Originally Posted by swampjeep
so I'm guessign the 7 3/4 ft is for flex type, then these other charts are for rigid type?
Thanks. I went through all this in the manuals. My vent run resembles the bottom exhaust installation in the first diagram, with one exception - once it is under the floor (pictured) it makes a 90 to the right and runs across the crawl space to outside...maybe about 4 - 4 1/2 feet. So...the whole run is probably 6-7 feet total with 3 90s.