Steve B. wrote:
On Sat, 18 Dec 2004 13:46:50 -0500, Jeff Wisnia
wrote:


I won't disagree that the elements could *also* be bad, but "how the F"
will that trip a thermal breaker?



Some bottom thermostat setups only switch one side of the 220 going to
the element. If the element suffers a failure that allows current
leakage but isnt catastropic to the element you have a 110v potential
on one side and a nice ground path through the defect/water on the
other so the element can continue to heat at 110v with thermostat off.
Eventually it could get hot enough to pop the overheat on the top
thermostat

It would seem that the odds of this happening would be somewhere
around the odds of winning powerball but it is possible.

Steve B.


You know, I thought of that, which is why I said "arcane", but I've
never heard tell of that kind of failure before. And you are correct
about the possibility that a single pole lower thermostat could let that
sort of fault keep heating the water regardless of the state of that
thermostat.

But I'm not up to visualizing what kind of mechanical/corrosion failure
would permit that sort of current flow; I'm kinda out of my element
here. G

The OP's problem *might* not be with the control thermostat, but it's
darned well the way to bet.

Happy Holidays,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"