On A Roll, P43 Acting Up Again

Muffler?

There is a tube in those units that was nicknamed the muffler I believe it is part of the gummy stove fix.

Crossover tube?

That is likely it, but I don't follow those finicky stove's proper part names I like the nicknames better like gummy stove, muffler, burn pot bubbles (in the trade this is known as creep failure), flapper, etc ...

Another thought...Does your model Harman have a strip of steel that sits on the air wash channel beneath the window? It is installed correctly?

the precursor to the hopper lid pin switch....the muffler itself was connected via air tube to the vac sensor to interupt the auger when the hopper lid was opened...a sort of short lived set up, replaced by classic pin switch mounted under hopper lid...muffler sometimes get plugged with ultra fine sawdust and then does not sense the vac pressure of the hopper, and then it no feed pellets..

Maybe the tech didn't change the dip switch settings on the control board? Did he hook up the Harman DDM tool or do a draft reading?

I had this same issue one time only about a month ago when I did my full tare down up to the elbows in soot one ton cleaning. When I realized the pellets were falling into the ash pan nu-burned I quickly put the stove to manual and shut it off until the flame burned the full burn pot of pellets then turned it back on issue went away. This was the only issue I have had and never found root cause. Interesting to find out

So, I have tried different feed rates, going all the way down to a 1, which had made no difference, other than making for a sad amount of heat after it gets going. On Tuesday, I switched pellet brands. Guess what? Problem is gone. I am quite confused, but I guess it just proves again, cheaper is not always better. I have burned the same pellets on and off all winter. I still think there is some underlying issue. The repair guy is planning to come back out next week. I guess I will have to try the pellets that caused this issue again. I am also finally adding my OAK this afternoon I hope. Curious to see if that has any effect.