We have been using our new Lopi Leyden for two months and have been through about 1.5 tons of pellets so far. In the last few days the pellets have been overflowing the burn pot every day. The glass is getting black faster and soot is building up in the burn pot. I removed the brick panels and everything for a thorough cleaning but it still does not seem to be burning efficiently. By the way, the air (outside) has been wide open while we have had this problem. Temp has mostly been set on 3 or 4. Any ideas?