It's not unusual for heating systems to have a glitch every now and then. It could be as simple as a broken thermostat or an electrical issue. 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 numerous homeowners and their HVAC system. Here's why. It restricts 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 likelihood of a breakdown and early failure.
It can also make your furnace overheat and shut down 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 increase your heating bill and make your home feel unpleasant.
We encourage 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 fix 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 the problem when your furnace won't stop running.
At times having the heat turn off is as easy as changing an incorrect 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” means the furnace blower will only operate when the furnace does.
“On” means 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 sound like your furnace is not turning off, but it's really just the furnace blower you're noticing. Switching 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.
Remember that if it's very cold outside, your furnace will have to operate much longer than usual to keep your home cozy. This is because of a large temperature difference between the cold air outside and the warm indoors.
As a test, you can try lowering the thermostat to match the room. Then, wait a couple of minutes. This should make the furnace turn off momentarily.
Replace the Batteries
If you use a programmable thermostat, it's likely battery powered. You can test replacing the 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 move it to "off," you will need to turn off the power.
Cut 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.
- Go to your breaker box and locate 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 is located on or near your furnace. Push the switch down to shut off power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, call us at 226-270-1164 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting this problem can be as easy as replacing your air filter or changing thermostat settings. In other instances, you might need a professional when your heater won't turn off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, it might sound 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 through a flashing 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, like the control board, faulty wiring or the fan switch itself.
Like other things in your home, your thermostat can break down 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 develop an energy-efficient heating and cooling schedule based on your preferences. Plus, you'll be able to set and keep tabs on your thermostat from just about anywhere with your phone.
Air Ducts Are Leaking
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 because the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow problems can be challenging to troubleshoot on your own, since it's hidden behind walls and ceilings. Our Experts can help with identifying and taking care of any air duct repair service that you need.
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 industry. 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 226-270-1164 to book your appointment now.