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TAMCO Installation Guidelines for medium-duty backdraft dampers

Install Types

In Duct Install Type


  • Verify that backdraft damper is square.
  • Backdraft damper is manufactured so that finished O.D. is ¼” (6.4 mm) maller than opening width and height dimensions.
  • Ensure that duct is square and/or large enough to allow backdraft damper to be installed square.
  • Insert entire backdraft damper into opening. Bottom of damper frame must sit flat on floor of duct to prevent twisting, sagging, or bowing.
  • Install single-section units using mounting clips or angles. Arrange clips (angles) snugly against the perimeters of the front and back damper frames, securing clips (angles) to duct work (TAMCO recommends that the clips (angles) should be fastened to the duct work only and not to the backdraft damper. This will prevent the fasteners from binding or twisting the damper.)
  • If access to both sides of the backdraft damper is limited, install clips (angles) to the duct work around the perimeter of either the front or the back frames. Then secure the clips (angles) to the damper frame.
  • TAMCO recommends that a minimum of two fasteners per frame length be used (top, bottom, left and right). Fasteners should be spaced at 12” (305 mm) to 15” (381 mm) oc.
  • Caulk all connections/joints between damper frame and duct to minimize installation leakage.

Front or Rear Flange Install Types


  • Verify that backdraft damper is square.
  • Inserted portion of backdraft damper is approximately ¼” (6.4 mm) smaller than specified duct size.
  • Ensure that the substrate the backdraft damper will be attached to is flat and level.
  • Pre-drill fastener holes in the backdraft damper flange, before placing over opening, to reduce twisting and binding.
  • Place single-section units directly on wall or floor. Secure backdraft damper's flange to substrate using appropriate fasteners.
  • TAMCO recommends that a minimum of two fasteners per frame length be used (top, bottom, left and right). Fasteners should be spaced at 12” (305 mm) to 15” (381 mm) oc.
  • Do not overtighten fasteners to substrate. Doing so may damage or twist the backdraft damper, which will increase air leakage.
  • Caulk all connections/joints between damper frame and duct to minimize installation leakage.

Documents:


TAMCO Medium-Duty Backdraft Damper Installation Guidelines