Ductwork table, Plan ductwork, Ductwork table plan ductwork – GE JVB65 User Manual
Page 8: Installation instructions, Plan the ductwork, Continued)
INSTALLATION INSTRUCTIONS
(continued)
8
Plan the Ductwork
1. This downdraft blower system is designed
for use with 3
1
⁄
4
″
x 10
″
ductwork (can be transitioned
to 6
″
round). Three different discharge
directions are available with side--to-side
adjustment for accurate alignment of ductwork.
2. For best performance: Choose the ducting
option which allows the shortest length of
ductwork and a minimum number of elbows and
transitions. Check location of floor joists, wall
joists, wall studs, electrical wiring or plumbing
for possible interference.
NOTE: The unit is shipped with the 3
1
⁄
4
″
x 10
″
discharge facing DOWN. See the Changing
Blower Direction section, if necessary.
Steps to Determine Flexible Ducting’s
Equivalent Length
1. Measure the actual amount of offset
(Maximum 3
″
recommended). The effect upon
airflow is dependent upon the amount of offset.
2. Calculate the equivalent ducting allowances
using:
( ___ in. offset) x (14 Ft. per inch)
= ___ Ft. equivalent length.
3. Ensure that the total equivalent length of
ducting does not exceed the maximum
recommendation of 100 feet.
Right
discharge
Down discharge
(as shipped)
Left discharge
Duct Pieces
Equivalent Length*
Duct Pieces
Equivalent Length*
3
1
⁄
4
″
x 10
″
6
″
Round
to 6
″
Round
5 ft.
Straight
1 ft. (per foot length)
Transition
6
″
Round
to 3
1
⁄
4
″
x 10
″
3
1
⁄
4
″
x 10
″
1 ft. (per foot length)
Transition
20 ft.
Straight
90° Elbow
3
1
⁄
4
″
x 10
″
to 6
″
Round
6
″
15 ft.
Transition
12 ft.
90° Elbow
90° Elbow
6
″
Round
6
″
Wall Cap
21 ft.
45° Elbow
9 ft.
with Damper
3
1
⁄
4
″
x 10
″
3
1
⁄
4
″
x 10
″
Wall Cap
27 ft.
90° Elbow
16 ft.
with Damper
3
1
⁄
4
″
x 10
″
6
″
Round
45° Elbow
5 ft.
Roof Cap
20 ft.
3
1
⁄
4
″
x 10
″
6
″
Round
90° Flat Elbow
24 ft.
Roof Vent
24 ft.
6
″
Round
to 3
1
⁄
4
″
x 10
″
7 ft.
Transition
SHOULD NOT EXCEED 100 EQUIVALENT FT.
*Equivalent lengths of duct pieces are based on actual tests conducted by
GE Evaluation Engineering and reflect requirements for good venting
performance with a downdraft rated at 500 CFM.
29
1
/
2
″
Venting Island to Outside Wall
Wall
7
″
24
″
Power
Cord provided
(on-right-hand side)