2021 Montana 3813MS Suburban water heater SW12DEL

[Got2Camp]

We have an issue with the breaker tripping on our electric water heater. SW12DEL We replaced the element, same problem. It trips as soon as you turn the switch back on. It works great on propane.
Checked the anode rod, looks good, same issue. Checked the wiring and everything is connected correctly. The outside switch seems to be fine. Tried to reset several times. Nothing has worked. Just running off of propane for now. Any other ideas to try? We can't get to the water heater without cutting open an inside cabinet so left that until we knew what we should be looking for. Thank you for any ideas.

[chuckster57]

The switch on the outside lower corner is known to fail. Also the wire from the switch up to the thermostat is also a known issue.

[sourdough]

Do you have a VOM and know how to use it? The 120vac circuit to the hwh is not complex but has several "stop off" points that might be your issue. To kick the breaker as soon as you turn it on there is something shorted. First thing I would do is turn off the switch on the water heater (mounted upside down) then turn on the breaker. That will eliminate the water heater. If it trips your problem is back toward your power center and there is a relay on the back side of the water heater known to cause issues. If it does not trip then the issue is beyond the switch on the heater or beyond. The circuit runs through the hi limit switch and the element - you've replaced the element but at any of those connections if there is a loose or crooked wire touching something it will trip the breaker.

[ChuckS]

I would be going directly to the remote relay that is wired inside a junction box on the top corner ( backside of the WH)

You will most likely find that relay is melted and shorted out. The relay is 12 vdc powered and switches the 120 VAC going to the WH electric side..

Edited to add: you have an Inside switch for both electric mode and LP mode.. the inside switch for electric mode IS Wired to the remote relay circuit to switch 120 vac to element and thermostat on and off

[ChuckS]

Images of remote relay for your SW12DEL WH