Harman P-61 feeder problem

[grandfanda]

I'm having a problem with my Harman P-61. Pellets feed normally through the auger until we get a nice burning full-blown flame. Then, for reasons I hope forum users will recognize, the pellets stop feeding until the flame backs down all the way back to the auger. During this dieback, the feed motor light comes on regularly but the motor itself does not. The status light stays on constant, not blinking to show there is an error somewhere. Once the flame gets all the way back to the auger, the feed motor starts working and builds up a nice flame and the cycle starts over. I'm suspecting that it's a draft problem, but the Harman website only has manuals for the P-61A, which has a set screw on the control board to adjust draft. The P-61 does not.
The gaskets on both the glass door and the hopper lid seem to be fine. Does anybody have a suggestion?
Thanks!

 

[summit]

first thing is first: check the system for cleanliness, check the air intake flapper to make sure it is not stuck, check the pipes. 2nd, verify the exhaust fan is not stopping. 3rd, check the fines cleanout area on the feeder, a pile of sawdust can jam up the feeder and keep the motor from making full revolutions and keep the slider from letting the proper amount of fuel into the feeder. Check the feedser itself to make sure no foreign objects are stuck... If all checks out then it probably is a mechanical problem... most likely culprits would be the differential switch or the feeder motor itself. Lastly the ESP probe, but if that was faulting you'd probably see a status light, and the feeder light would not be coming on.