Drolet Eco-45 Lazy Flame , Heavy Sooting, Burnpot overfills

Hi, I've had this pellet stove for about 8 years. Recently we changed to a different pellet supplier as Rona no longer wished to carry pellets. Since then I have had black soot, clinkers and now the stove is acting up. Before that we were using Premium White Pine pellets and were the nicest burning pellets we had ever had in this stove.
I cleaned the whole exhaust venting, fan blades and the port for the pressure switch, so I do not believe that is the problem. I either have an obstructed intake or the top of the stove where the tubes are is obstructed.
I also checked the intake electric fans and they seem to be working fine. The blower fan was changed a couple of years ago and the new one has ball bearings in it instead of bushings.
I have a lazy flame and when I start the stove it puffs smoke out around the glass and door sometimes. I have to turn the intake vent almost closed to stop it. The burn pot fills up in 4-5 hours and I have to shut it down and clean it out.
I came across a posting back in 2009 on another site where a guy was having the same problem, but I could not find where it was resolved.
Does anyone know what is causing this?

Well, here's an update of what I found. The top of the stove above the tubes was pretty much full of ash. I used a piece of aluminum to get between the tubes and scrape it off and now it is working like it should. Maybe better than I remember as we bought the stove used. A lot of ash came off as there looks to be about an inch above the tubes that was full.
For anyone with one of these stove, I've found that softwood burns the best in the Eco-45. Especially White pine and spruce pellets. The white pine pellets we were burning were from Canadian Tire.