It's not unusual for heating systems to have a glitch every now and then. It could be as simple as a broken thermostat or an electrical problem. If your gas furnace won't turn off, here are a few steps you can take to get a properly working furnace again.
Examine the Air Filter
A dirty air filter creates issues 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 desired temperature.
This increases 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 off for a time to cool off. 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 unpleasant.
We recommend replacing flat filters monthly and pleated filters every three months. If you can't remember the last time you got a new furnace filter, pull it out and hold it up to the light. If you can't see light through your filter, it's too dusty and you should replace it.
If the matter was linked to a clogged air filter, replacing it with a fresh 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 often to blame when your furnace won't stop running.
At times having the heat turn off is as simple as adjusting 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” 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 circulation but will also increase your power bill and lead to 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 hearing. Switching it to "auto" should resolve 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 area temperature. If it's higher than the room air temp, your furnace will keep running until it reaches your desired temp.
Keep in mind that if it's very cold outside, your furnace will have to run much longer than usual 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 reducing the setting 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 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 turn off after you switch it to "off," you will need to cut the power.
Turn Off the Power
Thermostat appears to be working fine but your furnace still won't turn off? There are two places 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." Move the breaker switch to the right to cut power.
- Next, search 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 shut off power.
- Your furnace should be shut off now.
If you had to switch off your system at the breaker, contact us at 843-619-3781 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Occasionally fixing this problem can be as easy as changing your air filter or adjusting 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 bad, 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 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 identify and fix 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 other things 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 getting a smart thermostat.
These thermostats make it simple to save energy, because they create an energy-efficient heating and cooling schedule based on your preferences. Plus, you'll be able to set and monitor your thermostat from just about anywhere with your phone.
Air Ducts Are Leaking
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 operating all the time because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow problems can be difficult 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 problems can be annoying, particularly 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 field. You can rely on our ACE-certified technicians to solve 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 843-619-3781 to schedule your appointment now.