A little electric water heater help please...

[Bad Wolf]

During the shoulder season I sometimes switch over to an electric water heater. Lately the wife has been complaining about lack of hot water, and when she went to fill the tub this morning there was some sediment in the water. I checked things out: I have 240 to the main thermoset control at the upper heating element. I have 240 to the upper element when the temp is below the set point and I can hear the water "popping" as the element heats up. The contact to the lower element shows 240 available to the lower thermostat if the upper is not calling for heat, but as soon as the upper kicks in this drops to 120 volts. I thought that both elements used 240.

Regardless I don't think the lower element is working because the lower half is always stone cold, so I'll replace that today.

So is the upper/lower set up normal? Is this something so that if one is running the other doesn't need as much?

Also which one do you set higher or do you set both the same?

Thanks

 

[heat seeker]

Just a guess - maybe when the upper is on, it only breaks one leg to the lower. Are you measuring across the lower element, or to ground? Have you pulled the wires off the lower and done a resistance check?

 

[begreen]

http://www.familyhandyman.com/plumbing/water-heater/diy-hot-water-heater-repair/view-all

 

[Seasoned Oak]

It also may be one of the thermostats that is not working, check the element with an OHM meter to determine if its providing the right resistance, before draining the WH and actually taking it out ,which is a waste of time if there is a problem with either the upper or the lower thermostats.

 

[greg13]

Turn the power off first. Disconnect the elements and check them with an ohm meter. My guess would be a bad element, usually the bottom one. Depending on the age of the heater it may not be worth messing with.

 

[semipro]

I'd recommend checking out this site www.waterheaterrescue.com There's some pretty good info there.
Electric resistance water heaters can typically be repaired easily as long as the tank is not leaking.
I'm guessing your tank has filled with sediment to the level where the bottom element is surrounded by the sediment and burned out. If so, you can remove the bottom drain valve and the bottom element and flush the sediment out, then reinstall a new element and the drain valve.

Edit: check out this thread: https://www.hearth.com/talk/threads/hot-water-heater-leak.152377/#post-2059330

 

[Seasoned Oak]

Keep in mind ,Only one element will run at a time. The lower element will not come on until the upper one is satisfied. Usually 4500 watts each one. If the lower element is not working either its burned out or the thermostat is bad and not activating it. .In this scenario you will only have a few gallons of hot water in the upper half of the tank.

 

[Bad Wolf]

The lower element was indeed the culprit. I flushed the sediment out drained the tank (20 minutes) replaced the element (12 bucks and 5 minutes) and refilled the tank (10 minutes) and Bob's your uncle. The element had shorted out which is why I was seeing 110 volts when the upper was on. Now I get nothing until the upper shuts off.
The tank and timer were free 5 years ago on Craigslist so this is still a pretty good deal.

Thanks