Andy H said:
and you're 100% sure those two top vents are cleaned? if you have burned more than 5 or 6 bags of pellets and have not cleaned them out then they are dirty. you can't see if they are dirty but when the stove is cool stick your finger up there, you'll feel the build up. the best way i've found to clean them is to stick the pointy adapter thing from vacuum right in there and suck all the ash out.
I'm assuming your speaking of the 2 openings in the feed tube you mentioned before.
To be honest, I couldn't see them then and just looked again with a mirror and flashlight.
What I see is an opening for the auger only and it's clear.
I have a 3/4 vacuum hose that runs through a water tank (my old drywall dust vacuum).
I run this up the tube each time I clean the stove as well as the ignitor and that lower vent hole.
I really doubt I have blockage...