GE JP989 Owner's Manual & Installation Instructions page 18

Installation Instructions
DUCTWORK CALCULATIONS
Calculate Total E(
Duct Pieces
6" round
straight
31/4" x 10"
straight
C_ 6", 90 °
elbow
6", 45 °
elbow
24" max.
flexible
metal offset
adapter
31/4,,X10, "
90 ° elbow
31/4" X
10"
45 ° elbow
31/4,,X10, "
90° flat elbow
6" round
to 31/4 " x 10"
transition
uivalent Ductwork Length
Equivalent Number
Length* x Used =
1 ft. x ( )*=
1 ft. x ( F=
15 ft. x ( ) =
9ft. x ( )=
34 ft. x ( )=
16 ft. x ( ) =
5ft. x ( )=
18 ft. x ( )=
7ft. x ( )=
Subtotal Column 1 =
Equivalent
Length
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
*Equivalent lengths of duct pieces are based on
actual tests and reflect requirements for good
venting performance with any downdraft cooktop.
tMeasure and list feet of straight duct used. Count
and list the quantity of all other duct pieces for
the "Number Used" of each type.
IMPORTANT:
For maximum efficiency, use the shortest and
straightest duct run possible, with as few fittings
as possible. For satisfactory performance, the duct
run should not exceed 100 feet equivalent length.
Venting performance is improved by using larger
diameter duct.
Equivalent Number Equivalent
Duct Pieces Length* x Used = Length
6" round
to 31/4 " x 10"
transition
90 ° elbow 20 ft. x ( ) = ft.
31/4" x 10"
to 6" round
transition 5 ft. x ( ) = ft.
[_ 31/4" X
10"
to 6" round
transition
90 ° elbow 12 ft. x ( )= ft.
6" round
wall cap
with damper 21 ft. x ( ) = ft.
31/4" X
10" wall cap
with damper 27 ft. x ( ) = ft.
6" round
roof cap 20 ft. x ( ) = ft.
6" round
roof vent
24 ft. x ( ) =
Subtotal Column 2 =
Subtotal Column 1 =
TOTAL DUCTWORK =
ft,
ft.
ft.
ft.
Should not exceed 100 feet,
DO NOT use flexible plastic ducting.
Vent installation should not exceed 100 feet
equivalent length.
18