ok so I purchased a Napoleon nps45 used over this past summer and can't seem to get the thing running right for the life of me. I'll start from the beginning. The first thing I did upon purchase was a thorough cleaning of the combustion blower, exhaust blower, exhaust vents and exhaust piping and quickly found out that the previous owner had never done any of this annual maintenance as it was complelty filthy. The exhaust blower was caked with soot, both exhaust channels in the stove (the one with the two doors below the burn pot) were complelty plugged as well as the find on the combustion blower were caked as well. I have cleaned all these parts approx 3 times since and have only burned about 1 ton of pellets this winter so far but can't get the stove to run efficiently, I can run it in heat setting 1 and 2 with no issues but when I turn it up to 3 on the colder nights after about 2 hours the glass will turn black and pellets will start to back up in the burn pot. I called my local dealer who suggested it may be my fuel and to buy some La Cretes and my problem should be solved but that solution did not work, I have been struggling with this thing for 3 months now to no avail and could use any suggestions as to what else I could be missing. Thank you in advance and please feel free with any questions I may have not answered.