R410A

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

March 2015

TECHNICAL & SERVICE MANUAL

No. OCH574

REVISED EDITION-A

[Model Name]

<Branch box>

[Service Ref.]

PAC-MK50BC

PAC-MK50BC

PAC-MK30BC

PAC-MK30BC

(Indispensable optional parts for

PUMY-P112/125/140VKM1 and PUMY-P112/125/140YKM1)

Revision:

•

Corrected some errors in "7-1.

HOW TO CHECK THE PARTS" in REVISED EDITION-A.

• Some descriptions have been modified.

• Please void OCH574.

Note:

• This service manual describes technical data of branch box. As for indoor units and outdoor unit, refer to its service manual.

BRANCH BOX

CONTENTS

1. SAFETY PRECAUTION ······································· 2

2. OVERVIEW OF UNIT ··········································· 5

3. SPECIFICATIONS ················································ 8

4. OUTLINES AND DIMENSIONS ··························· 9

5. WIRING DIAGRAM ············································· 10

6. NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION··············11

7. TROUBLESHOOTING ········································ 15

8. DISASSEMBLY PROCEDURE ··························· 24

PARTS CATALOG (OCB574)

1 SAFETY PRECAUTION

1-1. ALWAYS OBSERVE FOR SAFETY

Before obtaining access to terminal, all supply circuit must be disconnected.

1-2. CAUTIONS RELATED TO NEW REFRIGERANT

Cautions for units utilizing refrigerant R410A

Use new refrigerant pipes.

Make sure that the inside and outside of refrigerant piping is clean and it has no contaminants such as sulfur, oxides, dirt, shaving particles, etc, which are hazard to refrigerant cycle.

In addition, use pipes with specified thickness.

Contamination inside refrigerant piping can cause deterioration of refrigerant oil, etc.

Store the piping indoors, and both ends of the piping sealed until just before brazing.

(Leave elbow joints, etc. in their packaging.)

If dirt, dust or moisture enters into refrigerant cycle, that can cause deterioration of refrigerant oil or malfunction of compressor.

The refrigerant oil applied to flare and flange connections must be ester oil, ether oil or alkylbenzene oil in a small amount.

If large amount of mineral oil enters, that can cause deterioration of refrigerant oil, etc.

Charge refrigerant from liquid phase of gas cylinder.

If the refrigerant is charged from gas phase, composition change may occur in refrigerant and the efficiency will be lowered.

Use the specified refrigerant only.

Never use any refrigerant other than that specified.

Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.

Correct refrigerant is specified in the manuals and on the spec labels provided with our products.

We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions.

Do not use refrigerant other than R410A.

If other refrigerant (R22, etc.) is used, chlorine in refrigerant can cause deterioration of refrigerant oil, etc.

Use a vacuum pump with a reverse flow check valve.

Vacuum pump oil may flow back into refrigerant cycle and that can cause deterioration of refrigerant oil, etc.

Use the following tools specifically designed for use with R410A refrigerant.

The following tools are necessary to use R410A refrigerant.

Gauge manifold

Charge hose

Gas leak detector

Torque wrench

Tools for R410A

Flare tool

Size adjustment gauge

Vacuum pump adaptor

Electronic refrigerant charging scale

Handle tools with care.

If dirt, dust or moisture enters into refrigerant cycle, that can cause deterioration of refrigerant oil or malfunction of compressor.

Do not use a charging cylinder.

If a charging cylinder is used, the composition of refrigerant will change and the efficiency will be lowered.

Ventilate the room if refrigerant leaks during operation. If refrigerant comes into contact with a flame, poisonous gases will be released.

OCH531A

2

[1] Cautions for service

(1) Perform service after recovering the refrigerant left in unit completely.

(2) Do not release refrigerant in the air.

(3) After completing service, charge the cycle with specified amount of refrigerant.

(4) When performing service, install a filter drier simultaneously.

Be sure to use a filter drier for new refrigerant.

[2] Additional refrigerant charge

When charging directly from cylinder

· Check that cylinder for R410A on the market is a syphon type.

· Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)

Unit

Gravimeter

[3] Service tools

(1) Use the below service tools as exclusive tools for R410A refrigerant.

No.

Tool name

1

Gauge manifold

Specifications

· Only for R410A

· Use the existing fitting specifications. (UNF1/2)

· Use high-tension side pressure of 5.3MPa·G or over.

· Only for R410A

· Use pressure performance of 5.09MPa·G or over.

2

Charge hose

3

Electronic scale

4

Gas leak detector

5

Adaptor for reverse flow check

6

Refrigerant charge base

7

Refrigerant cylinder

8

Refrigerant recovery equipment

· Use the detector for R134a, R407C or R410A.

· Attach on vacuum pump.

· Only for R410A · Top of cylinder (Pink)

· Cylinder with syphon

OCH531A

3

(2) Cautions for refrigerant piping work

New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working pressure of R410A is 1.6 times higher than that of R22, their sizes of flared sections and flare nuts are different.

1

Thickness of pipes

Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness shown below. (Never use pipes of 0.7 mm or below.)

Diagram below: Piping diameter and thickness

Nominal dimensions (in)

1/4

3/8

1/2

5/8

3/4

Outside diameter (mm)

6.35

9.52

12.70

15.88

19.05

Thickness (mm)

R410A

0.8

0.8

0.8

1.0

—

R22

0.8

0.8

0.8

1.0

1.0

2

Dimensions of flare cutting and flare nut

The component molecules in HFC refrigerant are smaller compared to conventional refrigerants. In addition to that,

R410A is a refrigerant, which has higher risk of leakage because of its working pressure higher than that of other refrigerants. Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been specified separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also has partly been changed to increase strength as shown below. Set copper pipe correctly referring to copper pipe flaring dimensions for R410A below. For 1/2” and 5/8” inch pipes, the dimension B changes.

Use torque wrench corresponding to each dimension.

Dimension A

Flare cutting dimensions

Nominal dimensions (in)

1/4

3/8

1/2

5/8

3/4

Outside diameter (mm)

6.35

9.52

12.70

15.88

19.05

Dimension A ( )

R410A

(mm)

R22

9.1

13.2

16.6

19.7

—

9.0

13.0

16.2

19.4

23.3

Dimension B

Flare nut dimensions

Nominal dimensions (in)

1/4

3/8

1/2

5/8

3/4

Outside diameter (mm)

6.35

9.52

12.70

15.88

19.05

Dimension B (mm)

R410A

17.0

22.0

26.0

29.0

—

R22

17.0

22.0

24.0

27.0

36.0

3

Tools for R410A (The following table shows whether conventional tools can be used or not.)

Tools and materials

Gauge manifold

Charge hose

Gas leak detector

Refrigerant recovery equipment

Refrigerant cylinder

Applied oil

Use

Air purge, refrigerant charge and operation check

Gas leak check

Refrigerant recovery

Refrigerant charge

Apply to flared section

R410A tools

Tool exclusive for R410A

Tool exclusive for R410A

Tool for HFC refrigerant

Tool exclusive for R410A

Tool exclusive for R410A

Ester oil and alkylbenzene oil (minimum amount)

Tool exclusive for R410A Safety charger

Charge valve

Vacuum pump

Flare tool

Bender

Pipe cutter

Welder and nitrogen gas cylinder

Refrigerant charging scale

Vacuum gauge or thermistor vacuum gauge and vacuum valve

Charging cylinder

Prevent compressor malfunction when charging refrigerant by spraying liquid refrigerant

Prevent gas from blowing out when detaching charge hose

Vacuum drying and air purge

Flaring work of piping

Bend the pipes

Cut the pipes

Weld the pipes

Refrigerant charge

Check the degree of vacuum. (Vacuum valve prevents back flow of oil and refrigerant to thermistor vacuum gauge)

Refrigerant charge

Tool exclusive for R410A

Tools for other refrigerants can be used if equipped with adopter for reverse flow check

Tools for other refrigerants can be used by adjusting flaring dimension

Tools for other refrigerants can be used

Tools for other refrigerants can be used

Tools for other refrigerants can be used

Tools for other refrigerants can be used

Tools for other refrigerants can be used

Tool exclusive for R410A

: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)

: Tools for other refrigerants can be used under certain conditions.

: Tools for other refrigerants can be used.

Can R22 tools be used?

(Usable if equipped

with adopter for rever-

se flow)

(Usable by adjusting

flaring dimension)

Can R407C tools be used?

Ester oil:

Alkylbenzene oil: minimum amount

(Usable if equipped

with adopter for rever-

se flow)

(Usable by adjusting

flaring dimension)

OCH531A

4

2 OVERVIEW OF UNIT

2-1. SYSTEM OUTLINE

The additional connection of the Branch Box together with employment of the compact trunk-looking outdoor unit can successfully realizes a long distance piping for big houses. Equipped with a microprocessor, the Branch Box can translate the transmission signal of indoor units to achieve the optimum control.

2-1-1. System example

Indoor unit (Ceiling concealed type)

Outdoor unit Branch Box

2-1-2. Method for identifying

■ Outdoor unit

PU M Y - P 125 Y K M 1 - BS

Outdoor unit

Refrigerant

R410A

MULTI-S

Frequency conversion controller

Indicates equivalent to Cooling capacity

(k cal/ h)

Outdoor unit model type

Power supply

Sub number

M-NET control

Salt proof type

V: Single phase

220/230/240 V, 50 Hz

Y: 3-phase

380/400/415 V, 50 Hz

■ Branch box

Symbol of factory

P A C – M K 5 0 BC

(Indispensable)

Optional parts

Branch box (Controller)

Model type

Number of branches

5 : 5 branches

3 : 3 branches

OCH531A

5

Indoor unit

(Wall mounted type)

2-2. INSTALLATION

2-2-1. Space required for Installation and servicing for Branch box.

(1) Front View (Fig. 2-1)

A

Branch box

B

On the side of piping

(2) Side View (Fig. 2-2, Fig. 2-3)

C

For indoor installations

D

Ceiling board

E

Maintenance hole

*1:

A minimum 350 mm is required for 90° bends in refrigerant piping.

*2: A is “Min. 200 mm”.

In the case of less than 200 mm (for example A is 100 mm), the exchange work of Branch box from a maintenance hole

becomes difficult (Only exchange work of a PCB, linear expansion valve coils and sensors is possible).

*3: B is “

□

600”.

In the case of “ as distance A.

□

450”, prepare a maintenance hole at a PCB side as it is shown in Fig. 2-3, and “Min. 300 mm” is needed

In the case of less than 300 mm (for example A is 100 mm), the exchange work of Branch box, linear expansion valve coils and sensors from a maintenance hole becomes difficult. Only exchange work of a PCB is possible.

(3) Top View (Fig. 2-4)

G

Refrigerant piping

NOTE1: The branch box is only for indoor use.

NOTE2: Please attach the special optional cover (PAC-AK350CVR-E) to install branch box in the outdoors.

(1) (2)

C

unit : mm

A

50

B

450

Fig. 2-1

250

D

*1

250

180-200

278

*3

Fig. 2-2

250

E

*2

(3)

G

Min. 250

Fig. 2-4

OCH531A

Fig. 2-3

450

E D

6

2-3. SIMPLIFIED PIPING SYSTEM

Piping connection size

A

Liquid (mm)

Gas (mm)

{9.52

{15.88

B

The piping connection size differs according to the type and capacity of indoor units.

Match the piping connection size of branch box with indoor unit.

If the piping connection size of branch box does not match the piping connection size of indoor unit, use optional different-diameter (deformed) joints to the branch box side.

(Connect deformed joint directly to the branch box side.)

Flare connection employed. (No brazing!)

■ In case of using 1-branch box

Flare connection employed (No brazing)

Branch box

A

B B B B B

■ In case of using 2-branch boxes

A

2 branches pipe (joint)

: optional parts

A

B

A

B

Branch box #1

B B B

Branch box #2

■ Installation procedure (2 branch pipe (joint))

Refer to the installation manuals of MSDD-50AR-E and MSDD-50BR-E.

OCH531A

7

3 SPECIFICATIONS

PAC-MK50BC PAC-MK30BC

Model Name

Connectable number of indoor units

Power supply (from outdoor unit)

Input

Running current

External finish

Dimensions

Width

Depth

Height

Weight

Piping connection

(Flare)

Branch (indoor side)*

Main (outdoor side)

Liquid

Gas

Liquid

Gas kW

A mm mm mm kg mm mm mm mm

PAC-MK50BC

Maximum 5

PAC-MK30BC

Maximum 3

Single phase, 220/230/240V, 50Hz, Single phase, 220V, 60Hz

0.003

0.05 (Max. 6)

Galvanized sheets

450

280

170

7.4

6.7

[6.35 O 5 {A,B,C,D,E}

[9.52 O 4 {A,B,C,D}, [12.7 o 1{E}

[6.35 O 3 {A,B,C}

[9.52 O 3 {A,B,C}

[9.52

[15.88

*

The piping connection size differs according to the type and capacity of indoor units. Match the piping connection size for indoor and branch box. If the piping connection size of branch box does not match the piping connection size of indoor units, use optional different-diameter (deformed) joints to the branch box side. (Connect deformed joint directly to the branch box side.)

OCH531A

8

4 OUTLINES AND DIMENSIONS

PAC-MK50BC

SUSPENSION BOLT PITCH

320

SUSPENSION BOLT : W3/8(M10)

REFRIGERANT PIPE FLARED CONNECTION

LIQUID PIPE

GAS PIPE

A B C D E TO OUTDOOR UNIT

1/4F 1/4F 1/4F 1/4F 1/4F 3/8F

3/8F 3/8F 3/8F 3/8F 1/2F 5/8F

67

450

TO INDOOR UNIT

E

E

D

D

C

C

B

B

A

A

90

72

25

70

25

70

25

70

25

70

25

PAC-MK30BC

96

83 87 70

280

12

40

5-ELECTRIC WIRE INLET

TO OUTDOOR UNIT

SERVICE PANEL

(for LEV,THERMISTOR)

CONTROL COVER

BUSH

SUSPENSION BOLT PITCH

320

unit: mm

TERMINAL BLOCK

TO M-NET UNIT

TERMINAL BLOCK

TO INDOOR UNIT

TERMINAL BLOCK

TO OUTDOOR UNIT

SUSPENSION BOLT : W3/8(M10)

REFRIGERANT PIPE FLARED CONNECTION

LIQUID PIPE

GAS PIPE

A

1/4F

3/8F

B

1/4F

3/8F

C

1/4F

3/8F

TO OUTDOOR UNIT

3/8F

5/8F

209

CAP

452

TO INDOOR UNIT

90

72

C

C

B

B

A

A

CAP

25

70

25

70

25

12

96

83 87

280

70

40

5-ELECTRIC WIRE INLET

TO OUTDOOR UNIT

SERVICE PANEL

(for LEV.THERMISTOR)

CONTROL COVER

BUSH

TERMINAL BLOCK

TO M-NET UNIT

TERMINAL BLOCK

TO INDOOR UNIT

TERMINAL BLOCK

TO OUTDOOR UNIT

OCH531A

9

5 WIRING DIAGRAM

PAC-MK50BC PAC-MK30BC

Note : " PAC - MK30 . 50BC " is only for R410A.

SYMBOL

B.C.

F1 <B.C.>

F2~F4 <B.C.>

SW1 <B.C.>

SW4 <B.C.>

SW5 <B.C.>

CNM <B.C.>

LED1,2 <B.C.>

LEV-A~E

TH-A~E

TB2B

TB5

TB3A~E <B.C.>

SW11 <B.C.>

SW12 <B.C.>

NAME

Branch box controller board

Fuse <T6.3AL 250V>

Fuse <T10AL 250V>

Switch for indoor unit connection *1

Switch for mode selection

Not in use

Connector <Connection for service>

Light emitting diode *2

Linear expansion valve *3

Thermistor <Gas pipe> *3

Terminal block <To Power Supply>

Terminal block <Transmission>

Terminal block To indoor unit-A~E *3

Address Setting 1s DIGIT

Address Setting 10ths DIGIT

<Note>

1. At servicing for outdoor unit,

always follow the wiring diagram

of outdoor unit.

2. When work to supply power

separately to Branch box and outdoor

units are applied, refer to Fig. 1.

3. For the connection method, please

refer to the Branch box Installation

Manual.

*1 SW1 setting

OFF ON

SW1-1

SW1-2

INDOOR UNIT-A

INDOOR UNIT-B

NOT CONNECT

NOT CONNECT

CONNECT

CONNECT

SW1-3

SW1-4

SW1-5

SW1-6

INDOOR UNIT-C

INDOOR UNIT-D

INDOOR UNIT-E

NO USE

NOT CONNECT

NOT CONNECT

NOT CONNECT

CONNECT

CONNECT

CONNECT

PAC-MK

50BC only

After each indoor unit is connected to the outdoor unit, turn on the switch corresponding to each indoor unit. For example, when the indoor units are connected to INDOOR UNIT-A and C, turn SW1-1 and SW1-3 to on.

• start-up

Mark

Meaning

LED 1 Main power supply

LED 2

• normal operating

Mark

Meaning

Function

Main power supply (220/230/240V)

Power on

→ Lamps are lit

Function

LED 1 Main power supply Lamp is lit

LED 2 Total number of Blink depend on the total number indoor units <example> The total number is 2

1 Blink 2 times.

2 Turn off for three sec.

3 Repeat 1 to 2.

*2 LED on Branch box controller board for service

*3 D and E for PAC-MK50BC only.

<Combination of indoor units>

Enter the location of combined indoor units with model name in each blank below because it is necessary for service and maintenance.

Indoor unit-A Indoor unit-B Indoor unit-C

<Symbols used in wiring diagram>

: Terminal block, : Connector

: Dip switch (■(black square) indicates a switch position)

Indoor unit-D Indoor unit-E

(PAC-MK50BC only)

LEV-E

M

LEV-D

M

LEV-C

M

LEV-B

M

LEV-A

M

(PAC-MK50BC only)

TH-E

tº

TH-D

tº

TH-C

TH-B

tº

TH-A

tº tº

B.C.

5

LEV-C

(BLU)

1

5

LEV-B

(RED)

1

5

LEV-E

(GRN)

1

5

LEV-D

(BLK)

1

5

LEV-A

(WHT)

1

2 TH-E

1 (GRN)

2 TH-D

1 (BLK)

+

–

1 2 3

M-NET

CN3M

(BLU)

F1

6.3A 250V

CND

(BLK)

2 TH-C

1 (BLU)

2 TH-B

1 (RED)

2 TH-A

1 (WHT)

LED1

LED2

1

SW4

ON

OFF

1 2 3 4 5 6 7 8 9 10

SW1

ON

OFF

1 2 3 4 5 6

SW12

9

0 1

2

SW11

9

0 1

2

6

5

4

6

5

ON

OFF

10ths

DIGIT

1s

DIGIT

SW5

1 2 3 4 5 6

CNM

(WHT)

14

3

1

TB3E

S3

S2

S1

F4

10A 250V

F3

10A 250V

TB3D

S3

S2

S1

TB3C

S3

S2

S1

F2

10A 250V

TB3B

S3

S2

S1

TB1

TB3A

S3

S2

S1

BLU

BLU

TB5

M1

M2

S

TO OUTDOOR UNIT

DC24-30V

(SHIELD)

(SHIELD)

TO ANOTHER

BRANCH BOX

RED

BLU

TB2B

L

N

TO OUTDOOR UNIT

(PAC-MK50BC only)

TO

INDOOR UNIT-E

TO ANOTHER

BRANCH BOX

TO

INDOOR UNIT-D

Fig. 1

POWER SUPPLY

220/ 230/ 240V 50Hz

220V 60Hz

TO

INDOOR UNIT-C

TO

INDOOR UNI T-B

RED

BLU

TB2B

L

N

CIRCUIT

BREAKER

PULL BOX

TO ANOTHER

BRANCH BOX

TO

INDOOR UNIT-A

OCH531A

10

6 NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION

6-1. TRANSMISSION SYSTEM SETUP

89

1 2

3 4

89

1 2

3 4

City Multi Indoor unit

MA remote controller

City Multi Indoor unit

89

1 2

3 4

89

1 2

3 4

89

1 2

3 4

89

1 2

3 4

City Multi Indoor unit

MA remote controller

SW1 ON

1 2

3 4

89

1 2

3 4

89

A-control Indoor uni

A-control Indoor uni

A-control Indoor uni

MA remote controller

City Multi Indoor unit

89

1 2

3 4

1 2

3 4

89

M-NET remote controller

89

1 2

3 4

89

1 2

3 4

M-NET remote controller

1 2

89

3 4

1 2

3 4

89

City Multi Indoor unit

89

1 2

3 4

1 2

3 4

89

A-control Indoor uni

SW1 ON

A-control Indoor uni

City Multi Indoor unit

89

1 2

3 4

89

1 2

3 4

A-control Indoor uni

MA remote controller

A-control Indoor uni

MA remote controller

1 2

3 4

89

1 2

3 4

89

City Multi Indoor unit

89

1 2

3 4

89

1 2

3 4

A-control Indoor uni

MA remote controller

For centralized management

OCH531A

1 2

3 4

89

1 2

89

3 4

11

Make sure that the wiring between the branch box and indoor unit is properly done, matching with the piping connection.

For centralized management

89

1 2

3 4

1 2

3 4

89

6-2. REFRIGERANT SYSTEM DIAGRAM

■

PAC-MK50BC

B

A

E

D

C

Thermistor (TH-A–E)

(Gas pipe temperature)

LEV A–E

(Linear expansion valve)

Strainer

#100

■

PAC-MK30BC

C

B

A

Thermistor (TH-A–C)

(Gas pipe temperature)

LEV A–C

(Linear expansion valve)

Strainer

#100

Strainer

#100

Capillary

tube

Branch box

PAC-MK50BC

PAC-MK30BC unit : mm

Capillary tube behind LEV

(in cooling mode)

(

[4 o [3.0 o L130) o 5

(

[4 o [3.0 o L130) o 3

Capillary

tube

Strainer

#100

OCH531A

12

6-3. TYPICAL CONTROL SYSTEM

L

5

OC

(51)

TB3

TB7

M1 M2 S M1 M2 S

A

L

1

TB5

M1

M2

S

Branch Box TB3A

S1

S2

S3

TB3B

S1

S2

S3

TB3C

S1

S2

S3

TB3A

S1

S2

S3

A-IC

(01)

TB15

1

2

TB3A

S1

S2

S3

A-IC

(02)

TB15

1

2

TB3A

S1

S2

S3

A-IC

(03)

TB15

1

2

L

6

OC

(53)

TB7

TB3

M1 M2 S M1 M2 S

L

2

A

TB3D

S1

S2

S3

TB3E

S1

S2

S3

TB3A

S1

S2

S3

A-IC

(06)

TB15

1

2

A

Power

Supply

Unit

M1 M2 S

TB5

M1

M2

S

Branch Box TB3A

S1

S2

S3

TB3A

S1

S2

S3

A-IC

(04)

TB3A

S1

S2

S3

A-IC

(05)

L

7 System controller

M1 M2 S

24 V DC

L

3

TB3B

S1

S2

S3

TB3C

S1

S2

S3

TB3A

S1

S2

S3

A-IC

(07)

TB3A

S1

S2

S3

A-IC

(08)

A

B

MA-RC

A

B

MA-RC

A

B

MA-RC

WL-RC

WL-RC

A

B

MA-RC

WL-RC

WL-RC

A

: Shielded wire

( ): Address example

TB5

M1

M2

S

M-IC

(09)

TB15

1

2

A

B

MA-RC

L

4

TB5

M1

M2

S

M-IC

(10)

TB15

1

2

A

B

MA-RC

OC : Outdoor unit

M-IC : M-NET Control indoor unit (City Multi indoor unit)

A-IC : A-control indoor unit (M, P, S series indoor unit)

MA-RC : MA Remote controller

WL-RC : Wireless Remote controller

IMPORTANT:

Make sure that the current leakage breaker is one compatible with higher harmonics.

Always use a current leakage breaker that is compatible with higher harmonics as this unit is equipped with an inverter.

The use of an inadequate breaker can cause the incorrect operation of inverter.

Longest length via outdoor units:

L1 + L2 + L3 + L4 + L5 500 m (1640 ft.) (1.25 mm2 or more)

Longest transmission cable length

L1 + L2, L3, L3 + L4, L5 200 m (656 ft.) (1.25 mm2 or more)

(1) Difference between display and operation

1

When operating the system using the system controller or the ME remote controller, details of those operations will not appear on the display of the wireless remote controller.

2

The set temperature range is different in the wireless remote controller that comes with room air conditioner, and the ME remote controller or the system controller. The room air conditioner has a wider range. If the target temperature is set to below 17:[63-F] or less, or 30:[86-F] or more by the wireless remote controller that comes with room air conditioner, the temperature displayed on the ME remote controller or the system controller may be converted to their maximum/minimum set temperature. For instance, when HEAT operation at 16:[61-F] is set at the room air conditioner, the ME remote controller or the system controller may display 17:[63-F].

3

When the DRY mode is set with the wireless remote controller, the room air conditioner automatically set the optimum target temperature. The ME remote controller or the system controller will display the target temperature as a set temperature.

4

When the DRY mode is set with the ME remote controller, or the system controller, the room air conditioner performs the

DRY mode control operation according to the temperature set with the ME remote controller or the system controller.

(2) Timer operation

1

Timer operation should be set using only one controller from the remote controller that comes with the room air conditioner, the system controller, the MA remote controller, or the ME remote controller. If more than one controller is used to set the timer at the same time, the timer will not function properly.

2

When the timer is set with the wireless remote controller; the ME remote controller or the system controller will not show the timer display.

3

The timer set with the ME remote controller or the system controller will not be cancelled with the wireless remote controller.

(3) Manual operation prohibition

1

When the manual operation (ON/OFF, set temperature, or operation mode) is prohibited with the system controller, the command to perform the prohibited operation will not be accepted from the wireless remote controller that comes with the room air conditioner. The operation partially enabled by the system controller can be operated with the wireless remote controller. Regardless of whether the operation is disabled or enabled, three short beeps will sound when the signal is sent from the wireless remote controller.

(4) Trouble

1

If the MA remote controller, the ME remote controller, or the system controller shows the abnormal indication, clear it by stopping the operation with one of the followings: the MA remote controller, the ME remote controller, the system controller, or the wireless remote controller.

(Abnormal indication of the air conditioner could be recovered automatically, but that of the MA remote controller, the ME remote controller, or the system controller cannot be recovered unless the operation is stopped.)

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13

(5) Group setting

1

MA group or M-NET group setting cannot be set.

(6) Restricted functions

The following functions of system controller cannot be used.

• DIDO controller (Interlock with the air conditioner)

• Fan control of energy saving control or peak cut control function

• Air conditioning charge [TG-2000A]

• Set temperature range limiting function

• Operation mode changeover limit (season changing) [PAC-SF44SRA]

• Dual set point function

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14

7 TROUBLESHOOTING

7-1. HOW TO CHECK THE PARTS

BRANCH BOX : PAC-MK50BC PAC-MK30BC

Parts name Check points

Disconnect the connector then measure the resistance with a tester.

(At the ambient temperature 10 to 30:)

Normal

4.3 to 9.6k"

Abnormal

Open or short

Linear expansion valve

( LEV-A–E )

M

Red

Blue

Orange

Yellow

White

1

2

3

4

5

Disconnect the connector then measure the resistance with a tester.

(Winding temperature 20:)

Normal

Red - White Red - Orange Red - Yellow Red - Blue

Abnormal

Open or short

46 ± 4"

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15

Linear expansion valve (LEV) in Branch box

(1) Operation summary of the linear expansion valve

• Linear expansion valve open/close through stepping motor after receiving the pulse signal from the branch box controller board.

• Valve position can be changed in proportion to the number of pulse signal.

<Connection between the branch box controller board and the linear expansion valve> branch box controller board

12V DC

LEV

Drive circuit

5

M

1

2

1

4

3

[4

[3

[2

[1

Red 1

Blue

Orange

Yellow

White

2

3

4

5

[4

[3

[2

[1

Connector LEV-A

LEV-B

LEV-C

LEV-D

LEV-E

<Output pulse signal and the valve operation>

Output

(Phase)

[1

[2

[3

[4

1 2 3

Output

4 5 6 7 8

ON ON OFF OFF OFF OFF OFF ON

OFF ON ON ON

OFF OFF OFF OFF

OFF OFF OFF ON ON ON OFF OFF

OFF OFF OFF OFF OFF ON ON ON

Opening a valve : 8 → 7 → 6 → 5 → 4 → 3 → 2 → 1 → 8

Closing a valve : 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 1

The output pulse shifts in above order.

• When linear expansion valve operation stops, all output phases become OFF.

(2) Linear expansion valve operation

Close

Open

C

• When the switch is turned on, 700 pulse closing valve signal will be sent till it goes to

A

point in order to define the valve position.

(The pulse signal is being sent for about 20 seconds.)

• When the valve moves smoothly, there is no sound or vibration occurring from the linear expansion valve : however, when the pulse number moves from

B

to

A

or when the valve is locked, sound can be heard.

No sound is heard when the pulse number moves from

B

to

A

in case coil is burnt out or motor is locked by open-phase.

• Sound can be detected by placing the ear against the screw driver handle while putting the screw driver to the linear expansion valve.

A

B

Pulse number

Extra tightening (about 32 pulse)

500 pulse

Opening a valve all the way

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16

(3) How to attach and detach the coil of linear expansion valve

<Composition>

Linear expansion valve is separable into the main body and the coil as shown in the diagram below.

Coil

Main body

Lead wire

Stopper

<How to detach the coil>

Hold the lower part of the main body (shown as A) firmly so that the main body does not move and detach the coil by pulling it upward.

Be sure to detach the coil holding main body firmly. Otherwise pipes can bend due to pressure.

A

<How to attach the coil>

Hold the lower part of the main body (shown as A) firmly so that the main body does not move and attach the coil by inserting it downward into the main body. Then securely attach the coil stopper to pipe B. (At this time, be careful that stress is not added to lead wire and main body is not wound by lead wire.) If the stopper is not firmly attached to pipe B, coil may be detached from the main body and that can cause defective operation of linear expansion valve.

To prevent piping stress, be sure to attach the coil holding the main body of linear expansion valve firmly. Otherwise pipe may break.

B

A

Be sure to attach the stopper to pipe B.

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17

Troubleshooting

Problem

Locked expansion valve

Check point

If the linear expansion valve becomes locked and the motor is still operating, the motor will emit a clicking noise and will not function. This clicking noise indicates an abnormality.

Corrective measure

Replace the linear expansion valve.

Short circuit or broken circuit in expansion valve motor coil

Use an all-purpose electrical meter to measure the resistance between the different coils (red-white, red-orange, brown-yellow, brown-blue). Normal resistance is within a range of 46" ± 4%.

Valve does not close completely.

Replace the linear expansion valve.

In order to check the linear expansion valve, operate 1 indoor unit in the fan mode and another in the cooling mode. Then, use the outdoor multi controller board to operate the monitor and check the pipe temperature of the indoor unit. The linear expansion valve should be fully closed when the fan is operating. The temperature measured by the temperature sensor will drop if there is any leakage.

If the measured temperature is significantly lower than that on the remote controller, this indicates that the valve is not closed. It is not necessary to replace the linear expansion valve if the leak of refrigerant is small and does not cause a malfunction.

Replace the linear expansion valve if there is a major leak of refrigerant.

Incorrect connection or connection failure

1

Check improperly connected connector terminals and the wire colors.

2

Remove the connector on the controller board side and check electrical

conductance.

Continuity check of wrong part

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7-2. TEST POINT DIAGRAM

Branch box controller board

PAC-MK50BC PAC-MK30BC

TH-A to E Connect to

Thermistor-A to E

TH-D and E for PAC-MK50BC only

LEV-A to E

Connect to LEV-A to E

LEV-D and E for PAC-MK50BC only

CN3M

Connected to the terminal block (TB5)

(M-NET transmission connecting wire)

24–30 V DC (non polar)

LED1,LED2

·Start-up

Main power supply

(220/230/240 V AC)

·Normal operating

LED1:Main power supply

LED2:Blink depend on the total number of indoor units.

<Example>

The total number is 2,

1

Blink 2 times

2

Turn OFF for 3 seconds

3

Repeat 1–2

SW4

Mode selection

SW12

Address setting 10ths DIGIT

SW11

Address setting 1s DIGIT

SW5

Service setting

SW1

Indoor unit connection

F1

Fuse 6.3 A 250 V

CND

Power supply for

Branch box

Controller board

1

–3 220/230/240 V AC

F2,F3,F4

Fuse 10 A 250 V

F4 for PAC-MK50BC only

TB3A to E

Connect to indoor unit TB3D and TB3E for PAC-MK50BC only

1

–3

: Power supply

3

–5

: Transmission

2

–4 220/230/240 V AC 4–6 0–24 V DC

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7-3. INTERNAL SWITCH FUNCTION TABLE

The black square (

■

) indicates a switch position.

1 2

3 4

89

1 2

3 4

89 ON OFF

ON OFF

ON OFF

1 2

3 4

89

1 2

3 4

89

Rotary switch

Ones digit address setting SW12 Tens digit address setting SW1 Indoor unit connection

OCH531A

Fahrenheit temperature

20

1

ON

1 2 3 4 5 6

7-4. BRANCH BOX UNIT OPERATION MONITOR FUNCTION

<Branch box unit operation monitor function>

[When option part ‘A-Control Service Tool (PAC-SK52ST)’ is connected to branch box controller board (CNM)]

Digital indicator LED1 displays 2 digit number or code to inform operation condition and the meaning of check code by controlling DIP SW2 on ‘A-Control Service Tool’.

<Table1> SW5 setting

SW5 setting

ON

Detail

Common

1 2 3 4 5 6

ON

Indoor-A

1 2 3 4 5 6

ON

Indoor-B

1 2 3 4 5 6

ON

Indoor-C

1 2 3 4 5 6

ON

Indoor-D

1 2 3 4 5 6

ON

Indoor-E

1 2 3 4 5 6

The black square (■) indicates a switch position.

Operation indicator:

• SW2 - Use to set the displayed item

• SW5 - Use to set the displayed unit

<Table2> Functions

SW2 setting

SW5 setting*

1

ON

Common

Display detail Explanation for display

Status of branch box

During start-up

The black square (■) indicates a switch position.

Unit

0.5 s 0.5 s

1 2 3 4 5 6

During error detection

Displays a check code, and M-NET address of the unit which the check code was detected.

Example:

If the check code 2520 is detected in the address3,

0.5 s 0.5 s 0.5 s 2.0 s

03

25 20

―

During no power supply

F8

Individual unit Status of branch box

Other

Displays the number of units in operation.

0 to 5

During start-up

0.5 s 0.5 s

During error detection

Displays a check code, and M-NET address of the selected unit.

During no power supply

F8

Other

Displays an operation mode of the selected unit.

0: Stop

C: Cool/ Dry

H: Heat d: Defrost

*

1

Refer to the <Table 1> for the appropriate setting for the function.

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21

―

SW2 setting

ON

1 2 3 4 5 6

SW5 setting*

1

Display detail

Common

Not used

Individual unit Actual opening pulse of LEV

(Direct-operated conversion value)

0 to 500

The black square (■) indicates a switch position.

Explanation for display

―

Unit

―

0 to 500

(When it is 100 pulse or more, it displays a hundredth, tens, and ones digit by turns.)

Example:

When 150 pulse,

0.5 s 0.5 s 2.0 s

1 50

Pulse

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

Common Not used

Individual unit Error history

―

Displays a check code, and M-NET address of the unit which the check code was detected.

Example:

If the check code 2520 is detected in the address3,

0.5 s 0.5 s 0.5 s 2.0 s

03 25

20

―

Code display

Common

The number of unit (s) operating in Thermo-ON

0 to 5

Individual unit Operating status of unit 83: Abnormal

00: Stop

06: Forced stop

0C: Defrost

29: Hot adjust mode

05: Standby mode

2A: Auxiliary heater is ON.

0A: Thermo-ON

01: In operation

Common

The number of indoor unit (s) connected to this branch box.

Individual unit M-NET address

0 to 5

00 to FF

Displays an M-NET address of the selected unit.

Common

Not used

Individual unit Capacity setting in Qj 03 to 50

―

Common Not used

Individual unit Indoor thermistor

<pipe temperature/ liquid> (TH2)

Number

Code display

Number

Code display

―

Code display

―

−39 to 88 [−38 to 190]

(When the temperature is 0: or less, "−" and temperature are displayed by turns.)

―

:

[-

F]*

2 Example:

When −5:,

0.5 s 0.5 s 2.0 s

−

5

* 1

Refer to the <Table 1> for the appropriate setting for the function.

* 2

SW4-1 OFF = :, ON = -F

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SW2 setting

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

SW5 setting*

1

Common

Individual unit

Display detail

Not used

Indoor thermistor

<pipe temperature/

2-phase> (TH5)

The black square (■) indicates a switch position.

Explanation for display

―

Unit

―

−39 to 88 [−38 to 190]

(When the temperature is 0: or less, "−" and temperature are displayed by turns.)

:

[-

F]*

2 Example:

When −5:,

0.5 s 0.5 s 2.0 s

−

5

Common Not used

―

Individual unit Branch box pipe thermistor (TH-A, B, C,

D, E)

−42 to 91 [−43 to 196]

(When the temperature is 0: or less, "−" and temperature are displayed by turns.)

―

:

[-

F]*

2 Example:

When −5:,

0.5 s 0.5 s 2.0 s

−

5

Common

Individual unit

Not used

Indoor thermistor

<room temperature>

(TH1)

Common Not used

Individual unit Set temperature of indoor unit

Common S/W version

8 to 39 [43 to 102]

16 to 31 [61 to 88]

Individual unit

―

―

Displays a S/W version number.

Example:

If it is a ver. 12.34,

0.5 s 0.5 s 2.0 s

12 34

―

:

[-

F]*

2

―

:

[-

F]*

2

Code display

ON

1 2 3 4 5 6

ON

1 2 3 4 5 6

Common

Not used

Individual unit LEV opening pulse

(gear operated value)

0 to 2000

Common

Individual unit

S/W ROM check sum

―

0000 to FFFF

Example:

If it is 0BC9h,

0.5 s 0.5 s 2.0 s

0b

C9

*

1

Refer to the <Table 1> for the appropriate setting for the function.

* 2

SW4-1 OFF = :, ON = -F

―

Pulse

Code display

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8 DISASSEMBLY PROCEDURE

BRANCH BOX : PAC-MK50BC PAC-MK30BC PHOTO : PAC-MK50BC

OPERATING PROCEDURE

1. Removing the controller cover and under panel

(1) Remove 3 controller cover fixing screws (4 o 10) to detach the controller cover. (See Photo 1)

(2) Remove 4 under panel fixing screws (4 o 10) to remove the under panel. (See Photo 1)

PHOTOS

Photo 1

Under panel fixing screws

Under panel

Controller cover

2. Removing the thermistor (TH-A–E*)

(1) Remove the controller cover. (See Photo 1)

(2) Remove the under panel. (See Photo 1)

(3) Remove 8 insulations, then remove 9 pipe box (under) fixing screws (4 o 10). (See Photo 2-1)

(4) Pull out the thermistor(s), TH-A–E, from the sensor holders mounted on the gas pipe. (See Photo 2-2)

(5) Loosen the insulation sheet which bundles the thermistor connectors.

(6) Loosen the side clamps, then disconnect the connector(s) on the controller board.

(7) Pull out the lead wire(s) through the hole to the controller board side.

Photo 2-1

*TH-A–C for PAC-MK30BC. (See Photo 2-3)

Pipe box (under) fixing screws

Screw Insulations

(15 x 15 x 46)

Insulations

(15 x 12 x 45)

Screws

Photo 2-2

Photo 2-3

Header assy

LEV assy

Sensor holder

Sensor holder hole

Insulation sheet

Band

Rubber mount

LEV assy

Header assy

Band

Rubber mount hole Insulation sheet

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24

OPERATING PROCEDURE

3. Removing the LEV coil (LEV-A–E*)

(1) Remove the controller cover. (See Photo 1)

(2) Remove the under cover. (See Photo 1)

(3) Remove 8 insulations, then remove 9 pipe cover fixing screws (4 x 10). (See Photo 2-1)

(4) Cut the bands that fixes the lead wire, then pull out the

LEV coil(s) (LEV-A –E*). (See Photo 3)

(5) Loosen the insulation sheet which bundles the LEV lead wires.

(6) Loosen the side clamps, then disconnect the connector(s) on the controller board.

(7) Pull out the lead wire(s) through the hole to the controller board side.

(See Photo 2-2 or 2-3)

*LEV-A–C for PAC-MK30BC. (See Photo 2-3)

PHOTOS

Photo 3

Rubber mount

Bands

Bands

Header assy

LEV assy

4. Removing the controller board

(1) Remove the controller cover. (See Photo 1)

(2) Loosen the side clamps, then disconnect the connectors on the controller board.

(3) Pick an upper edge of the controller board, then pull forward. The controller board is fixed to the controller board holder with 4 hooks. (See Photo 4)

(4) Remove the controller board from the controller board holder.

Photo 4

Controller board

LEV coil

Controller board holder

Hooks

OCH531A

25

OPERATING PROCEDURE PHOTOS

5. Removing the LEV assy

(1) Remove the controller cover. (See Photo 1)

(2) Remove the under panel. (See Photo 1)

(3) Remove 8 the insulations, then remove 9 pipe cover fixing screws (4 x 10). (See Photo 2-1)

(4) Loosen the side clamps, then disconnect the LEV connectors on the controller board.

(5) Pull out the lead wires through the hole to the controller board side.

<Removing the header assy>

(6) Cut the band which fixes the header assy and LEV assy together, then remove the rubber mount. (See Photo 3)

(7) Remove the header assy. (See Photo 5-1)

Photo 5-1

LEV assy

<Disassembling the pipe box>

(8) Remove 2 side panel fixing screws (4 x 10). (See Photo 5-1)

(9) Pull out the pipe box (top) and separate it from the side panel. (See Photo 5-2)

(10) Turn the pipe box (top) upside down. (See Photo 5-3).

(11) Remove 5 insulations, then remove 5 pipe box (top) fixing screws (4 x 10).

(12) Turn the pipe box (top) upside down again, facing the pipe side up.

(13) Separate the pipe box (center) from the pipe box (top). (See

Photo 5-4.)

(14) Remove the LEV assy.

Photo 5-2

Side panel

<Pipe box cap only for PAC-MK30BC>

The pipe box caps are placed in 2 unused pipe holes between the pipe box top, center and under. (See Photo 5-5)

Side panel fixing screws

Pipe box (top)

Photo 5-3

Insulations (15 x 15 x 35)

Pipe box caps

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Pipe box

(top)

Pipe box (top) fixing screws

OCH531A

27

HEAD OFFICE : TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN c

Copyright 2014 MITSUBISHI ELECTRIC CORPORATION

Distributed in Mar. 2015 No.OCH574 REVISED EDITION-A

Distributed in Sep. 2014 No.OCH574

Made in Japan

New publication, effective Mar. 2015

Specifications are subject to change without notice.