Electric water heater diagnosis

[JellieBean]

Good morning experts,

I have a standard cylindrical electric hot water heater with a problem. It's 15 years old, in great physical shape, and all 4 relevant parts have been replaced at least once over the years. Right now, the top element is working (I can feel the heat) but the bottom isn't. Neither the circuit breaker nor the reset button on the top t'stat are tripping. I replaced the bottom t'stat last night with an old one I had tucked away in my tool box but it didn't help.

My questions are:

1) Was that the likely culprit and my old tool box t'stat probably bad? 2) Is the upper t'stat actually the problem? (Remember, the reset never kicked.) 3) Is the bottom element the real problem? (Please tell me no.)

I know diagnosis would be easier with the proper meters, but I figure it's cheaper to by replacement parts on an educated guess than buy the equipment and then buy the replacement parts on a highly educated guess.

Thanks and happy Easter, DJ

[Robert Barr]

For less than $30, you can buy an adequate digital meter AND a new stainless heating element. Just be careful, double-check that you've killed the juice EVERY SINGLE TIME you do anything, and follow the directions on the website.

Once you understand how these things work, it's easy to hunt down the problem. It could be the upper thermostat not switching, or the lower element is shot. Both are easy to test; I'd suspect the lower element first.

[Jack Alexander]

When temperature in the tank drops, the top heater cuts in to provide quick heating of water in the top portion of the tank. While this heater is working the bottom element is off. Once the water at the top of the tank gets up to the set temperature and shuts off, then the bottom element comes on to heat the water in the lower portion of the tank. Simply put, if one element is on, then the other one is off. They both don't work at the same time.

Jack

JellieBean wrote:

[me]

You can buy a neon test light for about $2 at any hardware store. If there is voltage going to the element, then the t-stat is ok and the element is bad. If no voltage there, then the t-stat is bad (or a wire is broken). Why are you making this job so complicated. Buy a test light. You can even get test meters for under $20......

[Henry77]

As an addition to your description - if the top element dies neither will work and you will have no hot water.

shape, and all 4

[JellieBean]

Got it! It was a bad lower element.

Thanks guys, DJ