It's not uncommon for heating systems to have a glitch every now and then. 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 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 breakdown and early failure.
It can also make your furnace overheat and shut off 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 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, pull it out and hold it up to the light. If you can't see light through your filter, it's too dirty and you should get a new one.
If the matter was connected to a clogged air filter, putting in a clean filter should solve this common issue 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 tells 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 easy as changing an incorrect thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat has two settings, “auto” and “on,” that manage your heating system's blower motor.
“Auto” indicates the furnace blower will only run when the furnace does.
“On” indicates the furnace blower will operate continuously. This constant air flow can help with heat distribution 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 turning 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 spend less 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 running until it hits your desired temp.
Keep in mind that if it's very cold outside, your furnace will have to run much longer than normal to keep your home warm. This is because of a big temperature difference between the cold air outside and the warm indoors.
As a check, you can try lowering the setting to correspond with the room. Then, wait a few minutes. This should make the furnace shut off in a few minutes.
Replace the Batteries
If you have a programmable thermostat, it's probably battery powered. You can test putting in new 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 move 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 cut 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." Move the breaker switch to the right to shut off power.
- Next, look for the dedicated power switch to your heating system. It's similar to 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, call us at 615-953-9885 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Occasionally fixing this problem can be as simple as replacing your air filter or adjusting thermostat settings. In other instances, you might want a professional when your heater won't shut off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch controls your furnace's blower motor. If the switch goes out, it might seem like your furnace running nonstop, even though just the blower is going.
You might see a furnace error code if there's an issue with the limit switch. Your furnace will speak via a flashing red light on the front of your heating system.
Our Experts can identify and fix 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.
Faulty Thermostat
Like other things in your home, your thermostat can break down as time passes and need to be replaced. If you're due for a new one, ask us about getting a smart thermostat.
These thermostats make it simple to save energy, since they develop an energy-efficient heating and cooling schedule according to your needs. Plus, you'll be able to adjust and monitor your thermostat from just about anyplace with your phone.
Leaky Air Ducts
Your furnace relies on ductwork to distribute hot air to vents throughout your home. If your home or ductwork is older, your furnace might be running constantly since the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow problems can be challenging to troubleshoot 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.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues can be inconvenient, 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 rely 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.* Call us at 615-953-9885 to book your appointment now.