CONTENTS
1. TECHNICAL CHANGES ······························2
2. PART NAMES AND FUNCTIONS ··················3
3. SPECIFICATION ········································4
4. OUTLINES AND DIMENSIONS ·····················6
5. WIRING DIAGRAM ·····································7
6. REFRIGERANT SYSTEM DIAGRAM ·············8
7. SERVICE FUNCTIONS ································9
8. MICROPROCESSOR CONTROL ················ 11
9. TROUBLESHOOTING ······························· 19
10. DISASSEMBLY INSTRUCTIONS ················· 31
SERVICE MANUAL
INDOOR UNIT
PARTS CATALOG (OBB736)
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
No. OBH736
Models
MSZ-EF09NAW
-
U1
MSZ-EF12NAW
-
U1
MSZ-EF15NAW
-
U1
MSZ-EF18NAW
-
U1
MSZ-EF09NAB
-
U1
MSZ-EF12NAB
-
U1
MSZ-EF15NAB
-
U1
MSZ-EF18NAB
-
U1
MSZ-EF09NAS
-
U1
MSZ-EF12NAS
-
U1
MSZ-EF15NAS
-
U1
MSZ-EF18NAS
-
U1
Outdoor unit service manual
MXZ- ∙C∙NA(HZ) Series (OCH573)
2
TECHNICAL CHANGES
1
Use the specifi ed refrigerant only
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the spec labels provided with our products.
We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by
failure to follow the instructions.
MSZ-EF09NAW -
U1
MSZ-EF12NAW -
U1
MSZ-EF15NAW -
U1
MSZ-EF18NAW -
U1
MSZ-EF09NAB -
U1
MSZ-EF12NAB -
U1
MSZ-EF15NAB -
U1
MSZ-EF18NAB -
U1
MSZ-EF09NAS -
U1
MSZ-EF12NAS -
U1
MSZ-EF15NAS -
U1
MSZ-EF18NAS -
U1
1. New model
OBH736
3
PART NAMES AND FUNCTIONS
2
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
ACCESSORIES
Model
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Installation plate 1
Installation plate fi xing screw 4 × 25 mm 5
Remote controller holder 1
Fixing screw for 3.5 × 16 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
Soft dry cloth (NAB type only) 1
Air cleaning fi lter 2
Remote controller
Operation
indicator lamp
Remote control
receiving section
Emergency
operation switch
Horizontal vane
Air inlet
Air ¿ lter
(Nano platinum ¿ lter)
Air cleaning ¿ lter
(Electrostatic anti-allergy
enzyme ¿ lter)
Heat exchanger
Front panel
Air outlet
OBH736
4
SPECIFICATION
3
(2) OPERATION
Mode Condition
Intake air temperature (°F)
Indoor Outdoor
DB WB DB WB
Cooling
Standard temperature 80 67 95 —
Maximum temperature 90 73 115 —
Minimum temperature 67 57 14 —
Maximum humidity 78% —
Heating
Standard temperature 70 60 47 43
Maximum temperature 80 67 75 65
Minimum temperature 70 60 -13 -14
3-1. OPERATING RANGE
(1) POWER SUPPLY
Rated voltage Guaranteed voltage (V)
Indoor unit
208/230 V
1 phase
60 Hz
Min. 187
208 230 Max. 253
Indoor unit model
MSZ-EF09NAW
MSZ-EF09NAB
MSZ-EF09NAS
MSZ-EF12NAW
MSZ-EF12NAB
MSZ-EF12NAS
MSZ-EF15NAW
MSZ-EF15NAB
MSZ-EF15NAS
MSZ-EF18NAW
MSZ-EF18NAB
MSZ-EF18NAS
Power supply V, phase, Hz 208/230 , 1 , 60
Disconnect switch A 15
Min. circuit ampacity A 1.0
Fan motor F.L.A 0.67
Airfl ow
Super high - High - Med. - Low - Quiet
COOL Dry
(Wet)
CFM
371 - 293 - 222 - 162 - 141
(319 - 252 - 191 - 140 - 121)
371 - 293 - 222 - 162 - 141
(319 - 252 - 191 - 140 - 121)
364 - 314 - 272 - 233 - 205
(313 - 270 - 234 - 200 - 176)
388 - 328 - 279 - 240 - 205
(334 - 282 - 240 - 206 - 176)
HEAT Dry CFM
420 - 314 - 219 - 162 - 141 448 - 314 - 219 - 162 - 141 448 - 350 - 275 - 222 - 194 466 - 392 - 318 - 258 - 226
Moisture removal pt./h 0.6 2.1 3.6 4.4
Sound level
Super high - High - Med. - Low - Quiet
Cooling dB(A)
42 - 36 - 29 - 23 - 21 42 - 36 - 29 - 24 - 21 42 - 39 - 35 - 31 - 28 43 - 40 - 36 - 33 - 30
Heating dB(A)
45 - 37 - 29 - 24 - 21 46 - 38 - 30 - 24 - 21 48 - 41 - 35 - 30 - 28 49 - 43 - 37 - 33 - 30
Cond. drain connection O.D. in. 5/8
Dimensions
W
in.
34-13/16
D 7-11/16
H 11-3/4
Weight Ib. 26
External fi nish
W: Munsell 1.0Y 9.2/0.2
B: Munsell 3.7PB 2.0/0.1
S: Munsell 3.1PB 8.2/0.2
Remote controller Wireless type
Control voltage (by built-in transformer) 12 - 24 VDC
NOTE: Test conditions are based on AHRI 210/240.
OBH736
5
3-2. OUTLET AIR SPEED AND COVERAGE
● The air coverage is the figure up to the
position where the air speed is 1 ft./s,
when air is blown out horizontally from
the unit properly at the High speed
position.
The coverage should be used only
as a general guideline since it varies
according to the size of the room and
furniture arranged inside the room.
Model Mode Function
Airfl ow
(CFM)
Air speed
(ft./s)
Coverage
(ft.)
MSZ-EF09NAW
MSZ-EF09NAB
MSZ-EF09NAS
HEAT Dry 420 19.5 29.2
COOL
Dry 371 17.2 25.8
Wet 319 15.5 23.3
MSZ-EF12NAW
MSZ-EF12NAB
MSZ-EF12NAS
HEAT Dry 448 20.8 31.1
COOL
Dry 371 17.2 25.8
Wet 319 15.5 23.3
MSZ-EF15NAW
MSZ-EF15NAB
MSZ-EF15NAS
HEAT Dry 448 20.8 31.1
COOL
Dry 364 16.8 25.4
Wet 313 15.2 22.9
MSZ-EF18NAW
MSZ-EF18NAB
MSZ-EF18NAS
HEAT Dry 466 21.6 32.3
COOL
Dry 388 20.3 30.4
Wet 336 18.3 27.4
OBH736
6
Unit: inch
OUTLINES AND DIMENSIONS
4
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
MSZ-EF09/12NA MSZ-EF15/18NA
OBH736
7
WIRING DIAGRAM
5
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
OBH736
8
Unit: inch (mm)
REFRIGERANT SYSTEM DIAGRAM
6
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe ø3/8 (ø9.52) (MSZ-EF09/12)
ø1/2 (ø12.7) (MSZ-EF15/18)
(with heat insulator)
Refrigerant pipe ø1/4 (ø6.35)
(with heat insulator)
Indoor coil
thermistor
RT12 (main)
Indoor coil
thermistor
RT13 (sub)
Refrigerant flow in cooling
Refrigerant flow in heating
OBH736
9
7-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging JPG and JPS on the electronic control P.C. board.
(Refer to 9-7.)
• The set time for the ON/OFF timer can be reduced to 1 second for each minutes.
• After the breaker is turned on, the time for starting the compressor, which normally takes 3 minuets, can be reduced to
3 seconds. Restarting the compressor, which takes 3 minuets, cannot be reduced.
7-2. HOW TO SET REMOTE CONTROLLER EXCLUSIVELY FOR A PARTICULAR INDOOR UNIT
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
To operate the indoor units individually with each remote controller, assign a number to each remote controller according
to the number of the indoor unit.
This setting can be set only when all the following conditions are met:
• The remote controller is powered OFF.
• Weekly timer is not set.
• Weekly timer is not being edited.
(1) Hold down
button on the remote controller for 2 seconds to enter the pairing mode.
(2) Press
button again and assign a number to each remote controller.
Each press of
button advances the number in the following order: 1 → 2 → 3 → 4.
(3) Press
button to complete the pairing setting.
After you turn the breaker ON, the remote controller that first sends a signal to an indoor unit will be regarded as the
remote controller for the indoor unit.
Once they are set, the indoor unit will only receive the signal from the assigned remote controller afterwards.
SERVICE FUNCTIONS
7
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
OBH736
10
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. “AUTO RESTART FUNCTION” automatically starts operation in
the same mode just before the shutoff of the main power.
Operation
If the main power has been cut, the operation settings remain.
After 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 disable “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Cut the jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 9-7.)
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 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.
JR77
IC171
CN104CN112
BZ
Indoor electronic
control P.C. board
OBH736
11
WIRELESS REMOTE CONTROLLER
MICROPROCESSOR CONTROL
8
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
INDOOR UNIT DISPLAY SECTION
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Operation Indicator lamp
The operation indicator at the right side of the indoor unit indicates the operation state.
•The following indication applies regardless of shape of the indication.
Indication Operation state Room temperature
The unit is operating to
reach the set temperature
About 4°F (2°C) or more
away from set tempera-
ture
The room temperature is
approaching the set tem-
perature
About 2 to 4°F (1 to 2°C)
from set temperature
Standby mode
(Only during multi system
operation)
-
Lighted
Blinking
Not lighted
Signal transmitting section
Operation display section
TEMPERATURE buttons
STOP/OPERATE
(OFF/ON) button
Indication of
remote controller
model is on back
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button
CLOCK SET button
WEEKLY TIMER
set button
TIME, TIMER set buttons
FORWARD button
BACKWARD button
RESET button
SMART SET button
VANE CONTROL button
OBH736
12
8-2. DRY ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select DRY mode with OPERATION SELECT button.
(3) The set temperature is determined from the initial room temperature.
1. Coil frost prevention
Coil frost prevention works the same way as that in COOL mode. (8-1.1.)
2. Low outside temperature operation
Low outside temperature operation works the same way as that in COOL mode. (8-1.2.)
3. Indoor fan speed control
Indoor fan speed control works the same way as that in COOL mode. (8-1.3.)
8-3. FAN ( ) OPERATION
(1) OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select FAN mode with OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low.
Only indoor fan operates.
Outdoor unit does not operate.
8-4. HEAT ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons TEMP
or button to select the desired temperature.
The setting range is 61 - 88°F (16 - 31°C).
1. Cold air prevention control
When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room tem-
perature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.
2. High pressure protection
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the con-
densing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
The indoor fan operates following the cold air prevention control. This mode continues until the temperature of indoor
heat exchanger falls.
3. Defrosting
Defrosting starts when the temperature of outdoor heat exchanger becomes too low.
The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.
This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.
8-1. COOL ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons TEMP
or button to select the desired temperature.
The setting range is 61 - 88°F (16 - 31°C).
1. Coil frost prevention
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil
from frosting.
When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works.
The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor
heat exchanger rises.
2. Low outside temperature operation
When the outside temperature is lower, low outside temperature operation starts, and the outdoor fan slows or stops.
3. Indoor fan speed control
When the thermostat turns OFF, the indoor fan operates very Low to reduce power consumption.
When the room temperature rises and the thermostat is ON, the indoor fan operates according to the settings on the
remote controller.
OBH736
13
8-5. AUTO CHANGE OVER ∙∙∙ AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
Mode selection
(1) Initial mode
When unit starts the operation with AUTO operation from OFF:
• If the room temperature is higher than the set temperature, operation starts in COOL mode.
• If the room temperature is equal to or lower than the set temperature, operation starts in HEAT mode.
(2) Mode change
COOL mode changes to HEAT mode when about 15 minutes have passed with the room temperature 2°F (1°C) below
the set temperature.
HEAT mode changes to COOL mode when about 15 minutes have passed with the room temperature 2°F (1°C) above
the set temperature.
NOTE 1
If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is operating in
(AUTO), cannot change over to the other operating mode (COOL ↔ HEAT) and becomes a state of standby.
Refer to NOTE 2 “FOR MULTI SYSTEM AIR CONDITIONER”.
8-6. AUTO VANE OPERATION
1. Horizontal vane
(1) Vane motor drive
These models are equipped with a stepping motors for the horizontal vanes. The rotating direction, speed, and angle
of the motor are controlled by pulse signals (approximately 12 V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
NOTE 2
FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
• When you try to operate 2 or more indoor units with one outdoor unit simultaneously, one for the cooling and the
others for heating, the operation mode of the indoor unit that operates first is selected. Other indoor units cannot
operate, and operation indicator lamp flashes as shown in the figure below. In this case, please set all the indoor
units to the same operation mode.
• When indoor unit 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 flow-
ing may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
OPERATION INDICATOR
Lighted
Blinking
Not lighted
AUTO
12345
SWING
(3) Positioning
To confirm the standard position, the vane move until it touches the vane stopper. Then the vane is set to the select-
ed angle.
Confirming of standard position is performed in the following cases:
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(c) When standby mode (only during multi system operation) starts or finishes.
OBH736
14
(7) SWING (
) mode
By selecting SWING mode with VANE CONTROL button, the horizontal vanes swing vertically.
When COOL, DRY or FAN mode is selected, only the upper vane swings.
(8) Cold air prevention in HEAT operation
The horizontal vane position is set to upward.
NOTE: When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off,
this control does not work in the indoor unit.
(9) ECONO COOL (
) operation (ECONOmical operation)
When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 4°F (2°C) higher by the
microprocessor. However, the temperature on the LCD screen on the remote controller is not changed. Also the hori-
zontal vane swings in various cycle.
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher, the air
conditioner can keep comfort. As a result, energy can be saved.
To cancel this operation, select a different mode or press one of the following buttons in ECONO COOL operation:
ECONO COOL or VANE CONTROL button.
Horizontal
position
4
In COOL and DRY operation
Vane angle is fixed to Horizontal position.
In HEAT operation
Vane angle is fixed to Angle 4.
(5) STOP (operation OFF) and ON TIMER standby
In the following cases, the horizontal vane returns to the closed position.
(a) When STOP/OPERATE (OFF/ON) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 4 or 5 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 3 for dew prevention.
(4) VANE AUTO (
) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room tem-
perature distribution.
OBH736
15
8-7. TIMER OPERATION
1. How to set the time
(1) Check that the current time is set correctly.
NOTE: Timer operation will not work without setting the current time. Initially “12:00 AM” blinks at the current time
display of TIME MONITOR, so set the current time correctly with CLOCK button.
How to set the current time
(a) Press the CLOCK button.
(b) Press the TIME SET buttons (
and ) to set the current time.
• Each time FORWARD button ( ) is pressed, the set time increases by 1 minute, and each time BACKWARD
button (
) is pressed, the set time decreases by 1 minute.
• Pressing those buttons longer, the set time increases/decreases by 10 minutes.
(c) Press the CLOCK set button.
(2) Press STOP/OPERATE (OFF/ON) button to start the air conditioner.
(3) Set the time of timer.
ON timer setting
(a) Press ON TIMER button( ) during operation.
(b) Set the time of the timer using TIME SET buttons ( and ).
OFF timer setting
(a) Press OFF TIMER button (
) during operation.
(b) Set the time of the timer using TIME SET buttons (
and ).
Each time FORWARD button ( ) is pressed, the set time increases by 10 minutes: each time BACKWARD
but-
ton (
) is pressed, the set time decreases by 10 minutes.
2. To release the timer
To release ON timer, press ON TIMER button (
).
To release OFF timer, press OFF TIMER button(
).
TIMER is cancelled and the display of set time disappears.
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
• OFF timer and ON timer can be used in combination. The set time that is reached first will operate first.
• “
” and “ ” display shows the order of OFF timer and ON timer operation.
PROGRAM TIMER
(Example 2) The current time is 11:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE: If the main power is turned OFF or a power failure occurs while ON/OFF timer is active, the timer setting is can-
celled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
OBH736
16
8-8. WEEKLY TIMER OPERATION
E.g. : Runs at 75°F (24°C) from waking up to leaving home,
and runs at 81°F (27°C) from getting home to going to
bed on weekdays.
Runs at 81°F (27°C) from waking up late to going bed
early on weekends.
75°F (24°C)
81°F (27°C)
PM 5:30AM 6:00 AM 8:30 PM 10:00
PM 9:00PM 8:00
81°F (27°C)
• A maximum of 4 ON or OFF timers can be set for individual days of the week.
• A maximum of 28 ON or OFF timers can be set for a week.
NOTE:
• The simple ON/OFF timer setting is available while the weekly timer is on. In this case, the ON/OFF timer has priority over the
weekly timer; the weekly timer operation will start again after the simple ON/OFF timer is complete.
• When the weekly timer is set, temperature can not be set to 50°F (10°C).
• The weekly timer operation and SMART SET operation cannot be used together.
* Make sure that the current time and day are set correctly.
(1) Press button to enter the weekly timer setting mode.
(2) Press
and buttons to select setting day and number.
(3) Press , , and buttons to set ON/OFF, time, and temperature.
E.g. : [ON], [AM 6:00] and
[75°F (24°C)] are
selected.
Pressing
selects ON/OFF timer.
Pressing
deletes timer setting.
Pressing
adjusts the time.
Pressing
adjusts the tem-
perature.
* Hold down the button to change the time quickly.
* The temperature can be set between 61°F and 88°F (16°C and 31°C) at weekly timer.
*
blinks.
Pressing selects the day of
the week to be set.
Pressing selects
the setting number.
E.g. : [Mon Tue ... Sun]
and [1] are selected.
* All days can be selected.
1. How to set the weekly timer
Press and buttons to continue setting the timer for other days and/or numbers.
OBH736
17
NOTE:
• Press
button to transmit the setting information of weekly timer to the indoor unit. Point the remote controller toward the
indoor unit for 3 seconds.
• When setting the timer for more than one day of the week or one number,
button does not have to be pressed per each
setting. Press
button once after all the settings are complete. All the weekly timer settings will be saved.
• Press
button to enter the weekly timer setting mode, and press and hold button for 5 seconds to erase all weekly
timer settings. Point the remote controller toward the indoor unit.
(4) Press
button to complete and transmit the weekly timer setting.
* which was blink-
ing goes out, and the
current time will be
displayed.
2. Checking weekly timer setting2. Checking weekly timer setting
(1) Press button to enter the weekly timer setting mode.
*
blinks.
(2) Press
or buttons to view the setting of the particular day or number.
(3) Press
button to exit the weekly timer setting.
NOTE:
When all days of the week are selected to view the settings and a different setting is included among them,
will be
displayed.
(5) Press
button to turn the weekly timer ON. ( lights.)
•When the weekly timer is ON, the day of the week whose timer setting is complete, will light.
Press
button again to turn the weekly timer OFF. ( goes out.)
NOTE:
The saved settings will not be cleared when the weekly timer is turned OFF.
OBH736
18
8-9. SMART SET ( ) OPERATION
1. How to set SMART SET operation
(1) Press STOP/OPERATE (OFF/ON) button.
(2) Select COOL, HEAT or ECONO COOL mode.
(3) Press SMART SET button.
(4) Set the temperature, fan speed, and airfl ow direction for SMART SET operation.
NOTE:
• Select the appropriate temperature, fan speed, and airfl ow direction according to your room.
• SMART SET operation cannot be selected during DRY or AUTO mode operation.
• The setting range of HEAT mode SMART SET operation is 50°F (10°C) and 61 - 88°F (16 - 31°C).
• 2 groups of setting can be saved. (One for COOL/ECONO COOL, one for HEAT)
• SMART SET operation and the weekly timer operation cannot be used together.
2. How to cancel operation
• Press SMART SET button again.
• SMART SET operation can also be cancelled by pressing OPERATION SELECT button to change the operation mode.
The same setting is select from the next time by simply pressing SMART SET button.
• SMART SET operation cannot be set on the weekly timer.
8-10. EMERGENCY/TEST OPERATION
In the case of test run operation or emergency operation, use
EMERGENCY OPERATION switch on the right side of the indoor unit.
Emergency operation is available when the remote controller is missing
or has failed, or when the batteries in the remote controller are running
down. The unit will start and OPERATION INDICATOR lamp will light up.
The first 30 minutes of operation is the test run operation. This opera-
tion is for servicing. The indoor fan runs at High speed and the tem-
perature control does not work.
After 30 minutes of test run operation, the system shifts to
EMERGENCY COOL/HEAT MODE with a set temperature of 75°F (24°C).
The fan speed shifts to Medium.
The coil frost prevention works even in the test run or the emergency
operation.
In the test run or emergency operation, the horizontal vane operates in
VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION
switch is pressed once or twice or the unit receives any signal from the
remote controller. In the latter case, normal operation will start.
NOTE: Do not press EMERGENCY OPERATION switch during normal
operation.
Operation mode COOL/HEAT
Set temperature 75°F (24°C)
Fan speed Med.
Horizontal vane Auto
The operation mode is indicated by the Operation
Indicator lamp as follows.
Operation Indicator lamp
EMERGENCY COOL
↓
EMERGENCY HEAT
↓
STOP
Lighted
Not lighted
8-11. 3-MINUTE TIME DELAY OPERATION
When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect
compressor from overload.
8-12. Changing temperature indication (°F/°C)
• The preset unit is °F.
• °F → °C: Press RESET button while the temperature
buttons are pressed.
• °C → °F: Press RESET button or remove the batteries .
Press RESET button gently using
a thin instrument.
Emergency
operation switch
(E.O. SW)
OBH736
19
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 miswiring.
2. Take care of the following during servicing
1) Before servicing the air conditioner, be sure to turn OFF the main 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 P.C. board.
3) When removing the 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 connector housing. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) 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 OPERATION INDICATOR lamp is flashing ON and OFF before starting serv-
ice work.
2) Before servicing, check that the connector and terminal are connected properly.
3) When the electronic control P.C. board seems 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.
Lead wiring
Connector housing
<Incorrect>
<Correct>
TROUBLESHOOTING
9
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.
3. Do not use the leaking batteries.
Press RESET button with a thin instrument, and
then use the remote controller.
Remove the front lid and insert batteries.
Then reattach the front lid.
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
RESET button
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
OBH736
20
9-2. FAILURE MODE RECALL FUNCTION
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 (9-4.) disappears, the memorized failure details can
be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Does the left lamp of the OPERATION INDICA-
TOR lamp on the indoor unit blink at the interval of
0.5 seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing as the
blinking of the left lamp of OPERATION
INDICATOR lamp. 2
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnor-
malities that cannot be recalled with this way.
Check if outdoor unit is abnormal according to the detailed outdoor unit
failure mode recall function.
No
Yes
Judgment of indoor/outdoor abnormality
Before blinking, does the left lamp of
OPERATION INDICATOR lamp stay ON for 3
seconds?
When it stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
indoor unit failure mode table. (Refer to 9-2.2)
Make sure to check at least 2 consecutive blinking cycles.
2
Releasing the failure mode recall function
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.
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring
to the outdoor unit failure mode table. (Refer to outdoor unit service
manual.)
Make sure to check at least 2 consecutive blinking cycles.
3
Repair the failure parts.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall
function" mentioned above.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function"
mentioned above.
Yes
(Blinks)
No
(OFF)
NOTE: 1. Make sure to release the failure mode recall function after it is 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.
2. Blinking pattern when the indoor unit is abnormal:
3.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
The cause of abnormality cannot be found because the abnormality does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
<Preparation of the remote controller>
While pressing both OPERATION SELECT button and
TEMP
button
on the remote
controller at the same time, press RESET button.
First, release RESET button.
Hold down the other two buttons for another 3 seconds. Make sure that the indicators
on the LCD screen shown in the right fi gure are all displayed. Then release the but-
tons.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is
displayed) with the remote controller headed towards the indoor unit.
1
Operational procedure
1 Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.
NOTE: It takes up to 1 minute to indicate the outdoor unit abnormality.
Even if the OPERATION INDICATOR lamp is not lighting, keep
checking at least 1 minute or longer.
OBH736
21
2. Indoor unit failure mode table
The left lamp of
the OPERATION
INDICATOR lamp
Abnormal point
(Failure mode)
Condition Remedy
Not lighted Normal — —
1-time fl ash every
0.5-second
Room temperature
thermistor
The room temperature thermistor short or
open circuit is detected every 8 seconds dur-
ing operation.
Refer to the characteristics of the room temperature
thermistor (9-7.).
2-time fl ash
2.5-second OFF
Indoor coil
thermistor
The indoor coil thermistor short or open circuit
is detected every 8 seconds during operation.
Refer to the characteristics of the main indoor coil ther-
mistor, the sub indoor coil thermistor (9-7.).
3-time fl ash
2.5-second OFF
Serial signal
The serial signal from outdoor unit is not re-
ceived for a maximum of 6 minutes.
Refer to 9-6.
"How to check miswiring and serial
signal error".
11-time fl ash
2.5-second OFF
Indoor fan motor
The rotational frequency feedback signal is
not emitted for 12 seconds after the indoor fan
motor is operated.
Refer to 9-6.
"Check of indoor fan motor".
12-time fl ash
2.5-second OFF
Indoor control
system
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
Replace the indoor electronic control P.C. board.
NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (9-4.).
OBH736
22
9-3. INSTRUCTION OF TROUBLESHOOTING
Indoor unit oper-
ates.
Outdoor unit
does not operate.
If blinking of OPERATION INDI-
CATOR lamp cannot be checked,
it can be checked with failure
mode recall function.
Indoor unit operates.
Outdoor unit does
not operate normally.
Indoor unit does
not receive the
signal from re-
mote controller.
LEFT lamp of the OPERA-
TION INDICATOR lamp is
fl ashing ON and OFF.
Outdoor unit
operates only
in Test Run
operation.
Outdoor unit
does not
operate even
in Test Run
operation.
Unit does not
operate nor-
mal operation
in COOL or
HEAT mode.
Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.
Indoor unit does
not operate, when
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to 9-7.
"Test point
diagram and
voltage".
Refer to "How
to check
inverter/com-
pressor".
Refer to
"Check of R.V.
coil".
Refer to 9-6.
"Check of remote
controller and
indoor electronic
control P.C. board".
1. Check indoor/out-
door connecting wire.
(Check if the power is
supplied to the indoor
unit.)
2. Refer to 9-6. "Check
of indoor P.C. board
and indoor fan motor".
Left lamp
Flash on and
off at 0.5-sec-
ond intervals
Cause:
Indoor/Outdoor
unit
• Miswiring or
trouble of
serial signal
Left lamp
2-time fl ash
Cause:
Indoor unit
• Trouble
of room
temperature
/ indoor coil
thermistor
Left
lamp
3-time fl ash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Left lamp
4-time fl ash
Cause:
Indoor unit
• Trouble
of indoor
unit control
system
Left
lamp
5-time fl ash
Cause:
Outdoor unit
• Outdoor
power sys-
tem abnor-
mality
Left lamp
6-time fl ash
Cause:
Outdoor unit
• Trouble of
thermistor in
outdoor unit
Left lamp
7-time fl ash
Cause:
Outdoor unit
• Trouble of
outdoor con-
trol system
Left lamp
14-time fl ash
or more
Cause:
Outdoor unit
• Other ab-
normality
Start
Refer to 9-6.
"How to
check mis-
wiring and
serial signal
error".
Check room
temperature
thermistor
and indoor
coil thermis-
tor. Refer to
9-7. "Test
point diagram
and voltage".
Refer to 9-6.
"Check of
indoor fan
motor".
Replace the
indoor elec-
tronic control
P.C. board.
Refer to
"How to
check
inverter/com-
pressor".
Refer to
"Check of
outdoor ther-
mistors".
Replace the
inverter P.C.
board or
the outdoor
electronic
control P.C.
board.
Check "Flow
chart of the
detailed
outdoor unit
failure mode
recall func-
tion."
"Test Run operation" means the
operation within 30 minutes af-
ter EMERGENCY OPERATION
switch is pressed.
Refer to outdoor unit service manual.
OBH736
23
9-4. TROUBLESHOOTING CHECK TABLE
Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the
power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp flashes.
OPERATION INDICATOR
Lighted
Blinking
Not lighted
No.
Abnormal
point
Operation indicator lamp Symptom Condition Remedy
1
Miswiring
or serial
signal
Left lamp fl ashes.
0.5-second ON
0.5-second OFF
Indoor unit and
outdoor unit do
not operate.
The serial signal from the outdoor unit is not
received for 6 minutes.
•
Refer to 9-6.
"How to check
miswiring and serial signal er-
ror".
2
Indoor coil
thermistor
Left lamp fl ashes.
2-time fl ash
2.5-second OFF
The indoor coil or the room temperature ther-
mistor is short or open circuit.
•
Refer to the characteristics of
indoor coil thermistor, and the
room temperature thermistor
(9-7.).
Room tem-
perature
thermistor
3
Indoor fan
motor
Left lamp fl ashes.
3-time fl ash
2.5-second OFF
The rotational frequency feedback signal is
not emitted during the indoor fan operation.
•
Refer to 9-6.
"Check of in-
door fan motor".
4
Indoor con-
trol system
Left lamp fl ashes.
4-time fl ash
2.5-second OFF
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
•
Replace the indoor electronic
control P.C. board.
5
Outdoor
power sys-
tem
Left lamp fl ashes.
5-time fl ash
2.5-second OFF
It consecutively occurs 3 times that the com-
pressor stops for overcurrent protection or
start-up failure protection within 1 minute after
start-up.
•
Refer to "How to check of in-
verter/compressor".
Refer to outdoor unit service
manual
•
Check the stop valve.
6
Outdoor
thermistors
Left lamp fl ashes.
6-time fl ash
2.5-second OFF
The outdoor thermistors short or open circuit
during the compressor operation.
•
Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
7
Outdoor
control sys-
tem
Left lamp fl ashes.
7-time fl ash
2.5-second OFF
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the out-
door electronic control P.C. board.
•
Replace the inverter P.C. board
or the outdoor electronic control
P.C. board.
Refer to outdoor unit service
manual.
8
Other ab-
normality
Left lamp fl ashes.
14-time fl ash or more
2.5-second OFF
An abnormality other than above mentioned
is detected.
•
Check the stop valve.
•
Check the 4-way valve.
•
Check the abnormality in detail
using the failure mode recall
function for outdoor unit.
9
Outdoor
control sys-
tem
Left lamp lights up.
Outdoor unit
does not oper-
ate
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the out-
door 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.
• The following indicator applies regardless of shape of the indication.
OBH736
24
OPERATION INDICATOR
No.
Abnormal
point
Operation indicator lamp Symptom Condition Remedy
1
MXZ type
Operation
mode
setting
Left lamp lights and lower lamp fl ashes.
2.5-second OFF
Outdoor unit
operates but
indoor unit does
not operate.
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 fi rst has
the priority.
•
Unify the operation mode.
Refer to outdoor unit service
manual.
9-5. TROUBLE CRITERION OF MAIN PARTS
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Part name Check method and criterion Figure
Room temperature
thermistor (RT11)
Indoor coil thermistor
(RT12, RT13)
Measure the resistance with a tester.
Refer to 9-7. "Test point diagram and voltage", "Indoor electronic control P.C.
board", for the chart of thermistor.
Indoor fan motor (MF)
Check 9-6. "Check of indoor fan motor".
Vane motor (MV)
Measure the resistance between the terminals with a tester.
(Temperature: 50 - 86°F (10 - 30°C))
Color of the lead wire Normal
RED - BLK 232 - 268 Ω
BLK
BLK
RED
BLK
BLK
ROTOR
OBH736
25
A Check of indoor fan motor
9-6. TROUBLESHOOTING FLOW
The indoor fan motor error has occurred, and the indoor fan does not operate.
Turn OFF the power supply.
Is there any foreign matter that interferes
the rotation of the line fl ow fan?
Yes
No
Remove the foreign matter and
adjust the line fl ow fan.
Pay enough attention to the high voltage on the fan motor connector CN211.
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 EMER-
GENCY OPERATION switch is pressed.
If more than 12 seconds passes, turn OFF the power supply and turn it
ON again, then measure the voltage.
<Indoor power P.C. board>
1. Measure the voltage between CN211
(+) and (–).
2. Measure the voltage between CN211
(+) and (–).
<Indoor electronic control P.C. board>
3. Measure the voltage between CN102
(+) and JPG (GND)(–).
If more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage measured at 2. above goes 0 VDC although the
indoor P.C. board is normal.
Does the voltage between CN211
(+) and
(–) on the power P.C. board
rise to the range of 3 to 6 VDC within
12 seconds after EMERGENCY
OPERATION switch is pressed?
Replace the indoor fan motor.
Yes
No
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3 times, and then stops.
Measure the voltage between CN211
(+) and (–) while the fan motor is
rotating.
Replace the indoor power
P.C. board.
Is it unchanged holding
0 or 15 VDC?
No
(Changed)
Yes
(Unchanged)
Measure the voltage CN102 (+)
and JPG (GND)(–) on the indoor
electronic control P.C board when
the fan motor is rotating.
Replace the indoor fan motor.
Is there 294/325 VDC
between CN211
(+)
and
(–) ?
Yes
Does the voltage between CN102
(+) and JPG (GND)(–) on the indoor
electronic control P.C. board fall to
2 V or less within 12 seconds after
EMERGENCY OPERATION switch is
pressed?
Replace the indoor electronic
control P.C. board.
No
Yes
Replace the indoor power P.C.
board.
Is it unchanged holding
0 or 5 VDC?
No
(Changed)
Yes
(Unchanged)
Replace the indoor
electronic control P.C.
board.
No
OBH736
26
B Check of remote controller and indoor electronic control P.C. board
Check if the remote controller is exclusive for this air conditioner.
Does the unit operate with the
remote controller?
OK
Yes
No
(Not clear)
Replace the batteries. (Refer to 9-1.4.)
Press STOP/OPERATE (OFF/ON)
button on the remote controller.
Is LCD display on 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
No
Turn ON a radio to AM and press
STOP/OPERATE (OFF/ON) button
on the remote controller.
1
Is noise heard from radio?
Yes
No
Replace the remote controller.
Are there any fl uorescent lights
of inverter or rapid-start type
within the range of 3.28 ft.?
2
Yes
No
• Reinstall the unit away from lights.
• Attach a fi lter on receiving part.
Assign a number of remote controller.
(Refer to 7-2.)
Check if the unit operates with the
remote controller.
Does the unit operate with
the remote controller ?
Yes
No
OK
Replace the indoor electronic
control P.C. board (including the
receiver).
1 Look at the image of the signal transmitting section of
the remote controller through the monitor of a digital
camera or a camera phone. It is normal if the LED of
the signal transmitting section lights up when the STOP/
OPERATE (OFF/ON) button on the remote control-
ler is pressed. However, it may be diffi cult to see the
illuminated LED of the signal transmitting section with a
smartphone camera.
2 If the inverter fl uorescent light is turned on when the
room is cool, the unit may have diffi culty receiving the
signal from the remote controller or may not be able to
operate with it; if the inverter fl uorescent light is turned
on when the room is warm, the unit may be able to
operate with the remote controller.
OBH736
27
C Check of indoor P.C. board and indoor fan motor
Turn OFF the power supply.
Remove indoor fan motor connector CN211
from indoor power P.C. board 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 OPERATION INDICATOR lamp light
up by pressing EMERGENCY OPERATION
switch?
Yes
No
Measure the resistance of indoor fan
motor.
Refer to 9-5.
Short circuit:
Replace the indoor fan motor.
Turn OFF the power supply.
Check both “parts side” and “pattern
side” of the indoor power P.C. board
visually.
Replace the varistor (NR11)
and fuse (F11). 3
Are the varistor (NR11)
burnt and the fuse (F11)
blown?
No
No
Yes
Yes
Be sure to check both the fuse
and the varistor in any case.
Is the fuse (F11) blown
only?
Measure the resistance between
CN211
(+) and (-) of indoor fan
motor connector.
1, 2
Yes
Is the resistance 1MΩ or more?
Replace the fuse (F11) and the
indoor fan motor.
3No
Replace the fuse (F11).
3
Measure the resistance of
resistor (R111) on the indoor
power P.C. board.
No
No
Replace the indoor
power P.C. board and
the indoor fan motor.
Replace the indoor electronic control P.C. board.
Measure the resistance of the vane
motor coil.
Refer to 9-5.
Short circuit:
Replace the vane motor and the indoor
electronic control P.C. board.
1. The fan motor connector's lead wire is red,
whereas is black.
2. Connect "+" of the tester to fan motor connector's
lead wire, and “-” to lead wire, otherwise the
resistance cannot be measured properly.
3. Please replace the fuse after removing the indoor
power P.C. board from the electrical box.
Is there approximately 5 VDC between
5 V (+) and JPG (GND) (-) of the
indoor electronic control P.C. board?
Is there approximately 12 VDC
between 12 V (+) and JPG (GND) (-)
of the indoor electronic control P.C.
board?
Is connector CN102 on the
indoor electronic control P.C.
board or lead wires discon-
nected?
Yes
Replace the indoor fan motor.
Yes
Connect the connector or repair discon-
nection.
No
Yes
Is the resistance of
resistor (R111) approximately
3.9 Ω ?
Varistor
(NR11)
CN10A
Indoor electronic
control P.C. board
GND(JPG)
Fuse (F11)
R111
CN211
Indoor power
P.C. board
OBH736
28
D How to check miswiring and serial signal error
NOTE: Refer to the outdoor unit service manual.
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
A
Is serial signal
error indicated 6
minutes later?
B
Yes
• Reinstall
either the unit
or the light
away from
each other.
• Attach a fi lter
on remote
control receiv-
ing section
of the indoor
unit.
No
Turn OFF the power supply.
Is there rated voltage in the power supply?
Yes
No
Turn ON the power supply.
Check the power supply.
Is there rated voltage between the outdoor terminal block S1 and S2?
No
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICATOR
lamp light up? <Confi rmation of the power to
the indoor unit>
Yes
No
Is serial signal error indicated 6 minutes later?
Yes
No
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connect-
ing wire?
Yes
Correct them.
No
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3.
1
B
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confi rm the wiring is correct before the opera-
tion starts.
Turn ON the power supply.
Does the LED on the inverter P.C. board or the outdoor electronic control P.C.
board repeat "3.6-second-OFF and 0.8-second-ON quick blinking"?
3
Yes
No
(Lighted
or not
lighted)
Replace the inverter P.C. board or the
outdoor electronic control P.C. board.
2
2. Be careful of the residual voltage of
smoothing capacitor.
Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Confi rmation of serial signal>
Yes
Check the wiring
If there are any errors of the indoor/outdoor connecting wire:
such as the damage of the wire, intermediate connection,
and/or poor contact to the terminal block, replace the indoor/
outdoor connecting wire.
No
Is there 2 VDC or less between CN102 (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?
No
Yes
Yes
3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board is normal, LED blinks 6 times after 3
minutes. (Except for outdoor unit of multi system type)
Is there 2 VDC or less between
CN102 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
Is there 2 VDC or less between
CN102 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
Replace the indoor elec-
tronic control P.C. board.
No Yes No
Yes
Is the bus-bar voltage of the inverter P.C. board or the outdoor electronic control P.C. board
normal? (Refer to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.)
No
Yes
Check of power supply.
(Refer to the outdoor
service manual.)
Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Turn ON the power supply.
Yes
No
Replace the indoor power
P.C. board.
Is there rated voltage between the indoor terminal block S1 and S2?
<Confi rmation of power voltage>
OBH736
29
E Electromagnetic noise enters into TV sets or radios
Yes
Is the unit grounded?
No
Ground the unit.
Yes
Is the distance between the antennas
and the indoor unit within 9.91 ft. (3m),
or is the distance between the antennas
and the outdoor unit within 9.91 ft. (3m)?
No
Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.
Is the distance between the TV sets or ra-
dios and the indoor unit within 3.28 ft.
(1m)
,
or is the distance between the TV sets or
radios and the outdoor unit within
9.91 ft.
(3m)
?
Yes
Extend the distance between the TV sets and/or
radios and the indoor unit, or the TV sets or
radios and the outdoor unit.
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the anten-
na wiring?
Yes
No
No
Replace or repair the antenna.
Replace or repair the coaxial cable.
Is the indoor/outdoor connecting wire
of the air conditioner and the wiring of
the antennas close?
Yes
Extend the distance between the indoor/outdoor
connecting wire of the air conditioner and the wir-
ing of the antennas.
No
Even if all of the above conditions are fulfi lled, the electromagnetic noise may enter, depending on the electric fi eld strength
or the installation condition (combination of specifi c conditions such as antennas or wiring).
Check the following before asking for service.
1. Devices affected by the electromagnetic noise
TV sets, radios (FM/AM broadcast, shortwave)
2. Channel, frequency, broadcast station affected by the electromagnetic noise
3. Channel, frequency, broadcast station unaffected by the electromagnetic noise
4. Layout of:
indoor/outdoor unit of the air conditioner, indoor/outdoor wiring, ground wire, antennas, wiring from antennas, receiver
5. Electric fi eld intensity of the broadcast station affected by the electromagnetic noise
6. Presence or absence of amplifi er such as booster
7. Operation condition of air conditioner when the electromagnetic noise enters in
1) Turn OFF the power supply once, and then turn ON the power supply. In this situation, check for the electromagnetic
noise.
2) Within 3 minutes after turning ON the power supply, press STOP/OPERATE (OFF/ON) button on the remote control-
ler for power ON, and check for the electromagnetic noise.
3) After a short time (3 minutes later after turning ON), the outdoor unit starts running. During operation, check for the
electromagnetic noise.
4) Press STOP/OPERATE (OFF/ON) button on the remote controller for power OFF, when the outdoor unit stops but the
indoor/outdoor communication still runs on. In this situation, check for the electromagnetic noise.
OBH736
30
Indoor electronic
control P.C. board
Indoor power P.C. board
Fuse (F11) Varistor (NR11) Indoor fan motor
(CN211)
325 VDC
(–) GND (high-
voltage DC)
15 VDC
(+)3-6 VDC
(+)0 or 15 VDC
Connector to terminal
block (CN201)
Connector to indoor
electronic control P.C.
board (CN202)
Receiver board
Display board
Switch board
Resistor (R111)
5 VDC
12 VDC
GND
Timer short mode
point JPG JPS (Refer
to 8-1.)
To disable "Auto restart function",
cut the Jumper wire to JR77.
(Refer to 8-4.)
Emergency operation
switch (E.O.SW) (SW1)
Connector to power
P.C. board (CN102)
Room temperature ther-
mistor RT11 (CN111)
Vane motor
(CN151)
Indoor coil ther-
mistor RT12,
RT13 (CN112)
9-7. TEST POINT DIAGRAM AND VOLTAGE
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Room temperature thermistor (RT11)
Indoor coil thermistor (RT12, RT13)
Temperature (°F)
Resistance (kΩ)
32
50 68 86 104 122 140
OBH736
31
(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector has the
locking mechanism.
Slide the sleeve.
Pull the terminal while
pushing the locking
lever.
Hold the sleeve, and
pull out the terminal
slowly.
Connector
Sleeve
Locking lever
<"Terminal with locking mechanism" Detaching points>
The terminal which has the locking mechanism can be detached as shown below.
There are two types (Refer to (1) and (2)) of the terminal with locking mechanism.
The terminal without locking mechanism can be detached by pulling it out.
Check the shape of the terminal before detaching.
DISASSEMBLY INSTRUCTIONS
10
10-1.
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
NOTE: Turn OFF power supply before disassembly.
OPERATING PROCEDURE PHOTOS
1. Removing the panel
(1) Remove the horizontal vanes.
(2) Remove the screw caps of the panel. Remove the
screws of the panel.
(3) Unhook the lower part (
) of the panel.
(4) First, hold the lower part of the right end of the panel,
and hold the lower part of the left end of the panel.
(5) Pull the panel slightly toward you, and then remove
the panel by pushing it upward.
Photo 1
Photo: MSZ-EF•NAB
Screws of
the panel
Front panel Horizontal vanes
A
OBH736
32
OPERATING PROCEDURE PHOTOS
2. Remove the indoor electrical box
(1) Remove the panel (Refer to 1.) and the corner box
right.
(2) Remove the screw of the V.A. clamp.
Remove the V.A. clamp and the indoor/outdoor
connecting wire.
(3) Remove the ground wire connected to the indoor heat
exchanger from the electrical box.
(4) Remove the screw of the electrical cover and remove
the electrical cover.
(5) Disconnect following connectors:
<Indoor electronic control P.C. board>
CN151 (Vane motor)
<Indoor power P.C. board>
CN211 (Indoor fan motor)
(6) Remove the screw fixing the electrical box, then
the upper catch of the electrical box, and
pull out the electrical box.
Photo 2
Photo 3
Photo 4
3. Removing the indoor power P.C. board, the
switch board, the display board, the receiver
board and the indoor electronic control P.C.
board
(1) Remove the panel (Refer to 1.) and the corner box
right.
(2) Remove the screw of the V.A. clamp. Remove the V.A.
clamp and the indoor/outdoor connecting wire.
(3) Remove the screw of the conduit cover and the con-
duit cover. (Photo 3)
(4) Remove the screw of the conduit plate and the con-
duit plate. (Photo 4)
(5) Remove the screw fixing the electrical box.
(6) Remove the indoor electrical box (Refer to 2.).
(7) Remove the ground wire connected to the electrical
box from the indoor power P.C. board.
(8) Disconnect the following connectors:
<Indoor electronic power P.C. board>
CN201 (Terminal block)
CN202 (To the indoor electronic control P.C. board)
(9) Remove the indoor power P.C. board.
(10) Disconnect the following connectors:
<Indoor electronic control P.C. board>
CN111 (Room temperature thermistor)
CN112 (Indoor coil thermistor)
(11) Unhook the catches of the display P.C. board holder
from the nozzle and the electrical box (right side).
(12) Open the rear cover of the display P.C. board holder
and remove the switch board, the display board and
the receiver board.
Remove the indoor electronic control P.C. board.
Indoor power
P.C. board
Upper catch
Screw of
the V.A. clamp
Display P.C. board
holder
Screw of
the electrical cover
Electrical box
Ground wire
Screw of the
terminal block
Ground wire
Indoor electronic
control P.C. board
Catch of indoor electronic
control P.C. board holder
Catch of indoor electronic
control P.C. board holder
Screw of
the conduit plate
Screw of
the electrical box
Screw of
the conduit cover
OBH736
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OPERATING PROCEDURE PHOTOS
4. Removing the nozzle assembly
(1) Remove the panel (Refer to 1.) and the corner box
right.
(2) Remove the indoor/outdoor connecting wire (Refer to
2.).
(3) Remove the electrical cover (Refer to 2.).
(4) Disconnect the following connector:
<Indoor electronic control P.C. board>
CN151 (Vane motor)
(5) Remove the display P.C. board holder.
(6) Pull out the drain hose from the nozzle assembly and
remove the nozzle assembly.
(7) Remove the vane motors (Refer to 5.).
Photo 5
5. Removing the horizontal vane motor
(1) Remove the nozzle assembly (Refer to 4.).
(2) Remove the screws of the vane motor unit cover, and
pull out the vane motor unit
(3) Remove the screws of the vane motor unit.
(4) Disconnect the connector from the vane motor.
(5) Remove the vane motor from the vane motor unit.
Screws of
the vane motor unit
cover
Screws of
the vane motor
unit
OBH736
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OPERATING PROCEDURE PHOTOS
6. Removing the indoor fan motor, the indoor coil
thermistor and the line flow fan
(1) Remove the panel (Refer to 1.) and the corner box
right.
(2) Remove the indoor electronic control P.C. board
holder, the electrical box and the nozzle assembly.
(3) Remove the screws fixing the motor bed.
(4) Release the hooks of the water cut and remove the
water cut.
(5) Loosen the screw fixing the line flow fan.
(6) Remove the motor bed together with the indoor fan
motor and the motor band.
(7) Release the hooks of the motor band and remove the
motor band. Pull out the indoor fan motor.
(8) Remove the indoor coil thermistor from the heat
exchanger.
Install the indoor coil thermistor in its former position
when assembling it (Photo 6.).
(9) Remove the screws fixing the left side and the upper
right side of the heat exchanger (Photo 8, Photo 9).
(
10
)
Lift the heat exchanger, and pull out the line flow fan
to the lower-left.
When attaching the line flow fan, screw the line flow
fan so 4 mm gap is provided between the right end of
the line flow fan and the right wall of the air passage
of the box (Figure 1).
Photo 6
Photo 7
Photo 8
Screw of the line flow fan
Screws of
the left side of
the heat exchanger
Water cut
Screws of
the motor bed
Lead wire of
the indoor coil thermistor
Screw of
the upper right side of
the heat exchanger
Photo 9
Figure 1
4 mm
OBH736
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Fixing the indoor coil thermistor
There are 2 forms of parts for fixing the indoor coil thermistor.
NOTE:
Take care to avoid loss and accidental falling of the clip-shape part inside the unit.
Mount the clip-shape part on the marked position.
Do not pull the lead wire when removing the indoor coil thermistor.
Holder shapeClip shape
When fixing the indoor coil thermistor
to the clip-shape/holder-shape part, the
lead wire should point down.
1. Set the indoor coil
thermistor in the center
of the clip-shape part.
2. Check the (marked)
mounting position.
3. Mount the clip-
shape part.
Position and procedure for mounting the clip-shape part
About the
same length
OBH736
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
© Copyright 2015 MITSUBISHI ELECTRIC CORPORATION
Distributed in Oct. 2015. No. OBH736
Made in Japan
New publication, effective Oct. 2015
Specifications are subject to change without notice.
