Mitsubishi Electric BRANCH BOX PAC-MKA53BC Operating manual

March 2023

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

TECHNICAL & SERVICE MANUAL

CONTENTS

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

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

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

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

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

. NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION ············

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

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

BRANCH BOX

HFC

utilized

R410A

Note:

• This service manual

describes technical data of

branch box. As for indoor

units and outdoor unit,

refer to its service manual.

PARTS CATALOG (OCB801)

PAC-MKA53BC

No. OCH801

[Service Ref.]

PAC-MKA33BC

PAC-MKA53BC

[Model Name]

PAC-MKA33BC

PAC-MKA53BC

OCH801

1SAFETY PRECAUTION

Cautions for units utilizing refrigerant R410A

1-1. CAUTIONS RELATED TO NEW REFRIGERANT

Use new refrigerant pipes.

Avoid using thin pipes.

Use a vacuum pump with a reverse ow check

valve.

Vacuum pump oil may ow back into refrigerant cycle and

that can cause deterioration of refrigerant oil, etc.

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 refrigera-

nt will change and the e󰀩ciency will be lowered.

Use the specied refrigerant only.

Never use any refrigerant other than that specied.

Doing so may cause a burst, an explosion, or re when

the unit is being used, serviced, or disposed of.

Correct refrigerant is specied 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.

Ventilate the room if refrigerant leaks during

operation. If refrigerant comes into contact with

a ame, poisonous gases will be released.

Use the following tools specically designed for

use with R410A refrigerant.

The following tools are necessary to use R410A

refrigerant.

Tools for R410A

Gauge manifold Flare tool

Charge hose Size adjustment gauge

Gas leak detector Vacuum pump adaptor

Torque wrench Electronic refrigerant

charging scale

Make sure that the inside and outside of refrige-

rant 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 specied thickness.

Contamination inside refrigerant piping can cause deterio-

ration of refrigerant oil, etc.

Store the piping indoors, and keep 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 are and ange

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 e󰀩ciency will be

lowered.

Do not use refrigerant other than R410A.

If other refrigerant (R22, etc.) is used, chlorine in refrige-

rant can cause deterioration of refrigerant oil, etc.

Precautions during the repair service

• Do not perform the work involving the electric parts

with wet hands.

• Do not pour water into the electric parts.

• Do not touch the refrigerant.

•

Do not touch the hot or cold areas in the refrigerating cycle.

• When the repair or the inspection of the circuit needs

to be done without turning o󰀨 the power, exercise great

caution not to touch the live parts.

Preparation before the repair service

• Prepare the proper tools.

• Prepare the proper protectors.

• Provide adequate ventilation.

• After stopping the operation of the air conditioner, turn

o󰀨 the power-supply breaker.

• Discharge the condenser before the work involving the

electric parts.

OCH801

Electronic weighing scale

Unit

[3] Service tools

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

[2] Additional refrigerant charge

When charging directly from cylinder

(1) Check that cylinder for R410A on the market is a syphon type.

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

[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) If moisture or foreign matter might have entered the refrigerant piping during service, ensure to remove them.

No. Tool name Specifications

Gauge manifold · Only for R410A

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

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

Charge hose · Only for R410A

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

Electronic weighing scale

Gas leak detector · Use the detector for R134a, R407C or R410A.

Adaptor for reverse flow check · Attach on vacuum pump.

Refrigerant charge base

Refrigerant cylinder · Only for R410A · Top of cylinder (Pink)

· Cylinder with syphon

Refrigerant recovery equipment

OCH801 4

(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.

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.)

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 its working pressure higher than that of other refriger-

ants. Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been speci-

fied 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.

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

1/4

3/8

1/2

5/8

3/4

ø6.35

ø9.52

ø12.70

ø15.88

ø19.05

0.8

1.0

—

0.8

1.0

Nominal

dimensions (in)

Diagram below: Piping diameter and thickness

Outside

diameter (mm)

Thickness (mm)

R410A R22

1/4

3/8

1/2

5/8

3/4

ø6.35

ø9.52

ø12.70

ø15.88

ø19.05

9.1

13.2

16.6

19.7

—

9.0

13.0

16.2

19.4

23.3

Nominal

dimensions (in)

Flare cutting dimensions

Outside

diameter (mm)

Dimension A ( )

-0.4 (mm)

R410A R22 1/4

3/8

1/2

5/8

3/4

ø6.35

ø9.52

ø12.70

ø15.88

ø19.05

17.0

22.0

26.0

29.0

—

17.0

22.0

24.0

27.0

36.0

Nominal

dimensions (in)

Flare nut dimensions

Outside

diameter (mm

)Dimension B (mm)

R410A R22

Gauge manifold

Charge hose

Gas leak detector

Refrigerant recovery equipment

Refrigerant cylinder

Applied oil

Safety charger

Charge valve

Vacuum pump

Flare tool

Bender

Pipe cutter

Welder and nitrogen gas cylinder

Refrigerant charging scale

Vacuum gauge or thermis-

tor vacuum gauge and

vacuum valve

Charging cylinder

Air purge, refrigerant charge

and operation check

Gas leak check

Refrigerant recovery

Refrigerant charge

Apply to flared section

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 refri-

gerant to thermistor vacuum gauge)

Refrigerant charge

Tool exclusive for R410A

Tool for HFC refrigerant

Tool exclusive for R410A

Ester oil and alkylbenzene

oil (minimum amount)

Tool exclusive for R410A

Tools for other refrigerants can

be used if equipped with adop-

ter 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

Tool exclusive for R410A

Tools and materials Use R410A tools 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)

: 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.

Dimension A

Dimension B

OCH801

2OVERVIEW OF UNIT

Indoor unit (Ceiling concealed type)

Indoor unit

(Wall mounted type)

Outdoor unit Branch box

2-1. SYSTEM OUTLINE

The additional connection of the branch box together with employment of the compact trunk-looking outdoor unit can

successfully realize 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

2-1-2. Method for identifying

Branch box (Controller)

Number of branches

5: 5 branches

3: 3 branches

Model type

P A C – MKA 5 3 BC

(Indispensable)

Optional parts

Development No. : A, B, ···,etc.

Power supply

Single phase 220/230/240 V, 50 Hz

Multi type heat pump

inverter outdoor unit

Indicates equivalent to rated cooling capacity.

(kBTU/h)

Number of connectable indoor units (MAX.)

Control and refrigerant

A : New A control and R410A

M X Y-

100

4 C V A

■ Branch box

OCH801

2-2. INSTALLATION

Space required for Installation and servicing for branch box for PAC-MKA53/33BC

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

Branch box

On the side of piping

(2) Side View (Fig. 2-2, Fig. 2-3, Fig. 2-4)

For indoor installations

Ceiling board

Maintenance hole

Reactor box (Optional parts)

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

*2: is “Min 200 mm”.

In the case of less than 200 mm (for example 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).

To install the optional reactor box, set to Min 270 mm <recommendation>. (Fig. 2-4)

*3: is “□ 600 mm”.

In the case of “□ 450 mm”, prepare a maintenance hole at a PCB side (as it is shown in Fig. 2-3, Fig. 2-4), and “Min 300

mm” is needed as distance .

In the case of less than 300 mm (for example 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. 2-5)

NOTE 1: The branch box is only for indoor use.

NOTE 2: Please attach the special optional cover to install branch box outdoors.

Fig. 2-5

Fig. 2-3

Fig. 2-2Fig. 2-1

Unit: mm

(3)

Min 250

(1) (2)

50 450

�

450

250 250 250

170 30

278

180-200

450

Fig. 2-4

OCH801

Branch box

■ In the case of using 1-branch box

Flare connection employed

2 branches pipe (joint)

: optional parts

Branch box #1

Branch box #2

■ In the case of using 2-branch boxes

■ Installation procedure (2 branches pipe (joint))

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

2-3. SIMPLIFIED PIPING SYSTEM

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

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

If the piping connection size of branch box does not match the piping connection size of outdoor/indoor unit,

use optional different-diameter (deformed) joints to the branch box side.

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

OCH801

3 SPECIFICATIONS

Model name PAC-MKA53BC PAC-MKA33BC

Connectable number of indoor units Maximum 5 Maximum 3

Power supply Single phase, 208/230 V, 60 Hz

Input kW 0.003

Running current A 0.15

External nish Galvanized sheets

Dimensions Width in (mm) 17-23/32 (450)

Depth in (mm) 11-1/32 (280)

Height in (mm) 6-11/16 (170)

Weight lb (kg) 16 (7.4) 15 (6.7)

Piping

connection

(Flare)

Branch (indoor side)* Liquid in (mm) 1/4 (ø6.35) × 5 {A,B,C,D,E} 1/4 (ø6.35) × 3 {A,B,C}

Gas in (mm) 3/8 (ø9.52) × 4 {A,B,C,D}, 1/2 (ø12.7) × 1 {E} 3/8 (ø9.52) × 3 {A,B,C}

Main (outdoor side) Liquid in (mm) 3/8 (ø9.52)

Gas in (mm) 5/8 (ø15.88)

* 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.)

OCH801

4OUTLINES AND DIMENSIONS

Unit: mm(inch)

PAC-MKA33BC

PAC-MKA53BC

TO INDOOR UNIT

AABC B

CAP

〈1〉

〈2-27/32〉

〈3-17/32〉

170〈6-11/16〉

47〈1-27/32〉

〈2-9/16〉

〈1〉

〈2-3/4〉

209〈8-7/32〉

450〈17-23/32〉

SUSPENSION BOLT PITCH

320〈12-19/32〉

402〈15-13/16〉

24〈1〉

12〈1/2〉1/2 inch Conduit

attachment

When installing the conduit.

Set the attachment to the

inner side of each panel.

(1:2)

5-ø22〈7/8〉

〈1-3/32〉

〈25/32〉

58〈2-9/32〉

〈15/16〉

105

〈4-1/8〉

12〈15/32〉

15〈19/32〉

66〈2-19/32〉

〈15/16〉

48〈1-7/8〉48〈1-7/8〉

17〈21/32〉

129〈5-3/32〉

5-ELECTRIC WIRE INLET

CONDUIT PLATE

CONTROL COVER

TO OUTDOOR UNIT

SERV ICE PANEL

(for LEV, THERMISTOR)

40〈1-17/32〉

280〈11-1/32〉

〈3-7/16〉70

〈2-3/4〉

〈3-9/32〉

〈3-25/32〉

112

〈4-3/8〉

TERMINAL BLOCK

TO M-NET UNIT

TERMINAL BLOCK

TO INDOOR UNIT

TERMINAL BLOCK

TO OUTDOOR UNIT

TB2B

TB5

TB3B

TB3CTB3A

SUSPENSION BOLT: W3/8(M10)

GAS PIPE

REFRIGERANT PIPE FLARED CONNECTION

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

3/8F 3/8F 3/8F 5/8F

TO OUTDOOR UNIT

LIQUID PIPE A B C Unit: inch

E D C B A

TO INDOOR UNIT

〈3-17/32〉

〈2-3/4〉

450〈17-23/32〉

67〈2-9/16〉

〈1〉

〈2-9/16〉47〈1-27/32〉

170〈6-11/16〉

〈2-27/32〉

5-ø22〈7/8〉

(1:2)

When installing the conduit.

Set the attachment to the

inner side of each panel.

1/2 inch Conduit

attachment

129〈5-3/32〉

17〈21/32〉48〈1-7/8〉48〈1-7/8〉

〈15/16〉

66〈2-19/32〉

15〈19/32〉

12〈15/32〉105

〈4-1/8〉

〈15/16〉

58〈2-9/32〉

〈25/32〉28

〈1-3/32〉

SUSPENSION BOLT PITCH

320〈12-19/32〉

12〈1/2〉

24〈1〉

402〈15-13/16〉

5-ELECTRIC WIRE INLET

CONDUIT PLATE

CONTROL COVER

SERVICE PANEL

(for LEV, THERMISTOR)

TO OUTDOOR UNIT

40〈1-17/32〉280〈11-1/32〉

〈3-9/32〉

〈3-25/32〉

112

〈4-3/8〉

〈2-3/4〉

〈3-7/16〉

EDCBA

LIQUID PIPE TO OUTDOOR UNIT

5/8F1/2F3/8F3/8F

3/8F

3/8F 3/8F1/4F1/4F1/4F1/4F1/4F

REFRIGERANT PIPE FLARED CONNECTION

GAS PIPE

SUSPENSION BOLT: W3/8(M10)

TB3B TB3D

TB3A TB3C TB3E

TB5 TB2B

TERMINAL BLOCK

TO OUTDOOR UNIT

TERMINAL BLOCK

TO INDOOR UNIT

TERMINAL BLOCK

TO M-NET UNIT

Unit: inch

OCH801

5WIRING DIAGRAM

Other manuals for BRANCH BOX PAC-MKA53BC

This manual suits for next models

Table of contents

Other Mitsubishi Electric Controllers manuals

Mitsubishi Electric

Mitsubishi Electric MELSEC iQ-F Series User manual

Mitsubishi Electric

Mitsubishi Electric LCPU-U-HW Instruction Manual

Mitsubishi Electric

Mitsubishi Electric MELSEC iQ-F FX5 User manual

Mitsubishi Electric

Mitsubishi Electric Procon BAC-IP50 User manual

Mitsubishi Electric

Mitsubishi Electric MELSEC iQ-R Series User manual

Mitsubishi Electric

Mitsubishi Electric MELSEC FX Series User manual

Mitsubishi Electric

Mitsubishi Electric City Multi PAC-LV11M-J User manual

Mitsubishi Electric

Mitsubishi Electric MELSERVO-JET Series User manual

Mitsubishi Electric

Mitsubishi Electric QX10 User manual

Mitsubishi Electric

Mitsubishi Electric CR800 Series User manual

Mitsubishi Electric

Mitsubishi Electric Q Series Owner's manual

Mitsubishi Electric

Mitsubishi Electric MELSEC Q Series User manual

Mitsubishi Electric

Mitsubishi Electric FX3GE-24M series User manual

Mitsubishi Electric

Mitsubishi Electric FX5 MELSEC iQ-F FX5-4LC User manual

Mitsubishi Electric

Mitsubishi Electric QJ71C24N User manual

Mitsubishi Electric

Mitsubishi Electric FX3U-232-BD User manual

Mitsubishi Electric

Mitsubishi Electric MELSEC iQ-F Series Installation guide

Mitsubishi Electric

Mitsubishi Electric PAC-YT51CRB User manual

Mitsubishi Electric

Mitsubishi Electric FX2N-10GM User manual

Mitsubishi Electric

Mitsubishi Electric MELSEC-L User manual

Mitsubishi Electric

Mitsubishi Electric QD77MS User manual

Mitsubishi Electric

Mitsubishi Electric MR-J5D User manual

Mitsubishi Electric

Mitsubishi Electric MELSEC iQ-F Series User manual

Mitsubishi Electric

Mitsubishi Electric Melservo JE Series User manual

Popular Controllers manuals by other brands

Digiplex

Digiplex DGP-848 Programming guide

YASKAWA

YASKAWA SGM series user manual

Sinope

Sinope Calypso RM3500ZB installation guide

Isimet

Isimet DLA Series Style 2 Installation, Operations, Start-up and Maintenance Instructions

LSIS

LSIS sv-ip5a user manual

Rockwell Automation

Rockwell Automation 1769-L31 installation instructions

Airflow

Airflow Uno hab Installation and operating instructions

ABB

ABB ACS580-01 drives Hardware manual

Panasonic

Panasonic GM1 Series Reference manual

Emerson

Emerson SW93 owner's manual

AutoAqua

AutoAqua Smart ATO micro SATO-120P manual

Panasonic

Panasonic FP? Positioning Unit RTEX Technical manual

Samson

Samson Type 5824 Mounting and operating instructions

Alpha IP

Alpha IP MIOB 21001 manual

Siemens

Siemens OpenAir GMA 1 Series Mounting instructions

Surecom

Surecom SR-629 user manual

Fishman

Fishman TriplePlay installation guide

Regulus

Regulus SRS1 T Installation and operation manual