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112127-01C
15
ventinG instaLLation
Continued
Note: If the vent pipe passes through any oc-
cupied areas above the first floor, including
storage spaces and closets, you must enclose
pipe. You may frame and sheetrock the en-
closure with standard construction material.
Make sure and meet the minimum allowable
clearances to combustibles. Do not fill any of
required air spaces with insulation.
Cathedral Ceiling Installation
1. Remove shingles or other roof covering as
necessary to cut the rectangular hole for the
support box. Mark the outline of the cathe-
dral ceiling support box on roof sheathing
using locating hole as a center point.
2. Cut the hole 1/8" larger than the support
box outline (see Figure 22).
3. Lower support box through the hole in
roof until bottom of box extends at least
2" below the ceiling (see Figure 22). Align
support box vertically and horizontally us
-
ing a level. Temporarily tack support box
in place through inside walls and into roof
sheathing.
4. Using tin snips, cut support box from
top corners down to roofline and fold
resulting flaps over roof sheathing (see
Figure 23). Apply a bead of nonhardening
mastic around top edges of support box to
make a seal between box and roof. Nail
in place with roofing nails. Remove any
combustible material that might be inside
of support box.
5. Complete cathedral ceiling installation by
following the same procedures outlined in
steps 2 through 7 for
Flat Ceiling Installa-
tion
, page 14.
Venting with Two 90° Elbow
Vertical (V) Horizontal (H)
5' min.
2' max.
6' min.
4' max.
7' min.
6' max.
8' min.
8' max.
20' max.
8' max.
Figure 24 - Vertical Venting
Configuration Using Two 90° Elbow
Note: Install
restrictor into
4" collar of
burner system
as shown.
Figure 22 - Cathedral Ceiling Support
Box Installation
Nonhardening mastic
under all edges of support
box before nailing
Figure 23 - Installed Cathedral Ceiling
Support Box
Cut hole 1/8" larger than support box
when projected onto roofline
2" minimum below
finished ceiling
Cathedral
Ceiling
Support Box
Level
Vertical Termination Configurations
Figure 24 through 27 show four different con-
figurations for vertical termination.
