It's not uncommon for heating systems to have a problem 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 properly working furnace again.
Check the Air Filter
A dirty air filter creates problems for many homeowners and their HVAC system. Here's why. It limits airflow, making your furnace work harder and run longer to satisfy your ideal temperature.
This multiplies wear and tear on your furnace, as well as the odds of a malfunction and early failure.
It can also make your furnace overheat and shut off 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 faster, it can increase your heating bill and make your home feel unpleasant.
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 see light through your filter, it's too dirty and you should replace it.
If the matter was linked to a clogged air filter, putting in a new filter should solve this common issue when your heat won't turn off. If not, we suggest 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 usually the problem when your furnace won't stop running.
Sometimes having the heat turn off is as easy as changing a wrong thermostat setting.
Ensure 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 operate constantly. This constant air flow can help with heat distribution but will also increase 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 turning off, but it's really just the furnace blower you're hearing. Changing it to "auto" should solve the problem. It will also help you save money on your energy costs.
Check Your Temperature Setting
If your thermostat won't turn off heat, compare 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 very cold outside, your furnace will have to operate much longer than usual to keep your home cozy. This is due to a big temperature difference between the cold air outside and the warm indoors.
As a test, you can try lowering the thermostat to correspond with the room. Then, wait a few 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 try replacing the batteries to see if that resolves the problem. If it doesn't or if there's wiring to your electrical system, shift it to "off."
If your furnace won't turn 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 spots you can cut the power to your heating unit: at the breaker box and at its specific power switch.
- Go to your breaker box and find the breaker marked "furnace." Move the breaker switch to the right to shut off power.
- Next, search for the specific 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 cut power.
- Your furnace should be shut off now.
If you had to turn off your system at the breaker, call us at 239-908-6991 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Sometimes fixing this problem can be as simple as changing your air filter or changing thermostat settings. In other instances, you might want a professional when your heater won't shut off.
Fan Limit Switch Needs Replacing
The furnace fan limit switch controls 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 through 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. Often 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 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, because they develop an energy-efficient heating and cooling schedule according to your preferences. Additionally, you'll be able to set and monitor your thermostat from just about anywhere with your phone.
Leaky Air Ducts
Your furnace relies on ductwork to circulate hot air to vents throughout your home. If your home or ductwork is older, your furnace might be operating all the time since the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow problems can be tricky 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 inconvenient, 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 depend 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 239-908-6991 to book your appointment now.