MITSUBISHI ELECTRIC NAXWEL09A112AA Electric Mr Slim Air Conditioner Remote Control User Manual

INDOOR UNIT
No. OBHA818
REVISED EDITION-C
SERVICE MANUAL

NAXWEL09A112AA Electric Mr Slim Air Conditioner Remote Control

Revision C:

• Remote controller P.C. board has been added. (7-2.)

OBHA818 REVISED EDITION-B is void.
Models
NAXWEL09A112AA NAXWEL09A112AB
NAXWEL12A112AA NAXWEL12A112AB
NAXWEL18A112AA
NAXWEL24A112AA

NAXWEL24A112AA
Outdoor unit service manual

NAXSEL•A112AA Series (OBHA819)
PARTS CATALOG (OBBA818)

Use the specified 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.

< Preparation before the repair service>

• Prepare the proper tools.
• Prepare the proper protectors.
• Provide adequate ventilation.
• After stopping the operation of the air conditioner, turn off the power-supply breaker and pull the power plug.
• Discharge the capacitor before the work involving the electric parts.

< Precautions during the repair service>

• Do not perform the work involving the electric parts with wet hands.
• Do not pour water into the electric parts.
• Do not touch the refrigerant.
• Do not touch the hot or cold areas in the refrigeration cycle.
• When the repair or the inspection of the circuit needs to be done without turning off the power, exercise great caution not to touch the live parts.

WARNING

• When the refrigeration circuit has a leak, do not execute pump down with the compressor.

• When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.
  The compressor may burst if air etc. get into it.

• When opening or closing the valve below freezing temperatures, refrigerant may spurt out from the gap between the valve stem and the valve body, resulting in injuries.

Revision A:

• 9-7. TEST POINT DIAGRAM AND VOLTAGE has been modified.

Revision B:

• NAXWEL09/12A112AB have been added.

Revision C:

• Remote controller P.C. board has been added. (7-2.)

TECHNICAL CHANGES

NAXWEL09A112AA
NAXWEL12A112AA
NAXWEL18A112AA
NAXWEL24A112AA
1. New model
NAXWEL09A112AA →NAXWEL09A112AB
NAXWEL12A112AA →NAXWEL12A112AB
1. Indoor electronic control P.C. board and indoor power P.C. board have been changed.

PART NAMES AND FUNCTIONS

NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB

ACCESSORIES

NAXWEL18A112AA NAXWEL24A112AA ACCESSORIES

SPECIFICATION

Indoor model| NAXWEL09A112AA NAXWEL09A112AB| NAXWEL12A112AA NAXWEL12A112AB
---|---|---
Power supply| V, phase, Hz| 208/230, 1, 60
Max. fuse size (time delay)/ Disconnect switch| A| 15
Min. circuit ampacity| A| 1.0
Fan motor| F.L.A| 0.76
Airflow
Super High – High – Med. – Low| COOL Dry
(Wet)| CFM| 399 – 321 – 237 – 170
(364 – 286 – 201 – 134)
HEAT Dry| CFM| 406 – 321 – 237 – 170
Moisture removal| pt./h| 1.5| 2.5
Sound level
Super High – High – Med. – Low| Cooling| dB(A)| 43 – 37 – 30 – 22| 45 – 37 – 30 – 22
Heating| dB(A)| 43 – 37 – 30 – 22
Fan speed
Super High – High – Med. – Low| Cooling| rpm| 1,020 – 860 – 670 – 530
Heating| rpm| 1,040 – 860 – 670 – 530
Cond. drain connection O.D.| in.| 5/8
Dimensions| W| in.| 31-7/16
D| 9-1/8
H| 11-5/8
Weight| Ib.| 22
External finish| Munsell 1.0Y 9.2/0.2
Control voltage (by built-in transformer)| 12 – 24 V DC

NOTE: Test conditions are based on AHRI 210/240.

Airflow
Super High – High – Med. – Low| COOL Dry (Wet)| CFM| 625 – 530 – 431 – 328
(562 – 477 – 388 – 295)| 702 – 530 – 431 – 353
(632 – 477 – 388 – 318)
HEAT Dry| CFM| 625 – 530 – 431 – 307| 702 – 579 – 448 – 346
Moisture removal| pt./h| 2.1| 2.3
Sound level
Super High – High – Med. – Low| Cooling| dB(A)| 47 – 42 – 37 – 30| 50 – 44 – 38 – 33
Heating| dB(A)| 47 – 42 – 37 – 30| 50 – 44 – 38 – 32
Fan speed
Super High – High – Med. – Low| Cooling| rpm| 1,140 – 1,000 – 850 – 690| 1,250 – 1,000 – 850 – 730
Heating| rpm| 1,140 – 1,000 – 850 – 660| 1,250 – 1,070 – 880 – 720
Cond. drain connection O.D.| in.| 5/8
Dimensions| W| in.| 36-5/16
D| 9-13/16
H| 12
Weight| Ib.| 28
External finish| Munsell 1.0Y 9.2/0.2
Control voltage (by built-in transformer)| 12 – 24 V DC

NOTE: Test conditions are based on AHRI 210/240.

3-1. OPERATING RANGE

1. POWER SUPPLY
   | Rated voltage| Guaranteed voltage (V)
   ---|---|---
   Indoor unit| 208/230 V
   1 phase
   60 Hz|
2. OPERATION
   Mode| Condition| Intake air temperature (°F)
   ---|---|---
   DB| WB
   Cooling| Standard temperature| 80| 67
   Maximum temperature| 90| 73
   Minimum temperature| 67| 57
   Maximum humidity| 78%
   Heating| Standard temperature| 70| 60
   Maximum temperature| 80| 67
   Minimum temperature| 70| 60

3-2. OUTLET AIR SPEED AND COVERAGE

Model| Mode| Function| Airflow
(CFM)| Air speed (ft./s.)| Coverage (ft.)
---|---|---|---|---|---
NAXWEL09A112AA NAXWEL09A112AB| HEAT| Dry| 406| 20.6| 29.5
COOL| Dry| 321| 16.3| 23.5
Wet| 286| 14.5| 21.0
NAXWEL12A112AA NAXWEL12A112AB| HEAT| Dry| 406| 20.6| 29.5
COOL| Dry| 321| 16.3| 23.5
Wet| 286| 14.5| 21.0
NAXWEL18A112AA| HEAT| Dry| 625| 28.5| 42.6
COOL| Dry| 625| 28.5| 42.6
Wet| 562| 25.6| 38.4
NAXWEL24A112AA| HEAT| Dry| 702| 32.0| 47.7
COOL| Dry| 702| 32.0| 47.7
Wet| 632| 28.8| 43.1

• 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.

OUTLINES AND DIMENSIONS

NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB

NAXWEL18A112AA

NAXWEL24A112AA

WIRING DIAGRAM

NAXWEL09A112AA NAXWEL12A112AA

NAXWEL09A112AB NAXWEL12A112AB

NAXWEL18A112AA NAXWEL24A112AA

REFRIGERANT SYSTEM DIAGRAM

NAXWEL09A112AA NAXWEL09A112AB
NAXWEL12A112AA NAXWEL12A112AB

NAXWEL18A112AA NAXWEL24A112AA

SERVICE FUNCTIONS

NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB NAXWEL18A112AA NAXWEL24A112AA
7-1. TIMER SHORT MODE
For service, the set time can be shortened by bridging of the timer short point on the indoor electronic control P.C. board.
The time will be shortened as follows. (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. REMOTE CONTROLLER P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, the remote controller P.C. boards must be modified according to the number of the indoor unit.
NOTE: For modification, take out the batteries and press the STOP/OPERATE (OFF/ON) button 2 or 3 times at first.
How to modify the remote controller P.C. board Remove batteries before modification.
The board has one of the following prints:The remote controller P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.
After modification, press the RESET button.
Table 1

| 1 unit operation| 2 units operation| 3 units operation| 4 units operation
---|---|---|---|---
No. 1 unit| No modification| Same as at left| Same as at left| Same as at left
No. 2 unit| —| Solder J1| Same as at left| Same as at left
No. 3 unit| —| —| Solder J2| Same as at left
No. 4 unit| —| —| —| Solder both J1 and J2

How to set the remote controller exclusively for particular indoor unit
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote controller for the indoor unit.
The indoor unit will only accept the signal from the remote controller that has been assigned to the indoor unit once they are set.
The setting will be cancelled if the breaker is turned OFF, or the power supply is shut down.
Please conduct the above setting once again after the power has been restored.

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 shut-off of the main power.
Operation

1. If the main power has been cut, the operation settings remain.
2. 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”

1. Turn OFF the main power of the unit.
2. Solder the Jumper wire JR07 on the indoor electronic control P.C. board. (NAXWEL09/12A112AA, NAXWEL09/12A112AB) Cut the Jumper wire JR77 on the indoor electronic control P.C. board. (NAXWEL18/24A112AA) (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 cancelled.
• If the unit has been turned 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 the breaker from tripping 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.

MICROPROCESSOR CONTROL

NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB NAXWEL18A112AA NAXWEL24A112AA
WIRELESS REMOTE CONTROLLER

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| About 4°F (2°C) or more away from set temperature
  | The room temperature is approaching the set tem- perature| About 2 to 4 °F (1° to 2°C) from set temperature

Lit
Blinking
Not lit
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 (TOO WARM or TOO COOL button) to select the desired temperature.
   The setting range is 61 – 88°F (16 – 31°C).

4. 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.

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.

4. Coil frost prevention
   Coil frost prevention works the same way as that in COOL mode. (8-1.1.)

8-3. 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 (TOO WARM or TOO COOL button) to select the desired temperature.
   The setting range is 61 – 88°F (16 – 31°C).

4. 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.

5. 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. The indoor fan operates following the cold air prevention control.
   This mode continues until the temperature of indoor heat exchanger falls.

6. 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.

8-4. AUTO VANE OPERATION

1. Horizontal vane
   (1) Vane motor drive
   These models are equipped with a stepping motor for the horizontal vane. 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.(3) Positioning
   To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the selected angle.
   Confirmation 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.
   (4) VANE AUTO ( ) mode
   In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room temperature distribution.
   NAXWEL09/12A112AA, NAXWEL09/12A112AB
   In COOL and DRY operation
   Vane angle is fixed to Horizontal position. In HEAT operation
   Vane angle is fixed to Angle 5. NAXWEL18/24A112AA
   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 0.5 – 1 hour, the vane angle automatically changes to Angle 2 for dew prevention.
   (7) SWING ( ) mode
   By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically.
   (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.
   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.
   ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL button is pressed or change to other operation mode.

8-5. TIMER OPERATION (ON/OFF TIMER)

1. How to set the timer
   (1) Press STOP/OPERATE (OFF/ON) button to start the air conditioner.
   (2) Select the timer mode by pressing the button during operation.
   Each time this button is pressed, the timer mode is changed in sequence:
   (OFF TIMER) → (ON TIMER) → TIMER RELEASE
   (3) Set the time of the timer using the button.
   Each time this button is pressed, the set time increase or decrease by 1 hour to 12 hours.

2. To release the timer
   Press the button until (OFF TIMER) and  (ON TIMER) are not displayed.

NOTE :

• The OFF TIMER and the ON TIMER cannot be set at the same time.
• The displayed time is the time remaining and will decrease in 1-hour increments as time passes.

8-6. EMERGENCY/TEST OPERATION
In the case of test run operation or emergency operation, use the 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.
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 Med.
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 the 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 the emergency operation switch during normal operation.

The operation mode is indicated by the Operation Indicator lamp as follows:
Operation Indicator lamp

8-7. 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.\

8-8. 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 fine-tipped object.

TROUBLESHOOTING

NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB
NAXWEL18A112AA NAXWEL24A112AA
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 unit first with the remote controller, and then after confirm- ing 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. First, check if the OPERATION INDICATOR lamp on the indoor unit is blinking ON and OFF to indicate an abnormality.
   To make sure, check how many times the OPERATION INDICATOR lamp is blinking ON and OFF before starting service work.
2. Before servicing, verify that all connectors and terminals are connected properly.
3. When the electronic control P.C. board seems to be defective, check for disconnection of the copper foil pattern and burnt or discolored components.
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.
   1. Remove the back lid and insert batteries.
   Then reattach the back lid. 2. Press RESET button with a fine-tipped object, 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 microprocessor when batteries are replaced.
   This function is equipped to prevent the microprocessor from malfunctioning due to the voltage drop caused by the battery replacement.

3. Do not use the leaking batteries.

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 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:
2. Table of indoor unit failure mode recall function****
   Upper lamp of OPERATION
   INDICATOR lamp| Abnormal point
   (Failure mode)| Condition| Remedy
   ---|---|---|---
   Not lit| Normal| —| —
   1-time blink 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 blink
   2.5-second OFF| Indoor coil ther mistor| 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 blink
   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 blink
   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 blink
   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.).

9-3. INSTRUCTION OF TROUBLESHOOTING

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 blinks.

OPERATION INDICATOR

No.| Abnormal
point| Operation indicator lamp| Symptom| Condition| Remedy
---|---|---|---|---|---
1| Miswiring or serial signal| Upper lamp blinks.
0.5-second ON| 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.  D “How to check
miswiring and serial signal error”.
2| Indoor coil thermistor
Room temperature
thermistor| Upper lamp blinks.
2-time blink| The indoor coil or the room temperature thermistor is short or open circuit.| • Refer to the characteristics of
indoor coil thermistor, and the
room temperature thermistor
(9-7.).
3| Indoor fan motor| Upper lamp blinks.
3-time blink| The rotational frequency feedback signal is not emitted during the indoor fan operation.| • Refer to 9-6.  A “Check of in-
door fan motor”.
4| Indoor control
system| Upper lamp blinks.
4-time blink| 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
system| Upper lamp blinks.
5-time blink| It consecutively occurs 3 times that the compressor
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| Upper lamp blinks.
6-time blink| 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
system| Upper lamp blinks.
7-time blink| It cannot properly read data in the nonvolatile memory of the inverter P.C. board or the outdoor 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 abnormality| Upper lamp blinks.
14-time blink or more| 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
system| Upper 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.| • Check the blinking pattern of
the LED on the inverter P.C.
board or the outdoor electronic
control P.C. board.

9-5. TROUBLESHOOTING CRITERION OF MAIN PARTS
NAXWEL09A112AA NAXWEL09A112AB NAXWEL12A112AA NAXWEL12A112AB
NAXWEL18A112AA NAXWEL24A112AA

Measure the resistance with a multimeter.
Refer to 9-7. “TEST POINT DIAGRAM AND VOLTAGE”, 1 or 2. “Indoor electronic control P.C. board”, for the chart of thermistor.|
Indoor fan motor (MF)| Check 9-6.|
Horizontal vane motor (MV)| Measure the resistance between the terminals with a multimeter.
(Part temperature 50 – 86°F (10 – 30°C))|

9-6. TROUBLESHOOTING FLOW
A Check of indoor fan motor
The indoor fan motor error has occurred, and the indoor fan does not operate.

B Check of remote controller and indoor electronic control P.C. board
Check if the remote controller is exclusive for this air conditioner.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 difficult to see the illuminated LED of the signal transmitting section with a smartphone camera.
*2 If the inverter fluorescent light is turned on when the room is cool, the unit may have difficulty receiving the signal from the remote controller or may not be able to operate with it; if the inverter fluorescent light is turned on when the room is warm, the unit may be able to operate with the remote controller.

C Check of indoor P.C. board and indoor fan motor NAXWEL09/12A112AA
NAXWEL09/12A112AB NAXWEL18/24A112AA

D How to check miswiring and serial signal error * 1. Miswiring may damage indoor electronic control P.C. board during the operation.
Be sure to confirm the wiring is correct before the operation starts.

• 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 or the outdoor electronic control P.C. board is normal, LED blinks 6 times after 3 minutes. (Except for outdoor unit of multi system type)

NAXWEL18/24A112AA * 1. Miswiring may damage indoor electronic control P.C. board during the operation.
Be sure to confirm the wiring is correct before the operation starts.

• 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 or the outdoor electronic control P.C.
     board is normal, LED blinks 6 times after 3 minutes. (Except for outdoor unit of multi system type)

E Electromagnetic noise enters into TV sets or radios Even if all of the above conditions are fulfilled, the electromagnetic noise may enter, depending on the electric field strength or the installation condition (combination of specific conditions such as antennas or wiring).
Check the followings 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, grounding wire, antennas, wiring from antennas, receiver
5. Electric field intensity of the broadcast station affected by the electromagnetic noise
6. Presence or absence of amplifier 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.

9-7. TEST POINT DIAGRAM AND VOLTAGE
NAXWEL09A112AA NAXWEL12A112AA

NAXWEL09A112AB NAXWEL12A112AB
1. Indoor power P.C. board, Indoor terminal P.C. board

NAXWEL18A112AA NAXWEL24A112AA

DISASSEMBLY INSTRUCTIONS