Furnace Location Relative To Cooling Equipment; Location; Hazardous Locations; Installation - Carrier 58MCA Installation, Start-Up, And Operating Instructions Manual

This gas furnace may be used for construction heat provided
that:
-The furnace is permanently installed with all electrical
wiring, piping, venting and ducting installed according to
these installation instructions. A return air duct is provided,
sealed to the furnace casing, and terminated outside the space
containing the furnace. This prevents a negative pressure
condition as created by the circulating air blower, causing a
flame rollout and/or drawing combustion products into the
structure.
-The furnace is controlled by a thermostat. It may not be "hot
wired" to provide heat continuously to the structure without
thermostatic control.
-Clean outside air is provided for combustion. This is to
minimize the corrosive effects of adhesives, selaers and other
construction materials. It also prevents the entrainment of
drywall dust into combustion air, which can cause fouling and
plugging of furnace components.
-The temperature of the return air to the furnace is no less
than 55°F, with no evening setback or shutdown. The use of
the furnace while the structure is under construction is
deemed to be intermittent operation per our installation
instructions.
-The air temperature rise is within the rated rise range on the
furnace rating plate, and the firing rate has been set to the
nameplate value.
-The filters used to clean the circulating air during the
construction process must be either changed or thoroughly
cleaned prior to occupancy.
-The furnace, ductwork and filters are cleaned as necessary to
remove drywall dust and construction debris from all HVAC
system components after construction is completed.
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. (See Fig. 14.)
FRONT
BACK
FRONT
Fig. 14—Prohibit Installation on Back
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 shall be adequate to 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.
If these furnaces are installed in an unconditioned space
where ambient temperatures may be 32°F or lower, freeze
protection measures must be taken. (See Fig. 15.)
Step 3—Hazardous Locations
When the furnace is installed in a residential garage, the
burners and ignition sources must be located at least 18 in.
above the floor. The furnace must be located or protected to
avoid physical damage by vehicles. When the furnace is
installed in a public garage, airplane hangar, or other building
having a hazardous atmosphere, the furnace must be installed
in accordance with the NFGC or NSCNGPIC. (See Fig. 16.)
B
A
C
K
A93043
Step 1—Leveling Legs (If Desired)
When furnace is used in upflow position with side inlet(s), leveling
legs may be desired. (See Fig. 17.) 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. 17.)
Holes in bottom closure panel may be used as guide locations.
13
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
Fig. 15—Freeze Protection
18-IN. MINIMUM
TO BURNERS
Fig. 16—Installation in a Garage

INSTALLATION

A93058
A93044