What Does A Pilot Light Do?

Pilot lights are used as an ignition source for your gas furnace or hot water tank. They create a small gas flame of either natural gas or propane gas.Pilot lights are used in many common household appliances, such as household water heaters, fireplaces and furnaces. Although there are methods to light a burner electronically, gas pilot lights are still used when high energy ignition sources are required. Furnaces typically run off two pilot light sources. In older furnaces, a standing pilot light is used which means that the flame is lit all the time. In modern furnaces, an electronic ignition source is used so the pilot light flame is only lit when your furnace is calling for heat.

The pilot light serves as a method of ignition, and when it is inoperable your furnace or water heater will not function. Checking your pilot light is a simple way to ensure your furnace is running the way it was intended to. We receive a lot of furnace and hot water tank repair calls in Creston and a common cause of the problem is due to a malfunctioning pilot light.


Every pilot assembly contains a thermocouple. Thermocouples are used as a safety feature for both standing pilot lights and electronic ignition pilot lights. The thermocouple works by sensing heat from the pilot burner and when heat is detected, the main gas valve is opened. If there is no heat is present, the thermocouple will shut down the main gas valve to the burners in order to prevent gas from building up. When this occurs, your pilot light needs to be reignited in order for the furnace to produce heat.

How To Re-Ignite Your Furnace Pilot Light

Every furnace is different, but the concept of relighting the pilot light is the same. The first step to reigniting the pilot light is turning off the power to the furnace. After doing so, remove the door covering the internals and set it aside. Look for the pilot valve: a box shaped device with gas lines running into it. Typically, the pilot valve is located near the burners. Make sure the pilot valve is set to the off position. Wait a few minutes to let any remaining gas clear away from the burner area.

Some valves contain a reset button, while others do not. Regardless, the gas valve will need to be turned to the pilot setting.

Using a barbecue lighter, hold the flame over the pilot assembly while pushing down on the reset button. If your furnace does not have a reset button, hold the gas valve knob down for approximately 30 seconds. Finally, slowly release the button/knob.If the pilot light remains lit, you can turn the gas valve to the on position and return power to your furnace. If it does not, the above steps will need to be repeated. If repeated attempts to light the pilot light fail, please call us to arrange for a technician to come to your home.