John ,I would still read your warranty ,some times installers ,are not the sharpest ,knifes in the drawer when it comes to warranty and exclusions of same .
I still find it hard to believe that they will cover this use ,fine saw dust is a completely different breed of cat than house dust and hair ,plus the volume of stuff that cakes as part of it's nature ,I think will overwelm the unit , I hope I am wrong ,and you have great success and no issues ! If ,I am wrong ,I can see a lot of people converting to what you have ! best of luck and keep us posted !