Solving a Furnace Not Shutting off With a Thermostat

Turned your thermostat off but you can’t get your furnace to shut off? Then take a look at the 6 methods in this article that will help you get your furnace to chill out.

If your furnace won’t shut off when prompted by your thermostat, try the following:

  • Turn the temperature down
  • Reset any programs
  • Turn the fan from ON to AUTO or OFF
  • Change the batteries
  • Change the air filter
  • Check the thermostat’s wiring
  • If all else fails, kill the power via the breaker or cut-off switch.

There are a number of things you can try to fix a furnace that won’t turn off. Let’s dive in to not only shut it off, but also make sure it doesn’t get stuck again.

How to Turn off Your Furnace When the Thermostat Won’t Respond

So, you adjust the settings on the thermostat to turn the furnace off. You expect to hear the sound of the fan and the blower motor slowing down to a stop but that doesn’t happen. You come back a little later and the furnace is still raging, hotter than ever.

What can you do if your thermostat won’t turn your furnace off? Aside from stressing about all the money you’re wasting heating a perfectly warm, if not now stifling house, you can do the following. Take a look at the 6 methods coming up in this article that will help you fix the problem.

Method #1 Forced Turn Off

No matter how stubborn your furnace, it can never continue to run without power.

If this was happening in my first, my first action would be to hit the cut-off switch that’s located near the furnace. If you can’t find yours, then turn off the power at the breaker.

If it’s still somehow running without any power, you may have solved the world’s energy problems! But I’d call a professional just to be sure.

After you’ve turned it off, give it 5-10 minutes and switch it back on. Start it up, and then see if you can turn it off normally. If not, then we’ve got some more diagnostics to do.

Method #2 Reset Any Programs

If turning the temperature down didn’t get the thermostat to turn off, try this next step. That is, to reset any automatic programs on the thermostat.

The thermostat may have accidentally been set on an automatic timer. An automatic timer will ensure that the thermostat does not turn off until a set amount of time has passed. This could be the reason why it is running continually.

For relief from this problem do the following.

  • Press and hold the reset button on the thermostat for 5 seconds. If you can’t find the reset button on the front panel, check under its base and on the right-hand side of the unit.
  • If the above doesn’t work (or you can’t figure out how to reset it), consult the manual. Lost it? Don’t worry – this happens all the time. Just try to find a model number on the thermostat and search the brand, model number, and “manual PDF”.
  • Alternatively, you can remove the batteries from the thermostat then wait one minute. Once the minute has passed, you can insert them again. This will reset the unit and undo any previous programming.

Method #3 Turn the Fan From ON to AUTO or OFF

Your thermostat’s fan settings could also be the cause of your furnace shut-off problem. If the fan is set to ON it will run constantly even if the furnace isn’t producing hot air. This, of course, is a massive drain on your utility bill.

To fix this problem, turn the fan from ON to AUTO or OFF using the switch on the interface. Once you have changed this setting, the fan furnace’s fan should turn itself off.

thermostat set to auto or off
Set the thermostat to AUTO or OFF

Method #4 Change the Batteries

If adjusting the temperature, programs, and fan have not fixed the problem, there is more you can do. That is, to change the thermostat’s batteries. Are the batteries in your thermostat on their way out? Then this could be the reason for your operational issues.

To change the batteries in your thermostat, do the following.

  1. Take off the thermostat’s front cover by pulling on the lever or latch. This could be on the side or underneath the thermostat.
  2. Remove the batteries and replace them
  3. Return the front cover to the thermostat
  4. Turn the thermostat on by pressing any button

Method #5 Change the Air Filter

Have you tried the methods mentioned above but are still having problems with your furnace? Then it looks like we could have a slightly more complex issue. It could be time for you to change your air filter.

So, why change the air filter? Because a dirty air filter can cause a whole host of problems. Here are just two of them.

  • A dirty air filter restricts the air from coming into your furnace. This could make it run constantly.
  • If the filter cannot take enough air in, it will not be able to breathe out hot air either. This will make the furnace take longer to heat your home and will lengthen its runtime.

But how often should you change your air filter? For some homeowners, changing the air filter once a year is enough to keep the furnace working well. For others, they find that changing the filter more frequently, even once a month is necessary.

Here are a couple of reasons why you might need to change your air filter frequently.

  • You have pets
  • You smoke indoors
  • You often have the doors and windows open
  • The air filter is small and gets clogged up quickly
  • You have the furnace on for more than 8 hours a day

But how can you know which replacement frequency is best for your home? To find out, you might wish to talk to a furnace contractor. The contractor will be able to analyze the size of the filter and how you use the furnace to come up with the best replacement plan.

These are the instructions you will need to replace your furnace’s air filter.

  1. Locate the furnace’s air filter
  2. Remove the filter and replace it with a new* one. You should ensure that the new filter is the same size as the old one. You can find the measurements of the old filter written on the side of it.
dirty air filter
Cleaning an air filter is one of the easiest ways to keep efficiency at a maximum

Method #6 Check the Thermostat’s Wiring

Another important thing to do if your thermostat is not working is to check its wiring. Faulty wiring could cause the thermostat to malfunction. If you suspect that the wiring is the issue, you will need to have it fixed by a professional.

professional changing thermostat
If the wiring is faulty, you will need to call a professional

Conclusion

Are you having trouble getting your thermostat to turn off your furnace? Then that is worrying and not to mention frustrating problem. No doubt, the 6 methods in this article have helped you to right the issue or know when to call a technician.

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Have a great day!

-Craig