It's not uncommon for heating systems to have a problem once in a while. It could be as straightforward as a bad thermostat or an electrical problem. If your gas furnace won't shut off, here are a few steps you can take to get a correctly working furnace again.
Examine the Air Filter
A dirty air filter creates problems for numerous homeowners and their HVAC system. Here's why. It limits airflow, forcing your furnace to work harder and run longer to satisfy your ideal temperature.
This increases usage on your furnace, as well as the likelihood of a breakdown and early failure.
It can also make your furnace overheat and shut down for a time to cool down. 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 uncomfortable.
We encourage 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 replace it.
If the matter was connected 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 Out the Thermostat
Your thermostat runs your furnace and basically 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 a wrong thermostat setting.
Ensure Your Thermostat is Set to “Auto”
Your thermostat has two settings, “auto” and “on,” that manage 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 circulation 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 noticing. Switching 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, compare 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 normal to keep your home warm. 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 temperature to match the room. Then, wait a few minutes. This should make the furnace turn off momentarily.
Put in New Batteries
If you use 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, switch it to "off."
If your furnace won't shut off after you switch 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 places you can cut the power to your heating unit: at the breaker box and at its dedicated power switch.
- Go to your breaker box and locate the breaker labeled "furnace." Push the breaker switch to the right to shut off power.
- Next, look for the dedicated power switch to your heating system. It looks like a light switch and is located on or close to your furnace. Move the switch down to cut power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, contact us at 315-313-6531 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 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 out, it might sound like your furnace running continuously, 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 using a flashing red light on the front of your heating system.
Our Experts can diagnose 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 anything else 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 getting a smart thermostat.
These thermostats make it easy to save energy, since they develop an energy-efficient heating and cooling schedule based on your preferences. Plus, you'll be able to adjust and keep tabs on your thermostat from just about anyplace with your phone.
Leaky Air Ducts
Your furnace relies on 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 problems can be tricky to resolve on your own, since it's hidden behind walls and ceilings. Our Experts can help with diagnosing and taking care of any air duct repair service that you require.
Rely 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 field. You can depend 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 315-313-6531 to schedule your appointment today.