Dometic water heater. WH-6GEA............

[Kevin J]

Water heater works fine on propane but when electric turned on it trips the circuit breaker after a few minutes.

I have filed a ticket with Dometic but any views welcome.

Thanks in advance.

[Kevin J]

further diagnosis...........

- from cold it seems to heat the water. (Volts reads 115v across heating element terminals).
- disconnected the heater element wires and tested for continuity; shows 11ohms.
- seems like DC power into circuit board (top wire) and out of bottom two wires.
- tested the thermostats which also seemed to show continuity when wires disconnected.

My initial assessment is it may be a thermostat problem? Maybe therm does not shut off and trips circuit breaker instead.

But works under propane ok. Is this because the ECO shuts it off on propane side before breaker trips?

Water does seem hot (steamy).

[Kevin J]

Just found this...........

"You can pull the wires off and test the thermostat with a continuity tester if you're too cheap to buy the replacement kit. When the water is cold, there should be continuity between the contacts. When the water is hot, there shouldn't be."

Not sure I tested T'Stat continuity with the water hot. It might have failed closed which is why i get continuity.

[JRTJH]

Originally Posted by Kevin J

Just found this...........

"You can pull the wires off and test the thermostat with a continuity tester if you're too cheap to buy the replacement kit. When the water is cold, there should be continuity between the contacts. When the water is hot, there shouldn't be."

Not sure I tested T'Stat continuity with the water hot. It might have failed closed which is why i get continuity.

That is "normal operation" for the thermostat. If it doesn't "close the contacts" it couldn't provide power to the electrical heating element. So, that should not be tripping your circuit breaker since it has to open/close in normal operation without tripping the breaker....

I'd suspect, if the electrical element is not shorted to ground, you have a wire that's "pinched and the insulation finally wore off the wire" and is shorting out the electrical side of the water heater. We have had several (3 or 4) members who have found a crimped wire "folded under the thermostat mounting area" that was the cause of their "breaker tripping problem"....

But, the thermostat opening/closing or remaining closed would not trip the breaker in normal operation, the only "condition" that you'd have is once the water got too hot, the "high limit switch" would open and you'd have to reset the button under the rubber cover before it would work again.... That event doesn't "trip the breaker either"....

[jxnbbl]

Just like a house electric water heater...depending on the water quality/age those heating elements deteriorate...sometimes quickly. Even when it has continuity they can short out.

[Kevin J]

Thank you both.....

"I'd suspect, if the electrical element is not shorted to ground."

Funnily enough the dealership just got back to me with a similar message that it is most likely a short to ground.
Of course this is the one test I didn't do. ;o)

Thanks again and I'll post the result.