We own a 2016 Jayco 318RETS with an Atwood water heater model GC6AA-10E.
We switch the water heater to gas, it works fine.
We switch it to electric, both electric and gas come on at the same time. The water is so hot it will scald you.
We’ve checked fuses, cleaned and checked wiring.
Any ideas?
My 2018 Greyhawk was doing the same thing, but the gas would only turn on with electric turned on . Took me approx 4 months to figure it out . Finally figured out that theses two systems share a common ground connection, in my case the gas side had a intermittent (bad ) ground connection. My bad connection was outside in the wires that you can see when you removed the access panel on exterior wall. Try very gently unplugging the control board multi wire plug and check for any moisture or corrosion on the plug, clean it very gently if needed with a toothbrush and electric terminal cleaner. Be very careful when plugging Back in to control board these connections will bend Very easy. Also try turning gas and electric on at same time then turn only gas off and see if electric stays on . If it does you have a bad ground connection. Do this before unplugging control board . My problem was due to hard sideways rain storm (wind =30mph for 2hrs) blowing into access panel. Good Luck maybe this will help you…..( a125b@bellsouth.net)..
Looking at the schematic it appears that the board is in total control of what is happening. To me it appears to be a board problem at this point because both items don't come on at the same time when in gas mode.
You will need to measure the inputs to the board and also make sure the grounds are good. If the inputs are good but the output is incorrect, the board is probably at fault.
A separate 12 volt input tells the board whether to select gas or electric. It should only select both if both remote switches are turned on at the same time. Verify that only one input is present when its switch is activated.
Many of us use both switches at the same time to heat the water up quicker. It is not a problem because the thermostat should shut down the heating when the temp is reached. The temp should be the same, provided the board is OK, whether you are using gas, electric, or both.
When in electric mode the board will energize a relay that connects 120 volts to the heating element. There is no connection to the gas side other than internal to the board.
Are you 100% sure that the electric side is coming on when the switch is selected and not that the gas is just coming on regardless of the switch selected?
I have attached the manual for your water heater.
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Jim
Retired electronic technician (45 years in the field)
2017 Greyhawk 29W (solar & many other mods)
wife (maybe I should have given her top billing)
Linear Mode
