Specification
For the most efcient & quiet operation:
ALWAYS, when possible, reduce the number or transitions and turns. If long duct run is required, increase•
duct size from 8” to 10” or bigger size duct. If a reducer is used, install a long reducer instead of a pancake
reducer. Reducing duct size will restrict airow and decrease airow, thus reduce duct size as far away from
opening as possible.
Use no more than three 90° elbows.•
Make sure there is a minimum of 24” (61 cm) of straight vent between the elbows if more than one elbow is used.•
DO NOT install two elbows together.•
The length of vent system and number of elbows should be kept to a minimum to provide efcient performance.•
The vent system must have a damper. If roof or wall cap has a damper, DO NOT use damper (if supplied) on top of the•
range hood.
Use silver tape or duct tape to seal all joints in the vent system.•
Use caulking to seal exterior wall or roof opening around the cap. •
Please use Duct Run Calculation below to com-
pute total available duct run when using elbows, transitions and caps.
If turns or transitions are required: Install as far away from opening and as far apart, between 2, as possible.•
If available, also refer to stove top manufacturer’s height clearance requirements and recommended hood•
mounting height above range.
* Due to different ceiling height congurations, recommended height may not be applicable.
Minimum Duct Size:
Round - 6” or 8”•
Duct Run Calculation:
Recommended maximum run
8” or 3-1/4 x 10” duct 50 ft
Vent piece deduction
Each 90º elbow used 9 ft
Each 45º elbow used 5 ft
Each 8” to 3 1/4 x 10” transition used 7 ft
Side wall cap with damper 0 ft
Roof cap 0 ft
Duct Run Calcuation example:
One roof cap, two 90º elbow, and one 45º elbow used:
0ft + 9ft + 9ft + 5ft = 23ft used.
Deduct 23ft from 50ft, 27ft maximum available for
straight duct run.
Calculating Vent System Length
To calculate the length of the system you need, deduct the equivalent feet for each vent piece used in the system
from the recommended maximum duct run.
Venting Requirements
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