I had a problem with my water heater. Its only 3 years old and when it got turned back on it worked for a bit then stopped. I then couldn't get the pilot light to stay on... held for many minutes. Being uneducated in water heaters I just assumed it was the thermocouple. As I started to dissasemble I noticed the sticker that said one time use over heat circuit. I then thought maybe it overheated. I took the control off and the thermocouple. I replaced both... fired it back up and again it only worked for a while before a few min then shut off and I now have the same problem. The pilot light won't stay lit. I started to investigate and found the overheat circuit was good... not the problem. I then wonder... do thermocouples go bad?. and if so is there a way to test them? Please help. Thank you, Charley

I had a problem with my water heater. Its only 3 years old and when it got turned back on it worked for a bit then stopped. I then couldnt get the pilot light to stay on...held for many minutes. Being uneducated in water heaters I just assumed it was the thermocouple. As I started to dissasemble I noticed the sticker that said one time use over heat circuit. I then thought maybe it overheated. I took the control off and the thermocouple. I replaced both...fired it back up and again it only worked for a while before a few min then shut off and I now have the exact same problem. The pilot light wont stay lit. I started to investigate and found the overheat circuit was good...not the problem. I then wonder...do thermocouples go bad?...and if so is there a way to test them? Please help. Thank you, Charley
Thermocouples are pretty robust. They can be tested if you know the type i.e.. J,K. a simple test may be to check if it is a closed circuit . I don't remember what resistance should be measured . You should be able to Google it. Check for any loose wiring.

Thank you. I just replaced the new thermocouple with another new one... and it works. Go figure. This thermocouple is the standard whirpool water heater one. Copper tube and I believe it works with dissimilar metals... one expanding at a different rate than the other thus moving the silver tip just enough to open pilot lite valve.. Not too sure but that's my best guess. Anyway I'm showering with hot water today. Thanks for your help. Charley