If your pilot light on your gas furnace won't stay lit, the thermocouple may need to be cleaned or replaced. This part is a safety device that turns off the gas if the pilot light fails to stay lit. Learn how to clean and replace it with the following steps. 

Use The Following Materials

  • flashlight
  • emery cloth
  • soapy water
  • lint free cloths
  • screwdriver
  • replacement thermocouple

Clean And Test The Thermocouple

Turn off the power to the furnace. Open the access door to locate the thermocouple. A flashlight will make it easier to see this part. It is a long, metal tube that has two wires coming off of it that lead to the pilot light's housing. Use an emery cloth to remove corrosion and dirt from the ends of the thermocouple. An emery cloth is similar to sandpaper, but has fabric attached to one side. This makes it easy to handle the cloth as it is being moved over small surfaces.

Once all visible dirt has been removed, wipe the thermocouple off with a damp cloth to remove any residue that is still on its surface. Dry the thermocouple off with another cloth. Turn the power back on to the furnace and adjust the thermostat. Relight the pilot light and close the access door. If the furnace continues to operate, the problem has been resolved. If not, replace the thermocouple with the following steps. 

Replace The Thermocouple

Turn off the power to the furnace. Open the access door and locate the wires that are coming off of the thermocouple. Gently unclip them from the pilot light's housing. Use a screwdriver to loosen and remove the screws that are holding the long, metal tube in place. Slide the thermocouple through the bracket that surrounds it. Bring the thermocouple with you to a hardware store so that you purchase a replacement thermocouple that is the proper size.

Slide the new thermocouple through the bracket. Insert the screws in each end of it and tighten them with a screwdriver. Clip the wires to the pilot light's housing. Turn on the power to the furnace and adjust the thermostat. Relight the pilot light and close the access door. The pilot light will no longer turn off when you are operating the furnace.

Prevent problems from occurring in the future by inspecting the thermocouple throughout the year and removing visible dirt or corrosion from its surface with an emery cloth. 

To learn more, contact a company like Elite Heating & Air Conditioning. 

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