Heatilator • CNXT Series • 4000-011 Rev N • 11/05
21
WA
L
L
No combustible
framing to be
located within
shaded area.
2 x 4 or
2 x 6
header
Drywall
3 in.
(72 mm)
1 in. (25 mm)
1/2 in. (13 mm) min.
to perpendicular wall.
B. Wall Penetration Framing
• Frame a hole in a combustible wall for an interior wall
shield fi restop (Figures 6.1 through 6.3) whenever a wall
is penetrated. Use same size framing materials as those
used in the wall construction. The wall shield fi restop
maintains minimum clearances and prevents cold air
infi ltration.
• If the hole being penetrated is surrounded by non-
combustible materials such as concrete, a hole with
diameter 1 in. greater than the pipe is acceptable.
A. Pipe Clearances to Combustibles
Fire Risk
Explosion Risk
Maintain vent clearance to combustibles as
specifi ed.
• Do not pack air space with insulation or
other materials.
Failure to keep insulation or other materials
away from vent pipe may cause fi re.
WARNING
Figure 6.1
Pipe Clearances
3 in. (76 mm)
top clearance
1 in. (25 mm)
clearance
bottom & sides
Heat
Shield
Wall
Shield
Firestop
Heat
Shield
WALL
Note:
Heat shields
MUST overlap by a
minimum of
1-1/2 in. (38 mm).
Figure 6.2
Horizontal Venting Clearances to Combustible Materi-
als
6
6
Vent Clearances and Framing
E*
Framing should be
constructed of 2 X 4
lumber or heavier.
The center of the
framing hole is
1 in. [25mm] above
the center of the
horizontal vent pipe.
Vent
framing
hole.
D*
* Center of pipe
10 in.
12 in.
Figure 6.3
Exterior Wall Hole
Model #
D
Top Vent
E
Rear Vent
CNXT70I
in.
42-1/4
27-1/4
mm
1073
692
CNXT90I
in.
48-1/4
27-1/4
mm
1226
692