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

It’s not unusual for heating systems to have a glitch 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 couple steps you can take to get a correctly working furnace again. 

Check the Air Filter 

A dirty air filter causes issues for many homeowners and their HVAC system. Here’s why. It limits airflow, making your furnace work harder and run longer to meet your desired temperature. 

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

It can also make your furnace overheat and shut off for a time to cool off. 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 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 replaced your furnace filter, remove it and hold it up to the light. If you can’t see light through your filter, it’s too dirty and you should replace it. 

If the matter was linked to a clogged air filter, replacing it with a new filter should fix this common problem when your heat won’t turn off. If not, we suggest checking your thermostat settings next. 

Check 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. 

Sometimes having the heat turn off is as simple as changing a wrong 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” means the furnace blower will only operate when the furnace does. 

“On” indicates the furnace blower will run 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 shutting 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 save 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 higher 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 normal to keep your home warm. This is because of a big temperature difference between the cold air outside and the warm indoors. 

As a check, you can try lowering the setting to match the room. Then, wait a few minutes. This should make the furnace shut off in a few minutes. 

Put in Fresh Batteries 

If you use a programmable thermostat, it’s likely battery powered. You can try replacing the batteries to see if that solves 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 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 turn off? There are two places you can cut the power to your heating unit: at the breaker box and at its specific power switch. 

  1. Head to your breaker box and find the breaker labeled “furnace.” Push the breaker switch to the right to cut power. 
  1. Next, look 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 shut off power. 
  1. Your furnace should be shut off now. 

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

What Causes a Furnace to Keep Running? 

Occasionally correcting this problem can be as simple as changing your air filter or changing thermostat settings. In other situations, you might want 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 seem like your furnace running continuously, even though just the blower is running. 

You might see a furnace error code if there’s an issue with the limit switch. Your furnace will communicate via a blinking 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. Sometimes this can involve replacement parts, like the control board, faulty wiring or the fan switch itself. 

Faulty 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 installing a smart thermostat

These thermostats make it simple to save energy, because they develop 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 anyplace with your phone. 

Leaky Air Ducts 

Your furnace relies on ductwork to distribute hot air to vents across your home. If your home or ductwork is older, your furnace might be operating constantly since the ductwork is leaking hot air in the attic. 

Diagnosing this leaky ductwork and other airflow problems can be tricky to resolve on your own, since it’s hidden behind walls and ceilings. Our Experts can help with diagnosing and taking care of any air duct repair service that you require. 

Rely on Our Experts for All Your Furnace Repair Needs 

Troubleshooting furnace issues 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 depend on our ACE-certified technicians to resolve your problem quickly and affordably. And what’s even better, we back our HVAC system repairs with a 100% satisfaction guarantee for one year.* Contact us at 866-397-3787 to book your appointment today. 

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