Lennox SL280DFNV Installation Instructions Manual page 8

EQUIPMENT IN CONFINED SPACE
(All Air Through Ventilated Attic)
CHIMNEY
OR GAS
VENT
OUTLET
AIR
FURNACE
AIR FLOW
NOTE-The inlet and outlet air openings shall each have a
free area of at least one square inch (645 mm
ment in the enclosure.
FIGURE 5
CHIMNEY
OR GAS
VENT
FURNACE
AIR FLOW
NOTE - Each air duct opening shall have a free area of at least
2
one square inch (645 mm
the total input rating of all equipment in the enclosure. If the
equipment room is located against an outside wall and the air
openings
ing shall have a free area of at least one square inch (645 mm
per 4,000 Btu (1.17 kW) per hour of the total input rating of all
other equipment in the enclosure.
FIGURE 6
Downflow Installation
Downflow unit installs in three ways: on non-combustible
flooring, on combustible flooring using a downflow com-
bustible flooring base, or on a reverse-flow cooling cabi-
net. Do not drag the unit across the floor.
ALL AIR FROM OUTSIDE
VENTILATION LOUVERS
(Each end of attic)
INLET AIR
(Ends 12 in.
above bottom)
WATER
HEATER
2
) per 4,000
EQUIPMENT IN
CONFINED SPACE
ALL AIR FROM
OUTSIDE
WATER
HEATER
OUTLET AIR
INLET AIR
) per 2,000 Btu (.59 kW) per hour of
Installation on Non-Combustible Flooring (Figure 7)
1 - Cut floor opening keeping in mind clearances listed
on unit rating plate. Also keep in mind gas supply
connections, electrical supply, flue and air intake
connections and sufficient installation and servicing
clearances. See table 1 for correct floor opening
size.
2 - Flange warm air plenum and lower the plenum into
the opening.
3 - Set the unit over the plenum and seal the plenum to
the unit.
4 - Ensure that the seal is adequate.
OPENING
NON-COMBUSTIBLE FLOOR OPENING SIZE
Cabinet
Width
B (17.5")
C (21")
NOTE - Door opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See unit dimensions on page 2.
Installation on Combustible Flooring (Figure 8)
1 - When unit is installed on a combustible floor,
a downflow combustible flooring base must be
installed between the furnace and the floor. The
2
)
base must be ordered separately. See table 2 for
opening size to cut in floor.
The furnace and downflow combustible flooring
base shall not be installed directly on carpeting,
tile, or other combustible material other than wood
flooring.
Page 8
UNIT
FIGURE 7
TABLE 1
Front to Rear
in mm
19-3/4 502 16-1/4
19-3/4 502 19-3/4
CAUTION
SUPPLY AIR
PLENUM
Side to Side
in mm
413
502