Furnace Location Relative To Cooling Equipment; Hazardous Locations; Installation; Leveling Legs (If Desired) - Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual

FRONT
RETURN
AIR
NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to 55°F
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to follow
these return-air temperature limits may affect reliability of heat
exchangers, motors, and controls.
FRONT
BACK
FRONT
Do not install furnace on its back. Safety control operation
will be adversely affected. Never connect return-air ducts to
back of furnace. Failure to follow this warning could result in
fire, personal injury, or death.
Provide ample space for servicing and cleaning. Always comply
with minimum fire protection clearances shown on units clearance
to combustibles label. (See Fig. 3.) Locate furnace where available
electric power and gas supplies meet specifications on furnace
rating plate.
Step 2—Furnace Location Relative to Cooling
Equipment
The cooling coil must be installed parallel with or on downstream
side of furnace to avoid condensation in heat exchanger. When
installed parallel with a furnace, dampers or other means used to
control flow of air must prevent chilled air from entering furnace.
If dampers are manually operated, they must be equipped with a
means to prevent operation of either unit unless damper is in
full-heat or full-cool position.
°F °F
MAX 85°F MIN 55°F
A93042
B
A
C
K
A93043
12
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
If these furnaces are installed in an unconditioned space
where ambient temperatures may be 32°F or lower, freeze
protection measures must be taken.
Step 3—Hazardous Locations
When furnace is installed in a residential garage, it must be
installed so that burners and ignition sources are located a
minimum of 18 in. above floor. The furnace must be located
or protected to avoid physical damage by vehicles. When
furnace is installed in a public garage, airplane hangar, or
other building having a hazardous atmosphere, unit must be
installed in accordance with requirements of National Fire
Protection Association, Inc.

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. 12.) Install field-supplied,
corrosion-resistant 5/16-in. machine bolts and nuts.
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. 12.)
Holes in bottom closure panel may be used as guide locations.
A93058
A93044