Cascade Series Install Manual
page 9 of 16
INSTALLATION: FAN & DUCT
NOTES: 
•   The fan assembly must be soundly supported by attachment to structurally sound framing. Provide
   additional framing with minimum 2-by-4 lumber as needed for fan support.
•   Each fan assembly should be positioned with at least 24” of free space in front of the fan, for air to be freely 
   blown into the attic by the fan.
•   Position the fan with a slight upward angle and in a direction minimizing disturbance to attic insulation.
•   The acoustical duct should be installed with a gentle bend of close to 90 degrees, from vertical to nearly
   horizontal, to minimize fan sound inside the living space. It must not be kinked or bent sharply, especially 
   where leading into the fan.
•   The acoustical duct must be installed with the air  ow direction arrow (as marked on the duct) pointing 
   downstream (towards the fan).
1.  Lay the fan assembly on top of the ceiling joists,
   within a few feet of the damper assembly and
   and underneath the area where the fan will be
   suspended in place.
2.   Rotate and brace the fan assembly so that the 
 electrical handy-box on the fan is in the 12-o’clock 
   position (on the top of the fan). This is important to 
   avoid twisting the duct, while having the fan’s 
   electrical handy-box within the 10- to 2-o’clock 
   position once installed.
3.   Adjust the  exible duct collar on the upstream end 
   of the duct to be as loose as possible. Squeeze 
   and position the  exible acoustic duct collar over 
   the oval-shaped collar on the damper box, and attach 
   using 3 of the screws provided, or other suitable 
   screws. Note that twisting the duct will cause the 
   fan to try to roll out of position. Seal the joint with 
   approved duct tape, mastic, or other approved means.  
4.   Lift and support the fan assembly into position beneath the rafters, truss structure or other framing to be 
   used to support the fan, with the electrical handy box at approximately the twelve-o-clock position.
   Attach both ends of the metal fan support strap to the framing using a minimum of two screws for each 
   end of the strap. 1” drywall screws and large washers are supplied; other fasteners of appropriate 
   strength may also be used. 
5.   Using the black woven poly strapping, support the acoustic  ex duct by attaching the strapping to
 attic fram
ing as shown. Fold each end over a large washer 2-3 times and fasten to the framing by driving 
   the supplied 1” drywall screws or other appropriate fasteners through the washer and into the framing. 
   The strapping may be cut to length with ordinary scissors if desired.
6.   Repeat steps 1-5 for the second fan assembly. The fans should be facing opposite directions.
7.   Replace the insulation around and over the damper assembly. Additional insulation may be added to
   further reduce heat transfer and fan noised from the attic to the living space.
FIGURE 3: FAN & DUCT STRAPS DETAIL
P/N 780105002 01/21 Rev A










