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1. Close start or disconnect switch.
2. Refer to electrical section.
3. Repair or replace control.
4. Relocate control.
5. Check wiring against diagram.
6. Replace or relocate.
7. Trace control circuit with wiring dia-
gram and repair.
8. Replace the compressor with all pre-
cautions.
1. Line disconnect switch open.
2. Overload protector tripped.
3. Control stuck in open position.
4. Control off due to cold location.
5. Wiring improper or loose.
6. Thermostat defective or improperly
installed.
7. Control circuit open.
8. Burned/open circuit motor winding.
Compressor will not start – no
hum.
TROUBLE SHOOTING CHART
SYMPTOM
CAUSES
CHECK & CORRECTIVE MEASURE
1. Additional current passing through
overload protector.
2. Low voltage to unit (or unbalanced if
three phase).
3. Overload protector defective.
4. Excessive discharge pressure.
5. Suction pressure too high.
6. Compressor too hot - return gas hot.
7.Compressor motor has a winding
shorted.
1.Check wiring diagram. Check for
added fan motors, pumps, etc. con-
nected to wrong side of protector.
2. Determine the reason and correct.
3. Check current, replace protector.
4. Check airflow across the condenser
coil, restrictions in refrigeration sys-
tem.
5. Check for possibility of misapplica-
tion. Use stronger unit.
6. Check refrigerant charge (fix leak),
add if necessary.
7. Replace compressor.
1. Check wiring against diagram.
2. Determine reason and correct.
3. Determine reason and correct, re-
place if necessary.
4. Replace compressor.
5. Replace compressor.
6. Check crankcase heater.
7. Unequilized pressure in the system.
1. Improperly wired.
2. Low voltage to unit.
3. Relay failing to close.
4.Compressor motor has a winding
open or shorted.
5. Internal mechanical trouble in com-
pressor.
6. Liquid refrigerant in compressor.
7. High discharge pressure.
Compressor starts and runs,
but short cycles on overload
protector.
Compressor will not start –
hums but trips on overload
protector.
Suction line frosted or
sweating.
Liquid line frosted or
sweating.
1. Expansion valve passing excess re-
frigerant or is oversized.
2. Expansion valve stuck open.
3. Evaporator fan not running.
4. Overcharge of refrigerant.
1. Restriction in dehydrator or strainer.
2. Liquid shut-off valve partially closed.
1.Re-adjust valve or replace with
smaller valve.
2. Clean valve of foreign particles, re-
place if necessary.
3. Determine reason and correct.
4. Correct charge.
1. Replace part.
2. Open valve fully.