Heat & Glo • Crescent II • 2083-902 Rev. U • 4/15
24
To replace the
fi
rst 90º starter elbow with two 45º elbows,
refer to Figure 7.3. All other 90º elbows can be replaced
with two 45º elbows.
General Rules:
• SUBTRACT 3 ft. from the total H measurement for each
90º elbow installed horizontally.
• SUBTRACT 1-1/2 ft. from the total H measurement for
each 45º elbow installed horizontally.
• A maximum of three 90º elbows (or six 45º elbows) may
be used in any vent con
fi
guration. Some elbows may be
installed horizontally. See vent diagrams.
• Elbows may be placed back to back anywhere in the
system as long as the
fi
rst 90º elbow is a starter elbow.
• When penetrating a combustible wall, a wall shield
fi
restop must be installed.
• When penetrating a combustible ceiling, a ceiling
fi
restop
must be installed.
• Horizontal runs of vent do not require vertical rise;
horizontal runs may be level.
• Horizontal termination cap should have a 1/4 inch
downward slant to allow any moisture in cap to be
released. See Figure 7.3.
E. Vent Diagrams
Top Vent—Horizontal Termination—Two 45º Elbows
Installation requirements to replace the
fi
rst 90º elbow
with two 45º elbows:
Figure 7.3
4 ft min.
(1.22 m)
25 ft max.
(7.62 m)
1/4 in. max.
(6 mm)