Lennox ELITE Series Installation Instructions Manual page 6

You must consider combustion air needs and require-
ments for exhaust vents and gas pip-ing. A portion of this
information has been reprinted with permission from the
National Fuel Gas Code (ANSI Z223.1/NFPA 54). This re-
printed material is not the complete and official position of
the ANSI on the referenced subject, which is represented
only by the standard in its entirety.
In Canada, refer to the CSA B149 installation codes.
CAUTION
EL296DFV unit should not be installed in areas normally
subject to freezing temperatures.
All gas-fired appliances require air for the combustion
process. If sufficient combustion air is not available, the
furnace or other appliance will operate inefficiently and
unsafely. Enough air must be provided to meet the needs
of all fuel-burning appliances and appliances such as ex-
haust fans which force air out of the house. When fireplac-
es, exhaust fans, or clothes dryers are used at the same
time as the furnace, much more air is required to ensure
proper combustion and to prevent a downdraft. Insuffi-
cient air causes incomplete combustion which can result
in carbon monoxide
In addition to providing combustion air, fresh outdoor air
dilutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and other contaminants which can corrode furnace com-
ponents.
The requirements for providing air for combustion and
ventilation depend largely on whether the furnace is in-
stalled in an unconfined or a confined space.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the com-
bined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be
unconfined, it might be necessary to bring in outdoor air
for combustion if the structure does not provide enough air
by infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.
Confined Space
A confined space is an area with a volume less than 50
cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of
the combined input rating of all appliances installed in that
space. This definition includes furnace closets or small
equipment rooms. When the furnace is installed so that
supply ducts carry air circulated by the furnace to areas
outside the space containing the furnace, the return air
must be handled by ducts which are sealed to the furnace
casing and which terminate outside the space containing
the furnace. This is especially important when the furnace
is mounted on a platform in a confined space such as a
closet or small equipment room. Even a small leak around
the base of the unit at the platform or at the return air duct
connection can cause a potentially dangerous negative
pressure condition. Air for combustion and ventilation can
be brought into the confined space either from inside the
building or from outside.
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two spac-
es. Each opening must have a minimum free area of 1
square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas-fired equipment in the confined
space. Each opening must be at least 100 square inches
(64516 mm2). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
inches (305 mm) of the bottom. See FIGURE 4.
EQUIPMENT IN CONFINED SPACE - ALL AIR FROM INSIDE
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
NOTE - Each opening shall have a free area of at least one square inch
per 1,000 Btu (645mm
all equipment in the enclosure, but not less than 100 square inches
2).
(64516mm.
Page 6
OPENINGS
(To Adjacent
Unconfined
Space)
2
per .29kW) per hour of the total input rating of
FIGURE 4