2
Follow all safety codes. Installation must be in compliance with
local and national building codes. Wear safety glasses, protective
clothing, and work gloves. Have fire extinguisher available. Read
these instructions thoroughly and follow all warnings or cautions
included in literature and attached to the unit.
Recognize safety information. This is the safety--alert symbol
.
When you see this symbol on the unit and in instructions or manuals,
be alert to the potential for personal injury. Understand these signal
words: DANGER, WARNING, and CAUTION. These words are
used with the safety--alert symbol. DANGER identifies the most se-
rious hazards which
will
result in severe personal injury or death.
WARNING signifies hazards which
could
result in personal injury
or death. CAUTION is used to identify unsafe practices which
may
result in minor personal injury or product and property damage.
NOTE is used to highlight suggestions which
will
result in en-
hanced installation, reliability, or operation.
Always install furnace to operate within the intended temperature
rise range with a duct system which has an external static pressure
within the allowable range, as specified in “Indoor Airflow Adjust-
ments” section of these instructions. See furnace rating plate.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Before installing or servicing system, always turn off main
power to system. There may be more than one disconnect
switch. Turn off accessory heater power switch if applicable.
!
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could result in personal injury
or equipment damage.
Puron (R--410A) systems operate at higher pressures than
standard R--22 systems. DO NOT use R--22 service
equipment or components on Puron (R--410A) equipment.
Ensure service equipment is rated for Puron (R--410A).
WARNING
!
INTRODUCTION
The 48DU packaged unit is a fully self--contained combination
Category I gas heating/electric air conditioner designed for outdoor
installation (See Fig. 1). Standard units are shipped in a
horizontal--discharge configuration for installation on a
ground--level slab or directly on the ground if local codes permit.
Standard units can be converted to downflow (vertical) discharge
configurations for rooftop applications.
Models with an N in the fifth position of the model number are
dedicated Low NOx units designed for California installations.
These models meet the California maximum oxides of nitrogen
(NOx) emissions requirements of 40 nanograms/joule or less as
shipped from the factory and must be installed in California Air
Quality Management Districts or any other regions in North
America where a Low NOx rule exists.
NOTE
: Low NOx requirements apply only to natural gas
installations.
RECEIVING AND INSTALLATION
Step 1—Check Equipment
IDENTIFY UNIT
The unit model number and serial number are printed on the unit
informative plate. Check this information against shipping papers.
INSPECT SHIPMENT
Inspect for shipping damage while unit is still on shipping pallet. If
unit appears to be damaged or is torn loose from its anchorage, have
it examined by transportation inspectors before removal. Forward
claim papers directly to transportation company. Manufacturer is
not responsible for any damage incurred in transit. Check all items
against shipping list. Immediately notify the nearest Carrier office
if any item is missing. To prevent loss or damage, leave all parts in
original packages until installation.
Step 2—Provide Unit Support
For hurricane tie downs, contact distributor for details and PE
(Professional Engineering) Certificate, if required.
ROOF CURB
Install accessory roof curb in accordance with instructions shipped
with curb (See Fig. 4). Install insulation, cant strips, roofing, and
flashing. Ductwork must be attached to curb.
IMPORTANT
: The gasketing of the unit to the roof curb is critical
for a water tight seal. Install gasketing material supplied with the
roof curb. Improperly applied gasketing also can result in air leaks
and poor unit performance.
Curb should be level to within 1/4 in. (See Fig. 2). This is necessary
for unit drain to function properly. Refer to accessory roof curb
installation instructions for additional information as required.
A
B
C
MAXIMUM ALLOWABLE
DIFFERENCE (in.)
A-B
B-C
A-C
1/4
1/4
1/4
C99065
Fig. 2 -- Unit Leveling Tolerances
SLAB MOUNT
Place the unit on a solid, level concrete pad that is a minimum of 4
in. thick with 2 in. above grade. The slab should extend
approximately 2 in. beyond the casing on all 4 sides of the unit (See
Fig. 3). Do not secure the unit to the slab
except
when required by
local codes.
OPTIONAL
RETURN
AIR
OPENING
OPTIONAL
SUPPLY
AIR
OPENING
EVAP. COIL
COND. COIL
2"
C99096
Fig. 3 -- Slab Mounting Detail
GROUND MOUNT
The unit may be installed either on a slab or placed directly on the
ground if local codes permit. Place the unit on level ground prepared
with gravel for condensate discharge.
48D
U