A Furnace Thermocouple is a device that is used to help control the flow of gas in a gas-powered furnace. The thermocouple is located near the gas valve in the furnace. Furnace thermocouple parts sense the pilot light's temperature as soon as the furnace is turned on. To prevent a gas leak, the thermocouple will shut down gas flow if the pilot light goes out. If the thermocouple for f... https://www.partshnc.com/furnace-parts/thermocouple