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3 Small Parts That Keep Your AC From Working When They Go Bad

by Feride Halma

Some parts of your air conditioner have a shorter lifespan than others. Sturdy parts such as the compressor may last the entire life of your AC, but parts like the capacitor may wear out much earlier and need to be replaced. Even if you keep up with maintenance, you may still need AC repairs occasionally to replace old parts. Here's a look at three small parts that can fail and cause your AC to malfunction.

1. The Contactor

The contactor is a small part in the condenser that allows power to move into the condenser and to the fan motor and compressor. When the thermostat senses it's time to trigger the AC, it sends a signal to the control board in the air handler that sends a small amount of voltage to the contactor in the condenser.

When the contactor is energized, it allows power from the disconnect box to flow into the condenser to power up the fan motor and compressor so your AC kicks on. When the contactor is bad, your AC won't start up. An AC repair technician can test the contactor with a meter to see if it's broken, and if it is, they can solve the problem by replacing the bad part with a new contactor.

2. The Capacitor

Your AC has a couple of capacitors. One is in the condenser and helps power the compressor and fan motor. The other is in the air handler and helps power the blower motor. A capacitor can be a start or dual-run capacitor. A start capacitor provides an initial boost of power that helps the motor start-up. A dual-run capacitor supplies start-up power as well as continuous power while the motor is running.

When the capacitor in your AC dies, the part it supplies power to will stop working. That means the fan motor, compressor, or blower could stop functioning in your AC unit. You might only hear humming instead of the regular fan noises.

A bad capacitor needs to be replaced promptly. If the compressor or blower fan motor doesn't work, your home won't cool down. If the condenser fan motor stops working, the condenser will overheat, and that could cause damage to the parts or keep your AC from working well enough to cool your house.

3. The Fuses

AC fuses are inexpensive parts that can go bad due to age or a power surge. The fuses are in the disconnect box that's usually mounted on your house near the condenser. A power cable leads from your electrical panel to the disconnect box and another cable goes from the disconnect box to the condenser.

When an AC repair technician works on your condenser, they pull the fuses out of the disconnect box to kill the power to the AC without having to flip off the breaker in your electrical panel.

The fuses have to be in good shape and secured in the disconnect box for power to flow to your AC. When the fuses blow, your AC won't start up. Fortunately, replacing the fuses is one of the easiest AC repairs to do. All the technician has to do is open the disconnect box, pull out the old fuses, and put the new ones in. For more information on AC repair, contact a professional near you.