Ductwork Calculations - GE JGP989 Owner's Manual & Installation Instructions

Calculate Total Equivalent Ductwork Length
Equivalent
Duct Pieces Length* x
6" round
straight 1 ft.
" x 10"
3 1 ⁄
4
straight 1 ft.
6", 90°
elbow 15 ft.
6", 45°
elbow 9 ft.
24" max.
flexible
metal offset
adapter 34 ft.
" x 10"
3 1 ⁄
4
90° elbow 16 ft.
" x 10"
3 ⁄
1
4
45° elbow 5 ft.
" x 10"
3 1 ⁄
4
90° flat elbow 18 ft.
6" round
" x 10"
to 3 ⁄
1
4
transition 7 ft.
Subtotal Column 1 =
*Equivalent lengths of duct pieces are based on
actual tests and reflect requirements for good
venting performance with any downdraft cooktop.
†Measure 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.
Installation Instructions

DUCTWORK CALCULATIONS

Number Equivalent
Used = Length
x ( ) † = ft.
x ( ) † = ft.
x ( ) = ft.
x ( ) = ft.
x ( ) = ft.
x ( ) = ft.
x ( ) = ft.
x ( ) = ft.
x ( ) = ft.
ft.
Duct Pieces
6" round
" x 10"
to 3 1 ⁄
4
transition
90° elbow
" x 10"
3 1 ⁄
4
to 6" round
transition
" x 10"
3 1 ⁄
4
to 6" round
transition
90° elbow
6" round
wall cap
with damper 21 ft.
" x 10"
3 ⁄
1
4
wall cap
with damper 27 ft.
6" round
roof cap
6" round
roof vent
DO NOT use flexible plastic ducting.
Vent installation should not exceed 100 feet
equivalent length.
20
Equivalent Number Equivalent
Length* x Used = Length
20 ft. x ( ) =
5 ft. x ( ) =
12 ft. x ( ) =
x ( ) =
x ( ) =
20 ft. x ( ) =
24 ft. x ( ) =
Subtotal Column 2 =
Subtotal Column 1 =
TOTAL DUCTWORK =
Should not exceed 100 feet.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.