Mitsubishi Electric MS-18NN, MU-18NN, MS-24NN, MU-24NN, MS-18NN-S1 Service Manual

SPLIT-TYPE, AIR CONDITIONERS

SERVICE MANUAL

Wireless type
Models

No. OB188

MS-18NN ­MS-24NN -

(WH)

(WH)

· MU-18NN -

· MU-24NN -

CONTENTS

1. TECHNICAL CHANGES ····································2

2. PART NAMES AND FUNCTIONS ······················3

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

4. OUTLINES AND DIMENSIONS·························7

5. WIRING DIAGRAM ············································8

6. REFRIGERANT SYSTEM DIAGRAM··············10

7. PERFORMANCE CURVES······························13

8. MICROPROCESSOR CONTROL ····················15

9. SERVICE FUNCTIONS ····································23

10. TROUBLESHOOTING······································24

11. DISASSEMBLY INSTRUCTIONS ·····················30

12. PARTS LIST······················································34

13. OPTIONAL PARTS···········································38

S1S1

S1S1

1

TECHNICAL CHANGES

MS-18JN- ➔ MS-18NN-

1. Indoor unit model and outdoor unit model have changed.

2. Indoor fan motor has changed. (S4N-24B-EA ➔ RA4N30-AA)

3. Outdoor fan motor has changed. (S6M-50F-CB ➔ RA6V50-OD)

4. Compressor has changed. (NHJ-36NBD ➔ NH-28NCDT)

5. The remote controller has changed.

6. Microprocessor control has changed.

MS-24JN- ➔ MS-24NN-

1. Indoor unit model and outdoor unit model have changed.

2. Indoor fan motor has changed. (S4N-26B-BA ➔ RA4N30-AA)

3. Outdoor fan motor has changed. (S6N-60F-AB ➔ RA6V60-AB)

4. Compressor has changed. (NHJ-38NBD ➔ NH-38NBDT)

5. The remote controller has changed.

6. Microprocessor control has changed.

S1 S1

S1 S1

2

2

PART NAMES AND FUNCTIONS

INDOOR UNIT

MS-18NN-

MS-24NN-

,

S1S1

OUTDOOR UNIT

MU-18NN-

MU-24NN-

,

S1S1

3

REMOTE CONTROLLER

MS-18NN-

MS-24NN-

,

S1S1

4

3

Model MS-18NN-

Function Cooling

Power supply Single phase 220V 60Hz

S1

W 4,200

kcal/h 3,600
Electrical Current A 10.7
data Input W 2,300

Capacities

Capacity kW 5.1

Capacities Dehumidification

R/h

2.5

Air flow

m3/h

780

Current A 8.9
Input W 1,910
Power factor % 98
Starting current A 55
Compressor motor current A 8.15
Fan motor current A 0.75

Coefficient of performance 2.67

Electrical
data

Model — NH-28NCDT
Output W 1,200

Width

mm<in.>

1,015 <40>

Indoor unit Height

mm<in.>

320 <12-9/16>

Depth

mm<in.>

190 <7-1/2>

Width

mm<in.>

850 <33-1/2>

Outdoor unit Height

mm<in.>

605 <23-13/16>

Depth

mm<in.>

290 <11-3/8>
Indoor unit kg<lb> 14 <31>
Outdoor unit kg<lb> 55 <121>
Air direction — 5

Indoor

Fan speed unit

(Hi) Outdoor

unit

Indoor

Fan speed unit

regulator Outdoor

unit

Refrigerant filling

capacity (R-22)

Compressor

Dimensions

Weight

Special
remarks

kg<lb>

1.65 <3.63>

rpm

rpm

1,180

86514

SPECIFICATION

SSA 385/386*

JIS

Rating Conditions : SSA 385/386-Indoor DB29°C WB19°C,Outdoor DB46°C WB24°C
Note ✽ SSA 385/386 can be applied only to Saudi Arabia.

JIS-Indoor DB27°C WB19°C,Outdoor DB35°C WB24°C

5

Model MS-24NN-

Function Cooling

Power supply Single phase 220V 60Hz

S1

W 5,500

kcal/h 4,700
Electrical Current A 16.1
data Input W 3,500

Capacities

Capacity kW 6.6

Capacities Dehumidification

R/h

3.5

Air flow

m3/h

840

Current A 13.5
Input W 2,930
Power factor % 99
Starting current A 56
Compressor motor current A 12.58
Fan motor current A 0.92

Coefficient of performance 2.25

Electrical
data

Model — NH-38NBDT
Output W 1,700

Width mm<in.> 1,015 <40>

Indoor unit Height mm<in.> 320 <12-9/16>

Depth mm<in.> 190 <7-1/2>
Width mm<in.> 850 <33-1/2>

Outdoor unit Height mm<in.> 605 <23-13/16>

Depth mm<in.> 290 <11-3/8>
Indoor unit kg<lb> 14 <31>
Outdoor unit kg<lb> 61 <135>
Air direction — 5

Indoor
Fan speed unit
(Hi) Outdoor

unit

Indoor
Fan speed unit
regulator Outdoor

unit
Refrigerant filling
capacity (R-22)

Compressor

Dimensions

Weight

Special
remarks

kg<lb>

2.15 <4.73>

rpm

rpm

1,260

93042

SSA 385/386*

JIS

Rating Conditions : SSA 385/386

JIS-Indoor DB27°C WB19°C,Outdoor DB35°C WB24°C

Note ✽ SSA 385/386 can be applied only to Saudi Arabia.

6

-

Indoor DB29°C WB19°C,Outdoor DB46°C WB24°C

4

OUTLINES AND DIMENSIONS

INDOOR UNIT

MS-18NN­MS-24NN-

150

S1

S1

4holes

✕20

11

648

217

40

60

Indoor unit

320

50

MU-18NN­MU-24NN-

450

450

438

Installation plate

1015

775

56

S1

S1

160

352

17.5

20

274

284

297

3

Wall hole [75

190

Power supply cord
Lead to right 2m
Lead to left 1m

Air in

Air out

190 5

Installation plate
Liquid line [8-0.5m
Gas line [12-0.43m
Installation [50 O.D
[28 I.D

Drain hose [16
Insulation [28

OUTDOOR UNIT

35

248

Air in

Drainage
3holes [16.2

605

292

20

50

350

Air out

183

500
850

20

74

157

290

30

100

310

If both sides or back
side is vacant. only

345

to be free 50cm in
front of a unit.

30

161

Service panel

Liquid refrigerant
pipe joint
Refrigerant pipe (flared)

o

[6.35(MS-18)
[9.52(MS-24)

o

35

Gas refrigerant
pipe joint
Refrigerant pipe (flared)
[15.88

If a front side

or both side is vacant,

an upper side of a

unit has only to be vacant 10cm.

7

5

TRANS

NR11

HIC1

IC141

1

DSAR

GRN/YLW

WHT

WHT

LD1

REMOTE
CONTROLLER

3

3

BLU
BLU

BLU

DISPLAY
P.C.BOARD

CN

102

3

WHT

F12

2
1

CN201

1

3

3

4

F11

5

MV

151

CN

111

CN

RT11

BRN
YLW

RED

GRY
WHT

BLK

RECEIVER
P.C.BOARD

BLU

112

CN

121

CN

RT12

2

101

CN

52C

CN211

C11

1

2

4

ELECTRONIC CONTROL P.C BOARD

TB

GRN/YLW

N

3

RED

TO OUTDOOR
UNIT
CONNECTING

MF

POWER SUPPLY
CORD
1[220V
60Hz

SYMBOL NAME SYMBOL NAME SYMBOL NAME

C11 INDOOR FAN MF INDOOR FAN MOTOR TB TERMINAL BLOCK

DSAR SURGE ABSORBER MV VANE MOTOR IC141 HYBRID IC

F11 FUSE(3.15A) 52C COMPRESSOR CONTACTOR NR11 VARISTOR
F12 FUSE(93°C) RT11 ROOM TEMPERATURE THERMISTOR

HIC1 DC/DC CONVERTER RT12 INDOOR COIL THERMISTOR

WIRING DIAGRAM

INDOOR UNIT

MS-18NN-

TO OUTDOOR
UNIT
CONNECTING

POWER SUPPLY
CORD
1[220V
60Hz

MS-24NN-

S1

TB

L

❈

BRN

2

❈

N

❈

BLU

GRN/YLW

S1

❈

MODEL MS-18NN - WIRING DIAGRAM

S1

BRN

❈

4

52C

❈

3

WHT

BLU

F12

BLU
BLU

2
1

BLU

CN201

3
1

BRN

LD1

CN

CN

CN
101

GRN/YLW

DSAR

3

RECEIVER
P.C.BOARD

REMOTE
CONTROLLER

MODEL MS-24NN - WIRING DIAGRAM

102

3

DISPLAY
P.C.BOARD

151

MV

S1

ELECTRONIC CONTROL P.C BOARD

5

HIC1

TRANS

F11

IC141

NR11

CN
112

3

CN
121

CN211

C11

4
2
1

CN
111

BRN
YLW
GRY
WHT
RED
BLK

RT11

RT12

MF

❈

❈

❈

❈

NOTES : 1.For the outdoor electric wiring refer to the outdoor unit electric wiring diagram for servicing.

8

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

3.Symbols below indicate.

4.”❈”shows the terminals with a lock mechanism, so they cannot be removed when you pull the lead wire.
Be sure to pull the wire by pushing the locking lever (projected part) of the terminal with a finger.

/ : Terminal block : Connector

11

Side the sleeve.

22

Pull the wire while
pushing the locking lever.

OUTDOOR UNIT

SYMBOL NAME SYMBOL NAME SYMBOL NAME

COMPRESSOR OUTDOOR FAN MOTOR THERMAL REED
CAPACITOR (INNER THERMOSTAT) SWITCH
OUTDOOR FAN
CAPACITOR
COMPRESSOR FAN MOTOR SURGE
(INNER THERMOSTAT) RELAY ABSORBER

C1MF26F1C2TB

52CMCX1

CR

TERMINAL BLOCK

CONTACTOR

SYMBOL NAME SYMBOL NAME

COMPRESSOR FAN MOTOR
CAPACITOR (INNER THERMOSTAT)
FAN MOTOR
CAPACITOR
COMPRESSOR
(INNER THERMOSTAT)

C1MFC2TBMC

TERMINAL BLOCK

MU-18NN-

S1

MODEL MU-18NN - WIRING DIAGRAM

S1

TB

GRN/YLW

TO INDOOR
UNIT
CONNECTING

MU-24NN-

TO INDOOR
UNIT
CONNECTING

S1

TB

2

N

3

❈

2

N

❈

MODEL MU-24NN - WIRING DIAGRAM

WHT

2

S1

52C

1

BLK

WHT

52C

YLW

❈

YLW

4

6

3

52C

5

C2

❈

BLK
RED

❈

GRN/YLW

GRY
GRY

b
a

RED

52C

CR

5

GRY

78

X1

3

6

X1

1

26F1

BLK

RED
ORN
WHT
BLK
YLW

1
2
3
4
5
6

WHT

C1

C2

RED
ORN
WHT
BLK
YLW

RED

BLK

MF

S

BLK
WHT
ORN
RED

MC

BLK

4

WHT

3

ORN

2

RED

1

C

MC

RED

R

MF

C

RS

BLK

C1

NOTES : 1.Use copper conductors only. (For field wiring)

2.”❈”shows the terminals with a lock mechanism.so they cannot
be removed when you pull the lead wire.
Be sure to pull the wire by pushing the locking
lever (projected part) of the terminal with a finger.

3.Symbols below indicate.
/ : Terminal block : Connector

11

Side the sleeve.

22

Pull the wire while
pushing the locking lever.

9

6

REFRIGERANT SYSTEM DIAGRAM

Umit:mm

MS-18NN -

INDOOR UNIT

Indoor heat
exchanger

RT11
Room
temperature
thermistor

S1

Indoor coil
thermistor
RT12

Refrigerant pipe
(Option) [15.88
(with heat insulator)

Flared
connector

Flared
connector

Refrigerant pipe
(Option)[6.35
(with heat insulator)

Stop valve
(With service port)

Stop Valve

ACCUMULATOR

DISCHARGE
PRESSURE

[

1.4 650

[

2.0 700

REGULATOR

Compressor

STRAINER

MU-18NN -

S1

OUTDOOR UNIT

Outdoor
heat
exchanger

Flow of refrigerant

MS-24NN -

INDOOR UNIT

Indoor heat
exchanger

RT11
Room
temperature
thermistor

10

S1

Indoor coil
thermistor
RT12

Refrigerant pipe
(Option) 15.88
(with heat insulator)

Refrigerant pipe
(Option) 9.52
(with heat insulator)

[

Flared
connector

Flared
connector

[

Stop valve
(With service port)

Stop Valve

ACCUMULATOR

[

1.6 350

[

2.0 600

Compressor

DISCHARGE
PRESSURE
REGULATOR

[

2.0 100
STRAINER

Umit:mm

MU-24NN -

S1

OUTDOOR UNIT

Outdoor
heat
exchanger

Flow of refrigerant

Model Outdoor unit precharged Refrigerant piping length (one way)

(up to 7m) 7m 10m 15m

MS-18NN - 1650

MS-24NN - 2150

0

45

120

S1

S1

Additional piping

Model Max. length : m

A Gas Liquid Indoor unit Outdoor unit

MS-18NN - 15

[6.35

MS-24NN -

[9.52

15

[15.88

0.43

0

S1

S1

Piping size O.D : mm

Length of connecting pipe : m

MAX. REFRIGERANT PIPING LENGTH

MAX. HEIGHT DIFFERENCE

ADDITIONAL REFRIGERANT CHARGE(R-22 : g)

Note : Calculation : Xg=15g/m✕(A-7)m

11

EVACUATION PROCEDURES

Connect the refrigerant pipes (both the liquid and gas pipes)
between the indoor and the outdoor units.

Remove the service port cap of the stop valve on the side of the outdoor unit gas pipe (The stop valve will not
work in it initial state fresh out of the factory (totally closed with cap on).)

Connect the gage manifold valve and the vacuum pump to

the service port of the stop valve on the gas pipe side of the
outdoor unit.

Run the vacuum pump(Vacuumize for more than 15 minutes.)
and at this time confirm that the pressure gage shows -0.1
Mpa ( -76cm Hg).

Check the vacuum with the gage manifold valve, then close

the gage manifold valve, and stop the vacuum pump.

Leave it as is for one or two minutes. Make sure the pointer

gage manifold valve remains in the same position.

Remove the gage manifold valve quickly from the service port of the stop valve.

After refrigerant pipes are connected and evacuated, fully open all stop valves on gas and liquid pipe sides.
Operating without fully opening lowers the performance and causes trouble.

12

Pipe length :

7m maximum
No gas charge
is needed

Tighten the cap to the service port to obtain the initial status

Retighten the cap

Leak test

Pipe length

exceeding 7m
Charge the prescribed
amount of gas

7

PERFORMANCE CURVES

MS-18NN- MS-24NN-

The standard data contained in these specifications apply only to the operation of the air conditioner under normal conditions.
Since operating conditions vary according to the areas where these units are installed. The following information has been pro­vided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.

S1 S1

(1) GUARANTEED VOLTAGE

Rated voltage : ±10% (198 ~ 242V ) 60Hz

(2) AIR FLOW

Air flow should be set at MAX.

(3) MAIN READINGS

(1) Indoor intake air wet-bulb temperature : °CWB
(2) Indoor discharge air wet-bulb temperature : °CWB
(3) Outdoor intake air dry-bulb temperature : °CDB
(4) Total input: W

Indoor air wet-bulb temperature difference on the left side of the chart on next page shows the difference between the
indoor intake air wet-bulb temperature and the indoor discharge air wet-bulb temperature for your reference at service.

How to measure the indoor air wet-bulb temperature difference

1. Attach at least 2 sets of wet-and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets
of wet-and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air
speed is high.

2. Attach at least 2 sets of dry-bulb thermometers to the outdoor air intake.
Cover the thermometers to prevent direct rays of the sun.

3. Check that the air filter is cleaned.

4. Open windows and doors of room.

5. Press the EMERGENCY ON/OFF button to start the EMERGENCY operation.

6. When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.

7. 10 minutes later, measure temperature again and check that the temperature does not change.

}

Cooling

INDOOR UNIT

OUTDOOR UNIT

13

OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation

① Both indoor and outdoor unit are under the same temperature/humidity condition.

Dry-bulb temperature(;)

20
25
30 70

➁ Air flow should be set at MAX.

Relative humidity(%)

MU-18NN -

Outdoor low pressure(kg/cm2)Outdoor unit current(A)

Ambient temperature(˚C)
Ambient humidity(%)

MU-18NN -

50
60

S1

Outdoor low pressure(kg/cm2)

S1

MU-24NN -

Ambient temperature(˚C)
Ambient humidity(%)

MU-24NN -

S1

S1

Ambient temperature(˚C)
Ambient humidity(%)

14

Outdoor unit current(A)

Ambient temperature(˚C)
Ambient humidity(%)

8

Operation Indicator

Initial room temperature mode

COOL mode of

I FEEL CONTROL

DRY mode of

"I FEEL CONTROL"

more than 25°C

13°C to 25°C

MICROPROCESSOR CONTROL

Wireless remote controller

INDOOR UNIT DISPLAY SECTION

MS-18NN ­MS-24NN -

Once the controls are set, the same operation mode can be
repeated by simply turning the OPERATE/STOP 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.

1. “I FEEL CONTROL”OPERATION

S1

S1

(1) Press OPERATE/STOP button on the remote con-

troller. OPERATION INDICATOR LAMP of the
indoor unit will turn on with a beep tone.

(2) Press OPERATION SELECT button to set “I FEEL

CONTROL” Then a beep tone is heard.

(3) The operation mode is determined by the initial

room temperature at start-up of the operation.

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

● Under the ON-TIMER operation, the mode is determined
according to the room temperature as the operation
starts.

● When the system is stopped with the
OPERATE/STOP button 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.

Example

Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode.

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

Example

Previous operation
COOL mode of “I
FEEL CONTROL”
or COOL mode.

Restart
COOL mode of “I
FEEL CONTROL”

Restart
COOL or DRY mode of
“I FEEL CONTROL” that
determined by initial
room temperature start­up of the operation.

15

Model Initial room temperature Initial set temperature

26°C or more 24°C

Initial room temperature
minus 2°C

DRY mode of Initial room temperature

"I FELL CONTROL" minus 2°C

COOL mode of

"I FEEL CONTROL"

26°C or less

13°C to 25°C

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

❈ 1

❈1 After the system restarts by the remote controller, the system operates with the previous set temperature regardless of

the initial set temperature.
The set temperature is calculated by the previous set temperature.

(5) TEMPERATURES buttons

In “I FEEL CONTROL” mode, set temperature is decided by the microprocessor based on the room temperature.
In addition, set temperature is controlled by TOO WARM or TOO COOL buttons when you feel too cool or too warm.
Pressing the TOO WARM or TOO COOL button 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
cold. 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.

▲ TOO
COOL… To raise the set temperature 1~2 degrees(°C)

▼ TOO
WARM … To lower the set temperature 1~2 degrees(°C)

16

— COOL mode of “I FEEL CONTROL” —

ON

Compressor and

OFF

ON

OFF

outdoor fan motor

Indoor fan motor

ON

Run continuously in cooling mode

NOTE : Coil frost prevention during COOL mode of “I FEEL CONTROL”

There are two types of controls in coil frost prevention.

① Temperature control

When the indoor coil thermistor RT12 reads -1°C or below, the coil frost prevention mode starts immediately.

However the coil frost prevention will not work for 5 minutes after the compressor starts.
The compressor stops and the indoor fan operates at the set speed for 5 minutes.
After that, if RT12 still reads below -1°C this mode prolonged until the RT12 reads over -1°C .

② Time control

When the three conditions below 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 Lo or Me.
c. Room temperature is below 26°C.
When compressor turns off half way, the accumulated time is cancelled.
When compressor turns on again, time counting starts from the beginning.
When the indoor fan speed becomes Hi or the room temperature exceeds 26°C, time counting stops temporarily.
After, when the above conditions are satisfied again, time counting restarts.
The indoor fan operates at set speed.

● Indoor fan operates at the set speed by FAN CONTROL
Followings are the fan speed in AUTO.

Room temperature minus set temperature : more than 2 ~ 4 degrees (°C)··············Hi
Room temperature minus set temperature : 1 ~ 4 degrees (°C) ·····························Me
Room temperature minus set temperature : less than 1 ~1.5 degrees (°C)·············Lo

—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 temperature and the microprocessor.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature

decrease.

The operation of the compressor and indoor fan is as follows.

1. When the room temperature is 23°C or over:

Compressor operates by temperature control and time control.

① Set temperature is controlled to fall 2°C as initial set temperature.
② 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.
Indoor fan and outdoor fan operate in the same cycle as the compressor.

1 deg.

1.5 deg.

2 deg.

4 deg.

2. When the room temperature is under 23°C.

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.

17

Operation time chart

Example

Thermostat

OFF

1st ON

ON

OFF

ON

Indoor fan

Outdoor fan
compressor

NOTE ● Coil frost prevention during DRY mode of “I FEEL CONTROL”

OFF

ON

OFF

8 min.

The operation is same as coil frost prevention during COOL mode of “I FEEL CONTROL” excepting the
indoor fan is OFF.

● Coil frost becomes the fan speed Lo during the indoor fan is OFF.
(Because the coil frost prevention is priority.)

2. COOL OPERATION

(1) Press OPERATE/STOP button.

OPERATION INDICATOR of the indoor unit

turns on with a beep tone.
(2) Select COOL mode.
(3) Set the TEMPERATURES button.

(TOO WARM or TOO COOL button)

The setting range is 16 ~ 31°C

✻ Indoor fan continues to operate regardless

of thermostat’s OFF-ON

✻ Coil frost prevention is same as COOL

mode of “I FEEL CONTROL”

3. DRY OPERATION

(1) Press OPERATE/STOP button.

OPERATION INDICATOR of the indoor unit

turns on with a beep tone.
(2) Select DRY mode.
(3) The microprocessor reads the room temper-

ature and determines the set temperature.

Set temperature is as shown in the right

chart.

Thermostat (SET TEMP.)is not work.

The other operations are same as DRY

mode of “I FEEL CONTROL”.
(4) DRY operation will not work when the room

temperature is 13°C or below.
(5) When DRY operation works, the fan speed is

lower than cool operation.

OFF

OFF

ON

ON

3 min.

OFF

OFF

4 min.

ON

ON

1 min.

18

4.FAN OPERATION

(1)Press OPERATE/STOP button.
(2)Select FAN mode.
(3)Select the desired fan speed.When AUTO,it becomes LO.(Only DRY operation)

Only indoor fan operates.Outdoor unit does not operate.

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 (Hi,Me,Lo) the
microprocessor controls IC141 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 more
smoothly than before.

(2) Fan motor lock-up protection

When the rotational frequency feedback signal is 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 flashes to
show the fan motor abnormality. (See page 25.)

6. AUTO VANE OPERATION

(1) Vane motor drive

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

(2) The auto vane angle changes as follows by pressing the VANE CONTROL button.

19

(3) Positioning

The vane is once pressed to the vane stopper below to confirm the standard position and then set to the desired angle.
The positioning is decided as follows.
(a) When the operate button is pushed. (POWER ON)
(b) When th stop button is pushed. (POWER OFF)
(c) When the vane control change AUTO to MANUAL.
(d) When the SWING is finished.
(e) When the test run starts.
(f ) When the power supply is ON.

(4) VANE AUTO mode

In VANE AUTO mode, the microprocessor automatically determines the vane angle and operation to make the optimum

room-temperature distribution.

① In COOL and DRY operation

Vane angle is fixed to Horizontal.

➁ In FAN operation

Vane angle is fixed to Downward.

(5) Dew prevention

During COOL or DRY operation with the vane angle at Downward when the compressor cumulative operation the exceeds

1 hour, the vane angle automatically changes to Horizontal for dew prevention.

(6) SWING MODE

By pressing the SWING button, vane swings vertically. The remote controller displays SWING mode is cancelled when the

SWING button is pressed again or the operation stops or changes to other mode or VANE button is pressed.

7. SLEEP MODE

• When the SLEEP button is pressed, the indoor fan speed drops and the air flow sound from the indoor unit is decrecsed.

• The indications of the remote controller are “ ” and “

• When the FAN SPEED CONTROLbutton is pressed during the SLEEP mode operation, the SLEEP made is released.

AUTO

”.

20

START STOP

START STOP

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

(3) Press ON or OFF TIMER button to select the operation.

ON-TIMER button…AUTO START operation (ON timer)
OFF-TIMER button…AUTO STOP operation (OFF timer)

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

HR. and MIN, button will work when ON or OFF TIMER button is flashing.
These marks disappear in 1minute.
When setting the ON timer, check that OPERATION INDICATOR 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.

● A power failure occurs.

● The circuit breaker functions.

2. CANCEL

Timer setting can be cancelled with the ON or OFF TIMER button.

To cancel the ON timer, press the ON-TIMER button.
To cancel the OFF timer, press the OFF-TIMER button.

Timer is cancelled and the display of set time disappears.

PROGRAM TIMER

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

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

(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.

21

9. EMERGENCY-TEST OPERATION

When the remote controller is missing, has failed or the batteries run down, press the Emergency operation switch button
on the front of the indoor unit. The unit will start and the Operation lamp will light.
The first 30 minutes of operation will be the test run operation. This operation is for servicing. The indoor fan runs at high
speed and the system is in continuous operation. The thermostat is ON and the timer is reset to normal.
After 30 minutes of test run operation the system shifts to emergency run operation with a set temperature of 24°C in
cooling.
The fan shifts to MED speed.
This operation continues until the Emergency operation switch is pressed or a button on the remote controller is pressed,
then normal operation will start.
The coil frost prevention circuit operates in this mode.
In the test run or emergency operation, auto vane operates in AUTO mode with the set temperature 24°C.

NOTE : Do not press the Emergency operation switch during normal operation.

22

9

SERVICE FUNCTIONS

9-1. 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.
3-minute time delay : 3-minute → 3-second.
AUTO START : 1 hour → 1-minute
AUTO STOP : 1 hour → 1-minute

Short the connector during the timer mode.

}

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.

(1) How to modify the remote controller P.C. board

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

NOTE : Fore remodeling, take out the batteries at first.

After finish remodeling, put back the batteries then push the RESET-button.

The P.C. board has the print “J1” and “J2”. Jumper wires are mounted to each “J1” and “J2”.Cut “J1” and “J2”
according to the number of indoor unit as shown in Table 1.
After modification, push the RESET. button near the MIN-button on the remote controller.

Table1.

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

NOTE : At power supply failure or installation, indoor unit deletes the memory about remote controller. When

the power supply is turned on and indoor unit receives the first signals from the remote controller, the
remote controller number is designated as the indoor unit number. Therefore at and after the second
time indoor unit accepts the remote controller of the initial setting number.
At setting - error, turn the power supply off to cancel the individual operation and then turn the power
supply on to restart the setting.

No modification

2 unit operation

Same as at left

Cut J1

3 unit operation

Same as at left
Same as at left

Cut J2

4 unit operation

Same as at left
Same as at left
Same as at left

Cut both J1 and J2

23

10 TROUBLESHOOTING

MS-18NN ­MS-24NN -

S1

S1

10-1 Cautions on troubleshooting

10-1-1 Before troubleshooting, check the followings:

1) Check the power supply voltage.

2) Check the indoor/outdoor connecting wire for mis-wiring.

10-1-2 Take care the followings during servicing.

1) Be sure to unplug the power cord before removing the front panel, the cabinet, the top panel, and the P.C. boards.

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

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

10-1-3 Troubleshooting procedure

1) First, check if the OPERATION INDICATION LAMP on the indoor unit is flashing to indicate an abnormality. To make
sure, check the abnormality indication for 2 or 3 times before starting service work.

2) If the P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the components for
bursting and discoloration.

3) When troubleshooting, refer to the flow chart and the check table on page 25.

10-14 How to replace batteries

Weak batteries may cause the remote controller malfunction.
In this case, the remote controller can not be repaired only by the battery replacement. To operate the remote con-

troller normally, discharge the remote controller 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.

24

10-2 Instruction of troubleshooting

Operation Indicator

Start

Indoor unit oper­ates. Outdoor unit
doesn’t operate.

Outdoor unit
operates in
only Test
Run mode.

Check room
temperature
thermistor.

Outdoor unit
doesn’t oper­ate even in
Test Run
mode.

Refer to

D

“Check of
outdoor unit”
on page 28.

Indoor unit
dosen’t receive
the signal from
remote
controller.

Refer to

B

”Check of
receiver P.C.
board” on page

27.

Indoor unit operation
monitor lamp is flashing

Indoor unit doesn’t
receive the signal from
remote controller.
Also, operation monitor
lamp doesn’t flash, when
the emergency operation

2-time flash

switch is pressed.

2.5-second OFF
3-time flash

Refer to “Check of
indoor electric control
P.C. board” on page 28.

2.5-second OFF

Cause:Indoor unit
2-time-Room temperature/Indoor coil thermistor trouble.
3-times-Indoor fan motor trouble

Check indoor coil

thermistor. Refer
to“Test point dia-

Refer to

A

“Check of indoor
fan motor” on
page 27.

Check room temperature.
Refer to“Test point dia­gram and voltage” on
page 29.

gram and voltage”
on page 29.

C

10-2-1 troubleshooting check table

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

Self check table

Abnormal

NO.

point

Indoor coil
thermistor

1

Room
tempera­ture ther­mistor

Indoor fan

2

motor

2-time flash

2.5-second OFF

3-time flash

Indication

2.5-second OFF

Symptom

Outdoor unit
does not run.

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

Detect method

Detects Indoor coil/room tem­perature thermistor short or
open circuit every 2 seconds
during operation.

When rotational frequency
feedback pulse signal is not
emit during 12-second indoor
fan operation

Repair

● Check thermistor calibration

● Reconnect connector

● Check indoor borad

● Disconnect connector CN211 and then

check connector CN121 - to make
sure rotational frequency feedback signal
of on 1.5V or over exists.

● Check indoor electronic control P.C.
board.

● Check indoor fan motor

● Reconnect conector

2

3

25

P

P

MS-18NN-

MS-24NN-

,

S1S1

10-2-2 Trouble criterion of main parts

Part name

Check method and criterion

Figure

Room
temperature
thermistor

Indoor coil
thermistor

Compressor

Indoor fan
motor

Measure the resistance with a tester.
(Part temperature 10°C ~ 30°C)

Normal

8kΩ ~ 20kΩ

Opened or short-circuited

Abnormal

Measure the resistance between the terminals with a tester.
(Coil wiring temperature-10°C ~ 40°C)

Normal

C-R
C-S

18NN

0.88~1.08Ω

1.73~2.12Ω

24NN

0.73~0.90Ω

1.61~1.97Ω

Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)

Normal

Motor part

BLK-RED

116 ~ 126
159 ~ 172Ω

ΩWHT-BLK

Measure the voltage Power ON.

Abnormal

Opened or

short-circuited

Abnormal

Opened or

short-circuited

Outdoor fan
motor

Vane motor

Normal

Sensor part

BRN-YLW
YLW-GRY

4.5 ~ 5.5V

(When fan revolved one time)

0V➔5V➔0V

(Approx.)

Remain 0V or 5V

Measure the resistance between the terminals with a tester.
(Coil wiring temperature-10°C ~ 40°C)

Normal

WHT-BLK
BLK-RED

BLK-YLW

18NN

102 ~ 126Ω

98 ~ 120Ω

-

24NN

71.5 ~ 87.5Ω

90.1 ~ 110.2Ω

80.8 ~ 99.4Ω

Measure the resistance between the terminals with a tester.
(Part temperature10°C ~ 30°C)

Normal

358 ~ 387Ω

Abnormal

Opened or short-circuited

Abnormal

18NN

Abnormal

24NN

Opened or

short-circuited

26

A

Check of indoor fan motor

Inodoor fan does not operate.

NO

Are lead wires connected?

Reconnect lead wires

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

Check of receiver P.C. board

B

Turn OFF power supply.
Check connector CN211 visually.

Yes

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

Yes ( 0 or ∞ )

Repair indoor fan motor.

Is soldered point normal?

Yes

Replace indoor electronic control

P.C. board.

No

(others)

NO

Resolder it.

Indoor unit operates by pressing the emergency ON/OFF switch, but does not operate with the remote controller.

Check the model name of remote
controller.

Is.LCD display on remote con­troller visible?

Yes

Remove batteries and then set them back.
Check if the unit operates with remote
controller.

Does the unit operate with remote
controller?

Yes

OK

No
(not clear)

No

Replace batteries.(see page 24.)

Turn a radio to AM and press switch on
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 board connector No.2
when remote controller button is pressed.

No

Yes

Replace remote controller

● Re-install the unit away from lights.

● Attach a filter on receiving part.

(+)

and No.1

Is the voltage approx. 4V DC?

No(5V or OV DC)

Replace the receiver

Yes

Replace indoor electronic control
P.C. board.

27

Check of indoor electronic control P.C. board

C

The unit doesn’t operate with
the remote controller.

Replace fuse.

Also, the operation indicator
doesn’t light up by pressing the
emergency ON/OFF switch.

Is fuse(F11)blown?

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

Yes

No

1.Pull out power supply
cord.

2.Measure resistance
between CN201

1

on electronic con­trol P.C. board and
on the terminal block
with a tester.

Trouble of indoor electronic con­trol P.C. board.

Yes

Is there resistance?
(Approx.0Ω)

N

No

Trouble of fuse(F12)

Check of outdoor unit

D

Is varistor(NR11)burnt?

Yes

Replace varistor.

No

Compressor and outdoor fan do not operate.(Only indoor fan operates.)

Yes

<MS-18NN>

Start

Press EMERGENCY ON/OFF
button. 3-minute time delay
works. Test mode operates
for 30 minutes.

Check voltage to terminal
block of outdoor unit. Is there
AC220V to terminal block

2

between - ?

N

<MS-24NN>

Start

Press EMERGENCY ON/OFF
button. 3-minute time delay
works. Test mode operates
for 30 minutes.

Check voltage to terminal
block of outdoor unit. Is there
AC220V to terminal block

2

between - ?

N

No

①
➂

CN201

Check the outdoor wiring.

L
N

Terminal
block

Check outdoor unit fan motor
and compressor.

Yes

Check continuity of indoor
and outdoor unit connection.

Check voltage to terminal
block of indoor unit. Is there
AC220V to terminal block
between - ?

Replace indoor electronic

control P.C. board.

No

2

N

No

28

Yes

Check voltage to terminal
block of outdoor unit. Is there
AC220V to terminal block

3

between - ?

Check the outdoor wiring and

N

Yes Yes

conductor relay.

Check voltage to terminal

No

block of indoor unit. Is there
AC220V to terminal block

3

between - ?

Check the indoor/outdoor
wirining.

Replace the

No

indoor

electronic

N

P.C.board

TEST POINT DIAGRAM AND VOLTAGE
MS-18NN ­MS-24NN ­Indoor electronic control P.C. board

S1

S1

Fan motor power supply

}

Fuse AC250V 3.15A

Power supply input AC220V

}

Room temperature thermistor (RT11)
Indoor coil thermistor (RT12)

+

DC5V

}

--

Indoor coil thermistor (RT12)

Room temperaure thermistor (RT11)

Time short mode point

Emergency switch

--

DC12V

}

+

29

11

DISASSEMBLY INSTRUCTIONS

NOTE:

❈ On the wiring diagram shows the terminals with a lock

mechanism, so it cannot be removed when you pull the
lead wire. Be sure to pull the wire by pushing the locking
lever (projected part) of the terminal with a finger.

11-1 MS-18NN - , MS-24NN - INDOOR UNIT

S1S1

OPERATING PROCEDURE PHOTOS

1. Removing the front panel

(1) Remove the screw caps at the bottom of the front panel.
(2) Remove the screws.
(3) Pull the bottom of the front panel to your side slightly and

unhook the catches at the top of the front panel.

(4) Remove the front panel.

2. Removing the electronic control P.C. board

(1) Remove the front panel. (Refer to 1)
(2) Remove the screw, remove the terminal cover.
(3) Remove the elect cover.
(4) Remove the screw of terminal block.
(5) Unhook the catch of the lamp holder.
(6) Remove the receiver holder.
(7) Disconnect the connector and remove the earth and the

indoor coil thermistor.

(8) Remove the electronic P.C. board.

Photo 1

Photo 2

Earth

Front panel

Screws

Indoor coil thermistor

30

Screw

Terminal
block
screw

Electrical
P.C. board

OPERATING PROCEDURE PHOTOS

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

(1) Remove the front panel.
(2) Remove the electrical box.
(3) Unhook the catch on the both sides of the nozzle assem-

bly.
(4) Remove the nozzle assembly.
(5) Remove the screws of the bearing support.
(6) Remove the screw of the heat exchanger unhook the

catch.
(7) Lifting the heat exchanger, remove the bearing support.
(8) Remove the motor support.
(9) Loose the screw fixing the line flow fan, remove the line

flow fan.
(10) Remove the screws of the side cover, remove the fan

motor.

Photo 3

Catch

Heat exchanger

screw

Bearing support
screws

Photo 4

Heat exchanger

Indoor fan motor

Line flow fan Motor band

Fan
motor
screws

31

11-2 MU-18NN - ,MU-24NN - OUTDOOR UNIT

S1S1

OPERATING PROCEDURE PHOTOS

1. Removing the cabinet

(1) Remove the screws of the cabinet.
(2) Hold the bottom of the cabinet on the both side to remove

the cabinet.

Photo 1

Photo 2

Screws

2. Removing the electrical parts

(1) Remove the cabinet.(Refer to 1)
(2) Remove the following parts.

•Compressor capacitor (C1)

•Outdoor fan capacitor (C2)

•Terminal block

•Compressor contactor(52C)(MU-24)

•Surege absorber (CR)(MU-24)

•Fan motor relay (X1)(MU-24)

•Thermal reed switch (26F1)(MU-24)

Screws

Service
panel

Photo 3

32

Compressor capacitor

OPERATING PROCEDURE

3. Removing the outdoor fan motor

(1) Remove the cabinet. (Refer to 1)
(2) Unconnect the connector remove the hooked lead wire

from the fan motor.
(3) Remove the propeller nut and remove the propeller.
(4) Remove screws fixing the fan motor.

Photo 4

PHOTOS

Hook

Connector

4. Removing the compressor

(1) Remove the cabinet. (Refer to 1)
(2) Remove the soundproof felt.
(3) Remove the terminal cover on the compressor
(4) Remove the electrical assembly.(Refer to 2)
(5) Release gas from the refrigerant circuit.
(6) Disconnect the welded part of the discharge pipe
(7) Disconnect the welded part of the suction pipe.
(8) Remove nuts fixing the compressor.
(9) Remove the compressor.

Propeller

Propeller nut

Photo 5

Glass
terminal

Suction
pipe

Discharge
pipe

Compressor

Compressor set nuts

33

PARTS LIST12

Symbol Q'ty/unit

NO. Part No. Part Name in Wiring MS-18NN- MS-24NN- Remarks

Diagram

(WH) (WH)

1

E02 138 000 FRONT PANEL

1 1

2 E02 138 010

GRILLE 1 1

3

E02 143 234

BOX 1 1

4 E02 141 100

AIR FILTER 2 2 1PC/SET

5

E02 141 970

INSTALLATION PLATE 1 1

6 E02 143 067

SCREW CAP 3 3 3PCS/SET
E02 173 007 LANP PANEL 1
E02 177 007 LANP PANEL 1

8 — AIR CLEANING FILTER — — OPTIONAL PARTS(MAC-1100FT)
9

— DEODORIZING FILTER — — OPTIONAL PARTS(MAC-1600DF)

S1

S1

7

INDOOR UNIT
STRUCTURAL PARTS
MS-18NN - (WH)
MS-24NN - (WH)

S1

S1

OPTIONAL PARTS
(See page 37)

8

9

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

34

INDOOR UNIT

Symbol Q'ty/unit

NO. Part No. Part Name in Wiring MS-18NN- MS-24NN- Remarks

Diagram (WH) (WH)
1 E02 143 235 NOZZLE 1 1
2 E02 143 040 VANE 1 1
3 E02 141 702 DRAIN HOSE 1 1
4 E02 172 300 INDOOR FAN MOTOR MF 1 1 RA4N30 -
5 E02 001 505 RUBBER MOUNT 2 2 2PCS/SET

E02 138 395 POWER SUPPLY CORD 1
E02 147 395 POWER SUPPLY CORD 1
E02 167 450 ELECTRONIC CONTROL P.C.BOARD 1

E02 176 450 ELECTRONIC CONTROL P.C.BOARD 1
8 E02 141 081 ELECTRICAL BOX 1 1
9 E02 141 302 LINE FLOW FAN 1 1

10 E02 141 303 VANE MOTOR 1 1
11 E02 138 329 DISPLAY P.C. BOARD 1 1
12 E02 141 509 BEARING MOUNT 1 1

E02 138 375 TERMINAL BLOCK TB 1

E02 209 375 TERMINAL BLOCK TB 1

14 E02 085 385 VARISTOR NR11 1 1
15 E02 139 350 INDOOR FAN CAPACITOR C11 1 1

1.8++ / 440V

16 E02 138 340 COMPRESSOR CONTACTOR 52C 1 1
17 E02 141 468 RECEIVER P.C. BOARD 1 1
18 E02 001 504 SLEEVE BEARING 1 1
19 E02 138 307 INDOOR COIL THERMISTOR RT12 1 1
20 E02 138 308 ROOM TEMPERATURE THERMISTOR RT11 1 1
21 E02 127 382 FUSE F11 1 1 3.15A

S1

S1

6713

ELECTRICAL PARTS
MS-18NN - (WH)
MS-24NN - (WH)

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

S1

S1

35

INDOOR UNIT

Symbol Q'ty/unit

NO. Part No. Part Name in Wiring Remarks

Diagram
1 E02 141 232 CABINET 1 1
2 E02 141 521 GRILLE 1 1
3 E02 141 245 SERVICE PANEL 1 1

E02 138 630 OUTDOOR HEAT EXCHANGER 1
E02 147 630 OUTDOOR HEAT EXCHANGER 1
E02 138 515 MOTOR SUPPORT 1
E02 139 515 MOTOR SUPPORT 1
E02 173 900 COMPRESSOR MC 1 NH28NCDT
E02 177 900 COMPRESSOR MC 1 NH38NBDT
E02 138 290 BASE 1
E02 176 290 BASE 1
E02 144 301 OUTDOOR FAN MOTOR MF 1 RA6V50 -
E02 147 301 OUTDOOR FAN MOTOR MF 1 RA6V60 -

9 E02 141 501 PROPELLER FAN 1 1

10 E02 082 353 COMPRESSOR CAPACITOR C1 1 1

50++ / 440V

11 E02 138 351 OUTDOOR FAN CAPACITOR C2 1 1

3.0++ / 440V

E02 141 374 TERMINAL BLOCK TB 1
E02 139 374 TERMINAL BLOCK TB 1
E02 176 936 CAPILLARY TUBE 1

[3.0 x [1.6 x350

E02 172 937 CAPILLARY TUBE 1

[3.0 x [1.4 x650

E02 147 937 CAPILLARY TUBE 1 1

[3.0 x [2.0 x700

14 E02 138 506 COMPRESSOR RUBBER SET 4 4 4 RUBBER

E02 139 662 STOP VALVE (LIQUID) 1

[6.35

E02 176 662 STOP VALVE (LIQUID) 1

[9.52

16 E02 150 661 STOP VALVE (GAS) 1 1

[15.88

17 E02 140 233 BACK PANEL 1 1
18 E02 177 342 CONTACTOR 52C 1

S1

674581215

MU-18NN-

MU-24NN-

S1

13

STRUCTURAL PARTS
MU-18NN ­MU-24NN -

S1

S1

17

11

12

10

1

4

8

2

15

16

9

5

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

36

When servicing,cut the tube to the propper length as shown in the REFRIGERANT SYSTEM DIAGRAM.See page 9.

14

6

7

3

INDOOR UNIT

Symbol

Q'ty/unit

NO. Part No. Part Name in Wiring

MS -18NN - , MS -24NN - Remarks

Diagram

(WH)

1 E02 141 426 REMOTE CONTROLLER 1
2 E02 141 083 REMOTE CONTROLLER HOLDER 1

S1

S1

Symbol Q'ty/unit

NO.

Part No. Part Name in Wiring MS-18NN- MS-24NN- Remarks

Diagram (WH) (WH)

1 E02 141 620 INDOOR HEAT EXCHANGER 1 1

E02 138 667 UNION (LIQUID) 1

[6.35

E02 176 667 UNION (LIQUID) 1

[9.52

3 E02 138 666 UNION (GAS) 1 1

[15.88

S1

S1

2

HEAT EXCHANGER PARTS
MS-18NN - (WH)
MS-24NN - (WH)

S1

S1

ACCESSORY AND REMOTE CONTROLLER PARTS
MS-18NN - (WH)
MS-24NN - (WH)

S1

S1

2

1

37

13 OPTIONAL PARTS

Pipe size O.D mm (in.)

Model Part No. Pipe length Insulation

C D
MAC-670PI 3m
MAC-671PI 5m 0

MS-18NN- MAC-672PI 7m 6.35 (1/4)

MAC-673PI

10m 45

MAC-674PI 15m 120

MAC-860PIE

3m

MAC-861PIE 5m 0

MS-24NN- MAC-862PIE 7m 9.52 (3/8)

MAC-863PIE 10m 45
MAC-864PIE 15m 120

Cross-

section

S1

Additional
refrigerant

charge
R-22(g)

A - Gas

B - Liquid

15.88 (5/8)

31

27

S1

Model Part NO.

MAC-1100FT

MS-18NN- , MS-24NN-

S1

S1

Model Part No.

MAC-1600DF

MS-18NN- , MS-24NN-

S1

S1

1. REFRIGERANT PIPES

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

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 3 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.

3. DEODORIZING FILTER

● DEODORIZING FILTER removes ammonia and hydrogen sulfide emitted from tobacco, and odors 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.

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

38

HEAD OFFICE MITSUBISHI DENKI BLDG.MARUNOUCHI TOKYO100 TELEX J24532 CABLE MELCO TOKYO

Issued in Mar. 1997. MEE No. OB188 342
Printed in Japan