Water heater thermostat switch

[Yazoo]

My water heater was working fine on propane but the electric did not work. I checked all the usual suspects, on/off rocker switch, circuit breaker, pushed the reset buttons and even checked the electric element to ensure it was not burned out. So I pulled the cover off the thermostat/Hi-limit resets and found that my T-stat/Hi-limit switch assembly had burned out. What would cause that to happen?

[nunya]

Interesting...........let us know if ya figure it out, age of it?

[ole dude]

Loose connections on the control circuit for the heater can be a cause. Also those are a bi-metal strip that that heat up from tank temp then open to turn heater off. If they dont open fully then you can have a slight power supply to the heating element which will cause the limit to get hot and eventually fail.

[sreigle]

Yazoo, for my future reference I'd be interested in hearing how you tell a particular thermostat has burned out, if you don't mind telling me. I can operate a VOM for both voltage and resistance but am not particularly electrically literate so maybe it's beyond me. Thanks.

[Yazoo]

Steve, when I pulled off the cover to expose the breaker you can see that the wire (bi-metel strip) between the two contacts was melted so the wire was not conected at both ends. Not sure how else to explain it

[sreigle]

Thanks, Yazoo. I guess I better go take a look. I was thinking ours had a high and a low and they are both behind black rubber plugs. I'll see if I can pull those out and look. Thanks.

[grooving grandpa]

Can someone post a picture of their water heater. My switch is on the lower left, but where is the "by- metal strip" and how do you get to it?
Thanks Lou