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Table 34 — Cooling Service Analysis
PROBLEM CAUSE REMEDY
Compressor and condenser fan
will not start.
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.
Compressor will not start
but condenser fan runs.
Faulty wiring or loose connections in com-
pressor circuit.
Check wiring and repair or replace.
Compressor motor burned out, seized, or
internal overload open.
Determine cause. Replace compressor.
Defective run/start capacitor, overload, or
start relay.
Determine cause and replace.
One leg of three-phase power dead. Replace fuse or reset circuit breaker. Determine
cause.
Compressor cycles (other than
normally satisfying thermostat).
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 run/start capacitor, overload, or
start relay.
Determine cause and replace.
Defective thermostat. Replace thermostat.
Faulty condenser-fan motor or capacitor. Replace.
Restriction in refrigerant system. Locate restriction and remove.
Compressor operates continuously.
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.
Leaking valves in compressor. Replace compressor.
Air in system. Recover refrigerant, evacuate system, and
recharge.
Condenser coil dirty or restricted. Clean coil or remove restriction.
Excessive head pressure.
Dirty air filter. Replace filter.
Dirty condenser coil. Clean coil.
Refrigerant overcharged. Remove excess refrigerant.
Air in system. Recover refrigerant, evacuate system, and
recharge.
Condenser air restricted or air short-cycling. Determine cause and correct.
Head pressure too low.
Low refrigerant charge. Check for leaks; repair, and recharge.
Compressor valves leaking. Replace compressor.
Restriction in liquid tube. Remove restriction.
Excessive suction pressure.
High heat load. Check for source and eliminate.
Compressor valves leaking. Replace compressor.
Refrigerant overcharged. Recover excess refrigerant.
Suction pressure too low.
Dirty air filter. Replace filter.
Low refrigerant charge. Check for leaks; repair, and recharge.
Metering device or low side restricted. Remove source of restriction.
Insufficient evaporator airflow. Increase air quantity. Check filter and replace if
necessary.
Temperature too low in conditioned area. Reset thermostat.
Outdoor ambient below 25 F. Install low-ambient kit.
Evaporator fan will not shut off.
Time off delay not finished. Wait for 30-second off delay.
Compressor makes excessive
noise (48TJ007 scroll only).
Compressor rotating in wrong direction. Reverse the 3-phase power leads as described in
the Start-Up section on page 37.