hot water heater thermostat keeps burning out


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Old 07-20-13, 01:24 PM
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hot water heater thermostat keeps burning out

about a year ago my hot water heater upper thermostat and upper element went out and i replaced them. have not had a problem until just recently.

the thermostat continues to trip and after checking it, it is the upper thermostat that has gone bad. problem is this has now happened three times. the elements and lower tstat test fine.

what could be the reason for this? texas summer heat?

and to compound my problem my hwh is in my very difficult to access attic.


any troubleshooting advice would be much appreciated...
 
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Old 07-20-13, 05:11 PM
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Welcome to the forums.

The top thermostat has a safety stat (red button) that trips or "pops out" when the temperature of the water in the tank rises over 180 degrees.

Usually the cause of overheated water is a lower heating element that has a leak to ground. You need to turn power off to the heater. Disconnect both wires to both elements. Take a volt/ohmmeter and check between the terminals and you should measure between 5-20 ohms. Now check from each screw to ground (the tank or heater nut) and you should see no resistance. Any reading at all means defective element.
 
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Old 07-21-13, 10:54 AM
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thanks for the response. i have done this several times with a hot water heater tester, not an ohm meter. it continues to show that the elements are fine and have no leak to ground.

is it possible the reading i am getting could be wrong?
 
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Old 07-21-13, 10:57 AM
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I use an ohmmeter. I have no idea what a hot water heater tester is.
 
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Old 07-21-13, 11:03 AM
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it is a cheap tool from home depot that checks circuit continuity and ground leaks.
 
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Old 07-21-13, 11:16 AM
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If you are referring to that yellow Camco continuity tester........forget it. That is a very basic continuity tester. It will check continuity of a thermostat or element but we're looking for leakage.

Your how water heater elements are always live on one side and the other side is switched on by the thermostat. If the element internally shorts or has leakage to ground or to the water then it will continue to heat the water continuously until the hi heat stat trips.
 
 

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