Mar 03, 2017
Depending on the model, some gas furnaces, water heaters, and broilers ignite by an electrical spark method. In most cases, a gas pilot light is necessary for firing. Occasionally, a unit will not operate properly because the pilot light is out. In that case, it may be necessary to replace athermocouple. A thermocouple is the copper tube with a bulb-like end that is raises in temperature because of the pilot light.
It is best to begin by attempting to relight the pilot light following the instructions attached to the furnace, water heater, or broiler unit. Usually, a gas cock with three settings will be evident. Simply turn it to “off,” wait for the gas to clear, and then turn the gas cock to the setting marked “pilot.” Then, hold a match to the pilot while pressing a reset button. If the pilot stays lit, turn the gas cock to “on.” However, if the pilot light will not stay lit, the next step is to replace a thermocouple.
To replace a thermocouple, the gas inlet valve should first be shut off. Then, the access cover should be removed so that the burners are both easy to see and easy to work with. Disconnect the thermocouple from the control unit. This can usually be done by unscrewing a hold-down nut. The other end of the thermocouple may just pull out or there be a second hold-down nut that will need to be unscrewed.