Water heater install

[bajabug fred]

Good afternoon all i am new to the site and i have been living in my 5th wheel for a few years and i have been doing the repairs as needed. i bought the toy box new in 2005. so far all has been good. Starting to be time to replace or upgrade some of my equipment. I am a mechanic and welding fabricator so i can do just about any repairs needed. I have an old Atwood G10 3E water heater that needs to be replaced. I talked to the new company that services my trailer with factory parts and bought a replacement water heater GC10A-4E SP. In looking at it is is the same but it has 4 wires instead of the 3 wires on the original water heater. I have read many post about his but the one thing that is different is that my old water heater is gas only and i have only one switch mounted in the stove fan with other switches. I do not have a separate switch for the electric side on the new water heater. I would like to use that feature so if i ran out of gas i could use the electric until i got more gas.I am able to run 120 vac to the unit if need be and also wire in another switch if need be. Is there a clear wiring diagram for this conversion? Do i need to interlock the switches? Would it be easier to run a new double switch panel and light and disable the existing switch? If i read the other post correctly both switches are 12 vdc and the 120 vac wires directly to heating element. Any help on this is appreciated and look forward to any replies. Thanks bajabug fred.

[Old-Biscuit]

4E Version uses 12VDC to operate Gas and Electric
Both on/off switches use common 12VDC from fused source
Electric switch sends 12VDC to the Circuit Board via WHITE wire
*Circuit Board sends 12VDC to DC Relay that closes allowing 120VAC to heater element
Need 15A 120VAC Circuit Breaker to supply the AC for element

Gas switch send 12VDC to circuit board via ORANGE wire

BLUE wire comes from circuit board to FAULT Light at switches for visual indication of No Flame lighting/proving it lit and/or if ECO opens/lockout controls

Swap out the Single GAS on/off for Dual Gas/Electric Switches
***Can jumper the 12VDC from gas to electric---but need to run separate 12VDC wire from Electric to the WHITE wire




See pgs 24 & 25 for conversion of 3E to 4E
https://manuals.heartlandowners.org/...e%20Manual.pdf






The DC Relay and element are on backside of water heater tank under the protective cover

[bajabug fred]

Thanks for the info that looks like what i need. I will let you know how it all works out.