It's not unheard of for heating systems to have a glitch every now and then. It could be as straightforward as a broken thermostat or an electrical issue. If your gas furnace won't shut 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 restricts airflow, making your furnace work harder and run longer to satisfy your desired temperature.
This multiplies wear and tear on your furnace, as well as the likelihood of a malfunction and early failure.
It can also make your furnace overheat and shut down for a time to cool down. Then it will keep duplicating 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 unpleasant.
We encourage replacing flat filters each 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 dusty and you should get a new one.
If the matter was connected 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 suggest checking your thermostat settings next.
Check the Thermostat
Your thermostat controls your furnace and basically informs the unit when to turn on and off. It's often to blame when your furnace won't stop running.
Sometimes having the heat turn off is as simple 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 run when the furnace does.
“On” indicates the furnace blower will operate continuously. 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 set to "on," it will seem 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 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 greater than the room air temp, your furnace will keep operating until it hits your desired temp.
Keep in mind that if it's extremely cold outside, your furnace will have to run much longer than normal to keep your home warm. This is due to 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 probably battery powered. You can test replacing the batteries to see if that solves the issue. 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 switch 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 shut off? There are two spots you can shut off the power to your heating unit: at the breaker box and at its specific power switch.
- Head to your breaker box and find the breaker marked "furnace." Push the breaker switch to the right to shut off power.
- Next, search for the dedicated power switch to your heating system. It's similar to a light switch and can be found on or near your furnace. Push 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 925-384-1303 for professional service, as you may need furnace repair.
What Causes a Furnace to Keep Running?
Occasionally correcting this problem can be as simple as changing your air filter or adjusting thermostat settings. In other instances, you might need 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 going.
You might see a furnace error code if there's a problem with the limit switch. Your furnace will communicate through a flashing red light on the front of your heating system.
Our Experts can diagnose and correct any problems 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 you're due for a new one, ask us about getting a smart thermostat.
These thermostats make it simple to save energy, because they develop an energy-efficient heating and cooling schedule according to your preferences. Additionally, 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 throughout your home. If your home or ductwork is older, your furnace might be operating constantly since the ductwork is leaking hot air in the attic.
Diagnosing this leaky ductwork and other airflow issues can be challenging to resolve 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.
Depend on Our Experts for All Your Furnace Repair Needs
Troubleshooting furnace problems can be inconvenient, especially when it impacts your comfort, energy efficiency and heating bill. When it comes to furnaces, there's a reason why we say we're Experts in our field. 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 925-384-1303 to book your appointment now.