suitable interim solution?
I have an FG************ model American Water Heater Company Flame Guard 50 gallon heater, installed by Keyspan in 2004. From what I've read here (I'll admit to not reading all 37 pages of this thread) AMC makes the despised Whirlpool unit this thread is about and the similarities between my unit and the one discussed here are enough that for the sake of argument, we can assume my unit is the same as the Whirlpool.
Several days ago, my family woke up to no hot water. I was able to relight the pilot and the unit started up but failed again later that evening. After several days and increasingly frequent restarts, I called the manufacturer today and they're sending me a new thermocouple. In the meantime, my family would like to avoid cold showers tomorrow morning and in researching the problem, I found this thread.
In prep for the thermocouple replacement, I scrubbed the vent thing at the bottom from inside and out with a toothbrush, but did not find it to be clogged. (Surprising, considering it's been 7 years without a cleaning.) I reassembled the unit with the original thermocouple in place and started it again. It shut off, pilot and all rather quickly.
When I lit the pilot and started it again, I noticed through the view port that the large flame from the burner was engulfing the pilot, starter, and thermocouple. I had never looked before, so I don't know if that's normal or not.
It seems counterintuitive to me to design it that way intentionally, but maybe the tolerances of the thermocouple are so great that being constantly submerged in normal burner flame is not hot enough for it to trip the safety shut off, but out-of-control heat/flame is.
To the point of this post... Using the gas control valve outside the heater, I restricted flow to the heater's control valve by turning the supply valve to half-off while looking through the viewport. This reduced the diameter of the burner flame to about 80% or normal to the effect of the thermocouple no longer being submerged in flame. Since then, the burner has cycled on and off properly several times, the pilot staying lit each time. We've had two showers and run the dishwasher and everything appears to be operating as usual.
Most importantly, is this interim solution safe?
Secondary to that, is the thermocouple the source of the problem as I was advised by AWC, or is the burner flame as I described it not in normal operation, in which case I can expect to burn out another thermocouple? (Meaning the thermocouple is doing it's job as intended 'cause the burner is running too hot.)
Does the flame engulfing the thermocouple, pilot and starter indicate that a gas pressure regulator needs to be replaced, or is that normal?