Vent Diagrams - Majestic MERCURY Series Installation Manual

G. Vent Diagrams
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.
• Rear Vented: A maximum of three 90º elbows (or six 45º
elbows) may be used in any vent configuration. Some
elbows may be installed horizontally. See Figure 4.24
and 4.25.
• Top Vented: A maximum of four 90º elbows (or eight 45º
elbows) may be used in any vent configuration. Some
elbows may be installed horizontally. See Figure 4.17
and 4.18.
• Elbows may be placed back to back anywhere in the
system.
•
Any 90º elbow may be replaced with two back to back
45º elbows.
• When penetrating a combustible wall, a wall shield
firestop must be installed.
• 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.
• Horizontal termination cap should have a 1/4 inch
downward slant to allow any moisture in cap to be
released. See Figure 4.10.
1/4 in. max.
(6 mm)
Figure 4.10
18 Majestic • MERC32IN, MERC32IL Installation Manual • 2401-980 Rev. L • 1/21