22
51D0528
HORIZONTAL (THROUGH THE WALL)
TERMINATION CONFIGURATION
(Continued)
• If a 90° elbow is used in the horizontal vent run (level height
maintained) the horizontal vent length is reduced by 36"
(914 mm). This does not apply if the 90° elbows are used
to increase or redirect a vertical rise.
See Figure 27.
Example: According to the vent graph (page 16) the maxi-
mum horizontal vent length in a system with a 7.5' vertical
rise is 20’ (6m). If a 90° elbow is required in the horizontal
vent it must be reduced to 17' (5.2 m).
In Figures 25 and 26,
Dimension A plus B must not be greater
than 17' (5.2m).
• The maximum number of 45° elbows permitted per side
wall installation is two (2). These elbows can be installed
in either the vertical or horizontal run.
• For each 45° elbow installed in the horizontal run, the length
of the horizontal run MUST be reduced by 18" (45cm). This
does not apply if the 45° elbows are installed on the vertical
part of the vent system.
• The maximum number of elbow degrees in a system is 270°.
See Figure 28.
Figure 27 - Maximum Vent Run with Elbows
Example:
Elbow 1 = 90°
Elbow 2 = 45°
Elbow 3 = 45°
Elbow 4 = 90°
Total Angular Variation = 270°
Figure 26 - Horizontal Run Reduction
Figure 28 - Maximum Elbow Usage
VENT INSTALLATION
90°
A + B = 17' Maximum
90° Elbow = 3'
1 + 2 + 3 + 4 = 270°
1
2
3
4
1
2
3
4
7'6"
A
B
7'6"
10'
7'
A
B
