GE JVM1665, Installation Instructions Manual

Page: 5 / 48

EQUIVALENT NUMBER EQUIVALENT
DUCT PIECES LENGTH x USED = LENGTH
Rectangular-to-Round 5 Ft. x ( ) = Ft.
Transition Adapter*
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.
3
1
⁄
4
″
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
Adapter 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 3 1 ⁄
4
″
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 3
1
⁄
4
″
x 10
″
rectangular duct.
If a round duct is required, a rectangular-to-round
transition Adapter must be used.
Do not use less
than a 6
″
diameter duct.
Maximum duct length:
For satisfactory air movement, the total duct length
of 3
1 ⁄
4
″
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
adapters 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