Trouble With Electric Hot Water Heater

whitedavidp

Hot sure to place this in Appliances, Plumbing, or Electrical (or somewhere else). So here goes. Pardon any duplication or confusion...

Have had my electric hot water heater now for several years. Of recent I have noticed that while there is hot water, there isn't alot and it isn't that hot.

I believe this started after I turned off the water to our house while we were away for an extended period. Before I did this I turned-off the circuit breakers to the water heater as I was sure having it on might cause problems. I did not drain the tank but I did leave all the faucets on it the house. When we returned, I turned on the water, closed all the faucets, and reapplied power to the heater (in that order).

This is a typical 60 gallon heater with 2 elements. I am assuming that one element is shot. But how to test this theory? Also could it have been caused by my turning off water to the house?

Thanks.

DangerMouse

it's likely the bottom element, yes.

DM

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whitedavidp

Thanks to all who have responded. Your ideas have been quite helpful. I managed to get my ohm meter working and have performed the electrical checks. I fully expected that one of the elements would be bad even though this is a fairly new water heater (2-3 years). But both elements have conductivity and neither indicate continuity to ground. I did note, however, that the upper thermostat was set on the marked line at 125 degrees but the lower one was set lower at maybe 95 degrees. I did not do this myself so maybe it came that way from the factory. Or maybe a renter did this and never told me. Is this a correct way to set these things? I turned the lower element up to 125 on the marked line. I know that this is how the heater is set in our other home.

If the temperature setting is not the real issue, then it seems like the dip tube or the thermostats are the next thing to check out. How likely are these to be an issue with such a new AO Smith unit?

Thanks

DangerMouse

did turning up the bottom thermostat help?

DM

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whitedavidp

I didn't get a chance to check out the results of the temperature change as I had to leave after doing the adjustment. I will go back with a thermometer and see what the water temp is. Then I will run the water for a long time and see how long the hot water lasts.

I should also point out that the measured resistance on both elements was 13-14 so that also seems to indicate that they are fine.

Thanks

hychesee

Yeah that resistance works out to be 4500 watts so all is good, that lower temp setting sounds like the problem. Now put a tell tale piece of hidden tape or something else to indicate if it has been tampered with in the future.

Stubbie

It is likely that both thermostats have red reset buttons. Make sure these have not tripped on the thermostats. If so reset and see what happens. I doubt it is the temperature setting since you used this for years without complaint. Most likely a thermostat problem and likely the lower thermostat.
Both thermostats do not heat at the same time so when the top reaches it's setting it closes a circuit to the lower thermostat. Check voltage at the lower heating element across both hot wires when it calls for heat. Should have 240 volts. If not the upper thermostat may be faulty or it could be the lower one. Depends on where voltage is present and where it isn't. No voltage on the wires to the lower thermostat at the upper thermostat terminals would lend to a faulty upper thermostat. Voltage at the connection to the lower thermostat but no voltage at the lower heating element, then problem with the lower thermostat.

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Stubbie

whitedavidp

Thanks for your response. I rather doubted the temp setting was the problem too. The two thermostats look a little different and only the top one has a reset button which had not popped-out but which I pressed anyhow (with no movement). I have no idea how much the thermostats cost but it may make sense to just replace both if I can determine that they are the culprits. Your info will help me figure that out. Cheers!