10
combustible flooring without a separate sub-
base. Also, the furnace rear mounting plate
(see Figure 3) supplied with the duct connec-
tors is recommended for use with this type of
installation.
Selecting Duct Connector
Non Platinum Duct Connector
1.
Determine depth of floor cavity from sur-
face of floor to top of supply air duct (see
Figure 5).
2.
Select appropriate model from Table 4
which matches X-dimension of floor cavity.
To maximize air delivery, remove reducer
(C in Figure 5) to obtain largest open area
that will fit duct/floor construction.
NOTE: Duct connectors may be
installed in any one of four positions.
Platinum Duct Connector
1.
The 14” round duct connector (903896) is
designed to connect directly to a 14” flex-
duct.
Preparing Floor Opening(s)
1.
Mark floor opening(s) as shown in Figure
6. Provide minimum clearances at rear and
right side walls of closet or alcove for
installation of furnace and wiring.
2.
Cut floor opening on outside edge of marked
line so that opening is slightly larger than
area marked.
3.
Additional provisions may be necessary
for optional air conditioning or heat pump if
refrigerant lines are installed elsewhere
than at the front of the furnace.
4.
The refrigerant and entrance supply open-
ing dimensions may be adjusted ± 1/2”.
2-3/8" MIN
(60 mm)
"
6-1/4
23-3/4"
(603 mm)
20"
3/4"
"
10
14-1/2"
(368 mm)
3" (76 mm)
"
4-1/4
"
5
"
3-3/8
REAR WALL OF ENCLOSURE
Furnace Outer
Door
Optional Supply Wire
Entrance
Optional
Refrigerant
Line
(Not required
for Platinum)
Center Line
17"
(432 mm)
14-1/2"
(368 mm)
16-5/8"
(422 mm)
(254 mm)
(86 mm)
(127 mm)
(108 mm)
(159 mm)
(19 mm)
(508 mm)
3-3/4"
(95 mm)
Furnace
Outline
A/C Or HP
Figure 6. Downflow Floor Cutout Locations (nominal dimensions)
Table 4. Floor Cavity Sizes
If “X”
Use Duct Connector
floor cavity is:
Model Part Number
English
Metric (mm) Finger Tab Screw Down
7/8"
22
901987
904008
2"
51
901988
904009
4 1/4"
108
901989
904010
6 1/4"
159
901990
904011
8 1/4"
210
901991
904012
10 1/4"
260
901992
904013
12 1/4"
311
901993
904014
