Heatilator • CD4236IR-D, CD4236ILR-D, CD4842IR-D, CD4842ILR-D • 2359-900 Rev. D • 5/15
22
B. Constructing the Appliance Chase
A chase is a vertical box-like structure built to enclose the
gas appliance and/or its vent system. In cooler climates
the vent should be enclosed inside the chase.
NOTICE:
Treatment of ceiling
fi
restops and wall shield
fi
restops and construction of the chase may vary with the
type of building. These instructions are not substitutes
for the requirements of local building codes. Therefore,
you MUST check local building codes to determine the
requirements to these steps.
Chases should be constructed in the manner of all out-
side walls of the home to prevent cold air drafting prob-
lems. The chase should not break the outside building
envelope in any manner.
Figure 5.2 Clearances to Combustibles
Walls, ceiling, base plate and cantilever
fl
oor of the chase
should be insulated. Vapor and air in
fi
ltration barriers
should be installed in the chase as per regional codes for
the rest of the home. Additionally, in regions where cold
air in
fi
ltration may be an issue, the inside surfaces may be
sheetrocked and taped for maximum air tightness.
To further prevent drafts, the wall shield and ceiling
fi
re-
stops should be caulked with caulk with a minimum of
300ºF continuous exposure rating to seal gaps. Gas line
holes and other openings should be caulked with caulk with
a minimum of 300ºF continuous exposure rating or stuffed
with unfaced insulation. If the appliance is being installed
on a cement surface, a layer of plywood may be placed
underneath to prevent conducting cold up into the room.
* Adjust framing dimensions for interior sheathing (such as sheetrock)
C** Add 12 inches for rear venting with one 90º elbow.
F
G
H
I
J
E
C
B
D
A
*
MINIMUM FRAMING DIMENSIONS
Models
A
B
C**
D
E
F
G
H
I
J
Rough
Opening
(Width)
Rough
Opening
(Height)
Rough
Opening
(Depth)
Rough
Opening
(Width)
Clearance
to Ceiling
Combustible
Floor
Combustible
Flooring
Behind
Appliance
Sides of
Appliance
Front of
Appliance
CD4236 Series
in.
10
40-1/8
22
42
25
0
0
1/2
1/2
36
mm
254
1019
559
1067
635
0
0
13
13
914
CD4842 Series
in.
10
42-1/8
22
49
25
0
0
1/2
1/2
36
mm
254
1019
559
1245
635
0
0
13
13
914
COMBUSTIBLE FLOORING MAY BE INSTALLED
NEXT TO THE FRONT OF THE APPLIANCE.