Calculating Vent System Length
To calculate the length of the system you need, add the
equivalent feet (meters) for each vent piece used in the system.
7" (17.8 cm) Round Vent System
Vent Piece
45° elbow
90° elbow
7" (17.8 cm) wall cap
3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
to 7" (17.8 cm)
3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
to 7" (17.8 cm) 90° elbow
Example vent system
7" (17.8 cm) round
90˚ elbow
2 ft (0.6 m)
Maximum Recommended Length
1 - 90° elbow
1 - wall cap
8 ft (2.4 m) straight
Length of 7" (17.8 cm) system
6
Round
2.5 ft
(0.8 m)
5.0 ft
(1.5 m)
0.0 ft
(0.0 m)
4.5 ft
(1.4 m)
5.0 ft
(1.5 m)
Wall cap
6 ft (1.8 m)
= 50 ft (15.2 m)
= 5.0 ft (1.5 m)
= 0.0 ft (0.0 m)
= 8.0 ft (2.4 m)
= 13.0 ft (3.9 m)
3¹⁄₄" x 10" (8.3 cm x 25.4 cm) Vent System
Vent Piece
3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
90° elbow
3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
flat elbow
3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
wall cap
Example vent system
¹⁄₄
3
" x 10"
(8.3 x 25.4 cm)
elbow
6 ft (1.8 m)
2 ft
(0.6 m)
Maximum Recommended Length
1 - 90° elbow
8 ft (2.4 m) straight
1 - wall cap
Length of 3¹⁄₄" x 10" (8.3 cm x 25.4 cm)
system
5.0 ft
(1.5 m)
12.0 ft
(3.7 m)
0.0 ft
(0.0 m)
Wall cap
= 35 ft (10.7 m)
= 5.0 ft (1.5 m)
= 8.0 ft (2.4 m)
= 0.0 ft (0.0 m)
= 13.0 ft (3.9 m)