Harman PC45 issues

We have a PC45 at our office that recently has been having problems. The flame has been burning extremely lazy the last few days, and burning dirty. We did a thorough cleaning of pipes and unit but it still doesn't seem right.

Just yesterday I found the entire fire box engulfed in flames due all the unburnt pellets being pushed into the ash bin, and black smoke pouring out the exhaust.

After a few hours of running the entire burn pot will be filled about 3 or 4 inches high and pushing partially burned and hot pellets into the bin.

The flame actually looks better with the hopped lid open. There is no OAK installed. And the flapper is freely moving, but seems to stay closed even with unit on

Pics of pipe setup, just goes out horizontel thru the wall about 2'.

Any ideas?

The pic is just after i scrapped the 2" of crusty ash and most the unburnt pellets off

We cleaned it a few days ago, seemed ok

Feed is at 4

Also, it fills up to the top of those side rails on the burn pot, 2" of crust then 2" of partially burned pellets

Good question, will check on next down time

We thought about that, did the dollar test on both doors. Top needed to be tightened, dollar good there. Then the bottom door was loose, new gasket, dollar test solid.

Pic is about 5 hours of burn time, glass heavily sooted, fire lazy and deep orange. Pile of large embers forming. Just doesn't seem to be pulling air in, flapper should be movin right? Or at least open...

Yep, no change. Video comin, it just flashed over again

This ended up being of all things the hopper extension. We took it off, closed the main lid and it's been burning just fine ever since. Those three ez-locks on the extension weren't pulling tight enough. Didn't look at them anymore so i'm not sure if they can be adjusted, will check tomm.