Replacing Atwood WH with Dometic

[jdpm]

My Atwood Gch6a-10E water heater is no longer functional and I'm replacing it with a new Dometic WH-6GEA model. Has anyone else done so?
I'm all ready for the install but now I'm a little unsure of the 12v wiring. The 12V wiring harness in the Winnebago is 3 yellow wires and one white and I have already discarded the old Atwood water heater! I can see the new Dometic has four colored raw wires just like the Atwood but not harness. So I don't know the order of the wires in the 4 wire flat harness. Any suggestions? Thanks.

[Old-Biscuit]

WHY is the Atwood non-functional???


Atwood GCH6A-10E dimensions
16" W X 12.5" H X 18.5" D

Dometic WH-6GEA dimensions
12.62"W X 12.62"H X 20"D

So did you get the 'conversion kit'?
Spacers and wider door panel (Dometic 94016)

Also you are doing away with the 'Heat Exchanger' ---engine coolant lines Capped off??

**Nice feature of the New Dometic is the Element has been moved to front vs backside of WH Tank
Weak link is the Thermal Fuse (blows if 190*F temp is sensed)
Thermal Fuse is sandwiched just above Combustion Chamber and Just below Exhaust Shield....they have reported failures


The Atwood OEM wiring on backside of WH Tank would have been
White---12VDC POS from on/off switch to Circuit Board for Electric
Orange...12VDC POS from on/off switch to Circuit Board for GAS
Blue-----12VDC POS from Circuit Board to on/off switch FAULT Light
Green....Ground/12VDC Neg

The Winnebago wiring uses 3 Yellow and 1 White
3 Yellow would be the 12VDC POS used for Electric/Gas/Fault Light
1 White would be Ground/12VDC Neg

You will need to find which Yellow is for the Electric Switch
Which Yellow is for the Gas Switch
Which Yellow is for the Fault Light

Pg 10 & 11 have wiring of switch information
https://epi.dometic.com/externalasse...4379_81175.pdf


Wiring Diagram for the Atwood AND Dometic...use the same wiring

[jdpm]

The original Atwood with motoraid had a cracked tank and cracked at the threads of the prv. I bought the coach knowing this and didn't want to risk repairing or replacing the tank on an already 7+ year old water heater. Of course, the original is no longer available.
Yes, I have taken care of the engine coolant lines as I was not able to find another unit with the heat exchanger.
I did get the door conversion kit so it should install pretty easily and neatly with that kit. It just won't match my full body paint but I will worry about that when I'm all finished.
I really appreciate you posting this for me. I thought I'd be able to figure it out trial and error but also did not want to risk shorting something in the process. This will be a big help. Thanks!

[Old-Biscuit]

Atwood aluminum tank cracks can be welded

My 2007 Atwood GC10A-4E is still working like new.
Drain/Flush and clean connections routinely

[jdpm]

Originally Posted by Old-Biscuit

Atwood aluminum tank cracks can be welded

My 2007 Atwood GC10A-4E is still working like new.
Drain/Flush and clean connections routinely

I know but did not want to do so not knowing the condition of the rest of the components. Its gone now.

[jdpm]

We got the new Dometic water heater installed today. It's plumbed, wired for 110 and the new door is installed. It's all ready to go except the 4 12v wires. I'm assuming the existing switches installed by Winnie will work with the new Dometic water heater. All I have is a 110 rocker switch and a gas rocker switch. As mentioned earlier, the Winnie wiring harness has 3 yellow wires and one white wire and the Dometic 12V wiring is white, red, blue and green. So now I just have to figure out what color goes to what and hopefully it will work. The mystery is how to determine what each of the 3 yellow wires go to. Is there a way to test it? I don't won't to just start connecting wires and ruin some of the electronics on a brand new water heater. Thanks.

[Old-Biscuit]

Both switches are 12vdc
12vdc is used for electric and gas operation as per the wiring diagram posted

Using a volt meter.
Black test probe on the White wire (should be 12VDC NEG/Ground
Red test probe on any Yellow wire
Turn Gas switch ON....got 12VDC ?
then that Yellow should be connected the the Orange wire on WH
No ...turn gas switch off/turn electric switch ON---got 12VDC?
then that Yellow should be connected to the White wire on WH
NO then that Yellow is most likely for the FAULT light and should be connected to the Blue wire on WH

[jdpm]

Originally Posted by Old-Biscuit

Both switches are 12vdc
12vdc is used for electric and gas operation as per the wiring diagram posted

Using a volt meter.
Black test probe on the White wire (should be 12VDC NEG/Ground
Red test probe on any Yellow wire
Turn Gas switch ON....got 12VDC ?
then that Yellow should be connected the the Orange wire on WH
No ...turn gas switch off/turn electric switch ON---got 12VDC?
then that Yellow should be connected to the White wire on WH
NO then that Yellow is most likely for the FAULT light and should be connected to the Blue wire on WH

Thanks very much buddy! I think we were getting there but its been a hot one today in the direct sun and it started getting dark. I really appreciate your input. It's very helpful. I will post the outcome. Thanks.

[jdpm]

I just thought of something. THe coach is currently connected to shore power. I have a Progressive EMS so I can see the amp draw. If I turn on the 110 water heater the switch illuminates, however, the Progressive shows no draw. I checked the circuit breaker and it is not tripped. This new Dometic w/h does not have the 12v box attached on the bottom at the back with a relay like the Atwood. Do the 12v wires in question have to be properly connected in order for it to function at all regardless of the 110 side being connected? Thanks.

[Old-Biscuit]

YES....wiring diagram and manual

There is a DC Relay in order to trigger the 120VAC to element

Dometic YELLOW wire from circuit board goes to the DC Relay.
120VAC Black (hot) goes to/thru the Relay then to element
W/O DC & DC Relay closing no 120VAC to element

Need to finish the DC wiring from switches to the circuit board
Grounds also

*I would imagine the DC Relay is under the element cover in outside compartment seeing as how Dometic moved everything from backside to front

[jdpm]

Originally Posted by Old-Biscuit

YES....wiring diagram and manual

There is a DC Relay in order to trigger the 120VAC to element

Dometic YELLOW wire from circuit board goes to the DC Relay.
120VAC Black (hot) goes to/thru the Relay then to element
W/O DC & DC Relay closing no 120VAC to element

Need to finish the DC wiring from switches to the circuit board
Grounds also

*I would imagine the DC Relay is under the element cover in outside compartment seeing as how Dometic moved everything from backside to front

Old-Biscuit, the water heater install is complete and fully operational. THANKS VERY MUCH FOR YOUR HELP!
I'm fairly mechanically inclined but can be a bit intimidated by wiring. Especially when it involves a brand new item that I hope not to damage.
So thank you again for your willingness to offer help and all your expertise.

[Old-Biscuit]

Thanks for the update and resolution......Nice Job on the changeout