Mitsubishi Electric MSH-18NV, MUH-18NV Service Manual

SERVICE MANUAL

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

CONTENTS

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

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

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

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

5. WIRING DIAGRAM ············································6

6. REFRIGERANT SYSTEM DIAGRAM················7

7. PERFORMANCE CURVES································8

8. MICROPROCESSOR CONTROL ····················10

9. SERVICE FUNCTIONS ····································19

10. TROUBLESHOOTING······································21

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

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

13. OPTIONAL PARTS···········································37

Wireless type Model

MSH-18NV -

(WH)

· MUH-18NV -

E4E4

No. OB229

REVISED EDITION-A

MSH-18NV -

•Refer to the Service Manual OB185 REVISED EDITION C when MSH-18NV- is connected with MXZ-32NV- or MXZ-32NV- as multi system units.

•Refer to the Service Manual OB227 REVISED EDITION-B when MSH-18NV- is connected with MXZ-32RV- as multi system units.

E2E1

Revision:

●Information for connecting MSH-18NV- with MXZ-32RV- was described.

●TROUBLESHOOTING has been modified.

PART NAMES AND FUNCTIONS

INDOOR UNIT

(When the grille is open)

Front panel

MSH-18NV -

TECHNICAL CHANGES

MSH-18NV- became possible the connection to MXZ-32RV- as multi system units.

E1E4

Drainage hose

Piping

Air inlet

Air outlet

Drain outlet

(back and side)

OUTDOOR UNIT

MUH-18NV -

TEMPERATURE buttons

VANE CONTROL button

SWING button

OFF-TIMER button

RESET button

Signal transmitting section

Operation display section

OPERATE/STOP (ON/OFF)button

OPERATION SELECT button

FAN SPEED CONTROL button

SLEEP button

ON-TIMER button

CLOCK SET button

HR. button

MIN. button

(TIMER SET button)

MSH-18NV -

REMOTE CONTROLLER

Capacity

Electrical data

Compressor

Indoor

fan motor

Outdoor

fan motor

Dimensions

Weight

Special remarks

Model

Function

Power supply

Coefficient of performance(C.O.P)

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

Model Output Winding resistance(at20:) Model Winding resistance(at20:) Model Winding resistance(at20:)

Indoor unit

Outdoor unit

Indoor unit Outdoor unit Air direction Sound level (Hi) Fan speed (Hi) Fan speed regulator Refrigerant filling capacity(R-22) Refrigerating oil (Model)

Thermistor

Width Height Depth Width Height Depth

Indoor unit Outdoor unit Indoor unit Outdoor unit Indoor unit Outdoor unit

RT11(at25:) RT12(at25:) RT61(at0:)

R/h

K /h

A A

A(kW)

A A A



"

mm mm mm mm mm mm

kg kg

dB rpm rpm

cc k" k" k"

MSH-18NV -

Single phase,220-240V,50Hz

INDOOR 756 OUTDOOR 2142-2244

52-58

INDOOR 0.25 OUTDOOR 0.39

PH-36VPET

1600

C-R1.03 C-S2.04

RA4V27-EA or EF

WHT-BLK183.8 BLK-RED250.5

RA6V50-OF or OG

WHT-BLK116.4 BLK-RED111.0

1,015

320 190 850 605 290

14 54

5 42 52

1,180

810-845

1.65

900 (MS32N1)

10 10

33.18

Cooling

5.1

2.5

9.4-9.2

2,030-2,120

—

98-96

8.76-8.56

2.51-2.41

Heating

5.4 —

9.2-9.0

1,980-2,070

—

98-96

8.56-8.36

2.73-2.61

WMSH-18NV- E4 (INDOOR UNIT)

Cooling Heating

Single phase,220-240V,50Hz

— —

—

756

0.28 60 —

97-89

— —

0.25 — — — —

RA4V27-EA or EF

WHT-BLK183.8 BLK-RED250.5

— —

1,015

320 190

— — — 14 —

5 42 —

1,180

—

4 — — — 10 10 —

wRefer to the Service Manual OB185 REVISED EDITION C when MSH-18NV- is connected with

MXZ-32NV- or MXZ-32NV- as multi system units.

wRefer to the Service Manual OB227 REVISED EDITION-B when MSH-18NV- is connected with

MXZ-32RV- as multi system units.

E2E1

SPECIFICATION

NOTE:Test conditions

Cooling : Indoor DB27°C / WB19°C Heating : Indoor DB20°C /WB15.5°C

Outdoor DB35°C / WB24°C Outdoor DB7°C / WB6°C

OUTLINES AND DIMENSIONS

Unit: mm

OUTDOOR UNIT

MSH-18NV -

MUH-18NV -

INDOOR UNIT

3 297

450 450

352438

254

150 648 217

5190

995

19077550

320

1015

17.5

160

4holes 11✕20

Indoor unit

Installation plate

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

Wall hole [75

Installation plate

Liquid line [8-0.5m Gas line [12-0.43m Insulation [50 O.D

[28 I.D

Insulation [28

Drain hose [16

Air out

{

Air in

If the right/left sides or back side is vacant, the front has only to be 50cm unobstructed.

If the front or right/left sides

are vacant, the top has only

to be 10cm unobstructed.

Drainage 3holes [33

Air out

Air in

Service panel

Liquid refrigerant pipe joint

Refregerant pipe (flared) [6.35

Gas refregerant pipe joint

Refregerant pipe (flared) [15.88

35-

30-

100

161

157

850

500

183

292

605

248

350

290

310

345

355

Drainage hole [16.2

MSH-18NV -

MUH-18NV -

MODEL WIRING DIAGRAM

INDOOR UNIT

OUTDOOR UNIT

CIRCUIT BREAKER

12VDC

50Hz

CORD

POWER SUPPLY

~/N 220-240V

F11

NR11

TRANS

HIC1

12VDC 220-240V~

DSAR

BRN

GRN/YLW

LD1

DISPLAY P.C.BOARD

RECEIVER P.C.BOARD

101

102

CN CN

TO OUTDOOR UNIT CONNECTING

BLU

GRN/YLW

151

BLU

ELECTRONIC CONTROL P.C BOARD

REMOTE CONTROLLER

BLU

RED

2 1

F12

WHT

BRN

L 3

CN201

CN211

121

112

RT11

BRN YLW

RED

GRY WHT

BLK

RT12

52C

IC141

C11

FOR MULTI SYSTEM

TO OUTDOOR UNIT CONNECTING

111

❈ ❈

❈

SYMBOL

RT12

52C

SYMBOL

HIC1

MV NR11 RT11

SYMBOL

C11

DSAR

F11 F12

IC141

NAME

NAME NAME INDOOR FAN CAPACITOR SURGE ABSORBER FUSE(3.15A) THERMAL FUSE(93:) HYBRID IC

DC/DC CONVERTER INDOOR FAN MOTOR(INNER FUSE) VANE MOTOR VARISTOR ROOM TEMPERATURE THERMIST OR

INDOOR COIL THERMISTOR TERMINAL BLOCK CONTACTOR

CN720

52C

X62

21S4

CN721

SR61

WHT

VLT

COM

52C

TAB21

DSAR

ORN

WHT

RED

WHT

BLU

RED

BLK

CN730

C65

DEICER P.C.BOARD

RT61

F61

IC881

X62

CN711

BLK

TRANS

TAB20

BLK

FROM

INDOOR UNIT

CONNECTING

GRN/YLW

12VDC

220-240V~

2 3 4

BLK

CN661

NR61

❈

NAME

NAME NAME

SYMBOL

C65

DSAR

F61

IC881

SYMBOL

X62

21S4

52C

SYMBOL

MF NR61 RT61 SR61

COMPRESSOR CAPACITOR OUTDOOR FAN CAPACITOR SURGE ABSORBER FUSE(2A) DC/DC CONVERTER

COMPRESSOR(INNER THERMOSTAT) OUTDOOR FAN MOTOR(INNER THERMOSTAT) VARISTOR DEFROST THERMISTOR SOLID STATE RELAY

TERMINAL BLOCK REVERSING VALVE COIL RELAY REVERSING VALVE COIL CONTACTOR

NOTE:1. For the outdoor 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

WIRING DIAGRAM

Sleeve

Locking lever

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

2. Symbols below indicate.

: Terminal block, : Connector

3. “❈”show the terminals with a lock mechanism, so they cannot be removed when you pull

the lead wire. Be sure to pull the wire by pushing the locking lever (projected part) of the terminal with a finger.

1.Slide the sleeve.

2.Pull the wire while pushing the locking lever.

REFRIGERANT SYSTEM DIAGRAM

MSH-18NV -

MUH-18NV -

INDOOR UNIT

OUTDOOR UNIT

Indoor heat exchanger

Room temperature thermistor RT11

Refrigerant pipe [15.88 (Option)

Flared connection

Indoor coil thermistor RT12

Refrigerant pipe[ 6.35 (Option)

Stop valve

Strainer

Check valve

Capillary tube

[3.0o[2.0o500

Capillary tube

[3.0o[1.6o750

(2 pcs)

Compressor

Accumulator

Stop valve (with service port)

Muffler

Outdoor heat exchanger

Defrost thermistor RT61

Reversing valve coil (4-way valve coil) Heating ON Cooling OFF

Refrigerant flow in cooling Refrigerant flow in heating

(with heat insulator)

Strainer

Distributor

Reversing valve (4- way valve)

Model

Piping size O.D : mm Length of connecting pipe : m

Refrigerant piping

Max. length : m

Indoor unit

Gas 0.43

Liquid 0.5

Gas

15.88

Liquid

6.35

Outdoor unit

Gas 0

Liquid 0

MSH-18NV - E4

Indoor unit

wMax. Height

difference: 5m

Refrigerant Piping Max. Length

w Height difference should be within 5m regardless of which unit, indoor or outdoor position is high.

Outdoor unit

Model

MSH-18NV -

Refrigerant piping length (one way)

Outdoor unit precharged

(up to 7m)

1650

15m

400

10m

150

MAX. HEIGHT DIFFERENCE

ADDITIONAL REFRIGERANT CHARGE(R-22 : g)

MAX. REFRIGERANT PIPING LENGTH

Calculation : Xg=50g/m ✕ (A-7)m

(with heat insulator)

11.2

7.2

8.2

9.1

10.1

12.2

MSH-18NV - E4

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

Rated voltage : ±10% (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 (4) Total input: W (5) Indoor intake air dry-bulb temperature : °CDB (6) Outdoor intake air wet-bulb temperature : °CWB (7) Total input : W

Indoor air wet/dry-bulb temperature difference on the left side of the chart on this page and next page 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

}

Cooling

Heating

PERFORMANCE CURVES

Wet-and dry-bulb thermometers

MSH-18NV -

28.0

25.9

23.7

21.6

19.4

17.2

15.1

12.9

MSH-18NV - E4

NOTE:The above curves are for the heating operation without any frost.

OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT COOL operation

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

Air flow should be set at MAX.

Dry-bulb temperature

Relative humidity(%)

30 70

The unit of pressure has been changed to MPa on the international system of units(SI unit system). The conversion factor is : 1(MPa • G) =10.2(kgf/ff• G)

15 20

25 60

30 70(%)

35(:)

0.3

0.4

0.5

0.6

0.7

18 32

220V/240V

15 20

25 60

30 70(%)

35(:)

18 32

220V/240V

MUH-18NV -

Outdoor low pressure

Ambient temperature(˚C) Ambient humidity(%)

Outdoor unit current (A)

(kgf/F•G)(MPa•G)

HEAT operation

Condition indoor:Dry bulb temperature 20.0°C

Wet bulb temperature 14.5°C

Outdoor:Dry bulb temperature 7,15,20°C

Wet bulb temperature 6,12,14.5°C

MUH-18NV -

5 10152025

220V/240V

(:)

Outdoor unit current (A)

Ambient temperature(˚C)

MICROPROCESSOR CONTROL

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

8-1. “I FEEL CONTROL” ( ) OPERATION

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

controller. Operation Indicator lamp of the indoor unit turns on with a beep tone.

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

CONTROL”( ). Then a beep tone is heard.

(3) The operation mode is determined by the room

temperature at start-up of the operation.

lighting not lighting

Approx. 2 :  or more

Difference betweeen set temperature and room temperature

Approx. 2 :  or less

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

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

Operation state

Indication

Operation Indicator

Operation Indicator lamp

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

INDOOR UNIT DISPLAY SECTION

WIRELESS REMOTE CONTROLLER

Example Previous operation

COOL mode of “I FEEL CONTROL” or COOL mode

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

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

• When the system is stopped with the OPERATE/STOP (ON/OFF) 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.

Mode

COOL mode of

"I FEEL CONTROL"

DRY mode of

"I FEEL CONTROL"

HEAT mode of

"I FEEL CONTROL"

Initial room temperature

25: or more

23:to 25:

less than 23:

Example

Previous operation

COOL mode of “I FEEL CONTROL”

or COOL mode

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

Restart

COOL mode of “I FEEL CONTROL”

Restart

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

MSH-18NV -

Model

COOL mode of

"I FEEL CONTROL"

DRY mode of

"I FEEL CONTROL"

HEAT mode of

"I FEEL CONTROL"

Initial room temperature Initial set temperature

26:

26: or more

25: to 26:

less than 23:

23: to 25:

24:

Initial room temperature minus 2: Initial room temperature minus 2:

❈1

❈1 When the system is restarted with the remote controller, the system operates with the previous set temperature

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

(5) TEMPERATURES buttons

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

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

• Fuzzy control

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

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

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

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

1. Indoor fan speed control

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

Initial temperature difference Fan Speed

Room temperature minus set temperature : 2 degrees or more

····························Hi

Room temperature minus set temperature : Between 1 and 2 degrees

·················Me

Room temperature minus set temperature : less than 1 degree

····························

— COOL mode of “I FEEL CONTROL” —

Difference between room temperature and set temperature during operation.

1deg. 1.7deg.

2deg. 4deg.

2. Coil frost prevention

① Temperature control

When the indoor coil thermistor RT12 reads 3°C or below, the coil frost prevention mode starts immediately. However, the coil frost prevention doesn’t work for 5 minutes since the compressor has started. The indoor fan operates at the set speed and the compressor stops for 5 minutes. After that, if RT12 still reads below 3°C this mode prolonged until the RT12 reads over 3°C.

Operation time chart

Example

3. Coil frost prevention

• The operation is as same as coil frost prevention during COOL mode of “I FEEL CONTROL”.

• Indoor fan operates at the set speed and the compressor stops for 5 minutes, because protection(Coil frost prevention) has the priority. However, when coil frost prevention works while the compressor is not operating, it’s speed becomes Lo.

Thermostat

Indoor fan

Outdoor fan Compressor

8 min.

1 min.

4 min.

3 min.

OFF

Compressor Outdoor fan

OFF

(continuously at set speed)

Indoor fan

OFF

Operation chart

Example

—DRY mode of “I FEEL CONTROL”—

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

1. Indoor fan speed control

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

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

Compressor operates by room temperature control and time control. Set temperature is controlled to fall 2°C from initial room temperature. Indoor fan and outdoor fan operate in the same cycle as the compressor.

•When the room temperature is 23°C or over: When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF. When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

•When the room temperature is under 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.

OFF

② Time control

When the three conditions as follows have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes. a. Compressor has been continuously operating. b. Indoor fan speed is Lo or Me. 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 Hi or the room temperature exceeds 26°C.However, when two of the above conditions (b.and c.) are satisfied again.Time accumulation is resumed.

+ 26 hidden pages

Mitsubishi Electric MSH-18NV, MUH-18NV Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual