Carrier 38AK024-044 User Manual

38AK024-044

HEATING A COOLING

Air-Cooled Condensing Units

Installation, Start-Up and Service Instructions

50- and 60-Hertz Air-Cooled Packages

CONTENTS

Page

SAFETY CONSIDERATIONS

BEFORE INSTALLATION

Rigging ...........................................................................l

Placing Unit .................................................................. 3

Mounting Unit
Compressor Mounting

INSTALLATION

Refrigerant Piping Connections ..................................3

Single Pumpout Control

Filter Drier and Moisture Indicator...............................3

Receiver .........................................................................3

Piping Procedure ...........................................................3

Power Supply .................................................................5

Power Wiring..................................................................5

START-UP ................................................................11-16

Initial Check...................................................................11

Leak Test and Dehydration
Preliminary Charge

Start Unit .......................................................................11

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1-3

3

3-10

3

11
11

1

3

Charge System .........................................................11

Operation ..................................................................11

Timer Functions ........................................................16

Sequence of Operation.............................................16

Complete Unit Stoppage
SERVICE

Access for Servicing ................................................17

Fan Adjustment ........................................................18

Oil Charge

Liquid Shutoff/Charging Valve

Capacity Control .......................................................18

Oil Pressure Safety Switch (OPS)
Compressor Protection

High-Pressure Switch ..............................................19

Low-Pressure Switch ...............................................19

Winter Start Control

Head Pressure Control

TROUBLESHOOTING .20

..............................................................

.................................................................

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...............................

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17-19

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Page

16

18
18

19
19

19

19

SAFETY CONSIDERATIONS

Installing, starting up and servicing air conditioning
equipment can be hazardous due to system pressures,
electrical components and equipment location (roofs, ele
vated structures, etc.)

Only trained, qualified installers and service mechanics
should install, start-up and service this equipment (Fig. 1).

Untrained personnel can perform basic maintenance
functions such as cleaning coils. All other operations should
be performed by trained service personnel.

When working on the equipment, observe precautions in
the literature and on tags, stickers and labels attached to the
equipment.

• Follow all safety codes.

• Wear safety glasses and work gloves.

• Keep quenching cloth and fire extinguisher nearby when

brazing.

• Use care in handling, rigging and setting bulky equipment.

• See Table 1 for Physical Data.

ELECTRIC SHOCK HAZARD

Cm

tr

Open all remote disconnects before
servicing this equipment.

BEFORE INSTALLATION

Rigging — Preferred method is with spreader bars

from above the unit. Use 2-in. (50 mm) OD pipe or
hooks in lifting holes. Rig with 4 cables and spreader
bars. All panels must be in place when rigging. See
rigging label on unit for details concerning shipping
weights, distance between lifting holes, center of
gravity and spreader bar dimensions. See Fig. 2.

If overhead rigging is not possible, place chiller on

skid or pad for rolling or dragging. When rolling, use

minimum 3 rollers. When dragging, pull the pad. Do

not apply force to the unit When in final position, raise

from above to lift unit off pad.

A CAUTION

All panels must be in place when rigging. Do not fork
units if no skid is supplied. If unit has skid, truck from
sides only.

Book 1
Tab I 3a

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obiigations.

PC111

Catalog No 563-915

Printed in U S A Form 38AK-1SIM

Pgi

11-89

Replaces: New

3/4-IN (19mm) NOTCHES
IN END OR SPREADERS

Fig. 1 - Model 38AK (024 shown)

Fig. 2 — Rigging with Spreader Bars (Field Supplied)

Table 1A — Physical Data — 60 Hertz

UNIT 38AK

COMPRESSOR Reciprocating Semi-Hermetic

No. ...Type 1 06E4250 1 06E9265

No. Cyls (ea) ...Speed, Rpm (r/s) 4 1750(29)
Capacity Steps
Oil Charge*, Pt (L) 14(66)

Oil Pressure Switch Setting (psid)

Crankcase Heater (watts)
Protection See Note
Capacity Control
No. 1

Load
Unload

No. 2

Load
Unload

REFRIGERANT CHG, R-22

Approximate lb (kg)

CONDENSER FANS, Type Propeller Type, Direct Driven

No. ...Diameter, in. (mm)

Total Airflow, Cfm (L/s) 10,600 (5,000) 15,700 (7,400) 23,700(11,200)
Speed, Rpm (r/s) 1140(19)

CONDENSER COIL, Type Horizontal, Plate Fin

Rows...Fins/in. (Fin Spacing mm)
Total Face Area, sq ft (m‘)

024 028 034

1 06E9275

2

6 1750(29)

3

19(9)

180

Suction Pressure Unloader(s)

Unloader Settings (psig)

76
58

—

—

28 (12 7) 305(138)

3 ... 17 (1 49) 2 19(134)

235(218) 39 2(364) 584(543)

76
58

Unloader Settings (psig)

78
60

2 30(762)

76 76
58 58

78 78
60

435(19.7) 65(295)

3 ...30 (762)

3 17(149)

Table IB — Physical Data — 50 Hertz

UNIT 38AK 024
COMPRESSOR

No.... Type 1 06E4250

No. Cyls (ea)... Speed, Rpm (r/s)
Capacity Steps
Oil Charge*, Pt (L)

Oil Pressure Switch Setting (psid)
Crankcase Heater (watts)
Protection
Capacity Control
No. 1

Load
Unload

No. 2

Load
Unload

REFRIGERANT CHG., R-22

Approximate lb (kg)

CONDENSER FANS, Type Propeller Type, Direct Driven

No.... Diameter, in. (mm)

Total Airflow, dm (L/s)
Speed, Rpm (r/s)

CONDENSER COIL, Type Horizontal, Plate Fin

Rows ... Fins/in. (Fin Spacing mm)
Total Face Area, sq ft (m‘)

*See Service, Oil Charge, for Carrier-approved oil

Paid - pounds per sq in differential

4 1450(24 2)

2

14(66)

76
58

—

—

28(12 7)

10,600 (5,000)

3... 17 (149)
235(218) 39.2(364)

NOTE: Circuit breaker in main power circuit and discharge gas thermostat in control circuit

028 034 044

Reciprocating, Semi-Hermetic

1 06E9265 1 06E9275 1 06E9299

Suction Pressure Unloader(s)

Unloader Settings (psig)
76
58

Unloader Settings (psig)
78
60

305(13.8)

2 30 (762) 3... 30 (762)

15,700 (7,400) 23,700 (11,200)

950 (15 8)

2 19(134)

c

180

See Note

6 1450(24 2)

3

19(9)

76 76
58 58

78
60

435(197) 65(295)

3. 17(149)

2

044

1 06E9299

60

78
60

584(543)

Placing Unit — There must be 4 ft (1220 mm) for service
and for unrestricted airflow on all sides of unit, and a
minimum of 8 ft (2440 mm) clear air space above unit. For
multiple units, allow 8 ft separation between units for
airflow and service.

Mounting Unit — When unit is in proper location, use of

mounting holes in base rails is recommended for securing
unit to supporting structure, or for mounting unit on
vibration isolators if required. Fasteners for mounting unit
are field supplied. Be sure to mount unit level to ensure
proper oil return to compressors.

Compressor Mounting — As shipped, compressor is
held down by 4 bolts. After unit is installed loosen each bolt
until the snubber washer can be moved with finger pressure.
See Fig. 3.

Single Pumpout Control — All units are factory wired
to operate on single pumpout control. A factory-supplied
liquid line solenoid valve must be installed in the liquid line
ahead of the indoor coil. See Fig. 5. Wires from solenoid
valve must be in conduit, and a ground wire must be
provided to comply with codes.

A WARNING

Failure to properly install liquid line solenoid at the
indoor unit as described, without Carrier author
ization, may VOID warranty.

If unit is used with a chiller, wiring modifications may be

required.

Filter Drier And Moisture Indicator — Every unit
should have a filter drier and a sight glass (moisture

indicator) field installed. Select the filter drier for maximum
unit Capacity and minimum pressure drop. Figure 5 shows
recommended locations of filter drier(s) and sight glass.
Complete the refrigerant piping from the evaporator to the
condenser before opening the liquid and suction lines at the
condensing unit. One filter drier may be installed at location
A in Fig. 5, or 2 filter driers may be installed at locations B.

INSTALLATION

Refrigerant Piping Connections — Line sizes depend

on length of piping required between condensing unit and
evaporator. See Table 2. It is important to consider liquid
lift and compressor oil return. Refer to Part 3 of Carrier
System Design Manual for line sizing information, and
Fig. 4 for recommended piping details.

NOTES:
1 Suction line is connected to coil on same side as the entering air.
2 For coils having only one section, use upper section piping; for coiis

having 2 sections, use upper and middle section piping
3 Lower section is first on and last off.
4 For more complete piping information, refer to Carrier System

Design Manual, Part 3

Fig. 4 — Suction Line Piping to Unit

with 3 Section Coil Split

FACTORY SUPPLIED
SOLENOID VALVE

FIELD SUPPLIED

CAPACITY CONTROL

Fig. 5 — Liquid Line Solenoid Valve,

Filter Drier(s) and Sight Glass Locations

Receiver — No receiver is provided with the unit; it is

recommended that one not be used.

Piping Procedure — Do not remove run-around pipe

from suction and liquid line stubs until piping connections are

ready to be made. Pass nitrogen or other inert gas through

piping while brazing, to prevent formation of copper oxide.

Install field-supplied thermostatic expansion valve in

liquid line ahead of each evaporator section. For 2-step
cooling, the fleld-supplkd solenoid used must be wired to be

opened by control from a 2-step thermostat

For example: 2 solenoids may be used with 3 TXVs —one

of the solenoids serving a liquid line feeding 2 of the TXVs.

Table 2 — Refrigerant Piping Sizes

SINGLE SUCTION RISERS

MODEL

38AK

024 5/8 1-5/8
028 7/8 1-5/8
034
044

L-Liquid Line S-Suction Line

* IMPORTANT — Requires a double suction riser, see below:

NOTE: Liquid and suction iine sizes are OD (in)

(a) - SUCTION RISER WITHOUT TRAP
(b) - SUCTION RISER WITH TRAP

(^- SUCTION LINE TO CONDENSING UNIT

7/8
7/8

16-25

L

S L S

2-1 /8
2-1/8 7/8 2-1/8

LENGTH OF INTERCONNECTING PIPING (FT)
26-50

7/8 1-5/8
7/8
7/8

2-1 /8 7/8
2-1/8 7/8

DOUBLE SUCTION RISERS

51-75

L

7/8

1-1/8

UNIT 38AK

024 86
028
034 67
044 76

76-100

S

2-1/8 7/8
2-1/8 7/8
2-1/8

*

L

1-1 /8

1-1/8

2-1/8
2-1/8

MAXIMUM LIQUID LIFT

60 Hz 50 Hz

Ft

M

26 72

76

23
20
23

S

*
*

101-200

L S

7/8 2-1/8

7/8 2-1/8
1-1/8
1-1/8

Ft

21
66 20
60

18

66 20

*
*

M

MODEL

38AK

034
044

NOTE: A, B, C dimensions relate to reference diagram

2-1/8

51-75 76-100

A

B C

1-5/8

SUCTION PIPING AT EVAPORATOR AND TXV BULB LOCATION (See Fig. 5)

The purpose of these recommendations is to achieve good
mixing of the refrigerant leaving the evaporator suction
header for proper sensing by the TXV bulb.

1. A minimum of two 90° elbows must be installed
upstream of the expansion valve bulb location.

2. The TXV sensing bulb should be located on a vertical
riser where possible. If a horizontal location is neces
sary, secure the bulb at approximately the 4 o’clock
position.

3. Size the suction line from the evaporator through the
riser for high velocity. Enter the suction pipe sizing charts
in the Carrier System Design Manual at design tons and
equivalent length (for 2 degree F loss). If reading falls
between 2 sizes on chart, choose the smaller pipe size.

LENGTH OF INTERCONNECTING PIPING (FT)

A B C A

2-5/8

1-5/8
1-5/8

2-1/8
2-1/8

2-5/8
2-5/8

1-5/8
1-5/8

Suction piping for the high velocity section should be
selected for about 0.5 degree F friction loss. If a 2 degree
F loss is allowed for the entire suction line, 1.5 degree F
is left for the balance of the suction line and it should be
sized on that basis. Check that the high-velocity sizing is

adequate for oil return up the riser.

If an oil return connection at the bottom of this
suction header is supplied with an evaporator, this
connection must be teed-in ahead of first mixing elbow.

When the compressor is below the evaporator, the riser
at the evaporator does not have to extend as high as the

top level. After a 15-diameter riser has been provided,

the suction line may elbow down immediately.

SAFETY RELIEF — A fusible plug is located on unit
liquid line before the liquid valve.

101-200

B

2-1/8
2-1/8

C

2-5/8
2-5/8

Power Supply — Electrical characteristics of available

power supply must agree with unit nameplate rating. Supply
voltage must be within limits shown in Table 3.

IMPORTANT: Operating unit on improper supply
voltage, or with excessive phase imbalance, constitutes
abuse and may affect Carrier warranty. See Unbal
anced 3-Phase Supply Voltage, page 6.

Power Wiring — All power wiring must comply with
applicable local and national codes. Install field-supplied
branch circuit fused disconnect(s) per NEC (National Electri
cal Code) of a type that can be locked OFF or OPEN.
Disconnect(s) must be within sight from and readily acces
sible from unit in compliance with NEC Article 440-14.

Table 3 — Electrical Data

60 HERTZ

MODEL

OfiAtr

024

028

034

044

500
200
600
100

500
200
600
100

500
200
600
100

500
200
600

100

Volts

3 Ph, 60 Hz

208/230

380 342 418 51 1 80 194.9 346 191 3.9
460 414 508
575

208/230

380
460
575 518 632

208/230

380
460
575 518

230
380
460
575

SuDolied*

Min. Max. (Fuse)

187

518 632
187 254

342
414

187
342
414

187 254
342
414
518

UNIT COMPRESSOR

MCA

254 92.1 150 348.6

46.9

42.9 70

124.6 200
418 64.7 110
508 60 7 100 226.1

52.5 80

254

145 5 250
418 72.5 125
508 687 110
632

418
508 91 0 150
632 81.5 125 282.8

54.9 90

2030 350

111 1

50 HERTZ

MODEL

38AK

024

034

044 300

800 230
300 346
900

800

028 300 346

900 400

800 230

300

900
800 230
900

Volts

3 Ph, 50 Hz

400
230

346
400

346
400

Supplied*

Min. Max.

198 254
311
342

198 254 109 175 348.4 76.9 342
311
342

198 254 1202
311
342

198 254
311
342

UNIT

MCA

380 50.5 80
400 49.3 80 1740 347 173 1.0

380 64.9 100
400 605 100 226.0 436 223 30

88.1 125

380 76.1 125
400 68.5

1506 250
380 112.6 175
400 90.8 150 351 0

GENERAL WIRING NOTES

1. A crankcase heater is wired in the control circuit so it is
always operable as long as power supply disconnect is
on, even if any safety device is open or unit stop-start
switch is off. It is protected by a 5-amp circuit breaker in
control power.

2. The power circuit field supply disconnect should never be

open except when unit is being serviced or is to be down for a

prolonged period When operation is resumed crankcase

heater should be energtedfor 24 hours before start-up. If unit
is to be shut down for a prolonged period it is recommended
that the suction arid discharge valves be closed to prevent an
excessive accumulation of refrigerant in the compressor oil

3. Power entry is at one end only.

MOCP

ICF RLA LRA FLA (ea)

68

80 1748

175

MOCP
(Fuse)

123.4

452.2 89.8 446 6.2

250.9 45.5 247 3.9

167.4 36.5 164 3.4

512.2 106.5 506 6.2

283.9 52.6 280

256.1 50 253 3.1

179.4 38.5 176 3.4

702.4
3898 79.5 382 39
351 2 65.4 345 3.1

ICF RLA LRA FLA (ea)

256.4 60.3
2044

34 7

28.9 120 3.4

43.6 223 31

147 5 690

57.1 276 3.4 3

COMPRESSOR

333 200

263.4 44.9

200
110

372.4
2984
2560 50.0 253 3.0

5578 105.1

408.8 79.5

859 366
539 294

65.4

FAN MOTORS!

345

3.6

173 1 8

3.9

62 3

FAN MOTORS!

250

259

545
400

345 30

6.4 2
44 2

64 2

4.4 2

6.4

4.4 2

6.4 3

4.4

Qty

2
2
2
2

2
2
2
2

2
2
2
2

3
3

Qty

2

2
2

2

3
3

FLA — Full Load Amps
ICF — Maximum Instantaneous Current Flow during starting (the

LRA — Locked Rotor Amps

MCA — Minimum Circuit Amps (complies with National Electrical

MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps

* Units are suitable for use on electrical systems where voltage

supplied to unit terminals is not below or above listed minimum and
maximum limits

t All fans are protected by a single circuit breaker.

point in the starting sequence where the sum of the LRAfor
the starting compressor, plus the total RLA for all running
compressors, plus the total FLA for all running fan motors
is maximum).

Code [NEC], Section 430-24)

4. Maximum field wire sizes allowed by lugs on terminal
block are:
350 MCM for models 38AK028 (208/230-3-60),
38AK034 (208/230-3-60, 230-3-50), and
38AK044 (208/230-3-60, 230-3-50)
2/0 AWG for all other models.

5. Terminals for field power supply are suitable for
copper, copper-clad aluminum or aluminum conduc
tors. Insulation must be rated 167 F (75 C) minimum.

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 % voltage imbalance:

% Voltage Imbalance

= 100 X

max voltage deviation from average voltage

average voltage

I ^

CONDENSER FANS — The fans must rotate counter
clockwise when viewed from above. If necessary, correct
direction of fan rotation by interchanging any 2 power
input wires at disconnect switch. Affix crankcase heater
decal (located in installer’s packet) to unit disconnect switch.

FIELD CONNECTIONS

1. Main Power — Bring wires from the fused disconnect
switch through hole in bottom rail of unit to control

box (Fig. 6, 7, 8) and connect terminals 1111, [12

on line side of terminal block TBl (see Fig. 9).

13
To comply with NEC Article 440-14, the disconnect
must be located within sight from and readily acces
sible from unit.

■ 2. 24-v Control Power — Units have single point power
connections. Control circuit is directly connected inter
nally to unit. Maximum 24-v control circuit is 3 amps.

NOTE: For wire runs up to 50 ft. use no. 18 AWG
insulated wire (35 C min.). For 50 to 75 ft., use no. 16
AWG insulated wire (35 C min.). For over 75 ft. use 14
AWG insulated wire (35 C min.).

3. Control Circuit Interlock — An airflow switch may be
installed in the indoor air handler to prevent unit from

running when indoor air is not flowing. This switch (no.
HR81JE001) is available from Service Parts Center, or
equivalent can be field supplied. This should be electri

cally interlocked in the control circuit, between term
inals I 1 I and I 6 I (for flow switch) on TB2. See Fig.
9 for field wiring. This is in the 115-v circuit. Wires must

be run in conduit with ground wire.

4. Transformer Connections — See unit wiring label dia

gram, notes 1 and 2, located behind compressor com
partment end access door.

Example: Supply voltage is 240-3-60.

AB = 243 volts
BC = 236 volts

AC = 238 volts

Average Voltage =

Determine maximum deviation from average voltage:

(AB) 243 - 239 = 4 volts
(BC) 239 - 236 = 3 volts
(AC) 239 - 238 = 1 volt

Maximum deviation is 4 volts. Determine % voltage
imbalance:

% Voltage Imbalance = 100 x —^ = 1.7%

This amount of phase imbalance is satisfactory as it is

below the maximum allowable 2%.

IMPORTANT: Contact your local electric utility
company immediately if the supply voltage phase
imbalance is more than 2%.

243 + 236 + 238 = 239 volts

239

IMPORTANT: Ensure power to the crankcase
heater is always on (except when servicing the unit).
If circuit breakers inside unit shut down the com
pressor and condenser fans, crankcase heater
remains on.

NOTES:

1

THERE MUST BE [1220 mm] 4 ft FOR SERVICE AND
FOR UNRESTRICTED AIRFLOW ON ALL SIDES OF UNIT.

THERE MUST BE MINIMUM C2440 mml 8 ft CLEAR
AIR SPACE ABOVE UNIT.

THE APPROXIMATE OPERATING WEIGHT OF THE UNIT IS:

3.
60 HZ

UNIT WT LBS

38AK024

1456 661

38AK024C 1580

NOTE: "C" INDICATES COPPER COIL.

2 4

WT KG

717

50 HZ

UNIT WT LBSWT KG
38AK024
38AK024C 1580

60 Hz
024
024C

50 Hz
024
024c

1456 661

717

APPROX. OPER. WT. (LB.)

AT SUPPORT POINTS

1 2

411

501

448 533

587

433

626

462

245
273 326

486 358
518

HINGED ACCESS DOOR•

CONTROL BOX

3 4

299

382

TOT.
1456
1580

1864
1988

[63.5-92.1] 2 1/2'-:
FIELD MAIN POWER SU

- A

' II

HINGED ACCES

[1315]

4'-3 3/4'

[61]

2 7/16

[19.1]

3/4' dia;
MOUNTING HOLES

(TYP 4 PLACES)

[63.5-92.1]
2 1/2'-3 5/8'DIA.
FIELD POWER
ENTRY 8 LIFTING

[22.2]

7/8' DIA.
FIELD CONTROL
POWER ENTRY

Fig. 6 — Dimensioi

ECimON

PAM No. 2

5/8' DIA.

LY

[22.2] 7/8' DIA.
FIELD CONTROL CIRCUIT WIRING

TOP VIEW

1 Drawing, 38AK024

10'-7 13/16'

SIDE VIEW