I have a Pinnacle PB150 in series with my oil furnace. I recently had a problem with the PB150 producing creosote which actually ended up in a small chimney fire. I had a chimney sweep come inspect it and he recommended replacing a small section of the chimney pipe and also to clean the heck out of the PB150; I found that the exhaust fan was pretty dirty but now it looks factory fresh along with the rest of the unit. I also installed a clean air intake in hopes it would help the unit burn better. After cleaning the unit, installing the new chimney section and re-sealing everything I fired it back up yesterday. Already I can see the glass on the front building up with black soot, which never happened last year. Some other info about my installation, I have >10 feet of vertical stack on the outside of my house terminated horizontally because it is below the roof-line and the rest of the chimney consists of a 1 foot vertical rise out of the PB150 followed by a 3 foot horizontal run through the wall. I burned Lignetics last year and decided to try Rocky Mountain Pellet Co. Pellets this year based on good reviews. I am really at a loss on how to get this thing to burn better especially since I installed the clean air. Also, I even run it with the draft slider all the way open and the draft fan on the high setting. Has anyone had similar problems and if so how did you fix it?