Mitsubishi Electronics MFZ-KJ09NA- U1, MFZ-KJ12NA- U1, MFZ-KJ15NA- U1, MFZ-KJ18NA- U1 User Manual
INDOOR UNIT
INDOOR UNIT
SERVICE MANUAL
Models
U1
MFZ-KJ09NA
MFZ-KJ12NA
-
U1
-
Revision A:
• 3. SPECIFICATION and 4. OUTLINES AND
DIMENSIONS have been modified.
Please void OBH752.
No. OBH752
REVISED EDITION-A
MFZ-KJ15NA
MFZ-KJ18NA
U1
-
U1
-
Outdoor unit service manual
MUFZ-KJ•NAHZ Series (OBH753)
MXZ-C•NA, MXZ-C•NAHZ Series
(OBH702, OCH573)
CONTENTS
1. TECHNICAL CHANGES ··································· 3
2. PART NAMES AND FUNCTIONS ····················· 4
3. SPECIFICATION ················································ 5
4. OUTLINES AND DIMENSIONS ························ 7
5. WIRING DIAGRAM ············································ 8
6. REFRIGERANT SYSTEM DIAGRAM ··············· 9
7. SERVICE FUNCTIONS ··································· 10
8. MICROPROCESSOR CONTROL ··················· 12
9. TROUBLESHOOTING ····································· 21
10. DISASSEMBLY INSTRUCTIONS ···················· 36
PARTS CATALOG (OBB752)
NOTE:
• This service manual describes technical data of the indoor units.
• RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the RoHS Parts List.
Use the specifi ed refrigerant only
OBH752A
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.
Revision A:
• 3. SPECIFICATION and 4. OUTLINES AND DIMENSIONS have been modified.
2
1
OBH752A
TECHNICAL CHANGES
MFZ-KJ09NAMFZ-KJ12NAMFZ-KJ15NAMFZ-KJ18NA-
1. New model
U1
U1
U1
U1
3
2
OBH752A
PART NAMES AND FUNCTIONS
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Air outlet
0XOWLÀRZYDQH
$LUFOHDQLQJ¿OWHU
(Anti-allergy enzyme filter, option)
Front panel
$LU¿OWHU
1DQRSODWLQXP¿OWHU
Display and operation section (When the front panel is opened)
Horizontal vane
Vertical vane
Fan guard
Panel
ACCESSORIES
E.O
SW
Remote control receiving section
Operation indicator lamp
MFZ-KJ09NA MFZ-KJ12NA
MFZ-KJ15NA MFZ-KJ18NA
Drain hose 1
Remote controller holder 1
Fixing screw for 3.5 x 16 mm (Black) 2
Pipe cover 1
Band 2
Battery (AAA) for remote controller 2
Indoor unit mounting bracket 1
Fixing screw for 4 x 25 mm 5
Wood screw for the indoor unit fi xation 4
Washer of 4
Felt tape (Used for left or left-rear piping) 1
Wireless remote controller 1
Emergency operation
switch
4
3
OBH752A
1. Single connection
Indoor model MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Power supply V, phase, Hz 208/230, 1, 60
Max. fuse size (time delay)/ Disconnect switch
Airfl ow
Super High - High - Med. Low - Quiet
Sound level
Super High - High - Med. Low - Quiet
Cond. drain connection O.D. in. 5/8
Dimensions
Weight Ib. 33
External fi nish White
Control voltage (by built-in transformer) 12 - 24 VDC
NOTE: Test conditions are based on ARI 210/240.
2. Multi connection
Indoor model MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Power supply V, phase, Hz 208/230, 1, 60
Max. fuse size (time delay)/ Disconnect switch
Airfl ow
Super High - High - Med. Low - Quiet
Sound level
Super High - High - Med. Low - Quiet
Cond. drain connection O.D. in. 5/8
Dimensions
Weight Ib. 33
External fi nish White
Control voltage (by built-in transformer) 12 - 24 VDC
NOTE: Test conditions are based on ARI 210/240.
SPECIFICATION
A15 20
COOL Dry
HEAT Dry CFM 417 - 328 - 254 - 191 - 138
Cooling dB (A) 46 - 41 - 34 - 27 - 21
Heating dB (A) 46 - 40 - 34 - 27 - 21
W
D 8-15/32
H 23-5/8
COOL Dry
HEAT Dry CFM 343 - 219 - 180 - 159 - 138
Cooling dB (A) 38 - 34 - 30 - 25 - 21 43 - 40 - 36 - 31 - 28
Heating dB (A) 41 - 32 - 27 - 24 - 21 49 - 39 - 36 - 34 - 29
W
D 8-15/32
H 23-5/8
CFM
(Wet)
in.
A15 20
CFM
(Wet)
in.
417 - 360 - 272 - 198 - 138
(354 - 306 - 231 - 168 - 117)
275 - 251 - 208 173 - 138
(234 - 213 - 177 - 147 - 117)
431 - 392 - 311 - 254 - 198
(366 - 333 - 264 - 216 - 168)
470 - 399 - 328 - 268 - 212
47 - 43 - 38 - 33 - 28 50 - 45 - 39 - 33 - 28
49 - 45 - 40 - 35 - 29 49 - 45 - 40 - 35 - 29
29-17/32
374 - 328 - 282 - 237 - 198
(318 - 279 - 240 - 201 - 168)
470 - 325 - 290 - 254 - 212
29-17/32
491 - 420 - 328 - 254 - 198
(417 - 357 - 279 - 216 - 168)
5
3-1. OPERATING RANGE
OBH752A
(1) POWER SUPPLY
Rated voltage Guaranteed voltage (V)
Indoor unit
208/230 V
1 phase
60 Hz
(2) OPERATION
Mode Condition
Standard temperature 80 67 95 —
Cooling
Heating
Maximum temperature 90 73 115 —
Minimum temperature 67 57 14 —
Maximum humidity 78% —
Standard temperature 70 60 47 43
Maximum temperature 80 67 75 65
Minimum temperature 70 60 -13 -14
3-2. OUTLET AIR SPEED AND COVERAGE
1. Single connection
Model Mode Function
MFZ-KJ09NA
MFZ-KJ12NA
MFZ-KJ15NA
MFZ-KJ18NA
HEAT Dry 417 20.3 29.6
COOL
HEAT Dry 470 22.9 33.3
COOL
HEAT Dry 470 22.9 33.3
COOL
Dry 417 20.3 29.6
Wet 354 17.2 25.3
Dry 431 21.0 30.6
Wet 366 17.8 26.2
Dry 491 23.9 34.8
Wet 417 20.3 29.7
Airfl ow
(CFM)
Min. 187
DB WB DB WB
208 230 Max. 253
Intake air temperature (°F)
Indoor Outdoor
● The air coverage is the figure up to the
Air speed
(ft./s.)
Coverage
(ft.)
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.
2. Multi connection
Model Mode Function
MFZ-KJ09NA
MFZ-KJ12NA
MFZ-KJ15NA
MFZ-KJ18NA
Airfl ow
(CFM)
HEAT Dry 343 16.7 24.5
COOL
HEAT Dry 470 22.9 33.3
COOL
Dry 275 13.4 19.8
Wet 234 11.4 16.9
Dry 374 18.2 26.7
Wet 318 15.5 22.8
Air speed
(ft./s.)
Coverage
6
(ft.)
4
OBH752A
OUTLINES AND DIMENSIONS
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Unit: inch
7
5
OBH752A
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
WIRING DIAGRAM
8
6
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT12, RT14,
RT15
(main)
RT13 (sub)
Flared connection
Refrigerant flow in cooling
Refrigerant flow in heating
Refrigerant pipe 3/8 ( 9.52) (MFZ-KJ09/12)
1/2 ( 12.7) (MFZ-KJ15/18)
(with heat insulator)
Refrigerant pipe 1/4 ( 6.35)
(with heat insulator)
Distributor
OBH752A
REFRIGERANT SYSTEM DIAGRAM
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Unit: inch (mm)
9
7
OBH752A
SERVICE FUNCTIONS
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
7-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging the timer short mode point 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 minute.
•
After the breaker is turned on, the time for starting the compressor, which normally takes 3 minutes, can be reduced to 3
•
seconds. Restarting the compressor, which takes 3 minutes, 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. How to modify the electronic control P.C. board
Turn OFF the power supply before modification. To assign a number to each indoor unit , cut off “JR05” and “JR06” on the
electronic control P.C. board as shown in Table 1. (Refer to 9-7.)
Table 1
Indoor electronic
control P.C. Board
Fuse (F11)
Unit No. 1
Unit No. 2
Unit No. 3
Unit No. 4
JR05
No modification
Cut off JR05
No modification
Cut off JR05
JR06
No modification
No modification
Cut off JR06
Cut off JR06
VARISTOR (NR11)
R111
JR05
JR06
CN211
2. How to set the remote controller
(1) Hold down
(2) Press
Each press of
(3) Press
After the setting, turn ON the power supply and with the remote controller headed towards the indoor unit, press the
STOP/OPERATE (OFF/ON) button. If 1 or 2 beeps are heard from the indoor unit, the setting is completed correctly.
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.
button on the remote controller for 2 seconds to enter the pairing mode.
button again and assign a number to each remote controller.
button advances the number in the following order: 1 → 2 → 3 → 4.
button to complete the pairing setting.
CN151
10
7-3. AUTO RESTART FUNCTION
OBH752A
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.)
CN201 F11
L101
JR77
CN211
CN 111
C111
CN104
T111
CN105
CN123
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 cur-
rent by adding to the system that allows the units to start one by one.
11
8
OBH752A
MICROPROCESSOR CONTROL
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
WIRELESS REMOTE CONTROLLER
Signal transmitting section
Distance of signal :
About 20 ft. (6 m)
Beep(s) is (are) heard from
the indoor unit when the
signal is received.
OPERATION SELECT button
ECONO COOL button
Operation display section
SLEEP button
SMART SET button
FAN SPEED CONTROL button
POWERFUL button
VANE CONTROL button
TIME, TIMER set buttons
FORWARD button
BACKWARD button
TEMPERATURE buttons
STOP/OPERATE
(OFF/ON) button
Indication of
remote controller
model is on back
WEEKLY TIMER
set buttons
RESET button
CLOCK button
Lid
Slide the lid down
to open the remote
controller. Slide it down
further to get to the
weekly timer buttons.
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
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
The room temperature is
approaching the set temperature
About 4 °F (2°C) or more
away from set temperature
About 2 to 4 °F (1 to 2°C)
from set temperature
Lighted
Blinking
Not lighted
Standby mode (only during
multi system operation)
—
12
8-1. COOL ( ) OPERATION
OBH752A
(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
- 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 at the setting fan speed.
or button to select the desired temperature. The setting range is 61 - 88°F (16
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.)
However in AUTO setting, the fan speed changes.
8-3. FAN ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
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.
NOTE: Temperature cannot be set during FAN mode.
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
- 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 temperature 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 condensing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
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.
or button to select the desired temperature. The setting range is 61 - 88°F (16
13
8-5. AUTO CHANGE OVER ··· AUTO MODE OPERATION
OBH752A
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
If the room temperature thermistor RT11 reads more than set temperature, COOL mode is selected.
If the room temperature thermistor RT11 reads set temperature or less, HEAT mode is selected.
(2) Mode change
In case of the following conditions the operation mode is changed.
COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 4 °F (2 degrees C)
below the set temperature.
HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 4 °F (2 degrees C)
below the set temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE 1: Mode selection is performed when multi standby (refer to NOTE 2) is released and the unit starts operation
with ON-timer.
NOTE 2: If 2 or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO (
of standby.
NOTE 3: At the beginning of AUTO mode, the air flow direction and the fan speed are set to AUTO and the air outlet
selection is set to 2 FLOW.
), cannot change over the other operating mode (COOL ↔ HEAT) and becomes a state
8-6. AUTO VANE OPERATION
1. Horizontal vane (Horizontal vane/Multi-flow 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 VDC) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL (
) button.
(AUTO) (2) (3) (4)(1) (SWING)
(3) Positioning
The vane presses the vane stopper once to confirm the standard position and then moves to the set angle.
Confirming of standard position is performed in case of follows.
(a) The power supply turns on.
(b) The operation starts or finishes (including timer operation).
(c) The test run starts.
(d) The multi-standby starts or finishes.
(e) Every time the vane has swung more than the specified numbers of times.
(f) The horizontal vane automatically moves in certain intervals to determine its position, and then it returns to
set position.
(g) The vane operates for the dew prevention.
(4) Air outlet selection
The air outlet(s) can be selected by pressing to VANE CONTROL (
When 2 FLOW is selected, air blows from the top and the front of the unit. When 1 FLOW is selected, air blows only
from the top of the unit.
(2 FLOW) (1 FLOW)
) button.
14
The multi-flow vane is automatically set to the appropriate position.
OBH752A
In HEAT, the multi-flow vane automatically changes its position according to the indoor fan speed.
Even if 2 FLOW is selected, air will blow only from the top of the unit in the following conditions:
• During COOL/DRY: The room temperature is close to set temperature.
The air conditioner has operated for 0.5 to 1 hour.
• During HEAT: The air flow temperature is low. (During defrosting operation, start of operation, etc.)
NOTE:
Movement at the start of the 2 FLOW operation
• COOL/DRY, HEAT: It takes 0.5 to 1 minute to start the 2 FLOW operation.
• HEAT: When cold air blows out from the air outlet, the multi-flow vane may stop moving for up to 10 minutes to
make and blow out warm air.
(5) VANE AUTO (
In VANE AUTO mode, the microprocessor automatically determines the horizontal vane angle to make the optimum
room temperature distribution.
In COOL, DRY and FAN operation
2 FLOW: Vane angle is fixed to position 2.
) mode
In HEAT operation
2 FLOW: Vane angle is fixed to position 2.
1 FLOW: Vane angle is fixed to position 1. 1 FLOW: Vane angle is fixed to position 3.
(6) 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.
(7) Dew prevention
During COOL or DRY operation with the vane angle at Angle 3 or 4 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.
(8) SWING (
By selecting SWING mode with VANE CONTROL button, the horizontal vanes swing vertically.
The remote controller displays " ". SWING mode is cancelled when VANE CONTROL button is pressed once again.
(9) Cold air prevention in HEAT operation
The horizontal vane position is set to Upward.
(
10
) 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
horizontal 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, VANE CONTROL, POWERFUL button.
) mode
15
11
OBH752A
) POWERFUL ( ) operation
(
The air conditioner automatically adjusts the fan speed and the set temperature, and operates the POWERFUL
mode.
The POWERFUL mode is cancelled automatically 15 minutes after operation starts, or when POWERFUL button
is pressed once again within 15 minutes after operation starts. The operation mode returns to the mode prior to
POWERFUL operation. To cancel this operation manually, select a different mode or press one of the following buttons within 15 minutes after operation starts: STOP/OPERATE (OFF/ON), ECONO COOL, FAN SPEED CONTROL,
SLEEP or SMART SET button.
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 “0:00” 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 (
• Each time FORWARD button (
button (
• 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(
(b) Set the time of the timer using TIME SET buttons (
OFF timer setting
(a) Press OFF TIMER button (
(b) Set the time of the timer using TIME SET buttons (
) is pressed, the set time decreases by 1 minute.
and ) to set the current time.
) is pressed, the set time increases by 1 minute, and each time BACKWARD
) during operation.
) during operation.
Each time FORWARD button ( ) is pressed, the set time increases by 10 minutes: each time BACKWARD
ton (
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.
) is pressed, the set time decreases by 10 minutes.
).
).
and ).
and ).
but-
PROGRAM TIMER
• 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.
• “
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
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.
(Example 2) The current time is 11:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
16
8-8. WEEKLY TIMER OPERATION
OBH752A
• 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.
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)
81°F (27°C)
PM 5:30AM 6:00 AM 8:30 PM 10:00
PM 9:00PM 8:00
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 cannot be set to 50°F (10°C).
• The weekly timer operation and SMART SET operation cannot be used together.
1. How to set the weekly timer
* Make sure that the current time and day are set correctly.
(1) Press button to enter the weekly timer setting mode.
blinks.
*
(2) Press
and buttons to select setting day and number.
E.g. : [Mon Tue ... Sun]
and [1] are selected.
Pressing selects the day of
the week to be set.
Pressing selects
the setting number.
(3) Press , , and buttons to set ON/OFF, time, and temperature.
* All days can be selected.
E.g. : [ON], [AM 6:00] and
[75°F (24°C)] are
selected.
Pressing
selects ON/OFF timer.
Pressing
deletes timer setting.
* 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.
Pressing
adjusts the time.
Pressing
adjusts the temperature.
Press and buttons to continue setting the timer for other days and/or numbers.
17
(4) Press
OBH752A
NOTE:
• Press
indoor unit for 3 seconds.
button to complete and transmit the weekly timer setting.
button to transmit the setting information of weekly timer to the indoor unit. Point the remote controller toward the
* which was blink-
ing goes out, and the
current time will be
displayed.
• When setting the timer for more than one day of the week or one number,
setting. Press
• Press
timer settings. Point the remote controller toward the indoor unit.
(5) Press
Press
NOTE:
The saved settings will not be cleared when the weekly timer is turned OFF.
button to enter the weekly timer setting mode, and press and hold button for 5 seconds to erase all weekly
•When the weekly timer is ON, the day of the week whose timer setting is complete, will light.
button again to turn the weekly timer OFF. ( goes out.)
button once after all the settings are complete. All the weekly timer settings will be saved.
button to turn the weekly timer ON. ( lights.)
button does not have to be pressed per each
2. Checking weekly timer setting2. Checking weekly timer setting
(1) Press button to enter the weekly timer setting mode.
*
(2) Press
(3) Press
NOTE:
When all days of the week are selected to view the settings and a different setting is included among them,
displayed.
blinks.
or buttons to view the setting of the particular day or number.
button to exit the weekly timer setting.
8-9. SLEEP ( ) OPERATION
1. How to set SLEEP operation
(1) Press STOP/OPERATE (OFF/ON) button.
(2) Select COOL, DRY, HEAT or FAN mode.
(3) Press SLEEP (
) button.
will be
(4) PRESS TEMPERATURE buttons [
operation.
Fan speed: AUTO
Horizontal vane: Position set on the remote controller
Operation indicator lamp: Dimly lit
• Once the above procedure is completed, the settings will be saved.
• After the settings are saved, a single push of SLEEP (
same settings every time.
• Temperature for SLEEP operation cannot be set during DRY or FAN mode.
(Increase) and (Decrease) ] to set the temperature of SLEEP
) button during operation activates SLEEP operation with the
18
Set temperature for SLEEP operation.
OBH752A
For about 30 minutes after
SLEEP (
) button
is pressed, the set temperature remains as set for the operation running
when the SLEEP button is pressed. It will change to the set temperature for SLEEP operation in about 30 minutes.
Pressing
SLEEP (
) button
again returns the operation to the previous settings.
is
pressed.
Set
temperature for
the operation
before SLEEP
operation
For about 30
minutes
Set temperature for
SLEEP operation
is
pressed.
Set temperature for
the operation before
SLEEP operation
NOTE:
• ON/OFF timer is available during SLEEP operation.
• When a preset ON time for the weekly timer arrives during SLEEP operation, the weekly timer operation has priority. SLEEP
operation will be cancelled, and the operation set on the weekly timer will start.
2. How to cancel operation
• Press SLEEP (
) button again.
• The operation returns to the previous settings.
• SLEEP operation is also cancelled when the FAN button is pressed or the operation mode is changed.
NOTE: SLEEP operation and SMART SET operation cannot be set at same time.
8-10. 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:
• 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.
• SMART SET operation and SLEEP operation cannot be set at the same time.
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 selected from the next time by simply pressing SMART SET button.
19
8-11. EMERGENCY/TEST OPERATION
OBH752A
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 operation
is for servicing. The indoor fan runs at High speed and the temperature
control does not work. In COOL/HEAT MODE, the air outlet selection is
set to 2 FLOW during the test run operation. However, 2 FLOW operation in HEAT MODE is the same operation as the case that 2 FLOW
operation is selection by the remote controler.
After 30 minutes of test run operation, the system shifts to
EMERGENCY COOL/HEAT MODE with a set temperature of
The fan speed shifts to Medium.
(24°C).
In EMERGENCY COOL/HEAT MODE, the air outlet selection is set to
2 FLOW. 2 FLOW operation is the same operation as the case that 2
FLOW operation is selection by the remote controler.
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.
75°F
Operation mode COOL/HEAT
Set temperature 75°F (24°C)
Fan speed Medium
Horizontal vane Auto
Air outlet 2 FLOW
The operation mode is indicated by the Operation
Indicator lamp as following
Operation Indicator lamp
EMERGENCY COOL
↓
EMERGENCY HEAT
↓
STOP
Emergency
operation switch
(E.O. SW)
Lighted
Not lighted
NOTE: Do not press EMERGENCY OPERATION switch during normal
operation.
8-12. 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.
8-13. 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 while the TEMPERATURE buttons are pressed.
Press RESET button gently
using a thin instrument.
20
9
Lead wiring
Connector housing
<Incorrect>
<Correct>
OBH752A
TROUBLESHOOTING
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
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.
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
service 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.
Remove the front lid and insert batteries.
Then reattach the front lid.
Press RESET button with a thin instrument, and
then use the remote controller.
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.
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
RESET button
21
5. Description of multi system air conditioner
OBH752A
OUTDOOR UNIT: MXZ series
The multi system outdoor unit can be connected to 2 or more indoor units.
•
The units do not operate and the operation indicator lamp flashes as shown in the figure below when the total capacity of
the indoor units exceed the capacity of the outdoor unit. Do not connect the indoor units beyond the outdoor unit capacity.
• When operating the 2 or more indoor units connected to a multi system outdoor unit, set all the indoor units to the
same operation mode. If the COOL and the HEAT modes are selected for those indoor units, the indoor unit which has
started operation first has a priority. The other indoor units set to the different operation mode later do not start operation and the operation indicator lamp flashes as shown in the figure below.
OPERATION INDICATOR
Lighted
(Green)
Blinking
Not lighted
When the indoor units start operation while the defrosting of the outdoor unit is being performed, it takes a few minutes (up
•
to 10 minutes) to blow out warm air.
In the heating operation, even though the indoor unit is not running, the room may get warm or the sound of refrigerant
•
flowing may be heard. This is not a malfunction. They happen because the refrigerant is continuously flowing inside the
unit.
(Green)
22
9-2. FAILURE MODE RECALL FUNCTION
OBH752A
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though OPERATION INDICATOR lamp indication listed on the troubleshooting check table (9-4.) disappears, the
memorized failure details can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which does not recur.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Operational procedure
Setting up the failure mode recall function
The cause of abnormality cannot be found because the abnormality does not recur.
Turn ON the power supply.
<Preparation of the remote controller>
While pressing OPERATION SELECT (MODE) button and TEMP
remote controller at the same time, press RESET button.
First, release RESET button.
Hold down the other 2 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 buttons.
button on the
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. Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.
Does the left lamp of the OPERATION INDICATOR lamp on
the indoor unit blink at the interval of 0.5 seconds?
Blinks: Either indoor or outdoor unit is abnormal. Beep is emit-
ted at the same timing as the blinking of the left lamp of
the OPERATION INDICATOR lamp.
Judgment of indoor/outdoor abnormality
Releasing the failure mode recall function
Deleting the memorized abnormal condition
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.
Before blinking, does the left lamp of the 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 indoor unit service manual.)
Make sure to check at least 2 consecutive blinking cycles.
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.
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. 4
Release the failure mode recall function according to "Releasing the failure mode recall function"
mentioned above.
Yes
(Blinks)
No
Repair the failure parts.
2
2
1
No
(OFF)
Yes
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnormalities
that cannot be recalled with this way.
Check if the outdoor unit is abnormal according to the detailed outdoor unit
failure mode recall function. (Refer to 9-2.2)
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.
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to
the outdoor unit failure mode table.
Make sure to check at least 2 consecutive blinking cycles.
2. Blinking pattern when the indoor unit is abnormal:
2.5-second OFF
Blinking at 0.5second interval
2.5-second OFF
Blinking at 0.5second interval
ON
OFF
Repeated cycle Repeated cycle
Beeps
3.Blinking pattern when the outdoor unit is abnormal:
2.5-second OFF 3-second ON
Blinking at 0.5second interval
Beeps
Repeated cycle
2.5-second OFF 3-second ON
ON
OFF
No beep Beeps
Repeated cycle
No beep Beeps
Repeated cycle
3
4 The information regarding whether the connected
outdoor unit is a low-standby-power model or a nonlow-standby-power model will also be initialized.
(Default= compatible with a low-standby-power model)
Beeps
Blinking at 0.5second interval
Repeated cycle
23
2. Indoor unit failure mode table
OBH752A
NOTE: Blinking patterns of this mode differs from the ones of Troubleshooting check table (9-4.).
Left lamp of
OPERATION
INDICATOR lamp
Not lighted –Normal –
1-time flash
every 0.5-second
2-time flash
2.5-second OFF
3-time flash
2.5-second OFF
Right lamp of
OPERATION
INDICATOR lamp
Not lighted
Not lighted
Not lighted
Not lighted
Abnormal point
(Failure mode)
Room temperature
thermistor
Indoor coil thermistor
(Main 1, 2 and sub)
Serial signal error
Condition
The room temperature thermistor
short or open circuit is detected every 8
seconds during operation.
The indoor coil thermistor short or
open circuit is detected every 8 seconds
during operation.
The serial signal from the outdoor unit is
not received for a maximum of 6 minutes.
Refer to the characteristics of the room
temperature thermistor (9-7.).
Refer to the characteristic of the main
indoor coil thermistors 1 and 2 and the
sub indoor coil thermistor (9-7.).
Refer to 9-6. "How to check miswiring
and serial signal error".
Remedy
11-time flash
2.5-second OFF
12-time flash
2.5-second OFF
13-time flash
2.5-second OFF
Not lighted
Not lighted
Not lighted
Indoor fan motor
Indoor control system
Indoor coil thermistor
(Main 3)
The rotational frequency feedback
signal is not emitted during 12-second the
indoor fan operation.
It cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
The indoor coil thermistor short or
open circuit is detected every 8 seconds
during operation.
Refer to 9-6 "Check of indoor
fan motor.
Replace the indoor electronic control
P.C. board.
Refer to the characteristic of the main
indoor coil thermistor 3 (9-7.).
24
Start
Indoor unit
operates.
Outdoor unit
does not
operate.
Indoor unit does
not 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.
Outdoor unit
does not
operate
even in
Test Run
operation.
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/
compressor".
Refer to 9-6.
"Check of
remote controller,
display receiver
P.C. board and
indoor control
P.C. board".
1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to 9-6.
"Check of indoor
electronic control
P.C. board and indoor
fan motor".
Unit does
not 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
0LVZLULQJ
or trouble
of serial signal
Left
lamp
2-time flash
Cause:
Indoor unit
7URXEOHRI
room temp erature/
indoor coil
thermistor
Left
lamp
3-time flash
Cause:
Indoor unit
7URXEOHRI
indoor fan
motor
Left lamp
5-time flash
Cause:
Outdoor unit
2XWGRRU
power
system
abnormality
Left lamp
6-time flash
Cause:
Outdoor unit
7URXEOHRI
thermistor
in outdoor
unit
Left lamp
7-time flash
Cause:
Outdoor unit
7URXEOHRI
outdoor
control
system
Check room
temperature
thermistor
and indoor
coil thermistor.
Refer to 9-7.
"Test point
diagram and
voltage".
Refer to
"How to check
the 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
or more
Cause:
Outdoor unit
2WKHU
abnormality
Check
"Flow chart of
the detailed
outdoor unit
failure mode
recall function."
Refer to 9-6.
"How to
check
miswiring
and serial
signal error
(when
outdoor unit
does not
work)".
Refer to 9-6.
"Check of
indoor fan
motor".
Left lamp
4-time flash
Cause:
Indoor unit
7URXEOHRI
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
Refer to outdoor unit service manual.
Indoor unit operates.
Outdoor unit does
not operate normally.
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked with
failure mode recall function.
"Test Run operation" means the
operation within 30 minutes after
EMERGENCY OPERATION switch
is pressed.
9-3. INSTRUCTION OF TROUBLESHOOTING
OBH752A
25
9-4. TROUBLESHOOTING CHECK TABLE
OBH752A
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
Abnormal
No.
point
Left lamp flashes.
1
Miswiring
or serial
signal
0.5-second ON
0.5-second OFF
Lighted
Blinking
Not lighted
SymptomOperation indicator lamp Condition
Indoor unit
and outdoor
unit do not
operate.
The serial signal from the outdoor unit is not
received for a maximum of 6 minutes.
Remedy
5HIHUWR+RZWRFKHFN
miswiring and serial signal
HUURU
Indoor coil
thermistor
2
Room
temperature
thermistor
Indoor fan
3
motor
Indoor
4
control
system
Outdoor
5
power
system
Outdoor
6
thermistors
Outdoor
7
control
system
Other
8
abnormality
Left lamp flashes.
2-time flash
2.5-second OFF
Left lamp flashes.
3-time flash
2.5-second OFF
Left lamp flashes.
4-time flash
Left lamp flashes.
5-time flash
2.5-second OFF
Left lamp flashes.
6-time flash
2.5-second OFF
Left lamp flashes.
7-time flash
Left lamp flashes.
14-time flash or more
2.5-second OFF
2.5-second OFF
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.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
The indoor coil or the room temperature
thermistor is short or open circuit.
7KHURWDWLRQDOIUHTXHQF\IHHGEDFNVLJQDOLV
not emitted during the indoor fan operation.
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
It consecutively occurs 3 times that the
compressor stops for overcurrent protection or
start-up failure protection within 1 minute after
start-up.
The outdoor thermistors short or open circuit
during the compressor operation.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.
An abnormality other than above mentioned is
detected.
5HIHUWRWKHFKDUDFWHULVWLFVRI
indoor coil thermistor, and the
room temperature thermistor
on 9-7.
5HIHUWR&KHFNRI
LQGRRUIDQPRWRU
5HSODFHWKHLQGRRUHOHFWURQLF
control P.C. board.
5HIHUWR&KHFNRILQYHUWHU
FRPSUHVVRU
Refer to the outdoor unit
service manual.
&KHFNWKHVWRSYDOYH
5HIHUWR&KHFNRIRXWGRRU
WKHUPLVWRU
Refer to the outdoor unit
service manual.
5HSODFHWKHLQYHUWHU3&
board or the outdoor electronic
control P.C. board.
Refer to the outdoor unit
service manual.
&KHFNWKHVWRSYDOYH
&KHFNWKHZD\YDOYH
&KHFNWKHDEQRUPDOLW\LQ
detail using the failure mode
recall function.
Refer to the outdoor unit
service manual.
Outdoor
control
9
system
Left lamp lights up
Outdoor unit
does not
operate.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.
26
&KHFNWKHEOLQNLQJSDWWHUQRI
the LED on the inverter P.C.
board or the outdoor electronic
control P.C. board.
OPERATION INDICATOR
OBH752A
Lighted
Blinking
Not lighted
Abnormal
No.
1
point
MXZ type
Operation
mode
setting
Right lamp flash
2.5-second OFF
SymptomOperation indicator lamp Condition
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
first has the priority.
9-5. TROUBLE JUDGEMENT CRITERIA OF MAIN PARTS
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Part name FigureCheck method and criteria
Room temperature
thermistor (RT11)
Indoor coil thermistor
(RT12 (MAIN 1), RT13 (SUB)
RT14 (MAIN 2), RT15 (MAIN 3))
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.
Remedy
•
Select the same operation mode
for all the units.
Refer to the outdoor unit
service manual.
Indoor fan motor (MF)
Horizontal vane motor
(MV1) FRONT
Horizontal vane motor
(MV2) BACK
Multi-flow vane motor
(MV3)
Check 9-6. “Check of indoor fan motor” and “Check of indoor
electronic control P.C. board and indoor fan motor”.
Measure the resistance between the terminals with a tester.
(Part temperature: 50°F - 86°F (10°C - 30°C))
Color of the lead wire
%51RWKHURQH
Normal
Measure the resistance between the terminals with a tester.
(Part temperature: 50°F - 86°F (10°C - 30°C))
Color of the lead wire
%51RWKHURQH
Normal
Measure the resistance between the terminals with a tester.
(Part temperature: 50°F - 86°F (10°C - 30°C))
Color of the lead wire
%51RWKHURQH
Normal
RED
YLW
BRN
ROTOR
ORN
GRN
27
9-6. TROUBLESHOOTING FLOW
CN211
Fuse (F11)
VARISTOR (NR11)
Indoor electronic
control P.C. Board
CN151
R111
OBH752A
A Check of indoor fan motor
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
Remove the foreign matter and
adjust the line fl ow fan.
Is there 294/325 VDC
between CN211
and
(–) ?
(+)
No
Yes
No
Pay enough attention to the high voltage on the fan motor connector.
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, turn OFF the power supply and turn it
ON again, then measure the voltage.
<Indoor electronic control P.C. board>
1. Measure the voltage between CN211
2. Measure the voltage between CN211
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 indoor electronic
control P.C. board rise to the range
of 2 to 6 VDC within 12 seconds after
EMERGENCY OPERATION switch is
pressed?
No
Yes
(+) and (–).
(+) and (–).
Replace the indoor fan motor.
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" 3 times, and then stops.
Measure the voltage between CN211
(+) and (–) while the fan motor is
rotating.
Is it unchanged holding 0
or 15 VDC?
Yes
(Unchanged)
Replace the indoor fan motor.
No
(Changed)
Replace the indoor
electronic control P.C.
board.
28
B
OBH752A
Check of remote controller, display receiver P.C. board and indoor control P.C. board
Check if the remote controller is exclusive for this air conditioner.
Press STOP/OPERATE (OFF/ON)
button on the remote controller.
Is LCD display on the remote
controller visible?
Yes
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.
Does the unit operate with the
remote controller?
Yes
OK
No
(Not clear)
No
Replace the batteries. (Refer to 9-1.4.)
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
OK
No
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 controller 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.
Turn ON a radio to AM and press
STOP/OPERATE (OFF/ON) button
on the remote controller. 1
Is noise heard from radio?
Yes
Are there any fl uorescent lights of
inverter or rapid-start type within
the range of 3.28 ft. (1 m)?
2
No
Replace the remote controller.
No
• Reinstall the unit away from lights.
• Attach a fi lter on receiving part.
Yes
Measure the voltage between display receiver P.C. board connector CN301 (+) and (-)
when the remote controller button is pressed.
Yes
Is the voltage approximately 4 VDC - 5 VDC?
No
Replace the display receiver P.C. board.
Replace the indoor electronic
control P.C. board.
29
C
OBH752A
Check of indoor electronic control P.C. board and indoor fan motor
Turn OFF the power supply.
Remove indoor fan motor connector CN211
and vane motor connector CN151 from the
indoor electronic control P.C. board and turn
ON the power supply.
Does the unit operate with the remote
controller?
Does OPERATION INDICATOR lamp light
up by pressing EMERGENCY OPERATION
switch?
Turn OFF the power supply.
Check both “parts side” and “pattern
side” of the indoor electronic control
P.C. board visually.
No
Measure the resistance of indoor fan
motor.
Refer to 9-5.
Measure the resistance of the vane
motor coil.
Yes
Refer to 9-5.
Replace the varistor (NR11)
and fuse (F11).
Is the varistor (NR11)
burnt and the fuse (F11)
blown?
Be sure to check both the fuse
and the varistor in any case.
Is the fuse (F11) blown
only?
Measure the resistance between
(+) and (-) of indoor fan
CN211
motor connector.
3
Yes
Yes
1, 2
No
No
Short circuit:
Replace the indoor fan motor.
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
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
electronic control P.C. board from the electrical box.
is black.
VARISTOR (NR11)
R111
CN211
Measure the resistance of resistor (R111) on the indoor electronic
control P.C. board.
Indoor electronic
control P.C. Board
Fuse (F11)
CN151
Is the resistance 1MΩ or more?
Yes
Replace the fuse (F11).
Replace the indoor electronic control P.C. board.
3
Is the resistance of
resistor (R111) approximately 4 Ω?
Replace the fuse (F11) and the
indoor fan motor. 3
No
No
Yes
Replace the indoor
electronic control P.C.
board and the indoor fan
motor.
30
D
OBH752A
How to check miswiring and serial signal error
MUFZ Type
Turn OFF the power supply.
Is there rated voltage in the power supply?
Turn ON the power supply.
Is there rated voltage between the outdoor terminal block S1 and S2?
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICATOR
lamp light up? <Confi rmation of the power to
the indoor unit>
Is serial signal error indicated 6 minutes later?
Turn OFF the power supply.
Check once more if the indoor/outdoor
B
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
1
S3.
Turn ON the power supply.
Yes
Yes
Yes
Yes
A
No
No
No
1. Miswiring may damage indoor electronic control P.C.
3. Be sure to check this within 3 minutes after turning ON.
Check the power supply.
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connecting wire?
board during the operation.
Be sure to confi rm the wiring is correct before the opera-
tion starts.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board is normal, LED blinks 6 times after 3
minutes.
No
No
Check the wiring.
Correct them.
Yes
Is the bus-bar voltage of the inverter P.C. board normal?
(Refer to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.)
Does the LED on the inverter P.C. board repeat
"3.6-second-OFF and 0.8-second-ON quick blinking"?
Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there rated voltage between the indoor terminal block S1 and S2?
<Confi rmation of power voltage>
Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Confi rmation of serial signal>
Yes
A
• Reinstall
• Attach a fi lter
No
either the unit
or the light
away from
each other.
on remote
control receiving section
of the indoor
unit.
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn it ON again.
• Press EMERGENCY OPERATION
switch.
Is serial signal
error indicated 6
minutes later?
B
Yes
3
Yes
Yes
Yes
Is there 2 VDC or less between CN202 (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?
Yes
Is there 2 VDC or less between
CN202A
on the indoor electronic control P.C.
board?
Replace the indoor power
P.C. board.
No
(+) and JPG (GND)(-)
No Yes No
No
(Lighted
or not
lighted)
No
No
Replace the indoor electronic control P.C. board.
31
Check of power supply.
(Refer to the outdoor
No
service manual.)
Replace the inverter P.C. board . 2
2. Be careful of the residual voltage of
smoothing capacitor.
Check the wiring
If there are any error 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.
Is there 2 VDC or less between
CN202 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
Yes
MXZ Type
OBH752A
Turn OFF the power supply.
Is there rated voltage in the power supply?
Turn ON the power supply.
Is there rated voltage between outdoor terminal block S1 and S2?
Press EMERGENCY OPERATION switch once.
Does the left lamp of the OPERATION
INDICATOR lamp light up?
<Confi rmation of the power to the indoor unit>
Is serial signal error indicated 6 minutes later?
• Turn OFF inverter-controlled lighting equipment.
• Turn OFF the power supply and then turn it ON again.
• Press EMERGENCY OPERATION switch.
Is serial signal error indicated
6 minutes later?
Turn OFF the power supply.
Check once more if the indoor/outdoor connecting wire is not miswiring.
Remove the indoor/outdoor connecting wire from outdoor terminal block S3.
Bridge the outdoor terminal block S2 and S3.
Yes
Yes
Yes
Yes
Yes
1
No
No
Is there any miswiring,
poor contact, or wire
disconnection of the
No
indoor/outdoor connecting wire?
• Reinstall either the unit or the light away
from each other.
• Attach a fi lter on remote control receiving
No
section of the indoor unit.
Check the power supply.
No
No
Check the wiring.
Yes
Correct them.
(Refer to the next page.)
C
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.
32
LED indication
OBH752A
for communication status
Communication status is indicated
by the LED.
Unit status
Blinking: normal communication
Lighting: abnormal communication or
not connected
Pattern 1 and 2 is repeatedly displayed
alternately. Each pattern is displayed for
15 seconds.
NOTE: "Lighting" in the table below does not
indicate abnormal communication.
Outdoor control P.C. board
Pattern
1
2
3
LED 1 LED 3LED 2
Unit A
status
Unit C
status
Unit E
status
LED1 LED2
Blinking
LED3
Unit B
status
Unit D
status
Lighted
Not lighted
Blinking
C
Turn ON the power supply.
Does the LED on the outdoor control P.C.
board repeat "3.6-second-OFF
and 0.8-second-ON quick blinking"?
Yes
Turn OFF the power supply.
Remove the bridge between
outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20 VDC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>
Yes
Is there rated voltage between
indoor terminal block S1 and S2?
<Confirmation of power voltage>
Yes
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode
recall function after checking.
No
No
No
(Lighted
or
not lighted)
Replace the outdoor control P.C. board.
2
2 Be careful of the residual
voltage of smoothing capacitor.
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
No
Replace the
Yes
indoor/outdoor
connecting wire.
33
E Electromagnetic noise enters into TV sets or radios
OBH752A
Is the unit grounded?
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
Is the distance between the TV sets or radios and the indoor unit within 3.28 ft.
or is the distance between the TV sets or
radios and the outdoor unit within
9.91 ft.
(3m)
?
No
Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the antenna wiring?
No
Is the indoor/outdoor connecting wire
of the air conditioner and the wiring of
the antennas close?
No
(1m)
No
Yes
,
Yes
Yes
Yes
Ground the unit.
Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.
Extend the distance between the TV sets and/
or radios and the indoor unit, or the TV sets or
radios and the outdoor unit.
Replace or repair the antenna.
Replace or repair the coaxial cable.
Extend the distance between the indoor/outdoor
connecting wire of the air conditioner and the wiring of the antennas.
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 controller 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.
34
Indoor coil thermistor [RT12,RT14,RT15 (MAIN), RT13 (SUB)]
Room temperature thermistor (RT11)
Temperature (°F)
32 50 68 86 104 122 140
5HVLVWDQFHN
9-7. TEST POINT DIAGRAM AND VOLTAGE
OBH752A
MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
Indoor electronic control P.C. board
Varistor
(NR11)
Power supply (CN201)
input 208/230 VAC
Resistor
(R111 )
Connector cable (CN24)
Indoor fan motor
(CN211)
(+)0 or 15 VDC
(+)3-6 VDC
15 VDC
(–) GND (high-
voltage DC)
294/325 VDC
5 VDC
Timer short mode
point (2 points)
(Refer to 8-1.)
GND
Room temperature
thermistor RT11
(CN111)
FUSE (F11) T3.15AL250V
Serial signal
input (CN202)
JR05
JR06
To disable "Auto
restart function",
cut the Jumper
wire to JR77.
(Refer to 7-3.)
12 VDC
Connect to display
receiver P.C. board
(CN1J1)
Interface (CN105)
Modification
)
point for
individual
operation
(Refer to 7-2.)
Indoor coil thermistor (CN112)
Indoor coil thermistor RT15 (MAIN 3)
Indoor coil thermistor RT14 (MAIN 2)
Indoor coil thermistor RT12 (MAIN 1)
Indoor coil thermistor RT13 (SUB)
Display receiver P.C. board
Emergency operation
switch (E. O. SW) (SW301)
Connect to indoor electronic control P.C. board
(CN301)
Vane motor (CN151)
Horizontal
vane back
Horizontal
vane front
Multi-fl ow vane -
-
-
35
(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.
The terminal which has the locking mechanism can be detached as shown below.
There are 2 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.
<"Terminal with locking mechanism" Detaching points>
Connector
Sleeve
Locking lever
10
OBH752A
DISASSEMBLY INSTRUCTIONS
10-1. MFZ-KJ09NA MFZ-KJ12NA MFZ-KJ15NA MFZ-KJ18NA
NOTE: Turn OFF the power supply before disassembly.
OPERATING PROCEDURE PHOTOS
1. Removing the panel
(1) Push down the tabs on the both sides of the unit.
(2) Open the front panel toward you and pull it out
upwards.
(3) Remove the screws of the panel.
(4) Open the horizontal vane (back) and push the
marks on the top of the panel, and pull the panel
toward you.
(5) Lift up the panel and remove it from the unit.
Photo 1
Photo 2
Tabs of the unit
Push the
marks.
2. Removing the electrical box
(1) Remove the panel. (Refer to 1.)
(2) Remove the screw of the V.A. clamp cover and
remove the V.A. clamp cover.
(3) Remove the screw of the electrical cover and remove
the electrical cover.
(4) Remove the screw of the indoor/outdoor connecting
wire, and then the indoor/outdoor connecting wire.
(5) Remove the screws of the conduit box, and remove
the conduit box.
(6) Remove the earth wire connected to the indoor heat
exchanger. (Photo 4)
(7) Remove the screw of the electrical box. (Photo 5)
(8) Disconnect the following connectors on the electronic
control P.C. board.
• Fan motor connector < CN211> (Photo 5)
•
Indoor coil thermistor connector < CN112>
(9) Rotate the display receiver P.C. board holder to the
right side and disconnect the vane motor relay con-
nector. (Photo 6)
(
10
) Disengage the electrical box from the upper catch
and pull out the electrical box from the box.
(Photo 5)
Screw of the
panel
Photo 3
Screw of the
electrical cover
Screw of the
V.A. clamp cover
36
Screws of the
conduit box
Conduit box
Screw of the
panel
OPERATING PROCEDURE PHOTOS
OBH752A
3. Removing the electronic control P.C. board and
the display receiver P.C. board
(1) Remove the panel. (Refer to 1.)
(2) Remove the electrical box. (Refer to 2.)
(3) Remove the earth wire connected to the electronic
control P.C. board.
(4) Disconnect all the connectors on the electronic con-
trol P.C. board.
(5) Pull out the electronic control P.C. board from the
electrical box.
(6) Disengage the catches on the lead guide.
(7) Disengage the display receiver P.C. board holder from
the catch on the electrical box.
(8) Open the display receiver P.C. board holder and pull
out the display receiver P.C. board.
Attaching the connectors
Run the lead wires with the connectors as they were
before the disassembly.
4. Removing the nozzle assembly
(1) Remove the panel. (Refer to 1.)
(2) Rotate the display receiver P.C. board holder to the
right side and disconnect the vane motor relay con-
nector.
(3) Remove the fixed screws on the both sides of the
nozzle.
(4) Disengage the catches on the nozzle from the box.
(5) Hold the both sides of the nozzle. Rotate the nozzle
toward you around the right and left ribs to remove it.
Photo 4
Earth wire connect to
the heat exchanger
Photo 5
Earth wire
connect to the
indoor electronic
control P.C. board
Indoor coil
thermistor
connector CN112
Photo 7
Photo 8
Catches on the display
receiver P.C. board holder
Catches on
the lead guide
Lamp cover
Display receiver
P.C. board
Fan motor
connector CN211
Photo 6
Display receiver
P.C. board
connector CN1J1
Vane motor
Connector CN151
Screw of the
electrical box
Vane motor relay
connector
Catch on the display receiver P.C.
board holder and
the electrical box
Display receiver
P.C. board
37
How to remove the multi-flow
OBH752A
vane and the horizontal vanes
(1) Removing the horizontal vane (front/back)
Horizontal vane (back)
Horizontal vane (front)
Unit body
(1)-1. See the figure below and push to open the indicated
places on the horizontal vanes (between front and back)
with your fingers so that you can access 4 vane shafts
positioned on the back of the horiz ontal vanes.
(vane shafts on each horizontal vane)
Va
ne shafts
Multi-flow vane
(2) Removing the multi-flow vane
(2)-1.Open the hori zontal vanes (f ront and back) by following (1)-1.
Make sure that 3 vane shafts are on the back of the multi-flow vane.
Vane shafts
Multi-flow vane
Top down view from the back of the unit
(1)-2. Insert a tool such as a precision screwdriver
in the opening on the vane shaft and lift the catch
of the vane s ha
from the rib on the horiz ontal vane. Slide the vane shaf t
in arrow 2 direction and separate it from the unit body.
(1)-3. Remove the axial rods on the both ends of the
horizontal vane from the unit body.
ft in arrow 1 direction to detach it
Unit body
Vane shaft
Opening
Catch
Horizontal vane
Rib
(2)-2. Insert a tool such as a precision screwdriver in the gap
between multi-flow vane and the vane shaft and lift the catch
of the vane shaft in the arrow 1 direction to detach it from the rib
on the multi-flow vane. Slide the vane shaft in arrow 2 direction
and separate it from the unit body.
Catch
Rib
Multi-flow vane
(2)-3. Remove the axial rod on the one end of the multi-flow
vane f rom the unit body.
Vane shaft
Unit body
38
OPERATING PROCEDURE PHOTOS
OBH752A
5. Removing the horizontal vane motor
(1) Remove the panel. (Refer to 1.)
(2) Remove the screws of the horizontal vane motor sup-
port and pull out the horizontal vane motor support
from the nozzle.
(3) Remove the screws of the horizontal vane motors.
(4) Remove the horizontal vane motors from the horizon-
tal vane motor support.
(5) Disconnect the connectors from the horizontal vane
motor.
Installing the horizontal vane motor
Connect the connectors to the horizontal vane motors
by referring to the colors, red and white, noted on the
vane motor support.
6. Removing the multi-flow vane motor unit
(1) Remove the panel. (Refer to 1.)
(2) Disconnect the connector from the multi-flow vane
motor unit.
(3) Remove the screws of the multi-flow vane motor unit
and pull out the multi-flow vane motor unit from the
nozzle.
Photo 9
Screws of the nozzle
Catches
Water cover
Photo 10
Catch Catch
Photo 12
Photo 11
Screws of the horizontal
vane motor support
Screws of the multi-flow vane motor unit
Rib
Screws of the horizontal
vane motors
Rib
39
OPERATING PROCEDURE PHOTOS
OBH752A
7. Removing the line flow fan and the indoor fan
motor
(1) Remove the panel. (Refer to 1.)
(2) Remove the electrical box. (Refer to 2.)
(3) Remove the nozzle. (Refer to 4.)
(4) Disengage the water cover from the catches. (Photo 9)
(5) Remove the screws fixing the motor bed.
(6) Loosen the screw fixing the line flow fan.
(7) Remove the motor bed together with the indoor fan
motor and the motor band.
(8) Disengage the catches on the motor band and remove
the motor band, and pull out the indoor fan motor.
(9) Remove the screws fixing the both sides of the heat
exchanger.
(10) Disengage the catch on the right side on the heat
exchanger.
(11) Lift the heat exchanger, and pull out the line flow fan
upward.
Photo 16
Photo 13
Screw of the line flow fan
Photo 14
Screws of the motor bed
Photo 17
Screw of the
heat exchanger
Catches of the
heat exchanger
Photo 15
Screws of the
heat exchanger
40
OBH752A
41
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
© Copyright 2016 MITSUBISHI ELECTRIC CORPORATION
Distributed in Mar. 2016. No. OBH752 REVISED EDITION-A
Distributed in Feb. 2016. No. OBH752
Made in Japan
New publication, effective Mar. 2016
Specifications are subject to change without notice.
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