Trane CGA-SVX01A-EN Installation, Operation And Maintenance Manual page 28

C. 2nd Stage Compressor Fails To Start
Probable Cause
(1) Time delay contacts fail to close
(2) No call for cooling
(3) Unit locked out by reset relay (CR)
(4) Compressor contactor will not close
D. Compressor Short Cycles
Probable Cause
(1) Intermittent contact in control circuit
E. Compressor Runs Continuously
Probable Cause
(1) Unit undersized for load (cannot maintain water temperature)
(2) Thermostat setpoint too low
(3) Defective thermostat or control wiring
(4) Welded contacts on compressor contactor
(5) Leaky valves in compressor (indicated by abnormally low
discharge and high suction pressures)
(6) Shortage of refrigerant (indicated by reduced capacity, high
superheat, low subcooling, and low suction pressure)
F. Compressor Motor Winding Stat Open
Probable Cause
(1) Excessive load on evaporator (indicated by high supply water
temperature)
(2) Lack of motor cooling (indicated by excessive superheat)
(3) Improper voltage at compressor
(4) Internal parts of compressor damaged
© American Standard Inc. 2001
Recommended Action
Replace time delay relay
Check for the followings:
a. Defective thermostat
b. Broken or improper control winding
See (A) item (4)
See (A) item (5)
Recommended Action
Check for the followings:
a. Defective relay contacts
b. Loose wiring connections
Recommended Action
Check for cause of excessive load
Readjust thermostat
Replace thermostat
Replace or repair control wiring
Repair or replace contactor
Replace compressor
Find and repair refrigerant leak
Recharge system
Recommended Action
Check for the followings:
a. Excessive water flow
b. High return water temperature
Check for the followings:
a. Improper expansion valve setting
b. Faulty expansion valve
c. Restriction in liquid line
Check for the followings:
a. Low or imbalanced line voltage
b. Loose power wiring
c. Defective compressor contactor
Replace compressor
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CGA-SVX01A-EN