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Idiomas disponibles
Idiomas disponibles
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's sticking.
Duct Length
The total length of the duct system, including straight duct, elbows, transitions, and wall or roof caps must not
exceed 140 feet.
For best performance, do not use more than three 90 degree elbows, and keep the length as short as possible.
Below are the standard fittings and their equivalent length in feet.
To calculate the equivalent length of each duct piece used, see the examples below.
For 3 1/4" x 10" SYSTEMS
1 3 1/4" x 10" 90° elbow
1 Wall Cap
8 feet straight duct
TOTAL LENGTH
1
3 1/4" x 10"
to 6" = 5 ft.
4
5
90˚elbow
= 10 ft
6ft.
wall cap
2ft.
=
25 ft.
=
40 ft.
=
=
73 ft.
2
3 1/4" x 10" roof
cap = 24 ft
6
3 1/4" x 10"
wall cap
45˚elbow
= 40 ft
= 5 ft
Figure 10
Examples
transition
1 transition
2 90° elbows
1 Wall Cap
8 ft.
8 feet straight
TOTAL LENGTH
– 8 –
3
3 1/4" x 10" 90˚
elbow = 25 ft
7
3 1/4" x 10"
flat elbow
= 10 ft
For 6" ROUND SYSTEMS
6ft.
2ft.
wall cap
=
5 ft.
=
20 ft.
=
40 ft.
=
8 ft.
=
73 ft.
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