Mitsubishi Electric MUZ-LN25VGHZ Service Manual Download Page 49

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1. Inverter P.C. board

12-6. TEST POINT DIAGRAM AND VOLTAGE

MUZ-LN25VGHZ MUZ-LN35VGHZ

-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)

5HVLVWDQFHN

100

200

300

400

500

600

700

800

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

Fin temperature thermistor/R

T64

(CN642)

Ambient temperature thermistor/R

T65

(CN643)

Discharge temperature thermistor/R

T62

(CN641)

Defrost thermistor /R

T61(CN641)

DB61
260 - 370VDC

Front side of unit

230\VAC

Smoothing
capacitor
(C62)

Smoothing
capacitor
(C63)

Output to
drive
compressor
(LDU,
LDV,
LDW)

(+)

(-)

Fuse (F701)
T3.15AL250V

Smoothing
capacitor
(C61)
(

LN35VGHZ

)

Fuse (F901)
T3.15AL250V

R.V. coil
(CN721)
230VAC

Jumper wire for
changing defrost
setting (JS)

Signal of outdoor fan motor (CN931)

230VAC

Outdoor heat exchanger temperature thermistor /R

T68 (CN644)

Jumper wire
for pre-heat
control setting
(JK)

Fuse (F801)
T3.15AL250V

Back side of unit

LEV (CN724)

Output to
drive outdoor
fan motor
(CN932)

LED

OBH768

Summary of Contents for MUZ-LN25VGHZ

Page 1: ...N35VGHZ E1 ER1 ET1 MUZ LN50VGHZ E1 ER1 ET1 CONTENTS 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 14 9 PERFORMANCE CURVES 16 10 ACTUATOR CONTROL 28 11 SERVICE FUNCTIONS 29 12 TROUBLESHOOTING 30 13 DISASSEMBLY INSTRU...

Page 2: ...ed or disposed of Correct refrigerant is specified in the manuals and on the spec labels provided with our products We will not be held responsible for mechanical failure system malfunction unit breakdown or accidents caused by failure to follow the instructions MUZ LN25VGHZ E1 ER1 ET1 MUZ LN35VGHZ E1 ER1 ET1 MUZ LN50VGHZ E1 ER1 ET1 1 New model TECHNICAL CHANGES 1 OBH768 ...

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: ...MUZ LN25VGHZ MUZ LN35VGHZ 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 MUZ LN50VGHZ OBH768 ...

Page 6: ...l Model L 0 35 FW68S 0 35 FW68S Fan motor Model RC0J50 RB Current 1 Cooling A 0 26 0 29 Heating 0 22 0 22 Dimensions W H D mm 800 550 285 Weight kg 35 36 Special remarks Dehumidification Cooling L h 0 1 0 5 Air flow 1 Cooling High m3 h 2 124 Low 978 Heating High 2 028 Med 1 734 Low 1 302 Sound level 1 Cooling dB A 46 49 Heating 49 50 Fan speed Cooling High rpm 940 Low 460 Heating High 900 Med 780 ...

Page 7: ... motor Model RC0J60 BC Current 1 Cooling A 0 83 Heating 0 84 Dimensions W H D mm 840 880 330 Weight kg 55 Special remarks Dehumidification Cooling L h 1 7 Air flow 1 Cooling High m3 h 3 006 Low 1 716 Heating High 3 006 Med 2 892 Low 2 280 Sound level 1 Cooling dB A 51 Heating 54 Fan speed Cooling High rpm 840 Low 450 Heating High 840 Med 810 Low 650 Fan speed regulator 3 Refrigerant filling capaci...

Page 8: ...V X64 20 A 250 V X66 3 A 250 V X69 10 A 230 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 MUZ LN50VGHZ Smoothing capacitor CB1 CB2 CB3 560 μF 450 V Fuse F601 F880 F901 T3 15AL250V Switching power transistor Q3A Q3B 21 A 650 V Defrost heater H 230V 120 W Power module IC932 5 A 600 V IC700 20 A 600 V Expansion valve ...

Page 9: ...CIES Hz NC 10 OCTAVE BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR COOLING FUNCTION SPL dB A LINE HEATING 51 54 MUZ LN25VGHZ MUZ LN50VGHZ NOISE CRITERIA CURVES 5 Test conditions Cooling Dry bulb temperature 35 C Heating Dry bulb temperature 7 C Wet bulb temperature 6 C OUTDOOR UNIT MICROPHONE 1 m 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 B...

Page 10: ...10 OUTLINES AND DIMENSIONS 6 Unit mm MUZ LN25VGHZ MUZ LN35VGHZ OBH768 ...

Page 11: ...5 4 4 Liquid refrigerant pipe joint Refrigerant pipe flared Ø 6 35 Gas refrigerant pipe joint Refrigerant pipe flared Ø 9 52 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 OBH768 ...

Page 12: ...12 WIRING DIAGRAM 7 MUZ LN25VGHZ MUZ LN35VGHZ OBH768 ...

Page 13: ...13 MUZ LN50VGHZ OBH768 ...

Page 14: ...2 4 240 Outdoor heat exchanger temperature thermistor RT68 Strainer 100 Muffler REFRIGERANT SYSTEM DIAGRAM 8 MUZ LN25VGHZ MUZ LN35VGHZ MUZ LN50VGHZ 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 flow in h...

Page 15: ... 30 15 9 52 6 35 ADDITIONAL REFRIGERANT CHARGE R32 g Model Outdoor unit precharged Refrigerant piping length one way 7 m 11 m 12 m 13 m 14 m 15 m 16 m 17 m 18 m 20 m MUZ LN25 35VGHZ 1 000 0 80 100 120 140 160 180 200 220 260 Calculation X g 20 g m Refrigerant piping length m 7 Model Outdoor unit precharged Refrigerant piping length one way 7 m 16 m 17 m 20 m 25 m 30 m MUZ LN50VGHZ 1 450 0 180 200 ...

Page 16: ...s 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 fil...

Page 17: ...16 2 14 7 13 2 11 7 10 3 8 8 7 3 5 9 25 0 23 1 21 1 19 2 17 3 15 4 13 5 11 5 9 6 7 7 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 Indoor intake air Dry bulb temperature MUZ LN25VGHZ MUZ LN35VGHZ MUZ LN50VGHZ Indoor air Dry bulb temperature difference C 14 5 13 4 12 3 11 2 ...

Page 18: ...ut correction factors Correction of Heating capacity The operational frequency of compressor Hz Capacity correction factors Correction of Heating input The operational frequency of compressor Hz Input correction factors Correction of Cooling capacity The operational frequency of compressor Hz Capacity correction factors Correction of Cooling input The operational frequency of compressor Hz Input c...

Page 19: ... 3 1 6 1 9 2 2 2 5 15 20 25 30 35 2 0 2 3 2 6 2 9 3 2 3 5 15 20 25 30 35 3 0 3 5 4 0 4 5 5 0 5 5 15 20 25 30 35 1 08 1 10 1 12 1 14 1 16 15 20 25 30 35 0 89 0 90 0 91 0 92 0 93 15 20 25 30 35 1 01 1 02 1 03 1 04 1 05 MUZ LN25VGHZ 50 60 70 Ambient temperature C Ambient humidity Outdoor low pressure kgf cm2 Gauge MPa Gauge MUZ LN50VGHZ 50 60 70 Ambient temperature C Ambient humidity kgf cm2 Gauge MP...

Page 20: ... Outdoor unit current Ambient temperature C Outdoor current A MUZ LN35VGHZ Ambient temperature C Outdoor current A MUZ LN50VGHZ Ambient temperature C Outdoor current A Condition Operation Test run operation Refer to 9 3 HEAT operation Indoor Outdoor Dry bulb temperature C 20 0 2 7 15 20 0 Wet bulb temperature C 14 5 1 6 12 14 5 OBH768 ...

Page 21: ...9 480 27 24 3 35 2 24 0 67 441 3 23 2 16 0 67 466 3 15 2 11 0 67 480 3 05 2 04 0 67 504 27 26 3 45 1 90 0 55 466 3 35 1 84 0 55 490 3 30 1 82 0 55 504 3 20 1 76 0 55 519 28 18 2 94 2 94 1 00 388 2 81 2 81 1 00 407 2 70 2 70 1 00 427 2 60 2 60 1 00 446 28 20 3 06 2 91 0 95 407 2 94 2 79 0 95 432 2 85 2 71 0 95 441 2 75 2 61 0 95 461 28 22 3 19 2 65 0 83 422 3 08 2 55 0 83 449 3 00 2 49 0 83 461 2 8...

Page 22: ...9 543 2 38 1 88 0 79 563 27 24 2 88 1 93 0 67 534 2 70 1 81 0 67 558 2 55 1 71 0 67 582 27 26 3 03 1 66 0 55 553 2 85 1 57 0 55 577 2 68 1 47 0 55 601 28 18 2 45 2 45 1 00 475 2 25 2 25 1 00 504 2 08 2 08 1 00 524 28 20 2 58 2 45 0 95 495 2 40 2 28 0 95 519 2 23 2 11 0 95 548 28 22 2 73 2 26 0 83 514 2 55 2 12 0 83 543 2 38 1 97 0 83 563 28 24 2 88 2 04 0 71 534 2 70 1 92 0 71 558 2 55 1 81 0 71 5...

Page 23: ...2 812 27 24 4 69 2 81 0 60 746 4 52 2 71 0 60 787 4 41 2 65 0 60 812 4 27 2 56 0 60 853 27 26 4 83 2 32 0 48 787 4 69 2 25 0 48 828 4 62 2 22 0 48 853 4 48 2 15 0 48 877 28 18 4 11 4 11 1 00 656 3 94 3 94 1 00 689 3 78 3 78 1 00 722 3 64 3 64 1 00 754 28 20 4 29 3 77 0 88 689 4 11 3 62 0 88 730 3 99 3 51 0 88 746 3 85 3 39 0 88 779 28 22 4 46 3 39 0 76 713 4 31 3 27 0 76 759 4 20 3 19 0 76 779 4 0...

Page 24: ...918 3 33 2 39 0 72 951 27 24 4 03 2 42 0 60 902 3 78 2 27 0 60 943 3 57 2 14 0 60 984 27 26 4 24 2 03 0 48 935 3 99 1 92 0 48 976 3 75 1 80 0 48 1017 28 18 3 43 3 43 1 00 804 3 15 3 15 1 00 853 2 91 2 91 1 00 886 28 20 3 61 3 17 0 88 836 3 36 2 96 0 88 877 3 12 2 74 0 88 927 28 22 3 82 2 90 0 76 869 3 57 2 71 0 76 918 3 33 2 53 0 76 951 28 24 4 03 2 58 0 64 902 3 78 2 42 0 64 943 3 57 2 28 0 64 98...

Page 25: ... 27 24 6 70 3 15 0 47 1256 6 45 3 03 0 47 1325 6 30 2 96 0 47 1366 6 10 2 87 0 47 1435 27 26 6 90 2 42 0 35 1325 6 70 2 35 0 35 1394 6 60 2 31 0 35 1435 6 40 2 24 0 35 1477 28 18 5 88 5 11 0 87 1104 5 63 4 89 0 87 1159 5 40 4 70 0 87 1214 5 20 4 52 0 87 1270 28 20 6 13 4 59 0 75 1159 5 88 4 41 0 75 1228 5 70 4 28 0 75 1256 5 50 4 13 0 75 1311 28 22 6 38 4 02 0 63 1201 6 15 3 87 0 63 1277 6 00 3 78...

Page 26: ... 4 75 2 80 0 59 1601 27 24 5 75 2 70 0 47 1518 5 40 2 54 0 47 1587 5 10 2 40 0 47 1656 27 26 6 05 2 12 0 35 1573 5 70 2 00 0 35 1642 5 35 1 87 0 35 1711 28 18 4 90 4 26 0 87 1352 4 50 3 92 0 87 1435 4 15 3 61 0 87 1490 28 20 5 15 3 86 0 75 1408 4 80 3 60 0 75 1477 4 45 3 34 0 75 1559 28 22 5 45 3 43 0 63 1463 5 10 3 21 0 63 1546 4 75 2 99 0 63 1601 28 24 5 75 2 93 0 51 1518 5 40 2 75 0 51 1587 5 1...

Page 27: ...PUT Q INPUT Q INPUT Q INPUT Q INPUT 15 2 52 520 3 04 624 3 56 704 4 08 760 4 60 808 5 08 832 5 60 848 21 2 40 560 2 88 664 3 40 736 3 88 792 4 40 832 4 88 856 5 38 888 26 2 16 600 2 68 704 3 16 776 3 68 832 4 20 872 4 68 896 5 20 920 MUZ LN50VGHZ CAPACITY 6 0 kW INPUT 1480 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 78 962 4 56 1154 5 3...

Page 28: ...rns OFF 15 seconds after the compressor 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 Discharge temperature thermistor Protection Indoor coil temperature thermistor Cooling Coil frost prevention Heating High pressure protec tion Defrost thermistor Heating Defrosting Fin temperature thermistor Pr...

Page 29: ... W MUZ LN50 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 compressor ...

Page 30: ...or 4 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 flashing on and off to indicate an abnormality To make sure ...

Page 31: ...indoor unit is abnormal Check the blinking pattern and identify the abnormal point by referring to the indoor unit failure recall mode table 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 again Pres...

Page 32: ...on 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 again acco...

Page 33: ... Compressor synchronous abnormality Compressor startup failure protection 12 time flash 2 5 seconds OFF Waveform of compressor current is distorted Reconnect compressor connector Refer to 12 5 How to check inverter compressor 5 time flash 2 5 seconds OFF Discharge temperature Temperature of discharge temperature thermistor exceeds 116 C compressor stops Compressor can restart if discharge temperat...

Page 34: ...rrent of compressor cannot be detected normally 14 time flash or more 2 5 seconds OFF Stop valve Closed valve 14 time flash 2 5 seconds OFF Closed valve is detected by compressor current Check stop valve 4 way valve Pipe temperature 16 time flash 2 5 seconds OFF The 4 way valve does not work properly The indoor coil thermistor detects an abnormal temperature Check the 4 way valve Replace the inver...

Page 35: ...erature P C board tem perature thermistor overheat protection Temperature of fin temperature thermistor on the heat sink exceeds 75 86 C LN25 35 75 80 C LN50 or tempera ture of P C board temperature thermistor on the inverter P C board exceeds 72 85 C LN25 35 70 75 C LN50 Check around outdoor unit Check outdoor unit air passage Refer to 12 5 Check of outdoor fan motor 12 5 time flash 2 5 seconds O...

Page 36: ...he power supply voltage is high MUZ LN50 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 flash 2 5 seconds OFF Inverter check mode The connector of compressor is disconnected inverter check mode starts Check if th...

Page 37: ...rt of thermistor Compressor Measure the resistance between terminals using a tester Temperature 10 40 C Normal Ω MUZ LN25VGHZ MUZ LN35VGHZ MUZ LN50VGHZ U V U W V W 1 60 2 17 0 82 1 11 0 87 1 18 Outdoor fan motor Measure the resistance between lead wires using a tester Temperature 10 40 C Color of lead wire Normal Ω MUZ LN25 35VGHZ MUZ LN50VGHZ RED BLK BLK WHT WHT RED 15 20 25 34 R V coil 21S4 Meas...

Page 38: ...50 130V 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 th...

Page 39: ...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 40: ...sure the resistance of thermistor MUZ LN25 35VGHZ 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 MUZ LN50VGHZ Thermistor ...

Page 41: ...GBT module IC700 Turn ON the power supply and press 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 230VAC ...

Page 42: ...measure 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 0VDC No No Yes Disconnect the connectors CN931 and CN932 from the inverter P C board Check the connection between the ...

Page 43: ...board light up or flash Refer to 12 6 1 No Replace the inverter P C board Is there bus bar voltage 260 370V DC between DB61 and DB61 MUZ LN25 35VGHZ 325 370VDC between IC700 P and N MUZ LN50VGHZ 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: ...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 Prepara...

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 flash 10 times Replace the inverter P C board Check the corresponding parts following LED indication Refer to 12 3 Yes No Yes 10 time flash No L Check of inverter P C board OBH768 ...

Page 46: ... POWER lamp blink continuously 6 minutes after the emergency operation starts No Does the outdoor LED light up Replace the indoor electronic control P C board Replace the indoor electronic control P C board Replace the indoor power P C board Yes Yes Does the outdoor LED blink 6 times Yes Confirm that the thermostat is OFF and wiring is not loose No Does DC 6 V or more occur between indoor terminal...

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: ... 20 30 40 50 60 70 80 90 100110120 Fin temperature thermistor RT64 CN642 Ambient temperature thermistor RT65 CN643 Discharge temperature thermistor RT62 CN641 Defrost thermistor RT61 CN641 DB61 260 370VDC Front side of unit 230 VAC Smoothing capacitor C62 Smoothing capacitor C63 Output to drive compressor LDU LDV LDW Fuse F701 T3 15AL250V Smoothing capacitor C61 LN35VGHZ Fuse F901 T3 15AL250V R V ...

Page 50: ...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 def...

Page 51: ...ng lever or not 2 The terminal with this connector has the 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 ...

Page 52: ...ure 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 expansion...

Page 53: ...istor 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 an...

Page 54: ...ecover 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 54 Brazed parts of 4 way valve Suction pipe brazed part Discharge pipe brazed part Discharge temperature thermistor O...

Page 55: ...nel 6 Remove the valve cover 7 Disconnect the power supply and indoor outdoor connect ing wire and the demand control signal transmission cable 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 55 Screws of the cabinet Screws of the top panel Screws of the cabinet Screws of the top panel Screws of the service pan...

Page 56: ...d 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 relay panel 2 After attaching...

Page 57: ...he 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 from its ...

Page 58: ...move the inverter assembly Refer to 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 nuts 9 Remove the compressor 10 Detach the brazed parts of 4 way valve and pipe Photo 6 58 Brazed part of the discharge pipe Bra...

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Mitsubishi Electric MUZ-LN25VGHZ, Service Manual

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