Bus Air
Conditioning
Equipment
Models
GR--45
GR--60
(N. A. O.)
T--295
OPERATION AND
SERVICE MANUAL
BUS
AIR CONDITIONING
UNIT
Models
GR--45
GR--60
(N. A. O.)
Carrier Refrigeration Operations
Carrier Transicold Division, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221 U. S. A.
Carrier Corporation 2000 D Printed in U. S. A. 0300
SAFETY SUMMARY
GENERAL SAFETY NOTICES
The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this
manual. They are recommended precautions that must be understood and applied during operation and maintenance
of the equipment covered herein. A listing of the specific warnings and cautions appearing elsewhere in the manual
follows the general safety notices.
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 placed in the OFF
position, 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 unit cover before turning
power off.
Be sure power is turned off before working on motors, controllers, solenoid valves and electrical controls. 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).
SPECIFIC WARNINGS AND CAUTIONS
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.
WARNING
THE FILTER-DRIER MAY CONTAIN LIQUID REFRIGERANT. SLOWLY LOOSEN THE
FLARE NUTS AND AVOID CONTACT WITH EXPOSED SKIN OR EYES.
CAUTION
Do not under any circumstances attempt to service the microprocessor. should a problem develop with
the microprocessor, replace it.
CAUTION
If unit was recently operated, be careful of remaining hot coolant in the hoses when disassembling.
Safety-1
T--295
TABLE OF CONTENTS
PARAGRAPH NUMBER
Page
SAFETY SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety-1
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
1.1
1.2
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.1 Apex Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.2 Condensing Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.3 Evaporator Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.4 Compressor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.5 Fresh Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2.6 System Operating Controls And Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . .
1.4 ELECTRICAL SPECIFICATIONS -- MOTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 ELECTRICAL SPECIFICATIONS -- SENSORS AND TRANSDUCERS . . . . . . . . . . . . . . . . . .
1.6 SAFETY DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7 AIR FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 AIR CONDITIONING REFRIGERATION CYCLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.9 HEATING CYCLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10 RELAY BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.1 Permanent Magnet Motors with 2 speed switching from series to parallel
connection (Option 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.2 Electronically Communtated DC Motors with 2--speed Evaporator Input Signal (Option 2) .
1.11 LOGIC BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.12 CONTROL PANEL (Diagnostic Module) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-9
1-11
1-12
1-13
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1
2.1
STARTING, STOPPING AND OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.1 Power to Logic Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.2 Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.3 Self-Test and Diagnostics (Check for Errors and/or Alarms) . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.4 Stopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 PRE--TRIP INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 MODES OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.1 Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.2 Cooling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.3 Heating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.4 Boost Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.5 Vent Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.6 Fresh Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.7 Compressor Unloader Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.8 Evaporator Fan Speed Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.9 Condenser Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.10 Compressor Clutch Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
1-1
1-2
1-2
1-2
1-3
1-4
1-4
1-4
1-5
1-5
1-5
1-5
1-6
1-6
1-8
1-9
2-1
2-1
2-1
2-1
2-1
2-1
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-4
2-4
2-4
T--295
TABLE OF CONTENTS (Continued)
PARAGRAPH NUMBER
2.3.11
2.3.12
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
Page
Alarm Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hour Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MICROPROCESSOR DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-4
2-4
2-4
2-4
2-5
2-5
2-5
2-5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1
3.1
3.2
SELF DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SYSTEM ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 Alarm Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.3 Alarm Queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.4 Alarm Clear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1 System Will Not Cool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 System Runs But Has Insufficient Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3 Abnormal Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4 Abnormal Noise Or Vibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.5 Control System Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.6 No Evaporator Air Flow Or Restricted Air Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.7 Expansion Valve Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.8 Heating Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1
3-1
3-1
3-1
3-1
3-1
3-1
3-4
3-4
3-4
3-4
3-5
3-5
3-5
3-5
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-1
4.1
4.2
4.3
4.4
4.5
MAINTENANCE SCHEDULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OPENING TOP COVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SUCTION AND DISCHARGE SERVICE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INSTALLING MANIFOLD GAUGE SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PUMPING THE SYSTEM DOWN OR REMOVING THE REFRIGERANT CHARGE . . . . . . .
4.5.1 System Pump Down For Low Side Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.2 Refrigerant Removal From An Inoperative Compressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.3 Pump Down An Operable Compressor For Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.4. Removing Entire System Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 REFRIGERANT LEAK CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 EVACUATION AND DEHYDRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.3 Procedure for Evacuation and Dehydrating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T--295
ii
4-1
4-1
4-1
4-2
4-2
4-2
4-3
4-3
4-4
4-4
4-4
4-4
4-4
4-4
TABLE OF CONTENTS (Continued)
PARAGRAPH NUMBER
4.8
Page
ADDING REFRIGERANT TO SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8.1 Checking Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
4-5
4.8.2 Adding Full Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8.3 Adding Partial Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9 CHECKING FOR NONCONDENSIBLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
4-5
4-5
4.10 CHECKING AND REPLACING HIGH PRESSURE SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11 FILTER-DRIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.1 To Check Filter--Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.2 To Replace Filter--Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
4-6
4-6
4-6
4.12 CONDENSER COIL REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.13 EVAPORATOR COIL REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.14 SERVICING THE HEAT VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.14.1 COIL REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.14.2 INTERNAL PART REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-6
4-7
4-7
4-7
4-7
4.14.3 REPLACE ENTIRE VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.15 SERVICING THE LIQUID LINE SOLENOID VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.15.1 Coil Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.15.2 Internal Part Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.15.3. Replace Entire Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.16 CONDENSER FAN/MOTOR ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.16.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.16.2 Inspection And Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.16.3 Brush Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.17 REPLACING EVAPORATOR FAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.18 REPLACING RETURN AIR FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.19 THERMOSTATIC EXPANSION VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.19.1 Valve Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.19.2 Superheat Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-7
4-8
4-8
4-8
4-8
4-8
4-8
4-9
4-9
4-9
4-9
4-9
4-9
4-10
4.20 COMPRESSOR MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-10
4.20.1 Removing the Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.20.2 Transferring Compressor Clutch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-10
4-11
4.20.3 Compressor Oil Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.20.4 Checking Unloader Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.21 TEMPERATURE SENSOR CHECKOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.22 PRESSURE TRANSDUCER CHECKOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.23 REPLACING SENSORS AND TRANSDUCERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-12
4-12
4-13
4-13
4-13
4.24 LOGIC BOARD CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-13
ELECTRICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1
5--1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iii
Index-1
T--295
LIST OF ILLUSTRATIONS
FIGURE NUMBER
Page
Figure 1-1. A/C Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-2. Apex Unit Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-3. Condensing Section Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-4. Evaporator Section Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-5. Air Flow Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-6. Refrigerant Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-7. Heating Cycle Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-8 Relay Board (Option 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-9 Relay Board (Option 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-10 Logic Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1-11. Micromate Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 2-1 Capacity Control Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-1. Opening Top Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-2.Suction or Discharge Service Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-3. Manifold Gauge Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-4. Low Side Pump Down Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-5. Compressor Service Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-6. System Charge Removal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-7. Checking High Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-8. Filter--Drier Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-9. Heat Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-10. Liquid Line Solenoid Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-11. Condenser Fan/Motor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-12. Evaporator Fan Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-13. Thermostatic Expansion Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-14.Thermostatic Expansion Valve Bulb and Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-15.Removing Bypass Piston Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-16. Compressor Clutch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-17. Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-18 Transducer Terminal Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 5--1. Electrical Wiring Schematic Diagram - Legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 5--2. Wiring Schematic, Permanent Magnet Motors - Interconnection . . . . . . . . . . . . . . . . . . . . . . .
Figure 5--3. Wiring Schematic, Permanent Magnet Motors - Relays to External Components . . . . . . . . . .
Figure 5--4. Wiring Schematic, Electronically Communtated Motors - Interconnection . . . . . . . . . . . . . . .
Figure 5--5. Wiring Schematic, Electronically Communtated Motors - Relays To External Components . .
T--295
iv
1-1
1-2
1-3
1-4
1-6
1-7
1-8
1-9
1-11
1-12
1-13
2-2
4-1
4-2
4-2
4-3
4-3
4-4
4-6
4-6
4-7
4-8
4-8
4-9
4-9
4-10
4-11
4-11
4-12
4-13
5-2
5-3
5-4
5-5
5-6
LIST OF TABLES
TABLE NUMBER
Page
Table 2-1. Evaporator Fan Speed Relay Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 2-2. Controller Test List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 2-3. Parameter Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 3-2 Alarm Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 3-3 General System Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 4-1. Temperature Sensor Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 4-2. PressureTransducer Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 4-3. Logic Board Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
v
2-4
2-5
2-6
3-2
3-4
4-13
4-14
4-14
T--295
SECTION 1
DESCRIPTION
1.1 INTRODUCTION
system, the air conditioning and heating equipment
interfaces with electrical cabling, refrigerant piping,
engine coolant piping (for heating), duct work and other
components furnished by the bus manufacturer.
This manual contains Operating Instructions, Service
Instructions and Electrical Data for the Model GR Air
Conditioning and Heating equipment furnished by
Carrier Transicold Division as shown in Table 1-1.
Model GR systems consists of an Apex Unit, containing
the condenser and evaporator and an engine
compartment mounted compressor. To complete the
Operation of the units is controlled automatically by a
microprocessor based Micromax Controller which
maintains the vehicle’s interior temperature at the
desired set point.
MODEL
SERIES
Table 1-1. Model
COMPRESSOR
GR45
ROOF MOUNTED
ROOF MOUNTED
05K
05G
GR60
CONDENSER
FANS
EVAPORATOR
FANS
4
6
4
6
MANUAL/FORM NUMBER
Table 1-2. Additional Support Manuals
EQUIPMENT COVERED
TYPE OF MANUAL
62--02491
62--02460
62--02756
T--200
O5K Compressor
O5K Compressor
O5G Compressor
O5G Compressor
Operation and Service
Parts List
Operation and Service
Parts List
5
8
7
6
4
3
2
1
13
1.
2.
3.
4.
5.
6.
7.
12
11
Compressor
Refrigerant Lines
Compressor Harness
Heat Valve
Electronics Boards
Apex Unit
Main Harness
10
9
8.
9.
10.
11.
12.
13.
Driver Control
Power Harness
Power Relay
Battery
Alternator
Discharge Check Valve
Figure 1-1. A/C Component Identification
1-1
T--295
1.2 GENERAL DESCRIPTION
section, evaporator section, Micromax electronics, and
the Fresh Air System. All components are accessible by
lifting the top cover. Descriptions of the systems are
provided in the following sub paragraphs.
1.2.1 Apex Unit
The apex unit (see Figure 1-2) includes the condensing
2
1
3
11
10
4
5
6
8
9
1. Top Cover
2. Gas Spring (2)
3. Condenser Section (See Figure 1-3)
4. Evaporator Section (See Figure 1-4)
5. Base
6. Fresh Air System
7. Gas Spring Support (2)
8. Lock (2)
9. Serial Plate
7
10.
11.
Hinge
Condenser Fan Grille (4-GR45,
6-GR60)
12. Front Drain (2)*
13. Intermediate Drain (2)*
14. Evaporator Rear Drain (2)*
15. Condenser Rear Drain (2)*
* Not Shown
Figure 1-2. Apex Unit Components
(GR-60 Shown)
pressure into a liquid at high temperature and pressure.
The condenser fans circulate ambient air across the
The condensing section (Figure 1-3) includes the
outside of the condenser tubes at a temperature lower
condenser coils, fan and motor assemblies, filter-drier,
than refrigerant circulating inside the tubes; this results
receiver, liquid line solenoid valve, service valves, and
in condensation of the refrigerant into a liquid. The
an ambient temperature sensor.
filter-drier removes moisture and debris from the liquid
The condenser coils provide heat transfer surface for
refrigerant before it enters the thermostatic expansion
condensing refrigerant gas at a high temperature and
valve in the evaporator assembly.
1.2.2 Condensing Section
T--295
1-2
The receiver collects and stores liquid refrigerant. The
receiver is fitted with upper and lower liquid level sight
glasses to enable determining refrigerant liquid level.
The receiver is also fitted with a fusible plug which
protects the system from unsafe high pressure
conditions. The liquid line solenoid valve closes when
system is shut down to prevent flooding of coils with
liquid refrigerant. The service valves enable isolation of
the filter-drier for service. The ambient temperature
1
2
sensor measures ambient temperature and sends an
electrical signal to the controller.
The discharge check valve is a spring loaded, normally
closed valve that opens with the flow of refrigerant from
the compressor. When the compressor clutch is
disengaged, the discharge check valve will close,
preventing the flow of high pressure liquid from the
condenser back into the compressor.
4
3
5
6
13
7
12
8
9
11
1.
2.
3.
4.
5.
6.
7.
8.
10
Condenser Coil (2)
Receiver
Protection Plate
Service Valve
Discharge Line
Precharge Valve
Liquid Line Solenoid Valve
Filter Drier Upper Support
9.
10.
11
12.
13.
Filter Drier
Filter Drier Lower Support
Condenser Fan and Motor Assembly
(4-GR45, 6-GR60)
Condenser Coil Fastener (4)
Condenser Motor Support
(4-GR45, 6-GR60)
Figure 1-3. Condensing Section Components
(GR-60 Shown)
circulating over the outside surface of the tubes, thus
providing heating. The fans circulate the air over the
The evaporator section (Figure 1-4) includes the
coils. The air filters remove dirt particles from the air
evaporator coils, six fan and motor assemblies,
before it passes over the coils. The thermostatic
evaporator/heater coil assemblies, a thermostatic
expansion valve meters flow of refrigerant entering the
expansion valve and condensate drain connections.
evaporator coils. The heat valve controls the flow of
The evaporator coils provide heat transfer surface for
engine coolant water to the heating coils upon receipt of
transferring heat from air circulating over the outside
a signal from the controller. The condensate drain
the coil to refrigerant circulating inside the tubes; thus
connections provide a means for connecting tubing for
providing cooling. The heating coils provide heat
disposing of condensate collected on the evaporator
transfer surface for transferring heat from engine
coils during cooling operation.
coolant water circulating inside the tubes to air
1.2.3 Evaporator Section
1-3
T--295
1
2
3
4
5
6
7
8
9
1.
2.
3.
4.
Evaporator Coil With Integrated
5. Evaporator Motor (4-GR45,
Heating Coil (2)
6-GR60)
Protection Plate
6. Suction Line
Expansion Valve
7. Heating Lines
Evaporator Motor Fastening Clamps
8. Service Valve
(4-GR45, 6-GR60)
9. Evaporator Harness
Figure 1-4. Evaporator Section Components
(GR-60 Shown)
into the air entering the evaporator coil. For additional
information on air flow, refer to paragraph 1.7.
The compressor assembly includes the refrigerant
compressor, clutch assembly, suction and discharge
1.2.6 System Operating Controls And Components
service valves, high pressure switch, low pressure
switch, suction and discharge servicing (charging) ports
The system is operated by a Carrier Transicold
and electric solenoid unloaders.
Micromax microprocessor controller which consist of a
logic board (Figure 1-10), relay board (Figure 1-8 or
The compressor raises the pressure and temperature of
Figure 1-9), and manual operator switches. The manual
the refrigerant and forces it into the condenser tubes.
operating switches are located on the drivers control and
The clutch assembly provides a means of belt driving
may consist of a single OEM supplied ON/OFF switch,
the compressor by the bus engine. The suction and
additional OEM supplied switches or a Carrier
discharge service valves enable servicing of the
Transicold supplied Micromate control panel
compressor. Suction and discharge servicing (charging)
(Figure 1-11). The logic board regulates the operational
ports mounted on the service valves enable connection
cycles of the system by energizing or de--energizing
of charging hoses for servicing of the compressor, as
relays on the relay board in response to deviations in
well as other parts of the refrigerant circuit. The high
interior temperature. Modes of operation include
pressure switch contacts open on a pressure rise to shut
Cooling, Heat and Vent. On systems fitted with only an
down the system when abnormally high refrigerant
ON/OFF switch and on systems with the Micromate set
pressures occur. The electric unloaders provide a means
in the AUTO mode, the logic board will cycle the
of controlling compressor capacity, which enables
system between the operating modes as required to
control of temperature inside the bus. For more detailed
maintain desired set point temperature.
information on the compressor, refer to manual number
62-02756.
In the vent mode the evaporator fans are operated to
circulate air in the bus interior.
1.2.5 Fresh Air System
The Fresh Air System (6, Figure 1-2) consists of a
In the heat mode the heat valve is opened to allow a flow
damper and damper operator. The damper operator may
of engine coolant through the heat section of the
be controlled by the driver, if a switch is provided. In the
evaporator coil. The evaporator fans operate to circulate
automatic mode, it is controlled by the Micromax to
air over the evaporator coil in the same manner as the
open and close the damper to allow addition of fresh air
vent mode.
1.2.4 Compressor Assembly
T--295
1-4
In the cooling mode the compressor is energized while
the evaporator and condenser fans are operated to
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 the clutch cycle or reheat mode. 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. A controller programmed for reheat will
maintain compressor operation and open 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.
ECDC*
p
Evaporator
Motor
27.5
VDC
Horsepower (kW)
Full Load Amps
(FLA)
Operating Speed
High/Low (RPM)
Bearing Lubrication
Horsepower (kW)
Full Load Amps
(FLA)
Operating Speed
High/Low (RPM)
Bearing Lubrication
1.3 REFRIGERATION SYSTEM COMPONENT
SPECIFICATIONS
14.3 lb (6.5 kg)
Compressor
No of Cylinders
Weight - Dry
Oil Charge
GR45
GR60
05K
4
108 lbs
(49 kg)
5.5 pints
(2.6 liters)
05G
6
137 lbs
(62 kg)
6.75 pints
(3.2 liters)
1/8 (.09)
9
18
1.5 ELECTRICAL SPECIFICATIONS -- SENSORS
AND TRANSDUCERS
a. Suction and Discharge Pressure Transducer
Supply Voltage: 4.5 to 5.5 vdc (5 vdc nominal)
Supply current: 8 mA maximum
Output Range: 8K ohms minimum
Input Range: --6.7 to 450 psig (--0.46 to 30.62 bar)
Output Current: -1.5 mA minimum to
1.5 mA maximum
Output Voltage: vdc = 0.0098 x psig + 0.4659
(See Table 4-2 for calculations.)
Oil Level:
Level in sight glass between Min.--Max marks on
compressor crankcase (curbside)
Approved Compressor Oils - R-134a:
Castrol: Icematic SW68C
Mobil: EAL Arctic 68
ICI: Emkarate RL68H
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.)
c. Thermostatic Expansion Valve:
Superheat Setting (Non-externally adjustable):
10 to 12F
MOP Setting (Nonadjustable): 55 ±4 psig (3.74
±2.27 bar)
1.6 SAFETY DEVICES
System components are protected from damage caused
by unsafe operating conditions with safety devices.
Safety devices with Carrier Transicold supplied
equipment include high pressure switch (HPS), low
pressure switch (LPS), circuit breakers and fuses.
d. High Pressure Switch (HPS):
Opens at: 300 ±10 psig (20.41 ±0.68bar)
Closes at: 200 ±10 psig (13.61 ±0.68bar)
a. Pressure Switches
High Pressure Switch (HPS)
During the A/C mode, compressor operation will
automatically stop if the HPS switch contacts open due
to an unsafe operating condition. Opening HPS contacts
de-energizes, through the controller, the compressor
clutch shutting down the compressor. The high pressure
switch (HPS) is installed in the center head of the
compressor.
e. Low Pressure Switch (LPS)
Opens at: 6 ±3psig (0.41 ±0.20 bar)
Closes at: 25 ±3 psig (1.7 ±0.20 bar)
1.4
0.15(.11)
7
Permanent
Magnet
24 VDC 12 VDC
4252/
4200/
NA
1850
Factory Lubricated (additional grease not required)
* Electronically Communicated Direct Current
a. Refrigerant Charge
b. Compressor
UNIT MODEL
1/8 (.09)
9.5
19
4252/
4200/
3165
1850
Factory Lubricated (additional grease not required)
b. Condenser Fan Motor
ECDC*
Condenser Motor
24 VDC
Controls may also be provided to allow manual
operation of the evaporator fans in low or high speed
and manual control of the fresh air damper in the open or
closed position.
R--134a
0.34(.25)
8.4
Permanent
Magnet
24 VDC 12 VDC
ELECTRICAL SPECIFICATIONS -- MOTORS
a. Evaporator Fan Motor
1-5
T--295
Low Pressure Switch (LPS)
The low pressure switch is installed in the compressor
and opens on a pressure drop to shut down the system
when a low pressure condition occurs. In addition, if the
control monitors a pressure less than 10 psig (0.68
bar)by the suction pressure transducer mounted in the
evaporator section, the system will be shut down for at
least one minute.
The compressor raises the pressure and the temperature
of the refrigerant and forces it 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
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.
b. Fuses and Circuit Breakers
The Relay Board is protected against high current by an
OEM supplied 150 amp fuse. Independent 15 amp
circuit breakers protect each motor while the output
circuits are protected by an additional 15 amp circuit
breaker. During a high current condition, the breaker (or
OEM fuse) may open. When power is removed from a
device, a breaker alarm will be generated.
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 a storage space when
pumping down the system. The receiver is equipped
with sight glasses to observe the refrigerant for
restricted flow and correct charge level.
c. Ambient Lockout
The refrigerant leaves the receiver and passes through
the receiver outlet/service valve, through a filter-drier
where an absorbent keeps the refrigerant clean and dry.
The ambient temperature sensor located in the
condenser section measures the condenser 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
may be programmed to cut out at 45F 7.2C) and cut in
at 50F 10C) or cut out at 25 F --3.9C) and cut in at
45F 7.2C) in accordance with bus purchase
specification. This setting protects the compressor from
damage caused by operation at low pressures.
From the filter-drier, the liquid refrigerant then flows
through the liquid line solenoid valve to the
thermostatic expansion valve. the thermal expansion
valve reduce 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.
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
fans (fans). Heat transfer is established from the
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 bus. Liquid line solenoid valve closes
during shutdown to prevent refrigerant flow.
1.7 AIR FLOW
The paths for ambient air through the condenser and
coach air through the evaporator are illustrated in
Figure 1-5.
1.8 AIR CONDITIONING REFRIGERATION
CYCLE
When air conditioning (cooling) is selected by the
controller, the unit operates as a vapor compression
system using R-134a as a refrigerant (see Figure 1-6).
The main components of the system are the
reciprocating compressor, air-cooled condenser coils,
receiver, filter-drier, thermostatic expansion valve,
liquid line solenoid valve and evaporator coils.
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.
CONDENSER AIR FLOW
3. THROUGH FAN
4. RETURN TO AMBIENT
2. THROUGH CONDENSER
1. FROM DAMPER
(IF ACTIVE)
1. FROM AMBIENT
2. FROM COACH
3. THROUGH EVAPORATOR
4. THROUGH FAN
5. RETURN TO COACH
Figure 1-5. Air Flow Paths
T--295
1-6
EVAPORATOR
AIR
FLOW
1
2
3
4
5
6
7
8
9
10
11
A
12
13
16
11
A
14
RECEIVER
16
DISCHARGE
LIQUID
SUCTION
DISCHARGE
SUCTION
15
17
MAIN ENGINE
RADIATOR
18
VIEW A-A
COMPRESSOR
1.
2.
3.
4.
5.
6.
7.
8.
9.
Condenser Fan Assembly
Evaporator Fan Assembly
Expansion Valve
Expansion Valve Equalizer Line
Liquid Line
Precharge Valve
Expansion Valve Bulb
Pressure Transducer, Low Side
Service Port, Low Side
10.
11.
12.
13.
14.
15.
16.
17.
18.
Pressure Transducer, High Side
Service Valve With Port
Liquid Line Solenoid Valve
Filter Drier
Service Port, High Side
Discharge Check Valve
Receiver
Refrigerant Sight Glass
Moisture Indicator
Figure 1-6. Refrigerant Flow Diagram
(GR60 Shown)
1-7
T--295
HEAT
VALVE
BOOST
PUMP
SUPPLY
RETURN
MAIN ENGINE
RADIATOR
COMPRESSOR
Figure 1-7. Heating Cycle Flow Diagram
(GR60 Shown)
inside the bus. Engine coolant (glycol solution) is
circulated through the heating circuit by the engine and
Heating circuit (Figure 1-7) components furnished by
Carrier Transicold include the integral evaporator coil
an auxiliary boost water pump. When the heat valve
heater cores and a solenoid operated heat valve.
solenoid is energized, the valve will open to allow
engine coolant to flow through the heater coil. The valve
Components furnished by the bus manufacturer include
auxiliary heater and boost water pump. The controller
is normally closed so that if a failure occurs, the system
automatically controls the heat valve during the heating
will be able to cool.
and reheat modes to maintain required temperatures
1.9 HEATING CYCLE
T--295
1-8
1.10 RELAY BOARD
CB 11
K3
CB 1
CB 5
K7
K15
K16
D2 D6
K4
K8
K6
D14 D17
CB 4
K11
K10
K20
K19
K13
K12 D85
CB 9
D26 D30
K18
JP4
K5
CF1 CF2
D38 D41
CB 10
4 5 6
2 3
1
CB 3
CB 8
JP3
K2
CB 6
EF1 EF2
4 5
2 3
1
CB 12
CB 2
2 3
1
EF3 EF4
EF6
EF5
CF6
CF3 CF4
K24
D57
D54
K17
K9
CB 7
JP5
K1
K14
3 4
1 2
CB 13
JP6
1.10.1 Permanent Magnet Motors with 2 speed switching from series to parallel connection (Option 1)
D63
D60
D72
D66
D51
D69
CF5
JP1
K22
K21
K23
JP2
Figure 1-8 Relay Board (Option 1)
low speed.
a. Relays
K1 Energizes evaporator fans 1 & 2 in high speed
K12 Connects the negative side of condenser fan
or evaporator fans 1,2,3 & 4 in low speed.
5 to ground in high speed. Connects the
K2 Energizes evaporator fans 3 & 4 in high speed
negative side of condenser fan 5 to
(not energized in low speed).
the positive side of condenser fan 6 in
K3 Energizes evaporator fan 5 in high speed or
low speed.
evaporator fans 5 & 6 in low speed.
K13 Energizes the A/C clutch.
K4 Energizes evaporator fan 6 in high speed (not
K14 Energizes unloader 1.
energized in low speed).
K15 Energizes unloader 2.
K5 Connects the negative side of evaporator fans
K16 Energizes the fresh air damper.
1 & 2 to ground in high speed. Connects the
K17 Energizes the heat valve.
negative side of evaporator fans 1 & 2 to
K18 Energizes the fault light output.
positive side of evaporator fans 3 & 4 in
K19 Energizes the Boost Pump.
low speed
K20 Energizes the spare output.
K6 Connects the negative side of evaporator fan
K21 Is energized by the logic board to turn the
5 to ground in high speed. Connects the
evaporator fans on high. The contacts of this
negative side of evaporator fan 5 to
relay energize the coils of relays K1, K2,
positive side of evaporator fan 6 in
K3 & K4.
low speed
K22
Is
energized by the logic board to turn the
K 7 Energizes condenser fans 1 & 2 in high speed
evaporator fans on low. The contacts of this
or condenser fans 1,2,3 & 4 in low speed
relay energize the coils of relays K1, K3,
K 8 Energizes condenser fans 3 & 4 in high speed
K5 & K6.
(not energized in low speed).
K23
Is
energized by the logic board to turn the
K 9 Energizes condenser fan 5 in high speed or
condenser fans on high. The contacts of this
condenser fans 5 & 6 in low speed.
relay energize the coils of relays K7, K8,
K10 Energizes condenser fan 6 in high speed
K9 & K10.
(not energized in low speed).
K24 Is energized by the logic board to turn the
K11 Connects the negative side of condenser fans
condenser fans on low. The contacts of this
1 & 2 to ground in high speed. Connects the
relay energize the coils of relays K7, K9,
negative side of condenser fans 1 & 2 to
K11 & K12.
the positive side of condenser fans 3 & 4 in
1-9
T--295
b. Thermal Circuit Breakers
CB 1 Evaporator Fan #1. 15 Amp.
CB 2 Evaporator Fan #2. 15 Amp.
CB 3 Evaporator Fan #3. 15 Amp.
CB 4 Evaporator Fan #4. 15 Amp.
CB 5 Evaporator Fan #5. 15 Amp.
CB 6 Evaporator Fan #6. 15 Amp.
CB 7 Condenser Fan #1.
15 Amp.
CB 8 Condenser Fan #2.
15 Amp.
CB 9 Condenser Fan #3.
15 Amp.
CB10 Condenser Fan #4.
15 Amp.
CB11 Condenser Fan #5.
15 Amp.
CB12 Condenser Fan #6.
15 Amp.
CB13 A/C clutch, Unloaders 1&2,
Fresh Air Damper, Heat Valve,
Fault Output and Spare
output.
15 Amp
JP6 Unloaders 1 & 2.
d. LEDS
D 2 Relay K1 output active (evaporator fans 1,2,3 &
4 energized)
D 6 Will be brightly lit if evaporator fans 1, 2, 3 & 4
are on high. Will be at half intensity of they are on low.
D14 Relay K3 output active (evaporator fans 5 & 6
energized).
D17 .Will be brightly lit if evaporator fans 5 &6 are
on high. Will be at half intensity of they are on low.
D26 Relay K7 output active (condenser fans 1, 2, 3
& 4 energized).
D30 Will be brightly lit if condenser fans 1, 2, 3 & 4
are on high. Will be at half intensity of they are on low.
D38 Relay K9 output active (condenser fans 5 & 6
energized).
D41 Will be brightly lit if condenser fans 5 &6 are on
high. Will be at half intensity of they are on low.
D51 A/C clutch output active.
D54 Unloader 1 output active.
D57 Unloader 2 output active.
D60 Fresh air output active.
D63 Heat valve output active.
D66 Fault output active.
D69 Boost pump output active.
D72 Spare output active.
c. Connectors
EF1-EF6 Evaporator fans.
CF1-CF4 Condenser fans.
JP1 External evaporator & condenser fan
thermal overload connections.
JP2 Logic board connector.
JP3 Boost pump.
JP4 A/C clutch, fault output, compressor high
pressure switch.
JP5 Spare output, fresh air output, heat valve.
T--295
1-10
JP6
1.10.2 Electronically Communtated DC Motors with 2--speed Evaporator Input Signal (Option 2)
CB 11
CB 1
K5
K3
K7
CB 5
CB 7
K11
K15
K16
K17
K18
K19
K20
K13
K9
JP5
K1
K14
EF1 EF2
CB 4
EF6
JP4
CF1 CF2
D26 D30 CB 10
EF HIGH SIGNAL
EF5
D38 D41
CF6
CF3 CF4
K24
CF HIGH SIGNAL
D57
D54
D63
D60
D72
D66
D51
D69
2 3
1
EF3 EF4
D14D17
CB 9
4 5 6
2 3
1
D81
D85
K10
K8
K4
CB 3
JP3
K2
D2 D6
CB 8
CB 6
4 5
2 3
1
CB 12
CB 2
3 4
1 2
CB 13
CF5
JP1
K22
K21
K23
JP2
Figure 1-9 Relay Board (Option 2)
a Relays
K23 or K24 Is energized by the logic board to
K1 Energizes evaporator fans 1 & 2
turn the condenser fans on high. The contacts
K2 Energizes evaporator fans 3 & 4.
of these relays energize the coils of relays K7,
K3 Energizes evaporator fan 5.
K8, K9 & K10.
K4 Energizes evaporator fan 6.
b Thermal Circuit Breakers
K5 Provides evaporator fan high output signal.
Refer to paragraph 1.10.1b.
(Motors are in low speed when K5
is de--energized)
c. Connectors
Refer to paragraph 1.10.1c.
K6 Not Used
EF HIGH SIGNAL Output to the evaporator fans
K 7 Energizes condenser fans 1 & 2.
to operate on high.
K 8 Energizes condenser fans 3 & 4.
CF HIGH SIGNAL Output to the condenser fans
K 9 Energizes condenser fan 5
to operate on high.
K10 Energizes condenser fan 6.
K13 Energizes the A/C clutch.
d. LEDS
K14 Energizes unloader 1.
Refer to paragraph 1.10.1d.
K15 Energizes unloader 2.
D81 Evaporator fans on high
K16 Energizes the fresh air damper.
D85 Condenser fans on high
K17 Energizes the heat .
K18 Energizes the fault light output.
K19 Energizes the Boost Pump.
K20 Energizes the spare output.
K21 or K22 Is energized by the logic board to
turn the evaporator fans on. The contacts
of these relays energize the coils of relays K1,
K2, K3 & K4.
1-11
T--295
1.11 LOGIC BOARD
J1
J2
J3
J4
Logic board power in.
Display interface.
Manual control inputs.
Interlock Inputs
(WTS, low side pressure switch etc.)
J5 Relay board interface.
J6 Sensor inputs (Thermistors, etc.).
J7 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
T--295
1-12
1.12 CONTROL PANEL (Diagnostic Module)
1
2
3
4
5
6
7
11
1.
2.
3.
4.
5.
6.
10
8
9
Display
DOWN Button -- decrease selection
UP Button -- increase selection
VENT (Only) Button
AUTO Button (Automatic Control)
COOLING (Only) Button
7.
8.
9.
10.
11.
HEAT (Only) Button
FAN SPEED Button
FRESH AIR Button
TEMPERATURE ( Inside / Outside)
Button
ON/OFF Button
Figure 1-11. Micromate Control Panel
1-13
T--295
SECTION 2
OPERATION
2.1 STARTING, STOPPING AND OPERATING
INSTRUCTIONS
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.
2.1.1 Power to Logic Board
Before starting, electrical power must be available from
the bus power supply. The system components receive
power from two sources:
a. 24 vdc power for the microprocessor electronics is
supplied through the bus multiplex module.
b. 24 vdc, 125 amp, power from a 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
5 To open or close the fresh air damper, press the
FRESH AIR button to illuminate the indicator light
and bring the damper to the desired position.
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 2.4.
a. If the engine is not running, start the engine.
b. OEM SUPPLIED SWITCHES
Actual start sequence depends on the operating controls supplied. If only an ON/OFF switch is supplied,
place the switch in the ON position to start the system
in the automatic mode. If additional OEM switches
are supplied, refer to the following Micromate control description for operating instructions.
c. MICROMATE CONTROL PANEL
It is suggested the system be started in the automatic
mode.
1 The Micromate Control Panel Display (see
Figure 1-11) may be programmed to display the set
point temperature or return air temperature. To determine which display 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.
2 To start the system, press the I/O button to illuminate
the indicator light and signal the Logic Board to perform start up. 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 1-11) to illuminate the indicator light and
place the system in that mode of operation.
2-1
2.1.3 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.
2.1.4 Stopping
Placing the ON/OFF switch in the OFF position or
pressing the Micromate ON/OFF button will stop the
system operation by removing power to the Logic
Board.
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 4.20.3)
c. Check refrigerant charge. (Refer to section 4.8.1 )
d. Ensure that self-test has been successfully performed
and that there are no errors or alarms indicated. (Refer
to section 2.1.3.)
T--295
AUTO MODE REHEAT
COOL
HIGH SPEED
LOADED
3°F
HEAT MODE
AUTO MODE CYCLE
COOL
HIGH SPEED
LOADED
3°F
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
HIGH SPEED
4 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
2°F
1°F
SETPOINT
VENT
--1°F
SETPOINT
SETPOINT
REHEAT 100%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
VENT
--2°F
--1°F
HEAT
--3°F
--2°F
--2°F
HEAT
--3°F
--3°F
--4°F
HEAT
COOLING MODE
REHEAT
3°F
COOL
HIGH SPEED
LOADED
COOLING MODE
CYCLE
COOL
HIGH SPEED
LOADED
3°F
2°F
COOL
HIGH SPEED
4 CYLINDERS
2°F
COOL
HIGH SPEED
4 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
1°F
COOL
LOW SPEED
2 CYLINDERS
SETPOINT
SETPOINT
VENT
--1°F
--2°F
REHEAT 100%
DUTY CYCLE
LOW SPEED
4 CYLINDERS
--1°F
--2°F
Figure 2-1 Capacity Control Diagram
T--295
2-2
2.3 MODES OF OPERATION
2.3.4 Boost Pump
The system is operated by a Carrier Transicold
Micromax microprocessor controller which consists of
a logic board (Figure 1-10), relay board (Figure 1-8 or
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. Modes of
operation include Cooling, Heat and Vent. Refer
toFigure 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 setpoints, On falling temperature,
changes occur when temperatures falls below Logic
Board set point. 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 grille.
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 bus 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.
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.
When the unit is in heat the boost pump relay is
energized, providing 24 VDC to activate the boost
pump.
2.3.5 Vent Mode
In the vent mode the evaporator fans are operated to
circulate air in the bus interior.
2.3.6 Fresh Air System
The fresh air damper is opened to allow entrance of
ambient air into the air entering the evaporator coil. The
damper is operated by the controller to open when return
air temperature is within +/--5F (+/--2.8C) of set point.
2.3.7 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
05K (GR45) has two banks of two cylinders each while
the model 05G compressor (GR60) has three banks of
two cylinders each. Energizing a valve de-activates a
bank of cylinders. The 05K right cylinder bank (looking
at the pump end) and the outboard cylinder banks of the
05G are equipped with unloader valves (UV1 and, for
the 05G, UV2), each controlling two cylinders; this
allows the 05K to be operated with two or four cylinders
and the 05G to be operated with two, four or six
cylinders.
Whenever the compressor is started, the unloaders are
energized for thirty seconds to reduce starting torque.
After thirty seconds, unloaders may be de-energized.
Any subsequent changes between energizing and
de-energizing the unloaders for temperature control
must be staged with a thirty second delay. Once an
unloader is energized for pressure control, it remains
energized for two seconds 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. Temperature Control
2.3.3 Heating Mode
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.
Heating will not start until the water temperature switch
(WTS) closes. The WTS is located on the block of the
vehicle and is provided by the OEM. It senses the engine
coolant temperature and closes on temperature rise at
105F . The switch prevents the circulation of cooler air
throughout the vehicle as the engine comes up to
temperature.
2-3
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
(GR60 only) at 66% capacity.
b. Suction Pressure
T--295
The unloaders are used to control suction pressure and
thereby prevent coil frosting:
1 Compressor Unloader UV1 Relay. When the suction
pressure decreases below 26 psig (1.77 bar), unloader UV1 is energized unloading a cylinder bank (two
cylinders); this output will remain energized until
the pressure increases to above 34 psig (2.31 bar).
2 Compressor Unloader UV2 Relay. When suction
pressure decreases below 23 psig (1.56 bar) [on a
GR60], unloader UV2 is energized unloading the
second compressor cylinder bank; this output will
remain energized until the pressure increases to
above 31 psig (2.11 bar).
c. Discharge Pressure
Discharge pressure is also controlled by the unloaders:
1 Compressor Unloader UV1 Relay. When the discharge pressure increases above 275 psig (18.71
bar), unloader UV1 is energized; this output will remain energized until the pressure decreases below
220 psig (14.97 bar). Staging is ignored during discharge pressure override.
2 Compressor Unloader UV2 Relay. When the discharge pressure increases above 285 psig (19.39
bar),unloader UV2 is energized; this output will remain energized until the pressure decreases below
225 psig(15.31 bar).
2.3.8 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 form 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
2.3.10 Compressor Clutch Control
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.
The clutch coil is prevented from engagement when the
ambient temperature is below 45F (7.2C).
The clutch coil will be de-energized if the discharge
pressure rises to the 300 psig (20.41 bar) cutout setting
of the compressor mounted high pressure switch. The
clutch coil will energize when the discharge pressure
falls to 200 psig (13.61 bar).
The clutch coil will be de-energized if the suction
pressure decreases below 10 psig (0.68 bar).
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 2.4.3 for instructions on reading parameter
codes.
2.4
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. On systems with OEM supplied operating
switches, a Micromate may be connected as a service
tool using a special harness. The following instructions
supplement those provided in paragraph 2.1.2. Once a
Micromate is connected as a service tool, the following
instructions are applicable.
2.4.1 Connecting
2.3.9 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 225 psig (15.31 bar). The fans will
remain in high speed until discharge pressure decreases
below 190 psig (12.93 bar). The fans will also be
T--295
activated if a high pressure alarm has been activated and
operation has not been locked out (refer to Table 3-3).
2-4
Connect the Micromate harness to the service port
located in the return air section of the A/C system. When
the Micromate is connected, the panel lights will be
energized and the currently stored setpoint will be
displayed. If any alarm is active, the reading will be
A##, where A indicates that the alarm is active and ##
indicates the alarm number.
2.4.2 Control
2.4.4 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 2-3. 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.
NOTE
1
2
This procedure should be performed by an
HVAC technician who has been trained on
Carrier Model GR system design. Control
configuration is preset by the manufacturer
and resetting of the parameters should not
be required. It is recommended that Carrier
Service or Engineering is contacted before
any control configuration is changed.
Carrier can not be responsible for failures or
damage resulting from unauthorized
changes.
2.4.5 Test Mode
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.
a. Turn the A/C main power switch (located in the driver’s area) to OFF.
b. Connect the Micromate to the service port located in
the return air section.
c. Unplug the logic board connector J3.
d. Turn the A/C main power switch back to the ON position.
e. Activate the system by pressing the 1/0 key on the
Micromate panel.
NOTE
Be sure to reconnect J3 when testing is completed or the system will fail to operate when
the Micromate is disconnected.
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 2-2.
d. To terminate testing, press the I/0 key.
Table 2-2. Controller Test List
OUTPUT
STATE
TEST
NOTE
When modifying the setpoint temperature for
diagnostic purposes, be sure to reset the setpoint when testing is complete.
2.4.3 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.
2-5
T00
T01
T02
T03
T04
T05
T06
T07
T08
T09
T10
T11
T12
All Relays
Evaporator High
Evaporator Low
Condenser High
Condenser Low
Compressor
Unloader Valve 1
Unloader Valve 2
Fresh Air Damper
Heat
Fault
Boost
Spare/Motor Input
Off
On
On
On
On
On
On
On
On
On
On
On
On
T--295
Table 2-3. 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
This value is the coil temperature measured by the evaporator temperature sensor. If the sensor is shorted it will display CL. If it is open circuited it will display OP.
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
Not used.
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
Not used.
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 1 degree 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 1 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 heat valve 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.
P15
Unloader/Heat Valve
Delay
This is the minimum time (in seconds) that the unloaders and heat 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.
T--295
2-6
Table 2-3. Parameter Codes -- Continued
Code
Code Name
Description
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.
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.
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
This is the value at which the freeze alarm will be activated. The default value
is 32F. This value can be modified between 20F and 40F in one degree increments by using the arrow keys
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.
P33
to
P34
Not Defined
Not used. These codes will show in software revision 1.9 and later.
2-7
T--295
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 MDST.
ER 5
Program Memory
Display program memory failure.
3.2 SYSTEM ALARMS
3.2.2 Activation
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
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. 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 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.
T-295
3.2.3 Alarm Queue
The alarm queue consist of 10 alarm locations. 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 TROUBLESHOOTING
General procedures for system troubleshooting are
provided in Table 3-3
3-1
Table 3-2 Alarm Codes
ALARM
NO.
TITLE
CAUSE
REMEDY
CONTROLLER
RESPONSE
A11
Coil Freeze
Coil temperature is
Check causes of coil
less than 32F and the freezing. (Refer to
compressor is operat- section 3.3.6)
ing.
An alarm will be generated and the system will
shutdown. The evaporator fans will remain running while the compressor is off.
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 4.21. 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
switch open or wiring
defective.
Check cause of low
suction pressure. (Refer to section 3.5.3)
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
3.3.3)
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.
3-2
All outputs except the
evaporator fans will be
de-energized.
T--295
Table 3-2 Alarm Codes -- Continued
TITLE
ALARM
NO
CAUSE
REMEDY
CONTROLLER
RESPONSE
A22
Breaker Trip Alarm
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, or cor- Alarm displayed and the
not reached full oper- rect pressure shutmotor fail output is enerating speed or a motor down.
gized.
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.
T-295
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.
3-3
Alarm will be generated.
Table 3-3 General System Troubleshooting Procedures
INDICATION/
TROUBLE
3.3.1 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
3.3.2 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
Heat valve stuck open
Check
See Table 1-2.
3.3.3
3.3.6
3.3.7
4.11
4.8
Open
1.6
Check
3.3.6
3.3.8
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
4.8.1
Check
Check
Clean
See Note.
See Table 1-2.
4.8
See Table 1-2.
Open
Check/Open
4.11
4.8
3.3.7
3.3.6
Replace
See Table 1-2.
3.3.3 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
3.3.4 Abnormal Noise Or Vibrations
Compressor
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
3-4
Check/Tighten
See Table 1-2.
SeeTable 1-2.
3.3.7
4.20.3
Check
Check/Adjust
Clean
T--295
Table 3-3 General System Troubleshooting Procedures -- Continued
INDICATION/
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
3.3.4 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
3.3.5 Control System Malfunction
Will not control
Sensor or transducer defective
Relay(s) defective
Microprocessor controller malfunction
Logic Board J3 connector unplugged
4.21 or 4.22
Check
Check
3.3.6 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(s) defective
Motor brushes defective
Evaporator fan loose or defective
Fan damaged
Return air filter dirty
Icing of coil
Fan relay(s) 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
1.6
Check
3.3.7 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
4.8
Check
4.6
Replace
Replace
4.19
4.19
4.19
Check
4.7
Replace
Replace
4.19
3.3.8 Heating Malfunction
Insufficient heating
No Heating
Continuous Heating
T-295
Dirty or plugged heater core
Coolant solenoid valve(s) malfunctioning or plugged
Low coolant level
Strainer(s) plugged
Hand valve(s) closed
Water pumps defective
Auxiliary Heater malfunctioning.
Coolant solenoid valve(s) malfunctioning or plugged
Controller malfunction
Pump(s) malfunctioning
Safety device open
Coolant solenoid valve stuck open
3-5
Clean
Check/Replace
Check
Clean
Open
Repair/Replace
Repair/Replace
Check/Replace
Replace
Repair/Replace
1.6
Replace
SECTION 4
SERVICE
WARNING
BE SURE TO OBSERVE WARNINGS LISTED IN THE SAFETY SUMMARY IN THE FRONT OF
THIS MANUAL BEFORE PERFORMING MAINTENANCE ON THE HVAC SYSTEM
NOTE
Following completion of all maintenance or service activities, the alarm queue should be cleared of any original alarms and any alarms generated during service. Refer to paragraph 3.2.1
4.1 MAINTENANCE SCHEDULE
SYSTEM
ON
REFERENCE
SECTION
SYSTEM
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
See above
None
4.6
4.11
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 OPENING TOP COVER
See above
None
Replace/Tighten
None
None
None
4.3 SUCTION AND DISCHARGE SERVICE VALVES
To open the top cover, push in on the latches and pull
forward as the cover is lifted . (See Figure 4-1.)
The suction and discharge service valves (Figure 4-2)
are provided with a double seat and a gauge port, 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 line to the
compressor and close off the gauge port. In normal
operation, the valve is backseated to allow full flow
through the valve. The valve should always be
backseated before removing the gauge port cap.
1
PUSH IN ON LATCHES
PULL & LIFT
Turning the valve stem clockwise (all the way forward)
will frontseat the valve to isolate the compressor line
and open the gauge port.
2
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 gauge
port is open to both the compressor and the line.
Figure 4-1. Opening Top Cover
4-1
T-295
e. Frontseat (clockwise) both manifold gauge hand
valves.
f. Turn the service valve connected to the discharge
gauge port toward frontseat (clockwise) approximately 1/4 to 1/2 turn.
g. Slowly turn the manifold discharge hand valve toward backseat (counterclockwise) approximately
one turn.
h. Tighten charging hose onto dummy fitting.
VALVE CAP
TO DISCHARGE OR
FROM SUCTION
LINE
SERVICE
PORT
PORT TO
COMPRESSOR
Service Valve
Frontseated
(clockwise)
VALVE
STEM
i. Slowly turn the manifold suction hand valve toward
backseat (counter--clockwise) to remove air from
line.
j. Tighten suction hose at the service valve port.
k. Frontseat (close) both manifold hand valves.
Service Valve
Backseated
(counterclockwise)
Figure 4-2.Suction or Discharge Service Valve
l. Turn the service valve connected to the suction gauge
port toward frontseat (clockwise) approximately 1/4
to 1/2 turn.
4.4 INSTALLING MANIFOLD GAUGE SET
A manifold gauge set (Figure 4-3) can be used to
determine system operating pressures, add charge,
equalize or evacuate the system.
Suction
Pressure
Gauge
4.5 PUMPING THE SYSTEM DOWN OR REMOVING THE REFRIGERANT CHARGE
NOTE
To avoid damage to the earth’s ozone layer, use
a refrigerant recovery system whenever removing refrigerant.
Discharge
Pressure
Gauge
4.5.1 System Pump Down For Low Side Repair
Hand Valve
(Backseated)
A.
B.
C.
A
C
B
To service or replace the filter--drier, thermostatic
expansion valve, suction line or evaporator coils, pump
the refrigerant to the condenser and receiver as follows:
a. Install manifold gauge set. Refer to Figure 4-4
Hand Valve
(Frontseated)
Connection to Low Side of System
Connection to High Side of System
Connection to Vacuum Pump, Refrigerant
Cylinder, Oil Container or Evacuation Line
b. Frontseat the filter--drier inlet service valve by turning clockwise. Disconnect suction pressure transducer and install a jumper on the compressor mounted
low pressure switch.
c. Start the system and run in cooling. Stop the unit
when suction reaches 10 ”/hg (25.4 cm/hg) vacuum.
Figure 4-3. Manifold Gauge Set
When the suction pressure hand valve is frontseated
(turned all the way in), the suction (low) pressure can be
read. When the discharge pressure hand valve is
frontseated, discharge (high) pressure can be read.
When both valves are open (turned counterclockwise),
high pressure vapor will flow into the low side. When
only the low pressure valve is open, the system can be
charged or evacuated. To install a manifold gauge set,
do the following (refer to Figure 4-4, Figure 4-5 or
Figure 4-6 as applicable).
d. Frontseat compressor suction service valve to trap refrigerant in the high side of the system between the
compressor suction service valve and the filter--drier
inlet valve. Wait 5 minutes to verify that system remains in a vacuum. If system pressure rises above
vacuum, open compressor suction service valve and
repeat steps c and d until system remains in vacuum.
e. Service or replace necessary components.
f. Leak check connections and replace filter--drier. Refer to paragraph 4.6.
g. Using refrigerant hoses designed for vacuum service,
evacuate and dehydrate the low side of the system by
connecting a vacuum pump to center connection of
manifold gauge set. Evacuate system to 500 microns.
Close off pump valve, isolate vacuum gauge and stop
pump. Wait 5 minutes to verify that vacuum holds.
h. Recharge low side to 20 to 30 psig (1.36 to 2.04 bar)
by admitting vapor from the refrigerant cylinder.
a. Remove the service valve stem caps and backseat
(counterclockwise) both valves. Remove the service
port caps.
b. Connect the discharge side hose tightly to the service
valve port.
c. Connect the suction side hose loosely to the other service valve port.
d. Loosen charging (center) hose at dummy fitting of
manifold set.
T-295
4-2
f. Check refrigerant level. Refer to paragraph 4.8.1. It
may be necessary to clear any alarms that have been
generated.
3
S D
4
3
5
S D
10
2
9
1
4
8
2
1
1. Filter-Drier Inlet
Service Valve
2. Thermostatic
Expansion Valve
3. Manifold Gauge
Set
4. Thermistor Vacuum
Gauge
7
6
5
7
5.
6.
7.
8.
9.
Vacuum Pump
Refrigerant Cylinder
Reclaimer
Filter-Drier
Liquid Solenoid
Valve
10. Filter-Drier Outlet
Service Valve
6
1. Discharge Service
Valve and Port
2. Suction Service
Valve and Port
3. Manifold Gauge
Set
4.
5.
6.
7.
Vacuum Pump
Reclaimer
Refrigerant Cylinder
Thermistor Vacuum
Gauge
Figure 4-4. Low Side Pump Down Connections
Figure 4-5. Compressor Service Connections
i. Re--connect suction pressure transducer and remove
low pressure switch jumper. If required, clear any
alarms that have been generated during this procedure.
4.5.3 Pump Down An Operable Compressor For
Repair
To service an operable compressor, pump the refrigerant
into the condenser coil and receiver as follows:
a. Install manifold gauge set. Refer to Figure 4-5.
b. Frontseat the compressor suction service valve by
turning clockwise.
c. Place a jumper on the low pressure switch. Start the
unit and run in cooling until 10 ”/hg (25.4 cm/hg) of
vacuum is reached. Shut the system down.
d. 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.
e. Service or replace components as required and leak
check the compressor.
f. Using refrigerant hoses designed for vacuum service,
connect a vacuum pump to center connection of manifold gauge set. Evacuate system to 500 microns.
Close off pump valve, isolate vacuum gauge and stop
pump. Wait 5 minutes to verify that vacuum holds.
g. Once vacuum is maintained, re--connect low pressure
switch, disconnect manifold gauge set and open compressor service valves.
h. Check refrigerant level. Refer to paragraph 4.8.1. It
may be necessary to clear any alarms that have been
generated.
j. Open service valves and check refrigerant level. Refer to paragraph 4.8.1.
4.5.2 Refrigerant Removal From An Inoperative
Compressor.
To remove the refrigerant from a compressor that is not
operational, do the following:
a. Attach a manifold gauge set as shown in Figure 4-5
and isolate the compressor by frontseating the suction
and discharge valves.
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 compressor.
d. Using refrigerant hoses designed for vacuum service,
connect a vacuum pump to center connection of manifold gauge set. Evacuate system to 500 microns.
Close off pump valve, isolate vacuum gauge and stop
pump. Wait 5 minutes to verify that vacuum holds.
e. Once vacuum is maintained, recharge low side to 20
to 30 psig (1.36 to 2.04 bar) by admitting vapor from
the refrigerant cylinder. Disconnect manifold gauge
set and backseat compressor service valves.
4-3
T-295
2
c. Add sufficient nitrogen to raise system pressure to
150 to 200 psig (10.21 to 13.61 bar).
d. Check for leaks. The recommended procedure for
finding leaks in a system is with an electronic leak detector. Testing joints with soapsuds is satisfactory
only for locating large leaks.
e. Remove test gas and replace filter--drier.
f. Evacuate and dehydrate the system. (Refer to paragraph 4.7.)
g. Charge the unit. (Refer to paragraph 4.8.)
h. Ensure that a Logic Board self-test has been performed and that there are no errors or alarms indicated. (Refer to paragraph 2.1.3.)
4
S D
3
1
5
4.7 EVACUATION AND DEHYDRATION
6
8
4.7.1 General
7
1. Suction Service
Valve and Port
2. Discharge Line
Service Port
3 Check Valve
4. Manifold Gauge
5.
6.
7.
8.
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.
Set
Vacuum Pump
Reclaimer
Refrigerant Cylinder
Thermistor Vacuum
Gauge
4.7.2 Preparation
NOTE
Using a compound gauge for determination of
vacuum level is not recommended because of
its inherent inaccuracy.
Figure 4-6. System Charge Removal Connections
4.5.4. Removing Entire System Charge
To remove the entire refrigerant charge, do the
following:
a. Connect a manifold gauge set to the system as shown
in Figure 4-6.
a. Evacuate and dehydrate only after pressure leak test.
(Refer to paragraph 4.6)
b. Essential tools to properly evacuate and dehydrate
any system include a good vacuum pump with a minimum of 5 cfm (8.5 m 3/hr) volume displacement,
(CTD P/N 07-00176-01), and a good vacuum indicator (available through Robinair Manufacturing,
Montpelier, Ohio, Part Number 14010).
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.
b. Connect a reclaimer to the center manifold gauge set
connection.
c. Recover refrigerant in accordance with reclaimer
manufacturers instructions.
4.6 REFRIGERANT LEAK CHECK
A refrigerant leak check should always be performed
after the system has been opened to replace or repair a
component.
4.7.3 Procedure for Evacuation and Dehydrating
System
To check for leaks in the refrigeration system, perform
the following procedure:
a. Remove refrigerant using a refrigerant recovery system. Refer to paragraph 4.5.4
b. The recommended method is connecting lines (3/8”
OD copper tubing or refrigerant hoses designed for
vacuum service) as shown in Figure 4-6.
c. Make sure vacuum pump valve is open.
d. Start vacuum pump. Slowly open valves halfway and
then open vacuum gauge valve.
e. Evacuate unit until vacuum gauge indicates 1500 microns Hg vacuum. Close gauge valve, vacuum pump
valve, and stop vacuum pump.
f. Break the vacuum with clean dry refrigerant. Use refrigerant that the unit calls for. Raise system pressure
to approximately 2 psig (0.14 bar).
NOTE
It must be emphasized that only the correct refrigerant should be used to pressurize the system. Use of any other refrigerant will contaminate the system, and require additional
evacuation.
a. Ensure the liquid line service and solenoid valves are
open.
b. If system is without refrigerant, charge system with
refrigerant vapor to build up pressure between 20 to
30 psig (1.36 to 2.04 bar).
T-295
4-4
4.8.3 Adding Partial Charge
g. Remove refrigerant using a refrigerant recovery system.
a. Install manifold gauge set at the compressor suction
service valve and service port above the discharge
line check valve. See figure Figure 4-6.
b. Place appropriate refrigerant cylinder on scales. Prepare to charge vapor refrigerant by connecting charging hose from container to center connection on
gauge manifold . Purge air from hoses.
c. Run unit in cool mode for 15 minutes. With suction
service valve midseated open cylinder valve and add
vapor charge until refrigerant level appears in the
lower receiver sight glass. Under the above conditions, the system is properly charged when the refrigerant liquid level is at 1/2 to 3/4 of the lower receiver
sight glass. If it is not at the proper level, add or remove refrigerant to bring it to the proper level. Refrigerant level should not appear in the upper sight
glass, as this would indicate an overcharge.
d. Backseat suction service valve. Close vapor valve on
refrigerant drum and note weight. Remove manifold
gauge set and replace all valve caps.
h. Start vacuum pump and open all valves. Dehydrate
unit to 500 microns Hg vacuum.
i. Close off pump valve, and stop pump. Wait five minutes to see if vacuum holds.
j. Charge system. Refer to paragraph 4.8.2
4.8 ADDING REFRIGERANT TO SYSTEM
4.8.1 Checking Refrigerant Charge
The following conditions must be met to accurately
check the refrigerant charge.
a. Coach engine operating at high idle.
b. Unit operating in cool mode for 15 minutes.
c. Head pressure at least 150 psig (10.21 bar). (It may be
necessary to block condenser air flow to raise head
pressure.)
4.9 CHECKING FOR NONCONDENSIBLES
d. Under the above conditions, the system is properly
charged when the refrigerant liquid level is at 1/2 to
3/4 of the lower receiver sight glass. If it is not at the
proper level, add or remove refrigerant to bring it to
the proper level. Refrigerant level should not appear
in the upper sight glass, as this would indicate an
overcharge.
To check for noncondensibles, proceed as follows:
a. Stabilize system to equalize pressure between the
suction and discharge side of the system.
b. Check temperature at the condenser and receiver.
c. Check pressure at the compressor discharge service
valve.
d. Check saturation pressure as it corresponds to the
condenser/receiver temperature using the Temperature-Pressure Chart, Table 4-4.
e. If gauge reading is 3 psig (0.20 bar) or more than the
saturation pressure in step d, noncondensibles are
present.
f. Remove refrigerant using a refrigerant recovery system.
g. Evacuate and dehydrate the system. (Refer to paragraph 4.7.)
h. Charge the unit. (Refer to paragraph 4.8.2.)
4.8.2 Adding Full Charge
a. Install manifold gauge set at the compressor suction
service valve and service port above the discharge
line check valve. See figure Figure 4-6.
b. Evacuate and dehydrate system. (Refer to paragraph
4.7)
c. Place appropriate refrigerant cylinder on scales. Prepare to charge liquid refrigerant by connect charging
hose from container to center connection on gage
manifold . Purge air from hoses.
d. Note weight of refrigerant and cylinder.
4.10 CHECKING AND REPLACING HIGH PRESSURE SWITCH
e. Open cylinder valve, backseat discharge valve on
gauge manifold and allow liquid refrigerant to flow
into the high side of the system
WARNING
DO NOT USE A NITROGEN CYLINDER
WITHOUT A PRESSURE REGULATOR
f. When correct charge has been added, refer to paragraph 1.3, close cylinder valve and frontseat manifold discharge valve. At this point, the high side of
the system has been charged but the low side is still in
a vacuum because the liquid line solenoid is normally
closed.
WARNING
DO NOT USE OXYGEN IN OR NEAR A
REFRIGERATION SYSTEM AS AN EXPLOSION MAY OCCUR.
g. Prepare the cylinder as required to allow vapor charging. Backseat the manifold suction valve and charge
vapor to build 20 to 30 psig (1.36 to 2.04 bar) pressure on the manifold suction gauge. Close cylinder
valve and frontseat suction manifold set.
a. Disconnect wiring and remove switch from unit. All
units are equipped with a schrader valve at the high
pressure switch connection.
b. Connect switch to a cylinder of dry nitrogen. (See
Figure 4-7.)
h. Check charge level in accordance with the procedures
of paragraph 4.8.1.
4-5
T-295
4.11.2 To Replace Filter--Drier
1
a. Perform a low side pump down. Refer to paragraph
4.5.1.
4
5
2
b. Turn the driver’s A/C switch to “OFF” position.
6
c. Frontseat the filter--drier outlet service valve and
place a new filter-drier near the unit for immediate
installation.
3
1.
2.
3.
4.
5.
6.
WARNING
THE FILTER-DRIER MAY CONTAIN
LIQUID REFRIGERANT. SLOWLY
LOOSEN THE FLARE NUTS AND AVOID
CONTACT WITH EXPOSED SKIN OR
EYES.
Cylinder Valve and Gauge
Pressure Regulator
Nitrogen Cylinder
Pressure Gauge (0 to 400 psig = 0 to 27.22 bar)
Bleed-Off Valve
1/4 inch Connection
d. Using two open end wrenches, slowly crack open the
flare nuts on each side of the filter-drier. Remove the
filter-drier.
Figure 4-7. Checking High Pressure Switch
e. Remove seal caps from the new filter-drier. Apply a
light coat of compressor oil to the flares.
c. Connect an ohmmeter across switch terminals.
f. Assemble the new filter-drier to lines ensuring that
the arrow on the body of the filter-drier points in the
direction of the refrigerant flow (refrigerant flows
from the receiver to the evaporator). Finger tighten
flare nuts.
d. Set nitrogen pressure regulator higher than switch
cutout setting. (refer to paragraph 1.3.)
e. Close cylinder valve and open bleed--off valve. Open
cylinder valve and slowly close bleed--off valve. The
switch should open, (no continuity) with in required
cut out tolerance.
g. Tighten filter-drier flare nuts using two open end
wrenches.
f. Close cylinder valve and release pressure through the
bleed-off valve. As pressure drops, switch should
close, (continuity) within required cut in tolerance.
h. Evacuate the filter--drier and lines by connecting a
vacuum pump as shown in Figure 4-4. Evacuate to
500 microns.
g. Replace or re--install switch (as required) and reconnect wiring.
i. Backseat (fully close) both service valve ports and replace valve caps.
4.11 FILTER-DRIER
j. Test filter-drier for leaks.
k. Check refrigerant level.
4.12 CONDENSER COIL REPLACEMENT
1
1.
2.
3.
4.
2
3
4
Filter-Drier Inlet
Service Valve
Valve Service Port
Flare Nut
Filter-Drier
3
5
6.
5
2
a. Place the driver’s A/C switch in the OFF position and
tag to prevent unintentional starting.
6
b. Remove the refrigerant charge. Refer to paragraph
4.5.4.
Liquid Line
Solenoid Valve
Filter-Drier Outlet
Service Valve
c. Remove the connection access covers to gain access
to the mounting screws. Remove the mounting
screws in the connection compartment and at the rear
of the unit next to the receiver supports.
d. Remove the filter--drier mounting screws and remove
the filter--drier. Disconnect the discharge hose.
Figure 4-8. Filter--Drier Removal
4.11.1 To Check Filter--Drier
e. Begin to lift the coil assembly at the left rear. Lift to
clear the service valve then push to the right to clear
the precharge valve. Continue to lift towards the front
to clear the sight glasses and remove from the unit.
The filter--drier (see Figure 4-8) must be changed if the
receiver mounted moisture indicator shows high
moisture content or the drier is partially restricted.
Check for a restriction by feeling the inlet and outlet
lines of the filter--drier. If the outlet side feels cooler than
the inlet side, then the filter--drier should be changed
T-295
f. To install the coil assembly, reverse the removal procedure.
4-6
4.13 EVAPORATOR COIL REPLACEMENT
b. Place main battery disconnect switch in OFF position
and lock.
c. Disconnect wire leads to coil.
d. Remove coil retaining screw and nameplate.
e. Lift burned-out coil from enclosing tube and replace.
f. Connect wire leads and test operation.
a. If refrigerant remains in the system, perform a low
side pump down to remove refrigerant from the evaporator coils.
CAUTION
If unit was recently operated, be careful of
remaining hot coolant in the hoses when disassembling.
4.14.2 Internal Part Replacement
a. Place main battery disconnect switch in OFF position
and lock.
b. Open the vent fitting at the top of the outlet header of
the heater coil.
c. Drain coil by opening the drain-cock on the inlet tube.
d. Disassemble valve and replace defective parts.
e. Assemble valve, refill and bleed coolant lines.
b. Remove fresh air intake.
c. Drain heater coil by removing the required coolant
from the engine cooling system.
d. Remove 12 mounting screws, 4 each at the receiver
support, at the front of the unit and at the return air
opening.
e. Remove the electronic board and harness.
f. Remove the filter--drier.
g. Disconnect suction line hose and lift coil out of unit.
h. To install the coil assembly, reverse the removal procedure.
4.14.3 Replace Entire Valve
a. Place main battery disconnect switch in OFF position
and lock.
b. Drain coolant from lines as previously described and
disconnect hoses to valve .
c. Disconnect wire leads to coil.
d. Remove valve assembly from bracket.
e. Install new valve and re-connect hoses. It is not necessary to disassemble the valve when installing.
f. Refill and bleed coolant lines.
g. Connect wire leads and test operation.
1
2
4.14 SERVICING THE HEAT VALVE
The heat valve (Figure 4-9) requires no maintenance
unless a malfunction to the internal parts or coil occurs.
This may be caused by foreign material such as: dirt,
scale, or sludge in the coolant system, or improper
voltage to the coil.
There are only three possible valve malfunctions: coil
burnout, failure to open, or failure to close.
Coil burnout may be caused by the following:
3
1 Improper voltage.
2 Continuous over-voltage, more than 10% or Undervoltage of more than 15%.
3. Incomplete magnetic circuit due to the omission of
the coil housing or plunger.
4
1 Coil burned out or an open circuit to coil connections.
5
6
7
8
9
2 Improper voltage.
3 Torn diaphragm.
4 Defective plunger or deformed valve body assembly.
10
4. Mechanical interference with movement of plunger
which may be caused by a deformed enclosing tube.
Failure to open may be caused by the following:
Failure to close may be caused by the following:
1. Coil Retaining Screw
2. Nameplate
3. Coil Housing
Assembly
4. Enclosing Tube &
Bonnet Assembly
1 Defective plunger or deformed valve body assembly.
2 Foreign material in the valve.
3 Torn diaphragm.
4.14.1 Coil Replacement
a. It is not necessary to drain the coolant from the system.
5.
6.
7.
8.
9.
10.
Kick-Off Spring
Plunger
Closing Spring
Diaphragm
O-Ring
Valve Body
Figure 4-9. Heat Valve
4-7
T-295
4.15 SERVICING THE LIQUID LINE SOLENOID
VALVE
1
2
The Liquid line solenoid valve (Figure 4-10) is very
similar to the heat valve. It requires no maintenance
unless a malfunction to the internal parts or coil occurs.
This may be caused by foreign material such as: dirt,
scale, or sludge in the refrigeration system, or improper
voltage to the coil.
3
There are only three possible valve malfunctions: coil
burnout, failure to open, or failure to close.
4
5
Coil burnout may be caused by the following:
1 Improper voltage.
6
2 Continuous over-voltage, more than 10% or undervoltage of more than 15%.
7
8
3 Incomplete magnet circuit due to the omission of the
coil hosing or plunger.
1. Snap Cap
2. Coil Assembly
3. Enclosing Tube
Assembly
4. Plunger Assembly
4 Mechanical interface with movement of plunger
which may be caused by a deformed enclosing tube.
Failure to open may be caused by the following:
1 Coil burned out or an open circuit to coil connections.
5.
6.
7.
8.
Gasket
Piston Assembly
Body
Bracket Adapter
Figure 4-10. Liquid Line Solenoid Valve
4.15.3.Replace Entire Valve
2 Improper voltage.
a. Perform a low side pump down, remove coil and
plunger assembly and un--braze valve from lines.
b. Remove valve assembly from bracket.
c. Disconnect wire leads to coil.
d. Disassemble new valve, to protect internal parts, and
solder to lines.
e. Assemble and leak check valve.
f. Evacuate low side and re--open system.
g. Connect wire leads and test operation.
3 Defective plunger or deformed valve body assembly.
Failure to close may be caused by the following:
1 Defective plunger or deformed valve body assembly.
2 Foreign material in the valve.
4.15.1 Coil Replacement
a. It is not necessary to remove the refrigerant charge
from the system.
b. .Place main battery disconnect switch in OFF position and lock.
4.16 CONDENSER FAN/MOTOR ASSEMBLY
c. Disconnect wire leads to coil.
a. Place main battery disconnect switch in OFF position
and lock.
b. Unlatch motor draw latches. See Figure 4-11.
c. Disconnect motor wire harness and lift motor out of
unit.
4.16.1 Removal
d. Remove coil retaining clip and nameplate.
e. Lift burned-out coil from enclosing tube and replace.
f. Connect wire leads and test operation
4
4.15.2 Internal Part Replacement
3
a. Place main battery disconnect switch in OFF position
and lock.
2
b. Perform a low side pump down. Refer to paragraph
4.5.1.
1
c. Slowly loosen enclosing tube assembly to bleed any
remaining pressure from the valve. Disassemble
valve and replace defective parts.
5
1. Motor Support
2. Draw Latch
3. Fan/Motor Assembly
d. Assemble valve and leak check.
e. Evacuate low side and re--open system.
T-295
4
4. Motor
5. Brush
Figure 4-11. Condenser Fan/Motor Assembly
4-8
4.16.2 Inspection And Cleaning
d. To reassemble, reverse procedure.
a. At regular maintenance periods, remove brush covers, examine and clean motor interior.
4.18 REPLACING RETURN AIR FILTERS
The return air filters are located behind the return air
grill, inside the vehicle.
The filters should be checked for cleanliness
periodically depending on operating conditions. A dirty
filter will restrict air flow over the evaporator coil which
may cause insufficient cooling or heating and possible
frost buildup on the coil. To remove the filters, do the
following.
a. Place main battery disconnect switch in OFF position
and lock.
b. Remove the return air grille.
c. Loosen filter retaining clips and remove the filter
from the grille.
d. Reverse procedure to install new filters.
b. Place main battery disconnect switch in OFF position
and lock.
c. Remove all foreign material. such as dirt and carbon
dust with dry moderately compressed air. Clean by
suction if possible to avoid blowing foreign matter
into the motor.
d. Confirm free movement of brushes to prevent binding.
e. Examine brush wear and general condition. If broken, cracked chipped or worn to 1/3 the original
length, replace. Refer to paragraph 4.16.3.
f. Examine the condition of the brush springs. A discolored spring is a sign of overheating which may weaken the spring. If discolored, replace.
g. Observe condition of communtator and armature
coils
4.19 THERMOSTATIC EXPANSION VALVE
The thermostat expansion valve (Figure 4-13) 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
control of refrigerant flow to match the evaporator load
and (b) prevention of liquid refrigerant entering the
compressor. Unless the valve is defective, it seldom
requires any maintenance.
4.16.3 Brush Replacement
a. Place main battery disconnect switch in OFF position
and lock.
b. Remove condenser motor, refer to paragraph 4.16.1.
c. Remove brush covers, remove and inspect brush assemblies. Replace if required.
1
d. Replace brush covers and reinstall condenser motor.
e. To reassemble, reverse the above procedure. Ensure
motor is properly seated in support.
f. Verify the proper operation of motor.
2
3
4
5
4
6
MOUNTING
CLIP
7
1. Power Head
Assembly
2. Equalizer Connection
3. Bulb
4.
5.
6.
7.
Gasket
Cage Assembly
Body Flange
Cap screw
Figure 4-13. Thermostatic Expansion Valve
4.19.1 Valve Replacement
Figure 4-12. Evaporator Fan Removal
a. Pump down low side of the unit. (Refer to paragraph
4.5.1)
b. Remove insulation from expansion valve bulb. (See
Figure 4-13 and Figure 4-14.)
c. Loosen retaining straps holding bulb to suction line
and detach bulb from the suction line.
d. Loosen flare nuts on equalizer line and disconnect
equalizer line from the expansion valve.
4.17 REPLACING EVAPORATOR FAN
a. Place main battery disconnect switch in OFF position
and lock.
b. Disconnect wire leads to the motor. Mark leads for
proper reassembly.
c. Remove motor by lifting the mounting clip (see
Figure 4-12) up and out. Slide motor from unit.
4-9
T-295
e. Remove capscrews and lift off power head and cage
assemblies and gaskets.
c. Loosen one TXV bulb clamp and make sure area under clamp is clean.
f. Check, clean and remove any foreign material from
the valve body, valve seat and mating surfaces. If required, replace valve body.
d. Place temperature thermocouple in contact with the
suction tube and parallel to the TXV bulb, and then
secure loosened clamp making sure both bulb and
thermocouple are firmly secured to suction line.
(SeeFigure 4-14.) Reinstall insulation around the
bulb.
NOTE
Do not adjust the new replacement expansion
valve. Valves are preset at the factory.
e. Connect an accurate low pressure gauge to the low
pressure port (9, Figure 1-6)
f. Close top cover being careful to route thermocouple
sensing wire and gauge hose outside the unit.
g. Using new gaskets, install new cage and power head
assemblies.
g. Start bus and run on fast idle until unit has stabilized,
about 20 to 30 minutes.
h. Leak check the new valve and evacuate and dehydrate
low side. (Refer to paragraph 4.7.)
NOTE
When conducting this test, the suction pressure
must be at least 6 psig (0.41 bar) below the expansion valve maximum operating pressure
(MOP). Refer to paragraph 1.3 for MOP.
i. 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. Strap
thermal bulb to suction line. Ensure that retaining
straps are tight and renew insulation.
j. Fasten equalizer line to the expansion valve.
h. From the temperature/pressure chart (Table 4-4), determine the saturation temperature corresponding to
the evaporator outlet pressure.
k. Open filter-drier inlet service valve and compressor
service valves.
l. Run the coach for approximately 30 minutes on fast
idle.
i. Note the temperature of the suction gas at the expansion valve bulb. Subtract the saturation temperature
from this temperature. The difference is the superheat
of the suction gas.
m.Check refrigerant level. (Refer to paragraph 4.8.1)
n. Check superheat. (Refer to paragraph 4.19.2.)
j. The superheat may cycle from a low to high reading.
Monitor the superheat taking readings every 3--5
minutes for a total of 5--6 readings. Calculate the superheats, add the readings and divide by the number
of readings taken to determine average superheat.
The superheat should be 10F to 12F.
4.19.2 Superheat Measurement
NOTE
All readings must be taken from the TXV bulb
location and out of the direct air stream.
k. If superheat is not within tolerance, replace the valve.
4.20 COMPRESSOR MAINTENANCE
4.20.1 Removing the Compressor
3
If compressor is inoperative and the unit still has
refrigerant pressure, isolate the compressor and remove
the refrigerant. Refer to paragraph 4.5.2. If compressor
is operative, perform a pump down. Refer to paragraph
4.5.3.
4
2
5
1
1. Suction Line
(section view)
2. TXV Bulb Clamp
3. Nut & Bolt (clamp)
a. Place main battery disconnect switch in OFF position
and lock.
4. Thermocouple
5. TXV Bulb (Shown
in the 4’clock
position)
b. Loosen bolts at suction and discharge service valve
flanges and break seal to be sure pressure is released.
remove bolts.
c. Tag and disconnect wiring to the high pressure and
low pressure switch, unloaders and clutch.
Figure 4-14.Thermostatic Expansion Valve Bulb
and Thermocouple
d. Remove four bolts holding compressor to base
a. Open top cover. Refer to paragraph 4.2.
e. Attach sling or other device to the compressor and remove compressor from the coach through the rear access door.
b. Remove Presstite insulation from expansion valve
bulb and suction line.
T-295
4-10
ate compressor to 500 microns. Front seat both manifold valves to isolate the pump.
l. Start unit and check refrigerant level (refer to paragraph 4.8.1).
m.Check compressor oil level (refer to paragraph
4.20.3). Add or remove oil if necessary.
n. Check compressor unloader operation.
o. Remove manifold gauge set.
NOTES
1
Service replacement compressors are sold
without service valves. Valve pads are
installed in their place. The optional
unloaders are not supplied, as the cylinder
heads are shipped with plugs. Customer
should retain the original unloader valves
for use on the replacement compressor.
2
The piston plug that is removed from the
replacement compressor head must be
installed in the failed compressor if
returning for warranty or core credit.
3
4
4.20.2 Transferring Compressor Clutch
To remove a clutch (see Figure 4-16) from a compressor
and install on a replacement compressor, do the
following:
Do not interchange allen-head capscrews
that mount the piston plug and unloader,
they are not interchangeable.
1
2
3
Check oil level in service replacement
compressor. (Refer to paragraphs 1.3 and
4.20.3.)
4
f. Remove the three socket head capscrews from the
cylinder head(s) that have unloader valves installed.
See Figure 4-15. Remove the unloader valve and bypass piston assembly, keeping the same capscrews
with the assembly. 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 bypass piston plug must be
removed.
1.
2.
3.
4.
Compressor (typical)
Seal Cover
Coil
Rotor
5.
6.
7
8.
5
6
7
8
Rotor Nut
Armature
Spacer Nuts
Snap Ring
Figure 4-16. Compressor Clutch
GASKET
COMPRESSOR
HEAD
SPRING
FLANGE
COVER
a. Using a wrench on the armature flats to keep it from
turning, remove the special bolt holding it to the
shaft.
b. Using special tool (CTD Part Number 07--00242
--01), remove the rotor nut and rotor. Retain original
key.
c. Noting the position of the wire, remove the three bolts
holding the coil to the compressor.
d. Remove every other bolt from the seal cover of the
new compressor in the same manner as the original
compressor. Mount the coil assembly with the wire in
the same orientation as it was mounted on the original
compressor. Tighten the mounting bolts to 45 lbs/ft
(6.2 mkg).
e. Mount rotor on shaft with rotor nut. Be sure pulley
turns freely without binding.
f. Install armature on shaft using original key and tighten mounting bolt to 20 ft/lbs (2.8 mkg).
g. Perform a check of the air gap between the inside face
of the armature and the mating face of the rotor. The
air gap should be measured with a minimum of 50
psig (3.4 bar) in the crankcase. A preliminary check
may be performed before the crankcase is pressurized
but a final check must be performed before the clutch
is operated. The gap should be between 0.016 and
CAPSCREWS
BYPASS
PISTON
PLUG
(NOT INTERCHANGEABLE WITH
CONTROL VALVE SCREWS)
Figure 4-15.Removing Bypass Piston Plug
g. Remove the pressure switches and install on replacement compressor after checking switch operation (refer to paragraph 4.10).
h. Remove clutch assemble and retain original clutch
key. Install on replacement compressor. Refer to
paragraph 4.20.2.
i. Install compressor in unit by performing the removal
steps in reverse. It is recommended that new locknuts
be used when replacing compressor. Install new gaskets on service valves and tighten bolts uniformly.
j. Leak check connections and replace filter--drier. Refer to paragraph 4.6.
k. Using refrigerant hoses designed for vacuum service,
connect a vacuum pump (see Figure 4-5) and evacu4-11
T-295
0.030 inch (0.41 to 0.76 mm). If required, remove the
eight armature spacer nuts and spacer. Add or remove
shims to adjust gap. Reinstall spacer nuts and tighten
to 7--8 ft/lbs(1.0 to 1,1 mkg).
3. Evacuate compressor to 500 microns. Backseat
compressor suction and discharge valves, start system and recheck oil level.
4. Remove manifold gauge set.
h.Reconnect wiring and test clutch operation.
1
12
4.20.3 Compressor Oil Level
2
To check, and if required correct, the compressor oil
level do the following:
11
a. Operate the coach for at least one--half hour at fast
idle speed, with the temperature controls at the coolest setting, and the compressor fully loaded. It may be
necessary to pre--heat the coach and/or operate the
system in the reheat mode to keep the compressor fully loaded throughout this procedure
10
b. Ensure the system is fully charged (refer to paragraph
4.8.1) and the compressor crankcase is warm to the
touch after fifteen minutes of operation.
7
3
4
9
5
8
6
05G - GR60
c. Shut off the system and immediately record the oil
level in the compressor sight glass. See Figure 4-17.
If the compressor is not level, an average between the
sight glass levels will have to be made to determine
level.
11
12
d. The proper oil level is between the marks on the compressor crankcase (05G compressors) or between 1/4
and 1/2 of the sight glass (05K compressors). Refer to
Figure 4-17. If the oil level is correct, release the
coach into service. If the level is above the required
amount, proceed to step e.. If the level is below the
required amount proceed to step f.
1
3
2
5
9
7
e. To remove oil and bring the level to the proper
amount, do the following:
8
05K - GR45
1. Pump down the compressor until only a slight positive pressure remains in the crankcase. Refer to paragraph 4.5.3.
1.
2.
2. Shut off the coach engine and ensure the compressor
discharge and suction service valves are frontseated.
Reclaim the remaining refrigerant in the compressor
crankcase.
3.
Electric Unloader
Valve
Suction Service
Valve Charging Port
Suction Service
Valve
Clutch
Oil Fill Plug
6.
7.
8.
9.
10.
11
Bottom Plate
Oil Drain Plug
Oil Level Sight Glass
Oil Pump
O-ring
.Discharge Service
Valve
12 .Service Port
3. Drain or pump out compressor oil until the level is
brought to the minimum for this compressor.
4.
5.
4. Evacuate the compressor to 500 microns. Backseat
the compressor service valves and repeat the oil level
check procedure.
Figure 4-17. Compressors
4.20.4 Checking Unloader Operation
To check unloader operation do the following:
a. Install a manifold gauge set as shown in Figure 4-6.
Ensure both manifold valves are frontseated and center connection is tight on blank fitting.
b. Midseat compressor suction service valve.
c. At the bus roof, disconnect the suction pressure transducer (8, Figure 1-6). This will force the controller to
f. To add oil to the compressor crankcase, do the following:
1. With the system off, connect a manifold gauge set to
the compressor suction and discharge service valves
(See Figure 4-5) and reclaim the refrigerant to below
atmospheric pressure. Shut off the reclaimer and
verify the pressure does not rise. If the pressure rises,
continue reclaiming until the pressure remains below atmospheric.
energize the unloader(s).
d. Start the bus and run in cooling lower set point if required to ensure system remains in full speed cooling.
e. Locate the unloader connector at the compressor. Observe manifold suction gauge while unplugging the
2. Add oil to compressor crankcase slowly, through the
oil fill plug opening (see Figure 4-17) to bring level
to mid range of allowed levels.
T-295
4-12
connector. Pressure should decrease 3 to 5 psi (0.2 to
0.4 bar) when the unloader is unplugged and increase
the same amount as the plug is reconnected. repeat
test for second unloader if fitted.
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.
f. If pressures do not react as described, check unloader
coil or repair unloader mechanism as required.
4.22 PRESSURE TRANSDUCER CHECKOUT
g. When testing is complete, reconnect transducer and
unloader connectors and remove manifold gauge set.
NOTE
System must be operating to check transducers.
h. Disconnection of the suction pressure transducer will
cause an “A15” alarm. Once the transducer is reconnected, the alarm will go to inactive and can then be
cleared.
a. With the system running use the driver display or
manifold gauges to check suction and/or discharge
pressure(s).
b. Use a digital volt-ohmmeter measure voltage across
the transducer at terminals A & C. See Figure 4-18.
Compare to values in Table 4-2. A reading within two
percent of the values in the table would be considered
good.
Table 4-1. Temperature Sensor Resistance
Temperature
F
C
--20
--10
0
10
20
30
32
40
50
60
70
77
80
90
100
110
120
--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
Resistance In Ohms
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
C
A
B
Figure 4-18 Transducer Terminal Location
4.23 REPLACING SENSORS AND TRANSDUCERS
a. Place main battery disconnect switch in OFF position
and lock.
b. Tag and disconnect wiring from defective sensor or
transducer.
c. Remove and replace defective sensor or transducer.
d. Connect wiring to replacement sensor or transducer.
e. Checkout replacement sensor or transducer. (Refer to
section 4.21 or 4.22, as applicable.)
f. Repair or replace any defective component(s), as required.
4.21 TEMPERATURE SENSOR CHECKOUT
a. An accurate ohmmeter must be used to check resistance values shown in Table 4-1.
4.24 LOGIC BOARD CONFIGURATION
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 accaptable. If a sensor is bad, the resistance
value would usually be much higher or lower than the
value given in Table 4-1 .
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
4-13
T-295
Table 4-3. Logic Board Configuration
Table 4-2. PressureTransducer Voltage
“/hg
Voltage
Psig
Voltage
Psig
Voltage
20”
10”
0.369
0.417
Psig
Voltage
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
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
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
1.446
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
215
220
225
230
235
240
245
250
255
260
265
270
275
280
285
290
295
300
305
310
315
320
325
2.573
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
2.406
3.455
3.504
3.553
3.602
3.651
T-295
Jumper
4-14
Description
A.
High Reheat -- Selects fan speed
B.
High Vent -- Selects fan speed
C.
Dry Heat -- Selects re--heat configuration
D.
Reheat/Cycle -- Selects clutch cycle
E.
Transducers -- Selects transducer configuration
F.
Refrigerant -- Selects refrigerant
G.
Unit Type -- Selects software configuration
H.
Unit Type -- Selects software configuration
I.
Factory -- Reserved for the manufacturer.
J.
Invert H2O -- Selects temperature switch
configuration
K.
Voltage -- Selects unit voltage
L.
Factory -- Reserved for the manufacturer.
M.
Psig/Bars -- Selects display configuration
N.
C/F -- Selects display configuration
O.
Loaded Start -- Selects start--up configuration
P.
PI Reheat -- Selects reheat algorithm
Table 4-4. R-134a Temperature - Pressure Chart
Temperature
Vacuum
Temperature
F
--40
.35
C
--40
.37
“/hg
14.6
12.3
49.4
41.6
37.08
31.25
0.49
0.42
--30
--25
--34
--32
9.7
6.7
32.8
22.7
24.64
17.00
0.33
0.23
--20
--29
3.5
11.9
8.89
0.12
--18
--16
--28
--27
2.1
0.6
7.1
2.0
5.33
1.52
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
C
--26
--24
--23
--22
--21
--20
--19
--18
--17
--16
--14
--13
--12
--11
--10
--9
--8
--7
--6
--4
--3
cm/hg kg/cm@@
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
bar
Pressure
psig
kPa
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
1.1
8.3
13.8
20.0
25.5
31.7
36.6
44.8
52.4
59.3
66.9
74.5
82.7
91.0
100.0
108.9
117.9
127.6
137.2
147.6
157.9
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
4-15
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
kPa
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
168.9
180.0
191.7
204.1
215.8
228.9
242.0
276.5
313.7
353.0
395.8
441.0
490.2
542.6
597.8
657.1
719.1
786.0
856.4
930.8
1009
1092
1180
1273
1370
1473
1580
1693
1813
1938
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
T-295
SECTION 5
ELECTRICAL
5--1 INTRODUCTION
This section includes electrical wiring schematics. The schematic shown in this section provides information for all
unit models and optional configurations. For model GR45 units, which are fitted with four evaporator and condenser
fans, the components used to control the fifth and sixth fans are not energized. For applications with OEM supplied
operating switches, the switches are wired to Logic Board connector J3 as shown. For units with a Micromate as the
operators control, there is no wiring to the Logic Board J3 connector. The Micromate is hard wired to the Logic Board
connector J2 in the same manner as shown for service port use.
5-1
T--295
LEGEND
CONNECTOR LEGEND
SYMBOLS
SYMBOL
DESCRIPTION
ATS
BPS
AMBIENT TEMPERATURE SENSOR
BOOST PUMP SIGNAL
CB1
CIRCUIT BREAKER, EF1
GROUND
CB2
CB3
CIRCUIT BREAKER, EF2
CIRCUIT BREAKER, EF3
FACTORY WIRING
CB4
CB5
CIRCUIT BREAKER, EF4
CIRCUIT BREAKER, EF5
OEM WIRING
CB6
CB7
CIRCUIT BREAKER, EF6
CIRCUIT BREAKER, CF1
CB8
CIRCUIT BREAKER, CF2
CB9
CB10
CB11
CB12
CB13
CIRCUIT BREAKER, CF3
CIRCUIT BREAKER, CF4
CIRCUIT BREAKER, CF5
CIRCUIT BREAKER, CF6
CIRCUIT BREAKER, MISC
CF1
COND MOTOR 1
CF2
CF3
COND MOTOR 2
COND MOTOR 3
CF4
COND MOTOR 4
CF5
CF6
COND MOTOR 5
COND MOTOR 6
CTH
D2
COMPRESSOR CLUTCH
EF1/2 LED ASSEMBLY
D6
D14
EF3/4 LED ASSEMBLY
EF5 LED ASSEMBLY
D17
D26
D30
EF6 LED ASSEMBLY
CF1/2 LED ASSEMBLY
CF3/4 LED ASSEMBLY
D38
D41
D51
CF5 LED ASSEMBLY
CF6 LED ASSEMBLY
CLUTCH LED ASSEMBLY
D54
D57
UV1 LED ASSEMBLY
UV2 LED ASSEMBLY
D60
FRESH AIR VALVE LED ASSEMBLY
D63
RSV LED ASSEMBLY
D66
D72
DPT
EM1
ALARM LED ASSEMBLY
SPARE LED ASSEMBLY
DISCHARGE PRESSURE TRANSDUCER
EVAP MOTOR 1
EM2
EM3
EVAP MOTOR 2
EVAP MOTOR 3
EM4
EM5
EVAP MOTOR 4
EVAP MOTOR 5
EM6
F
FAV
CONNECTOR TERMINAL
GROUND STUD
POWER STUD
CONNECTOR
NORMALLY OPEN CONTACT
A
CONNECTOR, POSITON ”A”
LAMP
DIODE
FUSE
COIL
MOTOR (EF or CF)
PRESSURE SENSOR
LED ASSEMBLY
FTS
EVAP MOTOR 6
FUSE
FRESH AIR VALVE
FREEZE TEMPERATURE SENSOR
HV
HEAT VALVE
K1
EF1/2 RELAY
K2
K3
EF3/4 REALY
EF5 RELAY
K4
K7
EF6 RELAY
CF1/2 RELAY
K8
CF3/4 RELAY
RELAY COIL
K9
K10
CF5 RELAY
CF6 RELAY
MANUAL SWITCH
K13
K14
K15
K16
CLUTCH RELAY
UV1 RALAY
UV2 RELAY
FRESH AIR RELAY
K17
K18
HEAT RELAY
FAULT RELAY
K19
K20
BOOST RELAY
SPARE RELAY
K21
K22
K23
K24
EVAP. FAN HIGH RELAY
EVAP. FAN LOW RELAY
COND. FAN HIGH RELAY
COND. FAN LOW RELAY
LPS
LOW PRESSURE SWITCH
LLS
RAS
SPT
UV1
UV2
WTS
LIQUID LINE SOLENOID
RETURN AIR SENSOR
SUCTION PRESSURE TRANSDUCER
UNLOADER SOLENOID VALVE #1
UNLOADER SOLENOID VALVE #2
WATER TEMPERATURE SWITCH
PRESSURE SWITCH
TEMPERATURE SENSOR
MANUAL RESET BREAKER
POLY SWITCH
TEMPERATURE SWITCH
MULTI--PLEX MODULE
RIBBON CABLE
SYMBOL
DESCRIPTION
J1
LOGIC POWER
J3
J4
ON/TEST
INPUT
J5
J6
RELAY BOARD INTERFACE
SENSOR
J7
JP1
DIAGNOSTIC LINK
MOTOR OVERLOAD
JP2
JP3
LOGIC BOARD INTERFACE
BOOST PUMP
JP4
JP5
CLUTCH
HEAT/FAIL
JP6
UNLOADER
W_ATS
AMBIENT TEMPERATURE SENSOR
W_COMP
W_FAV
W_HPS
W_LPS
W_LLS
COMPRESSOR
FRESH AIR VALVE
HIGH PRESSURE SWITCH
LOW PRESSURE SWITCH
LIQUID LINE
W_WTS
WATER TEMPERATURE SWITCH
Figure 5--1. Electrical Wiring Schematic Diagram - Legend
T--295
5-2
Figure 5--2. Wiring Schematic, Permanent Magnet Motors - Interconnection
5-3
T--295
VENT
HEAT
COOL
LOW
SPEED
SPEED
DPT
SPT
105F
WTS
SPA
6
23
A
21
20
C
(--)
19
B
(+)
24
C
6
5
4
3
2
1
J6
4
2
1
J4
8
7
2
4
3
5
4
3
22
W_ATS
B
A
W_ATS
B
W_LPS
GND
DATA
2
1
B
LPS
SPA
SPD
DATA
12V
A
A
24VDC
SPD
SPC
SPB
SERVICE
PORT
(--)
(+)
ATS
FTS
RAS
SPB
SPC
3
2
5
W_LPS
J2
MICROMATE
AUTO/ON
4
1
HIGH
GROUND (--)
24VDC
24VDC
24VDC
24VDC
24VDC
24VDC
DIM
SIGNAL
ALTERNATOR
SIGNAL
24VDC
J3
J2
J1
J5
3
J1
LOGIC BOARD
1
5
4
3
2
13
12
11
10
9
8
7
6
18
1
JP2
5
JP2
4
JP2
3
JP2
2
JP2
13
JP2
12
JP2
11
JP2
JP2
JP2
10
9
8
7
JP2
6
JP2
18
JP2
1
JP2
86
EVAP FAN HIGH RELAY
86
K21
K20
JP4
4
COND FAN HIGH RELAY
86
K23
COND FAN LOW RELAY
86
K24
85
85
EVAP FAN LOW RELAY
86
K22
85
85
SPARE
85
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
24V
B
W_HPS
HPS
A
W_HPS
1
JP4
24V
JP1
JP1
JP1
JP1
7
5
3
1
JP1
JUMPER
JP1
JUMPER
JP1
JUMPER
JP1
JUMPER
8
6
4
2
RELAY BOARD
86
86
86
86
86
86
86
86
86
86
86
86
K12
K9
K10
K11
K7
K8
K6
K3
K4
K5
K1
K2
85
85
85
85
85
85
85
85
85
85
85
85
D90
D48
D47
D82
D89
D46
D45
D81
D88
D24
D23
D80
D87
D22
D21
D79
K24
LOW
K23
HIGH
K22
LOW
K21
HIGH
F(150A)
POWER
CABLE
+24VDC
CB1
K1
1--120
(NOVA)
CB2
D2
CB3
K2
CB4
D6
CB5
K3
EF1
2
A
EM1
B
EF1
1
EF2
2
A
EM2
B
EF2
1
EF3
2
A
EM3
B
EF3
1
EF4
2
A
EM4
B
EF4
1
EF5
2
A
EM5
B
EF5
1
EF6
2
A
EM6
B
EF6
1
CF1
2
A
CF1
B
CF1
1
CF2
2
A
CF2
B
CF2
1
CF3
2
A
CF3
B
CF3
1
CF4
2
A
CF4
B
CF4
1
CF5
2
A
CF5
B
CF5
1
CF6
2
A
CF6
B
CF6
1
K5
K6
D14
CB6
K4
D17
CB7
K7
D26
CB8
CB9
K8
D30
CB10
CB11
K9
K11
K12
D38
CB12
K10
1--121 (NOVA)
D41
POWER CABLE (--)
MOTOR CONNECTION
MARKING
CB13
JP5
2
K16
TYPICAL ALL MOTORS
A
JP5
4
W_FAV
W_FAV
A
FAV
B
D60
B
JP5
K20
1
SPARE
D72
CIRCUIT BREAKER
CONNECTION MARKING
K14
JP6
2
W_COMP
W_COMP
C
D
UV1
JP6
4
JP6
1
W_COMP
W_COMP
F
E
UV2
JP6
3
TYPICAL ALL BREAKERS
D54
1
2
K15
ALL BREAKERS 15 AMP
D57
RELAY CONNECTION
MARKING
30
JP4
2
K13
D51
87
RELAYS K5, K6
K11 &K12
JP5
3
K17
D63
87A
87
ALL OTHERS
LLS
A
W_LLS
A
W_CTRL2
JP4
3
K18
30
W_COMP
W_COMP JP4
A
CTH
B
4
D66
K19
B
W_LLS
A
HV
B
A/C FAIL
C
W_CTRL2
JP3
3
F(15A)
JP3
3
W_CTRL2
B
+24VDC
D69
BPM +
FLOOR HEATERS
Figure 5--3. Wiring Schematic, Permanent Magnet Motors - Relays to External Components
T--295
5-4
Figure 5--4. Wiring Schematic, Electronically Communtated Motors - Interconnection
5-5
T--295
VENT
HEAT
COOL
LOW
SPEED
SPEED
DPT
SPT
105F
WTS
ATS
FTS
RAS
GND
DATA
23
A
21
20
C
(--)
19
B
(+)
24
22
C
6
5
4
3
2
1
J6
5
4
2
1
J4
8
7
2
4
3
5
4
3
2
1
B
W_ATS
B
A
W_ATS
(SEE FOLLOWING DIAGRAM)
MOTOR FAIL SIGNAL
B
W_LPS
12V
DATA
A
A
LPS
SPA
SPD
SPC
SPB
SERVICE
PORT
(--)
(+)
SPA
6
24VDC
SPD
SPC
SPB
3
2
5
W_LPS
J2
MICROMATE
AUTO/ON
4
1
HIGH
GROUND (--)
24VDC
24VDC
24VDC
24VDC
24VDC
24VDC
DIM
SIGNAL
ALTERNATOR
SIGNAL
24VDC
J3
J2
J1
J5
3
J1
LOGIC BOARD
1
5
4
3
2
13
12
11
10
9
8
7
6
18
1
JP2
5
JP2
4
JP2
3
JP2
2
JP2
13
JP2
12
JP2
11
JP2
JP2
JP2
10
9
8
7
JP2
6
JP2
18
JP2
1
JP2
86
EVAP FAN HIGH RELAY
86
K21
K20
JP4
4
COND FAN HIGH RELAY
86
K23
COND FAN LOW RELAY
86
K24
85
85
EVAP FAN LOW RELAY
86
K22
85
85
SPARE
85
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
24V
B
W_HPS
HPS
A
W_HPS
JP4
1
24V
7
5
3
JP1
JP1
JP1
JP1
1
JP1
JUMPER
8
6
4
2
JP1
JUMPER
JP1
JUMPER
JP1
JUMPER
RELAY BOARD
K4
86
85
K10
86
CF6 RELAY
CF5 RELAY
85
86
K9
CF3/4 RELAY
85
86
K8
CF1/2 RELAY
85
86
K7
85
EF6 RELAY
EF5 RELAY
85
86
K3
EF3/4 RELAY
85
86
K2
EF1/2 RELAY
85
86
K1
EF HIGH RELAY
85
86
K5
D48
D47
D46
D45
D24
D23
D22
D21
D79
K24
COND FAN LOW
K23
COND FAN HIGH
K22
EVAP FAN LOW
K21
EVAP FAN HIGH
F (125A)
POWER
+24VDC K7
CABLE
CB7
D26
K8
D30
CB8
CF1
2
A
CF1
B
CF1
1
CF2
2
A
CF2
B
CF2
1
CB9
CF3
2
A
CF3
B
CF3
1
CB10
CF4
2
A
CF4
B
CF4
1
TO J4--5
C
SEE PRECEEDING DIAGRAM
C
C
C
CB11
K9
CF5
2
A
CF5
B
CF5
1
C
D38
CB12
K10
CF6
2
A
CF6
B
CF6
1
D41
C
C
CB1
K1
D2
CB2
EF1
2
A
EF1
B
EF1
1
EF2
2
A
EF2
B
EF2
1
C
D
D
CB3
K2
D6
CB4
EF3
2
A
EF3
B
EF3
1
EF4
2
A
EF4
B
EF4
1
CB5
EF5
2
A
CF5
B
D14
EF6
2
A
EF6
B
D17
D
EF HIGH
K5
A
C
EF6
1
C
4
MOTOR CONNECTION
MARKING
TYPICAL ALL MOTORS
CF5
1
D
CB6
K4
C
C
D
K3
D
D81
CB13
JP5
2
K16
B
JP5
4
W_FAV
W_FAV
A
FAV
B
D60
JP5
1
K20
CIRCUIT BREAKER
CONNECTION MARKING
TYPICAL ALL BREAKERS
2
K14
1
JP6
2
W_COMP
W_COMP
UV1
C
D
JP6
4
JP6
1
W_COMP
W_COMP
UV2
E
F
JP6
3
D54
ALL BREAKERS 15 AMP
K15
RELAY CONNECTION
MARKING
D57
JP4
2
K13
30
SPARE
D72
87
D51
TYPICAL ALL RELAYS
JP5
3
K17
W_COMP
W_COMP JP4
CTH
4
A
B
LLS
A
W_LLS
B
W_LLS
A
HV
B
D63
JP4
3
K18
A/C FAIL
D66
K19
JP3
3
F(15A)
JP3
3
W_CTRL2
B
+24VDC
D69
BPM +
FLOOR HEATERS
Figure 5--5. Wiring Schematic, Electronically Communtated Motors - Relays To External Components
T--295
5-6
INDEX
A
F
Air Filters, 4-9
Filter--Drier, 4-6
Alarm, 2-4, 3-1
Fresh Air System, 1-4, 2-3
Alarm Clear, 3-1
Fuse, 1-6
Alarm Codes, 3-1
Alarm Queue, 3-1
H
Ambient Lockout, 1-6
Apex Unit, 1-2
Heat Valve, 4-7
Heating Cycle, 1-8
B
Heating Mode, 2-3
High Pressure Switch, 1-5, 4-5
Boost Pump, 2-3
Hour Meter, 2-4
C
L
Circuit Breaker, 1-6, 1-10, 1-11
Clutch, 2-4, 4-11
Liquid Line Solenoid, 4-8
Compressor, 1-4, 1-5, 4-10
Logic Board, 1-12, 2-1, 4-13
Condenser Coil, 4-6
Low Pressure Switch, 1-5, 1-6
Condenser Fan, 1-5, 2-4, 4-8
M
Condensing Section, 1-2
Control Panel, 1-13
Cooling Mode, 2-3
D
Maintenance Schedule, 4-1
Manifold Gauge Set, 4-2
Modes Of Operation, 2-3
DESCRIPTION, 1-1
N
Diagnostics, 2-1, 2-4, 2-5
Discharge Pressure, 2-4
Noncondensibles, 4-5
O
E
ELECTRICAL, 5-1
Oil Charge, 4-12
Evacuation, 4-4
Operating Controls, 1-4
Evaporator, 1-3
Operating Instructions, 2-1
Evaporator Coil, 4-7
OPERATION, 2-1
Evaporator Fan, 1-5, 2-4, 4-9
Index-1
T-- 295
INDEX -- Continued
P
T
Pre--Trip Inspection, 2-1
Temperature Control, 2-3
Pressure Transducer, 1-5, 4-13
Temperature Pressure Chart, 4-15
Pump Down, 4-2, 4-3
Temperature Sensor, 1-5, 4-13
Thermostatic Expansion Valve, 1-5, 4-9
R
Refrigerant Charge, 1-5, 4-2, 4-4, 4-5
Top Cover, 4-1
TROUBLESHOOTING, 3-1
Refrigerant Removal, 4-3, 4-4
Refrigeration Cycle, 1-6
U
Relay Board, 1-9
Unloaders, 2-3
S
V
SAFETY, i
Self Diagnostics, 3-1
Vent Mode, 2-3
SERVICE, 4-1
Service Valves, 4-1
W
Starting, 2-1
Stopping, 2-1
Wiring Schematics, 5-1
Suction Pressure, 2-3
Superheat, 4-10
System Parameters, 2-5
T-- 295
Index-2