Furnace Keeps Turning Off? Here Are a Few Possible Explanations and Solutions

If you have a furnace, you have likely experienced various problems. One of the most frustrating problems can be a furnace that keeps turning off. There are many possible reasons for this tiring malfunction. The important part to note is that there is always a solution. Do not lose hope just yet.

A furnace that turns on and off all the time is short-cycling. This can increase your utility bills and fail to keep your home warm during winter. This is a major inconvenience, but Stith Plumbing & HVAC is here to shed some light on the matter. We are a trustworthy HVAC contractor with years of experience with this particular issue. Here are 5 reasons why your furnace keeps turning off. We have also added some DIY or expert solutions along with each reason.

Problem: Dirty Filter

Despite what most homeowners think, a clogged filter is one of the leading causes of faulty furnaces and AC units. This little factor can cause a world of trouble. When your air filter is clogged, air cannot flow through properly. This can cause your heat exchanger to overheat, and this will shut your furnace off to protect it. While this may be useful for protecting your furnace, it is not useful when the temperatures have dropped below zero, leaving you shivering away in your home.

Solution: Replace Your Filter

Thankfully, there is a quick fix to this problem. You can turn your furnace off and remove the clogged filter. Then replace it with a clean filter. Before you do this, it would be wise to find out if your furnace uses disposable or reusable filters. You would not want to throw away a reusable filter if you don’t have to. Check your filter once a month and replace it if the dirt makes it hard for air to flow.

Problem: Blocked Vents

Just like your filters, your vents and ducts can get blocked too. Dirt and debris often settle and prevents air from flowing. This can also cause your heat exchanger to get too hot. Dirt is not the only thing to block your vents. Sometimes, there may be a piece of furniture blocking it.

Solution: Check Your Vents

This is a simple solution, but it is highly effective. Often all you have to do is move the piece of furniture away or clean the dirt that settled. If your vents are clear, it will stop your furnace from short-cycling. It is good to check your vents on a monthly basis. You can do it on the same day you check your air filter. At SPH, we believe in furnace maintenance!

Problem: Faulty Thermostat:

A faulty thermostat is another common problem. If your air filter is not the issue, your thermostat likely is. Thermostats start malfunctioning the older they get. However, the problem may even be an oversight or an incorrect temperature setting.

Solution: Check the Settings

This may seem silly but ensure that your thermostat is switched on and is on the “heat” setting. If it is on the correct setting, check that the temperature is programmed correctly. It is possible that your temperature setting is too low.

Your second line of defense is checking that your thermostat is communicating with your furnace. You will need two people for this part. One person should stand by the furnace to listen while the other switches the furnace on. As you increase the temperature, there should be sound inside your furnace. If you hear this sound, your thermostat is not the problem, and your furnace may have a problem. If you do not hear the sound, your thermostat is causing the issue. You will need a professional HVAC contractor to assist you with either of these outcomes.

Problem: Flame Sensor Covered in Soot

Another thing that could be causing your furnace to switch off all the time is a dirty, cracked, or soot-covered flame sensor. Your flame sensor is responsible for detecting the flame and turns the gas valve off if no flame is detected. This is a safety mechanism to ensure that harmful gas does not enter your home when the flame is not present. If your flame sensor is covered in soot, it won’t be able to detect the flame. When it can’t detect a flame, your gas valve will stay shut. Hence, your furnace won’t heat your home.

Solution: Contact A Professional

Sadly, this does not have a DIY fix. This is a serious problem that requires expert hands to repair. Not to worry. SPH is a Springdale heating specialist that takes care of your local furnace repairs. We will clean and repair your flame sensor so that your home can be warm and toasty again.

Problem: Oversized Furnace

It is possible that you installed the incorrect size furnace. That is why it is essential to have an expert heating specialist install your system. If your furnace is too big for your home, it will heat the space up too quickly and keep turning off. While this does not sound like a big problem, your home will cool down too quickly due to inconsistent cycling. You will definitely notice an increase in your utility bill if this is the case.


Unfortunately, the only way to put an end to this problem is to install a new furnace or increase the size of your home. While both of these options are highly expensive, the former will cost less. Contact us, and we will find the best solution to getting the right-sized furnace for your home.

Springdale, AR Furnace & Heating Specialists

If you have trouble with the quick DIY fixes, we can assist you. We understand that even simple solutions can be tricky if you aren’t familiar with the inner workings of a furnace. For the best local furnace repairs, trust Stith Plumbing & HVAC.

For more information on furnace maintenance, installations, and repairs, contact us to schedule your appointment. We look forward to earning your business!