3 Reasons Why Your AC Won't Turn Off | Efficient AC, Electric & Plumbing

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AC Repair FAQ: Why Won’t My AC Turn Off?

When temperatures are high here in Austin, a properly sized AC system may run for very long periods of time in order to reach the desired indoor temperature (setpoint).

The AC system gradually reduces humidity and latent heat (heat that has built up in the walls, ceiling and surrounding surfaces) inside the home. It can take as long as an hour of runtime for every degree of temperature drop to achieve the desired setpoint inside your home. Once the desired temperature is reached, the runtime to maintain it is greatly reduced. However, if you feel your system is running far longer than normal or not achieving the desired temperature in a reasonable amount of time, it may be because of one (or more) of the following issues.

3 Common Reasons an Air Conditioner Won’t Turn off

  1. Dirty/clogged air filters – Dirty or clogged filters restrict airflow, greatly reducing the ability of the evaporator coils to cool the air. When filters impede airflow, transfer of heat (moisture) from the air is reduced, which can lead to icing or freezing of the coils. The unit may continue to run, unable to produce the desired reduction in temperature. Replace air filters regularly as directed. This alone may solve the problem and improve runtimes, but if it doesn’t, we recommend you call a qualified Austin AC repair technician to evaluate the problem and provide a solution.

    If this is a chronic issue and you have standard 1” thick filters, a larger pleated filter (4”-5”) in an upgraded filter box is worth considering. The larger filters offer more airflow, better filtration and reduced maintenance.
  2. Dirty/clogged coils – If you have been replacing your indoor air filters regularly, you may have a dirty or clogged outdoor condenser coil. Though the outdoor unit may look clean, the fins of the condenser coil can trap significant dirt and debris, including leaves and insect nests. Cottonwood is common problem in Central Texas and can impact a coil’s performance in a very short amount of time. Debris greatly reduces the ability of the coil to expel the hot air from your home. The coil may ice up or freeze, and the unit will continue to run for longer periods with little to no temperature reduction. The system becomes much less efficient and may cost more to run.

    A qualified AC repair technician has the training, products and tools to check the system and clean the coils. PLEASE BE AWARE: Coil cleaning should only be performed by a professional. You should never attempt to do it yourself. The coils can be easily damaged with the wrong procedure, resulting in expensive repairs. More importantly, though, high voltage is present, and there is significant risk for injury or death if this cleaning is not done properly.
  3. Low refrigerant (freon/puron) – Low refrigerant reduces the temperature of the evaporator coil (indoor coil) and may cause the coil to ice up. The unit will run for longer periods of time without adequately cooling the space. It is important to note that a system is only low in refrigerant when there is a leak. An experienced service technician can properly assess the system, determine if the unit has the correct refrigerant charge and address as needed.

    If your system won’t turn off or is taking longer than it previously did to reach your target temperatures (and replacing your air filters doesn’t solve it), please get in touch. A member of our highly rated AC repair team will troubleshoot this energy-wasting problem to improve your system performance and keep you cool in this Texas heat.

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