Carrier 38AU User Manual

38AU

Air-Cooled Condensing Units
50 Hz

®

with Puron

(R-410A) Refrigerant

Sizes 07 - 14

Installation, Start-Up and

Service Instructions

CONTENTS

SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . 1

INSTALLATION GUIDELINES. . . . . . . . . . . . . . . . . . . . . . . 2

INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19

Step 1 – Plan for Unit Location . . . . . . . . . . . . . . . . . . . 9

Step 2 – Complete Pre-Installation Checks. . . . . . . . . . 9

Step 3 – Prepare Unit Mounting Support . . . . . . . . . . 9

Step 4 – Rig and Mount the Unit . . . . . . . . . . . . . . . . . . 9

Step 5 – Complete Refrigerant Piping Connections

Step 6 – Install Accessories. . . . . . . . . . . . . . . . . . . . . . 14

Step 7 – Complete Electrical Connections . . . . . . . . . 14

PRE-START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Turn On Crankcase Heater . . . . . . . . . . . . . . . . . . . . . . 19

Preliminary Charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

START-UP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 -25

38AU Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

OPERATING SEQUENCE. . . . . . . . . . . . . . . . . . . . . . . . . . 26

Indoor (Supply) Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Cooling, Unit Without Economizer . . . . . . . . . . . . . . . . 26

Cooling, Unit With Economizer. . . . . . . . . . . . . . . . . . . 26

Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

ROUTINE SYSTEM MAINTENANCE. . . . . . . . . . . . . . . 26

Quarterly Inspection (and 30 days after initial start)

Seasonal Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 26

SERVICE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 - 33

Refrigeration System . . . . . . . . . . . . . . . . . . . . . . . . . 27

Compressor Oil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Servicing Systems on Roofs with

Synthetic Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Liquid Line Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . 27

Filed Refrigerant Access Ports . . . . . . . . . . . . . . . . . 27

Factory High-flow Access Ports . . . . . . . . . . . . . . . . 27

Comfort Alert Diagnostic Module. . . . . . . . . . . . . . . 28

Crankcase Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Compressor Protection. . . . . . . . . . . . . . . . . . . . . . . . . . 30

Low-Pressure Switches . . . . . . . . . . . . . . . . . . . . . . . . . 30

High-Pressure Switches. . . . . . . . . . . . . . . . . . . . . . . . . 30

Outdoor Fans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

NOVATION™ Coil Cleaning and Maintenance . . . . 33

. . 10

. . 26

Repairing NOVATION Condenser Tube Leaks . . . . 33

Replacing NOVATION Condenser Coil . . . . . . . . . . 33

Service Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

Fastener Torque Values . . . . . . . . . . . . . . . . . . . . . . . 333

TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . 34 -35

APPENDIX A

Air Conditioner and Heat Pump with Puron

Quick Reference Guide . . . . . . . . . . . . . . . . . . . . . . . 36

APPENDIX B

Wiring Diagram List. . . . . . . . . . . . . . . . . . . . . . . . . 36

APPENDIX C

Motormaster Sensor Locations. . . . . . . . . . . . . . . . . 37

START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . .CL-1, CL-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/
NFPA70, 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 safety­alert 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 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.

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
pressures than standard R-22 systems. Do not use R-22
service equipment or components on Puron refrigerant
equipment.

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.

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.

INSTALLATION GUIDELINE

Replacement /Retrofit – R22 to Puron

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 Puron
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.

®

(R-410A). Also determine if the existing TXV valve

®

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 suction­line 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 (to facilitate
evacuation of the system’s low side when suction filter-drier is
removed).

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 Puron® (R-410A).

4. Remove the existing outdoor unit. Install the new outdoor
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 fil.ter-drier is also to be installed, install
the suction line filter-drier immediately upstream of the
suction line service valve at the outdoor unit. Note the
recommendation above regarding use of ball valve in the
liquid line.

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.

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
instructions 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 necessary. Never leave
suction-line filter drier in system longer than 72 hr.

2

UNIT

Standard

Weight

Corner

A

Corner

B

Corner

C

Corner

D

Center of Gravity Unit Height

lbs. kg. lbs. kg. lbs. kg. lbs. kg. lbs. kg. X Y Z H

38AUZ*07

328 149 128 58 68 31 62 28 70 32

21.00

[533.4]

19.00

[482.6]

13.00

[330.2]

42.36

[1076.0]

38AUZ*08

353 160 138 63 72 33 65 29 78 35

19.00

[482.6]

23.00

[584.2]

13.00

[330.2]

42.36

[1076.0]

38AUD*12

499 226 193 88 111 50 72 38 123 56

20.000
[508.0]

23.00

[584.2]

15.00

[381.0]

50.36

[1279.2]

38AUD*14

505 229 190 86 88 40 76 34 151 68

20.000
[508.0]

24.00

[609.6]

15.00

[381.0]

50.36

[1279.2]

Fig. 1 — 38AU*07-14 Unit Dimensions

3

Table 1A — Physical Data — 38AUZ*07-08 Units — 50 Hz English

UNIT SIZE 38AU Z*07 Z*08
NOMINAL CAPACITY (tons)
OPERATING WEIGHTS (lb)

Aluminum-Fin Coils 328 353

REFRIGERANT TYPE

Operating Charge, Typical (lb)

‡

†

Shipping Charge (lb) 4.4 4.9

COMPRESSOR

Qty...Type 1...Scroll

OUTDOOR FANS

Qty...Rpm 2...1100
Motor Hp
Diameter 22
Nominal Airflow (Cfm Total) 6000
Watts (Total) 610

OUTDOOR COIL (Qty)

Face Area (sq ft total) 17.5 20.5
Rows/Fins per inch (FPI) 1/17 1/17

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...1
Qty...Liquid

67.5

R-410A

9.0 12.3

1

/

4

1...NOVATION

1

1...

/

8

3

/

8

1...11/

1...1/

8

2

LEGEND
ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.
† Typical operating charge with 25 ft of interconnecting piping.

4

Table 1B — Physical Data — 38AUZ*07-08 Units — 50 Hz SI

UNIT SIZE 38AU Z*07 Z*08
NOMINAL CAPACITY (kW)
OPERATING WEIGHT (kg)

Aluminum-Fin Coils 149 160

REFRIGERANT TYPE

Operating Charge, Typical (kg)

‡

†

Shipping Charge (kg) 2.0 2.2

COMPRESSOR

Qty...Type 1...Scroll

OUTDOOR FANS

Qty...r/s 2...18
Motor Hp NEMA

Diameter (mm) 560
Nominal Airflow (L/s) 2832
Watts (Total) 610

OUTDOOR COIL (Qty)

Face Area (sq m total) 1.6 1.9
Rows/Fins per Meter (Fins/m) 1...670 1...670

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...1
Qty...Liquid

21.1 26.4

R-410A

4.1 5.6

1

/

4

1...NOVATION

1

1...

/

8

3

/

8

1...11/

1...1/

8

2

LEGEND

NEMA — National Electrical Manufacturers Association
ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.
† Typical operating charge with 7.62 m of interconnecting piping.

5

Table 2A — Physical Data — 38AUD*12-14 Units — 50 Hz English

UNIT SIZE 38AU D*12 D*14
NOMINAL CAPACITY (tons)
OPERATING WEIGHTS (lb)

Aluminum-Fin Coils 418 431

REFRIGERANT TYPE

Operating Charge A/B, Typical (lb)

‡

†

Shipping Charge A/B (lb) 3.0/3.1 3.7/3.9

COMPRESSOR

Qty...Type 2...Scroll

OUTDOOR FANS

Qty... RPM 2...1100
Motor Hp
Diameter (in) 22
Nominal Airflow (Cfm Total) 6,000
Watts (Total) 610

OUTDOOR COIL (Qty)

Face Area (sq ft total) 25.0 31.8
Rows/Fins per inch (FPI) 1/17 1/17

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...1
Qty...Liquid A/B

10 12.5

R-410A

7.5/7.5 11.2/11.2

1

/4

1...NOVATION

1

1...

/8 /1...11/

3

/8 /1...3/

8

8

1...13/8 /1...13/

1...1/2 /1...1/

8

2

LEGEND
ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.
† Typical operating charge with 25 ft of interconnecting piping.

6

Table 2B — Physical Data — 38AUD*12-14 Units — 50 Hz SI

UNIT SIZE 38AU D*12 D*14
NOMINAL CAPACITY (kW)
OPERATING WEIGHT (kg)

Aluminum-Fin Coils 190 196

REFRIGERANT TYPE

Operating Charge A/B, Typical (kg)

‡

†

Shipping Charge A/B (kg) 1.3/1.4 1.7/1.8

COMPRESSOR

Qty...Model 2...Scroll

OUTDOOR FANS

Qty... r/s 2...18
Motor Hp NEMA
Diameter (mm) 560
Nominal Airflow (Cfm Total) 6,000
Watts (Total) 610

OUTDOOR COIL (Qty)

Face Area (sq m total) 2.3 3.0
Rows/Fins per Meter (Fins/m) 1...670 1...670

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...1
Qty...Liquid A/B

35.1 44

R-410A

3.4/3.4 5.1/5.1

1

/

4

1...NOVATION

1

1...

/8 /1...11/

3

/8 /1...3/

8

8

1...13/8 /1...13/

1...1/2 /1...1/

8

2

LEGEND

NEMA — National Electrical Manufacturers Association
ODS — Outside Diameter Sweat (socket)

‡ Unit is factory-supplied with partial charge only.
† Typical operating charge with 7.62 m of interconnecting piping.

7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

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POSITION NUMBER
TYPICAL

Year of manufacture (”09” = 2009)3−4

38AUZA07A0G9–0A0A0

_____________ ____

Model Type Packaging

38AU= Carrier Condensing Unit
Puronr

R---410A Refrigerant

0=Standard

1=LTL

Type o f Co il

Z = Single Circuit, A/C Scroll Compressor
D = Dual Circuit, A/C Scroll Compressor

Refrigerant Options

A = None
B = Low Ambient

Nominal Tonnage

07 = 6 Tons
08 = 7.5 Tons
12 = 10 Tons
14 = 12.5 Tons

Factory Assigned

A=Default

Factory Assigned

0=Default

Coil Options (Condenser)

G = Al/Al Standard
K = E-Coated Al/Al
T = Al/Al with Louvered Hail Guard
W = E-Coated Al/Al with Louvered Hail Guard

Electrical Options

A=None

C = Non-Fused Disconnect

Service Options

1=
0=None

Factory Assigned

A = Default

Base Unit Controls

0 = Electro-Mechanical Controls

Design Rev

--- = Catalog Model Number
A = Initial Rev (Discrete Model Number)

Voltage

9 = 400/3/50

Fig. 2 — Model Number Nomenclature

Fig. 3 — Serial Number Nomenclature

8

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.

Before unpacking this new 38AU model, compare the evapora­tor coil design to the 38AU model.

Table 3 — Evaporator Coil Connections

Evaporator Coil has Connect to Model Notes

Single Circuit 38AUZ ONLY

Manifold evaporator
circuits into single
piping system

Use two separate
piping systems

Two Circuits

38AUZ

Or

38AUD

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 National
Standards Institute/National Fire Protection Association],
latest version) for special installation requirements.

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 minimum working space, clearances be­tween live electrical components and nearest barriers (ground­ed or ungrounded), clearances for 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.

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.

RIGHT:

REAR:
Min 457 mm (18”)
requried for service

LEFT:
Min 457 mm (18”)
requried for service

Note: Observe requirements for 914 mm (39”) operating clearance
on either Left or Rear coil opening.

Fig. 4 — Service Clearance Dimensional Drawing

Min 457 mm (18”)
requried for service

FRONT:
1067 mm (42”)

Step 2 — Complete Pre-Installation Checks

CHECK UNIT ELECTRICAL CHARACTERISTIC —
Confirm before installation of unit that voltage, amperage and
circuit 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,
refrigerant piping, and servicing unit. See Fig.1 for unit
dimensions 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 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.

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

9

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

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 — The 38AU unit is provided
with a fusible joint in the suction line in accordance with
applicable UL standards for pressure 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.

Table 4 — Equivalent Lengths for Common Fittings (ft)

Nominal
Tub e OD

3

/

8

1

/

2

5

/

8

3

/

4

7/

8

1

1

/

8

3

1

/

8

5

1

/

8

1

2

/

8

Nominal
Tub e OD

3

/

8

1

/

2

5

/

8

3

/

4

7/

8

1

1

/

8

3

1

/

8

5

1

/

8

1

2

/

8

90° Std 90° Lrad 90° Street 45° Std 45° Street

1.3 0.8 2.2 0.6 1

1.4 0.9 2.3 0.7 1.1

1.6 1 2.5 0.8 1.3

1.8 1.2 2.9 0.9 1.5
2 1.4 3.2 0.9 1.6

2.6 1.7 4.1 1.3 2.1

3.3 2.3 5.6 1.7 3
4 2.6 6.3 2.1 3.4
5 3.3 8.2 2.6 4.5

Branch

Flow

2.6 0.8 1.1 1.3

2.7 0.9 1.2 1.4

3.5 1.2 1.7 1.8

10 3.3 4.7 5

No Reduct Reduce 25% Reduce 50%

31 1.41.6

41.4 1.9 2
5 1.7 2.3 2.6
7 2.3 3.1 3.3

82.6 3.7 4

Elbows

Tees

Straight-Thru

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.

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.

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 recommended suction tube size does
not provide necessary minimum flowrates for this riser.

10

Table 5 — 38AUZ 07-08 Piping Recommendations (Single-Circuit Unit)

R-410A Equivalent Length

Ft 0-38 38-75 75-113 113-150 150-188
m 0-12 12-23 23-34 34-46 46-57

Model Typ Linear ft 0-25 25-50 50-75 75-100 100-125
38AUZ*07 Liquid Line

3

/

8

3

1

/

8

1

/

/

2

2

1

5

/

2

1

/

8

5

/

/

2

8

Max Lift 25 42 50 75 90 100 86 101
Suction Line

7

/

1-1/

8

7

/

8

1-1/81-1/

8

8

1-1/

8

1-1/

8

Charge (lbs) 8.4 9.6 11.1 13.1 15.0 18.8 16.9 22.6

38AUZ*08 Liquid Line

1

/

2

1

/

2

1

/

2

1

/

2

1

/

2

Max Lift 25 50 75 100 112
Suction Line

8

1-1/81-1/

8

1-1/

8

1-1/

8

1-1/

8

7

/

Charge (lbs) 11.8 9.6 12.9 16.8 18.7

Legend:

Length Equiv Equivalent tubing length, including effects of refrigeration specialties devices
Liquid Line Tubing size, inches OD.
Max Lift

Cooling

Heating
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

NOTE:

Maximum liquid lift at maximum permitted liquid line pressure drop

• Indoor unit ABOVE outdoor unit

• Indoor unit BELOW outdoor unit

applicable)
For applications with linear length greater than 100 ft (30.5 m), contact your local Carrier representative.

Table 6 — 38AUD 12-14 Piping Recommendations (Two-Circuit Unit)

NOTE: 38AUD requires TWO sets of refrigeration piping
R-410A Equivalent Length

Ft 0-38 38-75 75-113 113-150 150-188
m 0-12 12-23 23-34 34-46 46-57

Model Typ Linear ft 0-25 25-50 50-75 75-100 100-125
38AUD*12 Liquid Line

3

/

8

3

/

8

3

1

/

8

1

/

/

2

2

1

/

2

Max Lift 25 50 28 75 100 99
Suction Line

7

/

8

7

/

8

11/

8

11/

8

11/

8

Charge ea. (lbs) 7.1 8.1 9.6 11.9 13.8 15.8

38AUD*14 Liquid Line

3

/

8

3

/

8

3

1

/

8

1

/

/

2

2

1

/

2

Max Lift 25 50 48 75 100 122
Suction Line

7

/

8

7

/

8

11/

8

11/

8

11/

8

Charge ea. (lbs) 9.7 10.7 12.2 14.5 16.4 18.4

Legend:

Length Equiv Equivalent tubing length, including effects of refrigeration specialties devices
Liquid Line Tubing size, inches OD.
Max Lift

Cooling

Heating
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

NOTE:

Maximum liquid lift at maximum permitted liquid line pressure drop

• Indoor unit ABOVE outdoor unit

• Indoor unit BELOW outdoor unit

applicable)
For applications with linear length greater than 100 ft (30.5 m), contact your local Carrier representative.

Table 7 — 38AU Maximum Suction Pipe Size

Model: Unit Size Maximum Tube Size

3

38AUZ 07 1

08 15/

38AUD 12 13/

14 15/

/

8

8

8

8

11

INSULATE SUCTION LINES — Apply closed-cell tubular

Circuit A

Connections

Circuit B

Connections

FIRST ON/LA ST OFF = B

VERTICAL INSTALLATION

FIRS T ON/LAST OF F = A

HORIZONTAL INSTALLATION

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 field­supplied and installed in the compressor discharge line. Run a
½-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 A (first-on/last-off, connected to the
evaporator coil’s bottom circuit).

38AUD PIPING CONNECTIONS – The 38AUD’s two
circuits are designated Circuit A and Circuit B. Circuit A is
controlled by the thermostat’s Y1 (or TC1) contact and will be
the first circuit on and last circuit off. Circuit B is controlled by
the thermostat’s Y2 (or TC2) contact and this circuit is always
the “lag” circuit.

See Fig. 5 for location of the Circuit A and Circuit B service
valves and field piping connections. Circuit A is on the right­hand side of the service valve compartment; Circuit B is on the
left.

40RU
Arrangement

Vertical

Horizontal

Cooling

Stage

Y1
Y2

Y1
Y2

40RU Coil

Segment

B
A

A
B

Connect to

38AUD

Circuit A
Circuit B

Circuit A
Circuit B

Fig 5 - 38AUD Service Valve Locations

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 A so that the evaporator’s
lower coil segment is first-on/last-off (to avoid re-evaporation
of condensate on dry lower coil segments).

Plan the Circuit A and Circuit B 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 A and B. 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 B; this segment should be connected to the 38AUD’s
Circuit A. In a horizontal arrangement, the 40RU’s lower
segment is now segment A; this segment should be connected
to the 38AUD’s Circuit A.

Fig. 6 — Typical Evaporator Coil Connections (40RU)

Note that refrigerant suction piping should be insulated.
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

38AUZ*07 1
38AUZ*08 1
38AUD*12 2
38AUD*14 2

Liquid

Line OD

3

/8-in 8 cu. in. KH43LG091

1

/2-in 16 cu. in. KH43LG085

3

/8-in 8 cu. in. KH43LG091

1

/2-in 16 cu. in. KH43LG085

Desiccant

Vol ume

Part

Number Ref

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.

12

Table 9 — Refrigerant Specialities Part Numbers.

LEGEND

TXV — Thermostatic Expansion Valve

LIQUID LINE

SIZE (in.)

3

/

8

1

/

2

5

/

8

LIQUID LINE

SOLENOID VALVE (LLSV)

ALC-066208 AMG-24/50-60 HMI-1TT3
ALC-066209 AMG-24/50-60 HMI-1TT4
ALC-066212 AMG-24/50-60 HMI-1TT5

38AUD units require TWO sets of parts.

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 in Fig. 7, or 2 filter driers
and sight glasses may be installed at B locations.

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.

INSTALL LIQUID LINE SOLENOID VALVE —
It is recommended that a solenoid valve be placed in the main
liquid line (see Fig. 7) 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. Wire the
solenoid in parallel with the compressor contactor coil (see
Fig. 7). This means of electrical control is referred to as sole­noid drop control.

CAPACITY CONTROL LIQUID LINE SOLENOID VALVE
Evaporator capacity control via liquid solenoid valve is not rec­ommended for use with 38AU models.

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 as been completed.

The stub tube connections include ¼-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.

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 soap­and-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).

LLSV
COIL

SIGHT

GLASS

FILTER

DRIER

Provided with unit

See Table 8

8 DIAMS

MIN

8 DIAMS

MIN

8 DIAMS

EQUALIZER LINE

TXV

EQUALIZER LINE

TXV

CKT 2

SIGHT
GLASSES
B LOCATION

TXV

CKT 1

MIN

SIGHT GLASS
A LOCATION

SIGHT GLASS
A LOCATION

FILTER
DRIERS
B LOCATION

INDOOR
COIL CKT

AIRFLOW

INDOOR
COIL CKT 2

AIRFLOW

INDOOR
COIL CKT 1

AIRFLOW

TXV
SENSING
BULB

15 DIAMS

10

MIN

DIAMS

Single Circuit Coil Piping Configuration

For single compressor condensing units

TXV
SENSING
BULB

15 DIAMS

10

MIN

DIAMS

TXV
SENSING
BULB

15 DIAMS

10

MIN

DIAMS

Dual Circuit Coil Piping Configuration

For single compressor condensing units

Fig. 7 — Location of Sight Glass(es) and Filter Driers

Typical 38AUZ Systems

FILTER DRIER
A LOCATION

DROP
CONTROL
SOLENOID
VALVE

FILTER DRIER
A LOCATION

DROP
CONTROL
SOLENOID
VALVE

FLOW

FLOW

13

INDOOR
COIL CKT 2

AIRFLOW

SUCTION
CIRCUIT B

SUCTION
CIRCUIT A

AIRFLOW

15 DIAMS

MIN

10

DIAMS

8 DIAMS

MIN

TXV
SENSING
BULB

EQUALIZER LINE

SIGHT
GLASSES

TXV

CKT B

FILTER
DRIERS

DROP CONTROL
SOLENOID VALVE
CIRCUIT B

FLOW

DROP CONTROL
SOLENOID VALVE
CIRCUIT A

FLOW

TXV
SENSING
BULB

TXV

CKT A

8 DIAMS

MIN

15 DIAMS

MIN

10

DIAMS

Dual Circuit Coil Piping Configuration

For two circuit condensing units

LEGEND

TXV — Thermostatic Expansion Valve

Factory
High-Flow
Access Port

Service Valve
with Stem Cap

Field Service
Access Port
(Schrader core)

Sweat
Connection

Fig. 8 — Location of Sight Glass(es) and Filter Driers

Typical 38AUD Systems

Example:
38AUZ*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 5 (38AUZ):

Liquid
Suction 1-

1

/2 in

1

/8 in.

Charge 12.9 lbs (at 75-ft linear length)

80% of Operating Charge:

0.80 x 12.9 = 10.3 lbs
Factory Shipping Charge: 4.9 lbs
Field-charge quantity: 10.3 lbs – 4.9 lbs = 5.4 lbs
For applications with linear line lengths greater than 100 ft

(30.5 m), contact your local Carrier representative.

Step 6 — Install Accessories

Accessories requiring modifications to unit wiring should be
completed now. These accessories may include Winter Start
controls, Low Ambient controls, phase monitor, Compressor
LOCout. Refer to the instructions shipped with the accessory.

Step 7 — Complete Electrical Connections

Fig. 9 — Typical Piping Connection Assembly

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.

Puron® (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.

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.

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.

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 —

If equipped with optional Powered Convenience Outlet: The
power source leads to the convenience outlet's transformer pri­mary are not factory connected. Installer must connect these
leads according 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 and indoor fan contactor IFC
pressure lugs with unit field power leads.

All units are factory wired for the voltage shown on the name­plate. Refer to unit label diagram for additional information.

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. Use copper
conductors only.

14

NOTE: TEST LEADS - Unit may be equipped with short

COPPER

WIRE ONLY

ELECTRIC

DISCONNECT

SWITCH

ALUMINUM

WIRE

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 result in intermittent
operation or performance satisfaction.

Do not connect aluminum wire between disconnect switch
and condensing unit. Use only copper wire.

(See Fig.10.)

Units Without Disconnect Option

CTB1

11 13

Disconnect

per

NEC

L1

L2 L3

208/230-3-60

460-3-60
575-3-60

Units With Disconnect Option

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 NEC and 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 power terminal block and equipment ground.

Provide a ground-fault and short-circuit over-current protection
device (fuse or breaker) per NEC Article 440 (or local codes).
Refer to unit informative data plate for MOCP (Maximum
Over-current Protection) device size.

L1

L2

L3

2

4

6

Optional

Disconnect

Switch

1

3

5

Factory

Wiring

Disconnect factory test leads; discard.

Fig.11 — Power Wiring Connections

Table 10 — American/European Wire Conversions

AMERICAN EUROPEAN

Industry

Standard Size

20 AWG 0.52 0.5
18 AWG 0.82 1.0
16 AWG 1.30 1.5
14 AWG 2.08 2.5

American

Conversion (mm

2

)

European

Standard Size (mm2)

All field wiring must comply with the NEC and local
requirements.

Affix the crankcase heater warning sticker to the unit
disconnect switch.

Convenience Outlets —

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal
injury or death.

Units with convenience outlet circuits may use multiple
disconnects. Check convenience outlet for power status
before opening unit for service. Locate its disconnect
switch, if appropriate, and open it. Tag-out this switch, if
necessary.

Two types of convenience outlets are offered on 38AU 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. 12.

15

Convenience

UNIT

VOLTAGE

CONNECTASPRIMARY

CONNECTIONS

TRANSFORMER

TERMINALS

208,

230

240

L1: RED + YEL
L2: BLU + GRA

H1 + H3
H2 + H4

460 480

L1: RED
Splice BLU +
YEL
L2: GRA

H1

H2 + H3

H4

575 600

L1: RED
L2: GRA

H1
H2

Outlet

GFCI

Pwd-CO

Fuse

Switch

Control Box

Access Panel

Fig. 12 — 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 factory­installed 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. 12.

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 unit­mounted 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. 13.

Duty Cycle: The unit-powered convenience outlet has a duty
cycle limitation. The transformer is intended to provide power
on an intermittent basis for service tools, lamps, etc; it is not
intended to provide 15-amps loading for continuous duty loads
(such as 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).

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.

Pwd-CO

Transformer

Fig. 13 - Powered Convenience Outlet Wiring

Fuse on power type: The factory fuse is a Bussman “Fusetron”
T-15, non-renewable screw-in (Edison base) type plug fuse.

Using unit-mounted convenience outlets: Units with unit­mounded 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 and local codes, for use of convenience outlets.

Installing Weatherproof Cover –

A weatherproof while-in-use cover for the factory-installed
convenience outlets is required. This cover cannot be
factory-mounted due to its depth; it must be installed at unit
installation. For shipment, the convenience outlet is covered
with a blank cover plate.

The weatherproof cover kit is shipped in the unit's control box.
The kit includes the hinged cover, a backing plate and gasket.

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
approximately
Press the gasket over the screw heads. Slip the backing plate
over the screw heads at the keyhole slots and align with the
gasket; tighten the two screws until snug (do not over-tighten).

Mount the weatherproof cover to the backing plate as shown in
Fig. 14. Remove two slot fillers in the bottom of the cover to
permit service tool cords to exit the cover. Check for full
closing and latching.

16

1

/2-in (13 mm) under screw heads are exposed.

Fig. 14 — Weatherproof Cover Installation

RECEPTACLE
NOT INCLUDED

COVER – WHILE-IN-USE
WEATHERPROOF

BASE PLATE FOR
GFCI RECEPTACLE

Note 1: Typical multi-function marking. Follow manufacturer’s configuration
instructions to select Y2.

Note 2: Y2 to economizer required on single-stage cooling units when
integrated economizer function is desired

Note 3: Connect only if thermostat requires 24-vac power source.
Note 4: Connect W1 and W2 if supplemental heaters are installed
Field Wiring

R

Y1

G

O/B/Y2

C

W2

W1

(Notes 1, 2)

(Note 3)

(Note 4)

(Note 4)

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

R

Y1

G

O/B/Y2

C

W2

W1

(Notes 1)

(Note 3)

(Note 3)

(Note 3)

All Units —

Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. See Tables
10 and 11. 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 10 and 11, Note 5 (see
page 19) 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.

Field Control Wiring — 38AU unit control voltage is 24 v.
See Figs 23 and 24 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). Figs 15 (38AUZ)
and 16 (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).

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.

38AUD Unit – 38AUD unit is a 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 unit or five
leads for 38AUD units. 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). For 15 to 23 m
(50 to 75 ft.), use no. 16 AWG insulated 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 33CS­58SI for details on connecting the PremierLink controller and
its various sensors.

Fig. 15 — Typical Remote Thermostat Connections

— 38AUZ

Fig. 16 — Typical Remote Thermostat Connections

— 38AUD

17

External Devices – The 38AU control transformers provide 24-

Example: Supply voltage is 230-3-60

AB = 224 v
BC = 231 v
AC = 226 v

Average Voltage =

(224 + 231 + 226)

=

681

3

3

=227

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.

%VoltageImbalance =100 x

4

227

=1.76%

This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.

IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.

% Voltage Imbalance = 100 x

max voltage deviation from average voltage

average voltage

v NEC Class 2 power sources to energize external control de­vices. These devices will include the indoor fan motor contac­tor (or control relay). These devices may also include liquid
line solenoid valve (two on 38AUD model), economizer con­trol relay, supplemental electric heater contactors or control re­lays and other devices selected by system designer.

Control transformer TRAN1 provides control power through
terminal R to C on the CTB’s field connection terminal strip for
supply fan motor interlock. This source may also be used to en-

Table 11 — Electrical Data — 38AUZ*07-08 60 Hz Units

ergize economizer control relay and electric heater contactors
or relays. Maximum available power is 20 va. Check concur­rent loadings by external control devices. If the maximum con­current loading exceeds 20 va, purchase and install the accesso­ry Transformer-Relay package (available for 208/230 and
460-v units).

Control transformer TRAN3 provides control power through
terminals A1 (9) and A2 (10) to C for liquid line solenoids.
Maximum available power is 40 va. These outputs are
switched ON/OFF by the Solenoid Valve Relays.

UNIT
SIZE

38AU

Z*07

Z*08

UNIT

SIZE

38AU

D*12

D*14

LEGEND AND NOTES FOR TABLES 11 & 12
FLA —
LRA —
MCA —
MOCP —

NEC —
RLA —

‡

Units are suitable for use on electrical systems where voltage supplied to

the unit terminals is not below or above the listed limits.

NOTES:

1. The MCA and MOCP values are calculated in accordance with the NEC,
Article 440.

2. Motor RLA and LRA values are established in accordance with
Underwriters’ Laboratories (UL), Standard 1995.

3. The 575-v units are UL, Canada-listed only.

4. Convenience outlet is available as a factory-installed option and is 115-v,
1 ph, 60 Hz.

NOMINAL
VOLTAGE

V-Ph-Hz MIN MAX RLA LRA WATTS FLA QTY MCA MOCP MCA MOCP

400-3-50 380 420 9.7 64 270 0.7 2 13.5 20 15.9 25

400-3-50 380 420 12.2 101 270 0.7 2 16.7 25 19.0 30

NOMINAL
VOLTAGE

V-Ph-Hz MIN MAX RLA LRA RLA LRA WATTS FLA QTY MCA MOCP MCA MOCP

208/230-3-60 380 420 7.8 51.5 7.8 51.5 270 0.7 2 19.0 25 21.3 30

208/230-3-60 380 420 10.6 74 10.6 74 270 0.7 2 25.3 30 27.6 30

Full Load Amps
Locked Rotor Amps
Minimum Circuit Amps
Maximum Overcurrent

Protection
National Electrical Code
Rated Load Amps

VOLTAGE

RANGE

VOLTAGE

RANGE

‡

COMPRESSOR

OUTDOOR

FAN MOTORS (ea)

WITHOUT POWERD

Table 12 — Electrical Data — 38AUD*12-14 60 Hz Units

COMPRESSOR 1COMPRESSOR

‡

2

OUTDOOR

FAN MOTORS (ea)

5. Unbalanced 3-Phase Supply Voltage

Never operate a motor where a phase imbalance in supply voltage is
greater than 2%. Use the following formula to determine the percentage
of voltage imbalance.

CONVENIENCE

OUTLET

WITHOUT POWERD

CONVENIENCE

OUTLET

WITH POWERD
CONVENIENCE

OUTLET

WITH POWERD
CONVENIENCE

OUTLET

18

PRE-START-UP

START-UP

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.

UNIT DAMAGE HAZARD

Do not attempt to start the condensing unit, even
momentarily, until the following steps have been
completed. Compressor damage may result.

System Check

1. Check all air handler(s) and other equipment auxiliary
components. 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
nameplate rating.

7. The crankcase heater must be firmly attached to the com­pressor 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 crankcase heater, proceed as follows:

1. Set the space thermostat set point above the space tem­perature 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(s) through the liquid service valve(s). The
amount of refrigerant added must be at least 80% of the
operating charge listed in the Physical Data table (Tables 1A
through 2B, pages 4 through 7). Open the liquid line and
suction line service valves. Allow high and low side pressures
to equalize before starting compressor. If pressures do not
equalize readily, charge vapor on 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.

UNIT DAMAGE HAZARD

Prior to starting compressor, a preliminary charge of
refrigerant must be added to avoid possible compressor
damage.

38AU Units

The compressor crankcase heater(s) 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 24­hour 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 38AU units are factory charged with the
required amount of oil. If recharging in required, use
Emkarate RL 32-3MAF for the 38AU units.

Compressor Rotation

On 3-phase units with scroll compressors, it is important to be
certain that the compressor is rotating in the proper direction.
38AU units are equipped with a Comfort Alert Diagnostic
Module (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 gages to the suction and liquid pressure
fittings.

2. Energize the compressor.

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, disconnect the electrical power to the unit and
check the circuit through the overload with an ohmmeter or
continuity tester.

19

Advanced Scroll Temperature Protection (ASTP)

0

10

20

30

40

50

60

70

80

90

100

110

120

0 102030405060708090

Compressor Unloaded Run Time (Minutes)

Recommended Cooling Time

(Mi

nut

es)

*Times are approximate.
NOTE: Various factors, including high humidity, high ambient tem-

perature, and the presence of a sound blanket will increase cool­down times.

A label located above the terminal box identifies Copeland
Scroll compressor models that contain this technology. See Fig.

17. Advanced Scroll Temperature Protection (ASTP) is a form
of internal discharge temperature protection, that unloads the
scroll compressor when the internal temperature reaches ap­proximately 300°F. At this temperature, an internal bi-metal
disk valve opens and causes the scroll elements to separate,
which stops compression. 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. 18.

Fig. 17 — Advanced Scroll Temperature

Protection Label

Start Unit

Set the space thermostat to a set point above space temperature
so that there is no demand for cooling. Close the 38 AU discon­nect switch. Only the crankcase heater will be energized.

Reset the space thermostat below space temperature so that a
call for cooling is ensured.

Never charge liquid into the low-pressure side of 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 Motormaster
or mild-ambient control function.

Adjust Refrigerant Charge

The unit must be charged in Cooling mode only. Refer to Cool­ing Charging Charts, Fig. 19 through Fig. 22. Vary refrigerant
until the conditions of the chart are met. Note that the charging
charts are different from the type normally used. The charts are
based on charging the units to the correct subcooling for the
various operating conditions. Accurate pressure gage and tem­perature sensing device are required. Connect the pressure
gage to the service port on the liquid line service valve. Mount
the temperature sensing device on the liquid line close to the
liquid line service valve, and insulate 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.

Fig. 18 — 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 automatically before the motor protector resets, which
may take up to 2 hours.

FINAL CHECKS

Ensure that all safety controls are operating, control panel
covers are on, and the service panels are in place.

20

Fig. 19 — 38AUZ*07 Charging Chart

Fig. 20 — 38AUZ*08 Charging Chart

21

Fig. 21 — 38AUD*12 Charging Chart

22

Fig. 22 — 38AUD*14 Charging Chart

23

Fig. 23 — Typical 38AUZ Wiring Diagram (50Hz Single Circuit Unit Shown)

24

Fig. 24 — Typical 38AUD Wiring Diagram (50Hz Dual Circuit Unit Shown)

25

OPERATING SEQUENCE

ROUTINE SYSTEM MAINTENANCE

Base Unit Controls

Indoor (Supply) Fan

The indoor fan contactor (IFC) is remotely located at the fan
coil or fan section. If the thermostat fan operation is selected as
Continuous, the IFC is energized and the indoor (supply) fan
motor runs continuously. If the thermostat fan operation is
selected as Automatic, the IFC will be energized on a call for
Cooling; indoor (supply) fan motor runs. When thermostat call
for Cooling is satisfied, the IFC is de-energized and indoor
(supply) fan motor stops.

Cooling, Unit Without Economizer

On a thermostat call for Cooling, IFC will be energized and
indoor (supply) fan motor runs. Thermostat contact TC1
closes; terminal Y1 at 38AU unit receives 24-v. 24-v received
at CADM terminal Y. If anti-recycle time delay period has not
expired, CADM relay will remain open, preventing
compressor start. When safety pressure switches are closed, the
liquid line solenoid valve opens. When CADM time delay
expires, the compressor contactor is energized; both outdoor
fan motors start and compressor starts.

38AUD Second-Stage Cooling —
On a thermostat calling for Stage 2 Cooling, thermostat contact
TC2 closes; terminal Y2 at 38AUD unit receives 24-v. 24-v
received at CADM2 terminal Y. If anti-recycle time delay
period has not expired, CADM relay will remain open,
preventing compressor start. When safety pressure switches are
closed, the liquid line solenoid valve opens. When CAMD time
delay expires, the compressor contactor C2 is energized;
Compressor B starts.

When space cooling load is satisfied, thermostat contacts TC1
open, removing 24-v at 38AU terminal Y1. Compressor and
outdoor fan motors stop. Liquid line solenoid valve is
de-energized and valve closes. CADM begins its three-minute
anti-recycle time delay.

If either the Low Pressure Switch or High Pressure Switch
opens while thermostat contact TC1 (or TC2 on 38ARD)
remains closed, the compressor contactor is de-energized (both
fan motors and compressor stop) and liquid line solenoid is de­energized (valve closes). CADM initiates a TRIP event
(cooling demand sensed at CADM terminal Y but no current is
measured at T1, T2, T3 motor sensors); CADM relay opens
and RED LED is illuminated. TRIP condition maintains
lockout of compressor operation until CADM is manually
reset. Reset CADM by cycling unit main power.

Complete system shutdown may be caused by loss of main
power, open compressor internal overload, open low-pressure
or high-pressure switch, or a fault detected by the CADM
logic. Compressor operation without cooling may indicate the
compressor’s ASTP feature is active (unit sizes 12 and 14
only); disconnect unit power and allow compressor to cool. See
Service section for further details.

Cooling, Unit With Economizer

Refer to fan coil unit installation instructions and economizer
accessory installation instructions for operating sequences
when system is equipped with accessory economizer.

Heating

Refer to fan coil unit installation instructions and accessory
heating device installation instructions for operating sequences
in heating mode.

These items should be part of a routine maintenance program,
to be checked every month or two, until a specific schedule for
each can be identified for this installation:

Quarterly Inspection
(and 30 days after initial start)

Indoor section

• Condenser coil cleanliness checked.

• Return air filter replacement

• Outdoor hood inlet filters cleaned

• Belt tension checked

• Belt condition checked

• Pulley alignment checked

• Fan shaft bearing locking collar tightness checked

• Condensate drain checked

Seasonal Maintenance

These items should be checked at the beginning of each season
(or more often if local conditions and usage patterns dictate):

Air Conditioning

• Condenser fan motor mounting bolts tightness

• Compressor mounting bolts

• Condenser fan blade positioning

• Control box cleanliness and wiring condition

• Wire terminal tightness

• Refrigerant charge level

• Evaporator coil cleaning

• Evaporator blower motor amperage

Heating

• Power wire connections

• Fuses ready

• Manual-reset limit switch is closed

Economizer or Outside Air Damper

• Inlet filters condition

• Check damper travel (economizer)

• Check gear and dampers for debris and dirt

26

SERVICE

1/2-20 UNF RH

30°

0.596

.47

5/8” HEX

SEAT

CORE

WASHER

DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY

7/16-20 UNF RH

O-RING

45°

1/2" HEX

This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.

(Part No. EC39EZ067)

Refrigeration System

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in damage to
equipment.

This system uses Puron® refrigerant which has higher
pressures than R-22 and other refrigerants. No other refrig­erant may be used in this system. Gage set, hoses, and re­covery system must be designed to handle Puron®. If you
are unsure consult the equipment manufacturer.

Compressor Oil —

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in damage to
equipment.

The compressor in a Puron system uses a polyolester
(POE) oil. This oil is extremely hygroscopic, meaning it
absorbs water readily. POE oils can absorb 15 times as
much water as other oils designed for HCFC and CFC re­frigerants. Take all necessary precautions to avoid exposure
of the oil to the atmosphere.

Servicing Systems on Roofs With Synthetic
Materials —

known to cause long term damage to some synthetic roofing
materials. Exposure, even if immediately cleaned up, may
cause embrittlement (leading to cracking) to occur in one year
or more. When performing any service which may risk expo­sure of compressor oil to the roof, take appropriate precautions
to protect roofing. Procedures which risk oil leakage include
but are not limited to compressor replacement, repairing refrig­erants leaks, replacing refrigerant components such as filter
drier, pressure switch, metering device, coil, accumulator, or
reversing valve.

SYNTHETIC ROOF PRECAUTIONARY PROCEDURE

1. Cover extended roof working area with an impermeable
polyethylene (plastic) drop cloth or tarp. Cover an ap­proximate 3.3 x 3.3 m (10 x 10 ft) area.

2. Cover area in front of the unit service panel with a terry
cloth shop towel to absorb lubricant spills and prevent

POE (polyolester) compressor lubricants are

run-offs, and protect drop cloth from tears caused by tools
or components.

3. Place terry cloth shop towel inside unit immediately un­der component(s) to be serviced and prevent lubricant
run-offs through the louvered openings in the base pan.

4. Perform required service.

5. Remove and dispose of any oil contaminated material per
local codes.

Liquid Line Filter Drier — The factory-provided filter

drier is specifically designed to operate with Puron®. Replace
the filter drier with factory-authorized components only with a
filter drier with desiccant made from 100% molecular sieve
grade XH-11. Filter drier must be replaced whenever the refrig­erant system is opened.

When removing a filter drier, use a tubing cutter to cut the drier
from the system. Do not unsweat a filter drier from the sys­tem. Heat from unsweating will release moisture and contami­nants from drier into system.

Field Refrigerant Access Ports — Field service

access to refrigerant pressures is through the access ports
located at the service valves (see Figs 27 and 29). These ports
are ¼-in SAE Flare couplings with Schrader check valves and
service caps. Use these ports to admit nitrogen to the field
tubing during brazing, to evacuate the tubing and evaporator
coil, to admit initial refrigerant charge into the low-side of the
system and when checking and adjusting the system refrigerant
charge. When service activities are completed, ensure the
service caps are in place and secure; check for leaks. If the
Schrader check valve must be removed and re-installed, tighten
to 23-34 N-cm (2-3 in-lbs).

Factory High-Flow Access Ports — There are two

additional access ports in the system - on the suction tube
between the compressor and the suction service valve and on
the liquid tube near the liquid service valve (see Figs 28 and

30). These are brass fittings with black plastic caps. The hose
connection fittings are standard ¼-in SAE Male Flare
couplings.

The brass fittings are two-piece High Flow valves, with a re­ceptacle base brazed to the tubing and an integral spring-closed
check valve core screwed into the base. (See Fig. 25) This
check valve is permanently assembled into this core body and
cannot be serviced separately; replace the entire core body if
necessary. Service tools are available from RCD that allow the
replacement of the check valve core without having to recover
the entire system refrigerant charge. Apply compressor refrig­erant oil to the check valve core's bottom o-ring. Install the fit­ting body with 1085 ±23 N-cm (96 ±-10 in-lbs) of torque; do
not overtighten.

Fig. 25 — CoreMax Access Port Assembly

27

Comfort Alert Diagnostic Module

The Comfort Alert Diagnostic Module (CADM) monitors and
analyzes data from the Copeland Scroll
sor and the thermostat demand. The CADM also provides a
3-minute anti-recycle time delay to compressor cycling.

The CADM detects causes for electrical and system related
failures without any sensors. Flashing LEDs communicate the
Alert codes to guide service technicians in accurately and
quickly troubleshooting the system and determining root cause
for the failure.

Inputs to the CADM include 24-vac power, thermostat Y1,
compressor contactor coil (common side) and compressor
power leads (from the compressor contactor).

Input Terminal Voltage

Control
Power

Control
Common

Cooling Y 24-V
Contactor

Coil
Line A T1 Line
Line B T2 Line
Line C T3 Line

Control of the compressor contactor coil is through a
normally-closed (power on the module) contact between
terminals P and C.

Communications of status and alert conditions is through three
LEDs located on the top edge of the module housing (see
Fig. 26): POWER (green), ALERT (yellow), and TRIP (red).

The POWER LED indicates the presence of control power to
the CADM.

®

three-phase compres-

R 24-V

C 24-V

P 24-V

POWER
(GRN)

ALERT
(YEL)

TRIP
(RED)

Fig. 26 — CADM Housing/LED Locations

The ALERT LED indicates an abnormal condition exists in the
system through a flash code. The ALERT LED will blink a
number of times consecutively, pause and the repeat the
process. The number of blinks, defined in Table 13, correlates
to a particular abnormal condition; troubleshooting tips are
provided for each Alert code. Reset of the ALERT may be
automatic or manual. If the fault condition causing the Alert is
self-corrected, the Alert code will be removed and the CADM
will automatically reset and allow the system to restart
normally. Manual reset requires that main power to the 38AU
unit be recycled after the cause for the Alert condition has been
detected and corrected.

The TRIP LED indicates either a time-delay period is currently
active (RED LED is blinking) or the module has locked out the
compressor (RED LED is on steady). A lockout condition will
occur when the CADM detects a thermostat demand at input Y
but there is no power at the compressor line terminals T1 or T2
or T3. This lockout can occur due to a safety switch (LPS or
HPS) opening and de-energizing the compressor contactor, the
compressor-motor internal overload opens, or other internal
power interruption has occurred. Reset of the TRIP LED
requires that unit main power be recycled after the loss of
power to the compressor condition has been detected and
corrected.

Simultaneous Blinking of YELLOW and RED LEDs indicates
control power input to the CADM is low. Check control circuit
transformer and wiring.

Troubleshooting the CADM Wiring – Flashing LEDs also
indicate wiring problems to the CADM. See Table 14 for
discussion of additional LED flash codes and troubleshooting
instructions.

28

Table 13 — LED Status Codes

Status LED Status LED Description Status LED Troubleshooting Information

Green “POWER” Module has power Supply voltage is present at module terminals
Red “TRIP”

LED On Solid

Red “TRIP” LED
Flashing

Module locks out compressor when compressor damaging ALERT code appears.
Lockout ALERT codes are noted in the Status LED Description.
During a compressor lock out, 24VAC power must be removed from module to manually reset.

Yellow “ALERT”
LED On Solid

Yellow “ALERT”
Flash Code 2

Yellow “ALERT”
Flash Code 3

Yellow “ALERT”
Flash Code 4

Yellow “ALERT”
Flash Code 5

Yellow “ALERT”
Flash Code 6

Yellow “ALERT”
Flash Code 7

Yellow “ALERT”
Flash Code 8

Yellow “ALERT”
Flash Code 9

Thermostat demand signal Y
is present, but the
compressor is not running.

The anti-short cycle timer (3 minutes), in module is preventing compressor
restart.

A short circuit or over current
condition exists on PROT
terminal.

System Pressure Trip
Discharge pressure out of
limits or compressor
overload (if no high pressure
switch in system)
LOCKOUT

Short Cycling
Compressor is running only
briefly LOCKOUT

Locked Rotor
LOCKOUT

Open Circuit 1. Condensing unit power disconnect is open

Missing Phase
LOCKOUT

Reverse Phase
LOCKOUT

Welded Contactor
Compressor always runs

Low Voltage
Control circuit < 18VAC

1. Compressor protector is open

2. Condensing unit power disconnect is open

3. Compressor circuit breaker or fuse(s) is open

4. Broken supply wires or connector is not
making contact

5. Compressor power wires not routed through
Comfort Alert

6. Compressor contactor has failed open

1. Compressor contactor coil shorted

2. Electrical load too high for PROT circuit
(maximum 1 Amp)

3. 24 V AC wired directly to PROT terminal

1. High head pressure

2. Condenser coil poor air circulation (dirty,
blocked, damaged)

3. Condenser fan is not running

4. If low pressure switch is open:

Refer to Code 3 for troubleshooting

1. If low pressure switch is open:
a. Low refrigerant charge
b. Evaporator blower is not running
c. Evaporator coil is frozen
d. Faulty metering device
e. Condenser coil is dirty
f. Liquid line restriction (filter drier blocked if

present)

2. If high pressure switch is open, go to Flash
Code 2 information

3. Intermittent thermostat demand signal

4. System or control board defective

1. Low line voltage to compressor

2. Excessive liquid refrigerant in compressor

3. Compressor bearings are seized

2. Compressor circuit breaker or fuses are open

3. Compressor contactor has failed open

4. High pressure switch is open and requires
manual reset

5. Broken supply wires or connector is not
making contact

6. Unusually long compressor protector reset
time due to extreme ambient temperature

7. Compressor windings are damaged

1. Compressor fuse is open on one phase

2. Broken wire or connector on one phase

3. Compressor motor winding is damaged

4. Utility supply has dropped one phase

1. Compressor running backward due to supply
phase reversal

1. Compressor contactor has failed closed

2. Thermostat demand signal not connected to
module

1. Control circuit transformer is overloaded

2. Low line voltage to compressor

29

Table 14 — CADM Troubleshooting

Miswired Module Indication Recommended Troubleshooting Action

Green LED is not on,
module does not power up

Green LED Intermittent,
module powers up only
when compressor runs

TRIP LED is on but system
and compressor check OK

TRIP LED and ALERT LED
flashing together

ALERT Flash Code 3
(Compressor Short Cycling)
displayed incorrectly

ALERT Flash Code 5 or 6
(Open Circuit, Missing Phase)
displayed incorrectly

Alert Flash Code *
(Welded Contactor)
displayed incorrectly

Determine if both R and C module terminals are
connected. Verify voltage in present at module’s R and C
terminals.
NOTE: The CADM requires a constant nominal 24VAC
power supply. The wiring to the module’s R and C
terminals must be directly from the control transformer.
The module cannot receive its power from another device
that will interrupt the 24VAC power supply. See Fig. 23
and (38AUZ Wiring Diagram) and Fig. 24 (38AUD Wiring
Diagram).

Determine if R and Y terminals are wired in reverse. Verify
module’s R and C terminals have a constant source. See
“NOTE” above for details on R and C wiring.

Verify Y terminal is wired properly per the 38AU wiring
diagram (see Figs. 23 and 24). Verify voltage at contactor
coil falls below 0.5VAC when off. Verify 24VAQC is present
across Y and C when thermostat demand signal is
present. If not, R and C are reverse wired.

Verify R and C terminals are supplied with 19-28VAC.

Verify Y terminal is connected to 24VAC at contactor coil.
Verify voltage at contactor coil falls below 0.5VAC when
off.

Check that compressor T1 and T3 wires are through
module’s current sensing holes. Verify Y terminal is
connected to 24VAC at contactor coil. Verify voltage at
contactor coil falls below 0.5VAC when off.

Determine if module’s Y terminal is connected. Verify Y
terminal is connected to 24VAC at contactor coil. Verify
24VAC is present across Y and C when thermostat
demand signal is present. If not, R and C are reverse
wired. Verify voltage at contactor coil falls below 0.5VAC
when off.

Crankcase Heater — The heater prevents refrigerant

migration and compressor oil dilution during shutdown when­ever compressor is not operating. The heater is wired to cycle
with the compressor; the heater is off when compressor is run­ning, and on when compressor is off.

The crankcase heater will operate as long as the power circuit
is energized.

Compressor Protection

COMPRESSOR OVERTEMPERATURE PROTECTION
(IP) — A thermostat installed on the compressor motor wind­ing reacts to excessively high winding temperatures and shuts
off the compressor.

CRANKCASE HEATER — The heater minimizes absorp­tion of liquid refrigerant by oil in the crankcase during brief or
extended shutdown periods. The main disconnect must be on
to energize the crankcase heater.

IMPORTANT: Never open any switch or disconnect that
energizes the crankcase heater unless unit is being serviced
or is to be shut down for a prolonged period. After a pro­longed shutdown on a service job, energize the crankcase
heater for 24 hours before starting the compressor.

ADVANCED SCROLL TEMPERATURE PROTECTION
(ASTP) — See “Advanced Scroll Temperature Protection
(ASTP)” on page 21.

Low-Pressure Switch — The 38AU low-pressure

switch is stem-mounted on the suction line. Switches are all
fixed, non-adjustable type.

High-Pressure Switch — The 38AU high-pressure

switch is stem-mounted on the discharge line. The switch is a
fixed, non-adjustable type.

Outdoor Fans — Each fan is supported by a formed-wire

mount bolted to the fan deck and covered with a wire guard.
Fan motors have permanently lubricated bearings.

Lubrication

FAN MOTORS have sealed bearings. No provisions are made
for lubrication.

COMPRESSOR has its own oil supply. Loss of oil due to a
leak in the system should be the only reason for adding oil after
the system has been in operation.

30

Condenser Fans

Service
Valves

HPS

LPS

High Flow
Access Port

32LT Sensor
Typical Location

Outdoor Coil

Fig. 27 — Typical Exterior, Single-Circuit Unit (38AUZ*08 shown)

Fig. 28 — Typical Interior, Single-Circuit Unit (38AUZ*08 shown)

31

Condenser Fans

HPS

LPS

High Flow
Access Ports

Motormaster
Sensor Location

Outdoor Coil

Service
Valves

Fig. 29 — Typical Exterior, Two-Circuit Unit (38AUD*14 shown)

Fig. 30 — Typical Interior, Two-Circuit Unit (38AUD*14 shown)

32

NOVATION™ Coil Cleaning and Maintenance —

To clean the NOVATION condenser coil, chemicals are NOT
to be used; only water is approved as the cleaning solution.
Only clean potable water is authorized for cleaning
NOVATION condensers.

Clean the coil as follows:

1. Turn off unit power.

2. Remove screws holding rear corner posts and top cover
in place. Pivot top cover up 305 to 457 mm (12 to 18 in.)
and support with a rigid support. See Fig. 31

Fig. 31 — Pivot and Support Top Cover

3. Carefully remove any foreign objects or debris attached
to the coil face or trapped within the mounting frame and
brackets.

4. Using a high pressure water sprayer, purge any soap or
industrial cleaners from hose and/or dilution tank prior to
wetting the coil.Clean condenser face by spraying the coil
core steadily and uniformly from top to bottom, directing
the spray straight into or toward the coil face. Do not
exceed 900 psig or a 45 degree angle; nozzle must be at
least 30 cm (12 in.) from the coil face. Reduce pressure
and use caution to prevent damage to air centers (fins).
Do not fracture the braze between air centers and
refrigerant tubes. Allow water to drain from the coil core
and check for refrigerant leaks prior to start−up.

5. Replace top cover and rear corner posts.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in damage to
equipment.

Chemical cleaning should NOT be used on the aluminum
microchannel (NOVATION) condenser. Damage to the coil
may occur. Only approved cleaning is recommended.

Repairing NOVATION Condenser Tube Leaks

RCD offers service repair kit Part Number 50TJ660007 for
repairing tube leaks in the NOVATION coil crosstubes. This kit
includes approved braze materials (aluminum fluxcore braze
rods), a heat shield, a stainless steel brush, replacement fin
segments, adhesive for replacing fin segments, and instructions
specific to the NOVATION aluminum coil. See EPIC for
instruction sheet 99TA526379.

The repair procedure requires the use of MAPP gas and torch
(must be supplied by servicer) instead of conventional
oxyacetylene fuel and torch. While the flame temperature for
MAPP is lower than that of oxyacetylene (and thus provides
more flexibility when working on aluminum), the flame
temperature is still higher than the melting temperature of
aluminum, so user caution is required. Follow instructions
carefully. Use the heat shield.

Replacing NOVATION Condenser Coil

The service replacement coil is preformed and is equipped with
transition joints with copper stub tubes. When brazing the
connection joints to the unit tubing, use a wet cloth around the
aluminum tube at the transition joint. Avoid applying torch
flame directly onto the aluminum tubing.

Service Parts

Listings of service parts for all units are available from the Re­placement Components Division’s Electronic Parts Informa­tion Catalog (EPIC). EPIC is available at Totaline stores, dis­tributor and service office parts departments and on-line at
HVACPartners.com.

When entering EPIC, the full unit model number is required.
The model number includes the Design Revision reference val­ue (see Fig. 2, Position 13). The unit model number is available
from the unit’s information data plate. (Do not use the “catalog
number” when using EPIC. The “catalog number” suppresses
the Design Revision value; failure to include Design Revision
value may cause an incorrect unit parts list to be displayed.)
When using EPIC, enter first four digits of the model number
only. Find appropriate model from sales packages listed. Be
sure to choose correct voltage and Design Revision.

EPIC is a product of RCD. To comment of the EPIC program,
use the “Comment” button inside the EPIC program.

FASTENER TORQUE VALUES

Table 15 — Torque Values

Compressor mounting bolts 734–847 N–cm (65–75 in–lbs)
Condenser fan motor mounting bolts 226 ±23 N–cm (20 ±2 in–lbs)
Condenser fan hub setscrew 949 ±136 N–cm (84 ±2 in–lbs)
High-flow service port 1085 ±23 N–cm (96 ±10 in–lbs)
Schrader-type service check valve 23–34 N–cm (2–3 in–lbs)

33

TROUBLESHOOTING

PROBLEM SOLUTION

COMPRESSOR DOES NOT RUN

Contactor Open

1. Power off. 1. Restore power.

2. Fuses blown in field power circuit. 2. After finding cause and correcting, replace with correct size fuse.

3. No control power. 3. Check control transformer primary connections and circuit breaker.

4. Thermostat circuit open. 4. Check thermostat setting.

5. Safety device lockout circuit active. 5. Reset lockout circuit.

6. Low-pressure switch open. 6. Check for refrigerant undercharge, obstruction of indoor airflow.

7. High-pressure switch open. 7. Check for refrigerant overcharge, obstruction of outdoor airflow, air

8. Compressor overtemperature switch open. 8. Check for open condition. Allow for reset. Replace if defective.

9. Loose electrical connections. 9. Tighten all connections.

10. Compressor stuck. 10. See compressor service literature.
Contactor Closed

1. Compressor leads loose. 1. Check connections.

2. Motor windings open. 2. See compressor service literature.

3. Single phasing. 3. Check for blown fuse. Check for loose connection at compressor

COMPRESSOR STOPS ON HIGH-PRESSURE SWITCH

Outdoor Fan On

1. High-pressure switch faulty. 1. Replace switch.

2. Reversed fan rotation. 2. Confirm rotation, correct if necessary.

3. Airflow restricted. 3. Remove obstruction.

4. Air recirculating. 4. Clear airflow area.

5. Noncondensables in system. 5. Recover refrigerant and recharge as required.

6. Refrigerant overcharge. 6. Recover refrigerant as required.

7. Line voltage incorrect. 7. Consult power company.

8. Refrigerant system restrictions. 8. Check or replace filter drier, expansion valve, etc.
Outdoor Fan Off

1. Fan slips on shaft. 1. Tighten fan hub setscrews.

2. Motor not running. 2. Check power and capacitor.

3. Motor bearings stuck. 3. Replace bearings.

4. Motor overload open. 4. Check overload rating. Check for fan blade obstruction.

5. Motor burned out. 5. Replace motor.

COMPRESSOR CYCLES ON LOW-PRESSURE SWITCH

Indoor-Air Fan Running

1. Liquid line solenoid valve(s) fails to open. 1. Check liquid line solenoid valve(s) for proper operation. Replace if

2. Filter drier plugged. 2. Replace filter drier.

3. Expansion valve power head defective. 3. Replace power head.

4. Low refrigerant charge. 4. Add charge. Check low-pressure switch setting.
Airflow Restricted

1. Coil iced up. 1. Check refrigerant charge.

2. Coil dirty. 2. Clean coil fins.

3. Air filters dirty. 3. Clean or replace filters.

4. Dampers closed. 4. Check damper operation and position.
I

ndoor-Air Fan Stopped

1. Electrical connections loose. 1. Tighten all connections.

2. Fan relay defective. 2. Replace relay.

3. Motor overload open. 3. Power supply.

4. Motor defective. 4. Replace motor.

5. Fan belt broken or slipping. 5. Replace or tighten belt.

Make sure liquid line solenoid valve(s) is open.

in system. Be sure outdoor fans are operating correctly.

terminal.

necessary.

34

TROUBLESHOOTING (cont)

PROBLEM SOLUTION

COMPRESSOR RUNNING BUT COOLING INSUFFICIENT

Suction Pressure Low

1. Refrigerant charge low. 1. Add refrigerant.

2. Head pressure low. 2. Check refrigerant charge. Check outdoor-air fan thermostat settings.

3. Air filters dirty. 3. Clean or replace filters.

4. Expansion valve power head defective. 4. Replace power head.

5. Indoor coil partially iced. 5. Check low-pressure setting.

6. Indoor airflow restricted. 6. Remove obstruction.
Suction Pressure High

1. Unloaders not functioning 1. Check unloader adjustments. Check unloader setting.

2. Heat load excessive. 2. Check for open doors or windows in vicinity of fan coil.

UNIT OPERATES TOO LONG OR CONTINUOUSLY

1. Low refrigerant charge. 1. Add refrigerant.

2. Control contacts fused. 2. Replace control.

3. Air in system. 3. Purge and evacuate system.

4. Partially plugged expansion valve or filter drier. 4. Clean or replace.

SYSTEM IS NOISY

1. Piping vibration. 1. Support piping as required.

2. Compressor noisy. 2. Replace compressor if bearings are worn.

COMPRESSOR LOSES OIL

1. Leak in system. 1. Repair leak.

2. Crankcase heaters not energized during shutdown. 2. Check wiring and relays. Check heater and replace if defective.

3. Improper interconnecting piping design. 3. Check piping for oil return. Replace if necessary.

FROSTED SUCTION LINE

Expansion valve admitting excess refrigerant. Adjust expansion valve.

HOT LIQUID LINE

1. Shortage of refrigerant due to leak. 1. Repair leak and recharge.

2. Expansion valve opens too wide. 2. Adjust expansion valve.

FROSTED LIQUID LINE

1. Restricted filter drier. 1. Remove restriction or replace.

2. Liquid line solenoid valve partially closed. 2. Replace valve.

35

APPENDIX A

AIR CONDITIONER AND HEAT PUMP WITH
PURON

•Puron® (R-410A) refrigerant operates at 50 percent to

•Puron

• Recovery cylinder service pressure rating must be 400

•Puron

• Manifold sets should be 700 psig high side and 180 psig

• Use hoses with 700 psig service pressure rating.

• Leak detectors should be designed to detect HFC

•Puron

• Vacuum pumps will not remove moisture from oil.

• Use only factory specified liquid-line filter driers with

®

— QUICK REFERENCE GUIDE

70 percent higher pressures than R-22. Be sure that
servicing equipment and replacement components are
designed to operate with Puron

®

refrigerant cylinders are rose colored.

®

.

psig, DOT 4BA400 or DOT BW400.

®

systems should be charged with liquid
refrigerant. Use a commercial type metering device in
the manifold hose when charging into suction line with
compressor operating.

low side with 550 psig low-side retard.

refirgerant.

®

, as with other HFCs, is only compatible with
POE oils.

rated working pressures greater than 600 psig.

• Do not install a suction-line filter drier in liquid-line.

• POE oils absorb moisture rapidly. Do not expose oil to
atmosphere.

• POE oils may cause damage to certain plastics and
roofing materials.

• Wrap all filter driers and service valves with wet cloth
when brazing.

• A factory approved, liquid-line filter drier is required on
every unit.

• Do not use an R-22 TXV.

• If indoor unit is equipped with a TXV, it must be
changed to a Puron

®

TXV.

• Never open system to atmosphere while it is under a
vacuum.

• When system must be opened for service, recover
refrigerant, break vacuum with dry nitrogen before
opening system.

• Always replace filter drier after opening system for
service.

• Do not vent Puron

®

into the atmosphere.

• Do not use capillary tube coils.

• Observe all warnings, cautions, and bold text.

•All Puron

• Do not leave Puron

®

heat pumps must have indoor TXV.

®

suction line driers in place for

more than 72 hours.

APPENDIX B

WIRING DIAGRAM LIST

38AU

Size Electrical Characteristics Diagram Number
Z*07 208/230-3-60 38AU500432
Z*08 208/230-3-60 38AU500432
D*12 208/230-3-60 38AU500563
D*14 208/230-3-60 38AU500563

36

APPENDIX C

508 mm

(20 in)

Sensor

MOTORMASTER SENSOR LOCATIONS

Sensor

254 mm

(10 in)

Fig. 32 — 38AUZ*07-08 Motormaster Sensor Locations Fig. 33 — 38AUD*12-14 Motormaster Sensor Locations

37

Copyright 2009 Carrier Corp • 7310 W. Morris St. • Indianapolis, IN 46231 Printed in U.S.A. Edition Date:12/09 Catalog No: 38AU-C01SI

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations. Replaces: New

38

III. START UP

START-UP CHECKLIST

I. PRELIMINARY INFORMATION

OUTDOOR: MODEL NO. SERIAL NO.
INDOOR: AIR HANDLER MANUFACTURER

MODEL NO. SERIAL NO.

ADDITIONAL ACCESSORIES

II. PRE-START-UP

OUTDOOR UNIT

IS THERE ANY SHIPPING DAMAGE?
IF SO, WHERE:

WILL THIS DAMAGE PREVENT UNIT START-UP? (Y/N)
CHECK POWER SUPPLY. DOES IT AGREE WITH UNIT? (Y/N)
HAS THE GROUND WIRE BEEN CONNECTED? (Y/N)
HAS THE CIRCUIT PROTECTION BEEN SIZED AND INSTALLED PROPERLY? (Y/N)
ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY? (Y/N)

CONTROLS

ARE THERMOSTAT AND INDOOR FAN CONTROL WIRING CONNECTIONS MADE AND CHECKED?

(Y/N)
ARE ALL WIRING TERMINALS (including main power supply) TIGHT? (Y/N)
HAS CRANKCASE HEATER BEEN ENERGIZED FOR 24 HOURS? (Y/N)

(Y/N)

INDOOR UNIT

HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE? (Y/N)
ARE PROPER AIR FILTERS IN PLACE? (Y/N)
HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT? (Y/N)
DO THE FAN BELTS HAVE PROPER TENSION? (Y/N)
HAS CORRECT FAN ROTATION BEEN CONFIRMED? (Y/N)

PIPING

ARE LIQUID LINE SOLENOID VALVES LOCATED AT THE INDOOR COILS AS REQUIRED? (Y/N)
HAVE LEAK CHECKS BEEN MADE AT COMPRESSOR, OUTDOOR AND INDOOR COILS,

TXVs (Thermostatic Expansion Valves), SOLENOID VALVES, FILTER DRIERS, AND FUSIBLE PLUGS
WITH A LEAK DETECTOR? (Y/N)

LOCATE, REPAIR, AND REPORT ANY LEAKS.
HAVE LIQUID LINE SERVICE VALVES BEEN OPENED? (Y/N)
HAVE SUCTION SERVICE VALVES BEEN OPENED? (Y/N)

CHECK VOLTAGE IMBALANCE

LINE-TO-LINE VOLTS: AB
(AB + AC + BC)/3 = AVERAGE VOLTAGE =
MAXIMUM DEVIATION FROM AVERAGE VOLTAGE = V
VOLTAGE IMBALANCE = 100 X (MAX DEVIATION)/(AVERAGE VOLTAGE) =
IF OVER 2% VOLTAGE IMBALANCE, DO NOT ATTEMPT TO START SYSTEM!

CALL LOCAL POWER COMPANY FOR ASSISTANCE.

VAC VBCV

V

CL-1

CHECK INDOOR UNIT FAN SPEED AND RECORD.
CHECK OUTDOOR UNIT FAN SPEED AND RECORD.
AFTER AT LEAST 10 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:

Circuit A Circuit B
SUCTION PRESSURE
SUCTION LINE TEMP
LIQUID PRESSURE
LIQUID LINE TEMP
ENTERING OUTDOOR UNIT AIR TEMP
LEAVING OUTDOOR UNIT AIR TEMP
INDOOR UNIT ENTERING-AIR DB (dry bulb) TEMP
INDOOR UNIT ENTERING-AIR WB (wet bulb) TEMP
INDOOR UNIT LEAVING-AIR DB TEMP
INDOOR UNIT LEAVING-AIR WB TEMP

COMPRESSOR AMPS (L1/L2/L3) (A/B) / / / /

NOTES:

Copyright 2009 Carrier Corp • 7310 W. Morris St. • Indianapolis, IN 46231 Printed in U.S.A. Edition Date: 12/09 Catalog No: 38AU-C01SI

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations. Pg CL-2 Replaces: New

CUT ALONG DOTTED LINE CUT ALONG DOTTED LINE

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - -