Hot water heater power relay

[mbulriss]

A friend with a 1986 PT40 called with a weird power problem to his hot water
heater. He says the 110V power is routed through a relay in the 110 power line
before the normal on/off switch. It appears the relay is one of those 12V
switched relays which controls the 110 power. He has not been able to trace it
to see where the 12V leads go to. The relay appears to be stuck open now and he
gets no power to the hot water heater. If he by-passes the relay, and turns the
on/off switch on, he gets power and hot water.

I do not remember having that set up on my 83, nor on my 91. Does anyone have a
power setup like that for their hot water heater power? What is controlling the
12V power source? An over temperature switch/sensor somewhere? Or is this some
prior owner's undocumented "upgrade"? He is concerned about just bypassing the
relay without knowing what it is for.

Thanks for any ideas.

Mike Bulriss
1991 WB40 "Texas Minivan" (with hot water)
San Antonio, TX (balmy triple digits are us)