Gas Furnace Pilot Light Thermocouple

A furnace thermocouple is a device on a standing pilot gas furnace that s responsible for opening and closing the main gas line to your home s heating system.

Gas furnace pilot light thermocouple.

If it determines that the pilot light is off it shuts down the flow of gas. A thermocouple is a safety device that s used to detect whether or not your furnace s pilot light is lit. While holding the pilot light button down i get a blue flame with a yellow tip that s over an inch in length. The thermocouple which operates as a safety device turns the gas supply off when the pilot light goes out.

When the sensor is not heated by the pilot flame the solenoid closes the gas supply line. It contains a metal rod that is placed very close to your pilot light s flame. A slim rod shaped flame sensor sits in the path of your pilot flame where it collects and then transfers heat down via a flexible connector wire or tube to signal through an electrical charge that the main gas valve should open. It consists of a heat sensor connected to a solenoid.

If the pilot light won t stay lit the thermocouple may be faulty and should be adjusted or replaced. While this is an excellent safety feature a faulty thermocouple may decide arbitrarily that your pilot light is off when you want it on shutting down your pilot light and your furnace. When a thermocouple fails the pilot light won t stay lighted. When your pilot light is lit the heat from the flame sends a voltage through the thermocouple that.

Our photo left shows how you may spot the copper tubing of the thermocouple extending between its sensor at the pilot flame of a gas burning furnace and its connection to the gas control valve. It is a safety device that shuts off the gas if the pilot light goes out or the electric igniter fails. The thermocouple is a gas furnace component located near the pilot light burner. This rod is connected to your furnace s gas valve.

The thermocouple is below the pilot light but the flame is definitely touching it. A gas furnace thermocouple is in place to shut off the gas line when the pilot goes out or the flow of gas is interrupted on the way to the pilot it works as a type of sensor and if it fails your furnace will not light a thermocouple is the right hand man of the pilot light as it reads the pilots temperature on a rating which tells it to keep the gas flowing. I ve held the button down for over the recommended 60 seconds. Thermocouples detect pilot lights by sensing the heat they produce.

Typically the thermocouple sensor is mounted right in the flame of the pilot light on gas fired heating equipment.