It's not uncommon for heating systems to have a problem every now and then. It could be as straightforward as a broken thermostat or an electrical issue. If your gas furnace won't shut off, here are a couple 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 limits airflow, making your furnace work harder and run longer to satisfy your desired temperature.
This multiplies usage on your furnace, as well as the likelihood of a malfunction 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 duplicating 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 uncomfortable.
We encourage replacing flat filters monthly and pleated filters every three months. If you can't remember the last time you got a new furnace filter, pull it out and hold it up to the light. If you can't detect light through your filter, it's too dusty and you should replace it.
If the matter was linked to a clogged air filter, putting in 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 basically 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 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” indicates 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 circulation but will also drive up your power bill and increase 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 spend less money on your energy costs.
Check Your Temperature Setting
If your thermostat won't turn off heat, check 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.
Keep in mind that if it's extremely cold outside, your furnace will have to run much longer than normal to keep your home cozy. 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 setting to match the room. Then, wait a couple of minutes. This should make the furnace shut off in a few minutes.
Put in New Batteries
If you have a programmable thermostat, it's likely battery powered. You can test 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 set it to "off," you will need to cut the power.
Turn Off the Power
Thermostat appears 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 labeled "furnace." Move the breaker switch to the right to cut power.
- Next, look for the specific power switch to your heating system. It looks like a light switch and is located on or close to your furnace. Move the switch down to cut power.
- Your furnace should be shut off now.
If you had to switch off your system at the breaker, call us at 816-787-0500 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 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 sound like your furnace running continuously, even though just the blower is running.
You might notice a furnace error code if there's an issue 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 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 other things in your home, your thermostat can wear out over time and need to be replaced. If it's time for a new one, ask us about installing a smart thermostat.
These thermostats make it simple to save energy, since they develop 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 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 operating all the time because the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow issues 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 problems can be inconvenient, particularly 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 industry. 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 816-787-0500 to schedule your appointment now.