It's not unusual for heating systems to have a problem every now and then. It could be as straightforward as a bad thermostat or an electrical problem. If your gas furnace won't turn off, here are a couple steps you can take to get a correctly working furnace again.
Check the Air Filter
A dirty air filter causes problems for many 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 multiplies wear and tear on your furnace, as well as the likelihood of a breakdown 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 called short cycling. In addition to wearing out your furnace faster, it can drive up 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 got a new 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 replace it.
If the matter was linked to a clogged air filter, replacing it with a fresh filter should fix this common issue when your heat won't turn off. If not, we recommend checking your thermostat settings next.
Check Out the Thermostat
Your thermostat runs your furnace and simply 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 easy 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” indicates the furnace blower will only operate when the furnace does.
“On” means 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 set to "on," it will seem like your furnace is not shutting off, but it's really just the furnace blower you're noticing. Changing 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 area 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 run much longer than normal to keep your home cozy. This is due to a big temperature difference between the cold air outside and the warm indoors.
As a test, you can try reducing the thermostat to correspond with the room. Then, wait a few minutes. This should make the furnace turn off in a few minutes.
Put in Fresh Batteries
If you use a programmable thermostat, it's probably 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, switch it to "off."
If your furnace won't shut off after you set 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 shut off? There are two places you can shut off the power to your heating unit: at the breaker box and at its specific power switch.
- Go to your breaker box and find the breaker marked "furnace." Move the breaker switch to the right to shut off power.
- Next, search for the dedicated power switch to your heating system. It looks like a light switch and can be found on or close to your furnace. Move the switch down to cut power.
- Your furnace should be shut off now.
If you had to switch off your system at the breaker, contact us at 403-279-5760 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Occasionally 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 to Be Replaced
The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, it might seem like your furnace running nonstop, even though just the blower is running.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will speak through a blinking red light on the front of your heating system.
Our Experts can diagnose and correct any issues you're having with your furnace blower motor. Sometimes this can involve replacement parts, such as the control board, faulty wiring or the fan switch itself.
Defective Thermostat
Like other things in your home, your thermostat can break down over time 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, because they create an energy-efficient heating and cooling schedule based on your needs. Plus, you'll be able to adjust and keep tabs on your thermostat from just about anyplace with your phone.
Air Ducts Are Leaking
Your furnace uses ductwork to distribute 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.
Identifying this leaky ductwork and other airflow issues can be tricky to resolve 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.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be inconvenient, especially 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 field. You can depend on our ACE-certified technicians to solve your problem quickly and affordably. And what's even better, we back our HVAC system repairs with a 100% satisfaction guarantee for one year.* Call us at 403-279-5760 to book your appointment today.