Carrier WeatherMaster 48HC04 Series Installation and user guide

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480156-01 Printed in U.S.A. Form 48HC-4-14-03SM Rev. C Pg 1 10-19 Replaces: 48HC-4-14-02SM
Service and Maintenance Instructions
CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 2
UNIT ARRANGEMENT AND ACCESS. . . . . . . . . . . . . 3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Seasonal Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . 3
RETURN AIR FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . 3
Outside Air Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Economizer Inlet Air Screen . . . . . . . . . . . . . . . . . . . . 4
Manual Outside Air Hood Screen . . . . . . . . . . . . . . . . 4
SUPPLY FAN (BLOWER) SECTION . . . . . . . . . . . . . . 4
Supply Fan (Direct-Drive) . . . . . . . . . . . . . . . . . . . . . . 4
Supply Fan (Belt-Drive) . . . . . . . . . . . . . . . . . . . . . . . . 6
Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STAGED AIR VOLUME CONTROL — 2 SPEED FAN
WITH VARIABLE FREQUENCY DRIVE (VFD) . . . . 7
Staged Air Volume (SAV) Indoor Fan Speed
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Identifying Factory Option . . . . . . . . . . . . . . . . . . . . . 7
Unit Installation with SAV Option . . . . . . . . . . . . . . . . 8
ADDITIONAL VARIABLE FREQUENCY DRIVE (VFD)
INSTALLATION AND TROUBLESHOOTING . . . . . 8
MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Replacing the Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Changing Fan Wheel Speed . . . . . . . . . . . . . . . . . . . . 9
REMOTE VFD KEYPAD REFERENCE . . . . . . . . . . . . 9
COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Condenser Coil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Condenser Coil Maintenance and Cleaning
Recommendation. . . . . . . . . . . . . . . . . . . . . . . . . . 12
Evaporator Coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
THERMOSTATIC EXPANSION VALVE (TXV) . . . . . . 13
TXV Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Replacing TXV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Refrigerant System Pressure Access Ports . . . . . . 14
PURON® (R-410A) REFRIGERANT. . . . . . . . . . . . . . 15
Refrigerant Charge. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
COOLING CHARGING CHARTS . . . . . . . . . . . . . . . . 15
COMPRESSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Replacing Compressor . . . . . . . . . . . . . . . . . . . . . . . 18
Compressor Rotation . . . . . . . . . . . . . . . . . . . . . . . . 18
Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Condenser-Fan Adjustment . . . . . . . . . . . . . . . . . . . 18
CONVENIENCE OUTLETS . . . . . . . . . . . . . . . . . . . . . 20
SMOKE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . 21
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Smoke Detector Sensor . . . . . . . . . . . . . . . . . . . . . . .21
Smoke Detector Locations. . . . . . . . . . . . . . . . . . . . .22
Completing Installation of Return Air Smoke
Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
FIOP Smoke Detector Wiring and Response . . . . . .23
SENSOR AND CONTROLLER TESTS . . . . . . . . . . . .24
Sensor Alarm Test . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Controller Alarm Test . . . . . . . . . . . . . . . . . . . . . . . . .24
Dirty Controller Test . . . . . . . . . . . . . . . . . . . . . . . . . .24
Dirty Sensor Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Dirty Sensor Test Procedure . . . . . . . . . . . . . . . . . . .25
Changing the Dirt Sensor Test . . . . . . . . . . . . . . . . .25
Remote Station Test . . . . . . . . . . . . . . . . . . . . . . . . . .25
SD-TRK4 Remote Alarm Test Procedure . . . . . . . . .25
Remote Test/Reset Station Dirty Sensor Test . . . . .25
Dirty Sensor Test Using an SD-TRK4 . . . . . . . . . . . .26
Detector Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
PROTECTIVE DEVICES . . . . . . . . . . . . . . . . . . . . . . .27
Compressor Protection . . . . . . . . . . . . . . . . . . . . . . .27
Relief Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Control Circuit, 24-V . . . . . . . . . . . . . . . . . . . . . . . . . .27
GAS HEATING SYSTEM . . . . . . . . . . . . . . . . . . . . . . .28
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Fuel Types and Pressures . . . . . . . . . . . . . . . . . . . . .28
Flue Gas Passageways . . . . . . . . . . . . . . . . . . . . . . .29
Combustion-Air Blower . . . . . . . . . . . . . . . . . . . . . . .29
Burners and Igniters. . . . . . . . . . . . . . . . . . . . . . . . . .31
Removing the Heat Exchanger . . . . . . . . . . . . . . . . .32
Burner Ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Orifice Replacement . . . . . . . . . . . . . . . . . . . . . . . . . .33
Troubleshooting Heating System . . . . . . . . . . . . . . .42
PremierLink™ Control . . . . . . . . . . . . . . . . . . . . . . . .43
RTU Open Control System. . . . . . . . . . . . . . . . . . . . .43
ECONOMIZER SYSTEMS . . . . . . . . . . . . . . . . . . . . . .43
EconoMi$er IV Standard Sensors . . . . . . . . . . . . . . .49
EconoMi$er IV Control Modes . . . . . . . . . . . . . . . . . .49
EconoMi$er IV Preparation . . . . . . . . . . . . . . . . . . . .53
Differential Enthalpy. . . . . . . . . . . . . . . . . . . . . . . . . .53
Single Enthalpy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
DCV (Demand Controlled Ventilation) and Power
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
DCV Minimum and Maximum Position . . . . . . . . . . .53
Supply-Air Sensor Input. . . . . . . . . . . . . . . . . . . . . . .53
EconoMi$er IV Troubleshooting Completion. . . . . .54
EconoMi$er® X (Factory Option) . . . . . . . . . . . . . . .54
PRE-START-UP/START-UP . . . . . . . . . . . . . . . . . . . .68
WeatherMaster®
48HC04-14
Single Package Rooftop Gas Heat/Electric Cooling Unit
with Puron®(R-410A) Refrigerant

2
START-UP, GENERAL . . . . . . . . . . . . . . . . . . . . . . . . 68
Unit Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Additional Installation/Inspection . . . . . . . . . . . . . . . 68
Gas Piping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Return-Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Outdoor-Air Inlet Screens . . . . . . . . . . . . . . . . . . . . . 69
Compressor Mounting . . . . . . . . . . . . . . . . . . . . . . . . 69
Internal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Refrigerant Service Ports . . . . . . . . . . . . . . . . . . . . . 69
Compressor Rotation. . . . . . . . . . . . . . . . . . . . . . . . . 69
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Main Burners. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Ventilation (Continuous Fan) . . . . . . . . . . . . . . . . . . 70
START-UP, PREMIERLINK CONTROLS . . . . . . . . . . 70
Perform System Check-Out. . . . . . . . . . . . . . . . . . . . 70
START-UP, RTU-OPEN CONTROLS . . . . . . . . . . . . . 70
FASTENER TORQUE VALUES . . . . . . . . . . . . . . . . . 70
APPENDIX A —MODEL NUMBER
NOMENCLATURE. . . . . . . . . . . . . . . . . . . . . . . . . . 71
APPENDIX B — PHYSICAL DATA. . . . . . . . . . . . . . . 72
APPENDIX C — FAN PERFORMANCE . . . . . . . . . . . 78
APPENDIX D — WIRING DIAGRAMS . . . . . . . . . . . . 94
APPENDIX E — MOTORMASTER SENSOR
LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . CL-1
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified service personnel should install, repair, or
service air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of
cleaning coils and filters and replacing filters. All other operations
should be performed by trained service personnel. When working
on air-conditioning equipment, observe precautions in the litera-
ture, tags and labels attached to the unit, and other safety precau-
tions that may apply.
Follow all safety codes, including ANSI (American National Stan-
dards Institute) Z223.1. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.
It is important to recognize safety information. This is the safety-
alert symbol . When you see this symbol on the unit and in in-
structions or manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious 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 enhanced installation, reliability,
or operation.
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Units with convenience outlet circuits may use multiple
disconnects. Check convenience outlet for power status before
opening unit for service. Locate its disconnect switch, if
appropriate, and open it. Lock-out and tag-out this switch, if
necessary.
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron®(R-410A) refrigerant systems operate at higher pres-
sures than standard R-22 systems. Do not use R-22 service
equipment or components on Puron refrigerant equipment.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Disconnect gas piping from unit when pressure testing at
pressure greater than 0.5 psig (3450 Pa). Pressures greater than
0.5 psig will cause gas valve damage resulting in hazardous
condition. If gas valve is subjected to pressure greater than
0.5 psig, it must be replaced before use. When pressure testing
field-supplied gas piping at pressures of 0.5 psig or less, a unit
connected to such piping must be isolated by closing the
manual gas valve(s).
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use air or gases containing oxygen for leak testing or for
operating refrigerant compressors. Pressurized mixtures of air
or gases containing oxygen can lead to an explosion.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use non-certified refrigerants in this product. Non-certi-
fied refrigerants could contain contaminates that could lead to
unsafe operating conditions. Use ONLY refrigerants that con-
form to AHRI Standard 700.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit perfor-
mance or unit shutdown.
High velocity water from a pressure washer, garden hose, or
compressed air should never be used to clean a coil. The force
of the water or air jet will bend the fin edges and increase air-
side pressure drop.

3
UNIT ARRANGEMENT AND ACCESS
General
Figures 1 and 2 show general unit arrangement and access
locations.
Fig. 1 — Typical Access Panel Locations
Fig. 2 — Blower Access Panel Location
MAINTENANCE
Routine Maintenance
These items should be part of a routine maintenance program, to
be checked every month or two, until a specific schedule for each
can be identified for this installation.
Quarterly Inspection (and 30 days after initial start)
• Return air filter replacement
• Outdoor hood inlet filters cleaned
• Belt tension checked
• Belt condition checked
• Pulley alignment checked
• Fan shaft bearing locking collar tightness checked
• Condenser coil cleanliness checked
• Condensate drain checked
Seasonal Maintenance
These items should be checked at the beginning of each season (or
more often if local conditions and usage patterns dictate).
AIR CONDITIONING
• Condenser fan motor mounting bolts tightness
• Compressor mounting bolts
• Condenser fan blade positioning
• Control box cleanliness and wiring condition
• Wire terminal tightness
• Refrigerant charge level
• Evaporator coil cleaning
• Evaporator blower motor amperage
HEATING
• Heat exchanger flue passageways cleanliness
• Gas burner condition
• Gas manifold pressure
• Heating temperature rise
ECONOMIZER OR OUTSIDE AIR DAMPER
• Inlet filters condition
• Check damper travel (economizer)
• Check gear and dampers for debris and dirt
AIR FILTERS AND SCREENS
Each unit is equipped with return air filters. If the unit has an econ-
omizer, it will also have an outside air screen. If a manual outside
air damper is added, an inlet air screen will also be present.
Each of these filters and screens will need to be periodically re-
placed or cleaned.
RETURN AIR FILTERS
Return air filters are disposable fiberglass media type. Access to
the filters is through the small lift-out panel located on the rear
side of the unit, above the evaporator/return air access panel. (See
Fig. 1.)
To remove the filters:
1. Grasp the bottom flange of the upper panel.
2. Lift up and swing the bottom out until the panel disen-
gages and pulls out.
3. Reach inside and extract the filters from the filter rack.
4. Replace these filters as required with similar replacement
filters of same size.
IMPORTANT: OPERATIONAL TEST ALERT
Failure to follow this ALERT can result in an unnecessary
evacuation of the facility.
Pressing the controller’s test/reset switch for longer than
seven seconds will put the duct detector into the alarm state
and activate all automatic alarm responses.
IMPORTANT: Lockout/tag-out is a term used when elec-
trical power switches are physically locked preventing
power to the unit. A placard is placed on the power switch
alerting service personnel that the power is disconnected.
FILTER ACCESS PANEL
OUTDOOR-AIR OPENING AND
INDOOR COIL ACCESS PANEL
COMPRESSOR
ACCESS PANEL (04-07 only)
BLOWER
ACCESS
PANEL
CONTROL BOX
COMPRESSOR
(08-09 only)
FLUE OPENING
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in premature wear
and damage to equipment.
DO NOT OPERATE THE UNIT WITHOUT THE RETURN
AIR FILTERS IN PLACE.
Dirt and debris can collect on heat exchangers and coils possi-
bly resulting in a small fire. Dirt buildup on components can
cause excessive current used resulting in motor failure.

4
To re-install the access panel:
1. Slide the top of the panel up under the unit top panel.
2. Slide the bottom into the side channels.
3. Push the bottom flange down until it contacts the top of
the lower panel (or economizer top).
Outside Air Hood
Outside air hood inlet screens are permanent aluminum-mesh type
filters. Check these for cleanliness. Remove the screens when
cleaning is required. Clean by washing with hot low-pressure wa-
ter and soft detergent and replace all screens before restarting the
unit. Observe the flow direction arrows on the side of each filter
frame.
Economizer Inlet Air Screen
This air screen is retained by filter clips under the top edge of the
hood. (See Fig. 3.)
Fig. 3 — Filter Installation
To remove the filter, open the filter clips. Re-install the filter by
placing the frame in its track, then closing the filter clips.
Manual Outside Air Hood Screen
This inlet screen is secured by a retainer angle across the top edge
of the hood. (See Fig. 4.)
Fig. 4 — Screens Installed on Outdoor-Air Hood
(Sizes 71/2to 81/2Tons Shown)
To remove the screen, loosen the screws in the top retainer and slip
the retainer up until the filter can be removed. Re-install by plac-
ing the frame in its track, rotating the retainer back down, and
tightening all screws.
SUPPLY FAN (BLOWER) SECTION
Supply Fan (Direct-Drive)
For unit sizes 04, 05, and 06, a direct-drive forward-curved cen-
trifugal blower wheel is an available option. The motor has taps to
provide the servicer with the selection of one of five motor torque/
speed ranges to best match wheel performance with attached duct
system. See Fig. 5 and 6.
Fig. 5 — Direct-Drive Supply Fan Assembly
Fig. 6 — ECM Motor Connectors
ECM MOTOR
The direct-drive motor is an X13 Electronically Commutated Mo-
tor (ECM). An ECM motor contains electronic circuitry used to
convert single-phase line AC voltage into 3-phase DC voltage to
power the motor circuit. The motor circuit is a DC brushless de-
sign with a permanent magnet rotor. On the X13 ECM Motor
17 1/4”
DIVIDER
BAROMETRIC
RELIEF
CLEANABLE
ALUMINUM
FILTER FILTER
HOOD
FILTER
CLIP
OUTSIDE
AIR
SCREWS
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Before performing service or maintenance operations on unit,
LOCKOUT/TAGOUT the main power switch to unit. Electri-
cal shock and rotating equipment could cause severe injury.
ECM Motor
Motor Plug Position
(95° from vertical)
95° ECM Power
Transformer
(460, 575v)
L2
YEL
Gnd
GRN/YEL
L1
BLU
C
12345
LGN
Motor
Power
Connections
Speed
Taps
Com
BRN
VIO
Default Connection

5
design, the electronic circuitry is integral to the motor assembly
and cannot be serviced or replaced separately.
The 208/230-v units use a 230-v motor. 460-v units use a 230-v
motor with a stepdown transformer (mounted on the end of the fan
housing, see Fig. 5). 575-v units use a 460-v motor with an auto-
transformer. Motor power voltage is connected to motor terminals
L and N (see Fig. 6 and Fig. 7); ground is connected at terminal G.
The motor power voltage is ALWAYS present; it is not switched
off by a motor contactor.
EVALUATING MOTOR SPEED
The X13 ECM Motor uses a constant torque motor design. The
motor speed is adjusted by the motor control circuitry to maintain
the programmed shaft torque. Consequently, there is no specific
speed value assigned to each control tap setting. At the Position 5
tap, the motor speed is approximately 1050 RPM (17.5 r/s), but
varies depending on fan wheel loading.
SELECTING SPEED TAP
The five communication terminals are each programmed to pro-
vide a different motor torque output. See Table 1. Factory default
tap selection is Position 1 for lowest torque/speed operation.
Table 1 — Motor Tap Programing (Percent of
Full-Load Torque)
NOTE: Factory Default: Tap 1 (VIO)
Selecting another speed:
1. Disconnect main power to the unit. Apply lockout/tag-out
procedures.
2. Remove the default motor signal lead (VIO) from
terminal 1 at the motor communications terminal.
3. Reconnect the motor signal lead to the desired speed
(terminals 1 through 5).
4. Connect main power to the unit.
MOTOR “ROCKING” ON START-UP
When the motor first starts, the rotor (and attached wheel) will
“rock” back and forth as the motor tests for rotational direction.
Once the correct rotational direction is determined by the motor
circuitry, the motor will ramp up to the specified speed. The
“rocking” is a normal operating characteristic of ECM motors.
Fig. 7 — Direct-Drive Supply Fan Assembly
48HC
UNIT SIZE TAP 1 TAP 2 TAP 3 TAP 4 TAP 5
04 32 38 45 50 100
05 46 58 61 69 100
06 73 82 85 90 100
460, 575-v Units
208/230-v Units

6
TROUBLESHOOTING THE ECM MOTOR
Troubleshooting the X13 ECM requires a voltmeter.
1. Disconnect main power to the unit.
2. Remove the motor power plug (including the control BRN
lead) and VIO control signal lead at the motor terminals.
3. Restore main unit power.
4. Check for proper line voltage at motor power leads BLK
(at L terminal) and YEL (at N terminal). See Table 2.
5. Using a jumper wire from unit control terminals R to G,
engage motor operation. Check for 24-v output at the
defrost board terminal IFO.
6. Check for proper control signal voltages of 22-v to 28-v at
motor signal leads VIO and BRN.
7. Disconnect unit main power. Apply lockout/tag-out
procedures.
8. Reconnect motor power and control signal leads at the
motor terminals.
9. Restore unit main power.
10. The motor should start and run. If the motor does not start,
remove the motor assembly. Replace the motor with one
that has the same part number. Do not substitute with an
alternate design motor, as the torque/speed programming
will not be the same as that on an original factory motor.
REPLACING THE X-13 ECM MOTOR
Before removing the ECM belly-band mounting ring from old
motor:
1. Measure the distance from base of the motor shaft to the
edge of the mounting ring.
2. Remove the motor mounting band and transfer it to the
replacement motor.
3. Position the mounting band at the same distance that was
measured in Step 1.
4. Hand-tighten mounting bolt only. Do not tighten securely
at this time.
5. Insert the motor shaft into the fan wheel hub.
6. Securely tighten the three motor mount arms to the support
cushions and torque the arm mounting screws to 60 in.-lb
(6.8 Nm).
7. Center the fan wheel in the fan housing. Tighten the fan
wheel hub setscrew and torque to 120 in.-lb (13.6 Nm).
8. Ensure the motor terminals are located at a position below
the 3 o’clock position. Tighten the motor belly-band bolt
and torque to 80 in.-lb (9.0 Nm).
Supply Fan (Belt-Drive)
The belt-drive supply fan system consists of a forward-curved
centrifugal blower wheel on a solid shaft with two concentric type
bearings, one on each side of the blower housing. A fixed-pitch
driven pulley is attached to the fan shaft and an adjustable-pitch
driver pulley is on the motor. The pulleys are connected using a V-
belt. (See Fig. 8.)
Fig. 8 — Typical Belt Drive Motor Mounting
Belt
Check the belt condition and tension quarterly. Inspect the belt for
signs of cracking, fraying, or glazing along the inside surfaces.
Check belt tension by using a spring-force tool, such as Brown-
ing’s “Belt Tension Checker” (P/N: 1302546 or equivalent tool);
tension should be 6 lb at a 5/8-in. (1.6 cm) deflection when mea-
sured at the centerline of the belt span. This point is at the center of
the belt when measuring the distance between the motor shaft and
the blower shaft.
NOTE: Without the spring-tension tool, place a straight edge
across the belt surface at the pulleys, then push down on the belt at
mid-span using one finger until a 1/2-in. (1.3 cm) deflection is
reached. See Fig. 9.
Adjust belt tension by loosening the motor mounting plate front
and rear bolts and sliding the plate toward the fan (to reduce ten-
sion) or away from fan (to increase tension). Ensure the blower
shaft and the motor shaft are parallel to each other (pulleys
aligned). When finished, tighten all bolts and torque to 65 to
70 in.-lb (7.4 to 7.9 Nm).
Fig. 9 — Checking Blower Motor Belt Tension
REPLACING THE BELT
NOTE: Use a belt with same section type or similar size. Do not
substitute a FHP-type belt. When installing the new belt, do not
use a tool (screwdriver or pry-bar) to force the belt over the pulley
flanges as this will stress the belt and cause a reduction in belt life.
Damage to the pulley can also occur.
Use the following steps to replace the V-belt. See Fig. 8.
1. Loosen the front and rear motor mounting plate bolts.
2. Push the motor and its mounting plate towards the blower
housing as close as possible to reduce the center distance
between fan shaft and motor shaft.
Table 2 — Motor Test Volts
UNIT VOLTAGE MOTOR VOLTAGE MIN-MAX VOLTS
208/230 230 190-250
460 230 210-250
575 460 420-500
BLOWER PULLEY
V --- B E LT
MOTOR
PULLEY
MOTOR MOUNTING
PLATE
MOTOR
MOUNTING
BOLTS (4)
BROWNING BELT
TENSION CHECKER
STRAIGHTEDGE
1/2”
(1.3 cm)
BELT
DEFLECTION

7
3. Remove the belt by gently lifting the old belt over one of
the pulleys.
4. Install the new belt by gently sliding the belt over both
pulleys and then sliding the motor and plate away from the
fan housing until proper tension is achieved.
5. Check the alignment of the pulleys, adjust if necessary.
6. Tighten all bolts and torque to 65 to 70 in.-lb (7.4 to
7.9 Nm).
7. Check the tension after a few hours of runtime and read-
just as required.
ADJUSTABLE-PITCH PULLEY ON MOTOR
The motor pulley is an adjustable-pitch type that allows a servicer
to implement changes in the fan wheel speed to match as-installed
ductwork systems. The pulley consists of a fixed flange side that
faces the motor (secured to the motor shaft) and a movable flange
side that can be rotated around the fixed flange side that increases
or reduces the pitch diameter of this driver pulley. (See Fig. 10.)
Fig. 10 — Supply-Fan Pulley Adjustment
As the pitch diameter is changed by adjusting the position of the
movable flange, the centerline on this pulley shifts laterally (along
the motor shaft). This creates a requirement for a realignment of
the pulleys after any adjustment of the movable flange. Reset the
belt tension after each realignment.
Inspect the condition of the motor pulley for signs of wear. Glaz-
ing of the belt contact surfaces and erosion on these surfaces are
signs of improper belt tension and/or belt slippage. Replace pulley
if wear is excessive.
CHANGING THE FAN SPEED:
1. Shut off unit power supply. Use proper lockout/tag-out
procedures.
2. Loosen belt by loosening fan motor mounting nuts. (See
Fig. 8.)
3. Loosen movable pulley flange setscrew. (See Fig. 10.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed the maximum specified speed.
5. Set movable flange at nearest keyway of pulley hub.
Tighten setscrew and torque to 65 to 70 in.-lb (7.4 to
7.9 Nm).
ALIGNING BLOWER AND MOTOR PULLEYS:
1. Loosen blower pulley setscrews.
2. Slide blower pulley along blower shaft. Make angular
alignment by loosening motor mounting plate front and
rear bolts.
3. Tighten blower pulley setscrews and motor mounting
bolts. Torque bolts to 65 to 70 in.-lb (7.4 to 7.9 Nm).
4. Recheck belt tension.
BEARINGS
The fan system uses bearings featuring concentric split locking
collars. A Torx T-25 socket head cap screw is used to tighten the
locking collars. Tighten the locking collar by holding it tightly
against the inner race of the bearing. Tighten the socket head cap
screw. Torque cap screw to 65 to 70 in.-lb (7.4 to 7.9 Nm). See
Fig. 11. Check the condition of the motor pulley for signs of wear.
Glazing of the belt contact surfaces and erosion on these surfaces
are signs of improper belt tension and/or belt slippage. Pulley re-
placement may be necessary.
Fig. 11 — Tightening Locking Collar
STAGED AIR VOLUME CONTROL — 2 SPEED
FAN WITH VARIABLE FREQUENCY DRIVE (VFD)
Staged Air Volume (SAV) Indoor Fan Speed
System
The Staged Air Volume (SAV) system utilizes a fan speed control
board and Variable Frequency Drive (VFD) to automatically ad-
just the indoor fan motor speed in sequence with the unit’s ventila-
tion, cooling, and heating operation. Per ASHRAE 90.1 2010
standard section 6.4.3.10.b, during the first stage of cooling opera-
tion the SAV system will adjust the fan motor to provide two-
thirds (2/3) of the design airflow rate for the unit. When the call for
the second stage of cooling is required, the SAV system will allow
the design airflow rate for the unit established (100%). During the
heating mode, the SAV system will allow total design airflow rate
(100%) operation. During ventilation mode, the SAV system will
operate the fan motor at 2/3speed.
Identifying Factory Option
This supplement only applies to units that meet the criteria de-
tailed in Table 3. If the unit does not meet that criteria, discard this
document.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in premature wear
and damage to equipment.
Do not use a screwdriver or a pry bar to place the new V-belt in
the pulley groove. This can cause stress on the V-belt and the
pulley resulting in premature wear on the V-belt and damage
to the pulley.
STRAIGHT EDGE
MUST BE PARALLEL
WITH BELT
SETSCREWS
MOTOR AND
FANSHAFTS
MUST BE
PARALLEL
FIXED FLANGE
MOVABLE
FLANGE
SINGLE - GROOVE
FAN PULLEY
MOTOR PULLEY
T --- 2 5 T O R X S O C K E T
HEAD CAP SCREW
LOCKING COLLAR

8
NOTE: See Appendix A for an example of Model Number Nomenclature.
Unit Installation with SAV Option
48HC ROOFTOP
Refer to the base unit installation instructions for standard required
operating and service clearances.
See “Variable Frequency Drive (VFD) Installation, Setup and
Troubleshooting Supplement” for wiring schematics and perfor-
mance charts and configuration.
See Fig. 12-14 for locations of the Variable Frequency Drive
(VFD) as mounted on the various 48HC models.
Fig. 12 — VFD Location for sizes 07-09
Fig. 13 — VFD Location for size 12
Fig. 14 — VFD Location for size 14
ADDITIONAL VARIABLE FREQUENCY DRIVE
(VFD) INSTALLATION AND TROUBLESHOOTING
Additional installation, wiring, and troubleshooting information
for the Variable Frequency Drive can be found in the following
manual: “Variable Frequency Drive (VFD) Installation, Setup and
Troubleshooting Supplement.”
MOTOR
When replacing the motor, use the following steps. See Fig. 15.
Fig. 15 — Replacing Belt-Driven Motor
Replacing the Motor
Use the following steps to replace the belt-driven motor.
1. Turn off all electrical power to the unit. Use approved
lockout/tag-out procedures on all electrical power sources.
2. Remove cover on motor connection box.
3. Disconnect all electrical leads to the motor.
4. Loosen the two jack bolt jam nuts on the motor mounting
bracket.
5. Turn two jack bolts counterclockwise until motor assem-
bly moves closer to blower pulley.
6. Remove V-belt from blower pulley and motor pulley.
Table 3 — Model-Size / VFD Option Indicator
MODEL / SIZES POSITION IN MODEL
NUMBER
VFD FIOP
INDICATOR
48HC / 07-14 17 G, J
IMPORTANT: The Remote VFD Keypad is a field-
installed option. It is not included as part of the factory-
installed VFD option.
VARIABLE
FREQUENCY
DRIVE (VFD)
VARIABLE
FREQUENCY
DRIVE (VFD)
VARIABLE
FREQUENCY
DRIVE (VFD)
BLOWER PULLEY
V-BELT
MOTOR PULLEY
MOTOR
MOTOR MOUNTING
BRACKET BOLTS (4)
MOTOR MOUNTING
BRACKET (2)
JACK BOLT JAM NUT (2)
JACK BOLT (2)

9
7. Loosen the four mounting bracket bolts and lock washers.
8. Remove four bolts, four flat washers, four lock washers
and four nuts attaching the motor mounting plate to the
unit. Discard all lock washers.
9. Remove motor and motor mounting bracket from unit.
10. Remove four bolts, flat washers, lock washers and single
external-tooth lock washer attaching motor to the motor
mounting plate. Discard all lock washers and external-
tooth lock washer.
11. Lift motor from motor mounting plate and set aside.
12. Slide motor mounting band from old motor.
13. Slide motor mounting band onto new motor and set motor
onto the motor mounting plate.
14. Remove variable pitch pulley from old motor and attach it
to the new motor.
15. Inspect variable pitch pulley for cracks and wear. Replace
the pulley if necessary.
16. Secure the pulley to the motor by tightening the pulley set-
screw to the motor shaft.
17. Insert four bolts and flat washers through mounting holes
on the motor into holes on the motor mounting plate.
18. On one bolt, place a new external-tooth lock washer
between the motor and motor mounting band.
19. Ensure the teeth of the external-tooth lock washer make
contact with the painted base of the motor. This washer is
essential for properly grounding motor.
20. Install four new lock washers and four nuts on the bolts on
the bottom of the motor mounting plate.
NOTE: Do not tighten the mounting bolts at this time.
21. Set new motor and motor mounting bracket back onto the
unit. See Fig. 15.
22. Install four bolts, four flat washers, four new lock washers
and four nuts attaching the motor assembly to the unit.
NOTE: Do not tighten the mounting bolts at this time.
23. Install motor drive V-belt to motor pulley and blower
wheel pulley. See the CAUTION above.
24. Align the motor pulley and blower wheel pulley using a
straight edge. See Fig. 10.
25. Adjust the V-belt tension using adjustment tool.
26. Turn two jack bolts clockwise, moving the motor assembly
away from the blower pulley, increasing the V-belt tension.
27. Tighten the four bolts securing the motor mounting brack-
ets to the unit. Torque four bolts to 120 ± 12 in.-lb (14 ±1.4
Nm).
28. Remove cover on motor connection box.
29. Re-connect all electrical leads to the motor and replace the
connection box cover.
30. Re-connect all electrical power to the unit. Remove lock-
out tags on all electrical power sources.
31. Start unit and allow to run for a designated period.
32. Shut off unit and make any necessary adjustments to the V-
belt tension or the motor and blower wheel pulley alignment.
When replacing the motor, also replace the external-tooth lock
washer (star washer) under the motor mounting base; this is part of
the motor grounding system. Ensure the teeth on the lock washer
are in contact with the motor’s painted base. Tighten motor
mounting bolts to 120 ± 12 in.-lb.
Changing Fan Wheel Speed
Changing fan wheel speed by changing pulleys: The horsepower
rating of the belt is primarily dictated by the pitch diameter of the
smaller pulley in the drive system (typically the motor pulley in
these units). Do not install a replacement motor pulley with a
smaller pitch diameter than provided on the original factory pul-
ley. Change fan wheel speed by changing the fan pulley (larger
pitch diameter to reduce wheel speed, smaller pitch diameter to in-
crease wheel speed) or select a new system (both pulleys and
matching belt).
Before changing pulleys to increase fan wheel speed, check the
fan performance at the target speed and airflow rate to determine
new motor loading (bhp). Use the fan performance tables or use
the Packaged Rooftop Builder software program. Confirm that the
motor in this unit is capable of operating at the new operating con-
dition. Fan shaft loading increases dramatically as wheel speed is
increased.
To reduce vibration, replace the motor’s adjustable pitch pulley
with a fixed pitch pulley (after the final airflow balance adjust-
ment). This will reduce the amount of vibration generated by the
motor/belt-drive system.
REMOTE VFD KEYPAD REFERENCE
See Tables 4 and 5 for SRT unit VFD parameters.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in premature wear
and damage to equipment.
Do not use a screwdriver or a pry bar to place the new V-belt in
the pulley groove. This can cause stress on the V-belt and the
pulley resulting in premature wear on the V-belt and damage
to the pulley.

10
Table 4 — SRT Unit VFD Parameters — 48HC** 07-12
VFD
Part
Num ber
ABB PartNum ber Description
Motor
Part
Num ber
Voltag e
(9905)
Nom
Am ps
(9906)
Motor
Nom
Freq
(9907)
Nom RPM
(9908)
Nom
HP
(9909)
Const
Speed Sel
(1201)
Const
Speed 1
(1202)
Const
Speed 2
(1203)
Const
Speed 3
(1204)
Relay
Out3
(1403)
Max
Am ps
(2003)
Min
Freq
(2007)
Max
Freq
(2008)
Sw itch
Freq
(2606)
Start
Fcn
(2101)
Stop
Fcn
(2102)
Accel/
Decel
(2201)
Accel
(2202)
Decel
(2203)
H K30W A 352 A CH 550---U 0 ---0 1 2 A ---2 1.7HP230V H D 56FR233 230 5.860H z 1725 1.7DI2,340H z 60H z 60H z 16 FLT/
Alarm6.70H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 356 ACH550---U 0 ---0 6 A 9 ---4 1.7HP460V H D 56FR463 460 2.960H z 1725 1.7DI2,340H z 60H z 60H z 16 FLT/
Alarm3.30H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 360 A CH 550---U 0 ---0 3 A 9 ---6 1.7HP575V H D 56FR579 575 3.160H z 1725 1.7DI2,340H z 60H z 60H z 16 FLT/
Alarm3.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 352 A CH 550---U 0 ---0 1 2 A ---2 2.4HP230V HD56FE653 230 7.960H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm9.10H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 356 ACH550---U 0 ---0 6 A 9 ---4 2.4HP460V HD56FE653 460 3.660H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm4.10H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 360 A CH 550---U 0 ---0 3 A 9 ---6 2.4HP575V HD56FE577 575 3.860H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm4.40H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 352 ACH550---U 0 ---0 1 2 A ---2 2.9HP230V HD58FE654 230 9.260H z 1725 2.9DI2,340H z 60H z 60H z 16 FLT/
Alarm10.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
HK30W A356 A CH 550---U 0 ---0 6 A 9 ---4 2.9HP460V HD58FE654 460 4.260H z 1725 2.9DI2,340H z 60H z 60H z 16 FLT/
Alarm4.80H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 353 A CH 550---U 0 ---017A ---2 3.7 H P 230V H D 60FE656 230 11.760H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm13.50H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 357 ACH550---U 0 ---0 8 A 8 ---4 3.7HP460V H D 60FE656 460 5.460H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm6.20H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 361 ACH550---U 0 ---0 6 A 1 ---6 3.7HP575V H D 58FE577 575 4.960H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm5.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 354 A CH 550---U 0 ---024A ---2 5.3HP230V HD60FK658 230 13.660H z 1740 5.3DI2,340H z 60H z 60H z 16 FLT/
Alarm15.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 358 A CH 550---U 0 ---012A ---4 5.3HP460V HD60FK658 460 6.460H z 1740 5.3DI2,340H z 60H z 60H z 16 FLT/
Alarm7.40H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 362 ACH550---U 0 ---0 9 A 0 ---6 5.3 H P 575V H D 60FE576 575 6.060H z 1725 5.3DI2,340H z 60H z 60H z 16 FLT/
Alarm6.90H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec

11
Table 5 — SRT Unit VFD Parameters — 48HC** 14
VFD
Part
Num ber
ABB PartNum ber Description
Motor
Part
Num ber
Voltage
(9905)
Nom
Am ps
(9906)
Motor
Nom
Freq
(9907)
Nom RPM
(9908)
Nom
HP
(9909)
Const
Speed Sel
(1201)
Const
Speed 1
(1202)
Const
Speed 2
(1203)
Const
Speed 3
(1204)
Relay
Out3
(1403)
Max
Am ps
(2003)
Min
Freq
(2007)
Max
Freq
(2008)
Sw itch
Freq
(2606)
Start
Fcn
(2101)
Stop
Fcn
(2102)
A ccel/
Decel
(2201)
A ccel
(2202)
Decel
(2203)
H K30W A 352 A CH 550---U 0 ---012A ---2 2.4 H P 230V H D 56FE653 230 7.960H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm9.10H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 356 ACH550---U 0 ---0 6 A 9 ---2 2.4HP460V H D 56FE653 460 3.660H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm4.10H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 360 ACH550---U 0 ---0 3 A 9 ---6 2.4 H P 575V H D 56FE577 575 3.860H z 1725 2.4DI2,340H z 60H z 60H z 16 FLT/
Alarm4.40H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 352 ACH550---U 0 ---012A ---2 2.9HP230V H D 58FE654 230 9.260H z 1725 2.9DI2,340H z 60H z 60H z 16 FLT/
Alarm10.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 356 ACH550---U 0 ---0 6 A 9 ---4 2.9 H P 460V H D 58FE654 460 4.260H z 1725 2.9DI2,340H z 60H z 60H z 16 FLT/
Alarm4.80H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 353 ACH550---U 0 ---017A ---2 3.7HP230V H D 60FE656 230 11.760H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm13.50H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 357 A CH 550---U 0 ---08A8 ---4 3.7 H P 460V H D 60FE656 460 5.460H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm6.20H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 361 ACH550---U 0 ---06A 1---6 3.7 H P 575V H D 58FE577 575 4.960H z 1725 3.7DI2,340H z 60H z 60H z 16 FLT/
Alarm5.60H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 354 A CH 550---U 0 ---0 2 4 A ---2 5.0 H P 230V H D 60FL657 230 17.160H z 1760 5DI2,340H z 60H z 60H z 16 FLT/
Alarm19.70H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
HK30W A358 ACH550---U 0 ---0 1 2 A ---4 5.0HP460V H D 60FL657 460 8.660H z 1760 5DI2,340H z 60H z 60H z 16 FLT/
Alarm9.90H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec
H K30W A 362 ACH550---U 0 ---0 9 A 0 ---6 5.0HP575V H D 60FK577 575 7.660H z 1745 5DI2,340H z 60H z 60H z 16 FLT/
Alarm8.70H z 60H z 4kH z AutoRam p NotSel 30 sec 30 sec

12
COOLING
Condenser Coil
The condenser coil is fabricated with round tube copper hairpins
and plate fins of various materials and/or coatings (see Model
Number Format in Appendix A to identify the materials provided
in this unit). The coil may be one-row or composite-type two-row.
Composite two-row coils are two single-row coils fabricated with
a single return bend end tubesheet.
Condenser Coil Maintenance and Cleaning
Recommendation
Routine cleaning of coil surfaces is essential to maintain proper
operation of the unit. Elimination of contamination and removal of
harmful residues will greatly increase the life of the coil and ex-
tend the life of the unit. The following maintenance and cleaning
procedures are recommended as part of the routine maintenance
activities to extend the life of the coil.
REMOVE SURFACE LOADED FIBERS
Surface loaded fibers or dirt should be removed with a vacuum
cleaner. If a vacuum cleaner is not available, a soft non-metallic
bristle brush may be used. In either case, the tool should be ap-
plied in the direction of the fins. Coil surfaces can be easily dam-
aged (fin edges can be easily bent over and cause damage to the
coating of a protected coil) if the tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose, against a
surface loaded coil will drive the fibers and dirt into the coil. This
will make cleaning efforts more difficult. Surface loaded fibers
must be completely removed prior to using low velocity clean wa-
ter rinse.
PERIODIC CLEAN WATER RINSE
A periodic clean water rinse is very beneficial for coils that are ap-
plied in coastal or industrial environments. However, it is very im-
portant that the water rinse is made with a very low velocity water
stream to avoid damaging the fin edges. Monthly cleaning as de-
scribed below is recommended.
ROUTINE CLEANING OF COIL SURFACES
Periodic cleaning with Totaline®environmentally sound coil
cleaner is essential to extend the life of coils. This cleaner is avail-
able from Replacement Components Division as part number
P902-0301 for a one gallon container, and part number P902-0305
for a 5 gallon container. It is recommended that all coils, including
standard aluminum, pre-coated, copper/copper or E-coated coils
be cleaned with the Totaline environmentally sound coil cleaner as
described below. Coil cleaning should be part of the unit’s regular-
ly scheduled maintenance procedures to ensure long life of the
coil. Failure to clean the coils may result in reduced durability in
the environment.
Avoid use of:
• coil brighteners
• acid cleaning prior to painting
• high pressure washers
• poor quality water for cleaning
Totaline environmentally sound coil cleaner is nonflammable, hy-
poallergenic, non-bacterial, and a USDA accepted biodegradable
agent that will not harm the coil or surrounding components such
as electrical wiring, painted metal surfaces, or insulation. Use of
non-recommended coil cleaners is strongly discouraged since coil
and unit durability could be affected.
ONE-ROW COIL
Wash coil with commercial coil cleaner. It is not necessary to re-
move top panel.
TWO-ROW COILS
Clean coil as follows:
1. Turn off unit power, tag disconnect.
2. Remove top panel screws on condenser end of unit.
3. Remove condenser coil corner post. See Fig. 16. To hold
top panel open, place coil corner post between top panel
and center post. See Fig. 17.
Fig. 16 — Cleaning Condenser Coil
Fig. 17 — Propping Up Top Panel
4. Remove screws securing coil to compressor plate and
compressor access panel.
5. Remove fastener holding coil sections together at return
end of condenser coil. Carefully separate the outer coil
section 3-in. to 4-in. from the inner coil section. See
Fig. 18.
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
This system uses Puron®refrigerant, which has higher pres-
sures than R-22 and other refrigerants. No other refrigerant
may be used in this system. Gage set, hoses, and recovery sys-
tem must be designed to handle Puron refrigerant. If unsure
about equipment, consult the equipment manufacturer.

13
Fig. 18 — Separating Coil Sections
6. Use a water hose or other suitable equipment to flush
down between the 2 coil sections to remove dirt and
debris. Clean the outer surfaces with a stiff brush in the
normal manner.
7. Secure inner and outer coil rows together with a field-sup-
plied fastener.
8. Reposition the outer coil section and remove the coil cor-
ner post from between the top panel and center post. Rein-
stall the coil corner post and replace all screws.
TOTALINE ENVIRONMENTALLY SOUND COIL
CLEANER APPLICATION EQUIPMENT
•2
1/2gallon garden sprayer
• Water rinse with low velocity spray nozzle
TOTALINE ENVIRONMENTALLY SOUND COIL
CLEANER APPLICATION INSTRUCTIONS
1. Proper eye protection such as safety glasses is recom-
mended during mixing and application.
2. Remove all surface loaded fibers and dirt with a vacuum
cleaner as described above.
3. Thoroughly wet all finned surfaces with clean water and a
low velocity garden hose, being careful not to bend fins.
4. Mix Totaline environmentally sound coil cleaner in a
21/2gallon garden sprayer according to the instructions
included with the cleaner. The optimum solution tempera-
ture is 100°F.
NOTE: Do NOT USE water in excess of 130°F, as the enzymatic
activity will be destroyed.
5. Thoroughly apply Totaline environmentally sound coil
cleaner solution to all coil surfaces including finned area,
tube sheets and coil headers.
6. Hold garden sprayer nozzle close to finned areas and apply
cleaner with a vertical, up-and-down motion. Avoid spraying
in horizontal pattern to minimize potential for fin damage.
7. Ensure cleaner thoroughly penetrates deep into finned
areas. Interior and exterior finned areas must be thor-
oughly cleaned. Finned surfaces should remain wet with
cleaning solution for 10 minutes. Ensure surfaces are not
allowed to dry before rinsing. Reapply cleaner as needed
to ensure 10 minute saturation is achieved.
8. Thoroughly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray noz-
zle. Protect fins from damage from the spray nozzle.
Evaporator Coil
CLEANING THE EVAPORATOR COIL
1. Turn unit power off. Install lockout tag. Remove evapora-
tor coil access panel.
2. If economizer or two-position damper is installed, remove
economizer by disconnecting Molex plug and removing
mounting screws.
3. Slide filters out of unit.
4. Clean coil using a commercial coil cleaner or dishwasher
detergent in a pressurized spray canister. Wash both sides
of coil and flush with clean water. For best results, back-
flush toward return-air section to remove foreign material.
Flush condensate pan after completion.
5. Reinstall economizer and filters.
6. Reconnect wiring.
7. Replace access panels.
THERMOSTATIC EXPANSION VALVE (TXV)
All 48HCs have a factory-installed nonadjustable thermostatic ex-
pansion valve (TXV). The TXV will be a bi-flow, bleed port ex-
pansion valve with an external equalizer. TXVs are specifically
designed to operate with Puron®or R-22 refrigerant. Use only fac-
tory authorized TXVs. Do not interchange Puron and R-22 TXVs.
TXV Operation
The TXV is a metering device that is used in air conditioning and
heat pump systems to adjust to the changing load conditions by
maintaining a preset superheat temperature at the outlet of the
evaporator coil.
The volume of refrigerant metered through the valve seat is de-
pendent upon the following:
1. Superheat temperature is sensed by cap tube sensing bulb on
suction tube at outlet of evaporator coil. This temperature is
converted into pressure by refrigerant in the bulb pushing
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit perfor-
mance or unit shutdown.
High velocity water from a pressure washer, garden hose, or
compressed air should never be used to clean a coil. The force
of the water or air jet will bend the fin edges and increase air-
side pressure drop.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in accelerated
corrosion of unit parts.
Harsh chemicals, household bleach or acid or basic cleaners
should not be used to clean outdoor or indoor coils of any kind.
These cleaners can be very difficult to rinse out of the coil and
can accelerate corrosion at the fin/tube interface where
dissimilar materials are in contact. If there is dirt below the
surface of the coil, use the Totaline environmentally balanced
coil cleaner.

14
downward on the diaphragm, which opens the valve using the
push rods.
2. The suction pressure at the outlet of the evaporator coil is
transferred through the external equalizer tube to the
underside of the diaphragm.
3. The pin is spring loaded, which exerts pressure on the
underside of the diaphragm. Therefore, the bulb pressure
works against the spring pressure and evaporator suction
pressure to open the valve. If the load increases, the tem-
perature increases at the bulb, which increases the pressure
on the top side of the diaphragm. This opens the valve and
increases the flow of refrigerant. The increased refrigerant
flow causes the leaving evaporator temperature to
decrease. This lowers the pressure on the diaphragm and
closes the pin. The refrigerant flow is effectively stabilized
to the load demand with negligible change in superheat.
Replacing TXV
1. Recover refrigerant.
2. Remove TXV support clamp using a 5/l6-in. nut driver.
3. Remove TXV using a wrench and an additional wrench on
connections to prevent damage to tubing.
4. Remove equalizer tube from suction line of coil. Use file
or tubing cutter to cut brazed equalizer line approximately
2 inches above suction tube.
5. Remove bulb from vapor tube inside cabinet.
6. Install the new TXV using a wrench and an additional
wrench on connections to prevent damage to tubing while
attaching TXV to distributor.
7. Attach the equalizer tube to the suction line. If the coil has
a mechanical connection, then use a wrench and an addi-
tional wrench on connections to prevent damage. If the
coil has a brazed connection, use a file or a tubing cutter to
remove the mechanical flare nut from the equalizer line.
Then use a new coupling to braze the equalizer line to the
stub (previous equalizer line) in suction line.
8. Attach TXV bulb in the same location where the original
(in the sensing bulb indent) was when it was removed,
using the supplied bulb clamps. See Fig. 19.
9. Route equalizer tube through suction connection opening
(large hole) in fitting panel and install fitting panel in
place.
10. Sweat the inlet of TXV marked “IN” to the liquid line.
Avoid excessive heat which could damage the TXV valve.
Use quenching cloth when applying heat anywhere on TXV.
Refrigerant System Pressure Access Ports
There are two access ports in the system: on the suction tube
near the compressor and on the discharge tube near the compres-
sor. These are brass fittings with black plastic caps. The hose
connection fittings are standard 1/4-in. SAE male flare couplings.
The brass fittings are two-piece high flow valves, with a receptacle
base brazed to the tubing and an integral spring-closed check
valve core screwed into the base. See Fig. 20. This check valve is
permanently assembled into this core body and cannot be serviced
separately; replace the entire core body if necessary. Service tools
are available from RCD that allow the replacement of the check
valve core without having to recover the entire system refrigerant
charge. Apply compressor refrigerant oil to the check valve core’s
bottom o-ring. Install the fitting body with 96 ± 10 in.-lb (10.85 ±
1.1 Nm) of torque; do not over-tighten.
Fig. 19 — TXV Valve and Sensing Bulb Location
Fig. 20 — CoreMax1Access Port Assembly
TXV SENSING
BULB
CLAMP
THERMAL EXPANSION
(TXV) VALVE
SENSING BULB INSULATION REMOVED FOR CLARITY
1. CoreMax is a registered trademark of Fastest, Inc.
5/8” HEX 0.47
30°
0.596
1/2-20 UNF RH
1/2” HEX
45°
WASHER
O-RING
7/16-20 UNF RH
DEPRESSOR PER AHRI 720
+.01/-.035
FROM FACE OF BODY
Thissurface providesametal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
SEAT CORE
(Part No. EC39EZ067)

15
PURON®(R-410A) REFRIGERANT
This unit is designed for use with Puron (R-410A) refrigerant. Do
not use any other refrigerant in this system.
Puron (R-410A) refrigerant is provided in pink (rose) colored cyl-
inders. These cylinders are available with and without dip tubes;
cylinders with dip tubes will have a label indicating this feature.
For a cylinder with a dip tube, place the cylinder in the upright po-
sition (access valve at the top) when removing liquid refrigerant
for charging. For a cylinder without a dip tube, invert the cylinder
(access valve on the bottom) when removing liquid refrigerant.
Because Puron (R-410A) refrigerant is a blend, it is strongly rec-
ommended that refrigerant always be removed from the cylinder
as a liquid. Admit liquid refrigerant into the system in the dis-
charge line. If adding refrigerant into the suction line, use a com-
mercial metering/expansion device at the gage manifold; remove
liquid from the cylinder, pass it through the metering device at the
gage set and then pass it into the suction line as a vapor. Do not re-
move Puron (R-410A) refrigerant from the cylinder as a vapor.
Refrigerant Charge
Amount of refrigerant charge is listed on the unit’s nameplate. Re-
fer to Carrier GTAC2-5 Charging, Recovery, Recycling and Rec-
lamation training manual and the following procedures.
Unit panels must be in place when unit is operating during the
charging procedure.
NO CHARGE
Use standard evacuating techniques. After evacuating system,
weigh in the specified amount of refrigerant.
LOW-CHARGE COOLING
Using Fig. 21-29, vary refrigerant until the conditions of the ap-
propriate chart are met. Note the charging charts are different from
type normally used. Charts are based on charging the units to the
correct sub-cooling for the various operating conditions. Accurate
pressure gage and temperature sensing device are required. Con-
nect the pressure gage to the service port on the liquid line. Mount
the temperature sensing device on the liquid line and insulate it so
that outdoor ambient temperature does not affect the reading. In-
door-air cfm must be within the normal operating range of the
unit.
EXAMPLE:
Model 48HC*A04
Outdoor Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 85°F (29°C)
Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . 140 psig (965 kPa)
Suction Temperature should be . . . . . . . . . . . . . . . . . . 60°F (16°C)
USING COOLING CHARGING CHARTS
Take the outdoor ambient temperature and read the liquid pressure
gage. Refer to chart to determine what liquid temperature should
be. If liquid temperature is low, add refrigerant. If liquid tempera-
ture is high, carefully recover some of the charge. Recheck the liq-
uid pressure as charge is adjusted.
COOLING CHARGING CHARTS
Fig. 21 — Cooling Charging Chart - 3 Ton
Fig. 22 — Cooling Charging Chart - 4 Ton
48HC SIZE DESIGNATION NOMINAL TONS REFERENCE
04 3
05 4
06 5
07 6
08 7.5
09 8.5
12 10
14 12.5
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – OUTDOOR FAN MUST BE RUNNING
160
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure (psig)
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
Add charge if above the curve
Remove charge if below the curve
48TM502520 REV C
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – OUTDOOR FAN MUST BE RUNNING
Remove charge if below the curve
Add charge if above the curve
160
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure (psig)
48TM502521 REV C

16
Fig. 23 — Cooling Charging Chart - 5 Ton
Fig. 24 — Cooling Charging Chart - 6 Ton
Fig. 25 — Cooling Charging Chart - 2 Stage 6 Ton
Fig. 26 — Cooling Charging Chart - 7.5 Ton
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – OUTDOOR FAN MUST BE RUNNING
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
160
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure (psig)
48TM502522 REV C
Remove charge if below the curve
Add charge if above the curve
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – ALL OUTDOOR FANS MUST BE RUNNING
Compressor Discharge Pressure (psig)
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
48TM502680 REV B
150 200 250 300 350 400 450 500 550 600
20
40
60
80
100
120
140
160
Add charge if above the curve
Remove charge if below the curve
350 700 1050 1400 1750 2100 2450 2800 3150 3500 3850
-6
0
6
12
18
24
30
36
42
48
54
60
20
40
60
80
100
120
140
50 100 150 200 250 300 350 400 450 500 550 600
Temperature at Liquid Valve (°C / °F)
Compressor Discharge Pressure (PSIG / Kpa)
2-Stage 6 Ton Charging Chart R-410A Refrigerant
(Cooling Mode - Compressor at Full Load
and Outdoor Fans at High Speed)
REV-
48TM002738
Remove Charge if
Below the Curve
Add Charge if
Above the Curve
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – ALL OUTDOOR FANS MUST BE RUNNING
Compressor Discharge Pressure (psig)
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
48TM502681 REV B
Remove charge if below the curve
Add charge if above the curve
160
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600

17
Fig. 27 — Cooling Charging Chart - 8.5 Ton
Fig. 28 — Cooling Charging Chart - 10 Ton
Fig. 29 — Cooling Charging Chart - 12.5 Ton - Circuit A and B
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – ALL OUTDOOR FANS MUST BE RUNNING
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
Compressor Discharge Pressure (psig)
48TM502682 REV B
Remove charge if below the curve
Add charge if above the curve
160
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
CHARGING CHART – R-410A REFRIGERANT
COOLING MODE – CIRCUIT A & B
Compressor Discharge Pressure (psig)
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
48TM504393 REV D
Remove charge if below the curve
Add charge if above the curve
600
550500
450400
350300
250200
150
20
40
60
80
100
120
140
160
12.5 TON CIRCUIT A CHARGING CHART
(COOLING MODE ONLY)
(R410A REFRIGERANT)
12.5 TON CIRCUIT B CHARGING CHART
(COOLING MODE ONLY)
(R410A REFRIGERANT)
Remove charge if below the curve
Add charge if above the curve
Remove charge if below the curve
Add charge if above the curve
50TM501188 B
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
Outdoor Coil Leaving Refrigerant Temperature (Degrees F)
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
140
120
100
80
60
40
20
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure (psig) Compressor Discharge Pressure (psig)

18
COMPRESSOR
Lubrication
The compressor is charged with the correct amount of oil at the
factory.
Replacing Compressor
NOTE: Only factory-trained service technicians should remove
and replace compressor units.
Compressor Rotation
NOTE: When the compressor is rotating in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine if
the compressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
NOTE: If the suction pressure does not drop and the discharge
pressure does not rise to normal levels, the evaporator fan is prob-
ably also rotating in the wrong direction.
4. Turn off power to the unit.
5. Reverse any two of the three unit power leads.
6. Reapply electrical power to the compressor. The suction
pressure should drop and the discharge pressure should
rise, which is normal for scroll compressors on start-up.
7. Replace compressor if suction/discharge pressures are not
within specifications for the specific compressor.
The suction and discharge pressure levels should now move to
their normal start-up levels.
Filter Drier
Replace whenever refrigerant system is exposed to atmosphere.
Only use factory-specified liquid-line filter driers with working
pressures no lower than 650 psig. Do not install a suction-line fil-
ter drier in liquid line. A liquid-line filter drier designed for use
with Puron refrigerant is required on every unit.
Condenser-Fan Adjustment
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig. 30.
5. Tighten setscrews.
6. Replace condenser-fan assembly.
Fig. 30 — Condenser Fan Adjustment
See Fig. 31 for a typical piping schematic.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to compo-
nents.
The compressor is in a Puron®refrigerant system and uses a
polyolester (POE) oil. This oil is extremely hygroscopic,
meaning it absorbs water readily. POE oils can absorb
15 times as much water as other oils designed for HCFC and
CFC refrigerants. Avoid exposure of the oil to the atmosphere.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use air or gases containing oxygen for leak testing or for
operating refrigerant compressors. Pressurized mixtures of air
or gases containing oxygen can lead to an explosion.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use non-certified refrigerants in this product. Non-certi-
fied refrigerants could contain contaminates that could lead to
unsafe operating conditions. Use ONLY refrigerants that con-
form to AHRI Standard 700.
CAUTION
INSTALLATION SITE DAMAGE
Failure to follow this caution can result in damage to equip-
ment location site.
Puron (R-410A) refrigerant contains polyolester (POE) oil that
can damage the roof membrane. Caution should be taken to
prevent POE oil from spilling onto the roof surface.
The factory also recommends that the suction and discharge
lines be cut with a tubing cutter instead of using a torch to re-
move brazed fittings.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in premature wear and
damage to equipment.
Scroll compressors can only compress refrigerant if rotat-
ing in the right direction. Reverse rotation for extended
times can result in internal damage to the compressor.
Scroll compressors are sealed units and cannot be repaired
on site location.
CONDUIT
0.14 in. + 0.0 / -0.03

19
Fig. 31 — Typical Piping Schematic (Dual Circuit Unit Shown)
FILTER
DRIER
FILTER
DRIER
OUTDOOR COIL
INDOOR COIL
TXV 2
TXV1
COOLING LIQUID LINES
LPS/LOC
HPS1
COMPRESSOR
COMP 1
HPS2
COMPRESSOR
COMP 2

20
CONVENIENCE OUTLETS
CONVENIENCE OUTLETS
Two types of convenience outlets are offered on 48HC models:
non-powered and unit-powered. Both types provide a 125 vac
Ground-Fault Circuit-Interrupt (GFCI) duplex receptacle rated at
15A behind a hinged waterproof access cover, located on the end
panel of the unit. See Fig. 32.
Fig. 32 — Convenience Outlet Location
INSTALLING WEATHERPROOF COVER
A weatherproof while-in-use cover for the factory installed conve-
nience outlets is now required by UL standards. This cover cannot
be factory-mounted due to its depth. The cover must be installed at
unit installation. For shipment, the convenience outlet is covered
with a blank cover plate.
The weatherproof cover kit is shipped in the unit’s control box.
The kit includes the hinged cover, a backing plate and gasket.
NOTE: DISCONNECT ALL POWER TO UNIT AND CONVE-
NIENCE OUTLET. Use approved lockout/tag-out procedures.
1. Remove the blank cover plate at the convenience outlet;
discard the blank cover.
2. Loosen the two screws at the GFCI duplex outlet, until
approximately 1/2-in. (13 mm) under screw heads are
exposed.
3. Press the gasket over the screw heads. Slip the backing
plate over the screw heads at the keyhole slots and align
with the gasket; tighten the two screws until snug (do not
over-tighten).
4. Mount the weatherproof cover to the backing plate as
shown in Fig. 33.
5. Remove two slot fillers in the bottom of the cover to per-
mit service tool cords to exit the cover.
6. Check cover installation for full closing and latching.
Fig. 33 — Weatherproof Cover Installation
NON-POWERED TYPE
This type requires the field installation of a general-purpose 125-v
15-A circuit powered from a source elsewhere in the building. Ob-
serve national and local codes when selecting wire size, fuse or
breaker requirements and disconnect switch size and location.
Route 125-v power supply conductors into the bottom of the utili-
ty box containing the duplex receptacle.
UNIT-POWERED TYPE
A unit-mounted transformer is factory-installed to step-down the
main power supply voltage to the unit to 115-v at the duplex re-
ceptacle. This option also includes a manual switch with fuse, lo-
cated in a utility box and mounted on a bracket behind the conve-
nience outlet; access is through the unit’s control box access panel.
See Fig. 32.
The primary leads to the convenience outlet transformer are not
factory-connected. Selection of primary power source is a custom-
er option. If local codes permit, the transformer primary leads can
be connected at the line-side terminals on a unit-mounted non-
fused disconnect or Heating, Air Conditioning and Refrigeration
(HACR) breaker switch; this will provide service power to the
unit when the unit disconnect switch or HACR switch is open.
Other connection methods will result in the convenience outlet cir-
cuit being de-energized when the unit disconnect or HACR switch
is open. See Fig. 34.
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Units with convenience outlet circuits may use multiple dis-
connects. Check convenience outlet for power status before
opening unit for service. Locate its disconnect switch, if appro-
priate, and open it. Lock-out and tag-out this switch, if neces-
sary.
CONVENIENCE
OUTLET GFCI
PWD-CO FUSE
SWITCH
PWD-CO TRANSFORMER
CONTROL BOX
ACCESS PANEL
COVER - WHILE-IN-USE
WEATHERPROOF
BASEPLATE FOR
GFCI RECEPTACLE
GASKET
GFCI RECEPTACLE
NOT INCLUDED
TOP
TOP
TOP
WET LOCA
TIONS
WETLOCATIONS