Installation Guide
EQUIVALENT   NUMBER  EQUIVALENT
DUCT PIECES      LENGTH x    USED    =  LENGTH
   Rectangular-to-Round  5 Ft.  x (    )  =  Ft. 
   Transition Adaptor*
   Wall Cap  40 Ft.  x (    )  =  Ft.
   90° Elbow  10 Ft.  x (    )  =  Ft.
   45° Elbow  5 Ft.  x (    )  =  Ft.
   90° Elbow  25 Ft.  x (    )  =  Ft.
   45° Elbow  5 Ft.  x (    )  =  Ft.
   Roof Cap  24 Ft.  x (    )  =  Ft.
      Straight Duct 6” Round or  1 Ft.    x  ( )    =      Ft. 
      3¼” x 10” Rectangular 
   Total Ductwork =  Ft.
Equivalent lengths of duct pieces are based on actual tests 
and reflect requirements for good venting performance with 
any vent hood.
* IMPORTANT: If a rectangular-to-round transition 
adaptor is used, the bottom corners of the damper 
will have to be cut to fit, using the tin snips, in order to 
allow free movement of the damper
.
NOTE: If you need to install ducts, note that the total duct 
length of 3¼”x 10” rectangular or 6” diameter round duct 
should not exceed 120 equivalent feet. 
Outside ventilation requires a HOOD EXHAUST DUCT. Read 
the following carefully. 
NOTE: It is important that venting be installed using 
the most direct route and with as few elbows as possible. 
This ensures clear venting of exhaust and helps prevent 
blockages. Also, make sure dampers swing freely and 
nothing is blocking the ducts.
Exhaust connection: 
The hood exhaust has been designed to mate with a 
standard 3¼” x 10” rectangular duct.
If a round duct is required, a rectangular-to-round 
transition adaptor must be used. Do not use less than 
a 6” diameter duct.
Maximum duct length: 
For satisfactory air movement, the total duct length of 
3¼” x 10” rectangular or 6” diameter round duct should 
not exceed 120 equivalent feet. 
Elbows, transitions, wall and roof caps, etc., 
present additional resistance to airflow and are equivalent 
to a section of straight duct which is longer than their 
actual physical size. When calculating the total duct 
length, add the equivalent lengths of all transitions and 
adaptors plus the length of all straight duct sections. The 
chart below shows you how to calculate total equivalent 
ductwork length using the approximate feet of equivalent 
length of some typical ducts.
5
Installation Instructions










