Troubleshooting Guide
PROBLEM
CAUSE
REMEDY
Power failure.
Call power company.
Fuse blown or circuit breaker tripped.
Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer, or
control relay.
Replace component.
Insufficient line voltage.
Determine cause and correct.
Incorrect or faulty wiring.
Check wiring diagram and rewire correctly.
Thermostat setting too high.
Lower thermostat setting below room temperature.
Faulty wiring or loose connections in compressor
circuit.
Check wiring and repair or replace.
Compressor motor burned out, seized, or internal
over-load open.
Determine cause. Replace compressor.
Defective overload.
Determine cause and replace.
Compressor locked out
Determine cause for safety trip and reset lockout.
One leg of 3-phase power dead.
Replace fuse or reset circuit breaker. Determine cause.
Refrigerant overcharge or undercharge.
Recover refrigerant, evacuate system, and recharge to nameplate.
Defective compressor.
Replace and determine cause.
Insufficient line voltage.
Determine cause and correct.
Blocked condenser.
Determine cause and correct.
Defective overload.
Determine cause and replace.
Defective thermostat.
Replace thermostat.
Faulty condenser-fan motor.
Replace.
Restriction in refrigerant system.
Locate restriction and remove.
Dirty air filter.
Replace filter.
Unit undersized for load.
Decrease load or increase unit size.
Thermostat set too low.
Reset thermostat.
Low refrigerant charge.
Locate leak, repair, and recharge.
Air in system.
Recover refrigerant, evacuate system, and recharge.
Condenser coil dirty or restricted.
Clean coil or remove restriction.
Dirty drier filter.
Replace filter.
Dirty condenser coil.
Clean coil.
Refrigerant overcharged.
Recover excess refrigerant.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to suction line.
2. Replace TXV if stuck open or closed.
Air in system.
Recover refrigerant, evacuate system, and recharge.
Condenser air restricted or air short-cycling.
Determine cause and correct.
Low refrigerant charge.
Check for leaks, repair, and recharge.
Restriction in liquid tube.
Remove restriction.
High heat load.
Check for source and eliminate.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to suction line.
2. Replace TXV if stuck open or closed.
Refrigerant overcharged.
Recover excess refrigerant.
Dirty air filter.
Replace filter.
Low refrigerant charge.
Check for leaks, repair, and recharge.
Metering device or low side restricted.
Remove source of restriction.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to suction line.
2. Replace TXV if stuck open or closed.
Insufficient evaporator airflow.
Increase air quantity. Check filter and replace if necessary.
Temperature too low in conditioned area.
Reset thermostat.
Field-installed filter drier restricted.
Replace.
Excessive suction pressure.
Suction pressure too low.
Cooling Service Analysis
Compressor and condenser fan will not
start.
Compressor will not start but condenser
fan runs.
Compressor cycles (other than normally
satisfying thermostat).
Compressor operates continuously.
Excessive head pressure.
Head pressure too low.
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