If you set the barometric flap too lite, when you start to get a build up of fly ash in the pipe, the draft is reduced because the size of the pipe opening is reduced. Now, the baro will still open the same, because it's set too lite, and the draft to the stove will be reduced to near nothing. The secret is to draw from the stove, but not to much, leaving the heat in the steel body as long as possible. I have stated this before but it's worth repeating. When sweat is visible on the bottom side of the hopper lid, you will soon have a draft problem. The heat and gases inside the stove can no longer be drawn up the pipe, so they need a way to get out of the stove. The feeder or hopper will work just fine for gases to escape, but not what we want. This can be caused by a faulty baro, or faulty setting. With a LL we recommand 2/3 on the weight.