lennox profile 20 combustion trim

[coachmen98]

I have a profile 20 and I am trying to adjust the board so the cumbustion fan will burn the pellets completeley
The damper is fully open allowing the maximum cumbustion air
I tried lowereing the fuel feed rate and still the ash pan fills up and the stove goes default after 8 - 10 hours.
The push button on my board is set to only adjust the auger motor
Do I need to jumper from Com to combustion to get the combustion trim to work???

Teh owners manual says call the Techs at Lennox

Any help would be appreciated

Jim