Mitsubishi Electric MUFZ-KW25VG-E1 Service Manual Download Page 51

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MUFZ-KW50VGHZ MUFZ-KW60VGHZ

-20

-10

100

Temperature (°C)

Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)

10 20 30 40 50 60 70 80

100

120

140

160

180

200

Temperature(°C)

Fin temperature thermistor(RT64)

Resistance(k )

Temperature (°C)

Discharge temperature thermistor (RT62)

Resistance (kΩ)

100

200

300

400

500

600

700

800

10 20 30 40 50 60 70 80 90 100 110 120

Fin temperature
thermistor/RT64
(CN673)

Ambient temperature
thermistor/RT65
(CN672)

Discharge temperature
thermistor/RT62
(CN671)
Defrost thermistor
/RT61 (CN671)

Output to
drive outdoor
fan motor
(CN932)

Outdoor heat exchanger
temperature thermistor
/RT68 (CN671)

Fuse (F901)
T3.15AL250V

Fuse (F880)
T3.15AL250V

LEV (CN724)

Jumper wire for
changing defrost
setting (JS)

Jumper wire for
pre-heat control
setting (JK)

Fuse (F601)
T3.15AL250V

Signal of out-
door fan motor
(CN931)

R.V. coil (CN602)
230 V AC

230 V AC

325 - 370 V DC

IC700 (N)

IC700 (P)

LED

Heater (CN601)
230 V AC

OBH895

Summary of Contents for MUFZ-KW25VG-E1

Page 1: ...NTS 1 TECHNICAL CHANGES 2 2 SERVICING PRECAUTIONS FOR UNITS USING REFRIGERANT R32 3 3 PART NAMES AND FUNCTIONS 5 4 SPECIFICATION 6 5 NOISE CRITERIA CURVES 9 6 OUTLINES AND DIMENSIONS 10 7 WIRING DIAGRAM 12 8 REFRIGERANT SYSTEM DIAGRAM 13 9 PERFORMANCE CURVES 15 10 ACTUATOR CONTROL 29 11 SERVICE FUNCTIONS 30 12 TROUBLESHOOTING 31 13 DISASSEMBLY INSTRUCTIONS 52 MUFZ KW25VGHZ MUFZ KW35VGHZ No OBH895 ...

Page 2: ...f the power supply breaker and pull the power plug Discharge the capacitor before the work involving the electric parts Precautions during the repair service Do not perform the work involving the electric parts with wet hands Do not 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 ...

Page 3: ...e being changed they shall be fit for the purpose and to the correct specification At all times the manufacturer s mainte nance 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 ref...

Page 4: ... familiar with the equipment and all its detail It is recommended good prac tice 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 1 Become familiar with the equipment and its ...

Page 5: ...VGHZ MUFZ KW35VGHZ PART NAMES AND FUNCTIONS Piping Air outlet Drain outlet Air inlet Back and side Drain hose 3 Air outlet Drain outlet Piping Drain hose Air inlet Back and side MUFZ KW50VGHZ MUFZ KW60VGHZ OBH895 ...

Page 6: ...r Model RC0J50 NC Current 1 Cooling A 0 25 0 25 Heating 0 22 0 22 Dimensions W H D mm 800 550 285 Weight kg 35 Special remarks Dehumidification Cooling L h 0 6 1 4 Airflow Cooling High m3 h 1 962 1 962 Low 984 984 Heating High 1 962 1 962 Medium 1 638 1 638 Low 1 356 1 356 Sound level 1 Cooling dB A 47 47 Heating 46 47 Fan speed Cooling High rpm 900 900 Low 490 490 Heating High 900 900 Medium 760 ...

Page 7: ...Fan motor Model RC0J60 BC Current 1 Cooling A 0 68 0 83 Heating 0 74 0 84 Dimensions W H D mm 840 880 330 Weight kg 54 54 Special remarks Dehumidification Cooling L h 2 2 2 3 Airflow Cooling High m3 h 2 628 2 928 Low 1 716 1 716 Heating High 3 078 3 078 Medium 2 778 3 078 Low 2 280 2 280 Sound level 1 Cooling dB A 50 52 Heating 54 56 Fan speed Cooling High rpm 760 820 Low 450 450 Heating High 860 ...

Page 8: ...02 3 A 250 V R V coil 21S4 220 240 V AC Heater protector 26H Open 45 C Specifications and rated conditions of main electric parts Model Item MUFZ KW25VGHZ MUFZ KW35VGHZ Smoothing capacitor C61 C62 C63 600 µF 620 µF 420 V Diode module DB61 15 A 600 V DB65 25A 600V Fuse F701 F801 F901 T3 15AL250V F61 25 A 250 V F62 15 A 250 V Defrost heater H 230 V 60 W Power module IC700 20A 600V IC932 5 A 600 V Ex...

Page 9: ...0 63 125 250 500 1000 2000 4000 8000 NC 60 NC 50 NC 40 NC 30 NC 20 NC 70 BAND CENTER FREQUENCIES Hz NC 10 OCTAVE BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR COOLING FUNCTION SPL dB A LINE HEATING 50 54 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 NC 10 OCTAVE BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR COOLIN...

Page 10: ...10 OUTLINES AND DIMENSIONS 6 Unit mm MUFZ KW25VGHZ MUFZ KW35VGHZ OBH895 ...

Page 11: ... 195 3 5 4 4 Liquid refrigerant pipe joint Refrigerant pipe flared Ø 6 35 Gas refrigerant pipe joint Refrigerant pipe flared Ø 12 7 Air in 350 mm or more 100 mm or more REQUIRED SPACE 100 mm or more 500 mm or more 2 1 500 mm or more when front and sides of the unit are clear 2 When any 2 sides of left right and rear of the unit are clear Clear 1 OBH895 ...

Page 12: ...12 WIRING DIAGRAM 7 MUFZ KW25VGHZ MUFZ KW35VGHZ MUFZ KW50VGHZ MUFZ KW60VGHZ OBH895 ...

Page 13: ...Outdoor heat exchanger temperature thermistor RT68 Strainer 100 Muffler REFRIGERANT SYSTEM DIAGRAM 8 MUFZ KW25VGHZ MUFZ KW35VGHZ MUFZ KW50VGHZ MUFZ KW60VGHZ Muffler Outdoor heat exchanger Flared connection Defrost thermistor RT61 Discharge temperature thermistor RT62 Flared connection Stop valve Stop valve Capillary tube ø4 0 ø2 4 100 Refrigerant flow in cooling Compressor 4 way valve Refrigerant ...

Page 14: ... REFRIGERANT CHARGE R32 g Model Outdoor unit precharged Refrigerant piping length one way 7 m 8 m 9 m 10 m 11 m 12 m 13 m 14 m 15 m 16 m 17 m 18 m 19 m 20 m MUFZ KW25VGHZ MUFZ KW35VGHZ 1 000 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Calculation X g 20 g m Refrigerant piping length m 7 Model Outdoor unit precharged Refrigerant piping length one way 7 m 8 m 9 m 10 m 15 m 20 m 25 m 30 m MUFZ ...

Page 15: ...utlet air wet and dry bulb temperature for your reference at service 4 GUARANTEED OUTDOOR TEMPERATURE COOLING DB WB 10 46 HEATING DB WB 25 24 18 How to measure the indoor air wet and 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 T...

Page 16: ...5 40 45 Outdoor intake air Dry bulb temperature C Input correction factors 26 24 22 20 18 Total input Cooling at Rated frequency Outdoor intake air Wet bulb temperature C 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 25 20 Indoor intake air Dry bulb temperature Indoor air Dry bulb temperature difference C 22 9 21 2...

Page 17: ...0 0 0 1 0 2 0 3 0 MUFZ KW25VGHZ Correction of Cooling capacity The operational frequency of compressor Hz Capacity correction factors Correction of Cooling input The operational frequency of compressor Hz Input correction factors Correction of Heating capacity The operational frequency of compressor Hz Capacity correction factors Correction of Heating input The operational frequency of compressor ...

Page 18: ...e 10 0 14 2 16 0 18 0 12 0 7 0 11 0 13 0 15 0 9 0 15 20 25 30 35 0 7 0 9 1 1 1 3 1 5 MUFZ KW35VGHZ 50 60 70 Ambient temperature C Ambient humidity 7 0 11 0 13 0 15 0 9 0 kgf cm2 Gauge MPa Gauge NOTE The unit of pressure has been changed to MPa on the international system of units SI unit system The conversion factor is 1 MPa Gauge 10 2 kgf cm2 Gauge Outdoor unit current 50 60 70 50 60 70 MUFZ KW25...

Page 19: ...0 6 5 7 0 7 5 8 0 8 5 0 5 10 15 20 25 4 2 4 6 5 0 5 4 5 8 6 2 Outdoor unit current MUFZ KW50VGHZ MUFZ KW25VGHZ Ambient temperature C Outdoor current A Ambient temperature C Outdoor current A MUFZ KW35VGHZ Ambient temperature C Outdoor current A MUFZ KW60VGHZ Ambient temperature C Outdoor current A 0 5 10 15 20 25 4 2 4 6 5 0 5 4 5 8 6 2 0 5 10 15 20 25 5 5 6 0 6 5 7 0 7 5 8 0 OBH895 ...

Page 20: ...66 564 27 24 3 35 1 81 0 54 519 3 23 1 74 0 54 547 3 15 1 70 0 54 564 3 05 1 65 0 54 593 27 26 3 45 1 45 0 42 547 3 35 1 41 0 42 576 3 30 1 39 0 42 593 3 20 1 34 0 42 610 28 18 2 94 2 76 0 94 456 2 81 2 64 0 94 479 2 70 2 54 0 94 502 2 60 2 44 0 94 524 28 20 3 06 2 51 0 82 479 2 94 2 41 0 82 507 2 85 2 34 0 82 519 2 75 2 26 0 82 542 28 22 3 19 2 23 0 70 496 3 08 2 15 0 70 527 3 00 2 10 0 70 542 2 ...

Page 21: ...66 638 2 38 1 57 0 66 661 27 24 2 88 1 55 0 54 627 2 70 1 46 0 54 656 2 55 1 38 0 54 684 27 26 3 03 1 27 0 42 650 2 85 1 20 0 42 678 2 68 1 12 0 42 707 28 18 2 45 2 30 0 94 559 2 25 2 12 0 94 593 2 08 1 95 0 94 616 28 20 2 58 2 11 0 82 581 2 40 1 97 0 82 610 2 23 1 82 0 82 644 28 22 2 73 1 91 0 70 604 2 55 1 79 0 70 638 2 38 1 66 0 70 661 28 24 2 88 1 67 0 58 627 2 70 1 57 0 58 656 2 55 1 48 0 58 ...

Page 22: ...54 891 27 24 4 69 1 97 0 42 819 4 52 1 90 0 42 864 4 41 1 85 0 42 891 4 27 1 79 0 42 936 27 26 4 83 1 45 0 30 864 4 69 1 41 0 30 909 4 62 1 39 0 30 936 4 48 1 34 0 30 963 28 18 4 11 3 37 0 82 720 3 94 3 23 0 82 756 3 78 3 10 0 82 792 3 64 2 98 0 82 828 28 20 4 29 3 00 0 70 756 4 11 2 88 0 70 801 3 99 2 79 0 70 819 3 85 2 69 0 70 855 28 22 4 46 2 59 0 58 783 4 31 2 50 0 58 833 4 20 2 44 0 58 855 4 ...

Page 23: ...3 1 80 0 54 1044 27 24 4 03 1 69 0 42 990 3 78 1 59 0 42 1035 3 57 1 50 0 42 1080 27 26 4 24 1 27 0 30 1026 3 99 1 20 0 30 1071 3 75 1 12 0 30 1116 28 18 3 43 2 81 0 82 882 3 15 2 58 0 82 936 2 91 2 38 0 82 972 28 20 3 61 2 52 0 70 918 3 36 2 35 0 70 963 3 12 2 18 0 70 1017 28 22 3 82 2 21 0 58 954 3 57 2 07 0 58 1008 3 33 1 93 0 58 1044 28 24 4 03 1 85 0 46 990 3 78 1 74 0 46 1035 3 57 1 64 0 46 ...

Page 24: ... 27 24 6 70 2 68 0 40 1238 6 45 2 58 0 40 1306 6 30 2 52 0 40 1346 6 10 2 44 0 40 1414 27 26 6 90 1 93 0 28 1306 6 70 1 87 0 28 1374 6 60 1 84 0 28 1414 6 40 1 79 0 28 1455 28 18 5 88 4 70 0 80 1088 5 63 4 50 0 80 1142 5 40 4 32 0 80 1197 5 20 4 16 0 80 1251 28 20 6 13 4 16 0 68 1142 5 88 3 99 0 68 1210 5 70 3 87 0 68 1238 5 50 3 74 0 68 1292 28 22 6 38 3 57 0 56 1183 6 15 3 44 0 56 1258 6 00 3 36...

Page 25: ...3 4 75 2 47 0 52 1578 27 24 5 75 2 30 0 40 1496 5 40 2 16 0 40 1564 5 10 2 04 0 40 1632 27 26 6 05 1 69 0 28 1550 5 70 1 59 0 28 1618 5 35 1 50 0 28 1686 28 18 4 90 3 92 0 80 1333 4 50 3 60 0 80 1414 4 15 3 32 0 80 1469 28 20 5 15 3 50 0 68 1387 4 80 3 26 0 68 1455 4 45 3 02 0 68 1537 28 22 5 45 3 05 0 56 1442 5 10 2 85 0 56 1523 4 75 2 66 0 56 1578 28 24 5 75 2 53 0 44 1496 5 40 2 37 0 44 1564 5 ...

Page 26: ... 27 24 8 17 3 61 0 44 1574 7 87 3 48 0 44 1661 7 69 3 40 0 44 1713 7 44 3 29 0 44 1799 27 26 8 42 2 71 0 32 1661 8 17 2 63 0 32 1747 8 05 2 59 0 32 1799 7 81 2 51 0 32 1851 28 18 7 17 6 04 0 84 1384 6 86 5 78 0 84 1453 6 59 5 55 0 84 1522 6 34 5 34 0 84 1592 28 20 7 47 5 40 0 72 1453 7 17 5 18 0 72 1540 6 95 5 02 0 72 1574 6 71 4 85 0 72 1644 28 22 7 78 4 68 0 60 1505 7 50 4 52 0 60 1600 7 32 4 41...

Page 27: ...8 5 80 3 26 0 56 2007 27 24 7 02 3 10 0 44 1903 6 59 2 91 0 44 1990 6 22 2 75 0 44 2076 27 26 7 38 2 38 0 32 1972 6 95 2 24 0 32 2059 6 53 2 10 0 32 2145 28 18 5 98 5 03 0 84 1695 5 49 4 62 0 84 1799 5 06 4 26 0 84 1868 28 20 6 28 4 54 0 72 1765 5 86 4 23 0 72 1851 5 43 3 92 0 72 1955 28 22 6 65 4 00 0 60 1834 6 22 3 75 0 60 1938 5 80 3 49 0 60 2007 28 24 7 02 3 38 0 48 1903 6 59 3 18 0 48 1990 6 ...

Page 28: ... 2 88 1065 3 40 1174 3 96 1258 4 52 1319 5 03 1355 5 59 1392 MUFZ KW50VGHZ CAPACITY 6 0 kW INPUT 1600 W INDOOR DB C OUTDOOR WB C 25 20 15 10 5 0 5 10 15 20 Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT 15 1 50 432 2 28 640 3 00 832 3 78 1040 4 56 1248 5 34 1408 6 12 1520 6 90 1616 7 62 1664 8 40 1696 21 1 38 464 2 10 672 2 82 880 3 60 1120 4 32 1328 5 10 1472 5 82...

Page 29: ...compressor has stopped running ACTUATOR CONTROL 10 MUFZ KW25VGHZ MUFZ KW35VGHZ MUFZ KW50VGHZ MUFZ KW60VGHZ 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 Defro...

Page 30: ...t 50 W MUFZ KW50 60 Prolonged low load operation in which the thermostat is OFF for a long time at low outside temperature 0 C or less may cause the following troubles To prevent those troubles activate the pre heat control 1 If moisture gets into the refrigerant cycle and freezes it may interfere the startup of the compressor 2 If liquid refrigerant collects in the compressor a failure in the com...

Page 31: ... 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 chec...

Page 32: ... 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 failure mode recall function Release the failure mode recall function by the following procedures Turn OFF the power supply and turn it ON agai...

Page 33: ... 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 failure mode aga...

Page 34: ...0 Reconnect compressor connector Refer to 12 5 How to check inverter compressor Check stop valve Compressor synchronous abnormality Compressor startup 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 Temperature of discharge te...

Page 35: ...LTAGE on the service manual of indoor and outdoor unit for the characteristics of the thermistors Do not start the operation again without repair to prevent hazards 16 time blink 2 5 seconds OFF 1 Outdoor refrigerant system abnormality 1 time blink 2 5 seconds OFF A closed valve and air trapped in the refrigerant circuit are detected based on the temperature sensed by the indoor and outdoor thermi...

Page 36: ... Fin temperature P C board tem perature thermistor overheat protection Temperature of fin temperature thermistor on the heat sink ex ceeds 75 86 C KW25 35 75 80 C KW50 60 or tempera ture of P C board temperature thermistor on the inverter P C board exceeds 72 85 C KW25 35 70 75 C KW50 60 Check around outdoor unit Check outdoor unit air passage Refer to 12 5 Check of outdoor fan motor 12 5 time bli...

Page 37: ... power supply voltage is high KW50 60 Zero cross detecting circuit Zero cross signal cannot be detected It occurs with following cases 1 Instantaneous power voltage drop Short time power failure 2 Distortion of primary voltage Refer to 12 5 Check of power supply 23 9 time blink 2 5 seconds OFF Inverter check mode The connector of compressor is disconnected inverter check mode starts Check if the c...

Page 38: ...n terminals using a tester Temperature 10 to 40 C Normal Ω MUFZ KW25VGHZ MUFZ KW35VGHZ MUFZ KW50VGHZ MUFZ KW60VGHZ U V U W V W 0 82 1 11 0 87 1 18 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 MUFZ KW25VGHZ MUFZ KW35VGHZ MUFZ KW50VGHZ MUFZ KW60VGHZ RED BLK BLK WHT WHT RED 32 43 25 34 W U V WHT RED BLK R ...

Page 39: ...0 130V The voltage may differ according to the tester Operation method Start cooling or heating operation by pressing the emergency operation switch on the indoor unit TEST RUN OPERATION 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 ...

Page 40: ...fer 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 seconds 10 seconds 10 minute...

Page 41: ...istance of thermistor MUFZ KW25VGHZ MUFZ KW35VGHZ 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 CN642 pin1 and pin2 Ambient temperature RT65 Between CN643 pin1 and pin2 Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3 MUFZ KW50VGHZ MUFZ KW60V...

Page 42: ...urn ON the power supply and press the emergency operation switch once COOL mode First of all measure the resistance of R V coil to check if the coil is defective Refer to 12 4 In case CN602 is disconnected or R V coil is open voltage is generated between the terminal pins of the connector although no signal is being transmitted to R V coil Check if CN602 is connected Is there 230 V AC between CN60...

Page 43: ...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 0V 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 the...

Page 44: ...ht up or blink Refer to 12 6 1 No Replace the inverter P C board Is there bus bar voltage 260 370V DC between DB61 and DB61 MUFZ KW25 35VGHZ 325 370 V DC between IC700 P and N MUFZ KW50 60VGHZ 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 the ...

Page 45: ...e 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 Pr...

Page 46: ...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 OBH895 ...

Page 47: ...supply OFF Replace the indoor power P C board Start the emergency operation No Yes Repair completed Does DC 20 V or more occur between indoor terminal block S2 and S3 No Yes Replace the outdoor inverter P C board Replace the indoor electronic control P C board 2 Electric charge may remain immediately after the power supply is turned OFF Perform the procedure after 3 minutes Replace the outdoor inv...

Page 48: ...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 49: ...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 50: ...80 90 100110120 Fin temperature thermistor RT64 CN642 Ambient temperature thermistor RT65 CN643 Discharge temperature thermistor RT62 CN641 Defrost thermistor RT61 CN641 DB61 260 370 V DC Front side of unit 230 V AC Smoothing capacitor C62 Output to drive compressor LDU LDV LDW Fuse F701 T3 15AL250V Smoothing capacitor C61 Fuse F901 T3 15AL250V R V coil CN721 230 V AC Jumper wire for changing defr...

Page 51: ...100 200 300 400 500 600 700 800 0 10 20 30 40 50 60 70 80 90 100110120 Fin temperature thermistor RT64 CN673 Ambient temperature thermistor RT65 CN672 Discharge temperature thermistor RT62 CN671 Defrost thermistor RT61 CN671 Output to drive outdoor fan motor CN932 Outdoor heat exchanger temperature thermistor RT68 CN671 Fuse F901 T3 15AL250V Fuse F880 T3 15AL250V LEV CN724 Jumper wire for changing...

Page 52: ... locking mechanism Slide the sleeve Pull the terminal while pushing the locking lever Hold the sleeve and pull out the terminal slowly Connector Sleeve Locking lever Back panel Service panel Screws of the top panel Screws of the terminal block support and the back panel Screws of the cabinet Screws of the back panel Screws of the top panel Direction to remove Screws of the cabinet Hooks of the ser...

Page 53: ...ion procedure when attaching the inverter P C board Photo 5 1 Connect the lead wires of the heat exchanger temperature thermistor to the connector on the inverter P C board Pull the lead wires of the heat exchanger temperature thermis tor toward you and put them on the left hook on the P C board support so that the other lead wires are bundled up as shown in Photo 5 2 Connect the lead wires of the...

Page 54: ...tor 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 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 ...

Page 55: ...rcuit 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 compressor nuts 6 Remove the compressor 7 Detach the brazed part of pipes connected with 4 way valve Photo 9 55 Brazed parts of 4 way valve Suction pipe brazed part Discharge pipe brazed part Discharge temperature ...

Page 56: ... service panel 5 Remove the top panel 6 Remove the valve cover 7 Disconnect the power supply cord and indoor outdoor con necting 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 56 Screws of the cabinet Screws of the top panel Screws of the cabinet Screws of the top panel Screws of the service panel Screw o...

Page 57: ...he earth wires and the lead wires of the inverter P C board 5 Remove the screws of the P B support 6 Remove the P B support from the relay panel 7 Remove the screws of the inverter P C board 8 Remove the inverter P C board from P B support Notes about attaching the inverter P C board 1 When attaching the inverter P C board clip the lead wires of the reactor to the wire saddles on the bottom of rel...

Page 58: ...ire to the reactor and the following connectors Inverter P C board CN671 Defrost thermistor discharge temperature thermis tor and outdoor heart exchanger temperature ther mistor CN672 Ambient temperature thermistor 3 Pull out the discharge temperature thermistor from its hold er Photo 9 4 Pull out the defrost thermistor from its holder 5 Pull out the outdoor heat exchanger temperature thermistor f...

Page 59: ... 1 2 Remove the back panel Refer to section 1 3 Remove the screws fixing the relay panel 4 Remove the relay panel 5 Remove the inverter assembly Refer to section 2 6 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes until the pressure gauge shows 0 kg cm2 0 MPa 7 Detach the brazed part of the suction and the discharge pipe connected with compressor 8 Remove the compressor nu...

Page 60: ...ht 2021 MITSUBISHI ELECTRIC CORPORATION Published Jul 2021 No OBH895 Made in Japan Specifications are subject to change without notice HEAD OFFICE TOKYO BUILDING 2 7 3 MARUNOUCHI CHIYODA KU TOKYO 100 8310 JAPAN ...

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Mitsubishi Electric MUFZ-KW25VG-E1, Service Manual

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