Ok so I am having trouble with my duct/pipe sizing. I select the duct that I want (ok system where all the diffusers have the right cfm assigned to them and the VAV box reads the proper total cfm and my system anaylsis tool works ok.) and I select equal friction method, and calculated size only for branch sizing. I hit ok, and the duct seems to be only square or just plane wrong. like for example on one branch it is 7x7 on the other it is 6x6 and on the thrid branch it is 4 3/4" x 4 3/4" and my ductulator says the proper size for .01inwg for 180 cfm (branch cfm) should be a 6x7" duct. what gives? Why is it always square? And why when I use the system inspector is there no pressure loss? The static pressure shows up but not the pressure loss? Thanks!
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