Mitsubishi Electric MUZ-DM25VA Service Manual Download Page 41

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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)

CN931, CN932 (Fan motor)

CN641 (Defrost thermistor and discharge temperature

thermistor)

CN643 (Ambient temperature thermistor)

CN644 (Outdoor heat exchanger temperature thermis-

tor)

CN724 (LEV)

(3) Remove the compressor connector (CN61).

(4) Remove the screw fixing the heat sink support and the

separator.

(5) Remove the inverter assembly.

(6) Remove the screws of the earth wire and 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

Screws of the terminal

block support and the

back panel

Screw of the heat

sink support and

the separator

Photo 5 (Inverter assembly)

Heat sink

P.C. board

support

Inverter

P.C. board

Heat sink

support

Screws of the earth wire and

the terminal block support

Terminal block

support

Soundproof

felt

OBH751

Summary of Contents for MUZ-DM25VA

Page 1: ...E CRITERIA CURVES 6 5 OUTLINES AND DIMENSIONS 7 6 WIRING DIAGRAM 8 7 REFRIGERANT SYSTEM DIAGRAM 9 8 PERFORMANCE CURVES 10 9 ACTUATOR CONTROL 20 10 SERVICE FUNCTIONS 21 11 TROUBLESHOOTING 22 12 DISASSEMBLY INSTRUCTIONS 40 HFC utilized R410A Indoor unit service manual MSZ DM VA Series OBH750 NOTE RoHS compliant products have G mark on the spec name plate PARTS CATALOG OBB751 ...

Page 2: ... 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 specif ed refrigerant only Never use any refrigerant other than that specified Doing so may cause a burst an explosion or fire when the unit is bei...

Page 3: ...3 2 PART NAMES AND FUNCTIONS ACCESSORIES Air outlet Drain outlet Piping Drain hose Air inlet Back and side MUZ DM25VA MUZ DM35VA Drain socket 1 OBH751 ...

Page 4: ...MC Output W 500 550 Current 1 Cooling A 3 3 4 4 Heating 3 8 4 4 Refrigeration oil Model L 0 27 FV50S Fan motor Model RC0J20 AA Current 1 A 0 26 Dimensions W H D mm 699 538 249 Weight kg 24 25 Special remarks Dehumidif cation Cooling L h 0 4 0 6 Air f ow 1 m3 h 1 890 Sound level 1 Cooling dB A 50 51 Heating 50 51 Fan speed rpm 840 Fan speed regulator 1 Refrigerant f lling capacity R410A kg 0 70 0 7...

Page 5: ... 420 V Diode module DB61 15 A 600 V DB65 25 A 600 V Fuse F701 F801 F901 T3 15AL250V Power module IC700 10 A 600 V Expansion valve coil LEV 12 VDC Reactor L61 18 mH Switching power transistor Q821 30 A 600 V Circuit protection PTC65 33 Ω Terminal block TB 3 P Relay X63 3 A 250 V X64 20 A 250 V R V coil 21S4 220 240 VAC OBH751 ...

Page 6: ...0 NC 10 MUZ DM25VA 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 51 51 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 DM35VA 4 N...

Page 7: ... 2 sides of left right and rear of the unit are clear Clear 1 200 mm or more 2 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 Liquid refrigerant pipe joint Refrigerant pipe flared ø6 35 Gas refrigerant pipe joint Refrigerant pipe flared ø9 52 Drain hole ø33 2 10 3 X 19 3 Oval hole OBH751 ...

Page 8: ...8 MUZ DM25VA MUZ DM35VA 6 WIRING DIAGRAM OBH751 ...

Page 9: ... REFRIGERANT SYSTEM DIAGRAM 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 DM25VA MUZ DM35VA 20 12 9 52 6 35 Max Length A Max Height difference 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 ...

Page 10: ...ure and the indoor outlet air wet and dry bulb temperature for your reference at service Cooling Heating MUZ DM25VA MUZ DM35VA 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 thermometers mu...

Page 11: ... 4 0 Total input Cooling at Rated frequency Input correction factor 22 20 18 18 20 25 30 35 40 46 45 0 8 0 9 1 0 1 1 1 2 1 3 Indoor intake air Wet bulb temperature C 26 24 Indoor intake air Dry bulb temperature C Outdoor intake air Wet bulb temperature C Outdoor intake air Wet bulb temperature C Indoor intake air Dry bulb temperature C Heating capacity at Rated frequency Total input Heating at Rat...

Page 12: ... The operational frequency of compressor Correction of Heating capacity Capacity correction factors The operational frequency of compressor 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...

Page 13: ...Gauge 50 18 32 60 70 C Ambient temperature C Ambient humidity kgf cm2 Gauge MPa Gauge 50 18 32 60 70 C Ambient temperature C Ambient humidity 15 20 25 30 35 0 4 0 5 0 6 0 7 0 8 0 9 15 20 25 30 35 0 3 0 4 0 5 0 6 0 7 0 8 COOL 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 C...

Page 14: ...t current Ambient temperature C Outdoor current A Ambient temperature C Outdoor current A MUZ DM35VA MUZ DM25VA Condition Operation Test run operation refer to 8 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 OBH751 ...

Page 15: ... 703 27 24 3 35 1 98 0 59 646 3 23 1 90 0 59 682 3 15 1 86 0 59 703 3 05 1 80 0 59 738 27 26 3 45 1 62 0 47 682 3 35 1 57 0 47 717 3 30 1 55 0 47 738 3 20 1 50 0 47 760 28 18 2 94 2 91 0 99 568 2 81 2 78 0 99 596 2 70 2 67 0 99 625 2 60 2 57 0 99 653 28 20 3 06 2 66 0 87 596 2 94 2 56 0 87 632 2 85 2 48 0 87 646 2 75 2 39 0 87 675 28 22 3 19 2 39 0 75 618 3 08 2 31 0 75 657 3 00 2 25 0 75 675 2 88...

Page 16: ... 795 2 38 1 69 0 71 824 27 24 2 88 1 70 0 59 781 2 70 1 59 0 59 817 2 55 1 50 0 59 852 27 26 3 03 1 42 0 47 809 2 85 1 34 0 47 845 2 68 1 26 0 47 880 28 18 2 45 2 43 0 99 696 2 25 2 23 0 99 738 2 08 2 05 0 99 767 28 20 2 58 2 24 0 87 724 2 40 2 09 0 87 760 2 23 1 94 0 87 802 28 22 2 73 2 04 0 75 753 2 55 1 91 0 75 795 2 38 1 78 0 75 824 28 24 2 88 1 81 0 63 781 2 70 1 70 0 63 817 2 55 1 61 0 63 85...

Page 17: ...4 4 22 2 41 0 57 928 4 06 2 32 0 57 979 3 97 2 26 0 57 1010 3 84 2 19 0 57 1061 27 26 4 35 1 96 0 45 979 4 22 1 90 0 45 1030 4 16 1 87 0 45 1061 4 03 1 81 0 45 1091 28 18 3 70 3 59 0 97 816 3 54 3 44 0 97 857 3 40 3 30 0 97 898 3 28 3 18 0 97 938 28 20 3 86 3 28 0 85 857 3 70 3 15 0 85 908 3 59 3 05 0 85 928 3 47 2 95 0 85 969 28 22 4 02 2 93 0 73 887 3 87 2 83 0 73 944 3 78 2 76 0 73 969 3 62 2 6...

Page 18: ... 2 99 2 06 0 69 1183 27 24 3 62 2 06 0 57 1122 3 40 1 94 0 57 1173 3 21 1 83 0 57 1224 27 26 3 81 1 72 0 45 1163 3 59 1 62 0 45 1214 3 37 1 52 0 45 1265 28 18 3 09 2 99 0 97 1000 2 84 2 75 0 97 1061 2 61 2 54 0 97 1102 28 20 3 24 2 76 0 85 1040 3 02 2 57 0 85 1091 2 80 2 38 0 85 1153 28 22 3 43 2 51 0 73 1081 3 21 2 35 0 73 1142 2 99 2 18 0 73 1183 28 24 3 62 2 21 0 61 1122 3 40 2 08 0 61 1173 3 2...

Page 19: ... 944 26 1 70 638 2 11 748 2 49 825 2 90 884 3 31 927 3 69 952 4 10 978 MUZ DM35VA CAPACITY 3 6 kW INPUT 975 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 2 27 634 2 74 761 3 20 858 3 67 926 4 14 985 4 57 1014 5 04 1034 21 2 16 683 2 59 809 3 06 897 3 49 965 3 96 1014 4 39 1043 4 84 1082 26 1 94 731 2 41 858 2 84 946 3 31 1014 3 78 1063 4 21...

Page 20: ... interlocking with the compressor ON The fan motor turns ON 5 seconds before the compressor starts up 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 Co...

Page 21: ...ce The pre heat control turns ON when the discharge temperature thermis tor is 20 C or below When pre heat control turns ON 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 the JK wire of the inverter P C board Refer to 11 6 1 NOTE When the inverter P C board is...

Page 22: ...g capacitor 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 MUZ DM25VA MUZ DM35VA 11 TROUBLESHOOTING 3 Troubleshooting procedure 1 Check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indica...

Page 23: ...oor unit is abnormal Check the blinking pattern and identify the abnormal point by referring to the indoor unit failure 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 Press RESET bu...

Page 24: ...he blinking pattern and identify the abnormal point by referring to the outdoor unit failure mode table 11 2 3 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 Press RESET button of the remote controller Repair the failure parts T...

Page 25: ...hronous abnormality Compressor start up failure protection 12 time f ash 2 5 seconds OFF Waveform of compressor current is distorted Reconnect compressor connector Refer to 11 5 How to check inverter compressor 5 time f ash 2 5 seconds OFF Discharge temperature Temperature of discharge temperature thermistor exceeds 116 C compressor stops Compressor can restart if discharge temperature thermistor ...

Page 26: ...lve Closed valve 14 time f ash 2 5 seconds OFF Closed valve is detected by compressor current Check stop valve 4 way valve Pipe temperature 16 time f ash 2 5 seconds OFF The 4 way valve does not work properly The indoor coil thermistor detects an abnormal temperature Check 4 way valve Replace inverter P C board Outdoor refrigerant system abnormality 17 time f ash 2 5 seconds OFF A closed valve and...

Page 27: ... erant amount Refer to 11 5 Check of LEV 10 4 time f ash 2 5 seconds OFF Fin temperature P C board tem perature thermistor overheat protection Temperature of f n temperature thermistor on the heat sink exceeds 80 C or temperature of P C board temperature ther mistor on the inverter P C board exceeds 78 C Check around outdoor unit Check outdoor unit air passage Refer to 11 5 Check of outdoor fan mo...

Page 28: ...tion 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 22 9 time f ash 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 11 5 How to check inverter compressor NO...

Page 29: ...or the chart of thermistor Compressor MC Measure the resistance between the terminals with a tester Part temperature 10 40 C Normal U V U W V W MUZ DM25VA MUZ DM35VA 2 01 2 86 Ω 1 20 1 72 Ω Outdoor fan motor MF Measure the resistance between lead wires with a tester Part temperature 10 40 C Color of lead wire Normal RED BLK BLK WHT WHT RED 85 90 Ω R V coil 21S4 Measure the resistance between the t...

Page 30: ...the 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 31: ...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 overcurrent 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 32: ...utdoor 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 Replace the inverter P C board ...

Page 33: ...Replace 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 VAC 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 CN61 between the compressor and the power mod...

Page 34: ...nector CN61 between compressor and power transistor module Turn ON the power supply and press the EMERGENCY OPERATION switch Does the upper lamp of OPERATION INDICATOR lamp on the indoor unit light up After 3 minutes is there voltage 230 VAC between CN771 and on the inverter P C board Replace the outdoor fan motor Replace the inverter P C board Yes No Yes No I Check of outdoor fan motor OBH751 ...

Page 35: ... the expansion valve vibrate when 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 2 buttons for another 3 seconds Make sure that the indicators on the LCD screen shown in the right f gure are all displa...

Page 36: ...es the LED on 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...

Page 37: ...r 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 f x the leak CAUTION Do not...

Page 38: ...he installation condition combination of specif c 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 39: ...M25VA MUZ DM35VA 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 heat control setting JK 230 VAC LEV connec...

Page 40: ... the top panel Screws of the top panel Screws of the motor support 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...

Page 41: ... screws of the earth wire and 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...

Page 42: ...holder Photo 9 5 Pull out the outdoor heat exchanger temperature ther mistor from its holder 6 Pull out the ambient temperature thermistor from its holder 5 Removing the outdoor fan motor 1 Remove the cabinet and the panels Refer to 1 2 Disconnect the following connectors Inverter P C board CN931 CN932 Fan motor 3 Remove the fan motor lead wire from where it is fas tened on the separator 4 Remove ...

Page 43: ... 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 dis charge pipe connected with the compressor 9 Detach the brazed part of pipes connected with the 4 way valve 10 Remove the nuts of compressor legs 11 Remove the compressor 43 Photo 9 D...

Page 44: ... ELECTRIC CORPORATION Distributed in Dec 2015 No OBH751 Made in Japan New publication effective Dec 2015 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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Mitsubishi Electric MUZ-DM25VA, Service Manual

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