What to Do When Your Heater Wont Turn Off!

It's not unheard of for heating systems to have a glitch every now and then. It could be as simple as a broken thermostat or an electrical issue. If your gas furnace won't shut off, here are a couple steps you can take to get a properly working furnace again.

Check the Air Filter

A dirty air filter causes issues for many homeowners and their HVAC system. Here's why. It restricts airflow, forcing your furnace to work harder and run longer to satisfy your ideal temperature.

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

It can also make your furnace get too hot 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 uncomfortable.

We recommend 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 detect light through your filter, it's too dirty and you should replace it.

If the matter was linked to a clogged air filter, putting in a fresh filter should fix this common problem when your heat won't turn off. If not, we recommend checking your thermostat settings next.

Check Out the Thermostat

Your thermostat controls your furnace and basically tells 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 simple as changing an incorrect thermostat setting.

Make Sure Your Thermostat is Set to “Auto”

Your thermostat has two settings, “auto” and “on,” that control your heating system's blower motor.

“Auto” means the furnace blower will only run when the furnace does.

“On” means the furnace blower will operate 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 switched to "on," it will seem like your furnace is not shutting off, but it's really just the furnace blower you're noticing. Changing it to "auto" should solve the problem. It will also help you save money on your energy costs.

Confirm 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.

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 big temperature difference between the cold air outside and the warm indoors.

As a test, you can try lowering the thermostat to correspond with the room. Then, wait a couple of minutes. This should make the furnace shut off momentarily.

Put in Fresh Batteries

If you have a programmable thermostat, it's likely battery powered. You can try putting in new batteries to see if that resolves 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 turn off the power.

Cut the Power

Thermostat seems to be working fine but your furnace still won't shut off? There are two places 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 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 near your furnace. Push the switch down to shut off power.
  3. Your furnace should be shut off now.

If you had to turn off your system at the breaker, call us at 912-208-2399 for professional service, as you may need furnace repair.

What Causes a Furnace to Keep Running?

Occasionally correcting this problem can be as easy as changing your air filter or adjusting thermostat settings. In other instances, you might need a professional when your heater won't shut off.

Fan Limit Switch Needs Replacing

The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, 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 an issue with the limit switch. Your furnace will communicate through a flashing red light on the front of your heating system.

Our Experts can identify and fix any issues 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.

Bad Thermostat

Like anything else 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 simple to save energy, since they create an energy-efficient heating and cooling schedule according to your preferences. Plus, you'll be able to adjust and monitor your thermostat from just about anywhere 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 constantly since the ductwork is leaking hot air in the attic.

Identifying this leaky ductwork and other airflow issues can be challenging 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 problems 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 field. You can count 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.* Contact us at 912-208-2399 to schedule your appointment now.

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