Harmon P68 auger vibration?

[cmh2007]

I have a year old Harmon P68 pellet stove. The stove is excellent except for a low frequency, but very loud vibration that increases in volume toward the end of the auger cycle. When I say loud, I mean I can hear it above the blowers and on the other side of the house with doors closed. I had the dealer come out and unfortunately, I already knew more about the stove than he did. I have pulled the auger motor and run it separately. It is very quiet. I have pulled the auger and re-aligned it....it too is very quiet when turned by hand. However the two running together creates a vibration I cannot track down. Help please! I'm to the point of selling a very expensive stove unless I can fix it. Thanks

 

[wilbilt]

My old stove will build a resonating noise under certain conditions. It can approach the effected experience of an F-18 on full afterburner.

There is a low rumbling that gradually builds in the lower frequencies, and then the sheet metal panels start vibrating. It comes and goes.

I attribute this to various factors...

It is an old stove, and probably due for some long-overdue maintenance, If I can ever find a manual for it.

I have a "manufactured" home, and the floor is not very solid. It is actually a pretty effective passive sonic resonator.

Due to twiddling with the (limited) adjustments available, I might be over-firing my pellet stove.

I do occasionally hear a strange noise during the auger cycle. My auger cycles about once every ten seconds, with the cycle time dependent on the heat setting.
Once in awhile I hear a metallic "choink" at the end of the cycle. I have assumed this is due to the auger breaking a long pellet.

 

[cmh2007]

Nobody has any experience with a Harmon stove making these sounds?