It's not uncommon 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 few steps you can take to get a correctly working furnace again.
Examine 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 early 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 turns 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 unpleasant.
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, pull it out 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 clean filter should solve this common issue when your heat won't turn off. If not, we suggest checking your thermostat settings next.
Check the Thermostat
Your thermostat runs your furnace and basically 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 adjusting an incorrect thermostat setting.
Make Sure Your Thermostat is Set to “Auto”
Your thermostat has two settings, “auto” and “on,” that control your heating system's blower motor.
“Auto” indicates the furnace blower will only operate when the furnace does.
“On” means the furnace blower will run continuously. This constant air flow can help with heat circulation 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 sound like your furnace is not shutting off, but it's really just the furnace blower you're hearing. Changing it to "auto" should resolve 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 area temperature. If it's greater 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 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 reducing the setting to correspond with the room. Then, wait a couple of minutes. This should make the furnace turn off in a few minutes.
Put in Fresh Batteries
If you have a programmable thermostat, it's likely battery powered. You can test putting in new batteries to see if that resolves the issue. 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 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 turn off? There are two spots you can cut the power to your heating unit: at the breaker box and at its specific power switch.
- Head to your breaker box and find the breaker marked "furnace." Move the breaker switch to the right to cut power.
- Next, search 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.
- Your furnace should be turned off now.
If you had to turn off your system at the breaker, call us at 605-223-0307 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Occasionally correcting this problem can be as simple as replacing your air filter or adjusting thermostat settings. In other instances, you might want a professional when your heater won't shut off.
Fan Limit Switch Needs to Be Replaced
The furnace fan limit switch regulates your furnace's blower motor. If the switch goes out, it might sound like your furnace running nonstop, 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 speak using a blinking red light on the front of your heating system.
Our Experts can identify and fix any problems you're having with your furnace blower motor. Sometimes 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 over time and need to be replaced. If you're due for a new one, ask us about getting 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. Plus, you'll be able to adjust and keep tabs on your thermostat from just about anyplace 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 all the time because the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow issues can be challenging to resolve on your own, since it's concealed behind walls and ceilings. Our Experts can help with identifying 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 impacts 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 solve 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 605-223-0307 to book your appointment now.