Went to Harman's website to download the Advance model manual as I am replacing the ignitor. However, I saw in the back of the manual a new mechanism for feeding the pellets. One that doesn't have the chain. The older design is a quite noisy. I would think this direct driven design would be quieter, no? Would it be possible/practical to change out the mechanism on an older Harman Advance model (pre Serial Number 008360001 Feeder Assembly) to the newer design (Post Serial Number 008360001 Feeder Assembly)?