It's not unheard of 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 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 wear and tear on your furnace, as well as the odds of a breakdown and premature failure.
It can also make your furnace get too hot and shut off for a time to cool down. Then it will keep repeating this process when your furnace switches 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 uncomfortable.
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, 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 fresh filter should fix this common problem 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 simply informs the unit when to turn on and off. It's usually to blame when your furnace won't stop running.
At times having the heat turn off is as simple as adjusting a wrong 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 run constantly. This constant air flow can help with heat distribution but will also increase 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 noticing. Changing it to "auto" should solve the problem. It will also help you save 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 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 warm. This is due to a large temperature difference between the cold air outside and the warm indoors.
As a test, you can try lowering the setting to correspond with the room. Then, wait a few minutes. This should make the furnace turn off momentarily.
Replace the Batteries
If you have a programmable thermostat, it's likely battery powered. You can test replacing the 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 shut off after you set 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 shut off? There are two spots you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch.
- Head to your breaker box and locate the breaker marked "furnace." Move the breaker switch to the right to shut off power.
- Next, look for the specific power switch to your heating system. It's similar to a light switch and can be found on or near your furnace. Push the switch down to shut off power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, call us at 208-488-4892 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Sometimes fixing this problem can be as easy as replacing your air filter or changing thermostat settings. In other instances, you might want 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 running.
You might see a furnace error code if there's a problem with the limit switch. Your furnace will speak using 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.
Like anything else in your home, your thermostat can wear out 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 according to your needs. Additionally, you'll be able to set and keep tabs on your thermostat from just about anyplace with your phone.
Leaky Air Ducts
Your furnace relies on ductwork to distribute hot air to vents across your home. If your home or ductwork is older, your furnace might be operating 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 hidden behind walls and ceilings. Our Experts can help with diagnosing and handling any air duct repair service that you need.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be annoying, especially 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 count 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.* Contact us at 208-488-4892 to book your appointment now.