I have a Craftsmaster 40 gallon electric water heater that is approximately 13 years old. Once it got cold outside and we started taking more hot showers, I felt like we were prematurely running out of hot water. So, I finally decided to raise the temperature on the heater yesterday afternoon.

When I woke up this morning, the hot water was barely lukewarm. I thought maybe I had adjusted the temperature in the wrong direction, but I checked the potentiometer on the tank and it was indeed at a higher setting. Neither the reset button nor the breaker at the circuit panel appears to have been tripped.

Is it possible that when I adjusted the temperature up on an already old heater, I caused a surge or something that damaged the control circuitry? If so, is it possible to repair it or should I just replace the heater at this point?

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    It's possible the wiper on the thermostat is rusty and you just ran it up on some non-conducting corrosion. I'd wipe it back and forth through the full range at least 5 times. Also, when setting water heater temp, think legionella. Nov 22, 2019 at 22:19

1 Answer 1


Electric water heaters are easily repairable if you can get the old heating elements out of the tank. If they get too corroded, you may not be able to remove them without damaging the tank.

But, that is a bit premature. You need to test the resistance of the heating elements to determine if they are good. You can also check that the thermostats are supplying voltage to the elements. Note that this requires working around live, unshielded 240v connections, so you need to be careful and be sure it matches your comfort level.

The thermostats and elements are pretty standard and you should be able to find replacements at a typical home store.

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