hoping someone can give some advice on a duct run that I have. It is about an 8" or so flexible duct that comes off of my plenum (?) and it has to make a fairly long run (about 30+') to the back part of my house to the family room. It makes it's way upstairs to the attic then comes down to the family room ceiling. Due to the space limitations, I cannot run a bigger diamater. Immediately after it comes out of the plenum it goes up over & rests on a rafter that kind of constrict/compresses the duct some as it makes it's way to the family room. It also has a few (roughly) 90 degree bends. I am thinking of trying to reroute it so that it does not go over this rafter and try to eliminate some of the bends or at least make them less sharp. My hope is that I can get more pressure blowing out of this duct. It blows a lot less pressure than the rest of the ducts.
Any thoughts/advice would be appreciated.