Installation guide

STEP 2:
PREPARE THE VENTING SYSTEM
STANDARD FITTINGS
NOTE: If the existing duct is round, you must use a rectangular-to-round adapter, with a rectangular 3" extension
duct installed between the damper assembly and the adapter to prevent the exhaust damper sticking.
DUCT LENGTH
The total length of the duct system, including straight duct, elbows, transitions, wall or roof caps must not
exceed the equivalent of 140 feet.
For best performance, do not use more than three 90 degree elbows.
Below are the standard fittings and their equivalent length in feet.
EB
HSITSNa
3 1/4’ x 10” to 6" = 5 ft. 3 1/4’ x 10” roof cap = 24 ft 3 1/4” x 10” 90° elbow = 25 ft
RS
oT N22
90°elbow = 10 ft 3 1/4” x 10” wall cap 45’elbow = 5 ft 3-1/4” x 10” flat elbow
= 40 ft =10ft
Figure 9
To calculate the equivalent length of each duct piece used, see the examples below.
For 3-1/4" x 10" SYSTEMS Examples For 6" ROUND SYSTEMS
90° elbows j~—— — wall cap
3-1/4'x10" |
90"
elbow
aoe
eee
iv
4
4 iti Ott.
oft. transition +L
'
1 3-1/4” x 10” 90° elbow = 25 ft. 1 transition = 5 ft.
1 Wall Cap = AO ft. ; Wal Coe ® = ao r
. _ all Cap = .
8 feet straight duct = 8 ft. 8 feet straight - 8 tt.
TOTAL LENGTH = 73 ft. TOTAL LENGTH = 73 ft.