Recently purchased a 1991 NC-6 stove. Installed it into outside masonry chimney. Made a fire with the draft handle all the way out and lit the kindling. Added wood and then closed the door with the draft still open. As soon as the door was closed the flames diminished. They didn't go out but diminished. I put the draft part way in and it was going to put the fire out. The chimney and piping is clean. I don't have a manual for the stove so I don't know if something could be blocked. There was thread on your site that mentioned a mineral wool filter that was taken out and it helped with the draft. Any help would be appreciated. I contacted the firm that makes the current country flame stoves and the said that they had no info that it was the firm in Missouri that made the NC-6. They are out of business