Lennox SL280DFNV Installation Instructions Manual page 9

UNIT
PROPERLY
SIZED FLOOR
OPENING
FIGURE 8
TABLE 2
COMBUSTIBLE FLOOR OPENING SIZE
Cabinet Front to Rear
Width
in
B (17.5") 22
C (21") 22
2 - After opening is cut, set combustible flooring base
into opening.
3 - Check sealing strips on combustible flooring base to
make sure they are properly glued and positioned.
4 - Lower supply air plenum into downflow combustible
flooring base until plenum flanges seal against the
strips.
NOTE - Be careful not to damage sealing strips. Check
for a tight seal.
5 - Set the furnace over the plenum.
6 - Ensure that the seal between the furnace and plenum
is adequate.
Installation on Cooling Cabinet (Figure 9)
1 - Refer to reverse-flow coil installation instructions for
correctly sized opening in floor and installation of
cabinet.
NOTE - Downflow combustible flooring kit is not used.
2 - When cooling cabinet is in place, set and secure
the furnace according to the instructions that are
provided with the cooling coil. Secure the furnace
to the cabinet.
3 - Seal the cabinet and check for air leaks.
SUPPLY AIR PLENUM
DOWNFLOW
COMBUSTIBLE
FLOORING BASE
Side to Side
mm in mm
559 18-3/4 476
559 22-3/4 578
PROPERLY
SIZED FLOOR
OPENING
Return Air Opening -- Downflow Units
The following steps should be taken when installing ple-
num:
1 - Bottom edge of plenum should be flanged with a
hemmed edge (See figure 10).
PLENUM
Side View
SEALING STRIP
(Field Provided)
2 - Sealing strip should be used.
3 - In all cases, plenum should be secured to top flanges
of furnace with sheet metal screws.
4 - In closet installations, it may be impossible to install
sheet metal screws from the outside. In this case,
make plenum with a removable front and install
screws from the inside (See figure 11).
5 - Make certain that an adequate seal is made.
SIDE CABINET
FIBERGLASS
SEALING STRIP
CABINET SIDE
(Field Provided)
Page 9
UNIT
COOLING COIL
PLENUM
FIGURE 9
SECURE FROM
OUTSIDE CABINET
HEMMED EDGE
CABINET SIDE PANEL
FIGURE 10
PLENUM
Side View
HEMMED EDGE
PANEL
FIGURE 11