Installation Guidelines

Install Types

Damper must be installed square.
Damper is manufactured ½” (12.7 mm) smaller than specified duct size.
Ensure that duct is square and/or large enough to allow damper to be installed square.
Make hole in duct work, if required, to allow extension of drive rod.
Bottom of frame must sit flat on floor of duct to prevent twisting, sagging, or bowing, as this could cause leakage between bottom frame and bottom blade.
Verify that damper is square and then secure bottom frame to floor of duct using a 90° mounting angle. Operate damper manually to confirm proper blade sealing.
As each mounting angle is installed, verify operation to ensure damper blades are sealing correctly.
Caulk all connections/joints between damper frame and duct to minimize installation leakage.

Damper must be installed square.
Front and rear damper flanges are 1” (25.4 mm) larger than duct or opening, around entire perimeter.
Damper is manufactured so that finished O.D. is 2” (50.8 mm) greater than opening width and height dimensions.
Do not assume that duct is square. Verify that duct flange is square, flat and even.
Verify that damper is square. Operate damper manually to verify free movement of blades and correct sealing.
Fasten damper to duct. Re-verify that damper is square.
Repeat procedure for other flange, if ducted on both sides.
Caulk all connections/joints between damper frame and duct to minimize installation leakage.

Damper must be installed square.
Rear damper flange is 2” (50.8 mm) larger than duct or opening, around entire perimeter, providing a larger fastening surface.
Front damper flange is 1” (25.4 mm) larger than duct or opening, around entire perimeter. (Note that Extended Rear Flange Install Type dampers are not designed so that the front of the damper may be inserted into an opening, as the side frame members extend to the full height of the rear flange.)
Damper is manufactured so that finished O.D. is 4” (101.6 mm) greater than opening width and height dimensions.
Do not assume that opening is square. Verify that opening or duct flange is square, flat and even.
Verify that damper is square. Operate damper manuallly to verify free movement of blades and correct sealing.
Fasten damper to opening surface or duct. Re-verify that damper is square.
Repeat procedure for other flange, if ducted on both sides.
Caulk all connections/joints between damper frame and opening or duct to minimize installation leakage.