I have a similar problem and you might be able to help me.
I own a boiler okofen pellematic smart and it is constantly defective "smoke wind", I found in the home full of pellets not burned, soot etc.
I soon thought that the ducts were obstructed but I did not find anything, the fan seems to work properly ..
It seems that there is a draw problem (big white smoke, muffled fire).
It started during the first cold weather of this winter and since impossible to make it work so much to tell you that it is urgent: /
Thank you in advance for your answers
We had traded elsewhere, I think.
At what level do you see "big white smoke" ????
Because precisely, with condensation, leaving the duct on the roof, there is not much steam to condense and plume, at home, is barely seen (on the roof) ...
It reminds me of pellets that have taken moisture.
I suggest you do a check as follows:
a) weigh a layer of 1 / 2 cm pellets in an open dish in the microwave; to note
b) micro-onder 1 mn, redo the weighing; Normally, it's lighter because water has been evaporated
c) stir the pellets a bit, start again; reweigh
etc etc as long as the weight goes down ... Stop when it does not go down or the pellets start to brown ...
Warning: always stay close, it can catch fire !!!!
You should have max 8% humidity (legally, max 10%): weight of the water (the difference between the first and the last weighing) / final weight (supposed to be the dry weight)