It's not unusual for heating systems to have a problem every now and then. It could be as simple as a broken thermostat or an electrical problem. 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 meet your desired temperature.
This increases usage on your furnace, as well as the odds of a breakdown and early failure.
It can also make your furnace overheat and shut off for a time to cool down. Then it will keep repeating this process when your furnace turns on. This is called short cycling. In addition to wearing out your furnace faster, it can drive up your heating bill and make your home feel unpleasant.
We recommend replacing flat filters each 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 dirty and you should get a new one.
If the matter was linked to a clogged air filter, replacing it with a fresh filter should solve this common problem when your heat won't turn off. If not, we recommend checking your thermostat settings next.
Check the Thermostat
Your thermostat runs your furnace and basically informs 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 includes 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 operate constantly. This constant air flow can help with heat distribution 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 sound like your furnace is not shutting off, but it's really just the furnace blower you're hearing. Switching it to "auto" should resolve the problem. It will also help you spend less money on your energy costs.
Confirm 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 running until it hits your desired temp.
Keep in mind that if it's extremely cold outside, your furnace will have to run much longer than usual to keep your home warm. This is due to a big temperature difference between the cold air outside and the warm indoors.
As a check, you can try lowering the temperature to match the room. Then, wait a few minutes. This should make the furnace turn off in a few minutes.
Replace the Batteries
If you use a programmable thermostat, it's probably battery powered. You can try putting in new batteries to see if that solves the issue. 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 switch 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 cut the power to your heating unit: at the breaker box and at its dedicated power switch.
- Go to your breaker box and find the breaker labeled "furnace." Move the breaker switch to the right to shut off power.
- Next, look for the specific power switch to your heating system. It's similar to 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 540-302-8645 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Sometimes correcting this problem can be as simple as replacing your air filter or changing 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 controls your furnace's blower motor. If the switch goes out, it might seem like your furnace running continuously, even though just the blower is running.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will communicate using a flashing red light on the front of your heating system.
Our Experts can identify and fix any issues 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 anything else 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 installing a smart thermostat.
These thermostats make it simple to save energy, since they create an energy-efficient heating and cooling schedule according to your preferences. Plus, you'll be able to adjust 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 operating constantly because the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow issues can be difficult to troubleshoot 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 annoying, 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 depend on our ACE-certified technicians to resolve 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 540-302-8645 to schedule your appointment now.