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Furnace Blower Won'T Turn Off? Check Your Thermostat

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An issue that can plague many homeowners is a constantly running furnace blower. There are many reasons this can happen, but one of the most common – and easiest to fix – is because of your thermostat.

The Thermostat to Furnace Blower Connection

Your furnace's blower is the key to heated air circulation around your house. However, your blower's operation is set to a circuit and should only turn on when your furnace is actually running. Sometimes, something happens and your blower becomes stuck and stays on rather than stopping. By checking on your thermostat, you can remedy this problem the majority of the time.

The Heat's Turned Up

Look at your thermostat. Is the heat turned up? This may seem like a no-brainer, but it's something that you can overlook.

  • Maybe you turned it up earlier and forgot to turn it back down again
  • Maybe you or someone in the house brushed against it and accidentally turned it up
  • Maybe you have it on an automatic timer and forgot

In any of these cases, simply try turning the thermostat down.

The Thermostat's Area is Too Cool

The thermostat reacts to its surrounding temperature. That's why thermostat placement is very important. If the area housing the thermostat is cooler than the rest of the house, then your thermostat will constantly try to warm up the house.

So while the rest of your home feels like a sauna, your thermostat is thinking it's far cooler than that. The furnace blower will stay on thinking it's trying its hardest to warm up everything.

The Fan Switch is "On"

Another thing to check is the fan setting. The majority of thermostats will have an "on" and "auto" toggle. Mostly, you should keep the fan set to auto. You should change it to "on" if you want the blower to keep going even when the furnace isn't actively creating hot air.

One of the main reasons to switch to "on" is to help with uneven heating distribution in your home. Otherwise, leave it on "auto." Some more modern thermostats may have more options for blower operation such as timed intervals.

Other Issues Caused by a Thermostat

While the furnace blower is one thing that a thermostat can affect, many other problems can crop up as well. Your furnace and thermostat have an extremely close relationship. You can solve many furnace problems just by checking it. Sometimes it's an issue that requires a professional such a faulty wiring between the furnace and thermostat.

Of course, there are a plethora of issues that can occur that have nothing to do with your thermostat. When in doubt, always contact a professional furnace repair service to have a look at your malfunctioning furnace.