Carrier 38AUQ 07-12 Series Dimensions and installation guide

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53380047-01 Printed in U.S.A. Form 38AUQ-7-12-04SI Pg 1 1-23 Replaces: 38AUQ-7-12-03SI
Installation, Start-Up and Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 2
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Rated Indoor Airflow (cfm) . . . . . . . . . . . . . . . . . . . . . 2
INSTALLATION GUIDELINE . . . . . . . . . . . . . . . . . . . . 2
Replacement /Retrofit — R-22 to Puron Refrigerant . . 2
•ACIDTEST
• EVALUATE EXISTING REFRIGERANT PIPING
• INSTALLATION
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Jobsite Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Step 1 — Plan for Unit Location . . . . . . . . . . . . . . . . 7
Step 2 — Complete Pre-Installation Checks . . . . . . . 7
• CHECK UNIT ELECTRIC CHARACTERISTIC
• UNCRATE UNIT
• INSPECT SHIPMENT
• CONSIDER SYSTEM REQUIREMENTS
Step 3 — Prepare Unit Mounting Support . . . . . . . . 8
• SLAB MOUNT
Step 4 — Rig and Mount the Unit . . . . . . . . . . . . . . . 8
•RIGGING
Step 5 — Complete Refrigerant Piping 
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Check Vertical Separation . . . . . . . . . . . . . . . . . . . . . 9
Provide Safety Relief . . . . . . . . . . . . . . . . . . . . . . . . . 9
Refrigerant Line Sizing . . . . . . . . . . . . . . . . . . . . . . . . 9
Risers in Heat Pump Piping Systems . . . . . . . . . . . . 9
• LIQUID LINE RISER
• VAPOR LINE RISER
Install Filter Drier and Moisture Indicator . . . . . . . . . 9
Install Liquid Line Solenoid Valves . . . . . . . . . . . . . 10
Make Piping Connections . . . . . . . . . . . . . . . . . . . . 10
Evacuation/Dehydration . . . . . . . . . . . . . . . . . . . . . . 10
Preliminary Charge . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Step 6 — Install Accessories . . . . . . . . . . . . . . . . . . 11
Step 7 — Complete Electrical Connections . . . . . . 11
• FIELD POWER SUPPLY
• UNITS WITHOUT FACTORY-INSTALLED
DISCONNECT
• UNITS WITH FACTORY-INSTALLED DISCONNECT
• ALL UNITS
• VOLTAGE AND CURRENT BALANCE
Convenience Outlets . . . . . . . . . . . . . . . . . . . . . . . . 12
Installing Weatherproof Cover . . . . . . . . . . . . . . . . . 13
• FIELD CONTROL WIRING
• THERMOSTAT
• EXTERNAL CONTROL DEVICES
Step 8 — Wind Baffles for Low Ambient Control . . 16
PRE-START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Turn On Crankcase Heater . . . . . . . . . . . . . . . . . . . .16
Preliminary Charge . . . . . . . . . . . . . . . . . . . . . . . . . .16
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
38AUQ Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
• PRELIMINARY CHECKS
• COMPRESSOR ROTATION
• COMPRESSOR OVERLOAD
• ADVANCED SCROLL TEMPERATURE PROTECTION
(ASTP)
•STARTUNIT
• ADJUST REFRIGERANT CHARGE
•FINALCHECKS
OPERATING SEQUENCE . . . . . . . . . . . . . . . . . . . . .20
Base Unit Controls . . . . . . . . . . . . . . . . . . . . . . . . . . .20
• INDOOR (SUPPLY) FAN
• COOLING, UNIT WITHOUT ECONOMIZER —
TWO-STAGE UNITS
• FAN CYCLING
• COOLING, UNIT WITH ECONOMIZER
• HEATING
• DEFROST CYCLE
• SUPPLEMENTAL HEAT/EMERGENCY HEAT
• COOLING AND HEATING SHUTDOWN
ROUTINE SYSTEM MAINTENANCE . . . . . . . . . . . . .22
Quarterly Inspection 
(and 30 days after initial start) . . . . . . . . . . . . . . .22
• INDOOR SECTION
• OUTDOOR SECTION
• ECONOMIZER OR OUTSIDE AIR DAMPER
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Quarterly Inspection 
(and 30 days after initial start) . . . . . . . . . . . . . . .22
• INDOOR SECTION
Seasonal Maintenance . . . . . . . . . . . . . . . . . . . . . . .22
• AIR CONDITIONING
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Refrigeration System . . . . . . . . . . . . . . . . . . . . . . . . .23
•COMPRESSOROIL
• SERVICING SYSTEMS ON ROOFS WITH
SYNTHETIC MATERIALS
• LIQUID LINE FILTER DRIER
• FIELD REFRIGERANT ACCESS PORTS
• OUTDOOR COIL METERING DEVICES
• REFRIGERANT SYSTEM PRESSURE ACCESS PORTS
Compressor Protection . . . . . . . . . . . . . . . . . . . . . . .26
• COMPRESSOR OVERCURRENT
• COMPRESSOR OVERTEMPERATURE PROTECTION
(IP)
• CRANKCASE HEATER
• HIGH PRESSURE SWITCH
• LOSS OF CHARGE SWITCH
• OUTDOOR FAN MOTOR PROTECTION
• CONTROL CIRCUIT, 24-V
38AUQ*07-12
Heat Pump Condensing Units
with Puron®Refrigerant

2
Commercial Defrost Control . . . . . . . . . . . . . . . . . . . 26
• REVERSING VALVE CONTROL
• COMPRESSOR CONTROL
•DEFROST
• DEFROST THERMOSTAT
• DEFROST SPEEDUP FUNCTIONS
COMFORT ALERT DIAGNOSTIC MODULE . . . . . . . 30
Outdoor Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
•FANMOTORS
• COMPRESSOR
Outdoor Coil Maintenance and Cleaning
Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . 32
• REMOVE SURFACE LOADED FIBERS
• PERIODIC CLEAN WATER RINSE
• ROUTINE CLEANING OF INDOOR COIL SURFACES
Service Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
FASTENER TORQUE VALUES . . . . . . . . . . . . . . . . . 34
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . 35
APPENDIX A — AIR CONDITIONER AND HEAT
PUMP WITH PURON®—
QUICK REFERENCE GUIDE . . . . . . . . . . . . . . . . . 36
APPENDIX B — WIRING DIAGRAM LIST . . . . . . . . . 36
APPENDIX C — LOW AMBIENT OPTION —
FACTORY INSTALLED . . . . . . . . . . . . . . . . . . . . . 44
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, mainte-
nance, or use can cause explosion, fire, electrical shock or other
conditions which may cause personal injury or property damage.
Consult a qualified installer, service agency, or your distributor or
branch for information or assistance. The qualified installer or
agency must use factory-authorized kits or accessories when mod-
ifying this product. Refer to the individual instructions package.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloths for brazing operations and have a fire extin-
guisher available. Read these instructions thoroughly and follow
all warnings or cautions attached to the unit. Consult local build-
ing codes and appropriate national electrical codes (in USA,
ANSI/NFPA70, National Electrical Code (NEC); in Canada, CSA
C22.1) for special requirements.
It is important to recognize safety information. This is the safety-
alert symbol . When you see this symbol on the unit and in in-
structions or manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
GENERAL
See Fig. 1for unit dimensions. For physical data, see Tables 2-3.
For model number nomenclature, see Fig. 2. For date of unit man-
ufacture, see Fig. 3.
Rated Indoor Airflow (cfm)
Table 1below lists the rated indoor airflow used for the AHRI ef-
ficiency rating for the units covered in this document.
INSTALLATION GUIDELINE
Replacement /Retrofit — R-22 to Puron Refrigerant
Split system heat pumps are intended to be installed with match-
ing indoor sections only. The 38AUQ heat pump outdoor units are
matched only with same-size 40RFQ indoor sections. Existing
R-22 indoor coils cannot be converted to Puron®R-410A heat
pump duty. Only the existing refrigerant piping is a candidate for
retrofit use.
ACID TEST
If the existing system is being replaced because of a compressor
electrical failure, assume acid is in system. If system is being re-
placed for any other reason, use an approved acid test kit to deter-
mine acid level. If even low levels of acid are detected, install a
100 percent activated alumina suction line filter drier in addition to
the replacement liquid-line filter drier. Operate this system in
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal injury or
death.
Before performing service or maintenance operations on unit,
turn off main power switch to unit and install lock(s) and lock-
out tag(s). Ensure electrical service to rooftop unit agrees with
voltage and amperage listed on the unit rating plate. Unit may
have more than one power switch.
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron®(R-410A) refrigerant systems operate at higher pres-
sures than standard R-22 systems. Do not use R-22 service
equipment or components on Puron refrigerant equipment.
WARNING
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could cause personal injury or
death.
Relieve pressure and recover all refrigerant before system
repair or final unit disposal.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from
refrigerants and oils.
CAUTION
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care and
wear appropriate protective clothing, safety glasses and gloves
when handling parts and servicing 38AUQ units.
Table 1 — 38AUQ with 40RFQ
MODEL NUMBERS FULL LOAD AIRFLOW (cfm)
38AUQD/E07 - 40RFQ*07 2400
38AUQM/N08 - 40RFQ*08 3000
38AUQD/E12 - 40RFQ*12 3000

3
COOLING ONLY. Remove the suction line filter drier as soon as
possible, with a maximum of 72 hours of operation.
Recommendation: Install a ball valve in the liquid line at the filter
drier location when installing a suction filter in the suction line.
EVALUATE EXISTING REFRIGERANT PIPING
Reuse of existing refrigerant piping involves three issues: quality
(strength) of existing tubing, cleanliness and tube size. R-410A
operates at pressures that are 50 to 70% higher than the operating
pressures in R-22 systems. It is important that the existing piping
set be in excellent physical condition to be considered suitable for
re-use with R-410A. If the physical condition of the existing pip-
ing set is not excellent, then remove the existing piping and re-
place with new piping. Refer to Step 5 for a discussion on select-
ing pipe sizes for these 38AUQ heat pumps; refer to Table 4for
recommended pipe sizes.
If the existing piping set is suitable for re-use with R-410A based
on its condition, determine the relative locations and elevation
differences between outdoor section (38AUQ) and indoor section
(40RFQ) and then check the sizes of the existing lines against the
recommended pipe sizes in Table 4and the MAXIMUM vapor
riser pipe size use data in Table 5. Do not use pipe sizes that ex-
ceed these maximum vapor riser sizes as oil return at part load
conditions in vertical rises may be an issue. Replace any riser sec-
tions with reduced pipe sizes if existing pipe sizes exceed these
maximum tube size limits.
INSTALLATION
1. Remove the existing evaporator coil or fan coil and install the
replacement coil.
2. Drain oil from low points and traps in vapor line tubing if
they were not replaced.
3. Remove the existing outdoor unit. Install the new outdoor
unit according to these installation instructions.
4. Flush the interconnection piping system with dry Nitrogen to
eliminate as much trace of mineral oil as possible.
5. Install the factory-supplied liquid-line filter drier at the indoor
coil just upstream of the TXV.
6. If required, install a 100% activated alumina suction line filter
drier at the outdoor unit.
7. Evacuate and charge the system according to the instructions
in this installation manual.
8. Operate the system for 10 hr. In COOLING MODE ONLY.
Monitor the pressure drop across the suction line filter drier.
If pressure drop exceeds 3 psig (21 kPa), replace suction-line
and liquid-line filter driers. Be sure to purge system with dry
nitrogen and evacuate when replacing filter driers. Continue
to monitor the pressure drop across suction-line filter drier.
Repeat filter changes is necessary. Never leave suction-line
filter drier in system longer than 72 hours (actual time).
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage
or improper operation.
Never install suction-line filter drier in the liquid-line of a
Puron®system.

4
Fig. 1 — 38AUQ*07-12 Unit Dimensions

5
Table 2 — Physical Data — 38AUQ*07-12 Units — 60 Hz English
UNIT 38AUQD/E07 38AUQM/N08 38AUQD/E12
Nominal Capacity (tons) 67.510
Operating Weights (lb)
Aluminum-Fin Coils 444 523 575
Refrigeration Systema
NOTE(S):
a. Unit is factory-supplied with partial charge only.
R-410A R-410A R-410A
No. Circuits / No. Comp. / Type 1 / 1 / Scroll 1 / 1 / Scroll 1 / 1 / Scroll
Shipping Charge A/B (lb) 9.0 Puron 9.0 Puron 9.0 Puron
System Charge with Fan Coil A/B (lb)b
b. Approximate system charge with 25 ft piping of sizes indicated with matched 40RFQ.
18 26.2 27
Metering Device Acutrol™c
c. Third-party trademarks and logos are the property of their respective owners.
Acutrol™Acutrol™
High-Press. Trip / Reset (psig) 630 / 505 630 / 505 630 / 505
Low-Press. Trip / Reset (psig) 27 / 44 27 / 44 27 / 44
Compressor
Oil Charge A/B (oz) 38 54 38 / 38
Speed (rpm) 3500 3500 3500
Outdoor Coil
Material Al/Cu Al/Cu Al/Cu
Coil Type RTPF RTPF RTPF
Rows / FPI 2 / 17 2 / 17 2 / 17
Total Face Area (ft2)17.5 28.1 28.1
Outdoor fan / motor
Qty / Motor Drive Type 2 / Direct 2 / Direct 2 / Direct
Motor HP / RPM 1/4 / 1100 1/4 / 1100 1/4 / 1100
Fan Diameter (in) 22 22 22
Nominal Airflow (cfm) 6,000 6,000 6,000
Watts (total) 610 610 610
Piping Connections
Qty / Vapor (in. ODS) 1 / 1-1/8 1 / 1-1/8 1 / 1-3/8
Qty / Liquid (in. ODS) 1 / 3/8 1 / 1/2 1 / 1/2
Table 3 — Physical Data — 38AUQ*07-12 Units — 60 Hz SI
UNIT 38AUQD/E07 38AUQM/N08 38AUQD/E12
Nominal Capacity (kW) 21.1 26.4 35.1
Operating Weights (kg)
Aluminum-Fin Coils 201 237 261
Refrigeration Systema
NOTE(S):
a. Unit is factory-supplied with partial charge only.
R-410A R-410A R-410A
No. Circuits / No. Comp. / Type 1 / 1 / Scroll 1 / 1 / Scroll 1 / 1 / Scroll
Shipping Charge A/B (kg) 4.1 Puron 4.1 Puron 4.1 Puron
System Charge with Fan Coil A/B (kg)b
b. Approximate system charge with 25 ft (7.62 m) piping of sizes indicated with matched 40RFQ.
8.2 11.9 12.2
Metering Device Acutrol™Acutrol™Acutrol™
High-Press. Trip / Reset (kPa) 4344 / 3482 4344 / 3482 4344 / 3482
Low-Press. Trip / Reset (kPa) 186 / 303 186 / 303 186 / 303
Compressor
Oil Charge A/B (L) 1.1 1.6 1.1 / 1.1
Speed (r/s) 367 367 367
Outdoor Coil
Material Al/Cu Al/Cu Al/Cu
Coil Type RTPF RTPF RTPF
Rows / FPM 2 / 0.4 2 / 0.4 2 / 0.4
Total Face Area (sq. m) 1.6 2.6 2.6
Outdoor fan / motor
Qty / Motor Drive Type 2 / Direct 2 / Direct 2 / Direct
Motor HP / r/s 1/4 / 115 1/4 / 115 1/4 / 115
Fan Diameter (mm) 558.8 558.8 558.8
Nominal Airflow (l/s) 2831.7 2831.7 2831.7
Watts (total) 610 610 610
Piping Connections
Qty / Vapor (mm ODS) 1 / 28.6 1 / 28.6 1 / 34.9
Qty / Liquid (mm ODS) 1 / 9.5 1 / 12.7 1 / 12.7
LEGEND
ODS — Outside Diameter Sweat (socket)

6
Fig. 2 — Model Number Nomenclature
Fig. 3 — Serial Number Nomenclature
Model Type
38AU = Carrier Condensing Unit
Puron®R-410A Refrigerant
Heat Pump
Q = Heat Pump
Refrigerant Options¹
D = Single Circuit / 2-Stage2
E = Single Circuit / 2-Stage with Low Ambient2
M = Single Circuit / 2-Stage2
N = Single Circuit / 2-Stage with Low Ambient3
Nominal Tonnage
07 = 6 Tons
08 = 7.5 Tons
12 = 10 Tons
Not Used
A = Not Used
Not Used
0 = Not Used
123456789101112131415161718
Packaging
0=Standard
1=LTL
Electrical Options
A = None
C = Non-Fused Disconnect
Service Options
0=None
1 = Un-powered Convenience Outlet
2 = Powered Convenience Outlet
Not Used
A = Not Used
Not Used
- = Not Used
Voltage
1 = 575-3-60
5 = 208/230-3-60
6 = 460-3-60
Coil Options (RTPF)
A= Al/Cu
B = Precoat (Al/Cu)
C = E-Coat (Al/Cu)
M= Al/Cu with Louvered Hail Guard
N = Precoat (Al/Cu) with Louvered Hail Guard
P = E-Coat (Al/Cu) with Louvered Hail Guard
Base Unit Controls
0 = Standard Electro-Mechanical Controls
38AUQE1 2A0A5- 0A0A0
1
All units meet Department of Energy 2023
IEER requirements.
2
38AUQ 07/12 models only.
3
38AUQ 08 models only.
0522912345
12345678910
DESIGNATES
Week of manufacture (fiscal calendar)
Year of manufacture (“23” = 2023)
Manufacturing location
Sequence number
POSITION
1−2
3−4
5
6−10
POSITION NUMBER
TYPICAL

7
INSTALLATION
Jobsite Survey
Complete the following checks before installation.
1. Consult local building codes and the NEC (National Electri-
cal Code) ANSI/NFPA 70 for special installation
requirements.
2. Determine unit location (from project plans) or select unit
location.
3. Check for possible overhead obstructions which may inter-
fere with unit lifting or rigging.
Step 1 — Plan for Unit Location
Select a location for the unit and its support system (pad, rails or
other) that provides for the minimum clearances required for
safety. This includes the clearance to combustible surfaces, unit
performance and service access below, around and above unit as
specified in unit drawings. See Fig. 4.
Select a unit mounting system that provides adequate height to al-
low for removal and disposal of frost and ice that will form during
the heating-defrost mode.
NOTE: Consider also the effect of adjacent units on airflow per-
formance and control box safety clearance.
Do not install the outdoor unit in an area where fresh air supply to
the outdoor coil may be restricted or when recirculation from the
condenser fan discharge is possible. Do not locate the unit in a
well or next to high walls.
Evaluate the path and required line length for interconnecting re-
frigeration piping, including vapor riser requirements and liquid
line lift; a heat pump system will have one of each type in opposite
modes. Relocate sections to minimize the length of interconnect-
ing tubing.
Although unit is weatherproof, avoid locations that permit water
from higher level runoff and overhangs to fall onto the unit.
Fig. 4 — Service Clearance Dimensional Drawing
Step 2 — Complete Pre-Installation Checks
CHECK UNIT ELECTRIC CHARACTERISTIC
Confirm before installation of unit that voltage, amperage and cir-
cuit protection requirements listed on unit data plate agree with
power supply provided.
UNCRATE UNIT
Remove unit packaging except for the top skid assembly, which
should be left in place until after the unit is rigged into its final
location.
INSPECT SHIPMENT
File a claim with shipping company if the shipment is damaged or
incomplete.
CONSIDER SYSTEM REQUIREMENTS
• Consult local building codes and National Electrical Code
(NEC, U.S.A.) for special installation requirements.
• Allow sufficient space for airflow clearance, wiring, re-
frigerant piping, and servicing unit. See Fig. 1for unit di-
mensions and weight distribution data.
• Locate the unit so that the outdoor coil (condenser) airflow
is unrestricted on all sides and above.
• The unit may be mounted on a level pad directly on the
base channels or mounted on raised pads at support points.
See Tables 2and 3for unit operating weights. See Fig. 1
for weight distribution based on recommended support
points.
NOTE: If vibration isolators are required for a particular installa-
tion, use the data in Fig. 1to make the proper selection.
IMPORTANT: DO NOT BURY REFRIGERATION LINES.
REAR:
Min 18" (457 mm)
required for service
RIGHT:
Min 18" (457 mm)
required for service
LEFT:
Min 18" (457 mm)
required for service
FRONT:
42” (1067 mm)
required for service
NOTE: Observe requirements for 39" (914 mm) operating
clearance on either Left or Rear coil opening.

8
Step 3 — Prepare Unit Mounting Support
SLAB MOUNT
Provide a level concrete slab that extends a minimum of 6 in.
(150 mm) beyond unit cabinet. Install a gravel apron in front of
condenser coil air inlet to prevent grass and foliage from obstruct-
ing airflow.
Step 4 — Rig and Mount the Unit
RIGGING
These units are designed for overhead rigging. Refer to the rigging
label for preferred rigging method. Spreader bars are not required
if top crating is left on the unit. All panels must be in place when
rigging. As further protection for coil faces, plywood sheets may
be placed against the sides of the unit, behind cables. Run cables
to a central suspension point so that the angle from the horizontal
is not less than 45 degrees. Raise and set the unit down carefully.
If it is necessary to roll the unit into position, mount the unit on
longitudinal rails, using a minimum of 3 rollers. Apply force to the
rails, not the unit. If the unit is to be skidded into position, place it
on a large pad and drag it by the pad. Do not apply any force to the
unit.
Raise from above to lift the unit from the rails or pad when unit is
in its final position.
After the unit is in position, remove all shipping materials and top
crating.
Step 5 — Complete Refrigerant Piping 
Connections
Refrigerant lines must be carefully designed and constructed to
ensure equipment reliability and efficiency. Line length, pressure
drop, compressor oil return, and vertical separation are several of
the design criteria that must be evaluated. See Table 4.
IMPORTANT: Do not bury refrigerant piping underground.
IMPORTANT: A refrigerant receiver is not provided with
the unit. Do not install a receiver.
Table 4 — 38AUQ*07-12 Piping Recommendations (Single-Circuit Unit)a
NOTE(S):
a. For applications with linear length greater than 100 ft (30.5 m), contact your local Carrier representative.
R-410A EQUIVALENT LENGTH (ft)
Model Nominal
Capacity
Length Linear 0-24 25-49 50-74 75-100
Length Equiv 0-37 38-74 75-112 113-150
38AUQ*07
Liquid Line (in.) 3/8 3/8 3/8 1/2 3/8 1/2
Max Lift Cool 25 50 48 75 39 100
Max Lift Heat 25 50 48 60 31 60
Suction Line (in.) 7/8 7/8 1-1/8 1-1/8
Charge (lb) 17.8 18.8 20.3 22.6 21.4 24.5
38AUQ*08
Liquid Line (in.) 1/2 1/2 1/2 1/2
Max Lift Cool 25 50 75 100
Max Lift Heat 25 50 50 60
Suction Line (in.) 7/8 1-1/8 1-1/8 1-1/8 1-1/8
Charge (lb) 23.9 26.0 27.9 29.8
38AUQ*12
Liquid Line (in.) 1/2 1/2 1/2 1/2 5/8
Max Lift Cool 25 50 75 85 100
Max Lift Heat 25 50 60 60
Suction Line (in.) 7/8 1-1/8 1-1/8 1-1/8 1-1/8 1-3/8
Charge (lb) 26.8 28.8 30.7 33.4 37.2
LEGEND
Length Equiv — Equivalent tubing length, including effects of refrigeration
specialties devices
Liquid Line — Tubing size, inches OD
Max Lift Cool — Maximum liquid lift at maximum permitted liquid line pressure
drop Indoor unit ABOVE outdoor unit
Max Lift Heat — Maximum liquid lift at maximum permitted liquid line pressure
drop Indoor unit BELOW outdoor unit
Vapor Line — Tube size, inches OD
Charge — Charge Quantity, lb. Calculated for both liquid line sizes (where
applicable), but only with large suction line size (where
applicable)

9
Check Vertical Separation
If there is any vertical separation between the indoor and outdoor
units, check to ensure that the separation is within allowable lim-
its. Relocate equipment if necessary.
Provide Safety Relief
If local codes dictate an additional safety relief device, purchase
locally and install locally. Installation will require the recovery of
the factory shipping charge before the factory tubing can be cut
and the supplemental relief device is installed.
Refrigerant Line Sizing
Consider the length of the piping required between the outdoor
and indoor units. The maximum allowable line length is 100 ft
(30.5 m). See Table 4. Refrigerant vapor piping should be
insulated.
Risers in Heat Pump Piping Systems
Elevation differences between the outdoor unit and the indoor unit
in heat pump systems will create two riser line conditions – one in
the liquid line in one mode and one in the vapor line in the oppo-
site mode. See the following table to identify which lines are risers
in this installation.
LIQUID LINE RISER
Refer to Piping Recommendations, Table 4; observe Max Lift lim-
its for liquid line according to unit mode, equivalent line length
and pipe size.
VA P O R L I N E R I S E R
Refer to Table 5for maximum pipe size in single pipe vapor risers.
All pipe size recommendations in Piping Recommendations,
Table 4, satisfy these maximum vapor line sizes. If this installation
is re-using existing piping, check the vapor line sizes against these
maximum values; replace riser sections with these pipe sizes if
necessary.
Install Filter Drier and Moisture Indicator
Every unit MUST have a bi-directional filter drier in the liquid
line. Locate the filter drier(s) at the indoor unit, close to the indoor
coil’s thermostatic expansion valve (TXV) inlets. The 38AUQ
units include one Puron-duty filter drier, shipped in cartons at-
tached to the unit basepan. Remove the filter drier and prepare to
install in the liquid line at the indoor coil. Do not remove connec-
tion fitting plugs until ready to connect and braze the filter drier
into the liquid line position. See Table 6.
Installation of liquid line moisture indicating sight glass in each
circuit is recommended. Locate the sight glass(es) between the
outlet of the filter drier and the TXV inlet.
Refer to Table 7for recommendations on refrigeration specialties.
Select the filter drier for maximum unit capacity and minimum
pressure drop. Complete the refrigerant piping from the indoor
unit to the outdoor unit before opening the liquid and vapor ser-
vice valves at the outdoor unit.
MODE
38AUQ UNIT
BELOW ID UNIT
38AUQ UNIT
ABOVE ID UNIT
Riser in Riser in
Cooling Liquid Vapor
(Suction Gas)
Heating Vapor
(Discharge Gas) Liquid
Table 5 — Maximum Vapor Line Sizes
38AUQ UNIT
38AUQ UNIT
BELOW ID UNIT
38AUQ UNIT
ABOVE ID UNIT
Max Diameter, Single Pipe (in.)
(D/E)07 1-1/8 1-1/8
(M/N)08 1-3/8 1-5/8
(D/E)12 1-3/8 1-3/8
IMPORTANT: A refrigerant receiver is not provided with
the unit. Do not install a receiver.
Table 6 — Puron-Duty Filter Drier(s)
UNIT QTY LIQUID
LINE OD
DESSICANT
VOLUME
PART NO.
REF.
38AUQ*07 1 3/8 in. 8 cu. in. KH43LS088
38AUQ*08 1 1/2 in. 16 cu. in. KH43LS102
38AUQ*12 1 1/2 in. 16 cu. in. KH43LS102
Table 7 — Refrigerant Specialties Part Numbers
LIQUID LINE SIZE (in.) LIQUID LINE SOLENOID VALVE (LLSV) SOLENOID COIL SIGHT GLASS FILTER DRIER
3/8 EF680033 plus EF680039 biflow kit EF680037 KM680008 Provided with unit See
Table 6
1/2 EF680035 plus EF680039 biflow kit EF680037 KM680004
5/8 EF680036 plus EF680039 biflow kit EF680037 KM680005

10
Install Liquid Line Solenoid Valves
It is recommended that a bi-directional solenoid valve be placed in
the main liquid line (see Fig. 5and 6) between the outdoor unit
and the indoor coil. Locate the solenoid valve at the end of the
liquid line, near the outdoor unit connections, with flow direction
arrow pointed at the outdoor unit. Refer to Table 7. (A liquid line
solenoid valve is required when the liquid line length exceeds 75 ft
[23 m].) This valve prevents refrigerant migration (which causes
oil dilution) to the compressor during the off cycle, at low outdoor
ambient temperatures. Wire the solenoid according to the unit
label diagram.
Fig. 5 — Location of Sight Glass(es) and Filter Driers
(typical 38AUQ size 07 and 08)
Fig. 6 — Location of Sight Glass(es) and Filter Driers
(typical 38AUQ size 12)
Make Piping Connections
Piping connections at the 38AUQ unit are ball valves with stub
tube extensions. Do not open the unit service valves until all inter-
connecting tube brazing as been completed.
The stub tube connections include 1/4 in. SAE service fittings
with Schrader valve cores (see Fig. 7). Before making any brazed
connections to the unit service valves, remove both Schrader valve
caps and cores and save for re-installation. Connect a source for
nitrogen to one of these service fittings during tube brazing to pre-
vent the formation of copper oxides inside the tubes at brazed
joints.
Fig. 7 — Typical Piping Connection Assembly
When connecting the field tubing to the 38AUQ service valves,
wrap the valves in wet rags to prevent overheating
Pressure-test all joints from outdoor unit connections over to the
indoor coil, using nitrogen as pressure and with soap-and-bubbles.
When pressure-testing is completed, remove the nitrogen source at
the outdoor unit service valves and re-install the two Schrader
valve cores. Torque the cores to 2-3 in.-lb (23-34 N-cm).
Where vapor line is exposed to outdoor air, line must be insulated.
See Table 8for insulation requirements.
Evacuation/Dehydration
Evacuate and dehydrate the connected refrigeration system(s) (ex-
cluding the 38AUQ unit) to 500 microns using a two-stage vacu-
um pump attached to the service ports outside the 38AUQ service
valves, following description in GTAC II, Module 4, System
Dehydration.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Failure to use a solenoid valve relay (SVR) P/N HN61PC005
may cause overload of Comfort Alert Diagnostic Module
(CADM) and compressor alarm lock out.
LEGEND
TXV — Thermostatic Expansion Valve
15 Diams
Min 10
Diams 8 Diams
Min
Indoor
Coil CKT
Airflow
TXV
Sensing
Bulb
Equalizer Line
Sight Glass
A Location
TXV
Filter Drier
A Location
LEGEND
TXV — Thermostatic Expansion Valve
INDOOR
COIL CKT 2
AIRFLOW
INDOOR
COIL CKT 1
AIRFLOW
15 DIAMS
MIN 10
DIAMS
8 DIAMS
MIN
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT GLASS
LOCATION
TXV
CKT 2
FILTER DRIE
R
LOCATION
TXV
SENSING
BULB
TXV
CKT 1
8 DIAMS
MIN
15 DIAMS
MIN 10
DIAMS
Table 8 — Insulation for Vapor Line Exposed to
Outdoor Conditions
LENGTH OF
EXPOSED VAPOR LINEa
NOTE(S):
a. Recommended vapor line insulation for piping exposed to outdoor conditions
to prevent loss of heating during heating cycle. When vapor line goes through
interior spaces, insulation should be selected to prevent condensation on cool-
ing cycle. Heating capacity should be reduced 1000 Btuh (295 W) if over 35 ft
(11 m) of vapor line with 3/4 in. (19 mm) insulation is exposed to outdoor con-
ditions.
INSULATION THICKNESSb
b. Closed cell foam insulation with a thermal conductivity of: 0.28 Btu • in./ft2• h •
°F (0.04 W/m • °C).
ft m in. mm
10 3 3/8 10
25 8 1/2 13
35 11 3/4 19
50 15 3/4 19
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron®(R-410A) refrigerant systems operate at higher pres-
sures than standard R-22 systems. Do not use R-22 service
equipment or components on Puron refrigerant equipment.
IMPORTANT: Charge in Cooling mode only!
Factory
High-Flow
Access Port
Service Valve
with Stem Cap
Field Service
Access Port
(Schrader Core)
Sweat
Connection

11
Preliminary Charge
Before starting the unit, charge R-410A liquid refrigerant into the
high side of each 38AUQ circuit through the liquid service
valve(s). The amount of refrigerant added must be at least 80% of
the operating charge listed in Table 4for LINEAR line length
LESS the factory charge quantity (if factory shipping charge has
not been removed). See the following example.
Allow high and low side pressures to equalize. If pressures do not
equalize readily, charge R-410A vapor (using special service man-
ifold with expansion device) into the vapor line service port for the
low side of system to assure charge in the evaporator. Refer to
GTAC II, Module 5, Charging, Recover, Recycling, and Reclama-
tion for liquid charging procedures.
Example:
38AUQ*08
60 ft (18.3 m) linear line length
Equivalent line length 90 ft (27.4 m)
Liquid Lift: 20 ft (6.1 m)
Select line sizes from Table 4:
Liquid 1/2 in.
Vapor 1-1/8 in.
Charge 23.0 lb (at 75 ft linear length)
80% of Operating Charge:
0.80 x 23.0 = 17.6 lb
Factory Shipping Charge: 9 lb
Field-charge quantity: 17.6 lb – 9.0 lb = 8.6 lb
For linear line lengths longer than 100 ft (30.5 m), contact
your local Carrier representative for system charge value.
Step 6 — Install Accessories
Accessories requiring modifications to unit wiring should be com-
pleted now. These accessories may include Winter Start controls,
Low Ambient controls, phase monitor, Compressor Lockout. Re-
fer to the instructions shipped with the accessory. Additionally, for
low ambient controls, refer to Table 9.
Step 7 — Complete Electrical Connections
NOTE: Field-supplied wiring shall conform with the limitations
of minimum 63°F (33°C) rise.
FIELD POWER SUPPLY
If equipped with optional Powered Convenience Outlet: The pow-
er source leads to the convenience outlet’s transformer primary are
not factory connected. Installer must connect these leads accord-
ing to required operation of the convenience outlet. If an always-
energized convenience outlet operation is desired, connect the
source leads to the line side of the unit-mounted disconnect.
(Check with local codes to ensure this method is acceptable in
your area.) If a de-energize via unit disconnect switch operation of
the convenience outlet is desired, connect the source leads to the
load side of the unit disconnect. On a unit without a unit-mounted
disconnect, connect the source leads to compressor contactor C
with unit field power leads.
Field power wires are connected to the unit at line-side pressure
lugs on compressor contactor C and TB1 (see wiring diagram la-
bel for control box component arrangement) or at factory-installed
option non-fused disconnect switch. Max wire size is no. 4 AWG
(copper only).
NOTE: TEST LEADS — Unit may be equipped with short leads
(pigtails) on the field line connection points on contactor C or op-
tional disconnect switch. These leads are for factory run-test pur-
poses only; remove and discard before connecting field power
wires to unit connection points. Make field power connections di-
rectly to line connection pressure lugs only.
Fig. 8 — Disconnect Switch and Unit
Table 9 — Minimum Outdoor Air Operating
Temperature
UNIT
PERCENT
COMPRESSOR
CAPACITY
MINIMUM OUTDOOR
TEMP, °F (°C)a
NOTE(S):
a. Applies to Cooling mode of operation only.
Standard Unit Head Pressure
Controlb
b. Wind baffles (field-supplied and field-installed) are recommended for all units
with low ambient head pressure control. Refer to Low Ambient Control Instal-
lation Instructions (shipped with accessory) for details.
38AUQ 07 100 35 (1.7) –20 (–28.9)
38AUQ 08 100 35 (1.7) –20 (–28.9)
38AUQ 12 100 35 (1.7) –20 (–28.9)
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or
death.
Do not use gas piping as an electrical ground. Unit cabinet
must have an uninterrupted, unbroken electrical ground to
minimize the possibility of personal injury if an electrical fault
should occur. This ground may consist of electrical wire con-
nected to unit ground lug in control compartment, or conduit
approved for electrical ground when installed in accordance
with NEC (National Electrical Code); ANSI/NFPA 70, latest
edition (in Canada, Canadian Electrical Code CSA [Canadian
Standards Association] C22.1), and local electrical codes.
WARNING
FIRE HAZARD
Failure to follow this warning could result in intermittent
operation or performance satisfaction.
Do not connect aluminum wire between disconnect switch and
condensing unit. Use only copper wire. (See Fig. 8.)
Copper
Wire Only
Electric
Disconnect
Switch
Aluminum
Wire

12
UNITS WITHOUT FACTORY-INSTALLED DISCONNECT
When installing units, provide a disconnect switch per NEC (Na-
tional Electrical Code) of adequate size. Disconnect sizing data is
provided on the unit informative plate. Locate on unit cabinet or
within sight of the unit per national or local codes. Do not cover
unit informative plate if mounting the disconnect on the unit
cabinet.
UNITS WITH FACTORY-INSTALLED DISCONNECT
The factory-installed option disconnect switch is located in a
weatherproof enclosure located under the main control box. The
manual switch handle is accessible through an opening in the ac-
cess panel.
ALL UNITS
All field wiring must comply with NEC and all local codes. Size
wire based on MCA (Minimum Circuit Amps) on the unit infor-
mative plate. See Fig. 9for power wiring connections to the unit
power terminal block and equipment ground. Maximum wire size
is no. 4 ga AWG per pole.
Provide a ground-fault and short-circuit over-current protection
device (fuse or breaker) per NEC Article 440 (or local codes). Re-
fer to unit informative data plate for MOCP (Maximum Overcur-
rent Protection) device size.
Fig. 9 — Power Wiring Connections
All units except 208/230-v units are factory wired for the voltage
shown on the nameplate. If the 208/230-v unit is to be connected
to a 208-v power supply, the control transformer must be rewired
by moving the black wire with the 1/4 in. female spade connector
from the 230-v connection and moving it to the 208-v 1/4 in. male
terminal on the primary side of the transformer. Refer to unit label
diagram for additional information.
All field wiring must comply with the NEC and local
requirements.
VOLTAGE AND CURRENT BALANCE
Voltage to compressor terminals during operation must be within
voltage range indicated on unit nameplate. See Table 10. On
3-phase units, voltages between phases must be balanced within
2% and the current within 10%. Use the formula shown below
Table 10, Note d(see page 15) to determine the percent of voltage
imbalance. Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to electrical
components. Such operation would invalidate any applicable
Carrier warranty.
Convenience Outlets
Two types of convenience outlets are offered on 38AUQ models:
non-powered and unit-powered. Both types provide a 125-volt
GFCI (ground-fault circuit-interrupter) duplex receptacle rated at
15-A behind a hinged waterproof access cover, located on the end
panel of the unit. See Fig. 10.
Fig. 10 — Convenience Outlet Location
Non-powered type: This type requires the field installation of a
general-purpose 125-volt 15-A circuit powered from a source
elsewhere in the building. Observe national and local codes when
selecting wire size, fuse or breaker requirements and disconnect
switch size and location. Route 125-v power supply conductors
into the bottom of the utility box containing the duplex receptacle.
Unit-powered type: A unit-mounted transformer is factory-
installed to stepdown the main power supply voltage to the unit to
115-v at the duplex receptacle. This option also includes a manual
switch with fuse, located in a utility box and mounted on a bracket
behind the convenience outlet; access is through the unit’s control
box access panel. See Fig. 10.
The primary leads to the convenience outlet transformer are not
factory-connected. Selection of primary power source is a
customer-option. If local codes permit, the transformer primary
leads can be connected at the line-side terminals on the unit-
mounted non-fused disconnect or HACR breaker switch; this will
provide service power to the unit when the unit disconnect switch
or HACR switch is open. Other connection methods will result in
the convenience outlet circuit being de-energized when the unit
disconnect or HACR switch is open. See Fig. 11.
Duty Cycle: The unit-powered convenience outlet has a duty cycle
limitation. The transformer is intended to provide power on an in-
termittent basis for service tools, lamps, etc; it is not intended to
provide 15-amps loading for continuous duty loads (such as
11 13
L1 L2 L3
C TB1
208/230-3-60
460-3-60
575-3-60
Units Without Disconnect Option
Units With Disconnect Option
2
4
6
1
3
5
L1
L2
L3
Optional
Disconnect
Switch
Disconnect factory test leads; discard.
Factory
Wiring
Disconnect
per
NEC
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Units with convenience outlet circuits may use multiple dis-
connects. Check convenience outlet for power status before
opining unit for service. Locate its disconnect switch, if appro-
priate, and open it. Tag-out this switch, if necessary.
Control Box
Access Panel
Pwd-CO
Transformer
Convenience
Outlet
GFCI
Pwd-CO
Fuse
Switch

13
electric heaters for overnight use). Observe a 50% limit on circuit
loading above 8-amps (i.e., limit loads exceeding 8-amps to
30 minutes of operation every hour).
Fig. 11 — Powered Convenience Outlet Wiring
Test the GFCI receptacle by pressing the TEST button on the face
of the receptacle to trip and open the receptacle. Check for proper
grounding wires and power line phasing if the GFCI receptacle
does not trip as required. Press the RESET button to clear the
tripped condition.
Fuse on power type: The factory fuse is a Bussman™1
“Fusetron™”1T-15, non-renewable screw-in (Edison base)
type plug fuse.
Using unit-mounted convenience outlets: Units with unit-mounted
convenience outlet circuits will often require that two disconnects
be opened to de-energize all power to the unit. Treat all units as
electrically energized until the convenience outlet power is also
checked and de-energization is confirmed. Observe National Elec-
trical Code Article 210, Branch Circuits, for use of convenience
outlets.
Installing Weatherproof Cover
A weatherproof while-in-use cover for the factory installed conve-
nience outlets is now required by UL standards. This cover cannot
be factory mounted due its depth; it must be installed at unit instal-
lation. For shipment, the convenience outlet is covered with a
blank cover plate.
The weatherproof cover kit is shipped in the unit’s control box.
The kit includes the hinged cover, a backing plate and gasket.
DISCONNECT ALL POWER TO UNIT AND
CONVENIENCE OUTLET
Remove the blank cover plate at the convenience outlet; discard
the blank cover.
Loosen the two screws at the GFCI duplex outlet, until approxi-
mately 1/2 in. (13 mm) under screw heads are exposed. Press the
gasket over the screw heads. Slip the backing plate over the screw
heads at the keyhole slots and align with the gasket; tighten the
two screws until snug (do not overtighten).
Mount the weatherproof cover to the backing plate as shown in
Fig. 12. Remove two slot fillers in the bottom of the cover to per-
mit service tool cords to exit the cover. Check for full closing and
latching.
Fig. 12 — Weatherproof Cover Installation
NOTE: Check all factory and field electrical connections for
tightness.
FIELD CONTROL WIRING
38AUQ unit control voltage is 24 v. See Fig. A-G in Appendix B
for typical field control connections and the unit’s label diagram
for field-supplied wiring details. Route control wires to the
38AUQ unit through the opening in unit’s end panel to the con-
nections terminal board in the unit’s control box.
Remainder of the system controls connection will vary according
to the specific construction details of the indoor section. Figure 13
depicts typical connections to a Carrier 40RFQ fan coil unit. Plan
for field connections carefully and install control wiring correctly
per the project plan. Additional components and supplemental
transformer accessory may be required.
The 38AUQ unit requires an external temperature control device.
This device can be a field-supplied thermostat (field-supplied) or a
thermostatic emulation device provided as part of a third-party
Building Management System.
THERMOSTAT
Install a Carrier-approved accessory thermostat according to in-
stallation instructions included with the accessory. For complete
economizer function, select a two-stage cooling thermostat.
38AUQ(D/E/M/N) units require a two-stage thermostat.
38AUQ unit control system requires a conventional electric ther-
mostat that will energize the G terminal on a call for Cool and
Heat mode. Do not configure the thermostat a heat pump type;
Heat mode will not work with a thermostat configured for heat
pump.
Locate the thermostat accessory on a solid wall in the conditioned
space to sense average temperature in accordance with the ther-
mostat installation instructions.
If the thermostat contains a logic circuit requiring 24-v power, use
a thermostat cable or equivalent single leads of different colors
with minimum of five leads between the 38AUQ unit’s outdoor
unit connection board and the indoor unit connection board. If the
thermostat does not require a 24-v source (no “C” connection re-
quired), use a thermostat cable or equivalent with minimum of
four leads. One additional lead is required between the indoor unit
connection board and the thermostat for terminal G. If the
1. Third-party trademarks and logos are the property of their respective
owners.
PRIMARY
CONNECTIONS
UNIT
VOLTAGE
208, 230
460
575
CONNECT
AS
240
480
600
L1: RED + YEL
L2: BLU + GRA
L1: RED
Splice BLU + YEL
L2: GRA
L1: RED
L2: GRA
TRANSFORMER
TERMINALS
H1 + H3
H2 + H4
H1
H2 + H3
H4
H1
H2
Cover — While-In-Use
Weatherproof
Baseplate For
GFCI Receptacle
Gasket
GFCI Receptacle
Not Included
TOP
TOP
TOP
WET LOCA
TIONS
WETLOCATIONS

14
accessory electric heat is used, one additional wire is required be-
tween the indoor unit connection board and the thermostat for ter-
minal W2. Check the thermostat installation instructions for addi-
tional features which might require additional conductors in the
cable.
NOTE: Two-stage units require an additional wire for the Y2
connection.
For wire runs up to 50 ft (15 m), use no. 18 AWG (American Wire
Gauge) insulated wire (35°C minimum). For 50 to 75 ft (15 to
23 m), use no. 16 AWG insulated wire (35°C minimum). For over
75 ft (23 m), use no. 14 AWG insulated wire (35°C minimum).
All wire sizes larger than no. 18 AWG cannot be directly connect-
ed to the thermostat and will require a junction box and splice at
the thermostat.
Fig. 13 — Typical Remote Thermostat Connections
EXTERNAL CONTROL DEVICES
The 38AUQ control transformers provide 24-v NEC Class 2 pow-
er sources to energize external control devices. These devices will
include the indoor fan motor contactor (or control relay or unit
control board in the fan coil unit). These devices may also include
a liquid line solenoid valve, economizer control relay, supplemen-
tal electric heater contactors or control relays and other devices
selected by system designer.
Control transformer TRAN1 provides control power through ter-
minal R to C on the 38AUQ’s outdoor unit field connection termi-
nal strip for supply fan motor interlock. This source may also be
used to energize economizer control relay and electric heater
contactors or relays. Maximum available power is 50 va. Check
concurrent loadings by external control devices. If the maximum
concurrent loading exceeds 50 va, purchase and install the acces-
sory Transformer-Relay package (available for 208/230 and 460-v
units).
Control transformer TRAN2 provides control power through ter-
minal A1 (9) to C for the liquid line solenoid. Maximum available
power is 15 va. This output is switched ON/OFF by the Solenoid
Valve Relay (field-supplied, use Carrier Service Part
P/N HN61PC005).
THERMOSTAT
R
G
Y1
O/B/Y2
W1
W2
C
REFER
TO FAN
COIL
LABEL
IN
CONTROL
BOX
OUTDOOR UNIT
CONNECTION
BOARD (TB)
R
Y1
Y2
W1
W2
G
C
X
A1
A2
1
2
3
4
5
6
7
8
9
10
HEAT PUMP INDOOR UNIT
ELECTRIC HEATER
TB2
W1
W2
C
H1
H2
HEAT PUMP INDOOR UNIT
WITH ELECTRIC HEATER
LLSV

15
Example: Supply voltage is 230-3-60
Determine maximum deviation from average voltage.
(AB) 227-224 = 3 v
(BC) 231-227 = 4 v
(AC) 227-226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
Table 10 — Electrical Data — 38AUQ*07-12 60 Hz Unitsa,b
NOTE(S):
a. In compliance with NEC requirements for multimotor and combination load equipment (refer to NEC Articles 430 and 440), the overcurrent protective device for the unit
shall be fuse or HACR breaker. Canadian units may be fuse or circuit breaker.
b. Motor RLA and LRA values are established in accordance with Underwriters’ Laboratories (UL). Standard 1995.
UNIT
NOMINAL
POWER
SUPPLYc,d
c. The 575-v units are UL, Canada-listed only.
d. Unbalanced 3-Phase Supply Voltage: Never operate a motor where a phase imbalance in supply voltage is greater than 2%. Use the formula below to determine the
percentage of voltage imbalance.
VOLTAGE
RANGE
COMPRESSOR WITHOUT POWERED CONVENIENCE OUTLET
No. 1 No. 2 OFM (ea) Power Supply Disconnect Size
V-Ph-Hz Min Max RLA LRA RLA LRA Qty FLA MCAe
e. The MCA values are calculated in accordance with The NEC. Article 440.
Fuse or
HACR
Brkr
FLA LRA
38AUQD/E07
208/230-3-60 187 253 17.5 136 — — 2 1.5 25/25 30/30 24/24 142/142
460-3-60 414 506 8.4 66 — — 2 0.8 13 20 12 70
575-3-60 518 633 6.3 55 — — 2 0.7 10 15 9 59
38AUQM/N08
208/230-3-60 187 253 27.4 164 — — 2 1.5 38/38 60/60 35/35 170/170
460-3-60 414 506 12.9 94 — — 2 0.8 18 30 17 98
575-3-60 518 633 10.0 65 — — 2 0.7 14 20 13 69
38AUQD/E12
208/230-3-60 187 253 15.9 110 15.6 110 2 1.5 39/39 50/50 40/40 226/226
460-3-60 414 506 7.7 52 7.7 52 2 0.8 19 25 20 108
575-3-60 518 633 5.7 39 5.8 39 2 0.7 15 20 15 82
UNIT
NOMINAL
POWER
SUPPLYc,d
VOLTAGE
RANGE
COMPRESSOR WITH POWERED CONVENIENCE OUTLET
No. 1 No. 2 OFM (ea) Power Supply Disconnect Size
V-Ph-Hz Min Max RLA LRA RLA LRA Qty FLA MCAe
Fuse or
HACR
Brkr
FLA LRA
38AUQD/E07
208/230-3-60 187 253 17.5 136 — — 2 1.5 30/30 45/45 29/29 147/147
460-3-60 414 506 8.4 66 — — 2 0.8 15 20 14 72
575-3-60 518 633 6.3 55 — — 2 0.7 11 15 11 61
38AUQM/N08
208/230-3-60 187 253 27.4 164 — — 2 1.5 43/43 60/60 40/40 175/175
460-3-60 414 506 12.9 94 — — 2 0.8 20 30 19 100
575-3-60 518 633 10.0 65 — — 2 0.7 16 25 15 71
38AUQD/E12
208/230-3-60 187 253 15.9 110 15.6 110 2 1.5 44/44 50/50 45/45 231/231
460-3-60 414 506 7.7 52 7.7 52 2 0.8 22 25 22 110
575-3-60 518 633 5.7 39 5.8 39 2 0.7 17 20 17 84
% Voltage
Imbalance = 100 x max voltage deviation from average voltage
average voltage
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =(224 + 231 + 226) =681 =227
3 3
% Voltage Imbalance =100x 4=1.78%
227
IMPORTANT: If the supply voltage phase imbalance is more than 2%,
contact your local electric utility company immediately.
ABC
MOTOR
LEGEND
BRKR — Circuit Breaker
FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps Protection
NEC — National Electrical Code
PWRD CO — Powered Convenience Outlet
RLA — Rated Load Amps
UNPWR CO — Unpowered Convenience Outlet

16
Step 8 — Wind Baffles for Low Ambient Control
38AUQN and 38AUQE units includes the factory installed low
ambient controller.
Units with low ambient control require the addition of wind baf-
fles to ensure full range low ambient operation. Material data and
dimensions for wind baffles are included in the Appendix C sec-
tion, Low Ambient Control, starting on page 44. Fabricate the
wind baffles and mount per instructions.
PRE-START-UP
System Check
1. Check all indoor section and other equipment auxiliary com-
ponents. Consult the manufacturer’s instructions regarding
any other equipment connected to the condensing unit. If the
unit has field-installed accessories, be sure all are properly
installed and correctly wired. If used, the airflow switch must
be properly installed.
2. Be sure the unit is properly leak checked and dehydrated.
3. Check tightness of all electrical connections.
4. Open the liquid line and suction line service valves.
5. Be sure the unit is properly charged. See “Preliminary
Charge”, below.
6. The electrical power source must agree with the unit’s name-
plate rating.
7. The crankcase heater must be firmly attached to the compres-
sor crankcase. Be sure the crankcase is warm (heater must be
on for 24 hours before starting compressor).
Turn On Crankcase Heater
Turn on the crankcase heater for 24 hours before starting the unit
to be sure all the refrigerant is out of the oil. To energize the crank-
case heater, proceed as follows:
1. Set the space thermostat set point above the space tempera-
ture so there is no demand for cooling.
2. Close the field disconnect.
Preliminary Charge
Before starting the unit, charge liquid refrigerant into the high side
of the system through the liquid service valve. The amount of re-
frigerant added must be at least 80% of the operating charge listed
in the Physical Data table (Tables 2and 3on page 5). Allow high
and low side pressures to equalize before starting compressor. If
pressures do not equalize readily, charge vapor on low side of sys-
tem to assure charge in the evaporator. Refer to GTAC II,
Module 5, Charging, Recover, Recycling, and Reclamation for
liquid charging procedures.
START-UP
38AUQ Units
The compressor crankcase heater must be on for 24 hours before
start-up. After the heater has been on for 24 hours, the unit can be
started. If no time elapsed since the preliminary charge step was
completed, it is unnecessary to wait the 24-hour period.
PRELIMINARY CHECKS
1. Check that electric power supply agrees with unit nameplate
data.
2. Verify that the compressor crankcase heater is securely in
place.
3. Check that the compressor crankcase heater has been on at
least 24 hours.
4. Recheck for leaks using the procedure outlined in the Pre-
Start-Up section, Leak Test and Dehydration. If any leaks are
detected, repair as required. Evacuate and dehydrate as
described in the Leak Test and Dehydration section.
5. Ensure that the preliminary charge has been added as
described in the Pre-Start-Up section, Preliminary Charge.
6. All internal wiring connections must be tight, and all barriers
and covers must be in place.
NOTE: The units are factory charged with the required amount of
oil. If recharging in required, use Emkarate®1 RL 32-3MAF.
COMPRESSOR ROTATION
On 3-phase units with scroll compressors, it is important to be cer-
tain that the compressor is rotating in the proper direction. The
38AUQ units are equipped with a Comfort Alert Diagnostic Mod-
ule (CADM). Alert Code 7 indicates reverse power phasing.
To correct phase order:
1. Turn off power to the unit, tag disconnect.
2. Reverse any two of the unit power leads.
3. Reapply power to the compressor, verify correct pressures.
To verify the compressor is rotating in the proper direction:
1. Connect service gauges to the suction and liquid pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the liquid pressure
should rise, as is normal on any start-up.
COMPRESSOR OVERLOAD
This overload interrupts power to the compressor when either the
current or internal motor winding temperature becomes excessive,
and automatically resets when the internal temperature drops to a
safe level. This overload may require up to 60 minutes (or longer)
to reset. If the internal overload is suspected of being open, discon-
nect the electrical power to the unit and check the circuit through
the overload with an ohmmeter or continuity tester.
IMPORTANT: Before beginning Pre-Start-Up or Start-Up,
review Start-Up Checklist at the back of this book. The
Checklist assures proper start-up of a unit and provides a
record of unit condition, application requirements, system
information, and operation at initial start-up.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Do not attempt to start the heat pump system, even
momentarily, until the following steps have been completed.
Compressor damage may result.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Prior to starting compressor, a preliminary charge of refrigerant
must be added to avoid possible compressor damage.
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17
ADVANCED SCROLL TEMPERATURE PROTECTION
(ASTP)
A label located above the terminal box identifies Copeland™1
Scroll compressor models that contain this technology. See
Fig. 14. Advanced Scroll Temperature Protection (ASTP) is a
form of internal discharge temperature protection, that unloads the
scroll compressor when the internal temperature reaches approxi-
mately 300°F. At this temperature, an internal bi-metal disk valve
opens and causes the scroll elements to separate, which stops com-
pression. Suction and discharge pressures balance while the motor
continues to run. The longer the compressor runs unloaded, the
longer it must cool before the bi-metal disk resets. See Fig. 15.
Fig. 14 — Advanced Scroll Temperature Protection
Label
Fig. 15 — Recommended Minimum Cool-Down Time
After Compressor is Stopped
To manually reset ASTP, the compressor should be stopped and
allowed to cool. If the compressor is not stopped, the motor will
run until the motor protector trips, which occurs up to 90 minutes
later. Advanced Scroll Temperature Protection will reset automati-
cally before the motor protector resets, which may take up to
2hours.
START UNIT
Disconnect the field low voltage lead at the 38AUQ unit’s R ter-
minal to prevent compressor operation. Close the 38AUQ discon-
nect switch. Only the crankcase heater will be energized.
Reconnect the field low voltage lead to the 38AUQ unit’s R termi-
nal. Adjust thermostat setting for Cool below space temperature.
ADJUST REFRIGERANT CHARGE
The unit must be charged in Cooling mode only. Refer to Cooling
Charging Charts, Fig. 16-18. For applications with line lengths
greater than 100 ft, contact Carrier representative. Vary refrigerant
until the conditions of the chart are met. The charts are based on
charging the units to the correct subcooling 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 service valve. Mount the temperature sensing de-
vice on the liquid line close to the liquid line service valve, and in-
sulate it so that outdoor ambient temperature does not affect the
reading. Indoor airflow must be within the unit’s normal operating
range. Operate the unit for a minimum of 15 minutes. Ensure that
pressure and temperature readings have stabilized. Plot the liquid
pressure and temperature on chart and add or reduce the charge to
meet the curve. Adjust the charge to conform with the charging
chart, using the liquid pressure and temperature to read the chart.
FINAL CHECKS
Ensure that all safety controls are operating, control panel covers
are on, and the service panels are in place
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owners.
0
10
20
30
40
50
60
70
80
90
100
110
120
0 102030 40 607080 9050
Compressor Unloaded Run Time (Minutes)*
NOTES:
1 . Various factors, including high humidity, high ambient temperature,
and the presence of a sound blanket will increase cool-down times.
*Times are approximate.
Recommended Cooling Time*
(Minutes)
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Never charger liquid into the low-pressure side of the system.
Do not overcharge. During charging or removal of refrigerant,
be sure indoor-fan system is operating. Ensure both outdoor
fan motors are running; bypass any low ambient function.

18
Fig. 16 — 38AUQD/E07 Charging Chart
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
Tem perature at Liquid Valve (°C / °F)
Pre ssure at Liquid V alve (PSIG / Kpa)
6 TON HEAT PUMP DUAL STAGE CHARGING CHART PURON
(COMPRESSOR FULL LOAD, ALL CONDENSER FANS OPERATING)
Add Charge if
Above the Curve
Rem ove Charge if
Be lo w the Cu r ve
PN: 38AU000485 REV -

19
Fig. 17 — 38AUQ*08 Charging Chart
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
Tem perature at Liquid Valve (°C / °F)
Pre ssure at Liquid V alve (PSIG / Kpa)
7.5 Ton Dual Stage Heat Pump Charging Chart R410a
Refrigerant
Add Charge if
Above the Curve
Re m ove Char ge if
Be lo w the Cu r ve
A
38AU000063

20
Fig. 18 — 38AUQD/E12 Charging Chart
OPERATING SEQUENCE
Base Unit Controls
INDOOR (SUPPLY) FAN
If the thermostat fan operation is selected as Continuous, then the
indoor (supply) fan motor, which is remotely located in the fan
coil, runs continuously. If the thermostat fan operation is selected
as Automatic, then the indoor (supply) fan motor runs when there
is a call for Cooling or Heating. When thermostat is satisfied, then
the indoor (supply) fan motor stops. If there is a fan fault or a shut-
down condition in the fan coil, then the indoor (supply) fan will
not run if there is a call for ventilation, cooling, or heating and the
38AU unit will act as if it is not receiving a cooling or heating
demand.
COOLING, UNIT WITHOUT ECONOMIZER —
TWO-STAGE UNITS
For two stage units, the 38AUQ(D/E)07 uses a two-stage
Copeland™1 Ultratech Scroll compressor in conjunction with a
two-stage Comfort Alert Module (CADM). The 38AUQ(D/E)12
uses two compressors in tandem on a single circuit in conjunction
with two single-stage Comfort Alert Modules (CADM).
38AUQ(D/E)07 and 38AUQ(M/N)08
When thermostat calls for Stage 1 Cooling, terminal Y1 is ener-
gized. The 38AUQ unit’s Defrost Board (DFB) receives this input
at P2-5. DFB issues 24-v outputs at OF, P3-7 (RVS1) and P3-10
(COMP1). The OF output energizes outdoor fan relay (OFR);
both outdoor fan motors start and run. The output RVS1 energizes
the reversing valve solenoid (RVS); Reversing valve switches to
Cooling position. Output PL3-10 (COMP1, 24-v) is received at
CADM terminal Y. If anti-recycle time delay period has not ex-
pired, safety pressure switches are open, and/or lockout alarms are
active, CADM relay will remain open, preventing compressor
start. When safety pressure switches are closed and CADM time
delay expires, the CADM relay closes, energizing Solenoid Valve
Relay SVR and compressor contactor C. SVR contacts close, en-
ergizing the external liquid line solenoid valve. Solenoid valve
LLSV opens. Compressor contactor C closes, energizing the com-
pressor motor. Compressor starts and system runs in Stage 1 Cool-
ing mode.
When thermostat calls for Stage 2 Cooling, terminal Y2 is ener-
gized. The 38AUQ unit’s Defrost Board (DFB) receives this input
at P2-4. DFB issues 24-v outputs at OF, P3-8 (COMP2). Output
PN: 38AU000486 REV -
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