I have a A. O. Smith Promax natural gas water heater, model GCV 40 100. It's dated 4/30/07 but we have only live here since 2011. About 9-12 months ago we started noticing the pilot light wouldn't stay lit. first this only happened maybe 1-2 times a week but has now progressed to up to 8-10 times in a single day. It doesn't happen everyday, it may stay lit for days at a time but other days its a battle to get it to stay lit long enough to take a shower. Any suggestions?