Mitsubishi Electronics MS24WN User Manual

L

I

S

T

E

D

CUS

SPLIT-TYPE, AIR CONDITIONERS

Revision:

●PARTS LIST have been partially modified.

●Please void OB311.

SERVICE MANUAL

Wireless type
Models

MS24WN (W) · MU24WN

No. OB311

REVISED EDITION-A

INDOOR UNIT
Indication of model name
MS24WN

OUTDOOR UNIT
Indication of model name
MU24WN

Remote
controller

CONTENTS

1. FEATURES·························································3

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

3. SPECIFICATION·················································6

4. DATA···································································8

5. OUTLINES AND DIMENSIONS·······················12

6. WIRING DIAGRAM ··········································14

7. REFRIGERANT SYSTEM DIAGRAM··············15

8. MICROPROCESSOR CONTROL ····················16

9. SERVICE FUNCTIONS ····································25

10. TROUBLESHOOTING ······································27

11. DISASSEMBLY INSTRUCTIONS·····················40

12. PARTS LIST······················································44

13. OPTIONAL PARTS ······················BACK COVER

The Slim Line.
From Mitsubishi Electric.

TM

Revision:

CAPILLARY TUBE (TAPER PIPE)
[0.14X[0.09X1-31/32

E02 784 936

Part number

Part name

Model

MU24WN

Page

47

• Parts No. has been changed due to the color change of outdoor unit parts. WHITE➔NEW WHITE (Brighter)

• Capillary tube has been added to parts list.

1

SWING

LCD wireless
remote controller

SWING

FEATURES

MS24WN

MU24WN

Model

MS24WN

Cooling capacity

22,800 Btu/h

SEER

10.5

“I FEEL CONTROL” IN OUR LCD WIRELESS REMOTE CONTROLLER WITH ON/OFF PROGRAM TIMER

Mitsubishi Electric’s new wireless remote controller incorporates a number of advanced features that provide even greater con-

trol and ease-to-use. It has a liquid crystal display which indicates such information as mode, fan speed and temperature
selected as well as the programmed ON/OFF timer. It is also equipped with “I Feel Control”, a unique Mitsubishi Electric fea­ture that allows the user to adjust the temperature to exactly the level he or she wants simply by tapping the button that
describes present conditions : “Too Cool” or “Too Warm”. The optimum temperature set this way is then memorized for immedi­ate recall whenever the air conditioner is used again.

Select desired air flow direction.
REMOTE-CONTROL OPERATION MODE

Using the remote controller, you can select from five airflow set-

tings to match room layout and the location of people. Also, you
can set the vane to swing automatically.

AUTO-RESTART FUNCTION

The auto restart function restarts the equipment automatically

when power is restored following an outage. Operation resumes in
the mode in which the equipment was running just before the out­age.

HIGH PERFORMANCE ROTARY COMPRESSOR

The advanced design of Mitsubishi Electric’s powerful and energy

efficient rotary compressor results in lower operating costs and
longer service life.

3

2

Installation plate
Installation plate fixing screw 4 x 25 mm(0.16 x 0.98 in.)
Remote controller holder
Fixing screw for 3 3.5 x 16 mm(0.14 x 0.63 in.) (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)

1
7
1
2
2
1
1

1
2
3
4
5
6
7

MS24WN

PART NAMES AND FUNCTIONS

INDOOR UNIT

MS24WN

Grille

Deodorizing filter (option)
(Gray sponge type)

Air cleaning filter (option)
(White bellows type)

Front panel

Air filter

Vertical vane

Operation section

(When the grille is opened)

Emergency operation switch

Air inlet

Remote control
receiving section

Horizontal vane

Remote controller

Display section

Operation indicator lamp

Operation Indicator

Receiving section

ACCESSORIES

OUTDOOR UNIT

MU24WN

4

REMOTE CONTROLLER

ON/OFF

TOO

COOL

PM

AM

TOO

WARM

ON/OFF

FAN

TOO

WARM

TOO

COOL

VANE

MODE

STOP

START

HR.

MIN.

WIDE VANE

LONG

I FEEL

COOL

DRY

PM

CLOCK

AM

RESET CLOCK

FAN

Open the front lid.

Signal transmitting section

Operation display section

OPERATE/ STOP

(ON/ OFF)button

TEMPERATURE buttons

OPERATION SELECT button

FAN SPEED CONTROL button

OFF-TIMER button

HR. button

MIN. button

(TIME SET button)

ON-TIMER button

RESET button

VANE button

(Horizontal vane button)

CLOCK SET button

LONG button

WIDE VANE button

(Vertical vane button)

MS24WN

5

3

Item

Model

Cooling capacity
Power consumption
EER [SEER]
INDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)/ Disconnect switch
Min. ampacity
Fan motor

Airflow Low—Med.—High
Moisture removal

Sound level Low-Med.-High
Cond. drain connection O.D.

Dimensions
Weight

OUTDOOR UNIT MODEL
External finish
Power supply
Max. fuse size (time delay)
Min. ampacity
Fan motor

Compressor

Refrigerant control
Sound level

Dimensions
Weight

REMOTE CONTROLLER
Control voltage (by built-in transformer)
REFRIGERANT PIPING
Pipe size
(Min. wall thickness)

Connection method
Between the indoor

& outdoor units
Refrigerant charge (R22)
Refrigerant oil

(Model)

FAN Dry
COOL Dry(Wet)

W
D
H

Model
Winding resistance (at 68˚F) Ω

W
D
H

Liquid
Gas
Indoor
Outdoor
Height difference
Piping length

Btu/h

W

A
A

F.L.A

CFM
CFM

p

t./h

dB(A

)
in.
in.
in.
in.
lb.

A
A

F.L.A

R.L.A
L.R.A

dB(A

)
in.
in.
in.
lb.

in.
in.

ft.
ft.

oz.

22,800

2,170

10.5 (10.5)
MS24WN

White

115V 60Hz 1[

15

1.1

0.82

431-491-565

402(346)-484(417)-565(487

)

7.6

39-43-47

5/8
43-5/16
8-15/16

12-13/16

40

MU24WN

Munsell 5Y7/1

208/230V 60Hz 1[ 3 wires

25
22

0.87

PH33NPBT

C-R 0.84 C-S 2.09

16
58

Linear expansion valve

55
34-1/4
11-5/8
33-1/2

152

Wireless type

12V DC

Not supplied (optional parts)

3/8 (0.0285

)

5/8 (0.0315

)
Flared
Flared

Max. 25
Max. 50

4 Ib. 5 oz.

27.9

(

MS32N1

)

MS24WN

❈1
❈1

❈1

❈2

Cooling

Maximum

Minimum

Indoor intake air temperature

95˚FDB, 71˚FWB
67˚FDB, 57˚FWB

Outdoor intake air temperature

115˚FDB

67˚FDB

SPECIFICATION

Notes : Test conditions are based on ARI 210/240

❈1 : Rating conditions (cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 95˚FDB, (75˚FWB)
❈2 : Rating conditions (cooling) — Indoor : 80˚FDB, 67˚FWB, Outdoor : 82˚FDB, 65˚FWB

Operating Range

6

w Height difference

should be within
25ft. regardless of
which unit, indoor
or outdoor
position is high.

w Max. Height

difference 25ft.

Additional Piping
Max. length

A

Indoor
unit

Outdoor unit

Outside

diameter

Minimum

Wall

thickness

Outside

diameter

Minimum

Wall

thickness

MS24WN MU24WN

Additional piping

Max. length : ft.

A

50

Gas

Piping size : in. Length of connecting pipe : in.

Liquid

Indoor unit

Outdoor unit

Model

Gas :

Liquid :00

Gas :

Liquid :

16-15/16
19-11/16

[ 5/8

[ 3/8

0.0315 0.0285

MAX. REFRIGERANT PIPING LENGTH & MAX. HEIGHT DIFFERENCE

MAX. HEIGHT DIFFERENCE

7

4

Model

Refrigerant piping length (one way)

1.0

25ft. (std.)

0.954

40ft.

0.923

50ft.

MS24WN

Model

Indoor air

Outdoor intake air DB temperature(˚F

)

71
67
63

TC

27.9

26.4

24.9

SHC

13.9

16.7

19.0

TPC

1.93

1.82

1.74

TC

26.1

24.6

23.0

SHC

13.0

15.5

17.6

TPC

2.12

2.01

1.92

TC

24.5

22.8

21.4

SHC

12.2

14.4

16.4

TPC

2.28

2.17

2.07

TC

22.8

21.2

19.5

SHC

11.3

13.4

14.9

TPC

2.40

2.30

2.21

TC

21.0

19.5

17.8

SHC

10.4

12.3

13.6

TPC

2.50

2.41

2.30

IWB
(˚F)

75

85 95

105

115

MS24WN

(208V/ 230V)

Notes 1. IWB : Intake air wet-bulb temperature.
TC : Total Capacity (x10

3

Btu/h), SHC : Sensible Heat Capacity (x10

3

Btu/h)

TPC : Total Power Consumption (kW)

2. SHC is based on 80˚F of indoor intake air DB temperature.

16

18

20

22

24

26

28

30

65 70 75 80 85 90 95 100 105 110 115

1.4

1.6

1.8

2.0

2.2

2.4

2.6

71
67
63

71
67
63

Total power consumption (kW) Total capacity ( ✕10 Btu/h)

Outdoor intake air DB temperature (°F)

Indoor intake air WB temperature (°F)

Indoor intake air WB temperature (

°F)

Cooling

SHF at rating condition = 0.63

= 487CFM
= 0.16

Airflow

Bypass Factor

208V/230V

208V/230V

DATA

4-1. PERFORMANCE DATA

1) COOLING CAPACITY

MS24WN MU24WN

2) COOLING CAPACITY CORRECTIONS

4-2. PERFORMANCE CURVE

MS24WN
MU24WN

8

4-3. Condensing pressure

70 75 80 85 90 95 100 104(°F)

40

50

60

70

80

90

100

70 75 80 85 90 95 100 104(°F)

160

180

200

220

240

260

280

300

86
80

75
70

Condensing pressure

Outdoor ambient temperature

(PSIG)

86
80
75
70

Indoor DB temperature

Indoor DB temperature

(PSIG)

68

Suction pressure

Outdoor ambient temperature

68

Data is based on the condition of indoor humidity 50%.
Air flow should be set at High.

MU24WN

9

•Both wirings can be applied.

MS24WN

INDOOR UNIT

INDOOR UNIT

115V 60Hz 1[,
2wires

OUTDOOR UNIT

208/230V
60Hz 1[, 3 wires

SIGNAL WIRE
2 wires 12V DC

OUTDOOR UNIT

208/230V
60Hz 1[, 3 wires

115V 60Hz 1[,
2 wires

Disconnect switch
SIGNAL WIRE

2 wires 12V DC

115V

4-4. STANDARD OPERATION DATA

MS24WN

Cooling

22,800

0.63

2.17

MS24WN

115V 60Hz 1[

0.071

0.62

MU24WN

208/230V 60Hz 1[

2.099

9.36/ 8.30

0.67/0.71
250

71
174
115

48
158

25

4 Ib. 5 oz.

80

67

51

50

1,280

487(Wet)

95

—

750/820

1,589/1,765

Capacity
SHF
Input
INDOOR UNIT MODEL
Power supply
Input
Fan motor current
OUTDOOR UNIT MODEL
Power supply
Input
Comp. current
Fan motor current
Condensing pressure
Suction pressure
Discharge temperature
Condensing temperature
Suction temperature
Comp. shell bottom temp
Ref. pipe length
Refrigerant charge (R22)

Intake air temperature

Discharge air temperature

Fan speed (High)
Airflow (High)

Intake air temperature

Fan speed
Airflow

Unit

Btu / h

—

kW

kW

A

kW

A

A
PSIG
PSIG

˚F
˚F
˚F
˚F
ft.
—
˚F
˚F
˚F
˚F

rpm

CFM

˚F
˚F

rpm

CFM

DB

WB

DB

WB

DB

WB

Item

Model

Total

Electrical
circuit

Refrigerant
circuit

Indoor
unit

Outdoor
unit

POWER SUPPLY

10

✻ Control voltage

Power supply voltage to
serial signal circuit is 12V DC.
Voltage between 11+ and 33--

on in-out terminal block will be
12V DC peak.

Model

MS24WN

Mode

FAN

COOL

565
487

Air flow

(CFM)

Air speed

(ft./sec.)

Coverage
range (ft.)

Function

Dry

Wet

34.2

29.4

20.1

17.2

MS24WN MU24WN

Outdoor unit

precharged
(up to 25ft.)

4 lb. 5 oz.

25ft.

0

30ft.

0.81

35ft.

1.62

Refrigerant piping length (one way)

40ft.

2.43

45ft.

3.24

50ft.

4.05

Model

CALCULATION : Xoz. = 0.81/ 5oz./ft. x (Additional Piping Length-25) ft.

Function

Cooling

Standard temperature
Maximum temperature
Minimum temperature

Maximum humidity

DB (˚F)

80
95
67

WB (˚F)

67
71
57

Indoor

78%

DB (˚F)

95

115

67

WB (˚F)

—
—
—

Outdoor

—

Condition

Intake air
temperature

4-5. OPERATING RANGE

Indoor unit

Outdoor unit

Rating

115V 60Hz 1[

208/230V 60Hz 1[

Guaranteed Voltage

MS24WN

MU24WN

Model

Min. 103V

Max. 127V

115V

Min. 198V Max. 253V

208V

230V

(1) POWER SUPPLY

(2) OPERATION

4-6. OUTLET AIR SPEED AND COVERAGE RANGE

● The air coverage range is the figure up to the position where the air speed is 1 ft./sec., when air is blown out horizontally from
the unit properly at the High speed position.
The coverage range should be used only as a general guideline since it varies according to the size of the room and furniture
arranged in the room.

4-7. ADDITIONAL REFRIGERANT CHARGE (R22(oz.))

11

5

6-3/8

3/4

2-5/16

1-7/8

5/16

12-3/8

10-1/161-7/8

1/8

3-7/8

3-7/8

6-13/16

6-13/16

16-5/16 16-5/16

3/168-7/8

8-15/16

9-15/16

31-1/8

2-3/16

42-1/16

43-5/16

12-13/16

Air out

Air in

Insulation [ 1-1/8

Drain hose [5/8
(Connected part O.D)

{

Liquid line [ 3/8 19-11/16
Gas line [ 3/4 16-15/16
Insulation [ 1-15/16 O.D

[ 1-1/4 I.D

Installation plate

Wall hole [ 2-15/16

Wireless remote controller

Installation plate

Indoor unit

OUTLINES AND DIMENSIONS

MS24WN

INDOOR UNIT

Unit: inch

12

MU24WN

Unit: inch

OUTDOOR UNIT

Air intake

Outlet guide
installation hole

Handle for moving

A

17-3/8

7-1/18 20-5/8

1-9/16

Drain hole [1-5/16

7-9/32

Air outlet

11-7/8

2-1/2o7/8 Oval holes

19-11/16

34-1/4

20-5/8

(standard bolt M10)

Air intake

7-9/32

18-7/18

4-1/8

Outdoor Unit-Necessary surrounding clearance

11/16

13

14-1/4

1-9/16 1-1/16

9/16

Terminal block for power line
Terminal block for indoor and outdoor unit connection

Handle for moving
Service panel

Refrigerant-pipe flared

33-1/2

connection [5/8

21-3/4

Refrigerant-pipe flared

17-17/32

2-3/8

1-5/16

Bottom
piping hole

1-5/8

connection [3/8

17-23/32

Knock out hole
for front piping

(refrigerant,drainage
and wiring)

Knock out hole

1-3/4

for right piping
(refrigerant,drainage

and wiring)

2-3/8
4-3/4

13/32

Front opening

13/32

19-11/16

1-3/4

2-1/16

Knock out holes for
power line 2-[1-1/16

7-7/8

Note:Allow adequate
upper clearance

13/32

5-29/32

19-11/16

Service space

Drain hole [1-5/16

Handle
for moving

5-7/16

Rear piping hole

3-3/4

Outdoor Unit-Necessary surrounding clearance
(Concentrated installation)

13/32

4

For 10 units or less

The upper side must be open.

7-7/8

39-3/8

2-U-shaped
notched
holes

Side air intake

Rear fresh
air intake

9/32

A

11-5/8

15/16

Conduit hole

NOTE: Do not wire12V DC and

115V AC in same conduit hole.

15/16

1/2

R1/4

1-5/16

R13/16

11/16

Front right piping holes­detail figures

2-9/16

R13/16

1 max.

3-1/8

Standard bolt length

13

6

SYMBOL

TB2
T61
X52
52C

SYMBOL

MF
NR61
RT62
RT63
SR61

TB1

SYMBOL

C1
C2

DSAR

F61

LEV

MC

NAME

NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE(3.15A)
EXPANSION VALVE COIL
COMPRESSOR(INNER PROTECTOR)

OUTDOOR FAN MOTOR(INNER PROTECTOR)

VARISTOR

DISCHARGE TEMPERATURE THERMIST OR

AMBIENT TEMPERA TURE THERMIST OR
SOLID STATE RELAY
TERMINAL BLOCK

TERMINAL BLOCK
TRANSFORMER

COMPRESSOR AUXILIARY RELAY

COMPRESSOR CONTACTOR

TAB12

POWER

FROM OUTDOOR
UNIT
CONNECTING
WIRES

TO OUTDOOR
UNIT
CONNECTING
WIRE

SUPPLY
115V
1 phase
60Hz

CN201

RT13

121

CN

CN211

CN112

TO OUTDOOR
UNIT
CONNECTING
WIRES
12V DC

3

F11

VLT

1-

3+

15

3

REMOTE
CONTROLLER

MV2 MV2 MV1

BLK
GRY

TRANS

HIC1

C11

N

L1

BLK

ORN

WHT

BRN

YLW

RED

ELECTRONIC CONTROL P.C. BOARD

NR11

RED

MF

RT12

CN
151

CN
101

3

DISPLAY
P.C.BOARD

RECEIVER
P.C.BOARD

CN
102

SR141

1
3
4

4
3
2
1

RT11

111

CN

1
2
3
4

TB

w

(

)

w A disconnect may be required by local code.

SYMBOL

RT12
RT13

SR141

TB

SYMBOL

MV1

MV2
NR11
RT11

SYMBOL

C11

F11

HIC1

MF

NAME

NAME NAME
INDOOR FAN CAPACITOR
FUSE(3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR (INNER PROTECTOR)

VANE MOTOR(HORIZONTAL)
VANE MOTOR(VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMIST OR

INDOOR COIL THERMISTOR(MAIN)
INDOOR COIL THERMISTOR(SUB)
SOLID STATE RELAY
TERMINAL BLOCK

WIRING DIAGRAM

MS24WN

MODEL WIRING DIAGRAM

INDOOR UNIT

NOTE:1. About the outdoor side electric wiring, refer to the outdoor unit electric wiring diagram for servicing.

2. Use copper conductors only.(For field wiring)

3. Symbols below indicate;
: Terminal block, : Connector

SG79J618H02

MU24WN

MODEL WIRING DIAGRAM

OUTDOOR UNIT

FROM INDOOR UNIT
CONNECTING WIRE

FROM INDOOR UNIT
CONNECTING WIRES
12V DC

TO INDOOR UNIT
CONNECTING
WIRES
115V
1 phase 60Hz

POWER
SUPPLY
208/230V
1 phase 60Hz

GROUND

NOTE:1. About the indoor side electric wiring, refer to the indoor unit electric wiring diagram for servicing.

2. Use copper conductors only.(For field wiring)

3. Symbols below indicate;
: Terminal block, : Connector

TB2

3

1

N

L1

TB1

L1

N

L2

+

-

BLK

RED

RED

GRN/YLW

OUTDOOR ELECTRONIC CONTROL P.C. BOARD

RED

BLU

BLU

DSAR

14

RT62 RT63

CN662 CN724

X52

T61

LEV

6

SR61

A2 A1

52C

MF

WHTWHT

BLK

ORN

RED

3456

21

RED

C2

ORN

3

CN711

TAB52

X52

COM

NO

F61

ORN
VLT
BLU
RED

CN730

WHT

RED
BLK

1
3
5
7

NR61

1

2

52C

C1

12

BLK

C

S

MC

SG79J606H02

BLU

R

7

Indoor
heat
exchanger

Outdoor
heat
exchanger

Flared connection

Room temperature
thermistor
RT11

Indoor coil
thermistor
RT13(sub)

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube
O.D.0.14✕I.D.0.09✕1-31/32

Refrigerant flow in cooling

Compressor

Refrigerant pipe [5/8
(with heat insulator)

Refrigerant pipe [3/8
(with heat insulator)

Indoor coil
thermistor
RT12(main)

LEV

Strainer

Strainer

Accumulator

Ambient
temperature
thermistor
RT63

Strainer

#50

Capillary tube
O.D.0.16✕I.D.0.09✕7-7/8
(Upper path)

Capillary tube
O.D.0.16✕I.D.0.09✕3-15/16
(Lower path)

SERVICE
PORT

SERVICE
PORT

FUSIBLE
PLUG

#100

#100

REFRIGERANT SYSTEM DIAGRAM

Unit: inch

MS24WN

INDOOR UNIT

MU24WN

OUTDOOR UNIT

15

8

lighted
not lighted

Approx. 4-F
or more

Difference
between set
temperature
and room
temperature

Approx. 4-F
or less

This shows that the
air conditioner is
operating to reach
the target temperature.
Please wait until the
target temperature is
obtained.

This shows that the
room temperature is
approaching the
target temperature.

Operation stateIndication

Operation Indicator

Operation Indicator lamp

The operation indicator at the right side of the indoor
unit indicates the operation state.

INDOOR UNIT DISPLAY SECTION

• The following indication applies regardless of shape
of the indicator.

MICROPROCESSOR CONTROL

MS24WN MU24WN

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Operation display section

OPERATE/ STOP
(ON/ OFF)button

VANE button

(Horizontal vane button)

OPERATION SELECT button

WIDE VANE button

(Vertical vane button)

RESET button

I FEEL

FAN

MODE

ON/OFF

ON/OFF

COOL

DRY

TOO

WARM

CLOCK

TOO

WARM

FAN

VANE

WIDE VANE

LONG

RESET CLOCK

PM

AM

TOO

COOL

PM

AM

TOO

COOL

STOP

START

HR.

MIN.

TEMPERATURE buttons

FAN SPEED CONTROL button

OFF-TIMER button

ON-TIMER button

HR. button
MIN. button

(TIME SET button)

CLOCK SET button

LONG button

Once the operation mode is set, the same operation mode
can be repeated by simply turning the
OPERATE/STOP(ON/OFF) button ON.
Indoor unit receives the signal with a beep tone.
When the system turns off, 3-minute time delay will operate to
protect system from overload and compressor will not restart
for 3 minutes.

8-1. “I FEEL CONTROL” ( ) OPERATION

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

controller. OPERATION INDICATOR lamp of the indoor
unit turns on with a beep tone.

(2) Select “I FEEL CONTROL”( ) mode with the OPERA-

TION SELECT button.

(3) The operation mode is determined by the room temper-

ature at start-up of the operation.
Initial room temperature

77-F or more
more than 55-F,

less than 77-F

● Once the mode is fixed, the mode does not change
by room temperature afterwards.

● Under the ON-TIMER ( ) operation, the mode
is determined according to the room temperature at
the set time the operation starts.

● When the system is stopped on the remote controller,
and restarted within 2 hours in “I FEEL CONTROL”
( ) mode, the system operates in previous mode
automatically regardless of the room temperature.

Operation timer chart

Example

mode

COOL mode of

“I FEEL CONTROL“

DRY mode of

“I FEEL CONTROL”

Previous operation

COOL mode of
“I FEEL CONTROL” or
COOL mode

When the system is restarted after 2 hours and more,
the operation mode is determined by the room temper­ature at start-up of the operation.

Operation timer chart
Example

Previous operation

COOL mode of
“I FEEL CONTROL”
or COOL mode

16

Restart

COOL mode of
“I FEEL CONTROL”

Restart

COOL or DRY mode of
“I FEEL CONTROL” that
determined by room
temperature at start-up
of the operation.

(4) The initial set temperature is decided by the initial room temperature.

TOO

COOL

TOO

WARM

Mode

COOL mode of

"I FEEL CONTROL"

DRY mode of

"I FEEL CONTROL"

Initial room temperature Initial set temperature

79-F or more

77-F to 79-F

more than 55-F, less than 77-F

Initial room temperature

75-F

minus 4-F

Initial room temperature

minus 4-F

w 1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-

less of the room temperature at restart.
The set temperature is calculated by the previous set temperature.

(5) TEMPERATURE buttons

In “I FEEL CONTROL” ( ) mode, set temperature is decided by the microprocessor based on the room temperature.

In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too warm.
Each time the TOO WARM or TOO COOL button is pressed the indoor unit receives the signal and emits a beep tone.

● Fuzzy control

When the TOO COOL or TOO WARM button is pressed the microprocessor changes the set temperature, considering
the room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user’s preference to heat or
cool. So this is called “Fuzzy control”, and works only in “I FEEL CONTROL” mode.
In DRY mode of “I FEEL CONTROL”, the set temperature doesn’t change.

…

To raise the set temperature 2~4 degrees(°F)

❈1

…

To lower the set temperature 2~4 degrees(°F)

8-1-1. COOL mode of “I FEEL CONTROL”

1. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In AUTO the fan speed is as follows.

Initial temperature difference

Fan speed

Room temperature minus set temperature : 3 degrees or more········································High
Room temperature minus set temperature : Between 2 and 3 degrees····························Med.
Room temperature minus set temperature : less than 2 degree·······································Low

2. Coil frost prevention

1 Temperature control

When the indoor coil thermistor RT12 or RT13 reads 30°F or below, the coil frost prevention mode starts immediately.
However the coil frost prevention doesn’t work for 5 minutes since the compressor has started.
The indoor fan operates at the set speed and the compressor stops for 5 minutes.

After that, if RT12 or RT13 still reads below 30°F this mode prolonged until the RT12 and RT13 reads over 30°F.

2 Time control

When the three conditions as follows have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes.
a. Compressor has been continuously operating.
b. Indoor fan speed is Low or Med.
c. Room temperature is below 79°F.
When compressor stops, the accumulated time is cancelled and when compressor restarts, time counting starts
from the beginning.
Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds
79°F. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.

Difference between room
temperature and set tem­perature during operation

2 deg. 3 deg.

4 deg.

17

Operation chart

Example

ON

ON

Compressor
Outdoor fan

Indoor fan

3. Discharge temperature protection

The compressor is controlled by the temperature of discharge temperature thermistor RT62 for excess rise protection of
compressor discharge pressure.

• Compressor
When the temperature of discharge temperature thermistor RT62 goes to 248°F or more, the compressor is turned OFF.
After 3 minutes since the compressor has been turned OFF, if the temperature of discharge temperature thermistor RT62
becomes 212°F or less, the compressor is turned ON.

8-1-2. DRY mode of “I FEEL CONTROL”

The system for dry operation uses the same refrigerant circuit as the cooling circuit.
The compressor and the indoor fan are controlled by the room temperature.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature
decrease.

1. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button.
However, in AUTO fan operation, fan speed becomes Low.

2. The operation of the compressor and indoor / outdoor fan

Compressor operates by room temperature control and time control.

Set temperature is controlled to fall 4°F from initial room temperature.

Indoor fan and outdoor fan operate in the same cycle as the compressor.

• When the room temperature is 73°F or over:
When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

• When the room temperature is under 73°F.
When the thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

Operation time chart

Example

OFF

(continuously at set speed)

ON

ON

OFF

ON

Thermostat

Indoor fan

Outdoor fan
Compressor

3. Coil frost prevention

The operation is as same as coil frost prevention during COOL mode of “I FEEL CONTROL”.
Indoor fan operates at the set speed and the compressor stops for 5minutes, because protection (Coil frost prevention) has
the priority. However when coil frost prevention works while the compressor is not operating, it’s speed becomes Low.

OFF

OFF

OFF

ON

ON

8 min.

OFF

OFF

ON

ON

3 min.

4 min.

OFF

ON

OFF

ON

OFF

1 min.

18

86

77

68

59

50

50 59 68 77 86 95

95

-F

-F

Set temperature

Initial room temperature

Set temperature and initial temperature in DRY mode

8-2. COOL ( ) OPERATION

High

Med.

Low

High

(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 the OPERATION SELECT button.
(3) Press TEMPERATURE buttons.

(TOO WARM or TOO COOL button) to select the desired temperature.

The setting range is 59 ~ 89°F.

w Indoor fan continues to operate regardless of thermostat’s OFF-ON at set speed.
w Coil frost prevention is as same as COOL mode of “I FEEL CONTROL”.

8-3. 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 the OPERATION SELECT

button.
(3) The microprocessor reads the room temperature

and determines the set temperature. Set tempera-

ture is as shown on the right chart.

Thermostat (SET TEMP.) does not work.

The other operations are same as DRY mode of “I

FEEL CONTROL”.
(4) DRY operation will not function when the room tem-

perature is 55°F or below.

8-4. FAN( d )OPERATION

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

OPERATION INDICATOR lamp of the indoor unit
turns ON with a beep tone.

(2) Select FAN mode with the OPERATION SELECT

button.
Only indoor fan operates. Outdoor unit does not
operate.

8-5. FAN MOTOR CONTROL

(1) Rotational frequency feedback control

The indoor fan motor is equipped with a rotational frequency sensor, and outputs signal to the microprocessor to

feedback the rotational frequency. Comparing the current rotational frequency with the target rotational frequency

(High,Med.,Low), the microprocessor controls, SR141 and adjusts fan motor electric current to make the current

rotational frequency close to the target rotational frequency. With this control, when the fan speed is switched,

the rotational frequency changes smoothly.

(2) Fan motor lock-up protection

When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot

detect the signal for 12 seconds) the fan motor is regarded locked-up. Then the electric current to the fan motor is shut

off. 3 minutes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION

INDICATOR lamp flashes on and off to show the fan motor abnormality. (Refer to page 29.)

19

AUTO

Horizontal Middle

Downward

Swing

8-6. AUTO VANE OPERATION

1. Horizontal vane

(1) Vane motor drive

This model is equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of the
motor are controlled by pulse signals (approx. 12V) transmitted from microprocessor.

(2) The horizontal vane angle and mode change as follows by pressing the VANE button.

(3) Positioning

The vane is once pressed to the vane stopper below to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When the OPERATE/STOP(ON/OFF) button is pressed(POWER ON/OFF).
(b) When the vane control is changed from AUTO to MANUAL.
(c) When the SWING is finished.
(d) When the test run starts.
(e) When the power supply turns ON.

(4) VANE AUTO ( ) mode

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

1 In COOL and DRY operation

Vane angle is fixed to Angle 1.

2 In FAN operation

Vane angle is fixed to Angle 4.

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

When the following cases occur, the horizontal vane returns to the closed position.
(a) When the OPERATE/STOP(ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When the ON-TIMER is on standby.

(6) Dew prevention

During COOL or DRY operation at Vane Angle 4 or 5 when the compressor cumulative operation time exceeds 1 hour,
the vane angle automatically changes to Angle 1 for dew prevention.

(7) SWING MODE ( )

By selecting SWING mode with the VANE button, the horizontal vane swings vertically. The remote controller displays

“”.

(8) LONG MODE ( )

By pressing the LONG button indoor fan speed becomes faster than setting fan speed on the remote controller, and the
horizontal vane moves to the position for LONG mode. The remote controller displays “ ”. LONG mode is cancelled

when the LONG button is pressed once again or the VANE button is pressed.

20

COOL / DRY

Fan speed : Faster
Solid arrow : When the LONG mode is used.
Dotted arrow : When the LONG mode is not used.

FAN

• In the following example, the vertical vane is set to (front.).

About 100-

Horizontal AIR FLOW blowing range

2. Vertical vane

(1) Vane motor drive

This model is equipped with a stepping motor for the vertical vane. The rotating direction, speed, and angle of the motor
are controlled by pulse signals (approx. 12V) transmitted from indoor microprocessor.

(2) The vertical vane angle and mode changes as follows by pressing the WIDE VANE button.

23

45SWING

61

Air flow direction
Air flow blowing range

(3) Positioning

The vane is once pressed to the vane stopper to confirm the standard position and then set to the desired angle.

Confirming of standard position is performed under following conditions.

(a) When the OPERATE/STOP(ON/OFF) button is pressed (POWER ON/OFF).

(b) When the SWING is started or finished.

(c) When the power supply turns ON.

(4) SWING MODE ( )

By selecting SWING mode with the WIDE VANE button, the vertical vane swings horizontally. The remote controller

displays “ ”. The vane moves right and left in the width of Angle 4 repeatedly.

(5) WIDE MODE ( )

By selecting WIDE mode with the WIDE VANE button, indoor fan speed becomes faster than setting fan speed on the

remote controller(W). The remote controller displays “ ”.

W Indoor fan speed becomes faster than setting fan speed on the

remote controller even when or is selected.

8-7. TIMER OPERATION

1. How to set the timer

(1) Press OPERATE/STOP(ON/OFF) button to start the air conditioner.
(2) Check that the current time is set correctly.

NOTE : Timer operation will not work without setting the current time. Initially “AM0:00” blinks at the current time display of

(3) Press ON/OFF TIMER buttons to select the operation.

TIMER MONITOR, so set the current time correctly with CLOCK SET button.

“ON-TIMER” button... AUTO START operation (ON timer)

“OFF-TIMER” button... AUTO STOP operation (OFF timer)

21

OPERATION INDICATOR lamp

• The following indication applies regardless
of shape of the indicator.

Press once <Cool>

Press once again <Stop>

PM

AM

PM

PM

EMERGENCY OPERATION
switch

(4) Press HR. and MIN. button (TIME set button) to set the timer. Time setting is 10-minute units.

HR. and MIN. button will work when “ ” or “ ”

mark is flashing.

These marks disappear in 1 minute.
After setting the ON timer, check that OPERATION INDICATOR lamp of the indoor unit lights.

NOTE1 :Be sure to place the remote controller at the position where its signal can reach the air conditioner even during

TIMER operation, or the set time may deviate within the range of about 10 minutes.

NOTE2 :Reset the timer in the following cases, or the set time may deviate and other malfunctions may occur.

● Apower failure occurs.

● The circuit breaker functions.

2. Cancel

TIMER setting can be cancelled with the ON/OFF TIMER buttons.
To cancel the ON timer, press the “
To cancel the OFF timer, press the “

ON-TIMER

OFF-TIMER

” button.

” button.

TIMER is cancelled and the display of set time disappears.

PROGRAM TIMER

● The OFF timer and ON timer can be used in combination.

● “ ”and “ ” display shows the order of the OFF timer and ON timer operation.

(Example 1) The current time is 8:00 PM.

The unit turns off at 11:00 PM, and on at 6:00 AM.

(Example 2) The current time is 11:00 AM.

The unit turns on at 5:00 PM, and off at 9:00 PM.

NOTE : TIMER setting will be cancelled by power failure or breaker functioning.

8-8. EMERGENCY-TEST OPERATION

In case of test run operation or emergency operation, use the EMERGENCY OPERATION switch on the front of the
indoor unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of remote
controller run down. 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. The indoor fan speed runs at
High speed and the system is in continuous operation. (The thermostat is ON.)
After 30 minutes of test run operation the system shifts to EMERGENCY COOL MODE with a set temperature of 75°F.
The fan speed shifts to Med. speed.
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 the EMERGENCY OPERATION switch is pressed again or the unit receives any sig­nal from the remote controller. In case of latter normal operation will start.

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

22

8-9. LEV control

Controlled range

Basic specification

Minimum : 54 pulse, Maximum : 500 pulse

Drive speed

30 ~ 90 pulse / second

Opening set

Stop of indoor unit

Opening in stop : 150 pulse ➔ LEV opening is set to becomes 500 pulse
after 3 minutes passed.

Remote controller ON

LEV positioning (LEV is closed completely at once)

Power ON (Breaker ON)

LEV is positioned. However, afterwards, LEV is not positioned at the first
remote controller ON.

Approximate for 2 minutes since
compressor has started.

Opening is set by the initial opening.
(Initial opening is set according to each operation modes and
outer temperature conditions.)

From approximate 2 minutes to
approximate 13 minutes
(for 11 minutes) since compressor
has started.

Opening is set by standard opening.
(Standard opening is set according to each operation modes and
outer temperature conditions.)

After 13 minutes passed since
compressor has started.

LEV opening is corrected to be once every 2 minutes so that discharge
temperature becomes the target discharge temperature.
(When the discharge temperature is lower than target one : LEV is corrected in
closed direction, when the discharge temperature is higher than target one :
LEV is corrected in opening direction.)

At thermostat OFF

Opening in stop : 150 pulse ➔ LEV is set to the initial opening after about
3 minutes passed.

At thermostat ON

Same as the starting of compressor operation

At remote controller OFF

Opening in stop : 150 pulse ➔ LEV is set so that the opening is opened
completely at the speed of 4 pulse every 5 seconds in opening after about
3 minutes passed.

General operation

The setting is always in opening direction.
(To close the LEV, it is closed to the pulse smaller than the one which is
set finally. Then the LEV is opened to the final setting pulse.)

Rank

Ta (F-)
more than Tb+18
Tb+9 to Tb+18
Tb+4 to Tb+9
Tb-4 to Tb+4
Tb-9 to Tb-4
Tb-18 to Tb-9
less than Tb-18

100 pulse or less

(Pulse)
Cooling

5
2
1
0

-1

-2

-5

NOTE : Discharge temperature : Ta, Target discharge temperature : Tb

100 pulse or more

(Pulse)

Cooling

20
10

2
0

-2

-5

-10

Opening immediately before having stopped last time

LEV (Expansion valve) is controlled by “Thermostat ON” commands given from the unit.

(1) LEV opening correction by discharge temperature

The LEV opening is corrected according to the temperature difference between target discharge temperature (Tb) and
actual discharge temperature (Ta).
1 The LEV correction is used properly for two kinds according to the LEV opening status at operation off.

23

2 When the temperature difference RT between indoor coil thermistor (main) RT12 and indoor coil thermistor (sub)

Ta (F-)

more than Tb+18
Tb+9 to Tb+18
Tb+4 to Tb+9
Tb-4 to Tb+4
Tb-9 to Tb-4
Tb-18 to Tb-9
less than Tb-18

less than 4deg.

(Pulse)

20
10

2
0

-2

-5

-10

NOTE : Discharge temperature : Ta, Target discharge temperature : Tb

6deg. or more

(Pulse)

60
20
10

0

-2

-5

-10

RT

4deg. or more and less than 6deg.

(Pulse)

60
20
10

0

-2

-5

-10

Tb (-F)

171
144
136

COOL (Normal)
COOL ( RT is less than 4deg., or RT is 4deg. or more and less than 6deg..)
COOL ( RT is 6deg or more.)

NOTE : Target discharge temperature : Tb

Operation mode

NOTE : Opening increases and decreases to be in the target discharge temperature during operation.

Opening
completely

Positioning

Power ON

Initial opening

Standard opening

Remote
controller
ON

➔

Operation

Thermostat
OFF

Standard opening

Thermostat
ON

Opening in stop

Initial opening

Operation

Opening in stop

Remote
controller
OFF

Opening
completely

Remote
controller
ON

➔

Positioning

Initial opening

Standard opening

Operation

Time

LEV opening

Open

Close

RT13 in the indoor unit is 4deg. or more for a fixed time at cool or dry operation, the target discharge temperature is
changed. After the temperature is changed, when temperature difference RT is 6deg. or more, the target

temperature is changed again. The LEV opening is controlled based on the changed target discharge temperature
and the temperature difference RT.

The target discharge temperature (Tb) is set according to the operation mode or the unit status as follows.

NOTE : When the discharge temperature (Ta) is 122°F or less on the cool operation LEV opening is set in 54 pulse.

When this state continues for 20 minutes, the compressor is stopped and restarts in 3 minutes.
When the compressor is stopped, the indoor unit indicates the abnormality of refrigerant system and stops.
(OPERATION INDICATOR lamp is 10-time flashing on and off.)

(2) LEV time chart

24

9

No. 1 unit
No. 2 unit
No. 3 unit
No. 4 unit

1 unit operation
No modification

–
–
–

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

SERVICE FUNCTIONS

MS24WN

9-1. TIMER SHORT MODE

For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to page 37.)

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.)

9-2. 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 indoor unit number.

How to modify the remote controller P.C. board

Remove batteries before modification.
The board has a print as shown below :

NOTE : For remodelling, take out the batteries

and press the
OPERATE/STOP(ON/OFF)button
twice or 3 times at first.
After finish remodelling, 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

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 accepts 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.

25

9-3. AUTO RESTART FUNCTION

JR07

IC152

CN151

CN112

CN111

CN121

SW1

IC101

RA102

C11

CN201

CN211

TAB12

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.
When the main power is turned off and then turned back on, the unit restarts automatically in the memorized set
conditions approximately after 3 minutes.

How to release “AUTO RESTART FUNCTION”

1 Turn off the main power for the unit.
2 Pull out the indoor electronic control P.C. board and the display P.C.board. (Refer to page 40.)
3 Solder the Jumper wire or the Resistor 220Ω to the JR07 on the indoor electronic control P.C.board. (Refer to page 37.)

Operation

1 If the main power (115V AC) has been cut, the operation settings remain.
2 After the power is restored, the unit restarts automatically according to the memory. (However, it takes at least 3 minutes

for the compressor to start running.)

NOTE:

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

controller.

•If the 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 appliances not to turn on at the same

time.

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

the starting current of all the compressors may flow simultaneously at restart.
Therefore, 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. (time delay)

26

10

Lead wiring

Housing point

RESET button

Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.

TROUBLESHOOTING

MS24WN MU24WN

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 mis-wiring.

2. Take care the following during servicing.

1) Before servicing the air conditioner, first be sure to turn off the remote controller to stop the unit, 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 electronic
control P.C. board.

3) When removing the electronic control 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) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.

4) When troubleshooting, refer to the flow chart on page 28 and the check table on page 29.

4. How to replace batteries

Weak batteries may cause the remote controller malfunction.

In this case, the remote controller can be repaired only by the battery replacement. To operate the remote controller nor-

mally, replace the batteries in the following order.

This remote controller has the RESET button. After refilling new batteries, press the RESET button with tip end of ball

point pen or the like, and then use the remote controller.

1 Remove the front lid and insert batteries.

Then reattach the front lid.

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

27

2 Press the RESET button.

10-2. Instruction of troubleshooting

Start

Indoor unit
operates.
Outdoor unit
doesn't
operate.

Indoor unit
doesn't receive
the signal from
remote controller.

OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.

Outdoor unit
operates in
only Test Run
operation.

Outdoor unit
doesn't
operate
even in
Test Run
operation.

Indoor unit
operates, when
the
EMERGENCY
OPERATION
switch is pressed.

Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is pressed.

Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage" on
page 37.

Refer to D
"Check of
outdoor unit"
on page 33.

Refer to B
"Check of
remote controller
and receiver
P.C. board"
on page 31.

Flash on and
off at 0.5­second
intervals
Cause:
Indoor/
Outdoor unit

• Mis-wiring

3-time flash
Cause:
Indoor unit

• Trouble of
indoor fan
motor

6-time flash
Cause:
Outdoor unit

• Trouble of
thermistor
in outdoor
unit

7-time flash
Cause:
Outdoor unit

• Trouble of
outdoor
control
system

Refer to F
"How to check
mis-wiring
(When
outdoor unit
doesn't oper
ate)"
on page 35.

Refer to A
"Check of
indoor fan
motor"
on page 31.

Refer to H
"Check of
outdoor
thermistor"
on page 36.

Replace the
deicer
P.C. board.

10-time flash
Cause:
Outdoor unit

• Trouble of
low

discharge
temperature
protection

Refer to G
"Check of
LEV"
on page 36.

4-time flash
Cause:
Indoor unit

• Trouble of
indoor unit
control
system

Replace the
indoor
electronic
control
P.C. board.

1. Check indoor /
outdoor
connecting wire.

2. Refer to C
"Check of indoor
electronic control
P.C. board"
on page 32.

Outdoor unit
doesn't
stop even
if indoor unit
stops.

Refer to E
"Check of
outdoor unit"
on page 34.

w1.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.

2-time flash
Cause:
Indoor unit

• Trouble of
room temp­ erature/
indoor coil
thermistor

Check room
temperature
thermistor
and indoor
coil thermis­tor.
Refer to
"Test point
diagram and
voltage"
on page 37.

28

• The following indication applies regardless of shape of the indicator.

Operation Indicator

· Flashing of the OPERATION INDICATOR lamp (on the left-hand side)
indicates possible abnormalities.

· The OPERATION INDICATOR lamp (on the left-hand side) is lighted during
normal operation.

flashing

No.

1

2

4

5

6

SymptomOperation indicator lamp Detection method

Checkpoint

0.5-second ON

0.5-second OFF

Mis-Wiring

Outdoor
thermistors

Outdoor
control
system

Indoor coil
thermistor

3 minutes after power supply turns ON, when
serial signal is not received.

<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.
However, discharge temperature thermistor is
abnormal when open circuit is detected more
than 10 minutes after compressor start-up.

When it cannot properly read data in the
nonvolatile memory of the deicer P.C. board,
outdoor unit stops.

• Replace the deicer P.C.
board.
Refer to H "Check of outdoor

thermistor" on page 36.

• Reconnect the connector.

• Replace the deicer P.C.
board.

• Refer to F "How to check

mis-wiring" on page 35.

3

Indoor fan
motor

7

Low
discharge
temperature
protection

When discharge temperature has been 122°F
or less on cool operation, or is 120°F or less
on heat operation for 20 minutes.

Abnormal

point

Outdoor unit
does not
operate.

Room
tempera­ture
thermistor

2-time flash

2.5-second OFF

Detect Indoor coil/room temperature
thermistor short or open circuit every 8
seconds during operation.

• Refer to the characteristics of
main indoor coil thermistor,
sub indoor coil thermistor,
and room temperature
thermistor on page 37.

3-time flash

2.5-second OFF

Indoor fan
repeats 12
seconds ON
and 3
minutes
OFF.
When the
indoor fan
breaks, the
fan keeps
stopping.

When rotational frequency feedback signal is
not emitting during 12-second indoor fan
operation.

• Refer to A "Check of
indoor fan motor" on page 31.

4-time flash

2.5-second OFF

Indoor
control
system

When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.

Outdoor unit
does not
operate.

Outdoor unit
does not
operate.

• Replace the indoor electronic
control P.C. board.

6-time flash

2.5-second OFF

• Refer to G "Check of LEV" on
page 36.

• Check refrigerant circuit and
refrigerant amount.

Outdoor unit
does not
operate.

Outdoor unit
does not
operate.

Outdoor unit
does not
operate.

7-time flash

2.5-second OFF

10-time flash

2.5-second OFF

1. Troubleshooting check table

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

NOTE : When the indoor unit has started operation and the above detection method has detected an abnormality (the first

detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with the
OPERATION INDICATOR lamp flashing on and off.

29

Part name FigureCheck method and criterion

Measure the resistance between the terminals with a tester.
(Part temperature 14˚F ~ 104˚F)

Compressor(MC)
INNER

PROTECTOR
320i 9-F OPEN
198i20-F CLOSE

Indoor fan motor(MF)
INNER

PROTECTOR
275i 9-F OPEN
187i27-F CLOSE

Normal

Terminal

C – R
C – S

0.74 " ~ 0.91 "

1.84 " ~ 2.26 "

Abnormal

Open or

short-circuit

Measure the resistance with a tester.
(Part temperature 14˚F ~ 104˚F)

Color of lead wire

WHT – BLK
BLK – RED

Abnormal

Open or

short-circuit

Normal
35 " ~ 39 "
65 " ~ 71 "

Measure the resistance with a tester.
(Part temperature 50˚F ~ 86˚F)

Normal

8 k" ~ 20 k"

Abnormal

Open or short-circuit

Room temperature
thermistor(RT11)

Indoor coil thermistor
(RT12(main), RT13(sub))

Discharge temperature
thermistor(RT62)

Ambient temperature
thermistor(RT63)

Outdoor fan motor(MF)
INNER

PROTECTOR
293i14-F OPEN
190i27-F CLOSE

Horizontal vane
motor(MV1)
Vertical vane
motor(MV2)

LEV(Expansion valve)

Measure the resistance with a tester.
Before measurement, hold the thermistor with your hands to warm it up.
(Part temperature 32˚F ~ 104˚F)

Normal

120 k" ~ 800k"

Abnormal

Open or short-circuit

Normal

5 k" ~ 60 k"

Abnormal

Open or short-circuit

Motor part

Sensor part

Measure the resistance between the terminals with a tester.
(Part temperature 50˚F ~ 86˚F)

Measure the voltage power ON.

Color of lead wire

BRN – YLW
YLW – GRY

Abnormal

Remain 0V or 5V

Normal

4.5 ~ 5.5V

(When fan revolved one time)

0V➔5V➔0V

(Approx.)

Measure the resistance between the terminals with a tester.
(Part temperature 14˚F ~ 104˚F)

Color of lead wire

WHT – BLK

BLK – RED

Abnormal

Open or

short-circuit

Normal
51 " ~ 62 "
50 " ~ 61 "

Normal

282" ~ 306 "

Abnormal

Open or short-circuit

Measure the resistance between the terminal with a tester.
(Part temperature 50°F ~ 86°F)

Color of lead wire

WHT – RED
RED – ORN

YLW – BRN
BRN – BLU

Abnormal

Open or

short-circuit

Normal

30.3 " ~ 37.0 "

Measure the resistance with a tester.
(Part temperature : 14˚F ~ 104˚F)

P

P

R

C

S

RED

BLK

WHT

MAINAUX.

1
2
3

RED

BLK

MAIN

AUX.

YLW
GRY

BRN

WHT

1
2
3

RED

AUX.

MAIN

ORN

BLK

WHT

P

RED

YLW

BRN

ORN

GRN

ROTOR

LEV

WHT

6

RED1
ORN4

YLW5

BRN2

BLU3

:INNER PROTECTOR

P

2. Trouble criterion of main parts

MS24WN MU24WN

30

When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.

A

Check of indoor fan motor

Turn OFF the power supply.
Check connector CN211 visually.

No

Reconnect the lead wires.

Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board.
Measure resistance between lead wires : No.1 and No.4 and then No.3 and No.4.

Are lead wires connected?

Is resistance 0 (short circuit) or ∞ (open circuit)?

Repair or replace the indoor fan motor.

Yes

Yes ( 0 or ∞ )

Is soldering point of the connector

correctly soldered?

Yes

Turn ON the power supply. Stop it if the unit operate.
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure

No

(others)

voltage between No.2(+) and No.3(-) on CN121.

No

Does voltage repeat 0V DC and 5V DC?

Replace the indoor electronic control P.C. board.

No

Resolder it.

Yes

Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.

B

Check of remote controller and receiver P.C. board

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

Switch on the remote controller.

Is LCD display on the remote
controller displayed?

Yes

No
(not clear)

Replace the batteries.(Refer to page 27.)

Remove the batteries, then set them back
and press the RESET button. 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 switch on

the remote controller.

Is noise heard from radio?

Yes

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

No

Measure the voltage between receiver P.C. board connector CN301 No.1(+) and No.3(-) when remote
controller button is pressed.

Is the voltage approx. 4V DC?

No(5V or 0V DC)

Replace the receiver P.C. board.

No

Yes

Yes

Replace the remote controller.

● Reinstall the unit away from lights.

● Attach a filter on receiving part.

Replace the indoor electronic control P.C.
board.

31

The unit doesn’t operate with the remote controller.

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

Replace the fuse.

Is fuse(F11) blown?

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

Replace the fan
motor.

Replace the
indoor electronic
control P.C. board.

Is winding
resistance of
fan motor 0 "?

Is winding
resistance of
vane motor 0 "?

No

Yes

Replace the vane
motor.

Turn OFF the
power supply.

Turn OFF the
power supply.

No

Yes

Yes

Is varistor(NR11) burnt?

Replace the varistor.

Yes

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

No

No

Does the unit operate with the remote controller?
Does the OPERATION INDICATORE lamp light up
by pressing the EMERGENCY OPERATION switch?

No

Yes

Be sure to check both resistance.

Varistor (NR11)

Indoor electronic
control P.C. board

Fuse (F11)

Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.

C

Check of indoor electronic control P.C. board

32

Compressor and / or outdoor fan doesn’t operate.

Is there 208/230V AC
between

L1 - L2 on the

outdoor terminal block

?

No

Check the outdoor power supply
and connection of wiring.

Yes

Compressor
does not operate.

Yes

3minutes after the power
supply turns ON, is there
208/230V AC between
A1-A2 on the compressor
contactor(52C)?

Operate the unit in
COOL mode by pressing
the EMERGENCY
OPERATION switch.

Outdoor fan motor
does not operate.

No

Make the connection
of wiring correct.

Check the compressor.

Replace the compressor
contactor.

Turn ON the power supply.

Yes

Is there 208/230V AC
between 2/T1 on the
compressor contactor(52C)
and

L2 on the outdoor

terminal block?

Yes

Is there 208/230V AC
between CN730 1-3 on the
outdoor electronic control
P.C. board? w1

Replace the outdoor
electronic control
P.C. board.

No

Yes

No

Is there 208/230V AC
between 1/L1 on the
compressor contactor(52C)
and L2 on the outdoor
terminal block?

No

No

Make the connection
of wiring correct.

Yes

Yes

Yes

Is there 208/230V AC
between CN711 2-3 on
the outdoor electronic
control P.C. board? w1

Operate the unit in
COOL mode by pressing
the EMERGENCY
OPERATION switch.

No

Make the connection
of wiring correct.

Check the outdoor fan
motor. Refer to page 30.

Yes

No

No

Is there 5V DC between
J101 - J401 on the
outdoor electronic control
P.C. board? w1

+

w1 Refer to page 38.

Replace the outdoor
electronic control
P.C. board.

Is there 5V DC between
J101 - J401 on the
outdoor electronic control
P.C. board? w1

+

Is there 208/230V AC
between CN730 1-3 on the
outdoor electronic control
P.C. board? w1

Replace the outdoor
electronic control
P.C. board.

Replace the outdoor
electronic control
P.C. board.

D

Check of outdoor unit

33

Compressor and / or outdoor fan motor doesn’t stop.

After 30 seconds,
does compressor stop?

No

Yes

Is there 208/230V AC
between A1-A2 on the
compressor contactor(52C)?

Yes

1 Turn OFF the power supply.
2 After 30 seconds, turn ON the power supply again.
3 Operate the unit in COOL mode by pressing the

EMERGENCY OPERATION switch.
4 Operate the unit for 1 minute or more and stop it by
pressing the EMERGENCY OPERATION switch again.

Ok

No

After 30 seconds, does
outdoor fan motor stop?

Yes

Ok

No

Is there 208/230V AC
between 2/T1 on the
compressor contactor(52C)
and L2 on the outdoor
terminal block?

Yes

Replace the compressor
contactor(52C).

No

Make the connection
of wiring correct.

Replace the outdoor
electronic control
P.C. board.

Replace the outdoor
electronic control
P.C. board.

E

Check of outdoor unit

34

When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn’t operate.

FF

How to check mis-wiring

Start

Turn OFF the power supply.

Turn ON the power supply.

Rectify the wiring.

Correct the mis-wiring.

No

Is the power voltage to terminal blocks of
indoor/outdoor units normal?

Yes

Turn ON the EMERGENCY OPERATION switch.

After 3 minutes that power supply has
been turned on, does the compressor
start operating?

(any mode possible)

Yes

No

No

Is the terminal blocks11and33on the
indoor unit properly connected to their
counter parts on outdoor unit?

Yes

Turn OFF the power supply.
Check by using checking mode.

11

Disconnect indoor/outdoor wiring (at indoor terminal blocks 11and 33)

22

Short circuit between indoor terminal blocks 11and 33.

Turn ON the power supply.

33

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

44

Release the RESET button on the remote controller.

(After 3 seconds, LCD on the remote controller displays all signs.)

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

OK

Replace the indoor electronic
control P.C. board. ❈

Make sure the unit emits a beep tone.

No

Does the OPERATION INDICATOR
lamp on the indoor unit flash on?

Yes

Replace the outdoor electronic control P.C.board. ❈

Before the unit resumes normal operation.

•Release the checking mode by pressing the
RESET button on the remote controller, and then
send the unit signal to stop operation.

•Turn OFF the power supply to indoor/outdoor
units.

•Get indoor terminal blocks 11and 33opened, and
reconnect indoor/ outdoor wiring.

❈ Be sure to turn OFF the power supply to

[]

indoor/outdoor units in replacing P.C. board.

35

With remote controller set toward the indoor unit, press
the OPERATE/ STOP(ON/ OFF) button and confirm
one beep tone.

LEV operates in full-opening
direction.

Is LEV coil properly fixed to
the body?

Ok

Do you hear LEV "click,
click·······"?
Do you touch LEV and feel
it vibrate?

Does the resistance of LEV coil
have the characteristics?

No

Yes

Yes

Yes

No

LEV (CN724)

WHT–RED
RED–ORN
YLW–BRN

BRN–BLU

Resistance

30.3 " ~ 37.0 "

Characteristics of LEV coil

No

Properly fix LEV coil to
the body.

Replace the outdoor
electronic control P.C. board.

NOTE : After check of LEV, do the undermentioned operations.

1. Turn OFF the power supply of the unit and turn ON again.

2. Press the RESET button on the remote controller.

Replace the
LEV coil.

1 During pressing the OPERATION SELECT button

and the TOO COOL button on the remote controller,
press the RESET button.

2 First, release the RESET button.

(After 3 seconds, confirm all displays of the remote

controller.)

3 Then release the OPERATION SELECT button.

1 During pressing the OPERATION SELECT

button and the TOO COOL button on the

remote controller, press RESET button.

2 First, release the RESET button.

(After 3 seconds, confirm all displays of the
remote controller.)
3 Then release the OPERATION SELECT button.

AMPM

CLOCK

˚F

AMPM

When OPERATION INDICATOR lamp flashes 10-time.
Cooling doesn’t operate.

G

Check of LEV (Expansion valve)

When OPERATION INDICATOR lamp flashes 6-time.
Thermistors in the outdoor unit are abnormal.

H

Check of outdoor thermistor

w Disconnect the connectors CN662 from the outdoor electronic control P.C. board.

(Check the characteristics of each thermistor.)

Turn OFF the
power supply.

Discharge temperature
thermistor(RT62)

Measure
resistance
between CN 662
1 and 2.

Ambient temperature
thermistor(RT63)

Measure
resistance
between CN 662
3 and 4.

Does the resistance
of thermistor have
the characteristics
on page 38?

No

Replace the
thermistor.

36

Connect CN662.
Turn ON the power

Yes

supply and press
the EMERGENCY
OPERATION
switch.

Replace the outdoor

electronic control P.C.
board.

No

Does the unit operate
10 minutes or more?

Yes

Ok W1.

W1. It is thought defective contact of the connector.

TEST POINT DIAGRAM AND VOLTAGE

Indoor coil thermistor[RT12(main), RT13(sub)]

Room temperature thermistor (RT11)

32

F

50 68 86 104 122 140

MS24WN Indoor electronic control P.C. board

Fuse (F11)
250V AC 3.15A

R132

Varistor(NR11)

Fan motor power

}

supply

Power supply input

}

1 15V AC

5V DC

}

+

Room temperature
thermistor(RT11)

Indoor coil
thermistor(RT12(main))

Indoor coil
thermistor(RT13(sub))

Receiver P.C. board

Auto restart function
Solder the Jumper wire or the
Resistor 220Ω to the JR07.
(Refer to page 26.)

+

}

12V DC

Emergency operation
switch

Timer short mode point
(JPS, JPG)
(Refer to page 25.)

37

MU24WN

Temperature(-F)

Discharge temperature thermistor(RT62)

Resistance(k")

32 50 68 86 104122140158176194 212230248

0

100

200

300

400

500

600

700

800

900

Ambient temperature thermistor (RT63)

0

10

20

30

40

50

60

70

80

90

100

Resistance(k")

-4 14 32 50 68 86 104

Temperature(-F)

Outdoor electronic control P.C. board

CN662 1-2
Discharge
temperature
thermistor
(RT62)

(Refer to page 36.)

J101

+

}

5V

DC

J401

(Refer to
page 33.)

CN662 3-4
Ambient
temperature
thermistor
(RT63)

LEV
connector
(CN724)

(Refer to page 36.)

38

Fan motor
connector
(CN711)

+

12V DC

}

Fuse (F61)

3.15A / 250V

CN7301-3

}

208/230V AC

(Refer to
page 33.)

RELAY OPERATION
MS24WN

COMPRESSOR CONTACTOR

• EACH MODE

MODE

COOL & COOL mode
of I FEEL CONTROL

DRY & DRY mode
of I FEEL CONTROL

FAN

NOTE : Once the compressor is OFF, “3-minute time delay circuit” works at next start-up.

• COIL FROST PREVENTION

THERMOSTAT

ON

OFF

ON

OFF

OFF

52C CONTACTOR INDOOR FAN SPEED

ON

AUTO or set speed

OFF

OFF for 2 min.

after unit starts operation

Repeat of 8 min. ON/ 3min.
OFF operation or 2 min.
ON/3 min. OFF operation

Repeat of 4 min. OFF/
1 min. ON operation

OFF

AUTO or set speed

AUTO or set speed links with
52C CONTACTOR

AUTO or set speed

MODE THERMOSTAT 52C CONTACTOR INDOOR FAN SPEED

COOL & COOL mode
of I FEEL CONTROL

OFF for 5 min.

AUTO or set speed

After that, OFF is

ON

DRY & DRY mode
of I FEEL CONTROL

prolonged until
indoor coil thermistor
reads termination
temperature.

AUTO or set speed

39

11

(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector is a terminal

with lock mechanism.

1Slide the sleeve.
2Pull the terminal while

pushing the locking
lever.

1Hold the sleeve, and
pull out the terminal
slowly.

In case of terminal with lock mechanism, detach the terminal as shown below.
There are two types ( Refer to (1) and (2)) of the terminal with lock mechanism.
The terminal with no lock mechanism can be removed by pulling it out.
Check the shape of the terminal and work.

<"Terminal with lock mechanism" Detaching points>

Connector

Sleeve

Locking lever

DISASSEMBLY INSTRUCTIONS

11-1. MS24WN

INDOOR UNIT

OPERATING PROCEDURE

1. Removing the front panel

(1) Remove the screw caps of the front panel.

Remove the screws.

(2) Pull the panel down to your side slightly and unhook the

catches at the top.

2. Removing the electronic control P.C. board, the receiver
P.C. board and the display P.C. board

NOTE : In case of removing only indoor electronic control

P.C. board work (2) and (3) are not necessary.
(1) Remove the front panel. (Refer to 1.)
(2) Remove the R.L holder from the bottom of electrical box.
(3) Open the R.L holder, remove the receiver P.C. board and

the display P.C. board.

(4) Remove the screw of the electrical cover and the electrical

cover.
(5) Pull out indoor electronic control P.C. board slightly.
(6) Disconnect all the connectors on the electronic control P.C.

board.
(7) Remove the electronic control P.C. board.

Photo 1

Photo 2

R.L

Screw of

holder

the corner
box

PHOTOS

Front panel

Screws

Indoor
electronic
control
P.C.board

Screw of
the electrical
cover

Receiver
P.C.
board

40

OPERATING PROCEDURE

PHOTOS

3. Removing the electrical box

(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Disconnect the connector of the indoor coil

thermistor (CN112), the fan motor connector (CN211 and
CN121) and the vane motor connector (CN151) on the

electronic control P.C. board.
(4) Remove the screw of ground wire.
(5) Remove the fan motor lead wire, indoor coil thermistor and

ground wire from the electrical box.
(6) Remove the lead wire of vane motor from the bottom of

electrical box.
(7) Remove the screw of corner box and corner box. (Photo 2)
(8) Remove the screw of conduit cover and conduit cover.
(9) Remove the screws fixing the conduit plate.
(

10

) Pull out the conduit plate and the indoor/ outdoor unit con-

necting wire.
(

11

) Remove the lock nut from the connector of indoor/ outdoor

connecting wire.

12

) Remove the screw fixing the electrical box, remove the

(

electrical box.

4. Removing the vane motor

(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Remove the lead wire of

vane motor. (Refer to 3.)
(4) Remove the R.L. holder.
(5) Pull out the drain hose

from the nozzle assem-

bly, remove the nozzle

assembly.
(6) Remove the screws of the

vane motor, disconnect

the connector.
(7) Remove the vane motor.

Photo 5

Screws of the
vane motor

Photo 3

Screws of
the conduit
plate

Photo 4

Screws of the ground wire

Screw of the
conduit cover

Vane motors

Fan motor
connectors

Indoor coil
thermistor
connector

Vane motor
connector

Screw of the
electrical box

Screws
of the
vane
motor

Vane motor

5. Removing the line flow fan and the indoor fan motor

(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical box. (Refer to 3.)
(3) Pull out the drain hose from the nozzle assembly, remove

the nozzle assembly.
(4) Remove the water cut.
(5) Slide the hole cover, remove the hole cover.
(6) Remove the hexagon socket set screw from the line flow

fan.
(7) Remove the screws fixing the fan motor, remove the fan

motor. (Be careful not to drop the fan motor because it is

heavy.)
(8) Remove the screws fixing the left

side of the heat exchanger.

(9) Lift the left side of the heat

exchanger.

10

) Remove the line flow fan.

(

Hole
cover

Photo 8

Photo 6

Screws fix­ing the left
side of the
heat
exchanger

Photo 7

Indoor
coil
thermistor

Water cut

Screws
fixing
the fan
motor

41

11-2. MU24WN

OUTDOOR UNIT

OPERATING PROCEDURE PHOTOS

1. Removing the cabinet

(1) Remove the screws of the top panel and the top panel.
(2) Remove the screw of the service panel. To remove the

service panel, pull it down toward you and unhook the
catches on the both sides.

(3) Remove the screw of the cover panel. To remove the

cover panel.

(4) Remove the screws of the cabinet.

Open the cabinet to a 45-degree angle. Then lift it and
unhook the catches to remove.

Photo 2

Discharge
pipe

Suction
pipe

Screws of the cabinet

2. Removing the outdoor electronic control P.C. board

(1) Remove the top panel, the service panel and the cover

panel.

(2) Disconnect all the connectors and the terminals on the

outdoor electronic control P.C. board.

(3) Remove the outdoor electronic control P.C. board.

Photo 1

Screws of the top panel

Photo 3

Outdoor
electronic
control P.C.
board

Terminal
blocks

Cover panel

Screw of the
service panel

Relay
panel

Fan motor
connector

Compressor
contactor

3. Removing the propeller and the outdoor fan motor

(1) Remove the cabinet. (Refer to 1.)
(2) Remove the propeller nut and the propeller.

NOTE:Loose the propeller in the rotating direction for

removal.
When attaching the propeller, align the mark on the
propeller and the motor shaft cut section.
Set the propeller in position by using the cut on the
shaft and the mark on the propeller.

(3) Remove the lead clamps and disconnect the outdoor

fan motor connector. (Photo 3)

(4) Remove the screws of the outdoor fan motor and the

outdoor fan motor.

42

Photo 4

Screw of
the side
panel

Propeller

Propeller
nut
Screw of
the side
panel

Screws
of the
fan motor

Screws of the
motor support

Lead
clamps

Screw of the
separator
support plate

Screws of
the valve
bed

Screw of the separator

OPERATING PROCEDURE

PHOTOS

4. Removing the heat exchanger and compressor

(1) Remove the screws of the rear panel. Remove the

screws of the valve bed and the valve bed.
(The valve bed is fixed by the catches on the right and
left sides. Lift it to remove.)
Open the rear panel to the rear to remove.

NOTE :

All panels are fixed by catches, and must be removed
by up and down.

(2) Remove the screws of the side panel and the side

panel.
(Photo 4)

(3) Remove the screws of the rear guard and the rear

guard.

(4) Remove the screws of the separator support plate and

the separator support plate. (Photo 4)

(5) Remove the screws of the motor support and the motor

support. (Photo 4)
(6) Remove the relay panel. (Photo 3)
(7) Remove the fan motor lead wire from lead clamps.

(Photo 4)
(8) Remove the soundproof felt.
(9) Remove the screws of the separator and the separator.
(10)

Recover gas from the refrigerant circuit.

(11)

Remove the heat exchanger.

Detach the welded part of pipe.

(12)

Remove the nuts of the compressor and the compressor.
Detach the welded part of the suction pipe and the
discharge pipe. (Photo 2)

Photo 5

Screws of the
rear panel

Photo 6

Accumulator

Screws of the
rear guard

Screws of the
rear guard

Heat exchanger

43

Photo 7

Screw of the
separator

Stop valve

Compressor

Soundproof
felt

12

MS24WN

E02 527 970
E02 527 234
E02 527 000
E02 408 142
E02 527 067
E02 527 010
E02 527 100
E02 527 975
E02 530 007

INSTALLATION PLATE
BOX (W

)

FRONT PANEL ASSEMBLY (W

)

CATCH
SCREW CAP (W

)

GRILLE (W

)

AIR FILTER
CORNER BOX RIGHT
LAMP PANEL

Symbol

in Wiring

Diagram

Q'ty/unit

Including No.4,5,6

4PCS/ SET
3PCS/ SET

RemarksPart No.

NO.

Part Name

1
2
3
4
5
6
7
8
9

1
1
1
4
3
1
2
1
1

(W)

E02 527 620
E02 527 666
E02 527 667

INDOOR HEAT EXCHANGER
UNION (GAS

)

UNION (LIQUID

)

{5/8
{3/8

10
11
12

1
1
1

PARTS LIST

MS24WN (W)
12-1. INDOOR UNIT STRUCTURAL PARTS

1
2
3

12-2. INDOOR UNIT HEAT

EXCHANGER

10

4

CATCH

5

SCREW
CAP

6

7

12-1. INDOOR UNIT STRUCTURAL PARTS

Part number that is circled is not shown in the illustration.

8

Optional
parts
(See
back
cover.)

11

12

12-2. INDOOR UNIT HEAT EXCHANGER

44

MS24WN (W)

23
24

E02 784 426
E02 527 083

REMOTE CONTROLLER
REMOTE CONTROLLER HOLDER

1
1

12-3. INDOOR UNIT FUNCTIONAL PARTS AND

ELECTRICAL PARTS

1

20

12-4. ACCESSORY AND

REMOTE CONTROLLER

19

23 24

2
3

SLEEVE
BEARING

4

ROOM

18

12

11

TEMPERATURE
THERMISTOR

5
6

14

13

10

7

FUSE

8

VARISTOR

9

15

16

17

12-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS

Part numbers that are circled are not shown in the illustration.

Q'ty/unit

MS24WN

(W)

1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1

NO.

Part No.

1

E02 527 302
E02 408 509

2

E02 001 504

3

E02 408 702

4

E02 527 235

5

E02 527 040

6

E02 527 041

7

E02 784 382

8

E02 784 385

9

E02 527 034

10

E02 784 300

11

E02 448 303

12

E02 408 303

13

E02 527 333

14
15

E02 528 329

16

E02 527 468

17

E02 784 452

18

E02 527 308

19

E02 545 375

20

E02 527 307

21

E02 528 034

22

E02 529 034

Part Name

LINE FLOW FAN
BEARING MOUNT
SLEEVE BEARING
DRAIN HOSE
NOZZLE ASSEMBL Y
VANE UPPER (W
VANE LOWER (W
FUSE
VARISTOR
VANE CRANK SET
INDOOR FAN MOTOR ASSEMBLY
VANE MOTOR (VERTICAL
VANE MOTOR (HORIZONTAL
MOTOR BAND
DISPLAY P.C. BOARD
RECEIVER P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ROOM TEMPERATURE THERMISTOR
TERMINAL BLOCK
INDOOR COIL THERMISTOR
VANE MOTOR SUPPORT SET(RIGHT
VANE MOTOR SUPPORT SET(LEFT

)

)

)

)

Symbol

in Wiring

Diagram

F11

NR11

MF
MV2
MV1

RT11

TB

RT12, RT13

)

)

Remarks

3.15A

RC4W33 ­Including RUBBER MOUNT

RIGHT & LEFT
UP & DOWN

AUTO RESTART
Including No.16

12-4. ACCESSORY AND REMOTE CONTROLLER

45

MU24WN
12-5. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS

AND FUNCTIONAL PARTS

31

1

2

3

4

5

6

7

30

29

27

26

9

28

8

9

10

11

12

25

19

A

B

16

18

17

21

22

24

23

2

13

14

20

15

46

MU24WN

MU24WN

E02 813 297
E02 528 309
E02 527 630
E02 784 301
E02 214 501
E07 070 508
E02 813 290
E02 813 232
E02 819 009
E02 784 521
E02 528 493
E02 527 640
E02 527 506
E02 784 900
E02 527 662
E02 527 661
E07 001 641
E07 012 641
E02 474 642
E02 813 245
E02 813 006
E02 480 374
E02 481 374
E02 784 351
E02 784 340
E02 544 353
E02 128 383
E02 784 451
E02 813 522
E02 813 523
E02 814 249
E02 527 515
E02 784 382
E02 262 936
E02 527 936
E02 784 936

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18
19
20
21

22
23

24
25
26
27
28
29
30
31
32

33
34

TOP PANEL
THERMISTOR
OUTDOOR HEAT EXCHANGER
OUTDOOR FAN MOTOR
PROPELLER
PROPELLER NUT
BASE
CABINET
HANDLE
FAN GUARD
EXPANSION VALVE COIL
EXPANSION VALVE
COMPRESSOR RUBBER SET
COMPRESSOR
STOP VALVE (LIQUID

)

STOP VALVE (GAS

)
SERVICE PORT
SERVICE PORT

FUSIBLE PLUG
SERVICE PANEL
COVER PANEL
TERMINAL BLOCK
TERMINAL BLOCK
OUTDOOR FAN CAPACITOR
COMPRESSOR CONTACTOR
COMPRESSOR CAPACITOR
SURGE ABSORBER
OUTDOOR ELECTRONIC CONTROL P.C. BOARD
REAR PANEL
REAR GUARD
SIDE PANEL
MOTOR SUPPORT
FUSE
CAPILLARY TUBE
CAPILLARY TUBE
CAPILLARY TUBE (TAPER PIPE)

Symbol

in Wiring

Diagram

Q'ty/unit

NEW WHITE(Brighter)

DISCHARGE, AMBIENT

RA6N66-

NEW WHITE(Brighter)
NEW WHITE(Brighter)
NEW WHITE(Brighter)
NEW WHITE(Brighter)

4RUBBERS/SET
PH33NPBT

{3/8
{5/8

NEW WHITE(Brighter)
NEW WHITE(Brighter)
4P (FIGURE A

)

4P (FIGURE B

)

5.0+/440VAC

35+/370VAC

NEW WHITE(Brighter)
NEW WHITE(Brighter)
NEW WHITE(Brighter)

250V/3.15A

{0.16✕{0.09✕7-7/8
{0.16✕{0.09✕3-15/16
{0.14✕{0.09✕1-31/32

Remarks

Part No.

NO.

Part Name

RT62, RT63

MF

LEV

MC

TB1
TB2

C2

52C

C1

DSAR

F61

1
1
1
1
1
1
1
1
3
1
1
1
4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1

12-5. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS

AND FUNCTIONAL PARTS

Part numbers that are circled are not shown in the illustration.

47

13

OPTIONAL PARTS

13-1. REFRIGERANT PIPES

The air conditioner has flared connections its on indoor and outdoor sides.
Please use the optional extension pipe as follows.

Part No.Model

MAC-860PI

MAC-861PI
MS24WN
MU24WN

MAC-862PI

MAC-863PI

MAC-864PI

13-2. AIR CLEANING FILTER

● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity.

● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible.

● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet.

● DO NOT reuse AIR CLEANING FILTER even if it is washed.

● DO NOT remove or attach AIR CLEANING FILTER during unit operation.

Pipe length

10ft.
16ft.
23ft.
33ft.
49ft.

Cross-

section

,,,

Outside

diameter

5/8 3/8 0.0285

Pipe size

A-Gas(in.)

Wall

thickness

B-Liquid(in.)

Outside

diameter

thickness

Wall

0.0315

Insulation

(in.)

C 1-7/32
D 1-1/16

Additional

refrigerant

charge

R22(oz.)

0

1.3

3.9

Model

MS24WN

MAC-1700FT

13-3. DEODORIZING FILTER

● DEODORIZING FILTER removes ammonia and hydrogen sulphide emitted from tobacco, and odor of pets.

● Clean DEODORIZING FILTER every two weeks. If the filter is particularly dirty, clean the filter more often.

● For cleaning, soak the filter in warm water for a while, and then wash and rinse it. Dry the filter in the shade

thoroughly.

● When the filter color is still dark even after cleaning, replace the filter with a new one.
Replace the filter at least once a year.

Model

MS24WN

● DEODORIZING FILTER and AIR CLEANING FILTER
can be attached on either side.

MAC-2200DF

Part No.

Air cleanig filter (White bellow type)

Part No.

Deodorizing filter (Gray sponge type)

.

CC

Copyright 2003 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD.
Distributed in Jan. 2004. No. OB311 REVISED EDITION-A 6
Distributed in Mar. 2003. No. OB311 17

New publication, effective Jan. 2004
Specifications subject to change without notice.

3400 Lawrenceville Suwanee Road ● Suwanee, Georgia 30024

Toll Free: 800-433-4822 ● Toll Free Fax: [phone]

www.mrslim.com

Specifications are subject to change without notice.