On the advice of many, I decided that once a week I should shut down completely, cool off, and do a good cleaning. Today I did this. While cleaning the burnpot, I scooped out all material from it, and found that there were some hard deposits on it, on the surface that curves out of sight. But I could feel them, and although it took a screw driver, I got them all off. They must have been clogging some of the air holes. Now the stove is running very, very well - beautiful flame, and the warmest stream of air out the front that I have felt in a while (this is on Stove 7, feed rate max). I know I am getting efficient burning and high capacity. The dealer told me that deposits could feel like steel but they had to be removed - I saw that, and will make sure I clean this well every week.