AC Capacitor - What It Does, Why It Fails and How to Fix It?

The Air Conditioning Capacitor is one of the most vital components in your air conditioner. It stores energy and pushes it onto the DC power supply so that your air conditioner can provide a consistent voltage.

A capacitor is typically found in the start and run circuits of an air conditioner, as well as heat pumps. The start capacitor stores energy for the air conditioner to begin running, while the run capacitor provides the additional energy required to run the compressor and fan motors.

When the capacitor is bad, your air conditioner will have a hard time starting up and won’t cool properly. You may also notice your electric bills rising as your system strains to keep up with the demand for cool air.

Common Problems with a Capacitor:
Overheating, such as when the unit sits in full sun for extended periods, can shorten the life of your AC capacitor. In addition, power surges from fluctuating electricity in the electrical grid or an overloaded circuit can also damage your AC capacitor.

How to Test Your Capacitor:
To determine whether your AC capacitor needs replacement, a heating and cooling professional will use a multimeter. This tool can test the capacitance of a capacitor by charging it with a known current and measuring the resulting voltage.