IOM Manual

TRANE ®
Trouble Analysis
A. Compressor fails to starts
Problems and symptoms
Full voltage at motor terminal but motor
will not run.
Inoperative motor starter.
Open contacts of safety control of
thermal overload.
Electric circuit test shows no current
on line side of motor starter.
Electric circuit test show current on line
but not on motor side or fuse.
Voltmeter does not read proper voltage.
Motor starter holding coil is not
energized.
Probable cause
Burned-out motor.
Burned-out holding coil or broken
contacts.
Safety control of thermal overload
relays has cut outs.
a) Power failure.
b) Disconnect switch open.
Fuse down. Replace fuse
Low voltage
Open control circuit.
Compresoor will not operate.
Open contact on high pressure switch.
Discharge pressure above cut-in
setting.
Frozen compressor due to locked or
damaged mechanism
Discharge pressure above cut-in
setting of high pressure cut-out switch
B. Compressor stops
Problems and symptoms
High pressure control has cut out.
Thermal overload relay has cut out.
Winding thermostat has cut out.
Probable Cause
See H.
a) voltage too low
b)cooling load or condensing
temperature too high
Refrigerant shortage
29