Best 437 Installation Guide

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MODEL 885BL WALL CAP
99040017F
MODEL 430 SHORT EAVE ELBOW
MODEL 431 LONG EAVE ELBOW
Mark and cut out a 10-1/
4” wide by 3-1/2” deep
opening in eave – at the
distance from the studs
shown for your model.
Insert discharge end of elbow (opening without the damper)
over the top of the plate and down into the opening. Fasten
discharge end of elbow to eave boards by nailing through the
elbow. Connect the fan housing to the eave elbow with 3-1/4”
by 10” duct. Fasten grille over eave end of elbow with the two
wood screws provided.
Caulk around grille. Tape all duct connections.
Cut a 10” round opening in the roof and extend the duct 3/4”
above the roof on the high side. Nail roof cap down through flange
on all sides (NOTE: If installed on a finished roof, insert upper
edge of flange beneath shingles.) Use roof cement to seal shingles
to top and sides of roof cap. Tape all duct connections.
NOT RECOMMENDED
FOR INSTALLATION ON
A FLAT ROOF.
MODEL 437
ROOF CAP
FRAME CONSTRUCTION: Use casing strips to space cap out flush
with finished siding. Nail through flange on cap and into casing
strips and sheathing. Connect fan to cap with 3” round duct. Tape
all duct connections. Caulk around flange.
Cut a 3-1/4” round opening in sheathing and insert cap.
BRICK CONSTRUCTION: Position cap so that it will be flush with
outer surface of brick. Nail in place through throat of cap. Connect
fan to cap with 3” round duct. Tape all duct connections. Caulk
around flange.
ACCESSORIES - 
INSTALLATION INSTRUCTIONS
ROOF CEMENT
(Seal shingles to
roof cap on sides
and top)
NAILS
(Seal all nail heads with roof cement)
RECOMMENDED FOR
HOODS OR FANS
OVER 150 CFM.