How to Tell If Your AC Capacitor Is Bad

How to Tell If Your AC Capacitor Is Bad

Looking to learn how to perform an air conditioner capacitor test? More importantly, are you looking to learn why you should perform such a test? Air conditioning systems are intricate appliances made up of lots of parts working harmoniously to keep your home comfortable year-round. As with any appliance, there will most likely come a time when your AC malfunctions. When this happens, it can be extremely frustrating, especially if you aren’t sure what part or component is causing the issue. One of the lesser-known culprits of air conditioning system issues is a faulty capacitor. Here’s how you can tell if your capacitor needs replacing and what you can do about it:

What is an AC Capacitor?

First thing’s first, an air conditioning capacitor is used in HVAC systems to run the compressor. Capacitors are electrical devices that store an electrical charge to be used later on in conjunction with other parts of an AC system. Capacitors have two electrical ratings that measure the amount of charge that the unit can effectively store.

There are generally two different types of capacitors that are used in different situations.

Run capacitors: These are the standard for HVAC units as well as air conditioners and heat pumps. They are used in conjunction with fan motors and compressors.

Start capacitors: In some air conditioners, start capacitors are used. These simply work in conjunction with the compressor to provide extra torque.

Air Conditioner Capacitor Test

Digital meters: Testing your AC’s capacitor yourself is doable with the help of a digital meter with a capacitance setting. To test the capacitor, shut off the power supply to the unit and short the two terminals that are located on the capacitor so that they’re discharged and won’t run the risk of shocking you. After you disconnect the wires from the capacitor, place the leads of the meter on the terminals to get an accurate reading. In most cases, the reading should fall within 6% of the capacitor’s rating, but if the reading falls below it’s time to replace the capacitor.

Analog meters: Testing a capacitor with an analog meter varies slightly than with a digital meter. First, the meter should be set to the resistance setting. Shut off the power and discharge the capacitor while also disconnecting the wires. Put the meter on the highest resistance setting and place the lead on the terminals and assess the reading. A properly functioning capacitor should start at zero and go up to the highest reading possible.

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