I bought my house 3 years ago and have yet to have a successful burning season with the small CDW federal airtight that came with house. Since I have been using it, it seems to favor the side vent. This past week when I have the vent open, smoke begins to leak out of areas that aren’t sealed like the corners. And the top of the front door. It seems as though all of a sudden my stove is not getting a good draft. The wood just smolders and smokes. The stove rear vents to the wall where it goes to a clay lined chimney. Chimney sweeper said it’s a great chimney with no issues. I tried opening a window with no change.