Mitsubishi MXZ-18TV-E1, MXZ-18TV-E2 Service Manual

SPLIT-TYPE, HEAT PUMP AIR CONDITIONER

SERVICE MANUAL

Inverter-controlled multi system
Model

Revision:

• MXZ-18TV - has been added.

• Please void OB280.

E2

No. OB280

REVISED EDITION-A

MXZ-18TV ­MXZ-18TV -

Model indication

E1

E2

CONTENTS

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

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

3. INDOOR/OUTDOOR
CORRESPONDENCE TABLE ···························3

4. INDOOR UNITS COMBINATION ·······················3

5. SPECIFICATION·················································4

6. NOISE CRITERIA CURVES······························ 5

7. OUTLINES AND DIMENSIONS························ 6

8. WIRING DIAGRAM ············································7

9. REFRIGERANT SYSTEM DIAGRAM················8

10. PERFORMANCE CURVES································9

11. MICROPROCESSOR CONTROL·····················14

12. TROUBLESHOOTING ······································19

13. DISASSEMBLY INSTRUCTIONS·····················29

14. PARTS LIST······················································32

15. OPTIONAL PARTS ···········································34

This manual describes technical data of outdoor unit.
For the indoor unit refer to the service manuals No. OB229, OB227 REVISED EDITION-B, OB252 REVISED EDI­TION-A,OC280 REVISED EDITION-A,OC281 REVISED EDITION-A and OC165 of corresponding models.

1

TECHNICAL CHANGES

MXZ-18RV - ➔ MXZ-18TV -

1. The combination pattern of indoor unit has increased.

2. Outside dimension of the outdoor unit changed.

3. Ball valve has changed to stop valve.

4. Accumulator has been removed.

5. Hight pressure switch has been removed.

6. Compressor has changed.

7. Refrigerant filling capacity has changed. (1.3kg ➝ 1.55kg)

MXZ-18TV - ➔ MXZ-18TV -

1.Combinations of the connectable indoor units have increased.

2. FUSE(F912) and Varistor(NR63) on Noise filter P.C. board has changed.

3. Accordance with the change, the board of E2 can be used for E1.

4. The board of E1 can not be used for E2.

E1E1

E2E1

2

PART NAMES AND FUNCTIONS

OUTDOOR UNIT

MXZ-18TV­MXZ-18TV-

E1
E2

Air outlet

Air inlet

(back and side)

Model indication

2

3

❈There is no combination other than this table.

MXZ-18TV-

E1

OUTDOOR UNIT

Combination of the

connectable indoor units

07+09
07+12

07+SEH-1.6

09+09
09+12

09+SEH-1.6

12+12

MXZ-18TV-

E2

07+09

07+SLH-1

07+12
07+SEH-1.6
07+SLH-1.6

09+0.9

09+SLH-1

09+12
09+SEH-1.6
09+SLH-1.6

SLH-1+SLH-1

SLH-1+12

SLH-1+SEH-1.6

SLH-1+SLH-1.6

12+12

12+SLH-1.6

SLH-1.6+SLH-1.6

07
09

12
07+09
07+12
09+09
09+12
12+12

90
90
90
90
90
90
90
90

3.88

4.17

6.22

8.79

8.85

8.88

9.00

9.07

2.3

(0.9-2.8)

2.5

(0.9-3.0)

3.4

(0.9-3.8)

4.8

(1.49-5.25)

5.0

(1.51-5.45)

5.0

(1.51-5.45)

5.2

(1.53-5.60)

5.3

(1.55-5.70)

0.850

(0.225-1.055)

0.865

(0.225-1.125)

1.29

(0.220-1.550)

1.82

(0.370-2.11)

1.835

(0.365-2.125)

1.840

(0.370-2.130)

1.865

(0.365-2.145)

1.88

(0.370-2.190)

–
–
–

2.5

2.98

2.5

3.0

2.65

2.3

2.5

3.4

2.3

2.02

2.5

2.2

2.65

Indoor units
combination

Unit A Unit B

Cooling capacity (kW)

Total

Outdoor unit

power consumption

(kW)

Current

(A)

Power

factor

(%)

230V

NOTE: Electrical data is for outdoor unit only.

MXZ-18TV -

E1 , MXZ-18TV - E2

NOTE: Electrical data is for outdoor unit only.

07
09

12
07+09
07+12
09+09
09+12
12+12

90
90
90
90
90
90
90
90

4.85

5.23

6.95

9.27

9.14

9.17

8.81

8.64

3.3

(0.9-4.0)

3.6

(0.9-4.5)

4.0

(0.9-4.7)

6.2

(1.53-6.70)

6.5

(1.55-7.00)

6.5

(1.55-7.0)

6.55

(1.56-7.1)

6.6

(1.58-7.2)

1.005

(0.225-1.115)

1.085

(0.225-1.195)

1.440

(0.220-1.490)

1.92

(0.300-2.030)

1.895

(0.295-2.005)

1.900

(0.300-2.010)

1.825

(0.295-1.925)

1.790

(0.290-1.840)

–
–
–

3.23

3.88

3.25

3.77

3.30

3.3

3.6

4.0

2.97

2.62

3.25

2.78

3.30

Indoor units
combination

Unit A Unit B

Heating capacity (kW)

Total

Outdoor unit

power consumption

(kW)

Current

(A)

Power

factor

(%)

230V

INDOOR / OUTDOOR CORRESPONDENCE TABLE

4

INDOOR UNITS COMBINATION

NOTE: SLH-1AR is equivalent to class 9 (9000BTU).

SEH-1.6AR,SLH-1.6AR is equivalent to class 12 (12000BTU).

3

5

Outdoor model

Indoor units number
Indoor units total capacity (Connectable)
indoor units total capacity (Simultaneous operation)
Piping total length
Connecting pipe length
Height difference (Indoor ~ Outdoor)
Height difference (Indoor ~ Indoor)
Function
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Crankcase heater
Power factor
Starting current
Compressor motor current
Fan motor current

Model
Output
Winding
resistance(at20:)
Model
Winding
resistance(at20:)
Dimensions WOHOD
Weight
Sound level (Hi)
Fan speed (Hi)
Fan speed regulator
Refrigerant filling
capacity(R-22)
Refrigerating oil (Model)
Thermistor RT61
Thermistor RT62
Thermistor RT63
Thermistor RT65,66
Thermistor RT67

m
m
m
m

kW

R/h

K /h

A
A

W

A(kW)

W
%

A
A
A

W

"





"



mm

kg

dB

rpm

kg

cc
k"
k"
k"
k"
k"

Compressor

Electrical

data

Fan

motor

Special

remarks

Capacity System

Coefficient of performance(C.O.P)

Outdoor unit power supply

MXZ-18TV -

E1

,

MXZ-18TV -

E2

Single phase

230V,50Hz

2
Total model name 24
Total model name 24

Max. 30 (chargeless 20)

Max. 20

10
10

1,860

20

—
—

90.0

9.08

0.38

SHV-130FEA (ROTARY)

1,400

U-V 0.45

V-W 0.45 W-U 0.45

RA6V35-AA

WHT-BLK 236.2 BLK-YLW 48.1

BLK-RED 224.1

800(+69)o600o300

46

630

2

1.55

350 (MS-56)

13.4 (at 100:)

10.0 (at 25:)

10.0 (at 25:)

10.0 (at 25:)

17.0 (at 50:)

Cooling

5.3 (1.55~5.7)
—

9.08

1,880 (370~2,190)

8.70

2.82

48

Heating

6.6 (1.58~7.2)
—

8.64

1,790 (290~1,840)

8.26

3.69

49

SPECIFICATION

NOTE: Test conditions are based on ISO 5151 (Refrigerant piping length (one way) :5m

✽1 Electrical data is for only outdoor unit.
TEST CONDITIONS COOLING INDOOR DB27.0°C WB19.0°C

HEATING INDOOR DB20.0°C

OUTDOOR DB35.0°C WB24.0°C
OUTDOOR DB 7.0°C WB 6.0°C

4

NOISE CRITERIA CURVES6

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

APPROXIMATE
TERESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, 0dB = 0.0002 MICRO BAR

BAND CENTER FREQUENCIES, Hz

Test conditions.

Cooling :DB 35: WB 24:
Heating :DB 7: WB 6:

Cooling

NOTCH

Heating

48

SPL(dB(A))

49

LINE

MXZ-18TV -

E1

MXZ-18TV -

E2

5

7

OUTLINES AND DIMENSIONS

OUTDOOR UNIT

MXZ-18TV ­MXZ-18TV -

E1
E2

Drainage hole {33

23

Bolt pitch for installation

43.6

152
Air in

45.4

16

Handle

400

347.5
Air in

Air out

113

500

800

Drainage
hole {33

155

Unit: mm

REQUIRED SPACE

Even if the right / left sides or
back side are vacant, the top
has to be at least 100mm
unobstructed.

100mm or more

34

17300

WA

200mm or more

WB

330

However, either the

left / right sides or

back side should

34

40

69

17

Handle

be unobstructed.

WA In case of poorly-ventilated place, the front

or the back has to be at least 200mm
unobstructed.

WB The wall may get dirty in case the air is

discharged toward it.

Liquid refrigerant pipe joint
Refrigerant pipe (flared) {6.35

WA

Basically

unobstructed

100mm or more

350mm or more

300

600

Service
port

165

90 65 65 65

Gas refrigerant pipe joint
Refrigerant pipe (flared) {9.52

6

8

R61

IPM

FUSE(1A)

T801

CT62

WVU

TAB61

TAB65

C65

SSR61

CN664 CN663 CN661

66

MF61

CN912CN911

21S4

CN61

R62

TAB62

V

W

U

MC

BLK

WHT

RED RED

WHT

BLK

PE

F911(1A)

BLU

ORN

YLW

TB2

BLK

BREAKER

GRN/YLW

CIRCUIT

POWER
SUPPLY
~/N
230V~
50Hz

TB1

TO INDOOR
UNIT No.B
CONNECTING
12V

TO INDOOR
UNIT No.A
CONNECTING
12V

N

L

N

3

N

3

GROUND

BLK

BLU

BLK

BLU

GRN

RED

X62

X61

X64

R64B

CT61

TAB2

TAB1

LDE

CN601CN602

CN851

TAB4

CN901

L

DS62

DS61

C61 C62

7

ORN

BLU

RED

YLW

YLW

RED

4

FUSE(20A)

ELECTRONIC CONTROL
P.C. BOARD

21 2165 4321

RT65RT66RT61RT67

LEV ALEV B

CN772 CN771

43

RT62RT63

654321 3214

123

3214567

1234567

123123

NOISE FILTER
P.C.BOARD

–

++

–

–

+

–

+

NAMESYMBOLNAMESYMBOL

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

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

3.Symbols below indicate.
:Terminal block :Connector

NAMESYMBOL

NOTES:

C61
C62

C65
CT61
CT62

DS61,DS62

FUSE
FUSE

F911

IPM

L

POWER-FACTOR CAPACITOR
SMOOTHING CAPACITOR
FAN MOTOR CAPACITOR
CURRENT TRANSFORMER
CURRENT TRANSFORMER
DIODE MODULE
FUSE(20A)
FUSE(1A)
FUSE(1A)
POWER TRANSISTOR MODULE
REACTOR

R64A,R64B

R61,R62

LEV A
LEV B

21S4

MC

MF61

RT61
RT62
RT63
RT65

RESISTOR
RESISTOR
EXPANSION VALVE A,COIL
EXPANSION VALVE B,COIL
REVERSING VALVE SOLENOID COIL
COMPRESSOR
FAN MOTOR
DISCHARGE TEMP. THERMISTOR
DEFROST TEMP. THERMISTOR
EVAPORATOR TEMP. THERMISTOR
GAS PIPE TEMP. A THERMISTOR

RT66
RT67

SSR61

T801

TB1
TB2
X61
X62

X64
CN61
F912

GAS PIPE TEMP. B THERMISTOR
FIN TEMP. THERMISTOR
SOLENOID COIL RELAY
TRANSFORMER
TERMINAL BLOCK
TERMINAL BLOCK
FAN MOTOR RELAY
FAN MOTOR RELAY
RELAY
CONNECTOR
FUSE(3.15A)

SG79J657H01

R64A

F912(3.15A)

R61

IPM

FUSE(1A)

T801

CT62

WVU

TAB61

TAB65

C65

SSR61

CN664 CN663 CN661

66

MF61

CN912CN911

21S4

CN61

R62

TAB62

V

W

U

MC

BLK

WHT

RED RED

WHT

BLK

PE

F911(1A)

BLU

ORN

YLW

TB2

BLK

BREAKER

GRN/YLW

CIRCUIT

POWER
SUPPLY
~/N
230V~
50Hz

TB1

TO INDOOR
UNIT No.B
CONNECTING
12V

TO INDOOR
UNIT No.A
CONNECTING
12V

N

L

N

3

N

3

GROUND

BLK

BLU

BLK

BLU

GRN

RED

X62

X61

X64

R64

CT61

TAB2

TAB1

LDE

CN601CN602

CN851

TAB4

CN901

L

DS62

DS61

C61 C62

7

ORN

BLU

RED

YLW

YLW

RED

4

FUSE(20A)

ELECTRONIC CONTROL
P.C. BOARD

21 2165 4321

RT65RT66RT61RT67

LEV ALEV B

CN772 CN771

43

RT62RT63

654321 3214

123

3214567

1234567

123123

NOISE FILTER
P.C.BOARD

–

++

–

–

+

–

+

NAMESYMBOLNAMESYMBOL

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

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

3.Symbols below indicate.
:Terminal block :Connector

NAMESYMBOL

NOTES:

C61
C62

C65
CT61
CT62

DS61,DS62

FUSE
FUSE

F911

IPM

L

POWER-FACTOR CAPACITOR
SMOOTHING CAPACITOR
FAN MOTOR CAPACITOR
CURRENT TRANSFORMER
CURRENT TRANSFORMER
DIODE MODULE
FUSE(20A)
FUSE(1A)
FUSE(1A)
POWER TRANSISTOR MODULE
REACTOR

R64

R61,R62

LEV A
LEV B
21S4

MC
MF61
RT61
RT62
RT63
RT65

RESISTOR
RESISTOR
EXPANSION VALVE A,COIL
EXPANSION VALVE B,COIL
REVERSING VALVE SOLENOID COIL
COMPRESSOR
FAN MOTOR
DISCHARGE TEMP. THERMISTOR
DEFROST TEMP. THERMISTOR
EVAPORATOR TEMP. THERMISTOR
GAS PIPE TEMP. A THERMISTOR

RT66
RT67

SSR61

T801

TB1
TB2
X61
X62
X64

CN61

GAS PIPE TEMP. B THERMISTOR
FIN TEMP. THERMISTOR
SOLENOID COIL RELAY
TRANSFORMER
TERMINAL BLOCK
TERMINAL BLOCK
FAN MOTOR RELAY
FAN MOTOR RELAY
RELAY
CONNECTOR

SG79J191H01

WIRING DIAGRAM

OUTDOOR UNIT

OUTDOOR UNIT

MODELS MXZ-18TV-

MODELS MXZ-18TV-

E1

E2

7

9

a

Outdoor
unit

b

H

H

H

REFRIGERANT SYSTEM DIAGRAM

MXZ-18TV ­MXZ-18TV -

Stop valve
(with service port)

Indoor
Unit B

Indoor
Unit A

Stop valve
(with service port)

Indoor
Unit A

Indoor
Unit B

E1
E2

Stop valve

Stop valve

Discharge
temperature
thermistor

Gas pipe temperature
B thermistor

Muffler

Gas pipe temperature
A thermistor

Capillary tube

{3.0✕{2.0✕400

{6

Strainer

{6

Strainer

Capillary tube
{3.0✕{2.0✕400

Compressor

Muffler

4-way valve

LEV (A)

LEV (B)

{8

Capillary tube

{2.4✕{0.6✕750

{16

Evaporation
temperatuer
thermistor

R.V. coil
heating ON
cooling OFF

{12

Unit:mm

Refrigerant flow in cooling
Refrigerant flow in heating

Outdoor

heat

exchanger

Defrost
thermistor

Capillary tube
{4.0✕{2.4✕300

MAX REFRIGERANT PIPING LENGTH

-

MXY-18TV
MXY-18TV

Piping length each indoor unit (a, b) 20m
Total piping length (a+b) 30m
Height difference between units (H) 10m
Bending point for each unit 15
Total bending point 30

❋It does not matter which unit is higher.

● Refrigerant pipe diameter is different according to indoor unit to be connected. When using extension pipes,refer to the

tables below.

● When diameter of refrigerant pipe is different from that of outdoor unit union, use optional Different-diameter pipe.
For further information on Different-diameter pipe, see page BACK COVER.

class Pipe diameter

07/09

12

NOTE: SEH-1.6AR is equivalent to class 12.

E1

-

E2

Indoor unit

Extension pipe diameter

Liquid 6.35(1/4) Liquid 6.35(1/4)

Gas 9.52(3/8) Gas 9.52(3/8)

Liquid 6.35(1/4) Liquid 6.35(1/4)

Gas 12.7(1/2) Gas 12.7(1/2)

Outdoor unit union diameter

For

Indoor unit A

Indoor unit B

Unit : mm (inch)

Liquid 6.35(1/4)

Gas 9.52(3/8)

Liquid 6.35(1/4)

Gas 9.52(3/8)

8

10

Wet-and dry-bulb
thermometers

Wet-and dry-bulb
thermometers

07 class

7.7

7.2

6.6

6.1

5.5

5.0

9.3

8.6

7.9

7.3

6.6

6.0

8.4

7.8

7.2

6.6

6.0

5.4

12 class

09 class

25.9

23.9

21.9

19.9

17.9

15.9

13.9

11.9

23.6

21.8

19.9

18.1

16.3

14.5

12.7

10.9

25.7

23.7

21.8

19.8

17.8

15.8

13.8

11.9

07 class

09 class

12 class

PERFORMANCE CURVES

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.

(1) GUARANTEED VOLTAGE

198 ~ 264V

, 50Hz

(2) AIR FLOW

Air flow should be set at MAX.

(3) MAIN READINGS

(1) Indoor intake air wet-bulb temperature : °CWB
(2) Indoor outlet air wet-bulb temperature : °CWB
(3) Outdoor intake air dry-bulb temperature : °CDB

}

Cooling

(4) Total input: W
(5) Indoor intake air dry-bulb temperature : °CDB
(6) Outdoor intake air wet-bulb temperature : °CWB
(7) Total input : W

Heating

}

Indoor air wet/dry-bulb temperature difference on the left side of the chart on page 10 and 11 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.

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 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 wet-and 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 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 OUTDOOR UNIT

10-1. CAPACITY AND THE INPUT CURVES

9

10-2. Capacity and input correction by inverter output frequency

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

0 50 100 150

0.5

1.0

1.5

<COOL>Capacity

Frequency

Hz

Frequency

<COOL>Total input

Hz Hz

<HEAT>Capacity

Frequency

Frequency

<HEAT>Total input

Hz

<COOL>Capacity

Frequency

Hz

Frequency

<COOL>Total input

Hz

<HEAT>Capacity

Frequency

0 50 100 150

0.5

1.0

1.5

Frequency

<HEAT>Total input

Hz

<COOL>Capacity

Frequency

Hz

Frequency

<COOL>Total input

Hz

<HEAT>Capacity

Frequency

Hz

Hz

Frequency

<HEAT>Total input

Hz

1. 07-class unit in single operation

2. 09-class unit in single operation

3. 12-class unit in single operation

NOTE 1 : Inverter output frequency : COOL 55Hz,HEAT 80Hz

(OUTDOOR UNIT:MXZ-18TV)

NOTE 2 : The dotted line on graphs connects the frequency range in normal operation shown by the full line and the frequency

in test run shown by the point.

10

10-3. Outdoor low pressure and outdoor unit current

1. 07-class unit in single operation (OUTDOOR UNIT : MXZ-18TV)

NOTE: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)

(1) COOL operation

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

Dry-bulb temperature(°C) Relative humidity(%)

20 50
25 60
30 70

2Air flow speed : HI
3Inverter output frequency : 55Hz

(kgf/F• Gauge)

Outdoor low pressure

(MPa•Gauge)

8

7

6

5

4

3

2

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Ambient temperature(:)/ Ambient humidity(%)

20 25

18

50 60

30
70

55Hz

32

<How to work fixed-frequency operation>

1.Set emergency switch to COOL or HEAT.The switch is locat­ed on indoor unit.

2.Press emergency run ON/OFF button.

3.Compressor starts running at 55Hz (COOL) or 80Hz (HEAT).

4.Indoor fan runs at HI speed and continues for 30 minutes.

5.To cancel this operation,press emergency run ON/OFF button
or any button on remote controller.

4

55Hz

3.5

3

2.5

2

Outdoor unit current (A)

1.5

(%)

(:)

0.5

Ambient temperature(:)/ Ambient humidity(%)

20 25

18

50 60

30
70

32

(:)

(%)

(2) HEAT operation

①

Indoor Outdoor

➁

Set air flow to Hi speed.

➂

Inverter output frequency is 80Hz.

DB(°C) 20.0

WB(°C) 14.5

DB(°C) 2 7 15 20.0

WB(°C) 1 6 12 14.5

8

7

6

5

4

Outdoor unit current (A)

3

2

2 5 10 15 20 25

80Hz

Ambient temperature(:)

11

2. 09-class unit in single operation (OUTDOOR UNIT : MXZ-18TV)

NOTE: 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)

(1) COOL operation

1Both indoor and outdoor units are under the same

temperature/humidity condition.

Dry-bulb temperature(°C) Relative humidity(%)

20 50
25 60
30 70

2Air flow speed : HI
3Inverter output frequency : 55Hz

<How to work fixed-frequency operation>

1.Set emergency switch to COOL or HEAT.The switch is locat­ed on indoor unit.

2.Press emergency run ON/OFF button.

3.Compressor starts running at 55Hz (COOL) or 80Hz (HEAT).

4.Indoor fan runs at HI speed and continues for 30 minutes.

5.To cancel this operation,press emergency run ON/OFF button
or any button on remote controller.

(kgf/F• Gauge)

Outdoor low pressure

(2) HEAT operation

①

Indoor Outdoor

➁

Set air flow to Hi speed.

➂

Inverter output frequency is 80Hz.

(MPa•Gauge)

0.8

8

0.7

7

0.6

6

0.5

5

0.4

4

0.3

3

2

0.2

Ambient temperature(:)/ Ambient humidity(%)

DB(°C) 20.0

WB(°C) 14.5

18

20 25
50 60

4

55Hz

30

32

(:)

70

DB(°C) 2 7 15 20.0

WB(°C) 1 6 12 14.5

(%)

3.5

3

2.5

Outdoor unit current (A)

2

1.5

Ambient temperature(:)/ Ambient humidity(%)

18 20 25 30

50 60 70

55Hz

32

(:)

(%)

12

8

7

6

5

4

Outdoor unit current (A)

3

2

2 5 10 15 20 25

Ambient temperature(:)

80Hz

3. 12-class unit in single operation (OUTDOOR UNIT : MXZ-18TV)

NOTE: 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)

(1) COOL operation

1Both indoor and outdoor units are under the same

temperature/humidity condition.

Dry-bulb temperature(°C) Relative humidity(%)

20 50
25 60
30 70

2Air flow speed : HI
3Inverter output frequency : 55Hz

<How to work fixed-frequency operation>

1.Set emergency switch to COOL or HEAT.The switch is locat­ed on indoor unit.

2.Press emergency run ON/OFF button.

3.Compressor starts running at 55Hz (COOL) or 80Hz (HEAT).

4.Indoor fan runs at HI speed and continues for 30 minutes.

5.To cancel this operation,press emergency run ON/OFF button
or any button on remote controller.

(kgf/F• Gauge)

Outdoor low pressure

(2) HEAT operation

①

Indoor Outdoor

➁

Set air flow to Hi speed.

➂

Inverter output frequency is 80Hz.

(MPa•Gauge)

8

7

6

5

4

3

2

0.8

0.7

0.6

0.5

0.4

0.3

0.2

DB(°C) 20.0

WB(°C) 14.5

18

Ambient temperature(:)/ Ambient humidity(%)

20 25
50 60

4

3.5

55Hz

3

2.5

2

Outdoor unit current (A)

1.5

32

30
70

DB(°C) 2 7 15 20.0

WB(°C) 1 6 12 14.5

(:)

(%)

1

Ambient temperature(:)/ Ambient humidity(%)

18 20 25 30

50 60 70

55Hz

32

(:)

(%)

13

8

7

6

5

4

Outdoor unit current (A)

3

2

2 5 10 15 20 25

Ambient temperature(:)

80Hz

11

Compressor
power
factor

Indoor unit
microprocessor

SSR61

Drive

circuit

Transistor

module

Indoor Unit

B

Indoor Unit

B

Comp.

Discharge
temperature
thermistor
RT61

Evaporation
temperature
thermistor
RT63

Gas pipe
temperature
thermistor RT66

Gas pipe
temperature
thermistor RT65

Indoor Unit

A

Indoor Unit

A

Outdoor
fan motor
MF61

x 61
x 62

Defrost
thermistor
RT62

LEV (A)

LEV (B)

Outdoor unit control microprocessor

Compressor
primary
current

Compressor
secondary
current

Fin temperature
thermistor RT67

R. V. coil
21S4

Input signal

Output signal

MICROPROCESSOR CONTROL

INVERTER MULTI SYSTEM CONTROL
MXZ-18TV -

MXZ-18TV -

E1
E2

14

11-1.LEV control

Linear expansion valve (LEV) is controlled by "Thermostat ON" commands given from each unit.

Indoor unit status
Stop of all indoor unit

Opening before stop ➝ 500 pulse in 15 minutes

When outdoor unit is operating,
some indoor unit stops and
some operates.

Thermostat OFF in

COOL or DRY mode

When the outdoor unit operation (When the other indoor unit operate): 5 pulse.
When outdoor unit stops. (When the other indoor unit stops or thermo off):
Maintain LEV opening before stop ➝ 500 pulse in 15 minutes

• LEV opening for each indoor unit is determined by adding adjustment in accordance
with the number of operating unit and the capacity class to standard opening, based
on the operation frequency:
Ex.) Opening 130 pulse in standard opening 1 ➝ Minimum 80 pulse, Maximum 205

Thermostat ON in

COOL or DRY mode

pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 unit operation)

• After starting operation, adjustment in accordance with intake super heat, discharge
temperature is included in standard opening. w1

Note: LEV opening in each frequency at DRY operation and COOL operation is the

same. However, velocity and compressor operation frequency controls are
different. See 11-2 Operational frequency range
(As far as the indoor unit velocity control goes, refer to DRY operation in
MICROPROCESSOR CONTROL in the indoor unit service manual.)

• When the outdoor unit operates. (When the other indoor unit operates): 59 pulse

Thermostat OFF in HEAT mode

• When the outdoor unit stops. (When the other indoor unit stops or thermo off):
Maintain LEV opening before stop ➝ 500 pulse in 15 minutes.

• LEV opening for each indoor unit is determined by adding adjustment in accordance
with the number of operating unit and the capacity class to standard opening, based

Thermostat ON in HEAT mode

on the operation frequency:
Ex.) Opening 120 pulse in standard opening 1 ➝ Minimum 70 pulse, Maximum 165
pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 unit operation)

• After starting operation, opening becomes the one that adjustment in accordance
with discharge temperature was added to basic opening. w1

w1 LEV opening when the outdoor unit operating: Upper limit 500 pulse, Lower limit 59 pulse.

LEV opening

COOL : 5 pulse (full closed)
HEAT : 59 pulse (slightly opened)

Determination of LEV standard opening in each indoor unit

• The standard opening is on the straight line, which connects an each standard point in the section where divided
into seven according to the operation frequency of compressor as shown in the figure below.
(LEV opening is controlled in proportion to the operation frequency.)

Note: Opening is adjusted at the standard opening according to the indoor unit conditions.

However, inclination of standard opening in each point of opening does not change with the original curve.

• Add opening provided in Difference in Capacity in the table below to the standard opening from 1 to 8,
when capacity of the indoor unit is excluding code 1.

• Add opening provided in Difference in Operation number in the table below to determined LEV opening for
each indoor unit, when 2, 3 or 4 indoor units are operated at the same time.

Note: Even when the adjusted standard opening exceeds the driving range from 59 to 500 pulse, actual

driving output opening is in a range from 59 to 500 pulse.
< Calculation example of LEV opening >
Cool operation: Compressor frequency 70Hz: 2 unit ON: 18class
(170-150)p(80-60)o(70-60)+150+75-30=205 pulse

Standard opening

12345678

220
210
200
190
180
170
160
150
140

LEV opening (Pulse)

130
120

7 20 40 60 80 100 120 140

COOL

HEAT

Operation frequency of compressor (Hz) : F

15

(1) LEV opening correction by suction super heat (COOL, DRY)

Suction superheat (S.H.)

LEV opening
correction (pulse)

more than 12

10 to12

8 to 10

6 to 8

6 or less

6
4
3
2
0

Difference of
superheat

LEV opening
correction (pulse)

more than 9

6 to9
3to 6

6 or less

8
6
2
0

1 Suction super heat

(MIN gas pipe temperature thermistor - Evaporation temperature thermistor)

2 Each correction w 1

• (Each gas pipe temperature thermistor - Evaporation temperature thermistor)

• (Main pipe temperature thermistor - sub pipe temperature thermistor)

w 1 Perform this, when number of operation units is 2units or more
w 2 When the correction opening of suction super heat is 0, correct the LEV opening by dischaege temperature.

3 Discharge temperature

COOL DRY HEAT

••

-

•

w 2

•

w 2

•

<Correction>

2

Code3Code2

Standard opening

Difference in
capacity

Difference in
operation number

12345678

COOL

HEAT

150
120

160
130

170
140

180
150

Capacity code

Indoor unit

1

07209312418

190
160

190
170

200
180

200
180

25
20

50
40

-60

-60

(Suction super heat) = (Minimum gas pipe temperature) - (Evaporation temperature)

When COOL and DRY , correct the LEV openings corrected from the table below

(2) Separate correction (COOL,DRY)

(When number of operation unit is 2 units)
(a) Correction by the separate super heat

Correct the LEV separately by temperature difference between each gas pipe temperature thermistor and evaporator
temperature thermistor.
1 Calculate each super heat of the unit from the expression below;

(Super heat) = (Gas pipe temperature thermistor) - (Evaporation temperature thermistor)

2 Select a minimum super heat from among them.
3 Correct an each LEV is corrected opening is corrected by difference between each super heat and minimum super

heat.

16

(3) LEV opening correction by discharge temperature

Operation frequency
of compressor

Minimum ~ 20

21 ~ 33
34 ~ 46
47 ~ 59
60 ~ 72
73 ~ 85
86 ~ 98

97 ~ 111

111 ~ Maximum

Single

40
40
45
45
50
55
65
70
75

Double

40
40
45
45
50
55
65
70
75

Single

40
45
50
55
60
65
70
75
75

Double

40
45
50
55
60
65
70
73
73

Number of operating unit. Number of operating unit.

COOL, DRY HEAT

Discharge temperature (;)

LEV opening
correction (pulse)

more than Target discharge temperature+11
Target discharge temperature+11 to Target discharge temperature+8
Target discharge temperature+8 to Target discharge temperature+5
Target discharge temperature+5 to Target discharge temperature+2
Target discharge temperature+2 to Target discharge temperature-2
Target discharge temperature-2 to Target discharge temperature-5
Target discharge temperature-5 to Target discharge temperature-8
Target discharge temperature-8 to Target discharge temperature-11
Target discharge temperature-11 or less

COOL

10

4
2
1
0

-1

-2

-5

-8

HEAT

8
2
1
1
0

-1

-1

-2

-6

DRY

Min. Max. Rated Min. Max.

Defrost

Rated

Note: When the fan speed of indoor unit is total
Lo notch, the maximum frequency is
rated frequency.

COOL

HEAT

Number of

operating

unit

1
2
3
2
3
4
5
6
7

30

30

70
80

100

120

55
61
85

108

30
41
53

723030

100
100
120

120

100
100
100

100

80
85
94

120

1

2

capacity

cord

When LEV correction output is 0 pulse by the suction super heat at cool or dry operation, or dry operating, correct LEV is cor­rected according to the following table.

The target discharge temperature is determined according to frequency zone and number of operation unit of the
compressor.

Correct the LEV opening according to difference between the target discharge temperature and discharge temperature.

11-2.Operational frequency range

11-3.Heat defrosting control

(1) Conditions to enter defrosting mode

1. When temperature of defrosting thermistor is -3; or less.

2.When specified non-defrosting time, is counted in the control p.c.board is satisfied.

(Total time of compressor operating)
Going to defrosting mode at both condition of 1 and 2.

(2) Defrosting operation

1. Compressor stops for 50 seconds, Indoor fan is off, Defrosting lamp lights

2.4-way valve reverses flow, Compressor operates by the frequency in heat defrosting control.

3. After compressor stops for 35 seconds, 4-way valve reverses flow, then defrosting finishes.

(3) Conditions to finish defrosting mode

1. When the defrosting thermistor temperature is 8; or more.

2. When it has spent 10 minutes for defrosting.

Defrosting finishes at condition of 1 or 2.

17

11-5.Discharge temperature protection control

COOL

Fan speed

Up

Down

Up

Down

Single Double

Mode

HEAT

Indoor unit operation

<Relation between compressor frequency and fan speed.>

60Hz
50Hz
60Hz
50Hz

60Hz
50Hz
60Hz
50Hz

Up

Down

Fan speed

Hi

Low

Compressor frequencyMin. Max.

Discharge temperature thermistor
Indoor pipe temperature thermistor
Defrost thermistor
Evaporation temperature thermistor
Gas pipe temperature thermistor
Fin temperature thermistor
Capacity code

Purpose

Protection

Defrosting Protection

Defrosting

Control
Control

Protection

Control

Compressor LEV

Outdoor
fan motor

Reversing

valve

Sensor

Actuator

This protection controls the compressor ON/OFF and operation frequency according to temperature of the discharge temp.
thermistor.

(1) Compressor ON/OFF
When temperature of the discharge temp. thermistor exceeds 116;, the control stops the compressor.
When temperature of the discharge temp. thermistor is 80; or less, the controls starts the compressor.

(2) Compressor operation frequency
When temperature of the discharge temp. thermistor is expected to be higher than 116;, the control decreases 12Hz from the

current frequency.

When temperature of the discharge temp. thermistor is expected to be higher than 111; and less than 116;, the control

decreases 6Hz from the current frequency.

When temperature of the discharge temp. thermistor is expected to be higher than 104; and less than 111;, the control is set

at the current frequency.

11-6.Refrigerant recovery control on heating

<Control status>

The control performs when the following status are satisfied everything;

• When there is 1 unit or more not operating indoor unit on heat operation. (Excluding thermo OFF)

• When discharge temperature becomes 107; or more.

• When it passed 60 minutes or more since the operation has started or the last refrigerant recovery has controlled.

<Control details>

LEV opening, which adjusts to not operating indoor unit, is considered to be 80 pulse.

<Control finish status>

The control finishes either as follows. However, the LEV opening is considered to be 59 pulse.

• When it passed 60 seconds since the control has started.

• When the discharge temperature is 90; or less.

11-7.Outdoor fan control

Fan speed is switched according to a number of operating indoor unit and the compressor frequency.

Note

•When operation, fan speed of Hi/ Low mode changes to VHi/ Hi mode by promoting those fan speeds respectively by
1 step after defrosting is operated. This control is cleared, when the compressor off.

•When overheat protection of P.C. board temperature or fin temperature operates, the outdoor fan speed is fixed to VHi
mode regardless of compressor frequency. Also, when the overheat protection is cleared, the fan speed is
back to normal

•When the indoor coil thermistor is 57; or more on HEAT operation, fan speed is fixed to Low notch .
Or, the indoor coil thermistor is 45; or less on HEAT operation, fan speed is back to normal.

11-8.Relation between main sensor and actuator

Relation between main sensor and actuator.

18

12 TROUBLESHOOTING

Lead wiring

Housing point

Operation start

Check the outdoor unit
LED indicator

A Check of power supply
See page 22.

• Indoor unit
serial signal
error
B Check of
serial signa
See page 22.

• Cool or HEAT
opereation only
C Check of
R.V.coil
See page 23.

• When cooling,
room does not
cool.
E Check of
inverter,
compressor
See page 24.

• When cooling, heat
exchanger of
non-operating indoor
unit frosts.

•When heating, non
operating indoor unit
gets warm.
D Check of LEV
See page 24.

• When cooling,
dew drops in the
non-operating
indoor unit
Check of mis­piping.

• When heating,
room doed not get
warm.
E Check of
inverter,compressor
See page 24.
Check mis-piping
Shortage of capacity

Refer to indicator list
See page 20, 21.

OFF

Both LED 1 and
LED 2 lighting

• Check the indoor unit with referring to the indoor unit service manual, and confirm that there is any problem in the indoor unit.
Then, check the outdoor unit with referring to this page.

LED 1 or LED 2
has blinked.

12-1. Cautions on troubleshooting

1. Before troubleshooting, check the following:

1) Check the power supply voltage.

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

2. Take care the following during servicing.

1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the unit, and then after con­firming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.

2) Be sure to unplug the power cord before removing the front panel, the cabinet, the top panel, and the electronic con­trol P.C. board.

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

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

3. Troubleshooting procedure

1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.

To make sure, check how many times the abnormality indication is flashing on and off before starting service work.

2) 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 on page 19 and the check table on page 20, 21.

12-2. Instruction of troubleshooting

19

Troubleshooting check table <OUTDOOR UNIT>

LED 1 (red)

Lighting

Indication

LED 1

Lighting

Lighting

6 times Goes out

Lighting

LED 1

Lighting

Lighting

(red)

Indication

(red)

LED 2

(Yellow)

Twice

7 times

9 times

LED 2

(Yellow)

3 times

4 times

LED 2 (yellow)

Lighting

Symptom: Outdoor unit does not operate.

Abnormal point Detecting method Check points

Outdoor power system

Outdoor control system

Indoor unit and LEV

DC voltage sensing cir­cuit

Abnormal point Detecting method Check points

Discharge temperature
thermistor

Fin temperature ther­mistor

When the compressor operation has been interrupted by overcurrent
protection continuously three times within 1 minute after start-up.

When the nonvolatile memory data cannot be read properly on the out­door electronic control P.C. board.

When the drain abnormality is detected in the indoor unit and the indoor
unit coil temperature is too low, or when any abnormality is detected in
the components of indoor unit.

When DC voltage sensing circuit detects 57V or below or 395V or above

Symptom: Outdoor unit repeats to stop and restart in 3 minutes

When a short or open circuit occurs in the discharge temperature ther­mistor during compressor running.

When a short or opern circuit occurs in the fin temperature thermistor
during compressor running.

Error mode

Normal

• Check the inverter / compressor.
Refer to “E” on page 24.

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

• Check the abnormality indication on the
indoor unit.

• Check the LEV.

Refer to “D” on page 24.

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

• Check the characteristic of the discharge
temperature thermistor.

Refer to “F” on page 25.

• Check the connector. (CN663)

• Check the characteristic of the fin temper­ature thermistor.

Refer to “F” on page 25.

• Check the connector. (CN664)

Lighting

Lighting

Lighting

Lighting

3 times Goes out

4 times Goes out

4 times Goes out

5 times

10 times

11 times

12 times

Twice Goes out

P.C. board temperature
thermistor

Evaporation tempera­ture thermistor

Gas pipe temperature A
thermistor

Gas pipe temperature B
thermistor

Over current protection When over current is applied to the power module.

Discharge temperature
overheat protection

Fin temperature over­heat protection

P.C. board temperature
overheat protection

When a short or open circuit occurs in the P.C. board temperature ther­mistor during compressor running.

When a short or open circuit occurs in the evaporation temperature ther­mistor during compressor running.

When a short or open circuit occurs in the gas pipe temperature Ather­mistor during compressor running.

When a short or open circuit occurs in the gas pipe temperature B ther­mistor during compressor running.

When the discharge temperature thermistor detects 116: or above.
(Protection will be released at 100: or below.)

When the fin temperature thermistor detects 91: or above.

When the P.C. board temperature thermistor detects 79: or above.

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

• Check the characteristic of the evaopra­tion temperature thermistor.

Refer to “F” on page 25.

• Check the connector. (CN663)

• Check the characteristic of the gas pipe
temperature A thermistor.

Refer to “F” on page 25.

• Check the connector. (CN661)

• Check the characteristic of the gas pipe
temperature B thermistor.

Refer to “F” on page 25.

• Check the connector. (CN661)

• Check the inverter / compressor.

Refer to “E” on page 24.

• Check the amount of gas.

• Check the indoor / outdoor air flow for
short cycle.

• Check the indoor unit air filter for clogging.

• Check the amount of gas and the refriger­ant cycle.

• Check the outdoor unit air passage.

• Check the outdoor unit air passage.

• Check the outdoor fan motor.

Refer to “G” on page 25.

• Check the power module.

• Check the outdoor unit air passage.

• Check the outdoor fan motor.

Refer to “G” on page 25.

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

20

Indication

W

U

V

WHT

RED

BLK

WHT

Protector specification

Short
Open

87I15:
135I5:

YLW

P

ORN
RED

BLK

LEV

WHT

RED

YLW

BRN

ORN

BLU

LED 1

LED 2

(red)

(Yellow)

Once Lighting

Symptom: Oudtoor unit operates (The compressor operates at reduced frequency)

Abnormal point Detecting method Check points

Current protection When the outdoor unit input current exceeds 15.5A.

Overload protection When the compressor load exceed the specified value.Twice
High pressure protec-

tion
Defrosting in cooling
Discharge temperature

protection
Low discharge tempera-

ture protection

LED 2

Defrost thermistor

Power factor detection When the compressor power factor cannot be detected. • Check the compressor wiring.6 times Lighting

When indoor pipe temperature exceeds 55: during heating.

When indoor pipe temperature falls to 6: or below during cooling.

When the discharge temperature exceeds 111:.
When the state with low discharge temperature of which 50.4: or below

in cool and 48.8: or below in heat for 20 minutes.

Abnormal point Detecting method Check points

When a short or open circuit occurs in the defrost thermistor during heat­ing.

3 times

3 times

4 times

7 times

Indication

LED 1

(red)

5 times

Lighting

Lighting

Lighting

Lighting

Lighting

(Yellow)

Lighting

12-4. Trouble criterion of main parts

Part name Check method and criterion

Defrost thermistor
Evaporation / Gas pipe
temperature thermistor

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

These symptoms do not mean any abnor­mality of the product, but check the follow­ing points.

• Air filter clogging.

• Amount of gas.

• Short cycle of indoor / outdoor air flow.

Symptom: Outdoor unit operates

• Check the characteristic of the defrost
temperature thermistor.

Refer to “F” on page 25.

• Check the connector. (CN663)

Normal abnormal

5kΩ ~ 55kΩ Opened or short-circuited

Discharge temperature
thermistor

Compressor

Outdoor fan motor

R. V. coil

Linear expansion valve

Measure the resistance using a tester, after warming up the thermistor by holding by hand.
(Part temperature : 20°C ~40°C)

Normal abnormal

100kΩ ~ 250kΩ Opened or short-circuited

Measure the resistance between terminals using a tester.
(Winding temperature : -10°C ~ 40°C)

Normal abnormal

1Each phase 0.39Ω ~ 0.50Ω Opened or short-circuited

Measure the resistance between lead wires using a tester.
(Part temperature : -10°C ~ 40°C)

WHT - BLK

BLK - YLW
BLK - RED

Normal

208.4Ω ~ 254.8Ω

42.4Ω ~ 51.9Ω

197.7Ω ~ 241.7Ω

abnormal

Opened or

short-circuited

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

Normal abnormal

2.6kΩ ~ 3.3kΩ Opened or short-circuited

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

Lead wire color Normal

Abnormal
WHT - RED
RED - ORN
YLW - BRN

Opened or short-circuited37.4Ω ~ 53.9Ω

BRN - BLU

P Inner protector

21

Outdoor unit does not operate. (LED display: display OFF)

AA

Check of power supply

Start

Check the connecting of main circuit parts .

Turn on power supply

Is there voltage of 230V AC in the
power supply terminal block?

Yes

Is there voltage of 325V DC across the
smoothing capacity?

Yes

Replace the outdoor electronic control
P. C. board.

Outdoor unit does not operate. (LED display: Both LED1 and LED2 lighting)

BB

Check of outdoor unit serial signal

Start

No

No

Check the power supply cable.

Is there voltage of 230V AC across the
input terminal part in the diode module
(DS61)?

Yes

Check the main circuit parts
and replace it.

Replace the noise

No

filter P. C. board

1. Check the indoor unit with referring to the indoor unit service manual.

2. Turn off the power supply of the indoor and outdoor unit and return the indoor/ outdoor unit connecting wire to former
original.

3. Check the connection of indoor/ outdoor unit connecting wire in the outdoor unit terminal block, and check the connection
of the connector (CN601: unit A, CN602: unit B) in the control P. C. board

4. Disconnect the lead wire to the compressor. Turn on the power supply (indoor/ outdoor unit) 3 minutes later,
EMERGENCY OPERATION starts.

Is there voltage from 5V DC - 10V DC between
No. 3 (+) and N (-) in the outdoor terminal block.

Yes

Recheck a connected circumstance of the indoor/ outdoor unit connecting wire.

No

Replace the outdoor electronic control P. C. board.

22

The cooling operation or heating operation does not operate. (LED display: Both LED1 and LED2 lighting)

CC

Check of R. V. coil

• When heating operation does not work.

Start

1. Disconnect the lead wire leading to the compressor.

2. Turn on power supply to the indoor and outdoor unit, three minutes later
EMERGENCY OPERATION (HEAT operation) starts.

Is there voltage of 230V AC between pin1 and
pin 2 at connector CN912?

Yes

Turn off power supply of indoor and outdoor unit.

Disconnect the connector
CN912 in noise filter P. C.
board, and measure the
resistance of R. V. coil to
check the integrity.

Yes

Replace the 4-way valve

• When cooling operation does not work.

Start

1. Disconnect the lead wire leading to the compressor.

2. Turn on power supply to the indoor and outdoor unit, three minutes later
EMERGENCY OPERATION (COOL operation) starts.

No

Replace the R. V. coil

No

1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851) in the outdoor electronic
control P. C. board.

2. Turn on power supply to the indoor and outdoor unit, three
minutes later EMERGENCY OPERATION
(HEAT operation) starts.

Is there voltage 12V DC between
the connector CN851 pin 3 (+)
and pin 4 (-)?

Yes

Replace the noise filter P. C. board.

No

Replace the electronic
control P. C. board.

Is there voltage of 230V AC between pin1 and
pin 2 at connector CN912?

Yes

1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851) in the outdoor electronic
control P. C. board.

2. Turn on power supply to the indoor and outdoor unit, three
minutes later EMERGENCY OPERATION
(COOL operation) starts.

Is there voltage 12V DC between
the connector CN851 pin 3 (+)
and pin 4 (-)? W1

Yes

Replace the outdoor electronic control P. C. board.

No

Replace the noise filter P. C. board.

W1If the connector CN912 is not connected or R. V. coil is open, voltage

occurs between terminals even when the control is OFF.

No

Replace the 4-way valve

23

• When cooling, heat exchanger of non-operating indoor unit frosts.

• When heating, non-operating indoor unit get warm.

DD

Check of LEV

Start

Turn on power supply to the outdoor unit after checking LEV coil is mounted to the
LEV body securely.

LED display:

LED1 LED2

Lighting Lighting

6 time Goes out

Is "click - click" sound heard?
Or, do you feel vibration of the LEV coil with a hand?

No

Disconnect the connector
(CN771: unit A, CN772: unit B), and measure the
resistance of LEV coil to check the integrity.

No

Replace the LEV coil.

• When heating, room does not get warm.

• When cooling, room does not get cool.

EE

Check of inverter/ compressor

Start

Disconnect the lead wire to the compressor at terminals, and turn on power supply to the indoor
and outdoor unit. Three minutes later, EMERGENCY OPERATION starts.

Measure the voltage between
each leading to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Output voltage
COOL: 100V(58Hz), HEAT: 100V (58Hz)
Is voltage output? W1

Yes

Is output balanced?

Yes

Turn off power supply of indoor and outdoor unit,
and measure the compressor winding resistance
between the compressor terminals.
Is there resistance of 0.53" to 0.66" between
the each terminals?

Yes

No

LED display:

W1 • After the outdoor fan starts running, wait for 1 minutes or more before

measuring the voltage.

•The output voltage values in the above table have the tolerance of i20%.

No

Yes

Yes

Replace the outdoor electronic
control P. C. board

No

Normal

Replace the outdoor electronic
control P. C. board

LED1 LED2
Lighting Lighting
Lighting

Twice

Replace the
compressor.

Twice

Goes out

Return the lead wire of compressor to former, and
turn on power supply to indoor and outdoor unit.
Three minutes later EMERGENCY OPERATION starts.

Clarify the causes by counting time until the inverter stops.
0 to 10 seconds: compressor rare short
10 to 60 seconds: compressor lock
60 seconds to 5minutes: refrigerant circuit defective
5 minutes or more: normal

24

• When thermistor is abnormal. (When the LED display is a table below.)

FF

Check of outdoor unit thermistor

Start

Disconnect the connector in the outdoor electronic control P. C. board (see below table),
and measure the resistance of thermistor to check whether the thermistor is normal or not.

Normal

Reconnect the connector (CN661, CN663 and CN664) and disconnect the lead wire leading to the compressor.
Turn on power supply to the indoor and outdoor unit. Three minutes later EMERGENCY OPERATION starts.

Does thermistor operate 10 minutes or more though the
thermistor abnormality is not displayed?

Yes

Normal

Thermistor
Discharge temperature thermistor
Defrost thermistor
Evaporation temperature thermistor
Gas pipe temperature A thermistor
Gas pipe temperature B thermistor
Fin temperature thermistor

• Fan motor does not operate. Or fan motor stops at once after fan motor operate.

GG

Check of outdoor fan motor

Symbol

RT61
RT62
RT63
RT65
RT66
RT67

No

Replace the outdoor electronic
control P. C. board.

Connector, Pin No.
Between CN663 pin3 and pin4
Between CN663 pin1 and pin2
Between CN663 pin5 and pin6
Between CN661 pin1 and pin2
Between CN661 pin3 and pin4
Between CN664 pin1 and pin2

Abnormal

Replace the thermistor

Start

Check the connection of connector (CN851) in the fan motor relay connector and outdoor electronic control P. C. board
at the noise filter P. C. board and connector (CN901) in the noise filter board.

Disconnect the fan motor connector, and measure the resistance of the
fan motor winding to check the winding characteristic.

Normal

1. Disconnect the lead wire leading to the compressor. Turn on power supply to the
indoor and outdoor unit. Three minutes later, EMERGENCY OPERATION starts.

2. Check the voltage between pin 1 and pin 4, pin 1 and pin 5 at the fan motor connector.

Is there voltage of 230V AC?

No

1. Turn off power supply of the indoor and outdoor unit, and disconnect the connector
(CN851).

2. Is the voltage 0V, when the voltage between CN851 pin3 (+), pin7 (-), pin6 (-) are

measured after the power supply is turned on the outdoor unit?

Yes

Is there voltage of 12V DC between CN851 pin3 (+) and pin6 (-), when power supply
turns on the indoor unit and EMERGENCY OPERATION starts in three minutes.

Yes

Replace the noise filter P. C. board

Yes

Abnormal

No

No

Replace the fan motor

Replace the oudtoor
electronic control P. C.
board

25

HH

The other cases

Indoor unit dose not operate. (difference modes)

1

• When you try to run two indoor unit simultaneously, one for cooling and the other for heating, the unit which
transmits signal to the outdoor units earlier decides the operation mode. The other unit indicates as shown in
the figure below.

• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, and
then turn them back ON.

• Though the top of the indoor unit sometimes gets warm, this does not mean malfunction. The reason is that
the refrigerant gas continuously flows into the indoor unit even while it is not operating.

OPERATION INDICATOR

Lighting Flashing

26

-20 -10 0 10 20 30 40

0

10

20

30

40

50

60

70

80

90

100

Temperature(:)

Gas pipe temperature thermistor (RT65,66)

Evaporation temperature thermistor (RT63)

Temperature(:)

Discharge temperature thermistor (RT61)

0 102030405060708090100110120

0

100

200

300

400

500

600

700

0 1020304050607080

0

20

40

60

80

100

120

140

160

180

200

Temperature(:)

Fin temperature thermistor (RT67)

Resistance(k")

Resistance(k")

Resistance(k")

TEST POINT DIAGRAM AND VOLTAGE
MXZ-18TV

-

MXZ-18TV -

,

E2E1

Outdoor Electronic control P.C.board

Linear expansion valve (LEV)

12V DC pulse wave

Linear expansion valve (LEV)

12V DC pulse wave

325V DC

(

Gas pipe temperature Athermistor (RT65)

(

Gas pipe temperature B thermistor (RT66)

Defrost temperature thermistor (RT62)

(((

Discharge temperature thermistor (RT61)

Evaporation temperature thermistor (RT63)

(

Fin temperature thermistor (RT67)

R.V. coil 12V DC

Current Limit Relay 12V DC

Outdoor fan Hi 12V DC

Outdoor fan Lo 12V DC

Room A

(

Room B

(

LED monitor
indication (LED 1)

LED monitor
indication (LED 2)

Serial signal Room B
5 ~ 10V DC

Serial signal Room A
5 ~ 10V DC

27

Noise filter P.C.board

E1

MXZ-18TV

230V AC 50Hz Input

Outdoor Fan
Fan speed “Hi”
230V AC

-

Outdoor Fan
Fan speed “Lo”
230V AC

230V AC 50Hz Output

Reversing valve
230V AC

MXZ-18TV -

230V AC 50Hz Input

Outdoor Fan
Fan speed “Lo”
230V AC

E2

230V AC 50Hz Output

Outdoor Fan
Fan speed “Hi”
230V AC

FUSE(F911)AC250V 1A R.V.coil 230V AC FUSE(F912)AC250V 3.15A

28

13

DISASSEMBLY INSTRUCTIONS

MXZ-18TV - ,MXZ-18TV -

E2E1

OUTDOOR UNIT

OPERATING PROCEDURE

1. Removing the top panel ~ back panel

(1) Remove the screws fixing the top panel and remove it.

(Photo 1)

(2) Remove the screw fixing the service panel, next pull down

the service panel and remove it from the cabinet. (Photo 2)
(3) Remove the screws fixing the front cover and remove it.
(4) Remove the inside and outside connection electric wire.
(5) Remove the screws fixing the back panel and remove it.

Photo 2

4 Hooks

2. Removing the inverter assembly

(1) Remove the top panel, front panel, and service panel.
(2) Remove the inside and outside connection electric wire, next

remove the back panel.
(3) Disconnect the connector of outdoor fan motor (CN911),

R.V. coil (CN912) in the noise filter P.C. board.

Disconnect the connector of discharge / defrost / evapora-

tion temperature thermistor (CN663), gas pipe temperature

thermistor (CN661), LEV A(CN771), LEV B (CN772) in the

electronic control P.C. board.
(4) Remove the compressor relay connector. (Photo 3)
(5) Remove the two screws fixing the relay panel, and remove

the inverter assembly. (Photo 3)

Photo 1

Front panel

Photo 3

PHOTOS

Top panel

Back panel

Screw of the
service panel

Service panel

Screw of the

relay panel

3. Removing the inverter P.C. board

(1) Remove the top panel, front panel, and service panel.
(2) Remove all the connectors the lead wire and the earth wire

on the electronic control P.C board.
(3) Remove the compressor relay connector.
(4) Remove the two screws fixing the heat sink, and pull up the

inverter P.C. board.
(5) Remove the screws fixing the transistor module.
(6) Remove the inverter P.C. board.

4. Removing the noise filter

(1) Remove the top panel, front cover, and service panel.
(2) Remove all the connectors the lead wire and earth wire on

the electronic control P.C. board.
(3) Remove the two hooks, then remove the noise filter P.C.

board.

29

Photo 4

Inverter
P.C. board

Compressor connector

Screws of
the heat sink

Noise filter
P.C. board

Hooks

OPERATING PROCEDURE

5. Removing the 4-way coil

(1) Remove the top panel, front cover and service panel.
(2) Remove the inside and outside connection electric wire, next

remove the back panel.

(3) Remove 4-way coil and disconnect the noise filter P.C. board

connectors CN912

6. Defrost, Discharge temperature thermistor

(1) Remove the top panel, front cover, service panel.
(2) Remove the inside and outside connection electric wire, next

remove the back panel.
(3) Remove the connector CN663 on inverter P.C. board.
(4) Remove the defrost thermistor and remove the discharge

temperature thermistor on the compressor. (Photo 5, 6)

7. Fin temperature thermistor

(1) Remove the top panel, front cover, service panel.
(2) Remove the inside and outside connection electric wire, next

remove the back panel.
(3) Remove all the connectors the lead wire and the earth wire

on the electronic control P.C. board.
(4) Remove the compressor relay connector. (Photo 3)
(5) Remove the two screws fixing the heat sink, and pull up the

inverter P.C. board. (Photo 4)
(6) Remove the screws fixing the transistor module. (Photo 4)
(7) Remove the screws the fin temperature thermistor, and

remove it. (Photo 7)

PHOTOS

Photo 5

Discharge temperature thermistor

Photo 6

8. Removing the fan motor

(1) Remove the top panel, front cover.
(2) Remove the fan motor connectors (CN911) on the noise fil-

ter P.C. board.
(3) Remove the propeller fan.
(4) Remove the screws fixing the fan motor and remove it.

Photo 7

Photo 8

Fan motor

Defrost thermistor

Inverter board

Fin temperature
thermistor

Screws of fan motor

30

Propeller
fan

OPERATING PROCEDURE PHOTOS

9. Remove the compressor

(1) Remove the top panel, front cover, service panel.
(2) Remove the inside and outside connection electric wire,

next remove the back panel.
(3) Remove the inverter assembly.
(4) Can have the service of compression, 4-way and other

refrigerant circuit..

(5) Remove then the part (four places) which welds it when

you leave 4-way. (Photo 9)

Photo 9

Welded part

31

14

1
2
3
4
5

6
7
8

9
10
11
12
13
14
15
16

FIN TEMPERATURE THERMISTOR
DIODE STACK
REACTOR
CONNECTOR POST ASSY
NOISE FILTER P.C. BOARD
NOISE FILTER P.C. BOARD
FUSE
THERMISTOR SET
GAS PIPE TEMPERATURE THERMISTOR SET
R.V. COIL
TERMINAL BED
TERMINAL BED
ELECTRONIC CONTROL P.C. BOARD
POWER FACTOR CAPACITOR
SMOOTHING CAPACITOR
FUSE
FUSE&VARISTOR

RT67

DS61, DS62

L

RT61,RT62,RT63

RT66, RT65

21S4

TB2
TB1

C61
C62

F911

F912,NR63

1
2
1
1
1

1
1
1
1
1
1
1
1
1
1

No. Parts Name

Symbol

in Wiring

Diagram

Parts No.

Q'ty / unit

MXZ-18TV-

Remarks

20A

EVAOPRATION
DISCHARGE, DEFROST
GAS PIPE TEMPERATURE
THREMISTOR

1A 250V

3.15A 250V

E1

T2W E87 308
T2W E45 447
M21 68K 337
T2W E87 471
T2W E87 424
T2W G04 424
T2W E99 382
T2W E87 309
T2W E87 306
T2W E87 389
T2W E64 376
T2W E75 375
T2W E87 451
T2W E45 357
T2W E75 356
T2W E66 382
T2W E99 313

MXZ-18TV-

E2

1
2
1
1

1
1
1
1
1
1
1
1
1
1
1
1

PARTS LIST

14-1. OUTDOOR UNIT FUNCTIONAL PARTS
MXZ-18TV ­MXZ-18TV -

E1
E2

1314

1

2

12

11

3

4

5 6

7 8

10

9

32

14-2. OUTDOOR UNIT STRUCTURAL PARTS
MXZ-18TV ­MXZ-18TV -

E1
E2

14

13

15

1

16
17

2

18

3 4 5 6 7 8 9

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

No. Parts Name

Parts No.

T2W E87 232

1

T2W E87 521

2

M21 68N 290

3

T92 501 280

4

T2W E87 646

5

M21 21J 662

6

M21 00A 661

7

T2W E87 531

8

T2W E87 245

9

T2W G04 961

10

T2W E87 293

11

T2W E87 630

12

M21 68K 523

13

M21 68N 297

14

T2W E87 515

15

T2W E87 301

16

M21 68N 501

17

M21 61G 972

18

T2W E87 645

19

M21 PA2 642

20

FRONT PANEL ASSEMBLY
GRILLE
BASE ASSEMBL Y
COMPRESSOR
EXPANSION VALVE
STOP VALVE (LIQUID)
STOP VALVE (GAS)
BACK PANEL
SERVICE PANEL ASSEMBLY
4-WAY VALVE
SEPARATOR
OUTDOOR HEAT EXCHANGER
CONDENSER NET
TOP PANEL
MOTOR SUPPORT
OUTDOOR FAN MOTOR
PROPELLER FAN
PROPELLER FAN NUT
LEV ASSEMBL Y
STRAINER

Symbol

in Wiring

Diagram

LEV

MXZ-18TV-

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

12

Q'ty / unit

E1

MXZ-18TV-

11

10

E2

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

Remarks

SHV-130FEA

RA6V35-

33

B

A

C

15

OPTIONAL PARTS

15-1. Different-diameter pipe

MXZ-18TV

Model name

Model code

Connected pipes

diameter (mm)

Length

A

Length

B

Length

Unit : mm (inch)

C

For different­diameter
pipes

MAC-454JP

51H-454

{9.52 — {12.7
(3/8) (1/2)

{9.52

(3/8)

{12.7

(1/2)

69

34

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

CC

Copyright 2001 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD.
Distributed in Dec. 2002. No.OB280 REVISED EDITION-A 16
Reprinted in Dec. 2001 No.OB280 5
Reprinted in Dec. 2001 No.OB280 50
Distributed in Mar. 2001. No.OB280 49
Made in Japan

New publication, effective Dec. 2002
Specifications subject to change without notice.