Your home's furnace works super hard to keep you and your household comfortable, but there can be times when this residential heating unit seems to have a meltdown. Some homeowners will have issues with their furnace not coming on at all, but what happens when your furnace refuses to shut off? This kind of problem can be disconcerting for sure, but there are usually logical reasons why this kind of thing occurs. Take a look at some of the likely causes why your residential furnace will not shut down like it is supposed to.
You have a faulty thermostat that is not properly reading the temperature.
One of the most likely culprits behind a furnace that will not shut down is a bad thermostat. A bad thermostat can mean something as simple as needing a battery replaced or something as serious as the whole thermostat not properly responding due to a malfunction or old age. To test the thermostat, lower the temperature on the thermostat by several degrees and see if the furnace continues to run. If the thermostat does have a battery, replace it to see if that is the problem. If the furnace continues to run and not shut down, the thermostat could be to blame. However, there could also be other problems.
You have an air filter that is completely clogged up.
The flow of air through the furnace is what helps keep heat pushing through the vents. If the air filter is blocked, the furnace will struggle to get your home up to the right temperature even though it is continuing to run. You may notice that your heat is running continuously but your house is cooler than usual. Check the filter in your unit to see if it does need to be changed, and you could have a simple fix for your problem.
Your fan relay switch is going bad.
The fan relay switch controls when the fan of the furnace kicks on and off. If this switch is going bad, the relayed signal from the thermostat to the furnace fails to register, and the fan will possibly continue to run. You may feel only intermittent heat coming from the vents even though the fan is continuing to run because the furnace burners are kicking on and off as they should. The fan relay switch is not always simple to replace on your own, so reach out to a residential furnace service for help.
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