Water Heaters - pilot blows out when water reaches temp

hi there- my basement got a few inches of water recently, and since then I've been having trouble with my water heater staying on.

there was enough water that the pilot went out from the flood, and after we cleaned up the pilot wouldn't stay lit at all, so I replaced the thermo-coupler.

this seemed to work for a few days, but then it started going off again. I now light the pilot before bed which gives me hot water for morning showers, and then light it again when I leave so that there is water to do dishes/etc when i get home.

I've determined that the pilot goes out when the main flame shuts off.

I've tested this by lighting the pilot, turning the gas on, and letting it heat for a while, then going and turning the thermostat down low enough that the flame shuts off. this blows the pilot light out every time.

i've seen suggestions that something may be in the pilot tube - and I'm thinking my next attempt to fix this will be to remvoe the tube and clean it out.

any other suggestions?

More than likely the pilot burner is dirty and needs to be disassembled and the pilot orifice cleaned. When pilot burners get dirty they are susceptible to being blown out when the main burner shuts off.

You can probably observe that happening if you observe the pilot and main burner operation wnd repeatedly cycle the main burner by turning the thermostat up and down.

The orifice for the pilot burner is not much larger than a human hair...so my money is on a clog. Dissassemble the fitting where the 1/4" aluminum tube connects to the burner itself...that is where you find the orifice.