Water Heater Switch Malfunction

[sourdough]

Originally Posted by Brentw

Making some guesses and assumptions. At some point near the hwt, the house wire connects to the hwt factory wire ( you already guessed this) . That wire is in my opinion, barely adequate, but will do the job as long as there are no issues. That phoney little switch, while rated for the load, breaks down and causes a high resistance in that line, thus the melted wires. I do not believe the duty cycle on that switch supports very many cycles of switching under load.
I have been considering some changes to that circuit and eliminating that little rocker switch.
Good luck in your repairs.

Thanks and I agree. Never understood Suburban putting that switch there...how many time DO you need to decide you want to turn on that element? Then the switch is extremely light weight - just don't see it handling 15A on/off continuously. Best I can figure the switch caused the problem; overheated and melted; on the way out it generated enough heat to melt the wires feeding it....then? Somewhere upline it caused an open; no thrown breaker, no power to switch etc. That's why I've taped the breaker open to prevent it being placed in service - there is an open ended 120vac wire sitting in there somewhere. Even though I've placed some heavy duty fire extinguishers in the trailer, I don't want to find the problem in that fashion.

[ChuckS]

Since you do have an inside switch then there IS a remote relay for the electric heater element

It’s usually jammed on the backside of the water heater up toward the front... that relay is controlled via 12 VDC and gets 120 VAC from the junction box to power the electric heating element

Item circled in yellow is a remote relay for suburban SW12 series furnace with a separate inside switch for electric mode operation

[ChuckS]

Another pic t9 perhaps help you out

[ChuckS]

Wiring diagram showing two inside switches .. one propane mode and other 120 elect mode.. remote relay circled in red at diagram

See attachment

[sourdough]

Thanks Chuck. I figure that junction/relay box is what I'm wanting. From what I can tell it will be the location for the transition from the Romex to individual wiring. It also appears to be attached to the vicinity of the body of the hwh as I figured looking at the wiring. Since I can get by with LP, although I don't want to, I'm going to let warranty pull the tank....I'm working on Thanksgiving!! Thanks again.

[ChuckS]

Glad it’s under warranty.. on my unit I’m fortunate to have a false panel on one of my lower kitchen cabinets .. I can get to the water heater control module and check valve on outlet side of tank.. otherwise it’s a pain accessing thru the basement

[sourdough]

Yes, the back of the wh is flat dab in the middle of the abyss under the flooring in the middle of all the wiring/plumbing etc. Only access will be by the removal of the wh. Not a big thing but when staying in it the process becomes more problematic.