenser, evaporator coils and air filters for cleanliness
Check refrigerant hoses and compressor shaft seal for leaks
Feel filter-drier for excessive temperature drop across drier
4.1.a
None
4.5
4.10.1
c. Monthly Inspection and Maintenance
X
X
X
X
X
X
Perform weekly inspection and maintenance
Clean evaporator drain pans and hoses
Check wire harnesses for chafing and loose terminals
Check fan motor bearings
Check compressor mounting bolts for tightness
Check fan motor brushes
4.2 SUCTION AND DISCHARGE SERVICE
VALVES
4.1.b
None
Replace/Tighten
None
None
4.18, 4.22
to allow full flow through the valve. The valve should
always be backseated when connecting the service
manifold gauge lines to the gauge ports.
Turning the valve stem clockwise (all the way forward)
will frontseat the valve to close off the suction or
discharge line to isolate the compressor and open the
gauge connection.
To measure suction or discharge pressure, midseat the
valve by opening the valve clockwise 1/4 to 1/2 turn.
With the valve stem midway between frontseated and
backseated positions, the suction or discharge line is
open to both the compressor and the gauge connection.
The suction and discharge service valves (See
Figure 4-1) used on the compressor are equipped with
mating flanges for connection to flanges on the
compressor. These valves are provided with a double
seat and a gauge connection, which allows servicing of
the compressor and refrigerant lines.
Turning the valve stem counterclockwise (all the way
out) will backseat the valve to open the suction or
discharge line to the compressor and close off the gauge
connection. In normal operation, the valve is backseated
4-1
T-310
Valve Cap
To Discharge or
from Suction Line
Gauge
Connection
Port to
Compressor
Service Valve
Frontseated
(clockwise)
b. Connect the high side hose tightly to discharge
service valve port.
c. Connect the low side hose loosely to suction service
valve port.
d. Loosen charging (center) hose at dummy fitting of
manifold set.
e. Frontseat (clockwise) both manifold gauge hand
valves.
f. Open discharge service valve counterclockwise
approximately 1/4 to 1/2 turn.
g. Slowly open (counterclockwise) manifold discharge
hand valve approximately one turn.
h. Tighten charging hose onto dummy fitting.
i. Slowly open the manifold suction hand valve to
remove air from line.
j. Tighten suction hose at the suction service valve port.
k. Frontseat (close) both manifold hand valves.
l. Open suction service valve counterclockwise
approximately 1/4 to 1/2 turn.
Valve
Stem
Service Valve
Backseated
(counterclockwise)
Figure 4-1. Suction or Discharge Service Valve
4.3 INSTALLING MANIFOLD GAUGES
4.4 PUMPING THE SYSTEM DOWN OR
REMOVING THE REFRIGERANT CHARGE
The manifold gauge (Figure 4-2) set can be used to
determine system operating pressures, add charge,
equalize or evacuate the system.
Low Pressure
Gauge
NOTE
To avoid damage to the earth’s ozone layer, use
a refrigerant recovery system whenever
removing refrigerant.
High Pressure
Gauge
4.4.1 System Pumpdown
Hand Valve
(Open)
A
C
B
To service or replace the filter-drier, expansion valve,
evaporator coil, or suction line, pump the refrigerant
into condenser coil and receiver as follows:
a. Install manifold gauge set. (Refer to paragraph 4.3.)
b. Unplug the suction pressure transducer(SPT).
Hand Valve
(Frontseated)
A. Connection to
C. Connection to Either:
Low Side of System Vacuum Pump Refrigerant
Cylinder Oil Container
B. Connection to
Evacuation Line
High Side of System
NOTE
The following procedure may have to be
repeated several times to maintain the 1 psig
(6.9 kPa) pressure depending upon amount of
refrigerant absorbed in the oil.
Figure 4-2. Manifold Gauge Set
c. Frontseat filter-drier inlet service valve by turning
clockwise. Shut off the parcel evaporator liquid line
shut off valve. Start system and run in cooling. Stop
the unit when the suction pressure reaches a slight
vacum (1--2”/hg). Allow pressure to stabilize to 2
psig (13.8 kPa) to maintain a slight positive pressure.
d. Frontseat (close) suction service valve to trap the
refrigerant in the high side of the system between the
compressor suction service valve and the filter drier
inlet valve. The low side of the system will now be at
2 psig (13.8 kPa) pressure and ready for servicing,
e. Service or replace the necessary component on the
low side of the system.
f. Leak check connections. (Refer to paragraph 4.5.)
The manifold gauge set (Figure 4-2) is equipped with
hand valves, gauges and refrigerant openings. When the
low pressure hand valve is frontseated (turned all the
way in), the low (evaporator) pressure can be checked.
When the high pressure hand valve is frontseated, high
(condensing) pressure can be checked. When both
valves are open (turned counterclockwise), high
pressure vapor will flow into the low side. When the low
pressure valve is open, the system can be charged or
evacuated. Oil can also be added to the system.
Install the manifold gauge set as follows:
a. Remove both service valve stems and service port
caps. Backseat (counterclockwise) both service
valves.
T-310
4-2
d. Start the unit and run in cooling until a slight vacuum
(1--2”) is reached. Shut the system down and tag out
system power source.
g. Evacuate and dehydrate the low side. (Refer to
paragraph 4.6.)
h. Reconnect the suction pressure transducer(SPT).
e. Frontseat the compressor discharge service valve and
wait 5 minutes to verify vacuum is maintained. If the
pressure rises above vacuum, open the compressor
discharge service valve and repeat steps c. and d .until
a vacuum is maintained.
4.4.2 Removing the Refrigerant Charge
Connect a refrigerant recovery system to the unit near
the receiver to remove refrigerant charge. (Refer to
Figure 4-4.) Refer to instructions provided by the
manufacturer of the refrigerant recovery system.
f. Service or replace components as required and leak
check the entire system.
NOTES
g. Using refrigerant hoses designed for vacuum service,
connect a vacuum pump to center connection of
manifold gauge set. Evacuate system to to below 500
microns. Close off pump valve, isolate vacuum gauge
and stop pump. Wait 5 minutes to verify that vacuum
holds at or below 500 microns.
1. Before opening up any part of the system, a
slight positive pressure should be indicated
on the gauge.
2. When opening up the refrigerant system,
certain parts may frost. Allow the part to
warm to ambient temperature before
dismantling;
this
avoids
internal
condensation, which puts moisture into the
system.
h. Once vacuum is maintained, backseat compressor
service valves and disconnect manifold gauge set.
i. Reconnect the suction pressure transducer(SPT).
3
4.4.3 Refrigerant Removal From An Inoperative
Compressor.
S D
2
To remove the refrigerant from a compressor that is not
operational, do the following:
1
a. Attach a manifold gauge set as shown in Figure 4-3
and isolate the compressor by frontseating the suction
and discharge valves.
4
b. Recover refrigerant with a refrigerant reclaimer. If the
discharge service valve port is not accessible, it will
be necessary to recover refrigerant through the
suction service valve port only.
c. Service or replace components as required and leak
check the entire system.
5
7
6
d. Using refrigerant hoses designed for vacuum service,
connect a vacuum pump to center connection of
manifold gauge set. Evacuate system to or below 500
microns. Close off pump valve, isolate vacuum gauge
and stop pump. Wait 5 minutes to verify that vacuum
holds at or below 500 microns.
1. Discharge Service
Valve and Port
2. Suction Service
Valve and Port
3. Manifold Gauge
Set
e. Once vacuum is maintained, recharge high side with
R-134a to proper charge. Backseat compressor
service valves and disconnect manifold gauge set.
4.4.4 Pump Down An Operable Compressor For
Repair
4. Vacuum Pump
5. Recycle/Recovery
Machine
6. Refrigerant Cylinder
7. Thermistor Vacuum
Gauge
Figure 4-3. Compressor Service Connections
To service an operable compressor, pump the refrigerant
into the condenser coil and receiver as follows:
4.5 REFRIGERANT LEAK CHECK
a. Install manifold gauge set. Refer to Figure 4-3.
b. Unplug the suction pressure transducer(SPT).
A refrigerant leak check should always be performed
after the system has been opened to replace or repair a
component.
c. Frontseat the compressor suction service valve by
turning clockwise.
To check for leaks in the refrigeration system, perform
the following procedure:
4-3
T-310
NOTE
It must be emphasized that only the correct
refrigerant drum should be connected to
pressurize the system. Any other gas or vapor
will contaminate the system, which will require
additional evacuation and evacuation of the
high (discharge) side of the system.
a. Evacuate and dehydrate only after a refrigerant leak
check. (Refer to paragraph 4.5.)
a. Ensure the main liquid line and driver solenoid valves
are open.
b. If system is without refrigerant, charge system with
refrigerant to build up pressure between 30 to 50 psig
(207 to 345 kPa).
c. Keep the ambient temperature above 60_F (15.6_C)
to speed evaporation of moisture. If ambient
temperature is lower than 60_F (15.6_C), ice may
form before moisture removal is complete. It may be
necessary to use heater blankets, heat lamps or
alternate sources of heat to raise system temperature.
c. Add sufficient nitrogen to raise system pressure to
150 to 200 psig (1.03 to 1.4 mPa).
4.6.3 Procedure for Evacuation and Dehydrating
System
b. Essential tools to properly evacuate and dehydrate
any system include a good vacuum pump with a
minimum of 6 cfm (10.2 m 3/hr) volume
displacement (CTD P/N 07-00176-11), and a good
vacuum indicator (CTD P/N 07-00414-00).
d. Check for leaks. The recommended procedure for
finding leaks in a system is with an electronic leak
detector. Testing joints with soapsuds is satisfactory
and may be necessary under conditions when an
electronic leak detector will not function correctly.
a. Remove refrigerant using a refrigerant recovery
system.
b. Evacuation should be performed through three ports
in the refrigeration system. The hoses should be
connected to the compressor suction and discharge
service ports, and to the liquid line shut off
valve.(Figure 4-4)
e. Remove refrigerant from system and repair any leaks.
f. Evacuate and dehydrate the system. (Refer to
paragraph 4.6.)
c. Connect lines to unit and manifold and make sure
vacuum gauge valve is closed and vacuum pump
valve is open.
g. Charge the unit. (Refer to paragraph 4.7.)
h. Ensure that self-test has been performed and that
there are no errors or alarms indicated. (Refer to
paragraph 2.1.4)
d. Open solenoid valves electrically to ensure a good
vacuum is obtained.
4.6 EVACUATION AND DEHYDRATION
e..Start vacuum pump. Slowly open valves halfway and
then open vacuum gauge valve.
4.6.1 General
The presence of moisture in a refrigeration system can
have many undesirable effects. The most common are
copper plating, acid sludge formation, “freezing-up” of
metering devices by free water, and formation of acids,
resulting in metal corrosion.
f.. Evacuate unit until vacuum gauge indicates 500
microns (29.90 inches = 75.9 cm Hg vacuum). Close
gauge valve, vacuum pump valve, and stop vacuum
pump.
4.6.2 Preparation
g. Break the vacuum with clean dry refrigerant. Use
refrigerant that the unit calls for. Raise system
pressure to approximately 2 psig (13.8 kPa).
NOTE
Using a compound gauge for determination of
vacum level is not recommended because of its
inherent inaccuracy, a calibrated vacuum gage
is recommended.
h. Remove refrigerant using a refrigerant recovery
system.
i. Repeat steps e, f, g, and h one time.
j. Start vacuum pump and open all valves. Dehydrate
unit to 500 microns (29.90 inches = 75.9 cm Hg
vacuum).
NOTE
Using six foot long charging hoses will
simplify the evacuation/charging procedures
that follow.
k. Close off pump valve, isolate vacuum gauge in
system and stop pump. Wait five minutes to see if
vacuum holds.
l. With a vacuum still in the unit, the refrigerant charge
may be drawn into the system from a refrigerant
container on weight scales.
NOTE
Never evacuate a refrigerant system with an
open drive compressor below 500 microns.
T-310
4-4
DRIVER SOLENOID VALVE
(N/C)
TXV
BULB
TXV
DRIVER EVAP. MODULE
1. Recovery/Recycle Machine
2. Manifold Guage Set
3. Thermistor Vacuum gauge
4. Vacuum Pump
5. Refrigerant Cylinder
6. Suction Service Valve
and Service Port
7. Discharge service Valve
and Service Port
PASSENGER EVAP. MODULE
TXV
BULB
TXV
PRESSURE
TAP
MAIN LIQUID LINE
SOLENOID VALVE
(N/C)
PARCEL LIQUID LINE
SOLENOID VALVE
(N/C)
TXV
FILTER DRIER
PARCEL
EVAP.
MODULE
PARCEL EVAP.
LIQUID LINE
SHUT OFF VALVE
(N/C)
TXV
LIQUID LINE
SERVICE VALVE
PARCEL
EVAP.
MODULE
FUSIBLE
PLUG
S D
1
RECEIVER
2
3
DISCHARGE
LINE SERVICE
VALVE
5
DISCHARGE
CHECK VALVE
4
7
6
CONDENSER MODULE
4
COMPRESSOR
Figure 4-4. Refrigerant Service Connections
4-5
T-310
4.7 ADDING REFRIGERANT TO SYSTEM
NOTE
The following conditions must be met to
accurately check the refrigerant level:
4.7.1 Checking Refrigerant Charge
The following conditions must be met to accurately
check the refrigerant charge.
1. Coach engine must be operating at high
idle speed.
a. Coach engine operating at high idle.
b. Unit operating in cool mode for at least 15 minutes.
c. Discharge pressure at least 150 psig (1.03 mPa) for
R-134a systems. (It may be necessary to block
condenser air flow to raise discharge pressure.)
2. Unit must be operating in the cool mode for
at least 15 minutes.
Under the above conditions, the system is properly
charged when the bottom receiver sight glass appears
half full with refrigerant. If the bottom sight glass is not
half full, add or remove refrigerant charge to the proper
level.
3. Discharge pressure must be at least 150
psig (1.0 mPa). (It may be necessary to
block condenser airflow to raise discharge
pressure.)
4.7.2 Adding Full Charge
c. Run unit in cool mode for 15 minutes. With suction
service valve midseated, remove air from hose at
refrigerant cylinder. Open cylinder valve and add
vapor charge until refrigerant level appears in the
lower receiver sight glass. Under the above
conditions, the system will be properly charged when
the lower receiver sight glass appears full of
refrigerant. Add or remove refrigerant until the
proper level is obtained. Refrigerant level should not
appear in the upper sight glass, as this would
indicate an overcharge.
a. Evacuate and dehydrate system. (Refer to paragraph
4.6.)
b. Place appropriate refrigerant cylinder on scales and
connect charging hose from container to filter-drier
inlet valve. Remove air from hoses.
c. Note weight of refrigerant and container.
d. Open liquid valve on refrigerant container. Midseat
filter-drier inlet valve and allow refrigerant to flow
into the unit. Refer to paragraph 1.4 for correct
charge.
d. Backseat suction service valve. Close vapor valve on
refrigerant drum and note weight. Replace all valve
caps.
e. When drum weight (scale) indicates that the correct
charge has been added, close liquid line valve on
drum and backseat the filter-drier inlet valve.
NOTES
The following conditions must be met to
accurately check the refrigerant level:
4.8 CHECKING FOR NONCONDENSIBLES
1. Coach engine must be operating at high
idle speed.
a. Stabilize system to equalize pressure between the
suction and discharge side of the system.
2. Unit must be operating in the cool mode for
at least 15 minutes.
b. Check temperature at the condenser and receiver.
To check for noncondensibles, proceed as follows:
c. Check pressure at the compressor discharge service
valve.
3. Discharge pressure must be at least 150
psig (1.0 mPa). (It may be necessary to
block condenser airflow to raise discharge
pressure.)
d. Check saturation pressure as it corresponds to the
condenser/receiver
temperature
using
the
Temperature-Pressure Chart, Table 4-5.
e. If gauge reading is 3 psig (21 kPa) or more than the
calculated P/T pressure in step d., noncondensibles
are present.
f. Under the above conditions, the system is properly
charged when the refrigerant liquid level is visible in
the receiver lower sight glass. If it is not visible, add
or remove refrigerant until it is at the proper level.
f. Remove refrigerant using a refrigerant recovery
system.
4.7.3 Adding Partial Charge
a. Start the vehicle engine and allow unit to stabilize.
g. Evacuate and dehydrate the system. (Refer to
paragraph 4.6.)
b. Place appropriate refrigerant cylinder on scales and
connect charging hose from container vapor valve to
compressor suction service valve.
T-310
h. Charge the unit. (Refer to paragraph 4.7.)
4-6
4.9 CHECKING AND REPLACING HIGH
PRESSURE CUTOUT SWITCH
4.10 FILTER-DRIER
4.10.1 To Check Filter Drier
4.9.1 Checking High Pressure Switch
Check for a restricted or plugged filter-drier by feeling
the liquid line inlet and outlet connections of the
filter-drier. If the outlet side feels cooler than the inlet
side, then the filter-drier should be changed.
WARNING
DO NOT USE A NITROGEN CYLINDER
WITHOUT A PRESSURE REGULATOR
4.10.2 To Replace Filter Drier
DO NOT USE OXYGEN IN OR NEAR A
REFRIGERATION SYSTEM AS AN
EXPLOSION MAY OCCUR.
a. Install a manifold gauge set to the liquid line shut off
valve. (Refer to paragraph 4.3.)
b. Start the system.
c. Front seat the liquid line service valve.(See
Figure 4-4.)
d. Shut the system down when the indicated pressure
reaches 1 psig. The liquid line solenoid valve will
close when the system shuts down, sealing the filter
drier from the rest of the system.
e. Replace the filter drier, ensuring that the arrow points
in the direction of the refrigerant flow.
f. Drier can be evacuated at liquid line service valve.
(See Figure 4-4.)
g. Check refrigerant level. (Refer to paragraph 4.7.1.)
a. Remove switch from unit. All units are equipped with
schrader valves at the high pressure switch
connection.
b. Connect an ohmmeter across switch terminals. If the
switch is good, the ohmmeter will indicate no
resistance, indicating that the contacts are closed.
c. Connect switch to a cylinder of dry nitrogen. (See
Figure 4-5.).
1
4
2
3
5
6
1. Cylinder Valve
and Gauge
2. Pressure Regulator
3. Nitrogen Cylinder
4. Pressure Gauge,
0 to 400 psig
(0 to 2.8 mPa)
5. Bleed-Off Valve
6. 1/4 inch Connection
4.11 THERMOSTATIC EXPANSION VALVE
The thermostatic expansion valve (TXV) is an
automatic device which maintains constant superheat of
the refrigerant gas leaving the evaporator regardless of
suction pressure. The valve functions are: (a) automatic
response of refrigerant flow to match the evaporator
load and (b) prevention of liquid refrigerant returning to
the compressor. Unless the valve is defective, it seldom
requires any maintenance.
Figure 4-5. Checking High Pressure Switch
d. Set nitrogen pressure regulator higher than cutout
point on switch being tested. (See paragraph 1.4.)
e. Open cylinder valve. Slowly open the regulator valve
to increase the pressure until it reaches cutout point.
The switch should open, which is indicated by an
infinity reading on an ohmmeter (no continuity).
1
2
3
f. Close cylinder valve and release pressure through the
bleed-off valve. As pressure drops to cut-in point, the
switch contacts should close, indicating no resistance
on the ohmmeter.
5
4
g. Replace switch if it does not function as outlined
above. (Refer to paragraph 4.9.2.)
4.9.2 Replacing High Pressure Switch
1.
2.
3.
4.
5.
a. The high pressure switch is equipped with schrader
valve to allow removal and installation without
pumping the unit down.
c. Disconnect wiring from defective switch.
d. Install new cutout switch.
e. Check switch operation. (Refer to paragraph 4.9.1.)
Bulb
Power Head Assembly
Equalizer Connection
Outlet Connection
Inlet Connection
Figure 4-6. Thermostatic Expansion Valve
4-7
T-310
4.11.1 Replacing the Power Head/Bulb Assembly
(See Figure 4-6.)
b. Remove insulation (Presstite) from expansion valve
bulb.
In the event that the power head and/or the bulb and
capillary tube loses its charge due to physical damage,
it(powerhead/cap tube/bulb assembly) can be replaced.
a. Pump down low side of the unit. (Refer to paragraph
4.4.)
b. Remove insulation (Presstite) from expansion valve
bulb.
c. Loosen retaining straps holding bulb to suction line
and detach bulb from the suction line.
d. Carefully, with two wrenches, one one the power
head and the other on the valve body, loosen the
power head assembly and remove from valve body.
e. Check for debris in valve and clean if necessary.
f. Carefully install the new power head/cap tube/bulb
assembly, paying particular caution to the cap
tube/bulb as the head is rotated on to the valve body.
g. The thermal bulb is installed below the center of the
suction line (four or eight o’clock position). This area
must be clean to ensure positive bulb contact. Clean
the suction line with sandpaper or emery cloth before
installing bulb to ensure proper heat transfer. Strap
thermal bulb to suction line and insulate both with
“Presstite.” Ensure that retaining straps are tight. (See
Figure 4-8.)
h. Evacuate and dehydrate. (Refer to paragraph 4.6.)
i. Open filter-drier inlet valve (liquid line service valve)
and all service valves.
j.Run the coach for approximately 30 minutes on fast
idle.
k.Check refrigerant level. (Refer to paragraph 4.7.1.)
l.Check superheat. (Refer to paragraph 4.11.3.)
c. Loosen retaining straps holding bulb to suction line
and detach bulb from the suction line.
4.11.2 Replacing the
Figure 4-6.)
Expansion
Valve
NOTE
Always purge the refrigerant system with an
inert gas such as nitrogen before proceeding
with any brazing operation.
d. Unbraze the copper straps that secure the refrigerant
line on each side of the TXV to the coil.
e. Disconnect the liquid line at the bulkhead connection
and at the parcel rack connection.
f. Unbraze the equalizer connection, the outlet
connection, then the inlet connection. Be careful to
protect any insulation and wiring that are in the area.
g. Braze inlet connection to the liquid line.
h. Braze outlet connection to the evaporator.
i. Braze equalizer line to the equalizer connection.
j. The thermal bulb is installed below the center of the
suction line (four or eight o’clock position). This area
must be clean to ensure positive bulb contact. Clean
the suction line with sandpaper or emery cloth before
installing bulb to ensure proper heat transfer. Apply
thermal grease to the indentation in the suction line.
Strap thermal bulb to suction line and insulate both
with “Presstite.” Ensure that retaining straps are
tight. (See Figure 4-8.)
k. Evacuate and dehydrate. (Refer to paragraph 4.6.)
l. Open filter-drier inlet valve (liquid line service valve)
and all service valves.
m.Run the coach for approximately 30 minutes on fast
idle.
(See
n.Check refrigerant level. (Refer to paragraph 4.7.1.)
a. Pump down low side of the unit. (Refer to paragraph
4.4.)
o.Check superheat. (Refer to paragraph 4.11.3.)
Braze Rod
(’Sil-Phos” = 5.5% Silver, 6% Phosphorus)
Copper Tube
(Apply heat for
10-15 seconds)
Bi-metallic Tube Connection
(Apply heat for 2-5 seconds)
Use of a wet cloth is not necessary due to rapid heat dissipation
of the bi--metallic connections
Figure 4-7. Hermetic Thermostatic Expansion Valve Brazing Procedure
T-310
4-8
i. Note the temperature of the suction gas at the
expansion valve bulb. Subtract the saturation
temperature determined in step h. from the
temperature measured in this step. The difference is
the superheat of the suction gas.
3
j. Repeat steps h. and i. six times at three minute
intervals and average the six readings to determine
average superheat. Average superheat should be 12
to 18_F (6.7 to 10.1_C).
4
2
5
1
1.
2.
3.
4.
5.
Suction Line (end view)
TXV Bulb Clamp
Nut and Bolt (clamp)
Thermocouple
TXV Bulb (Shown in the
four o’clock position)
4.12 MODEL 05G COMPRESSOR MAINTENANCE
4.12.1 Removing the Compressor
If compressor is inoperative and the unit still has
refrigerant pressure, isolate the compressor and remove
the refrigerant. Refer to paragraph 4.4.3.
If compressor is operative, perform a pump down.
(Refer to paragraph 4.4.4.)
Figure 4-8. Thermostatic Expansion Valve
Bulb and Thermocouple Installation
a. Turn main battery disconnect switch to OFF position.
4.11.3 To Check/Measure Superheat
b. Loosen bolts at suction and discharge service valve
flanges and break seal to be sure pressure is released.
The Micromate Control Panel can give this value.
(Refer to paragraph 3.1.1) The alternate method is
desribed as follows:
c. Remove bolts from suction and discharge service
valve flanges.
NOTE
All readings must be taken from the suction
side area of the evaporator near the TXV and
out of the direct air stream.
d. Tag and disconnect wiring to the high pressure cutout
switch, discharge pressure transducer, suction
pressure transducer, unloaders and the clutch.
g. Remove four bolts holding compressor to base.
h. Attach sling or other device to the compressor and
remove compressor from the coach through the right
rear access door.
a. Remove passenger evap. access door.
b. Remove Presstite insulation from expansion valve
bulb and suction line.
i. Remove the three socket head capscrews from both
unloader valves on the side heads of the 05G
compressor. Remove the unloader valve and bypass
piston assembly, keeping the same capscrews with
the assembly. (See Figure 4-9.) The original unloader
valve must be transferred to the replacement
compressor. The plug arrangement removed from the
replacement is installed in the original compressor as
a seal. If piston is stuck, it may be extracted by
threading a socket head capscrew into top of piston. A
small Teflon seat ring at the bottom of the piston must
be removed.
c. Loosen one TXV bulb clamp and make sure area
under clamp (above TXV bulb) is clean.
d. Place temperature thermocouple in contact with the
suction tube and parallel to the TXV bulb, and then
secure loosened clamp making sure both bulbs are
firmly secured to suction line. (See Figure 4-8.)
Reinstall insulation around the bulb.
e. Reinstall evaporator access door being careful to
route thermocouple sensing wire outside the
evaporator.
GASKET
f. Connect an accurate low pressure gauge to the 1/4”
port on the suction line within the passenger
evaporator compartment.
SPRING
FLANGE
COVER
COMPRESSOR
HEAD
g. Start coach and run on fast idle until unit has
stabilized, about 20 to 30 minutes.
CAPSCREWS
BYPASS
PISTON
PLUG
h. From the temperature/pressure chart, determine the
saturation temperature corresponding to the
evaporator outlet pressure. (See Table 4-5.) Add an
estimated suction line loss of 2 psig (13.8 kPa) to the
number.
(NOT INTERCHANGEABLE WITH
CONTROL VALVE SCREWS)
Figure 4-9. Removing Bypass Piston Plug
4-9
T-310
10--
NOTES
3
4
2
1. The service replacement 05G compressors
are sold without shutoff valves. Valve pads
are installed in their place. The optional
unloaders are not supplied, as the cylinder
heads are shipped with plugs. The
customer should retain the original
unloader valves for use on the replacement
compressor.
1
5
6
7
8
12
11
2. The piston plug that is removed from the
replacement compressor head must be
installed in the failed compressor if
returning for warranty.
9
10
7. Clutch
1. Discharge Service
8. Oil Fill Plug
Valve
9. Bottom Plate
2. Service Port
10. Oil Drain Plug
3. Electric Unloader
11. Oil Level Sight
Valve
Glass
4. O’Ring
12. Oil Pump
5. Suction Service
Valve Service Port
6. Suction Service
Valve
Figure 4-10. O5G Compressor
3. Do not interchange allen head capscrews
that mount the piston plug and unloader;
they are not interchangeable.
4. Check oil level in service replacement
compressor. (Refer to paragraph 4.12.2.)
5. Service replacement compressors are
supplied with a suction filter sock for initial
startup. Ensure the filter sock is installed
and removed in accordance with the
instructions furnished.
4.12.2 Compressor Oil Level
NOTE
The compressor should be fully loaded (six
cylinder operation); the unit should be fully
charged and the compressor crankcase should
be warm to the touch.
j. Remove the high pressure switch and pressure
transducer assemblies and install on replacement
compressor after checking switch operation.
k. Install compressor into the coach by performing steps
c. through h. in reverse sequence. It is recommended
that new locknuts be used when replacing
compressor. Install new gaskets on service valves and
tighten bolts uniformly.
a. Start the unit and allow the system to stabilize.
b. Check the oil sight glass on the compressor to ensure
that no foaming of oil is present after 20 minutes of
operation. If oil is foaming excessively after 20
minutes of operation, check the refrigerant system for
flood-back of liquid refrigerant. Correct this situation
before proceeding.
c. Check the level of oil in oil level sight glass
immediately after shutting down the compressor. The
lowest level visible should be at the bottom of the
sightglass and the highest level should be at the
middle of the sight glass. (See Figure 4-10.)
l. Unlock and turn main battery disconnect switch to
ON position..
m.Attach two lines (with hand valves near vacuum
pump) to the suction and discharge service valves.
(Dehydrate and evacuate compressor to 500 microns
(29.90” Hg vacuum = 75.9 cm Hg vacuum). Turn off
valves on both lines to pump.
4.12.3 Adding Oil with Compressor in System
n. Fully backseat (open counterclockwise) both suction
and discharge service valves.
The only recomended proceedure for adding POE oil to
a compressor is to pump it in from a sealed container.
o. Remove vacuum pump lines and install manifold
gauges.
NOTE
Special care must be taken when working
with POE oil that is used with HFC
refrigerants such as R--134a, as POE oil is
very hygroscopic. (POE oil will easily absorb
water.) Do not leave POE oil containers open
to the atmosphere.
p. Start unit and check refrigerant level. (Refer to
paragraph 4.7.1.)
q. Check compressor oil level. (Refer to paragraph
4.12.2.) Add or remove oil if necessary.
r. Check compressor unloader operation.
T-310
4-10
a. One compressor oil pump that may be purchased is a
Robinair part no. 14388. This oil pump adapts to one
U.S. gallon (3.785 liters) metal refrigeration oil
container and pumps 2-1/2 ounces (72.5 milliliters)
per stroke when connected to the suction service
valve port. Also, there is no need to remove pump
from can after each use.
b. When the compressor is in operation, the pump check
valve prevents the loss of refrigerant while allowing
servicemen to develop sufficient pressure to
overcome the operating suction pressure to add oil, as
necessary.
c. Backseat suction service valve and connect oil
charging hose to port. Crack open the service valve
and remove air from the oil hose at the oil pump. Add
oil as necessary.
the compressor. Replace the plug securely back into
the compressor.
d. Repeat step a. to ensure proper oil level.
Table 4-1. Temperature Sensor
(AT, TSC, TSD and TSR) Resistance
Temperature
Resistance In Ohms
_F
_C
--20
--10
0
10
20
30
32
40
50
60
70
77
80
90
100
110
120
4.12.4 Adding Oil to Service Replacement
Compressor
Service replacement compressors may or may not be
shipped with oil.
If the replacement compressor is shipped without oil,
add oil through the oil fill plug. (See Figure 4-10.)
4.12.5 Removing Oil from the Compressor:
a. If the lowest oil level observed in paragraph 4.12.2,
step c., is above middle of the sight glass on
compressor crankcase, oil must be removed from the
compressor by performing the following procedure.
If lowest oil level visible is below bottom of the
sightglass, oil must be added to the compressor by
following the procedure in paragraph 4.12.3.
b. Close (frontseat) suction service valve and pump unit
down to 3 to 5 psig (21 to 34 kPa). Reclaim remaining
refrigerant.
--28.9
--23.3
--17.8
--12.2
-- 6.7
-- 1.1
0
4.4
10.0
15.6
21.1
25
26.7
32.2
37.8
43.3
48.9
165,300
117,800
85,500
62,400
46,300
34,500
32,700
26,200
19,900
15,300
11,900
10,000
9,300
7,300
5,800
4,700
3,800
4.13 TEMPERATURE SENSOR CHECKOUT
a. An accurate ohmmeter must be used to check
resistance values shown in Table 4-1.
NOTE
If oil drain plug is not accessible, it will be
necessary to extract oil through the oil fill plug
with a siphon tube.
b. Due to variations and inaccuracies in ohmmeters,
thermometers or other test equipment, a reading
within two percent of the chart value would be
considered good. If a sensor is bad, the resistance
value would usually be much higher or lower than the
value given in the Table 4-1.
WARNING
EXTREME CARE MUST BE TAKEN TO
ENSURE
THAT
ALL
THE
REFRIGERANT HAS BEEN REMOVED
FROM
THE
COMPRESSOR
CRANKCASE OR THE RESULTANT
PRESSURE
WILL
FORCIBLY
DISCHARGE COMPRESSOR OIL.
c. At least one sensor lead must be disconnected from
the controller before any reading can be taken. Not
doing so will result in a false reading. Two preferred
methods of determining the actual test temperature at
the sensor are an ice bath at 32_F (0_C) and/or a
calibrated digital temperature meter.
d. If the driver display indicates that temperature at
sensor is --40_F (--40_C), sensor could be open. If
driver display indicates that temperature at sensor is
127_F (52.8_C), sensor could be shorted.
c. Remove the oil drain plug on the bottom plate of the
compressor and drain the proper amount of oil from
4-11
T-310
Table 4-2. Suction and Discharge Pressure
Transducer (SPT and DPT) Voltage
Psig Voltage Psig Voltage Psig Voltage
d. Connect wiring to replacement sensor or transducer.
e. Checkout replacement sensor or transducer. (Refer to
paragraph 4.13 or 4.14 as applicable.)
20”
10”
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
4.16 SERVICING PASSENGER EVAPORATOR AIR
FILTER
0.369
0.417
0.466
0.515
0.564
0.614
0.663
0.712
0.761
0.810
0.858
0.907
0.956
1.007
1.054
1.103
1.152
1.204
1.250
1.299
1.348
1.397
1.446
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
1.495
1.544
1.593
1.642
1.691
1.740
1.789
1.838
1.887
1.936
1.985
2.034
2.083
2.132
2.181
2.230
2.279
2.328
2.377
2.426
2.475
2.524
2.573
220
225
230
235
240
245
250
255
260
265
270
275
280
285
290
295
300
305
310
315
320
325
330
2.622
2.671
2.720
2.769
2.818
2.867
2.916
2.965
3.014
3.063
3.112
3.161
3.210
3.259
3.308
3.357
3.406
3.455
3.504
3.553
3.602
3.651
3.700
a. Turn main battery disconnect switch to OFF position.
b. Remove evaporator access door.
c. Rotate two clips securing the top of the filter to the
face of the evaporator.
d. Remove the filter taking care not to catch the filter on
wire harness or refrigerant tubing.
e.Re-install by performing the above procedure in
reverse.
4.17 SERVICING PASSENGER EVAPORATOR
MOTOR
a. Turn main battery disconnect switch to OFF position.
b. Remove evaporator access door.
c. Disconnect electrical connections.
d. Remove the support bracket connecting the blower
housing to the motor bracket assembly.
e. Remove the mounting bolts securing the motor
bracket/motor assembly to the frame of the
evaporator..
f. Remove the four screws securing the blower housing
venturi ring to the blower housing.
g. Remove the motor bracket, the motor and the blower
wheel as an assembly, sliding out of blower housing,
and removing from the evaporator.
h. Repair or replace any defective component(s), as
required.
4.14 SUCTION AND DISCHARGE PRESSURE
TRANSDUCER CHECKOUT
System must
transducers.
NOTE
be operating
to
4.18 SERVICING PASSENGER EVAPORATOR
MOTOR BRUSHES
a. Turn main battery disconnect switch to OFF position.
b. Remove evaporator access door.
c. Remove wires from terminals A1 and A2.
d. Remove cover exposing brushes.
e. Inspect brushes and replace as necessary.
check
a. With the system running, use the driver display or
manifold gauges to check suction and/or discharge
pressure(s).
4.19 SERVICING THE PASSENGER
EVAPORATOR/HEATER COIL
b. Use a digital volt-ohmmeter to measure voltage
across the transducer and compare to values in
Table 4-2. A reading within two percent of the values
in the table would be considered good.
NOTE
The evaporator/heater coil module must be
removed from the coach for service.
4.15 REPLACING SENSORS AND
TRANSDUCERS
a. Pump down low side of the HVAC system. (Refer to
paragraph 4.4.1.)
b. Remove remaining refrigerant. (Refer to paragraph
4.4.)
c. Turn main battery disconnect switch to OFF position.
a. Turn main battery disconnect switch to OFF position.
b. Tag and disconnect wiring from defective sensor or
transducer.
c. Remove and replace defective sensor or transducer.
T-310
4-12
l. Remove condenser coil assembly.
m.Repair or replace the condenser coil.
n.Re-install by performing the above procedure in
reverse.
d. Disconnect refrigerant lines at the refrigerant liquid
inlet connection, the suction outlet connection, and
the liquid line driver’s connection.(See Figure 1-5)
e. Loosen hex nut securing suction tube to suction tube
support bracket.
NOTE
Torque values for ORS fittings(See Table 4-4)
f. Plug up the copper tube outlets.
g. Drain engine coolant from the heater coil.
h. Remove the heater coil hoses from the heater coil
inlet and outlet connections.
4.21 SERVICING THE CONDENSER MOTOR
a. Turn main battery disconnect switch to OFF position.
b. Remove front condenser shroud.
c. Remove fan blade, secure the shaft key to the fan hub
slot.
d. Disconnect the wires to the motor.
e. Remove the four motor base mounting screws.
f. Remove the motor and place on workbench.
g. Repair or replace defective component(s), as
required.
h. Re-install by performing the above procedure in
reverse.
i. Disconnect the suction temperature sensor.
j. Remove the air filter.
k. Remove the two coil mount brackets. (See
Figure 1-5)
l. Remove the 10 screws securing the coil to the
housing and removable flange.
m.Remove the removable flange.
n. Remove evaporator/heater coil.
o. Repair or replace defective component(s), as
required.
p.Re-install by performing the above procedure in
reverse.
4.22 SERVICING CONDENSER MOTOR BRUSHES
a. Turn main battery disconnect switch to OFF position.
b. Remove front condenser shroud.
c. Remove fan blade, secure the shaft key to the fan hub
slot.
d. Inspect brushes and replace as necessary.
e. Re-install by performing the above procedure in
reverse.
NOTE
Torque values for ORS fittings(See Table 4-4)
4.20 SERVICING THE CONDENSER COIL
NOTE
The condenser assembly module must be
removed from the coach to service the
condenser coil.
4.23 SERVICING THE DRIVER EVAPORATOR
4.23.1 Access(Bottom) Cover Removal
g. Remove the condenser assembly module from the
coach.
a. Turn main battery disconnect switch to OFF position.
b. Open access door located in front of left front wheel
of coach.
c. Using a flat screwdriver, unfasten four 1/4 turn
fasteners from access cover on driver evaporator
assembly.
d. Remove the two condensate drain hoses from access
cover.
e. Remove the nine screws securing the access cover to
the evaporator housing.(Four screws each side and
one on the back side
f. Remove the access cover.
h. Remove both front upper and lower covers.
4.23.2 Blower Removal
i. Remove the condenser motors and support rails.
a. Remove bottom access cover (step 4.23.1).
b. Disconnect packard plug from the blower and speed
controller.
c. Undo motor mount screws (two per motor).
d. Drop the blower down and remove.
a. Remove and reclaim the entire refrigerant charge.
(Refer to paragraph 4.4.2.)
b. Turn main battery disconnect switch to OFF position.
c. Disconnect all electrical leads to the module.
d. Disconnect refrigerant lines to the module.
e. Remove the six mounting bolts located underneath
the base of the unit.
f. Remove the two condenser support braces securing
the top of the condenser to the coach. (See Figure 1-2)
j. Unbraze the discharge line assembly, the parcel
liquid line, the subcooler inlet and the subcooler
outlet tubes from the coil assembly.
k. Remove the top, left, and right panels.
4-13
T-310
g. Disconnect control circuit, battery, and ground
electrical leads.
h. Disconnect condensate drain lines.
i. Remove screws securing driver evaporator to the
coach, remove assembly from coach, and place on a
secure work surface.
j. Remove the top panel of the evaporator housing.
k. Remove the nuts securing the liquid and suction lines
to the back of the evaporator housing.
l. Remove the screws securing the back of the
evaporator housing, and remove the panel.
m.Unclip the liquid line solenoid valve and heat valve
coil from the harness.
n.Remove the screws securing the evaporator/heater
core to the housing.
o.Lift evaporator/heater coil up and place on a work
surface.
p. Re-install by performing the above procedure in
reverse.
NOTE
The lower motor will need to be removed if the
upper motor needs to be serviced.
e. Re-install by performing the above procedure in
reverse, being careful not to overtighten the blower
mounting screws.
4.23.3 Coolant/Solenoid Valve Coil Replacement
a. Remove bottom access cover (step 4.23.1).
b. Remove both blower motor assemblies (step 4.23.2)
to access the coolant valve. The solenoid valve will
require that only the lower blower be removed for
access.
c. Removal of either coil can now be accomplished by
unplugging the electrical lead, and removing the
retaining nut/screw.
d. Re-install by performing the above procedure in
reverse.
NOTE
Servicing of the valve bodies will require
removal of the Evapoator/heater coil assembly
(step 4.23.5).
NOTE
Torque values for ORS fittings(See Table 4-4)
4.23.4 Air Filter Removal
4.23.6 RAM Air Actuator Removal
a. Open the filter access door by loosening the four
quarter turn fasteners.
b. Slide filter up and out through the filter access door..
c. Clean/replace filter and re-install.
a. Turn main battery disconnect switch to OFF position.
b. Disconnect the packard plug.
c. Remove the no. 10 screw from the end of the spring
on the RAM air actuator.
d. Remove the actuator from its retaining clip.
e. Re-install by performing the above procedure in
reverse.
4.23.5 Removal
Assembly
of
Evaporator/Heater
Core
a. Pump down the refrigerant system. (Refer to
paragraph 4.4.1.)
b. Disconnect liquid line and suction line fittings..
c. Turn main battery disconnect switch to OFF position.
d. Drain engine coolant from the heater coil.
e. Remove the heater coil hoses from the heater coil
inlet and outlet connections.
f. Remove the screws securing the air duct support
brackets to the evaporator housing, and remove the
support brackets.
T-310
4.24 LOGIC BOARD CONFIGURATION
Control configuration is preset by the manufacturer and
resetting of the parameters is not advised. If a
replacement Logic Board is installed, it is necessary to
match the configuration jumpers (see Figure 1-10) to
the original board. Table 4-3 provides a list of jumper
functions. Carrier is not responsible for failures or
damage resulting from unauthorized changes.
4-14
Table 4-3. Logic Board Configuration
Configuration
Description
A.
High Reheat -- When this configuration is removed, the unit will default to high speed in reheat
mode and in the low speed cool band. If not removed, heat/reheat will default to low speed.
B.
High Vent -- When this configuration is removed, the unit will default to high speed in vent
mode. If not removed vent mode will default to low speed.
C.
Dry Heat-- When this configuration is removed, the unit will run on 100% reheat instead of
heat.
D.
Reheat/Cycle -- When the reheat cycle configuration is removed, the unit is in reheat mode.
The default configuration is cycle clutch mode.
E.
Transducers -- When the transducer configuration is removed, transducers will assume to be
present.
F.
Refrigerant R-22/R-134a -- When the refrigerant configuration is removed, the refrigerant is set
for R-22. The default refrigerant is R-134a.
G.
Unit Type -- Rearmount unit enabled with “G” removed and “H” installed.
H.
Unit Type -- With “H” removed and “G” installed, roof top unit will be enabled.
I.
Factory -- Reserved for the manufacturer.
J.
Invert H2O -- When this configuration is removed, the logic for the water temperature switch
will be inverted.
K.
Voltage -- When this configuration is removed, the voltage selection will be changed from 12 to
24 vdc.
L.
Factory -- Reserved for the manufacturer.
M.
Psig/Bars -- When this configuration is removed, the display will indicate pressures in bars.
When not removed, the display will indicate pressures in psig.
N.
C/F -- When this configuration is removed, the display will show temperatures in F. When
not removed the display will show temperatures in C.
O.
Loaded Start -- When this configuration is removed, the unit will start fully loaded instead of
staging the unloaders after the clutch is energized
P.
PI Reheat -- When this configuration is removed, reheat mode will use the PI algorithm to vary
the duty cycle of the heat valve. If it is not removed, the heat will be constant.
4-15
T-310
Table 4-4. Torque Ratings - ORS Connections
ORS Size
Thread
Torque
--4
--6
--8
--10
--12
--16
--20
9/16”--18
11/16”--16
13/16”--16
1”--14
1-3/16”--12
1-7/16”--12
1-11/16”--12
85--110 IN/LBS
125--160 IN/LBS
165--220 IN/LBS
325--400 IN/LBS
45--55 FT./LBS
65--80 FT./LBS
95--105 FT./LBS
Table 4-5. R-134a Temperature - Pressure Chart
Vacuum
Temperature
F
--40
.35
--30
--25
--20
--18
--16
C
--40
.37
--34
--32
--29
--28
--27
“/hg
Kg/cm@@
Bar
14.6
12.3
9.7
6.7
3.5
2.1
0.6
37.08
31.25
24.64
17.00
8.89
5.33
1.52
0.49
0.42
0.33
0.23
0.12
0.07
0.02
Temperature
F
--14
--12
--10
--8
--6
--4
--2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
T-310
C
--26
--24
--23
--22
--21
--20
--19
--18
--17
--16
--14
--13
--12
--11
--10
--9
--8
--7
--6
--4
--3
Temperature
F
28
30
32
34
36
38
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
Pressure
Psig
Kg/cm@@
Bar
0.4
1.2
2.0
2.9
3.7
4.6
5.6
6.5
7.6
8.6
9.7
10.8
12.0
13.2
14.5
15.8
17.1
18.5
19.9
21.4
22.9
0.03
0.08
0.14
0.20
0.26
0.32
0.39
0.46
0.53
0.60
0.68
0.76
0.84
0.93
1.02
1.11
1.20
1.30
1.40
1.50
1.61
0.03
0.08
0.14
0.20
0.26
0.32
0.39
0.45
0.52
0.59
0.67
0.74
0.83
0.91
1.00
1.09
1.18
1.28
1.37
1.48
1.58
4-16
C
--2
--1
0
1
2
3
4
7
10
13
16
18
21
24
27
29
32
35
38
41
43
46
49
52
54
57
60
63
66
68
Pressure
Psig
Kg/cm@@
Bar
24.5
26.1
27.8
29.6
31.3
33.2
35.1
40.1
45.5
51.2
57.4
64.1
71.1
78.7
86.7
95.3
104.3
114.0
124.2
135.0
146.4
158.4
171.2
184.6
198.7
213.6
229.2
245.6
262.9
281.1
1.72
1.84
1.95
2.08
2.20
2.33
2.47
2.82
3.20
3.60
4.04
4.51
5.00
5.53
6.10
6.70
7.33
8.01
8.73
9.49
10.29
11.14
12.04
12.98
13.97
15.02
16.11
17.27
18.48
19.76
1.69
1.80
1.92
2.04
2.16
2.29
2.42
2.76
3.14
3.53
3.96
4.42
4.90
5.43
5.98
6.57
7.19
7.86
8.56
9.31
10.09
10.92
11.80
12.73
13.70
14.73
15.80
16.93
18.13
19.37
SECTION 5
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.
5-1
T-310
LEGEND
SYMBOL
DESCRIPTION
ACSL A/C FAIL SIGNAL
ATS
AMBIENT TEMPERATURE SENSOR
BPS
BOOST PUMP SIGNAL
CB
CIRCUIT BREAKER
CFR
CONDENSER FAN REALY
CL
COMPRESSOR CLUTCH
CM
CONDENSER FAN MOTOR
COL
CONDENSER FAN MOTOR OVERLOAD
CSR
CONDENSER SPEED RELAY
DPT
DISCHARGE PRESSURE TRANSDUCER
DRAS DRIVER RETURN AIR SENSOR
EFR
EVAPORATOR FAN RELAY
EM
EVAPORATOR FAN MOTOR
EOL
EVAPROATOR FAN MOTOR OVERLOAD
ESR
EVAPORATOR SPEED RELAY
F
FUSE
HPS
HIGH PRESSURE SWITCH
K1
EVAPORATOR 1/2 RELAY
K2
EVAPORATOR HIGH SPEED RELAY
K7
CF1/2 RELAY
K8
CONDENSER HIGH SPEED RELAY
K13
CLUTCH RELAY
K14
UV1 RELAY
K15
UV2 RELAY
K17
HEAT RELAY
K18
FAULT RELAY
K19
BOOST PUMP RELAY
K20
DRIVER LSV RELAY
K21
EVAPORATOR FAN HIGH RELAY
K22
EVAPORATOR FAN LOW RELAY
K23
CONDENSER FAN HIGH RELAY
LED
LIGHT EMITTING DIODE
LPS
LOW PRESSURE SWITCH
LSV
LIQUID LINE SOLENOID VALVE
MCP
MICORMATE CONTROL PANEL
PR
POWER RELAY
R1
RESISTOR, 1500 OHMS, SW (OEM SUPLIED)
RAS
RETURN AIR SENSOR
RCV
REHEAT COOLENT VALVE (HEAT VALVE)
SPT
SUCTION PRESSURE TRANSDUCER
STS
SUCTION TEMPERATURE SENSOR
UV
UNLOADER SOLENOID VALVE
WTS
WATER TEMPERATURE SWITCH
SYMBOLS
CONNECTOR TERMINAL
GROUND
WIRING ON BOARD
FACTORY WIRING
OEM WIRING
GROUND STUD
POWER STUD
CONNECTOR
NORMALLY CLOSED CONTACT
NORMALLY OPEN CONTACT
A
CONNECTOR, POSITON ”A”
LAMP
DIODE
FUSE
COIL
MOTOR (EF or CF)
PRESSURE SENSOR
LED ASSEMBLY
PRESSURE SWITCH
TEMPERATURE SENSOR
MANUAL RESET BREAKER
CONNECTOR LEGEND
SYMBOL
RELAY COIL
J1
J2
J3
J4
J5
J6
J7
JP1
JP2
JP3
JP4
JP5
JP6
JP7
JP8
JP9
MANUAL SWITCH
POLY SWITCH
TEMPERATURE SWITCH
MULTI--PLEX MODULE
RIBBON CABLE
DESCRIPTION
LOGIC POWER CONNECTOR
DISPLAY INTERFACE
ON/TEST CONNECTOR
INPUT CONNECTOR
RELAY BOARD INTERFACE CONNECTOR
SENSOR CONNECTOR
DIAGNOSTIC INTERFACE
MOTOR OVERLOAD CONNECTOR
LOGIC BOARD INTERFACE CONNECTOR
BOOST PUMP CONNECTOR
CLUTCH/FAIL CONNECTOR
HEAT CONNECTOR
UNLOADER VALVE CONNECTOR
EVAPORATOR FAN/SPEED CONNECTOR
12 VOLT POWER
CONDENSER FAN/SPEED CONNECTOR
Figure 5-1. Electrical Schematic Diagram Legend and Symbols
T-310
5-2
See Figure 5-1 for Legend and Symbols.
Figure 5-2. Wiring Schematic - Power Circuit
5-3
T-310
Figure 5-3. Wiring Schematic - Logic/Relay Board
T-310
5-4
(--)
(--)
(+)
J6
A
9
22
D
E
F
B
C
A
24
23
21
20
D
C
19
10
B
B
8
7
A
B
6
5
B
2
B
1
A
A
4
A
B
2
1
J4
6
4
5
3
2
J3
3
2
1
4
F
DRAS
STS
ATS
RAS
WTS
JUMPER
DATA
DATA
12V
GND
E
A
SEE FIG. 5--4
SEE FIG. 5--4
3
2
5
6
+24V
See Figure 5-1 for Legend and Symbols.
SPT
(+)
DPT
GRD
(PTB2)
MICROMATE
CONTROL
PANEL
(DISPLAY)
SEE FIG. 5--4
1
J1
J1
2
J5
GRD (PTB2)
4
J1
LOGIC BOARD
ON
J2
5
4
3
2
13
12
11
10
9
8
7
6
16
1
18
5
JC
4
JC
3
JC
2
JC
13
JC
12
JC
11
JC
10
JC
9
JC
8
JC
7
JC
6
JC
16
JC
1
JC
18
JC
K20
86
JA
JA
COND FAN HIGH RELAY
2
5
EVAP FAN LOW RELAY
2
5
K22
COND FAN LOW RELAY
2
5
K24
K23
HPS
9
19
EVAP FAN HIGH RELAY
2
5
K21
85
DRIVER LSV
BOOST RELAY
86
85
K19
FAULT RELAY
86
85
K18
HEAT RELAY
86
85
K17
FRESH AIR
86
85
K16
UV2 RELAY
86
85
K15
UV1 RELAY
86
85
K14
CLUTCH RELAY
86
85
K13
D9
24V
JA
4
JA
JA
12
JA
6
11
EOL
RELAY BOARD
D35
D4
CF ON RELAY
85
86
K7
D37
D24
CF HIGH SPEED RELAY
D36
85
86
K8
EF ON RELAY
86
85
K1
K2
EF HIGH SPEED RELAY
D34
86
85
GROUND
STUD
K24
CF LOW
K23
CF HIGH
K22
EF LOW
K21
EF HIGH
DRIVERS EVAPORATOR UNIT
SEE
Figure 5-2
JA-14 RELAY BOARD - SEE Figure 5-2
J3-2 LOGIC BOARD
J3-6 LOGIC BOARD
SEE Figure 5-3
J1-1 LOGIC BOARD
See Figure 5-1 for Legend and Symbols.
Figure 5-4. Wiring Schematic - Driver Evaporator
5-5
T-310
See Figure 5-1 for
Legend and Symbols.
Figure 5-5. Wiring Schematic Diagram
T-310
5-6
INDEX
A
Evacuation And Dehydration, 4-4
Evaporator Assemblies, 1-4
Air Conditioning Refrigerant Cycle, 1-13
Air Filter, 4-12, 4-14
Alarm, 2-5, 3-1
Evaporator Coils, 1-14
Evaporator Fan, 2-4
Alarm Clear, 3-1
F
Alarm Codes, 3-1
Alarm Queue, 3-1
Ambient Lockout, 1-12
Filter--Drier, 4-7
Fuse, 1-12
B
H
Boost Pump, 2-4
Heating Flow Cycle, 1-13
C
Capacity Control, 2-4
Checking For Noncondensibles, 4-6
Heating Mode, 2-2
Hour Meter, 2-5
Humidity Sensor, 4-12
Checking High Pressure Switch, 4-7
I
Checking Refrigerant Charge, 4-6
Circuit Breaker, 1-12
Clutch, 2-5
Compressor, 1-2, 1-3
Installing Manifold Guages, 4-2
Introduction, 1-1
Compressor Oil Level, 4-10
L
Compressor Removal, 4-9
Condenser Assembly, 1-2
Condenser Coil, 4-13
Liquid Line Solenoid, 2-5
Condenser Fan, 2-4
Logic Board, 2-1, 4-14
Condenser Motor, 4-13
Coolant/Solenoid Valve Coil,4-14
M
Cooling Mode, 2-2
Main Evaporator Motor, 4-12
D
Diagnostics, 2-2, 3-1,3-3
Main Evaporator Or Heater Coil, 4-12
Maintenance Schedule, 4-1
Modes Of Operation, 2-2
Discharge Pressure, 2-4
Driver Evaporator, 4-13
O
Driver Evaporator, 1-4
Driver/Parcel Control, 2-1
E
Oil Charge, 1-11
Oil: Adding Charge, 4-10
Operating Controls, 1-6
Electrical Specifications -- Controls, 1-11
Operating Instructions, 2-1
Electrical Specifications -- Motors, 1-11
OPERATION, 2-1
Index-1
T-310
INDEX
P
Starting, 2-1
Suction and Discharge Service Valves, 4-1
PassengerEvaporator Assembly, 1-5
Suction Pressure, 2-4
Pre--Trip Inspection, 2-2
Superheat -- Check/Measure, 4-9
Pressure Transducer, 4-12
System Parameters, 3-1
System Pumpdown, 4-2
R
System Service, 4-1
Refrigerant Charge, 1-11, 4-6
T
Refrigerant Charge Removal, 4-3
Refrigerant Leak Check, 4-3
Temperature Control, 2-2
Refrigerant Removal From Compressor, 4-3
Temperature Pressure Chart, 4-16
Refrigerant Service Connections, 4-5
Temperature Sensor, 4-11
Refrigeration System Components, 1-11
Thermostatic Expansion Valve, 4-7
Replacing High Pressure Switch, 4-7
TROUBLESHOOTING, 3-1
U
S
Safety Devices, 1-12
Unloaders, 2-4
Schematic Diagram, 5-3, 5-4, 5-5, 5-6
V
Self Diagnostics, 3-1
Shut Down, 2-2
T-310
Vent Mode, 2-4
Index-2