Thermocouple. Th? thermocouple is a safety gadget t?at detects w?ether ?our furnace's pilot light-weight is lit. The thermocouple consists of ? steel rod that is definitely put incredibly shut t? the pilot gentle'? flame. Thermocouple. ?he thermocouple or flame sensor i? a small metallic gadget positioned in the flame route ?file t?e pilot gentle.