Installation Instructions
13
DUCTWORK LENGTH AND DUCT FITTINGS

NOTE: Do not exceed 150 foot maximum permissible equivalent lengths!

Flexible ducting: If flexible metal ducting is used, all equivalent feet values in the table should be

doubled. The flexible metal duct should be straight and smooth and extended as much as possible.

DO NOT use flexible plastic ducting.

Add equivalent lengths for all duct pieces and transitions used to ensure that the duct run does not

exceed the maximum 150 feet.

Duct Equivalent Duct Equivalent Duct Equivalent
Pieces Length* Pieces Length* Pieces Length*
31⁄4″x 10″
to 6″Round
6″Round 1 ft. (per 31⁄4″x 10″Transition 4 ft.
Straight foot length) 45° Elbow 8 ft. 90° Elbow
6″Round
31⁄4
″x 10″1 ft. (per 31⁄4
″x 10″Wall Cap 24 ft.
Straight foot length) 90° Flat Elbow 33 ft. with Damper
6″Round 31⁄4″x 10″
6″12 ft. to 31⁄4″x 10″2 ft. Wall Cap 24 ft.
90° Elbow Transition with Damper
31⁄4
″x 10″
6″to 6″Round 2 ft. 6″Round
45° Elbow 7 ft. Transition Roof Cap 33 ft.
6″Round
to 31⁄4″x 10″
31⁄4″x 10″Transition 4 ft.
90° Elbow 14 ft. 90°Elbow
SHOULD NOT EXCEED 150 EQUIVALENT FEET
*Equivalent lengths of duct pieces are based on actual tests conducted by GE Evaluation Engineering
and reflect requirements for good venting performance. See chart for CFM Duct Length.