Hot water heater

The water heater has two heat sources, propane and ac electric. The wall switch is for propane water heating. The outside one is for the ac electric element. They are completely independent systems. If you want you can just leave the outside switch on and use the dedicated water heater circuit breaker in the panel to turn the ac element on and off.  What you don't want to do is leave the ac element on with the water heater drained (say for winterization). 

Real quick and dirty:  

1. The water heater has two independent heating systems.  The gas system is operated with a switch inside the coach located on the front of the galley and in newer models in the shower.  The switch(s) only operates the gas system.  

2,  The electric heating element is controlled by a rocker switch on the water heater and by a AC circuit breaker in your FMCO electric panel (sometime labeled, sometimes not).  The rocker switch is located outside the trailer on the lower left hand quadrant of the water heater behind the access door.  

The older manual, at least from 2009, does not discuss the operation of the gas vs. electric water heater operation.  In the Surbuban manual, on page 8, are the instructions for the gas and electric switches.  There is no diagram showing the location of the electric switch nor is there any mention of there being any other possible switches, such as the circuit breaker. There is a note that one can damage the heating element by running it with the tank empty.

For people who are very mechanical, such as many members of this board, the operation of the water heater is simple.  One familiarizes him/herself with the circuits and switches and realizes that the two electric switches (the rocker switch on the outside and the circuit breaker in the FMCO panel) control the electric system and that the gas operation is entirely separate and everything works fine.  For those who are less mechanically inclined and those who have been misinformed by dealers or others, the situation is more problematic.  Many people do not realize that the gas and electric systems operate independently and that the obvious switches only control the gas part of the system.  This is a completely avoidable problem if the breakers are adequately labeled and the user manual adequately describes the operation of the water heater gas and electric heating systems.  Sadly for many, the descriptions are missing or are inadequate, and they end up inadvertently burning up their electric heating element.

BTW, I hold a few patents (or actually my former employers do) and in the process got to know how good patent attorneys think. Now THERE are some really schizophrenic souls (any patent attorneys who happen to read this excluded of course).