If you are currently shivering and wondering where is the reset button on a furnace, it's almost always located inside the blower compartment, usually right on or near the motor itself. It's designed to be a little bit hidden because it's a safety feature, not something you're supposed to be toggling every day. Most of the time, it's a small, bright red or yellow button that's pretty easy to spot once you've pulled the access panel off.
It is incredibly frustrating when the heat cuts out on a cold night. You head down to the basement or over to the utility closet, hear nothing but silence, and realize the house is getting colder by the minute. Before you start panicking about the cost of a brand-new HVAC system, finding that reset button is usually the first "DIY" step every homeowner takes. Think of it like a circuit breaker for your furnace; it's there to shut things down before something actually breaks or, worse, becomes a fire hazard.
Finding the Hidden Switch
To get to the button, you're going to have to do a little bit of manual labor, but nothing too crazy. First things first: make sure the power to the furnace is turned off at the side switch or the breaker box. You don't want to be poking around near a blower motor while it has the potential to kick on.
Once the power is off, look for the main access panel on the front of the unit. This is usually the large metal door that covers the blower and the motor. Some panels just lift off, while others might have a couple of thumb screws or require a screwdriver. Once you pop that panel off, peek inside. You are looking for the blower motor, which is the big circular housing that looks a bit like a squirrel cage. On the side of that motor housing, or sometimes on a small control box attached to it, you'll see that small red button.
If you don't see it there, check the side of the burner assembly. In some older models or specific brands, the reset might be located near the ignition control. But nine times out of ten, it's right there on the blower motor waiting for you.
Why Did It Trip in the First Place?
It's tempting to just hit the button and walk away once you hear the flames roar back to life. But the reality is that the reset button tripped for a reason. It's a safety mechanism called a "lockout." It's telling you that the furnace tried to do its job, sensed something was wrong, and decided to quit for your own protection.
One of the most common reasons is that the furnace overheated. This usually happens because of a lack of airflow. If your air filter is packed with dust, pet hair, and dander, the blower has to work twice as hard to pull air through. The heat builds up inside the cabinet, the sensors get spooked, and pop—the reset button trips. If you find the button has popped, the very next thing you should do is check that filter. If it looks like a thick wool rug, toss it and get a clean one.
Another reason could be a "flame out" or a failure to ignite. If the furnace tried to start up but the gas didn't light, or if the sensor didn't detect the flame, it shuts down so it doesn't just keep pumping gas into your house. That's a pretty important job for a little red button to have.
How to Properly Reset the Unit
Once you've found where is the reset button on a furnace, don't just mash it repeatedly. There is a bit of a technique to doing it safely.
- Power Down: As mentioned, hit the service switch (it looks like a light switch on the side of the furnace) or flip the breaker.
- Cool Down: If the unit tripped because it overheated, give it a good 20 to 30 minutes to cool off. If you try to reset it while it's still piping hot, it'll likely just trip again immediately.
- The Press: Push the button in. You should feel a distinct "click." If the button feels mushy or doesn't stay in, it might not have been tripped, or the unit might still be too hot.
- Power Up: Put the panel back on (some furnaces have a safety switch that won't let them run if the door is off), and turn the power back on.
- Listen: Head to your thermostat, crank it up, and listen. You want to hear the inducer motor start, then the click of the igniter, and finally the "whoosh" of the burners.
The Three-Strike Rule
Here is the most important part: do not reset your furnace more than once or twice. If you push that button and the furnace runs for five minutes and then trips again, you have a real problem. Continuing to hit the reset button is like ignoring a fire alarm by taking the batteries out.
If you keep forcing it to restart, you could be pumping unburned oil (in oil furnaces) or gas into the combustion chamber. This can lead to a "puff back" or a small explosion when it finally does ignite, which is a great way to turn a $200 repair into a $5,000 replacement. If it trips a second time shortly after the first, it's time to put the screwdriver down and call a pro. It could be a bad thermocouple, a cracked heat exchanger, or a failing motor—none of which are things you want to mess with if you aren't a licensed tech.
Keeping the Button from Popping Again
The best way to avoid searching for where is the reset button on a furnace in the middle of a blizzard is a little bit of preventitive maintenance. Most of the time, these lockouts are caused by simple things we forget to do.
- Change those filters: I know I already mentioned it, but I can't stress it enough. A clean filter is the lungs of your HVAC system. Change it every 1-3 months.
- Keep vents open: You might think you're saving money by closing vents in rooms you don't use, but that actually increases the pressure and heat inside your furnace. Keep at least 80% of your registers open to maintain proper airflow.
- Check the exhaust: Make sure the PVC pipes or the chimney venting the exhaust aren't blocked by snow, ice, or a stray bird's nest. If the exhaust can't get out, the furnace will shut down immediately.
- Clean the flame sensor: If you're a bit more handy, cleaning the flame sensor with a bit of emery cloth once a year can prevent "false" trips where the furnace thinks there's no flame even when there is.
Wrapping It Up
Finding where is the reset button on a furnace is a handy skill for any homeowner, and it can save you from an expensive "no-heat" call on a weekend or holiday. Just remember that the button is a messenger. It's telling you that something isn't quite right. Respect the "click," check your filters, and don't be afraid to call in the experts if the furnace keeps acting up. Stay warm and stay safe!