It's not uncommon 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 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 usage on your furnace, as well as the odds of a breakdown 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 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, 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 linked to a clogged air filter, replacing it with a fresh 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 runs your furnace and basically informs the unit when to turn on and off. It's usually the problem when your furnace won't stop running.
At times having the heat turn off is as easy 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” 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 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 noticing. 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, compare the temperature setting to the room temperature. If it's greater than the room air temp, your furnace will keep operating until it hits your desired temp.
Remember that if it's extremely cold outside, your furnace will have to run much longer than normal to keep your home warm. This is due to a big temperature difference between the cold air outside and the warm indoors.
As a test, you can try reducing the temperature to correspond with the room. Then, wait a couple of minutes. This should make the furnace turn off momentarily.
Put in Fresh Batteries
If you use a programmable thermostat, it's likely battery powered. You can try putting in new batteries to see if that resolves the issue. 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 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 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 shut off power.
- Next, search for the dedicated 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 shut off power.
- Your furnace should be shut off now.
If you had to switch off your system at the breaker, contact us at 937-503-7896 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 need a professional when your heater won't turn off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes out, it might seem like your furnace running continuously, even though just the blower is running.
You might notice a furnace error code if there's an issue 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 fix any issues 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.
Defective Thermostat
Like anything else in your home, your thermostat can wear out as time passes and need to be replaced. If it's time 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 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 uses ductwork to distribute 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.
Identifying 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 diagnosing 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 comes to furnaces, there's a reason why we say we're Experts in our industry. You can rely 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 937-503-7896 to schedule your appointment now.