Carrier 50FCQ 04-07 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. 04-53500339-01 Printed in U.S.A. Form 50FCQ-4-7-02SM Pg 1 7-23 Replaces: 50FCQ-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 (Outdoor) . . . . . . . . . . . . . . . . . . . . 10
Evaporator Coil (Indoor) . . . . . . . . . . . . . . . . . . . . . . 10
Condenser Coil Maintenance and Cleaning 
Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . 10
EVAPORATOR COIL . . . . . . . . . . . . . . . . . . . . . . . . . 12
Refrigeration System Components . . . . . . . . . . . . . 12
Evaporator Coil Metering Devices . . . . . . . . . . . . . . 14
THERMOSTATIC EXPANSION VALVE (TXV) . . . . . 14
TXV Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing TXV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Refrigerant System Pressure Access Ports . . . . . . 15
PURON (R-410A) REFRIGERANT . . . . . . . . . . . . . . . 15
Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . . . . . 16
COOLING CHARGING CHARTS . . . . . . . . . . . . . . . . 16
COMPRESSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacing Compressor . . . . . . . . . . . . . . . . . . . . . . . 18
Compressor Rotation . . . . . . . . . . . . . . . . . . . . . . . . 18
Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Condenser-Fan Adjustment . . . . . . . . . . . . . . . . . . . 18
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
COMMERICAL DEFROST CONTROL . . . . . . . . . . . . 22
Reversing Valve Control . . . . . . . . . . . . . . . . . . . . . 23
Compressor Control . . . . . . . . . . . . . . . . . . . . . . . . . 23
Auxiliary (Electric) Heat control . . . . . . . . . . . . . . . . 23
Defrost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
ELECTRIC HEATERS . . . . . . . . . . . . . . . . . . . . . . . . 24
Single Point Boxes and Supplementary Fuses . . . 25
Safety Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Completing Heater Installation . . . . . . . . . . . . . . . . .25
SMOKE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . .26
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Smoke Detector Sensor . . . . . . . . . . . . . . . . . . . . . .26
Smoke Detector Locations . . . . . . . . . . . . . . . . . . . .26
Completing Installation of Return Air Smoke
Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
FIOP Smoke Detector Wiring and Response . . . . .28
SENSOR AND CONTROLLER TESTS . . . . . . . . . . .29
Sensor Alarm Test . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Controller Alarm Test . . . . . . . . . . . . . . . . . . . . . . . .29
Dirty Controller Test . . . . . . . . . . . . . . . . . . . . . . . . .29
Dirty Sensor Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Changing the Dirty Sensor Test . . . . . . . . . . . . . . . .29
Remote Station Test . . . . . . . . . . . . . . . . . . . . . . . . .29
SD-TRM4 Remote Alarm Test Procedure . . . . . . . .30
Remote Test/Reset Station Dirty Sensor Test . . . .30
Dirty Sensor Test Using an SD-TRM4 . . . . . . . . . . .30
Detector Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
PROTECTIVE DEVICES . . . . . . . . . . . . . . . . . . . . . . .32
Compressor Protection . . . . . . . . . . . . . . . . . . . . . . .32
Relief Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Control Circuit, 24-V . . . . . . . . . . . . . . . . . . . . . . . . .32
SYSTEMVU CONTROL SYSTEM . . . . . . . . . . . . . . . .32
SystemVu Interface . . . . . . . . . . . . . . . . . . . . . . . . . .32
Additional SystemVu Installation and
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .32
RTU OPEN CONTROL SYSTEM . . . . . . . . . . . . . . . .34
Sensory/Accessory Installation . . . . . . . . . . . . . . . .34
Additional RTU Open Installation and
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .35
ECONOMIZER SYSTEMS . . . . . . . . . . . . . . . . . . . . .35
EconoMi$er 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
EconoMi$er IV (Field-Installed Accessory) . . . . . . .37
EconoMi$er X (Factory Option) . . . . . . . . . . . . . . . .44
PRE-START-UP/START-UP . . . . . . . . . . . . . . . . . . . .58
START-UP, GENERAL . . . . . . . . . . . . . . . . . . . . . . . .59
Unit Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Additional Installation/Inspection . . . . . . . . . . . . . .59
Return-Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Outdoor-Air Inlet Screens . . . . . . . . . . . . . . . . . . . . .59
Compressor Mounting . . . . . . . . . . . . . . . . . . . . . . .59
Internal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Refrigerant Service Ports . . . . . . . . . . . . . . . . . . . . .59
50FCQ*04-07
Single Package Rooftop Heat Pump
with Puron®(R-410A) Refrigerant
3 to 6 Nominal Tons

2
Compressor Rotation . . . . . . . . . . . . . . . . . . . . . . . . 59
Refrigerant Service Ports . . . . . . . . . . . . . . . . . . . . . 59
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Ventilation (Continuous Fan) . . . . . . . . . . . . . . . . . . 60
FASTENER TORQUE VALUES . . . . . . . . . . . . . . . . . 60
START-UP, RTU OPEN CONTROLS . . . . . . . . . . . . . 60
START-UP, SYSTEMVU CONTROLS . . . . . . . . . . . . 60
APPENDIX A — MODEL NUMBER 
NOMENCLATURE. . . . . . . . . . . . . . . . . . . . . . . . . . 61
APPENDIX B — PHYSICAL DATA. . . . . . . . . . . . . . . 62
APPENDIX C — FAN PERFORMANCE . . . . . . . . . . . 64
APPENDIX D — WIRING DIAGRAMS . . . . . . . . . . . . 93
APPENDIX E — LOW AMBIENT CONTROL 
SENSOR LOCATION . . . . . . . . . . . . . . . . . . . . . . 109
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 per-
form the basic maintenance functions of replacing filters. Trained
service personnel should perform all other operations.
When working on air-conditioning equipment, observe precau-
tions 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 extinguishers available for all brazing opera-
tions.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for brazing operations. Have fire extinguisher
available. Read these instructions thoroughly and follow all warn-
ings or cautions attached to the unit. Consult local building codes
and National Electrical Code (NEC) for special requirements.
Recognize safety information. This is the safety ALERT symbol
. When you see this symbol on the unit and in instructions or
manuals, be aware of the potential for physical injury hazards.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety ALERT symbol.
DANGER indicates a hazardous situation which, if not avoided,
will result in death or severe personal injury. WARNING indi-
cates a hazardous situation which, if not avoided, could result in
death or personal injury. CAUTION indicates a hazardous situa-
tion which, if not avoided, could result in minor to moderate injury
or product and property damage. IMPORTANT is used to ad-
dress practices not related to physical injury. 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 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.
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 electri-
cal 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 2, 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.)
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.
Fig. 4 — Screens Installed on Outdoor-Air Hood
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 50FCQ units have the EcoBlue™ direct drive vane axial fan
system. The fan is driven by an ECM motor with speed that is user
set through the Unit Control Board (UCB). Speeds are fully con-
figurable from 40% to 100% of the motor’s maximum speed. See
Fig. 5 and 6.
Fig. 5 — Direct-Drive Supply Fan Assembly
Fig. 6 — ECM Motor Plug Connectors
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.
Electrical shock and rotating equipment could cause severe
injury.
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
10 vdc Source
0–10 vdc Signal

5
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 the motor’s maximum rpm.
SELECTING FAN SPEED
All units come factory set for 9.0 vdc or approximately 90% 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 la-
bel may already include the field setting if unit was previously in-
stalled. Check the box on the lower half of the label to see if the
field voltage 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
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 Fan
Speed Set Up label, add accessory vdc to base unit vdc in
upper portion of label. For electric heaters use only
1 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 50FCQ low fan speed for
3 to 5 ton 50FCQ units, set both DIP switches to “OFF” (0). For
6 ton 50FCQ 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
LOW SPEED PERCENTAGE OF USER SET
FAN SPEED
DIP1 DIP2
0 0 100%
0 1 88%
1 0 75%
1 1 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.
r
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 2 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
Overheated Manual
The motor will stop in the event the
motor overheats. In this case there has
to be a manual restart.
Power Module
Overheated Manual
The motor will stop in the event the
electronics overheat. 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.
50FCQ UNIT VOLTAGE MOTOR VOLTAGE MINIMUM-
MAXIUMUM VOLTS
208/230 230 190-250
460 230 210-250
575 460 420-500
4
2
1
3

9
Disassembling Motor and Fan Assembly
See Fig. 12.
1. Remove 6 screws from retaining rings in the top of the fan
rotor.
2. Remove rotor from motor.
3. Remove 4 screws connecting motor to stator flange.
4. Remove stator from motor.
5. If required, remove stator limit switch on aluminum stator.
6. Remove 3 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 3 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 2 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 4 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 2 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) 2 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 50FCQ*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 (Outdoor)
The condenser coil is fabricated with round tube copper hairpins
and plate fins of various materials and/or coatings (see Model
Number Nomenclature on page 61 to identify the materials pro-
vided in this unit). The coil may be one-row or composite-type
2-row. Composite 2-row coils are 2 single-row coils fabricated
with a single return bend end tubesheet.
Evaporator Coil (Indoor)
The evaporator coil is traditional round-tube, plate-fin technology.
Tube and fin construction is of various optional materials and
coatings (see Model Number Nomenclature on page 61). Coils are
multiple-row.
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.
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
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
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.
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.
Fig. 18 — Separating Coil Sections
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
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
4" max.
(102 mm)
Inner
Coil
Section
Outer
Coil
Section
Condenser
Coil
Center Baffle
Hairpin
End
Top View
Spacer
(Field-Supplied)

12
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
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 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®1 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.
Refrigeration System Components
Each heat pump refrigeration system includes a compressor, accu-
mulator, reversing valve, dual-function outdoor coil with vapor
header check valve, cooling liquid line with a filter drier and a
check valve, dual-function indoor coil with a vapor header check
valve, and heating liquid line with a check valve and a strainer.
Unit sizes 04-06 have a single compressor-circuit. See Fig. 19 for
one-stage cooling units (3 to 5 tons) or Fig. 20 for 2-stage cooling
units (6 ton) and Tables 3-5 for typical unit piping schematic.
Dual-function outdoor and indoor coils are designed to provide
parallel coil circuits during evaporator-function operation and con-
verging coil circuits during the condenser-function operation.
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.
1. Third-party trademarks and logos are the property of their respective
owners.

13
Fig. 19 — 50FCQ*04-06 Piping Schematic — One-Stage Cooling
Fig. 20 — 50FCQ*07 Piping Schematic — Two-Stage Cooling, Single Circuit
B
Acutrol DFT 1
Cooling Liquid Line
A
D
Outdoor Coil Indoor Coil
C
Heating Mode Liquid Line
Strainer
Filter
Drier
LPS/LOC
Accurater
Acutrol
COMPRESSOR
ACCUMULATOR
HPS
B
Acutrol DFT 1
Cooling Liquid Line
A
D
Outdoor Coil Indoor Coil
C
Heating Mode Liquid Line
Strainer
Filter
Drier LPS/LOC
Accurater
TXV
COMPRESSOR
ACCUMULATOR
HPS

14
Evaporator Coil Metering Devices
Two different evaporator coil metering systems are used on
50FCQ sizes 04-07. 50FCQ*04-06 units use the Acutrol system
for evaporator metering. 50FCQ*07 units 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
61 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.
THERMOSTATIC EXPANSION VALVE (TXV)
All 50FCQ*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
(R-410A). 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/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. 21 on page 15.
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.
Table 3 — Cooling Mode (each circuit)
COMPONENTS STATUS/POSITION
Reversing Valve Energized
Check Valve A Closed
Check Valve B Open
Check Valve C Closed
Check Valve D Open
Table 4 — Heating Mode (each circuit)
COMPONENTS STATUS/POSITION
Reversing Valve De-energized
Check Valve A Open
Check Valve B Closed
Check Valve C Open
Check Valve D Closed
Table 5 — Defrost Mode
COMPONENTS STATUS/POSITION
Defrost Thermostat Closed
Outdoor Fan(s) Off
Reversing Valve Energized
Check Valve A Closed
Check Valve B Open
Check Valve C Closed
Check Valve D Open
UNIT SIZE EVAPORATOR METERING
04-06 Acutrol
07 TXV

15
Fig. 21 — TXV Valve and Sensing Bulb Location
Refrigerant System Pressure Access Ports
There are 2 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 connection fit-
tings are standard 1/4 in. SAE male flare couplings.
The brass fittings are 2-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. 22. 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.
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.
Fig. 22 — CoreMax®1 Access Port Assembly
TXV Sensing Bulb
Clamp
Thermostatic
Expansion
Valve (TXV)
NOTE: Sensing bulb insulation removed for clarity.
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)

16
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. 23-27, 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 50FCQA04
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. 23 — Cooling Charging Chart — 3 Ton,
50FCQA04
Fig. 24 — Cooling Charging Chart — 4 Ton,
50FCQC05
50FCQ SIZE DESIGNATION NOMINAL TONS REFERENCE
04 3
05 4
06 5
07 6
48TC003781 A
SUCTION LINE TEMPERATURE [°F/°C]
–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
30 35 40 45 50 55 60 65 70 75 80 85 90
]apK/gisp[ERUSSERPNOITCUS
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180 (Unit must be operated in cooling mode)
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
Cooling Charging Chart Std 3 Ton Heat Pump
R-410A Refrigerant
48TC005844 -
SUCTION LINE TEMPERATURE [°F/°C]
–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
30 35 40 45 50 55 60 65 70 75 80 85 90
]a
pK/gisp[E
RUS
SERPNOITCUS
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
Cooling Charging Chart Std 4 Ton Heat Pump (Single Phase)
R-410A Refrigerant
(Unit must be operated in cooling mode)
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
Add Charge if Above the Curve
Remove Charge if Below the Curve

17
Fig. 25 — Cooling Charging Chart — 4 Ton,
50FCQA05
Fig. 26 — Cooling Charging Chart — 5 Ton,
50FCQA06
Fig. 27 — Cooling Charging Chart — 6 Ton,
50FCQM07
COMPRESSOR
Lubrication
The compressor is charged with the correct amount of oil at the
factory.
48TC003782 A
SUCTION LINE TEMPERATURE [°F/°C]
–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
30 35 40 45 50 55 60 65 70 75 80 85 90
]a
p
K/gisp[E
R
US
S
ERP
NO
I
T
CU
S
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180 (Unit must be operated in cooling mode)
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
Cooling Charging Chart Std 4 Ton Heat Pump (Three Phase)
R-410A Refrigerant
48TC003783 A
SUCTION LINE TEMPERATURE [°F/°C]
-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
30 35 40 45 50 55 60 65 70 75 80 85 90
]apK/gisp[ERUSSERPNOITCUS
551
620
689
758
827
896
965
1034
1103
1172
1241
80
90
100
110
120
130
140
150
160
170
180
(Unit must be operated in cooling mode)
OUTDOOR
TEMP
°F / °C
115 / 46
105 / 41
95 / 35
85 / 29
75 / 24
65 / 18
55/ 13
45/ 7
Cooling Charging Chart Std 5 Ton Heat Pump
R-410A Refrigerant
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.
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.
(Unit must run in cooling mode, on high stage
compressors & outdoor fan on high speed)
Outdoor Coil Leaving Temperature, [°C/°F]
-6.7
4.4
15.5
26.6
37.7
48.8
59.9
20
40
60
80
100
120
140
Add Charge if Above the Curve
Remove Charge if Below the Curve
48TC003784 A
Compressor Discharge Pressure, [psig/Kpa]
1034 1379 1723 2068 2413 2758 3102 3447 3792 4136
150 200 250 300 350 400 450 500 550 600
Cooling Charging Chart Std 6 Ton Heat Pump
R-410A Refrigerant

18
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
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 2 of the 3 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 (4482 kPa).
Condenser-Fan Adjustment
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and fan).
See Fig. 28.
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
condenser-fan assembly follow the screw pattern sequence
shown in Fig. 29. The screws must be replaced in the
sequence shown in the figure.
Fig. 28 — Condenser Fan Adjustment
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.
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
rotating 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.
CAUTION
EQUIPMENT DAMAGE
Failure to follow this caution can result in equipment damage.
Do not install a suction-line filter drier in liquid line. A liquid-
line filter drier designed for use with R-410A refrigerant is
required on every unit.

19
Fig. 29 — Condenser-Fan Assembly — Screw Pattern Sequence
1
2
3
4
5
No Screw
(Blank Tab)

20
Troubleshooting Cooling System
Refer to Table 6 for additional troubleshooting topics.
Table 6 — 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, or 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. Replace 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.