It's not unheard of for heating systems to have a glitch 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 few steps you can take to get a properly working furnace again.
Check the Air Filter
A dirty air filter causes problems for many 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 wear and tear 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 repeating this process when your furnace switches on. This is known as short cycling. In addition to wearing out your furnace more quickly, it can increase 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, remove it and hold it up to the light. If you can't see light through your filter, it's too dirty and you should replace it.
If the matter was connected to a clogged air filter, putting in a fresh filter should solve this common problem 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 informs 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 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” 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 drive up your power bill and increase 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 hearing. Changing it to "auto" should resolve 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 higher than the room air temp, your furnace will keep running until it hits your desired temp.
Keep in mind that if it's very cold outside, your furnace will have to operate 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 test, you can try reducing the thermostat to match the room. Then, wait a couple of minutes. This should make the furnace shut off in a few minutes.
Replace the Batteries
If you use a programmable thermostat, it's probably battery powered. You can test putting in new batteries to see if that solves 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 move it to "off," you will need to cut the power.
Cut the Power
Thermostat appears to be working fine but your furnace still won't shut off? There are two places you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch.
- Go to your breaker box and find the breaker labeled "furnace." Push the breaker switch to the right to shut off power.
- Next, search for the dedicated 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 601-852-3105 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 shut off.
Fan Limit Switch Needs to Be Replaced
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes bad, it might seem like your furnace running nonstop, 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 communicate using a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any issues you're having with your furnace blower motor. Often this can involve replacement parts, like the control board, faulty wiring or the fan switch itself.
Defective Thermostat
Like anything else in your home, your thermostat can break down 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, since they create an energy-efficient heating and cooling schedule according to your preferences. Plus, you'll be able to adjust and keep tabs on your thermostat from just about anywhere 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.
Identifying this leaky ductwork and other airflow problems 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 need.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be annoying, especially when it impacts 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 solve 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 601-852-3105 to book your appointment now.