Mitsubishi Electric Mr. Slim MSZ-A09NA User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································4
4. OUTLINES AND DIMENSIONS ·························6
5. WIRING DIAGRAM ············································8
6. REFRIGERANT SYSTEM DIAGRAM················9
7. SERVICE FUNCTIONS ····································10
8. TROUBLESHOOTING······································11
9. DISASSEMBLY INSTRUCTIONS ····················25
10. PARTS LIST······················································30
10-1. PARTS LIST·············································30
10-2. RoHS PARTS LIST··································36
11. MICROPROCESSOR CONTROL·····················42
Wireless type
Models
MSZ-A09NA
MSZ-A12NA
MSZ-A15NA
MSZ-A17NA
MSZ-A24NA
MSY-A15NA
MSY-A17NA
MSY-A24NA
No. OB450
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
MSZ-A09NA MSY-A15NA
MSZ-A12NA MSY-A17NA
MSZ-A15NA
MSZ-A17NA
INDOOR UNIT
Outdoor unit service manual
MUZ-A·NA Series (OB451)
MXZ-A·NA Series (OB444)
NOTE:
This service manual describes technical data of the intdoor units.
RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the PARTS
LIST (RoHS compliant).
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1TECHNICAL CHANGES
MSZ09UN ➔MSZ-A09NA
MSZ12UN ➔MSZ-A12NA
MSH15TN ➔MSZ-A15NA
MSH17TN ➔MSZ-A17NA
MSH24WN ➔MSZ-A24NA
MS15TN ➔MSY-A15NA
MS17TN ➔MSY-A17NA
MS24WN ➔MSY-A24NA
1.Control method between indoor and outdoor has been changed.
2.Indoor fan motor has been changed.
3.Signal of remote controller has been changed. (It is not available for conventional models.)
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3
PART NAMES AND FUNCTIONS
2
MSZ-A09NA MSY-A15NA
MSZ-A12NA MSY-A17NA
MSZ-A15NA
MSZ-A17NA
MSZ-A24NA
MSY-A24NA
MSZ-A09NA
MSZ-A12NA
MSZ-A15NA
MSZ-A17NA
MSY-A15NA
MSY-A17NA
Line flow fan
Air outlet
Vertical vane
Air inlet
Display section
Front panel
Panel Heat exchanger
Horizontal vane
Operation section
(When the front panel is opened)
Remote controller
Remote control
receiving section
Catechin air filter
Air cleaning filter
(Anti-Allergy Enzyme
Filter, Blue bellows
type)
Emergency operation switch
Emergency operation switch
Operation indicator lamp
Remote control
receiving section
Operation Indicator
lamp
MSZ-A24NA
MSY-A24NA
ACCESSORIES
1
2
3
4
5
6
7
8
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 3o3.5 o1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Conduit plate
1
7
1
2
2
1
1
–
1
8
1
2
2
1
1
1
MSZ-A24NA
MSY-A24NA
MSZ-A09NA MSZ-A17NA
MSZ-A12NA MSY-A15NA
MSZ-A15NA MSY-A17NA
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3SPECIFICATION
NOTE : Test conditions are based on ARI 210/240.
❈1 : Rating conditions(cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 95˚FDB, (75˚FWB)
(heating) — Indoor : 70˚FDB, 60˚FWB, Outdoor : 47˚FDB, 43˚FWB
❈2 : (heating) — Indoor : 70˚FDB, 60˚FWB, Outdoor : 17˚FDB, 15˚FWB
Item Model MSZ-A12NA
INDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)/ Disconnect switch
Min. circuit ampacity
Fan motor
Airflow Low—Med.—High
Moisture removal
Sound level Low-Med.-High
Cond. drain connection O.D.
Dimensions
Weight
REMOTE CONTROLLER
Control voltage (by built-in transformer)
V, phase, Hz
A
A
F.L.A
CFM
CFM
pt./h
dB(A)
in.
in.
in.
in.
Ib.
MSZ-A12NA
1.0
0.76
353-240-159
353(318)-240(215)-152(134)
3.2
22-34-42
23
MSZ-A09NA
1.0
0.76
307-222-159
307(275)-229(205)-152(134)
2.3
22-33-38
23
White
208/230, 1, 60
15
5/8
30-11/16
8-1/4
11-3/4
Wireless type
12-24V DC
MSZ-A09NA
HEAT Dry
COOL Dry (Wet)
W
D
H
Item Model MSZ-A17NA MSY-A17NA
INDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)/ Disconnect switch
Min. circuit ampacity
Fan motor
Airflow Low—Med.—High
Moisture removal
Sound level Low-Med.-High
Cond. drain connection O.D.
Dimensions
Weight
REMOTE CONTROLLER
Control voltage (by built-in transformer)
V, phase, Hz
A
A
F.L.A
CFM
CFM
pt./h
dB(A)
in.
in.
in.
in.
Ib.
1.0
0.76
381(342)-328(293)-268(240)
5.1
23
1.0
0.76
381(342)-328(293)-268(240)
4.7
23
381-314-254
34-40-45/34-38-44
—
34-40-45/ —
381-314-254
34-40-46/34-38-44
—
34-40-46/ —
White
208/230, 1, 60
15
5/8
30-11/16
8-1/4
11-3/4
Wireless type
12-24V DC
MSZ-A15NA MSY-A15NA
HEAT Dry
COOL Dry (Wet)
W
D
H
HEAT Dry
COOL Dry (Wet)
W
D
H
Item Model MSY-A24NA
INDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)/ Disconnect switch
Min. circuit ampacity
Fan motor
Airflow Low—Med.—High
Moisture removal
Sound level Low-Med.-High
Cond. drain connection O.D.
Dimensions
Weight
REMOTE CONTROLLER
Control voltage (by built-in transformer)
V, phase, Hz
A
A
F.L.A
CFM
CFM
pt./h
dB(A)
in.
in.
in.
in.
Ib.
MSY-A24NA
1.0
0.76
—
568(508)-431(385)-296(265)
7.3
34-40-49/ —
37
MSZ-A24NA
1.0
0.76
568-486-296
568(508)-431(385)-296(265)
7.3
34-40-49/34-40-48
37
White
208/230, 1, 60
15
5/8
43-5/16
10-1/4
12-13/16
Wireless type
12-24V DC
MSZ-A24NA
(Cooling/Heating)
(Cooling/Heating)
MSZ-A15NA MSY-A15NA MSZ-A17NA MSY-A17NA
-
-
-
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5
MSZ-A09NA
MSZ-A12NA
MSZ-A15NA
MSZ-A15NA
MSY-A15NA
MSZ-A17NA
MSZ-A17NA
MSY-A17NA
MSZ-A24NA
MSZ-A24NA
MSY-A24NA
Model Mode
HEAT
COOL
HEAT
COOL
HEAT
COOL
HEAT
COOL
HEAT
COOL
307
307
275
353
353
318
381
381
342
381
381
342
568
568
508
16.8
16.8
15.1
19.3
19.3
17.4
20.9
20.9
18.8
20.9
20.9
18.8
20.2
20.2
18.1
23.4
23.4
21.0
26.7
26.7
24.1
28.8
28.8
26.0
28.8
28.8
26.0
34.4
34.4
30.9
Air flow
(CFM) Air speed (ft./sec.) Coverage range (ft.)
Function
Dry
Dry
Wet
Dry
Dry
Wet
Dry
Dry
Wet
Dry
Dry
Wet
Dry
Dry
Wet
3-1. OPERATING RANGE
(1) POWER SUPPLY
MSZ-A09NA MSY-A15NA
MSZ-A12NA MSY-A17NA
MSZ-A15NA MSY-A24NA
MSZ-A17NA
MSZ-A24NA
Rated voltage Guaranteed VoltageModel
Min. 198V Max. 253V
208V 230V
208/230V 1phase 60Hz
3-2. OUTLET AIR SPEED AND COVERAGE RANGE
(2) OPERATION
78% —
Function
Cooling
Heating
Standard temperature
Maximum temperature
Minimum temperature
Maximum humidity
Standard temperature
Maximum temperature
Minimum temperature
DB (˚F)
80
95
67
70
80
70
WB (˚F)
67
71
57
60
67
60
Indoor
DB (˚F)
95
115
14
47
75
14
WB (˚F)
—
—
—
43
65
13
Outdoor
Condition
Intake air
temperature
●The air coverage range is the figure up
to the position where the air speed is 1
ft./sec., when air is blown out horizon-
tally from the unit properly at the High
speed position.
The coverage range should be used
only as a general guideline since it
varies according to the size of the room
and furniture arranged inside the room.
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4OUTLINES AND DIMENSIONS
Unit : inch
11-3/4
424-9/16
30-11/16
8-1/4 3/16
2-1/8
3/4
6-1/4
2-5/16
Air in
Air out
Installation plate
Insulation [1-1/8
Drain hose [5/8
(Connected part O.D)
Liquid line [1/4 19-11/16
Gas line [3/8 16-15/16
Insulation [1-3/8 O.D
[3/4 I.D
{
6-1/8 6-1/8
7/8
1-3/4
13-3/16 12-5/8
1-5/8 8-7/16
10-1/8
1-11/16
8-7/16
1/8 11-5/16
2-3/4
2-3/16
2-3/16 2-3/16
8-7/8 8-7/8
9/1610-3/4
9-3/16
Wall hole [2-9/16
Indoor unit
Installation plate
7/16x13/16 Oblong hole
7/16x1 Oblong hole
7/8
hole
MSZ-A09NA MSY-A15NA
MSZ-A12NA MSY-A17NA
MSZ-A15NA
MSZ-A17NA
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10-1/4
6-1/4
3/4
2-5/16
1-7/8
5/16
12-3/8
10-1/161-7/8
1/8
3-7/8
6-13/16
3-7/8 6-13/16 16-5/16 16-5/16
3/16
9-15/16
31-1/8
2-3/16
42-1/16
43-5/16
12-13/16
Air out
Air in
Insulation [1-1/8
Drain hose [5/8
(Connected part O.D)
Installation plate
Wall hole [3
Wireless remote controller
Installation plate Indoor unit
{
Liquid line [1/4 19-11/16
Gas line [5/8 16-15/16
Insulation [1-15/16 O.D
[1-1/4 I.D
MSZ-A24NA
MSY-A24NA Unit : inch
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5WIRING DIAGRAM
MSZ-A09NA MSY-A15NA
MSZ-A12NA MSY-A17NA
MSZ-A15NA
MSZ-A17NA
MSZ-A24NA
MSY-A24NA
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REFRIGERANT SYSTEM DIAGRAM
6
MSZ-A09NA
MSZ-A12NA
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Flared connection
Refrigerant pipe [3/8
(with heat insulator)
Refrigerant pipe [1/4
(with heat insulator)
Indoor coil
thermistor
RT12(main)
Refrigerant flow in cooling
Refrigerant flow in heating
MSZ-A15NA MSY-A15NA
MSZ-A17NA MSY-A17NA
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [1/2
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12(main)
Refrigerant pipe[1/4
(with heat insulator)
Distributor
MSZ-A24NA
MSY-A24NA
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [5/8
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12(main)
Refrigerant pipe [1/4
(with heat insulator)
Distributor
Unit:inch
Indoor coil
thermistor
RT13(sub)
Indoor coil
thermistor
RT13(sub)
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7SERVICE FUNCTIONS
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.
7-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS the indoor electronic control P.C. board.
The time will be shortened as follows. (Refer to 8-7.)
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.)
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 accept 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 the RESET button.
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.
J2
J1
MSZ-A09NA MSZ-A12NA MSZ-A15NA MSZ-A17NA MSZ-A24NA
MSY-A15NA MSY-A17NA MSY-A24NA
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
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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 turn off the unit first with the remote controller, 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.
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 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.
JR07
CN151 CN211CN112
BZ
7-3. 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.
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 of the unit.
2Solder the Jumper wire JR07 on the indoor electronic control P.C. board. (Refer to 8-7.)
JR07
CN151
CN152
CN101
CN211CN112
BZ
MSZ-A24NA
MSY-A24NA
MSZ-A09/12/15/17NA
MSY-A15/17NA
Housing point
Lead wiring
TROUBLESHOOTING
8
MSZ-A09NA MSZ-A12NA MSZ-A15NA MSZ-A17NA MSZ-A24NA
MSY-A15NA MSY-A17NA MSY-A24NA
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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 discoloration.
4) When troubleshooting, refer to 8-2., 8-3. and 8-4.
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
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.
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.
Operation indicator lamp flashes as shown in the figure below.
•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.
OPERATION INDICATOR
Not lighted
Blinking
Lighted
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Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (8-4.) disappears, the memorized failure details
can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
8-2. Failure mode recall function
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Operational procedure
Yes
(Blinks)
No
(OFF)
Yes
No
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.
W2. Blinking pattern when the indoor unit is abnormal:
W3.Blinking pattern when the outdoor unit is abnormal:
ON
OFF Beeps
Repeated cycle Repeated cycle
ON
OFF No beep Beeps
Repeated cycle
2.5-second OFF Blinking at 0.5-
second interval
2.5-second OFF 3-second ON Blinking at 0.5-
second interval
Beeps Repeated cycle
2.5-second OFF Blinking at 0.5-
second interval
No beep Beeps
Repeated cycle
2.5-second OFF 3-second ON Blinking at 0.5-
second interval
Repeated cycle
Beeps
Does the left lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep are emitted at the same timing
as the blinking of the left lamp of
OPERATION INDICATOR lamp. W2
The cause of abnormality cannot be found because the abnormality doesn't recur.
Setting up the failure mode recall function
Before blinking, does the left lamp of
OPERATION INDICATOR lamp stay ON for 3
seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
The indoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the indoor unit
failure mode table(8-2.2.).
Make sure to check at least two consecutive blinking cycles. W2
Turn ON the power supply.
<Preparation of the remote controller>
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 after all LCD in operation display section of the
remote controller is displayed after 3 seconds.
Deleting the abnormal memorized condition
1After repairing the unit, recall the failure mode again according to
"Setting up the failure mode recall function" mentioned above.
2Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit.
3Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
4Release 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.
• Turn OFF the power supply and turn it ON again.
• Press RESET button of the remote controller.
Judgment of indoor/outdoor abnormality
Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. W1
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some
abnormalities that can't be recalled with this way.
Confirm if outdoor unit is abnormal according to the detailed outdoor
unit failure mode recall function.
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the
outdoor unit failure mode table (Refer to outdoor unit service manual.)
Make sure to check at least two consecutive blinking cycles. W3
W1. Regardless of normal or abnormal, a short
beep is emitted once as the signal is received.
This figures show about MSZ-A09/12/15/17.
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2. Indoor unit failure mode table
NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (8-4.).
12-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.
11-time flash
2.5-second OFF Refer to 8-6.A"Check of indoor fan
motor".
Indoor fan motor When the rotational frequency feedback
signal is not emit during the 12-seconds the
indoor fan operation.
2-time flash
2.5-second OFF
Refer to the characteristics of the main
indoor coil thermistor, the sub indoor coil
thermistor (8-7.).
Indoor coil thermistor When the indoor coil thermistor short or open
circuit is detected every 8 seconds during
operation.
3-time flash
2.5-second OFF Refer to 8-6.D"How to check mis-wiring
and serial signal error".
Serial signal When the serial signal from outdoor unit is
not received for a maximum of 6 minutes.
1-time flash
every 0.5-second Refer to the characteristics of the room
temperature thermistor (8-7.).
Room temperature
thermistor
When the room temperature thermistor short
or open circuit is detected every 8
seconds during operation.
Not lighted –Normal –
Left lamp of OPERATION
INDICATOR lamp
Correspondence
Abnormal point
(Failure mode) Condition
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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 only
in Test Run
operation.
w
Outdoor unit
doesn't
operate
even in
Test Run
operation.
w
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 8-7.
"Test point
diagram and
voltage".
Refer to
"How to check
inverter/
compressor".
Refer to 8-6.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 8-6.C
"Check of indoor
electronic control
P.C. board and indoor
fan motor".
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 8-6.
D "How to
check of
mis-wiring
and serial
signal error
".
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to 8-7.
"Test point
diagram and
voltage".
Refer to 8-6.
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
14-time flash
Cause:
Outdoor unit
• Other
abnormality
Check
"Flow chart of
the detailed
outdoor unit
failure mode
recall function."
Left lamp
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
Refer to outdoor unit service manual.
Indoor unit operates.
Outdoor unit doesn't
operate normally.
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked with
failure mode recall function.
w
"Test Run operation" means the
operation within 30 minutes after
EMERGENCY OPERATION switch
is pressed.
8-3. Instruction of troubleshooting
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16
No.
1
3
6
7
SymptomOperation indicator lamp Condition Correspondence
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
When the serial signal from the outdoor unit is
not received for a maximum of 6 minutes.
When it consecutively occurs 3 times that the
compressor stops for overcurrent protection or
start-up failure protection within 1 minute after
start-up.
When the outdoor thermistors short or open
circuit during the compressor operation.
When it cannot properly read data in the
nonvolatile memory of the inverter P.C. board
or the outdoor electronic control P.C. board.
• Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
• Refer to "How to check of
inverter/ compressor".
Refer to outdoor unit service
manual.
• Check the stop valve.
• Replace the inverter P.C.
board or the outdoor
electronic control P.C. board.
Refer to outdoor unit service
manual.
• Refer to 8-6.D"How to check
mis-wiring and serial signal
error".
4Indoor fan
motor
8
Abnormal
point
Room
tempera-
ture
thermistor
Left lamp flashes.
2-time flash
2.5-second OFF
When the indoor coil or the room temperature
thermistor is short or open circuit. • Refer to 8-7.the
characteristics of indoor coil
thermistor, and the room
temperature thermistor.
Left lamp flashes.
3-time flash
2.5-second OFF
When the rotational frequency feedback
signal is not emitted during the indoor fan
operation. • Refer to 8-6.A"Check of
indoor fan motor".
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Left lamp flashes.
5-time flash
2.5-second OFF
Left lamp flashes.
6-time flash
2.5-second OFF
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Other
abnormality
An abnormality other than above mentioned is
detected.
• Confirm the abnormality in
detail using the failure mode
recall function for outdoor
unit.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
9
5
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.
Indoor unit
and outdoor
unit do not
operate.
•Replace the indoor electronic
control P.C. board.
Outdoor
control
system When it cannot properly read data in the
nonvolatile memory of the inverter P.C. board
or the outdoor electronic control P.C. board.
• Check the blinking pattern of
the LED on the inverter P.C.
board or the outdoor
electronic
control P.C. board.
2Outdoor unit
does not
operate.
Left lamp lights up
MSZ-A09/12
MSZ-A15/17
MSY-A15/17
Left lamp flashes.
7-time flash
2.5-second OFF
Left lamp flashes.
14-time flash
2.5-second OFF
8-4. Troubleshooting check table
Not lighted
Blinking
OPERATION INDICATOR
Lighted
· Flashing of OPERATION INDICATOR lamp (left-hand side lamp)
indicates abnormalities.
Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and the following 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
OPERATION INDICATOR lamp flashing.
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17
OPERATION INDICATOR
Not lighted
Blinking
Lighted
No. SymptomOperation indicator lamp Condition Correspondence
Abnormal
point
1
MXZ type
Operation
mode
setting
Outdoor unit
operates but
indoor unit
does not
operate.
When the operation mode of the each indoor
unit is differently set to COOL(includes DRY)
and HEAT at the same time, the operation
mode of the indoor unit that has operated at
first has the priority.
• Unify the operation mode.
Refer to outdoor unit service
manual.
2.5-second OFF
Right lamp flash
· Flashing of OPERATION INDICATOR lamp (right-hand side lamp) indicates
abnormality.
· OPERATION INDICATOR lamp (left-hand side lamp) is lighted.
8-5. Trouble criterion of main parts
Part name FigureCheck method and criterion
Indoor fan motor(MF)
Measure the resistance with a tester.
Refer to 8-7. "Test point diagram and voltage",
"Indoor electronic control P.C. board", the chart of thermistor.
Room temperature
thermistor(RT11)
Indoor coil thermistor
(RT12(MAIN), RT13(SUB))
Horizontal vane
motor(MV)
MSZ-A09/12/15/17NA
MSY-A15/17NA Normal
BRN-other one
Measure the resistance between the terminals with a tester.
(Part temperature 50°F ~ 86°F)
235 "~ 255 "

Color of the lead wire
Check 8-6. A.
Horizontal vane
motor(MV1)
Vertical vane
motor(MV2)
MSZ-A24NA
MSY-A24NA
Normal
BRN-other one
Measure the resistance between the terminals with a tester.
(Part temperature 50°F ~ 86°F)
282 "~ 306 "

Color of the lead wire
RED
YLW
BRN
ORN GRN
ROTOR
RED
YLW
BRN
ORN GRN
ROTOR
MSZ-A09NA MSZ-A12NA MSZ-A15NA
MSZ-A17NA MSZ-A24NA
MSY-A15NA MSY-A17NA MSY-A24NA
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18
Check of indoor fan motor
A
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan does not operate.
w If more than 12 seconds or more passes after EMERGENCY OPERATION
switch is pressed, the voltage mentioned above 2 goes 0V DC although
the indoor electric control P.C. board is normal.
Indoor electronic
control P.C. board
Pay careful attention to the high voltage on
the fan motor connector CN211.
Yes
No
No
No
(Changed)
Yes
(Unchanged)
Is there any foreign matter that
interferes the rotation of the
line flow fan?
Turn OFF the power supply.
Remove the foreign matter and
adjust the line flow fan.
Turn ON the power supply, wait 5 seconds or more, and then press
EMERGENCY OPERATION switch.
Measure the supply voltage as follows within 12 seconds
after EMERGENCY OPERATION switch is pressed.
If more than 12 seconds passes by, turn OFF the power supply and
turn ON it again, then measure the voltage. w
1.Measure the voltage between CN211 1(+) and 3(-).
2.Measure the voltage between CN211 5(+) and 3(-).
Is there 294/325V DC between
CN211 1(+) and 3(-), and does
the voltage between CN211 5(+)
and 3(-) rise to the range of 3 to 6V
DC within 12 seconds after
EMERGENCY OPERATION switch
is pressed?
Yes Replace the indoor fan motor.
CN211
Replace the indoor electronic control P.C. board.
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3times, and then stops.
Measure the voltage between CN211
6(+) and 3(-) while the fan
motor is rotating.
Is it unchanged holding
0V DC or 15V DC?
Replace the indoor fan motor.
Replace the indoor electronic control P.C. board.
The indoor fan motor error has occurred, and the indoor fan doesn't operate.
8-6. Troubleshooting flow
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19
Check of remote controller and receiver P.C. board
B
Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller.
wCheck if the remote controller is exclusive for this air conditioner.
Yes
Replace the batteries. (Refer to 8-1.4.)
Turn ON a radio to AM and press switch
ON the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 3.28ft.?
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 8-1.4.)
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
Replace the receiver P.C. board.
Measure the voltage between receiver P.C. board
connector CN301 No.2(+) and No.3(-) when the
remote controller button is pressed.
Is the voltage approx. 4V DC? Replace the indoor electronic control P.C.
board.
No (5V or 0V DC)
Yes
MSZ-A09/12/15/17NA
MSY-A15/17NA
MSZ-A24NA
MSY-A24NA
No
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