I suppose you could use a bead of caulk on the top flange of the jack to seal with the cooler.
How to install evaporative cooler roof jack.
Installed swamp cooler on roof.
Set cooler in position on roof jack.
Cooler installation kit note.
The multi pitchtm roof jack serves only as an air distribution plenum and is not intended to support the cooler s full operating weight load.
Apron collar and flex duct not shown sheet metal slide in damper for winter use only large cover plate small cover plate barometric damper roof jack assembly rja 12 horizontal run level vertical rise roof.
Install a flexible duct from the roof duct to the ceiling register.
Use roof tar or waterproofing membrane to seal all openings.
Install the cooler duct a power wire and a thermostat wire leaving excess wire to allow a thermostat installation inside the home.
Install a duct transition piece if needed for a round flexible duct.
Select a leg kit that fits your cooler model and follow the cooler and leg kit installation instructions.
Install supporting leg kit.