I had a lot of puffing at first as well. I believe that my change in habits to more slowly reduce the air and to keep the air open a crack, especially when it is warmer out (lower draft days), has pretty much eliminated them for me. Mind you I never had any really violent ones like I've heard described here (i.e. never heard them out of the room or had pipes rattle etc). I tried to run the PH like I did the FV at first - that was a mistake. While the PH is very forgiving/adjustable on the air settings, I don't think I can just 'heat it up and slam it down to where I want it after engaging the cat' like I did with the FV. I have found that engaging the cat, then waiting a few minutes before reducing the air about 1/2 way to final destination, then wait a few more minutes and then moving it down again to final setting works much better. I almost always run with the air fully closed with the PH which is weird in a way - I 'set the burn temp' by letting it run up hotter before closing the air down fully. Where I get caught doing this during the day if the temps rise significantly and I'm trying to run very low temps - then I have to remember to not shut the air all the way.