GE JVB96, JVB34, JVB64 Plan the Ductwork, Steps to Determine Flexible Ducting’s Equivalent Length

INSTALLATION INSTRUCTIONS

(continued)

Plan the Ductwork

Right discharge

Left discharge

Down discharge (as shipped)

1.This downdraft blower system is designed

″x 10″ ductwork (can be transitioned

″round). Three different dischargefor use with 31⁄4to 6

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 31⁄4″ 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.

Venting Island to Outside Wall
Wall
24″ Power
Cord provided
(on-right-hand side)	291/2″
7″

Duct Pieces	Equivalent Length*	Duct Pieces	Equivalent Length*
		31⁄4″ x 10″
6″ Round	1 ft. (per foot length)	to 6″ Round	5 ft.
Straight		Transition
		6″ Round
31⁄4″ x 10″		to 31⁄4″ x 10″	20 ft.
	1 ft. (per foot length)	Transition
Straight		90° Elbow
		31⁄4″ x 10″
6″		to 6″ Round	12 ft.
	15 ft.	Transition
90° Elbow		90° Elbow
6″		6″ Round
	9 ft.	Wall Cap	21 ft.
45° Elbow		with Damper
31⁄4″ x 10″		31⁄4″ x 10″
	16 ft.	Wall Cap	27 ft.
90° Elbow		with Damper
31⁄4″ x 10″	5 ft.	6″ Round	20 ft.
45° Elbow		Roof Cap
31⁄4″ x 10″	24 ft.	6″ Round	24 ft.
90° Flat Elbow		Roof Vent
6″ Round		SHOULD NOT EXCEED 100 EQUIVALENT FT.
to 31⁄4″ x 10″	7 ft.	*Equivalent lengths of duct pieces are based on actual tests conducted by
Transition		GE Evaluation Engineering and reflect requirements for good venting
		performance with a downdraft rated at 500 CFM.

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