What to Do When Your Heater Wont Turn Off!

It's not unusual for heating systems to have a problem once in a while. It could be as straightforward 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 properly working furnace again.

Check the Air Filter

A dirty air filter causes issues for numerous 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 wear and tear on your furnace, as well as the likelihood of a malfunction and early failure.

It can also make your furnace overheat and shut down for a time to cool down. Then it will keep duplicating this process when your furnace switches on. This is known as short cycling. In addition to wearing out your furnace more quickly, it can increase your heating bill and make your home feel unpleasant.

We recommend 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 linked to a clogged air filter, replacing it with 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 simply tells the unit when to turn on and off. It's often to blame when your furnace won't stop running.

At times having the heat turn off is as easy as changing a wrong thermostat setting.

Make Sure 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 run when the furnace does.

“On” indicates the furnace blower will run constantly. 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 set 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 resolve 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, check the temperature setting to the room temperature. If it's higher than the room air temp, your furnace will keep running until it hits your desired temp.

Remember that if it's extremely 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 decreasing the setting to match the room. Then, wait a couple of minutes. This should make the furnace shut off momentarily.

Put in Fresh Batteries

If you use a programmable thermostat, it's likely battery powered. You can test replacing the batteries to see if that resolves the problem. If it doesn't or if there's wiring to your electrical system, switch it to "off."

If your furnace won't shut off after you set it to "off," you will need to turn off the power.

Cut the Power

Thermostat appears to be working fine but your furnace still won't shut off? There are two places you can cut the power to your heating unit: at the breaker box and at its dedicated power switch.

  1. Head to your breaker box and find the breaker marked "furnace." Push the breaker switch to the right to shut off power.
  2. Next, look for the dedicated power switch to your heating system. It's similar to a light switch and is located on or close to your furnace. Move the switch down to cut power.
  3. Your furnace should be turned off now.

If you had to turn off your system at the breaker, call us at 866-397-3787 for professional service, as you may need furnace repair.

What Causes a Furnace to Keep Running?

Sometimes correcting this problem can be as easy as replacing 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 to Be Replaced

The furnace fan limit switch controls your furnace's blower motor. If the switch goes out, it might sound like your furnace running continuously, 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 fix 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.

Defective Thermostat

Like other things 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 simple to save energy, since they create an energy-efficient heating and cooling schedule according to your needs. Additionally, you'll be able to adjust and monitor your thermostat from just about anyplace with your phone.

Leaky Air Ducts

Your furnace relies on ductwork to circulate hot air to vents throughout 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.

Diagnosing this leaky ductwork and other airflow issues can be challenging to resolve on your own, since it's concealed 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, especially when it affects 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 rely 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.* Contact us at 866-397-3787 to book your appointment now.

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