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 straightforward as a broken thermostat or an electrical problem. If your gas furnace won't shut 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 numerous 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 multiplies wear and tear on your furnace, as well as the odds of a malfunction and premature failure.

It can also make your furnace get too hot and shut down for a time to cool down. Then it will keep repeating this process when your furnace turns on. This is known as 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 monthly 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 detect light through your filter, it's too dirty and you should get a new one.

If the matter was connected to a clogged air filter, putting in a new filter should fix this common issue when your heat won't turn off. If not, we recommend 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 usually the problem 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 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 constantly. This constant air flow can help with heat circulation but will also drive up 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 shutting 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 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 area temperature. If it's greater than the room air temp, your furnace will keep running 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 warm. This is due to a large temperature difference between the cold air outside and the warm indoors.

As a test, you can try lowering the setting to match the room. Then, wait a few minutes. This should make the furnace turn 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 resolves 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 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 places you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch.

  1. Go to your breaker box and find the breaker marked "furnace." Move the breaker switch to the right to cut power.
  2. Next, search for the dedicated 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.
  3. Your furnace should be turned off now.

If you had to switch off your system at the breaker, contact us at 303-647-5853 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 replacing your air filter or changing thermostat settings. In other situations, you might want a professional when your heater won't turn 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 speak using 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, like the control board, faulty wiring or the fan switch itself.

Defective Thermostat

Like anything else in your home, your thermostat can break down 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 easy to save energy, since they develop an energy-efficient heating and cooling schedule according to your needs. Additionally, you'll be able to adjust and keep tabs on your thermostat from just about anyplace 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 constantly because 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 concealed behind walls and ceilings. Our Experts can help with diagnosing and taking care of any air duct repair service that you need.

Depend on Our Experts for All Your Furnace Repair Needs

Troubleshooting furnace issues can be annoying, especially when it impacts your comfort, energy efficiency and heating bill. When it involves 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 303-647-5853 to book your appointment today.

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