It's not uncommon for heating systems to have a problem once in a while. It could be as straightforward as a broken thermostat or an electrical problem. If your gas furnace won't turn 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 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 multiplies wear and tear on your furnace, as well as the odds of a breakdown and premature failure.
It can also make your furnace get too hot and shut off for a time to cool off. 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 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 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 dusty and you should get a new one.
If the matter was connected to a clogged air filter, replacing it with a new filter should solve 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 runs your furnace and simply informs the unit when to turn on and off. It's usually 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.
Ensure Your Thermostat is Set to “Auto”
Your thermostat includes two settings, “auto” and “on,” that control 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 turning 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 room temperature. If it's higher than the room air temp, your furnace will keep operating until it hits your desired temp.
Keep in mind 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 check, you can try lowering the setting to match the room. Then, wait a couple of minutes. This should make the furnace turn off in a few minutes.
Put in New Batteries
If you use a programmable thermostat, it's probably battery powered. You can try replacing the batteries to see if that resolves the issue. 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 switch 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 shut off? There are two spots you can cut the power to your heating unit: at the breaker box and at its dedicated power switch.
- Head to your breaker box and find the breaker labeled "furnace." Push the breaker switch to the right to shut off power.
- Next, look for the specific power switch to your heating system. It looks like a light switch and can be found on or close to your furnace. Move the switch down to shut off power.
- Your furnace should be turned off now.
If you had to switch off your system at the breaker, call us at 727-219-2471 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 situations, you might need 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 out, it might sound like your furnace running continuously, even though just the blower is going.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will speak via a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any problems 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.
Like anything else in your home, your thermostat can break down as time passes and need to be replaced. If it's time 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 based on your needs. Additionally, you'll be able to set and keep tabs on your thermostat from just about anywhere with your phone.
Leaky Air Ducts
Your furnace uses ductwork to distribute hot air to vents across 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 problems can be difficult to troubleshoot 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 annoying, particularly 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 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 727-219-2471 to schedule your appointment today.