Some of the most puzzling problems are centered in the compressor, the hub of the cooling function in your heating, ventilation and air conditioning system.

Here’s a great checklist of problems and potential sources of the trouble. It was put together for a catalog from ARRCO, a Cookeville, Tn. company that is in the business of remanufacturing air refrigeration equipment. The family-owned business salvages used compressors and rebuilds them –- and does the environment a great service in the process. ARRCO says it salvages about 65 pounds of steel, copper, aluminum, oil and cast iron from each compressor! Otherwise, all that material would be clogging a landfill.

At Freedom Heating and Cooling, we have dealt successfully with all of these problems. Our staff has more than 200 years experience collectively! Call (205) 444-4444 and we will be glad to help you.

The troubleshooting guide to possible problems:

1) Noisy unit

Compressor oil charge is too low or line is set too long.

Fan blade is bent, causing vibration.

Fan motor bearings are loose or worn.

Tube is rattling.

Condensing unit has loose parts.

 

2) Compressor will not start or has no hum.

Wiring is incorrect.

Fuse is blown.

Control contacts are open.

Internal thermal and voltage protector is tripped. (May take one hour to reset.)

Disconnect switch is open.

 

3) Compressor starts but start winding stays in place.

Low voltage

Wring is incorrect.

Relay contacts are stuck or welded.

Relay is defective or incorrect.

Run capacitor is defective or incorrect.

 

4) Compressor starts and runs but cycles on overload.

Voltage is low or unbalanced.

Run capacitor is defective or incorrect.

Refrigerant charge is low.

Overload protector is defective.

Head pressure is high.

Condenser is clogged or restricted.

 

5) Compressor will not start; it hums but cycles on overload protector.

Low voltage.

Wiring harness is incorrect.

Relay contacts are open, defective or incorrect.

Run capacitor is incorrect or defective.

Head-pressure is high.

 

6) Compressor tries to start when the thermostat closes but cuts out on overload before eventually starting after several attempts.

Low voltage.

Relay contact is badly pitted.

Tube, strainer, drier or discharge line may be restricted.

Thermostat differential is too close.

Air or non-condensable gases are in system.

 

7) Compressor short-cycles.

Control differential is too close.

Overload protector or high-pressure control is cutting out.

Refrigerant is undercharged or overcharged.

Leaks involve TEV, discharge valve or solenoid valve.

Thermostat differential is too close.

 

8) Head pressure is too high.

Condenser is clogged or restricted.

There’s a defect in the condenser fan.

Refrigerant is overcharged.

Discharge service valve is partly closed or the discharge line is restricted.

Air or non-condensable gases are in the system.

Water supply is shut off.

Location is too hot.