Possibly OT: Water heater problem

[BiggestMike]

My electric water heater is on the fritz. Unit is probably 5-7 years old and looks to be in good shape.

The water temp will increase beyond where I would expect it to be given the thermostat setting, to the point where it kicks off, then I hit the reset button and it starts all over again.

I'm assuming this is just the thermostat(s) and I'm going to order replacements (there are two). I figure I just swap them out and the problem should be solved. Right?

Could it be any more complicated than this? Thanks for any tips. Sorry if this is OT.

 

[p_mori7]

electric water heaters usually have one thermostat, but two heating elements (upper & lower). Up here in Canada anyways.

 

[CitadelBlue]

electric water heaters usually have one thermostat, but two heating elements (upper & lower). Up here in Canada anyways.

yep .. Lowes has a kit .. $48 for 2 elements and 1 thermostat .....

 

[Greatbear]

Most water heaters use a pair of thermostats and an upper and lower element. The thermostats are single pole, switching the power to one side of the element load. The safety is double pole. If an element fails by shorting internally and the heater is 240volt powered (in most cases) the unswitched side will continue to power the element through the grounding means at some level of power until the safety switch pops. Replacing thermostats will not fix this issue. Simple test is to turn off the breaker at the panel and use an ohmmeter to check for continuity between each element terminal and ground. There should be a completely open circuit, no measurable resistance or short.

If the water heater had run low or empty of water at some time while the power was still applied, the elements can be damaged. The resulting meltdown of the elements can cause a short internally to the element sheath.

 

[mr48chev]

A bad bottom element will often cause similar symptoms. If you have hard water there may be a lot of deposits in the tank that look like white gravel. That has to come out before you put a new element in. If it is there that is.
There should be plenty of info on the net showing how to test a water heater element.

 

[WVBrady]

Most water heaters use a pair of thermostats and an upper and lower element. The thermostats are single pole, switching the power to one side of the element load. The safety is double pole. If an element fails by shorting internally and the heater is 240volt powered (in most cases) the unswitched side will continue to power the element through the grounding means at some level of power until the safety switch pops. Replacing thermostats will not fix this issue. Simple test is to turn off the breaker at the panel and use an ohmmeter to check for continuity between each element terminal and ground. There should be a completely open circuit, no measurable resistance or short.

If the water heater had run low or empty of water at some time while the power was still applied, the elements can be damaged. The resulting meltdown of the elements can cause a short internally to the element sheath.

This is a common problem, even in you do not let the water level drop. I burned up a couple of breakers before I realized what was wrong, because they are not rated for continuous duty.