Understanding What an AC Capacitor Is and How to Replace It

It’s an inconvenience at best, if not an outright threat to your family: Your central air conditioner isn’t working. You try to diagnose the issue, and it seems like an electrical problem. Often when your AC unit isn’t getting the power it needs to keep your air temperature comfortable, a faulty capacitor is to blame.

A capacitor in an air conditioning unit works sort of like a battery. It stores up the electrical current from the electrical supply and distributes it at a consistent level so that your AC’s motors function. A typical central air conditioner has various motor components: a blower motor, a compressor motor, and a fan motor. Depending on the model, your AC unit might have one central capacitor that supplies power to all three motors, or each motor might have its own separate capacitor.

Capacitors can break down suddenly, such as when the air conditioner is hit with a sudden power surge, or they may wear down over time due to normal operational wear and tear. Signs of a capacitor near the end of its lifespan may include a humming or clicking sound coming from the AC unit. Alternatively, you may notice your air conditioner having a hard time starting, like a car with a motor that doesn’t want to turn over.

The capacitor itself is a relatively inexpensive part; a service call from an air conditioning repair service will definitely cost you more in installation costs than in parts. You might wonder, then, if you can replace an AC capacitor yourself.

Can You Replace an AC Capacitor Yourself?

Is it reasonable for the average homeowner to replace an AC capacitor? Yes, this is a minor repair you can do yourself. While many aspects of air conditioning installation, maintenance, and repair are best left to the professionals, it’s perfectly fine for the average homeowner to replace the capacitor.

The most important thing to remember about replacing an AC capacitor yourself is to disconnect the AC unit from its power source before you begin. Remember, the capacitor’s job is to store electrical current. You must make sure that it can’t shock you before you begin working on the capacitor, or else you risk serious injury. Turn off the power at the breaker panel. Next, turn your thermostat to the off position.

To replace the capacitor, do the following.

1. Remove the Access Panel

Place the panel and all of its screws in a safe place where no parts could get lost.

2. Find the Capacitor and Determine Its Type

Replace the capacitor with the correct type of replacement part. Find the capacitor, which is shaped like an aluminum can. It should have a sticker that will tell you its specifications. Now you can buy a replacement capacitor.

3. Use a Screwdriver to Discharge the Power

Discharge the stored current in the capacitor by placing the blade of a straight-head screwdriver across the two metal contacts. This step is critical to avoid a potential shock.

4. If Applicable, Label the Three Wires

Remember, some capacitors connect to more than one motor. If this is the case with your capacitor, make sure you label which wire goes to the blower, which goes to the compressor, and which goes to the fan. Typically, the capacitor will have these wires labeled F for the fan, C (for “common”) for the blower motor, and “Herm” (short for “hermetically sealed compressor”) for the compressor.

5. Detach and Remove the Capacitor

After you’ve labeled your wires, detach them from the capacitor. Then unscrew the mounting strap and take the faulty capacitor out of your AC unit.

6. Install the New Capacitor

To install the new capacitor, place the new part in the same place as the capacitor you’ve removed. Replace the mounting strap. Connect each wire to the correct spade wire connector.

That’s it, you’ve replaced your AC capacitor. Now replace the panel, turn the power back on, and reset your thermometer. If all goes well, you’ll enjoy a well-cooled home very soon.

Air Conditioning Service in Puyallup, WA

With a few simple tools you probably have around the house, you can replace a capacitor yourself. If you’re still unsure or uncomfortable working around electricity, the professionals are here to help.

Puyallup Heating & Air Conditioning offers the complete range of heating and air conditioning services for home and light commercial buildings, from calculating the heating and cooling needs of new construction to indoor air quality remediation. If you need air conditioning installation, repair, and maintenance in the Puyallup, WA area, contact us today.