I have a small simple space-saver water heater with a 120V 1500W element. It was working fine for 7-8 years, then stopped working. I changed the element and thermostat control box (the one that clips to the side of the tank) just in case and it worked for another 3-4 months, then died again.
So I called plumber, the figured maybe the tank has an issue and sediments, anode couldn't be pulled out, so we decided just to change to a new tank of same rating/size. Left it over the weekend (this is an office install) and come back Monday morning no hot water.
Power to element 120 V going in. Element ohm rating in the 4-5K ohm and going up. Normally should be around 10 ohm for a 120V 1500W which should draw 12.5A. Same thing that happened to my other 2 elements before that failed. This was brand new tank though, new element, new thermostat.
We are now scratching our heads, as well as plumber, wondering what is going on. He wanted to call an electrician to see if maybe something with the panel but I don't know.
Here's what I do know:
1. The wires from the thermostat (going to element) show 120 V AC
2. When I switch panel breaker off, I am still getting about 1.25 V AC (not 0)
3. The element is showing too high ohm reading, although it is in water (still installed in tank) I would still expect low readings, not that high.
4. I don't think it is electrical issue but then why are my breakers showing 1.25V AC even when off
We suspected maybe hot/cold is mixing somewhere and the tank is running all the time. If it was electrical issue, it would have probably not worked from the beginning. But because it was installed Friday afternoon everyone left, thinking the tank was warming but it could have just been getting to ambient room temperature. So could be it never worked and element faulty from the beginning, or it burned out before the tank filled.
Anyways, at this point... plumber going to change element first. He'll look at tank contents and see if there is any crud or contaminant that could have caused an issue. We are also going around office and checking and disconnecting all things that have both hot/cold where a mixing valve could have an issue and allowing cold to get back in the hot tank, which would then cause cold water to backflow into the tank and cause element to run constantly and thus burn out.
Finally, we check for any leaks to make sure tank is not draining somehow (we have some backflow preventer and other valves which in case of pressure changes they drain directly into some traps so keep water in them)... those would drain slowly without us noticing any puddles on the floors. The water is shut off during the night, we shut back on day. So it could theoretically drain the plumbing in the office including tank.... But I never notice "filling" in the morning, we have water right away so that can't be it.
I know this is an electrical forum not a plumbing one, but I would appreciate knowing if you think it could be electrical before my plumber starts to bring in the electrician and entire army. :-) Thanks!