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SERVICE MANUAL MUZ-HJ25VA - E1 MUZ

1. NOTE Q Total capacity kW SHF Sensible heat factor DB Dry bulb temperature SHC Sensible heat capacity kW INPUT Total power input W WB Wet bulb temperature OBH648 PERFORMANCE DATA COOL operation at Rated frequency MUZ HJ35VA CAPACITY 3 15 kW SHF 0 87 INPUT 1040 W OUTDOOR DB C 25 27 INDOOR INDOOR DB C WB C NOTE Q Total capacity kW SHF Sensible heat factor DB Dry bulb temperature SHC Sensible heat capacity kW INPUT Total power input W WB Wet bulb temperature OBH648 gt PERFORMANCE DATA COOL operation at Rated frequency MUZ HJ35VA CAPACITY 3 15 kW SHF 0 87 INPUT 1040 W OUTDOOR DB C 40 INDOOR INDOOR DB C WB C NOTE Q Total capacity kW SHF Sensible heat factor DB Dry bulb temperature SHC Sensible heat capacity kW INPUT Total power input W WB Wet bulb temperature OBH648 PERFORMANCE DATA HEAT operation at Rated frequency MUZ HJ25VA CAPACITY 3 15 kW INPUT 870 W OUTDOOR WB C INDOOR 7 5 DB C INPUT Q INPUT 15 766 827 21 800 861 26 844 905 MUZ HJ35VA CAPACITY 3 6 kW INPUT 995 W OUTDOOR C 0 5 INPUT Q INPUT 15
2. WHTEI Color of lead wire Normal eor Expansion valve coil LEV WHT RED ORNE RED ORN 37 540 2 V YLW BRN BRN BLU gt a OBH648 3 11 5 TROUBLESHOOTING FLOW How to check inverterlcompressor Disconnect the connector CN61 between compressor and the power module IC700 Y Check the voltage between terminals 177 See 11 5 Check of open phase v Are the voltages balanced No Replace the inverter P C board Yes Check compressor See 11 5 Check of compressor Check of open phase e With the connector between the compressor and the power module disconnected activate the inverter and check if the in verter is normal by measuring the balance of voltage between the terminals Output voltage is 50 130 V The voltage may differ according to the tester lt lt Operation method gt gt Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the indoor unit TEST RUN OPERA TION Refer to 8 3 lt lt Measurement point gt gt At 3 points BLK U WHT V Measure AC voltage between the lead wires at 3 points 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 the inverter P C board f
3. Max Length Max Height difference A B Gas Liquid MUZ HJ25VA MUZ HJ35VA 20 12 9 52 6 35 Indoor unit Max Height difference B Max Length A Outdoor unit ADDITIONAL REFRIGERANT CHARGE R410A g Outdoor unit Refrigerant piping length one way precharged 8m 9m 10m 11m 12m 13m 20 40 60 80 100 120 Model MUZ HJ25VA 700 MUZ HJ35VA 720 Calculation X g 7 20 g m x Refrigerant piping length m 7 NOTE Refrigerant piping exceeding 7 m requires additional refrigerant charge according to the calculation OBH648 i 8 PERFORMANCE CURVES MUZ HJ25VA MUZ HJ35VA The standard specifications apply only to the operation of the air conditioner under normal conditions Since operating condi tions vary according to the areas where these units are installed the following information has been provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve 1 GUARANTEED VOLTAGE 198 264 V 50 Hz 2 AIR FLOW Air flow should be set at MAX 3 MAIN READINGS 1 Indoor intake air wet bulb temperature C WB 2 Indoor outlet air wet bulb temperature C WB Cooling 3 Outdoor intake air dry bulb temperature C DB 4 Total input W 5 Indoor intake air dry bulb temperature C DB 6 Outdoor intake air wet bulb temperature C WB
4. E A n 250 RED 1 About the indoor side electric p 2 71 6 Q ll wiring refer to the indoor RT64 RTL RTE unit electric wiring diagram for servicing 2 Use copper conductors only For field wiring LEV SYMBOL NAME SYMBOL NAME SYMBOL NAME CONNECTOR IC821 SWITCHING POWER TRANSISTOR RT61 DEFROST THERMISTOR C61 SMOOTHING CAPACITOR LED LED RI62 DISCHARGE TEMP THERMISTOR C65 FAN MOTOR CAPACITOR LEV EXPANSION VALVE COIL RT64 FIN TEMP THERMISTOR 0861 0865 DIODE MODULE L61 REACTOR TB TERMINAL BLOCK F701 F801 FUSE T3 15AL250V MC COMPRESSOR Teu TRANSFORMER 1C700 POWER MODULE MF FAN MOTOR INNER FUSE X61 X63 X64 RELAY 1 802 POWER DEVICE PTC64 CIRCUIT PROTECTION 2194 REVERSING VALVE COIL 7 OBH648 TO INDOOR UNIT 7 REFRIGERANT SYSTEM DIAGRAM MUZ HJ25VA MUZ HJ35VA Unit mm Refrigerant pipe 29 52 4 way valve with heat insulator Muffler Discharge temperature thermistor RT62 Compressor Defrost thermisto RT61 Strainer 100 Flared connection j Refrigerant pipe 6 35 with heat insulator Capillary tube 3 0 x 1 4 x 260 R V coil Stop valve heating OFF with strainer cooling ON Refrigerant flow in cooling gt Refrigerant flow in heating MAX REFRIGERANT PIPING LENGTH and MAX HEIGHT DIFFERENCE Refrigerant piping m Piping size O D mm
5. Rated frequency Min Max Heating 3 15 0 9 3 5 3 6 1 1 4 1 Breaker Capacity 1 040 Cooling W 730 Power input 1 Total Heating 870 995 Running current 1 Cooling 3 7 4 9 Total Heating 4 2 4 8 Cooling 85 Power factor 1 Total 92 Electrical data Heating 90 90 Starting current 1 Total A 4 2 4 9 Coefficient of performance Cooling 3 42 3 03 COP 1 Total Heating 3 62 3 62 Model KNBO65FUJHC KNBO73FUVHC Output W 500 550 Compressor Cooling 3 3 Current 1 4 4 Heating 3 8 4 4 Refrigeration oil Model L 0 32 NEO22 Model RA6V21 BD Fan motor Current 1 0 23 Dimensions W x H x D 699 x 538 x 249 Weight Dehumidification Cooling Air flow 1 Cooli Sound level 1 29109 Heating Fan speed Special remarks Fan speed regulator Refrigerant filling capacity R410A NOTE Test conditions are based on ISO 5151 Cooling Indoor Dry bulb temperature 27 C Wet bulb temperature 1 Outdoor Dry bulb temperature 35 C Heating Indoor Dry bulb temperature 20 C Outdoor Dry bulb temperature 7 C Wet bulb temperature Refrigerant piping length one way 5 m 1 Measured under rated operating frequency Specifications and rated conditions of main electric parts Model item MUZ HJ25VA 9 C 6 C MUZ HJ
6. Dose LED on the inverter between DB61 and DB61 on 2 Replace the inverter the inverter P C board Yes up or flash Refer ANS board Refer to 11 6 1 No Yes Check the electric parts in main circuit If light up OK If flash refer to 11 3 Check of LEV Expansion valve Turn ON the power supply lt Preparation of the remote controller gt 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 displayed Then release the buttons Press OPERATE STOP ON OFF button of the remote controller the set temperature is displayed with the remote controller headed towards the indoor unit 1 Y Expansion valve operates in full opening direction Y x1 Regardless of normal or abnormal condition a short Do you hear the expansion valve click is emitted once the signal is received click sess m Do you feel the expansion valve vibrate Yes on touching it pe Is LEV coil properly fixed to Properly fix the LEV coil to the expansion valve the expansion valve No Yes Measure each voltage between connector pins of CN724 on the inverter P C board 1 Pi
7. Heating 7 Total input W Indoor air wet and dry bulb temperature difference on the left side of the following chart shows the difference between the indoor intake air wet and dry bulb temperature and the indoor outlet air wet and dry bulb temperature for your reference at service 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 must be attached to the position where air speed is high 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 Check that the air filter is cleaned Open windows and doors of room Press the EMERGENCY OPERATION switch once twice to start the EMERGENCY COOL HEAT MODE When system stabilizes after more than 15 minutes measure temperature and take an average temperature 10 minutes later measure temperature again and check that the temperature does not change N NOOR INDOOR UNIT OUTDOOR UNIT HHE 4 Wet and dry bulb Wet and dry bulb thermometers thermometers FRONT VIE
8. m E aE UE IE E E Jt 3 m f E gt 3 es x is r uesl o F J N R d R o I 1 r l n ti E K 40 I 3 K 40 E a RE 1 TNC40 I ds a sis d ks j NV z h 2 F F 4 N 2 I gt F 2 I E 9 30 INJ i 9 30 a I I d a I E F z EE i z N F I 1 lt i F F 1 20 APPROXIMATE 1 m 20 APPROXIMATE F I F 3 gt THRESHOLD OF 1 gt THRESHOLD OF LN E r 1 lt HEARING FOR JNC 20 amp HEARING FOR 5 INC 20 CONTINUOUS 1 o CONTINUOUS r jol LNOISE 3 yoh F F 1 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1000 2000 4000 8000 BAND CENTER FREQUENCIES Hz BAND CENTER FREQUENCIES Hz Test conditions Cooling Dry bulb temperature 35 C Heating Dry bulb temperature 7 C Wet bulb temperature 6 C OUTDOOR UNIT im MICROPHONE OBH648 R 9 OUTLINES AND DIMENSIONS MUZ HJ25VA MUZ HJ35VA Air in Drain hole 233 z n SE P Sc SS Air in LEVI N s z 232 AM out 2 10 3 X 19 3 Oval hol 349 5 ji A e 157 7 Hi TIT Liquid refrigerant pipe joint Refrigerant pipe flared 26 35 Gas refrigerant pipe joint Refrigerant pipe flared 99
9. 1 1 2 er 26 5 ay 1745 19 34 1 dew 15 8 17 64 5 10 qos mb 5 143 4 158 Me sta 127 141 2 os det iti 3 2 11 14 12 34 07 Er 9 5 10 5 o6 gt gt 10 5 0 5 10 15 10 5 5 10 15 4 5 45 Outdoor intake air Wet bulb temperature Outdoor intake air Wet bulb temperature C gt 5 gt 5 ae 88 3 zs NOTE The above broken lines are for the heating operation without any frost and Ne Se defrost operation 55 Es OBH648 M 8 2 CAPACITY AND INPUT CORRECTION BY OPERATIONAL FREQUENCY OF COMPRESSOR MUZ HJ25VA Correction of Cooling capacity Correction of Cooling total input M Correction of Heating capacity i Correction of Heating total input o E 5 o S 5 5 c 1 0 81 0 S 9 5 9 S E 5 8 8 gt 0 5 0 5 gt 5 o 5 5 S 5 3 2 m o 0 50 100 150 Hz 0 50 100 150 Hz 150 Hz 0 50 100 150 Hz The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor MUZ HJ35VA Correction of Cooling capacity i Correction of Cooling total input 18 Correction of Heating capacity of Heating total input N 9 p o S 6 c 1 0 8 1 0 o sq 5 5 5 S 5 gt 5 0 5 gt 8 0 5 o 5 S 5 H 0 50 100 150 Hz 0 50 100 150 Hz O 50 100 1
10. 10 SERVICE FUNCTIONS MUZ HJ25VA MUZ HJ35VA 10 1 10 2 CHANGE IN DEFROST SETTING lt JS gt When the JS wire of the inverter P C board is cut soldered the defrost finish temperature is changed Refer to 11 6 1 Jumper wire Defrost finish temperature C Soldered 8 Initial setting JS N one 11 Cut 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 outside tempera ture The pre heat control prevents this interference The pre heat control turns ON when outside temperature is 20 C or below When pre heat control is turned ON compressor is energized About 50 W lt JK gt When the JK wire of the inverter P C board is cut pre heat control is activated Refer to 11 6 1 NOTE When the inverter P C board is replaced check the Jumper wires and cut solder them if necessary 11 TROUBLESHOOTING MUZ HJ25VA MUZ HJ35VA 11 1 1 CAUTIONS ON TROUBLESHOOTING Before troubleshooting check the following 1 Check the power supply voltage 2 Check the indoor outdoor connecting wire for miswiring Take care of the following during servicing 1 Before servicing the air conditioner be sure to turn OFF the main unit first with the remote controller and then after confirming the horizontal vane is closed turn OFF the breaker and or disconnect the power plug 2 Be sure
11. 52 OBH648 Unit mm 6 WIRING DIAGRAM MUZ HJ25VA 1801 01 INVERTER P BOARD TB 5 N64 Tk 1 4 5 NOTES es eR Cere YQ pak V VR ra Va ae ew See RED 1 About the indoor side electric 4 ale 5 T wiring refer to the indoor unit electric wiring diagram RT6l RT62 for servicing 2 Use copper conductors only For field wiring LEV SYMBOL NAME NAME NAME CN61 CONNECTOR SWITCHING POWER TRANSISTOR DEFROST THERMISTOR C61 SMOOTHING CAPACITOR LED DISCHARGE TEMP THERMISTOR C65 FAN MOTOR CAPACITOR EXPANSION VALVE COIL FIN TEMP THERMISTOR 0861 DB65 DIODE MODULE REACTOR TERMINAL BLOCK F701 F801 FUSE T3 15AL250V COMPRESSOR TRANSFORMER 1C700 POWER MODULE FAN MOTOR INNER FUSE RELAY 1 802 POWER DEVICE PTC64 CIRCUIT PROTECTION 2154 REVERSING VALVE COIL MF 2154 N771 S CNT 1 3 X63 t F801 E L ee ee IRE fr a INVERTER BOARD MT WH LOU y LDV MCW 4 OA CN61 16700 I 22 53 NOTES O T TETT
12. 876 945 21 915 985 26 965 1035 INDOOR DB C NOTE Q Total capacity kW INPUT Total power input W DB Dry bulb temperature WB Wet bulb temperature OBH648 9 ACTUATOR CONTROL MUZ HJ25VA MUZ HJ35VA 9 1 OUTDOOR FAN MOTOR CONTROL The fan motor turns ON OFF 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 5 seconds 15 seconds ON lt gt Compressor OFF ON 9 2 R V COIL CONTROL Heating oe AE Nay Ee oe these ee OFF Cooling asuy e ee x qox Q ee Ee ats ON Dry serui reme ON NOTE The 4 way valve reverses for 5 seconds right before start up of the compressor COOL HEAT 5 seconds 5 seconds t ON TEN ompressor OFF RVcoi ON OFF i i i Outdoor fan ON i OFF I motor 9 3 RELATION BETWEEN MAIN SENSOR AND ACTUATOR Actuator Sensor Purpose Outdoor fan Indoor fan Compressor motor motor Discharge temperature thermistor Protection Cooling Coil frost prevention Indoor coil temperature thermistor Heating High pressure protection Defrost thermistor Heating Defrosting Cooling High pressure protection Fin temperature thermistor Protection OBH648 k
13. check inverter compressor Inverter P C board MUZ HJ25 35 LED Flashing 11 4 TROUBLE CRITERION OF MAIN PARTS MUZ HJ25VA MUZ HJ35VA Part name Check method and criterion Figure Measure the resistance with a tester Defrost thermistor RT61 Refer to 11 6 Test point diagram and voltage 1 Inverter P C board for the chart of thermistor Measure the resistance with a tester Discharge temperature Before measurement hold the thermistor with your hands to warm it thermistor RT62 up Fin temperature thermistor RT64 Refer to 11 6 Test point diagram and voltage 1 Inverter P C board for the chart of thermistor Measure the resistance between the terminals with a tester Part temperature 10 40 C WHT BLK Normal U V MUZ HJ25VA MUZ HJ35VA U W V W 2 01 2860 1 20 1 720 Measure the resistance between the terminals with a tester Outdoor fan motor MF Part temperature 10 40 C INNER FUSE a RA6V21 AB orma 1522 C CUT OFF FALL RA6V21 AB RA6V21 BB BD FUSE RA6V21 BB WHT BLK 305 374 Q 222 2720 126 2 CUT OFF BLK RED 247 304 Q 245 3000 uie REDE Measure the resistance between the terminals with a tester Part temperature 10 C 40 C R V coil 2154 Normal 1 19 1 78 kQ Measure the resistance using a tester Part temperature 10 40 C
14. 0 minutes Compressor starts Abnormal IC700 failure Compressor winding short Abnormal Compressor lock out Starting defect Abnormal Poor contact Outdoor PC board defect Disconnected connector Abnormal Refrigerant circuit defect Closed valve E Check of compressor start failure Make sure that O is normal Electrical circuit check Contact of the compressor connector Including CN61 Output voltage of inverter P C board and balance of them See 11 5 Direct current voltage between DB61 and on the inverter board Voltage between outdoor terminal block S1 S2 Does the compressor run for 10 seconds or Check the refrigerant circuit more after it starts Yes Check the stop valve After the compressor is heated with does the compressor start x1 No Replace the compressor Yes x1 Compressor start failure Activate pre heat control A En yedi with Refer to 10 2 PRE HEAT CONTROL SETTING p adrier for about 20 minutes Do not recover refrigerant gas while heating Heating part Check of outdoor thermistors Disconnect the connector of thermistor in the inverter P C board see below table and measure the resistance of thermistor Y Is the thermistor normal Refer to 11 6 1 No 7 Replace the thermistor except RT64 When RT64 Ye
15. 2 The terminal with this connector has the locking mechanism Hold the sleeve and pull out the terminal slowly Connector NOTE Turn OFF power supply before disassembly PHOTOS 1 Removing the cabinet and the panels 1 Remove the screw fixing the service panel 2 Pull down the service panel and remove it 3 Disconnect the power supply and indoor outdoor con necting wire 4 Remove the screws fixing the top panel 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 Photo 4 9 Remove the screws fixing the back panel 10 Remove the back panel Photo Z Screws of the top panel Direction to remove Screws of the service panel e Hooks Screw of the cabinet OBH648 S Photo 1 Screws of the top panel s 1 y 1 Screws of the cabinet Screws of the back panel OPERATING PROCEDURE PHOTOS 2 Removing the inverter assembly inverter P C Photo 4 board Screw of the Screws of the terminal 1 Remove the cabinet and the panels Refer to 1 heat sink and the block support and the 2 Disconnect the lead wire to the reactor and the follow separator back panel ing connectors lt Inverter P C board gt CN721 R V coil CN771 Fan motor CN641 Defrost thermistor and discharge temperature thermistor CN724 LEV 3 Remove the compress
16. 2 unit failure mode recall function Refer to 11 2 2 Yes Judgment of indoor outdoor abnormality V Blink Before blinking does the upper lamp of OPERATION INDICA TOR lamp stay ON for 3 seconds Stays ON for 3 seconds without beep Yes The outdoor unit is abnormal The indoor unit is abnormal The outdoor unit is abnormal Check the blinking pattern and identify the abnormal point with the indoor unit Check the blinking pattern and confirm the abnormal point with the failure mode table Refer to indoor unit service manual outdoor unit failure mode table Refer to 11 2 3 Make sure to check at least two consecutive blinking cycles 2 Make sure to check at least two consecutive blinking cycles 3 Releasing the failure mode recall function P 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 Y Repair the failure parts Deleting the memorized abnormal condition After repairing the unit recall the failure mode again according to Setting up the failure mode recall function mentioned above Press OPERATE STOP ON OFF button of the remote controller the set temperature is displayed with the remote controller headed towards the indoor unit Press EMERGENCY OPERATION switch so that the memorized abnormal condition is d
17. 35VA Smoothing capacitor C61 800 u 420 Diode module DB65 DB61 15A600 V 10 A600 V Fuse F701 F801 T3 15AL250V Power module 1 700 8 A600 V 10 A600 V Expansion valve coil LEV 12 VDC Reactor L61 18 mH Switching power transistor 1 821 30 600 V 30 Terminal block T 3P X61 3A 250V Relay X63 3A 250 V X64 20A250V Circuit protection PTC64 3 R V coil 2154 OBH648 i 220 240 VAC 4 NOISE CRITERIA CURVES MUZ HJ25VA MUZ HJ35VA FUNCTION SPL dB A LINE FUNCTION SPL dB A LINE COOLING 50 oe COOLING 50 9 HEATING 50 o HEATING 50 90 T 90 I r I 3 3 c i 3 1 1 x 7 1 1 lt 1 lt E Es 3 Ed m E F F m t 1 r o I 1 g 80 g 80 1 E F T o r 1 s L ft L i N L li y 3 e L F a L i S 70 70 1 TE 1 kd E t m F pre m F gt 960 J lt 60 i F m E T
18. 5 qu U gly 8B o LE PR e DUM TOI SOS K Eu Bu w o e w QUON NE 757 iui erue T B ich E N 324 wxium ff i go Li SONU 0 oo F L XE BTE 388 d B os Po A SM qn ANO BEI m 660000 N shy id A d j Front side of unit Fin temperature thermistor RT64 CN642 Defrost thermistor RT61 0 Resistance 0 Temperature C OBH648 10 20 Discharge temperature A thermistor RT62 Defrost thermistor RT61 CN641 CN641 32 30 40 50 lla 80 9 T 100 110 120 Temperature C Jumper wire for changing LEV connector defrost setting JS CN724 Jumper wire for pre heat control setting JK T Fin temperature thermistor RT64 0 0 10 20 30 40 50 Tum 70 8 80 Temperature C 12 DISASSEMBLY INSTRUCTIONS lt Terminal with locking mechanism Detaching points gt The terminal which has the locking mechanism can be detached as shown below There are two types refer to 1 and 2 of the terminal with locking mechanism The terminal without locking mechanism can be detached by pulling it out Check the shape of the terminal before detaching 1 Slide the sleeve and check if there is a locking lever or not Slide the sleeve GPull the terminal while pushing the locking lever 12 1 MUZ HJ25VA MUZ HJ35VA OPERATING PROCEDURE
19. 5 seconds OFF Discharge temperature Temperature of discharge temperature thermistor exceeds 116 C compressor stops Compressor can restart if discharge temperature thermistor reads 100 C or less 3 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 5 seconds OFF Temperature of fin temperature thermistor on the inverter P C board exceeds 80 C or temperature of P C board temperature thermistor 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 motor 9 time flash 2 5 seconds OFF Nonvolatile memory data 5 time flash 2 5 seconds OFF Nonvolatile memory data cannot be read properly Replace the inverter P C board Power module 6 time flash 2 5 seconds OFF The interface short circuit occurs in the output of the power module IC700 The compressor winding shorts circuit Refer to 11 5 How to check inverter compressor 10 time flash 2 5 seconds OFF Discharge temperature Temperature of dis
20. 50 Hz 0 50 100 150 Hz The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor 8 3 HOW TO OPERATE FIXED FREQUENCY OPERATION Test run operation Press EMERGENCY OPERATION switch to start COOL or HEAT mode COOL Press once HEAT Press twice Test run operation starts and continues to operate for 30 minutes Compressor operates at rated frequency in COOL mode or 58 Hz in HEAT mode Indoor fan operates at High speed After 30 minutes test run operation finishes and EMERGENCY OPERATION starts operation frequency of compressor varies To cancel test run operation EMERGENCY OPERATION press EMERGENCY OPERATION switch or any button on remote controller O gt O N OBH648 E 8 4 OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT COOL operation Dry bulb temperature C Relative humidity 20 50 Both indoor and outdoor unit are under the same tempera ture humidity condition 25 60 Operation TEST RUN OPERATION Refer to 8 3 Outdoor low pressure MUZ HJ25VA MUZ HJ35VA kgf cm Gauge MPa Gauge kgf cm Gauge MPa Gauge 9 0 9 8 0 8 1 07 707 eL 0 6 4L 0 4 3L 0 3 15 1820 25 30 32 35 C 15 1820 25 30 32 35 50 60 70 50 60 70 Ambient temperature C Ambient temperature C Ambient humidity Ambient humidity NOTE The unit o
21. BH648 New publication effective Dec 2012 Made in Japan Specifications are subject to change without notice
22. Changes for the Better MITSUBISHI ELECTRIC SPLIT TYPE AIR CONDITIONERS OUTDOOR UNIT SERVICE MANUAL 648 R410A Models MUZ HJ25VA MUZ HJ35VA Indoor unit service manual MSZ HJ VA Series OBH647 CONTENTS MUZ HJ25VA MUZ HJ35VA 1 TECHNICAL CHANGES S r state 3 2 PART NAMES AND FUNCTIONS 3 3 SPECIFICATION ST T 4 4 NOISE CRITERIA CURVES Dondaenannonnnonoaonenenoeoneno 5 5 OUTLINES AND DIMENSIONS 6 6 WIRING DIAGRAM Donnepanmnennnonnmneneonmnennenemenennonanono 7 7 REFRIGERANT SYSTEM DIAGRAM 8 8 PERFORMANCE CURVES x wap awana sss saa zas ATT 9 9 ACTUATOR CONTROL TT I LITT 18 10 SERVICE FUNCTIONS S 19 11 TROUBLESHOOTING a 19 12 DISASSEMBLY INSTRUCTIONS 33 PARTS CATALOG OBB648 NOTE RoHS compliant products have lt G gt mark on the spec name plate C 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 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 breakdo
23. Is there 230 VAC between CN7210 Replace the inverter EMERGENCY OPERATION switch after the power supply is turned ON twice HEAT mode No Replace the 4 way valve D Check of outdoor fan motor t the resistance of fan motor Refer to 11 4 Is the resistance of Replace the outdoor fan motor normal No fan motor Yes Disconnect the connector CN771 on the inverter P C board Disconnect the connector CN61 between compressor and power transistor module Turn ON the power supply and press the EMERGENCY OPERATION switch After 3 minutes is Does the upper lamp ot there voltage 230 VAC OPERATION bet CN771 and Replace the inverter INDICATOR lamp on z a eripi Bo P C board the indoor unit light up Yes Replace the outdoor fan motor OBH648 J Check of power supply 250 370 VDC Disconnect the connector CN61 between compressor and power module Turn ON power supply and press Rectify indoor outdoor EMERGENCY OPERATION switch connecting wire Inverter P C board Solder side Yes Does the upper lamp of OPERATION Is there voltage 230 Replace the indoor INDICATOR lamp on the indoor unit between the indoor terminal No electronic control P C light up block S1 and S2 board Is there 250 370
24. W BACK VIEW OBH648 8 1 CAPACITY AND INPUT CURVES Indoor air Wet bulb temperature Indoor air Wet bulb temperature Indoor air Wet bulb temperature difference C sta 0 2 0 2 difference C difference C m MUZ HJ25VA at Rated frequency 8 0 7 4 6 8 6 2 5 6 5 1 MUZ HJ35VA at Rated frequency Capacity correction factor o N W U o Cooling capacity 18 20 25 30 35 40 4546 Outdoor intake air Dry bulb temperature C Total input cooling 6 1 68 1 3 1 2 5 6 62 8 1 26 24 28 5 1 5 6 6 1 1 18 46 5 1 8 1 0 4 1 4 5 0 9 oC 8 semperature 3 6 40 0 8 wetpu intake 18 20 25 30 35 40 4546 55 lt 5 3 3 Outdoor intake air Dry bulb temperature C Se Sc Heating capacit i i 20 6 22 9 E g capacity R Total input heating 20 19 0 21
25. act in the anten Yes Replace or repair the coaxial cable na wiring Is the indoor outdoor connecting wire Extend the distance between the indoor outdoor of the air conditioner and the wiring of connecting wire of the air conditioner and the wir the antennas close Yes ing of the antennas Even if all of the above conditions are fulfilled the electromagnetic noise may enter depending on the electric field strength r the installation condition combination of specific conditions such as antennas or wiring Check the following before asking for service T 2 3 4 OBH Devices affected by the electromagnetic noise TV sets radios FM AM broadcast shortwave Channel frequency broadcast station affected by the electromagnetic noise Channel frequency broadcast station unaffected by the electromagnetic noise Layout of indoor outdoor unit of the air conditioner indoor outdoor wiring earth wire antennas wiring from antennas receiver Electric field intensity of the broadcast station affected by the electromagnetic noise Presence or absence of amplifier such as booster Operation condition of air conditioner when the electromagnetic noise enters in 1 Turn OFF the power supply once and then turn ON the power supply In this situation check for the electromagnetic noise 2 Within 3 minutes after turning ON the power supply press OPERATE STOP ON OFF button on the remote controller for
26. ch does not recur 1 Flow chart of failure mode recall function for the indoor outdoor unit Operational procedure The cause of abnormality cannot be found because the abnormality does not recur Setting up the failure mode recall function j Turn ON the power supply lt Preparation of the remote controller gt 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 displayed Then release the but tons MITSUBISHI ELECTRIC Y Press OPERATE STOP ON OFF button of the remote controller the set temperature is displayed with the remote controller headed towards the indoor unit x1 x1 Regardless of normal or abnormal condition a short Y beep is emitted once the signal is received Does the upper lamp of OPERATION INDICATOR lamp on th Indoor unit is normal indoor unit blink at the interval of 0 5 seconds But the outdoor unit might be abnormal because there are some abnor Blinks Either indoor or outdoor unit is abnormal Beep is No malities that can t be recalled with this way emitted at the same timing as the blinking of the upper OFF Confirm if outdoor unit is abnormal according to the detailed outdoor lamp of OPERATION INDICATOR lamp
27. charge temperature thermistor has been 50 C or less for 20 minutes Refer to 11 5 Check of LEV Check refrigerant circuit and refrigerant amount 11 time flash 2 5 seconds OFF DC voltage 8 time flash 2 5 seconds OFF DC voltage of inverter cannot be detected normally Each phase current of compressor 9 time flash 2 5 seconds OFF Each phase current of compressor cannot be detected normally Refer to 11 5 6 How to check inverter compressor 14 time flash 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 4 way valve Replace inverter P C board NOTE Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE 11 3 OBH648 22 11 3 TROUBLESHOOTING CHECK TABLE Symptom LED indication Abnormal point Condition Condition Remedy Outdoor unit does not op erate 1 time flash every 2 5 seconds Outdoor power sys tem Overcurrent protection cut out operates 3 consecutive times within 1 minute after the compressor gets started or failure of restart of compressor has repeated 24 times Reconnect connector of compres Sor Re
28. ctronic control P C board 3 3 3 Be sure to release the failure mode recall 30 No 3 2 Be careful of 140 ing it may lead to damage to the P C board Is there any problem in the indoor outdoor connecting wire such as the damage of the wire intermediate connection poor contact with the terminal block No the indoor outdoor con Yes necting wire Replace the indoor inverter board 2 VDC 280 VDC residual charge in the capacitor on the main inverter circuit Replace the indoor inverter P C board 2 function after checking Elect romagnetic noise enters into TV sets or radios lt Is the unit earthed NE Earth the unit Yes Is the distance between the antennas and the indoor unit within 3 m or is the distance between the antennas and the Yes outdoor unit within 3 m No Extend the distance between the antennas and the indoor unit and or the antennas and the outdoor unit Is the distance between the TV sets or radios and the indoor unit within 1 m or is the distance between the TV sets Yes radios and the outdoor unit within 3 m No Extend the distance between the TV sets and or radios and the indoor unit or the TV sets or radios and the outdoor unit Are the antennas damaged Is the coaxial cable damaged Replace or repair the antenna Is there any poor cont
29. ec tion Large current flows into power module When overcurrent protection occurs within 10 seconds after compressor starts compressor restarts after 15 seconds Reconnect connector of compressor Refer to 11 5 How to check in verter compressor Check stop valve 3 time flash 2 5 seconds OFF Discharge tempera ture overheat pro tection Temperature of discharge temperature thermistor exceeds 116 C compressor stops Compressor can restart if discharge temperature thermistor reads 100 C or less 3 minutes later eCheck refrigerant circuit and refrig erant amount Refer to 11 5 Check of LEV 4 time flash 2 5 seconds OFF Fin temperature IP C board tem perature thermistor overheat protection Temperature of fin 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 D Check of outdoor fan motor 5 time flash 2 5 seconds OFF High pressure pro tection Indoor coil thermistor exceeds 70 C in HEAT mode Defrost thermistor exceeds 70 C in COOL mode Check refrigerant circuit and refrig erant amount Check stop valve 8 time flash 2 5 seconds OFF Compressor syn chronous abnormal ity The waveform of compressor current is distorted Reconnect connector of compressor Refer to 11 5 Ho
30. econd i Setting up the failure mode recall function 1 lt gt I ON 30 second OFF Aim the remote controller at the indoor unit and press OPERATE STOP ON OFF button The relay 52 will be turned on and the outdoor unit will be energized 3 4 Make sure that the wiring is correct If the pro cedure is performed without correcting miswir A Turn OFF inverter controlled lighting equipment Turn OFF the power supply and then turn ON again Press the emergency operation switch Reinstall ei ther the unit or the light away from each other Attach a filter on remote control receiving section of the indoor unit After the relay 52C is turned on 3 minutes later is miswiring or the serial signal error indicated OBH648 Y Is the rated supply voltage applied between the S1 and S2 on the outdoor terminal block Check of supply voltage Y Yes Is there approximately 250 VDC 370 VDC between DB61 and DB61 on the indoor inverter P C board Voltage check of the inverter P C board Yes Does the LED on the inverter P C board 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 is normal or not Yes Replace the indoor ele
31. eleted Release the failure mode recall function according to Releasing the failure mode recall function mentioned above NOTE 1 Make sure to release the failure mode recall function after it is set up otherwise the unit cannot operate properly 2 If the abnormal condition is not deleted from the memory the last abnormal condition is kept memorized X2 Blinking pattern when the indoor unit is abnormal Blinking at 0 5 Blinking at 0 5 2 5 second OFF second interval 2 5 second OFF second interval lt gt lt gt lt gt lt P gt aa DSL ir OFF 4 te x 4 te lt lt lt Beeps gt lt Beeps gt Beeps Repeated cycle Repeated cycle Repeated cycle 3 Blinking pattern when the outdoor unit is abnormal ae Blinking at 0 5 Blinking at 0 5 2 5 second OFF 3 second ON second interval 2 5 second OFF 3 second ON second interval 4 gt lt gt lt gt lt gt lt gt gt VT Tr F t OFF PL lt gt aF 0 4 No beep Beeps gt lt Repeated cycle Repeated cycle OBH648 oe 2 Flow chart of the detailed outdoor unit failure mode recall function Operational procedure The outdoor unit might be abnormal Check if outdoor unit is abnormal according to the following procedures Y Make sure that the remote controller is set to the failure mode recall function Y With the remote cont
32. f 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 cm Gauge Outdoor unit current MUZ HJ25VA MUZ HJ35VA 5 6 lt lt 5 5 o o S S 3 3 5 3 5 4 o o 2 3 15 1820 25 30 32 35 C 15 1820 25 30 32 35 50 60 70 50 60 70 Ambient temperature C Ambient temperature C Ambient humidity Ambient humidity HEAT operation Condition Indoor Outdoor Dry bulb temperature C 20 0 7 15 Wet bulb temperature 14 5 6 12 Operation Test run operation refer to 8 3 Outdoor unit current MUZ HJ25VA MUZ HJ35VA 3 0 3 0 lt lt 2 5 2 5 820 8 2 0 6 6 k a u 5 10 15 20 25 5 10 15 20 25 Ambient temperature C Ambient temperature C OBH648 PERFORMANCE DATA COOL operation at Rated frequency MUZ HJ25VA CAPACITY 2 5 kW SHF 0 89 INPUT 730 W OUTDOOR DB C INDOOR INDOOR DB C WB C NOTE Q Total capacity kW SHF Sensible heat factor DB Dry bulb temperature SHC Sensible heat capacity kW INPUT Total power input W WB Wet bulb temperature OBH648 PERFORMANCE DATA COOL operation at Rated frequency MUZ HJ25VA CAPACITY 2 5 kW SHF 0 89 INPUT 730 W OUTDOOR DB C 40 INDOOR INDOOR DB C WB C
33. fer to 11 5 6 How to check in verter compressor Check stop valve Outdoor thermistors Discharge temperature thermistor fin temperature thermistor defrost thermistor P C board temperature thermistor or out door heat exchanger temperature thermistor shorts or opens during compressor running Refer to 11 5 Check of outdoor thermistors Outdoor control sys tem Nonvolatile memory data cannot be read properly The upper lamp of OPERATION INDICATOR lamp of the in door unit lights up or flashes 7 time Replace inverter P C board 6 time flash 2 5 seconds OFF Serial signal The communication fails between the indoor and outdoor unit for 3 minutes Refer to 11 5 D How to check miswiring and serial signal error 11 time flash 2 5 seconds OFF Stop valve Closed valve Closed valve is detected by compressor current Check stop valve 14 time flash 2 5 seconds OFF Outdoor unit Other abnormality Outdoor unit is defective Refer to 11 2 2 Flow chart of the detailed outdoor unit failure mode recall function 16 time flash 2 5 seconds OFF 4 way valve Pipe temperature The 4 way valve does not work properly The indoor coil thermistor detects an abnormal temperature Refer to 11 5 6 Check of R V coil Replace inverter P C board Outdoor unit stops and restarts 3 minutes later is repeated 2 time flash 2 5 seconds OFF Overcurrent prot
34. lashes 9 times Refer to 11 6 1 OBH648 Check of compressor Refer to 11 5 0 Check of compressor winding No Is the compressor normal Refer to 11 5 Check of compressor operation time Does the compressor operate continuously Yes D Check of compressor winding Replace the compressor Refer to 11 5 Check of compressor start failure e Disconnect the connector CN61 between the compressor and power module and measure the resistance between the com pressor terminals Measurement point At 3 points BLK WHT BLK RED WHT RED lt lt Judgement gt gt Refer to 11 4 O Q vr Abnormal short Infinite Q Abnormal open NOTE sure to zero the ohmmeter before measurement Check of compressor operation time e Connect the compressor and activate the inverter Then measure the time until the inverter stops due to over current lt lt Operation method gt gt Start heating or cooling operation by pressing EMERGENCY OPERATION switch on the indoor unit TEST RUN OPERATION Refer to 8 3 lt lt Measurement gt gt Measure the time from the start of compressor to the stop of compressor due to overcurrent OBH648 26 Measure the resistance between the lead wires at 3 points lt lt Judgement gt gt 0 second 1 second 2 seconds 10 seconds 1
35. mmunication receiving error Although the inverter P C board sends signal 0 signal 1 has been received 30 consecutive times Refer to 11 5 O How to check miswiring and serial signal error 2 time flash 2 5 seconds OFF Outdoor power system Overcurrent protection cut out operates 3 consecutive times within 1 minute after the compressor gets started Reconnect connectors Refer to 11 5 How to check inverter compressor Check stop valve 3 time flash 2 5 seconds OFF Discharge temperature thermistor Defrost thermistor 1 time flash every 2 5 seconds Fin temperature thermistor 3 time flash 2 5 seconds OFF P C board temperature thermistor 4 time flash 2 5 seconds OFF Thermistor shorts or opens during compressor running Refer to 11 5 Check of outdoor thermistors Defective outdoor thermistors can be identified by checking the blinking pattern of LED 4 time flash 2 5 seconds OFF Overcurrent 11 time flash 2 5 seconds OFF Large current flows into power module Reconnect compressor connector Refer to 11 5 How to check inverter compressor Check stop valve Compressor synchronous abnormality Compressor start up failure protection 12 time flash 2 5 seconds OFF Waveform of compressor current is distorted Reconnect compressor connector Refer to 11 5 How to check inverter compressor 5 time flash 2
36. n Pin Does the resistance of LEV 2 Pin Pin coil have the characteristics gg gt 3 Pin Pin inverter Refer to 11 4 4 Pin No Is there about 3 5 between each NOTE Measure the voltage by an analog Replace the LEV coil tester ves Replace the expansion valve NOTE After check of LEV do the undermentioned operations 1 Turn OFF the power supply and turn ON it again 2 Press RESET button on the remote controller OBH648 How to check miswiring and serial signal error No Check the power supply No Y Y Yes Turn OFF the power supply gt Is there rated voltage in the power supply 1 Turn ON the power supply 2 Press the emergency operation switch Has the relay 52C been turned on 3 minuets later The relay will be turned on in 3 to 7 seconds by short circuiting the timer short mode point Refer to 10 7 Initializing the determination of the power receiving system The microprocessor may have mistaken the unit as a model receiving power from the outdoor unit Follow the procedure below to start the determination of the power receiv ing system all over again 1 Hold down the emergency operation switch for 30 seconds Do not release the switch even though a buzzer beeps once in about 5 seconds Kee
37. or 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 Photo 5 Inverter assembly 1 Remove the cabinet and the panels Refer to 1 Heat sink P C board Screw of the 2 Disconnect the following connectors Heat sink support support earth wire lt Inverter P C board gt CN721 R V coil 3 Remove the R V coil Screw of the P C board terminal block support OBH648 OPERATING PROCEDURE PHOTOS 4 Removing the discharge temperature thermistor and the defrost thermistor 1 Remove the cabinet and the panels Refer to 1 2 Disconnect the lead wire to the reactor and the follow ing connectors lt Inverter P C board gt CN641 Defrost thermistor and discharge temperature thermistor 3 Pull out the discharge temperature thermistor from its holder 4 Pull out the defrost 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 lt Inverter P C boa
38. or unit Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted Release the failure mode recall function according to Releasing the failure mode recall function men tioned above NOTE 1 Make sure to release the failure mode recall function after it is set up otherwise the unit cannot operate properly 2 If the abnormal condition is not deleted from the memory the last abnormal condition is kept memorized x 2 Blinking pattern when outdoor unit is abnormal P Blinking at 0 5 Blinking at 0 5 2 5 second OFF 3 second ON second interval 2 5 second OFF 3 second ON second interval lt 4 gt lt gt lt gt lt gt lt gt E hi l R i e e gt oo i PW i P i No beep Beeps pa No beep Repeated cycle f Repeated cycle Repeated cycle OBH648 3 Outdoor unit failure mode table The upper lamp of OPERATION INDICATOR lamp Indoor unit Abnormal point Failure mode protection LED indication Outdoor P C board Condition Indoor outdoor unit failure mode recall function Outdoor unit failure mode recall function OFF None Normal 1 time flash 2 5 seconds OFF Indoor outdoor communication receiving error Any signals from the inverter P C board cannot be received normally for 3 minutes Refer to 11 5 O How to check miswiring and serial signal error Indoor outdoor co
39. p holding down the switch until a buzzer beeps again for 1 second after 30 seconds Figure 1 Yes gt Has the miswiring or the serial error No been indicated Yes Indication of miswiring Indication of serial signal error OPERATION INDICATOR lamp Continuous blinks 2 Turn off the power supply Is there any miswiring poor 3 Wait for about 30 seconds contact or wire disconnec tth 4 Turn on the power supply tion of the indoor outdoor No 5 Press the emergency operation switch connecting wire 6 The relay 52C will be turned on in 3 min Yes utes lt Figure 1 Y Buzzer ON second OFF the power supply Make sure again that the indoor outdoor connecting wire is correctly connected With the indoor outdoor connecting wire connected short circuit OFF la gt between S2 and S3 on the outdoor terminal block 1 iBeeps Beeps 1 Beeps lt Preparation of the remote controller gt Saa 49 i While pressing both OPERATION SELECT button and Emergency 1 i TOO COOL button on the remote controller at the same tio itch I time press RESET button PRS i First release RESET button ON Hold down the other two buttons for another 3 seconds gt Make sure that the indicators on the LCD screen shown in MITSUBISHI ELECTRIC OFF the right figure all displayed Then release the buttons 5 s
40. power ON and check for the electromagnetic noise 3 After a short time 3 minutes later after turning ON the outdoor unit starts running During operation check for the electromagnetic noise 4 Press OPERATE STOP ON OFF button on the remote controller for power OFF when the outdoor unit stops but the indoor outdoor communication still runs on In this situation check for the electromagnetic noise 648 A 11 6 TEST POINT DIAGRAM AND VOLTAGE 1 Inverter P C board MUZ HJ25VA MUZ HJ35VA DB61 250 V 370 VDC Smoothing 230 capacitor C61 Output to drive outdoor V coil fan motor CN771 CN721 Fuse F701 T3 15AL250V Fuse F801 T3 15AL250V SS 3 n J Q 9 A e pO Z BOET B OS Mo T Ba s 55 e e NS Z r DD ELS e 4 9 o e wo Po gE l g Sy J osz vsre 94 99 I oT o of 9999 m o o Fo li t OD fam cu ise o o gL ud PM Output to E uo 16 T i ot drive Cum i g o 3 H 3 of BOE compressor 2 Oi m E Kd LDW 4 uy COPS ONE LL ss og o SOS P a 29 ps gt UTE 7 ox wal 230 VAC 2
41. rature thermistor protection When the outside temperature thermistor shorts or opens protective operation without that thermistor is performed Refer to 11 5 Check of outdoor thermistors Outdoor unit operates 7 time flash 2 5 seconds OFF Low discharge tem perature protection Temperature of discharge temperature thermistor has been 50 C or less for 20 minutes Refer to 11 5 Check of LEV Check refrigerant circuit and refrig erant amount 8 time flash 2 5 seconds OFF PAM protection PAM Pulse Ampli tude Modulation The overcurrent flows into 1 821 Switching power transistor or the bus bar voltage reaches 320 V or more PAM stops and restarts This is not malfunction 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 9 time flash 2 5 seconds OFF Inverter check mode The connector of compressor is disconnected inverter check mode starts NOTE 1 The location of LED is illustrated at the right figure Refer to 11 6 1 2 LED is lighted during normal operation The flashing frequenc Example When the 0 5 second ON y shows the number of times the LED blinks after every 2 5 second OFF lashing frequency is 2 2 5 second OFF OBH64 8 23 Check if the connector of the com pressor is correctly connected Refer to 11 5 How to
42. rd gt CN771 Fan motor 3 Remove the fan motor lead wire from where it is fas tened on the separator 4 Remove the propeller nut 5 Remove the propeller 6 Remove the screws fixing the fan motor 7 Remove the fan motor 6 Removing the compressor 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 terminal cover and the compressor lead wire 6 Recover gas from the refrigerant circuit NOTE Recover gas from the pipes until the pressure gauge shows 0 kg cm 0 MPa 7 Detach the brazed part of the suction and the dis charge pipe connected with the compressor 8 Remove the nuts of compressor legs 9 Remove the compressor 10 Detach the brazed part of pipes connected with the 4 way valve OBH648 35 Photo 6 Brazed part of the 4 way valve Photo 7 Screws of the reactor Photo 8 Propeller Brazed part of the 4 way valve Defrost thermistor Suction pipe brazed part A B7 W Discharge p Discharge temper brazed part ature thermistor Screws of the outdoor fan motor MITSUBISHI ELECTRIC CORPORATION HEAD OFFICE TOKYO BLDG 2 7 3 MARUNOUCHI CHIYODA KU TOKYO 100 8310 JAPAN Copyright 2012 MITSUBISHI ELECTRIC CORPORATION Distributed in Dec 2012 No O
43. roller headed towards the indoor unit press TOO 1 Regardless of normal or abnormal condition 2 short COOL or TOO WARM button to adjust the set temperature to 25 C X1 beeps are emitted as the signal is received Y Does the upper lamp of OPERATION INDICATOR lamp on the indoor unit blink at the interval of 0 5 seconds Blinks The outdoor unit is abnormal Beep is emitted No at the same timing as the blinking of the upper OFF lamp of OPERATION INDICATOR lamp X2 Yes Blinks The outdoor unit is abnormal Check 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 X2 The outdoor unit is normal Releasing the failure mode recall function Release the failure mode recall function by the following procedures i 2 OFF the power supply turn it ON again Release the failure mode recall function accord Press RESET button of the remote controller ing to the left mentioned procedure Y Repair the failure parts Deleting the memorized abnormal condition CD After repairing the unit recall the failure mode again according to Setting up the failure mode recall function 11 2 1 Press OPERATE STOP ON OFF button of the remote controller the set temperature is displayed with the remote controller headed towards the indo
44. s is abnormal replace board Y Reconnect the connector of thermistor Turn ON the power supply and press EMERGENCY OPERATION switch Does the unit operate for 10 minutes or more without showing thermistor abnormality No Replace the inverter P C board Yes OK Cause is poor contact Thermistor Connector Pin No Board Defrost Between CN641 pin 1 and pin 2 Discharge temperature Between CN641 pin 3andpin4 Inverter P C board Fin temperature Between CN642 pin 1 and pin 2 OBH648 xi H Check of R V coil First of all measure the resistance of R V coil to check if the coil is defective Refer to 11 4 x In case CN721 is not connected or R V coil is open voltage is generated between the terminal pins of the connector although any signal is not being transmitted to R V coil Check if CN721 is connected Unit operates COOL mode even if it is set to HEAT mode Disconnect connector CN61 between rss and the Is there 230 between CN7210 and inverter board 3 minutes No det ON after the power supply is turned ON switch once COOL mode Yes Replace the 4 way valve Replace the inverter P C board Unit operates HEAT mode even if it is set to COOL mode Disconnect connector CN61 between the compressor and the power module
45. to turn OFF the power supply before removing the front panel the cabinet the top panel and the electronic control P C board 3 When removing the electrical parts be careful to the residual voltage of smoothing 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 housing of the connector DO NOT pull the lead wires lt Incorrect gt lt Correct gt Lead wiring Housing point 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 check how many times the OPERATION INDICATOR lamp is flashing on and off before starting service work 2 Before servicing check that the connector and terminal are connected properly 3 When the electronic control P C board seems to be defective check the copper foil pattern for disconnection and the components for bursting and discoloration 4 Refer to 11 2 and 11 3 OBH648 11 2 FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once Even though LED indication listed on the troubleshooting check table 11 3 disappears the memorized failure details can be recalled This mode is very useful when the unit needs to be repaired for the abnormality whi
46. w to check in verter compressor 12 time flash 2 5 seconds OFF Each phase current of compressor Each phase current of compressor cannot be detected nor mally Refer to 11 5 How to check in verter compressor 13 time flash 2 5 seconds OFF DC voltage DC voltage of inverter cannot be detected normally Refer to 11 5 How to check in verter compressor Outdoor unit operates 1 time flash 2 5 seconds OFF Frequency drop by current protection When the input current exceeds 5 4 A HJ25 6 1 A HJ35 compressor frequency lowers 3 time flash 2 5 seconds OFF Frequency drop by high pressure pro tection Temperature of indoor coil thermistor exceeds 55 C in HEAT mode compressor frequency lowers Frequency drop by defrosting in COOL mode Indoor coil thermistor reads 8 C or less in COOL mode com pressor frequency lowers The unit is normal but check the following Check if indoor filters are clogged Check if refrigerant is short Check if indoor outdoor unit air circulation is short cycled 4 time flash 2 5 seconds OFF Frequency drop by discharge tempera ture protection Temperature of discharge temperature thermistor exceeds 111 C compressor frequency lowers Check refrigerant circuit and refrig erant amount Refer to 11 5 Check of LEV Refer to 11 5 Check of outdoor thermistors 5 time flash 2 5 seconds OFF Outside tempe
47. wn or accidents caused by failure to follow the instructions lt Preparation before the repair service gt Prepare the proper tools Prepare the proper protectors Provide adequate ventilation After stopping the operation of the air conditioner turn off the power supply breaker and remove the power plug Discharge the capacitor before the work involving the electric parts lt Precautions during the repair service gt 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 circuit needs to be done without turning off the power exercise great caution not to touch the live parts OBH648 i 1 TECHNICAL CHANGES MUZ HJ25VA m MUZ HJ35VA 1 1 New model 2 PART NAMES AND FUNCTIONS MUZ HJ25VA MUZ HJ35VA Airinlet Back and side Drain hose d F Air outlet V Drain outlet ACCESSORIES OBH648 i 3 SPECIFICATION Outdoor model MUZ HJ25VA MUZ HJ35VA Power supply Single phase 230 V 50 Hz Capacity Cooling 2 5 1 3 3 0 3 15 1 4 3 5

SERVICE MANUAL MUZ-HJ25VA - E1 MUZ

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