Hot water tank pilot/control valve

[Wiltshireboy]

My house s fitted with a 50 gal AMERICAN hot water heater. On Sunday night I noticed hot water venting from the overflow into the yard. I replaced the pressure relief valve turned the gas back on only to find that the pilot would not light. As the pilot nozzle and thermocouple and the door gasket looked a bit sad I fitted new door complete with all the various bits. The pilot would light but would not stay lit. As all possible defective parts had been replaced I fitted a new control valve. It took a while to get the pilot to light and stay on but after about fifteen minutes everything came on water was heating nothing was being vented or leaking and hot water was restored. Wife woke me this morning to tell me the water wasn't hot enough. Pilot light is out fiddled about and it relit, main burner came on,an hour later it's out again, I'm wondering if this could be a pressure issue? Any ideas anyone?

 

[Woodsy]

Is there any water in the bottom that could be choking off air to the combustion chamber? Some models it does not take much to obstruct air flow. It just seems like the two events should be related.
The relief valve, usually there is a secondary problem like a bad expansion tank and or bad pressure reducer valve if your on city water. I would check your water pressure. Should have no more than 80 psi.
If the water is over ten years old, might be time for a new one anyways

 

[Wiltshireboy]

There is no sign of a leak, water pressure in the area is quite low. The only odd thing is that the main burner flame does have an orange tinge to it, could there be a leak that only opens up when hot and traces would disappear by evaporation before the tank cools enough to access the underside? It was suggested that the main burner might be blowing the pilot out when it came on and then once the water reached temp the burner would shut down but not relight because the pilot was out?????

 

[Woodsy]

So you mentioned the thermocouple looked rough you replaced it? A little orange in flame is okay but should be mostly blue...make sure there is plenty of air supplied to the area...try opening doors and seeing if flame changes....and not usually leaks under hot conditions only so the tank must be fine. Is it a Power Vent or Atmospheric? Power vent has pvc vent and atmosheric has galv pipe vent