Checking out a air conditioner compressor and compressor problems FIRST...
Checking out a air conditioner compressor and compressor problems
FIRST DISCONNECT ALL ELECTRICAL POWER
Ohm the windings
C to R = example 1.2
C to S = example 3.2
R to S = example 4.4 total of C to R and C to S or very close.
Then ohm each terminal to ground you shouldn't get any reading
If the compressor is hot or you tried to start it, the ohms will be close but not exact.
No reading from C to R or C to S open winding or thermal overload.
Let compressor completely cool down then ohm the C to R and C to S again
If it’s an open overload, you will get an ohm reading after it cools down and the overload closes,
you may just need to add refrigerant.
No reading from R to S and C to S open start winding.
In case of any open windings the compressor will have to be replaced.
If the compressor is getting the proper voltage and won’t start, it could be locked up.
You need an Ammeter to check this to see if it’s drawing locked rotor amps (60 amps or above)
You also need to check the run and start capacitor.
A bad run or start capacitor, the compressor won’t run, it will just hum.
If the compressor will run, but quits after a while and all of the above checks out OK.
It could be drawing high amps ( you will need an ammeter to check this out). Dirty condenser or condenser motor not running, overcharge of refrigerant, shunted windings, bad bearings in compressor.
The compressor gets hot and Suction or big line coming in to outdoor unit is warm or slightly cool, you are low on charge or metering device bad or stopped up.
If compressor runs for a while and quits and the suction line is frozen, cold or cool, then the filter, evaporator or condenser coils are dirty or plugged up, blower or fan motor not running and unit going off on high or low pressure switches.
on Dec 29, 2009 | Heating & Cooling