It's not uncommon for heating systems to have a problem once in a while. It could be as simple as a bad thermostat or an electrical issue. If your gas furnace won't turn off, here are a few steps you can take to get a properly working furnace again.
Check the Air Filter
A dirty air filter creates issues for numerous homeowners and their HVAC system. Here's why. It limits airflow, making your furnace work harder and run longer to meet your desired temperature.
This increases usage on your furnace, as well as the odds of a breakdown and early failure.
It can also make your furnace overheat and shut off for a time to cool off. Then it will keep repeating this process when your furnace turns on. This is called short cycling. In addition to wearing out your furnace more quickly, it can increase your heating bill and make your home feel unpleasant.
We recommend replacing flat filters each month and pleated filters every three months. If you can't remember the last time you replaced your furnace filter, remove it and hold it up to the light. If you can't detect light through your filter, it's too dusty and you should get a new one.
If the matter was connected to a clogged air filter, putting in a new filter should fix this common issue when your heat won't turn off. If not, we recommend checking your thermostat settings next.
Check the Thermostat
Your thermostat controls your furnace and basically informs the unit when to turn on and off. It's usually the problem when your furnace won't stop running.
Sometimes having the heat turn off is as easy as changing an incorrect thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that control your heating system's blower motor.
“Auto” means the furnace blower will only run when the furnace does.
“On” means the furnace blower will run constantly. This constant air flow can help with heat distribution but will also increase your power bill and lead to wear and tear on your furnace.
If your thermostat is set to "on," it will sound like your furnace is not shutting off, but it's really just the furnace blower you're hearing. Switching it to "auto" should resolve the problem. It will also help you spend less money on your energy costs.
Check Your Temperature Setting
If your thermostat won't turn off heat, check the temperature setting to the room temperature. If it's higher than the room air temp, your furnace will keep operating until it hits your desired temp.
Remember that if it's extremely cold outside, your furnace will have to operate much longer than usual to keep your home cozy. This is because of a large temperature difference between the cold air outside and the warm indoors.
As a check, you can try decreasing the thermostat to correspond with the room. Then, wait a few minutes. This should make the furnace shut off momentarily.
Replace the Batteries
If you use a programmable thermostat, it's likely battery powered. You can try putting in new batteries to see if that resolves the problem. If it doesn't or if there's wiring to your electrical system, switch it to "off."
If your furnace won't turn off after you switch it to "off," you will need to turn off the power.
Cut the Power
Thermostat appears to be working fine but your furnace still won't turn off? There are two spots you can cut the power to your heating unit: at the breaker box and at its specific power switch.
- Head to your breaker box and locate the breaker marked "furnace." Push 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 can be found on or near your furnace. Move the switch down to cut power.
- Your furnace should be turned off now.
If you had to turn off your system at the breaker, contact us at 843-410-6103 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting this problem can be as easy as changing your air filter or changing thermostat settings. In other situations, you might want a professional when your heater won't shut off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes out, it might seem like your furnace running continuously, even though just the blower is going.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will communicate using a blinking red light on the front of your heating system.
Our Experts can identify and correct 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.
Like other things in your home, your thermostat can break down as time passes and need to be replaced. If it's time for a new one, ask us about installing a smart thermostat.
These thermostats make it easy to save energy, because they create 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.
Air Ducts Are Leaking
Your furnace uses ductwork to circulate hot air to vents across your home. If your home or ductwork is older, your furnace might be running constantly because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow issues can be difficult to troubleshoot on your own, since it's concealed behind walls and ceilings. Our Experts can help with identifying and taking care of any air duct repair service that you require.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be annoying, particularly when it affects your comfort, energy efficiency and heating bill. When it comes to furnaces, there's a reason why we say we're Experts in our field. You can rely on our ACE-certified technicians to resolve 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.* Call us at 843-410-6103 to book your appointment today.