Product Data - Carrier

028 units, and one size for all others].)
The contractor can order and
install the roof curb early in the construction
stage, before decisions on
size requirements are made.
All units feature roll-formed baserail
design with forklift slots on 3 sides
and rigging holes for easier maneuvering.
The standard 48TJ004-006
units have operating weights under
500 lb and durable packaging
protects all units during shipment
and storage.
The units can be easily converted
from a vertical to a horizontal discharge
configuration either by interchanging
the panels supplied with the
unit (004-014) or by using one of
the horizontal supply/return curbs or
the horizontal adapter (016-028).
Convenient duct openings in the
48TJ016-028 unit basepans permit
side-by-side or concentric duct connections
(see Application data section on
page 64) without requiring internal
unit modification.
The non-corrosive sloped condensate
pan permits either an external
horizontal side condensate drain (outside
the roof curb) or an internal
vertical bottom drain (inside the roof
curb). Both options require an external,
field-supplied P-trap. Also, the condenser
coil grille (available on the
004-014 units as a field-installed accessory
or a factory-installed option)
provides a metal plate as an alternate
location for the field-supplied disconnect,
if desired.
The 48TJ units were designed with
service technicians in mind. The
single-row condenser coils on the
48TJ004-006 and 008 units simplify
the cleaning process. The efficient
in-shot burners and all ignition components
are contained in an easily
removable, compact assembly.
The 48TJ004-014 units also have
a standard filter access panel, which
permits tool-less filter changes, even
on units with horizontal economizers.
Integrated gas unit controller
(IGC) (004-014 only)
All ignition components are contained
in the compact IGC which is easily
accessible for servicing. The IGC control
board, designed and manufactured
exclusively for Carrier rooftop
units, provides built-in diagnostic
capability. An LED (light-emitting diode)
simplifies troubleshooting by
2
providing visual fault notification and
system status confirmation.
The IGC also contains an exclusive
anti-cycle protection for gas heat
operation. After 4 continuous cycles
on the unit high-temperature limit
switch, the gas heat operation is disabled,
and an error code is issued.
This feature greatly improves reliability
of the rooftop unit.
The IGC also contains burner control
logic for accurate and dependable
gas ignition. The LED is visible
without removing the unit control box
access panel. This LED faultnotification
system reduces service
person troubleshooting time and minimizes
service costs. The IGC also
maximizes heating efficiency by controlling
evaporator-fan on and off
delays.
Simple electrical connections
Terminal boards, located in the base
unit control box, facilitate connections
to room thermostat, outdoor thermostat(s),
and economizer. Service
panels are quickly removed, permitting
easy servicing.
Thru-the-bottom service connection
capability (004-014) and thru-thecurb
service connections (016-028)
allow power and control wiring to
be routed through unit basepan
(004-014 units) or curb (016-028
units), minimizing roof penetrations.
Both power and control connections
are made on the same side of
the unit to simplify installation.
In addition, color-coded wires permit
easy tracing and diagnostics.
Table of contents
Proven compressor reliability
Design techniques feature computerprogrammed
balance between
compressor, condenser, and evaporator.
Carrier-specified hermetic
(004-014 units) and semi-hermetic
(016-028 units) compressors are
equipped with compressor overcurrent
and overtemperature protection to
ensure dependability. Crankcase heaters
(016-028 units) prevent refrigerant
dilution of oil during off cycles and
ensure proper lubrication at start-up
to prolong compressor life. Crankcase
heaters are not necessary on 004-
014 units due to high-side crankcase
design (007,014) and low refrigerant
charge levels (004-014).
The 48TJ016 unit (with factorysupplied
unloading) is equipped with a
thermostatic expansion valve to precisely
adjust refrigerant flow during
Stage 1 (unloaded) operation. All
other 48TJ units have Carrier’s exclusive
Acutrol metering device which
precisely controls refrigerant flow,
preventing slugging and flood-back,
while maintaining optimum unit
performance.
Durable, dependable
construction
Designed for durability in any
climate, the weather-resistant cabinets
are constructed of galvanized
steel and bonderized, and all exterior
panels are coated with a prepainted
baked enamel finish. The paint finish
is non-chalking, and is capable of
withstanding Federal test method
Standard No. 141 (Method 6061)
500-hour salt spray test. All internal
Page
Features/Benefits .........................................1-4
Model Number Nomenclature .................................4
ARI Capacity Ratings. ......................................5,6
Physical Data ...........................................7-12
Options and Accessories ...................................13-15
Base Unit Dimensions ....................................16-20
Accessory Dimensions ....................................21-24
Selection Procedure ........................................24
Performance Data .......................................25-52
Electrical Data ..........................................53,54
Typical Piping and Wiring ..................................55,56
Typical Wiring Schematics .................................57,58
Controls ..............................................59-63
Application Data ........................................64,65
Guide Specifications ......................................66-72