It's not unusual for heating systems to have a problem once in a while. It could be as simple as a bad thermostat or an electrical issue. If your gas furnace won't turn off, here are a couple steps you can take to get a correctly working furnace again.
Examine the Air Filter
A dirty air filter creates problems for numerous homeowners and their HVAC system. Here's why. It restricts 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 early failure.
It can also make your furnace overheat and shut down 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 more quickly, it can drive up your heating bill and make your home feel uncomfortable.
We recommend replacing flat filters once a month 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 dirty and you should get a new one.
If the matter was connected to a clogged air filter, putting in a new filter should fix 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 simply tells 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 simple as changing an incorrect 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 operate when the furnace does.
“On” indicates the furnace blower will run 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 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 higher than the room air temp, your furnace will keep running until it hits your desired temp.
Keep in mind that if it's extremely cold outside, your furnace will have to operate 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 check, you can try lowering the thermostat to match 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 use a programmable thermostat, it's probably battery powered. You can test replacing the batteries to see if that solves the issue. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't shut off after you switch it to "off," you will need to cut the power.
Turn Off the Power
Thermostat seems to be working fine but your furnace still won't shut off? There are two places 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 find the breaker marked "furnace." Move the breaker switch to the right to cut 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. 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 289-201-2346 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Occasionally fixing this problem can be as simple as replacing your air filter or changing thermostat settings. In other instances, you might want a professional when your heater won't turn 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 going.
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 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. Plus, you'll be able to set and keep tabs on your thermostat from just about anyplace with your phone.
Air Ducts Are Leaking
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 constantly because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow issues can be challenging to resolve on your own, since it's hidden behind walls and ceilings. Our Experts can help with diagnosing and handling any air duct repair service that you need.
Depend 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 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.* Call us at 289-201-2346 to schedule your appointment today.