When I light the heater...it will stay lit anywhere from 10 seconds to 24 hours. While the pilot light is lit...it appears strong...doesn't flicker. Then all of the sudden the flame will go out. The heater is about 6 years old, and has worked perfectly up until this year. I've tried to make sure any air has been bled out of the line, but it appears that maybe air is still getting in there.

Pool & Spa - Dyna Glo - "" Natural Gas Heater Mn200tba