I have a 2022 Forrest River Surveyor. It has the “dreaded” Dometic WH-6GEA water heater in it. It’s my understanding that this water heater is supposed to run on gas alone, electric alone or on both at the same time. Mine only works on gas alone or gas/electric together. Will not run on electric alone. It has the 4+6 pin connector. Bought the camper New so no one else but camping world has had their hands on it. I’m a Master Plumber with my own business, so I know my way around trouble shooting. I have 12v on the white wire coming from the switch for the electric. When the 6 pin plug is unplugged I have 12v to the pin for the yellow wire. Plug that plug back in and voltage goes away. If I turn the gas switch on my voltage comes back and will run gas and electric. Gas works fine by itself. I’ve had the thermal diode go bad and a circuit board. I’ve tried 3 other circuit boards and get the same results on all 3. Can not figure out why this water heater will not work on electric alone?

Basically the electric switch had the load wire hooked to the ground terminal and the other 2 terminals both had 12v feeds on them. Causing a loop while under load and that’s why my voltage disappeared. Crazy

Sounds like you have high resistance on the 12V wire and meters draw almost no amps and will incorrectly indicate voltage when none exists with a load. Measure the 12V on the yellow wire with a load, sometimes a 12V auto test light is enough.It sounds like you are describing a bad switch?

Not sure if it was clear or not. Electric works as long as gas switch is on. Turn electric switch off with gas switch still on and the electric shuts off. Turn gas switch off with electric switch still on and electric stops working. Unplug the 6 pin plug and check for voltage and the white wire has 12.5 volts, plugged the six pin plug back in and that voltage goes away.

Spindle wrote:Unplug the 6 pin plug and check for voltage and the white wire has 12.5 volts, plugged the six pin plug back in and that voltage goes away.That's the classic example of a high resistance (an open for practical use) connection.

The electrical switch supplies power (no ope circuit). The gas switch supplies power ( no open circuit) everything has power till the 6 pin connector is plugged in. It is actually more of a sign of a ground fault through the board but can’t find where it’s going. I’ve tried 3 different boards and all have the same issues. All the wires, let me say that again, all the wires have the power they are supposed to have with the 6 pin unplugged

Dometic WH-6GEA does not work on electric alone

Roger10378
Explorer II
Aug 07, 2023
I am not familiar with that particular model but most of them work basically the same.

Electric heating is 115 Volt AC but you don't even mention checking for it. 12 volt is for control of the gas so if gas only is working you know the 12 volt is good.

You either have tripped the breaker for the 115 volt or there may be a switch on the unit. Or the electric might have been on with no water and burned out the element.
Spindle
Explorer II
Aug 07, 2023
The electrical switch supplies power (no ope circuit). The gas switch supplies power ( no open circuit) everything has power till the 6 pin connector is plugged in. It is actually more of a sign of a ground fault through the board but can’t find where it’s going. I’ve tried 3 different boards and all have the same issues. All the wires, let me say that again, all the wires have the power they are supposed to have with the 6 pin unplugged
CA_Traveler
Explorer III
Aug 07, 2023
Spindle wrote:
Unplug the 6 pin plug and check for voltage and the white wire has 12.5 volts, plugged the six pin plug back in and that voltage goes away.
That's the classic example of a high resistance (an open for practical use) connection.
Spindle
Explorer II
Aug 07, 2023
Not sure if it was clear or not. Electric works as long as gas switch is on. Turn electric switch off with gas switch still on and the electric shuts off. Turn gas switch off with electric switch still on and electric stops working. Unplug the 6 pin plug and check for voltage and the white wire has 12.5 volts, plugged the six pin plug back in and that voltage goes away.
CA_Traveler
Explorer III
Aug 06, 2023
Sounds like you have high resistance on the 12V wire and meters draw almost no amps and will incorrectly indicate voltage when none exists with a load. Measure the 12V on the yellow wire with a load, sometimes a 12V auto test light is enough.

It sounds like you are describing a bad switch?

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Dometic WH-6GEA does not work on electric alone

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