Installation; Leveling Legs (If Desired); Installation On A Concrete Slab; Installation On A Combustible Floor - Carrier 58MSA Installation, Start-Up, And Operating Instructions Manual

3. When ducts are used, they must be of the same cross-sectional
area as the free area of the openings to which they connect.
The minimum dimension of ducts must not be less than 3 in.
(See Fig. 13.)

INSTALLATION

Step 1—Leveling Legs (If Desired)
When furnace is used in upflow position with side inlet(s), leveling
legs may be desired. (See Fig. 14.) Install field-supplied,
corrosion-resistant 5/16-in. machine bolts and nuts.
"
5
⁄
16
5
⁄
16
"
3
1 ⁄
4
"
5
⁄
16
"
3
1 ⁄
4
"
3
1 ⁄
4
Fig. 14—Leveling Legs
NOTE: The maximum length of bolt should not exceed 1-1/2 in.
1. Position furnace on its back. Locate and drill a 5/16-in.
diameter hole in each bottom corner of furnace. (See Fig. 14.)
Holes in bottom closure panel may be used as guide locations.
2. For each hole, install nut on bolt and then install bolt and nut
in hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install flat
washer if desired.)
4. Adjust outside nut to provide desired height, and tighten inside
nut to secure arrangement.
NOTE: Bottom closure must be used when leveling legs are used.
See Bottom Closure Panel section.
Step 2—Installation on a Concrete Slab
1. Construct hole in floor per dimensions in Fig. 15.
2. Place plenum and furnace as shown in Fig. 16.
Step 3—Installation on a Combustible Floor (Downflow

Applications)

1. Cut and frame hole in floor per dimensions in Installation
Instructions packaged with downflow subbase kit.
NOTE: Remove furnace perforated, discharge duct flanges when
they interfere with mating flanges on coil on downflow subbase.
To remove furnace perforated, discharge duct flange, use wide
duct pliers or duct flange tool to bend flange back-and-forth until
it breaks off. Be careful of sharp edges. (See Fig. 17.)
"
"
3
1 ⁄
4
"
5
⁄
16
A89014
Opening Dimensions (In.)
FURNACE
CASING WIDTH
17-1/2
21
24-1/2
* These dimensions apply when a model CD or CK Evaporator Coil casing is
to be installed.
Fig. 15—Floor Opening in Concrete Slab
Fig. 16—Furnace on a Concrete Slab
(Non-Garage Installation)
PERFORATED
DISCHARGE DUCT
FLANGE
Fig. 17—Duct Flanges
15
A
B
HOLE IN
FLOOR
B
A
Heat Only Heat/Cool*
16-7/16 19-5/8 19-7/16
19-7/8 19-5/8 19-7/16
23-7/16 19-5/8 19-7/16
FURNACE
PLENUM
210°
MIN
A73382
A73383
NO
YES
YES
A93029