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