Mitsubishi Electric MS-A18WV Service Manual Download Page 1

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SERVICE MANUAL

CONTENTS

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

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

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

4. NOISE CRITERIA CURVES ·······························5

5. OUTLINES AND DIMENSIONS ·························6

6. WIRING DIAGRAM ············································7

7. REFRIGERANT SYSTEM DIAGRAM ················8

8. MICROPROCESSOR CONTROL ······················9

9. SERVICE FUNCTIONS ····································17

10. TROUBLESHOOTING······································19

11. DISASSEMBLY INSTRUCTIONS ·····················27

12. PARTS LIST······················································29

13. OPTIONAL PARTS···········································31

Wireless type

Models

MS-A18WV -

(WH)

MS-A24WV -

(WH)

MS-A30WV -

(WH)

No. OB325

SPLIT-TYPE, AIR CONDITIONERS

MS-A18WV -
MS-A24WV -
MS-A30WV -

NOTE:
This service manual describes technical data of the indoor units.
As for outdoor units MU-A18WV-

, MU-A24WV-

and MU-A30WV-

, refer to service manual

OB326.

Indication of model name

OB325-1.qxp 03.12.3 1:03 PM Page 1

Summary of Contents for MS-A18WV

Page 1: ...ICE FUNCTIONS 17 10 TROUBLESHOOTING 19 11 DISASSEMBLY INSTRUCTIONS 27 12 PARTS LIST 29 13 OPTIONAL PARTS 31 Wireless type Models MS A18WV WH MS A24WV WH MS A30WV WH E1 E1 E1 No OB325 SPLIT TYPE AIR CONDITIONERS MS A18WV MS A24WV MS A30WV E1 E1 E1 NOTE This service manual describes technical data of the indoor units As for outdoor units MU A18WV MU A24WV and MU A30WV refer to service manual OB326 E...

Page 2: ...8 6 35 7 Air filter has changed to catechin air filter MS 24RV MS A24WV 1 Indoor unit model has changed 2 Rated voltage has changed 220V 240V 230V 3 Remote controller has changed LONG MODE and WIDE MODE have been added 4 Indoor fan motor has changed RA4V27 EE RC4V32 AA 5 Indoor heat exchanger has changed 6 Diameter of connect pipe has changed Liquid 8 6 35 7 Air filter has changed to catechin air ...

Page 3: ...en the front lid Signal transmitting section Operation display section OPERATE STOP ON OFF button TEMPERATURE buttons OPERATION SELECT button FAN SPEED CONTROL button OFF TIMER button HR button MIN button TIME SET button ON TIMER button RESET button ECONO COOL button VANE button Horizontal vane button CLOCK SET button LONG button WIDE VANE button Vertical vane button Indication of remote controlle...

Page 4: ... Fan motor Special remarks Capacity w w w w w w w w w w w w w w w w w w NOTE 1 Test conditions are based on JIS C 9612 Cooling Indoor DB27 C WB19 C Outdoor DB35 C WB 24 C Indoor Outdoor piping length 5m 2 Remote controller model KP0B and KG1D are the same in terms of specification w Reference value Indoor model Function Power supply Air flow High Med Low Power outlet Running current Power input Au...

Page 5: ... NC 30 NC 20 NC 70 BAND CENTER FREQUENCIES Hz Test conditions Cooling Dry bulb temperature 27 Wet bulb temperature 19 APPROXIMATE THRESHOLD OF HEARING FOR CONTINUOUS NOISE 42 SPL dB A LINE High FAN SPEED OCTAVE BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR 90 80 70 60 50 40 30 20 10 63 125 250 500 1000 2000 4000 8000 NC 60 NC 50 NC 40 NC 30 NC 20 NC 70 BAND CENTER FREQUENCIES Hz Test conditions...

Page 6: ...d part O D Liquid line 6 35 0 5m Gas line 12 0 43m Insulation 50 O D 32 I D Installation plate Wall hole 75 Wireless remote controller Installation plate Indoor unit Liquid line 9 52 0 5m Gas line 12 0 43m Insulation 50 O D 32 I D for MS A18 A24WV for MS A30WV Power supply cord Lead to right 2 0m Lead to left 1 0m INDOOR UNIT MS A18WV MS A24WV MS A30WV E1 E1 E1 Unit mm ...

Page 7: ...B NAME INDOOR COIL THERMISTOR SOLID STATE RELAY TERMINAL BLOCK MF 1 2 3 4 5 6 PE CIRCUIT BREAKER POWER SUPPLY CORD N 230V 50Hz INDOOR UNIT 12V TO OUTDOOR UNIT CONNECTING BRN BLU GRN YLW BLK GRY YLW BRN WHT RED MF 3 SR141 4 3 1 CN 121 C11 HIC1 TRANS MV1 RT13 4 3 2 1 CN112 151 CN MV2 15 RT12 RT11 111 CN CN211 NR11 ELECTRONIC CONTROL P C BOARD F11 3 N L BRN 1 2 3 CN201 MV2 BLU RED CN 101 CN 102 DISPL...

Page 8: ...frigerant flow in cooling MS A18WV E1 INDOOR UNIT Indoor heat exchanger Room temperature thermistor RT11 Refrigerant pipe 12 7 with heat insulator Flared connection Flared connection Indoor coil thermistor RT12 Refrigerant pipe 6 35 with heat insulator Distributor MS A24WV E1 INDOOR UNIT Indoor heat exchanger Room temperature thermistor RT11 Refrigerant pipe 15 88 with heat insulator Flared connec...

Page 9: ...ANE MODE ECONO COOL STOP START HR MIN WIDE VANE LONG I FEEL COOL DRY PM CLOCK AM RESET CLOCK OPERATION SELECT button FAN SPEED CONTROL button OFF TIMER button HR button MIN button TIME SET button ON TIMER button RESET button ECONO COOL button VANE button Horizontal vane button CLOCK SET button LONG button WIDE VANE button Vertical vane button ON OFF TOO COOL PM AM TOO WARM FAN Signal transmitting ...

Page 10: ...temperature minus 2 1 4 The initial set temperature is decided by the initial room temperature 1 When the system is restarted with the remote controller the system operates with the previous set temperature regard less of room temperature at restart The set temperature is calculated by the previous set temperature 5 TEMPERATURE buttons In I FEEL CONTROL mode set temperature is decided by the micro...

Page 11: ... 3 C or below MS A24WV RT12 or RT13 reads 1 C or below MS A30WV 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 0 C MS A18WV 3 C MS A24WV RT12 or RT13 still reads below 1 C MS A30WV this ...

Page 12: ...r operations are same as DRY mode of I FEEL CONTROL 4 DRY operation will not function when the room temperature is 13 C or below 8 4 FAN d OPERATION 1 Press OPERATE STOP ON OFF button OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone 2 Select FAN mode with the OPERATION SELECT button 3 Select the desired fan speed When AUTO it becomes Low Only indoor fan operates Outdoor unit d...

Page 13: ...speed and angle of the motor are controlled by pulse signals approx 12V transmitted from indoor microprocessor 2 The horizontal vane angle and mode changes as follows by pressing the VANE button In COOL and DRY operation In FAN operation Vane angle is fixed to Angle 1 Vane angle is fixed to Angle 4 3 Positioning The vane is once pressed to the vane stopper below to confirm the standard position an...

Page 14: ...elled when the ECONO COOL button is pressed once again or VANE button is pressed or LONG button is pressed or change to other operation mode NOTE ECONO COOL operation does not work in COOL mode of I FEEL CONTROL SWING operation w 1 Tp Value of RT12 MS A18 A24WV Minimum value of indoor coil thermistor main RT12 and indoor coil thermistor sub RT13 MS A30WV In swing operation of ECONO COOL operation ...

Page 15: ... fan speed becomes faster than setting fan speed on the remote controller even when or is selected 8 7 TIMER OPERATION 1 How to set the timer 1 Press OPERATE STOP ON OFF button to start the air conditioner 2 Check that the current time is set correctly NOTE Timer operation will not work without setting the current time Initially AM0 00 blinks at the current time display of TIME MONITOR so set the ...

Page 16: ...eed The coil frost prevention works even in emergency operation In the test run or emergency operation the horizontal vane operates in VANE AUTO mode Emergency operation continues until the EMERGENCY OPERATION switch is pressed again or the unit receives any signal from the remote controller In case of latter normal operation will start NOTE Do not press the EMERGENCY OPERATION switch during norma...

Page 17: ... time will be shortened as follows Set time 1 minute 1 second Set time 3 minute 3 second It takes 3 minutes for the compressor to start operation However the starting time is shortened by short circuit of JPG and JPS The P C board has the print J1 and J2 Solder J1 and J2 according to the number of indoor unit as shown in Table 1 After modification press the RESET button MS A18WV MS A24WV MS A30WV ...

Page 18: ...usly at restart Therefore the special counter measures are required to prevent the main voltage drop or the rush of the starting current by adding to the system that allows the units to start one by one When the indoor unit is controlled with the remote controller the operation mode set temperature and the fan speed are memorized by the indoor electronic control P C board The AUTO RESTART FUNCTION...

Page 19: ... unit is flashing on and off to indicate an abnormality To make sure check how many times the abnormality indication is flashing on and off before starting service work 2 Before servicing check that the connector and terminal are connected properly 3 If the electronic control P C board is supposed to be defective check the copper foil pattern for disconnection and the components for bursting and d...

Page 20: ...coil thermistor 3 time flash Cause Indoor unit Trouble of indoor fan motor MU A30WV 6 time flash Cause Outdoor unit Trouble of thermistor in outdoor unit MU A30WV 7 time flash Cause Outdoor unit Trouble of outdoor control system Refer to D How to check mis wiring When outdoor unit doesn t work on page 25 Check room temperature thermistor and indoor coil thermis tor Refer to Test point diagram and ...

Page 21: ...r to service manual OB326 Refer to D How to check mis wiring on page 25 3 Indoor fan motor 7 MU A30WV Low discharge tempera ture protection When discharge temperature has been 50 or less on cool operation 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 op...

Page 22: ...T13 sub Horizontal vane motor MV1 Vertical vane motor MV2 Motor part Sensor part Measure the resistance between the terminals with a tester Part temperature 10 C 30 C Color of lead wire BRN YLW YLW GRY Abnormal Remain 0V or 5V Normal 4 5 5 5V Measure the voltage power ON When fan revolved one time 0V 5V 0V Approx Normal 282 306 Abnormal Open or short circuit Measure the resistance between the term...

Page 23: ... voltage between receiver P C board connector CN301 No 2 and No 1 when the remote controller button is pressed Is the voltage approx 4V DC Replace the indoor electronic control P C board Replace the receiver P C board Replace the remote controller Reinstall the unit away from lights Attach a filter on receiving part Yes 0 or No others Yes No Yes No Switch on the remote controller Is LCD display on...

Page 24: ...t Replace the varistor Yes Turn OFF the power supply Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P C board and turn ON the power supply No No Does the unit operate with the remote controller Does the OPERATION INDICATOR lamp light up by pressing the EMERGENCY OPERATION switch Yes No Be sure to check both resistance Turn OFF the power su...

Page 25: ... Make them sure Replace the indoor electronic control P C board Is there 230V AC between L N on the outdoor terminal block No Check the outdoor power supply and connection of wiring Yes No Replace the deicer P C board Yes No Make the wiring between CN730 on the deicer P C board and outdoor terminal block correct Replace the deicer P C board Yes Is there 5V DC between J101 J401 MU A30WV on the deic...

Page 26: ... DC Indoor coil thermistor RT12 main Timer short mode point JPS JPG Refer to page 17 Emergency operation switch 12V DC Indoor coil thermistor RT12 main RT13 sub Room temperature thermistor RT11 Resistance k Room temperature ther mistor RT11 Release of Auto restart function Solder jumper wire to JR07 Refer to page 18 MS A30WV Indoor coil thermistor RT13 sub R132 Receiver P C board ...

Page 27: ...ps of the front panel Remove the screws 2 Pull the panel down to your side slightly and unhook the catches at the top Photo 1 Photo 2 Front panel Screw of the V A clamp Indoor electronic control P C board Vane motor connector Fan motor connectors Screws of the ground wire Screws Screw of the electri cal cover R L holder Screw of the termi nal block Receiver P C board 2 Removing the electronic cont...

Page 28: ... drain hose from the nozzle assembly and remove the nozzle assembly 6 Remove the screws of the vane motor and disconnect the connector 7 Remove the vane motor Screws fixing the fan motor 5 Removing the line flow fan and the indoor fan motor 1 Remove the front panel Refer to 1 2 Remove the electrical box Refer to 3 3 Pull out the drain hose from the nozzle assembly and remove the nozzle assembly 4 ...

Page 29: ...ng Diagram Q ty unit Including No 4 5 6 4PCS SET 3PCS SET Remarks Part No No Part Name 1 2 3 4 5 6 7 8 9 1 1 1 4 3 1 2 1 1 1 1 1 4 3 1 2 1 1 1 1 1 4 3 1 2 1 1 12 2 INDOOR UNIT HEAT EXCHANGER 2 4 5 7 6 1 10 8 11 12 3 CATCH SCREW CAP E02 817 620 E02 819 620 E02 179 667 E02 138 666 E02 151 667 E02 527 667 INDOOR HEAT EXCHANGER INDOOR HEAT EXCHANGER UNION GAS UNION GAS UNION LIQUID UNION LIQUID 12 7 1...

Page 30: ...R INDOOR COIL THERMISTOR VANE MOTOR SUPPORT SET RIGHT VANE MOTOR SUPPORT SET LEFT Symbol in Wiring Diagram Q ty unit 3 15A RIGHT LEFT UP DOWN Remarks Part No No Part Name F11 NR11 MF MF MV2 MV1 RT11 TB TB RT12 RT12 RT13 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 MS A18 WV WH E1 MS A24 WV WH E1 MS A30 WV WH E1 ...

Page 31: ...ife of AIR CLEANING FILTER is 4 months However when it becomes dirty replace it as soon as possible Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet DO NOT reuse AIR CLEANING FILTER even if it is washed DO NOT remove or attach AIR CLEANING FILTER during unit operation Model Part No MAC 1700FT MS A18WV E1 MS A24WV E1 MS A30WV E1 ...

Page 32: ...Specifications subject to change without notice C C Copyright 2003 MITSUBISHI ELECTRIC ENGINEERING CO LTD Distributed in Dec 2003 No OB325 6 Made in Japan HEAD OFFICE MITSUBISHI DENKI BLDG 2 2 3 MARUNOUCHI CHIYODA KU TOKYO100 8310 JAPAN ...

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