Joerg wrote:

Paul Hovnanian P.E. wrote:
Joerg wrote:
Al wrote:
In article ,
"Paul Hovnanian P.E." wrote:

Al wrote:
Any ideas as to why my son's electric hot water heater electrode burned
open? It was cathastrophic! The electrode was replaced and all is OK.

Al

[Image]
The way that the entire element is curved makes me think that it was
severely overheated (probably run dry) at some time.

If the insulation were to fail at one point on an otherwise intact
element, the damage would probably be localized to that one spot.
I think you're right. As far as I know, it was the only one to fail in
that condo complex so early, but still after the warranty expired. Grrr!

There should have been a thermo-switch preventing overheating. Should
have ... maybe pick a better brand next time you need one. Heck, even
our little hot water dispenser has that secondary protection. Ok, that
one is non-resettable but still $1.50 for a thermo-fuse sure beats $150
for a heater.

Problem: The overtemp thermo switches are mounted on the tank near the
element. They will react to an overtemp condition with a full tank
properly. But the element hanging in air will need to reach a very high
temperature in order to conduct enough heat along its length to the tank
in order to trip the safety switch.


On ours it was mounted right at the root of the element. That location
would get hot really fast if there wasn't any water.

That's a better design than ours. So how did we come to be the sole
remaining superpower in the world with such crappy engineering?

--
Paul Hovnanian
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professor; n, One who talks in someone else's sleep.