I spoke with a dealer for the Jotul c350 fireplace insert, that I am planning to buy, yesterday and question his advise. I was asking about where the stainless liner passes through the old damper. My damper is only 5 inches wide and the tube is six, plus, I believe that the area is supposed to be sealed around the pipe. He said that they always just smoosh the pipe to an oval, pass it through and count on the seal at the top of the chimney. It sounds bogus (he seemed like the type to just wing it). I was also wondering if combustion air on these types of stoves ever comes from the chimney vs. the room? Thanks for your help, I want my install to be correct (I won't be going back to that guy) whether I do it myself or hire it out,