Dometic Atwood gc10-4e hot water heater overheating

[Cartwrk]

A few months ago we had a new Dometic Atwood gc10-4e 10 gallon gas/electric hot water heater installed. After installation we discovered that the electric wasn't working. The mobile repair guy wouldn't get back to us so we just used the propane for a few months, which worked fine. Yesterday we had some work done at an rv shop and they got the electric working, which we set to be the heating method overnight (propane was turned off so we were using electric only). The next morning the hot water heater was steaming and water coming out of the release valve. The plumbers putty on its water connections was warm and soft enough to come off easily on your finger. Water coming out of the faucet measured 150+ degrees.

I'm trying to understand what has happened here - it seems like when using electric for the first time on this relatively new hot water heater that the thermostat ran too hot or something. I have read online of people having the circuit boards fail with this particular model but I'm not sure that would cause this particular problem.

If I could figure out how, I'd just as soon fix this myself by following instructions or a youtube video, but I don't have a lot of experience in the area and I'm not sure where to start or what to replace. At the moment I'm not even sure if it's safe to just go back to propane only because I don't want to inadvertently make things worse.

Any input is appreciated.

[dougrainer]

Cartwrk wrote:
Okay so I set the hot water heater to propane only and it initially lit and heated up. I thought it was okay but a day later and now it appears it will not stay lit. If I turn off the switch and back on again it lights up and then goes out again and the red light next to the switch comes back on again.

We weren't having any problems with using the propane with the hot water heater until the repair place rewired the electric to get it working, but that may be just coincidence? We have plenty of propane in the tank. When I switch the propane off and back on I can hear it start up but it will not stay lit for some reason.

A few years ago Atwood had a problem with ALL the control boards. So, you need to get to a Atwood service center(most RV service centers are Atwood centers also) and get your Model/Serial number and spec number submitted to Atwood to see if your circuit board was built during that bad period. Odds are the Control/Circuit module is bad. Your problem was one of the problems with the bad serial numbers. I believe your Atwood spec plate should indicate the month/year the WH was built. Doug

[Cartwrk]

Okay so I set the hot water heater to propane only and it initially lit and heated up. I thought it was okay but a day later and now it appears it will not stay lit. If I turn off the switch and back on again it lights up and then goes out again and the red light next to the switch comes back on again.

We weren't having any problems with using the propane with the hot water heater until the repair place rewired the electric to get it working, but that may be just coincidence? We have plenty of propane in the tank. When I switch the propane off and back on I can hear it start up but it will not stay lit for some reason.

[Old-Biscuit]

If they HARD Wire the 120VAC to the element it has NO TEMPERATURE CONTROL
The T-stat/ECO (in outside compartment) are for BOTH gas/electric

W/O wiring it correctly they have BYPASSED the t-stat/eco and the electric will not shut down until T&P BLOWS and 120VAC CB Trips

IDIOTS! have placed you in DANGER ....water heaters are mini boilers. Safety controls are required. They stupidly bypassed those safety features

SEE/READ Pgs 23, 24, 25 to understand the necessary conversion for proper operation and SAFETY

[Cartwrk]

I really appreciate all of the info in this thread and am working to process it. We seem to have had really bad luck getting rv work done in the Boise area for some reason, and I can't afford to just keep putting this much money into this one issue, so I've pretty much reached the point where I feel like I'm going to have to figure this out myself to get it fixed. The hot and cold lines started leaking too as apparently they weren't sealed properly combined with the water overheating I guess. That I can fix though so after I'm done I will switch to propane (hopefully it doesn't overheat) and then work on figuring out and getting the electrical fixed. Thanks again for everyone giving me some info to work through. I'll also keep going through what other online resources I can find.

[Traver8]

I can suggest one other possibility. It happened to me so I know it is real. I had the relay that switches the 120v to the electric element stick "on" thus powering the element 100%. This caused very hot water and release through the relief valve. In this scenario, the thermostats were not involved In the control of the heating so they were not able to provide control.

[dougrainer]

Cartwrk wrote:
This is in a class A motorhome. It's a 2000 Holiday Rambler Endeavor. We bought it used a year and a half ago. The water heater we had replaced used an actual electrical extension cord for the electricity (as we discovered when it started leaking) so I'm pretty sure it wasn't original, and I don't know what model it was. The mobile rv guy used the same cord, rv shop yesterday said it had scorched wires and said they hard-wired the new hot water heater up properly for electrical use. We live in the rv full time so hoping to get this figured out soon. There's an ongoing saga regarding this hot water heater situation that has now involved three separate repair companies/people, including outright fraud/theft the first time, and now five months and a total of $2400 later, no hot water. It's almost funny, but I'd really like to fix it.

Does it seem likely that it's safe to switch back to propane for now or could that cause more problems at this point?

Monaco/HR used what looks like an extension cord to supply 120 power to the Dual Water Heaters. So, that part was normal. As OLD BIS stated, you have had some VERY Incompatant people working on your RV. They just plain did NOT know how to install and wire a 2004 to current Atwood Water Heater.

[BFL13]

Is it really on 120v? You have 50a AC? so maybe they "hard-wired" it for 220? No idea if it would even run that way or just overheat the element--just a thought. (scorched wires on the previous cord too?)

[Flute_Man]

I would switch back to Propane and see if that still works properly. If it is not proper now then maybe the service Company didn’t do it correctly. No harm in switching it over to Propane and I would shut the electric off completely so you know exactly what the gas is doing.

[Cartwrk]

This is in a class A motorhome. It's a 2000 Holiday Rambler Endeavor. We bought it used a year and a half ago. The water heater we had replaced used an actual electrical extension cord for the electricity (as we discovered when it started leaking) so I'm pretty sure it wasn't original, and I don't know what model it was. The mobile rv guy used the same cord, rv shop yesterday said it had scorched wires and said they hard-wired the new hot water heater up properly for electrical use. We live in the rv full time so hoping to get this figured out soon. There's an ongoing saga regarding this hot water heater situation that has now involved three separate repair companies/people, including outright fraud/theft the first time, and now five months and a total of $2400 later, no hot water. It's almost funny, but I'd really like to fix it.

Does it seem likely that it's safe to switch back to propane for now or could that cause more problems at this point?

[Old-Biscuit]

Atwood GC10A-4E is a combo (gas/electric) model that uses the SAME set of T-stats, Common DC for controls and same circuit board

You don't state/show what RV you have....Year/Model etc
If Water heater was an 'upgrade' from an older version then repair shop didn't wire it correctly ....Using DC for both gas/electric on/off switches and DC to relay that when it closes allows 120VAC to element




Normal t-stat is factory pre-set to 140*F...gas and electric
ECO (Energy Cut Off) ---ie: High Temp t-stat is factory pre-set for 180*F
If ECO opens then ALL DC is shut down...no more heating and RED Fault Light is triggered so Owner has a visual indication of problem


Overheating and NO RED Fault Light
Could be because the T-stat is not being held TIGHT against tank wall
Air space can allow for higher temps before t-stat opens


Water coming out of T&P Relief Valve
T&P POPS Open at 210*F/150 psi
'Weeping' can occur due to loss of Air Pocket in top of tank above Hot outlet dip tube
Water SWELLS when heated......air can be compressed to control pressure increases. Water can NOT be compressed so w/o air pocket pressure will increase enough to cause weeping/dripping from T&P