It's not uncommon 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 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 limits airflow, making your furnace work harder and run longer to satisfy 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 down. Then it will keep repeating this process when your furnace switches on. This is known as 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 once a month and pleated filters every three months. If you can't remember the last time you replaced your furnace filter, pull it out and hold it up to the light. If you can't see light through your filter, it's too dusty and you should get a new one.
If the matter was connected to a clogged air filter, putting in a clean 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 controls your furnace and simply informs 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 has 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 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 seem like your furnace is not turning off, but it's really just the furnace blower you're noticing. 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, compare the temperature setting to the area temperature. If it's greater than the room air temp, your furnace will keep operating until it hits 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 cozy. This is because of a large temperature difference between the cold air outside and the warm indoors.
As a check, you can try decreasing the temperature to match the room. Then, wait a couple of minutes. This should make the furnace turn off momentarily.
Replace the Batteries
If you use a programmable thermostat, it's probably 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, shift it to "off."
If your furnace won't shut off after you move it to "off," you will need to turn off the power.
Cut the Power
Thermostat appears to be working fine but your furnace still won't turn off? There are two spots 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 locate the breaker marked "furnace." Move the breaker switch to the right to shut off power.
- Next, look for the dedicated 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 switch off your system at the breaker, call us at 925-364-5427 for professional service, as you may require furnace repair.
What Causes a Furnace to Keep Running?
Occasionally correcting this problem can be as easy as changing your air filter or adjusting thermostat settings. In other instances, you might want a professional when your heater won't shut 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 seem like your furnace running nonstop, even though just the blower is running.
You might see a furnace error code if there's a problem with the limit switch. Your furnace will communicate using a blinking 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. Sometimes this can involve replacement parts, like the control board, faulty wiring or the fan switch itself.
Faulty Thermostat
Like anything else in your home, your thermostat can wear out 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, since they create an energy-efficient heating and cooling schedule according to your preferences. Additionally, you'll be able to adjust and keep tabs on your thermostat from just about anyplace with your phone.
Leaky Air Ducts
Your furnace uses ductwork to distribute hot air to vents across 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.
Identifying this leaky ductwork and other airflow issues can be challenging to troubleshoot 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.
Rely 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 industry. You can count on our ACE-certified technicians to solve 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 925-364-5427 to schedule your appointment today.