It's not unheard of for heating systems to have a problem once in a while. It could be as straightforward as a bad thermostat or an electrical issue. If your gas furnace won't shut off, here are a few steps you can take to get a properly working furnace again.
Examine the Air Filter
A dirty air filter causes problems for many homeowners and their HVAC system. Here's why. It limits airflow, forcing your furnace to work harder and run longer to meet your desired temperature.
This increases wear and tear on your furnace, as well as the likelihood of a malfunction and early failure.
It can also make your furnace overheat and shut off for a time to cool off. Then it will keep duplicating this process when your furnace switches 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 monthly 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 see light through your filter, it's too dirty and you should get a new one.
If the matter was connected to a clogged air filter, putting in a fresh filter should solve this common issue when your heat won't turn off. If not, we suggest checking your thermostat settings next.
Check Out the Thermostat
Your thermostat controls your furnace and basically informs the unit when to turn on and off. It's usually to blame when your furnace won't stop running.
Sometimes having the heat turn off is as simple as adjusting a wrong thermostat setting.
Ensure Your Thermostat is Set to “Auto”
Your thermostat has 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 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 seem 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.
Confirm 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 reaches your desired temp.
Remember that if it's extremely cold outside, your furnace will have to run 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 reducing the setting to match the room. Then, wait a couple of minutes. This should make the furnace shut off momentarily.
Replace the Batteries
If you have a programmable thermostat, it's likely battery powered. You can test putting in new batteries to see if that resolves the issue. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't shut off after you switch it to "off," you will need to turn off the power.
Cut the Power
Thermostat seems 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 labeled "furnace." Push the breaker switch to the right to cut power.
- Next, search for the dedicated power switch to your heating system. It's similar to 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 switch off your system at the breaker, contact us at 613-707-2421 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Sometimes fixing this problem can be as simple as changing your air filter or adjusting thermostat settings. In other instances, you might need a professional when your heater won't shut off.
Fan Limit Switch Needs to Be Replaced
The furnace fan limit switch controls 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 see a furnace error code if there's an issue with the limit switch. Your furnace will communicate using a blinking red light on the front of your heating system.
Our Experts can diagnose and fix any issues 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.
Bad 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 installing a smart thermostat.
These thermostats make it simple to save energy, since they develop an energy-efficient heating and cooling schedule according to your needs. Additionally, you'll be able to set and monitor your thermostat from just about anyplace 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 operating constantly since the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow issues can be challenging to troubleshoot on your own, since it's concealed behind walls and ceilings. Our Experts can help with diagnosing and handling any air duct repair service that you require.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues can be annoying, especially when it impacts your comfort, energy efficiency and heating bill. When it comes to furnaces, there's a reason why we say we're Experts in our industry. You can depend 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 613-707-2421 to book your appointment now.