It is important to locate the instructions on your furnace to ensure that you know where the different components of the furnace are and how to properly light the pilot light. These instructions are normally found on a sticker somewhere visible but sometimes that information can fade or be damaged. 

The most important part of lighting a pilot light is to not cause a fire, explosion, or any damages. It is critical that the gas valve is turned off so that the gas supply is cut off. This valve van normally be found near the bottom of the furnace with 3 indicators labeled “On,” “Off,” & “Pilot.” At this point the valve should be turned to the “Off” position to cut the gas supply completely. After the valve is shut off, wait for 5 minutes so any unburned gas can dissipate enough so that the concentration of gas is not combustible. If the smell of gas persists beyond 5 minutes, the concentration of gas is still strong enough to cause concern. At this point, it may prove beneficial to introduce a fan to help move airflow into the concentrated gas to help it dissipate.

Once enough time has passed, the valve can be switched over to the “Pilot Light” setting. This will allow enough gas to pass through to ignite the pilot light without releasing the full flow of the “On” position. If you immediately start to smell gas, then there is too much gas being released which could indicate a problem with the gas line. If this is the case, then a professional should be called to come check the furnace immediately.

Once the valve has been switched over to “pilot light,” find and press the button labeled “reset.” This will need to be held while the pilot light is ignited. If you can’t find where the button is located, be sure to check the instructions or look for the make and model online. 

While the “reset” button is being pressed, use a long lighter or match to reach where the pilot light ignites. It may take a couple seconds to ignite the flame so hold it steady until a blue flame appears. Once the flame is lit, you can let go of the “reset” button. 

Once the furnace pilot light is reignited and stable without burning out, you can switch the gas valve back to its “On” position. This should fix the issue and your furnace should be back in working order unless there are other issues that could be prompting the furnace to fail. 

If the pilot light repeatedly turns off on its own, it could be an issue with the thermocouple. The thermocouple is the safety mechanism that prevents gas from leaking when the pilot light is not lit. 

A dirty thermocouple can prevent it from working properly. If there is an excessive amount of dirt, dust, or grime blocking the sensor that reads if the ignition source is lit, then the mechanism may interpret the pilot light as off. If the thermocouple fails to read properly, then it will shut off the gas supply. The thermocouple can usually be cleaned by gently wiping the tip with fine grit sandpaper. 

The thermocouple can also be bent which can shift the sensor away from where it needs to be to sense if the pilot light properly. All that needs to be done is to bend the thermocouple back to where the sensor is close enough to the flame to sense ignition. 

If the thermocouple is still failing after it has been cleaned and positioned properly, it could be a sign that the thermocouple is broken and needs to be replaced. In these instances, a professional should help install a new thermocouple to prevent any further issues. 

A flame that waves or isn’t blue is usually an indicator that there is blockage near the gas supply opening. This is problematic because a poorly lit pilot light can cause the thermocouple to get an inaccurate reading causing the gas supply to be turned off. This can usually be fixed by cleaning up the pilot light gas opening to ensure that gas can be released without obstruction. 

The placement and positioning of a furnace can cause issues as well. If the furnace is somewhere enclosed without a supply of fresh air, the pilot light might extinguish itself from lack of oxygen. On the contrary, the furnace can also be placed somewhere with a draft that continues to blow out the pilot light. In both instances, the furnace should be moved to a more appropriate area to ensure that the pilot light is able to stay lit.