Heatilator • CNXT Series • 4000-011 Rev N • 11/05
7
B. Construct the Appliance Chase
A chase is a vertical boxlike structure built to enclose the gas
appliance and/or its vent system. Vertical vents that run on
the outside of a building may be, but are not required to be,
installed inside a chase.
Construction of the chase may vary with the type of build-
ing. These instructions are not substitutes for the require-
ments of local building codes. Local building codes MUST
be checked.
Chases should be constructed in the manner of all outside
walls of the home to prevent cold air drafting problems. The
chase should not break the outside building envelope in any
manner.
Walls, ceiling, base plate and cantilever fl oor of the chase
should be insulated. Vapor and air infi ltration barriers should
be installed in the chase as per regional codes for the rest of
the home. Additionally, Hearth & Home Technologies recom-
mends that the inside surfaces be sheetrocked and taped for
maximum air tightness.
To further prevent drafts, the ceiling fi restops should be
caulked with high temperature caulk to seal gaps. Gas line
holes and other openings should be caulked with high temp
caulk or stuffed with unfaced insulation. If the appliance is
being installed on a cement slab, we recommend that a layer
of plywood be placed underneath to prevent conducting cold
up into the room.
Fire Risk
Odor Risk
• Install appliance on hard metal or wood
surfaces extending full width and depth
of appliance.
• Do NOT install appliance directly on
carpeting, vinyl, tile or any combustible
material other than wood.
WARNING
Fire Risk
• Construct chase to all clearance
specifi cations in manual.
• Locate and install appliance to all
clearance specifi cations in manual.
WARNING
Measured from top of
fireplace opening (in inches)
1 - 3
4 - 6
7 - 9
10- 12
9-1/2
12-1/2
15-1/2
18-1/2
34-1/2 in.
minimum
to ceiling
12 in. is the maximum
mantel projection allowed.
Figure 3.2
Clearances to Mantels or Other Combustibles Above
Appliance
1 in. (25 mm) min.
to perpendicular wall
A
3-1/2 in. (89 mm) min.
from fireplace opening
to perpendicular wall
B
48 in.
(1219 mm)
max.
Mantel Leg or
Perpendicular Wall
Top of
Appliance
Drywall
A
B
Figure 3.3
Clearances to Mantel Legs or Wall Projections (Accept-
able on both sides of opening)
C. Mantel Projections
12 in. (305 mm) is the maximum
mantel projection allowed.
