Atwood water heater morse code

[Soaringeagle]

In my 2013 Journey 42e I have a 10 gallon Atwood water heater that makes a clicking sound when it is heating in electric mode. When I have changed the thermostat, the clicking stops for a few weeks but eventually comes back. This has occurred with both the standard and adjustable thermostats.
The clicking seems to be coming from the rear of the water heater so I changed the relay, and once again the clicking stopped but came back in about two weeks. The clicking is not constant but very sporadic. I have also noticed that the pressure relief valve has been letting out water periodically while this has been going on. The water heater operates fine in the propane mode.
I am wondering if I possibly have a faulty circuit board or if I have a problem with the quality of power, inverter?, going to the heater.
I have spoken to Winnebago and Atwood, and neither had heard of this problem before.
Any thoughts would be appreciated
Thanks
Brent

[John Hilley]

It's not uncommon for electric heating elements to make a clicking noise as they heat up. It may also be the pressure relief valve. Another poster has a problem with the pressure relief valve, but only on electric.

[Soaringeagle]

I originally thought that it must be the element, but when it goes away when I replace a thermostat or relay, I'm not so sure. I remember the post about the pressure relief valve, and if memory serves, someone had said that their circuit board was to blame. Circuit boards are a bit pricey so I'm hesitant to replace it without a bit more evidence.
Thanks for the input.
Brent

[John Hilley]

Maybe it is a shroud or something that gets moved, tightened or loosened when working on the water heater and then goes back to the way it was eventually. I would look at something metal that expands or contracts. When on propane it may see more heat than when on the electric element and expand differently.

[penman39]

I just had mine pulled out part way because the electric wasn't working.  Those two little devices on the back are temperature switches, not relays. If you relief is popping it sounds like the electric element is boiling the water. Those switches need to make good contact with the back of the tank or they will allow the watertank to get too hot. The bracket that holds those switches in place needs adjusted to allow the base of the switches to make good contact on the back of the tank. Some thermal grease found at Radio Shack will improve the heat transfer to the switches.

This thread shows the two switches on the backside of my heater:
http://www.rvforum.net/SMF_forum/index.php/topic,104397.0.html

[Soaringeagle]

I don't have those switches on my water heater, but thanks for the response.
Brent