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

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

Check the Air Filter 

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

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

It can also make your furnace get too hot and shut off for a time to cool down. Then it will keep repeating 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 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, putting in a fresh filter should solve this common problem 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 simply tells the unit when to turn on and off. It’s often the problem when your furnace won’t stop running. 

Sometimes having the heat turn off is as simple as adjusting an incorrect thermostat setting. 

Ensure 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 run 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 shutting off, but it’s really just the furnace blower you’re noticing. Switching 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 area temperature. If it’s higher 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 warm. 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 temperature to correspond with the room. Then, wait a few minutes. This should make the furnace shut off in a few minutes. 

Put in New Batteries 

If you use a programmable thermostat, it’s probably battery powered. You can try putting in new 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 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 places you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch. 

  1. Head to your breaker box and locate the breaker labeled “furnace.” Move the breaker switch to the right to shut off power. 
  1. Next, look for the dedicated power switch to your heating system. It’s similar to a light switch and can be found 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 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 fixing this problem can be as simple 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 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 diagnose 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. 

Faulty Thermostat 

Like other things in your home, your thermostat can wear out 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 easy to save energy, since they create an energy-efficient heating and cooling schedule based on 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 relies on ductwork to distribute hot air to vents throughout 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. 

Diagnosing this leaky ductwork and other airflow problems can be tricky 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 need. 

Depend on Our Experts for All Your Furnace Repair Needs 

Troubleshooting furnace problems can be annoying, especially 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.* Call us at 866-397-3787 to book your appointment today. 

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