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How to Tell If Your AC Contactor Is Bad or Failing

Raise your hand if you like living in Florida! Raise it again if you don’t mind when your AC breaks down. While being a Sunshine State resident has many perks, it also comes with brutally hot summers. This is why it’s essential to learn how to identify potential issues before they turn your home into a miserable sauna.

The AC contactor is one of the parts you should familiarize yourself with. It’s an AC component that needs to be replaced every now and then, but it’s a relatively easy fix.

What Is an AC Contactor?

The contactor is the part of the air conditioner that controls the flow of electricity into the unit. When you turn off your AC, the contactor goes up, blocking power. By the same token, every time you turn on the air conditioner, the contactor is lowered, allowing electricity to power the system. Once your home reaches the temperature set on the thermostat, the contactor goes up again.

3 Signs of a Bad or Failing AC Contactor

Over time, contactors experience wear and tear. This can lead to overheating. As a result, your AC won’t turn on. Since you don’t want the air conditioner to fail during the hottest months of the year, pay attention to these  signals that it’s time to replace the contactor:

  1. The condenser unit (the part of the AC that is outside your home) never shuts off. This could be a sign that the contactor has melted, leaving the air conditioner with no means to block electricity.
  2. When you turn on the AC, you hear the air conditioner humming, but it won’t fully power on.
  3. You hear a chattering sound coming from inside the air conditioning unit.

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How to Test an AC Contactor

Before removing the contactor, shut off power to the air conditioner. Do it at the thermostat AND the breaker level. Failing to do so could lead to electrocution.

Once the power is turned off, walk over to the condenser unit. The side of the unit connected to the wires is where the AC’s control panel is. Use a screwdriver to remove the side cover. You’ll see several colored wires connected to a black rectangle that’s positioned vertically. That’s the contactor. Take a picture of the wiring and contactor, so you’ll know how to reconnect the wires once you replace the defective part.

Unscrew the contactor from the side of the condenser unit (while still connected to wires). Proceed to remove the wires.

To test the contactor, you’ll need a multimeter (available at any hardware or big box store). Set it to the “OL” setting. Connect the multimeter to the low volt terminals on both sides of the contactor. If the contactor is working properly, the multimeter will show a reading between 5 and 20.

If you get a lower number or no reading at all, the contactor is not functional. Purchase a replacement and rewire, using the picture you took for reference.

Reinstall the condenser’s side paneling, and turn on the power to your air conditioner.

Professional AC Maintenance and Repair by Sansone

At Sansone, we have an entire team of skilled technicians. Whether you have issues with plumbing, air conditioning, heating, or ventilation, we can help. From repairs to installations, contact us today for all of your AC needs in South Florida.

Broward: (954) 800-2858
Palm Beach: (561) 701-8274
St. Lucie: (772) 879-5656

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