Why Does My Furnace Keep Turning Off?

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There are a number of different safety features on a furnace, and one or more of these are likely the cause of the incessant powering on and off of your unit. Since these features are in place to prevent a catastrophic malfunction of the system, it is probably a sign that your furnace needs some attention before it can function normally.

Furnace Fails When Cycling Up
If your furnace won’t even ignite, there are switches that should be checked by a professional like the ones at Above and Beyond Heating and Cooling who service the Edmond and Oklahoma City metro area. The induced draft motor, (IDM,) blows the air out of your furnace to ensure that any gas build-up does not ignite. A pressure switch will prevent the furnace from igniting the unspent fuel if the IDM is not running. To prevent the unit from filling with fuel that isn’t being burned off, your furnace also has an internal flame recognition system to detect the presence of fire and shut down if it doesn’t.

Furnace Ignites and Immediately Shuts Down
When your furnace starts to run but then abruptly shuts itself off again, this could be a sign that something else is to blame. One item to check is the flue-limit switch, which monitors if the air is being properly ventilated out of the flue and will shut down the system if it detects an issue with diminished ventilation. However, the most common culprit for a furnace behaving this way is the high-limit switch, which turns a furnace off when the internal temperature gets too high. The two components that need to be inspected to determine if they’re a problem for the high-limit switch are:

  • Air filters, which can get clogged
  • Thermostats, which can fail without warning

At Above and Beyond Heating and Cooling, we work with all popular models to find the issue with your system and have everything running again before the problem gets worse. We can advise you on the best course of action and show you options if a replacement is needed. We have expert technicians who can handle any problem with air conditioning, filter replacement, duct repair, routine maintenance, and more. Contact us today in Oklahoma City or Edmond to find out more about how we can help you.

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