6' ducting on island hoods converting to larger?
I'm looking at a few different hoods for a peninsula. Trying to stay under $1,500.
There are some we like from Faber, Zepher, and XO but they are all 6" ducts...
My understanding was if the spec says 6", you are stuck with 6". You can run an 8" adapter pipe to the roof after it leaves the hood but your 6" on the hood is a bottleneck. Then, while looking at the faber website I saw this in the FAQ:
"Faber hoods should be ducted using ridged smooth metal ductwork. See the installation instructions for specific guidelines, but in general most hoods use 6 inch round ducting. The basic rule of thumb for ducting, is keep it short and straight! The shorter the duct run the better, and the less elbows in the duct run the better. Generally 35 feet is the maximum duct run, adding 5 feet for every elbow used. Never use two elbows back to back in a duct run, and seal all joints with duct tape. Also, reducing the size of the duct is never recommended, you can however over size the duct to have less pressure. For example if the hood uses 6" round ducting, you can convert to an 8" round duct. "
My question is this: If you "convert", is it a separate piece that you buy to get rid of any 6" duct or is it just an adapter somewhere above the ceiling that connects your 6" hood to an 8" system?
We are looking at running a 600+CFM system. We rarely run more than one burner at a time.