Carrier 58MXA - INSTALLATION; Leveling Legs; Upflow and Downflow Installation

Do not bend duct flanges inward as shown in Fig. 15. This
will affect airflow across heat exchangers and may cause
limited cycling or premature heat exchanger failure. Remove
duct flange completely or bend it inward a minimum of 210°
as shown in Fig. 15.
2. When complete, downflow subbase, plenum, and furnace (or
coil casing when used) should be installed as shown in Fig. 16.
Step 4—Installation in Horizontal Applications
These furnaces can be installed horizontally in either horizontal
left or right discharge position. In a crawlspace, furnace can either
be hung from floor joist or installed on suitable blocks or pad.
Furnace can be suspended from each corner by hanger bolts and
angle iron supports. (See Fig. 17.) Cut hanger bolts (4 each 3/8-in.
all-thread rod) to desired length. Use 1 X 3/8-in. flat washers,
3/8-in. lockwashers, and 3/8-in. nuts on hanger rods as shown in
Fig. 17. Dimples are provided for hole locations. (See Fig. 2.)
The entire length of furnace MUST be supported when
furnace is used in a horizontal position to ensure proper
draining.
Fig. 17—Crawlspace Horizontal Application
A93304
NOTES:
ANGLE
IRON OR
EQUIVALENT
(B)
(A) ROD LOCATION
USING DIMPLE
LOCATORS
(SEE DIMENSIONAL
DWG FOR
LOCATIONS)
13
/16-IN. MAX
ALTERNATE SUPPORT
LOCATION FROM BACK
ALTERNATE SUPPORT
LOCATION 4-IN. MIN
8-IN. MAX
3
⁄8-IN. ROD
(A)
(B)
(A)
(B)
(B)
(A)
1. A 1 In. clearance minimum between top of
furnace and combustible material.

2. The entire length of furnace must be
supported when furnace is used in horizontal
position to ensure proper drainage.
(A) PREFERRED ROD LOCATION

(B) ALTERNATE ROD LOCATION
DRAIN
5
3
⁄
4
″
3
/8-IN. HEX NUT
& WASHER (4)
REQD PER ROD
Fig. 16—Furnace, Plenum, and Subbase Installed
on a Combustible Floor
A78651
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FURNACE
(OR COIL CASING
WHEN USED)
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