Heatilator • Eclipse • 4049-229 Rev I • 08/09
25
To replace the first starter elbow with two 45° elbows,
refer to Figure 7.4. All other 90° elbows can be replaced
with two 45° elbows.
General Rules:
• SUBTRACT ft. from the total H measurement for each
90° elbow installed horizontally.
• SUBTRACT -/2 ft. from the total H measurement for
each 45° elbow installed horizontally.
• A maximum of three 90° elbows (or six 45° elbows)
may be used in any vent configuration. Some elbows
may be installed horizontally. See Figure 7.9.
• Elbows may be placed back to back anywhere in the
system as long as the first 90° elbow is a starter elbow
except as shown in Figure 7.4.
• When penetrating a combustible wall, a wall shield
firestop must be installed on both sides.
• When penetrating a combustible ceiling, a ceiling
firestop must be installed.
• Horizontal runs of vent do not require vertical rise;
horizontal runs may be level.
E. Vent Diagrams
Figure 7.3
One Elbow
V
1
H
1
1. Top Vent - Horizontal Termination - (continued)
V
1
min.
V
1
max.
H
1
max.
ft
m
ft
m
ft
m
0*
-
-
.67
0.5
0.5
0.5
-
-
6
.8
0.0
-
-
.5
.5
0.46
-
-
8
5.49
2
0.6
-
-
25
7.62
-
-
25
7.62
25
7.62
* You may install elbow directly on top of appliance.
