8
Pre-Installation (continued)
Follow these guidelines when installing duct work:
- Your venting system must vent to the outdoors either horizontally through the back wall (13) or vertically through the roof (14) (refer
to Fig. 5/Fig. 6/Fig. 7).
- Use round metal duct work with a uniform diameter of 6 in . (152 mm) . The total duct run in the venting system should be not more
than 10.7 m (35 ft).
- Calculate the total effective length of the duct work by adding the equivalent lengths in the table shown (Fig. 8). For each fitting used
add the length of the equivalent straight duct used in the system .
- Fasten all connections between pieces of duct with sheet metal screws and tape all joints with certified duct tape.
- If you must turn the path of the duct work using elbows, keep the number of elbows to a minimum for effective performance and use
no more than three 90° elbows. Ensure that there is a minimum of 18 in. (458 mm) of straight vent between each elbow. Elbow as far
away from the range hood’s exhaust opening as possible .
- Cap the exterior of the duct with a wall cap (15) or roof cap (16). Never use 4 in. (102 mm) laundry-type wall caps. Use caulking to
seal exterior wall or roof opening around the cap .
- The venting system must have a damper . If the roof or wall cap has a damper, do not use the damper supplied with the range hood .
Equivalent Length Chart
Type of duct
Length added
45° Elbow
36 in. (914 mm)
90° Elbow
5 ft (1 .52 m)
90° Flat Elbow
12 ft (3 .66 m)
2 x 90° Elbow
10 ft (3.05 m)
9 ft (2.74 m) Straight duct
9 ft (2.74 m)
Wall cap
0 ft (0 m)
13
15
Horizontal Wall Venting
Fig.5
Vertical Roof Venting
14
16
Fig.7
Horizontal Wall Venting
Fig.6
13
15
Fig. 8
