Mitsubishi OBH488C Service Manual

SPLIT-TYPE AIR CONDITIONERS

INDOOR UNIT

SERVICE MANUAL

Models

Revision C:

• MSZ-FD•VA(S)- E2 has been added.

Please void OBH488 REVISED EDITION-B.

No. OBH488

REVISED EDITION-C

MSZ-FD25VA -

E1,E2

MSZ-FD25VAS ­MSZ-FD35VA -

E1,E2

MSZ-FD35VAS ­MSZ-FD50VA -

E1,E2

MSZ-FD50VAS -

E1,E2

E1,E2

E1,E2

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 ······································ 20

11. DISASSEMBLY INSTRUCTIONS ·····················36

Outdoor unit service manual
MUZ-FD·VA(H) Series (OBH489)
MUZ-FD·VABH Series (OBH519)
MXZ-A·VA Series (OB377)
MXZ-8A140A (OC316)

NOTE:

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

PARTS CATALOG (OBB488)

Revision A:

• 3. SPECIFICATION has been corrected.

• 10-5. TROUBLE CRITERION OF MAIN PARTS has been corrected.

Revision B:

• MSZ-FD50VA(S)- E1 has been added.

Revision C:

• MSZ-FD•VA(S)- E2 has been added.

2

1

TECHNICAL CHANGES

MSZ-FD25VA ­MSZ-FD35VA ­MSZ-FD50VA -

1. New model

MSZ-FD25VA(S) ­MSZ-FD35VA(S) ­MSZ-FD50VA(S) -

1. Remote controller has been changed. (KM08A → KM09D)

E1

MSZ-FD25VAS -

E1

MSZ-FD35VAS -

E1

MSZ-FD50VAS -

E1

→ MSZ-FD25VA(S) -

E1

→ MSZ-FD35VA(S) -

E1

→ MSZ-FD50VA(S) -

E1

E1

E1

E2

E2

E2

3

2

PART NAMES AND FUNCTIONS

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS

AREA lamp

Operation Indicator
lamp

Front panel

Air filter

Air inlet

Plasma deodorizing filter

Plasma electrode unit

Plasma anti-allergy
enzyme filter

Air outlet

Fan guard

Fan

Horizontal vane

POWER lamp

Heat exchanger

Vertical vane

CLEAN lamp

i-see Sensor

PLASMA lamp

Remote control
receiving section

Emergency operation switch

Remote controller

ACCESSORIES

AREA lamp indicates AREA setting

In AREA setting, the horizontal air fl ow
direction changes automatically according to
the detection of i-see Sensor which detects
the fl oor/wall temperature to air-condition the
room evenly.

Installation plate 1
Installation plate fi xing screw 4 × 25 mm 5
Remote controller holder 1
Fixing screw for 3.5 × 1.6 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (Used for left or left-rear piping) 1

i-see control operation

i-see Sensor constantly measure
fl oor/wall temperature to automatically
adjust to the set temperature by
estimating the temperature actually
perceived by a person inside the room
(“sensible temperature”).

4

3

SPECIFICATION

Indoor model

Power supply

Power input 1

Running current 1

Electrical

data

Model RC0J40-GF

Fan motor

Dimensions W×H×D mm 798 × 295 × 257
Weight kg 12

Color

Air direction 4

Airfl ow

Sound level

Special remarks

Fan speed

Fan speed regulator 4

Remote controller model

NOTE: Test conditions are based on ISO 5151.
Cooling: Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C
Outdoor Dry-bulb temperature 35°C
Heating: Indoor Dry-bulb temperature 20°C
Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C
1 Measured under rated operating frequency.

Current 1

Cooling

Heating

Cooling

Heating

Cooling

Heating

Cooling
Heating 31 33
Cooling
Heating 0.30 0.32

Cooling
Heating 0.30 0.32

Super High
High 516 672
Med 378 534
Low 276 378
Super High 726 750 888
High 552
Med 402 534
Low 270 282 330
Super High
High 36 45
Med 29 39
Low 20
Super High 43 44 50
High 36 43
Med 29 37
Low 20 21 27
Super High
High 950 1,200
Med 740 1,000
Low 580 760
Super High 1,270 1,300 1,500
High 1,010
Med 780
Low 570 590

W

A

A

3

m

/h

dB(A)

rpm

MSZ-FD25VA

MSZ-FD25VAS

26 28

0.25 0.27

0.25 0.27

FD25VA

PURE WHITE

FD25VAS

SILVER

672 888

42 43 52

1,190 1,500

MSZ-FD35VA

MSZ-FD35VAS

Single phase
230 V, 50 Hz

FD35VA

PURE WHITE

FD35VAS

SILVER

21

E1

: KM08A / E2: KM09D

MSZ-FD50VA

MSZ-FD50VAS

60

0.53

0.53

FD50VA

PURE WHITE

FD50VAS

SILVER

672

29

1,200
1,000

680

Specifi cations and rating conditions of main electric parts

Fuse (F11) 250 V 3.15 A
i-see Sensor motor (MT) MP20Z 12 VDC 300 Ω (at 25°C)
Horizontal vane motor (MV1) MSFBC20C29 12 VDC 350 Ω (at 25°C)
Vertical vane motor (MV2) MSBPC20M11 12 VDC 300 Ω (at 25°C)
Varistor (NR11) S10K320E3K1
i-see Sensor (RR) A2TPMI 23A FOV50 OBA060 P8L1 J4S
Terminal block (TB) 3P

5

4

NOISE CRITERIA CURVES

MSZ-FD25VA MSZ-FD25VAS

FAN SPEED

Super High

90

80

70

60

50

40

30

20

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

10

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

FUNCTION

COOLING

HEATING

SPL(dB(A))

42
43

NC-10

LINE

NC-70

NC-60

NC-50

NC-40

NC-30

NC-20

MSZ-FD35VA MSZ-FD35VAS

FAN SPEED

Super High

90

80

70

60

50

40

30

20

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

10

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

FUNCTION

COOLING

HEATING

SPL(dB(A))

43
44

NC-10

LINE

NC-70

NC-60

NC-50

NC-40

NC-30

NC-20

MSZ-FD50VA MSZ-FD50VAS

FAN SPEED

Super High

90

80

70

60

50

40

30

FUNCTION

COOLING

HEATING

SPL(dB(A))

52
50

Test conditions
Cooling : Dry-bulb temperature 27 Wet-bulb temperature 19

Heating : Dry-bulb temperature 20 Wet-bulb temperature 15.5

LINE

INDOOR UNIT

WALL

1 m

0.8 m

MICROPHONE

NC-70

NC-60

NC-50

NC-40

NC-30

20

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

10

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

NC-10

NC-20

6

5

OUTLINES AND DIMENSIONS

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS
MSZ-FD50VA MSZ-FD50VAS

11 X 26 Oblong hole

254

7

100

Air out

64

212.5

41

54

Air in

Insulation ø35 O.D
Liquid line ø7 - 0.5 m (Flared connection ø6.35)

Piping

Gas line

Drain hose Insulation ø28 O.D Connected part ø16 O.D

Installation plate

798
785

69

43

295

55 55688

58

159

19

6.5

47

Indoor unit

11 X 20 Oblong hole

225 225

155155

345

Installation plate

5257

Piping

56

43
85
97

330 69

Drain hose

25/35: ø9.52 - 0.43 m (Flared connection ø9.52)
50: ø9.52 - 0.43 m (Flared connection ø12.7)

64

211.5

Wall hole ø65

Unit: mm

21.5

253

231.5

3

42

6

WIRING DIAGRAM

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS

7

7

REFRIGERANT SYSTEM DIAGRAM

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS

Refrigerant pipe ø9.52
(with heat insulator)

Unit: mm

MSZ-FD50VA MSZ-FD50VAS

Indoor
heat
exchanger

Indoor coil
thermistor
RT13 (sub)

Room temperature
thermistor
RT11

Indoor coil
thermistor
RT12 (main)

Flared connection

Flared connection

Refrigerant pipe ø6.35
(with heat insulator)

Refrigerant flow in cooling
Refrigerant flow in heating

Indoor
heat
exchanger
(Main)

Indoor heat
exchanger
(Sub)

Room
temperature
thermistor
RT11

Indoor coil
thermistor
RT12 (main)

Indoor coil
thermistor
RT13 (sub)

Refrigerant pipe ø12.7
(with heat insulator)

Flared connection

Flared connection

Refrigerant pipe ø6.35
(with heat insulator)

Refrigerant flow in cooling
Refrigerant flow in heating

8

8

SERVICE FUNCTIONS

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS

8-1. TIMER SHORT MODE

For service, set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board.
The time will be shortened as follows. (Refer to 10-7.)
Set time: 1-minute → 1-second
Set time: 3-minute → 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is

shortened by short circuit-of JPG and JPS.)

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:

NOTE: For modification, take out

the batteries and press
the OPERATE/STOP (ON/
OFF) button twice or 3
times at first.

After modification, put back

the batteries then press the

J1

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.

J2

RESET button.

Table 1

1 unit operation 2 units operation 3 units operation 4 units operation

No. 1 unit No modifi cation 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 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 restored.

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 release “AUTO RESTART FUNCTION”

Turn OFF the main power for the unit.
Solder the Jumper wire JR07 on the indoor electronic control

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

CN130

IC156

JR07

CN1U1

NOTE:

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

controller.

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

celled.

• If the unit has been OFF with the remote controller before power failure, the auto restart function does not work as the

power button of the remote controller is OFF.

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

same time.

• When some air conditioners are connected to the same supply system, if they are operated before power failure, the

starting current of all the compressors may flow simultaneously at restart.

Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current

by adding to the system that allows the units to start one by one.

8-4. REMOTE CONTROLLER

Be sure to set the slide switch inside the remote controller to an appropriate position in accordance with the installed
position of the indoor unit. If the switch is not set correctly, the air conditioner may not function properly.

CN212

CN1T1

CN151 CN211CN112 CN1R1

Slide switch

Where is the indoor unit installed in your room?

Installed at left, if the
distance is not more
than 50 cm.

(Left) (Center) (Right)

NOTE:If the indoor unit is installed more than 50 cm away from the side walls, cabinets or other nearby objects, set the slide

switch to the “center” position.

Installed at right, if the
distance is not more
than 50 cm.

Area Left Center Right

Position of

the slide

switch

Display on

the remote

controller

Is the indoor unit
installed at right,
left or center?

10

9

MICROPROCESSOR CONTROL

MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Operation display section

OPERATE/STOP
(ON/OFF) button

Temperature buttons

FAN SPEED CONTROL button

OPERATION SELECT button

ECONO COOL button

PLASMA button

CLEAN button

i-see button
AREA button
RESET button

Indication of
remote controller
model is on back

VANE CONTROL button

OFF TIMER button

ON TIMER button

TIME SET buttons
FORWARD button
BACKWARD button

WIDE VANE button

(Vertical vane button)

CLOCK SET 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 LAMP

The lamps at the center of the indoor unit indicates the operation state.

Lamp Operation state

AREA Refer to 9-7.

POWER

CLEAN

PLASMA

Lamp lights during operation.
Lamp blinks in abnormal condition.

Lamp lights during clean operation.
Refer to 9-9.

Lamp lights during PLASMA operation.
Refer to 9-8.

11

9-1. COOL ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) button.
POWER 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.

2. Low outside temperature operation

When the outside temperature is lower, low outside temperature operation starts, and the outdoor fan slows or stops.

9-2. DRY ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) button.
POWER 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.)

2. Low outside temperature operation

Low outside temperature operation is as same as COOL mode. (9-1.2.)

9-3. HEAT ( ) OPERATION

(1) Press OPERATE/STOP (ON/OFF) button.
POWER 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 CHANGE OVER ··· AUTO MODE OPERATION

Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.

Mode selection

(1) Initial mode
When unit starts the operation with AUTO operation from OFF:

• If the room temperature is higher than the set temperature, operation starts in COOL mode.

• If the room temperature is equal to or lower than the set temperature, operation starts in HEAT mode.

(2) Mode change
COOL mode changes to HEAT mode when about 15 minutes have passed with the room temperature 1°C below the set

temperature.

HEAT mode changes to COOL mode when about 15 minutes have passed with the room temperature 1°C above the set

temperature.

NOTE 1

If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is operating in

(AUTO), cannot change over to the other operating mode (COOL HEAT) and becomes a state of standby.

Refer to NOTE 2 “FOR MULTI SYSTEM AIR CONDITIONER”.

12