Mitsubishi Electric MUZ-EF25VG Service Manual Download Page 51

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OPERATING PROCEDURE

PHOTOS/FIGURES

2. Removing the inverter assembly, inverter P.C. board

(1) Remove the cabinet and panels. (Refer to section 1.)
(2) Disconnect the lead wire to the reactor and the following con-

nectors:

CN721 (R.V. coil)
CN931, CN932 (Fan motor)
CN641 (Defrost thermistor and discharge temperature ther-

mistor)

CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
CN724 (LEV)

(3) Remove the compressor connector (CN61).
(4) Remove the screws fixing the heat sink support and the sep-

arator.

(5) Remove the fixing screws of the terminal block support and

the back panel.

(6) Remove the inverter assembly.
(7) Remove the screw of the earth wire and screw of the termi-

nal block support.

(8) Remove the heat sink support from the P.C. board support.
(9) Remove the screw of the inverter P.C. board and remove the

inverter P.C. board from the P.C. board support.

Photo 4

Photo 5 (Inverter assembly)

Photo 6

3. Removing R.V. coil

(1) Remove the cabinet and panels. (Refer to section 1.)
(2) Disconnect the following connectors:

CN721 (R.V. coil)

(3) Remove the R.V. coil.

4. Removing the discharge temperature thermistor,

defrost thermistor, outdoor heat exchanger tempera-
ture thermistor and ambient temperature thermistor

(1) Remove the cabinet and panels. (Refer to section 1.)
(2) Disconnect the lead wire to the reactor and the following con-

nectors:
<Inverter P.C. board>

CN641 (Defrost thermistor and discharge temperature ther-

mistor)

CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)

(3) Pull out the discharge temperature thermistor from its holder.
(4) Pull out the defrost thermistor from its holder. (Photo 7)
(5) Pull out the outdoor heat exchanger temperature thermistor

from its holder. (Photo 7)

(6) Pull out the ambient temperature thermistor from its holder.

Discharge temperature thermistor

Screw of the

R.V. coil

Screws of the heat sink
support and the separator

Screws of the terminal block
support and the back panel

Heat sink

Screw of the
earth wire

Screw of the
Terminal block
support

Screw of the
inverter P.C. board

Heat sink support

P.C. board
support

Terminal
block
support

OBH832

Summary of Contents for MUZ-EF25VG

Page 1: ...3 PART NAMES AND FUNCTIONS 5 4 SPECIFICATION 6 5 NOISE CRITERIA CURVES 8 6 OUTLINES AND DIMENSIONS 9 7 WIRING DIAGRAM 10 8 REFRIGERANT SYSTEM DIAGRAM 12 9 PERFORMANCE CURVES 14 10 ACTUATOR CONTROL 28 11 SERVICE FUNCTIONS 29 12 TROUBLESHOOTING 30 13 DISASSEMBLY INSTRUCTIONS 50 Models MUZ EF25VG E1 ET1 MUZ EF25VGH E1 MUZ EF35VG E1 ET1 MUZ EF35VGH E1 MUZ EF42VG E1 ET1 MUZ EF50VG E1 ET1 MUZ EF25VG MUZ...

Page 2: ... pour water into the electric parts Do not touch the refrigerant Do not touch the hot or cold areas in the refrigeration cycle When the repair or the inspection of the circuit needs to be done without turning off the power exercise great caution not to touch the live parts Use the specified refrigerant only Never use any refrigerant other than that specified Doing so may cause a burst an explosion...

Page 3: ...ng changed they shall be fit for the purpose and to the correct specification At all times the manufacturer s maintenance and service guidelines shall be followed If in doubt consult the manufacturer s technical department for assistance The following checks shall be applied to installations using flammable refrigerants The charge size is in accordance with the room size within which the refrigera...

Page 4: ...ely familiar with the equipment and all its detail It is recommended good practice that all refrigerants are recovered safely Prior to the task being carried out an oil and refrigerant sample shall be taken in case analysis is required prior to re use of reclaimed refrigerant It is essential that electrical power is available before the task is commenced a Become familiar with the equipment and it...

Page 5: ...ck and side MUZ EF25VG MUZ EF35VG MUZ EF42VG MUZ EF25VGH MUZ EF35VGH PART NAMES AND FUNCTIONS 3 ACCESSORIES MODELS MUZ EF25VG MUZ EF35VG MUZ EF42VG MUZ EF50VG Drain socket 1 MUZ EF50VG Air outlet Drain outlet Piping Drain hose Air inlet back and side OBH832 ...

Page 6: ... 5 96 6 41 Refrigeration oil Model L 0 27 FW68S 0 35 FW68S Fan motor Model RC0J50 NC RC0J50 RA Current 1 Cooling A 0 18 0 25 0 22 0 30 Heating 0 20 0 23 0 23 0 30 Dimensions W H D mm 800 550 285 800 714 285 Weight kg 31 34 35 40 Special remarks Dehumidification Cooling L h 0 1 1 0 1 6 2 2 Air flow 1 Cooling High m3 h 2 178 2 058 2 058 2 412 Low 1 038 936 906 1 320 Heating High 2 076 1 962 1 962 2 ...

Page 7: ...00 V Fuse F61 25A 250V F62 15A 250V F701 F801 F901 T3 15AL250V Defrost heater H 230 V 60W 230 V 60W Power module IC700 15 A 600 V 20 A 600 V IC932 5 A 600 V Expansion valve coil LEV 12 V DC Reactor L61 18 mH 23 mH Switch power transistor Q821 30 37 A 600 V Current limiting PTC thermistor PTC64 PTC65 33 Ω Terminal block TB1 5 P Relay X63 3 A 250 V X64 20 A 250 V X66 3 A 250 V 3 A 250 V X69 10 A 230...

Page 8: ...EATING 49 50 NC 10 MUZ EF35VG MUZ EF35VGH 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 OCTAVE BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR BAND CENTER FREQUENCIES Hz COOLING FUNCTION SPL dB A LINE HEATING 50 NC 10 51 MUZ EF42VG 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 OCTAVE BAND SOUND...

Page 9: ...9 MUZ EF50VG OUTLINES AND DIMENSIONS 6 Unit mm MUZ EF25VG MUZ EF35VG MUZ EF42VG MUZ EF25VGH MUZ EF35VGH MUZ EF25 35 42VG MUZ EF25 35VGH MUZ EF50VG OBH832 ...

Page 10: ...10 WIRING DIAGRAM 7 MUZ EF25VG E1 ET1 MUZ EF35VG E1 ET1 MUZ EF25VGH E1 MUZ EF35VGH E1 OBH832 ...

Page 11: ...11 MUZ EF42VG E1 ET1 MUZ EF50VG E1 ET1 OBH832 ...

Page 12: ...re thermistor RT68 Stop valve with service port Muffler REFRIGERANT SYSTEM DIAGRAM 8 Unit mm MUZ EF42VG Outdoor heat exchanger Flared connection Defrost thermistor RT61 Discharge temperature thermistor RT62 Flared connection Stop valve with strainar Refrigerant flow in cooling Compressor 4 way valve Refrigerant flow in heating Refrigerant pipe ø9 52 with heat insulator Refrigerant pipe ø6 35 with ...

Page 13: ...100 Muffler Capillary tube ø3 0 ø2 0 210 2 Max Length A Max Height difference B Indoor unit Outdoor unit MAX REFRIGERANT PIPING LENGTH and MAX HEIGHT DIFFERENCE Model Refrigerant piping m Piping size O D mm Max Length A Max Height difference B Gas Liquid MUZ EF25 35VG H MUZ EF42VG 20 12 9 52 6 35 MUZ EF50VG 30 15 ADDITIONAL REFRIGERANT CHARGE R32 g Model Outdoor unit precharged Refrigerant piping ...

Page 14: ...wn 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 EMERGE...

Page 15: ...5 8 14 3 12 7 11 1 9 5 7 9 6 3 MUZ EF50VG MUZ EF42VG MUZ EF35VG MUZ EF25VG MUZ EF25VGH MUZ EF35VGH Outdoor intake air Wet bulb temperature C 20 15 10 5 0 5 10 15 0 4 0 5 0 6 0 7 0 8 0 9 1 0 1 1 1 2 1 3 Heating capacity at Rated frequency Capacity correction factor 15 20 26 Indoor intake air Dry bulb temperature Indoor air Dry bulb temperature difference C 17 6 16 2 14 9 13 5 12 2 10 8 9 5 8 1 6 8 ...

Page 16: ... input Capacity correction factors The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz The operational frequency of compressor Hz Correction of Cooling...

Page 17: ...ion TEST RUN OPERATION Refer to 9 3 9 4 OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT Dry bulb temperature C Relative humidity 20 50 25 60 30 70 9 3 HOW TO OPERATE FIXED FREQUENCY OPERATION Test run operation 1 Press EMERGENCY OPERATION switch to start COOL or HEAT mode COOL Press once HEAT Press twice 2 Test run operation starts and continues to operate for 30 minutes 3 Compressor operates at rat...

Page 18: ...H MUZ EF25VG MUZ EF25VGH Outdoor unit current MUZ EF42VG MUZ EF50VG 0 5 10 15 20 25 1 2 3 4 0 5 10 15 20 25 3 4 5 6 0 5 10 15 20 25 1 2 3 4 0 5 10 15 20 25 3 4 5 6 7 Ambient temperature C Outdoor current A Ambient temperature C Outdoor current A Ambient temperature C Outdoor current A Ambient temperature C Outdoor current A MUZ EF35VG MUZ EF35VGH MUZ EF25VG MUZ EF25VGH Outdoor unit current MUZ EF4...

Page 19: ...7 0 79 535 27 24 3 35 2 24 0 67 491 3 23 2 16 0 67 518 3 15 2 11 0 67 535 3 05 2 04 0 67 562 27 26 3 45 1 90 0 55 518 3 35 1 84 0 55 545 3 30 1 82 0 55 562 3 20 1 76 0 55 578 28 18 2 94 2 94 1 00 432 2 81 2 81 1 00 454 2 70 2 70 1 00 475 2 60 2 60 1 00 497 28 20 3 06 2 91 0 95 454 2 94 2 79 0 95 481 2 85 2 71 0 95 491 2 75 2 61 0 95 513 28 22 3 19 2 65 0 83 470 3 08 2 55 0 83 500 3 00 2 49 0 83 51...

Page 20: ...1 0 79 605 2 38 1 88 0 79 626 27 24 2 88 1 93 0 67 594 2 70 1 81 0 67 621 2 55 1 71 0 67 648 27 26 3 03 1 66 0 55 616 2 85 1 57 0 55 643 2 68 1 47 0 55 670 28 18 2 45 2 45 1 00 529 2 25 2 25 1 00 562 2 08 2 08 1 00 583 28 20 2 58 2 45 0 95 551 2 40 2 28 0 95 578 2 23 2 11 0 95 610 28 22 2 73 2 26 0 83 572 2 55 2 12 0 83 605 2 38 1 97 0 83 626 28 24 2 88 2 04 0 71 594 2 70 1 92 0 71 621 2 55 1 81 0...

Page 21: ...0 0 62 901 27 24 4 69 2 35 0 50 828 4 52 2 26 0 50 874 4 41 2 21 0 50 901 4 27 2 14 0 50 946 27 26 4 83 1 84 0 38 874 4 69 1 78 0 38 919 4 62 1 76 0 38 946 4 48 1 70 0 38 974 28 18 4 11 3 70 0 90 728 3 94 3 54 0 90 764 3 78 3 40 0 90 801 3 64 3 28 0 90 837 28 20 4 29 3 34 0 78 764 4 11 3 21 0 78 810 3 99 3 11 0 78 828 3 85 3 00 0 78 865 28 22 4 46 2 95 0 66 792 4 31 2 84 0 66 842 4 20 2 77 0 66 86...

Page 22: ...3 33 2 06 0 62 1056 27 24 4 03 2 01 0 50 1001 3 78 1 89 0 50 1047 3 57 1 79 0 50 1092 27 26 4 24 1 61 0 38 1037 3 99 1 52 0 38 1083 3 75 1 42 0 38 1128 28 18 3 43 3 09 0 90 892 3 15 2 84 0 90 946 2 91 2 61 0 90 983 28 20 3 61 2 81 0 78 928 3 36 2 62 0 78 974 3 12 2 43 0 78 1028 28 22 3 82 2 52 0 66 965 3 57 2 36 0 66 1019 3 33 2 19 0 66 1056 28 24 4 03 2 17 0 54 1001 3 78 2 04 0 54 1047 3 57 1 93 ...

Page 23: ...7 24 5 63 2 48 0 44 1092 5 42 2 38 0 44 1152 5 29 2 33 0 44 1188 5 12 2 25 0 44 1248 27 26 5 80 1 85 0 32 1152 5 63 1 80 0 32 1212 5 54 1 77 0 32 1248 5 38 1 72 0 32 1284 28 18 4 94 4 15 0 84 960 4 73 3 97 0 84 1008 4 54 3 81 0 84 1056 4 37 3 67 0 84 1104 28 20 5 15 3 70 0 72 1008 4 94 3 55 0 72 1068 4 79 3 45 0 72 1092 4 62 3 33 0 72 1140 28 22 5 36 3 21 0 60 1044 5 17 3 10 0 60 1110 5 04 3 02 0 ...

Page 24: ...3 99 2 23 0 56 1392 27 24 4 83 2 13 0 44 1320 4 54 2 00 0 44 1380 4 28 1 88 0 44 1440 27 26 5 08 1 63 0 32 1368 4 79 1 53 0 32 1428 4 49 1 44 0 32 1488 28 18 4 12 3 46 0 84 1176 3 78 3 18 0 84 1248 3 49 2 93 0 84 1296 28 20 4 33 3 11 0 72 1224 4 03 2 90 0 72 1284 3 74 2 69 0 72 1356 28 22 4 58 2 75 0 60 1272 4 28 2 57 0 60 1344 3 99 2 39 0 60 1392 28 24 4 83 2 32 0 48 1320 4 54 2 18 0 48 1380 4 28...

Page 25: ...7 24 6 70 2 68 0 40 1401 6 45 2 58 0 40 1478 6 30 2 52 0 40 1525 6 10 2 44 0 40 1602 27 26 6 90 1 93 0 28 1478 6 70 1 88 0 28 1555 6 60 1 85 0 28 1602 6 40 1 79 0 28 1648 28 18 5 88 4 70 0 80 1232 5 63 4 50 0 80 1294 5 40 4 32 0 80 1355 5 20 4 16 0 80 1417 28 20 6 13 4 17 0 68 1294 5 88 4 00 0 68 1371 5 70 3 88 0 68 1401 5 50 3 74 0 68 1463 28 22 6 38 3 57 0 56 1340 6 15 3 44 0 56 1425 6 00 3 36 0...

Page 26: ...4 75 2 47 0 52 1786 27 24 5 75 2 30 0 40 1694 5 40 2 16 0 40 1771 5 10 2 04 0 40 1848 27 26 6 05 1 69 0 28 1756 5 70 1 60 0 28 1833 5 35 1 50 0 28 1910 28 18 4 90 3 92 0 80 1509 4 50 3 60 0 80 1602 4 15 3 32 0 80 1663 28 20 5 15 3 50 0 68 1571 4 80 3 26 0 68 1648 4 45 3 03 0 68 1740 28 22 5 45 3 05 0 56 1632 5 10 2 86 0 56 1725 4 75 2 66 0 56 1786 28 24 5 75 2 53 0 44 1694 5 40 2 38 0 44 1771 5 10...

Page 27: ...26 2 16 713 2 68 836 3 16 922 3 68 988 4 20 1036 4 68 1064 5 20 1093 MUZ EF42VG CAPACITY 5 4 kW INPUT 1455 W INDOOR DB C OUTDOOR WB C 10 5 0 5 10 15 20 Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT 15 3 40 946 4 10 1135 4 81 1280 5 51 1382 6 21 1470 6 86 1513 7 56 1542 21 3 24 1019 3 89 1208 4 59 1339 5 24 1440 5 94 1513 6 59 1557 7 26 1615 26 2 92 1091 3 62 1280 4 27 1411 4 97 1513 5 67...

Page 28: ...essor has stopped running 10 3 RELATION BETWEEN MAIN SENSOR AND ACTUATOR Sensor Purpose Actuator Compressor LEV Outdoor fan motor R V coil Indoor fan motor Defrost heater Discharge temperature thermistor Protection Indoor coil temperature thermistor Cooling Coil frost prevention Heating High pressure protec tion Defrost thermistor Heating Defrosting Fin temperature thermistor Protection Ambient te...

Page 29: ...ressor at low outside temperature The pre heat control prevents this interference The pre heat control turns ON when the discharge temperature thermis tor is 20 C or below When the pre heat control turns ON the compressor is energized About 50 W Pre heat control setting JK ON To activate the pre heat control cut the JK wire of the inverter P C board OFF To deactivate the pre heat control solder th...

Page 30: ...When removing the electronic control P C board hold the edge of the board with care NOT to apply stress on the components 5 When connecting or disconnecting the connectors hold the connector housing DO NOT pull the lead wires TROUBLESHOOTING 12 3 Troubleshooting procedure 1 Check if the OPERATION INDICATOR lamp on the indoor unit is blinking on and off to indicate an abnormality To make sure check...

Page 31: ...es the upper lamp on the indoor unit stay ON for 3 seconds When it stays ON for 3 seconds without beep The outdoor unit is abnormal The indoor unit is abnormal Check the blinking pattern and identify the abnormal point by referring to the table of indoor unit failure mode recall function Refer to indoor unit service manual Make sure to check at least 2 consecutive blinking cycles 2 Releasing the f...

Page 32: ...ure mode recall function Release the failure mode recall function by the following procedures Turn OFF the power supply and turn it ON again Press RESET button of the remote controller Repair the failure parts The outdoor unit is normal Release the failure mode recall function accord ing to the left mentioned procedure Deleting the memorized abnormal condition After repairing the unit recall the f...

Page 33: ...s into power module IC700 Reconnect compressor connector Refer to 12 5 How to check inverter compressor Check stop valve Compressor synchronous abnormality Compressor start up failure protection 12 time blink 2 5 seconds OFF Waveform of compressor current is distorted Reconnect compressor connector Refer to 12 5 How to check inverter compressor 5 time blink 2 5 seconds OFF Discharge temperature Te...

Page 34: ...verter compressor Each phase current of compressor 9 time blink 2 5 seconds OFF Each phase current of compressor cannot be detected normally 14 time blink or more 2 5 seconds OFF Stop valve Closed valve 14 time blink 2 5 seconds OFF Closed valve is detected by compressor current Check stop valve 4 way valve Pipe temperature 16 time blink 2 5 seconds OFF The 4 way valve does not work properly The i...

Page 35: ... amount Refer to 12 5 Check of LEV 11 4 time blink 2 5 seconds OFF Fin temperature P C board tem perature thermistor overheat protection Temperature of fin temperature thermistor on the heat sink exceeds 75 86 C or temperature of P C board temperature thermistor on the inverter P C board exceeds 72 85 C Check around outdoor unit Check outdoor unit air passage Refer to 12 5 Check of outdoor fan mot...

Page 36: ...unction PAM pro tection will be activated in the fol lowing cases 1 Instantaneous power voltage drop Short time power failure 2 When the power supply voltage is high 23 9 time blink 2 5 seconds OFF Inverter check mode The connector of compressor is disconnected inverter check mode starts Check if the connector of the com pressor is correctly connected Refer to 12 5 How to check inverter compressor...

Page 37: ...board for the chart of thermistor Compressor Measure the resistance between terminals using a tester Temperature 10 40 C Normal Ω MUZ EF25 35VG H MUZ EF42 50VG U V U W V W 1 59 2 16 0 82 1 11 W U V WHT RED BLK Outdoor fan motor Measure the resistance between lead wires using a tester Temperature 10 40 C Color of lead wire Normal Ω MUZ EF25 35 42VG MUZ EF25 35VGH MUZ EF50VG RED BLK BLK WHT WHT RED ...

Page 38: ...50 130 V The voltage may differ according to the tester Operation method Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the indoor unit TEST RUN OPERA TION Refer to 9 3 Measurement point At 3 points BLK U WHT V BLK U RED W WHT V RED W NOTE 1 Output voltage varies according to power supply voltage 2 Measure the voltage by analog type tester 3 During this check LED of t...

Page 39: ... TEST RUN OPERATION Refer to 9 3 Measurement Measure the time from the start of compressor to the stop of compressor due to overcurrent Compressor starts Abnormal IC700 failure Compressor winding short Abnormal Compressor lock out Starting defect Abnormal Poor contact Inverter P C board defect Disconnected connector Abnormal Refrigerant circuit defect Closed valve Normal 0 second 1 second 2 second...

Page 40: ... minutes or more without showing thermistor abnormality OK Cause is poor contact Yes Yes Disconnect the connector of thermistor in the inverter P C board see below table and measure the resistance of thermistor Thermistor Symbol Connector Pin No Board Defrost RT61 Between CN641 pin1 and pin2 Inverter P C board Discharge temperature RT62 Between CN641 pin3 and pin4 Fin temperature RT64 Between CN64...

Page 41: ...lace the inverter P C board Replace the 4 way valve Unit operates COOL mode even if it is set to HEAT mode Is there 230 V AC between CN721 and on the inverter P C board 3 minutes after the power supply is turned ON Yes No Replace the inverter P C board Replace the 4 way valve Unit operates HEAT mode even if it is set to COOL mode Disconnect connector between the compressor and the IGBT module IC70...

Page 42: ...easure the voltage of CN931 Between 1 and 5 Between 2 and 5 Between 3 and 5 Does the voltage between each terminal become 5 and 0 V DC repeatedly Does the outdoor fan motor rotate smoothly Replace the outdoor fan motor Replace the inverter P C board Yes Yes No Fixed to either 5 or 0 V DC No No Yes Disconnect the connectors CN931 and CN932 from the inverter P C board Check the connection between th...

Page 43: ...amp on the indoor unit light up Does LED on the inverter P C board light up or blink Refer to 12 6 1 No Replace the inverter P C board Is there bus bar voltage 260 370 V DC between DB61 and DB61 on the inverter P C board Refer to 12 6 1 No Check the electric parts in main circuit Yes Yes No Disconnect the connector between the compressor and the power module IC700 Turn ON power supply and press EM...

Page 44: ...ge by an analog tester Properly fix the LEV coil to the expansion valve Replace the inverter P C board Replace the LEV coil Replace the expansion valve Is LEV coil properly fixed to the expansion valve Does the resistance of LEV coil have the characteristics Refer to 12 4 Do you hear the expansion valve click click Do you feel the expansion valve vibrate when touching it Turn ON the power supply P...

Page 45: ...door fan motor If the connection is poor make it correct Operate the outdoor unit by starting EMERGENCY OPERATION Check the LED indication on the in verter P C board Does the LED blink 10 times Replace the inverter P C board Check the corresponding parts following LED indication Refer to 12 3 Yes No Yes 10 time blink No L Check of inverter P C board OBH832 ...

Page 46: ...or terminal block S2 and S3 Yes No Does the upper lamp of OPERA TION INDICATOR lamp on the indoor unit blink continuously 6 min utes after the emergency operation starts No Does the outdoor LED light up Replace the indoor elec tronic control P C board Yes Does the outdoor LED blink 6 times Yes Yes Confirm that the thermostat is OFF and wiring is not loose No Does DC 6V or more occur be tween indoo...

Page 47: ...air trapped in the refrigerant circuit Close the stop valve and disconnect the power plug or turn the breaker OFF The unit occasionally stops when the stop valve is opened or closed during operation Open the stop valve and start the cooling operation again Yes No The refrigerant gas amount may be 60 or less than the normal amount Identify where the gas is leaking from and fix the leak CAUTION Do n...

Page 48: ...he installation condition combination of specific conditions such as antennas or wiring Check the following before asking for service 1 Devices affected by the electromagnetic noise TV sets radios FM AM broadcast shortwave 2 Channel frequency broadcast station affected by the electromagnetic noise 3 Channel frequency broadcast station unaffected by the electromagnetic noise 4 Layout of indoor outd...

Page 49: ... RT65 CN643 Discharge temperature thermistor RT62 CN641 Defrost thermistor RT61 CN641 DB61 260 370 V DC Front side of unit 230 V AC Output to drive compressor LDU LDV LDW Fuse F701 T3 15AL250V R V coil 21S4 CN721 230 V AC Jumper wire for changing defrost setting JS Signal of outdoor fan motor CN931 230 V AC Outdoor heat exchanger temperature thermistor RT68 CN644 Jumper wire for pre heat control s...

Page 50: ...hanism Slide the sleeve Pull the terminal while pushing the locking lever Hold the sleeve and pull out the terminal slowly Connector Sleeve Locking lever Detaching method of the terminal with locking mechanism The terminal which has the locking mechanism can be detached as shown below There are 2 types of the terminals with locking mechanism The terminal without locking mechanism can be detached b...

Page 51: ...net and panels Refer to section 1 2 Disconnect the following connectors Inverter P C board CN721 R V coil 3 Remove the R V coil 4 Removing the discharge temperature thermistor defrost thermistor outdoor heat exchanger tempera ture thermistor and ambient temperature thermistor 1 Remove the cabinet and panels Refer to section 1 2 Disconnect the lead wire to the reactor and the following con nectors ...

Page 52: ...ove the inverter assembly Refer to section 2 3 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes until the pressure gauge shows 0 kg cm2 0 MPa 4 Detach the brazed part of the suction and the discharge pipe connected with compressor 5 Remove the nuts of compressor legs 6 Remove the compressor 7 Detach the brazed part of pipes connected with 4 way valve 7 Removing the LEV asse...

Page 53: ...ce panel 5 Remove the top panel 6 Remove the valve cover 7 Disconnect the power supply and indoor outdoor connect ing wire 8 Remove the screws of the cabinet 9 Remove the cabinet 10 Remove the screws of the back panel 11 Remove the back panel Photo 2 Photo 1 53 Screws of the cabinet Screws of the top panel Screws of the cabinet Screws of the top panel Screws of the service panel Screw of the valve...

Page 54: ...anger temperature thermistor the defrost thermistor and discharge tempera ture thermistor to the connector on the inverter P C board Pull the lead wires toward you and put them on the right hook on the P C board support 2 Connect the lead wires of the LEV to the connector on the inverter P C board Pull the lead wires toward you and put them on the right hook on the P C board support 3 Connect the ...

Page 55: ...utdoor heat exchanger temperature thermistor 3 Pull out the discharge temperature thermistor from its holder 4 Pull out the defrost thermistor from its holder 5 Pull out the outdoor heat exchanger temperature thermistor from its holder 6 Pull out the ambient temperature thermistor from its holder 5 Removing outdoor fan motor 1 Remove the cabinet and panels Refer to section 1 2 Disconnect the follo...

Page 56: ...ach the brazed part of the suction and the discharge pipe connected with compressor 5 Remove the compressor nuts 6 Remove the compressor 7 Detach the brazed part of pipes connected with 4 way valve Photo 9 56 HEAD OFFICE TOKYO BUILDING 2 7 3 MARUNOUCHI CHIYODA KU TOKYO 100 8310 JAPAN Copyright 2019 MITSUBISHI ELECTRIC CORPORATION Published Jan 2019 No OBH832 Made in Japan Specifications are subjec...

Page 57: ...R32 Product Information Sheet MSZ EF VGK DoC UK2021B45 MSZ EF25 50VG MUZ EF25 50VG Declaration of Conformity CE2019B01 MSZ EF25 50VG MUZ EF25 50VG Installation Manual JG79J334H01 MUZ EF25 50VG Parts List OBB832 MUZ EF25 50VG Service Manual OBH832 ...

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