It's not unusual for heating systems to have a glitch every now and then. It could be as simple 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 creates issues for many homeowners and their HVAC system. Here's why. It limits airflow, making your furnace 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 down. Then it will keep duplicating this process when your furnace switches on. This is called 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 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 detect light through your filter, it's too dusty and you should replace it.
If the matter was connected to a clogged air filter, putting in a new filter should solve 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 basically informs 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 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” 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 switched to "on," it will sound like your furnace is not shutting off, but it's really just the furnace blower you're hearing. 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, check 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.
Keep in mind that if it's extremely cold outside, your furnace will have to run much longer than usual to keep your home warm. This is because of a large temperature difference between the cold air outside and the warm indoors.
As a test, you can try lowering the temperature to match the room. Then, wait a few minutes. This should make the furnace shut off momentarily.
Put in New Batteries
If you use a programmable thermostat, it's probably battery powered. You can try replacing the batteries to see if that solves 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 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 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." Push the breaker switch to the right to cut power.
- Next, look for the specific power switch to your heating system. It's similar to a light switch and is located on or near your furnace. Push the switch down to shut off power.
- Your furnace should be turned off now.
If you had to turn off your system at the breaker, contact us at 301-476-4577 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting 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 shut off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes out, it might sound 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 through a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any issues you're having with your furnace blower motor. Often this can involve replacement parts, like the control board, faulty wiring or the fan switch itself.
Like other things in your home, your thermostat can break down as time passes and need to be replaced. If it's time 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 according to your preferences. Additionally, you'll be able to set and keep tabs on your thermostat from just about anyplace with your phone.
Leaky Air Ducts
Your furnace uses ductwork to circulate hot air to vents across your home. If your home or ductwork is older, your furnace might be running all the time since the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow issues can be tricky to troubleshoot on your own, since it's hidden behind walls and ceilings. Our Experts can help with identifying and handling 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 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 stand behind our HVAC system repairs with a 100% satisfaction guarantee for one year.* Call us at 301-476-4577 to book your appointment now.