An air conditioning compressor is the heart of the the unit and can be a real problem if not working.
There are many things that can cause a compressor to stop working.
Below is a list of some common issues to look for when troubleshooting a unit.
Five Reasons an Air Conditioner Compressor Will Not Start
A bad capacitor will not start a compressor and will need to be replaced if bad.
Testing the capacitor is easy enough with a HVAC multi meter. They are also low cost parts to replace.
2… Condensing Fan Motor Failure
A bad condensing fan motor will stop a compressor from working. This can be tied to a bad capacitor since Start Run capacitors are often in the same package.
When the Fan motor goes bad the compressor will kick on for a short while then stop when the Head Pressure builds up.
Since the heat is not dissipated away from the unit the Amps and heat will build up making the compressor overload and trip off.
If a unit is left On the compressor will cool down and kick back On, going into a bad cycle of running for a short while, over heating and kicking off. Often an Air Conditioner becomes loud when this happens.
This could potentiality damage the compressor since the pressures can get high and pull a lot of Amps.
The Contacts control the main high 220 volts coming into a unit.
It uses a low voltage contactors relay to control the high voltage which can go bad and not allow any voltage though.
Common problem include pitting or the relay coil winding itself going bad.
4… Electrical Short
If the winding on the Compressor goes bad it will cause the unit to ground out.
The breaker will throw when this happens. It can happen for many reasons such as a small bug got into the unit and the compressor wiring or simply age.
5… Float Controls
All A/C units need to drain water when it is humid. If the drain pans or hoses become backed up float controls can turn a unit off.
The above are a few of the main problem a unit can have.
It can of course simply have a mechanical failure and stop working. If you have run into problems let us know in the comments below.