water heater pilot light issue

[Ruger]

5 days ago the pilot on our water heater went out. Initially I thought nothing of this because we had just had a 2 day wind storm.
I've had to re-light the pilot ~2/day since. It starts up fine, but seems to shut off with the burner once the water gets to temperature.
I've replaced the thermocoupler resulting in little or no change.
Can anyone give me advice on what could be causing this?

FYI: Its a State Select (8 years old), low boy, 40 Gal, Gas Burner.

Thanks,
Ruger

[Cass]

If you have replaced the thermocouple and you did it right, you can try again in case it is bad which is a long shot. If the problem persists it is most likely a bad gas control valve and it will need to be replaced. Does the pilot flame seem adequate.

You may want to consider replacing the whole heater if it is 8 Yrs old. Most State heaters I run into don't last a whole lot longer than that.

[master plumber mark]

State Select water heaters are junk ...like cass said...

the high limit circuit in the gas thermostat has gone bad on you ......

the part is about 95 bucks...

but like he already stated they are not worth the trouble..

.

[hj]

Something could have changed causing the pilot failure. Until you know what is really happening, it is not the thermostat's high limit or the pilot would not stay lit in the first place which would also happen with a bad thermocouple. It could be a dirty or misdirected pilot flame not impacting the thermocouple correctly, or something, such as a misfiring main burner, overheating the thermocouple.

[Ruger]

Thanks for the info everyone. Here is a little more from my end, if it helps.

The pilot light is hitting the thermocoupler directly, and the tip of the the thermocoupler glows. The pilot light itself is blue.

The main burner has flickers of orange flame, overall it seems to be a pretty messy/unstable flame. Could this need cleaning?

Last night afer posting I lit the pilot, I also messed a little with the top of the flue. The pilot has stayed on since, even through a few burner cycles?

I appreciate the advice on getting a new wh. Good to know that state select heaters are junk. I'm hesitant to buy a new one because we've sold this house and we are moving out/closing in 8 days. However, I don't want to leave the new owners with a lemon.

Thanks,
Ruger

[Verdeboy]

This works for furnaces, I don't see why it wouldn't work for HW Tanks:

To test your thermocouple:

1. Turn down thermostat.
2. Leave gas valve on and blow out the pilot.
3. If you hear a "click" in 25 seconds or less, your thermocouple is bad.
25-60 seconds, it is good.

You can buy a pilot "broach" at a good plumbing or HVAC supply store. It is a special tapered wire with a little handle for cleaning out pilot orifices.