Heatilator ECO-ADV-PS35 - pellet build up in pot

[WarmIthacaHose]

we've got an older Heatilator which has been a workhorse. Lately, though, the pellets don't seem to be burning quickly enough, and within 6-8 hours, they are overflowing the burn pot, despite the low delivery rate of pellets. We've tried removing ash from the pipes, yes the ignition light works, grid at bottom of the pot is not clogged... ??? Suggestions?

 

[jzm2cc]

Assuming you have cleaned behind the 3 removable panels on internal back wall of firebox and pipes and nozzle are clean.

Have you reduced pellet feed by sliding restrictor downward a bit in hopper?

Is firepot bottom gap relative to firepot no more than a dime's thickness? If gap gets too large air will bypass the normal burnpot holes. One bolt controls this gap.

Could be fly ash build up on exhaust blades also.