I have this problem as well with my 19. The water heater has been glitchy since we brought it home. Sometimes it fires right up and stays lit, but more often it takes many attempts. The gas builds up, there is a POW when the igniter lights, it runs for maybe 20 seconds, then flames out. Thinking the line was clogged with dead bugs or something like that, I tried to blow it out, and that did seem to help. You might try it before taking anything apart. At this point, I can usually get it to stay lit after multiple attempts, but it does take multiple attempts most of the time. I'm planning a trip to Chilliwack this summer before it goes off warranty and will ask them to check it out. In the meantime if anyone has any suggestions, I'd be interested in hearing about them too. Thanks!