Atwood water heater problem

niksagkram wrote:
Just checked to see if the heater fired up when I shorted out the wires as suggested. Heater started when I shorted out the brown wires, but nothing when I tried the red. Checked red wires with the tester, no power there. Also, I pulled off the wiring harness on the circuit board and checked them with the tester, no power at all. Should there be? (remote switch is ON)

OK chances are the temp sensor on the brown wires is the issue, go buy the kit (about $20) and replace them, I don't think you will see power on those wires, they are all in series, one of those disks I believe are normally open and the other normally closed. The furnace only comes on when both are in the closed state. Here is how I believe it works: The red pair are normally closed and will open up when the water reaches max temp. The brown pair are normally open. They close when the temp drops below a certain amount to bring it on. So if it is stuck open then the furnace will never start. You shorted it out completing the circuit through the red ones and the heater fired on. if you had left it shorted it should have heated the water to operating temp then the red ones would have opened the circuit and shut it off. Leaving the brown ones shorted would have triggered it to restart almost immediately, which normally would not happen until the water had cooled somewhat. The reason for the 2 is because say the red pair stayed shorted, you woudl keep heating. That does not happen because the brown pair in series is sitting in an open state, until the temperature drops to a certain level. You woudl have to have both disks in a closed state to get an overheating failure. pretty unlikely. That is also why you should always replace both even if one is still OK.