Electric Water Heater Tripped for No Reason - Why?

[BGBevill]

Usually, stats sticking or being out of calibration will cause the red button to trip. I am thinking that an element could cause it, but only under certain circumstances. Anyway, to replace the elements, cut off the power to the tank and the incoming water. It is possible to replace the elements without draining the tank completely, but if you have never done it, I'd recommend draining the tank. Once you have it drained, the elements either screw out or are attached with 4 bolts on some models I have seen.

Keep in mind that the red button is a high limit and is a safety device. Do not continue to experiment with a solution to this problem. Ever seen on the news what is left of a house when the water heater blows?? Not very much....think about it.

Bobby

[Jeff Wisnia]

Is there ANY possibility that you might have miswired something when you replaced the thermostats? Did you have or make an accurate diagram of just which wire went to which terminal on the two thermostats before you removed them?

I should have asked before, but is the "red button" you refer to

*really* on a high temperature overlimit thermostat. i.e. is it part of the upper thermostat assembly or otherwise on something in thermal contact with the tank shell?

I'm frustrated, 'cause I know that if I was on the scene with my clamp-on ammeter/VOM I'd have been able to diagnose it much better.

BTW if you *are* going to change out the elements, and they are threaded into bosses on the tank shell they'll have a large hex section on them and you'd be well advised to pick up an "element socket wrench" to unscrew them with unless you have a socket of the proper size already. They usually don't like to come out if you go after them with a pair of Channelock pliers or an adjustable wrench, and you can screw up a new element trying to tighten it firmly without a socket wrench. Those element socket wrenches are usually stocked right near the elements and only cost a couple of bucks.

Good Luck,

Jeff

[Steve B.]

An experience plumber can sometimes replace an element without draining the tank but I would never try it myself and I have done about 20 over the years. Go ahead and drain the tank then replace them and save yourself a headache.

Stee B.

[Filipo]

The red button on the upper thermostat did not pop this morning, and that may have been because I re-adjusted the 2 brand new thermostats to their factory presets. Both thermostats are so-called "Apcom Style" thermostats made as OEM by Camco. They are currently on sale at all Home Depot stores for 3 bucks apiece, which makes me wonder if they are crappy because they are so cheap, or they are so cheap because they are so crappy. They are the exact same replacement models that came with my Bradford White water heater, so I'm pretty sure my wiring is the same, except I had a little problem tightening the screw on the black wire of the lower stat because the screw offered some resistance so I forced it and may have stripped it a little bit, but there is still some electrical contact, I think.

Each thermostat has 4 settings - "Hot", "A" "B" and "C". "Hot" is the factory preset at 120 degrees F. I turned the white knobs to "A" before I installed them because I was guessing "A" might be at least 135 degrees F, which is supposedly the minimum temperature needed for the clothes washer. Then I installed them. Shortly thereafter, the hot water temp zoomed up to higher than normal and the red button tripped. I reset the red button. Then I turned the white knobs back to "Hot" and I heard a distinct click on the upper thermostat, as if it was closing (or opening?) as I was turning the white knob back to "Hot" from A"".

It seems to that my act of changing the factory presets from "Hot" to "A" prior to installation may have confused the thermostats. Perhaps I should have installed them with the factory presets at 120 degrees F before I decided to change anything. Just as a car needs a break-in period, perhaps the thermostats need to be installed first before they should be adjusted temperature-wise. Does this make sense?

Sorry for the long-winded explanation. I'm pretty happy now at the 120 degrees F factory settings, as long as they don't trip again. So I'll suspend the element replacement project for another day. Thanks all for your support!