Yep, confused, because I am not quite sure what you are saying.
Listing: Listed to ULC S609, ULC/ORD C441 and UL 641
The listing for a PL vent is the same for Ul641 as is for your ULC S609
Bottom line is, if I see a vent on a pellet stove on an Inspection, I will question it and have requested that it be inspected by a licensed professional for that installation.
To many variations on the installation due to multiple manufacturers and their dictated installation requirements.
Marcel 
