Beko 24 Inch Built-In Microwave Installation Instructions - Manual (Page 5)

If you need to install ducts, note that the total duct length
of 3 1 /
4
" x 10" (8.3 x 25.4 cm) rectangular or 6" (15.2 cm)
diameter round duct should not exceed 140 equivalent
feet (42.7 m).
Outside ventilation requires a HOOD EXHAUST DUCT.
Read the following carefully.
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 connect with a
standard 3 1 / 4 " x 10" (8.3 x 25.4 cm) rectangular duct.
If a round duct is required, a rectangular-to-round transiting
adapter must be used. Do not use less than a 6" (15.2 cm)
diameter duct.
MAXIMUM DUCT LENGTH
For satisfactory air movement, the total duct length of
3 1 / 4 " x 10" (8.3 x 25.4 cm) rectangular or 6" (15.2 cm)
diameter round duct should not exceed 140 equivalent feet.
ELBOWS, TRANSITIONS, WALL AND ROOF
CAPS, ETC.
Elbows, adapters, wall and roof caps, etc. present additional
resistance to air flow and are equivalent to a section of
straight duct which is longer than their actual physical size.
When calculating the total length, add the equivalent lengths
of all transitions and adapters plus the length of all straight
duct sections. The chart on the right shows the approximate
measurement of equivalent length of some typical ductwork
parts.
Use the values in the chart for calculating total ductwork,
which should be less than 140 equivalent feet (42.7 m).
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 adapter is
used, cut the corners of the damper with tin snips to allow
free movement of the damper.
DUCT PIECES
EQUIVALENT
LENGTH X
NUMBER USED
EQUIVALENT
LENGTH
EXAMPLE ONLY (VALUES)
Rectangular-to-Round
Transition Adapter
5 ft (1.5 m)
x 1
5 ft
(1.5 m)
Wall Cap
40 ft (12.19 m)
x 1
40 ft
(12.19 m)
90˚ Elbow
10 ft (3 m)
x 1
10 ft
(3 m)
45° Elbow
5 ft (1.5 m)
x 1
5 ft
(1.5 m)
90° Elbow
25 ft (7.6 m)
x 1
25 ft
(7.6 m)
45° Elbow
5 ft (1.5 m)
x 1
5 ft
(1.5 m)
Roof Cap
24 ft (7.3 m)
x 1
24 ft
(7.3 m)
Straight Duct
3 ¼" x 6" (8.3 x 15 cm)
Round
1 ft (30.5 cm)
x 5
5 ft
(1.5 m)
Example Total Ductwork 119 ft (36.3 m)
GENERAL INFORMATION
2
5 / 24 EN Over The Range Microwave Oven / Installation Manual