The compressor in a central air conditioner compresses a gas refrigerant fuel to allow that fuel to move on throughout the cooling system. If the compressor fails to push out that refrigerant, the system can't function and you won't receive any cooled air. If your system has stopped cooling unexpectedly, the compressor is a good place to start troubleshooting.

Here are a few compressor-related issues that can impact your air conditioner's functionality. Call a heating and air conditioning services company, such as Arnold Service Co, for complete diagnostics and repairs.

Failed Start Capacitor

Some air conditioning units have a start capacitor, which stores electricity to help give the compressor a start-up boost when needed. If the start capacitor fails and the compressor requires that boost, the compressor will instead shut down and you won't have any cooled air.

You can test the start capacitor if you own a multi-meter that has both AC and Ohms settings. Turn off the power to your air conditioner, locate the capacitor, and remove the wires from the terminals. You need to drain the stored current even though the main power is off so hook the probes of the multi-meter to the terminals. Set the meter to AC reading and wait for the reading to drop down to zero, which indicates the charge is drained.

You can then change the multi-meter to Ohms and check to see if the reading matches the healthy Ohms range printed on the side of the capacitor body.

Failed Run Capacitor

While not every air conditioner has a start capacitor, most units have a run capacitor. The run capacitor also offers the compressor a boost but during the course of the system operating rather than start-up. If your air conditioner has started shutting down for no clear reason, you might want to test the run capacitor.

The testing process works the same for the run capacitor as the start capacitor. You only need to change up how you drain the charge by using an insulated screwdriver instead of the multi-meter. Place the screwdriver across the terminals for several moments then double check with the meter set to AC. You can then proceed to testing the Ohms.

Dead Compressor Motor

If both of the compressors test out healthy, but you're sure the compressor is the cause of your woes, the compressor motor might have failed. A motor failure isn't fixable so you will need to buy a new compressor.

Leave a compressor replacement to a qualified air conditioning services tech. Installing the compressor incorrectly can do long-term damage to your HVAC system.