Sounds like a draft issue the easiest way to fix it is install a drafting vent on the roof most of them are round balls that sit ontop of the chimney and spin...
Thanks for the input.
Researching further it seems this particular stove is know for "back-puffing". That describes what I'm seeing perfectly and even though the manufacturer says otherwise, it seems to be a design issue. The one remedy I've read is drilling some holes in certain places of the manifold. I'll keep looking.
Check the chimney cap screen, they get clogged easily with suit
building a good chimney with a good draw is a lost art. 75 years ago + it was the most criticaly important and expensive part of building a new home, esp in cold climes. make sure the chimney is clean and has no leaks first. a spinner will improve draft, or maybe increase the height from the roof if it's a modern round steel tube type. doing a Bubba to the stove would be a last resort. is the stove an airtight? make/mdl? I got that chimney fire line from a fireman who had to come to my house twice to finaly put my chimney fire out.
