Vissani QR254 Series Owner's Manual page 8

Pre-Installation (continued)
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 7 in (177 mm). The total duct run in the venting system should not be more
than 35 ft (10.7 m).
used add the length of the equivalent straight duct used in the system.
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.
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.
Horizontal Wall Venting
Fig.5
For interior venting system (air does not exhaust to outdoors) (Fig. 8):
installation section for more details.
17
QR254 (SERIES)
Horizontal Wall Venting
15
13
Fig.6
Fig. 8
15
13
Equivalent Length Chart
Type of duct
45° Elbow
90° Elbow
90° Flat elbow
9 ft (2.74 m) Straight duct
Wall cap
8
Vertical Roof Venting
16
14
Fig.7
Length added
3 ft (0.91 m)
5 ft (1.52 m)
12 ft (3.66 m)
9 ft (2.74 m)
0 ft (0 m)
Fig. 9