Hot water tank tripping (melting)

[expat]

Hi, No hot water yesterday, I checked the circuit breaker (OK) then the reset button on the tank (Moffit) and it re-set and all was well.

This morning there is no hot water again. When I checked the re-set the plastic flap cover had partially melted and smelt of plastic.

I have not re-set it. Could this be the element or the re-set over heat switch itself?

I have yet it investigat further, any ideas on testing. Thanks.

 

[ragtoplvr]

It is not unheard of for a connection on these to become loose and heat. 30 ish amps makes a lot of heat. Elements failing normally go open or trip the breaker. Normally

All parts should be available. However if over 10 years old and you can afford it you might want a new better insulated one.. If you repair make sure the over pressure vent TP Valve is working just in case.

You can also attempt to replace the magnesium strip, unless you break that loose when the water heater is new and put good pipe goop on it getting one out after 10 years usually not possible.

Rod

 

[WyrTwister]

Be sure to take the time to turn the power off , before you start fiddling with it ! Lets be safe , out there .

Several things can be wrong .

A - Loose / bad / shorted / grounded connection on any of the wiring , including the incoming power .

B - Defective / shorted / grounded heating element .

C - Defective / shorted / grounded control / thermostat .

There may be others I did not remember .

Source a Volt - Ohm - Amp meter before you start trouble shooting . Without one , not much you can do except a visual and maybe tighten screw terminals .

If there is any sign of leaking , very good chance you are going to have to replace the whole water heater . Try to drain as much water from the tank as you can . Water is heavy and makes removing the tank a difficult job .

 

[expat]

Looks like the problem is with the thermostat.

All wire connctions are sound.

 

[WyrTwister]

Can not tell from the photo , is the thermostat burnt ? Does it smell burnt ?

Has it gotten wet ?

https://www.homedepot.com/b/Plumbin...er-Parts/Thermostat/N-5yc1vZckr8Z1z0u2lo

 

[expat]

Yes burnt on the left side (down side in my sideways photo) the plastic cover had melted.

Locally only an eastman upper t'stat is available, it looks slightly different to the one in this Moffit heater but not significantly.

 

[expat]

Nothing is wet.

 

[expat]

Interesting all those upper t'stats look the same in your link, but different prices ??

 

[Donald]

replace thermostat

 

[sloinker]

High current draw could have killed the thermostat. Drain tank and change upper and lower elements along with the thermostat. If tank is more than 10 years old I would just change the whole shebang as it will be scaled and on the way to weeping/leaking at the bottom.

 

[expat]

I replaced the burnt upper t'stat and things are working, so far.

The tank is 3 years old, so it should be in reasonable shape.