Harman P35i Insert Pellet Thumping randomly!?

[jasonwp]

I hope someone on here can steer me in the right direction. Unit is fairly new 4 years maybe 5 tons ran through. This year I have been noticing this said thump as seen/heard in attached video. It was thoroughly cleaned early this season and has only ran maybe 12 bags so far. The operation is fine just this random thump through the cycle. I have watched and there is no rhyme or reason at all when it occurs ie feed or combustion. When the stove is on the down cycle it does not do it only on the ramp up, mid and way down (running in auto mode). Before I start chasing my tail any ideas or suggestions? Really appreciate any and all help!

 

[Whitenuckler]

I hope someone on here can steer me in the right direction. Unit is fairly new 4 years maybe 5 tons ran through. This year I have been noticing this said thump as seen/heard in attached video. It was thoroughly cleaned early this season and has only ran maybe 12 bags so far. The operation is fine just this random thump through the cycle. I have watched and there is no rhyme or reason at all when it occurs ie feed or combustion. When the stove is on the down cycle it does not do it only on the ramp up, mid and way down (running in auto mode). Before I start chasing my tail any ideas or suggestions? Really appreciate any and all help!

My P43 makes some sounds like that. I was told not to worry, it's just the PelletPro gate inside where you clean the fines box. Sometimes it chops pellets in half. There is video on line if you search showing all the moving parts. It's not just the auger.

 

[jasonwp]

My P43 makes some sounds like that. I was told not to worry, it's just the PelletPro gate inside where you clean the fines box. Sometimes it chops pellets in half. There is video on line if you search showing all the moving parts. It's not just the auger.

Fines box? You talking about the metal guard that exposes the auger from the side and a usually a lot of pellets and dust reside after time? I always clean that out during major cleanings. I apologize I looked all over the place online trying to duplicate this sound and found nothing yet. If you have a link id love to see it. Thanks Sir!

 

[jackman]

My stove was making a thumping sound that was caused by a misalignment of the feed motor chain. Occasionally the chain would ride up on the sprocket and then drop back into place. From the sound in your video clip I don't think that's your cause but I thought I'd mention it anyway.

 

[Whitenuckler]

Fines box? You talking about the metal guard that exposes the auger from the side and a usually a lot of pellets and dust reside after time? I always clean that out during major cleanings. I apologize I looked all over the place online trying to duplicate this sound and found nothing yet. If you have a link id love to see it. Thanks Sir!

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I would clean that out during every normal cleaning if possible. On mine I can remove the control card and then it's easy.

 

[jasonwp]

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I would clean that out during every normal cleaning if possible. On mine I can remove the control card and then it's easy.

Yep that's what I thought you were talking about. I do the same. This year I even put some graphite powder in the auger to aid with dry lubrication.

 

[bogieb]

I heard pellets feeding just before the sound. Most likely a pellet being chopped by the slide plate assembly that is above the fines box. Or sometimes the auger itself will break a pellet that feeds in at a weird angle. (FYI, sometimes a small piece will get caught between the auger and the tube and screech its way down - LOL). (note that the picture is from my P43 so may not exactly match your stove)

It is also possible there is some small misalignment of the feeder pusher arm (2.9) and it is thumping back down (never had that happen, so don't really know).

 

[ARC]

Really good video on harman feed system. Another thing to check is that the bolt holding the auger motor to the auger is tight and lined up with the flat half of the motor shaft.

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[Whitenuckler]

Really good video on harman feed system. Another thing to check is that the bolt holding the auger motor to the auger is tight and lined up with the flat half of the motor shaft.

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Thanks for posting that. I had never seen it. Also very good as a back view of the stove. Mine is stuck in a corner and I can't see back there at all. I will have to pull it out to do any major work I guess. I have that one saved in my pellet stove info folder.

 

[jasonwp]

I heard pellets feeding just before the sound. Most likely a pellet being chopped by the slide plate assembly that is above the fines box. Or sometimes the auger itself will break a pellet that feeds in at a weird angle. (FYI, sometimes a small piece will get caught between the auger and the tube and screech its way down - LOL). (note that the picture is from my P43 so may not exactly match your stove)

View attachment 343738


It is also possible there is some small misalignment of the feeder pusher arm (2.9) and it is thumping back down (never had that happen, so don't really know).

I initially thought it was just pellet jams, but it will do it while the feed motor is off. It's very sporatic. Going to pull it out today and check everything. My unit is an insert so it's really hard to open things up and run tests.