Kenmore 401.8505 Installation Instructions Manual page 5

NOTE: If you need to install ducts, note that the total duct
length of 31/4" x 10" rectangular or 6" diameter round duct
should not exceed 140 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 31/4" 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 31/2 '
x 10" rectangular or 6" diameter round duct should not
exceed 140 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.
EQUIVALENT EQUIVALENT
DUCT PIECES x NUMBER USED =
LENGTH LENGTH
Rectangular-to-Round 5 Ft. x ( ) : Ft.
Transition Adaptor S
Wall Cap 40 Ft. x ( ) : Ft.
90 ° Elbow 10 Ft. x ( ) : Ft.
45 ° Elbow 5 Ft. : Ft.
( )
X
Elbow 25 Ft. x ( ) : Ft.
90 °
Elbow 5 Ft. x ( ) : Ft.
45 °
Roof Cap 24 Ft. x ( ) : Ft.
1 Ft. x ( ) : Ft.
Straight Duct 6" Round
or
31A" x 10" Rectangular
Total Ductwork = Ft.
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.
Equivalent lengths of duct pieces are based on actual tests and reflect requirements for good venting
performance with any vent hood.
8505XAA 03807A-EN+MES.Jndb 5 2010-07-08 6:52:53