It's not unusual for heating systems to have a glitch every now and then. 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.
Check the Air Filter
A dirty air filter creates issues for many homeowners and their HVAC system. Here's why. It limits airflow, making your furnace work harder and run longer to meet your ideal temperature.
This increases usage on your furnace, as well as the likelihood of a malfunction and early failure.
It can also make your furnace overheat and shut down 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 more quickly, it can increase your heating bill and make your home feel unpleasant.
We encourage replacing flat filters once a month 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 detect light through your filter, it's too dirty and you should get a new one.
If the matter was linked to a clogged air filter, putting in a clean filter should fix this common problem 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 simply informs 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 simple as changing an incorrect thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that control your heating system's blower motor.
“Auto” means 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 circulation 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 turning 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 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 greater than the room air temp, your furnace will keep running until it hits your desired temp.
Remember that if it's very cold outside, your furnace will have to operate much longer than normal to keep your home warm. This is due to a large temperature difference between the cold air outside and the warm indoors.
As a check, you can try decreasing the setting to correspond with the room. Then, wait a couple of minutes. This should make the furnace turn off in a few minutes.
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 problem. 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 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 shut off the power to your heating unit: at the breaker box and at its specific 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 specific power switch to your heating system. It looks like a light switch and is located on or near 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 859-905-0834 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Occasionally correcting this problem can be as simple as changing your air filter or changing thermostat settings. In other situations, you might want a professional when your heater won't turn off.
Fan Limit Switch Needs Replacing
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 going.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will communicate via 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. Sometimes this can involve replacement parts, such as the control board, faulty wiring or the fan switch itself.
Faulty Thermostat
Like other things 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 create an energy-efficient heating and cooling schedule according to your preferences. Additionally, you'll be able to adjust and keep tabs on your thermostat from just about anywhere with your phone.
Leaky Air Ducts
Your furnace uses ductwork to distribute hot air to vents throughout your home. If your home or ductwork is older, your furnace might be operating all the time because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow problems can be challenging 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.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues 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 industry. You can count on our ACE-certified technicians to resolve 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 859-905-0834 to schedule your appointment now.