On Fri, 17 Dec 2004 22:35:06 -0600, wrote:

On Thu, 16 Dec 2004 10:19:12 -0500, Jeff Wisnia
wrote:

The "most likely" cause of it tripping is that either the upper or lower
thermostat got "sticky" and didn't open, and the temperature in the
heater rose to the point where the thermal overload tripped. I've never
seen one "trip by itself" with water in the normal temperature
range.(I'm assuming that since you mentioned opening the "upper panel",
there's a lower one too, so there's two thermostats on your water heater.

I would tend to disagree that the heater overheated. The OP said the
water was cold in the shower in the morning. If the water was
overheated, it would still be hot, or fairly warm. I can shut off the
power to my water heater and 24 hours later still have relatively hot
water (assuming someone did not drain the tank).


The button could have been tripped for a day or longer before the tank
ran out of hot water. Even overheated water cools or gets used up
eventually.

Steve B.