18-CD32D1-3
9
Installer’s Guide
7
50 CU. FT. OR MORE
PER 1000 BTU/HR. INPUT
ALL EQUIP. INSTALLED
UNCONFINED
8
CONFINED
LESS THAN 50 CU. FT.
PER 1000 BTU/HR. INPUT
ALL EQUIP INSTALLED
9
Typical Suspended Upflow/Horizontal Furnace
IMPORTANT:
Limited Warranty is conditional upon proper furnace and
vent system application and installation. Downflow fur-
naces installed in the vertical or horizontal position may
be vented through top or right side of the furnace cabinet
only (see figure 6 for defined top, left and right). A 90 de-
gree elbow may be installed inside the cabinet and rotated
so the vent pipe entering through the right side furnace
cabinet cutout can be connected to the elbow. Right side
venting may be used to provide access if an electronic
air cleaner is installed. Left side venting must use a 90
degree elbow outside the cabinet (Figure 6).
AIR FOR COMBUSTION AND VENTILATION
Adequate flow of combustion and ventilating air must not
be obstructed from reaching the furnace. Air openings
provided in the furnace casing must be free of obstructions
which restrict the flow of air. Airflow restrictions affect
the efficiency and safe operation of the furnace. Keep this
in mind should you choose to remodel or change the area
which contains your furnace. Furnaces must have a free
flow of air for proper performance.
Provisions for combustion and ventilation air shall be
made in accordance with “latest edition” of Section 5.3, Air
for Combustion and Ventilation, of the National Fuel Gas
Code, ANSI Z223.1, or Sections 7.2, 7.3 or 7.4 of CAN/CGA
B149 Installation Codes, and applicable provisions of the
local building codes. Special conditions created by mechani-
cal exhausting of air and fireplaces must be considered to
avoid unsatisfactory furnace operation.
Furnace locations may be in “confined space” or “unconfined
space”. Unconfined space is defined in Table 2 and Figure
8. These spaces may have adequate air by infiltration to
provide air for combustion, ventilation, and dilution of
flue gases. Buildings with tight construction (for example,
weather stripping, heavily insulated, caulked, vapor bar-
rier, etc.), may need additional air provided as described for
confined space.
Confined spaces are installations with less than 50 cu. ft. of
space per 1000 BTU/hr input from all equipment installed.
Air for combustion and ventilation requirements can be
supplied from inside the building as in Figure 9 or from the
outdoors, as in Figure 10.
1. All air from inside the building as in Figure 9: The
confined space shall be provided with two permanent
openings connected directly to an additional room(s)
of sufficient volume so that the combined volume of all
spaces meets the criteria for an unconfined space. The
total input of all gas utilization equipment installed in
the combined space shall be considered in making this
determination. Refer to Table 3, for minimum open
areas required.
2. All air from outdoors as in Figure 11: The confined
space shall be provided with two permanent open-
ings, one commencing within 12 inches of the top and
one commencing within 12 inches of the bottom of the
enclosure.
The openings shall be connected directly, or by ducts,
with the outdoors or spaces (crawl or attic) that freely
connect to the outdoors. Refer to Table 3, for minimum
open areas required.
3. The following types of installations will
require
use
of OUTDOOR AIR for combustion, due to chemical
exposures:
* Commercial buildings
* Buildings with indoor pools
* Furnaces installed in commercial laundry rooms
* Furnaces installed in hobby or craft rooms
* Furnaces installed near chemical storage areas.
Exposure to the following substances in the combustion
air supply will also require OUTDOOR AIR for combus-
tion:
* Permanent wave solutions
* Chlorinated waxes and cleaners
* Chlorine based swimming pool chemicals
* Water softening chemicals
* Deicing salts or chemicals
* Carbon Tetrachloride
* Halogen type refrigerants
* Cleaning solvents (such as perchloroethylene)
* Printing inks, paint removers, varnish, etc.
* Hydrochloric acid
* Cements and glues
* Antistatic fabric softeners for clothes dryers
* Masonry acid washing materials
