Heritage Home Service truck outside home

A broken-down gas furnace is the last problem New England homeowners want on their hands. In the dead of winter, a system that is not heating properly is truly a nightmare.

Fortunately, the solution is often as simple as restarting your furnace. It is also a great way to determine the source of the breakdown, such as a clogged filter or if it simply needed a reboot. Plus, you can do it all yourself! Keep reading, and we’ll walk you through this process, step by step.

How Do I Reset My Gas Furnace?

Before attempting to troubleshoot your furnace: If you smell a significant amount of natural gas emanating from your system, leave your home immediately and call the first department to shut off your gas. Then, contact Heritage to investigate the issue.

First, Check the Pilot Light (if you have a standing pilot system)

The initial step when troubleshooting a faulty furnace is checking whether your pilot light is lit. Inspect your pilot light by following these steps: 

  1. Open the furnace’s front panel. This will be an easily accessible, small door. 
  2. Look for a small flame. A proper pilot light is approximately a ½-inch blue flame.
  3. From here, two things could happen:
    1. If you don’t see a flame, you should re-light it and proceed to restart your furnace. Refer to the owner’s manual to properly relight your pilot light. If you’re not comfortable with doing this yourself, call us.
    2. If you see a flame, your pilot light isn’t causing furnace issues. In this case, contact us for further troubleshooting.

How to Turn the Furnace Off and On Again

Important Note: If your system is newer, it may be displaying an error code (flashing light) from the control board. There will be a small window where you may see a blinking light in a repeating pattern. Take a quick video of the pattern to help the technician if a service call is needed.

Once you inspect and relight your pilot light (if applicable), you can begin resetting your furnace. Follow the simple steps outlined below to turn your system off and on again. 

Lower the Temperature on Your Thermostat

Begin by lowering the temperature on your thermostat by a few degrees. You want the furnace to stop running. Turning the thermostat down 5 degrees below the current inside temperature should do the trick. 

Turn Off the Power


  1.  locate the breaker box for your heater, which might be in your electrical panel or in an outside unit. Be sure your hands are completely dry before touching the box. Power it off. This step will ensure the entire system is off and rebooting. 
  2. On the side of the system there should be a service switch (looks like a regular light switch). Turn off and wait before turning back on.

Bonus Step: Change Your Filter

As mentioned above, a common problem source in furnaces is a clogged or dirty filter. While the system is off, it’s a perfect time to replace the filter. 

Locate the filter in your furnace. It is commonly positioned at the top or bottom of your system. Open the access panel and slide the old filter out. Then, insert a new filter, ensuring the airflow arrows are pointed toward the furnace, and close the access panel. 

Wait, Then Turn the Power Back On

It’s important to give your system enough time to reset fully. After about ten minutes, you can restore power to the breaker. 

Check the Thermostat

Now to see if your reboot worked. Set your thermostat to heat and check your furnace’s function. If it activates and begins heating, you successfully rebooted your gas furnace and solved your problem.

Where is the Reset Switch on My Furnace?

Get to know your furnace by locating the reset button on your system. It is an important safety feature, and it can be helpful when troubleshooting a furnace issue. 

The button’s location will vary from model to model, so refer to the owner’s manual to find it. Look for a red or yellow button. It is generally located inside the blower compartment. 

When to Reboot Your Furnace

Now you have a solid grasp on restarting your furnace, but when is this necessary? Here are some instances in which a reboot is a good idea: 

  • No air is coming from the furnace. If your furnace doesn’t have any air coming out, check the pilot light and try resetting the system. 
  • The pilot light is out. When you determine the pilot light is out, proceed with the reset. This is your system’s ignition source, so relighting your pilot light and resetting your system will often resolve your issue. 
  • Not enough heat is coming out of the furnace. Is your furnace working, but barely? A clogged or dirty filter is the most likely cause, so be sure to check and change the air filter when resetting your system to solve this issue. 
  • If your system is just blowing air that is not heating, check the thermostat to make sure the fan control is in “Auto” setting. If yes then reboot your furnace.

Just Call Heritage If You’re Having Gas Furnace Troubles

What if that didn’t work? Sometimes, the problem lies in the HVAC breaker panel, or your system just won’t reboot. If you are left with a non-functional furnace, it’s time to call an HVAC company for professional help. 

We at Heritage Home Service know that getting your gas furnace up and running again is of the utmost importance as Northeasterners. We are the company homeowners in New Hampshire and Massachusetts trust for furnace repair services. Our experienced and friendly team is here to assist you and get your house heated again. Feel at home with Heritage – contact us today.