Bakers Pride Y600 Won't Always Stay Lit

One of my Y600s (double stack) does not always stay lit. Some days it will run fine all day, while other days it needs to be re-lit a number of times. The thermopile is fairly new, and although is not bright red, generates around 200 millivolts consistently, and the pilot flame is decent size, but not quite as big as the pilot flame on the other Y600. I haven't been too concerned about the pilot flame size though since the thermopile seems to be generating enough millivolts.

I have a new...

Bakers Pride Y600 Won't Always Stay Lit