Rialta Motoraid important tip.

[CGAZ Paul]

I have a 1999 Rialta HD. About 2 years ago I replaced the Atwood marine water heater with an exact replacement. Not easy to install but ended well. I made a discovery as to the use of this which isn't really addressed in the manual.
I live in Arizona where it gets hot. The temp gauge on the dash always stays in the middle and the rig never overheats. HOWEVER! after several hours, the water in the heater is extremely hot. MY MISTAKE: I turned on the water heater switch as soon as I was hooked up at an RV park. To be safe and avoid the thermal overload breaker (nicely hidden inside the water heater wiring cover - and nearly impossible to find) from tripping. USE UP THE EXISTING HOT WATER BEFORE TURNING ON THE SWITCH.
Apparently, the water can get heated beyond the temps that the overload is rated at. This is fine as long as you don't energize (turn on) the water heater. Once it is turned on, the limit switch will sense the heat and trip the little overload breaker. This tiny button is inside that wiring access cover on the side of the water heater. It is buried under the insulation and very tiny. Once you find it, push it in. It should feel like a bit of a "click".
Since I now have my "new procedure" of using the first batch of motor-heated water first; it has been fine. Hopefully this will help anyone from the agony of resetting the button.
Best of luck always!
Paul

[DCHitt]

Yes the engine does make the water very hot. I hope you have a temp mixing valve so you can set the temp at the sink.