MSZ-HJ·VA HJ50VA | MSZ-HJ50VA | MSZ-HJ·VA HJ35VA | Mitsubishi Electric MSZ-HJ·VA HJ25VA, HJ35VA, HJ50VA split-type air conditioner SERVICE MANUAL

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Mitsubishi Electric MSZ-HJ25VA - E1, MSZ-HJ35VA - E1, MSZ-HJ50VA - E1 SERVICE MANUAL | Manualzz

SPLIT-TYPE AIR CONDITIONERS

INDOOR UNIT

SERVICE MANUAL

Models

MSZ-HJ25VA

-

E1

MSZ-HJ35VA

-

E1

MSZ-HJ50VA

-

E1

Revision A:

• MSZ-HJ50VA-

E1

has been added.

Please void OBH647.

No. OBH647

REVISED EDITION-A

NOTE:

RoHS compliant products have <G> mark on the spec name plate.

Outdoor unit service manual

MUZ-HJ·VA Series (OBH648)

CONTENTS

1. TECHNICAL CHANGES ··································· 3

2. PART NAMES AND FUNCTIONS ····················· 4

3. SPECIFICATION ················································ 5

4. NOISE CRITERIA CURVES ······························ 6

5. OUTLINES AND DIMENSIONS ························ 7

6. WIRING DIAGRAM ············································ 7

7. REFRIGERANT SYSTEM DIAGRAM ··············· 8

8. SERVICE FUNCTIONS ····································· 9

9. MICROPROCESSOR CONTROL ····················11

10. TROUBLESHOOTING ····································· 15

11. DISASSEMBLY INSTRUCTIONS ···················· 27

PARTS CATALOG (OBB647)

Use the specifi ed refrigerant only

Never use any refrigerant other than that specified.

Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.

Correct refrigerant is specified in the manuals and on the spec labels provided with our products.

We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions.

<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 remove 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.

Revision A:

• MSZ-HJ50VAE1 has been added.

OBH647A 2

1 TECHNICAL CHANGES

MSZ-HJ25VA -

E1

MSZ-HJ35VA -

E1

MSZ-HJ50VA -

E1

1. New model

OBH647A 3

2 PART NAMES AND FUNCTIONS

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

Front panel

Air filter

Air inlet

Horizontal vane

Air outlet

Remote controller

Heat exchanger

Emergency operation switch

Remote control receiving section

Operation indicator lamp

Emergency operation switch

ACCESSORIES

Installation plate

Installation plate fi xing screw 4 × 25 mm

Battery (AAA) for remote controller

Wireless remote controller

Felt tape (Used for left or left-rear piping)

2

1

1

5

1

OBH647A 4

3 SPECIFICATION

Breaker Capacity

Running current 1

(Total)

Starting current 1 (Total)

Model

Indoor model

Power supply

Power input 1 (Total)

Power factor 1 (Total)

MSZ-HJ25VA

A

Cooling

Heating

W

730

870

Cooling 3.7

A

Heating 4.2

Cooling

Heating

%

A

85

90

4.2

Current 1

Cooling

Heating

A

0.19

0.20

Dimensions W × H × D

Weight

Air direction mm kg

Super High

High

Med.

Low

Super High

High

Med.

Low

Super High

High

Med.

Low

Super High

High

Med.

Low

Super High

High

Med.

Low

Super High

High

Med.

Low m3/h m3/h dB(A) dB(A) rpm rpm

880

710

550

1,120

900

710

520

37

30

22

43

37

30

23

1,080

571

438

328

227

598

451

328

208

43

Fan speed regulator

Remote controller model

MSZ-HJ35VA

10

Single phase 230 V, 50 Hz

1,040

995

4.9

4.8

92

90

4.9

RC0J40-EF

0.24

0.22

799 × 290 × 232

9

5

654

470

341

227

619

451

328

208

45

930

730

550

1,150

900

710

520

38

31

22

44

37

30

23

1,200

4

MP13A

NOTE : Test conditions are based on ISO 5151.

Cooling : Indoor Dry-bulb temperature 27°C

Outdoor Dry-bulb temperature 35°C

Heating : Indoor Dry-bulb temperature 20°C

Outdoor Dry-bulb temperature 7°C

1 Measured under rated operating frequency.

Wet-bulb temperature 19°C

Wet-bulb temperature 6°C

Specifications and rated conditions of main electric parts

Fuse (F11)

Horizontal vane motor (MV)

Varistor

Terminal block

(NR11)

(TB)

T3.15AL250V

12 VDC

S10K320E3K1 (ERZV14D471)

5P

1,000

860

660

1,220

1,000

800

640

40

36

28

47

41

34

27

1,120

772

667

547

380

861

667

497

364

45

MSZ-HJ50VA

12

2,050

1,480

9.0

6.6

99

97

9.0

0.27

0.34

5 OBH647A

4 NOISE CRITERIA CURVES

MSZ-HJ25VA

FAN SPEED FUNCTION SPL(dB(A))

Super High

COOLING

HEATING

43

43

LINE

90

80

MSZ-HJ35VA

FAN SPEED

Super High

FUNCTION SPL(dB(A))

COOLING 45

HEATING 44

LINE

90

70

NC-70

60

NC-60

50

NC-50

40

NC-40

30

NC-30

20

10

63

NC-20

NC-10

125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

80

70

NC-70

60

NC-60

50

NC-50

40

NC-40

30

NC-30

20

10

63

NC-20

NC-10

125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

MSZ-HJ50VA

FAN SPEED FUNCTION SPL(dB(A))

Super High

COOLING

HEATING

45

47

LINE

90

80

70

NC-70

60

NC-60

50

NC-50

40

NC-40

30

NC-30

20

10

63

NC-20

NC-10

125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

OBH647A

6

Test conditions

Cooling : Dry-bulb temperature 27°C Wet-bulb temperature 19°C

Heating : Dry-bulb temperature 20°C

INDOOR UNIT

1m

0.8m

MICROPHONE

WALL

5 OUTLINES AND DIMENSIONS

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

11×26 Oblong hole

Installation plate

Indoor unit

80.5

799

785 7

225 225

Unit : mm

11×20 Oblong hole

80.5

5 232

20 or more

In case of left, left back,or left under piping (using spacer), 108.5 or more

40 or more

61.5

338

167 157

340

Air in

59.5

Wall hole Φ 65

Installation plate

Piping

57

41

18

49

69

630

57

80

120

Air out

(57°)

130

172

42

103

Drain hose

MSZ-HJ25/35VA

Insulation Φ35 O.D

Liquid line Φ6.35 - 0.39m (Flared connection Φ6.35)

Gas line Φ9.52 - 0.34m (Flared connection Φ9.52)

Drain hose InslationΦ28 Connected part Φ16 O.D active length 370

MSZ-HJ50VA

Insulation Φ37 O.D

Liquid line Φ6.35 - 0.39m (Flared connection Φ6.35)

Gas line Φ9.52 - 0.34m (Flared connection Φ12.7)

Drain hose InslationΦ28 Connected part Φ16 O.D active length 370

6 WIRING DIAGRAM

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

OBH647A

7

7 REFRIGERANT SYSTEM DIAGRAM

MSZ-HJ25VA MSZ-HJ35VA

Indoor heat exchanger

Refrigerant pipe ø9.52

(with heat insulator)

Indoor coil thermistor

RT12

Flared connection

Indoor coil thermistor

RT13

Room temperature thermistor

RT11

Flared connection

Refrigerant pipe ø6.35

(with heat insulator)

Refrigerant flow in cooling

Refrigerant flow in heating

MSZ-HJ50VA

OBH647A

Indoor heat exchanger

Refrigerant pipe ø12.7

(with heat insulator)

Indoor coil thermistor

RT12

Flared connection

Indoor coil thermistor

RT13

Room temperature thermistor

RT11

Flared connection

Refrigerant pipe ø6.35

(with heat insulator)

Refrigerant flow in cooling

Refrigerant flow in heating

8

Unit : mm

8 SERVICE FUNCTIONS

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

8-1. TIMER SHORT MODE

For service, the following set time can be shortened by short circuiting the timer short mode point on the electronic control

P.C. board. (Refer to 10-7.)

Set time : 3-minute

→ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is shortened by short circuiting the timer short mode point.)

8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION

A maximum of 4 indoor units with wireless remote controllers can be used in a room.

In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be modified according to the number of the indoor unit.

How to modify the remote controller P.C. board

Remove batteries before modification.

The board has a print as shown below :

J1 J2

NOTE : For modification, take out the batteries and press the OPERATE/STOP (ON/

OFF) button 2 or 3 times at first.

After finish modification, put back the batteries then press the RESET button.

The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.

After modification, press the RESET button.

Table 1

No. 1 unit

No. 2 unit

No. 3 unit

No. 4 unit

1 unit operation

No modifi cation

2 units operation

Same as at left

Solder J1

3 units operation

Same as at left

Same as at left

Solder J2

4 units operation

Same as at left

Same as at left

Same as at left

Solder both J1 and J2

How to set the remote controller exclusively for particular indoor unit

After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote controller for the indoor unit.

The indoor unit will only accept the signal from the remote controller that has been assigned to the indoor unit once they are set.

The setting will be cancelled if the breaker has turned OFF, or the power supply has shut down.

Please conduct the above setting once again after the power has restored.

OBH647A 9

8-3. AUTO RESTART FUNCTION

When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in the same mode just before the shutoff of the main power.

Operation

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

After the power is restored, the unit restarts automatically according to the memory.

(However, it takes at least 3 minutes for the compressor to start running.)

How to disable “AUTO RESTART FUNCTION”

Turn off the main power for the unit.

Cut the Jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 10-7.)

Indoor electronic control P.C. board

JR77

CN112

CN110

NOTE:

• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote controller.

• If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is cancelled.

• If the unit has been off with the remote controller before power failure, the auto restart function does not work as the power button of the remote controller is off.

• To prevent breaker OFF due to the rush of starting current, systematize other home appliance not to turn ON at the same time.

• When some air conditioners are connected to the same supply system, if they are operated before power failure, the starting current of all the compressors may flow simultaneously at restart.

Therefore, the special counter measures are required to prevent the main voltage-drop or the rush of the starting current by adding to the system that allows the units to start one by one.

OBH647A 10

9 MICROPROCESSOR CONTROL

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Operation display section

ON/OFF (operate/stop) button

Fan speed control button

Operation select button

Timer mode select button

Temperature buttons

ECONO COOL button

Vane control button

Time set buttons

RESET button

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 2°C or more away from set temperature

Lighted

Blinking

Not lighted

The room temperature is approaching the set temperature

About 1 to 2°C from set temperature

9-1. COOL ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) 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 16 ~ 31°C.

1. Coil frost prevention

The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil from frosting.

When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works. The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor heat exchanger rises.

11 OBH647A

9-2. DRY ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) 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 is as same as COOL mode. (9-1.1.)

9-3. HEAT ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) 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 16 ~ 31°C.

1. Cold air prevention control

When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room 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.

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

3. Defrosting

Defrosting starts when the temperature of outdoor heat exchanger becomes too low.

The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.

This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.

9-4. 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.

AUTO 1 2 3 4 5 SWING

(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.

Confirming of standard position is performed in the following cases:

(a) When the operation starts or finishes (including timer operation).

(b) When the test run starts.

(4) VANE AUTO ( ) mode

In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room temperature distribution.

In COOL and DRY operation

Vane angle is fixed to Horizontal position.

In HEAT operation

Vane angle is fixed to Angle 4.

Horizontal position

OBH647A 12

(5) STOP (operation OFF) and ON TIMER standby

In the following cases, the horizontal vane returns to the closed position.

(a) When OPERATE/STOP (ON/OFF) 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 3 ~ 5 when the compressor cumulative operation time exceeds 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.

(9) To change the airfl ow direction not to blow directly onto your body.

To change the airfl ow direction

When to use this function?

COOL/DRY HEAT

Pressing and holding

VANE CONTROL button for 2 seconds or more

Use this function if you do not want the air from the indoor unit to

The air conditioner starts the cooling or drying operation approximately 3 minutes after the vane cause the horizontal vane blow directly onto your has moved to the horizontal posito reverse and move to horizontal position.

body.

• Depending on the shape of the room, the air may blow tion.

• When VANE CONTROL button is pressed again, the vane returns to the previously-set position and

The air conditioner starts heating operation approximately 3 minutes after the vane has moved to the horizontal position.

• Sometimes the area around your feet may not warm. To warm the area around the feet, set the horizontal vane to (AUTO) or the

Horizontal position directly onto your body.

• Press VANE CON-

TROL button again to return the vane to the previously-set position. the air conditioner starts the cool or dry operation in approximately

3 minutes. downward-blowing position.

• When VANE CONTROL button is pressed again, the vane returns to the previously-set position and the air conditioner starts the heat operation in approximately 3 minutes.

NOTE :

• If you make the airfl ow not to blow directly onto your body by pressing VANE CONTROL button, the compressor stops for 3 minutes even during the operation of the air conditioner.

• The air conditio ner operates with Very Low speed until the compressor turns on again.

(10) ECONO COOL ( ) operation (ECONOmical operation)

When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 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.

9-5. TIMER OPERATION (ON/OFF TIMER)

1. How to set the timer

(1) Press OPERATE/STOP (ON/OFF) 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

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.

OBH647A 13

9-6. EMERGENCY/TEST OPERATION

In 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, has failed or the batteries of the remote controller run down. The unit will start and OPERATION INDICATOR lamp will light.

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

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 EMERGENCY OPERATION switch is pressed once or twice or the unit receives any signal from the remote controller. In case of latter, normal operation will start.

NOTE: Do not press EMERGENCY OPERATION switch during normal operation.

Operation mode COOL

Set temperature

Fan speed

Horizontal vane

24°C

Med.

Auto

HEAT

24°C

Med.

Auto

The operation mode is indicated by the

Operation Indicator lamp as following

Operation Indicator lamp

EMERGENCY OPERATION switch

EMERGENCY COOL

↓ Lighted

EMERGENCY HEAT

STOP

9-7. 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.

OBH647A 14

10 TROUBLESHOOTING

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

10-1. CAUTIONS ON TROUBLESHOOTING

1. Before troubleshooting, check the following:

1) Check the power supply voltage.

2) Check the indoor/outdoor connecting wire for miswiring.

2. Take care of the following during servicing

1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after confirming the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug.

2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the P.C. board.

3) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.

4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.

<Incorrect> <Correct>

Lead wiring Housing point

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 10-2, 10-3 and 10-4.

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 back lid and insert batteries.

Then reattach the back lid.

Press RESET button with a thin instrument, and then use the remote controller.

Insert the minus pole of the batteries first. Check if the polarity of the batteries is correct.

NOTE: 1. If RESET button is not pressed, the remote controller may not operate correctly.

2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.

This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by the battery replacement.

3. Do not use the leaking batteries.

OBH647A 15

10-2. 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 (10-4.) 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

The cause of abnormality cannot be found because the abnormality does not recur.

Setting up the failure mode recall function

Turn ON the power supply.

<Preparation of the remote controller>

While pressing both OPERATION SELECT button and TOO COOL button on the remote controller at the same time, press RESET button.

First, release RESET button.

Hold down the other two buttons for another 3 seconds. Make sure that the indicators on the LCD screen shown in the right fi gure are all displayed. Then release the buttons.

Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature is displayed) with the remote controller headed towards the indoor unit. 1

Does upper lamp of OPERATION INDICATOR lamp on the indoor unit blink at the interval of 0.5 seconds?

Blinks: Either indoor or outdoor unit is abnormal.

Beep is emitted at the same timing as the blinking of upper lamp of OPERATION

INDICATOR lamp. 2

Judgment of indoor/outdoor abnormality

Yes

(Blinks)

Before blinking, does upper lamp of

OPERATION INDICATOR lamp stay ON for 3 seconds?

Stays ON for 3 seconds (without beep):

The outdoor unit is abnormal.

No

Yes

No

(OFF)

The indoor unit is abnormal.

Check the blinking pattern, and identify the abnormal point with the indoor unit failure mode table. (Refer to 10-2.2)

Make sure to check at least two consecutive blinking cycles. 2

Releasing the failure mode recall function

Release the failure mode recall function by the following procedures.

Turn OFF the power supply and turn it ON again.

Press RESET button of the remote controller.

Indoor unit is normal.

But the outdoor unit might be abnormal because there are some abnormalities that can't be recalled with this way.

Confi rm if outdoor unit is abnormal according to the detailed outdoor unit failure mode recall function.

The outdoor unit is abnormal.

1. Regardless of normal or abnormal condition, a short beep is emitted once the signal is received.

Check the blinking pattern, and confi rm the abnormal point with the outdoor unit failure mode table. (Refer to outdoor unit service manual.)

Make sure to check at least two consecutive blinking cycles. 3

Repair the failure parts.

Deleting the memorized abnormal condition

After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall function" mentioned above.

Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature is displayed) with the remote controller headed towards the indoor unit.

Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.

Release the failure mode recall function according to "Releasing the failure mode recall function" mentioned above.

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:

2.5-second OFF

Blinking at 0.5second interval 2.5-second OFF

Blinking at 0.5second interval

ON

OFF

Beeps

Repeated cycle

Beeps

Repeated cycle

Beeps

Repeated cycle

3.Blinking pattern when the outdoor unit is abnormal:

Blinking at 0.5-

2.5-second OFF 3-second ON second interval

ON

OFF

No beep

Repeated cycle

Beeps

2.5-second OFF 3-second ON

No beep

Repeated cycle

Blinking at 0.5second interval

Beeps

Repeated cycle

OBH647A 16

2. Indoor unit failure mode table

Upper lamp of OP-

ERATION INDICA-

TOR lamp

Not lighted

1-time fl ash every

0.5-second

2-time fl ash

2.5-second OFF

3-time fl ash

2.5-second OFF

11-time fl ash

2.5-second OFF

12-time fl ash

2.5-second OFF

Abnormal point

(Failure mode)

Condition Remedy

Normal — —

Room temperature thermistor

The room temperature thermistor short or open circuit is detected every 8 seconds during operation.

Indoor coil thermistor

The indoor coil thermistor short or open circuit is detected every 8 seconds during operation.

Serial signal

The serial signal from outdoor unit is not received for a maximum of 6 minutes.

Indoor fan motor

Indoor control system

Refer to the characteristics of the room temperature thermistor (10-7.).

Refer to the characteristics of the main indoor coil thermistor, the sub indoor coil thermistor (10-7.).

Refer to 10-6. "How to check miswiring and serial signal error".

The rotational frequency feedback signal is not emitted for the 12 seconds after the indoor fan motor is orperated.

Refer to 10-6. "Check of indoor fan motor".

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 (10-4.).

OBH647A 17

10-3. INSTRUCTION OF TROUBLESHOOTING

Start

Indoor unit operates.

Outdoor unit does not operate.

Indoor unit operates.

Outdoor unit does not operate normally.

Indoor unit does not receive the signal from remote controller.

OPERATION INDICATOR lamp on the indoor unit is fl ashing on and off.

If blinking of OPERATION INDI-

CATOR lamp cannot be checked, it can be checked with failure mode recall function.

Outdoor unit operates only in Test Run operation.

Outdoor unit does not operate even in Test Run operation.

Unit does not operate normal operation in COOL or

HEAT mode.

Indoor unit operates, when

EMERGENCY

OPERATION switch is pressed.

Indoor unit does not operate, when

EMERGENCY

OPERATION switch is pressed.

Check room temperature thermistor.

Refer to 10-7.

"Test point diagram and voltage".

Refer to "How to check inverter/compressor".

Refer to

"Check of R.V. coil".

Refer to 10-6.

"Check of remote controller and indoor electronic control P.C. board".

1. Check indoor/outdoor connecting wire.

(Check if the power is supplied to the indoor unit.)

2. Refer to 10-6. "Check of indoor P.C. board and indoor fan motor".

"Test Run operation" means the operation within 30 minutes after EMERGENCY OPERA-

TION switch is pressed.

Refer to outdoor unit service manual.

Upper lamp

Flash on and off at 0.5-second intervals

Cause:

Indoor/Outdoor unit

• Miswiring or trouble of serial signal

Upper lamp

2-time fl ash

Cause:

Indoor unit

• Trouble of room temperature

/ indoor coil thermistor

Upper lamp

3-time fl ash

Cause:

Indoor unit

• Trouble of indoor fan motor

Upper lamp

4-time fl ash

Cause:

Indoor unit

• Trouble of indoor unit control system

Upper lamp

5-time fl ash

Cause:

Outdoor unit

• Outdoor power system abnormality

Upper lamp

6-time fl ash

Cause:

Outdoor unit

• Trouble of thermistor in outdoor unit

Upper lamp

7-time fl ash

Cause:

Outdoor unit

• Trouble of outdoor control system

Upper lamp

14-time fl ash or more

Cause:

Outdoor unit

• Other abnormality

Refer to

10-6. "How to check miswiring and serial signal error".

Check room temperature thermistor and indoor coil thermistor. Refer to

10-7."Test point diagram and voltage".

Refer to

10-6.

"Check of indoor fan motor".

Replace the indoor electronic control

P.C. board.

Refer to

"How to check inverter/compressor".

Refer to

"Check of outdoor thermistors".

Replace the inverter P.C. board or the outdoor electronic control P.C. board.

Check "Flow chart of the detailed outdoor unit failure mode recall function."

OBH647A 18

10-4. TROUBLESHOOTING CHECK TABLE

Before taking measures, make sure that the symptom reappears for accurate troubleshooting.

When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp flashes.

OPERATION INDICATOR

Lighted

Blinking

Not lighted

No.

Abnormal point

Operation indicator lamp

1

Miswiring or serial signal

Upper lamp fl ashes.

0.5-second ON

0.5-second OFF

2

3

Indoor coil thermistor

Upper lamp fl ashes.

2-time fl ash

Room temperature thermistor

2.5-second OFF

Upper lamp fl ashes.

3-time fl ash

Indoor fan motor

2.5-second OFF

4

Upper lamp fl ashes.

4-time fl ash

Indoor control system

2.5-second OFF

5

Outdoor power system

Upper lamp fl ashes.

5-time fl ash

2.5-second OFF

6

Upper lamp fl ashes.

6-time fl ash

Outdoor thermistors

2.5-second OFF

7

Outdoor control system

Upper lamp fl ashes.

7-time fl ash

2.5-second OFF

8

Other abnormality

Upper lamp fl ashes.

14-time fl ash or more

2.5-second OFF

Symptom Condition

The serial signal from the outdoor unit is not received for 6 minutes.

The indoor coil or the room temperature thermistor is short or open circuit.

The rotational frequency feedback signal is not emitted during the indoor fan operation.

The outdoor thermistors short or open circuit during the compressor operation.

• Refer to "Check of outdoor thermistor".

Refer to outdoor unit service manual.

Remedy

Refer to 10-6. "How to check miswiring and serial signal error".

Refer to the characteristics of indoor coil thermistor, and the room temperature thermistor

(10-7.).

Refer to 10-6. "Check of indoor fan motor".

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.

Indoor unit and outdoor unit do not operate.

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 inverter/compressor".

Refer to outdoor unit service manual

Check the stop valve.

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.

Replace the inverter P.C. board or the outdoor electronic control P.C. board.

Refer to outdoor unit service manual.

Check the stop valve.

Check the 4-way valve.

Confi rm 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.

OBH647A 19

10-5. TROUBLE CRITERION OF MAIN PARTS

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

Part name

Room temperature thermistor (RT11)

Check method and criterion

Measure the resistance with a tester.

Indoor coil thermistor

(RT12, RT13)

Refer to 10-7. "Test point diagram and voltage", "2. Indoor electronic control

P.C. board", for the chart of thermistor.

Indoor fan motor (MF) Check 10-6. .

Vane motor (MV)

Measure the resistance between the terminals with a tester.

(Part temperature 10 ~ 30°C)

Color of the lead wire

RED - BLK

Normal

235 ~ 255

Ω

BLK

BLK

RED

Figure

ROTOR

BLK BLK

OBH647A 20

10-6. TROUBLESHOOTING FLOW

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?

No

Yes

Remove the foreign matter and adjust the line fl ow fan.

Pay enough attention to the high voltage on the fan motor connector CN211.

Turn ON the power supply, wait 5 seconds or more, and then press

EMERGENCY OPERATION switch.

Measure the supply voltage as follows within 12 seconds after EMER-

GENCY OPERATION switch is pressed.

If more than 12 seconds passes, turn OFF the power supply and turn it

ON again, then measure the voltage.

<Indoor power P.C. board>

1. Measure the voltage between CN211 (+) and (–).

2. Measure the voltage between CN211 (+) and (–).

<Indoor electronic control P.C. board>

3. Measure the voltage between CN10A (+) and GND (–).

If more than 12 seconds passes after EMERGENCY OPERATION switch is pressed, the voltage measured at 2. above goes 0 VDC although the indoor P.C. board is normal.

Is there 325 VDC between CN211 (+) and (–) ?

No

Yes

Replace the indoor power

P.C. board.

Does the voltage between CN211

(+) and (–) on the power P.C. board rise to the range of 3 to 6 VDC within

12 seconds after EMERGENCY

OPERATION switch is pressed?

Yes

No

Yes

Does the voltage between CN10A

(+) and GND (–) on the indoor electronic control P.C. board fall to

2 V or less within 12 seconds after

EMERGENCY OPERATION switch is pressed?

No

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)

Measure the voltage CN10A

No

(Changed)

(+) and GND (–) on the indoor electronic control P.C board when the fan motor is rotaring.

Replace the indoor fan motor.

Replace the indoor power P.C. board.

Yes

(Unchanged)

Is it unchanged holding

0 or 5 VDC?

No

(Changed)

Replace the indoor electronic control P.C. board.

OBH647A 21

B Check of remote controller and indoor electronic control P.C. board

Check if the remote controller is exclusive for this air conditioner.

Press OPERATE/STOP (ON/OFF) button on the remote controller.

Is LCD display on the remote controller visible?

Yes

No

(Not clear)

Replace the batteries. (Refer to 10-1.4.)

Remove the batteries, then set them back and press RESET button. (Refer to 10-1.4.)

Check if the unit operates with the remote controller.

Does the unit operate with the remote controller?

Yes

OK

No

Turn ON a radio to AM and press OP-

ERATE/STOP (ON/OFF) button on the remote controller.

Is noise heard from radio?

Yes

Are there any fl uorescent lights of inverter or rapid-start type within the range of 1 m.?

No

No

Yes

Replace the indoor electronic control

P.C. board. (Including the receiver)

Replace the remote controller.

• Reinstall the unit away from lights.

• Attach a fi lter on receiving part.

OBH647A 22

C Check of indoor P.C. board and indoor fan motor

Turn OFF the power supply.

Remove indoor fan motor connector CN211 from indoor power P.C. board and vane motor connector CN151 from the indoor electronic control P.C. board and turn ON the power supply.

Measure the resistance of indoor fan motor.

Refer to 10-5.

Short circuit:

Replace the indoor fan motor.

Does the unit operate with the remote controller?

Does OPERATION INDICATOR lamp light up by pressing EMERGENCY OPERATION switch?

No

Yes

Measure the resistance of the vane motor coil.

Refer to 10-5.

Turn OFF the power supply.

Check both “parts side” and “pattern side” of the indoor power P.C. board visually.

Replace the varistor (NR11) and fuse (F11). 3

Yes

Is the varistor (NR11) burnt and the fuse (F11) blown?

No

Be sure to check both the fuse and the varistor in any case.

Is the fuse (F11) blown only?

Yes

No

1. The fan motor connector's lead wire is red, whereas is black.

2. Connect "+" of the tester to fan motor connector's lead wire, and “-” to lead wire, otherwise the resistance cannot be measured properly.

3. Please replace the fuse after removing the indoor terminal P.C. board from the electrical box.

Measure the resistance between

CN211 (+) and (-) of indoor fan motor connector. 1, 2

Is the resistance 1M

Yes

Ω or more?

No

Short circuit:

Replace the vane motor and the indoor electronic control P.C. board.

With a tester, check the continuity between the connector CN201 on the indoor control P.C. board and

S2 on the terminal block.

Replace the fuse (F11) and the indoor fan motor. 3

Is electricity conducted? (The resistance is 0 Ω .)

No

The temperature fuse connected to the terminal block has failed.

Yes

Replace the terminal block assembly.

Replace the fuse (F11). 3

Measure the resistance of resistor

(R111) on the indoor power P.C. board.

Indoor electronic control

P.C. board

12 VDC 5 VDC

Indoor power P.C. board

GND

CN10A

Is the resistance of resistor (R111) approximately 4 Ω ?

No

Replace the indoor power P.C. board, the indoor terminal P.C. board and the indoor fan motor.

Yes

Is the approximately 5 VDC between

5 V (+) and GND (-) of the indoor electronic control P.C. board? Is there approximately 9 V to 13 VDC between

12 V (+) and GND (-) of the indoor electronic control P.C. board?

No

Yes

Replace the indoor fan motor.

Is the connector CN10A on the indoor electronic control

P.C. board or lead wires disconnected?

No

Yes

Connect the connector or repair disconnection.

Replace the indoor electronic control P.C. board.

R111

CN211

OBH647A 23

D How to check miswiring and serial signal error

Turn OFF the power supply.

Is there rated voltage in the power supply?

No

Yes

1. Turn ON the power supply.

2. Press the emergency operation switch.

Check the power supply.

No

Initializing the determination of the power receiving system

The microprocessor may have mistaken the unit as a model receiving power from the outdoor unit. Follow the procedure below to start the determination of the power receiving system all over again.

1. Hold down the emergency operation switch for 30 seconds. (Do not release the switch even though a buzzer beeps once in about 5 seconds. Keep holding down the switch until a buzzer beeps again for

1 second after 30 seconds. Figure 1)

2. Turn off the power supply.

3. Wait for about 30 seconds.

4. Turn on the power supply.

5. Press the emergency operation switch.

6. The relay 52C will be turned on in 3 minutes.

Has the relay 52C been turned on 3 minuets later ?

[The relay will be turned on in 3 to 7 seconds by short circuiting the timer short mode point (Refer to 10-7.).]

Yes

Has the miswiring or the serial error been indicated?

Yes

No

Indication of miswiring

Indication of serial signal error

OPERATION

INDICATOR lamp

Continuous blinks

Is there any miswiring, poor contact, or wire disconnection of the indoor/outdoor connecting wire?

Yes

No

Correct them.

A

Figure 1

Buzzer

ON

0.5-second

OFF

Beeps Beeps

Emergency operation switch

ON

OFF

5-second

1-second

Beeps

B

Turn OFF the power supply. Make sure again that the indoor/outdoor connecting wire is correctly connected. With the indoor/outdoor connecting wire connected, short circuit between S2 and S3 on the outdoor terminal block. 1

<Preparation of the remote controller>

While pressing both OPERATION SELECT button and

TOO COOL button on the remote controller at the same time, press RESET button.

First, release RESET button.

Hold down the other two buttons for another 3 seconds.

Make sure that the indicators on the LCD screen shown in the right fi gure are all displayed. Then release the buttons.

(Setting up the failure mode recall function)

ON

30-second

A

Turn OFF inverter-controlled lighting equipment.

Turn OFF the power supply and then turn ON again.

Press the emergency operation switch.

After the relay

52C is turned on

3 minutes later, is miswiring or the serial signal error indicated?

Yes

B

No

Reinstall either the unit or the light away from each other.

Attach a fi lter on remote control receiving section of the indoor unit.

OBH647A

OFF

Aim the remote controller at the indoor unit, and press

OPERATE/STOP (ON/OFF) button. The relay 52C will be turned on, and the outdoor unit will be energized.

1 Make sure that the wiring is correct. If the procedure is performed without correcting miswiring, it may lead to damage to the P.C. board.

Is the rated supply voltage applied between the S1 and S2 on the outdoor terminal block? (Check of supply voltage)

Yes

No

Is there any problem in the indoor/outdoor connecting wire, such as the damage of the wire, intermediate connection, poor contact with the terminal block?

No

Is there approximately 250 VDC – 370

VDC between DB61 (+) and DB61

(–) on the inverter P.C. board in the outdoor unit? (Voltage check of the inverter P.C. board in the outdoor unit)

No

Replace the inverter P.C. board in the outdoor unit. 2

Yes

2 Be careful of 140

VDC – 280 VDC residual charge in the capacitor on the main inverter circuit.

Does the LED on the inverter P.C. board in the outdoor unit repeat

"3.6-second-OFF and 0.8-second-

ON quick blinking" for 3 minutes after the outdoor unit is energized?

(Check the blinking pattern within 3 minutes after LED is turned on. After 3 minutes, LED will blink 6 times whether the inverter P.C. board in the outdoor unit is normal or not.)

Yes

No

Replace the inverter P.C. board in the outdoor unit. 2

Replace the indoor electronic control

P.C. board. 3

3 Be sure to release the failure-mode recall function after checking.

24

Yes

Replace the indoor/ outdoor connecting wire.

E Electromagnetic noise enters into TV sets or radios

Is the unit earthed?

Yes

No

Earth the unit.

Is the distance between the antennas and the indoor unit within 3 m, or is the distance between the antennas and the outdoor unit within 3 m?

No

Yes

Is the distance between the TV sets or radios and the indoor unit within 1 m, or is the distance between the TV sets or radios and the outdoor unit within 3 m?

No

Yes

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.

Are the antennas damaged?

Is the coaxial cable damaged?

Is there any poor contact in the antenna wiring?

No

Yes

Is the indoor/outdoor connecting wire of the air conditioner and the wiring of the antennas close?

No

Yes

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, earth 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 OPERATE/STOP (ON/OFF) 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 OPERATE/STOP (ON/OFF) 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.

OBH647A 25

10-7. TEST POINT DIAGRAM AND VOLTAGE

1. Indoor power P.C. board

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

Fuse (F11)

T3.15AL250V

Connector to

Terminal block

(CN201)

Varistor (NR11) Resistor (R111)

Connector to

Indoor fan motor

(CN211)

(+)0 or 15 VDC

(+)3-6 VDC

15 VDC

(-) GND

(High voltage DC)

325 VDC

Indoor terminal block connecting (TAB1)

12 VDC GND 5 VDC

Connector to indoor electronic control P.C. board (CN20A)

Indoor terminal block connecting (TAB2)

2. Indoor electronic control P.C. board

Room temperature thermistor RT11 (CN111)

To disable "Auto restart function", cut the Jumper wire to JR77.

(Refer to 8-3.)

Vane motor

(CN151)

5V DC

Emergency operation switch (E.O. SW) (SW1)

12V DC

OBH647A

Connector to indoor power

P.C. board (CN10A)

26

Connector to

Indoor coil thermistor

RT12, RT13

(CN112)

Timer short mode point

(Refer to

8-1.)

GND

Room temperature thermistor (RT11)

Indoor coil thermistor (RT12, RT13)

Temperature (°C)

11 DISASSEMBLY INSTRUCTIONS

<"Terminal with locking mechanism" Detaching points>

The terminal which has the locking mechanism can be detached as shown below.

There are two types (refer to (1) and (2)) of the terminal with locking mechanism.

The terminal without locking mechanism can be detached by pulling it out.

Check the shape of the terminal before detaching.

(1) Slide the sleeve and check if there is a locking lever or not.

(2) The terminal with this connector has the

locking mechanism.

Sleeve

Locking lever

Slide the sleeve.

Pull the terminal while pushing the locking lever.

Hold the sleeve, and pull out the terminal slowly.

Connector

MSZ-HJ25VA MSZ-HJ35VA MSZ-HJ50VA

OPERATING PROCEDURE

1. Removing the panel

(1) Remove the screw caps on the panel and remove the screws of the panel.

(2) Pull the panel slightly toward you, and then remove the panel by pushing it upward.

NOTE: Turn OFF power supply before disassembly.

PHOTOS

Photo 1

Front panel

Horizontal vane

Screws of the panel

OBH647A 27

OPERATING PROCEDURE

2. Removing the indoor power P.C. board and the electrical box

(1) Remove the panel. (Refer to 1.) Remove the right corner box.

(2) Disconnect the following connectors:

<Indoor electronic control P.C. board>

CN151 (Vane motor)

CN112 (Indoor coil thermistor)

CN10A (To the indoor power P.C. board)

(3) Unhook the catch on the left side of the control P.C. board holder. Pull the control P.C. board holder as if opening the door at 90 degrees. Remove the control P.C. board holder from the axial rod on the electrical box.

(4) Remove the screw of the V.A. clamp.

(5) Remove the V.A. clamp and the indoor/outdoor connecting wire.

(6) Remove the earth wire connected to the indoor heat exchanger from the electrical box.

(7) Remove the screw of the electrical cover and remove the electrical cover.

(8) Disconnect the following connectors:

<Indoor power P.C. board>

CN211 (Indoor fan motor)

CN201 (Terminal block)

CN20A (To the indoor electronic control P.C. board)

Photo 2

Indoor electronic control

P.C. board

Photo 3

PHOTOS

Earth wire

Screw of the electrical cover

Screw of the

V.A. clamp

Vane motor connector CN151

Indoor coil thermistor connector CN112

Connector CN10A

(To indoor power

P.C. board)

Control P.C. board holder

Electrical box

(9) Remove the upper catch of the electrical box, and pull out the electrical box.

To attach the electrical box, pass the wires connecting the indoor power P.C. board and the indoor electronic control P.C. board through A. Pass the lead wires of the fan motor through B as shown in the Photo 3.

Terminal block connector CN201

Indoor fan motor connector CN211

Connector CN20A

(To indoor electronic P.C. board)

Power P.C. board

OBH647A 28

OPERATING PROCEDURE

3. Removing the indoor electronic control P.C. board

(1) Remove the panel. (Refer to 1.) Remove the right corner box.

(2) Disconnect the following connectors:

<Indoor electronic control P.C. board>

CN151 (Vane motor)

CN112 (Indoor coil thermistor)

CN10A (To the indoor power P.C. board)

(3) Unhook the catch on the left side of the control P.C. board holder. Pull the control P.C. board holder as if opening the door at 90 degrees. Remove the control P.C. board holder from the axial rod on the electrical box.

(4) Remove the room temperature thermistor from the back side of the control P.C. board holder.

(5) Unhook the catches of the control P.C. board holder, and open the control P.C. board holder.

(6) Remove the indoor electronic control P.C. board from the control P.C. board holder.

PHOTOS

Photo 4

Control P.C. board holder (Inside)

Catch

Indoor electronic control P.C. board

Catch

Control P.C. board holder (Back side)

Room temperature thermistor

4. Removing the vane motor

(1) Remove the panel. (Refer to 1.) Remove the right corner box.

(2) Remove the control P.C. board holder and the electrical box. (Refer to 2.)

(3) Pull out the drain hose from the nozzle assembly and remove the nozzle assembly.

(4) Remove the screws of the vane motor and remove the vane motor.

(5) Disconnect the connector from the vane motor.

Photo 5

Screws of the vane motor

OBH647A

OPERATING PROCEDURE

5. Removing the indoor fan motor, the indoor coil thermistor and the line flow fan

(1) Remove the panel. (Refer to 1.) Remove the right corner box.

(2) Remove the control P.C. board holder, the electrical box and the nozzle assembly. (Refer to 2.)

(3) Remove the screws fixing the motor bed.

(4) Disengage the hooks of the water cover and remove the water cover.

(5) Disconnect the earth wire from the motor band.

(6) Remove the indoor coil thermistor from the motor band.

(7) Loosen the screw fixing the line flow fan.

(8) Remove the motor bed together with the indoor fan motor and the motor band.

(9) Disconnect the lead wire of the fan motor from the motor band.

(10) Disengage the hooks of the motor band and remove the motor band. Pull out the indoor fan motor.

(11) Remove the indoor coil thermistor from the heat exchanger.

Install the indoor coil thermistor in its former position when assembling it.

(12) Remove the screws fixing the left side of the heat exchanger.

(13) Lift the heat exchanger, and pull out the line flow fan to the lower-left.

When attaching the line flow fan, screw the line flow fan so 4 mm gap is provided between the right end of the line flow fan and the right wall of the air passage of the box (Figure 1).

Figure 1

Photo 6

Photo 7

PHOTOS

Screws of the line flow fan

Earth wire

Motor band

Indoor coil thermistor

4 mm

Water cover

Photo 8

Screws of the motor bed

Photo: MSZ-HJ50VA

Screws of the left side of the heat exchanger

OBH647A 30

Fixing the indoor coil thermisor

There are 2 forms of parts for fixing the indoor coil thermistor.

Clip shape Holder shape

Position and procedure for mounting the clip-shape part

1. Set the indoor coil thermistor in the center of the clip-shape part.

2. Check the (marked) mounting position.

About the same length

3.Mount the

NOTE:

Take care to avoid loss and accidental falling of the clip-shape part inside the unit.

Mount the clip-shape part on the marked position.

Do not pull the lead wire when removing the indoor coil thermistor.

OBH647A 31

HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN

© Copyright 2012 MITSUBISHI ELECTRIC CORPORATION

Distributed in Mar. 2013. No. OBH647 REVISED EDITION-A

Distributed in Dec. 2012. No. OBH647

Made in Japan

New publication, effective Mar. 2013

Specifications are subject to change without notice.

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Key Features

  • Cooling & heating
  • Microprocessor control
  • Timer operation
  • Auto restart function
  • Emergency operation
  • Multiple fan speeds
  • Auto vane operation

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Frequently Answers and Questions

What are the models covered in this service manual?
The service manual covers the MSZ-HJ25VA, MSZ-HJ35VA, and MSZ-HJ50VA models.
What are the contents of the service manual?
The service manual contains information about technical changes, part names and functions, specifications, noise criteria curves, outlines and dimensions, wiring diagram, refrigerant system diagram, service functions, microprocessor control, troubleshooting, and disassembly instructions.
How do I operate the air conditioner in emergency mode?
To operate the air conditioner in emergency mode, press the EMERGENCY OPERATION switch on the right side of the indoor unit. The unit will start, and the OPERATION INDICATOR lamp will light. The first 30 minutes of operation is the test run operation. This operation is for servicing. After 30 minutes of test run operation, the system shifts to EMERGENCY COOL/HEAT MODE with a set temperature of 24°C.
What is the purpose of the 3-minute time delay operation?
The 3-minute time delay operation protects the compressor from overload. When the system turns OFF, the compressor will not restart for 3 minutes.
How do I replace the batteries in the remote controller?
To replace the batteries in the remote controller, press the RESET button with a thin instrument and remove the back lid. Insert the batteries, ensuring the polarity is correct. Then reattach the back lid.
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