17
17
‘H’
Horizontal
overhang
Vertical
wall
Termination
cap
Storm
collar
Roof
flashing
Plumber’s tape
fixed to wall strap
Wall strap
Ceiling
firestop
Ceiling
support
Offset elbows
Min.
18”
Overhang should
not extend beyond
vent if within 48” of
termination cap
Min. 24”
(unvented soffit)
Min. 36”
(vented soffit)
Roof Pitch
Minimum
‘H’ (feet)
Flat to 7/12
1’
Over 7/12 to 8/12
1.5’
Over 8/12 to 9/12
2’
Over 9/12 to 10/12
2.5’
Over 10/12 to 11/12
3.25’
Over 11/12 to 12/12
4’
Over 12/12 to 14/12
5’
Joists
10”
(254 mm)
10”
(254 mm)
Co-Axial Venting
Co-Axial Vertical Installations
• Check the roof pitch to determine which roof
fl
ashing will be needed. See venting accessories list
on pages 37–38 for allowable components.
• The distance from the roof to the lowest terminal
discharge opening (“H” in
fi
gure) depends on
the roof pitch and must be in accordance with
the manufacturer’s instructions supplied with the
termination unit.
Note: The venting system for these appliances is
considered to be a
Special Venting System
. The
rule in the Installation Code requiring a minimum
vent height of 2 feet above any portion of a building
within 10 feet does not therefore apply.
• The minimum clearances to combustible materials
all round the vent pipes must be in accordance
with the dimensions shown in the
Co-Axial Venting
section of this manual.
• Drop a plumb from the ceiling to the center of the
appliance vent opening. Mark the position on the
ceiling. Drill a small hole at the marked position.
• Determine the position where the vent will pass
through the roof. If directly above the position where
it penetrates the ceiling, drop a plumb from the roof
to the small hole in the ceiling and mark the roof at
this spot.
If rafters or other obstructions will prevent a vertical
exit or if clear attic space is desired, the roof outlet
can be offset using 45 degrees elbows.
Drill a small hole at the marked position.
• A
ceiling
fi
restop must be installed at the second
fl
oor and higher
fl
oors.
A ceiling support should be used below the
fl
at
ceiling.
To install the
fi
restop and support, cut and frame a
10 inches (254 mm) square hole centered on the
small hole previously drilled.
• Fit vent accessory elbows and pipe lengths as
required up through ceiling support boxes and
fi
restops.
If installation includes offset, support the offsetting
pipes every 3 feet (1 m) with wall straps as shown.
• Cut a hole in the roof centered on the small hole.
The hole must allow for the minimum clearances to
combustible materials. See
Venting
section in this
manual.
• Fit pipe lengths through the roof. Fit roof
fl
ashing
securing it with roo
fi
ng nails.
• Fit storm collar and termination cap.
Through the roof installation
Firestop hole
