I have a Laing 303 and have it installed exactly as specified. Yes, they do seem very concerned about keeping air out of the pump. I figure they make the unit, and they should know how it should be installed. I don't know where you get the idea you need some kind of "air scoop" and what purpose it would serve. The auto vent valve just bleeds small amount of air out of the line as needed. The hose bib is for major system bleeding after the lines have been drained for some reason. You are not drawing air into the system, and the tiny amounts that bleed automatically are not even noticed. Just go by the installation diagram.