I'm looking for advice on what to do about a heatilator a36c that was installed in my new built house. Everytime we've had a fire so far, some smoke makes its way in through the top vents. It gets so bad we had to open windows and leave the living room. It seems to get better as the wood burns and smokes less but the first 30-45 minutes are rough. Surely this isn't normal right? The picture doesn't show the smoke but shows were the smoke comes from. What can I do to fix this? Any help would be great, thanks!