It's not unusual for heating systems to have a glitch once in a while. It could be as simple as a bad thermostat or an electrical problem. 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 problems for numerous homeowners and their HVAC system. Here's why. It limits airflow, making your furnace work harder and run longer to satisfy your desired temperature.
This multiplies 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 down for a time to cool off. Then it will keep repeating 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 detect 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 clean filter should solve this common issue when your heat won't turn off. If not, we recommend checking your thermostat settings next.
Check the Thermostat
Your thermostat runs your furnace and simply tells 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.
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” indicates the furnace blower will operate continuously. 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 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 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, compare 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.
Keep in mind that if it's extremely cold outside, your furnace will have to operate 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 reducing the thermostat to correspond with the room. Then, wait a couple of minutes. This should make the furnace turn off momentarily.
Put in Fresh Batteries
If you have a programmable thermostat, it's likely battery powered. You can test replacing the 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 turn off after you move it to "off," you will need to cut the power.
Turn Off the Power
Thermostat seems to be working fine but your furnace still won't shut off? There are two spots 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 find the breaker labeled "furnace." Push the breaker switch to the right to cut power.
- Next, look 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. Push the switch down to shut off power.
- Your furnace should be turned off now.
If you had to turn off your system at the breaker, call us at 519-804-1617 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting this problem can be as easy as replacing your air filter or changing thermostat settings. In other situations, you might need a professional when your heater won't turn 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 sound 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 through a flashing red light on the front of your heating system.
Our Experts can identify 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.
Like other things in your home, your thermostat can break down over time and need to be replaced. If it's time 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 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 across your home. If your home or ductwork is older, your furnace might be running all the time 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 diagnosing and taking care of any air duct repair service that you require.
Depend 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 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 519-804-1617 to book your appointment now.