When a furnace is installed so that supply ducts carry air circulated
by the furnace to areas outside the space containing the furnace,
return air must also be handled by ducts sealed to furnace casing.
The ducts terminate outside the space containing the furnace to
ensure a negative pressure condition will not occur within equip-
ment room or space.
FIRE, INJURY OR DEATH HAZARD
Failure to follow this warning could result in fire, personal
injury, or death.
Do not install furnace on its back. (See Fig. 14.) Safety
control operation will be adversely affected. Never connect
return-air ducts to back of furnace.
UNIT DAMAGE HAZARD
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, sealers 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.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in minor property or
unit damage.
If this furnace is installed in an unconditioned space where
the ambient temperatures may be 32°F or lower, freeze
protection measures must be taken. (See Fig. 15.)
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
the damper is in full-heat or full-cool position.
Fig. 13—Proper Condensate Drainage
A02146
UPFLOW OR DOWNFLOW
HORIZONTAL
FRONT
LEVEL (0
″
)
TO
1
⁄
2
″
MAX
MIN
1
⁄
4
″
TO
1
⁄
2
″
MAX
FRONT
Fig. 14—Prohibit Installation on Back
A93043
FRONT
BACK
FRONT
B
A
C
K
Fig. 15—Freeze Protection
A93058
32
°
F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
14
