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10-1008-194 Rev. 2
TROUBLE SHOOTING
Basic Air Conditioning Trouble Shooting Check List
1.
Check manufacturer’s nameplate located on the unit for
correct power supply.
2.
Turn the power to the unit on. The evaporator (Enclosure or “COLD” air) fan should come on. Is
there airflow?
YES, proceed to step # 3.
NO,
possible:
Open
motor
winding
Stuck fan motor
Obstructed
blades
3.
Check thermostat setting? Adjust thermostat to the lowest setting. This should turn the
condenser fan and the compressor on. Did condenser fan and compressor come on when the thermostat
was turned on?
YES, proceed to step #4.
NO,
possible:
Defective
thermostat
4.
Are both fans and the compressor running? If not the unit will not cool properly.
5.
Check condenser ( Ambient or “HOT” air ) fan for airflow. Is there airflow ?
YES, proceed to step # 6.
NO,
possible:
Defective
thermostat
Open
motor
winding
Stuck fan motor
Obstructed
blades
6.
Carefully check the compressor for operation - motor should cause slight vibration, and the outer
case of the compressor should be warm.
YES, wait 5 minutes, then proceed to step #7.
NO, possible:
Defective thermostat
Defective
capacitor
Defective
overload
Defective relay
7
Make sure the coils are clean. Then check evaporator “air in” and “air out” temperatures. If the
temperatures are the same:
Possible loss of refrigerant
Possible bad valves in the compressor
8.
To check for a bad thermostat. Turn power to the unit off. Remove control box cover, place both
thermostat wires onto one terminal (replace control box cover for safety). This will bypass the
switch in the thermostat. Turn the power on. If both fans and the compressor come on, the
thermostat needs to be replaced.
Repair or Replace
defective parts.
Replace part.
Repair or Replace
defective parts.
Repair or Replace
defective parts.
Repair or Replace
defective parts.
