What to Do When Your Heater Wont Turn Off!

It's not uncommon for heating systems to have a glitch every now and then. It could be as simple 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 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 desired temperature.

This increases wear and tear on your furnace, as well as the odds of a malfunction and early failure.

It can also make your furnace overheat and shut down for a time to cool off. Then it will keep duplicating this process when your furnace switches 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 uncomfortable.

We recommend 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, 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 connected to a clogged air filter, replacing it with a new filter should fix this common issue when your heat won't turn off. If not, we suggest 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 often to blame when your furnace won't stop running.

Sometimes having the heat turn off is as easy as changing 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” indicates the furnace blower will only operate when the furnace does.

“On” means 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 seem like your furnace is not turning 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.

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 operating until it hits 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 cozy. 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 thermostat to match the room. Then, wait a couple of 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 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 turn off 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 shut off the power to your heating unit: at the breaker box and at its specific power switch.

  1. Head to your breaker box and locate the breaker marked "furnace." Move the breaker switch to the right to shut off power.
  2. Next, look for the specific 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.
  3. Your furnace should be turned off now.

If you had to switch off your system at the breaker, call us at 678-235-9699 for professional service, as you may require furnace repair.

What Causes a Furnace to Keep Running?

Sometimes 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 turn off.

Fan Limit Switch Needs to Be Replaced

The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, it might seem like your furnace running nonstop, 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 identify and correct any problems 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.

Bad Thermostat

Like other things in your home, your thermostat can break down over time 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 develop an energy-efficient heating and cooling schedule based on your preferences. Additionally, you'll be able to adjust and keep tabs on your thermostat from just about anywhere with your phone.

Air Ducts Are Leaking

Your furnace uses ductwork to circulate 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.

Diagnosing this leaky ductwork and other airflow issues can be challenging to resolve 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 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 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 678-235-9699 to schedule your appointment now.

Contact Us