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Discussion Starter · #1 ·
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.
 

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I don’t think you could have caused it if you let the water heater fill back up before you turned the breakers back on. If you have an ohmmeter you can check the heaters. First turn the breakers back off. Then remove both covers on the side of the water heater. Once off you should see both heaters remove the wires from the heaters. Then check to see if you have continuity between the two terminals that you took the wires off. If you do not have continuity the heater is bad and needs replacing. If you do have continuity check to see if you have continuity between one of the terminals and ground if so the heater is bad and needs replacing. If not the heater is ok check the other the same way. If both of the heaters check ok replace both thermostats.
 

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No hot water= bad upper element
not enough hot water like 5 to 10 min worth= bad lower element

also there are resets on some of the newer thermostats once you take off the cover , and peel back the insulation you may see a red reset button. Always do this with power off its very easy to get shocked from the terminals. If it is the reset and repeated resetting is needed replace the thermostat
 

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Yes yes yes all are correct but don't forget about the broken dip tube, if all heating elements work as described above then you have to pull the cold water inlet tube to make sure it goes to the bottom otherwise it will immediately mix with your outgoing hot water and feel cold.

Generally speaking if one of your heating elements fail you will still archive the same temperature of hot water as before but will not have a fast recovery rate after or during usage.
 

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Discussion Starter · #5 ·
Updates

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?

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Discussion Starter · #7 ·
Though your particular heater is too new for this but in the 1990s there was a big lawsuit with AO Smith, it was a very common problem along with the anode recall. Here is some info to check on.
http://diptube.info/topics.html
Thanks for this. I should have mentioned that I had an older unit that was affected by this. A repair was done under the recall terms and the unit was fine until it finally started to leak. At that time, this unit was acquired under the pro-rata warranty. It has been find since then.

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.

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.

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Discussion Starter · #11 ·
Thanks for the responses. I will now check voltages and try to see if the thermostat(s) are the culprits. I now think I understand enough to do this. I do worry about using the volt meter on such high voltage but that is mostly because I have almost no experience testing anything other than continuity.
 
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