Furnace Pilot Light Thermocouple

Standing pilot lights are common in older furnaces but many newer furnaces have intermittent pilot lights or hot surface igniters.

Furnace pilot light thermocouple.

If the pilot light goes out the thermocouple will lose its voltage and the gas line to your furnace will be closed. If you re having trouble locating the pilot or thermocouple double check to make sure your unit actually has a standing pilot light. A thermocouple is a safety device that helps control the gas supply in gas heated furnaces. This rod is connected to your furnace s gas valve.

In furnaces and water heaters and in some ranges and dryers the pilot light is accompanied by a safety device called a thermocouple a heat sensor that turns the gas off if the pilot flame is extinguished. This is all done as a safety feature so there are no gas leaks. The thermocouple is a gas furnace component located near the pilot light burner. Newer gas appliances have igniters that start the pilot light as needed.

This maintains gas flow to the pilot until the thermocouple gets hot enough to open the main gas valve. For a basic test attempt to turn on the pilot light again. The function of the thermocouple in your gas furnace is to check to see if the pilot light is on or off. A thermocouple is a safety device that s used to detect whether or not your furnace s pilot light is lit.

The thermocouple detects the pilot light as it can sense the heat the pilot light creates. Light the standing pilot. If the pilot light won t stay lit the thermocouple may be faulty and should be adjusted or replaced. If your furnace pilot light won t stay lit then it might be an easy fix.

When it stops working the furnace s pilot light also turns off. In these systems the pilot will only light in the case of hot surface igniters the igniter surface heats when the thermostat makes a command for heat. When your pilot light is lit the heat from the flame sends a voltage through the thermocouple that keeps the gas line open. Place the lit match or ignited lighter tip at the pilot while depressing and holding the reset button or depressing the knob as appropriate.

In this episode of repair and replace vance shows how to replace the thermocouple. Depress the button or knob for about 30 seconds. It contains a metal rod that is placed very close to your pilot light s flame.