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Page 1
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
No. OB345
SERVICE MANUAL
Wireless type
Models
MSZ-A18YV MSZ-A24YV MSZ-A26YV -
E1
E1
E1
CONTENTS
Indication of model name
MSZ-A18YV MSZ-A24YV MSZ-A26YV -
E1
E1
1. PART NAMES AND FUNCTIONS······················2
2. SPECIFICATION·················································4
3. NOISE CRITERIA CURVES ·······························5
4. OUTLINES AND DIMENSIONS ·························6
5. WIRING DIAGRAM ············································7
6. REFRIGERANT SYSTEM DIAGRAM ················8
7. SERVICE FUNCTIONS ······································9
8. TROUBLESHOOTING······································11
9. DISASSEMBLY INSTRUCTIONS ····················19
10. PARTS LIST······················································21
11. OPTIONAL PARTS ···········································23
E1
NOTE:
This service manual describes technical data of the indoor unit.
•Refer to the service manual OB346 when MSZ-A18YV - E1 , MSZ-A24YV - E1 or MSZ-A26YV is connected with MUZ-A18YV - E1 , MUZ-A24YV - E1 or MUZ-A26YV - E1 .
•Refer to the service manual OB319 when MSZ-A18YV - E1 , MSZ-A24YV - E1 or MSZ-A26YV is connected with MXZ-A26WV - E1 or MXZ-A32WV - E1 as multi system units.
E1
E1
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PART NAMES AND FUNCTIONS
INDOOR UNIT
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
Air cleaning filter (option)
(White bellows type)
Grille
Air inlet
To Breaker
Power supply cord
Catechin air filter
Remote control
receiving section
Vertical vanes
Horizontal vane
Remote controller
Operation section
Display section
(When the grille is opened)
Operation indicator lamp
Emergency operation switch
Remote control
receiving section
ACCESSORIES
Indoor unit
1
2
3
4
5
6
7
Installation plate
Installation plate fixing screw 4 o 25 mm
Remote controller holder
Fixing screw for 3 o 3.5 o 1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
2
MSZ-A18YV MSZ-A24YV MSZ-A26YV 1
7
1
2
2
1
1
E1
E1
E1
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REMOTE CONTROLLER
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
Signal transmitting section
Operation display section
PM
OPERATE /STOP
(ON /OFF)button
AM
TOO
ON/OFF WARM
TOO
COOL
TEMPERATURE buttons
Indication of remote controller
model is on back.
Open the front lid.
CLOCK
PM
AM
TOO
ON/OFF WARM
VANE button
(Horizontal vane button)
TOO
COOL
FAN
STOP
VANE
START
I FEEL COOL
FAN SPEED CONTROL button
OFF-TIMER button
HEAT DRY
ON-TIMER button
MODE WIDE VANE
HR.
OPERATION SELECT button
ECONO COOL
LONG
ECONO COOL button
MIN.
HR. button
MIN. button
(TIME SET button)
RESET CLOCK
CLOCK SET button
WIDE VANE button
(Vertical vane button)
LONG button
RESET button
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SPECIFICATION
•Refer to the service manual OB346 when MSZ-A18YV - E1 , MSZ-A24YV MUZ-A18YV - E1 , MUZ-A24YV - E1 or MUZ-A26YV - E1 .
•Refer to the service manual OB319 when MSZ-A18YV - E1 , MSZ-A24YV MXZ-A26WV - E1 or MXZ-A32WV - E1 as multi system units.
E1
or MSZ-A26YV -
E1
is connected with
E1
or MSZ-A26YV -
E1
is connected with
Capacity Air flow(High/Med.w/Low w ) K /h
Power outlet
A
Running current ✽1
A
Power input ✽1
W
Auxiliary heater
A(kW)
Power factor ✽1
%
Fan motor current ✽1
A
Model
Winding
"
resistance(at 20:)
Dimensions WOHOD
mm
Weight
kg
Air direction
Sound level(High/Med.w /Low w)
dB
Fan speed(High/Med.w /Loww ) rpm
Fan speed regulator
Thermistor RT11(at 25:)
k"
Thermistor RT12(at 25:)
k"
Thermistor RT13(at 25:)
k"
Remote controller model
MSZ-A18YV - E1
Cooling
Heating
Single phase
230V, 50Hz
852/690 w/498 w
10
0.30
60
—
87
0.30
RC4V32-AA
WHT-BLK 293
BLK-RED 146
1,100O325O258
16
5
43/38w /31 w
1,120/940w /720w
3
10
10
10
KP0A
Indoor model
Function
Cooling
Indoor model
Function
Special
remarks
Fan
motor
Electrical
data
Power supply
MSZ-A24YV - E1
Heating
Cooling
Single phase
230V, 50Hz
1,032/768 w/522 w
1,032/786 w/522 w
10
0.34
69
—
87
0.34
RC4V40-AA
WHT-BLK 138.2
BLK-RED 159.0
1,100O325O258
16
5
48/40w /32 w
1,310/1030 w/750 w
1,310/1050 w /750 w
3
10
10
10
KP0A
MSZ-A26YV -
E1
Heating
Single phase
230V, 50Hz
Power supply
1,032/816 w/564w
Special
remarks
Fan
motor
Electrical
data
Capacity Air flow(High/Med.w/Low w ) K /h
1,032/798 w/564 w
A
10
Power outlet
A
0.34
Running current ✽1
W
69
Power input ✽1
A(kW)
—
Auxiliary heater
%
88
Power factor ✽1
A
0.34
Fan motor current ✽1
RC4V40-AA
Model
WHT-BLK 138.2
Winding
"
BLK-RED 159.0
resistance(at 20:)
mm
1,100O325O258
Dimensions WOHOD
kg
16
Weight
5
Air direction
dB
48/40 w/33 w
Sound level(High/Med.w/Low w )
Fan speed(High/Med.w /Low w ) rpm
1,310/1,060 w/800 w
3
Fan speed regulator
k"
10
Thermistor RT11(at 25:)
10
Thermistor RT12(at 25:) k"
10
Thermistor RT13(at 25:) k"
Remote controller model
KP0A
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C
Outdoor Dry-bulb temperature 35°C Wet-bulb temperature(24°C)
Heating : Indoor Dry-bulb temperature 20°C Wet-bulb temperature 15.5°C
Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C
Indoor-Outdoor piping length 5m
w Reference value
✽1 Measured under rated operating frequency.
4
1,310/1,080 w/800 w
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Specifications and rating conditions of main electric parts
INDOOR UNIT
Model
Item
MSZ-A18YV -
MSZ-A24YV -
E1
Indoor fan capacitor
(C11)
2.5+ 440V
Fuse
(F11)
250V 3.15A
(MV1/ MV2)
Vane motor
Varistor
Solid state relay
TNR10V511K410
(SR141)
S201DH1N
(TB)
3P
145:
Indoor fan motor thermal fuse
3
NOISE CRITERIA CURVES
MSZ-A18YV - E1
FAN SPEED SPL(dB(A))
High
LINE
MSZ-A24YV - E1
MSZ-A26YV - E1
High
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
70
NC-70
60
NC-60
50
NC-50
40
NC-40
30
NC-30
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
63
125
NC-20
500
1000
2000
4000
48
80
70
NC-70
60
NC-60
50
NC-50
40
NC-40
30
NC-30
20
10
250
LINE
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
Heating : Dry-bulb temperature 20: Wet-bulb temperature 15.5:
90
80
10
FAN SPEED SPL(dB(A))
43
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
Heating : Dry-bulb temperature 20: Wet-bulb temperature 15.5:
90
20
E1
MP20/MP20
(NR11)
Terminal block
MSZ-A26YV -
E1
8000
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
63
125
NC-20
250
500
1000
2000
4000
8000
BAND CENTER FREQUENCIES, Hz
BAND CENTER FREQUENCIES, Hz
INDOORUNIT
WALL
1m
0.8m
MICROPHONE
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OUTLINES AND DIMENSIONS
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
INDOOR UNIT
Unit: mm
Installation plate
Indoor unit
7.5
173
98
414.5
414.5
173
47
2.5
47
255.5
1068
315
98
Wall hole [75
258
1100
Air in
5
Installation plate
{
Liquid line [ 6.35- 0.5m
Gas line [ 12-0.43m
Insulation [ 50 O.D
[ 32 I.D
for MSZ-A18/A24YV
Liquid line [ 9.52- 0.5m
Gas line [ 12-0.43m
Insulation [ 50 O.D
[ 32 I.D
for MSZ-A26YV
325
{
791
56
253
Air out
19
162
58
Drain hose [16
(Connected part O.D)
Insulation [28
Power supply cord
Lead to right 2.0m
Lead to left 1.0m
Wireless remote controller
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WIRING DIAGRAM
MSZ-A18YV - E1
MODEL WIRING DIAGRAM
INDOOR UNIT
TO OUTDOOR
UNIT
CONNECTING TB
3
12V
CN201
RED
N
BLU
L
POWER
SUPPLY
CORD
~/N 230V
50Hz
BRN
CN
151
BRN
BLU
CIRCUIT
BREAKER
SYMBOL
NR11
3
2
1
TRANS
TAB12
F11
NAME
3
1
3
4
C11
SR141
CN
111
ELECTRONIC CONTROL P.C. BOARD
MF
RT11
3
RECEIVER
P.C. BOARD
DISPLAY
P.C. BOARD
REMOTE
CONTROLLER
SYMBOL
NAME
SYMBOL
NAME
MV1
VANE MOTOR (HORIZONTAL)
RT12
INDOOR COIL THERMISTOR (MAIN)
RT13
INDOOR COIL THERMISTOR (SUB)
C11
INDOOR FAN CAPACITOR
F11
FUSE (3.15A)
MV2
VANE MOTOR (VERTICAL)
HIC1
DC/DC CONVERTER
NR11
VARISTOR
INDOOR FAN MOTOR (INNER FUSE)
RT11
ROOM TEMPERATURE THERMISTOR
MF
CN
121
RT12
BLK 1
GRY 2
YLW 3
BRN 4
WHT 5
RED 6
CN211
CN
101
3
MV2 MV2 MV1
RT13
CN112
CN
102
15
GRN/YLW
PE
4
3
2
1
HIC1
SOLID STATE RELAY
SR141
TERMINAL BLOCK
TB
NOTES: 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.
: Connector
: Terminal block
MSZ-A24YV - E1
MSZ-A26YV - E1
INDOOR UNIT
MODELS WIRING DIAGRAM
TO OUTDOOR
UNIT
CONNECTING TB
3
12V
PE
CIRCUIT
BREAKER
SYMBOL
CN201
RED
N
POWER
SUPPLY
CORD
~/N 230V
50Hz
BLU
L
CN112
3
2
1
NR11
TRANS
BRN
BRN
BLU
15
NAME
CN
101
3
MV2 MV2 MV1
ELECTRONIC CONTROL P.C. BOARD
1
3
4
3
RT12
BLK
GRY
YLW
BRN MF
WHT
RED
CN
111
RT11
3
RECEIVER
P.C. BOARD
DISPLAY
P.C. BOARD
SYMBOL
REMOTE
CONTROLLER
NAME
INDOOR FAN CAPACITOR
MV2
VANE MOTOR(VERTICAL)
F11
FUSE (3.15A)
NR11
VARISTOR
DC/DC CONVERTER
RT11
ROOM TEMPERATURE THERMISTOR
MF
INDOOR FAN MOTOR (INNER PROTECTOR)
RT12
INDOOR COIL THERMISTOR (MAIN)
MV1
VANE MOTOR (HORIZONTAL)
RT13
INDOOR COIL THERMISTOR (SUB)
NOTES: 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
C11
RT13
CN211
CN
102
CN
151
CN
121
SR141
F11
TAB12
C11
HIC1
4
3
2
1
HIC1
GRN/YLW
OB345-1.qxp
: Connector
7
SYMBOL
SR141
TB
NAME
SOLID STATE RELAY
TERMINAL BLOCK
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REFRIGERANT SYSTEM DIAGRAM
MSZ-A18YV - E1
MSZ-A24YV - E1
INDOOR UNIT
INDOOR UNIT
Refrigerant pipe [15.88
(with heat insulator)
Refrigerant pipe [12.7
(with heat insulator)
Indoor
heat
exchanger
Indoor coil
thermistor
RT12(main)
Distributor
Indoor
heat
exchanger
Indoor coil
thermistor
RT12(main)
Distributor
Flared connection
Indoor coil
thermistor
RT13(sub)
Room temperature
thermistor
RT11
Flared connection
Flared connection
Refrigerant pipe[6.35
(with heat insulator)
Refrigerant pipe [6.35
(with heat insulator)
MSZ-A26YV - E1
INDOOR UNIT
Refrigerant pipe [15.88
(with heat insulator)
Indoor coil
thermistor
RT12(main)
Flared connection
Indoor coil
thermistor
RT13(sub)
Room temperature
thermistor
RT11
Indoor
heat
exchanger
Unit:mm
Flared connection
Indoor coil
thermistor
RT13(sub)
Room temperature
thermistor
RT11
Strainer
#50
Flared connection
Refrigerant pipe [9.52
(with heat insulator)
Refrigerant flow in cooling
Refrigerant flow in heating
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SERVICE FUNCTIONS
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
7-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board.
The time will be shortened as follows.
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.)
7-2. 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.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below :
Remote controller model : KP0A
J2
NOTE : For remodelling, take out the batteries and press the
OPERATE/STOP(ON/OFF)button
twice or 3 times at first.
After finish remodelling, put back
the batteries then press the
RESET button.
J1
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 the RESET button.
Table 1
1 unit operation
2 units operation
3 units operation
4 units operation
No. 1 unit
No modification
Same as at left
Same as at left
Same as at left
No. 2 unit
–
Solder J1
Same as at left
Same as at left
No. 3 unit
–
–
Solder J2
Same as at left
No. 4 unit
–
–
–
Solder both J1 and J2
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.
7-3. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, 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.
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How to release “AUTO RESTART FUNCTION”
1Turn off the main power for the unit.
2Pull out the electronic control P.C. board, the receiver P.C.
board and the display P.C.board. (Refer to page 19.)
3Solder jumper wire to the RESISTOR JR07 on the indoor
electronic control P.C. board. (Refer to page 18.)
C11
CN
21
1
CN201
SW1
RA102
CN151 CN121
CN111
CN112
TAB12
IC101
IC152
JR07
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.)
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
cancelled.
•If the unit has been off with the remote controller before power failure, the auto restart function does not work as the
power button of the remote controller is off.
•To prevent breaker off due to the rush of starting current, systematize other home appliances 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.
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TROUBLESHOOTING
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
8-1. 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
3. Troubleshooting procedure
(1) First, check if the 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 discolouration.
(4) When troubleshooting, refer to the flow chart on page 12 and the check table on page 13.
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.
1 Remove the front lid and insert batteries.
2 Press the RESET button with tip end of ball point
Then reattach the front lid.
pen or the like, and then use the remote controller.
Insert the negative pole
of the batteries first.
Check if the polarity of
the battereis is correct.
RESET button
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
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.
Operation Indicator
Lighted
Blinking
•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.
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8-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit
operates in
only Test Run
operation.
Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage".
Outdoor unit
doesn't
operate
even in
Test Run
operation.
Refer to
"Check of
inverter/
compressor".
Indoor unit operates.
Outdoor unit doesn't
operate normally.
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
Refer to
"Check of
R.V. coil".
Flash on and
off at 0.5second
interval
Cause:
Indoor/
Outdoor unit
• Mis-wiring
or trouble of
serial signal
2-time flash
Cause:
Indoor unit
• Trouble of
room temperature/
indoor coil
thermistor
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Refer to D
"How to
check miswiring and
serial signal
error (When
outdoor unit
doesn't
work)" on
page 17.
Check room
temperature
thermistor
and indoor
coil thermistor.
Refer to
"Test point
diagram and
voltage".
Refer to A
"Check of
indoor fan
motor" on
page 15.
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
operates, when
the EMERGENCY
OPERATION
switch is pressed.
Refer to
"Check of
remote controller
and receiver
P.C. board".
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is pressed.
1. Check indoor/ outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to
"Check of indoor
electronic control
P.C. board".
7-time flash
5-time flash
6-time flash
Cause:
Cause:
Cause:
Outdoor unit
Outdoor unit
Outdoor unit
• Trouble of
• Outdoor
• Trouble of
outdoor
power
thermistor
control
system
in outdoor
system
abnormality
unit
Refer to
"Check of
inverter/
compressor".
As for outdoor unit MUZ type, refer to service manual OB346.
As for outdoor unit MXZ type, refer to service manual OB319.
12
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Refer to
"Check of
outdoor
thermistors".
Replace the
outdoor
electronic
control P.C.
board.
OB345-1.qxp
04.4.22 11:44 AM
Page 13
1. Troubleshooting check table
• The following indication applies regardless of shape of the indicator.
· Flashing of the OPERATION INDICATOR lamp (the left-hand side lamp) indicates
possible abnormalities.
· The OPERATION INDICATOR lamp (the left-hand side lamp) is lighting during
Not lighted
normal operation.
Operation Indicator
Lighted
Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
No.
Abnormal
point
Mis-Wiring
1 or Serial
signal
Indoor coil
thermistor
2
Room
temperature
thermistor
Operation indicator lamp
0.5-second ON
0.5-second OFF
2-time flash
3
Detection method
Outdoor unit
does not
operate.
3 minutes after power supply turns ON, when
serial signal is not received.
• Refer to D "How to check
mis-wiring and serial signal
error" on page 17.
Outdoor unit
does not
operate.
Detect Indoor coil/room temperature
thermistor short or open circuit every 8
seconds during operation.
• Refer to the characteristics of
main indoor coil thermistor,
sub indoor coil thermistor,
and room temperature
thermistor on page 18.
2.5-second OFF
3-time flash
Indoor fan
motor
2.5-second OFF
4-time flash
Indoor
4 control
system
Checkpoint
Symptom
Indoor fan repeats
12 seconds ON
When rotational frequency feedback signal is
and 3minutes OFF. not emit during 12-second indoor fan
When the indoor
operation.
fan breaks, the fan
keeps stopping.
• Refer to A "Check of
indoor fan motor" on page 15.
Outdoor unit
does not
operate.
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
• Check the indoor electronic
control P.C. board.
Outdoor unit
does not
operate.
When compressor has stopped due to over
current protection or start-up failure protection
3 times in a row within 5 seconds after startup.
• Refer to "Check of inverter/
compressor".
Refer to service manual
OB346 or OB319.
Outdoor unit
does not
operate.
<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.
• Shortage of refrigerant
• Replace the outdoor control
P.C. board.
Refer to "Check of outdoor
thermistor".
Refer to service manual
OB346 or OB319.
2.5-second OFF
5
Outdoor
power
system
5-time flash
2.5-second OFF
6-time flash
6
Outdoor
thermistors
2.5-second OFF
7
Outdoor
control
system
7-time flash
2.5-second OFF
Right lamp flashes.
8
MXZ type
Operation
mode
setting
Operation Indicator
Lighted
2.5-second OFF
Blinking
Outdoor unit
does not
operate.
When it cannot properly read data in the
nonvolatile memory of outdoor electronic
control P.C. board.
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 same time, the operation mode of
indoor unit that has operated at first has the
priority.
• Replace the outdoor
electronic control P.C. board.
Refer to service manual
OB346 or OB319.
• Unify the operation mode.
Refer to service manual
OB319.
NOTE : When the indoor unit has started operation and the above detection method has detected an abnormality (the first
detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with the
OPERATION INDICATOR lamp flashing.
13
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Page 14
2. Trouble criterion of main parts
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
Part name
Figure
Check method and criterion
Measure the resistance with a tester.
Room temperature
(Part temperature 10˚C ~ 30˚C)
thermistor(RT11)
Normal
Abnormal
Indoor coil thermistor
Open
or short-circuit
8
k"
~
20
k"
(RT12(main), RT13(sub))
MSZ-A18YV
Horizontal vane
motor(MV1)
Vertical vane
motor(MV2)
Abnormal
Open or
short-circuit
FUSE
BLK
BRN
YLW
GRY
RED
WHT
Normal
MSZ-A24/A26YV
MSZ-A18YV
132 " ~ 144 "
282 " ~ 305 "
152 " ~ 166 "
141 " ~ 152 "
MSZ-A24/A26YV
Measure the voltage power ON.
Color of lead wire
BRN – YLW
YLW – GRY
Normal
4.5 ~ 5.5V
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
MAIN
AUX.
Abnormal
P
Remain 0V or 5V
Measure the resistance between the terminal with a tester.
(Part temperature 10°C ~ 30°C)
Normal
Abnormal
Open or short-circuit
282 " ~ 306 "
RED
WHT
MSZ-A24/A26YV
INNER
PROTECTOR
135i 5: OPEN
86i 15: CLOSE
Color of
lead wire
WHT – BLK
BLK – RED
MAIN
AUX
BLK
BRN
YLW
GRY
RED
MSZ-A18YV
INNER FUSE
145: CUT OFF
Sensor part
Indoor fan motor(MF)
Motor part
Measure the resistance between the terminals with a tester.
(Part temperature 10˚C ~ 30˚C)
ROTOR
YLW
BRN
ORN
GRN
P :INNER PROTECTOR
14
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Page 15
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
A Check of indoor fan motor
Turn OFF the power supply.
Check connector CN211 visually.
No
Are lead wires connected?
Yes
Is soldered point of the connector
correctly soldered?
No
Resolder it.
Yes
Reconnect the lead wires.
Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board.
Measure resistance between lead wires No.3 and No.4 and then No.1 and No.4.
Is resistance 0 (short circuit) or ∞ (open circuit)?
Yes ( 0 or ∞ )
No
(others)
Turn ON the power supply. Stop it if the unit operate.
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure
voltage between No.2(+) and No.3(-) on CN121.
No
Repair or replace the indoor fan motor.
Does voltage repeat 0V DC and 5V DC?
Yes
Replace the indoor electronic control P.C. board.
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.
B Check of remote controller and receiver P.C. board
w Check if the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is LCD display on the the remote
controller visible?
No
Replace the batteries.(Refer to page 11.)
(not clear)
Yes
Remove the batteries, then set them back
and press the RESET button. Check if the
unit operates with the remote controller.
Does the unit operate with the
remote controller?
No
Turn on a radio to AM and press switch on
the remote controller.
Yes
No
OK
Is noise heard from radio?
Replace the remote controller.
Yes
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Yes
● Reinstall the unit away from lights.
● Attach a filter on receiving part.
No
Measure the voltage between receiver P.C. board connector CN301 No.1(+) and No.3(-) when the remote
controller button is pressed.
Yes
Is the voltage approx. 4V DC?
No(5V or 0V DC)
Replace the receiver P.C. board.
15
Replace the indoor electronic control P.C.
board.
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04.4.22 11:44 AM
Page 16
The unit doesn’t operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.
C Check of indoor electronic control P.C. board
Check the both “parts side” and “pattern
side” of indoor electronic control P.C.
board visually.
Varistor (NR11)
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
Fuse (F11)
Indoor electronic
control P.C. board
No
Yes
Turn OFF the
power supply.
Replace the vane
motor.
Turn OFF the
power supply.
Yes
Is winding
resistance of
vane motor 0 "?
Replace the fuse.
No
Is winding
resistance of
fan motor 0 "?
Yes
No
Is fuse(F11) blown?
No
Yes
Replace the fan
motor.
Is varistor(NR11) burnt?
Yes
Replace the varistor.
16
No
Replace the indoor
electronic control
P.C. board.
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04.4.22 11:44 AM
Page 17
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn’t operate.
D How to check mis-wiring and serial signal error (when outdoor unit does not work)
Start
• Turn ON the power supply (Indoor/ outdoor unit).
• Press once EMERGENCY OPERATION switch.
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on the indoor unit.w
Yes
Make them sure.
w Short circuit of JPG and JPS on the indoor
electronic control P.C. board enables
self-check to be displayed in 3 seconds.
Is there any mis-wiring, poor contact,
or wire disconnection? w2
No
A
B
˚C
CLOCK
AMPM
AMPM
•The following indication
applies regardless of shape
of the indicator.
Turn OFF the power supply (Indoor/ outdoor unit).
Disconnect the indoor/ outdoor connecting wire.
Short-circuit indoor terminal block N and 3.
Turn ON the power supply (Indoor/ outdoor unit).
During pressing the OPERATION SELECT button on
the remote controller, press the RESET button.
At first, release the RESET button.
And release the OPERATION SELECT button 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.)
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.
Blinking
Does the right side of OPERATION INDICATOR
lamp blink quickly?
Operation Indicator
No
(light up or OFF)
Replace the indoor
electronic control
P.C. board.
Yes
Release the failure mode. w3
Remove the short-circuit between indoor terminal block N
and 3.
Reconnect the indoor/ outdoor connecting wire.
Turn ON the power supply (Indoor/ outdoor unit).
Press the EMERGENCY OPERATION switch.
Is there amplitude of 5 to 10V DC between outdoor
terminal block N and 3 after 3 minutes (for confirmation of
serial signal)?
Yes
Reconnect the
power supply
cable.
No
Is there 230V AC between outdoor terminal
block L and N?
Yes
Check of power
supply.
No
Is there 325V DC between CN801 1 and 3 on the
outdoor electronic control P.C. board?
Yes
Replace the outdoor
electronic control P.C.
board.
As for outdoor unit MUZ type, refer to service manual OB346.
As for outdoor unit MXZ type, refer to service manual OB319.
No
Replace the
indoor/ outdoor
connecting wire.
w3 Be sure to release the failure-mode
recall function after checking.
Procedure of release of failure-mode.
1 Press the EMERGENCY
OPERATION switch.
2 Turn OFF the power supply
(Indoor/ outdoor unit).
3 Press the RESET button on the
remote controller.
A
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON again (Indoor/ outdoor unit).
· Press the EMERGENCY
OPERATION switch.
After 3 minutes,
is mis-wiring
indicated on
OPERATION
INDICATOR
lamp on the
indoor unit?
Yes
B
17
· Reinstall
either the
unit or the
light each
No
other away.
· Attach a filter
on receiving
section of
the indoor
unit.
OB345-1.qxp
04.4.22 11:44 AM
Page 18
TEST POINT DIAGRAM AND VOLTAGE
MSZ-A18YV - E1 MSZ-A24YV - E1 MSZ-A26YV - E1
Indoor electronic control P.C. board
Fan motor power supply
}
+
Fuse (F11)
250V AC 3.15A
Power supply input
230V AC
} 5V DC
Room temperature thermistor(RT11)
Indoor coil
thermistor(RT12(main))
R132
Indoor coil
thermistor(RT13(sub))
Emergency operation
switch
Timer short mode point
(JPS, JPG)
(Refer to page 9.)
+
}
Receiver P.C. board
12V DC
Release of “Auto restart function”
Solder jumper wire to JR07.
(Refer to page 10.)
18
Resistance(k")
Indoor coil thermistor(RT12(main), RT13(sub))
Room temperature thermistor (RT11)
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9
Page 19
DISASSEMBLY INSTRUCTIONS
<"Terminal with lock mechanism" Detaching points>
In case of terminal with lock mechanism, detach the terminal as shown below.
There are two types ( Refer to (1) and (2)) of the terminal with lock mechanism.
The terminal with no lock mechanism can be removed by pulling it out.
Check the shape of the terminal and work.
(1) Slide the sleeve and check if there is a locking lever or not.
(2) The terminal with this connector is a terminal
with lock mechanism
Sleeve
Locking lever
MSZ-A18YV - E1
INDOOR UNIT
1Slide the sleeve.
2Pull the terminal while
pushing the locking
lever.
MSZ-A24YV - E1
1Hold the sleeve, and
pull out the terminal
slowly.
Connector
MSZ-A26YV - E1
OPERATING PROCEDURE
PHOTOS
1. Removing the front panel
(1) Remove the screw caps of the front panel.
Remove the screws.
(2) Pull the panel down to your side slightly and unhook the
catches at the top.
Photo 1
Front panel
Screws
2. Removing the electronic control P.C. board, the receiver
P.C. board and the display P.C. board
(1) Remove the front panel. (Refer to 1.)
(2) Remove the screw of the electrical cover.
Remove the electrical cover.
(3) Remove the screws of the V.A. clamp.
Remove the V.A. clamp.
(4) Remove the screw of the terminal block.
(5) Remove the screws of the ground wire.
(6) Disconnect all the connectors and all the lead wires on the
electronic control P.C. board.
(7) Remove the R.L holder.
(8) Remove the electronic control P.C. board.
(9) Open the R.L holder, remove the receiver P.C. board and
the display P.C. board.
Photo 2
Screws of the ground wire
Fan motor
connectors
Vane motor
connector
Indoor
electronic
control
P.C. board
Screw of
the electrical
cover
Receiver Screw of the
Screw of
R.L
V.A. clamp
holder the terminal P.C.
board
block
19
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04.4.22 11:44 AM
Page 20
OPERATING PROCEDURE
PHOTOS
3. Removing the electrical box
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Disconnect the connector of the indoor coil thermistor.
(4) Disconnect the motor connector (CN211 and CN121) and
the vane motor connector (CN151) on the electronic
control P.C. board.
(5) Remove the screws of ground wire.
(6) Remove the fan motor lead wire and indoor coil thermistor
from the electrical box.
(7) Remove the lead wire of vane motor from the bottom of
electrical box.
(8) Remove the screw fixing the electrical box and remove the
electrical box.
Photo 3
4. Removing the vane motor
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Remove the lead wire of vane motor.(Refer to 3.)
(4) Remove the R.L. holder.
(5) Pull out the drain hose from the nozzle assembly and
remove the nozzle assembly.
(6) Remove the screws of the vane motor and disconnect the
connector.
(7) Remove the vane motor.
Photo 4
Screws of the ground wire
Screw of the
electrical cover
Screw of the
electrical box
Vane motors
Photo 5 Screws of the
vane motor
Vane motor
5. Removing the line flow fan and the indoor fan motor
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical box. (Refer to 3.)
(3) Pull out the drain hose from the nozzle assembly and
remove the nozzle assembly.
(4) Remove the water cut.
(5) Slide the hole cover and remove the hole cover.
(6) Remove the hexagon socket set screw from the line flow
fan.
(7) Remove the screws fixing the fan motor and remove the
fan motor. (Be careful not to drop the fan motor because it
is heavy.)
(8) Remove the screws fixing the left side of the heat
exchanger.
(9) Lift the left side of the heat exchanger.
(10) Remove the line flow fan.
Photo 8
Photo 6
Screws fixing
the left side
of the heat
exchanger
Photo 7
Indoor
coil
thermistor
Water cut
Hole
cover
Screws fixing the fan motor
20
Screws
of the
vane
motor
OB345-1.qxp
04.4.23 9:27 AM
10
Page 21
PARTS LIST
MSZ-A18YV - E1 (WH)
MSZ-A24YV - E1 (WH)
MSZ-A26YV - E1 (WH)
10-1. INDOOR UNIT STRUCTURAL PARTS
10-2. INDOOR UNIT HEAT EXCHANGER
1
2
10
3
8
4
CATCH
Optional parts
(See page 23.)
5
SCREW
CAP
11
12
6
7
10-1. INDOOR UNIT STRUCTURAL PARTS
Part number that is circled is not shown in the illustration.
No.
1
2
3
4
5
6
7
8
9
Part No.
E02
E02
E02
E02
E02
E02
E02
E02
E02
527
527
851
408
527
851
534
527
851
970
234
000
142
067
010
100
975
007
Part Name
Symbol
in Wiring
Diagram
INSTALLATION PLATE
BOX (WH)
FRONT PANEL ASSEMBLY(WH)
CATCH
SCREW CAP (WH)
GRILLE (WH)
CATECHIN AIR FILTER
CORNER BOX RIGHT
LAMP PANEL
Q'ty/unit
MSZ-A18
YV - E1
(WH)
MSZ-A24
YV - E1
(WH)
MSZ-A26
YV - E1
(WH)
1
1
1
4
3
1
2
1
1
1
1
1
4
3
1
2
1
1
1
1
1
4
3
1
2
1
1
1
1
Remarks
Including No.4,5,6
4PCS/ SET
3PCS/ SET
10-2. INDOOR UNIT HEAT EXCHANGER
E02
E02
E02
11
E02
E02
12
E02
10
851
819
179
138
151
527
620
620
667
666
667
667
INDOOR HEAT EXCHANGER
INDOOR HEAT EXCHANGER
UNION (GAS)
UNION (GAS)
UNION (LIQUID)
UNION (LIQUID)
1
1
1
1
1
1
1
21
{12.7
{15.88
{6.35
{9.52
OB345-1.qxp
04.4.22 11:44 AM
Page 22
MSZ-A18YV - E1 (WH)
MSZ-A24YV - E1 (WH)
MSZ-A26YV - E1 (WH)
10-4. ACCESSORY AND
REMOTE CONTROLLER
10-3. INDOOR UNIT FUNCTIONAL PARTS AND
ELECTRICAL PARTS
1
20
19
23
24
2
3
SLEEVE
BEARING
4
11
18
12
5
6
14
ROOM
TEMPERATURE
THERMISTOR
13
10
7
FUSE
8
9
VARISTOR
17
15 16
10-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS
Part numbers that are circled are not shown in the illustration.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Part No.
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
E02
527
408
001
408
527
527
527
127
817
527
817
527
448
408
817
527
528
527
851
852
853
527
819
851
527
528
529
302
509
504
702
235
040
041
382
385
034
300
300
303
303
333
333
329
468
452
452
452
308
375
307
307
034
034
Part Name
Symbol
in Wiring
Diagram
LINE FLOW FAN
BEARING MOUNT
SLEEVE BEARING
DRAIN HOSE
NOZZLE (WH)
VANE UPPER (WH)
VANE LOWER (WH)
F11
FUSE
NR11
VARISTOR
VANE CRANK SET
MF
INDOOR FAN MOTOR ASSEMBLY
MF
INDOOR FAN MOTOR ASSEMBLY
VANE MOTOR (VERTICAL)
MV2
VANE MOTOR (HORIZONTAL)
MV1
MOTOR BAND
MOTOR BAND
DISPLAY P.C. BOARD
RECEIVER P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
RT11
ROOM TEMPERATURE THERMISTOR
TERMINAL BLOCK
TB
RT12, RT13
INDOOR COIL THERMISTOR
RT12, RT13
INDOOR COIL THERMISTOR
VANE MOTOR SUPPORT SET(RIGHT)
VANE MOTOR SUPPORT SET(LEFT)
Q'ty/unit
MSZ-A18
YV - E1
(WH)
MSZ-A24
YV - E1
(WH)
MSZ-A26
YV - E1
(WH)
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
2
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Remarks
3.15A
RC4V32 Including RUBBER MOUNT
RC4V40 Including RUBBER MOUNT
RIGHT & LEFT
UP & DOWN
AUTO RESTART
Including No.16
AUTO RESTART
Including No.16
AUTO RESTART
Including No.16
10-4. ACCESSORY AND REMOTE CONTROLLER
23 E02 529 426
24 E02 527 083
REMOTE CONTROLLER
REMOTE CONTROLLER HOLDER
22
KP0A
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11
Page 23
OPTIONAL PARTS
AIR CLEANING FILTER
● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity.
● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible.
● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet.
● DO NOT reuse AIR CLEANING FILTER even if it is washed.
● DO NOT remove or attach AIR CLEANING FILTER during unit operation.
Model
Part No.
MSZ-A18YV - E1
MSZ-A24YV - E1
MSZ-A26YV - E1
MAC-1700FT
Air cleanig filter (White bellows type)
23
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Page 24
HEAD OFFICE: MITSUBISHI DENKI BLDG.,2-2-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN
C Copyright 2004 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Apr. 2004. No.OB345 6
Made in Japan
New publication, effective Apr. 2004
Specifications subject to change without notice.