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 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 creates problems for many homeowners and their HVAC system. Here's why. It limits airflow, forcing your furnace to work harder and run longer to meet your ideal temperature.
This multiplies wear and tear on your furnace, as well as the odds 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 repeating 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 uncomfortable.
We recommend replacing flat filters once a month 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 see light through your filter, it's too dusty and you should get a new one.
If the matter was connected 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 the Thermostat
Your thermostat runs your furnace and simply tells 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 changing a wrong 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 run when the furnace does.
“On” means the furnace blower will run continuously. 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 hearing. Switching it to "auto" should solve 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, check the temperature setting to the area temperature. If it's greater than the room air temp, your furnace will keep operating until it reaches your desired temp.
Remember that if it's very cold outside, your furnace will have to run much longer than normal to keep your home cozy. This is because of a big temperature difference between the cold air outside and the warm indoors.
As a check, you can try decreasing the thermostat to match the room. Then, wait a couple of minutes. This should make the furnace turn off in a few minutes.
Put in New Batteries
If you use a programmable thermostat, it's likely battery powered. You can try replacing the batteries to see if that resolves the problem. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't turn off after you switch it to "off," you will need to cut the power.
Cut the Power
Thermostat seems 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 specific power switch.
- Go to your breaker box and locate the breaker marked "furnace." Push the breaker switch to the right to cut power.
- Next, look for the dedicated power switch to your heating system. It's similar to a light switch and is located on or near your furnace. Push the switch down to cut power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, call us at 251-202-7503 for professional service, as you may need 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 instances, 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 speak through a blinking red light on the front of your heating system.
Our Experts can identify and correct any problems you're having with your furnace blower motor. Sometimes this can involve replacement parts, like 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 easy to save energy, because they develop an energy-efficient heating and cooling schedule based on your needs. Additionally, 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 operating all the time since the ductwork is leaking hot air in the attic.
Diagnosing 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 identifying and taking care of 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 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 251-202-7503 to book your appointment today.