Old Air Conditioning Won't Go Off? Troubleshoot It With These Emergency Tips

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If your old air conditioner doesn't cycle off and on properly, it can increase your cooling bill. In addition, the parts inside the unit can wear down and break from the stress. Sometimes, older air conditioners stay on when you set the thermostat on a very low temperature. The unit may also lack the power to remove the heat and cool down the home. With the right emergency tips, you can troubleshoot and try to fix the unit so that it cycles on and off correctly. Here's what you do.

Troubleshoot the Thermostat 

When air conditioners develop problems, a number of resources recommend checking the thermostat to see if it's set on the right temperature or needs new batteries. Both issues can affect how the thermostat communicates with the AC.

If the thermostat's setting is set too low, the AC may work harder and stay on longer to reach the desired temperature. Low batteries can keep the thermostat from picking up any temperature readings in the house because they're too weak. 

To see if the issues above are the causes of your AC's problems, change the batteries in the thermostat, then place the thermostat on 78 degrees, which is the recommended temperature for summer. Wait 30 minutes to see if the home feels cooler. The new temperature setting may give the AC enough time to remove the heat properly without overstressing its parts. 

If you don't see any positive changes in the home's temperature and the AC stays on, you may have a problem with the air conditioner's evaporator coil.

Examine the Evaporator Coil

The evaporator coil is the triangular piece that sits inside the indoor unit. The evaporator is responsible for cooling down hot air as it passes through it. But if less hot air passes through the coil than it's capable of cooling, it can freeze up.

One of things you can do is examine the coil to see if it contains ice. First, turn the air conditioning system off at the thermostat, then follow the steps below:

  • Remove the paneling over the air handler with an electric screwdriver.
  • Examine the tiny metal fins on the surfaces of the coil to see if ice or frost covers them. If you see these problems, place a thick towel beneath the air handler, then fill a spray bottle with hot water.
  • Coat the fins with the hot water, then wait 1 hour for the ice to melt.
  • Replace the paneling and remove the wet towel.
  • Return power to the air conditioning system, then wait 10 for the thermostat to reach the right temperature.

If the AC cycles off and on correctly, you safely solved the issue. If the unit doesn't turn off, try the next troubleshooting step.

Clean the Outdoor Unit

The last thing you can do is clear away any shrubs, plants, weeds, and other debris from around the outdoor unit. These things can keep air from traveling through the unit properly. Also, use a broom to sweep off the concrete padding beneath the unit. The unit's fan can pull in particles of dirt as it operates.

Next, disconnect power to the air conditioning system. Use a damp rag to wipe down the unit's fins. The fins look like large fish gills and usually line the sides of the outdoor unit. Pay close attention to the areas inside the fins. They can fill up with dirt.

After you complete the tips above, return power to the unit. The unit should now reach the right temperature and cycle off and on normally. 

If the emergency tips above didn't solve your problems, contact a heating and air conditioning contractor in your area for services.