Ao smith water heater thermocouple – A worn thermocouples can prevent the pilot light from staying on, in which case you may need to replace it with a new one. Turn off the flow of gas to the water heater by placing the shutoff valve on the gas line running to the water heater. Turn the handle on the shutoff valve so that it is perpendicular to the gas pipeline.
Look for the telltale access panel, which is at the bottom front of AO Smith water heater. Remove the mounting nuts with a nut driver and set the panel out of the way. Identifying the Ao smith water heater thermocouple, which is a unit having one end connected to the signal lamp and the other end connected to the gas line that feeds the pilot flame.
Unscrew the fittings on both ends of the Ao smith water heater thermocouple using a wrench. Turn fittings counterclockwise to remove them and remove the thermocouple. Wood fit on the larger end of the new thermocouple on the gas line where you removed the old one. Thread the other end of the indicator unit. Tighten both fixtures with a wrench. Reset gas supply and replace the cover when you have lit the lamp.