PDA

View Full Version : Duct sizing



Clint Olver
06-26-2011, 10:41 PM
5hp 15" impeller Pentz Cyclone.

8" main branch to 6" for each machine, or all 6"?

C

David Kumm
06-26-2011, 11:19 PM
It depends on the length of the runs, number of bends, drops etc. I run a 5 hp 15+ impeller with up to 50 ft runs and go 8 to 7 to 6. I would not go to 6' mains until the last drop or two to reduce static pressure. Dave

Alan Schaffter
06-27-2011, 1:44 AM
Draw the best run duct layout possible with minimal bends, especially 90's then run the numbers (go to Pentz site). What is the size of your blower intake? I suspect you will meet the CFM requirements of your machines and meet velocity requirements with 6" duct. If not got with larger. Unless you will be using more than one machine at a time, or your runs are so long that your velocity drops below 4000 fpm, I would maintain one size all the way to the machine without stepping down. That way you can use thin wall PVC (ASTM 2729) and save a little money. If money is no object and you like running metal duct then go for it.

I have Pentz 3D cyclone, 3hp motor, 14" impeller, and longest run of 28' but it is very well laid out. I use 6" PVC all the way to the machines.