Mitsubishi Electric MSZ-CA25VB User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································5
4. NOISE CRITERIA CURVES·······························6
5. OUTLINES AND DIMENSIONS ·························7
6. WIRING DIAGRAM ············································8
7. REFRIGERANT SYSTEM DIAGRAM················8
8. SERVICE FUNCTIONS ······································9
9. TROUBLESHOOTING······································11
10. DISASSEMBLY INSTRUCTIONS·····················22
11. PARTS LIST······················································24
Wireless type
Models
MSZ-CA25VB - (WH)
MSZ-CA35VB - (WH)
E1
E1
No. OB390
SPLIT-TYPE, HEAT PUMPAIR CONDITIONERS
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
NOTE:
This service manual describes technical data of the indoor units.
•As for outdoor units MUZ-CA25VB- and MUZ-CA35VB- , refer to the service manual
OB391.
•As for outdoor units MXZ-A14WV- and MXZ-A18WV- , refer to the service manual
OB319. E1E1
E1E1
Indication of
model name
OB390--1qxp 05.2.9 11:27 Page 1

2
1TECHNICAL CHANGE
MSZ-A09YV - ➔MSZ-CA25VB -
MSZ-A12YV - ➔MSZ-CA35VB - E1E1
E1E1
1. Indication of capacity has been changed.(BTU➔kW)
2. Shape of front panel has been changed.(Dimension has been changed)
3. Indoor electronic control P.C. board has been changed.
OB390--1qxp 05.2.9 11:27 Page 2

3
2PART NAMES AND FUNCTIONS
ACCESSORIES
1
2
3
4
5
6
7
8
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 33.5 o1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Air cleaning filter
MSZ-CA25VB - E1
MSZ-CA35VB - E1
1
7
1
2
2
1
1
2
INDOOR UNIT
INDOOR UNIT
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
Emergency operation switch
Operation section
Horizontal vane
Air filter
Air outlet
Vertical vane
Air inlet
to Breaker
Remote control
receiving section
Remote controller
Display section
(When the front panel is opened)
Operation indicator lamp
Receiving section
Air cleaning filter
(White bellows type)
Power supply cord
Panel
Front panel
OB390--1qxp 05.2.9 11:27 Page 3

4
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
AMPM
CLOCK
˚C
AM
RESET CLOCK
I FEEL
COOL
DRY
AUTO
HEAT
Open the front lid.
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF) button
TEMPERATURE buttons
OPERATION SELECT button
FAN SPEED CONTROL button
OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
ECONO COOL button
VANE CONTROL button
CLOCK SET button
Indication of remote controller model
(back side)
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
OB390--1qxp 05.2.9 11:27 Page 4

5
1.5+ 440V
250V 3.15A
93:5A 250V
MSBPC20 12V 250"
ERZV10D471
S201DH1Y
5P
JM1aN-ZTMP-DC12V
136:i3: 2A
INDOOR UNIT
Item Model
Indoor fan capacitor
Fuse
Thermal fuse
Vane motor
Varistor
Solid state relay
Terminal block
Contactor
Indoor fan motor thermal fuse
MSZ-CA25VB - E1 MSZ-CA35VB - E1
(C11)
(F11)
(F12)
(MV)
(NR11)
(SR141)
(TB)
(52C)
Specifications and rating conditions of main electric parts
3SPECIFICATION
MSZ-CA25VB - E1 MSZ-CA35VB - E1
Indoor model
Function
Power supply Single phase
230V,50Hz
10
0.17
35
—
0.17
RC4V19-LA
WHT-BLK 413
BLK-RED 334
815O278O217
9
5
3
10
10
10
KM04G
Cooling
504/360
W /222 W
88
37/29 W /21 W
930/730 W /530 W
Heating
564/402
W /246 W
94
38/30 W /21 W
1,020/790 W /570 W
Single phase
230V,50Hz
10
0.19
40
—
0.19
RC4V19-KA
WHT-BLK 316
BLK-RED 299
815O278O217
10
5
3
10
10
10
KM04G
Cooling
630/462
W /288 W
95
39/31 W /22 W
990/780 W /560 W
Heating
642/474 W /312 W
94
38/30
W /22 W
1,000/790 W /590 W
Air flow (High/Med.W/LowW)
Power outlet
Running current ✽1
Power input ✽1
Auxiliary heater
Power factor ✽1
Fan motor current ✽1
Model
Winding
resistance(at20:)
Dimensions WOHOD
Weight
Air direction
Sound level (High/Med.W/LowW)
Fan speed(High/Med.W/LowW)
Fan speed regulator
Thermistor RT11(at25:)
Thermistor RT12(at25:)
Thermistor RT13(at25:)
Remote controller model
K/h
A
A
W
A(kW)
%
A
"
mm
kg
dB(A)
rpm
k"
k"
k"
Electrical data
Fan motor
Special remarks
Capacity
NOTE : Test conditions are based on ISO 5151
Cooling : Indoor DB27:WB19:
Outdoor DB35:WB 24:
Heating : Indoor DB 20:WB15:
Outdoor DB 7:WB 6:
Refrigerant piping length (one way): 5m
wReference value
✽1 Measured under rated operating frequency.
OB390--1qxp 05.2.9 11:27 Page 5

6
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
COOLING
FUNCTION
37
38
SPL(dB(A)) LINE
High
FAN SPEED
HEATING
Heating : Dry-bulb temperature 20: Wet-bulb temperature 15:
MSZ-CA25VB - E1
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
COOLING
FUNCTION
39
38
SPL(dB(A)) LINE
High
FAN SPEED
HEATING
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
Heating : Dry-bulb temperature 20: Wet-bulb temperature 15:
INDOORUNIT WALL
MICROPHONE
0.8m
1m
MSZ-CA35VB - E1
OB390--1qxp 05.2.9 11:27 Page 6

7
5OUTLINES AND DIMENSIONS
MSZ-CA25VB - E1
MSC-CA35VB - E1
INDOOR UNIT
INDOOR UNIT
217
215
81.5
81.5
41
2.5
42
271
231.5
4.5
81.5 133.5
326326
159
19
58
5
7 or more
90
110
30
149
606
278
60
815
783
Wall hole [65
Indoor unit
Installation plate
Installation plate
Insulation [28
Drain hose [16
(Connected part O.D)
Air in
Air out
Power supply cord
Lead to right 1.0m
Lead to left 0.3m
Wireless remote controller
Liquid line [6.35-0.5m
Gas line [9.52-0.43m
Insulation [37 O.D
[21 I.D
{
217
215
218.5
258
81.581.5
41
42
2.5
17.5
161.5
161.5
326326
159
19
58
5
7 or more
90
110
30
149
606
278
60
815
783 Indoor unit
Installation plate
Wall hole [65
Installation plate
Insulation [28
Drain hose [16
(Connected part O.D)
Air in
Air out
Power supply cord
Lead to right 1.0m
Lead to left 0.3m
Wireless remote controller
Liquid line [6.35-0.5m
Gas line [9.52-0.43m
Insulation [37 O.D
[21 I.D
{
Unit: mm
OB390--1qxp 05.2.9 11:27 Page 7

8
WIRING DIAGRAM
6
REFRIGERANT SYSTEM DIAGRAM
7
MSZ-CA25VB - E1
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Flared connection
Refrigerant flow in cooling
Refrigerant flow in heating
Refrigerant pipe [9.52
(with heat insulator)
Refrigerant pipe
[6.35
(with heat insulator)
Indoor coil
thermistor
RT12(main)
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Flared connection
Refrigerant pipe [9.52
(with heat insulator)
Refrigerant pipe
[6.35
(with heat insulator)
Indoor coil
thermistor
RT12(main)
INDOOR UNIT
Unit:mm
INDOOR UNIT MODELS WIRING DIAGRAM
SYMBOL
C11
F11
F12
MF
MV
SYMBOL
NR11
RT11
RT12
RT13
SR141
SYMBOL
SR142
T11
TB
52C
NAME
INDOOR FAN CAPACITOR
FUSE (3.15A)
THERMAL FUSE (93:)
INDOOR FAN MOTOR (INNER FUSE)
VANE MOTOR
NAME
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR (MAIN)
INDOOR COIL THERMISTOR (SUB)
SOLID STATE RELAY
NAME
SOLID STATE RELAY
TRANSFORMER
TERMINAL BLOCK
CONTACTOR
GRN/YLW
BLK
GRY
YLW
BRN
WHT
RED
MF
1
2
3
4
5
6
3
SR141 SR142
5
3
1
C11
RT13
RT12
CN
112
CN
111
CN
121
151
CN
109
CN
125
CN
1R1
CN
MV
5 2 3 2
5
RT11
CN211
NR11
ELECTRONIC CONTROL P.C. BOARD
F11
T11
230V~
BRN
BRN
TB
L
3
N
2
RED
WHT
BLU F12 BLU
BLU 1
2BLU 1
2
3
CN201 3
4
52C
12V
TO OUTDOOR
UNIT
CONNECTING
L
3
N
2
12V
TO OUTDOOR
FOR MXZ type
UNIT
CONNECTING REMOTE
CONTROLLER
POWER MONITOR
RECEIVER
SAFETY
DEVICE (FAN)
P.C. BOARD
LD103
GRN
CIRCUIT BREAKER
POWER
SUPPLY
CORD
~/N 230V
50Hz
PE
BLU
GRN/YLW
NOTE:1. About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2. Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
MSZ-CA35VB - E1
INDOOR UNIT
OB390--1qxp 05.2.9 11:27 Page 8

9
8SERVICE FUNCTIONS
8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be
modified according to the number of the indoor unit.
8-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to 9-7.)
Set time : 1-minute ➔ 1-second
Set time : 3-minute ➔ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by short circuit of JPG and JPS.)
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
No. 1 unit
No. 2 unit
No. 3 unit
No. 4 unit
1 unit operation
No modification
–
–
–
2 units operation
Same as at left
Solder J1
–
–
3 units operation
Same as at left
Same as at left
Solder J2
–
4 units operation
Same as at left
Same as at left
Same as at left
Solder both J1 and J2
Table 1
How to set the remote controller exclusively for particular indoor unit.
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote
controller for the indoor unit.
The indoor unit will only accepts the signal from the remote controller that has been assigned to the indoor unit once they are
set.
The setting will be cancelled if the breaker has turned off, or the power supply has shut down.
Please conduct the above setting once again after the power has restored.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below :
The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table
1.
After modification, press RESET button.
NOTE : For remodelling, take out
the batteries and press
OPERATE/STOP(ON/OFF)
button twice or 3 times at
first.
After finish remodelling,
put back the batteries then
press RESET button.
Remote controller model : KM04G
J2
J1
8-3. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed
are memorized by the indoor electronic control P.C. board. The “AUTO RESTART FUNCTION” sets to work the moment
power has restored after power failure. Then, the unit will restart automatically.
However if the unit is operated in “I FEEL CONTROL” mode before power failure,
the operation is not memorized. In “I FEEL CONTROL” mode, the operation is decided by the initial room temperature.
OB390--1qxp 05.2.9 11:27 Page 9

10
NOTE:
• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote
controller.
• If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is can-
celled.
• If the unit has been off with the remote controller before power failure, the auto restart function does not works as the
power button of the remote controller is off.
• To prevent breaker off due to the rush of starting current, systematize other home appliance not to turn on at the same
time.
• When some air conditioners are connected to the same supply system, if they are operated before power failure, the
starting current of all the compressors may flow simultaneously at restart.
Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current
by adding to the system that allows the units to start one by one.
Operation
1If the main power has been cut, the operation settings remain.
2After the power is restored, the unit restarts automatically according to the memory. (However, it takes at least 3 minutes
for the compressor to start running.)
How to release “AUTO RESTART FUNCTION”
1Turn off the main power for the unit.
2Pull out the indoor electronic control P.C. board and the power monitor receiver P.C.board. (Refer to 10-1.2.)
3Solder the Jumper wire to JR07 on the indoor electronic control P.C.board. (Refer to 9-7.)
JR07
IC101
CN151
SW1
CN112
CN111
CN201
52C
C11
CN211
CN1V1
CN1R1CN121
OB390--1qxp 05.2.9 11:27 Page 10

11
9TROUBLESHOOTING
3. Troubleshooting procedure
1) First, check if OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) When troubleshooting, refer to 9-2.,9-3. and 9-4.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
RESET button
9-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the
electronic control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
Housing point
Lead wiring
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.
NOTE : 1. If RESET button is not pressed, the remote controller may not operate correctly.
2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by
the battery replacement.
2Press RESET button with tip end of ball point
pen or the like, and then use the remote controller.
1Remove the front lid and insert batteries.
Then reattach the front lid.
MSZ-CA25VB -
MSZ-CA35VB - E1
E1
OB390--1qxp 05.2.9 11:27 Page 11

12
5. How to install the horizontal vanes
Upper vane
Lower vane
In procedures 2,3,5, and 6, lock the stoppers until they click into place.
6 5 4
3 2 1
If horizontal vanes are not installed correctly, both of the operation indicator lamps will blink.
In this case, install the horizontal vanes correctly by following the procedures 1to 6.
NOTE: Before installation of the horizontal vanes, disconnect the power supply plug and/ or turn off the breaker.
The holes on the
insertion ends of
the upper and lower
horizontal vanes
different shapes.
Insert this end first.
Upper right
Lower right
Insert this end first.
Stopper
Lock.
Stopper
Lock.
Lock. Lock. In. Insert.
Insert.
In.
INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT : MXZ series
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
•Unit won’t operate in case the total capacity of indoor units exceeds the capacity of outdoor units. Do not
connect indoor units beyond the outdoor unit capacity.
•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and
the other for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor
units will start the operation later cannot operate, indicating as shown in the figure below. In this case, please
set all the indoor units to the same operation mode.
•When indoor units starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes
(max. 10 minutes) to blow out the warm air.
•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant
flowing may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
Lighted
Blinking
Operation Indicator
OB390--1qxp 05.2.9 11:27 Page 12

13
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though OPERATION INDICATOR lamp indication listed on the troubleshooting check (9-4.) table disappears, the
memorized failure details can be recalled.
This model is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
9-2. Failure mode recall function
1. Flow chart of the indoor/outdoor unit failure mode recall function
Operational procedure
Releasing the failure mode recall function
Note1.Make sure to release the failure mode recall function once it's set up, otherwise the unit cannot operate properly.
2.If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
3.In case the right lamp of OPERATION INDICATOR lamp is blinking, the indoor unit and outdoor unit are commuicating normally.
If its lighting or not lighting, they are not normally communicating.
The cause of abnormality cannot be found because the abnormality doesn't recur.
Setting up the failure mode recall function
Turn ON the power supply.
1While pressing both OPERATION SELECT button and TOO COOL
button on the remote controller at the same time, press RESET button.
2First, release RESET button.
And release the other two buttons since all LCD in operation display
section of the remote controller is displayed after 3 seconds.
Deleting the abnormal condition
1After repairing the unit, recall the failure mode again according to
"Setting up the failure mode recall function" mentioned above.
2Press EMERGENCY OPERATION switch so that the memorized
abnormal condition is deleted.
3Release the failure mode recall function according to "Releasing the
failure mode recall function" mentioned above.
Repair the defective parts.
Release the failure mode recall function by the following procedures.
1With the remote controller headed towards the indoor unit, press any button
that is not used in this failure mode recall function (e.g. TIMER button) .
OR
1Turn OFF the power supply of the indoor unit and turn ON it again.
2Press RESET button of the remote controller.
Press OPERATE/STOP(ON/OFF) button with the
remote controller headed toward the indoor unit,
and check if the beeping sound is heard ONCE.
1While pressing both OPERATION SELECT
button and TOO COOLbutton on the
remote controller at the same time,
press RESET button.
2First, release RESET button.
And release the other two buttons since all LCD
in operation display section of the remote controller
is displayed after 3 seconds.
Is the left lamp of OPERATION INDICATOR lamp on
the indoor unit blinking ? The indoor unit is abnormal .
Check the blinking pattern, and refer to confirm the
abnormal point(9-2.2.).
Press OPERATE/STOP(ON/OFF) button with the
remote controller headed toward the indoor unit,
and check if the beeping sound is heard TWICE.
The outdoor unit is abnormal
Check the blinking pattem, and refer to confirm the
abnormal point(Service manual OB391).
Did you press OPERATE/STOP(ON/OFF) button
for checking the abnormality of the indoor/outdoor unit
at least twice?
*Do not press any other buttons except for
OPERATE/STOP(ON/OFF) button while the unit is
operated in failure mode.
(Otherwise, failure mode may be released although it’s up
to the model.)
Is the left lamp of OPERATION INDICATOR lamp on
the indoor unit blinking ?
Blinking
No
Yes
Yes
Not Blinking
No
Not Blinking
No
Blinking
Yes
AMPM
CLOCK :
AMPM
•As for outdoor unit, refer to service manual OB391.
OB390--1qxp 05.2.9 11:27 Page 13

14
2. Indoor unit failure mode table
NOTE:Blinking patterns of this mode differs from the ones of Troubleshooting check table(9-4.).
5-time flash
2.5-second OFF
Replace the indoor electronic control
P.C. board.
Indoor control system When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
7-time flash
2.5-second OFF
Refer to the characteristic of sub
indoor coil thermistor(9-7.).
Sub indoor coil thermistor When the sub indoor coil thermistor shorts or
opens circuit is detected every 8 seconds
during operation.
3-time flash
2.5-second OFF
Refer to 9-6.A"Check of indoor fan
motor".
Indoor fan motor When the rotational frequency feedback
signal is not emited during 12-second the
indoor fan operation.
2-time flash
2.5-second OFF
Refer to the characteristic of the main
indoor coil thermistor (9-7.).
Main indoor coil thermistor When the main indoor coil thermistor shorts
or opens circuit is detected every 8 seconds
during operation.
1-time flash
2.5-second OFF
Refer to 9-6.D"How to check miswiring
and serial signal error".
Serial signal error When the serial signal from the outdoor
unit is not received for 4 to 5 seconds.
Not lighted –Normal –
Left lamp of
OPERAITON
INDICTOR Check point
Abnormal point
(Failure mode) Detection method
4-time flash
every 0.5-second
Refer to the characteristics of room
temperature thermistor (9-7.).
Room temperature
thermistor
When the room temperature thermistor shorts
or opens circuit is detected every 8
seconds during operation.
OB390--1qxp 05.2.9 11:27 Page 14

15
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Outdoor unit
operates in
only Test Run
operation.
Outdoor unit
doesn't
operate
even in
Test Run
operation.
Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.
Indoor unit
doesn't operate,
when
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage".
Refer to
"How to check
inverter/
compressor".
Refer to 9-6.B
"Check of
remote controller
and receiver
P.C. board".
1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to 9-6.C
"Check of indoor
electronic control
P.C. board".
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
Refer to
"Check of
R.V. coil".
Left lamp Flash
on and off at
0.5-second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
or trouble
of serial signal
Left lamp
2-time flash
Cause:
Indoor unit
• Trouble of
room temp-
erature/
indoor coil
thermistor
Left lamp
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Left lamp
5-time flash
Cause:
Outdoor unit
• Outdoor
power
system
abnormality
Left lamp
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
Left lamp
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to 9-6.D
"How to
check
mis-wiring
and serial
signal error
(when
outdoor unit
doesn't work)".
Both lamps
(Left and right)
Flash on and off
at 0.5-second
intervals
Cause:
Indoor unit
• The horizontal
vanes are not
installed
correctly.
Refer to 9-6.E
"Check of
installation of
the horizontal
vanes".
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to
"Test point
diagram and
voltage".
Refer to 9-6.A
"Check of
indoor fan
motor".
Refer to
"How to check
inverter/
compressor".
Refer to
"Check of
outdoor
thermistors".
Replace the
inverter P.C.
board or the
outdoor
electronic
control P.C.
board.
Left lamp
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
As for outdoor unit MUZ type,
refer to service manual OB391.
As for outdoor unit MXZ type,
refer to service manual OB319.
Indoor unit operates.
Outdoor unit doesn't
operate normally.
9-7.
9-3. Instruction of troubleshooting
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16
No.
1
2
4
5
6
SymptomOperation indicator lamp Detection method
Check point
Left lamp flashes.
0.5-second ON
0.5-second OFF
Mis-Wiring
or serial
signal
Outdoor
power
system
Outdoor
thermistors
Outdoor
control
system
Indoor coil
thermistor
3 minutes after power supply turns ON, when
the serial signal is not received.
When it consecutively occurs 3 times that
compressor stops for overcurrent protection
within 1 minute after start-up.
<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.
However, discharge temperature thermistor is
abnormal when open circuit is detected more
than 10 minutes after compressor start-up.
When it cannot properly read data in the
nonvolatile memory of the inverter P.C. board
or the outdoor electronic control P.C. board.
• Shortage of refrigerant
• Refer to "Check of outdoor
thermistor".
Refer to service manual
OB391 or OB319.
• Refer to "Check of inverter/
compressor".
Refer to service manual
OB391 or OB319.
• Replace the inverter P.C.
board or the outdoor
electronic control P.C. board.
Refer to service manual
OB391 or OB319.
• Refer to 9-6.D"How to check
mis-wiring and serial signal
error".
3Indoor fan
motor
7
Abnormal
point
Outdoor unit
does not
operate.
Room
tempera-
ture
thermistor
Left lamp flashes.
2-time flash
2.5-second OFF
When the indoor coil themistor or the room
temperature thermistor is short or open circuit
every 8 seconds during operation.
• Refer to the characteristics of
the indoor coil thermistor, and
the room temperature
thermistor
(9-7.).
Left lamp flashes.
3-time flash
2.5-second OFF
Indoor fan
repeats 12
seconds ON
and 3
minutes
OFF.
When the
indoor fan
breaks, the
fan keeps
stopping.
When the rotational frequency feedback
signal is not emit during 12-second indoor fan
operation. • Refer to 9-6.A"Check of
indoor fan motor".
Left lamp flashes.
4-time flash
2.5-second OFF
Indoor
control
system
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate. • Replace the indoor electronic
control P.C. board.
Left lamp flashes.
5-time flash
2.5-second OFF
Left lamp flashes.
6-time flash
2.5-second OFF
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
0.5-second ON
0.5-second OFF
When the electricity is not conducted to the
safety device (FAN) of the horizontal vane. • Refer to 9-6.E"Check of
installation of the horizontal
vanes".
Indoor unit
and outdoor
unit do not
operate.
Attachment
of the
horizontal
vane
Both lamps flash at the same time.
8
Operation Indicator
MXZ type
Operation
mode
setting
Lighted
Blinking
Outdoor unit
operates but
indoor unit
does not
operate.
When the operation mode of each indoor unit
is differently set to COOL(includes DRY) and
HEAT at the same time, the operation mode of
indoor unit that has operated at first has the
priority.
• Unify the operation mode.
Refer to service manual
OB319.
2.5-second OFF
Right lamp flashes
Left lamp flashes.
7-time flash
2.5-second OFF
9-4. Troubleshooting check table
NOTE : Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
Self check table
Operation Indicator · Flashing of the OPERATION INDICATOR lamp (left-hand side or both lamp)
indicates possible abnormalities.
· The OPERATION INDICATOR lamp (left-hand side lamp) is
lighting during normal operation.
Lighted
Not lighted
• The following indication applies regardless of shape of the indicator.
Blinking
OB390--1qxp 05.2.9 11:27 Page 16

17
9-5. Trouble criterion of main parts
MSZ-CA25VB - MSZ-CA35VB - E1E1
Part name FigureCheck method and criterion
Indoor fan motor(MF)
INNER FUSE
136i3:CUT OFF
WHT – BLK
BLK – RED
Abnormal
Open or
short-circuit
Normal
MSZ-CA25VB
303 "~ 329 "
287 "~ 311 "
MSZ-CA35VB
396 "~ 430 "
320 "~ 348 "
Measure the resistance with a tester. (Part temperature 10˚C ~ 30˚C)
Normal
8 k"~ 20 k"Abnormal
Open or short-circuit
Room temperature
thermistor(RT11)
Indoor coil thermistor
(RT12(MAIN), RT13(SUB))
Vane
motor(MV)
Motor part
Sensor part
Measure the resistance between the terminals with a tester.
(Part temperature 10˚C ~ 30˚C)
BRN – YLW
YLW – GRY
Abnormal
Remain 0V or 5V
Normal
4.5 ~ 5.5V
Measure the voltage power ON.
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
Normal
BRN-other one Abnormal
Open or short-circuit
Measure the resistance between the terminals with a tester.
(Part temperature 10°C ~ 30°C)
Color of lead wire
Color of lead wire
BLK
RED
WHT
GRY
YLW BRN
240 "~ 260 "
Color of lead wire
MAIN
AUX.
FUSE
RED
YLW
BRN
ORN GRN
ROTOR
Check of indoor fan motor
A
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan does not operate.
Turn OFF the power supply.
Check the connector (Fan motor) visually.
Replace the indoor fan motor.
Disconnect the lead wires from the connector (Indoor fan motor).
Measure the resistance between lead wires No.1 and No.5 and then No.3 and No.5 of the indoor fan
motor on CN211.
Are lead wires connected?
Reconnect the lead wires.
Is soldered point of the connector
correctly soldered?
Replace the indoor electronic control
P.C. board.
Resolder it.
Is the resistance 0 (short circuit) or ∞(open circuit)?
Yes ( 0 or ∞)No
(others)
Yes
No
Yes
No
9-6. Troubleshooting flow
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18
Check of indoor electronic control P.C. board
C
The unit doesn’t operate with the remote controller.
Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.
Indoor electronic
control P.C. board
Varistor (NR11)
Indoor electronic
control P.C. board
Fuse (F11) 1
3
CN201 F12 N
2
3
Thermal fuse connector
Terminal
block
Check both “parts side” and “pattern side” of the
indoor electronic control P.C. board visually.
Replace the fuse.
Is fuse (F11) blown?
Replace the fan motor.
Is winding resistance
of fan motor 0 "?
Is winding resistance
of vane motor 0 "?
No
Yes
No
Replace the vane motor.
Yes
No
Yes
Is varistor (NR11) burnt?
Replace the varistor.
Yes
Turn OFF the power supply.
Disconnect indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
No
Does the unit operate with the remote controller or
does OPERATION INDICATOR lamp light up
by pressing EMERGENCY OPERATION switch?
Yes
No
Turn OFF the
power supply. Turn OFF the
power supply.
Replace the indoor
electronic control
P.C. board.
Measure the
resistance
between
CN201 1on
the indoor
electronic control
P.C. board and N
on the terminal
block with the
tester.
Is resistance approx. 0"?
Replace the fuse (F12).
No
Yes
(∞)
Check of remote controller and receiver P.C. board
B
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but does not operate with the remote controller.
wCheck if the remote controller is exclusive for this air conditioner.
CN302
CN125 CN109
1 2
1 2
3 1
543
Remote
controller
Indoor electronic control
P.C. board
Power monitor
receiver P.C.
board
Yes
Yes
Replace the batteries.(Refer to 9-1.4.)
Turn on a radio to AM and press switch on
the remote controller.
Is noise heard from the radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Measure the voltage between receiver P.C. board connector CN302 No.3(-) and No.5(+) when the remote
controller button is pressed.
Is the voltage approx. 4V DC? Replace the indoor electronic control P.C.
board.
Replace the receiver P.C. board.
Replace the remote controller.
● Reinstall the unit away from lights.
● Attach a filter on receiving part.
Switch on the remote controller.
Is LCD display on the the remote
controller visible?
Remove the batteries, then set them back
and press RESET button. (Refer to 9-1.4.)
Check if the unit operates with the remote
controller.
Yes
Does the unit operate with the
remote controller?
Yes
OK
No
(not clear)
Yes
No
No
No(5V or 0V DC)
No
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19
How to check mis-wiring and serial signal error (when outdoor unit does not work)
D
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
No Replace the
indoor/ outdoor
connecting wire.
Is there voltage approximate 280V DC between
LD61A (+) and LD66A (–) on the inverter P.C.
board arter 3 minutes?
Turn OFF the power supply and then turn ON
again.
Press EMERGENCY OPERATION switch.
After 3 minutes, is there approximate 230V AC
between outdoor terminal block 2and N?
w4 Replace the inverter P.C.
board.
Does the right side of OPERATION INDICATOR
lamp blink quickly?
w2 Mis-wiring may damage indoor electronic
control P.C. board during the operation.
Be sure to confirm the wiring is correct
before the operation starts.
Replace the indoor
electronic control
P.C. board.
No
Replace the indoor/ outdoor connecting wire.
Release the failure mode. w3
Yes
Yes
A
B
Turn OFF the power supply.
Disconnect the indoor/ outdoor connecting wire.
Short-circuit indoor terminal block Nand 3.
Turn ON the power supply.
While pressing both OPERATION SELECT button and
TOO COOL button on the remote controller at the same
time, press RESET button.
At first, release RESET button.
And release the other two buttons since all LCD in
operation display section of the remote controller is
displayed after 3 seconds.
Transmit the signal of remote controller, pressing
OPERATE/STOP (ON/OFF) button on the remote
controller.
(The above procedure allows OPERATION INDICATOR
lamp to indicate the failure-mode.)
Remove the short-circuit between indoor terminal block N
and 3.
Reconnect the indoor/ outdoor connecting wire.
Turn ON the power supply.
Press EMERGENCY OPERATION switch.
Is there amplitude of 5 to 10V DC between outdoor
terminal block Nand 3after 3 minutes (for confirmation of
serial signal)?
1. Turn OFF the power supply.
2. Disconnect the connector (CN61) between the
compressor and the power transistor module.
3. Turn ON the power supply.
4. Press EMERGENCY OPERATION switch.
No
Yes
No
Yes
(light up or OFF)
Is mis-wiring
indicated when
the contactor
(52C) on the
indoor electronic
control P.C.
board turns ON
3 minutes later?
Yes
No
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON again.
· Press EMERGENCY OPERATION
switch.
B
· Reinstall
either the
unit or the
light each
other away.
· Attach a filter
on receiving
section of
the indoor
unit.
w3 Be sure to release the failure-mode
recall function after checking.
w4 Be careful to the residual voltage of smoothing capacitor.
Procedure of release of failure-mode.
1Press EMERGENCY OPERATION
switch.
2Turn OFF the power supply.
3Press RESET button on the
remote controller.
Start
No
• Turn ON the power supply.
•
Press once EMERGENCY OPERATION switch.
Is there any mis-wiring, poor contact,
or wire disconnection? w2
Make them sure. Yes
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on indoor unit.w
wShort circuit of JPG and JPS on the indoor
electronic control P.C. board enables
self-check to be displayed in 3 seconds.
Yes
Is there 230V AC between outdoor terminal
block 2and N?
No Replace the
indoor/ outdoor
connecting wire.
A
•The following indication
applies regardless of shape
of the indicator.
Blinking
Operation Indicator
As for outdoor unit MUZ type, refer to service manual OB391.
As for outdoor unit MXZ type, refer to service manual OB319.
AMPM
CLOCK
:
AMPM
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20
Check of installation of the horizontal vanes
E
Turn OFF the
power supply. Replace the
thermal fuse (F12).
Is resistance ∞between the connector CN 201 1 on indoor
electronic control P.C. board and the terminal block N?Yes
No
CN201
Indoor electronic
control P.C. board
Ok
Start
Replace the
indoor electronic
control P.C. board.
Replace the
safety device.
Is the stopper of the horizontal vane
locked to the indoor unit correctly?
Yes
No
Is there resistance 0 "?
Relock the stopper of the
horizontal vane to the indoor unit.
Refer to 9-1.5.
Yes
Is OPERATION
INDICATOR lamp flashing?
Yes
No(∞)
No OK
Turn ON the
power supply.
To check the continuity of safety device,
measure the resistance of connector 1- 3
connected to CN1R1 on the indoor
electronic control P.C. board.
Turn OFF the
power supply.
Turn OFF the
power supply.
When both OPERATION INDICATOR lamps flash 1-time.
Indoor unit and outdoor unit don’t operate.
Check of thermal fuse
F
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