It's not unusual for heating systems to have a problem once in a while. It could be as straightforward 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.
Examine the Air Filter
A dirty air filter causes problems for many 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 multiplies usage on your furnace, as well as the odds of a breakdown and premature failure.
It can also make your furnace get too hot 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 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, 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 fresh filter should solve this common problem 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 basically tells the unit when to turn on and off. It's often the problem 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” means the furnace blower will only operate when the furnace does.
“On” means the furnace blower will operate continuously. This constant air flow can help with heat circulation 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 shutting off, but it's really just the furnace blower you're noticing. 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 room temperature. If it's higher than the room air temp, your furnace will keep operating until it reaches your desired temp.
Remember that if it's extremely cold outside, your furnace will have to run 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 test, you can try reducing the setting to match the room. Then, wait a few minutes. This should make the furnace shut off in a few minutes.
Put in Fresh Batteries
If you use a programmable thermostat, it's likely battery powered. You can try 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 turn off after you move it to "off," you will need to turn off the power.
Turn Off the Power
Thermostat seems 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 labeled "furnace." Push the breaker switch to the right to shut off power.
- Next, look for the dedicated power switch to your heating system. It looks like a light switch and can be found on or near your furnace. Move the switch down to cut power.
- Your furnace should be turned off now.
If you had to switch off your system at the breaker, contact us at 561-629-1826 for professional service, as you may need 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 situations, you might want 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 seem like your furnace running continuously, even though just the blower is going.
You might notice a furnace error code if there's a problem with the limit switch. Your furnace will speak 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 other things in your home, your thermostat can break down over time and need to be replaced. If it's time 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 needs. Additionally, you'll be able to adjust 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 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.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems 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 field. You can rely 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 561-629-1826 to schedule your appointment now.