GE PSA1200 Installation Instructions Manual page 5

Installation Instructions
NOTE: If you need to install ducts, note that the total duct
length of 3%" 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 3%" 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
3%" x 10" rectangular or 6" diameter round cuct 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.
will have to be cut to fit, using the tin snips, in order
to allow free movement of the damper.
EQUIVALENT NUMBER EQUIVALENT
DUCT PIECES LENGTH x USED = LENGTH
Rectangular-to-Round 5 Ft. X ( ) } = Ft
Transition Adaptor™
[ID Wall Cap AQ Ft. X ( ) } = Ft
OD 90° Elbow 10 Ft. X ( ) = Ft
Q 45° Elbow 5 Ft. Xx ( ) = Ft
cE 90° Elbow 25 Ft. xX (| = Ft
FA
45° Elbow
5 Ft
x
( )
=
Ft
vs Roof Cap 24 Ft. x ( ) - Ft
Straight Duct 6" Round or 1 Ft. X ( ) } = Ft
314" x 10" Rectangular
Total Ductwork = Ft.
* IMPORTANT: If a rectangular-to-round transition Equivalent lengths of duct pieces are based on actual tests and
— adaptor is used, the bottom corners of the damper reflect requirements for good venting performance with any vent
hood.