Vermont Castings Intrepid INDVRCB Homeowner's Installation And Operating Manual page 20

Intrepid® Direct Vent - Rear Vent Gas Heater
Figure 34
Ceiling
Joists
Cut
and
Frame
Decorative
Ceiling Support
Cover
1¹⁄₂" Wood
Screws
2. If an offset is necessary
in the attic to avoid ob-
structions, it is impor-
tant to support the vent
pipe in order to avoid
excessive stress on the
elbows. Wall straps or
plumber tape may be
used for this purpose.
(Fig. 36)
3. Wherever possible, use
45° elbows instead of
90° elbows. The 45°
elbow offers less restric-
tion to the flow of flue
gases and intake air.
Step 7. Slip the roof flash-
ing over the pipe section(s)
protruding through the roof.
Use a non-hardening sealant between the roof flashing
and the roofing to prevent water leakage. Secure the
base of the roof flashing to the roof with roofing nails.
Ensure the roofing material overlaps the top edge of the
roof flashing. (Fig. 38) Verify that you have at least the
minimum clearances to combustibles at the roofline and
in the attic.
20
roofline. The galva-
nized finish is desirable
above the roofline, due
to higher corrosion
resistance.
NOTES:
1. If exact lengths or
distances must be met
between elbow offsets
or elsewhere, use the
pipe extensions to ad-
just onto standard pipe
sections. (Fig. 35)
Figure 35
Pipe
Extension
Pipe
ST986
Section
ST987
Figure 36
Wall Strap
/ Plumbers
Tape
45°
Elbow
ST988
Step 8. Continue to add pipe sections until the height of
the system (before adding the cap) meets the minimum
building codes requirements as described in Table 2,
Figure 37. Note that for steep roof pitches, the vent
height must be increased. In high wind conditions,
nearby trees, adjoin-
ing rooflines, steep
pitched roofs and
other similar factors
can result in poor
draft, or down draft-
ing. In these cases,
increasing the vent
height or switching to
the high wind termi-
nation cap may help
to solve the problem.
Roof Pitch
Flat 7/12
Over 7/12 to 8/12
Over 8/12 to 9/12
Over 912 to 10/12
Over 10/12 to 11/12
Over 11/12 to 12/12
Over 12/12 to 14/12
Over 14/12 to 16/12
Over 16/12 to 18/12
Over 18/12 to 20/12
Over 20/12 to 21/12
Step 9. Slip the storm collar over the pipe section, and
push it down to the top of the roof flashing. (Fig. 38)
Use non-hardening sealant between the storm collar
and the pipe section
Step 10. Holding the bottom of the termination cap only,
twist lock the cap onto the last pipe section protruding
above the roofline.
NOTES:
45°
1. For multi-story vertical installations, a ceiling firestop
Elbow
is required at the second floor, and any subsequent
floors. (Fig. 39) Cut and frame a 9" x 9" (229 x 229
mm) square opening for installation of the ceiling
firestop.
2. If vent passes through any occupied areas above
the first floor, including closets and storage spaces,
it must be enclosed. The enclosure may be framed
and covered with sheet rock with standard construc-
tion materials, but required clearances to combus-
tibles must be maintained. Consult these installation
instructions for the minimum allowable clearances
between the outside of the vent pipe and the com-
bustible surfaces of the enclosure. Do not fill re-
quired air spaces with insulation.
Figure 37
Dimension 'H'
from Table 2
H
ST989
Table 2
Minimum Height
ST989
1' (914 mm)
chimney height
1'6" (457 mm)
8/07
2' (610 mm)
2'6" (762 mm)
3'3" (990 mm)
4' (1.2 m)
5' (1.5 m)
6' (1.8 m)
7' (2.1 m)
7'3" (2.3 m)
8' (2.4 m)
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