Mitsubishi Electric MUH-GA20VB Service Manual Download Page 1 | Manualshive

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SERVICE MANUAL

CONTENTS

1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················6
3. SPECIFICATION·················································6
4. NOISE CRITERIA CURVES ·······························7
5. OUTLINES AND DIMENSIONS ·························8
6. WIRING DIAGRAM ············································9
7. REFRIGERANT SYSTEM DIAGRAM ··············10
8. PERFORMANCE CURVES ······························11
9. SERVICE FUNCTIONS ····································22

10. TROUBLESHOOTING······································22
11. DISASSEMBLY INSTRUCTIONS ·····················29
12. PARTS LIST······················································32

Wireless type
Models

MUH-GA20VB -
MUH-GA25VB -
MUH-GA35VB -

E1

E1

E1

No. OB387

HFC

utilized

R410A

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

MUH-GA20VB -

MUH-GA25VB -
MUH-GA35VB -

E1

E1

E1

Indication of
model name

NOTE:
•This manual describes technical data of outdoor units.
•As for indoor units MSC-GA20/GA25/GA35VB -

, refer to the service manual OB385.

•As for indoor units MSC-CA20/CA25/CA35VB -

, refer to the service manual OB393.

E1

E1

OB387-1.qxp 05.2.21 10:03 AM Page 1

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Summary of Contents for MUH-GA20VB

Page 1: ...G 22 11 DISASSEMBLY INSTRUCTIONS 29 12 PARTS LIST 32 Wireless type Models MUH GA20VB MUH GA25VB MUH GA35VB E1 E1 E1 No OB387 HFC utilized R410A SPLIT TYPE HEAT PUMP AIR CONDITIONERS MUH GA20VB MUH GA25VB MUH GA35VB E1 E1 E1 Indication of model name NOTE This manual describes technical data of outdoor units As for indoor units MSC GA20 GA25 GA35VB refer to the service manual OB385 As for indoor uni...

Page 2: ...anged 780Wo540Ho255D 800Wo550Ho285D 3 Stop valve cover has been added 4 Outdoor fan motor has been changed RA6V33 FB RA6V33 KB 5 Outdoor fan motor capacitor has been changed 6 Compressor capacitor has been changed 7 Outdoor heat exchanger has been changed 2 Row 1 Row MUH A12YV MUH GA35VB 1 Indication of capacity has been changed BTU base kw 2 Dimension of outdoor unit has been changed 780Wo540Ho25...

Page 3: ... of R22 some special tools and piping parts materials are required Refer to the table below 2 Take sufficient care not to allow water and other contaminations to enter the R410A refrigerant during storage and installation since it is more susceptible to contaminations than R22 3 For refrigerant piping use clean pressure proof parts materials specifically designed for R410A Refer to 2 Refrigerant p...

Page 4: ...efrigerant from being charged into the unit Hose material and cap size have been changed to improve the pressure resistance Dedicated for HFC refrigerant 6 35 mm and 9 52 mm Description Clamp bar hole has been enlarged to reinforce the spring strength in the tool Provided for flaring work to be used with R22 flare tool Provided to prevent the back flow of oil This adapter enables you to use vacuum...

Page 5: ...urging for the purpose of environmental protection 5 Additional charge For additional charging charge the refrigerant from liquid phase of the gas cylinder If the refrigerant is charged from the gas phase composition change may occur in the refrigerant inside the cylinder and the outdoor unit In this case ability of the refrigeration cycle decreases or normal operation can be impossible However ch...

Page 6: ...1 0 25 RN092VHSHT 600 C R 3 87 C S 6 14 RA6V21 AD WHT BLK 366 BLK RED 274 800o550o285 32 47 745 1 0 65 350 NEO22 33 18 Cooling 2 3 0 9 3 00 680 99 2 76 3 22 Heating 2 5 2 86 655 100 2 62 3 62 MUH GA25VB E1 Single phase 230V 50Hz 1902 10 22 0 33 RN104VHSHT 700 C R 3 40 C S 4 56 RA6V33 KB WHT BLK 215 BLK RED 307 800o550o285 32 49 855 1 0 80 350 NEO22 33 18 Cooling 2 65 1 1 3 43 785 100 3 10 3 23 Hea...

Page 7: ...s Cooling DB35 WB24 Heating DB 7 WB 6 MUH GA25VB E1 MUH GA35VB E1 COOLING FUNCTION 49 HEATING SPL dB A LINE OUTDOORUNIT MICROPHONE 1m 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 dB re 0 0002 MICRO BAR BAND CENTER FREQUENCIES Hz Test conditions Cooling DB35 WB...

Page 8: ...iquid refrigerant pipe joint Refrigerant pipe flared 6 35 Gas refrigerant pipe joint Refrigerant pipe flared 9 52 4 3 3 5 2 holes 10X21 MUH GA25 GA35VB REQUIRED SPACE Basically open 100mm or more without any obstruction in front and on both sides of the unit 350mm or more 200mm or more 100mm or more 100mm or more Open two sides of left right or rear side Drain hole 42 Unit mm OUTDOOR UNIT MUH GA20...

Page 9: ...UTDOOR FAN MOTOR INNER FUSE TAB20 PE N 3 TB2 N L TB1 BRN 3 2 1 CN711 CN730 BLU NR61 RT61 21S4 CN661 C65 1 2 3 SR61 SR62 CN721 T61 WHT C MC S R RED BLK C1 F61 BRN DSAR CIRCUIT BREAKER BLU POWER SUPPLY N 230V 50Hz 12V TO INDOOR UNIT CONNECTING RED BLK GRN YLW 3 52C 4 BLK WHT RED MF OUTDOOR UNIT NOTE 1 About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicin...

Page 10: ...H GA25VB 3 0x 1 4x500 MUH GA35VB Capillary tube 3 0x 1 4x500 MUH GA20VB 3 0x 1 4x600 MUH GA25VB 3 0x 1 4x300 MUH GA35VB Check valve Strainer 100 Refrigerant pipe 6 35 with heat insulator Refrigerant flow in cooling Refrigerant flow in heating Unit mm Stop valve with service port R V coil heating ON cooling OFF Flared connection Flared connection Compressor Stop valve MUH GA20VB MUH GA25VB MUH GA35...

Page 11: ...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 pro vided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve 1 GUARANTEED VOLTAGE 198 264V 2 AIR FLOW Air flow should be set at MAX 3 MAIN READINGS ...

Page 12: ...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 ...

Page 13: ...E1 Outdoor low pressure Ambient temperature C Ambient humidity Ambient temperature C Ambient humidity Outdoor unit current A 18 32 230V 15 20 50 25 60 30 70 35 0 7 0 8 0 9 1 0 1 1 1 2 1 3 7 8 9 10 11 12 13 MUH GA25VB E1 Outdoor low pressure Ambient temperature C Ambient humidity 15 20 50 25 60 30 70 35 1 2 4 3 18 32 230V MUH GA25VB E1 Ambient temperature C Ambient humidity Outdoor unit current A k...

Page 14: ...re 7 15 20 C Wet bulb temperature 6 12 14 5 C 7 21 230V 5 10 15 20 25 3 4 5 6 7 21 230V 5 10 15 20 25 2 3 4 5 7 21 230V 5 10 15 20 25 2 3 4 5 Outdoor unit current A Outdoor unit current A Outdoor unit current A Ambient temperature C Ambient temperature C Ambient temperature C MUH GA20VB E1 MUH GA25VB E1 MUH GA35VB E1 ...

Page 15: ... 32 744 2 94 0 94 0 32 765 28 18 2 70 2 27 0 84 572 2 59 2 17 0 84 601 2 48 2 09 0 84 629 2 39 2 01 0 84 658 28 20 2 82 2 03 0 72 601 2 70 1 95 0 72 636 2 62 1 89 0 72 651 2 53 1 82 0 72 679 28 22 2 93 1 76 0 60 622 2 83 1 70 0 60 661 2 76 1 66 0 60 679 2 65 1 59 0 60 708 28 24 3 08 1 48 0 48 651 2 97 1 42 0 48 686 2 90 1 39 0 48 708 2 81 1 35 0 48 744 28 26 3 17 1 14 0 36 686 3 08 1 11 0 36 722 3...

Page 16: ... 32 851 2 54 0 81 0 32 869 28 18 2 25 1 89 0 84 701 2 07 1 74 0 84 744 1 99 1 67 0 84 758 28 20 2 37 1 71 0 72 729 2 21 1 59 0 72 765 2 13 1 53 0 72 787 28 22 2 51 1 50 0 60 758 2 35 1 41 0 60 801 2 27 1 36 0 60 815 28 24 2 65 1 27 0 48 787 2 48 1 19 0 48 822 2 42 1 16 0 48 840 28 26 2 78 1 00 0 36 815 2 62 0 94 0 36 851 2 54 0 91 0 36 869 29 18 2 25 1 98 0 88 701 2 07 1 82 0 88 744 1 99 1 75 0 88...

Page 17: ... 28 853 3 39 0 95 0 28 877 28 18 3 11 2 49 0 80 656 2 98 2 39 0 80 689 2 86 2 29 0 80 722 2 76 2 20 0 80 754 28 20 3 25 2 21 0 68 689 3 11 2 12 0 68 730 3 02 2 05 0 68 746 2 92 1 98 0 68 779 28 22 3 38 1 89 0 56 713 3 26 1 83 0 56 759 3 18 1 78 0 56 779 3 05 1 71 0 56 812 28 24 3 55 1 56 0 44 746 3 42 1 50 0 44 787 3 34 1 47 0 44 812 3 23 1 42 0 44 853 28 26 3 66 1 17 0 32 787 3 55 1 14 0 32 828 3...

Page 18: ... 28 976 2 93 0 82 0 28 996 28 18 2 60 2 08 0 80 804 2 39 1 91 0 80 853 2 29 1 83 0 80 869 28 20 2 73 1 86 0 68 836 2 54 1 73 0 68 877 2 45 1 67 0 68 902 28 22 2 89 1 62 0 56 869 2 70 1 51 0 56 918 2 61 1 46 0 56 935 28 24 3 05 1 34 0 44 902 2 86 1 26 0 44 943 2 78 1 22 0 44 964 28 26 3 21 1 03 0 32 935 3 02 0 97 0 32 976 2 93 0 94 0 32 996 29 18 2 60 2 18 0 84 804 2 39 2 00 0 84 853 2 29 1 93 0 84...

Page 19: ...34 4 48 1 08 0 24 1166 28 18 4 11 3 13 0 76 872 3 94 2 99 0 76 916 3 78 2 87 0 76 959 3 64 2 77 0 76 1003 28 20 4 29 2 74 0 64 916 4 11 2 63 0 64 970 3 99 2 55 0 64 992 3 85 2 46 0 64 1036 28 22 4 46 2 32 0 52 948 4 31 2 24 0 52 1008 4 20 2 18 0 52 1036 4 03 2 09 0 52 1079 28 24 4 69 1 88 0 40 992 4 52 1 81 0 40 1046 4 41 1 76 0 40 1079 4 27 1 71 0 40 1134 28 26 4 83 1 35 0 28 1046 4 69 1 31 0 28 ...

Page 20: ...24 1297 3 87 0 93 0 24 1324 28 18 3 43 2 61 0 76 1068 3 15 2 39 0 76 1134 3 03 2 30 0 76 1155 28 20 3 61 2 31 0 64 1112 3 36 2 15 0 64 1166 3 24 2 07 0 64 1199 28 22 3 82 1 98 0 52 1155 3 57 1 86 0 52 1221 3 45 1 79 0 52 1243 28 24 4 03 1 61 0 40 1199 3 78 1 51 0 40 1254 3 68 1 47 0 40 1281 28 26 4 24 1 19 0 28 1243 3 99 1 12 0 28 1297 3 87 1 08 0 28 1324 29 18 3 43 2 74 0 80 1068 3 15 2 52 0 80 1...

Page 21: ...INPUT Q INPUT CAPACITY 3 0 kW INPUT 820 W 15 21 26 1 89 1 80 1 62 533 574 615 2 28 2 16 2 01 640 681 722 2 67 2 55 2 37 722 754 795 3 06 2 91 2 76 779 812 853 3 45 3 30 3 15 828 853 894 3 81 3 66 3 51 853 877 918 4 20 4 04 3 90 869 910 943 MSC GA35VB MUH GA35VB E1 E1 OUTDOOR WB INDOOR 10 5 0 5 10 15 20 DB Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT CAPACITY 3 7 kW INPUT 1020 W 15 21 26...

Page 22: ...plug 2 Be sure to turn OFF the power supply 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 MUH GA20VB MUH GA25VB MUH ...

Page 23: ...Cause Outdoor unit Trouble of thermistor in outdoor unit 7 time flash Cause Outdoor unit Trouble of outdoor control system Check room temperature thermistor and indoor coil thermis tor Refer to 10 5 Test point diagram and voltage Refer to Check of indoor fan motor Refer to 10 4 E Check of outdoor thermistor Replace the deicer P C board Refer to 10 4 D How to check mis wiring and serial signal erro...

Page 24: ...outdoor terminal block TB1 No No Is the switch SW2 2 on the indoor electronic control P C board set to MUH type No Change the switch SW 2 2 on the indoor electronic control P C board to MUH type Yes Is there 5V DC between J205 J101 on the deicer P C board Is there 5V DC between J205 J101 on the deicer P C board Compressor MC INNER PROTECTOR MUH GA20 GA25VB 150i 5 C OPEN 90i10 C CLOSE MUH GA35VB 15...

Page 25: ...is not short circuit After 3 minutes does the unit operate in HEAT mode Ok No Is there 230V AC between CN7211 2 on the deicer P C board Replace the deicer P C board Yes Yes Yes No Replace the R V coil Turn ON the power supply and operate the indoor unit in COOL mode by pressing the EMERGENCY OPERATION switch Unit operates HEAT mode even if it is set to COOL mode w First measure the resistance of R...

Page 26: ... contact or disconnection of wire Make them sure Replace the indoor electronic control P C board Turn ON the power supply outdoor unit Is there 230V AC between outdoor terminal block L N TB1 No Check the outdoor power supply power supply cord and connection Yes Turn ON the power supply indoor unit No Replace the deicer P C board Yes No Make the wiring between CN730 on the deicer P C board and outd...

Page 27: ...n ON the power supply and press the EMERGENCY OPERATION switch Is the resistance of thermistor normal No Yes Does the unit operate 10 minutes or more Replace the deicer P C board OK Defective contact of the connector is considered Turn OFF the power supply Start When OPERATION INDICATOR lamp flashes 6 time Thermistors in the outdoor unit are abnormal ...

Page 28: ... R V coil 230V AC F61 Fuse 2A 250V CN661 1 2 Defrost thermistor RT61 12V DC J204 J101 R601 5 10VDC 5V DC J205 J101 Power supply input 230V AC NR61 Varistor Jumper wire for change in defrost setting JRF JRG Refer to 9 2 Defrost interval time short pin JPDS JPSG Refer to 9 1 10 5 Test point diagram and voltage ...

Page 29: ...cking mechanism 1Slide the sleeve 2Pull the terminal while pushing the locking lever 1Hold the sleeve and pull out the terminal slowly The terminal which has the locking mechanism can be detached as shown below There are two types Refer to 1 and 2 of the terminal with locking mechanism The terminal without locking mechanism can be detached by pulling it out Check the shape of the terminal before d...

Page 30: ...peller 4 Disconnect the outdoor fan motor connector 5 Remove screws fixing the fan motor 6 Remove the outdoor fan motor Photo 5 Propeller Propeller nut Screw of the outdoor fan motor Terminal cover Screws of the relay panel OPERATING PROCEDURE PHOTOS 2 Removing the deicer P C board 1 Remove the service panel and the cabinet 2 Disconnect all the connectors and the terminals on the deicer P C board ...

Page 31: ...from the glass terminal of the com pressor 6 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes until the pressure gauge shows 0 kg cm2 0 MPa 7 Disconnect the welded part of the discharge pipe 8 Disconnect the welded part of the suction pipe 9 Remove nuts fixing the compressor 10 Remove the compressor Photo 6 Compressor Suction pipe 4 Way valve Discharge pipe Compressor nuts ...

Page 32: ...32 PARTS LIST 12 22 3 5 2 21 1 W 15 12 1 OUTDOOR UNIT STRUCTURAL PARTS MUH GA20VB MUH GA25VB MUH GA35VB E1 E1 E1 4 17 14 19 20 18 13 6 7 8 9 10 11 12 16 23 W This figure shows MUH GA20VB 24 ...

Page 33: ...ET COMPRESSOR COMPRESSOR COMPRESSOR STOP VALVE GAS STOP VALVE LIQUID BACK PANEL BACK PANEL SERVICE PANEL DRAIN SOCKET TERMINAL BLOCK TERMINAL BLOCK 4 WAY VALVE 4 WAY VALVE COMPRESSOR CAPACITOR COMPRESSOR CAPACITOR COMPRESSOR CAPACITOR SURGE ABSORBER DEICER P C BOARD DEICER P C BOARD DEFROST THERMISTOR CONDENSER NET CONDENSER NET TOP PANEL SEPARATOR MOTOR SUPPORT R V COIL R V COIL FUSE VARISTOR CHE...

Page 34: ...34 ...

Page 35: ...35 ...

Page 36: ...RIC ENGINEERING CO LTD Distributed in Feb 2005 No OB387 6 Made in Japan New publication effective Feb 2005 Specifications subject to change without notice HEAD OFFICE MITSUBISHI DENKI BLDG 2 2 3 MARUNOUCHI CHIYODA KU TOKYO100 8310 JAPAN ...

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