Fix Your Foundation Before It’s Too Late

Clean Or Replace The Thermocouple In Your Gas Furnace If The Pilot Light Won't Stay Lit

by Howard Barnett

If you turn on your furnace just to find that it isn't blowing warm air, take a look inside to see if the pilot light is lit. If it isn't, chances are that your thermocouple isn't working properly. This part acts as a sensor and signals the pilot light to stay lit when you turn up your thermostat. Cleaning the existing thermocouple or replacing it with a new one is easy to do and doesn't require knowledge of furnaces.

Use The Following Materials

  • rubber gloves
  • flashlight
  • pliers
  • emery cloth
  • lint-free cloth

Remove Corrosion From The Thermocouple

Turn off your furnace. Put rubber gloves on and open the access panel. Shine a flashlight into this area if you are having difficulty seeing inside. Next to the pilot light, you will see a long, thin tube that has two wires attached to it. The ends of the wires are connected to the pilot light assembly. The long tube is the thermocouple. Inspect the ends of this part. If they have a white, chalky substance on them, it is corrosion and can be preventing the thermocouple from working.

Rub a piece of emery cloth over the corroded spots. Emery cloth is a flexible material that is similar to sandpaper and easy to work with. Once the corrosion is removed, wipe the surface of the thermocouple off with a lint-free cloth. Turn the furnace on and relight the pilot light. This may fix the problem, but if not, complete the steps below.

Replace The Thermocouple

Gently pull the clips that are attached to pilot light assembly. They are on the end of the wires that are connected to the thermocouple. Loosen and remove the nuts that are attached to the thermocouple with a pair of pliers. Pull the bolts out. Slide the thermocouple through the bracket that is holding it in place. Purchase a replacement thermocouple at a hardware or store or home improvement center.

Once you get back home, slide the new thermocouple through the bracket. Insert the bolts and place a nut on the end of each one. Tighten the bolts with pliers. Reattach the wires by clipping the ends onto the pilot light assembly. Turn the furnace on and relight the pilot light. If you feel warm air blowing through the vents in your home, you have resolved the problem.

Prevent your thermocouple from malfunctioning in the future by wiping it off with a cloth when it appears dirty and removing buildup with an emery cloth. Taking these steps will keep your furnace running without any interruptions or needed heating repair