It's not uncommon for heating systems to have a glitch every now and then. It could be as straightforward as a bad thermostat or an electrical issue. If your gas furnace won't shut off, here are a couple steps you can take to get a properly working furnace again.
Check the Air Filter
A dirty air filter causes problems 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 multiplies wear and tear 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 off for a time to cool down. Then it will keep duplicating 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 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 replace it.
If the matter was linked to a clogged air filter, replacing it with a fresh filter should fix this common issue when your heat won't turn off. If not, we recommend checking your thermostat settings next.
Check Out the Thermostat
Your thermostat controls 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.
Sometimes having the heat turn off is as simple as adjusting an incorrect 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” means the furnace blower will only run when the furnace does.
“On” means the furnace blower will run constantly. This constant air flow can help with heat circulation but will also increase your power bill and lead to wear and tear on your furnace.
If your thermostat is set 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 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 very cold outside, your furnace will have to run much longer than normal 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 thermostat to match the room. Then, wait a couple of 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 test putting in new batteries to see if that resolves the issue. 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 set 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 shut off the power to your heating unit: at the breaker box and at its dedicated power switch.
- Head 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 specific power switch to your heating system. It looks like a light switch and can be found on or close to 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, call us at 713-396-3760 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Occasionally fixing this problem can be as easy as changing your air filter or changing thermostat settings. In other situations, you might want a professional when your heater won't turn off.
Fan Limit Switch Needs to Be Replaced
The furnace fan limit switch controls your furnace's blower motor. If the switch goes bad, it might seem like your furnace running continuously, 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 speak through a blinking red light on the front of your heating system.
Our Experts can diagnose and fix any issues you're having with your furnace blower motor. Sometimes 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 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 according to your needs. Plus, you'll be able to adjust and monitor your thermostat from just about anywhere with your phone.
Air Ducts Are Leaking
Your furnace relies on 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.
Diagnosing this leaky ductwork and other airflow problems can be challenging to resolve on your own, since it's concealed 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 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 rely 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.* Call us at 713-396-3760 to schedule your appointment now.