Seeking Water Heater diagnostic help ...

[Papabear7]

I have a 2016 Passport with an Atwood GC6AA-10E water heater, the WH is 2 yrs old, dated 3Q2015. I've read a lot of threads about various issues, but I'm still lost on trying to figure out what has made ours stop working.

Here's what happened; we were on a trip at North Rim GC two weeks ago, using propane multiple times to heat water in the am. I ran it one morning, and while running hot water in the shower, ran out of pressure--we had tanked up fresh water a day before, and I really didn't expect to run out that fast, but we did--ran fresh out. The water pump works fine, I shut if off quickly. We had plenty of 12V power, we just ran out of water. At first, I freaked, thinking we emptied the 6 gal WH tank, but then realized the issue with burning up an element with a dry tank is when on electric WH ... we were not, strictly propane. Then I also read where the WH tank would not have emptied by just running low on the fresh tank, so ...

I've now tried heating with the electric side while plugged into house power. The electric WH rocker switch lights up when on, but I get no 'indicator light' at the circuit board and no hot water after a while-long test. Also, when we switch on gas WH switch, red rocker lights up again, but no ignition & no fire in burner tube. Burner tube looks clear. I've taken off the fusible link at the thermostat and wired straight without it in-line, and it makes no difference. With the Atwood, there's apparently no resets to push, and I have switched the house-power breaker in the trailer off and back on--still no electric WH.

My first guess is somehow the ECO or P+T thermostat inserts (the ones with two poles each for the red & brown wires) have either burned up or coincidentally quit working with this low-water incident. I'm about to just replace those, but would like some input as to whether there's more I can check or if I'm on the right track. All the wiring connections look clean, solid. I can't get any kind of indicator light on the board at the heater to light up or flicker ... just puzzled. Is the running out of water an influence to shutting down the WH? Any help is much appreciated ... I'd like to avoid a tow to the dealer an hour away and many bucks at risk. Thanks for reading.

[chuckster57]

If you ran out of water with the WH trying to heat water, then yes its possible you "cooked" the thermostats. They are cheap enough to replace. I would think they should have continuity across them if checked with an ohm meter.

[Papabear7]

I did try to measure resistance across those poles while I was messing with the removal of the thermal link, but I think my multimeter is either junk or I didn't get a good handle on the connections. Thanks for the pointer, I will focus on the thermostats first ... I suppose if they are cooked, that would also eliminate the light from coming on the circuit board.

[Papabear7]

After checking continuity across thermostats, next went to the board, using the Atwood manual for checking continuity at various pins.

Then, researched Dinosaur and came up with the UIB-64 being the right replacement. Talked to their tech, and he walked me through meter checks to make sure power was coming to the board before we decided it was the board only.

Highly recommend Dinosaur for any troubleshooting related to possible board failures. The tech wanted to make sure my problem would be solved rather than rely solely on continuity checks on the old board.

Anyway, new board, 3-year warranty, and water heater is back to normal. Love it. Fixed for $115, no trip to the RV shop. Thanks to other posts I found here to learn about this.