It's not uncommon for heating systems to have a problem every now and then. It could be as straightforward as a broken thermostat or an electrical issue. If your gas furnace won't shut off, here are a couple steps you can take to get a properly working furnace again.
Check the Air Filter
A dirty air filter causes issues for numerous homeowners and their HVAC system. Here's why. It restricts airflow, making your furnace work harder and run longer to meet your desired temperature.
This increases usage on your furnace, as well as the likelihood of a malfunction and premature failure.
It can also make your furnace get too hot and shut off for a time to cool off. Then it will keep duplicating this process when your furnace turns on. This is known as short cycling. In addition to wearing out your furnace faster, it can drive up your heating bill and make your home feel uncomfortable.
We recommend replacing flat filters each month and pleated filters every three months. If you can't remember the last time you got a new furnace filter, pull it out and hold it up to the light. If you can't see light through your filter, it's too dusty and you should get a new one.
If the matter was linked to a clogged air filter, putting in a clean filter should fix this common problem when your heat won't turn off. If not, we suggest checking your thermostat settings next.
Check Out the Thermostat
Your thermostat runs your furnace and basically informs the unit when to turn on and off. It's often to blame when your furnace won't stop running.
At times having the heat turn off is as simple as adjusting an incorrect thermostat setting.
Ensure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that manage your heating system's blower motor.
“Auto” means the furnace blower will only operate when the furnace does.
“On” indicates the furnace blower will operate continuously. This constant air flow can help with heat circulation but will also drive up your power bill and increase wear and tear on your furnace.
If your thermostat is switched to "on," it will sound like your furnace is not shutting off, but it's really just the furnace blower you're noticing. Changing it to "auto" should solve the problem. It will also help you spend less money on your energy costs.
Confirm Your Temperature Setting
If your thermostat won't turn off heat, check the temperature setting to the room temperature. If it's greater than the room air temp, your furnace will keep running until it reaches your desired temp.
Remember that if it's extremely cold outside, your furnace will have to run much longer than normal to keep your home warm. This is because of a big temperature difference between the cold air outside and the warm indoors.
As a test, you can try lowering the temperature to correspond with the room. Then, wait a few minutes. This should make the furnace turn off momentarily.
Put in New Batteries
If you use a programmable thermostat, it's probably battery powered. You can test putting in new batteries to see if that solves the issue. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't turn off after you switch it to "off," you will need to cut the power.
Cut the Power
Thermostat appears to be working fine but your furnace still won't shut off? There are two places you can cut the power to your heating unit: at the breaker box and at its specific power switch.
- Go to your breaker box and locate the breaker labeled "furnace." Move the breaker switch to the right to cut power.
- Next, search for the specific power switch to your heating system. It looks like a light switch and is located on or close to your furnace. Move the switch down to cut power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, contact us at 901-235-1196 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Occasionally correcting this problem can be as simple as changing your air filter or changing thermostat settings. In other instances, you might need a professional when your heater won't turn off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, it might sound like your furnace running nonstop, even though just the blower is going.
You might notice a furnace error code if there's an issue with the limit switch. Your furnace will communicate through a blinking red light on the front of your heating system.
Our Experts can diagnose and fix any problems you're having with your furnace blower motor. Often this can involve replacement parts, such as the control board, faulty wiring or the fan switch itself.
Faulty Thermostat
Like anything else in your home, your thermostat can wear out as time passes and need to be replaced. If you're due for a new one, ask us about getting a smart thermostat.
These thermostats make it easy to save energy, since they develop an energy-efficient heating and cooling schedule based on your needs. Additionally, you'll be able to set and monitor your thermostat from just about anywhere with your phone.
Leaky Air Ducts
Your furnace uses ductwork to distribute hot air to vents throughout your home. If your home or ductwork is older, your furnace might be operating all the time because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow problems can be challenging to resolve on your own, since it's concealed behind walls and ceilings. Our Experts can help with identifying and handling any air duct repair service that you require.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues can be annoying, particularly when it affects your comfort, energy efficiency and heating bill. When it involves furnaces, there's a reason why we say we're Experts in our industry. You can count on our ACE-certified technicians to solve your problem quickly and affordably. And what's even better, we stand behind our HVAC system repairs with a 100% satisfaction guarantee for one year.* Contact us at 901-235-1196 to book your appointment now.