Water Heater - flame out

[Jibe]

I installed an AO Smith 50 gal natural gas water heater last June. Model GDVS 50.

Its in my basement, and its direct vented to the exterior wall of the basement. Its worked fine for the last 6 months, but in December, we had no hot water because the flame had gone out. I relit it w/no problem, following the ingition sequence posted on the heater. Didn't seem to have a problem with the gas supply. I haven't had any problem with the gas furnace in the basement, which is tapped off of the same black iron gas pipe. Since December, I've had to relight the flame about every 2 week. Keeps going out. I can't figure out why. Today it went out. I relit it just fine. An hour later, it was out again. Relit it again, lit just fine - but 10 minutes later - out again. I relit it a third time , and stuck around to watch it. The pilot ignites fine when I click the piezo lighter. After a minute I turn the thermostat up slowly, and the flame came up fine. But as I stuck around to watch, I noticed that the blue flame started to get flecks of yellow & red in it, and the flame kept getting yellower & yellower. Finally after about 2-3 minutes it suddenly went out. I can't figure it out.

I have 2 thoughts. 1. Its very windy today. Is this affecting the flame (though it doesn't explain the past incidences when the flame went out on calm days. The basement is old and is moist, and the run of gas pipe feeding it is at the lowest point of the whole gas service. I did not install a dirt leg when I extended the black iron pipe. Could I be getting moisture in the gas line?
Thanks in advance for help.

[master plumber mark]

the gas valve is defective....

their is a high limit sensor in the valve that senses
the temp and it has burnt out on you....

you will need a new gas thermostat valve ....
its probably under warranty,,,,


you can try the thermocoupling first if you wish
but it sounds like the latter to me

[Jibe]

thanks for the reply. Next question - Instead of trying to relight it, so my kids can get hot water for a shower. Should I just shut this down until I can get it repaired? I don't want to do anything risky here.

[jadnashua]

Do you have a CO detector? This tank gets combustion air from inside, and has power vented? Or does it get air from outside? If air from outside, ice or snow could be giving those symptoms, too - basically, not enough air. What is the room like? Does it have enough air?