Carrier 38AUD Dimensions and installation guide

1
38AUD
Air Cooled Condensing Units
50 Hz
With PuronR(R---410A) Refrigerant
S i z e s 0 7 --- 1 4
Installation, Start---Up
and Service Instructions
CONTENTS
SAFETY CONSIDERATIONS 2....................
INSTALLATION GUIDELINES 2..................
Replacement/Retrofit — R--22 to Puron 2...........
INSTALLATION 10 - 21.........................
Jobsite Survey 10...............................
Step 1 -- Plan for Unit Location 10.................
Step 2 -- Complete Pre--Installation Checks 10........
Step 3 -- Prepare Unit Mounting Support 10..........
Step 4 -- Rig and Mount the Unit 10................
Step 5 -- Complete Refrigerant Piping Connections 11...
Step 6 -- Install Accessories 18....................
Step 7 -- Complete Electrical Connections 18.........
PRE-START-UP 22...............................
System Check 22...............................
Turn On Crankcase Heater 22.....................
Preliminary Charge 22...........................
START--UP 22 - 30..............................
Preliminary Checks 22...........................
Start Unit 23...................................
OPERATING SEQUENCE 31......................
Indoor (Supply) Fan 31..........................
Cooling, Unit Without Economizer 31..............
Cooling, Unit With Economizer 31.................
Heating 31....................................
ROUTINE SYSTEM MAINTENANCE 32............
Quarterly Inspection (and 30 days after initial start) 32...
Seasonal Maintenance 32........................
SERVICE 32 - 41................................
Refrigeration System 32.........................
Compressor Oil 32..............................
Servicing Systems on Roofs with
Synthetic Materials 32...........................
Liquid Line Filter Drier 33.......................
Filed Refrigerant Access Ports 33..................
Factory High--Flow Access Ports 33................
Comfort Alert Diagnostic Module 34...............
Compressor Protection 36........................
Crankcase Heater 36............................
Low--Pressure Switch 36.........................
High--Pressure Switch 36.........................
Outdoor Fans 36................................
Lubrication 36.................................
Coil Type Identification 39.......................
N O VAT I O N tCoil Cleaning and Maintenance 39.....
Repairing NOVATION Condenser Tube Leaks 39.....
Replacing NOVATION Condenser Coil 39...........
Routine Cleaning of Round-Tube Plate Fin
(RTPF) Coils 40................................
Fastener Torque Values 41........................
TROUBLESHOOTING 41 -- 42.....................
APPENDIX A
Air Conditioner & Heat Pump with PuronR—
Quick Reference Guide 43.........................
APPENDIX B
Wiring Diagram List 43...........................
APPENDIX C
Low Ambient Option — Factory Installed 44..........
START--UP CHECKLIST 49 -- 50...................

2
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, 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 modifying 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 extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions attached to
the unit. Consult local building codes for special
requirements. In absence of local codes, it is
recommended that the USA standard ANSI/NFPA 70,
National Electrical Code (NEC), be followed.
It is important to recognize safety information. This is the
safety--alert symbol . When you see this symbol on the
unit and in instructions or manuals, be alert to the
potential for personal injury.
Understand the signal words DANGER, WARNING,
CAUTION, and NOTE. These words are used with the
safety-alert symbol. DANGER identifies the most serious
hazards which will result in severe personal injury or
death. WARNING signifies hazards which could result in
personal injury or death. CAUTION is used to identify
unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause in personal
injury or death.
Before performing service or maintenance operations
on unit, always turn off main power switch to unit and
install lockout tag. Unit may have more than one
power switch.
!WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause in personal
injury,death and/or equipment damage.
PuronR(R--410A) refrigerant systems operate at
higher pressures 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 in 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.
!WARNING
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
38AU units.
CAUTION
!
INSTALLATION GUIDELINE
Replacement/Retrofit — R--22 to PuronR
Replacement/retrofit installations require change-out of
outdoor unit, metering device, and filter driers.
Change-out of indoor coil (evaporator) and
interconnecting tubing is recommended.
Existing evaporator coil – If the existing evaporator coil
may be re-used, check with the coil manufacturer to verify
the coil construction is suitable for operation with the
higher pressures of PuronR(R-410A). Also determine if
the existing TXV valve is compatible with R-410A,
replace if necessary. The minimum factory test pressure
rating must be 1725 kPa (250 psig). Existing coil will
need to be purged with Nitrogen to remove as much
mineral oil as possible to eliminate cross contamination of
oils.
Acid test – If the existing system is being replaced
because of a compressor electrical failure, assume acid is
in system. If system is being replaced for any other
reason, use an approved acid test kit to determine 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.
Remove the suction line filter drier as soon as possible,
with a maximum of 72 hr 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.
Existing refrigeration piping – Reuse of existing refrigerant
piping involves three issues: quality (strength) of existing
tubing, cleanliness and tube size. Inspect all tube segments
and joints for signs of damage, corrosion or poor brazing.
Flush the interconnecting piping system with dry Nitrogen to
eliminate as much trace of mineral oil as possible.
38AU

3
Same tube sizes are capable of handling higher flowrates
(expressed as tons of cooling capacity) with Puron
refrigerant compared to R--22 at constant pressure drops.
For example, a 1/2--inch OD liquid line is rated at 33%
higher tons with PuronRthan with R--22 (at 5_F pressure
drop). A 1 1/8--inch OD suction line is rated at 53% higher
tons with Puron than with R--22 (at 2_F pressure drop).
Refrigeration lines selected for R--22 use are typically
oversized for Puron applications. Carefully check the
existing suction line size against the table for maximum size
(see Table 7); replace vertical riser segments if necessary.
Check existing liquid line size against sizing data in Table 5
or 6; replace with smaller lines when feasible.
Installation –
1. Remove the existing evaporator coil or fan coil and
install the replacement coil when appropriate.
2. Drain oil from low points and traps in suction line
tubing (and hot gas bypass tubing if appropriate) and
evaporator if they were not replaced. Removing oil
from evaporator coil may require purging of the
tubing with dry nitrogen.
3. Unless indoor unit is equipped with a Puron
approved metering device, change the metering
device to a thermal expansion valve (TXV) designed
for PuronR(R-410A).
4. Remove the existing outdoor unit. Install the new out-
door unit according to these installation instructions.
5. Install a new field-supplied liquid-line filter drier at
the indoor coil just upstream of the TXV or fix orifice
metering device.
6. If a suction line filter drier is also to be installed, in-
stall suction line drier downstream of suction line ser-
vice valve at condensing unit.
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 PuronRsystem.
CAUTION
!
7. If required, install a 100% activated alumina suction
line filter drier at the outdoor unit.
8. Evacuate and charge the system according to the in-
structions in this installation manual.
9. Operate the system for 10 hr. Monitor the pressure
drop across the suction line filter drier. If pressure
drop exceeds 21kPa (3 psig), 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 neces-
sary. Never leave suction-line filter drier in system
longer than 72 hr (actual time).
38AU

4
C101015
UNIT STD. UNIT WT. CORNER A CORNER B CORNER C CORNER D CENTER OF GRAVITY UNIT HEIGHT
kg. lbs. kg. lbs. kg. lbs. kg. lbs. kg. lbs. X Y Z H
38AUZ*07
(MCHX) 149 328 58 128 31 68 28 62 32 70 533.2 mm 21 in
482.6 mm
19 in
330.2 mm
13 in
1076.0 mm
42 3/8in
38AUZ*08
(MCHX) 160 353 63 138 33 72 29 65 35 78 482.6 mm 19 in
584.2 mm
23 in
330.2 mm
13 in
1076.0 mm
42 3/8in
38AUD*12
(MCHX) 226 499 88 193 50 111 38 72 56 123 508.0 mm 20 in
584.2 mm
23 in
381.0 mm
15 in
1279.2 mm
50 3/8in
38AUD*14
(MCHX) 229 505 86 190 40 88 34 76 68 151 508.0 mm 20 in
609.6 mm
24 in
381.0 mm
15 in
1279.2 mm
50 3/8in
38AUZ*07
(RTPF) 176 389 64 141 44 96 28 62 41 91 457.2 mm 18 in
609.6 mm
24 in
533.4 mm
21 in
1076.0 mm
42 3/8in
38AUZ*08
(RTPF) 177 391 64 142 44 96 28 62 41 91 457.2 mm 18 in
609.6 mm
24 in
533.4 mm
21 in
1076.0 mm
42 3/8in
38AUD*12
(RTPF) 234 516 84 185 53 117 38 83 59 131 482.6 mm 19 in
584.2 mm
23 in
609.6 mm
24 in
1279.2 mm
50 3/8in
LEGEND: MCXH = Novation™ coil
RTPF = Round Tube/Plate Fin coil
Fig. 1 -- 38AU Unit Dimensions
38AU

5
Table 1A — Physical Data — 38AUZ*07-08 Units — 50 Hz SI
UNIT SIZE 38AU Z*07 Z*08
NOMINAL CAPACITY (kW) 18 22
OPERATING WEIGHTS (kg)
NOVATIONCoil (Al Tube) 149 160
Round Tube/Plate Fin Coil (Cu/Al) 176 176
REFRIGERANT TYPE‡R-410A
NOVATION Operating Charge, Typical (kg)†3.8 4.6
NOVATION Shipping Charge (kg) 2.0 2.2
RTPF Operating Charge, Typical (kg)†6.4 7.7
RTPF Shipping Charge (kg) 5.0 5.9
COMPRESSOR
Qty...Type 1...Scroll 1...Scroll
Oil Charge (L) 1.7 1.8
CONDENSER FANS
Qty...r/s 2...15.3
Motor kW 0.43 0.40
Diameter (mm) 560
Nominal Airflow (L/s) 1950 3000
RTPF CONDENSER COIL
Material (Tube/Fin) Cu / Al
Coil Type 3/8--- i n R T P F
Rows/Fins per Meter (Fins/m) 2 / 670
Face Area (sq m total) 1.6 1.6
NOVATION CONDENSER COIL
Material (Tube/Fin) Al / Al
Coil Type Novation
Rows/Fins per Meter (Fins/m) 1 / 670
Face Area (sq m total) 1.6 1.9
CONTROLS
Pressurestat Settings (kPa)
High Cutout 4347 70
Cut-in 3482 138
Low Cutout 372 21
Cut-in 80734
PIPING CONNECTIONS (in. ODS)
Qty...Suction 1...11/81...11/8
Qty...Liquid 1...3/81...1/2
LEGEND
RTPF — Round Tube/Plate Fin
ODS — Outside Diameter Sweat (socket)
‡Unit is factory-supplied with partial charge only.
†Typical operating charge with 7.6 m (25 ft) of interconnecting piping.
38AU

6
Table 1B — Physical Data — 38AUZ*07-08 Units — 50 Hz English
UNIT SIZE 38AU Z*07 Z*08
NOMINAL CAPACITY (tons) 67.5
OPERATING WEIGHTS (lb)
NOVATIONCoil (Al Tube) 328 353
Round Tube/Plate Fin Coil (Cu/Al) 389 389
REFRIGERANT TYPE‡R-410A
NOVATION Operating Charge, Typical (lb)†8.4 10.2
NOVATION Shipping Charge (lb) 4.4 4.9
RTPF Operating Charge, Typical (lb)†14.0 17.0
RTPF Shipping Charge (lb) 11.0 13.0
COMPRESSOR
Qty...Type 1...Scroll 1...Scroll
Oil Charge (oz) 56 60
CONDENSER FANS
Qty...Rpm 2...920
Motor Watts 430 400
Diameter 22
Nominal Airflow (Cfm Total) 4150 6300
RTPF CONDENSER COIL
Material (Tube/Fin) Cu / Al
Coil Type 3/8--- i n R T P F
Rows/Fins per inch (FPI) 2/ 17
Face Area (sq ft total) 17.5 17.5
NOVATION CONDENSER COIL
Material (Tube/Fin) Al / Al
Coil Type Novation
Rows/Fins per inch (FPI) 1/17
Face Area (sq ft total) 17.5 20.5
CONTROLS
Pressurestat Settings (psig)
High Cutout 630 10
Cut-in 505 20
Low Cutout 54 3
Cut-in 117 5
PIPING CONNECTIONS (in. ODS)
Qty...Suction 1...11/81...11/8
Qty...Liquid 1...3/81...1/2
LEGEND
RTPF — Round Tube/Plate Fin
ODS — Outside Diameter Sweat (socket)
‡Unit is factory-supplied with partial charge only.
†Typical operating charge with 25 ft (7.6 m) of interconnecting piping.
38AU

7
Table 2A — Physical Data — 38AUD*12-14 Units — 50 Hz SI
UNIT SIZE 38AU D*12 D*14
NOMINAL CAPACITY (kW) 28 34
OPERATING WEIGHTS (kg)
NOVATIONCoil (Al Tube) 226 229
Round Tube/Plate Fin Coil (Cu/Al) 234 ---
REFRIGERANT TYPE‡R-410A
NOVATION Operating Charge A/B, Typical (kg)†3.4 / 3.3 4.8 / 4.9
NOVATION Shipping Charge A/B (kg) 1.3 / 1.3 1.5 / 1.5
RTPF Operating Charge A/B, Typical (kg)†5.0 / 5.0 ---
RTPF Shipping Charge A/B (kg) 3.6 / 3.6 ---
COMPRESSOR
Qty...Type 2...Scroll 2...Scroll
Oil Charge A/B (L) 1.2 1.7
CONDENSER FANS
Qty...r/s 2...15.3
Motor kW 0.40
Diameter (mm) 560
Nominal Airflow (l/s Total) 3000 2450
RTPF CONDENSER COIL
Material (Tube/Fin) Cu / Al ---
Coil Type 3/8--- i n R T P F ---
Rows/Fins per Meter (Fins/m) 2 / 670 ---
Face Area (sq m total) 2.3 ---
NOVATION CONDENSER COIL
Material (Tube/Fin) Al / Al
Coil Type Novation
Rows/Fins per Meter (Fins/m) 1 / 670
Face Area (sq m total) 2.3 3.0
CONTROLS
Pressurestat Settings (kPa)
High Cutout 4347 70
Cut-in 3482 138
Low Cutout 372 21
Cut-in 807 34
PIPING CONNECTIONS (in. ODS)
Qty...Suction A/B 1...11/8/ 1...11/81...13/8/ 1...13/8
Qty...Liquid A/B 1...3/8/ 1...3/81...1/2/ 1...1/2
LEGEND
RTPF — Round Tube/Plate Fin
ODS — Outside Diameter Sweat (socket)
‡Unit is factory-supplied with partial charge only.
†Typical operating charge with 7.6 m (25 ft) of interconnecting piping.
38AU

8
Table 2B — Physical Data — 38AUD*12-14 Units — 50 Hz English
UNIT SIZE 38AU D*12 D*14
NOMINAL CAPACITY (tons) 10 12.5
OPERATING WEIGHTS (lb)
NOVATIONCoil (Al Tube) 499 505
Round Tube/Plate Fin Coil (Cu/Al) 516 ---
REFRIGERANT TYPE‡R-410A
NOVATION Operating Charge A/B, Typical (lb)†7.4 / 7.3 10.8 / 10.9
NOVATION Shipping Charge A/B (lb) 3.0 / 3.0 3.5 / 3.5
RTPF Operating Charge A/B, Typical (lb)†11.0 / 11.0 ---
RTPF Shipping Charge A/B (lb) 8.0 / 8.0 ---
COMPRESSOR
Qty...Type 2...Scroll 2...Scroll
Oil Charge A/B (oz) 42 60
CONDENSER FANS
Qty...Rpm 2...920
Motor Watts 400
Diameter 22
Nominal Airflow (Cfm Total) 6300 5200
RTPF CONDENSER COIL
Material (Tube/Fin) Cu / Al ---
Coil Type 3/8--- i n R T P F ---
Rows/Fins per inch (FPI) 2/17 ---
Face Area (sq ft total) 25.1 ---
NOVATION CONDENSER COIL
Material (Tube/Fin) Al / Al
Coil Type Novation
Rows/Fins per inch (FPI) 1/17
Face Area (sq ft total) 25.0 31.8
CONTROLS
Pressurestat Settings (psig)
High Cutout 630 10
Cut-in 505 20
Low Cutout 54 3
Cut-in 117 5
PIPING CONNECTIONS (in. ODS)
Qty...Suction A/B 1...11/8/ 1...11/81...13/8/ 1...13/8
Qty...Liquid A/B 1...3/8/ 1...3/81...1/2/ ...11/2
LEGEND
RTPF — Round Tube/Plate Fin
ODS — Outside Diameter Sweat (socket)
‡Unit is factory-supplied with partial charge only.
†Typical operating charge with 25 ft (7.6 m) of interconnecting piping.
38AU

9
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
38AUDA14A0G9A0A0A0
Model Type Packaging
38AU = Carrier Condensing Unit 0 = Standard
Type of Coil Electrical Options
D = Dual Circuit, A/C Scroll Compressor
Z = Single Circuit, A/C Scroll Compressor A = None
C = Non-Fused Disconnect
1 = LTL
Service Options
0 = None
Nominal Capacity
07 = 18 kW (6 Tons)
08 = 22 kW (7.5 Tons)
Not Used
12 = 28 kW (10 Tons)
A = Place Holder
14 = 34 kW (12.5 Tons)
Base Unit Controls
0 = Electro-Mechanical Controls
Not Used
A = Not Used
Design Revision
Voltage
9 = 400/3/60
Refrigerant Options
A = None
B = Low Ambient
Not Used
0 = Not Used
Coil Options
Puron
®
R–410A Refrigerant
A = Initial Rev (Discrete Model Number)
NOVATION™
G = Al/Al
K = E-Coat Al/Al
T = Al/Al with Hail Guard
W = E-Coat Al/Al with Hail Guard
RTPF
A = Cu/Al
B = Precoat (Cu/Al)
C = E-Coat (Cu/Al)
N = Precoat (Cu/Al) with Hail Guard
P = E-Coat (Cu/Al) with Hail Guard
M = Cu/Al with Hail Guard
C101016
Fig. 2 -- Model Number Nomenclature
SETANGISEDNOITISOP
)radnelaclacsif(erutcafunamfokeeW1−2
)ASU,saxeT,PTE=G(noitacolgnirutcafunaM5
rebmunlaitneuqeS6−10
12345678910
0510G12345
POSITION NUMBER
TYPICAL
Year of manufacture (”10” = 2010)3−4
C10068
Fig. 3 -- Serial Number Nomenclature
Matching 38AU Model To Evaporator Coil
The Model 38AUZ is a single-circuit unit design,
requiring one set of refrigeration piping. This model can
be connected to an evaporator coil with one circuit or with
two circuits (by manifolding the evaporator connections
into a single piping system).
The Model 38AUD is a dual-circuit unit design that
requires two sets of refrigeration piping between the
outdoor unit and the evaporator coil (or coils). This model
can only be connected to an evaporator coil that has two
refrigeration circuits (or to two separate evaporator coils).
The Model 38AUD CANNOT be connected to a
single-circuit evaporator coil. The Model 38AUD
CANNOT be field-converted to a single-circuit design.
Table 3 – Evaporator Coil Connections
Evaporator Coil has Connect to Model Notes
Single Circuit 38AUZ ONLY
Two Circuits
38AUZ
Manifold evaporator
circuits into single
piping system
Or
38AUD Use two separate
piping systems
Before unpacking this new 38AU model, compare the
evaporator coil design to the 38AU model.
38AU

10
.INSTALLATION
Jobsite Survey
Complete the following checks before installation.
1. Consult local building codes or the U.S.A. National
Electrical Code (Ref: ANSI/NFPA 70, [American Na-
tional Standards Institute/National Fire Protection As-
sociation], latest revision) for special installation re-
quirements
2. Determine unit location (from project plans) or select
unit location.
3. Check for possible overhead obstructions which may
interfere 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.
NOTE: Local codes may require different clearances
than specified in Fig. 4. It is the responsibility of installers
to be knowledgeable in local codes and to modify the
recommended clearances to satisfy local codes.
NOTE: Consider also the effect of adjacent units on
airflow performance and control box safety clearance.
REAR:
Min 18” (457 mm)
requried for service
Note: Observe requirements for 39” (914 mm) operating clearance
on either Left or Rear coil opening.
RIGHT:
Min 18” (457 mm)
requried for service
LEFT:
Min 18” (457 mm)
requried for service FRONT:
42” (1067 mm)
C110201
Fig. 4 -- Service Clearance Dimensional Drawing
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 refrigeration piping, including suction riser
requirements (outdoor unit above indoor unit), liquid line lift
(outdoor unit below indoor unit) and hot gas bypass line.
Relocate sections to minimize the length of interconnecting
tubing.
DO NOT BURY REFRIGERATION LINES.
Although unit is weatherproof, avoid locations that permit
water from higher level runoff and overhangs to fall onto
the unit.
Step 2 — Complete Pre-Installation Checks
Check Unit Electrical Characteristics: Confirm before
installation of unit that voltage, amperage and circuit
protection requirements listed on unit data plate agree with
power supply provided.
Un--crate 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:
SConsult local building codes or the U.S.A. National
Electrical Code (Ref: ANSI/NFPA 70, [American
National Standards Institute/National Fire Protection
Association], latest revision) for special installation
requirements.
SAllow sufficient space for airflow clearance, wiring,
refrigerant piping, and servicing unit. See Fig. 1 for unit
dimensions and weight distribution data.
SLocate the unit so that the outdoor coil (condenser)
airflow is unrestricted on all sides and above.
SThe unit may be mounted on a level pad directly on the
base channels or mounted on raised pads at support
points. See Tables 1A through 2B for unit operating
weights. See Fig. 1 for weight distribution based on
recommended support points.
NOTE: If vibration isolators are required for a particular
installation, use the data in Fig. 1 to make the proper
selection.
Step 3 — Prepare Unit Mounting Support
Slab Mount —
Provide a level concrete slab that extends a minimum of
150 mm (6 in.) beyond unit cabinet. Install a gravel apron
in front of condenser coil air inlet to prevent grass and
foliage from obstructing airflow.
Step 4 — Rig and Mount the Unit
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
All panels must be in place when rigging. Unit is not
designed for handling by fork truck.
CAUTION
!
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
38AU

11
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
IMPORTANT: Do not bury refrigerant piping
underground.
IMPORTANT: A refrigerant receiver is not provided
with the unit. Do not install a receiver.
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.
Model 38AUD has two separate refrigeration systems. If
required, each circuit will require a field-supplied/installed
supplemental relief device.
Check 38AU Model with Evaporator Coil Connections —
Confirm before installation of unit that the evaporator coil
connections are consistent with this 38AU model. See
Table 3 on page 9.
Determine Refrigerant Line Sizes —
Select the recommended line sizes for 38AUZ and
38AUD unit from the appropriate tables.
Determine the linear length of interconnecting piping
required between the outdoor unit and indoor unit
(evaporator). Consider and identify also the arrangement
of the tubing path (quantity and type of elbows in both
lines), liquid line solenoid size, filter drier and any other
refrigeration specialties located in the liquid line. Refer to
the indoor unit installation instructions for additional
details on refrigeration specialties devices.
Determine equivalent line length adjustments for path and
components and add to linear line lengths. See Table 4,
Equivalent Lengths for Common Fittings, for usual fitting
types. Also identify adjustments for refrigeration
specialties. Refer to Part 3 of the Carrier System Design
Manual for additional data and information on equivalent
lengths.
Table 4 – Equivalent Lengths for Common Fittings
(EN units)
mm
Ref
Nominal
Tube OD
(in)
Elbows
90
Std
90
Lrad
90
Street
45
Std
45
Street
9.5 3/80.40 0.24 0.67 0.18 0.30
12.7 1/20.43 0.27 0.70 0.21 0.34
15.9 5/80.49 0.30 0.76 0.24 0.40
19.1 3/40.55 0.37 0.88 0.27 0.46
22.2 7/80.61 0.43 0.98 0.27 0.49
28.6 11/80.79 0.52 1.25 0.40 0.64
34.9 13/81.01 0.70 1.71 0.52 0.91
41.3 15/81.22 0.79 1.92 0.64 1.04
54.0 21/81.52 1.01 2.50 0.79 1.37
mm
Ref
Nominal
Tube OD
(in)
Tees
Branch
Flow
Straight-Thru
No
Reduct
Reduce
25%
Reduce
50%
9.5 3/80.79 0.24 0.34 0.40
12.7 1/20.82 0.27 0.37 0.43
15.9 5/80.91 0.30 0.43 0.49
19.1 3/41.07 0.37 0.52 0.55
22.2 7/81.22 0.43 0.58 0.61
28.6 11/81.52 0.52 0.70 0.79
34.9 13/82.13 0.70 0.94 1.01
41.3 15/82.44 0.79 1.13 1.22
54.0 21/83.05 1.01 1.43 1.52
NOTE: Equivalent line lengths will vary based on tube
diameter. Calculate equivalent line length for each pipe by
adding equivalent length adjustments to linear lengths for
each pipe.
Enter the appropriate table to select the recommended line
sizes.
Model: Line Sizes Table Quantity of Line Sets
38AUZ 5 1
38AUD 6 2
Liquid Lift —
A liquid lift condition exists when the outdoor unit is located
below the indoor (evaporator) unit and liquid flows vertically
up in a portion of the liquid line. The vertical column of
liquid reduces the available state point subcooling at the
evaporator coil’s thermal expansion valve. This effect
reduces the length of liquid lift (feet of elevation) that a
liquid line size can accommodate. Longer linear tube lengths
will also reduce the amount of liquid lift possible.
Check Tables 5 (38AUZ) and 6 (38AUD) for maximum
liquid lift capabilities for line sizes. Reselect the liquid line
tube size if necessary. If maximum available tube size
cannot provide the required lift distance on this installation,
relocate the outdoor unit to reduce the equivalent line length
or the lift requirement.
38AU

12
Table 5 – 38AUZ 07-08 50Hz Piping Recommendations (Single-Circuit Unit)
R---410A Equivalent Length
meter 0 --- 1 2 12---23 23--- 34 34---46 46---57
feet 0 --- 3 8 38---75 75---113 113---150 150--- 188
Model
Linear Length
meter 0 --- 7 . 5 7.5---15 15--- 23 23---30 30--- 38
feet 0 --- 2 5 25---50 50--- 75 75---100 100---125
38AUZ*07 Liquid Line 3/83/81/23/81/23/81/23/81/2
Max Lift
SI (m)
Novation 7.5 15 16 23 9 29 10 34
RTPF 7.5 15 19 23 12 30 11 38
EN (ft)
Novation 25 50 53 75 34 97 33 112
RTPF 25 50 63 75 42 100 38 125
Suction Line 7/87/87/87/87/81 --- 1/8
Charge
SI (kg)
Novation 3.8 4.4 4.9 5.9 5.4 6.8 6.1 7.9
RTPF 6.4 7.0 7.4 8.5 7.9 9.3 8.7 10.4
EN (lbs)
Novation 8.4 9.8 10.8 13.1 11.8 14.9 13.5 17.4
RTPF 14.0 15.4 16.4 18.7 17.4 20.5 19.1 23.0
38AUZ*08 Liquid Line 1/21/25/81/25/81/25/81/25/8
Max Lift
SI (m)
Novation 7.5 911 7 10 DNU 10 10 16
RTPF 7.5 15 NR 23 NR 27 30 18 38
EN (ft)
Novation 25 30 38 24 36 DNU 35 33 53
RTPF 25 50 NR 75 NR 89 100 62 125
Suction Line 7/87/81 --- 1/81 --- 1/81 --- 1/8
Charge
SI (kg)
Novation 5.5 6.3 7.2 7.4 8.6 DNU 9.9 9.1 11.2
RTPF 8.6 9.4 NR 10.4 NR 11.3 13.0 12.2 14.3
EN (lbs)
Novation 12.2 13.9 15.8 16.2 19.0 DNU 21.9 20.0 24.8
RTPF 19.0 20.7 NR 23.0 NR 24.9 28.7 26.8 31.6
Legend:
Equivalent
Length Equivalent tubing length, including effects of refrigeration specialties devices
Linear Length Linear tubing length, feet
Liquid Line Tubing size, inches OD.
Max Lift Maximum liquid lift (indoor unit ABOVE outdoor unit only), at maximum permitted liquid line pressure drop
SLinear Length Less than 30 m (100 ft): Minimum 1.1° C (2.0° F) subcooling entering TXV
SLinear Length Greater than 30 m (100 ft): Minimum 0.3° C (0.5° F) subcooling entering TXV
Suction Line Tube size, inches OD
Charge Charge Quantity, lbs. Calculated for both liquid line sizes (where applicable), but only with larger suction line size
(where applicable)
DNU Do Not Use (pressure drop exceeds available subcooling in this model)
NR Not Recommended (use smaller liquid tube size)
SI Metric units of measure
EN English units of measure (I---P)
NOTE: For applications with equivalent length greater than 57 m (188 ft) and/or linear length greater than 38 m (125 ft),
contact your local Carrier representative.
38AU

13
Table 6 – 38AUD 12-14 50Hz Piping Recommendations (Two-Circuit Unit)
NOTE: 38AUD requires TWO sets of refrigeration piping
R---410A Equivalent Length
meter 0 --- 1 2 12---23 23--- 34 34---46 46---57
feet 0 --- 3 8 38---75 75---113 113---150 150--- 188
Model
Linear Length
meter 0 --- 7 . 5 7.5---15 15--- 23 23---30 30--- 38
feet 0 --- 2 5 25---50 50--- 75 75---100 100---125
38AUD*12 Liquid Line 3/83/83/81/23/81/23/81/2
Max Lift
SI (m)
Novation 7.5 15 15 23 10 24 13 29
RTPF 7.5 15 15 23 10 27 11 32
EN (ft)
Novation 25 50 50 75 36 79 44 96
RTPF 25 50 50 75 36 89 39 106
Suction Line 7/87/87/87/81 --- 1/8
Charge
SI (kg)
Novation 3.3 3.8 4.2 5.3 4.7 6.1 5.1 6.9
RTPF 4.9 5.4 5.8 6.9 6.3 7.7 6.8 8.6
EN (lbs)
Novation 7.3 8.3 9.3 11.6 10.3 13.4 11.3 15.2
RTPF 10.9 11.9 12.9 15.2 13.9 17.0 14.9 18.8
38AUD*14 Liquid Line 3/81/25/81/25/81/25/81/25/8
Max Lift
SI (m)
Novation 7.5 13 15 12 14 11 14 17 20
EN (ft)
Novation 25 45 50 42 49 39 48 56 68
Suction Line 7/87/87/81 --- 1/81 --- 1/8
Charge
SI (kg)
Novation 4.6 5.8 6.6 6.6 7.8 7.6 10.7 9.4 12.0
EN (lbs)
Novation 10.1 12.7 14.6 14.5 17.3 16.8 23.5 20.7 26.4
Legend:
Equivalent
Length Equivalent tubing length, including effects of refrigeration specialties devices
Linear Length Linear tubing length, feet
Liquid Line Tubing size, inches OD.
Max Lift Maximum liquid lift (indoor unit ABOVE outdoor unit only), at maximum permitted liquid line pressure drop
SLinear Length Less than 30 m (100 ft): Minimum 1.1° C (2.0° F) subcooling entering TXV
SLinear Length Greater than 30 m (100 ft): Minimum 0.3° C (0.5° F) subcooling entering TXV
Suction Line Tube size, inches OD
Charge Charge Quantity, lbs. Calculated for both liquid line sizes (where applicable), but only with larger suction line size
(where applicable)
DNU Do Not Use (pressure drop exceeds available subcooling in this model)
NR Not Recommended (use smaller liquid tube size)
SI Metric units of measure
EN English units of measure (I---P)
NOTE: For applications with equivalent length greater than 57 m (188 ft) and/or linear length greater than 38 m (125 ft),
contact your local Carrier representative.
38AU

14
Suction Riser —
A suction riser condition exists when the outdoor unit is
located above the indoor (evaporator) unit and suction
vapor must flow vertically up to return to the compressor.
Oil return is a concern when the suction tube size is too
large to produce the minimum refrigerant velocity to
ensure oil return at minimum load conditions.
Check Table 7 for maximum suction tube size for 38AU
units at minimum load conditions. Consider suction speed
riser (reduced tube size for vertical segment only) or
double suction riser arrangement if the proposed suction
tube size does not provide necessary minimum flowrates
for this riser.
Table 7 – 38AU Maximum Suction Pipe Size
Model: Unit Size Maximum Tube Size
38AUZ 07 13/8
08 15/8
38AUD 12 13/8
14 13/8
Vertical Separation (outdoor unit above indoor unit) –
Vertical elevation difference of 60 m (200 ft) is permitted
when the outdoor unit (38AUZ or 38AUD) is located
above the indoor unit.
Insulate Suction Lines —
Apply closed-cell tubular insulation to all suction lines
between evaporator coil connection and 38AU unit’s
suction service valve.
Hot Gas Bypass —
Hot gas bypass, if used, should be introduced before the
evaporator. (A bypass route that also bypasses the
evaporator circuit may lead to oil trapping in the
evaporator circuit during low load conditions and then to
oil slugging as evaporator load increases.) Model 38AU
units do not include a hot gas stub connection; a tee must
be field-supplied and installed in the compressor discharge
line. Run a 1/2-in OD line between outdoor unit and
evaporator coil inlet. Install an Auxiliary Side Connector
at the evaporator between TXV and distributor (follow
instructions for the side connector part). Insulate the hot
gas line.
38AUD: Generally only one hot gas bypass system will be
applied on a two-circuit unit. Connect the hot gas bypass
system to Circuit 1 (first-on/last-off, connected to the
evaporator coil’s bottom circuit).
38AUD Piping Connections —
The 38AUD’s two circuits are designated Circuit 1 and
Circuit 2. Circuit 1 is controlled by the thermostat’s Y1
(or TC1) contact and will be the first circuit on and last
circuit off. Circuit 2 is controlled by the thermostat’s Y2
(or TC2) contact and this circuit is always the “lag”
circuit.
See Fig. 5 for location of Circuit 1 and Circuit 2 service
valves and field piping connections. Circuit 1 is on the
right-hand side of the service valve compartment; Circuit
2isontheleft.
When a single piece evaporator coil with two separate
circuits is connected to a 38AUD, the lower coil circuit
should be connected to the 38AUD’s Circuit 1 so that the
evaporator’s lower coil segment is first-on/last-off (to
avoid re-evaporation of condensate on dry lower coil
segments).
Circuit 1
Connections
Circuit 2
Connections
CKT
2CKT
1
C10912
Fig. 5 -- 38AUD Service Valve Locations
Plan the Circuit 1 and Circuit 2 tubing segments carefully,
mark each segment and check constantly as piping
systems are assembled to avoid piping errors.
38AUD unit cannot be field-piped as a
single-circuit/tandem system.
Connecting 40RU to 38AUD: The 40RU fan coil in sizes
12, 14 and 16 is a face-split coil design that also has its
circuits designated as 1 and 2. See Fig. 6. Note that the
lower coil segment changes as the arrangement of the
40RU changes. In a vertical arrangement, the 40RU’s
lower coil segment is segment 2; this segment should be
connected to the 38AUD’s Circuit 1. In a horizontal
arrangement, the 40RU’s lower segment is now segment
1; this segment should be connected to the 38AUD’s
Circuit 1.
Note that refrigerant suction piping should be insulated.
40RU
Arrangement
Cooling
Stage
40RU Coil
Segment
Connect to
38AUD
Vertical Y1
Y2
2
1
Circuit 1
Circuit 2
Horizontal Y1
Y2
1
2
Circuit 1
Circuit 2
38AU

15
FIRST ON/LAST OFF = 2
VERTICALINSTALLATION
FIRS T O N/LA ST OF F = 1
HORIZONTAL INSTALLATION
1
2
2
1
C10071
Fig. 6 -- Typical Evaporator Coil Connections (40RU)
Install Filter Drier(s) and Moisture Indicator(s) —
Every unit MUST have a filter drier in the liquid line.
38AUD models require two filter driers (one in each
liquid line). Locate the filter drier(s) at the indoor unit,
close to the evaporator coil’s thermal expansion valve
(TXV) inlets.
38AU units include one (38AUZ) or two (38AUD)
Puron-duty filter drier(s), shipped in cartons attached to the
unit basepan. Remove the filter drier(s) and prepare to install
in the liquid line(s) at the evaporator coil. Do not remove
connection fitting plugs until ready to connect and braze the
filter drier into the liquid line position.
Table 8 – Puron-duty Filter Drier(s)
Model-Size Qty Liquid
Line OD
Desiccant
Volume
Part
Number Ref
38AUZ*07 13/8-in 8cu.in. KH43LS091
38AUZ*08 11/2-in 16 cu. in. KH43LS085
38AUD*12 23/8-in 8cu.in. KH43LS091
38AUD*14 21/2-in 16 cu. in. KH43LS085
Installation of liquid line moisture indicating sightglass in
each circuit is recommended. Locate the sightglass(es)
between the outlet of the filter drier and the TXV inlet.
Refer to Table 9 for recommendations on refrigeration
specialties.
In some applications, depending on space and
convenience requirements, it may be desirable to install 2
filter driers and sight glasses in a single circuit
application. One filter drier and sight glass may be
installed at A locations (see Fig. 7) or 2 filter driers and
sight glasses may be installed at B locations (see Figs. 7
and 8).
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 suction lines at the outdoor unit.
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
A LOCATION
SIGHT
GLASSES
B LOCATION
TXV
CKT 2
FILTER DRIER
A LOCATION
FILTER
DRIERS
B LOCATION
FLOW
TXV
SENSING
BULB
TXV
CKT 1
8 DIAMS
MIN
15 DIAMS
MIN 10
DIAMS
Single Circuit Coil Piping Configuration
For single compressor condensing units
Dual Circuit Coil Piping Configuration
For single compressor condensing units
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
LIQUID LINE
SOLENOID
VALVE
FLOW
LIQUID LINE
SOLENOID
VALVE
C10202
Fig. 7 -- Location of Sight Glass(es) and Filter Driers
Typical 38AUZ Systems
Table 9 – Refrigerant Specialties Part Numbers
LIQUID LINE
SIZE (in.)
LIQUID LINE
SOLENOID VALVE (LLSV)
LLSV
COIL
SIGHT
GLASS
FILTER
DRIER
3/8EF680033 EF680037 KM680008 provided with unit
see Table 8
1/2EF680035 EF680037 KM680004
38AUD units require TWO sets of parts.
38AU

16
AIRFLOW
SUCTION
CIRCUIT 2
SUCTION
CIRCUIT 1
AIRFLOW
15 DIAMS
MIN 10
DIAMS
8 DIAMS
MIN
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT
GLASSES
TXV
CKT 2
FILTER
DRIERS
LIQUID LINE
SOLENOID VALVE
CIRCUIT 2
FLOW
LIQUID LINE
SOLENOID VALVE
CIRCUIT 1
FLOW
TXV
SENSING
BULB
TXV
CKT 1
8 DIAMS
MIN
15 DIAMS
MIN 10
DIAMS
Dual Circuit Coil Piping Configuration
For two circuit condensing units
C10072
Fig. 8 -- Location of Sight Glasses and Filter Driers
Typical 38AUD Systems
Install Liquid Line Solenoid Valve —
It is recommended that a solenoid valve be placed in the
main liquid line (see Figs. 7 & 8) between the condensing
unit and the evaporator coil. Locate the solenoid valve at
the outlet end of the liquid line, near the evaporator coil
connections, with flow direction arrow pointed at the
evaporator coil. Refer to Table 9. (A liquid line solenoid
valve is required when the liquid line length exceeds 23 m
[75 ft].) This valve prevents refrigerant migration (which
causes oil dilution) to the compressor during the off cycle,
at low outdoor ambient temperatures.
Solenoid drop control wiring: control the power to the
liquid line solenoid through a Solenoid Valve Relay (SVR)
in all units. Use part number HN61PC005 (field--supplied,
installed). 38AUZ unit requires one SVR; 38AUD unit
requires two relays.
38AUD units also require a separate control power
transformer for the liquid solenoid valve loads. Use
transformer part number HT01BD602, according to unit
power supply.
Mount the SVR (and transformer TRAN3 when used) in
unit control box. Connect per wiring schematic label on
unit or per Fig. 24 (38AUZ) or Fig. 25 (38AUD).
Capacity Control Liquid Line Solenoid Valve:
Evaporator capacity staging control via direct thermostat
control of a liquid solenoid valve on the evaporator’s
second stage circuit is not possible with 38AU models. If
this installation is a retrofit for a unit that included
automatic pressure--operated unloading, check the existing
thermostat and liquid solenoid valve wiring for possible
direct thermostat control of a solenoid valve; re--wire per
Figs. 12 or 13 and 24 or 25.
Selecting an Accumulator –
Because all 38AU models use scroll compressors, an
accumulator is not required. If an accumulator is to be
added, check the accumulator manufacturer’s literature
carefully for indication of its suitability for use with
R--410A; look for minimum working pressure of 1380 kPa
(200 psig). Select the accumulator first on the basis of its
cataloged minimum capacity (tons) to ensure oil return from
the accumulator, then on tube size or holding capacity.
Make Piping Connections —
Piping connections at the 38AU unit are ball valves with
stub tube extensions. Do not open the unit service valves
until all interconnecting tube brazing has been completed.
The stub tube connections include 1/4-in SAE service
fittings with Schrader valve cores (see Fig. 9). 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 prevent the
formation of copper oxides inside the tubes at brazed
joints.
Factory
High-Flow
A
ccess Port
Service Valve
with Stem Cap
Field Service
Access Port
(Schrader core)
Sweat
Connection
C10203
Fig. 9 -- Typical Piping Connection Assembly
When connecting the field tubing to the 38AU service
valves, wrap the valves in wet rags to prevent overheating
Pressure-test all joints from outdoor unit connections over
to the evaporator 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 23-34 N-cm
(2-3 in-lbs).
Evacuation/Dehydration —
Evacuate and dehydrate the connected refrigeration
system(s) (excluding the 38AU unit) to 500 microns using
a two-stage vacuum pump attached to the service ports
outside the 38AU service valves, following description in
GTAC II, Module 4, System Dehydration.
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
PuronR(R--410A) refrigerant systems operate at
higher pressure than standard R--22 systems. Do not
use R--22 service equipment or components on Puron
refrigerant equipment.
!WARNING
38AU

17
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 cylinders. 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 position (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 recommended that refrigerant always be removed
from the cylinder as a liquid. Admit liquid refrigerant into
the system in the discharge line. If adding refrigerant into
the suction line, use a commercial 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.
Preliminary Charge —
Before starting the unit, charge R-410A liquid refrigerant
into the high side of each 38AU circuit through the liquid
service valve(s). The amount of refrigerant added must be
at least 80% of the operating charge listed in Tables 5 or 6
for LINEAR line length LESS the factory charge quantity
(if factory shipping charge has not been removed). See
example below.
Allow high and low side pressures to equalize. If pressures
do not equalize readily, charge R-410A vapor (using special
service manifold with expansion device) into the suction 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 Reclamation for liquid charging
procedures.
Example (using Tables 5 and 6):
Unit 38AUZA08 with Novation coil
Linear line length 25 m
Estimated equivalent line length 37 m (add 50% to linear
length)
Liquid lift 8 m (indoor unit above outdoor unit)
See Table 5, 38AUZ models, for line sizes and system
operating charge. Enter table in Equivalent Length column
for 34-46 m.
Liquid line size: Note that a DNU code (Do Not Use)
applies to 1/2-in. OD tube with Novation coil option for
unit 38AUZ*08. Check liquid lift capability of 5/8-in OD
tube against project requirements. Table 5 indicates 5/8-in
tube allows 10 m lift which exceeds job requirements.
(Note: If maximum liquid lift value is not greater than
project requirements, STOP. Select a new location for the
outdoor unit that reduces lift and/or length requirements
or select a unit model with RTPF coil option.)
Suction line size: Select 1-1/8-in. OD tube for this line
length.
Note Operating Charge quantity: 9.9 kg.
Start-up Charge Calculation
Target start-up charge quantity is 80% of Operating
Charge quantity:
Start-up Charge = 0.80 x 9.9 = 7.9 kg (use for recharge
situation)
Deduct Shipping Charge if still available (new unit
installation):
Shipping Charge (from Table 1A): 2.2 kg
Field-Add for Start-up: 7.9 – 2.2 = 5.7 kg (use for new
unit installation)
EN Units:
38AUZA08 with Novation coil
Linear length 82 ft
Equivalent length 123 ft
Liquid lift 25 ft
Select liquid line as 5/8-in OD, suction line as 1-1/8-in OD.
Note Operating Charge quantity: 21.9 lbs
Start-up Charge Calculation
Target start-up charge quantity is 80% of Operating
Charge quantity:
Start-up Charge = 0.80 x 21.9 = 17.5 lbs (use for
recharge situation)
Deduct Shipping Charge if still available (new unit
installation):
Shipping Charge (from Table 2A): 4.6 lbs
Field-Add for Start-up: 17.5 – 4.6 = 12.9 lbs (use for
new unit installation)
38AU

18
Step 6 — Install Accessories
Accessories requiring modifications to unit wiring should
be completed now. These accessories may include Winter
Start controls and Low Ambient controls. Refer to the
instructions shipped with the accessory.
Step 7 — Complete Electrical Connections
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 connected to unit ground lug
in control compartment, or conduit approved for
electrical ground when installed in accordance with
local electrical codes or in absence of local codes, it is
recommended that the U.S.A. standard ANSI/NFPA
70, National Electrical Code (NEC), be followed.
!WARNING
NOTE: Check all factory and field electrical connections
for tightness. Field-supplied wiring shall conform with the
limitations of 33C(63F) rise.
Field Power Supply —
Field power wires are connected to the unit at line-side
pressure lugs on compressor contactor C and TB1 (see
wiring diagram label for control box component
arrangement) or at factory-installed option non-fused
disconnect switch. Max wire size is #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 optional disconnect switch. These leads are
for factory run-test purposes only; remove and discard
before connecting field power wires to unit connection
points. Make field power connections directly to line
connection pressure lugs only.
FIRE HAZARD
Failure to follow this warning could cause in personal
injury, death and/or equipment damage.
Do not connect aluminum wire between disconnect
switch and condensing unit. Use only copper wire.
(See Fig. 10.)
!WARNING
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
A93033
Fig. 10 -- Disconnect Switch and Unit
Units Without Factory-Installed Disconnect —
When installing units, provide a disconnect switch of
adequate size per local or national wiring code.
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 access panel.
All Units —
All field wiring must comply with all local codes. Size wire
based on MCA (Minimum Circuit Amps) on the unit
informative plate. See Fig. 11 for power wiring connections
to the unit load terminals and equipment ground.
Provide a ground--fault and short--circuit over--current
protection device (fuse or breaker) per local code (or in
absence of local code, is is recommended that U.S.A.
standard, NEC Article 440, be followed). Refer to unit
informative data plate for MOCP (Maximum
Over--current Protection) device size.
All field wiring must comply with the appropriate national
electrical codes and local requirements.
Affix the crankcase heater warning sticker to the unit
disconnect switch.
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. See
Tables 11 and 12. On 3-phase units, voltages between
phases must be balanced within 2% and the current within
10%. Use the formula shown in the legend for Tables 11
and 12 Note 3 (see page 21) 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.
38AU

19
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
11 13
L1 L2 L3
C1 TB1
Disconnect
C10074
Fig. 11 -- Power Wiring Connections
Table 10 – American/European Wire Conversions
AMERICAN EUROPEAN
Industry
Standard Size
American Conversion
Size (mm2)
Industry Standard
Size (mm2)
20 AWG 0.52 0.5
18 AWG 0.82 1.0
16 AWG 1.30 1.5
14 AWG 2.08 2.5
12 AWG 3.30 4.0
10 AWG 5.25 6.0
8AWG 6.36 10.0
6AWG 13.29 16.0
4AWG 21.14 25.0
3AWG 26.65 —
2AWG 33.61 35.0
1AWG 42.39 50.0
1/0 AWG 53.49 —
2/0 AWG 67.42 70.0
3/0 AWG 85.00 95.0
4/0 AWG 107.9 120.0
Field Control Wiring —
38AU unit control voltage is 24 v. See Fig. 24 (38AUZ)
and Fig. 25 (38AUD) for typical field control connections
and the unit’s label diagram for field-supplied wiring
details. Route control wires to the 38AU unit through the
opening in unit’s end panel to the connections 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 (air handler or packaged fan coil). Fig. 12 (38AUZ)
and Fig. 13 (38AUD) depict typical connections to a Carrier
40RU 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 38AU unit requires an external temperature control
device. This device can be a thermostat (field-supplied) or
a PremierLink controller (available as a field-installed
accessory, for use on a Carrier Comfort Network or as a
stand alone control).
Note 1: Connect only if thermostat requires 24-vac power source.
Note 2: Connect W1 and W2 if supplemental heaters are installed
Field Wiring
(Note 1)
(Note 2)
(Note 2)
C10985
Fig. 12 -- Typical Remote Thermostat Connections
— 38AUZ
Note 1: Typical multi-function marking. Follow manufacturer’s configuration
instructions to select Y2.
Note 2: Connect only if thermostat requires 24-vac power source.
Note 3: Connect W1 and W2 if supplemental heaters are installed
Field Wiring
(Note 1)
(Note 2)
(Note 3)
(Note 3)
C10078
Fig. 13 -- Typical Remote Thermostat Connections
— 38AUD
38AU

20
Thermostat —
Install a Carrier-approved accessory thermostat according
to installation instructions included with the accessory.
Locate the thermostat accessory on a solid wall in the
conditioned space to sense average temperature in
accordance with the thermostat installation instructions.
38AUZ Unit -- 38AUZ unit is a single--stage cooling unit. If
no economizer function is required, select a single--stage
cooling thermostat. If an integrated economizer function is
required, select a two--stage cooling thermostat.
The 38AUD is a dual--circuit, two-stage cooling unit.
Select a two—stage cooling thermostat.
Select a thermostat cable or equivalent single leads of
different colors with minimum of four leads for 38AUZ or
five leads for 38AUD unit. Check the thermostat installation
instructions for additional features which might require
additional conductors in the cable.
For wire runs up to 15 m (50 ft.), use no. 18 AWG
(American Wire Gage) insulated wire (35C minimum).
For15to23m(50to75ft.),useno.16AWGinsulated
wire (35C minimum). For over 23 m (75 ft.), use no. 14
AWG insulated wire (35C minimum). All wire sizes
larger than no. 18 AWG cannot be directly connected to
the thermostat and will require a junction box and splice
at the thermostat.
PremierLink (accessory installation) – Refer to Form
33CS-58SI for details on connecting the PremierLink
controller and its various sensors.
Control Circuit Wiring —
Control voltage is 24 v. See Fig. 24 and Fig. 25 and the
unit’s label diagram for field--supplied wiring details.
Route control wires through the opening in unit’s end
panel to the connection in the unit’s control box.
Control Transformer Wiring —
On multi voltage units, check the transformer primary
wiring connections. See Fig. 14 or refer to the unit’s label
diagram.
C10079
Fig. 14 -- Control Transformer Wiring
38AU