go here and check your warranty status. I have less than a year warranty left and when I called their customer service they asked for a description of my problem and are sending replacement parts with replacement instructions. The fellow I talked to was very nice and knowledgeable. They are sending a pilot assembly (which includes the thermocouple), a new temperature gauge and a cleaning kit. apparently there a known issues with this model and they have found annual cleaning resolves/prevents them from occurring. I thought this was really nice, since I will be out of warranty if this happens again in a few months or longer.
thanks to all who posted this problem. it's 2:30 am and i think the pilot will stay lit now. i have replaced everything on this piece of sh&* and finally searched "A O smith wont stay lit"..... and found the cure. i never thought there would be a screen to clean, my wife was ready to buy a new tank.
I have an AO Smith Promax water heater that will not stay lit. I called Customer Service and did everything I was told. I even had the Master Plumber come back out and he replaced the burner and gas control valve. Now 3 months later its doing the same thing.. Again he replaced the gas control valve and I took a hot shower.. Got out of shower and pilot is off again... AO Smith says they get calls all the time about this, but that its just because its located in the laundry room. Duh.. what if it was in the attic or basement? more lint and dust there than in the laundry room... DO NOT BUY AO SMITH.... Their Customer Service people read from a list of suggested fixes which none of them work. PRODUCT IS DEFECTIVE.....Plumber bills are killing me.. I think I will switch back to Electric. At least I had hot water and no pilot to light 6-8 times a day.