It's not uncommon for heating systems to have a glitch every now and then. It could be as straightforward as a broken thermostat or an electrical issue. If your gas furnace won't shut off, here are a few steps you can take to get a correctly working furnace again.
Check the Air Filter
A dirty air filter causes issues for numerous homeowners and their HVAC system. Here's why. It limits airflow, making your furnace work harder and run longer to meet 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 off 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 faster, it can increase your heating bill and make your home feel uncomfortable.
We encourage replacing flat filters monthly 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 linked to a clogged air filter, putting in a new 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 controls your furnace and simply informs the unit when to turn on and off. It's often the problem when your furnace won't stop running.
Sometimes having the heat turn off is as simple as adjusting an incorrect thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that manage your heating system's blower motor.
“Auto” means the furnace blower will only operate when the furnace does.
“On” indicates the furnace blower will operate continuously. 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 set to "on," it will sound like your furnace is not shutting 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.
Check Your Temperature Setting
If your thermostat won't turn off heat, check 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 due to a large temperature difference between the cold air outside and the warm indoors.
As a test, you can try decreasing the thermostat to correspond with 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 putting in new batteries to see if that solves the problem. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't shut off after you move it to "off," you will need to cut the power.
Turn Off 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.
- Head 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 looks like a light switch and is located on or close to your furnace. Push the switch down to cut power.
- Your furnace should be turned off now.
If you had to switch off your system at the breaker, contact us at 918-212-8927 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 adjusting thermostat settings. In other situations, you might need a professional when your heater won't turn off.
Fan Limit Switch Needs to Be Replaced
The furnace fan limit switch controls your furnace's blower motor. If the switch goes out, it might seem like your furnace running continuously, 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 speak via a flashing 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, 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 easy to save energy, since they create an energy-efficient heating and cooling schedule based on your needs. Additionally, you'll be able to set 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 operating constantly 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 hidden behind walls and ceilings. Our Experts can help with identifying and taking care of any air duct repair service that you require.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues can be inconvenient, particularly 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 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.* Contact us at 918-212-8927 to book your appointment today.