The airflow in your set up takes the path of least resistance from the damper to the chip loader hole, diagonally across part of the tray. That's why the mailbox with all air coming in through the door hinge or holes in the door, across the elevated
amnps so air goes under over the pellets to the 3" hole in the top rear of the mailbox. I plugged all corners and mounting holes in the bottom of the box except the two pencil holes closest to the door and I drilled a pencil sized hole between the two. I plugged the bottom grease drain hole and foiled over the hole in the bottom drip pan. All incoming air passes the pellets and the lit edge of the
amnps is right above the three holes. Plenty of air comes in at the hinge and each row has its own vent below with no holes in the door. I was going to add holes in the door if necessary but wasn't needed. I made a rack to elevate the
amnps. Some use binder clips on each corner or weld bolts for legs. All pellets burn to white ash no black pellets left behind.
View attachment 515205
View attachment 515206
View attachment 515207
This was before I drilled the middle hole in the bottom. I rarely use three rows of pellets so I screw a botlt from under the mailbox to plug the right side hole so more air at the two holes to the left. You can rotate the tray every 3-4 hours after the burn turns the corner so the lit pellets are towards the door and burn with the airflow, optional.
View attachment 515208
View attachment 515209