7
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
Round
45° elbow
2.5 ft
(0.8 m)
90° elbow
5.0 ft
(1.5 m)
7" (17.8 cm) wall cap
0.0 ft
(0.0 m)
3¹⁄
4
" x 10" (8.3 cm x 25.4 cm)
to 7" (17.8 cm)
4.5 ft
(1.4 m)
3¹⁄
4
" x 10" (8.3 cm x 25.4 cm)
to 7" (17.8 cm) 90° elbow
5.0 ft
(1.5 m)
Example vent system
Maximum Recommended Length
= 50 ft (15.2 m)
1 - 90° elbow
= 5.0 ft (1.5 m)
1 - wall cap
= 0.0 ft (0.0 m)
8 ft (2.4 m) straight
= 8.0 ft (2.4 m)
Length of 7" (17.8 cm) system
= 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
5.0 ft
(1.5 m)
3¹⁄
4
" x 10" (8.3 cm x 25.4 cm)
flat elbow
12.0 ft
(3.7 m)
3¹⁄
4
" x 10" (8.3 cm x 25.4 cm)
wall cap
0.0 ft
(0.0 m)
Example vent system
Maximum Recommended Length
= 35 ft (10.7 m)
1 - 90° elbow
= 5.0 ft (1.5 m)
8 ft (2.4 m) straight
= 8.0 ft (2.4 m)
1 - wall cap
= 0.0 ft (0.0 m)
Length of 3¹⁄
4
" x 10" (8.3 cm x 25.4 cm)
system
= 13.0 ft (3.9 m)
Electrical Requirements
Observe all governing codes and ordinances.
Ensure that the electrical installation is adequate and in
conformance with National Electrical Code, ANSI/NFPA 70
(latest edition), or CSA Standards C22.1-94, Canadian Electrical
Code, Part 1 and C22.2 No. 0-M91 (latest edition) and all local
codes and ordinances.
If codes permit and a separate ground wire is used, it is
recommended that a qualified electrician determine that the
ground path is adequate.
A copy of the above code standards can be obtained from:
National Fire Protection Association
1 Batterymarch Park
Quincy, MA 02169-7471
CSA International
8501 East Pleasant Valley Road
Cleveland, OH 44131-5575
Wall cap
7" (17.8 cm) round
90˚ elbow
2 ft (0.6 m)
6 ft (1.8 m)
Wall cap
3
¼
" x 10"
(8.3 x 25.4 cm)
elbow
2 ft
(0.6 m)
6 ft (1.8 m)
