Mitsubishi MCFH-24NV-EB, MUCFH-24NV-EB Service Manual

(When installed on the ceiling)

(When installed on the floor)

Note:

●Refer to OB196 REVISED EDITION-A for the details of
MCFH-24NV- and MUCFH-24NV- .

FLOOR AND CEILING TYPE AIR CONDITIONERS

SERVICE MANUAL

Wireless type
Models

EAEA

No. OB266

MCFH-24NV-

(WH)

·MUCFH-24NV-

CONTENTS

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

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

3. SPECIFICATION·················································4

4. OUTLINES AND DIMENSIONS·························5

5. WIRING DIAGRAM ············································7

6. REFRIGERANT SYSTEM DIAGRAM················8

7. PERFORMANCE CURVES································9

8. MICROPROCESSOR CONTROL ····················11

9. SERVICE FUNCTIONS ····································21

10. TROUBLESHOOTING ······································23

11. DISASSEMBLY INSTRUCTIONS·····················34

12. PARTS LIST······················································38

13. OPTIONAL PARTS ···········································42

EBEB

1

(When installed on the floor)

(When the air inlet grille is opened.)

Deodorizing filter (gray sponge type)(option)

Air filter

Remote controller

Air inlet

Operation section

Air cleaning filter (whilte bellows type)(option)

Front panel

Receiving section

Operation indicator lamp

Horizontal vane

Vertical vanes

Emergency operation switch

(When installed on the ceiling)

ACCESSORIES

Item

Installation plate
Unit fixing screw 5 o 12mm
Wireless remote controller
Remote controller mounting hardware
Fixing screw for 3.5 o 16mm (Black)
Battery (AAA) for remote controller
Drain hose
Drain pipe cover
Knockout cover
Screw for 4 o 10mm

2
2
1
1
2
2
1
1
1
2

Q'ty

TECHNICAL CHANGES

MCFH-24NV - →MCFH-24NV -

1. Only model name has changed.

MUCFH-24NV - →MUCFH-24NV -

1. Ball valve has changed to stop valve.

2. Deicer P.C. board has changed.

2

MCFH-24NV -

PART NAMES AND FUNCTIONS

EB

INDOOR UNIT

EBEA

EBEA

2

RESET

CLOCK

g

MUCFH-24NV -

OUTDOOR UNIT

Air inlet

EB

Air outlet

MCFH-24NV -

EB

3

3

Indoor model

Function

Power supply
Capacity
Air flow(High)
Dehumidification
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Fan motor current

Model
Winding

resistance(at20:)
Dimensions WOHOD

Weight
Air direction
Sound level (High)
Fan speed (High)
Fan speed regulator
Thermistor RT11(at25:)
Thermistor RT12(at25:)
Outdoor model
Air flow (High)
Compressor motor current
Fan motor current
Model
Output
Winding
resistance(at20:)
Model
Winding
resistance(at20:)
Dimensions WOHOD
Weight
Sound level(High)
Fan speed(High)
Fan speed regulator
Refrigerant filling
capacity(R22)
Refrigerating oil (Model)
Thermistor RT61(at0:)
Thermistor RT63(at0:)



kW

K /h

L/h

A
A

W

A(kW)

%

A
A




"



mm

kg

dB

rpm

k"
k"

K /h

A
A

W

"





"



mm

kg

dB

rpm

kg

cc
k"
k"



Electrical

data

Fan

motor

Special

remarks

Compressor

Electrical

data

Fan

motor

Special

remarks

Capacity

Coefficient of performance(C.O.P)

Capacity

MCFH-24NV-

EB

Cooling

6.0

3.1

12.5-11.7

2,720-2,750

-

99-98

2.21-2.18

11.56-10.76

0.58

Heating

6.2

-

11.7-11.3

2,540-2,650

-

98-98

2.44-2.34

10.76-10.36

0.58

Single phase 220 - 240 V, 50Hz

840

25

59

0.36

RB4V36-AB

WHT-BLK 82.9 BLK-YLW 65.6

YLW-BLU 36.0 BLU- BRN 27.0

BRN-RED 13.7

1,100 ✕ 650 ✕ 180

26

5

48-48

1,310-1,330

3
10
10

MUCFH-24NV-

EB

2,640-2,760

NH-47VMDT

2,200

C-R 0.96 C-S 2.07

RA6V85-AA

WHT-BLK 62.7 BLK-YLW 30.2

YLW-RED 62.9

870 ✕ 850 ✕ 295

72
53

720-750

2

2.40

1.2 (MS32N1)

33.18

33.18

SPECIFICATION

NOTE:Test conditions are based on ISO 5151

Cooling : Indoor DB27°C WB19°C Heating : Indoor DB20°C WB15°C

Outdoor DB35°C WB(24°C) Outdoor DB 7°C WB 6°C

4

4

OUTLINES AND DIMENSIONS

MCFH-24NV -

INDOOR UNIT

(When installed on the floor)

50cm or more

50cm or more

(When installed on the ceiling)

EB

100cm or more

50cm or more

50cm or more

650

80.8 906 112.8

616.5

17042.5

56

160

17.5

16

1100

Liquid line

{9.52

93

77

Gas line

{15.88

114

113

Unit: mm

143

180

5

100 10

1000For 10 units or less

200

Outdoor Unit-Necessary surrounding clearance

(Concentrated installation)

The upper side must be open.

Outdoor Unit-Necessary surrounding clearance

200

10

10

10

Note:Allow adequate

upper clearance

150

500

500

Service space

Front opening

Handle

for moving

138

95

Rear piping hole

23

33

Rear fresh

air intake

Side air intake

7 24(1)295(11-5/8)

Outlet guide

installation hole

302

Air intake

Air intake

Air outlet

870(34-1/4)

185

(7-9/32)

185

(7-9/32)

500(19-11/16)

330(13)

362(14-1/4)

1715

39.5 27.5
Terminal block for indoor and outdoor unit connection

Handle for moving

179 524

441

337

352

403

553

850(33-7/16)

40 60524

Service panel

Refrigerant-pipe flared

connection [15.88 5/8F

Refrigerant-pipe flared

connection [9.52 3/8F

Knock out hole

for front piping

(refrigerant,drainage

and wiring)

Knock out hole

for right piping

(refrigerant,drainage

and wiring)

R20

R20

60

120

4553

25 max.

Knock out holes for

power line 2-[27

Standard bolt length

65

Front right piping holes-

detail figures

80

17

42

45

12

R6

104

33

Bottom

piping hole

2-U-shaped

notched

holes

Drain hole

Drain hole

2-12o23 Oval holes

(standard bolt M10)

Handle for moving

MUCFH-24NV -

EB

Unit: mm

6

TRANSFORMER
CONTACTOR
R.V. COIL RELAY
R.V. COIL
COMPRESSOR CONTACTOR

T61
X52
X62

21S4

52

VARISTOR
DEFROST TEMPERATURE THERMISTOR
AMBIENT TEMPERATURE THERMISTOR
SOLID STATE RELAY
SOLID STATE RELAY

TERMINAL BLOCK

NR61
RT61
RT63
SR61
SR62

TB

C1
C2

DSAR

F61

MC
MF

COMPRESSOR CAPACITOR
FAN MOTOR CAPACITOR
SURGE ABSORBER
FUSE(3.15A)
COMPRESSOR (INNER PROTECTOR)
FAN MOTOR (INNER PROTECTOR)

SYMBOL SYMBOL SYMBOLNAME NAME NAME

NOTES:

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

2.Since the indoor and outdoor unit connecting wires have polarity, connect them according to the numbers (3,2,N).

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

5

SOLID STATE RELAY
TERMINAL BLOCK
CONTACTOR

SR142~SR144

TB

52C

VANE MOTOR
VARISTOR
ROOM TEMP. THERMISTOR
COIL TEMP. THERMISTOR

MV
NR11
RT11
RT12

C11
F11

HIC1

MF

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

SYMBOL SYMBOL SYMBOLNAME NAME NAME

WIRING DIAGRAM

INDOOR UNIT

POWER
SUPPLY
CORD
~/N

220-240V
50Hz

TO OUTDOOR
UNIT
CONNECTING

GRN/YLW

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

MODEL MCFH-24NV-

TB

GRN/YLW

N

BLU

L

WHT

N

BLU

2

WHT

DISP/
RECEIVER
P.C.BOARD

101CN113

5

5

3

RED

REMOTE
CONTROLLER

CN

4

SW/THERMO
P.C.BOARD

EB

HIC1

3
2
1

CN201

CN
151

4

52C

3

TRANS

BRN

ELECTRONIC CONTROL P.C BOARD

6
6

F11

MV

RT11

C11

NR11

SR144
SR143
SR142
SR141

CN
112

LDCOM

LDC11
LDC12
LDFH
LDFM
LDFL
LDFVL

22

WHT
ORN
RED
BLK
YLW
BLU
BRN

1
2
3
4
5
6
7
8

RT12

WHT
ORN
RED
BLK
YLW
BLU

BRN

GRN/YLW

MF

VG79B063H01

OUTDOOR UNIT

TO INDOOR UNIT

CONNECTING

MODEL MUCFH-24NV-

X62

X52

BLU
BLU

RT63

CN662

T61

WHT

52C

RT61

CN661

TB

3
2
N

WHT

DSAR

GRN/YLW

EB

MF

BLK

YLW

6543

YLW

BLK

SR62
SR61

DEICER PC BOARD

21

A2 A1

52C

WHT

WHT

321

CN711

NR61

ORN

RED

12

ORN

COM

RED

X62

X52

COM

F61

CN730

C1

C2

CN721

NO

TAB52

NO

WHT

RED
BLK

1
2

21S4

3

1
3
5

BLU

RED

BLU

WHT

S

C

MC

R

7

SG79J186H01

6

A: Refrigerant piping
Max.length
15m

Max. Height difference *

5m

REFRIGERANT SYSTEM DIAGRAM

MCFH-24NV-

INDOOR UNIT

Indoor
heat
exchanger

Coil temperature
thermistor
RT12

Room temperature
thermistor
RT11

Distributor

EB

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

Flared connection

Flared connection

Refrigerant pipe
(Option) [9.52
(with heat insulator)

Muffler

Stop valve
(with service port)

Accumulator

Check
valve

Strainer

Stop valve

4-way valve

Capillary tube

[3.0o[1.6o350

Capillary tube

Check
valve

Strainer

Compressor

Discharge pressure
regurator open

23.5Of/F

[3.0o[2.0o350

Capillary tube
[4.0o[2.4o200

Refrigerant flow in cooling
Refrigerant flow in heating

MUCFH-24NV-

OUTDOOR UNIT

Outdoor
heat
exchanger

EB

MAX. REFRIGERANT PIPING LENGTH & MAX. HEIGHT DIFFERENCE

Models

MCFH-24NV -

wIt does not matter which unit is higher.

EB

Refrigerant piping MAX. length : m

A

15

Piping size O.D. : mm

Gas Liquid

{15.88

{

9.52

ADDITIONAL REFRIGERANT CHARGE (R22 : g)

If pipe length exceeds 7m, additional refrigerant (R22) charge is required

Models

MCFH-24NV -

Calculation : og=65g/mo(Refrigerant piping length minus 7m)

EB

Outdoor unit:precharged

(up to 7m)

2,400 65 130 195 260 325 390 455 520

7m08m 9m 10m 11m 12m 13m 14m 15m

8

Refrigerant piping length (one way)

7

Air in

Air out

Wet-and dry-bulb
thermometers

FRONT VIEW

Wet-and dry-bulb
thermometers

BACK VIEW

PERFORMANCE CURVES

The standard data contained in these specifications apply only to the operation of the air conditioner under normal condition.
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.

(1) GUARANTEED VOLTAGE

198~264V, 50Hz

(2) AIR FLOW

Air flow should be set at MAX..

(3) MAIN READINGS

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

Indoor air wet/dry-bulb temperature difference on the left side of the chart on page 16 shows the difference between the
indoor intake air wet/dry-bulb temperature and the indoor outlet air wet/dry-bulb temperature for your reference at service.

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

How to measure the indoor air wet-bulb/dry-bulb temperature difference

1. Attach at least 2 sets of wet-and-dry-bulb thermometers to the indoor air inlet as shown in the figure, and at least 2 sets of wet­and-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 wet-and-dry-bulb thermometers to the outdoor air inlet.

Cover the thermometers to prevent direct rays of the sun.

3. Check that the air filter is cleaned.

4. Open windows and doors of the room.

5. Press the EMERGENCY OPERATION switch once(twice) to start the EMERGENCY COOL(HEAT) MODE.

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.

INDOOR UNIT

14.7

13.4

12.1

10.9

9.7

8.5

MCFH-24NV- EB

29.0

26.7

24.5

22.3

20.0

17.8

15.6

13.4

OUTDOOR UNIT

MCFH-24NV- EB

9

OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT

240V

220V

240V

220V

0.7

0.6

0.5

0.4

0.3

0.2
15 18 20 25 30 32 35(:)

50 60 70 (%)

Ambient temperature (:)

Ambient humidity (%)

Outdoor low pressure

13

12

11

10

9

8

7

15 18 20 25 30 32 35(:)

50 60 70 (%)

Ambient temperature (:)

Ambient humidity (%)

Outdoor unit current (A)

(MPa•G)

7

6

4

3

2

5

(kgf/F• G)

13

11

9

7

0 2 5 10 15 20 25(:)

Ambient temperature (:)

Outdoor unit current (A)

HEAT operation

Condition Indoor : Dry bulb temerature 20.0:

Wet bulb temerature 14.5:

Outdoor : Dry bulb temerature 7, 15, 21:

Wet bulb temerature 6, 13, 15.3:



220-240V

COOL operation

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

Dry Bulb temperature (˚C)

20
25
30

2 Air flow should be set at MAX..
3 The unit of pressure has been changed to MPa on the international system of units(SI unit system).

The converted score against the traditional unit system can be gotten according to the formula below.

1(MPa • G) =10.2(kgf/ff• G)

Relative humidity (%)

50
60
70

MUCFH-24NV-

EB

10

8

RESET

CLOCK

g

Indication

Operation state

Difference
between set
temperatuer
and room
temperature

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.

lighted
not lighted

Approx. 2 : 
or more

Approx. 2 : 
or less

Operation Indicator

OPERATION INDICATOR

lamp

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

MICROPROCESSOR CONTROL

MCFH-24NV - MUCFH-24NV -

WIRELESS REMOTE CONTROLLER

EBEB

Once the operation mode 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.

8-1. “I FEEL CONTROL”( ) OPERATION

(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.

Initial room temperature

more than 25°C

23.0°C to 25°C
less than 23°C

mode

COOL mode of

“I FEEL CONTROL”

DRY mode of

“I FEEL CONTROL”

HEAT mode of

“I FEEL CONTROL”

INDOOR UNIT DISPLAY SECTION

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

● Under the ON-TIMER( ) timer operation, 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”

Restart

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

11

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

Model

COOL mode of

“I FEEL CONTROL”

DRY mode of

“I FEEL CONTROL”

HEAT mode of

“I FEEL CONTROL”

w1 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) 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 or TOO WARM or TOO COOL buttons when you feel too warm or too cool.
Each pressing the TOO WARM or TOO COOL button ,indoor unit receives the signal a beep tone.

Initial room temperature

26°C or more

26°C or less

23°C to 25°C

23°C or less 26°C

Initial set temperature

Initial room temperature
minus 2°C

Initial room temperature
minus 2°C

24°C

w1

● 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” operation.
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)

12

— COOL mode of “I FEEL CONTROL” —

1deg.

2deg. 4deg.

1.7deg.

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

There are two types of controls in coil frost prevention as follows.

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.
During the coil frost prevention 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 is 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 Low or Med..
c. Room temperature is below 26°C.
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 26°C.
However, when two of the above conditions (b.And c.) are satisfied again time accumulation is resumed.

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

Initial temperature difference Fan speed
Room temperature minus set temperature : 2 degrees or more·········································High
Room temperature minus set temperature : 1 degree or more and less than 2 degrees···Med.
Room temperature minus set temperature : less than 1 degree·········································Low

—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 air 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 above from 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.

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.

13

Operation time chart

Example

Thermostat

OFF

1st ON

ON

OFF

Indoor fan

Outdoor fan
compressor

OFF

OFF

ON

ON

8 min.

ON

OFF

ON

OFF

3 min.

OFF

OFF

4 min.

ON

ON

1 min.

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

The operation is same as that of coil frost prevention during COOL mode of “I FEEL CONTROL”.
However the indoor fan speed becomes the set speed or Low.

— HEAT mode of “I FEEL CONTROL” —

1. Indoor fan speed control

(1) Followings are the fan speed in AUTO.

Initial temperature difference Fan speed
Room temperature minus set temperature: 2 degrees or more·········································High
Room temperature minus set temperature: 1 degree or more and less than 2 degrees···Med.
Room temperature minus set temperature: less than 1 degree·········································Low

(2) Cold air prevention control

The fan runs at set speed when the indoor coil thermistor RT12 temperature exceeds 22°C. The fan operates at Very
Low when the temperature is below 18°C. But the fan stops when the indoor fan operates at Very Low and the room
temperature is 15°C or less. Released

Cold Air Prevention

NOTE : At initial in hysteresis this control works.

18°C

22°C

(3) New warm air control.

When compressor starts in heating operation or after defrosting, the fan changes the speed with dependence on the
indoor coil thermistor RT12 temperature to blow out warm air.
After releasing of cold air prevention, when the indoor coil temperature is 37°C or above, the fan speed shifts to the set
speed, and when the fan speed is changed by the remote controller, the fan speed is the set speed.
When the indoor coil temperature is less than 37°C, the fan speed is controlled by time as below.
<Time condition> <Indoor fan speed>
less than 2 minutes························Low
2 minutes to 4 minutes···················Med.
4 minutes or more··························High
The upper limit of the fan speed is the set speed.
If the thermostat turns off, this operation changes to flow soft control.

(4) Flow soft control

After the thermostat turns off, the indoor fan operates at Very Low.
NOTE : When the thermostat turns on, the fan operates at the set speed. Due to the cold air prevention control, the fan

does not start until the indoor coil thermistor RT12 reads 22°C or more.

1 deg.

2 deg.

1.7 deg.

4 deg.

14

2. High pressure protection

During heating operation, the outdoor fan motor is controlled by the indoor coil thermistor RT12 temperature for excess rise
protection of compressor discharge pressure.
Outdoor fan OFF : OFF

Outdoor fan ON : ON

48°C

52°C

High pressure protection time chart
Indoor coil thermistor

temperature

RT12

52:

48:

Outdoor fan motor
turn OFF

Outdoor fan motor
turn ON

ON ON

Outdoor fan motor

OFF

OFF

NOTE : When the outdoor fan is OFF in heating, defrosting of outdoor heat exchanger is not detected by the defrost thermis-

tor RT61.

3. Defrosting

Defrosting of outdoor heat exchanger is controlled by deicer P.C. board, with detection by the defrost thermistor RT61.

(1) Defrost starting conditions

When all conditions of a) ~ c) are satisfied, the defrosting operation starts.

a) Under the heat operation, the compressor cumulative operation time exceeds 40 minutes without the defrosting opera-

tion working.
b) The defrost thermistor RT61 reads - 3°C or less.
c) After releasing the high pressure protection, 4 minutes and 15 seconds have elapsed.

(2) Defrost terminating conditions

When the condition d) or e) is satisfied, the defrosting operation stops.

d) The defrost thermistor RT61 reads 3.1°C or more.
e) The defrosting time exceeds 10 minutes.

15

(3) Defrosting time chart

Defrost thermistor

3.1: or more

-3: or less

Outdoor 52C relay
(Compressor)

ON

OFF

X62
(R.V.coil)

SR61
Outdoor fan

Defrost
counter

ON

OFF

ON

OFF

ON
OFF

RT61

30 sec.

15 sec.

30 sec.

5 sec.

Max. 10 min.

NOTE

ON

Indoor fan

Very Low

OFF

Position 1

Indoor vane

Set
Position

NOTE ● When the indoor coil thermistor reads above 18°C, indoor fan operates at Very Low for 30 seconds.

● When the indoor coil thermistor reads 18°C or less, the indoor fan stops.

16

4. 4-way valve control

Heating · · · · · ON
Cooling · · · · · OFF
Dry · · · · · · · · OFF

NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.

(COOL / DRY)

Compressor

4-way valve

Outdoor fan

ON

OFF
ON

OFF

ON

OFF

8-2. COOL ( )OPERATION

(1) Press OPERATE/STOP button.

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode.
(3) Set the desired temperature with the TEM-

PERATURES button.

(TOO WARM or TOO COOL button)

The setting range is 16 ~ 31°C

w Indoor fan continues to operate regardless of

thermostat’s OFF-ON

w Coil frost prevention is same as COOL mode

of “I FEEL CONTROL”

8-3. DRY ( ) OPERATION

(1) Press OPERATE/STOP button.

OPERATION INDICATOR lamp of the indoor

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

ture and determines the set temperature. Set

temperature is as shown in 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 work when the room

temperature is 13°C or below.

5 sec.

(HEAT)

5 sec.

8-4. HEAT ( ) OPERATION

(1) Press OPERATE/STOP button.

OPERATION INDICATOR lamp on the indoor unit turns on with a beep tone.
(2) Select HEAT mode.
(3) Press TEMPERATURES button (TOO WARM or TOO COOL button) to select the desired temperature.

The setting range is 16 ~ 31°C.
(4) Indoor fan speed control, high pressure protection, defrosting, 4-way valve control are same as HEAT mode of “I

FEEL CONTROL”.

17

8-5. AUTO VANE OPERATION

1

2

3

4

5

AUTO

4

1

1

2

3

4

5

(1) Vane motor drive

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

(2) Each time the VANE CONTROLbutton is pressed, angle of horizontal vane is changed in sequence, from 1,2,3,4,5 to

AUTO.

(3) Positioning

The vane is once pressed to the vane stopper to confirm the standard position and then set to the desired angle.
The positioning is decided as follows.
(a) When the OPERATE/STOP 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 vane angle and operation to make the optimum
room-temperature distribution.

1.In COOL and DRY operation

Vane angle is fixed to position 1.

2.In FAN operation

Vane angle is fixed to position 4.

(5) Dew prevention

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

(6) SWING ( )MODE

By pressing the SWING button“ ”, horizontal vane swings vertically between Position 1 and 5 in COOL and DRY opera­tion, between Position 2 and 4 in HEAT operation. The remote controller displays “ ”.If the VANE CONTROL button “ ”
or SWING button “ ” button is pressed during SWING mode or the operation stops or changes to other mode, SWING
mode is released.

(7) Cold air prevention in HEAT operation.

When any of the following conditions occurs in HEAT operation, the vane angle changes to Angle 1 automatically to pre­vent cold air blowing on users.

1 Compressor is not operating.
2 Defrosting is performed.
3 Indoor coil thermistor RT12 reads 24: or below.
4 Indoor coil thermistor RT12 temperature is raising from 24: or below, but it does not exceed 28:.

NOTE : At initial in hysteresis this control works.

Indoor coil

thermistor RT12

temperature

Position 1

24: 28:

Set position

18

8-6. TIMER OPERATION

1. How to set the timer

(1) Press OPERATE/STOP 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-TIMER, OFF-TIMER button to select the operation.

w➝| button ... AUTO START operation (ON timer)
w➝ button ... AUTO STOP operation (OFF timer)

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

HR. and MIN. button will work when w➝| or w➝ button is flashing on and off.
These marks disappear in 1 minute.
When setting the ON timer, check that POWER MONITOR lamp of the indoor unit lights.

NOTE 1 : 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 TIMER CONTROL buttons. (w➝| or w➝ )

To cancel the ON timer, press the w➝| button.
To cancel the OFF timer, press the w➝ 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 show the order of the OFF timer and ON timer operation.

(Example 1) The current timer 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.

19

8-7. EMERGENCY-TEST OPERATION

When the remote controller is missing, has failed or the batteries run down, press the EMERGENCY OPERATION
switch on the front of the indoor unit. The unit will start and the OPERATION INDICATOR 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 COOL, HEAT MODE with a set temperature of
24˚C. 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 operation,and defrosting operates too.
In the test run or emergency operation, the horizontal vane operates in AUTO mode with a set temperature of 24˚C.
Defrosting of outdoor heat exchanger works in EMERGENCY HEAT MODE.

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

EMERGENCY
OPERATION switch

OPERATION INDICATOR

Press once

<Cool>

Press again

<Heat>

Press once again

<Stop>

20

SERVICE FUNCTIONS9

MCFH-24NV -

EB

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;

“J1” and “J2” Jumper wires

NOTE : For remodelling, take out the batteries at first.

After finishing remodelling, put back the batteries then press 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, press 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

21

9-3. COMPULSORY DEFROSTING MODE FOR SERVICE

By short circuit of the connector JPG1 and R871 on the outdoor deicer P.C. board, defrosting mode can be accomplished
regardless of the defrost interval restriction. See Page 33.
Defrost thermistor RT61 must be below -3:.

9-4. DEFROST TERMINATION CHANGE

<JRF> when the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed.(See page 33.)
<JRG> when the JRG wire of the deicer P.C. board is cut, the defrost temperature will be changed.(See page 33.)

Model

MCFH-24NV -

EB

Jumper wire Change point

JRF

JRG

Defrost interval time changes from 40 minutes to 15minutes.

Defrost start temperature does not change -3:.

Defrost finish temperature changes from 3: to 15:.

22

10

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

RESET button

TROUBLESHOOTING

MCFH-24NV - MUCFH-24NV -

EB

EB

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 air inlet grille, the front panel, the cabinet, the top panel, and
the electronic control P.C. boards.

2) When removing the electronic control 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 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) 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.

3) When troubleshooting, refer to the flow chart and the check table on page 24.

10-1-4 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 con­troller 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.

1 Remove the back lid and replace batteries.

Then re-attach the back lid.

2 Press the RESET button.

23

Start

Indoor unit
operates.
Outdoor unit
doesn't
operate.

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

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

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 32
or 33.

Refer to D
"Check of
outdoor unit"
on page 28.

Refer to E
"Check of
outdoor unit"
on page 29.

Refer to B
"Check of
remote controller
and receiver
P.C. board"
on page 27.



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

• Mis-wiring

2-time flash
Cause:
Indoor unit

• Trouble of
room temp­ erature/
indoor coil
temperature
thermistor

6-time flash
Cause:
Outdoor unit

• Trouble of
thermistor
in outdoor
unit

Check room
temperature
thermistor
and indoor
coil tempera­ture thermis­tor.
Refer to
"Test point
diagram and
voltage"
on page 32
or 33.

Refer to H
"Check of
outdoor
thermistor"
on page 31.

1-time flash
Cause:
Outdoor /
Indoor unit

• Trouble of
serial signal

Refer to G
"How to
check mis­wiring and
serial signal
error (When
outdoor unit
doesn't
work)" on
page 30.
W1

Refer to G
"How to
check mis­wiring and
serial signal
error (When
outdoor unit
doesn't
work)" on
page 30.
W1

1. Check indoor /
outdoor
connecting wire.

2. Refer to C
"Check of indoor
electronic control
P.C. board"
on page 28.

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

Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.

Refer to F
"Check of
R.V. coil"
on page 29.

W1.<The case of the trouble of the serial signal>
When the power is turned off and then turned on again, the indication shows “the trouble of mis-wiring”.

7-time flash
Cause:
Outdoor unit

• Trouble of
outdoor
control
system

Refer the
deicer
P.C. board.

10-2. Instruction of troubleshooting

MCFH-24NV-

EB

24

10-2-1. Troubleshooting check table

OPERATION
INDICATOR
lamp

No.

1

2

3

SymptomOperation indicator lamp Detection method

Checkpoint

0.5-second ON

0.5-second OFF
1-time flash

2.5-second OFF

Mis-Wiring

Serial sig­nal

Outdoor
thermistor

Indoor coil
thermistor

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

When serial signal from outdoor unit stops for
4 to 5 seconds.

<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.

• Refer to H "Check of outdoor
thermistor" on page 31.

• Refer to G "How to check
mis-wiring and serial signal
error" on page 30.

• Refer to G "How to check
mis-wiring and serial signal

error" on page 29.

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 32 or 33.

Outdoor unit
does not
operate.

6-time flash

2.5-second OFF

Outdoor unit
does not
operate.

4

Outdoor
control
P.C. board

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

• Check the outdoor control
P.C. board.

7-time flash

2.5-second OFF

Outdoor unit
does not run

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.

25

10-2-2. Trouble criterion of main parts

C

S

R

BLK

RED

WHT

BLK RED ORNYLWBLU BRN

WHT

GRN

YLW

P

BRN

YLW

PNK
RED
ORN

BLU

ROTOR

BLK YLW

RED ORN

WHT

MAIN

AUX.2

AUX.1

P

MCFH-24NV -

EB

MUCFH-24NV -

EB

Part name

Room
temperature
thermistor (RT11)

Indoor coil
thermistor (RT12)

Defrost
thermistor
(RT61)

Ambient temper­ature thermistor
(RT63)

Compressor
(MC)

Check method and criterion

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

Normal

8kΩ ~ 20kΩ

Opened or short-circuited

Abnormal

Measure the resistance with a tester.
(Part temperature - 10°C ~ 40°C)

Normal

5kΩ ~ 60kΩ

Opened or short-circuited

Abnormal

Measure the resistance with a tester.
(Part temperature –10°C ~ 40°C)

Normal

5kΩ ~ 60kΩ

Abnormal

Open or short-circuit

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

Abnormal

Opened or

short-circuited

C-R
C-S

Normal

0.84~1.04Ω

1.82~2.24Ω

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

Figure

Indoor fan
motor
(MF)

Outdoor fan
motor
(MF)

Vane
motor
(MV)

Normal Abnormal

WHT-BLK

79~87Ω
BLK-YLW 63~69Ω
YLW-BLU 34~38Ω

Opened or

short-circuited

BLU-BRN 25~29Ω

BRN-RED 13~15Ω

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

Normal Abnormal

WHT-BLK

BLK-YLW

YLW-RED

55~68Ω

26~33Ω

55~68Ω

Opened or

short-circuited

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

Normal Abnormal

RED-PNK/ORN

BRN-YLW/BLU

329

~357

Ω

Opened or

short-circuited

26

p

: Inner protector

A

Check of indoor fan motor

Indoor fan does not operate.

No

Are lead wires connected?

Reconnect the lead wires.

Disconnect lead wires from connector (Fan motor).
Measure resistance between lead wires No.1 and No.4 and then No.3 and No.4 of the fan motor.

Check of remote controller and receiver P.C. board

B

Turn OFF power supply.
Check connector (Fan motor) visually.

Yes

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

Yes ( 0 or ∞ )

Replace the indoor fan motor.

Is soldered point normal?

Yes

Replace the indoor electronic control
P.C. board.

No

(others)

No

Resolder it.

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

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

Switch on the remote controller.

Is LCD display on the the remote
controller visible?

Yes

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
(not clear)

No

Replace the batteries.(Refer to page 23.)

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 (CN101) No.2(+) and No.1 when the remote con­troller button is pressed.

No

Yes

Replace the remote controller.

● Re-install the unit away from lights.

● Attach a filter on receiving part.

Is the voltage approx. 4V DC?

No(5V or 0V DC)

Replace the Disp/Receiver P.C. board.

27

Yes

Replace the indoor electronic control P.C.
board.

Check of indoor electronic control P.C. board

Yes

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

Compressor
doesn't operate.

Yes

Is there 220-240V AC
between A1-A2 on the
compressor contactor(52C)?

Operate the unit in COOL or HEAT mode by pressing the
EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.

Outdoor fan motor
doesn't operate.

No

Make the connection
of wiring correct.

Check the compressor.

Replace the compressor
contactor(52C).

Start

Yes

Is there 220-240V AC
between 2/T1 on the
compressor contactor(52C)
and N on the outdoor
terminal block?

Yes

Is there 220-240V AC
between CN730 1-3 on
the deicer P.C. board? w1

Replace the

deicer P.C. board.

Replace the

deicer P.C. board.

No

Yes

No

Is there 220-240V AC
between 1/L1 on the
compressor contactor(52C)
and N on the outdoor
terminal block?

No

No

Make the connection
of wiring correct.

Yes

Yes

Is there 220-240V AC
between CN711 1-3 or
2-3 on the deicer P.C.
board? w1

No

Make the connection
of wiring correct.

Check the outdoor fan
motor. Refer to page 25.

Yes

Is there 220-240V AC
between CN730 1-3 on
the deicer P.C. board? w1

Replace the
deicer P.C. board.

Replace the

deicer P.C. board.

No

No

+

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

+

w1 Refer to page 33.

C

The unit doesn’t operate with the

Replace the fuse.

remote controller.

Also, the OPERATION INDICATOR

lamp doesn’t light up by pressing
the EMERGENCY OPERATION

Is fuse(F11)blown?

switch.

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

D

Check of outdoor unit

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

Is varistor(NR11)burnt?

Replace the varistor.

Compressor and or outdoor fan motor doesn’t operate.

Yes

No

Trouble of the indoor electronic
control P.C. board.

No

Yes

28

Check of outdoor unit

E

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

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

After 30 seconds,
does compressor stop?

After 30 seconds, does
outdoor fan motor stop?

Check of R.V. coil

F

Ok

Ok

Yes

Yes

Is there 220-240V AC

No

between A1-A2 on the
compressor contactor?

Replace the
deicer P.C. board.

No

Replace the
deicer P.C. board.

Yes

Is there 220-240V AC
between 2/T1 on the

No

compressor contactor and N
on the outdoor terminal
block?

Replace the
compressor contactor.

Yes

Unit operates COOL mode even if it is set to HEAT mode.

w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.

Disconnect the TAB52 on the deicer P.C. board.
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.

After 3 minutes, is there
220-240V AC between CN721
1-3 on the deicer P.C. board?

Yes

Replace the R.V. coil.

No

Replace the
deicer P.C. board.

No

Make the connection
of wiring correct.

Unit operates HEAT mode even if it is set to COOL mode.

w First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.

Disconnect the TAB52 on the deicer P.C. board.
Turn ON the power supply and operate
the indoor unit in COOL mode by pressing
the EMERGENCY OPERATION switch.

After 3 minutes, is there
220-240V AC between CN721
1-3 on the deicer P.C. board?

Yes

Replace the
deicer P.C. board.

No

Replace the R.V. coil.

29

How to check mis-wiring and serial signal error (when outdoor unit doesn’t work)

G

Outdoor unit doesn’t operate.

Start

3 min. later, when Indoor 52C contactor turns ON, what self-check result
is displayed on OPERATION INDICATOR lamp on the indoor unit? ❈1

Repair wiring.

Yes

1. Turn OFF the power supply and disconnect in-out connecting wire on the indoor side.

2. Short-circuit between indoor terminal block and .

3. Turn ON the power supply and press the EMERGENCY OPERATION switch.

Is there 20V DC between both ends of R132 when
Indoor 52C contactor turns ON?
( By tester, the stylus is between 0 ~ 20V. )

Yes

1. Turn OFF the power supply.

2. Re-connect in-out connecting wire.

3. Turn ON the power supply.

1. Turn OFF the power supply.

2. Turn ON the power supply.

3. Press the

EMERGENCY OPERATION

switch.

Mis-wiring is indicated.(0.5-sec.ON, 0.5-sec.OFF)

Is there mis-wiring, poor contact, or wire disconnection?

No

3

N

No

❈1 Short circuit of JPG and JPS on the

indoor electronic control P.C. board
enables self-check to be displayed in 3
seconds.

Serial signal error is indicated.
(0.5-sec.ON, 2.5-sec.OFF)

Replace the indoor electronic control
P.C. board.

3 minutes later, when the EMERGENCY OPERATION switch is
pressed and 52C contactor turns ON, is there 220-240V AC between

N

the outdoor terminal block - ? ❈2

2

Yes

+

Is there 5V DC between J101 -J401 (MSH-

–

No

24RV) on the deicer P.C. board? Refer to page 33.
❈2

Yes

Is there 10V DC between both ends of R601 on the
deicer P.C. board? Refer to page 33. ❈2

No

(By tester, the stylus is between 5 ~10V)

Yes

Replace the deicer P.C. board.

No

Rectify in-out connecting wire.

Check and rectify the fuse and the varistor
on the outdoor deicer P.C. board.

Rectify in-out connecting wire.

❈2 While the serial signal error is indicated,

Indoor 52C contactor alternates ON for
about 10 seconds and OFF for 3 minutes.
Measure the voltage when 52C contactor
is ON.

30

Measure
resistance
between CN 661
1 and 2.

Measure
resistance
between CN 662
3 and 4.

No

Yes

Replace the
thermistor.

Reconnect CN661
and CN662.
Turn ON the power
supply and press
the EMERGENCY
OPERATION
switch.

Does the resistance
of thermistor have
the characteristics
on page 33?

No

Yes

Does the unit operate
10 minutes or more?

Replace the deicer P.C.

board.

Ok W1.

W1. It is thought defective contact of the connector.

Turn OFF the
power supply.

Ambient temperature
thermistor(RT63)

Defrost thermistor(RT61)

H

Check of outdoor thermistor

Thermistors in the outdoor unit are abnormal.

w Disconnect the connectors CN661 and/or CN662 from the deicer P.C. board.

(Check the characteristics of each thermistor.)

31

DE00R697B

To the indoor
electronic control
P.C.board CN113

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

RT11

EMERGENCY OPERATION switch

TH113

CH313

GILMS

12

0

0

10

20

30

40

10 20 30 40 50 60

Temperature ( C)

Resistance (K')

TEST POINT DIAGRAM AND VOLTAGE
MCFH-24NV -

EB

Indoor electronic control P.C. board

Fan motor power supply AC 220 - 240V

Very

Med.

Low

75643218

Low High

Fuse AC250V 3.15A

Power supply
input AC220-240V

Room temperature
thermistor(RT11)

+

DC12V

–

+

DC5V

–

CN113
Room temperature thermistor (RT11)

Time short point

Indoor coil thermistor (RT12)

32

MUCFH-24NV -



Defrost thermistor (RT61)

Ambient temperature thermistor (RT63)

-20 -10 0 10 20 30 40

0

10

20

30

40

50

60

70

80

90

100

Temperature(:)

Resistance(k")

EB

Outdoor deicer P.C. board

CN661 1-2
Defrost ther­mistor (RT61)
(Refer to
page 31.)

Defrost
interval
time short
pin(JPG1,
R871)
(Refer to
page 22.)

+

J101

(Refer to
page 28,

30.)

}

5V

DC

J401

Jumper wire for
change in defrost
setting (JRF, JRG)
(Refer to page 22.)

CN662 3-4
Ambient tempera­ture thermistor
(RT63)
(Refer to page 31.)

33

Fan motor
connector
(CN711)

Varistor
(NR62)

R.V. coil

}

(CN721)

+

12V DC

}

Fuse

3.15A / 250V

Varistor
(NR61)

CN7301-3

}

220-240V AC

(Refer to
page 28.)

R601

}

10V DC

+

(Refer to
page 30.)

DISASSEMBLY INSTRUCTIONS11

”w” 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 (project part) of the terminal with a finger.

1Slide the sleeve.
2Pull the wire while pushing the locking lever.

11-1.MCFH-24NV-

EB

INDOOR UNIT

OPERATING PROCEDURE PHOTOS

1. Removing the electronic control P. C . board.

(1) Pull out the upper part of the grill. ( photo 1 )
(2) Remove the screws of the grill.
(3) Remove screws of terminal block cover.

Remove the terminal block cover and remove the terminal

block.
(4) Remove the screws of the electronic box cover.
(5) Pull out the electronic control P. C. board.

Photo 3

Photo 1

Screws

Photo 2

2. Removing the indoor fan motor

(1) Remove the grill. ( Refer to 1(1) (2) )
(2) Remove the screws of the pipe support assembly.
(3) Remove the fan casings.(upper) .
(4) Disconnect the connector of the indoor fan motor.
(5) Disconnect the ground wire of the fan motor.
(6) Remove the screws of the motor band and remove the

catch.
(7) Take out the sirocco fan and the indoor fan motor .

34

Electronic box

Photo 4

Fan casing
(upper)

Indoor fan motor

Terminal block

Motor band

Screws

Fan
casing(upper)

OPERATING PROCEDURE PHOTOS

3. Removing the indoor heat exchanger.

(1) Remove the grill. (Refer to 1(1) (2))
(2) Remove the screws on both side and in front of the front

panel. (Photo 5)
(3) Remove the screws of the nozzle assembly. (Photo 6)
(4) Remove the electronic box . (Refer to 1)
(5) Remove the indoor fan motor . (Refer to 2)
(6) Remove the screws of the motor support .
(7) Remove the fan casing . (Iower)
(8) Remove the insullations of the drain pan and remove the

screws . (Photo 7)
(9) Remove the screws under the drain pan .(Photo 8)
(10) Remove the drain pan .
(11) Remove the indoor heat exchanger.

Photo 5

Screws

Photo 6

Screws

Photo 7

Photo 8

Insullations and screws

35

screws

11-2. MUCFH-24NV -

EB

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 1

Cabinet

Photo 2

Screws of the top panel

Top panel

Service panel

Cover panel

2. Removing the deicer 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

deicer P.C. board.

(3) Remove the deicer P.C. board.

3. Removing the propeller fan and the outdoor fan motor

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

NOTE:Loose the propeller fan in the rotating direction for

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

(3) Remove the screws and the outdoor fan motor and the

connectors.
Remove the outdoor fan motor.

Photo 3

Terminal
block

Photo 4

Propeller
fan

Propeller
fan nut

Screws of the cabinet

Deicer P.C.
board

Motor support

52C
Contactor

Separator support plate

Separator

Valve bed

36

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.
(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.

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

support.

(6) Remove the relay panel.

Disconnect the fan motor lead wires.

(7) Remove the soundproof felt.
(8) Remove the screws of the separator and the separator.
(9) Recover gas from the refrigerant circuit.
(10)

Remove the screws of the heat exchanger and the heat
exchanger.
Detach the welded part of pipe.

(11)

Remove the nuts of the compressor and the compressor.

Detach the welded part of the suction pipe and the dis­charge pipe.

NOTE

● Before using a burner, purge gas from the pipes until the
pressure gauge shows 0 MPa.

● Use the burner under the condition that gas can be released
even when the inner pressure rises by heat.

Photo 5

Screws

Rear
panel

Side
panel

Screws

Rear guard

Photo 6

Heat exchanger

Accumulator

37

Photo 7

Stop valve

Compressor

Sound
proof felt

12

No. Part No.

Part name Remark

WH

Symbol

in Wiring

Diagram

Q'ty/unit

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16

E02 227 303
E02 179 971
E02 179 100
E02 179 010
E02 179 000
E02 215 700
E02 138 666
E02 179 237
E02 179 238
E02 176 667
E02 179 972
E02 179 231
E02 227 235
E02 179 620
E02 227 040
E02 179 142

VANE MOTOR
INSTALLATION METAL (L)
AIR FILTER
GRILLE
FRONT PANEL
DRAIN PAN
UNION(GAS)
FAN CASING(UPPER)
FAN CASING(LOWER)
UNION(LIQUID)
INSTALLATION METAL (R)
BACK PANEL
NOZZLE
INDOOR HERT EXCHANGER
VANE
GRILLE CATCH

{15.88

{9.52

3PCS/SET

1
1
2
1
1
1
1
2
2
1
1
1
1
1
1
3

MV

MCFH-24NV-

EB

PARTS LIST

MCFH-24NV -

EB

12-1. INDOOR UNIT

STRUCTURAL PARTS

1

2

3

15

14

13

12

11
10

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

5

4

9

6

8

7

38

1112E02 257 426

E02 141 083

REMOTE CONTROLLER
REMOTE CONTROLLER HOLDER

1
1

MCFH-24NV

EB

-

(WH)

12-2. INDOOR UNIT

ELECTRICAL PARTS

MCFH-24NV- (WH)

EB

12-3. ACCESSORY AND

REMOTE CONTROLLER
PARTS

11

6

5

7

8

1

2

3

12-2. INDOOR UNIT ELECTRICAL PARTS

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

No. Part No.

E02 215 328

1

E02 179 505

2

E02 229 300

3

E02 179 500

4

E02 573 375

5

E02 257 375
E02 227 468

6

E02 254 307

7

E02 256 450

8

E02 127 382

9

E02 336 385

10

SWITCH BOARD
FAN MOTOR RUBBER MOUNT
INDOOR FAN MOTOR
SIROCCO FAN
TERMINAL BLOCK
TERMINAL BLOCK
RECEIVER P.C. BOARD
INDOOR COIL THERMISTOR
ELECTRONIC CONTROL P.C. BOARD
FUSE
VARISTOR

Part name Remark

Symbol

in Wiring

Diagram

MF

TB
TB

RT12

F11

NR11

12

4

Q'ty/unit

EB

24NV-

WH

1
2
1
2
1
1
1
1
1
1
1

2PCS/SET
RB4V36-

FigureA
FigureB

3.15A

MCFH-

12-3. ACCESSORY AND REMOTE CONTROLLER PARTS

39

MUCFH-24NV -

EB

12-4. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS

AND FUNCTIONAL PARTS

29

1

2

3
4

5

6

7
8

28

27

26

13

25

10

11

12

13

14

9

15 20

16 2117

18

1913

22

24

23

40

MUCFH-24NV -

EB

12-4. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS

AND FUNCTIONAL PARTS

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

Q'ty/unit

MUCFH-24NV-

1
1
1
1
1
1
1
1
1
1
1
1
3
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

NO.

E02 214 297

1

E02 540 309

2

E02 444 961

3

E02 529 490

4

E02 214 630

5

E02 214 301

6

E02 214 501

7

E07 070 508

8

E02 214 290

9

E02 527 662

10

E02 527 661

11

E02 214 232

12

E07 001 009

13

E02 527 521

14

E02 138 506

15

E02 042 900

16

E02 214 245

17

E07 001 006

18

E02 529 310

19

E02 198 374

20

E02 138 351

21

E02 128 383

22

E02 010 342

23

E02 082 353

24

E02 540 451

25

E02 214 522

26

E02 605 523

27

E02 214 249

28

E02 527 515

29

E02 262 936
E02 256 936

30

E02 176 936
E02 127 382

31

E07 336 385

32

E02 096 642

33

E02 214 642
E02 214 644

34

E02 214 384

35

Part Name

TOP PANEL
AMBIENT TEMPERATURE THERMISTOR
4-WAY VALVE
R.V. COIL
OUTDOOR HEAT EXCHANGER
OUTDOOR FAN MOTOR
PROPELLER FAN
PROPELLER FAN NUT
BASE
STOP VALVE(LIQUID)
STOP VALVE(GAS)
CABINET
HANDLE
FAN GUARD
COMPRESSOR RUBBER SET
COMPRESSOR
SERVICE PANEL
COVER PANEL
DEFROST THERMISTOR
TERMINAL BLOCK
OUTDOOR FAN CAPACITOR
SURGE ABSORBER 1
COMPRESSOR CONTACTOR
COMPRESSOR CAPACITOR
DEICER P.C. BOARD
REAR PANEL
REAR GUARD
SIDE PANEL
MOTOR SUPPORT
CAPILLARY TUBE
CAPILLARY TUBE
CAPILLARY TUBE
FUSE
VARISTOR
CHECK VALVE
CHECK VALVE
DISCHAGE PRESSUR REGULATOR
SURGE ABSORBER

Symbol

in Wiring

Diagram

RT63

21S4

MF

MC

RT61

TB
C2

DSAR

52C

C1

F61

NR61

CZ

RemarksPart No.

EB

RA6V85-



{9.52
{15.88

4RUBBERS/SET
NH-47VMDT



4P

3.0+/440VAC

S-N25 250VAC
50+/440VAC

{4.0✕{2.4✕200
{3.0✕{2.0✕350
{3.0✕{1.6✕350

3.15A

41

13

Remove the air
filter and the
deodorizing
filter together.

Separate the deodorizing
filter (gray sponge type)
from the air filter.

Remove the air
filter and the
air cleaning filter
together.

Separate the air
cleaning filter
(white bellows type)
from the air filter.

OPTIONAL PARTS

13-1. REFRIGERANT PIPES

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

Applied unit Models Pipe length

MAC-860PI
MAC-861PI

EB

MCFH-24NV -

MAC-862PI
MAC-863PI
MAC-864PI

10m
15m

3m
5m
7m

Cross-section A-Gas

{15.88

B-liquid

{9.52

Insulation

CD

{31

{27

13-2. AIR CLEANING FILTER

● If the air cleaning filter is clogged, it may lower the unit’s capacity or cause condensation at the air outlet .

● The air cleaning filter is disposable . The standard usable term is about 4 months . However , if the color of the fil-

ter turns to dark brown , replace soon .

Pipe size O.D.mm

Applied unit

Models

Additional

refrigerant

charge
R22(g)

0

195
520

MCFH-24NV-

13-3. DEODORIZING FILTER

● Clean the filter every two weeks . When it becomes too dirt , clean it more often .

● Replace the filter with a new one when its color can not be restored even after washing or when the filter becomes

dark.

● Standard interval for the filter replacement is about 1 year .

Applied unit

MCFH-24NV-

EB

EB

MAC - 1200 FT

Models

MAC - 1700 DF

42

HEAD OFFICE: MITSUBISHI DENKI BLDG.,2-2-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN

CC

Copyright 2001 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Apr. 2001. No.OB266 223
Made in Japan

New publication, effective Apr. 2001
Specifications subject to change without notice.