My dad installed about three years ago a Hampton GC60 pellet stove. It is mounted in the central living room of a ranch house. The exhaust is vented horizontally through the back of the stove and out the side of the house. The stove was purchased brand new and installed professionally. Short story: the system is leaking smoke into the house, and has been basically since the word go. The installers came back out and put a pipe extension outside. That did not help. They came back out, and quite literally gooped up the exhaust pipe with a ton of caulk. Still, she leaks smoke. Then they came back out and recommended a fresh air exchange. That was installed, and verily, the smoke continues to leak. Then it was suggested that my dad was burning less than ideal pellets (Lignetics), so he switched to premium hardwood pellets (Hamer's). And indeed, she smoketh still. My dad keeps the stove super clean, but if you run your hand down his walls, they will come away with a skim of black soot. It ain't good. Now, a new fella has come out, and said that the stove pipe needs to be mounted up (to be clear, it can be mounted horizontally out of the house, but then needs an elbow and long vertical pipe). He claims that the fresh air exchange cannot be mounted right next to the end of the exhaust pipe. He has quoted my dad a price, but the frustration level is sufficiently high that my dad doesn't think the new length of vertical pipe will solve the problem. At this point, he wants the stove out of his house. Before he does that, I wanted to offer this conundrum up to a crowd sourced solution of folks who know pellet stoves. I am a woodstove insert guy, so this is not my territory. Thanks in advance.