1) If my roof cap has a built-in damper, do I need the flap in the Duct Connector?
2) Assuming that I do need the flap, then more help in installing the flap would be nice. Here is where I am confused:
Looking through the 6 inch round connector as it goes into the rectangular shape to attach to the fan, the top of the rectangle has a "foam strip" glued to it. If I insert the flap with its top in front of the foam, then the flap will be restricted from fully opening, but the flap will close completely (see picture "flap top in front ..."). If I insert the flap with its top behind the foam, then the flap won't close, but can open fully (see picture "flap top behind..."). Please let me know which is the correct installation.
It seems to me that the "foam strip" should be positioned more towards the front, so that the top of the flap can be behind it, which would allow the flap to both fully open and close.
There are no details given on this part of the installation. I feel that this is important information, because the tabs on the flap seem weak and will only tolerate so many attempts at installing it correctly. Also, I believe that I have the orientation of both parts correct, but it would be nice to have confirmation.