Mitsubishi Electric PAC-MK53BC Operating manual

March 2018
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
TECHNICAL & SERVICE MANUAL
CONTENTS
1. SAFETY PRECAUTION ······································· 2
2. OVERVIEW OF UNIT ··········································· 5
3. SPECIFICATIONS ················································ 9
4. OUTLINES AND DIMENSIONS ···························10
5. WIRING DIAGRAM ············································· 12
6 . NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION············· 13
7. TROUBLESHOOTING ········································ 17
8. DISASSEMBLY PROCEDURE ··························· 26
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 (OCB664)
[Service Ref.]
PAC-MK53BC
PAC-MK53BCB
PAC-MK33BC
PAC-MK33BCB
[Model Name]
<Branch box>
PAC-MK53BC
PAC-MK53BCB
PAC-MK33BC
PAC-MK33BCB
PAC-MK53BC
No. OCH664

2
OCH664
1SAFETY PRECAUTION
Cautions for units utilizing refrigerant R410A
1-1. ALWAYS OBSERVE FOR SAFETY
Use new refrigerant pipes.
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.
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.
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.
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Flare tool
Electronic refrigerant
charging scale
Vacuum pump adaptor
Size adjustment gauge
Gauge manifold
Torque wrench
Gas leak detector
Charge hose
Tools for R410A
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil, etc.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
If large amount of mineral oil enters, that 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.)
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 specified thickness.
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a small amount.
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.
Use the specified refrigerant only. Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
1-2. CAUTIONS RELATED TO NEW REFRIGERANT
Before obtaining access to terminal, all supply
circuit must be disconnected.

3
OCH664
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
1Gaugemanifold
·OnlyforR410A
·Usetheexistingfittingspecifications.(UNF1/2)
·Usehigh-tensionsidepressureof5.3MPa·Gorover.
2Chargehose ·OnlyforR410A
·Usepressureperformanceof5.09MPa·Gorover.
3Electronicweighingscale
4Gasleakdetector ·UsethedetectorforR134a,R407CorR410A.
5Adaptorforreverseflowcheck ·Attachonvacuumpump.
6Refrigerantchargebase
7Refrigerantcylinder ·OnlyforR410A·Topofcylinder(Pink)
·Cylinderwithsyphon
8Refrigerantrecoveryequipment

4
OCH664
(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.)
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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.
3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
6.35
9.52
12.70
15.88
19.05
0.8
0.8
0.8
1.0
—
0.8
0.8
0.8
1.0
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
6.35
9.52
12.70
15.88
19.05
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
-0.4 (mm)
R410A R22 1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
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 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
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
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
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

5
OCH664
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
Model type
Piping connection
B: Brazing
None: Flare
P A C – MK 5 3 BC B
(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

6
OCH664
2-2. INSTALLATION
2-2-1. Space required for Installation and servicing for branch box for PAC-MK53/33BC
(1) Front View (Fig. 2-1)
A Branchbox
B Onthesideofpiping
(2) Side View (Fig. 2-2, Fig. 2-3, Fig. 2-4)
C Forindoorinstallations
D Ceilingboard
E Maintenancehole
F Reactorbox(Optionalparts)
*1: Aminimum350mmisrequiredfor90°bendsinrefrigerantpiping.
*2: Ais“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).
 Toinstalltheoptionalreactorbox,setAtoMin270mm<recommendation>.(Fig.2-4)
*3: Bis“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A.
 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. 2-5)
NOTE1:Thebranchboxisonlyforindooruse.
NOTE2:Pleaseattachthespecialoptionalcover(PAC-AK350CVR-E)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
A
C
B
D E
*1
*3
*2
E D
450
E D
F
Fig. 2-4

7
OCH664
2-2-2. Space required for Installation and servicing for branch box for PAC-MK53/33BCB
(1) Front View (Fig. 2-6)
A Branchbox
B Onthesideofpiping
(2) Side View (Fig. 2-7, Fig. 2-8, Fig. 2-9)
C Forindoorinstallations
D Ceilingboard
E Maintenancehole
*1: Aminimum350mmisrequiredfor90°bendsinrefrigerantpiping.
*2: Ais“Min.200mm”<recommendation>.
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).
 Toinstalltheoptionalreactorbox,setAtoMin.270mm<recommendation>(Fig.2-9)
*3: Bis“600mm”.
 Inthecaseof“450mm”,prepareamaintenanceholeataPCBside(asitisshowninFig.2-8,Fig.2-9),and“Min.300
mm”isneededasdistanceA.
 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. 2-10)
NOTE1:Thebranchboxisonlyforindooruse.
NOTE2:Pleaseattachthespecialoptionalcover(PAC-AK350CVR-E)toinstallbranchboxoutdoors.
Fig. 2-10
Fig. 2-8
Fig. 2-7Fig. 2-6
(3)
Min. 250
(1) (2)
50 450
�450
250
A
B
E D
250 250.3
170 30
278
180-200
C
D
E
*1
*3
*2
Unit: mm
450
Fig. 2-9

8
OCH664
A
B B B B B
Branch box
■Incaseofusing1-branchbox
Flareconnectionemployed
AA
A
B B B B B
2 branches pipe (joint)
: optional parts
Branch box #1
Branch box #2
■Incaseofusing2-branchboxes
■Installationprocedure(2branchpipe(joint))
RefertotheinstallationmanualsofMSDD-50AR-EandMSDD-50BR-E.
2-3. SIMPLIFIED PIPING SYSTEM
Piping connection size
Liquid (mm)
Gas (mm)
{9.52
{15.88
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.)
A B

9
OCH664
3 SPECIFICATIONS
kW
A
mm
mm
mm
kg
mm
mm
mm
mm
Model Name
Connectable number of indoor units
Power supply (from outdoor unit)
Input
Running current
External finish
Dimensions
Weight
Piping
connection
(Flare)
Width
Depth
Height
Branch (indoor side)*
Main (outdoor side)
Liquid
Gas
Liquid
Gas
Maximum 3
6.7
[6.35 O 3 {A,B,C}
[9.52 O 3 {A,B,C}
Maximum 5
7.4
[6.35 O 5 {A,B,C,D,E}
[9.52 O 4 {A,B,C,D}, [12.7 o1{E}
PAC-MK53BC PAC-MK33BC
~/N, 220/230/240 V, 50 Hz, ~/N, 220/230 V, 60 Hz
0.003
0.05 (Max. 6)
Galvanized sheets
450
280
170
[9.52
[15.88
PAC-MK53BC PAC-MK33BC
* 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.)
kW
A
mm
mm
mm
kg
mm
mm
mm
mm
Model Name
Connectable number of indoor units
Power supply (from outdoor unit)
Input
Running current
External finish
Dimensions
Weight
Piping
connection
(Brazing)
Width
Depth
Height
Branch (indoor side)*
Main (outdoor side)
Liquid
Gas
Liquid
Gas
Maximum 3
[6.35 O 3 {A,B,C}
[9.52 O 3 {A,B,C}
Maximum 5
[6.35 O 5 {A,B,C,D,E}
[9.52 O 4 {A,B,C,D}, [12.7 o1{E}
PAC-MK53BCB PAC-MK33BCB
~/N, 220/230/240 V, 50 Hz, ~/N, 220/230 V, 60 Hz
0.003
0.05 (Max. 6)
Galvanized sheets
450
280
170
[9.52
[15.88
7.0 6.5
* 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.)
PAC-MK53BCB PAC-MK33BCB

10
OCH664
4OUTLINES AND DIMENSIONS
Unit: mm
PAC-MK53BC
PAC-MK33BC
{6.35
{9.52
SUSPENSION BOLT : W3/8(M10)
GAS PIPE
REFRIGERANT PIPE BRAZED CONNECTION
{6.35 {9.52
{9.52 {15.88
TO OUTDOOR UNIT
LIQUID PIPE A B C
{9.52
{6.35 DE
{6.35 {6.35
{9.52 {12.7
SUSPENSION BOLT PITCH
SUSPENSION BOLT PITCH
320
12
402
E D C B A
E D C B A
TO INDOOR UNIT
70 70
90450
67 72
7070
2525
252525
65 47
170
5-ELECTRIC WIRE INLET
BUSH
CONTROL COVER
SERVICE PANEL
(for LEV,THERMISTOR)
TO OUTDOOR UNIT
40280
83
96
112
7087
TERMINAL BLOCK
TO M-NET UNIT
TERMINAL BLOCK
TO INDOOR UNIT
TERMINAL BLOCK
TO OUTDOOR UNIT
TB2B
TB5
TB3ETB3CTB3A
TB3DTB3B
24
CAP
CAP
C B
CBA
A
TO INDOOR UNIT
450
70
70
25
65 47
170
209
2525
90
72 5-ELECTRIC WIRE INLET
BUSH
CONTROL COVER
TO OUTDOOR UNIT
SERVICE PANEL
(for LEV.THERMISTOR)
83
96 40 280
87 70
112
TB3A TB3C
TB3B
TB5 TB2B
TERMINAL BLOCK
TO OUTDOOR UNIT
TERMINAL BLOCK
TO INDOOR UNIT
TERMINAL BLOCK
TO M-NET UNIT
SUSPENSION BOLT PITCH
SUSPENSION BOLT PITCH
12
402
320
24
{6.35
{9.52
SUSPENSION BOLT : W3/8(M10)
GAS PIPE
REFRIGERANT PIPE BRAZED CONNECTION
{ 6.35 { 9.52
{9.52 {15.88
TO OUTDOOR UNIT
LIQUID PIPE A B C
{9.52
{6.35

11
OCH664
Unit: mm
PAC-MK53BCB
PAC-MK33BCB
SUSPENSION BOLT PITCH
SUSPENSION BOLT PITCH
320
402
24
12
TERMINAL BLOCK
TO M-NET UNIT
TERMINAL BLOCK
TO INDOOR UNIT
TERMINAL BLOCK
TO OUTDOOR UNIT
TB3B
TB3A TB3C
TB5 TB2B
119
AA BBC C
CAP
CAP TO INDOOR UNIT
209
170
119450
4765
25
70
25
70
25
5-ELECTRIC WIRE INLET
BUSH
CONTROL COVER
TO OUTDOOR UNIT
SERVICE PANEL
(for LEV.THERMISTOR)
87 70
280 40
112
113
{6.35
{9.52
SUSPENSION BOLT : W3/8(M10)
GAS PIPE
REFRIGERANT PIPE BRAZED CONNECTION
{ 6.35 { 9.52
{9.52 {15.88
TO OUTDOOR UNIT
LIQUID PIPE A B C
{9.52
{6.35
TO INDOOR UNIT
EEDDCCBBAA
170
450 119
67
4765
25 25 25 25 25
70 70 70 70
SUSPENSION BOLT PITCH
SUSPENSION BOLT PITCH
12
24
402
320
TB3B TB3D
TB3A TB3C TB3E
TB5 TB2B
TERMINAL BLOCK
TO OUTDOOR UNIT
TERMINAL BLOCK
TO INDOOR UNIT
TERMINAL BLOCK
TO M-NET UNIT
119
TO OUTDOOR UNIT
SERVICE PANEL
(for LEV,THERMISTOR)
CONTROL COVER
BUSH
5-ELECTRIC WIRE INLET
112
113 40280
87 70
{6.35
{9.52
SUSPENSION BOLT : W3/8(M10)
GAS PIPE
REFRIGERANT PIPE BRAZED CONNECTION
{6.35 {9.52
{9.52 {15.88
TO OUTDOOR UNIT
LIQUID PIPE A B C
{9.52
{6.35 DE
{6.35 {6.35
{9.52 {12.7

12
OCH664
5WIRING DIAGRAM
PAC-MK53BC PAC-MK33BC
PAC-MK53BCB PAC-MK33BCB
<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.
However, when the Branch box is
connected to MXZ-6C/8C∙NAM,
power must not be supplied separately.
3. For the connection method, please
refer to the Branch box Installation
Manual.
<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.
SYMBOL
B.C.
LEV-A~E
TH-A~E
TB2B
TB5
REACTOR BOX
F1
F2~F4
SW1
SW4
SW5
CNM
LED1,2
TB3A~E
SW11
SW12
TB2C
TB2D
Branch box controller board
Fuse <T6.3AL 250V>
Fuse <T10AL 250V> *1
Switch for indoor unit connection *2
Switch for function selection *3
Switch for function selection *4
Connector <Connection for service>
Light emitting diode *5
Terminal block <To Indoor unit-A~E> *6
Address Setting ones digit
Address Setting tens digit
Linear expansion valve *6
Thermistor <Gas pipe> *6
Terminal block <To Power Supply>
Transmission line
Optional parts
Terminal block <To Power Supply>
Terminal block <To Branch box (TB2B)>
NAME
Indoor unit-A Indoor unit-B Indoor unit-C Indoor unit-D Indoor unit-E
<Symbols used in wiring diagram>
:Terminal block, : Connector
: Dip switch (■ (black square)
indicates a switch position)
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.
*3
SW 4 setting
When the outdoor unit is cooling only system, turn
SW4-5 to on.
*4 Refer to the installation manual of Branch box for details.
*5 LED on Branch box controller board for service
*6 D and E for PAC-MK53BC (B) only
•start-up
Mark
LED 1
LED 2 Main power supply
Meaning Main power supply
(220/230/240V)
Power on →Lamps are lit
Function
Mark
LED 2 Total number of
indoor units
Meaning
Blink depend on the total number
<example> The total number is 2
1 Blink
2 times.
2 Turn off for 3 sec.
3 Repeat
1 to 2 .
LED 1 Main power supply Lamp is lit Function
• normal operating
PAC-MK
53BC (B)
only
BU BU
BK
WH
RD
BU
BK
WH
TO OUTDOOR UNIT
LEV-E
LEV-D
LEV-C
LEV-B
LEV-A
TH-E tº
TH-D tº
TH-C tº
TH-B tº
TH-A tº
1 2 3 4 5 6
SW5
ON
OFF
10s
DIGIT 1s DIGIT
TO
INDOOR
UNIT-E
TO
INDOOR
UNIT-D
TO
INDOOR
UNIT-C
TO
INDOOR
UNIT-B
TO
INDOOR
UNIT-A
L
N
S3
S2
S1
S3
S2
S1
S3
S2
S1
S3
S2
S1
S3
S2
S1
M1
M2
S
TO OUTDOOR UNIT
DC24-30V
TB3E
TB3C
TB3A
TB3D
TB3B
TB1
F4
10A250V
F3
10A250V
F2
10A250V
TB2B L
N
L
N
TB5
(SHIELD)
(SHIELD)
CND
(BK)
F1
6.3A250V
+–
3
1
5
LEV-E
(GN)
1
5
LEV-D
(BK)
1
5
LEV-C
(BU)
1
5
LEV-B
(RD)
1
5
LEV-A
(WH)
1
2 TH-E
1 (GN)
2 TH-D
1 (BK)
2 TH-C
1 (BU)
2 TH-B
1 (RD)
2 TH-A
1 (WH)
M
M
M
M
M
(PAC-MK53BC (B) only)
(PAC-MK53BC (B) only)
0
1
2
3
4
5
6
7
8
9
SW12
0
1
2
3
4
5
6
7
8
9
SW11
ON
OFF
1 2 3 4 5 6 78 9 10
SW4 *3
1 2 3 4 5 6
SW1 *2
ON
OFF
LED1
LED2 CNM
(WH)
114
INDOOR UNIT-A
INDOOR UNIT-B
INDOOR UNIT-C
INDOOR UNIT-D
INDOOR UNIT-E
NO USE
SW1-1
SW1-2
SW1-3
SW1-4
SW1-5
SW1-6
NOT CONNECT
NOT CONNECT
NOT CONNECT
NOT CONNECT
NOT CONNECT
CONNECT
CONNECT
CONNECT
CONNECT
CONNECT
*
1 F4 for PAC-MK53BC (B) only
*
2 SW1 setting
OFF ON
Cooling & Heating system
SW4-5 Cooling only system
OFF ON
B.C.
BU
BU
(PAC-MK53BC (B) only)
TO ANOTHER
BRANCH BOX
TO ANOTHER BRANCH BOX or
M-NET CONTROL INDOOR UNIT
POWER SUPPLY
220/230/240V 50Hz
220/230V 60Hz
L
N
TB2B
TO ANOTHER
BRANCH BOX,
REACTOR BOX
(optional parts)
*
7
or M-NET
CONTROL
INDOOR UNIT
CIRCUIT
BREAKER
Fig. 1
PULL
BOX
M-NET
CN3M
(BU)
1
3
PULL
BOX
REACTOR BOX (optional parts)*7
L
N
L
N
*
7 Depending on which
indoor unit is combined
with which outdoor unit,
reactor box should be
installed.
Refer to the installation
manual of branch box or
that of outdoor unit for
details.
REACTOR BOX
(optional parts)*7
TB2D TB2C
TB2D TB2C

13
OCH664
6 NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION
6-1. TRANSMISSION SYSTEM SETUP
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
2
Branch box
001 Branch box
006
A-control
Indoor unit
A
(001)
A-control
Indoor unit
B
(002) C
(003)
A-control
Indoor unit
A
(006) B
(007) C
(008)
D
(004) E
(005)
M-NET cable
①M-NET cable shielding wire must
be connected to each refrigerant
system (outdoorand branch box).
②Set addresses :
Outdoor unit ............051–100
Branch box ............... 001–046
③Outdoor unit has no 100s digit switch.
The address automatically become "100"
if it is set as "01–50".
Piping
Signal line
④Make sure that the wiring between the
branch box and indoor unit is properly done, matching with the piping connection.
A B C D E A B C
MA remote
controller MA remote
controller MA remote
controller MA remote
controller
WL-RC WL-RC
WL-RC
WL-RC
For centralized management 051
Outdoor unit Piping
For Branch box/ City Multi indoor unit
1
4
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW 0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW 0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
SW1
ON
123456
SW1
ON
123456
City Multi
Indoor unit
009
City Multi
Indoor unit
010
MA remote
controller
City Multi .................. 001–050
For centralized management
061
Outdoor unit
For Branch box/ City Multi indoor unit
0
1
2
3
4
5
6
7
8
9
Address SW City Multi
Indoor unit
011
City Multi
Indoor unit
012
City Multi
Indoor unit
013
City Multi
Indoor unit
014
City Multi
Indoor unit
015
114 164
MA remote
controller
M-NET
remote
controller
M-NET
remote
controller
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
Address SW
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
⑤M-NET remote controller cannot be connected with a refrigerant system which includes branch box.
5
A-control
Indoor unit A-control
Indoor unit A-control
Indoor unit A-control
Indoor unit A-control
Indoor unit
⑥The refrigerant system which includes branch box cannot be operated as a group by M-NET remote controller or system controller.

14
OCH664
Capillary
tube Capillary tube
E
D
C
B
A
Strainer
#100
Strainer
#100
Thermistor (TH-A–E)
(Gas pipe temperature)
LEV A–E
(Linear expansion valve)
C
B
A
Strainer
#100
Strainer
#100
Thermistor (TH-A–C)
(Gas pipe temperature)
LEV A–C
(Linear expansion valve)
PAC-MK53BC(B)
PAC-MK33BC(B)
Branch box
Capillary tube behind LEV
(in cooling mode)
([4 o[3.0 oL130) o5
([4 o[3.0 oL130) o3
Unit: mm
■PAC-MK53BC PAC-MK53BCB ■PAC-MK33BC PAC-MK33BCB
6-2. REFRIGERANT SYSTEM DIAGRAM

15
OCH664
6-3. TYPICAL CONTROL SYSTEM
TB7
TB3
(51)
L5
L1
OC
TB7
(53)
OC
24 V DC
L6
L7
M1M2
S
M1M2
S
S
M1M2
S
TB3
M1M2
S
M1M2
S
M1M2
TB3A A-IC
(01)
A-IC
(02)
A-IC
(03)
A-IC
(04)
A-IC
MA-RC
MA-RC
MA-RC
MA-RC
WL-RC
WL-RC
WL-RC
WL-RC
(05)
A-IC
(06)
A-IC
(07)
A-IC
(08)
S1
S2
S3
TB
S1
S2
TB5/TB15
1
2A B
A
B
A
B
A
B
TB5/TB15
1
2
TB5/TB15
1
2
TB5/TB15
1
2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB
S1
S2
S3
TB3B
S1
S2
S3
TB3C
S1
S2
S3
TB3D
S1
S2
S3
TB3E
S1
S2
S3
TB3A
S1
S2
S3
TB3B
S1
S2
S3
TB3C
S1
S2
S3
M1
M2
S
TB5
M1
M2
S
TB5
L2
A
A
A
M-IC
(09)
M-IC
(10)
MA-RC
MA-RC
TB5
M1
M2
TB15
1
2A B
A
B
TB15
1
2
S
TB5
M1
M2
S
L3
L4
Power
Supply
Unit
System
controller
Branch Box
Branch Box
A: Shielded wire
( ): Address example
Note:M-NETremotecontrollercannotbeconnectedwitharefrigerantsystemwhichincludesbranchbox.
(1) Difference between display and operation
1 Whenoperatingthesystemusingthesystem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system
controller.Theroomairconditionerhasawiderrange.Ifthetargettemperatureissettobelow17:orless,or30:or
morebythewirelessremotecontrollerthatcomeswithroomairconditioner,thetemperaturedisplayedonthesystem
controllermaybeconvertedtotheirmaximum/minimumsettemperature.Forinstance,whenHEAToperationat16:isset
attheroomairconditioner,thesystemcontrollermaydisplay17:.
3 WhentheDRYmodeissetwiththewirelessremotecontroller,theroomairconditionerautomaticallysettheoptimum
targettemperature.Thesystemcontrollerwilldisplaythetargettemperatureasasettemperature.
4WhentheDRYmodeissetwiththesystemcontroller,theroomairconditionerperformstheDRYmodecontroloperation
accordingtothetemperature setwiththesystemcontroller.
(2) Timer operation
1Timeroperationshouldbesetusingonly1controllerfromtheremotecontrollerthatcomeswiththeroomairconditioner,
thesystemcontrollerortheMAremotecontroller.Ifmorethan1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systemcontrollerwillnotshowthetimerdisplay.
3Thetimersetwith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,3shortbeepswillsoundwhenthesignalissent
fromthewirelessremotecontroller.
(4) Trouble
1IftheMAremotecontrollerorthesystemcontrollershowstheabnormalindication,clearitbystoppingtheoperationwith
oneofthefollowing:theMA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orthe
systemcontrollercannotberecoveredunlesstheoperationisstopped.)
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 +L6 + L7 500 m (1640 ft) (1.25 mm² or more)
Longest transmission cable length
L1+ L2+ L3+ L4, L5 + L6, L7200 m (656 ft) (1.25 mm² or more)
OC:Outdoorunit
M-IC:M-NETControlindoorunit(CityMultiindoorunit)
A-IC:A-controlindoorunit
MA-RC:MARemotecontroller
WL-RC:WirelessRemotecontroller

16
OCH664
(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
•Cylinderunitorhydroboxcannotbeoperatedfromsystemcontroller.

17
OCH664
7 TROUBLESHOOTING
7-1. HOW TO CHECK THE PARTS
BRANCH BOX : PAC-MK53BC PAC-MK33BC
PAC-MK53BCB PAC-MK33BCB
Partsname Checkpoints
Thermistor(TH-A–E)
<Gaspipe>
Disconnecttheconnectorthenmeasuretheresistancewithatester.
(Attheambienttemperature10to30°C)
ThermistorR0=15k" ± 3%
FixednumberofB=3480 ± 2%
Rt=15exp{3480()}
 10: 9.7k"
 15: 7.9k"
 20: 6.4k"
 25: 5.3k"
 30: 4.4k"
< Thermistor for lower temperature >
Temperature (:)
Resistance (k")
10 15 20 25 30
0
2
4
6
8
10
12
Linearexpansionvalve
(LEV-A–E)
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
1
2
3
4
5
MBlue
Yellow
Orange
Red
White
Disconnecttheconnectorthenmeasuretheresistancewithatester.
(Windingtemperature20°C)
Normal Abnormal
Red-White Red-Orange Red-Yellow Red-Blue Openorshort
46±4Ω
1
273+t
1
273

18
OCH664
<Output pulse signal and the valve operation>
(2) Linear expansion valve operation
A
B
Open
Extra tightening (about 32 pulse)
Pulse number
500 pulse
Opening a valve
all the way
Close
Valve position (capacity)
Close
Open
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.
•Whenthepower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Bto Aorwhenthevalveislocked,soundcan
beheard.
 NosoundisheardwhenthepulsenumbermovesfromBto 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.
Linearexpansionvalve
(1) Operation summary of the linear expansion valve
•Linearexpansionvalveopens/closes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>
1
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
[1
Output
(Phase)
Output
[2
[3
[4
2 3 4 5 6 7 8
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
ON
(LEV)inBranchbox
LEV
M
1
5
[4
[4
[3
[2
[1
1
Red
Blue
Orange
Yellow
White
2
3
4
5
Connector LEV-A
LEV-B
LEV-C
LEV-D
LEV-E
12 V DC
branch box controller board
Drive circuit
[3
[2
[1
2
1
4
3

19
OCH664
Main body
Lead wire Stopper
Coil
(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.
A
<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stress.
Be sure to attach the
stopper to pipe B.
BA
<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stop-
per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expan-
sionvalve.
Topreventpipingstress,besuretoattachthecoilholdingthe
mainbodyoflinearexpansionvalvefirmly.Otherwisepipemay
break.

20
OCH664
Troubleshooting
Problem Check point Corrective measure
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.
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%.
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.
1Check improperly connected connector terminals and the wire colors.
2Remove the connector on the controller board side and check electrical
conductance.
Locked expansion
valve
Short circuit or broken
circuit in expansion
valve motor coil
Valve does not close
completely.
Incorrect connection
or connection failure
Replace the linear
expansion valve.
Replace the linear
expansion valve.
Replace the linear
expansion valve if there
is a major leak of
refrigerant.
Continuity check of
wrong part