Installation Instructions

Page 2L124 1211A

Ducting Do’s and Don’ts

NEVER restrict the duct size. The single blower unit (B100) requires 6” round duct or equivalent

(28 square inches), and the dual blower unit (B200) requires 8” round duct or equivalent (50

square inches). Using Vent-A-Hood transitions (back page) will ensure proper efciency.

Blower Duct Size Sq. Inch Area Vent-A-Hood Transition

Single (B100) 6” round or equivalent 28” N/A

Dual (B200) 8” round or equivalent 50” N/A

Do not use exible or corrugated duct. This type of duct will restrict airow and reduce

performance. Only use smooth, galvanized, metal duct. Observe local codes regarding special

duct requirements and placement of duct against combustibles. Make the duct run as short

and as straight as possible with as few turns as possible. Avoid sharp-angled turns. Instead,

use smooth, gradual turns such as adjustable elbows or 45 degree angled turns. For duct runs

over 20 feet, increase the duct diameter by one inch for every ten feet of duct. A 90 degree

elbow is equal to 5 feet of duct. Using Vent-A-Hood roof jacks or wall louvers (back page) will

ensure proper efciency. Airow must not be restricted at the end of the duct run. Do not use

screen wire or spring-loaded doors on wall louvers or roof jacks. Do not terminate venting into

an attic or chimney. Where possible, seal joints with duct tape. The hood must be ducted to the

outdoors without restrictions.

YES

Smooth Duct

Smooth Gradual Turn

Flexible Duct

Sharp Angled Turns