Mitsubishi Electric MUZ-HJ25VA Service Manual Download Page 43

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OPERATING PROCEDURE

PHOTOS

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

board

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

ing connectors:

CN721 (R.V. coil)
CN771 (Fan motor)
CN641 (Defrost thermistor and discharge temperature

thermistor)

CN724 (LEV)

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

the separator.

(5) Remove the inverter assembly.
(6) Remove the screw of the earth wire and the screw of

the terminal block support.

(7) Remove the screw of the terminal block and remove

the terminal block.

(8) Remove the heat sink support from the P.C. board

support.

(9) Unhook the catch of the inverter P.C. board and

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

3. Removing the R.V. coil

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

CN721 (R.V. coil)

(3) Remove the R.V. coil.

Photo 4

Photo 5 (Inverter assembly)

Heat sink

P.C. board

support

Screws of the terminal

block support and the

back panel

Screw of the

heat sink and the

separator

Inverter

P.C. board

Screw of the

earth wire

Heat sink

support

Screw of the

terminal block support

Terminal block

support

OBH648A

Summary of Contents for MUZ-HJ25VA

Page 1: ...TROL 24 10 SERVICE FUNCTIONS 25 11 TROUBLESHOOTING 25 12 DISASSEMBLY INSTRUCTIONS 42 Models SPLIT TYPE AIR CONDITIONERS MUZ HJ25VA E1 MUZ HJ35VA E1 MUZ HJ50VA E1 HFC utilized R410A No OBH648 REVISED EDITION A OUTDOOR UNIT Indoor unit service manual MSZ HJ VA Series OBH647 NOTE RoHS compliant products have G mark on the spec name plate PARTS CATALOG OBB648 MUZ HJ25VA MUZ HJ35VA Revision A MUZ HJ50V...

Page 2: ... 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 or fire when the unit is being used serviced or disposed of Correc...

Page 3: ...model 1 TECHNICAL CHANGES ACCESSORIES Air outlet Drain outlet Piping Drain hose Air inlet Back and side MUZ HJ25VA MUZ HJ35VA Drain socket 1 2 PART NAMES AND FUNCTIONS Air outlet Drain outlet Piping Drain hose Air inlet Back and side MUZ HJ50VA OBH648A ...

Page 4: ...HC Output W 500 550 Current 1 Cooling A 3 3 4 4 Heating 3 8 4 4 Refrigeration oil Model L 0 32 NEO22 Fan motor Model RA6V21 BD Current 1 A 0 23 Dimensions W H D mm 699 538 249 Weight kg 24 25 Special remarks Dehumidification Cooling L h 0 4 0 6 Air flow 1 m3 h 1 890 1 890 Sound level 1 Cooling dB A 50 50 Heating 50 50 Fan speed rpm 840 840 Fan speed regulator 1 1 Refrigerant filling capacity R410A...

Page 5: ...C0J50 FA Current 1 Cooling A 0 27 Heating 0 34 Dimensions W H D mm 800 550 285 Weight kg 36 Special remarks Dehumidification Cooling L h 2 2 Air flow 1 Cooling High m3 h 1 872 Med 1 872 Low 1 086 Heating High 2 088 Med 1 776 Low 1 386 Sound level 1 Cooling dB A 50 Heating 51 Fan speed Cooling High rpm 810 Med 810 Low 490 Heating High 900 Med 770 Low 610 Fan speed regulator 3 Refrigerant filling ca...

Page 6: ... PTC64 33 Ω Terminal block TB 3 P Relay X61 3 A 250 V X63 3 A 250 V X64 20 A 250 V R V coil 21S4 220 240 VAC Specifications and rated conditions of main electric parts Model Item MUZ HJ50VA Smoothing capacitor C61 C62 C63 600 μF 620 μF 420 V Diode module DB61 15 A 600 V Fuse F61 T20AL250V F701 F801 F901 T3 15AL250V Power module IC700 15 A 600 V IC820 20A 600V IC932 8A600V Expansion valve coil LEV ...

Page 7: ...E BAND SOUND PRESSURE LEVEL dB re 0 0002 MICRO BAR BAND CENTER FREQUENCIES Hz COOLING FUNCTION SPL dB A LINE HEATING 50 50 Test conditions Cooling Dry bulb temperature 35 C Heating Dry bulb temperature 7 C Wet bulb temperature 6 C OUTDOOR UNIT MICROPHONE 1m NC 10 MUZ HJ35VA 4 NOISE CRITERIA CURVES 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 OCT...

Page 8: ...Liquid refrigerant pipe joint Refrigerant pipe flared ø6 35 Gas refrigerant pipe joint Refrigerant pipe flared ø9 52 4 3 3 5 2 10 X 21 Oval hole REQUIRED SPACE 350 mm or more 100 mm or more Drain hole ø42 100 mm or more 100 mm or more 200 mm or more 41 5 270 3 157 7 4 3 4 0 102 7 13 5 538 Air in Air in Air out 349 5 55 7 121 4 249 17 9 699 500 121 259 Bolt pitch for installation 294 267 285 19 6 L...

Page 9: ...9 MUZ HJ25VA 6 WIRING DIAGRAM MUZ HJ35VA OBH648A ...

Page 10: ...10 MUZ HJ50VA OBH648A ...

Page 11: ...eat insulator R V coil heating OFF cooling ON Strainer 100 Capillary tube ø3 0 ø1 4 260 LEV Muffler HJ35 only 7 REFRIGERANT SYSTEM DIAGRAM Outdoor heat exchanger Flared connection Defrost thermistor RT61 Discharge temperature thermistor RT62 Flared connection Stop valve with strainer Stop valve with service port Refrigerant flow in cooling Compressor Muffler Muffler 4 way valve Refrigerant flow in...

Page 12: ... B Indoor unit Outdoor unit ADDITIONAL REFRIGERANT CHARGE R410A g Model Outdoor unit precharged Refrigerant piping length one way 5 m 6 m 7 m 8 m 9 m 10 m 11 m 12 m 13 m 14 m 15 m 20 m MUZ HJ25VA MUZ HJ35VA MUZ HJ50VA 700 0 0 0 20 40 60 80 100 120 140 160 260 720 1 150 Calculation X g 20 g m Refrigerant piping length m 7 NOTE Refrigerant piping exceeding 7 m requires additional refrigerant charge ...

Page 13: ...d the indoor outlet air wet and dry bulb temperature for your reference at service Cooling Heating MUZ HJ25VA MUZ HJ35VA MUZ HJ50VA 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 The thermomete...

Page 14: ...ulb temperature difference C Outdoor intake air Dry bulb temperature C MUZ HJ25VA MUZ HJ35VA 6 1 5 6 5 1 4 6 4 1 3 6 6 8 6 2 5 6 5 1 4 5 4 0 MUZ HJ50VA 9 6 8 7 7 9 7 1 6 3 5 5 18 20 25 30 35 46 45 40 0 8 0 9 1 0 1 1 1 2 1 3 Total input Cooling at Rated frequency Input correction factor 22 20 18 Indoor intake air Wet bulb temperature C 26 24 8 1 CAPACITY AND INPUT CURVES Indoor air Wet bulb tempera...

Page 15: ...f Heating capacity Capacity correction factors The operational frequency of compressor MUZ HJ25VA MUZ HJ35VA MUZ HJ50VA Hz Hz Hz Hz Correction of Cooling capacity Capacity correction factors The operational frequency of compressor Correction of Cooling total input Input correction factors The operational frequency of compressor Correction of Heating total input Input correction factors The operati...

Page 16: ...operation Both indoor and outdoor unit are under the same tempera ture humidity condition Operation TEST RUN OPERATION Refer to 8 3 8 4 OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT Condition Operation Test run operation refer to 8 3 HEAT operation 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...

Page 17: ... 723 27 24 3 35 1 98 0 59 664 3 23 1 90 0 59 701 3 15 1 86 0 59 723 3 05 1 80 0 59 759 27 26 3 45 1 62 0 47 701 3 35 1 57 0 47 737 3 30 1 55 0 47 759 3 20 1 50 0 47 781 28 18 2 94 2 91 0 99 584 2 81 2 78 0 99 613 2 70 2 67 0 99 642 2 60 2 57 0 99 672 28 20 3 06 2 66 0 87 613 2 94 2 56 0 87 650 2 85 2 48 0 87 664 2 75 2 39 0 87 694 28 22 3 19 2 39 0 75 635 3 08 2 31 0 75 675 3 00 2 25 0 75 694 2 88...

Page 18: ... 818 2 38 1 69 0 71 847 27 24 2 88 1 70 0 59 803 2 70 1 59 0 59 839 2 55 1 50 0 59 876 27 26 3 03 1 42 0 47 832 2 85 1 34 0 47 869 2 68 1 26 0 47 905 28 18 2 45 2 43 0 99 715 2 25 2 23 0 99 759 2 08 2 05 0 99 788 28 20 2 58 2 24 0 87 745 2 40 2 09 0 87 781 2 23 1 94 0 87 825 28 22 2 73 2 04 0 75 774 2 55 1 91 0 75 818 2 38 1 78 0 75 847 28 24 2 88 1 81 0 63 803 2 70 1 70 0 63 839 2 55 1 61 0 63 87...

Page 19: ...4 4 22 2 41 0 57 946 4 06 2 32 0 57 998 3 97 2 26 0 57 1030 3 84 2 19 0 57 1082 27 26 4 35 1 96 0 45 998 4 22 1 90 0 45 1050 4 16 1 87 0 45 1082 4 03 1 81 0 45 1113 28 18 3 70 3 59 0 97 832 3 54 3 44 0 97 874 3 40 3 30 0 97 915 3 28 3 18 0 97 957 28 20 3 86 3 28 0 85 874 3 70 3 15 0 85 926 3 59 3 05 0 85 946 3 47 2 95 0 85 988 28 22 4 02 2 93 0 73 905 3 87 2 83 0 73 962 3 78 2 76 0 73 988 3 62 2 6...

Page 20: ...2 99 2 06 0 69 1206 27 24 3 62 2 06 0 57 1144 3 40 1 94 0 57 1196 3 21 1 83 0 57 1248 27 26 3 81 1 72 0 45 1186 3 59 1 62 0 45 1238 3 37 1 52 0 45 1290 28 18 3 09 2 99 0 97 1019 2 84 2 75 0 97 1082 2 61 2 54 0 97 1123 28 20 3 24 2 76 0 85 1061 3 02 2 57 0 85 1113 2 80 2 38 0 85 1175 28 22 3 43 2 51 0 73 1102 3 21 2 35 0 73 1165 2 99 2 18 0 73 1206 28 24 3 62 2 21 0 61 1144 3 40 2 08 0 61 1196 3 21...

Page 21: ...7 24 6 70 2 68 0 40 1866 6 45 2 58 0 40 1968 6 30 2 52 0 40 2030 6 10 2 44 0 40 2132 27 26 6 90 1 93 0 28 1968 6 70 1 88 0 28 2071 6 60 1 85 0 28 2132 6 40 1 79 0 28 2194 28 18 5 88 4 70 0 80 1640 5 63 4 50 0 80 1722 5 40 4 32 0 80 1804 5 20 4 16 0 80 1886 28 20 6 13 4 17 0 68 1722 5 88 4 00 0 68 1825 5 70 3 88 0 68 1866 5 50 3 74 0 68 1948 28 22 6 38 3 57 0 56 1784 6 15 3 44 0 56 1896 6 00 3 36 0...

Page 22: ...4 75 2 47 0 52 2378 27 24 5 75 2 30 0 40 2255 5 40 2 16 0 40 2358 5 10 2 04 0 40 2460 27 26 6 05 1 69 0 28 2337 5 70 1 60 0 28 2440 5 35 1 50 0 28 2542 28 18 4 90 3 92 0 80 2009 4 50 3 60 0 80 2132 4 15 3 32 0 80 2214 28 20 5 15 3 50 0 68 2091 4 80 3 26 0 68 2194 4 45 3 03 0 68 2317 28 22 5 45 3 05 0 56 2173 5 10 2 86 0 56 2296 4 75 2 66 0 56 2378 28 24 5 75 2 53 0 44 2255 5 40 2 38 0 44 2358 5 10...

Page 23: ...INPUT Q INPUT Q INPUT Q INPUT 15 2 27 647 2 74 776 3 20 876 3 67 945 4 14 1005 4 57 1035 5 04 1055 21 2 16 697 2 59 826 3 06 915 3 49 985 3 96 1035 4 39 1065 4 84 1104 26 1 94 746 2 41 876 2 84 965 3 31 1035 3 78 1085 4 21 1114 4 68 1144 MUZ HJ50VA CAPACITY 5 4 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 40 962 4 10 1154 4...

Page 24: ... OFF The fan motor turns OFF 15 seconds after the compressor has stopped running 9 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 protection Defrost thermistor Cooling High pressure protect...

Page 25: ...A MUZ HJ50VA 10 2 PRE HEAT CONTROL SETTING PRE HEAT CONTROL When moisture gets into the refrigerant cycle it may interfere the start up of the compressor at low discharge tempera ture The pre heat control prevents this interference The pre heat control turns ON when the discharge temperature is 20 C or below When the pre heat control turns ON the compressor is energized About 50 W JK When the JK w...

Page 26: ...The indoor unit is abnormal Check the blinking pattern and identify the abnormal point with the indoor unit failure mode table Refer to indoor unit service manual Make sure to check at least two 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 Press RESET butt...

Page 27: ...ck the blinking pattern and identify the abnormal point with the out door unit failure mode table 11 2 3 Make sure to check at least two 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 Press RESET button of the remote controller Repair the failure parts The o...

Page 28: ... minutes later Check refrigerant circuit and refrigerant amount Refer to 11 5 Check of LEV 6 time flash 2 5 seconds OFF High pressure Temperature indoor coil thermistor exceeds 70 C in HEAT mode Temperature defrost thermistor exceeds 70 C in COOL mode Check refrigerant circuit and refrigerant amount Check stop valve 7 time flash 2 5 seconds OFF Fin temperature P C board temperature 7 time flash 2 ...

Page 29: ...normal ity The waveform of compressor current is distorted Reconnect connector of compressor Refer to 11 5 How to check in verter compressor 13 10 time flash 2 5 seconds OFF MUZ HJ50VA Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds after outdoor fan start up Refer to 11 5 Check of outdoor fan motor Refer to 11 5 Check of inverter P C board 14 12 time flash 2 5 seconds...

Page 30: ... RA6V21 AB 152 0 5 C CUT OFF RA6V21 BB 126 2 CUT OFF Measure the resistance between the terminals with a tester Part temperature 10 40 C MUZ HJ25VA MUZ HJ35VA Color of lead wire Normal RA6V21 AB RA6V21 BB BD WHT BLK 305 374 Ω 222 272 Ω BLK RED 247 304 Ω 245 300 Ω MUZ HJ50VA Outdoor fan motor MF MUZ HJ50VA Color of lead wire Normal RED BLK BLK WHT WHT RED 30 43 Ω R V coil 21S4 Measure the resistanc...

Page 31: ...he balance of voltage between the terminals Output voltage is 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 8 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 ...

Page 32: ...al open NOTE Be sure to zero the ohmmeter before measurement Measure the resistance between the lead wires at 3 points Connect the compressor and activate the inverter Then measure the time until the inverter stops due to over current Operation method Start heating or cooling operation by pressing EMERGENCY OPERATION switch on the indoor unit TEST RUN OPERATION Refer to 8 3 Measurement Measure the...

Page 33: ...C board Voltage between outdoor terminal block S1 S2 Is the thermistor normal Refer to 11 6 1 Reconnect the connector of thermistor Turn ON the power supply and press EMERGENCY OPERATION switch No Replace the thermistor except RT64 When RT64 is abnormal replace the inverter P C board Does the unit operate for 10 minutes or more without showing thermistor abnormality OK Cause is poor contact Replac...

Page 34: ...e power module Turn ON the power supply and press EMERGENCY OPERATION switch twice HEAT mode Disconnect connector CN61 between the compressor and the power module Turn ON the power supply and press EMERGENCY OPERATION switch once COOL mode Is there 230 VAC between CN721 and on the inverter P C board 3 minutes after the power supply is turned ON No Yes Replace the inverter P C board Replace the 4 w...

Page 35: ...verter P C board Yes No Yes No I Check of outdoor fan motor MUZ HJ25VA MUZ HJ35VA MUZ HJ50VA Is the resistance between each ter minal of outdoor fan motor normal Refer to 11 4 Disconnect CN932 from the inverter P C board and turn on the power supply Rotate the outdoor fan motor manually and measure the voltage of CN931 Between 1 and 5 Between 2 and 5 Between 3 and 5 Does the voltage between each t...

Page 36: ...l the expansion valve vibrate on touching it Turn ON the power supply Preparation of the remote controller While pressing both OPERATION SELECT button and TOO COOL button on the remote controller at the same time press RESET button First release RESET button Hold down the other two buttons for another 3 seconds Make sure that the indicators on the LCD screen shown in the right figure are all displ...

Page 37: ...an 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 11 3 Yes No Yes 10 time flash No L Check of inverter P C board MUZ HJ50VA OBH648A ...

Page 38: ...the inverter P C board in the outdoor unit repeat 3 6 second OFF and 0 8 second ON quick blinking for 3 minutes after the outdoor unit is energized Check the blinking pattern within 3 minutes after LED is turned on Af ter 3 minutes LED will blink 6 times whether the inverter P C board in the outdoor unit is normal or not No Replace the inverter P C board in the outdoor unit 2 Yes A 2 Be careful of...

Page 39: ...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 40: ...esistance kΩ 1 Inverter P C board MUZ HJ25VA MUZ HJ35VA 11 6 TEST POINT DIAGRAM AND VOLTAGE Back side of unit Fin temperature thermistor RT64 CN642 Discharge temperature thermistor RT62 CN641 Defrost thermistor RT61 CN641 230 VAC Jumper wire for changing defrost setting JS Front side of unit DB61 250 V 370 VDC Output to drive compressor LDW LDV LDU LED Fuse F801 T3 15AL250V Jumper wire for pre hea...

Page 41: ...temperature thermistor RT64 CN642 Discharge temperature thermistor RT62 CN641 Defrost thermistor RT61 CN641 DB61 250 370 VDC Front side of unit 230 VAC Smoothing capacitor C62 Output to drive compressor LDU LDV LDW Fuse F701 T3 15AL250V Smoothing capacitor C61 Smoothing capacitor C63 Fuse F901 T3 15AL250V R V coil CN721 230 VAC Jumper wire for changing defrost setting JS Signal of outdoor fan moto...

Page 42: ...the top panel Screws of the top panel 1 Slide the sleeve and check if there is a locking 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 Terminal with locking mechanism Detaching points The terminal which has the locking mechan...

Page 43: ...e terminal block support 7 Remove the screw of the terminal block and remove the terminal block 8 Remove the heat sink support from the P C board support 9 Unhook the catch of the inverter P C board and remove the inverter P C board from the P C board support 3 Removing the R V coil 1 Remove the cabinet and the panels Refer to 1 2 Disconnect the following connectors Inverter P C board CN721 R V co...

Page 44: ...mpressor and the 4 way valve 1 Remove the cabinet and the panels Refer to 1 2 Remove the inverter assembly Refer to 2 3 Remove the screws of the reactor and remove the reactor 4 Remove the screws of the separator and remove the separator 5 Remove the soundproof felt 6 Remove the terminal cover and the compressor lead wire 7 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes u...

Page 45: ...5 Remove the top panel 6 Remove the screws fixing the cabinet 7 Remove the cabinet 8 Remove the fixing screws of the terminal block support and the back panel 9 Remove the screws fixing the back panel 10 Remove the back panel Photo 1 Photo 2 45 Back panel Service panel Screws of the top panel Screws of the cabinet Screws of the top panel Screw of the service panel Direction to remove Screws of the...

Page 46: ...mbly Photo 5 3 Removing the R V coil 1 Remove the cabinet and the panels Refer to 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 and outdoor heat exchanger tem perature thermistor 1 Remove the cabinet and the panels Refer to 1 2 Disconnect the lead wire to the reactor and the followi...

Page 47: ...reactor 4 Remove the screws of the separator and remove the separa tor 5 Remove the soundfproof felt 6 Remove the terminal cover and the compressor lead wire 7 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes until the pressure gauge shows 0 kg cm2 0 MPa 8 Detach the brazed part of the suction and the discharge pipe connected with the compressor 9 Detach the brazed part of ...

Page 48: ...ributed in Mar 2013 No OBH648 REVISED EDITION A Distributed in Dec 2012 No OBH648 Made in Japan New publication effective Mar 2013 Specifications are subject to change without notice HEAD OFFICE TOKYO BLDG 2 7 3 MARUNOUCHI CHIYODA KU TOKYO 100 8310 JAPAN ...

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