How To Reset A Gas Furnace

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Furnace issues can always seem difficult to troubleshoot, especially for those with little to no HVAC experience. If your gas furnace is acting up, it may need to be reset. The question is, how do you reset a gas furnace? We did the research to bring you the answer.

In order to reset a gas furnace, follow the steps below:

  1. Turn off the pilot light.
  2. Power off the thermostat.
  3. Turn off the breaker that powers the furnace.
  4. Turn off the main gas supply to the furnace but leave the pilot light gas supply on.
  5. Relight the pilot light.
  6. Turn on the breaker and main gas supply.
  7. Locate the reset button and press it for 30 seconds.
  8. Let the furnace restart and turn on the thermostat.
  9. Set the thermostat to the desired temperature.
  10. Check that the furnace is working properly.

While it isn't rocket science, resetting a gas furnace can be intimidating if you have never done it before. Not to worry, though; in this article, we will discuss each step in detail to make sure that you reset your gas furnace correctly the first time. In addition, we will answer other frequently asked questions about gas furnaces, so keep reading!

A dirty and old gas furnace ready for cleaning and maintenance, How To Reset A Gas Furnace

Resetting A Gas Furnace

A gas furnace uses a flame to heat air that dissipates heat around the house. A pilot light ignites the burners inside the furnace, which heats the air.

The air circulates through a series of ducts and vents around the house and is pushed out into each room through registers in the floor, ceiling, or walls.

If your furnace isn't working properly, it may need to be reset. All you need to do to reset the furnace is follow these simple steps:

Goodman furnace placed next to a boiler and air humidifier duct in a boiler room

1. Turn Off Pilot Light

The pilot light is a small flame that ignites the main burner. In order to reset your gas furnace, you will need to turn off the pilot light. To do this, simply find the knob near the bottom of your furnace and turn it to the "off" position.

2. Power Off Thermostat

The thermostat controls the furnace's temperature. In order to reset your furnace, you will need to turn off the thermostat by flipping the switch to the "off" position.

3. Turn Off Breaker

The breaker powers the furnace. In order to reset your gas furnace, you will need to turn off the breaker that powers the furnace. This can usually be found in the fuse box or breaker box.

Your breaker box has a chart that will tell you which breaker powers which appliance in your house. Once you find the breaker that powers the furnace, simply flip the switch to the "off" position.

4. Turn Off Main Gas Supply But Leave Pilot Light Gas Supply On

The main gas supply is what powers the furnace. In order to reset your gas furnace, you will need to turn off the main gas supply but leave the pilot light gas supply on.

Find the knob that controls the main gas supply and turn it to the "off" position. You will usually find this by your gas meter in your home. 

5. Relight Pilot Light

Once you have turned off the main gas supply, you can relight the pilot light. First, find the knob that controls the pilot light gas supply and turn it to the "on" position.

Then, use a match or lighter to ignite the pilot light. Some furnaces will have a built-in igniter that you can use to light the pilot light.

6. Turn On Breaker And Main Gas Supply

Now that the pilot light is lit, you can turn on the breaker and main gas supply. It doesn't matter which order you turn them on. 

7. Locate Reset Button And Press It For 30 Seconds

The final step is to locate the reset button and press it for 30 seconds. The reset button is usually located in the blower compartment of the furnace.

8. Turn On The Thermostat

After pressing the reset button for 30 seconds, the furnace should restart and turn on.

9. Set Thermostat To Desired Temperature

Once the furnace has been reset, you can set the thermostat to the desired temperature.

10. Check That The Furnace Is Working Properly

Your gas furnace is now reset and should be working properly. If you have any further questions or concerns, be sure to consult your furnace's owner's manual.

If you are still having issues with your furnace, you may need to call a professional for assistance.

What Could Cause A Gas Furnace Not To Kick On?

A few different things could cause a gas furnace not to kick on. Let's look at the most common reasons why this is happening to help troubleshoot this issue.

Worker checking the furnace for any damages or any wiring cuts

Tripped Breaker

The most common reason for a gas furnace not kicking on is that the breaker has been tripped. If you have checked the breaker box and found that the switch for the furnace breaker is in the "off" position, simply flip it to the "on" position and see if this fixes the problem.

If the breaker trips again, there may be an issue with the furnace itself, and you will need to call a professional for assistance. In addition, you could be having an issue with the power supply to the furnace.

Out Of Gas

Another common reason for a gas furnace not kicking on is that there is no longer any gas in the tank. This can happen if you have run out of gas or if there is a leak in the gas line. If you think this may be the case, you will need to call your gas company for assistance.

Dirty Filter

A dirty filter can also prevent a gas furnace from kicking on. If the filter is too clogged, it can restrict the airflow to the furnace and cause it to shut down. To fix this problem, simply replace the filter with a new one.

Frozen Evaporator Coil

Another potential problem is a frozen evaporator coil. This can happen if the furnace is not getting enough airflow. To fix this, you will need to thaw out the evaporator coil and make sure there is no ice blocking the airflow to the furnace.

Bad Thermostat

A bad thermostat can also be the culprit. If the thermostat is not working properly, it may prevent the furnace from kicking on. You will need to replace the thermostat with a new one to test this.

Wrong Thermostat Setting

It's possible that your thermostat setting is set too high. If the setting is too high, the furnace will not kick on because it will think the house is already warm enough.

In addition, you could have the thermostat set to off or on cold. If this is the case, the furnace will not kick on.

Defective Gas Valve

A defective gas valve can also prevent a gas furnace from kicking on. If the valve is not working properly, it will not allow gas to flow to the furnace. This is a serious problem, and you will need to call a professional for assistance.

Pilot Light Is Out

If the pilot light is out, the furnace will not be able to ignite the gas. To fix this problem, you will need to relight the pilot light.

Superheated gas passing through holes inside a gas furnace

Bad Ignition Switch

The ignition switch ignites the gas in the furnace. If the switch is not working properly, it will not ignite the gas, and the furnace will not kick on.

Failed Blower Motor

The blower motor is responsible for circulating the air in the furnace. If the motor fails, the furnace will not kick on.

If you hear strange noises or notice a burning smell coming from the furnace, this could signify that the blower motor is failing, and you will need to call a professional for assistance.

Dirty Flame Sensors

Dirty flame sensors can also prevent a gas furnace from kicking on. The sensors are responsible for detecting whether or not there is a flame present. If they are dirty, they may not be able to detect the flame, and the furnace will not kick on.

To clean the flame sensors, simply remove them and scrub them gently with a wire brush.

Closed Gas Valve

The gas valve to the furnace may be closed. If this is the case, the furnace will not be able to get any gas, and it will not kick on.

Check the valve to see if it is in the "open" position. If it is not, simply turn it to the "open" position and see if this fixes the problem.

How Long Does A Gas Furnace Last?

Technician checking the gas furnace for any damages

On average, a gas furnace will last 15-20 years. However, this can vary depending on the make and model of the furnace and how well it is maintained.

If you take good care of your furnace and have it serviced regularly, it could last longer. Have your HVAC specialist service and inspect your gas furnace at least once a year for optimal performance.

Final Thoughts

A dirty and old gas furnace ready for cleaning and maintenance

Almost every gas furnace has a reset button, so if your furnace doesn't seem to be working, it's always good to check and see if resetting it fixes the problem. If you have any other questions or concerns about your gas furnace, reach out to an HVAC specialist for assistance.

Have more questions? Here are other related articles that might help:

Can A Natural Gas Furnace Run On Propane?

How Do I Know If I Have A Natural Gas Furnace? 

How Long Should A Natural Gas Furnace Last? 

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