Carrier 50FC 04 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. 04-53500336-01 Printed in U.S.A. Form 50FC-4-7-02SM Pg 1 7-23 Replaces: 50FC-4-7-01SM
Service and Maintenance Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 2
UNIT ARRANGEMENT AND ACCESS . . . . . . . . . . . . 3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 3
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SUPPLY FAN (BLOWER) SECTION . . . . . . . . . . . . . . 4
Supply Fan (Direct-Drive) . . . . . . . . . . . . . . . . . . . . . . 4
Staged Air Volume . . . . . . . . . . . . . . . . . . . . . . . . . . 10
COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Condenser Coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Condenser Coil Maintenance and Cleaning 
Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . 10
Evaporator Coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Evaporator Coil Metering Devices . . . . . . . . . . . . . . 12
THERMOSTATIC EXPANSION VALVE (TXV) . . . . . 13
TXV Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Replacing TXV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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 . . . . . . . . . . . . . . . . . . . . 19
Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Condenser-Fan Adjustment . . . . . . . . . . . . . . . . . . . 19
Troubleshooting Cooling System . . . . . . . . . . . . . . 20
CONVENIENCE OUTLETS . . . . . . . . . . . . . . . . . . . . 21
Convenience Outlets . . . . . . . . . . . . . . . . . . . . . . . . 21
Installing Weatherproof Cover . . . . . . . . . . . . . . . . . 21
Non-Powered Type . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Unit-Powered Type . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Fuse on Powered Type . . . . . . . . . . . . . . . . . . . . . . . 22
ELECTRIC HEATERS . . . . . . . . . . . . . . . . . . . . . . . . 22
Completing Heater Installation . . . . . . . . . . . . . . . . 23
SMOKE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . 24
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Smoke Detector Sensor . . . . . . . . . . . . . . . . . . . . . . 24
Smoke Detector Locations . . . . . . . . . . . . . . . . . . . . 24
Completing Installation of Return Air Smoke
Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
FIOP Smoke Detector Wiring and Response . . . . . 26
SENSOR AND CONTROLLER TESTS . . . . . . . . . . .27
Sensor Alarm Test . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Controller Alarm Test . . . . . . . . . . . . . . . . . . . . . . . .27
Dirty Controller Test . . . . . . . . . . . . . . . . . . . . . . . . .27
Dirty Sensor Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Changing the Dirt Sensor Test . . . . . . . . . . . . . . . . .27
Remote Station Test . . . . . . . . . . . . . . . . . . . . . . . . .27
SD-TRK4 Remote Alarm Test Procedure . . . . . . . .27
Remote Test/Reset Station Dirty Sensor Test . . . .28
Dirty Sensor Test Using an SD-TRK4 . . . . . . . . . . .28
Detector Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
PROTECTIVE DEVICES . . . . . . . . . . . . . . . . . . . . . . .29
Compressor Protection . . . . . . . . . . . . . . . . . . . . . . .29
Relief Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Control Circuit, 24-V . . . . . . . . . . . . . . . . . . . . . . . . .30
SYSTEMVU CONTROL SYSTEM . . . . . . . . . . . . . . . .30
SystemVu Interface . . . . . . . . . . . . . . . . . . . . . . . . . .30
Additional SystemVu Installation and
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .30
RTU OPEN CONTROL SYSTEM . . . . . . . . . . . . . . . .31
Sensory/Accessory Installation . . . . . . . . . . . . . . . .31
Additional RTU Open Installation and
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .32
ECONOMIZER SYSTEMS . . . . . . . . . . . . . . . . . . . . .32
EconoMi$er 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
EconoMi$er IV (Field-Installed Accessory) . . . . . . .34
Economi$er X (Factory Option) . . . . . . . . . . . . . . . .41
PRE-START-UP/START-UP . . . . . . . . . . . . . . . . . . . .54
START-UP, GENERAL . . . . . . . . . . . . . . . . . . . . . . . .54
Unit Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Additional Installation/Inspection . . . . . . . . . . . . . .54
Return-Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Outdoor-Air Inlet Screens . . . . . . . . . . . . . . . . . . . . .54
Compressor Mounting . . . . . . . . . . . . . . . . . . . . . . .54
Internal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Refrigerant Service Ports . . . . . . . . . . . . . . . . . . . . .54
Compressor Rotation . . . . . . . . . . . . . . . . . . . . . . . .55
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Ventilation (Continuous Fan) . . . . . . . . . . . . . . . . . .55
FASTENER TORQUE VALUES . . . . . . . . . . . . . . . . .55
START-UP, RTU OPEN CONTROLS . . . . . . . . . . . . .55
START-UP, SYSTEMVU CONTROLS . . . . . . . . . . . .55
APPENDIX A — MODEL NUMBER 
NOMENCLATURE . . . . . . . . . . . . . . . . . . . . . . . . . .56
APPENDIX B — PHYSICAL DATA . . . . . . . . . . . . . . .57
APPENDIX C — FAN PERFORMANCE . . . . . . . . . . .64
50FC-*04-07
Single Package Rooftop Electric Cooling Unit
with Puron®(R-410A) Refrigerant
3 to 6 Nominal Tons

2
APPENDIX D — WIRING DIAGRAMS . . . . . . . . . . . . 93
APPENDIX E — LOW AMBIENT CONTROL 
SENSOR LOCATION . . . . . . . . . . . . . . . . . . . . . . 115
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
literature, tags and labels attached to the unit, and other safety
precautions that may apply.
Follow all safety codes. 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 instructions 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.
Before performing service or maintenance operations on unit,
LOCKOUT/TAGOUT the main power switch to unit.
Electrical shock and rotating equipment could cause severe
injury.
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Units with convenience outlet circuits can use multiple
disconnects. Check convenience outlet for power status before
opening unit for service. Locate the disconnect switch and lock
it in the open position it. LOCKOUT/TAGOUT this switch to
notify others.
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
R-410A refrigerant systems operate at higher pressures than
standard R-22 systems. Do not use R-22 service equipment or
components on R-410A refrigerant equipment.
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-
certified refrigerants could contain contaminates that could
lead to unsafe operating conditions. Use ONLY refrigerants
that conform to AHRI Standard 700.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit
performance 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
airside pressure drop.
IMPORTANT: Lockout/Tag-out is a term used when electrical
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.

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
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
• 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
• Ensure outdoor fan motor mounting bolts are tight
• Ensure compressor mounting bolts are tight
• Inspect outdoor fan blade positioning
• Ensure control box is clean
• Check control box wiring condition
• Ensure wire terminals are tight
• Check refrigerant charge level
• Ensure indoor coils are clean
• Check supply blower motor amperage
Electric Heating
• Inspect power wire connections
• Ensure fuses are operational
• Ensure manual reset limit switch is closed
Economizer or Outside Air Damper
• Check 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
replaced or cleaned.
Filters
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. 3.)
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.
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.)
Filter Access Panel
Outdoor-Air Opening and
Indoor Coil Access Panel
Compressor
Access Panel
Control Box
Access Panel
Indoor
Access
Panel
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
possibly resulting in a small fire. Dirt buildup on components
can cause excessive current used resulting in motor failure.

4
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
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
All low-voltage wiring should be routed through the provided
raceway built into the corner post of the unit or secured to the unit
control box with the electrical conduit in order to provide UL-
required clearance between high and low-voltage wiring.
Supply Fan (Direct-Drive)
All FC units have the EcoBlue™direct drive vane axial fan sys-
tem. The fan is driven by an ECM motor with speed that is user set
through the Unit Control Board (UCB). Speeds are fully configu-
rable from 40% to 100% of motor’s maximum speed. See Fig. 5
and 6.
Fig. 5 — Direct-Drive Supply Fan Assembly
Fig. 6 — ECM Motor Plug Connectors
EVALUATING MOTOR SPEED
The direct drive ECM blower motor uses a constant speed design.
Motor speed is controlled by a 0-10 vdc signal, where 10 vdc is
equal to motor’s maximum rpm.
SELECTING FAN SPEED
All units come factory set for 7.8 vdc or approximately 78% of the
motor’s maximum speed. Fan speed should be set per job specifi-
cation cfm (cubic feet per minute) and ESP (external static pres-
sure) required and per Fan speed set up label included on the unit’s
high voltage cover. In some cases, the Fan Speed Set Up label may
already include the field setting if unit was previously installed.
Check the box on the lower half of the label to see if the field volt-
age setting was filled in and if so, set fan speed to that voltage.
Otherwise see detailed instructions below.
NOTE: Fan Speed Set-Up is for full load airflow. If the unit has
multiple stages of cooling, low cool and ventilation may operate at
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.
Electrical shock and rotating equipment could cause severe
injury.
17 1/4"
Divider
Barometric
Relief
Cleanable
Aluminum
Filter Filter
Hood
Filter
Clip
Outside
Air
Screws
Motor
Plug
Fan
Rotor
ECM
Motor
321
654
987
BLUE
YELLOW
BLACK
GRN/YEL
ORANGE
GRAY
Power L3 (3 phase only)
Power L2
Power L1
Earth Ground
WHITE CTL Signal Common
10vdc Source
0–10vdc Signal

5
lower fan rpms. This offset is factory set and controlled by the
UCB. If fan speed verification is being done with a strobe, fan
speed should be verified in all unit operation modes.
Units with Electro-mechanical controls
The Fan Speed set up controls are located on the lower section
of the Unit Control Board (UCB). See Fig. 7 for location.
1. Check the job specifications for the cfm (cubic feet per
minute) and ESP (external static pressure) required.
2. Using the chart on the Fan Speed Set Up labels (see
Fig. 8), calculate the vdc from the cfm and ESP for the
base unit.
3. If installing any accessories listed at the bottom of the Set
Up Label, add accessory vdc to base unit vdc in upper por-
tion of label. For electric heaters use only one adder (e.g.,
2 stage heater uses only 2 stage adder, not 1 stage plus
2 stage).
NOTE: The Fan Speed Set Up labels are located on the High Volt-
age cover in the Control Box.
4. Connect a multimeter to the vdc terminals on the UCB.
5. Set the Range Switch to either A, B, or C per the Switch
Range table.
6. Using a straight blade screwdriver turn the vdc control dial
to fine tune the vdc reading.
7. Record the reading in the Field Setting field.
Low Speed Fan Adjustment
2-Pin DIP Switch
The Low Speed 2-Pin DIP switch is located near the center of the
UCB. See Fig. 7.
When replacing UCB, the board will be shipped as default without
a low speed selected. To select correct FC low fan speed for 3 to
5 ton 50FC units set both DIP switches to “OFF” (0). For 6 ton
50FC units set both DIP switches “ON” (1). See Table 1. The DIP
switch positions can also be found on the unit's control label
diagram. Fig. 7 — UCB Fan Speed Controls
Table 1 — Low Speed 2-Pin DIP Switch Settings
UNIT SIZE
(tons)
LOW SPEED % OF USER SET
FAN SPEED
DIP1 DIP2
3, 4, 5 0 0 100%
611 66%
Fan Speed Set Up Controls

6
NOTE: Values in the Field Accessories section are vdc adders.
Fig. 8 — Example of Fan Speed Set Up Labels for Electro-Mechanical Controls
Factory Setting:
9.0 VDC
Field Setting:
V
Switch Range:
A
B
C
B
AC
Field Accessories:
ESP in. wg
VDC Calculator
CFM
0.2
5.4
5.8
6.1
6.5
6.8
7.2
7.6
7.9
8.3
1500
1625
1750
1875
2000
2125
2250
2375
2500
0.1
0.4
6.2
6.5
6.8
7.1
7.4
7.7
8.0
8.4
8.7
0.1
0.6
6.9
7.1
7.4
7.7
7.9
8.2
8.5
8.8
0.1
0.8
7.5
7.7
8.0
8.2
8.5
8.7
9.0
0.1
1.0
8.1
8.3
8.5
8.7
9.0
0.1
1.2
8.6
8.8
9.0
9.2
0.1
1.4
9.1
9.3
9.5
0.1
1.6 1.8 2.0
9.6
0.1Economizer
1 Stage E Heat
2 Stage E Heat
UNIT MODEL NUMBER
4.1 - 7.5
6.9 - 8.7
7.7 - 10.0
0.2
0.3
0.2
0.3
0.2
0.3
0.2
0.3
0.2
0.3
0.2
0.3
0.2
0.3
0.2
0.3
9.8
9.9
9.7
9.99.5
9.7
10.0
9.2
9.5
9.8
9.3
9.69.2
Record field setting here
*
*Overlap in A, B, C switch range
designed for maximum field
adjustment potential. For example
7.2 can be set at either A or B.

7
Units with SystemVu™controls
On units equipped with the factory-installed SystemVu controller
the Fan Speed settings are accessed through the SystemVu
interface.
1. Check the job specifications for the cfm (cubic feet per
minute) and ESP (external static pressure) required.
2. Using the chart on the Fan Speed Set Up labels (see Fig. 9),
calculate the rpm from the cfm and ESP for the base unit.
3. If installing any accessories listed at the bottom of the Set Up
Label, add accessory rpm to base unit rpm in upper portion of
label. For electric heaters use only one adder (e.g., 2 stage
heater uses only 2 stage adder, not 1 stage plus 2 stage).
NOTE: The Fan Speed Set Up labels are located on the High Volt-
age cover in the Control Box.
4. Press any key on the SystemVu interface to activate the
display backlight and then press the MENU key.
5. Using the UP and DOWN arrow keys highlight SET-
TINGS and then press ENTER.
6. Use the DOWN arrow key highlight the UNIT CONFIG-
URATIONS menu then press ENTER.
7. Highlight UNIT CONFIGURATIONS then press ENTER.
8. Highlight INDOOR FAN and then press ENTER.
9. Refer to the job specifications to set the following, deter-
mining the values per the rpm Calculator label (see Fig. 9).
Use the UP and DOWN arrow keys and the BACK key to
set the values. Press ENTER after setting each value to
continue to the next selection.
• IDF VENT SPD
• IDF HEAT SPD
•IDFLOWCOOLSPD
• IDF HIGH SPD
• IDF FREE COOL SPD
For further details see the FC/GC Series Single Package Rooftop
Units with SystemVu Controller Controls, Start-up, Operation and
Troubleshooting manual.
NOTE: Values in the Field Accessories section are vdc adders.
Fig. 9 — Example of Fan Speed Set Up Labels for SystemVu™Controls
A
Field Accessories:
2500
Economizer
ESP in. wg
RPM Calculator
CFM
0.2
1301
1381
1463
1548
1633
1720
1808
1897
1987
1500
1625
1750
1875
2000
2125
2250
2375
66
80
107
0.4
1477
1544
1615
1688
1764
1842
1921
2003
2068
66
0.6
1639
1699
1763
1828
1897
1967
2040
2115
2191
0.8
1788
1843
1902
1962
2025
2090
2157
2227
2298
66
1.0
1925
1976
2031
2087
2146
2208
2271
2336
66
1.2
2054
2101
2152
2206
2262
2320
2380
66
1.4
2174
2220
2268
2318
2372
66
1.6 1.8 2.0
2289
2332
2378
66 66
80 80 80 80 80 80 80
107 107 107 107 107 107 107
1 Stage E Heat
2 Stage E Heat
UNIT MODEL NUMBER

8
TROUBLESHOOTING THE ECM MOTOR
EcoBlue™motors are designed with several built-in protections
included in the motor software. If the motor detects a fault it will
safely shut down. For temperature related faults the motor requires
a line voltage reset to continue operation. For all others, the motor
will resume operation automatically as soon as the fault condition
is cleared. See Table 2 for a complete list.
Troubleshooting the motor requires a voltmeter.
1. Disconnect main power to the unit.
2. Disconnect motor plug in supply section of the unit.
3. Restore main unit power.
4. Check for proper line voltage at motor power leads Black
(PL1-1), Yellow (PL1-2), and Blue (PL1-3). Blue is only
present on 3-phase motors. See the following table.
5. Disconnect main power.
6. Reconnect motor plug in supply section of unit.
7. Restore main power.
8. Check for proper motor control voltage signal of 9.7 vdc
to 10.3 vdc at IFM-1 and IFM-3 on Unit Control Board
(UCB). See Fig. 10.
9. Using a jumper wire from unit control terminals R to G,
engage motor operation.
10. Verify control signal from user speed selection switch by
placing voltmeter taps in provided terminals marked vdc.
Signal should be between 3.8 vdc and 10.3 vdc.
11. If the motor does not start and run, remove the fan assem-
bly and replace the motor with one having the same part
number. Do not substitute with an alternate design motor
as the voltage/speed programming will not be the same as
that on an original factory motor.
Fig. 10 — Supply Fan Control Wiring Diagram
Removing the Motor and Fan Assembly
NOTE: Due to press fit design of composite Rotor on Motor, it is
highly recommended that any time a motor is replaced the fan ro-
tor is replaced as well. The rest of the assembly may be reused.
See Fig. 11.
1. Unplug motor harness from control box harness and cut
wire tie at the fan deck.
2. Unplug connectors from stator temperature limit switch.
3. Remove two screws at front of stator on fan deck.
4. Slide fan assembly forward a couple of inches to clear rear
brackets and lift assembly out.
Fig. 11 — Fan Assembly Removal
Table 2 — Fault Condition/Reset Trigger
FAULT
CONDITION
RESET
TRIGGER DESCRIPTION
Phase Failure Automatic
One phase is missing or imbalanced. In
this case the motor will come to a stop
and then automatically restart when all
phases are present.
Locked/
Blocked Rotor Automatic
The rotor is blocked. Once the locking
mechanism has been removed, the
motor will automatically restart.
Motor Over
Heated Manual
The motor will stop in the event the
motor over heats. In this case there has
to be a manual restart.
Power Module
Over Heated Manual
The motor will stop in the event the
electronics over heat. In this case there
has to be a manual restart.
Line under-
voltage Automatic
Once the line voltage returns within
permitted operating range, the fan will
automatically restart.
Communication
Error Automatic
Internal communication error of the
fan’s electronics. The fan will restart
automatically, if error is cleared.
50FC UNIT
VOLTAGE MOTOR VOLTAGE MINIMUM-MAXIMUM VOLTS
208/230 230 187-253
460 460 360-506
575 575 517-633
4
2
1
3

9
Disassembling Motor and Fan Assembly
See Fig. 12.
1. Remove six screws from retaining rings in the top of the
fan rotor.
2. Remove rotor from motor.
3. Remove four screws connecting motor to stator flange.
4. Remove stator from motor.
5. If required, remove stator limit switch on aluminum stator.
6. Remove three screws from the heat shield. Retain the heat
shield if a new heat shield has not been ordered.
Fig. 12 — Disassembling Motor and Fan Assembly
Reassembly of Motor and Fan Assembly
See Fig. 13.
1. Install heat shield on motor with three no. 8-32 x 3/8 in.
thread cutting screws (P/N: AK92AB100). Tighten to
30 in.-lb (3.39 Nm).
2. Place motor on flat surface.
Fig. 13 — Fan System Re-Assembly
3. If required, install stator limit switch on aluminum stator
with two no. 10 x 5/8 in. hex head screws
(P/N: AL48AM217). Tighten to 50 in.-lb (5.65 Nm).
4. If required, insert composite ring into aluminum stator
where pegs match up with holes.
5. Line up rectangle key way in the center of stator with rect-
angle feature on motor and set stator onto motor.
6. Install four no. 10-32 x 1/2 in. hex head machine screws
(P/N: AD07AB126) to connect aluminum stator to motor.
Tighten to 23 in.-lb (2.6 Nm).
7. Fit grommet on motor wire harness into keyhole feature on
the side of the stator and pull wire harness out through
grommet.
8. Install rotor on motor by lining up one of 9 holes on com-
posite rotor with one of 9 holes on motor flange. This can
be done by adjusting motor and the top of the motor hub
and aligning using a 3/16 in. Allen key or similar pin.
Press fan rotor down until it is flush with the motor flange.
1
2
3
4
6
5
2
10
8
6
3
9
4
1
77
5

10
9. Set retaining rings (x3) into composite rotor and install
6 no. 10-32 x 1/2 in. hex head machine screws
(P/N: AD07AB126) through the holes in retaining rings.
Tighten to 23 in.-lb (2.6 Nm). It is recommended this
screw installation be done in a star pattern.
10. Align tabs of composite casing with rectangular cutouts on
top of aluminum stator and snap into place.
11. Final assembly should have a small clearance between top of
plastic rotor and underside of casing lip. Spin rotor by hand
to ensure no contact or rubbing between these two parts.
Reinstalling Motor and Fan Assembly
See Fig. 14.
1. Align motor harness/grommet at ~7 o’clock (facing
installer) and align the bottom flats on right and left sides
of fan stator with fan deck ribs. Drop fan assembly down
into fan deck opening and slide back until aluminum stator
is under the rear fan deck brackets.
2. Align (if necessary) two front holes and fasten stator to fan
deck with 2 no. 10 x 5/8 in. hex head screws
(P/N: AL48AM217). Tighten to 50 in.-lb (5.65 Nm).
3. Reconnect wires for stator temperature limit switch.
4. Pull motor harness tight through grommet and plug it in to
the control box harness and secure in the corner with snap-
in wire tie.
Fig. 14 — Fan Assembly Install
Staged Air Volume
All 50FC**04-07 units with EcoBlue™technology come factory
set to automatically adjust the indoor fan motor speed in sequence
with the unit’s ventilation, cooling, and heating operation. When
the first stage of cooling is requested, unit fan will operate at 66%
of the user set full load airflow. When the second stage of cooling
is required, UCB will allow the full design airflow rate for the unit
(100%). During the heating mode, the unit will allow total design
airflow rate (100%). During ventilation mode, the fan will operate
at 66% speed.
See Table 1 on page 5 for 2-Pin DIP switch settings.
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 Nomenclature 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 fabri-
cated 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 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. Rinsing coils in the opposite di-
rection of airflow is recommended.
1
3
4
2
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
This system uses R-410A refrigerant, which has higher
pressures than R-22 and other refrigerants. No other
refrigerant may be used in this system. Gauge set, hoses, and
recovery system must be designed to handle R-410A
refrigerant. If unsure about equipment, consult the equipment
manufacturer.

11
ROUTINE CLEANING OF COIL SURFACES
Periodic cleaning with Totaline®environmentally balanced 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 balanced coil clean-
er as described below. Coil cleaning should be part of the unit’s
regularly 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 balanced coil cleaner is nonflammable,
hypo-allergenic, non-bacterial, and a USDA accepted biodegrad-
able 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 Condenser Coil (50FC 04 units only)
Wash coil with commercial coil cleaner. It is not necessary to re-
move top panel.
Two-Row Condenser Coils (50FC 05-07 units)
Clean coil as follows:
1. Turn off unit power, tag disconnect.
2. Remove all screws from the top panel except the screws
securing the condenser fan to the top panel. See Fig. 15.
Fig. 15 — Location of Screws and Coil Corner Post
3. Lift and rotate the top panel at the condenser fan end and
rotate the panel 90 degrees. Support the top panel so it
remains level while resting on the condenser fan as shown
in Fig. 16.
Fig. 16 — Top Panel Position
4. Remove the compressor access panel to access the lower
coil clip. The condenser coil corner post may also be
removed.
5. Remove the screws from both sides of the upper and lower
coil retaining clips on the hairpin end of the coil tube
sheets. See Fig. 17.
Fig. 17 — Condenser Coil Clips
6. Remove the upper and lower retaining clips.
7. Draw the inner coil inward to separate the coils for cleaning.
8. Insert a spacer (field-supplied) between the tube sheets to
hold the coils apart. See Fig. 18.
9. Clean the outer coil surface to remove surface loaded
fibers or dirt. See “Remove Surface Loaded Fibers” on
page 10 for details.
10. Use a water hose or other suitable equipment to flush
down between the 2 coil sections to remove dirt and
debris. If a coil cleaner is used be sure to rinse the coils
completely before reassembly.
11. Move the inner coil back into position. Reinstall the lower
and upper coil clips. Reinstall the top panel and replace all
screws.
Totaline Environmentally Balanced Coil Cleaner Application
Equipment
• 2-1/2 gallon garden sprayer
• Water rinse with low velocity spray nozzle
Top Panel
Remove screws
from all sides
of top panel
Remove
Screws
Condenser
Fan
Condenser
Coil
Condenser Coil
Corner Post
Center
Post
Compressor
Access Panel
Top Panel
Center
Baffle
Compressor
Access
Panel
Support
(Field-
Supplied)
Coil Clips

12
Fig. 18 — Separating Coil Sections
Totaline Environmentally Balanced 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 finned surfaces with clean water and a
low velocity garden hose, being careful not to bend fins.
4. Mix Totaline environmentally balanced coil cleaner in a
2-1/2 gallon 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 balanced 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 spray-
ing 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 Molex1plug 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.
Evaporator Coil Metering Devices
Three different evaporator coil metering systems are used on
50FC sizes 04-07. 50FC-*04-06 units without the
Humidi-MiZer®option use the Acutrol™system for evaporator
metering. 50FC 07 units with or without the Humidi-MiZer op-
tion use a TXV-distributer system.
Check the unit’s information data plate for Position 6 value, then
compare this value to the Model Number Nomenclature on
page 57 to confirm the unit’s construction.
The metering devices are multiple fixed-bore devices (Acutrol)
swaged into the horizontal outlet tubes from the liquid header, lo-
cated at the entrance to each evaporator coil circuit path. These are
non-adjustable. Service requires replacing the entire liquid header
assembly.
To check for possible blockage of one or more of these metering
devices, jumper R to Y1 without the G terminal jumpered, then
start the compressor and observe the frosting pattern on the face of
the evaporator coil. A frost pattern should develop uniformly
across the face of the coil starting at each horizontal header tube.
Failure to develop frost at an outlet tube can indicate a plugged or
missing orifice.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit
performance 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
airside 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 environmentally balanced coil
cleaner.
102 mm
(4" MAX)
Inner
Coil
Section
Outer
Coil
Section
Condenser
Coil
Center Baffle
Hairpin
End
Top View
Spacer
(Field-Supplied)
1. Third-party trademarks and logos are the property of their respective
owners.
UNIT SIZE HUMIDI-MIZER EVAPORATOR METERING
04-06 NO Acutrol
YES Acutrol and TXV
07 NO TXV
YES TXV

13
THERMOSTATIC EXPANSION VALVE (TXV)
All 50FC 04-06 units equipped with the Humidi-MiZer option and
all 50FC 07 units include TXV control. The TXV is a bi-flow,
bleed port expansion valve with an external equalizer. The TXVs
are specifically designed to operate with Puron®refrigerant. Use
only factory-authorized 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
dependent upon the following:
1. Superheat temperature is sensed by cap tube sensing bulb
on suction tube at outlet of evaporator coil. This tempera-
ture is converted into pressure by refrigerant in the bulb
pushing 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 5/16 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 on page 13.
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.
Fig. 19 — TXV Valve and Sensing Bulb Location
TXV Sensing Bulb
Clamp
Thermostatic
Expansion
Valve (TXV)
Sensing Bulb Insulation Removed for Clarity

14
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 compressor.
These are brass fittings with black plastic caps. The hose connec-
tion 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. 20 — CoreMax1Access Port Assembly
1. Third-party trademarks and logos are the property of their respective owners.
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
This surface provides a metal 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 gauge manifold; remove
liquid from the cylinder, pass it through the metering device at the
gauge set and then pass it into the suction line as a vapor. Do not
remove 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 Cooling Charging Charts, Fig. 21-31, vary refrigerant until
the conditions of the appropriate 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 operat-
ing conditions. Accurate pressure gauge and temperature sensing
device are required. Connect the pressure gauge 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. Indoor-air cfm must be within the normal
operating range of the unit.
EXAMPLE:
Model 50FC-B04
Outdoor Temperature 85°F (29°C)
Suction Pressure 140 psig (965 kPa)
Suction Temperature should be 65°F (16°C)
USING COOLING CHARGING CHARTS
Take the outdoor ambient temperature and read the liquid pressure
gauge. 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, 1-Phase
Fig. 22 — Cooling Charging Chart — 3 Ton, 3-Phase
50FC SIZE DESIGNATION NOMINAL TONS REFERENCE
04 3
05 4
06 5
07 6
–1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 3 Ton
(Single Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55 / 13
45 / 7
48TC005841 REV -
Add Charge if Above the Curve
Remove Charge if Below the Curve
-1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 3 Ton
(3-Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
48TC003182 REV -

16
Fig. 23 — Cooling Charging Chart — 3 Ton with
Hot Gas Reheat (Humidi-MiZer®System) Option
Fig. 24 — Cooling Charging Chart — 4 Ton, 1-Phase
Fig. 25 — Cooling Charging Chart — 4 Ton, 3-Phase
Fig. 26 — Cooling Charging Chart — 4 Ton with
Hot Gas Reheat (Humidi-MiZer®System) Option
Outdoor Coil Leaving Temperature, [°C/°F]
1034 1379 1723 2068 2413 2758 3102 3447 3792 4136
-6.7
4.4
15.5
26.6
37.7
48.8
59.9
20
40
60
80
100
120
140
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure, [psig/Kpa]
3 Ton Std Tier Hot gas Reheat R-410A CHARGING CHART
(Unit must run on Sub-cooling mode)
Remove Charge if Below the Curve
48tc003189 rev. A
Add Charge if Above the Curve
–1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 4 Ton
(Single Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55 / 13
45 / 7
48TC005842 REV -
Add Charge if Above the Curve
Remove Charge if Below the Curve
-1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 4 Ton
(3-Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55 / 13
45 / 7
48TC003183 REV -
1034 1379 1723 2068 2413 2758 3102 3447 3792 4136
-6.7
4.4
15.5
26.6
37.7
48.8
59.9
20
40
60
80
100
120
140
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure, [psig/Kpa]
4 Ton Std Tier Hot gas Reheat R-410A CHARGING CHART
(Unit must run on Sub-cooling mode)
Remove Charge if Below the Curve
48tc003190 rev. A
Add Charge if Above the Curve
Outdoor Coil Leaving Temperature, [°C/°F]

17
Fig. 27 — Cooling Charging Chart — 5 Ton, 1-Phase
Fig. 28 — Cooling Charging Chart — 5 Ton, 3-Phase
Fig. 29 — Cooling Charging Chart — 5 Ton with
Hot Gas Reheat (Humidi-MiZer System) Option
Fig. 30 — Cooling Charging Chart — 6 Ton
–1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 5 Ton
(Single Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55 / 13
45 / 7
48TC005843 REV -
Remove Charge if Below the Curve
Add Charge if Above the Curve
-1.1 1.7 4.5 7.2 10.0 12.8 15.6 18.3 21.1 23.9 26.7 29.5 32.2
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
30 35 40 45 50 55 60 65 70 75 80 85 90
SUCTION PRESSURE [psig / Kpa]
SUCTION LINE TEMPERATURE [°F/°C]
Cooling Charging Chart Std Tier 5 Ton
(3-Phase) R-410A Refrigerant
OUTDOOR
TEMP
°F / C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
48TC003184 REV -
OUTDOOR
TEMP
F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
Outdoor Coil Leaving Temperature, [°C/°F]
1034 1379 1723 2068 2413 2758 3102 3447 3792 4136
-6.7
4.4
15.5
26.6
37.7
48.8
59.9
20
40
60
80
100
120
140
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure, [psig/Kpa]
5 Ton Std Tier Hot gas Reheat R-410A CHARGING CHART
(Unit must run on Sub-cooling mode)
Remove Charge if Below the Curve
48TC003191 rev. A
Add Charge if Above 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 Cooling Charging Chart Std Tier 6 Ton
(Unit must run high stage compressor and
outdoor fan on high speed)
Add Charge if
Above the Curve
Remove Charge if
Below the Curve
48TC003185 REV -

18
Fig. 31 — Cooling Charging Chart — 6 Ton with
Hot Gas Reheat (Humidi-MiZer®System) Option
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.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to
components.
The compressor is in a R-410A 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.
Outdoor Coil Leaving Temperature, [°C/°F]
1034 1379 1723 2068 2413 2758 3102 3447 3792 4136
-6.7
4.4
15.5
26.6
37.7
48.8
59.9
20
40
60
80
100
120
140
150 200 250 300 350 400 450 500 550 600
Compressor Discharge Pressure, [psig/Kpa]
6 Ton Std Tier Hot gas Reheat R-410A CHARGING CHART
(Unit must run on Sub-cooling mode)
Remove Charge if Below the Curve
48TC003192 rev. A
Add Charge if Above the Curve
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-
certified refrigerants could contain contaminates that could
lead to unsafe operating conditions. Use ONLY refrigerants
that conform to AHRI Standard 700.
CAUTION
INSTALLATION SITE DAMAGE
Failure to follow this caution can result in damage to
equipment location site.
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
remove brazed fittings.

19
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
whether or not compressor is rotating in the proper direction:
1. Connect service gauges 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 less than 650 psig. Do not install a suction-line filter
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).
See Fig. 32.
3. Loosen fan hub setscrews.
4. Adjust fan height by pushing fan until it stops on the fan
shaft.
5. Tighten set screw to 60 in.-lb (6.78 Nm).
6. Replace condenser-fan assembly. When replacing the con-
denser-fan assembly follow the screw pattern sequence
shown in Fig. 33. The screws must be replaced in the
sequence shown in the figure.
Fig. 32 — Condenser Fan Adjustment
Fig. 33 — Condenser-Fan Assembly — Screw Pattern Sequence
CAUTION
INSTALLATION SITE DAMAGE
Failure to follow this caution can result in damage to
equipment location site.
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
remove brazed fittings.
1
2
3
4
5
No Screw
(Blank Tab)

20
Troubleshooting Cooling System
Refer to Table 3 for additional troubleshooting topics.
Table 3 — Troubleshooting
SYMPTOM CAUSE SOLUTION
Compressor and Outdoor
Fan Will Not Start
Power failure. Call power company.
Fuse blown or circuit breaker tripped. Replace fuse or reset circuit breaker. Determine root cause.
Defective thermostat, contactor, transformer,
control relay, or capacitor. Replacement component.
Insufficient line voltage. Determine cause and correct.
Incorrect or faulty wiring. Check wiring diagram and rewire correctly.
Thermostat setting too high. Lower thermostat setting below room temperature.
High pressure switch tripped. See problem “Excessive head pressure.”
Low pressure switch tripped. Check system for leaks. Repair as necessary.
Freeze-up protection thermostat tripped. See problem “Suction pressure too low.”
Compressor Will Not Start
but Outdoor Fan Runs
Faulty wiring or loose connections in compressor
circuit. Check wiring and repair or replace.
Compressor motor burned out, seized, or internal
overload open.
Determine cause. Replace compressor or allow enough time for
internal overload to cool and reset.
Defective run/start capacitor, overload, start
relay.
Determine cause. Replace compressor or allow enough time for
internal overload to cool and reset.
One leg of 3-phase power dead. Replace fuse or reset circuit breaker. Determine cause.
Compressor Cycles (Other
Than Normally Satisfying
Thermostat)
Refrigerant overcharge or undercharge. Recover refrigerant, evacuate system, and recharge to nameplate.
Defective compressor. Replace and determine cause.
Insufficient line voltage. Determine cause and correct.
Blocked outdoor coil or dirty air filter. Determine cause and correct.
Defective Run/Start capacitor, overload, start
relay. Determine cause and correct.
Defective thermostat. Replace thermostat.
Faulty outdoor-fan (cooling) or indoor-fan
(heating) motor or capacitor. Replace faulty part.
Restriction in refrigerant system. Locate restriction and remove.
Defective loader plug. Determine cause and replace.
Compressor Operates
Continuously
Dirty air filter. Replaced filter.
Unit undersized for load. Decrease load or increase unit size.
Thermostat set too low (cooling). Reset thermostat.
Low refrigerant charge. Locate leak; repair and recharge.
Air in system. Recover refrigerant, evacuate system, and recharge.
Outdoor coil dirty or restricted. Clean coil or remove restriction.
Compressor Makes
Excessive Noise Compressor rotating in the wrong direction. Reverse the 3-phase power leads as described in Start-Up.
Excessive Head Pressure
Dirty outside. Replace filter.
Dirty outdoor coil (cooling). Clean coil.
Refrigerant overcharged. Recover excess refrigerant.
Air in system. Recover refrigerant, evacuate system, and recharge.
Condensing air restricted or air short-cycling. Determine cause and correct.
Head Pressure Too Low
Low refrigerant charge. Check for leaks; repair and recharge
Compressor scroll plates defective. Replace compressor
Restriction in liquid tube. Remove restriction.
Excessive Suction Pressure
High heat load. Check for source and eliminate.
Compressor scroll plates defective. Replace compressor.
Refrigerant overcharge. Recover excess refrigerant.
Suction Pressure Too Low
Dirty air filter (cooling). Replace filter.
Dirt or heavily iced outdoor coil (heating). Clean outdoor coil. Check defrost cycle operation.
Low refrigerant charge. Check for leaks; repair and recharge.
Metering device or low side restricted Remove source of restriction.
Insufficient indoor airflow (cooling mode). Increase air quantity. Check filter and replace if necessary.
Temperature too low in conditioned area. Reset thermostat.
Field-installed filter drier restricted. Replace.
Outdoor ambient temperature below 40°F
(cooling). Install low-ambient kit.
Outdoor fan motor(s) not operating (heating). Check fan motor operation.