It's not unheard of for heating systems to have a glitch 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 few steps you can take to get a correctly working furnace again.
Examine the Air Filter
A dirty air filter creates issues for many homeowners and their HVAC system. Here's why. It limits airflow, forcing your furnace to work harder and run longer to satisfy your ideal temperature.
This increases usage on your furnace, as well as the odds of a breakdown and early failure.
It can also make your furnace overheat and shut off for a time to cool off. Then it will keep repeating this process when your furnace switches on. This is called short cycling. In addition to wearing out your furnace faster, it can drive up your heating bill and make your home feel uncomfortable.
We encourage replacing flat filters each 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 replace it.
If the matter was connected 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 recommend 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.
At times having the heat turn off is as simple as changing a wrong thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that manage your heating system's blower motor.
“Auto” means the furnace blower will only run when the furnace does.
“On” indicates 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 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, compare the temperature setting to the room temperature. If it's greater than the room air temp, your furnace will keep operating until it reaches your desired temp.
Remember that if it's extremely cold outside, your furnace will have to run much longer than normal 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 reducing the thermostat to correspond with the room. Then, wait a couple of minutes. This should make the furnace shut off in a few minutes.
Replace the Batteries
If you have 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 move it to "off," you will need to turn off the power.
Turn Off the Power
Thermostat seems to be working fine but your furnace still won't turn off? There are two spots you can shut off the power to your heating unit: at the breaker box and at its dedicated power switch.
- Head to your breaker box and locate the breaker marked "furnace." Move the breaker switch to the right to shut off power.
- Next, search for the specific power switch to your heating system. It's similar to a light switch and can be found on or close to your furnace. Push the switch down to cut power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, contact us at 904-450-5672 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 adjusting thermostat settings. In other instances, you might want a professional when your heater won't turn off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes bad, it might seem like your furnace running nonstop, even though just the blower is going.
You might see a furnace error code if there's a problem with the limit switch. Your furnace will speak through a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any issues you're having with your furnace blower motor. Often this can involve replacement parts, such as the control board, faulty wiring or the fan switch itself.
Like other things in your home, your thermostat can wear out as time passes and need to be replaced. If it's time for a new one, ask us about installing a smart thermostat.
These thermostats make it easy to save energy, because they develop an energy-efficient heating and cooling schedule based on your needs. Plus, you'll be able to set and monitor your thermostat from just about anyplace 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.
Diagnosing this leaky ductwork and other airflow problems can be challenging to resolve 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 require.
Rely on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace issues can be annoying, particularly 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 solve 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 904-450-5672 to book your appointment today.