Carrier 38MBR series Service Manual

38MBR Outdoor Unit Single Zone Ductless System Sizes 36 to 48

Service Manual

TABLE OF CONTENTS

PAGE

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

INTRODUCTION 1...................................

MODEL/SERIAL NUMBER NOMENCLATURE 2..........

SPECIFICATIONS − OUTDOOR 3.......................

DIMENSIONS − OUTDOOR 4..........................

CLEARANCES − OUTDOOR 6.........................

ELECTRICAL DATA 7................................

WIRING 7...........................................

CONNECTION DIAGRAM 7...........................

WIRING DIAGRAMS 8................................

FAN AND MOTOR SPECIFICATIONS 12.................

REFRIGERATION CYCLE DIAGRAMS 13................

REFRIGERANT LINES 14.............................

SYSTEM EVACUATION AND CHARGING 15.............

SYSTEM VACUUM AND CHARGE 15...................

ELECTRONIC FUNCTIONS 16.........................

TROUBLESHOOTING 18..............................

DIAGNOSIS GUIDES 19...............................

DIAGNOSIS AND SOLUTION 20.......................

DISASSEMBLY INSTRUCTIONS SIZE 36 38..............

DISASSEMBLY INSTRUCTIONS SIZE 48 44..............

SAFETY CONSIDERATIONS

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

Only trained, qualified installers and service mechanics should install, start−up, and service this equipment.

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.

Read this manual thoroughly and follow all warnings or cautions included in literature and attached to the unit. Consult local building codes and National Electrical Code (NEC) for special requirements.

Recognize safety information. This is the safety−alert symbol When you see this symbol on the unit and in instructions or manuals, be alert to the potential for personal injury. Understand these signal words: DANGER, WARNING, and CAUTION.

These words are used with the safety−alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

ELECTRICAL SHOCK HAZARD

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

Before installing, modifying, or servicing system, main electrical disconnect switch must be in the OFF position. There may be more than 1 disconnect switch. Lock out and tag switch with a suitable warning label.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

Do not bury more than 36 in. (914 mm) of refrigerant pipe in the ground. If any section of pipe is buried, there must be a 6 in. (152 mm) vertical rise to the valve connections on the outdoor units. If more than the recommended length is buried, refrigerant may migrate to the cooler buried section during extended periods of system shutdown. This causes refrigerant slugging and could possibly damage the compressor at start−up.

INTRODUCTION

This Service Manual provides the necessary information to service, repair, and maintain the 38MBR family of heat pumps. Section 2 of this manual has an appendix with data required to perform troubleshooting. Use the Table of Contents to locate a desired topic.

WARNING

EXPLOSION HAZARD

Failure to follow this warning could result in death, serious personal injury, and/or property damage.

Never use air or gases containing oxygen for leak testing or operating refrigerant compressors. Pressurized mixtures of air or gases containing oxygen can lead to an explosion.

CAUTION

MODEL/SERIAL NUMBER NOMENCLATURE

Table 1—Unit Sizes

SYSTEM TONS kBTUh VOLTAGE - PHASE OUTDOOR MODEL

3.00 36 208/230-1 38MBRQ36A--3

4.00 48 208/230-1 38MBRQ48A-- 3

OUTDOOR UNIT

- -

38 = OUTDOOR UNIT

MB = MODEL

UNIT TYPE: R = OUTDOOR UNIT

SYSTEM TYPE: Q=HEAT PUMP

38 MB 336

QRA

VOLTAGE 3 = 208/230-1-60

NOT USED

NOMINAL CAPACITY 36 - 3 TONS 48 - 4 TONS

Week of Manufacture

Year of Manufacture

25 16

Use of the AHRI Certified TM Mark indicates a manufacturer’s participation in the program For verification of certification for individual products, go to www.ahridirectory.org.

V = ALL MODELS

MAXIMUM NUMBER OF FAN COIL UNITS THAT CAN BE CONNECTED TO THE OUTDOOR UNIT

A=1:1

10001

Sequential Serial Number

SPECIFICATIONS − OUTDOOR

System

Electrical

Operating Range

Piping

Refrigerant

Outdoor Coil

Compressor

Outdoor

Size 36 48 Outdoor Model 38MBRQ36A-- 3 38MBRQ48A-- 3 Voltage, Phase, Cycle V/Ph/Hz 208/230-1-60 208/230-1-60 MCA A. 30 35 MOCP - Fuse Rating A. 50 50 Cooling Outdoor DB Min - Max °F (°C) -4~ 122 (-20~ 50) -4~ 122 (-20~ 50) Heating Outdoor DB Min - Max °F (°C) -22~ 86 (-30~ 30) -22~ 86 (-30~ 30) Total Piping Length ft (m) 213 (65) 213 (65) Piping Lift Pipe Connection Size - Liquid in (mm) 3/8 (9.52) 3/8 (9.52) Pipe Connection Size - Suction in (mm) 5/8 (16) 5/8 (16) Ty pe R410A R410A Charge lbs (kg) 6.72 (3.05) 9.26 (4.2) Metering Device EEV EEV Face Area Sq. Ft. 8.0 13.6 No. Rows 2 2 Fins per inch 18 18 Circuits 4 8 Ty pe Rotary Inverter Rotary Inverter Model ATF310D43UMT ATQ420D1UMU Oil Type ESTER OIL VG74 ESTER OIL VG74 Oil Charge Fl. Oz. 28.2 39.5 Rated Current RLA 8.9 11.9 Unit Width in (mm) 40.63 (1032) 40.63 (1032) Unit Height in (mm) 31.89 (810) 52.48 (1333) Unit Depth in (mm) 17.91 (544) 17.64 (448) Net Weight lbs (kg) 136.47 (61.9) 217.4 (98.6) Airflow CFM 2,130 4,500 Sound Pressure dB(A) 63.0 62.5

Table 2—Outdoor

HEAT PUMP

ft (m) 98 (30) 98 (30)

* Condensing unit above or below indoor unit

DIMENSIONS − OUTDOOR

Fig. 1 – Sizes 36K

Table 3—Dimensions

UNIT SIZE WIDTH in (mm) DEPTH in (mm) HEIGHT in (mm) L1 in (mm) L2 in (mm)

36K 37.24 (946) 16.14 (410) 31.89 (810) 26.50 (673) 15.87 (403) 136.47 (61.9)

OPERATING

WEIGHT lb (kg)

DIMENSIONS − OUTDOOR (CONT)

Fig. 2 – Sizes 48K

Table 4—Dimensions

UNIT SIZE WIDTH in (mm) DEPTH in (mm) HEIGHT in (mm) L1 in (mm) L2 in (mm)

48K 37.22 (945) 15.58 (396) 52.48 (1333) 24.96 (634) 15.90 (404) 217.4 (98.6)

OPERATING

WEIGHT lb (kg)

CLEARANCES − OUTDOOR

Air-inlet

Air-outlet

A07894

Fig. 3 – Outdoor Unit Clearance

UNIT

A 24 (610) B 24 (610) C 24 (610) D 4 (101) E 4 (101)

MINIMUM VALUE

in. (mm)

NOTE: Outdoor Unit must be mounted at least 2in (50mm) above the maximum anticipated snow depth.

ELECTRICAL DATA

Table 5—Single Zone Outdoor Unit

OUTDOOR UNIT SIZE 36K 48K

Volts-PH-Hz 208/230-1-60 208/230-1-60

Max – Min* Oper. Voltage 253-187 253-187

Power Supply

Compressor

*Permissible limits of the voltage range at which the unit will operate satisfactorily.

LEGEND

FLA - Full Load Amps MCA - Minimum Circuit Amps RLA - Rated Load Amps

MCA 30 35

Max Fuse/

CB AMP

Volts-PH-Hz 208/230-1-60 208/230-1-60

RLA 8.85 11.86

50 50

WIRING

All wires must be sized per NEC (National Electrical Code) or CEC (Canadian Electrical Code) and local codes. Use the Electrical Data table MCA (minimum circuit amps) and MOCP (maximum over current protection) to correctly size the wires and the disconnect fuse or breakers respectively.

Per the caution note, only stranded copper conductors with a 600 volt rating and double insulated copper wire must be used. The use of BX cable is not recommended.

Recommended Connection Method for Power and Communication Wiring −

Power and Communication Wiring:

The main power is supplied to the outdoor unit. The field supplied 14/3 power/communication wiring from the outdoor unit to the indoor unit consists of four (4) wires and provides the power for the indoor unit. Two wires are high voltage AC power, one is communication wiring and the other is a ground wire.

Recommended Connection Method for Power and Communication Wiring (To minimize communication

wiring interference)

Power Wiring:

The main power is supplied to the outdoor unit. The field supplied power wiring from the outdoor unit to the indoor unit consists of three (3) wires and provides the power for the indoor unit. Two wires are high voltage AC power and one is a ground wire. To minimize voltage drop, the factory recommended wire size is 14/2 stranded with a ground.

Communication Wiring:

A separate shielded stranded copper conductor only, with a 600 volt rating and double insulated copper wire, must be used as the communication wire from the outdoor unit to the indoor unit. Please use a separate shielded 16GA stranded control wire.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

S Wires should be sized based on NEC and local codes.

S Use copper conductors only with a minimum 600 volt

rating and double insulated copper wire.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

SBe sure to comply with local codes while running wire from

the indoor unit to the outdoor unit.

SEvery wire must be connected firmly. Loose wiring may

cause the terminal to overheat or result in unit malfunction. A fire hazard may also exist. Therefore, ensure all wiring is tightly connected.

SNo wire should be allowed to touch the refrigerant tubing,

compressor or any moving parts.

SDisconnecting means must be provided and shall be located

within sight and readily accessible from the air conditioner.

SConnecting cable with conduit shall be routed through a hole

in the conduit panel.

CAUTION

CONNECTION DIAGRAM

Notes:

1. Do not use the thermostat wire for any connection between indoor and outdoor units.

2. All connections between indoor and outdoor units must be as shown. The connections are sensitive to polarity and will result in a fault code.

A150688

Fig. 4 – Connection Diagrams

WIRING DIAGRAMS

Applicable to the units adopting DC motor only

CN19

CN55

CN53

CN52

CN54

DRIVER BOARD

BLUE

Y/G

COMP

BLACK

RED

BLUE

CN51

L-PRO

H-PRO

FM1

Y/G

EEV

Y/G

KCALBKCALB

RED

4-WAY1

BLUE

HEAT_Y

OPTIONAL

HEAT_D

BLACK

RED

BLUE

RED

CN43

CN3

CN4

CN10

CN5

CN6

BLUE

BLACK

CN41

CN42

CN22

CN40

CN44

CN7

CN34

CN9

MAIN BOARD

LAN

NOI O

ITPO T PO

CN8

CN33

CN20

P-1

CN2

CN1

BLACK

RED

YELLOW

XT2

TO INDOOR COMM. BUS

NOTEφ shielded wire.

GRAY

YELLOW

Please use 2-core

Fig. 5 – Wiring Diagram Size 36K

OUTDOOR UNIT MAIN BOARD

CODE PART NAME

CN1~CN2 Input: 230VAC High voltage CN5~CN6 Output: 230VAC High voltage P-1 Connection to the earth CN10~CN44 Output: 230VAC High voltage Chassis Crankcase Heater CN4~CN40 Output: 230VAC High voltage Compressor Crankcase Heat CN3~CN22 Output: 230VAC High voltage CN43 Output: Pin3~Pin2, Pin4~Pin2 (230 VAC High voltage) For AC FAN CN41~CN42 Output To AC FAN Capacitor CN34 Output:-24VDC-24VDC CN33 Input: Pin 1 (0-5VDC),Pin 2 (5VDC) Discharge Temperature Sensor CN8 Input: Pin3, Pin4 (5VDC),Pin2 (0VDC),Pin1,Pin5 (0-5VDC) T3 & T4 CN9 Input: Pin2, Pin4 (0VDC),Pin1,Pin3 (0-5VDC) H/L Pressure Switch CN20 Output: Pin1-Pin4: Pulse waveform(0-12VDC),Pin5, Pin6 (12VDC) CN7 Output: Pin1 (12VDC),Pin2 (5VDC),Pin3 (EARTH)

(2)L2

(1)L1

TO INDOOR UNIT POWER SUPPLY

MAIN POWER SUPPLY

XT1

OPTIONAL

WIRING DIAGRAMS (CONTINUED)

OUTDOOR UNIT PFC & IPM BOARD

CODE PART NAME

CN53~CN54 Input: 230VAC High voltage

CN55 Output: Pin1 (12VDC),Pin2 (5VDC),Pin3 (EARTH)

CN19 Pin1~Pin3: Connect to FAN voltage among phases 0~200VAC

U~V~W Connect to compressor voltage among phases 0~200VAC

CN51~CN52 CN51~EARTH ,CN52~EARTH Output: 224-380VDC High voltage

CODE PART NAME CODE PART NAME

COMP COMPRESSOR L PFC INDUCTOR

CAP1 FAN MOTOR CAPACITOR L-PRO LOW PRESSURE SWITCH

HEAT CRANKCASE HEATING H-PRO HIGH PRESSURE SWITCH

FM1 OUTDOOR DC FAN SV 4-WAY VALVE

FAN1 OUTDOOR AC FAN T3 CONDENSER TEMPERATURE SENSOR

EEV ELECTRONIC EXPANSION VALVE T4 OUTDOOR AMBIENT TEMPERATURE SENSOR

WIRING DIAGRAMS (CONTINUED)

Notes: This symbol indicates the element is optional,the actual shape shall

e prevail.

BLACK

YELLOW

CN2

RED

CN1

CH2

Ferrite bead

CH2

Ferrite bead

BLACK

RED

CN4

CT1

CN2

MAIN BOARD

CH1

CN6

CN3

BLUE

RED

CH2

BLACK

CN1

DC MOTOR

CN9

CON1

CN12

CN6

CN8

Ferrite bead

COMP

Y/G

Ferrite bead

CH2

IPM & PFC BOARD

FAN1

Ferrite bead

DRIVER BOARD

Y/G

DCFAN2

DCFAN1

FAN1

FAN2

PA IQ I

Y/G

CN15

CN10

ELECTRONIC EXPANSIVE

VE A

RED

ORP

Fig. 6 – Wiring Diagram − Size 48K

WIRING DIAGRAM (OUTDOOR UNIT)



CN3

CN1

CN22

CN20

CN19

CN25

CN24

CN18

CN17

CN9

CN28

EPIP

EI N

CN31

MET P

CN36

O SNES. O

CN32

CN27 CN34

YELLOW

H-PRO

Y/G

BLACK

WIHTE /RED

BLUE /BLACK

RED

BLACK

RED

ORANGE

BLUE

Y/G

XT1

4-WAY

Ferrite bead

MAIN

XT2

(2)N

(2)L2

(1)N

(1)L1

OPTIONAL

HEAT_D

HEAT_Y

OPTIONAL

XT2

Ferrite bead

TO INDOOR COMM. BUS

NOTEφ

shielded wire.

POWER SUPPLY

TO INDOOR UNIT

LEY

YARG

WOL

Please use 2-core

CODE PART NAME

CN1~CN3 Input: 230VAC High voltage

P7~P8 Output: 230VAC High voltage to IDU

P5,P6,P9 Connection to the earth

CN22 Output:-24VDC-24VDC for IDU Communication

CN17~CN18 Output: 230VAC High voltage 4 way valve

CN19~CN20 Output: 230VAC High voltage Chassis Crankcase Heater

CN24~CN25 Output: 230VAC High voltage Compressor Crankcase Heater

CN2~CN4 Output: 230VAC High voltage to AC CURRENT DETECTOR

CN12 Input: Pin1 (0-5VDC),Pin2 (5VDC) Heatsink Temperature Sensor

CN8 Input: Pin1 (0-5VDC),Pin2 (5VDC) Compressor Top Sensor(PAIQI)

CN9 Input: Pin3,Pin4 (5VDC),Pin2 (0VDC),Pin1,Pin5 (0-5VDC) the ambient sensor and pipe sensor

CN10 Input: Pin2, Pin4 (0VDC),Pin1,Pin3 (0-5VDC) for the H/L pressure switch

CN15 Output: Pin1-Pin4: Pulse waveform (0-12VDC),Pin5, Pin6 (12VDC) EEV

CN6 Output: Pin1-Pin6: Pulse waveform (0-5VDC), Pin7, Pin9 (0VDC) Pin8 (0-5VDC), Pin10 (5VDC)

OUTDOOR UNIT MAIN BOARD

WIRING DIAGRAMS (CONTINUED)

OUTDOOR UNIT PFC & IPM BOARD

CODE PART NAME

CN1~CN6 Output:224-380VDC High voltage to DIODE MODULE

CN2~CN3 Output:224-380VDC High voltage to PFC INDUCTOR

U~V~W Connection to compressor voltage among phases 0~200VAC

CN9 Input:Pin1-Pin6: Pulse waveform (0-5VDC),Pin7, Pin9 (0VDC) Pin8 (0-5VDC),Pin10 (5VDC)

FAN1 Output: Pin1~Pin2: High voltage (224-380VDC), Pin4 (0-15VDC) Pin5 (0-5.6VDC), Pin6:Pulse waveform (0-15VDC)

OUTDOOR UNIT DC MOTOR DRIVER BOARD

CODE PART NAME

CON1 Output:Pin1~Pin2:High voltage (224-380VDC)

CN1 Input: Pin4: Pulse waveform (0-15VDC) ,Pin3 (0-6.5VDC) Pin2 (0VDC),Pin1 (15VDC)

FAN1 Pin1-Pin3: Connect to FAN voltage among phases 0~200VAC

FAN2 Pin1-Pin3: Connect to FAN voltage among phases 0~200VAC

CODE PART NAME

COMP COMPRESSOR CAP1,CAP2 FAN MOTOR CAPACITOR CT1 AC CURRENT DETECTOR D DIODE MODULE EEV ELECTRONIC EXPANSION VALVE FM1,FM2 OUTDOOR DC FAN FAN1,FAN2 OUTDOOR AC FAN HEAT CRANKCASE HEATING H-PRO HIGH PRESSURE SWITCH L PFC INDUCTOR L-PRO LOW PRESSURE SWITCH KM AC CONTACTOR SV 4-WAY VALVE TP EXHAUST TEMPERATURE SENSOR T3 CONDENSER TEMPERATURE SENSOR T4 OUTDOOR AMBIENT TEMPERATURE SENSOR TH HEATSINK TEMPERATURE SENSOR PAIQI COMPRESSOR TOP SENSOR (GAS PIPE SENSOR) CH 1

CH 2 CH 3

FERRITE BEAD

FAN AND MOTOR SPECIFICATIONS

System Size 36K 48K

Material -- AS AS

Outdoor Fan Propeller

Outdoor Fan Motor

Type -- ZL-560*139*12-3KN ZL-554*148*12-3KFN

Diameter in 560 554

Height in 139 148

Model -- WZDK120-38G-W ZKFN-85-8-22

Type -- DC DC

Phase -- 1 1

FLA A 1.21 1.17

Insulation Class -- E E

Safe Class -- IPX0 IPX0

Input W 150 126

Output W 120 85

Range of current A 1.21±10% 1.17±10%

Rated current A 1.21 1.17

Capacitor µF N/A N/A

Rated HP HP 0.16 0.14

Speed rev/min 850/800/750 900/850/750

Rated RPM rev/min 1050 900

Max. input W 150 126

REFRIGERATION CYCLE DIAGRAMS

INDOOR OUTDOOR

HEAT EXCHANGE (EVAPORATOR)

T2 Evaporator temp. sensor middle

T2B Evaporator temp. sensor outlet

T1 Room temp. sensor

LIQUID SIDE

2-WAY VALVE

GAS SIDE

3-WAY VALVE

CAPILIARY TUBE

Compressor

Electronic expansion valve

T4 Ambient temp. sensor

4-WAY VALVE

T5 Discharge temp. sensor

T3 Condenser temp. sensor

COOLING

HEATING

HEAT EXCHANGE (CONDENSER)

Fig. 7 – Refrigerant Cycle Diagrams

REFRIGERANT LINES

General refrigerant line sizing:

1 The outdoor units are shipped with a full charge of R410A

refrigerant. All charges, line sizing, and capacities are based on runs of 25 ft. (7.6 m) per number of zones. For runs over 25 ft. (7.6 m), consult long−line section on this page for proper charge adjustments.

2 Minimum refrigerant line length between the indoor and

outdoor units is 10 ft. (3 m).

IMPORTANT: Both refrigerant lines must be insulated separately.

S Table 6 provides the maximum lengths allowed:

Table 6—Piping and Refrigerant

SYSTEM SIZE 36K 48K

Min. Piping Length ft(m) 10(3) 10(3)

Standard Piping Length ft(m) 25(7.5) 25(7.5)

Max. outdoor-indoor height difference (OU higher than IU) ft(m) 98(30) 98(30)

Max. outdoor-indoor height difference (IU higher than OU) ft(m) 98(30) 98(30)

PIPING

REFRIGERANT

Max. Piping length with no additional refrigerant charge ft(m) 26(8) 26(8)

Max. Piping Length ft(m) 213(65) 213(65)

Additional refrigerant charge

(between Standard - Max piping length)

Gas Pipe (size-connection type) in(mm) 5/8(16) 5/8(16)

Liquid Pipe (size-connection type) in(mm) 3/8(9.52) 3/8(9.52)

Refrigerant Type -- R410A R410A

Charge Amount Lbs(kg) 6.72(3.05) 9.26(4.2)

3 Refrigerant lines should not be buried in the ground. If it is

necessary to bury the lines, not more than 36−in (914 mm) should be buried. Provide a minimum 6−in (152 mm) vertical rise to the service valves to prevent refrigerant migration.

4 Both lines must be insulated. Use a minimum of 1/2−in.

(12.7 mm) thick insulation. Closed−cell insulation is recommended in all long−line applications.

5 Special consideration should be given to isolating

interconnecting tubing from the building structure. Isolate the tubing so that vibration or noise is not transmitted into the structure.

Oz/ft(g/m) 0.43(40) 0.43(40)

Long Line Applications,:

1 No change in line sizing is required. 2 Add refrigerant per Table 7.

TOTAL LINE

UNIT SIZE

LENGHT ft

Min Max

10 213 None 0.43

Table 7—Additional Charge Table Per Zone

ADDITIONAL CHARGE, oz/ft. Ft (m)

>10-25

(3-8)

>25-213

(8-65)

SYSTEM EVACUATION AND

CHARGING

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

Never use the system compressor as a vacuum pump.

Refrigerant tubes and indoor coil should be evacuated using the recommended deep vacuum method of 500 microns. The alternate triple evacuation method may be used if the following procedure is followed. Always break a vacuum with dry nitrogen.

NOTE: All units (except the 18,000 BTU model) have a Master Suction and Liquid Line Service Valve.

CAUTION

SYSTEM VACUUM AND CHARGE

Using Vacuum Pump

1 Completely tighten the flare nuts (A, B, C, D, E). Fully

open all circuits service valves. Connect the manifold gage charge hose to the charge port of the low side Master service valve to evacuate all circuits at the same time (see Fig. 8).

2 Connect charge hose to vacuum pump. 3 Fully open the low side of manifold gage (see Fig. 9).

4 Start vacuum pump

5 Evacuate using the triple evacuation method. 6 After evacuation is complete, fully close the low side of

manifold gage and stop operation of vacuum pump.

7 The factory charge contained in the outdoor unit is good for

up to 25ft. (8 m) of line length. For refrigerant lines longer than 25ft. (8 m), add refrigerant as specified in the ADDITIONAL REFRIGERANT CHARGE table in this document.

8 Disconnect charge hose from charge connection of the low

side service valve.

9 Securely tighten caps of service valves.

Outdoor Unit

Service Valve

500 microns

Low side valve

Charge hose

Refrigerant

Low Side

High Side

Fig. 8 – Service Valve

Manifold Gage

High side valve

Charge hose

Indoor Uni

Vacuum pump

Deep Vacuum Method

The deep vacuum method requires a vacuum pump capable of pulling a vacuum of 500 microns and a vacuum gage capable of accurately measuring this vacuum depth. The deep vacuum method is the most positive way of assuring a system is free of air and liquid water (see Fig. 10).

5000 4500 4000 3500 3000 2500 2000

MICRONS

1500 1000

500

01234567

MINUTES

LEAK IN SYSTEM

VACUUM TIGHT TOO WET

TIGHT DRY SYSTEM

Fig. 10 – Deep Vacuum Graph

Triple Evacuation Method

The triple evacuation method should be used. Refer to Fig. 11 and proceed as follows:

1 Pump system down to 500 MICRONS of mercury and

allow pump to continue operating for an additional 15 minutes. Unit must maintain 500 microns or less for 30

minutes or more to ensure a dry system. 2 Close service valves and shut off vacuum pump.

3 Connect a nitrogen cylinder and regulator to system and

open until system pressure is 2 psig. 4 Close service valve and allow system to stand for 10

minutes. During this time, dry nitrogen will be able to

diffuse throughout the system absorbing moisture.

5 Repeat this procedure as indicated in Fig. 11. System will

then be free of any contaminants and water vapor.

EVACUATE

BREAK VACUUM WITH DRY NITROGEN

WAIT

EVACUATE

BREAK VACUUM WITH DRY NITROGEN

WAIT

EVACUATE

CHECK FOR TIGHT, DRY SYSTEM

(IF IT HOLDS DEEP VACUUM)

RELEASE CHARGE INTO SYSTEM

Fig. 11 – Triple Evacuation Method

Final Tubing Check IMPORTANT: Check to be certain factory tubing on both

indoor and outdoor unit has not shifted during shipment. Ensure tubes are not rubbing against each other or any sheet metal. Pay close attention to feeder tubes, making sure wire ties on feeder tubes are secure and tight.

Low side valve

Fig. 9 – Manifold

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Carrier 38MBR series Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual