What to Do When Your Heater Won’t Turn Off!

It’s not uncommon for heating systems to have a problem every now and then. It could be as simple as a bad 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 restricts airflow, making your furnace work harder and run longer to meet your ideal temperature.

This multiplies usage on your furnace, as well as the odds of a malfunction and early failure.

It can also make your furnace get too hot and shut off for a time to cool down. Then it will keep repeating this process when your furnace switches on. This is called short cycling. In addition to wearing out your furnace faster, 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 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 get a new one.

If the matter was linked to a clogged air filter, replacing it with 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 Out 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 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 drive up your power bill and lead to 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 hearing. 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, check the temperature setting to the area temperature. If it’s higher 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 usual to keep your home warm. This is due to a large temperature difference between the cold air outside and the warm indoors.

As a check, you can try decreasing the setting to match the room. Then, wait a few minutes. This should make the furnace shut 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 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 move it to “off,” you will need to cut the power.

Cut the Power

Thermostat appears 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 specific power switch.

    1. Go to your breaker box and locate the breaker labeled “furnace.” Push the breaker switch to the right to cut power.
    1. Next, look for the specific 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 cut power.
    1. Your furnace should be turned off now.

If you had to switch off your system at the breaker, call us at for professional service, as you may need 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 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 out, it might sound like your furnace running nonstop, even though just the blower is running.

You might notice a furnace error code if there’s a problem with the limit switch. Your furnace will communicate via a flashing red light on the front of your heating system.

Our Experts can diagnose and correct 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.

Bad Thermostat

Like anything else 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, since they create an energy-efficient heating and cooling schedule based on your needs. Additionally, you’ll be able to set and monitor your thermostat from just about anyplace with your phone.

Leaky Air Ducts

Your furnace uses ductwork to circulate hot air to vents throughout your home. If your home or ductwork is older, your furnace might be operating constantly because 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 diagnosing and handling any air duct repair service that you require.

Depend on Our Experts for All Your Furnace Repair Needs

Troubleshooting furnace issues 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 resolve 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 to schedule your appointment now.

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