14
STEP 8.
Continue to add pipe sections until the height of the vent
cap meets the minimum code requirements. Refer to
Figure 16 and Table 3. Note that for steep roof pitches, the
vent height must be increased. In high wind conditions,
nearby trees, adjoining roof lines, steep pitched roofs,
and other similar factors can result in poor draft, or down
drafting. In these cases, increasing the vent height may
solve the problem.
STEP 9.
Slip the storm collar over the pipe, and push it down to
the top of the roof flashing as shown in Figure 15. Use
the non-hardening sealant around the joint between the
pipe and the storm collar.
STEP 10.
Twist-lock the vent cap.
NOTES:
(1)
If an offset is necessary in the attic to avoid obstructions, it
is important to support the vent pipe every 3 feet (91 cm), to
avoid excessive stress on the elbows, and possible separation.
Wall straps are available for this purpose (see Figure 17).
(2)
When ever possible, use 45
°
degree elbows instead of 90
°
degree elbows. The 45
°
degree elbow offers less restriction to
the flow of flue gases and intake air.
Initial Installation
QUALIFIED INSTALLERS ONLY
NOTES:
(1)
For multi story installations. A ceiling firestop is
required at the second floor, and any subsequent
floors (see Figure 14). The opening should be framed
to 10” (25.4 cm) x 10” (25.4 cm) inside dimensions,
in the same manner as shown in Figure 14.
(2)
Any occupied areas above the first floor, including
closets and storage spaces, which the vertical vent
passes through, must be enclosed. The enclosure
may be framed and sheetrocked with standard
building materials. However consult the appliance
manufactures installation instructions for the
minimum allowable clearance between the outside
of the vent pipe, and the combustible surfaces of the
enclosure. Do not fill any required air spaces with
insulation.
Figure 17: Use of Wall Straps.
Figure 18: Multi-Story Vent Pipe Installation.
