I have a State water heater that's around 13 years old. About a month ago, the pilot light went out randomly and I was able to relight it with no problems. A couple of days ago, the light went out again but I was not able to ignite it again using the built-in igniter. After some research, it seems like the likely culprit could be the thermocouple. The model number of the heater is GS650UBRT100.
I found the parts catalog and was able to find the original part through Sears PartsDirect (http://www.searspartsdirect.com/part-number/9000056015/0042/153.html). However, if I order it now, it probably won't arrive for another week.
The Home Depot has a generic thermocouple by Honeywell, and I was wondering if I can use that instead: http://www.homedepot.com/p/Honeywell-24-in-Universal-Gas-Thermocouple-CQ100A1013/202216463
The manual refers to my water heater's part as a thermopile, but the parts catalog says it's a thermocouple, so I'm confused as to what it actually is, and if it's interchangeable. Would I be ok with getting the generic thermocouple for my specific water heater? It says it's for 30mV systems, but I can't find the specification for my specific model.
This is the heater's manual: http://www.statewaterheaters.com/lit/im/res-gas/186221-004.pdf
And the parts catalog: http://www.statewaterheaters.com/lit/partslist/res-gas/186298-000.pdf
Also, what are the chances the problem is caused by another part, such as the pilot assembly kit or the igniter? Should I start with replacing the thermocouple and go from there?
On an unrelated note, I've attached a picture of my water heater. I noticed that there's a pipe on the very right with the valve closed. What is this pipe, and why is the valve closed? Thank you in advance.
Best Answer
First, I agree with the above comments: I use a 400 fine-grit sandpaper to clean off the existing thermocouple tip and I clean off the pilot tip as well.
As a separate precaution, I would check the spark on the igniter assembly by disconnecting it then watching for the small blue spark at the hand-button (DUH, only after turning off the gas!)
Yes, you can use the Honeywell 30mV t-couple with the State if/when the threads in the gas control valve seat fit.
Lastly, note that some State water heaters have a high-temperature shunt soldered in-line with the thermocouple. These are a retrofit part to repair problems in hot-weather climates (like Arizona and Southern Nevada.) In that case, the thermocouple with the shunt 'ignores' high ambient temperatures in garages, etc. I have had to replace my State water-heater thermocouple a few times because the shunt resistor cracks. Of course the cracking problem only occurs in cold, winter temperatures.
The parts list for your heater is found here; and it looks like yours (at least originally) did not have the high-temp shunt resistor version of the thermocouple. Your thermocouple #9000056015 is manufactured by AO Smith and (for example) could be purchased here or elsewhere.
Bottom line: go get the Honeywell and a 2nd push-button igniter; order a 2nd AO Smith thermocouple online; clean and test your existing ones if you are up for it....please post back your progress.