It's not unheard of for heating systems to have a glitch once in a while. It could be as straightforward as a bad thermostat or an electrical problem. If your gas furnace won't shut off, here are a couple steps you can take to get a correctly working furnace again.
Examine the Air Filter
A dirty air filter causes issues for many homeowners and their HVAC system. Here's why. It restricts airflow, making your furnace work harder and run longer to satisfy your ideal 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 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 more quickly, it can drive up your heating bill and make your home feel unpleasant.
We encourage replacing flat filters once a 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 dirty and you should replace it.
If the matter was connected to a clogged air filter, putting in a new filter should fix this common problem when your heat won't turn off. If not, we suggest 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 often the problem when your furnace won't stop running.
At times having the heat turn off is as simple as adjusting an incorrect thermostat setting.
Ensure Your Thermostat is Set to “Auto”
Your thermostat has two settings, “auto” and “on,” that manage your heating system's blower motor.
“Auto” means the furnace blower will only run when the furnace does.
“On” indicates the furnace blower will run continuously. 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 seem like your furnace is not turning off, but it's really just the furnace blower you're noticing. Switching it to "auto" should solve the problem. It will also help you save money on your energy costs.
Check 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 running until it reaches your desired temp.
Remember that if it's very cold outside, your furnace will have to operate much longer than usual to keep your home warm. This is due to a big temperature difference between the cold air outside and the warm indoors.
As a check, you can try lowering the thermostat to correspond with the room. Then, wait a couple of minutes. This should make the furnace shut off in a few minutes.
Put in Fresh Batteries
If you use a programmable thermostat, it's probably battery powered. You can test replacing the 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 turn off after you switch 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 turn off? There are two spots you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch.
- Head to your breaker box and find the breaker labeled "furnace." Push the breaker switch to the right to cut power.
- Next, search for the specific power switch to your heating system. It looks like a light switch and can be found on or near your furnace. Push the switch down to cut power.
- Your furnace should be shut off now.
If you had to switch off your system at the breaker, call us at 919-578-4329 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting this problem can be as simple as replacing your air filter or adjusting thermostat settings. In other situations, you might need 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 continuously, 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 communicate via a blinking 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.
Like anything else in your home, your thermostat can wear out 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 create an energy-efficient heating and cooling schedule based on 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 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 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.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be annoying, particularly 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 count 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 919-578-4329 to schedule your appointment now.