Electric Water Heater Tripped for No Reason - Why?

fooltergeist · 2004-12-16T13:16:26+00:00

This morning was the coldest day of the year in the Washington DC area- a bone-chilling 21 degrees F. I stepped into my shower and lo andbehold - no hot water! I scurried to the basement, checked the maincircuit breaker and the water heater/deep well pump breaker andeverything was on - they did not trip.I went to the water heater - a Bradford White Hydrojet that is lessthan 3 years old - opened the upper panel, pushed the red reset button,heard it click, and waited a few minutes. Later, I felt the copper tubeon top warming up again and when I checked the water faucets, the waterwas starting to get warm. I had to leave for work so I didn't have achance to see if it would trip again. I'm now in the office for 3 hoursand the wife has not called, so I am assuming things are back tonormal.I have done a fair amount of reading on the subject but, given therelatively young age of this unit, I don't believe there is anythingwrong with the thermostats or the heating elements.So my question is - is this just a fluke, an act of God, a one-timerandom event that may never happen again? What could have caused it totrip without the main breaker going off? Could the cold weather haveanything to do with it? What about the fact that our water source is adeep well pump?I guess I'm just looking for a rational explanation, so that I willhave peace of mind if the heater switch does not trip again.Thanks for any insights, tips, comments, etc.

J

Jeff Wisnia 21 years ago

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

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Steve B. 21 years ago

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.

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Filipo 21 years ago

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!

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