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Page 12
TABLE 2
COMBUSTIBLE FLOORING BASE OPENING SIZE
Cabinet
Width
Catalog
Number
Front to Rear
Side to Side
in.
mm
in.
mm
B Cabinet
(17.5”)
11M60
22
559
18 - 3/4
476
C Cabinet
(21”)
11M61
22
559
22 - 3/4
578
FIGURE 16
FURNACE
SUPPLY AIR
PLENUM
COMBUSTIBLE
FLOORING BASE
PROPERLY
SIZED FLOOR
OPENING
2 - After opening is cut, set the combustible flooring base
into opening.
3 - Check fiberglass strips on the combustible flooring
base to make sure they are properly glued and posi
tioned.
4 - Lower supply air plenum into the combustible flooring
base until plenum flanges seal against fiberglass
strips.
NOTE
- Be careful not to damage fiberglass 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 Coil Cabinet Figure 17
NOTE
- Downflow combustible flooring kit is not used.
1 - Refer to reverse-flow coil installation instructions for
correctly sized opening in floor and installation of cabi
net.
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.
FIGURE 17
COOLING COIL
PLENUM
PROPERLY
SIZED FLOOR
OPENING
FURNACE
Return Air Opening -- Downflow Units
Return air may be brought in only through the top opening
of a furnace installed in the downflow position. The follow
ing steps should be taken when installing plenum:
1 - Bottom edge of plenum should be flanged with a
hemmed edge (See figure 18 or 19).
2 - Sealing strips should be used to ensure an airtight seal
between the cabinet and the plenum.
3 - In all cases, plenum should be secured to top of fur
nace using sheet metal screws.
4 - Make certain that an adequate seal is made.
ÉÉÉÉ
FIGURE 18
SECURE FROM
OUTSIDE CABINET
PLENUM
(Field Provided)
SEALING STRIP
(Field Provided)
Side View
CABINET
SIDE PANEL
ÉÉÉÉ
SECURE FROM
INSIDE CABINET
PLENUM
(Field Provided)
SEALING STRIP
(Field Provided)
Side View
CABINET
SIDE PANEL
FIGURE 19