Mitsubishi Electric MSZ-FD25VA User manual

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
SPLIT-TYPE AIR CONDITIONERS
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
Outdoor unit service manual
MUZ-FD·VA(H) Series (OBH489)
MUZ-FD·VABH Series (OBH519)
MXZ-A·VA Series (OB377)
MXZ-8A140A (OC316)
SERVICE MANUAL
Models
No. OBH488
REVISED EDITION-C
INDOOR UNIT
PARTS CATALOG (OBB488)
Revision C:
• MSZ-FD•VA(S)- E2 has been added.
Please void OBH488 REVISED EDITION-B.
MSZ-FD25VA - E1 ,E2
MSZ-FD25VAS - E1 ,E2
MSZ-FD35VA - E1 ,E2
MSZ-FD35VAS - E1 ,E2
MSZ-FD50VA - E1 ,E2
MSZ-FD50VAS - E1 ,E2

2
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.

3
MSZ-FD25VA - E1 MSZ-FD25VAS - E1
MSZ-FD35VA - E1 MSZ-FD35VAS - E1
MSZ-FD50VA - E1 MSZ-FD50VAS - E1
1. New model
TECHNICAL CHANGES
1
MSZ-FD25VA(S) - E1 →MSZ-FD25VA(S) - E2
MSZ-FD35VA(S) - E1 →MSZ-FD35VA(S) - E2
MSZ-FD50VA(S) - E1 →MSZ-FD50VA(S) - E2
1. Remote controller has been changed. (KM08A →KM09D)

4
ACCESSORIES
Installation plate 1
Installation plate fixing 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
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS
Fan
Fan guard
i-see Sensor
Air inlet
Air filter
Plasma deodorizing filter
Plasma electrode unit
Plasma anti-allergy
enzyme filter
Air outlet
Horizontal vane Vertical vane
Heat exchanger
Emergency operation switch
Remote controller
Remote control
receiving section
AREA lamp POWER lamp CLEAN lamp PLASMA lamp
Operation Indicator
lamp
Front panel
AREA lamp indicates AREA setting
In AREA setting, the horizontal air flow
direction changes automatically according to
the detection of i-see Sensor which detects
the floor/wall temperature to air-condition the
room evenly.
i-see control operation
i-see Sensor constantly measure
floor/wall temperature to automatically
adjust to the set temperature by
estimating the temperature actually
perceived by a person inside the room
(“sensible temperature”).
PART NAMES AND FUNCTIONS
2

5
Indoor model MSZ-FD25VA
MSZ-FD25VAS
MSZ-FD35VA
MSZ-FD35VAS
MSZ-FD50VA
MSZ-FD50VAS
Power supply Single phase
230 V, 50 Hz
Electrical data
Power input 1 Cooling W26 28 60
Heating 31 33
Running current 1 Cooling A0.25 0.27 0.53
Heating 0.30 0.32
Fan motor
Model RC0J40-GF
Current 1 Cooling A0.25 0.27 0.53
Heating 0.30 0.32
Dimensions W×H×D mm 798 × 295 × 257
Weight kg 12
Color
FD25VA
PURE WHITE
FD35VA
PURE WHITE
FD50VA
PURE WHITE
FD25VAS
SILVER
FD35VAS
SILVER
FD50VAS
SILVER
Special remarks
Air direction 4
Airflow
Cooling
Super High
m3/h
672 888
High 516 672
Med 378 534
Low 276 378
Heating
Super High 726 750 888
High 552 672
Med 402 534
Low 270 282 330
Sound level
Cooling
Super High
dB(A)
42 43 52
High 36 45
Med 29 39
Low 20 21 29
Heating
Super High 43 44 50
High 36 43
Med 29 37
Low 20 21 27
Fan speed
Cooling
Super High
rpm
1,190 1,500
High 950 1,200
Med 740 1,000
Low 580 760
Heating
Super High 1,270 1,300 1,500
High 1,010 1,200
Med 780 1,000
Low 570 590 680
Fan speed regulator 4
Remote controller model E1 : KM08A / E2 : KM09D
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.
Specifications 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
SPECIFICATION
3

6
MSZ-FD25VA MSZ-FD25VAS
INDOOR UNIT WALL
MICROPHONE
0.8 m
1 m
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
Super High
FAN SPEED
HEATING
Test conditions
Cooling : Dry-bulb temperature 27 Wet-bulb temperature 19
Heating : Dry-bulb temperature 20 Wet-bulb temperature 15.5
43
44
NC-10
MSZ-FD35VA MSZ-FD35VAS
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
Super High
FAN SPEED
HEATING
42
43
NC-10
MSZ-FD50VA MSZ-FD50VAS
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
Super High
FAN SPEED
HEATING
52
50
NC-10

7
225 225 64
64
155155
345
54 330 69
42
211.5
3
253
231.5
41 212.5
254
43
69
7
43
85
97
295
21.5
56
55 55688
100
785
798 6.5
47
Wall hole ø65
11 X26 Oblong hole 11 X20 Oblong hole
Indoor unit
Installation plate
5257 Installation plate
Piping
Drain hose
Air in
Air out
19
159
58
Unit: mm
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS
Piping
Insulation ø35 O.D
Liquid line ø7 - 0.5 m (Flared connection ø6.35)
Gas line 25/35: ø9.52 - 0.43 m (Flared connection ø9.52)
50: ø9.52 - 0.43 m (Flared connection ø12.7)
Drain hose Insulation ø28 O.D Connected part ø16 O.D
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS
MSZ-FD50VA MSZ-FD50VAS
OUTLINES AND DIMENSIONS
5
WIRING DIAGRAM
6

8
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
Indoor coil
thermistor
RT12 (main)
Indoor coil
thermistor
RT13 (sub)
Refrigerant flow in cooling
Refrigerant flow in heating
Unit: mm
MSZ-FD50VA MSZ-FD50VAS
Indoor
heat
exchanger
(Main)
Flared connection
Room
temperature
thermistor
RT11 Flared connection
Refrigerant pipe ø12.7
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
Indoor coil
thermistor
RT12 (main)
Indoor coil
thermistor
RT13 (sub)
Refrigerant flow in cooling
Refrigerant flow in heating
Indoor heat
exchanger
(Sub)
REFRIGERANT SYSTEM DIAGRAM
7

9
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:
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.
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
RESET button.
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS
J2
J1
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 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.
SERVICE FUNCTIONS
8

10
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.
8-3. 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.)
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.
Area Left Center Right
Where is the indoor unit installed in your room?
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.
(Left) (Center) (Right)
Slide switch
Position of
the slide
switch
Display on
the remote
controller
Installed at left, if the
distance is not more
than 50 cm.
Installed at right, if the
distance is not more
than 50 cm.
Is the indoor unit
installed at right,
left or center?
JR07
CN151 CN211CN112 CN1R1
CN212
CN1T1
CN1U1
CN130
IC156

11
ON TIMER button
CLOCK SET button
TIME SET buttons
FORWARD button
BACKWARD button
OFF TIMER button
RESET button
VANE CONTROL button
WIDE VANE button
(Vertical vane button)
CLEAN button
AREA button
i-see button
Signal transmitting section
Operation display section
OPERATE/STOP
(ON/OFF) button FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button
Indication of
remote controller
model is on back
PLASMA button
Temperature buttons
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
WIRELESS REMOTE CONTROLLER
INDOOR UNIT LAMP
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS
The lamps at the center of the indoor unit indicates the operation state.
Lamp Operation state
AREA Refer to 9-7.
POWER Lamp lights during operation.
Lamp blinks in abnormal condition.
CLEAN Lamp lights during clean operation.
Refer to 9-9.
PLASMA Lamp lights during PLASMA operation.
Refer to 9-8.
MICROPROCESSOR CONTROL
9

12
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 tem-
perature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.
2. High pressure protection
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the con-
densing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
The indoor fan operates following the cold air prevention control. This mode continues until the temperature of indoor heat
exchanger falls.
3. Defrosting
Defrosting starts when the temperature of outdoor heat exchanger becomes too low.
The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.
This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.
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”.

13
9-5. 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 (approx. 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.
Confirming of standard position is performed in the following cases:
(a) The operation starts or finishes (including timer operation).
(b) The test run operation starts.
(c) Standby mode (only during multi system operation) starts or finishes.
(4) VANE AUTO ( ) mode
The microprocessor automatically determines the vane angle to make the optimum room temperature distribution.
(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 or 30 minutes, the vane angle automatically changes to Angle 2 for dew prevention.
NOTE 2
FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and
the others for heating, the operation mode of the indoor unit that operates first is selected. Other indoor units
cannot operate, and operation indicator lamp flashes as shown in the figure below. In this case, please set all the
indoor units to the same operation mode.
•When indoor unit starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes (max.
10 minutes) to blow out the warm air.
•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flow-
ing may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
1
COOL and DRY operation
Vane angle is fixed to Angle 1.
HEAT operation
Vane angle is fixed to Angle 4.
L AREA R POWER CLEAN PLASMA
Lighted
Blinking
Not lighted
AUTO →1 →2 →3 →4 →5 →SWING

14
(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) To change the airflow direction not to blow directly onto your body.
To change the airflow direc-
tion When to use this function? COOL/DRY HEAT
Pressing and holding
VANE CONTROL button
for 2 seconds or more, the
horizontal vane reverses
and moves horizontal
position.
Use this function if you do
not want the air from the
indoor unit to blow directly
onto your body.
• Depending on the shape
of the room, the air may
blow directly onto your
body.
• Press VANE CONTROL
button again to return the
vane to the previously-
set position.
The air conditioner starts
the cooling or drying op-
eration approx. 3 minutes
after the vane has moved
to the horizontal position.
• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the cool or dry
operation in approx. 3
minutes.
The air conditioner starts
heating operation approx.
3 minutes after the vane
has moved to the horizon-
tal position.
• Sometimes the area
around your feet may not
get warm. To warm the
area around the feet, set
the horizontal vane to
(AUTO) or the down-
ward-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 approx. 3 minutes.
NOTE:
• If you make the airflow 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 conditioner 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 changed to other operation mode.
2. Vertical vane
(1) Vane motor drive
These models are equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of the
motor are controlled by pulse signals (approx. 12 V) transmitted from microprocessor.
(2) The vertical vane angle and mode change as follows by pressing WIDE VANE 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.
Confirming of standard position is performed in the following cases:
(a) OPERATE/STOP (ON/OFF) button is pressed (POWER ON).
(b) SWING is started.
(4) SWING ( ) MODE
By selecting SWING mode with WIDE VANE button, the vertical vane swings horizontally. The remote controller displays
“ ”. Swing mode is cancelled when WIDE MODE button is pressed once again.
Horizontal
position
(SWING)
123 45

15
9-6. i-see CONTROL OPERATION
The sensors constantly measure the room and floor/wall temperatures to automatically adjust to the set temperature by esti-
mating the temperature actually perceived by a person inside the room (“sensible temperature”).
Advantages
· The air inside the room is conditioned quickly to a comfortable condition.
· The room will not become too cold or hot even when the air conditioner is kept on for a long period.
· The air conditioner will not overcool or overheat, which means you can save on electricity.
i-see control operation is activated when i-see button is pressed with a thin stick in manual COOL or manual HEAT mode.
NOTE: i-see control operation is activated when the remote controller is first used following replacement of the batteries
or resetting of the remote controller.
i-see control operation is cancelled when i-see button is pressed with a thin stick once again.
NOTE: If the conditioner is turned OFF without cancelling i-see control operation, i-see control operation is activated the
next time the air conditioner is turned ON.
i-see Sensor
i-see Sensor, which is installed on the upper of the air outlet of the indoor unit, is moved with the stepping motor and it
detects the floor/wall temperature.
i-see Sensor is installed here. Enlarged view of i-see Sensor
9-7. AREA ( ) SETTING
(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(2) Press i-see button. (NOTE 1)
(3) Press AREA button.
Each time the button is pressed, the area is changed in sequence:
(AUTO) (LEFT) (RIGHT) Cancel
i-see Sensor moves intermittently, measuring the floor and wall temperature.
(4) AREA setting is cancelled when the "cancel" is selected by pressing AREA button, or when WIDE VANE button is pressed.
NOTE 1: AREA setting is only available during i-see control operation.
NOTE 2: If AREA setting is cancelled, the vertical vane returns to the previously set position before AREA setting.
NOTE 3: The horizontal air flow direction (WIDE VANE button), including horizontal SWING, cannot be set during AREA
setting
i-see Sensor
• When AREA setting is not activated, the sensing range of i-see Sensor differs depending on the installation location of
the air conditioner.
Installation position Installed at left Installed at center Installed at right
Image of sensing
range
Direction of sensor Right Center Left
Refer to "Remote controller in SERVICE FUNCTIONS".
• Install the front panel correctly after being removed for maintenance or service so that the floor/wall temperatures can be
measured correctly

16
Indoor unit installation location and air-conditioning area
•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.
(Refer to "Remote controller in SERVICE FUNCTIONS".)
Installed at left Installed at center Installed at right
LEFT RIGHT LEFT RIGHT LEFT RIGHT
To air-condition mainly
the left area of the room To air-condition the entire room The horizontal air flow direction and in-
door unit display are switched accord-
ing to the room temperature (floor/wall).
To air-condition mainly
the right area of the room
Remote controller button PressAREAbutton
toselectLEFT. Press AREAbutton to select AUTO. Press AREA button
to select RIGHT.
i-see Sensor operation
Control range
of horizontal air
flow direction.
The vertical air
flow direction
conforms to the
setting on the
remote controller.
(The horizontal
air flow direction
is controlled in
this range.)
Installed
at center
Installed
at left
Installed
at right
Indoor unit
display AREA
Remotecontrollerdisplay
or or Lighted
Not lighted
L R L R L R L R L R
Ex.) In COOL mode
Moving of horizontal air flow direction
Indoor unit
display
NOTE
Indication of AREA setting Lighted
Not lighted
• The horizontal air flow direction changes if i-see Sensor detects approx. 3 °C temperature difference.
• InAUTO of AREAsetting, both right and left lamps are lighted when the room is evenly air-conditioned.
AREA RLAREA RL
AREA RL
The indoor unit delivers cold air detecting the warm area in the room.
Daytime Nighttime
Warm area Cold area
Approx. 150 degrees
When AREA is set to AUTO
• The vertical vane is controlled to maintain uniform temperature in the whole room.
• The i-see Sensor moves in a range of 150 degrees detecting floor/wall temperature of 3 areas
(left, right, center). Therefore, the detected temperatures may be different from the temperatures
measured on commercial thermometers depending on the condition or temperature
distribution on the floor and/or wall.

17
Operation and operating range
i-see sensor moves 30 degrees from the center in both right and left side.
i-see Sensor operates as follows in accordance with AREA setting made with the remote controller.
“AUTO” in AREA setting: first turning to the LEFT for adjusting the position then.....
CENTER RIGHT CENTER LEFT CENTER......
(The sensor turns to the right, left and center.)
“RIGHT” in AREA setting: first turning to the LEFT for adjusting the position then....
CENTER RIGHT CENTER RIGHT CENTER......
(The sensor turns to the right and center.)
“LEFT” in AREA setting: first turning to the LEFT for adjusting the position then....
CENTER LEFT CENTER LEFT CENTER......
(The sensor turns to the left and center.)
The sensor finishes turning to one area to another for 3 seconds and it operates one area for 5 seconds.
i-see Sensor turning to the right
i-see Sensor turning to the center
i-see Sensor turning to the left
Description of PLASMA operation:
Plasma operation consists of deodorizing and air purifying features.
Particles of odor-releasing substances are absorbed and decomposed by the plasma deodorizing filter.
Particles of allergens such as pollen and house dust are collected by the plasma anti-allergy filter.
These filters work with negative ions generated by the plasma electrode unit.
9-8. PLASMA ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(2) Press PLASMA button to set PLASMA operation.
PLASMA lamp turns ON and plasma electrode unit is energized.
(3) Press PLASMA button again to cancel PLASMA operation.

18
9-10. TIMER OPERATION
1. How to set the time
(1) Check that the current time is set correctly.
NOTE: Timer operation will not work without setting the current time. Initially “0:00” blinks at the current time display of
TIME MONITOR, so set the current time correctly with CLOCK SET button.
How to set the current time
(a) Press the CLOCK set button.
(b) Press the TIME SET buttons ( and ) to set the current time.
• Each time FORWARD button ( ) is pressed, the set time increases by 1 minute, and each time
BACKWARD button ( ) is pressed, the set time decreases by 1 minute.
• Pressing those buttons longer, the set time increases/decreases by 10 minutes.
(c) Press the CLOCK set button.
(2) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(3) Set the time of timer.
ON timer setting
(a) Press ON TIMER button (
START
) during operation.
(b) Set the time of the timer using TIME SET buttons ( and ).
OFF timer setting
(a) Press OFF TIMER button (
STOP
) during operation.
(b) Set the time of the timer using TIME SET buttons ( and ).
Each time FORWARD button ( ) is pressed, the set time increases by 10 minutes; each time BACKWARD button (
) is pressed, the set time decreases by 10 minutes.
2. To release the timer
To release ON timer, press ON TIMER button (
START
).
To release OFF timer, press OFF TIMER button (
STOP
).
TIMER is cancelled and the display of set time disappears.
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
• OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.
• “ ” and “ ” display shows the order of OFF timer and ON timer operation.
PROGRAM TIMER
(Example 2) The current time is 11:00 AM.
The unit turns on at 5:00 PM, and off at 9:00 PM.
NOTE: If the main power is turned OFF or a power failure occurs while ON/OFF timer is active, the timer setting is can-
celled. As these models are equipped with an auto restart function, the air conditioner starts operating with timer
cancelled when power is restored.
9-9. CLEAN ( ) OPERATION
• When CLEAN operation is set, it performs for 40 minutes when unit is stopped after COOL/DRY operation. CLEAN
operation performs when: COOL is operated more than 3 minutes / DRY is operated more than 6 minutes.
• The horizontal vane is slightly opened and the fan is stopped for the first 15 minutes. Then, the horizontal vane is set to
higher than angle 1 and the fan is operated for 25 minutes.

19
EMERGENCY OPERATION switch (E.O.SW)
9-11. 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 AREA 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 thermostat is ON, but 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.
All protective operations such as the coil frost prevention works even in 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.
9-12. 3-MINUTE TIME DELAY OPERATION
When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect
compressor from overload.
Operation mode COOL HEAT
Set temperature 24°C 24°C
Fan speed Med. Med.
Horizontal vane Auto Auto
Vertical vane Straight Straight
The operation mode is indicated by the AREA lamp as following
NOTE:
This is the indication of EMERGENCY OPERATION mode.
AREA setting is not available during EMERGENCY OPERATION.
Lighted
Not lighted
AREA lamp L AREA R
EMERGENCY
COOL
↓
EMERGENCY
HEAT
↓
STOP

20
Insert the negative 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.
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.
3. Troubleshooting procedure
1) First, 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 abnormality indication is flashing on and off before starting service work.
2) Before servicing, check that the connector and terminal are connected properly.
3) When the 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.
Lead wiring Housing point
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS MSZ-FD50VA MSZ-FD50VAS
RESET button
Press RESET button with a thin instrument, and
then use the remote controller.
Remove the front lid and insert batteries.
Then reattach the front lid.
Lock
2
1
5. How to install the horizontal vane
If horizontal vane is not installed correctly, all of the operation indicator lamps will blink.
In this case, install the horizontal vane correctly by following the procedures to .
NOTE: Before installation of the horizontal vane, turn OFF the power supply.
In procedure lock the
stoppers until they click
into place.
TROUBLESHOOTING
10