first came to my attention when unspent pellets or not fully burned pellets were found dropping from the burn pot into the ashbin...

corrected the problem by pulling unit out a bit so that airintake was not exclusively from the outside but also drawing air from inside of the house...

did not like the idea of drawing air/oxygen from inside so i pulled unit out totally to get to the feltlike fabric within the exchange box...

since the felt appeared clogged with soot, the air compressor was used to blow the fabric clean...

reassembled and made sure intake hose fit right up into unit...

everything seemed fine until i used aluminum foil tape to ensure seal around pipe was airtight....

this was not the thing to do because i was back to square one - this caused the fire to starve...

took tape off and enough oxygen seemed to be leaking into unit from room as the pellets are fully consumed by flame...

would like to get some input before i contact harman dealer to determine whether felt fiber filter needs replacement or are we needing to measure/calibrate draught...

thanks in advance for your input....

windr