Heatilator • Novus B-Vent Series • 4055-188 • Rev. S • 3/13
17
Per
Manufacturer’s
Specifications
C
B
A
32-1/2 in.
(826 mm)
to ceiling
0 in.
0 in. TO LEVEL
OF STANDOFFS
1/2 in.
(13 mm)
Drywall
0 in.
1/2 in.
(13 mm)
Combustible Object
36 in.
(914 mm)
Combustible flooring may be installed
next to the front of the appliance.
A
Rough Opening
(Width)
B
Rough Opening
(Height)
C
Rough Opening
(Depth)
in.
36
34-7/8
19-5/8
mm
914
886
498
in.
39
34-7/8
19-5/8
mm
991
886
498
in.
42
34-7/8
19-5/8
mm
1067
886
498
in.
48
34-7/8
19-5/8
mm
1219
886
498
NBV4842I
Model
NBV3630I
NBV3933I
NBV4236I
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 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.
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, in regions where cold
air infi 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 restops
Figure 5.2
Clearances to Combustibles
C. Clearances
NOTICE: Install appliance on hard metal or wood surfaces
extending full width and depth. DO NOT install directly on
carpeting, vinyl, tile or any combustible material other than
wood.
WARNING! Risk of Fire! Maintain specifi ed air space
clearances to appliance and vent pipe:
• Insulation and other materials must be secured to
prevent accidental contact.
• The chase must be properly blocked to prevent blown
insulation or other combustibles from entering and
making contact with fi replace or chimney.
•
Failure to maintain airspace may cause overheating and
a fi re.
should be caulked with caulk with a minimum of 300ºF con-
tinuous exposure rating to seal gaps. Gas line holes and
other openings should be caulked with caulk with a mini-
mum 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 under-
neath to prevent conducting cold up into the room.
Note:
If the inside of the framed cavity is to be fi nished, the framing dimensions must include the fi nished surface. Example: If
drywall is to be attached to the rear wall, the depth must be measured from the drywall surface.
