[mjlaupp]

Water heater noise:
W1) Are you hearing the gas burner flame rumble and thinking this is a boiling noise? I can hear my gas burner every time it lights.
W2) Are you using the gas water heater and the electric water heater at the same time? You could actually be boiling the water if the pressure is low in the water supply. If the water pressure is ok, try heating the water with only one of the two options and see where the problem is.
W3) The electric element could be cracked and letting water contact the internal 110vac heat wire. Replace the electric element. The fuse may not blow even though the internal wire is exposed to water.
W4) A buildup of scale on the heat element(s) can cause the boiling noise when the water next to the element flashes to steam. Clean (flush) the hot water tank and check and/or replace the anode rod.

Fridge:
F1) The fridge can only cool to some limit below ambient temp. 100 degrees is probably pushing the limits.F2) How level the TrailManor (fridge) is will affect cooling efficency.
F3) A 12v electric auto radiator fan with or without a thermostat and hung on the outside or inside of the outside fridge vents may help fridge cooling when the TrailManor is set up.

AC:
AC1) The 'High/Low Cool' setting should not affect the icing problem. It only changes the fan speed.
AC2) The book says to turn the AC to 'fan only' to de-ice the coil.
AC3) I haven't looked in the book, but I thought the AC unit had a coil icing dector and cutout circuit.

MJL