It's not unusual for heating systems to have a glitch once in a while. 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 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 restricts airflow, making your furnace work harder and run longer to meet your ideal 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 down for a time to cool off. Then it will keep repeating 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, remove it and hold it up to the light. If you can't detect 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 new filter should solve 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 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 easy as adjusting a wrong 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” indicates the furnace blower will operate continuously. This constant air flow can help with heat distribution 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 seem like your furnace is not turning off, but it's really just the furnace blower you're noticing. 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.
Remember that if it's very cold outside, your furnace will have to operate much longer than usual 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 lowering the temperature to match the room. Then, wait a couple of minutes. This should make the furnace shut off momentarily.
Put in Fresh 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 shut off after you set 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 shut off? There are two places 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 locate the breaker marked "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. Push the switch down to cut power.
- Your furnace should be turned off now.
If you had to turn off your system at the breaker, call us at 484-401-7577 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Sometimes fixing this problem can be as easy as replacing your air filter or adjusting thermostat settings. In other situations, you might need a professional when your heater won't shut off.
Fan Limit Switch Needs Replacing
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 communicate via a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any issues you're having with your furnace blower motor. Often this can involve replacement parts, such as the control board, faulty wiring or the fan switch itself.
Like anything else in your home, your thermostat can break down as time passes 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, because they create an energy-efficient heating and cooling schedule based on your preferences. Additionally, you'll be able to adjust and monitor your thermostat from just about anyplace with your phone.
Air Ducts Are Leaking
Your furnace uses ductwork to circulate hot air to vents across your home. If your home or ductwork is older, your furnace might be running constantly since the ductwork is leaking hot air in the attic.
Identifying this leaky ductwork and other airflow problems can be difficult to resolve on your own, since it's hidden behind walls and ceilings. Our Experts can help with identifying and handling 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 involves 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.* Contact us at 484-401-7577 to book your appointment today.