Thermocouples
A thermocouple is commonly used in standing pilot gas furnaces and water heaters to keep the pilot flame lit.
A thermocouple is technically referred to as a Copple Element and produces millivolts when heat is applied to the tip.
This millivoltage is necessary to keep the pilot valve inside the gas valve open.
If the pilot flame goes out, the thermocouple stops generating millivolts.
Without the millivolts, the valve closes thus preventing gas from escaping when there is no flame.
Thermocouples fail because of oxidation.
It is recommended that you keep the pilot lit throughout the year to prevent excess oxidation.
The thermocouple can be found in many different types of gas furnaces, boilers, gas logs, and gas water heaters.
