Hitachi RAC-25NH5 Service Manual Download Page 86

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TROUBLE SHOOTING

Model

RAK-25NH5 / RAC-25NH5
RAK-35NH5 / RAC-35NH5

PRECAUTIONS FOR CHECKING

Power source

–

CT Module

–

Compressor motor

System power module 2

Indoor unit
electric parts

Control
P.W.B.

DC35V

(0V)

MAIN P.W.B.

er module

1. Remember that the

0V line is biased to
155-170V in
reference to the
ground level.

2. Also note that it takes

about 10 minutes
until the voltage fall
after the power switch
is turned off.

DANGER

Across a – b (0V line)....................

Across a – ground..........................

Across b (0V line)– ground............

approx 260-360V

approx 155-170V

When using an
oscilloscope, never
ground it. Don't forget
that high voltages as
noted above may
apply to the
oscilloscope.

DANGER

Always keep your hands
and metallic things away
from the enclosure of the
oscilloscope.

DANGER!

Don’t install

the ground

line.

Oscilloscope

Outdoor unit P.W.B.

Summary of Contents for RAC-25NH5

Page 1: ...TION AND DIMENSIONAL DIAGRAM 29 MAIN PARTS COMPONENT 31 WIRING DIAGRAM 33 CIRCUIT DIAGRAM 35 PRINTED WIRING BOARD LOCATION DIAGRAM 41 BLOCK DIAGRAM 43 BASIC MODE 45 REFRIGERATING CYCLE DIAGRAM 59 AUTO SWING FUNCTION 61 DESCRIPTION OF MAIN CIRCUIT OPERATION 62 SERVICE CALL Q A 93 TROUBLE SHOOTING 96 PARTS LIST AND DIAGRAM 116 RAK 25NH5 RAC 25NH5 RAK 35NH5 RAC 35NH5 COOLING HEATING INDOOR UNIT OUTDO...

Page 2: ... be accurately calibrated in advance 7 In installing the unit having been repaired be careful to prevent the occurence of any accident such as electrical shock leak of current or bodily injury due to the drop of any part 8 To check the insulation of the unit measure the insulation resistance between the power cord plug and grounding terminal of the unit The insulation resistance should be 1M or mo...

Page 3: ...of parts Even rejected goods should be handled in the same way Fig 1 Conductive Container 2 When any part is handled uncovered in counting packing and the like the handling person must always use himself as a body earth Make yourself a body earth by passing one M ohm earth resistance through a ring or bracelet 3 Be careful not to touch the parts with your clothing when you hold a part even if a bo...

Page 4: ... the screwed part using a rag plate Soldering iron Grounding wire Fig 4 Grounding a soldering iron Use a high insulation mode 100V 10M or higher when ordinary iron is to be used 7 In checking circuits for maintenance inspection or some others be careful not to have the test probes of the measuring instrument shortcircuit a load circuit or the like Metal plate of aluminium stainless steel etc Stapl...

Page 5: ...casion that the cooling and heating operation does not start for 3 minutes it is not abnormal and this is the result of the operation of IC delay circuit This IC delay circuit ensures that there is no danger of blowing fuse or damaging parts even if operation is restarted accidentally 5 This room air conditioner should not be used at the cooling operation when the outside temperature is below 10 C...

Page 6: ...n of Piping about 1 6m about 0 9m The difference in height between the indoor and outdoor unit should be kept below 5m The connecting pipe no matter big or small should all be insulated with insulation pipe and then wrapped with vinyl tape The insulator will deteriorate if it is not wrapped with tape Connection Horizontally perpendicular to the unit There are 4 directions allowed namely horizontal...

Page 7: ...ARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL RAK 25NH5 RAK 35NH5 DC35V NO NO NO NO NO NO NO NO YES NO NO NO NO YES IC YES 40 W NO NO NO YES YES 3 0A G4A NO NO YES NO 450NR YES YES IC NO WITHOUT REFRIGERANT BECAUSE COUPLING IS FLARE TYPE UNIT PIPES MAX 20m REFRIGERANT CHARGING VOLUME Refrigerant 410A RAC 25NH5 RAC 35NH5 JU1012D 1150...

Page 8: ...anger of electric shock exists Do not install near location where there is flammable gas The outdoor unit may catch fire if flammable gas leaks around it Please ensure smooth flow of water when installing the drain hose CAUTION PRECAUTIONS DURING SHIFTING OR MAINTENANCE PRECAUTIONS DURING OPERATION Avoid an extended period of direct air flow for your health W A R N I N G Should abnormal situation ...

Page 9: ...unt of heat in the room is above the cooling or heating capability of the unit for example more people entering the room using heating equipments and etc the preset room temperature cannot be achieved This appliance is not intended for use by young children or infirm persons unless they have been adequately supervised by a responsible person to ensure that they can use the appliance safely Young c...

Page 10: ...unit indicators Light indicator showing the operating condition Refer page 9 Horizontal deflector Vertical deflector Air Outlet Refer page 20 Remote controller Send out operation signal to the indoor unit So as to operate the whole unit Refer page 10 WIDTH mm 780 MODEL RAK 25NH5 RAK 35NH5 HEIGHT mm 280 DEPTH mm 210 MODEL NAME AND DIMENSIONS ...

Page 11: ...about once every one hour when frost forms on the heat exchanger of the outdoor unit for 5 10 minutes each time TIMER LAMP This lamp lights when the timer is working TEMPORARY SWITCH TEMPORARY SWITCH Press Temporary Switch Non conductor Stick TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work Use non conductor stick example toothpick By pressing the tempora...

Page 12: ...PERATURE buttons Use these buttons to raise or lower the temperature setting Keep pressed and the value will change more quickly TIME button Use this button to set and check the time and date RESET buttons FUNCTION selector Use this button to select the operating mode Every time you press it the mode will change from AUTO to HEAT to DEHUMIDIFY to COOL and to FAN cyclically FAN SPEED selector This ...

Page 13: ...th a beep Press the button again to stop operation You can raise or lower the temperature setting as necessary by maximum of 3 C Press the temperature button and the temperature setting will change by 1 C each time The preset temperature and the actual room temperature may vary somewhat depending on conditions The display does not indicate the preset temperature in the AUTO mode If you change the ...

Page 14: ...ed is HI at first and varies to MED or LOW automatically when the preset temperature has been reached HI Economical as the room will become warm quickly But you may feel a chill at the beginning MED Fan speed slow LOW Fan speed slower Set the desired room temperature with the TEMPERATURE buttons the display indicates the setting The temperature setting and the actual room temperature may vary some...

Page 15: ...temperature setting The function will stop the indoor unit will stop emitting air as soon as the room temperature becomes lower than the setting temperature Set the desired room temperature with the TEMPERATURE button the display indicates the setting The range of 20 26 C is recommended as the room temperature for dehumidifying Press the START STOP button Dehumidifying operation starts with a beep...

Page 16: ...ED Fan speed slow LOW Fan speed slower Set the desired room temperature with the TEMPERATURE button the display indicates the setting The temperature setting and the actual room temperature may vary some how depending on conditions Press the START STOP button Cooling operation starts with a beep Press the button again to stop operation The cooling function does not start if the temperature setting...

Page 17: ...re and setting temperature is large fan starts to run at HI speed After room temperature reaches the preset temperature the cooling operation which changes the fan speed and room temperature to obtain optimum conditions for natural healthful cooling will be performed For the cooling operation FAN OPERATION You can use the device simply as an air circulator Use this function to dry the interior of ...

Page 18: ...EL button The RESERVED sign goes out with a beep and the TIMER lamp turns off on the indoor unit 1 Set the current month and day with the TIMER control button 1 Press the OFF TIMER button The OFF mark blinks on the display 1 Press the ON TIMER button the ON mark blinks on the display 2 Set the turn off time with the TIMER control button Press the RESERVE button 3 Press the ON TIMER button so that ...

Page 19: ...th the TIMER control button The setting of turn off time is now complete Example The device will turn off at 11 00p m Example The device will turn on at 7 00 a m The setting of the turn on time is now complete 4Set the turn on time with the TIMER control button 5 Point the signal window of the remote controller toward the indoor unit and press the RESERVE button The ON mark starts lighting instead...

Page 20: ...ller The TIMER lamp lights with a beep from the indoor unit When the sleep timer has been set the display indicates the turn off time Example If you set 3 hours sleep time at 11 38 p m the turn off time is 2 38 a m 2 Press the SLEEP button and set the sleep timer The device will be turned off by the sleep timer and turned on by on timer How to Cancel Reservation Point the signal window of the remo...

Page 21: ...sleep timer can not be set If you set the sleep timer after the off on off or off on timer has been set the sleep timer becomes effective instead of the off on off or off on timer set earlier You can not set other timer during sleep timer operation After sleep timer time is up and when press sleep button again the sleep timer will be set as last setting Sleep timer effective only once NOTE ...

Page 22: ...usting range shown on the right When the operation is stopped the horizontal air deflector moves and stops at the position where the air outlet closes CAUTION In Cooling operation do not keep the horizontal air deflector swinging for a long time Some dew may form on the horizontal air deflector and dew may drop RESET Adjustment of the conditioned air in the upward and downward directions The horiz...

Page 23: ...e old batteries 2 Install the new batteries The direction of the batteries should match the marks in the case 1 Do not use new and old batteries or different kinds of batteries together 2 Take out the batteries when you do not use the remote controller for 2 or 3 months CAUTION Push and pull to the direction of arrow ...

Page 24: ...with your wake up time in the morning This will enable you to enjoy a comfortable room temperature Please use the timer effectively Dusty air filter will reduce the air volume and the cooling efficiency To prevent from wasting electric energy please clean the filter every 2 weeks Please pay attention to the room temperature and air flow direction when operating the unit for baby children and old f...

Page 25: ...e used for a long period of time please switch off the power from the mains If the power from mains remains ON the indoor unit still consumes about 8W in the operation control circuit even if it is in OFF mode Warning To protect the whole unit during lightning please stop operating the unit and remove the plug from the socket OFF Interference From Electrical Products Caution To avoid noise interfe...

Page 26: ...ied out only by qualified service personal Before cleaning stop operation and switch off the power supply CAUTION CAUTION Do not bend the air cleansing and deodorizing filter as it may cause damage to the structure NOTE In case of removing the air cleansing and deodorizing filters please follow the above procedures The cooling capacity is slightly weakened and the cooling speed becomes slower when...

Page 27: ... soft bristle brush Allow filters to dry in shade 3 Re insert the air cleansing and deodorizing filter to the filter frame Set the filter with FRONT mark facing front and slot them into the original state After attaching the filters push the front panel at three arrow portions as shown in figure and close it CAUTION Do not wash with hot water at more than 40 C The filter may shrink When washing it...

Page 28: ...he front panel with both hands to detach and attach it CAUTION Do not splash or direct water to the body of the unit when cleaning it as this may cause short circuit Never use hot water above 40 C benzine gasoline acid thinner or a brush because they will damage the plastic surface and the coating Removing the Front Panel When the front panel is fully opened with both hands push the right arm to t...

Page 29: ...QUALIFIED SERVICE PERSONAL EITHER EVERY HALF YEARLY OR YEARLY CONTACT YOUR SALES AGENT OR SERVICE SHOP Is the earth line disconnected or broken Is the mounting frame seriously affected by rust and is the outdoor unit tilted or unstable Is the plug of power line firmly plugged into the socket Please ensure no loose contact between them Air Blow Cleaning and maintenance must be carried out only by q...

Page 30: ...ks to it So the air filter and the evaporator regularly must be cleaned to reduce the odor Please contact your sales agent immediately if the air conditioner still fails to operate normally after the above inspections Inform your agent of the model of your unit production number date of installation Please also inform him regarding the fault Power supply shall be connected at the rated voltage oth...

Page 31: ... 29 MODEL RAK 25NH5 RAK 35NH5 ...

Page 32: ... 30 CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR MODEL RAC 25NH5 RAC 35NH5 165 56 28 750 852 76 570 95 166 559 26 16 280 195 340 280 ...

Page 33: ... 7 62 1 20 0 68 0 OFF 16 0 60 8 20 7 69 3 ON 24 7 76 5 28 0 82 4 OFF 24 0 75 2 28 7 83 7 ON 32 7 90 9 36 0 96 8 OFF 32 0 89 6 36 7 98 1 M RED BLK WHT YEL BLU 35V 5V 0V 0 5V FG MODEL RAK 25NH5 RAK 35NH5 POWER SOURCE DC 5V 35V DC360V OUTPUT 25W 40W Control circuit built in BLU BLUE YEL YELLOW BRN BROWN WHT WHITE GRY GRAY ORN ORANGE GRN GREEN RED RED BLK BLACK PNK PINK VIO VIOLET RED 360V BLK 0V WHT ...

Page 34: ...8 F 75 C 167 F RESISTANCE VALUE CAUTION When the refrigerating cycle has been operated for a long time with the capillary tubes clogged or crushed or with too little refrigerant check the color of the refrigerating machine oil inside the compressor If the color has been changed conspicuously replace the compressor 2M 1 05 2M 1 28 U V W M M M WHITE YELLOW RED RAC 25NH5 RAC 35NH5 JU1012D ...

Page 35: ... C501 10 CN14 CN10 RED CN9 BLU CN8 WHT CN15 WHT CN13 CN11 5 5 CN12 CN12 RED GRY 2A FUSE ICP RELAY R008 R007 3A FUSE 25A FUSE C006 R001 BLK GRN WHT WHT BRN RED BLK CONNECTING CORD BRN RED BLK BLK GRN RED BLK WHT YEL BLU POWER CIRCUIT TERMINAL BOARD GRN YEL L N C D SINGLE PHASE AC220 230V 50Hz GRN YEL THERE ARE SOME LEAD WIRES WHICH HAVE SPIRAL STRIPES WITH WHITE IN ADDITION TO THE ORIGINAL COLOR CN...

Page 36: ...EG2 SEG1 SEG0 SEG43 SEG42 SEG41 SEG40 P40 P41 P42 P43 P00 P01 P02 P03 P10 P11 P12 P13 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 BEEP P20 P30 P31 NCVL C1 VL C2 VL C3 XC IN XC OUT VDD X OUT X IN RESET CARR P23 P22 P21 VSS IC 1 M3455OM6A 504FP LCD 1 C8 50v 1u K 1 D3 RB425D 1 2 K2K3 K4 K5 P10 P11 P12 K6 K7 K8 K9 K10 K11K12 K18 K17 K15 K16 K13 K14 D0 D1 D2 D3 R1 100k SW1 R2 P 100k R3 100k R4 100k R5 Q1 2SC3443 or ...

Page 37: ...CIRCUIT DIAGRAM MODEL RAK 25NH5 RAK 35NH5 37 ...

Page 38: ...CIRCUIT DIAGRAM MODEL RAC 25NH5 RAC 35NH5 39 ...

Page 39: ... 41 PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAK 25NH5 RAK 35NH5 MAIN P W B Marking on P W B ...

Page 40: ... 42 MODEL RAK 25NH5 RAK 35NH5 RECEIVING P W B Marking on P W B ...

Page 41: ... 43 MODEL RAC 25NH5 RAC 35NH5 MAIN P W B Marking on P W B COMPONENT SIDE ...

Page 42: ...rmistor Room temperature thermistor Reset circuit Initial setting circuit Temporary switch Electric Expansion valve drive circuit Electric Expansion valve Outdoor microcomputer HIC AX 8T Trip signal synthesis circuit L N RAK 25NH5 RAC 25NH5 RAK 35NH5 RAC 35NH5 SPM2 Outdoor unit Terminal board Indoor microcomputer AX 7R ...

Page 43: ... mode other than during preseating cooling is recovered at 18 33ßC Set to ultra Lo Lo or stop depending on the room temperature and time Set to stop if the room temperature is 18ßC in the ultra Lo mode other than during preseating cooling is recovered at 18 33ßC The fan speed is controlled by the heat exchanger temperature the overload control is executed as in the following diagram See page 55 Sa...

Page 44: ... min 1 178 FWSS_M 500 min 1 500 min 1 179 FWSOY_M 600 min 1 700 min 1 17A FWS_M 750 min 1 820 min 1 17B FWKAF_M 850 min 1 920 min 1 17C FWL_M 850 min 1 920 min 1 17D FWAH_M 1050 min 1 1120 min 1 17E FWH_M 1050 min 1 1120 min 1 17F FWHH_M 1170 min 1 1250 min 1 180 FCSOY_M 600 min 1 680 min 1 181 FCS_M 750 min 1 780 min 1 182 FCL_M 870 min 1 950 min 1 183 FCAH_M 980 min 1 1030 min 1 184 FCH_M 1030 m...

Page 45: ...ressor maximum rpm CMAX will maintain for 60 minutes if indoor temperature is lower than CLMXTP No time constrain if indoor temperature is higher than CLMXTP 6 When fan is set to Hi compressor rpm will be limited to CKYMAX 7 When fan is set to Med compressor rpm will be limited to CJKMAX 8 When fan is set to Lo compressor rpm will be limited to CBEMAX 9 During Cool Dashed when room temperature rea...

Page 46: ... the indoor fan is set to sleep Lo 3 30 minutes after the sleep key is set the sleep shift of temperature starts and upper shift is made at least 6 times If 25 C is not reached after 6 shifts shifts repeat unit 25 C is reached 4 The sleep shift upper value of set temperature is 28 C 5 After 6 hours a shift down to the initial set temperature is made at a rate of 0 33 C 5 min 6 If the operation mod...

Page 47: ...he time 2 C 2 The indoor fan is operated in the Lo mode During thermo OFF indoor fan will be OFF for 5 minutes and ON for 1 minute 3 When the operation is started by the themostat turning ON the start of the indoor fan is delayed 32 seconds after the start of compressor operation 4 The compressor is operated forcedly for 3 minutes after operation is started 5 The minimum ON time and OFF time of th...

Page 48: ...ntinue in Fuzzy control mode 4 Compressor minimum ON time and OFF time is 3 minutes 5 During normal heating mode compressor maximum rpm WMAX will maintain for 120 minutes if indoor temperature is higher than 18 C No time limit constrain if indoor temperature is lower than 18 C and outdoor temperature is lower than 2 C 6 During Hotkeep or Defrost mode indoor operation lamp will blink at interval of...

Page 49: ...operation the changed operation mode is set and sleep control starts 6 The indoor fan speed does not change even when the fan speed mode is changed Lo 7 When defrosting is to be set during sleep operation defrosting is engaged and sleep operation is restored after defrosting 8 When operation is stopped during sleep operation the set temperature when stopped as well as the time continue to be count...

Page 50: ...ALVE 3 8 INDOOR UNIT SINGLE ENDED UNION 3 8 COMPRESSOR SINGLE ENDED UNION 1 4 SERVICE VALVE 1 4 ELECTRIC EXPANSION VALVE STRAINER STRAINER CHARGING PIPE HEATING OUTDOOR UNIT REVERSING VALVE SUCTION TANK SERVICE VALVE 3 8 INDOOR UNIT SINGLE ENDED UNION 3 8 COMPRESSOR SINGLE ENDED UNION 1 4 SERVICE VALVE 1 4 ELECTRIC EXPANSION VALVE STRAINER STRAINER CHARGING PIPE ...

Page 51: ...SWING CLOSING AIR DEFLECTOR 1 DOWNWARD 2 UPWARD INITIALIZE 1 DOWNWARD INITIALIZE 1 DOWNWARD 2 UPWARD STOP AT THE MOMENT START SWINGING 1 DOWNWARD 2 UPWARD 3 DOWNWARD STOP AT THE MOMENT START SWINGING 1 DOWNWARD 2 UPWARD 3 DOWNWARD STOP AT THE MOMENT ONE SWING CLOSING AIR DEFLECTOR 1 DOWNWARD 2 UPWARD INITIALIZE AT NEXT OPERATION INITIALIZE AT NEXT OPERATION STOP DURING ONE SWING STOP DURING SWINGI...

Page 52: ...he microcomputer starts operation When power OFF voltage drops and reaches 4 2V pin 1 of IC521 is set to Low This will RESET the microcomputer DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAK 25NH5 RAK 35NH5 1 Reset Circuit Fig 1 1 Fig 1 2 2 1 5 3 7 NORMAL HI RESET LO RES Microcomputer C524 R551 C522 C521 R522 5V 0V IC521 Voltage 5 0V Reset enter at 4 2V Reset release at 4 4V voltage 5 0V Voltage a...

Page 53: ... 64 ...

Page 54: ... 65 ...

Page 55: ... 66 ...

Page 56: ... 67 ...

Page 57: ...obably activate In case of active module faulty or defective connection Although the compressor continues to operate normally the power factor will decrease the operation current will increase and the overcurrent breaker of the household power board will probably activate Reference If diode stack 1 is faulty the compressor may stop due to lp anbormally low speed etc immediately after it starts or ...

Page 58: ...ressor and also absorb external noise entering from power line to protect electronic parts 6 Surge absorber Varistor 1 2 3 absorbs external power surge 7 Inrush protective resistor R007 R008 This works to protect from overcurrent when power is turned on Reference When inrush protective resistor is defective diode stack may malfunction As a result DC voltage is not generated and no operation can be...

Page 59: ...ed by amp This signal is superimposed to DC 35V line via C801 and L801 To prevent erroneous reception the outdoor microcomputer is designed so that it cannot receive a signal while it is outputting a request signal The receiving circuit in the indoor unit consists of a comparator and transistor The interface signal from the outdoor unit on the DC 35V line is supplied to C821 where DC components ar...

Page 60: ...eceive input SDI MICROCOMPUTER 5V 0V 5V 5V 12V 5V 5V 5V 5V 5V 5V C802 R813 L801 R812 Q803 C803 C804 R811 Q802 Q801 R824 3 2 1 R822 R806 R807 R805 R803 R804 5 7 6 IC801 R810 50 49 IF transmit output SDO HIC IF receive input SDI MICROCOMPUTER 11 30 68 29 0V L801 L802 C801 C809 R802 Q801 5V 0V R801 R803 0V 0V 0V 0V 0V 0V 0V 0V C808 NF COIL2 C810 C802 C806 C807 C812 C811 Interface relay 35V Communicat...

Page 61: ...Indoor microcomputer 4 95ms Transmit receive switching time 33ms 1 frame Outdoor HIC 30 Pin 0V 29 Pin 5V 0V 50 Pin 5V 0V 49 Pin 5V 0V DC 35V line 35V Fig 2 2 Voltages Waveforms of indoor Outdoor Microcomputers Outdoor to Indoor Communications Fig 2 3 Voltages Waveforms of indoor Outdoor Microcomputers Indoor to Outdoor Communications ...

Page 62: ... 33 3ms x 8 4 95ms 371 35ms Outdoor message Indoor message Example When the outdoor message is all 0s and indoor message is all 1s 36 V 35 V 34 V When reset approx 10ms Transmit receive switching time 4 95ms Character No 0 33 3ms 1 33 3ms 2 33 3ms 3 33 3ms Character No 0 33 3ms 1 33 3ms 2 33 3ms 3 33 3ms Bit No 0 Bit No 0 0 7 0 7 0 7 0 7 7 0 7 0 7 7 Leader 100ms When reset approx 10ms Leader 100ms...

Page 63: ... minimum rotation speed 3 Compressor minimum rotation speed 2 Compressor minimum rotation speed 1 Compressor minimum rotation speed 0 LSB 7 0 6 0 5 0 4 0 3 0 2 0 1 1 0 0 7 1 0 6 1 0 5 1 0 4 1 0 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 1 0 3 1 0 2 1 0 1 0 0 1 0 Character No Bit No Data 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 Fan 7 step request Actual compressor rotation speed 5 MSB Actua...

Page 64: ... the upper arm and the three transistors on the negative d side the lower arm W U V W W V V U U A DC Compressor motor U coil V coil W coil System Power module 2 C501 C502 C503 R24 0 35 m H Power relay Coil R007 R008 Inrush current protection relay C006 R001 Noise filter coil L N Terminal board FUSE 25A Fig 3 1 Power module circuit U is ON V is ON ...

Page 65: ...proportional to duty ratio ON time ON time OFF time of this chopper signal Time T in Fig 3 2 shows the switching period and relation with rotation speed N of the compressor is shown by formula below Fig 3 2 Switching order of power module N 60 2 X 1 T Fig 3 3 shows voltage waveform at each point shown in Figs 3 1 and 3 4 First half of upper arm is chopper second half is ON and first half of lower ...

Page 66: ...f power module Lighting mode when operated with compressor leads disconnected 1 Disconnect connector of 3 pole WHT YEL RED lead wire connecting to compressor located at the lower part of electric parts box 2 Set to compressor operation state other than FAN mode and press Start stop switch of remote control 3 If normal operation continues for more than 1 minute LD303 lights power module is consider...

Page 67: ...12 R919 R925 R924 ZD904 C909 15 1 2 JW8 JW8 4 3 In the power circuit for P W B power supply for microcomputer peripheral circuits and system power module driver circuit and as well as DC 35V are produced by switching power circuit Switching power circuit performs voltage conversion effectively by switching transistor IC901 to convert DC 330V voltage to high frequency of about 20kHz to 200kHz Trans...

Page 68: ...ing to IC901 Reference If the power circuit for P W B seems to be faulty 1 Make sure that 5V and 12V on the control P W B upper arm U V and W and the lower arm power voltage are the specified values 2 When only the 5V output is low REG 1 regulator faulty 5V 0V shorted output is too high or REG 1 is abnormal 3 When 12V and 5V are abnormal The following defects can be considered 1 Fan operation powe...

Page 69: ...tester When collector voltage of Q701 is measured 3 1 16 24 I F 0V 0V Fig 5 1 D702 CN2 Q701 DC voltmeter or tester Reversing valve R701 R703 R219 Q705 FUSE RESISTOR MICROCOMPUTER PQ701 1 2 3 4 5V HIC I F 35V R702 V Operation condition Collector voltage of Q701 Cooling Heating Dehumidifying General operation of Cooling In normal heating operation MAX rotation speed instructed by indoor microcompute...

Page 70: ...ignal B reference voltage 1 2Vd Detection point W W U U U V V W V To detect U phase voltage at point C is produced by driving motor induced voltage signal voltage at point A and 1 2 voltage of Vd voltage at point B and comparing with comparator For V phase and W phase voltage at point D and voltage at point E are produced in the same way as above Voltage at point C is taken into indoor unit microc...

Page 71: ...put from microcomputer is input to IC1 and is inverted by active Lo to become 0 15V drive signal it is then drive the transistor of each phase Fig 7 1 6 5 4 3 2 1 MICROCOMPUTER A R512 R521 R511 R510 R509 R508 R507 10 9 4 3 2 1 8 7 6 5 1 13 14 15 16 17 18 1 23 11 8 7 5 4 10 6 3 9 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 19 20 21 2 3 4 5 6 7 8 9 10 12 22 B B B 45 44 4...

Page 72: ... U Drive signal at point B Drive signal at point A V U W V U V W U V W Low speed rotation mode High speed rotation mode V U W V U U V 5V 0V W V V W U U V 15V 0V W V W U W U V W Drive signal at point B Drive signal at point A Fig 7 2 Fig 7 3 ...

Page 73: ...hen set value exceeds input voltage Voltage amplifies DC current level detected by the detection resistor and inputs this to microcomputer Internal or external overload is judged in microcomputer Produces reset voltage Modulates chopper signal to drive signal and stops according to presence ab sence of lp signal or reset signal 59 17 61 48 58 62 60 Is D104 L CT1 N R005 0V 0V 0V 0V R221 C218 12V R2...

Page 74: ... 0V 0V R43 0V R41 QC R42 SPM2 SPM2 HIC Main P W B HIC IC1 CN14 IP Outdoor microcomputer F R43 9 9 8 20 9 2 39 17 B The Ip cut off circuit detects an instantaneous excessive current and stops inverter to protect parts such as SPM2 etc As shown in diagram if current exceeding 21A flows voltage at point recognized by detecting resistor is input to pin of SPM2 HIC and voltage divided by R41 and R43 is...

Page 75: ... speed internal judgement value OVL judgement with respect to externally set value A D converter A D converter Judgement OVL according to the rotation speed Selects data according to the rotation speed and DC voltage OVL start current data Rotation speed data Motor control process Microcomputer Detection resistor Fig 8 4 Overload Control System Configuration Fig 8 5 DC current Rotation speed 1 Ove...

Page 76: ...d to a voltage and supplies it to the microcomputer Receiving this the microcomputer converts it to a digital signal and compares it with the internal data to judge whether or not overload control is required During overload control The filter consisting of R245 and C217 removes high harmonic components from the voltage generated from the DC current flowing to the detection resistor and supplies i...

Page 77: ...t varies when the supply voltage varies This control method copes with variations in the voltages as follows 1 Turns on the power module s U and V transistors so the current flows to the motor windings as shown in Fig 8 9 2 Varies the turn ON time of the W transistor according to the DC voltage level and the start is controlled so the start current is approx 10A as shown in Fig 8 10 Fig 8 8 DC cur...

Page 78: ... defrosting condition command to the indoor microcomputer via the circuit interface The microcomputer always reads the outdoor temperature via a thermistor microcomputer pin 64 and transfers it to the indoor unit thus controlling the compressor rotation speed according to the value set at the EEPROM in the indoor unit and switching the operation status outdoor fan on off etc in the dry mode The fo...

Page 79: ...and 5V line voltages rise and 12V line voltage reaches 10 9V and reset voltage input to pin 48 of microcomputer is set to Hi Reset voltage will be hold Hi until the 12V line voltage drops to 9 90V even though the power shuts down Microcomputer R252 R289 0V 0V R288 0V 5V 12V HIC R284 JW10 IC5 1 2 C204 48 RESET Main P W B Fig 10 1 C215 R286 C225 C107 C226 R285 0V 1 3 2 62 8 0V 0V R292 12V line 12V l...

Page 80: ...top Motor will output FG pulse by following this motor revolution Outdoor Microprocessor will output PWM control signal from FMCHOP terminal by following the instruction from indoor Microprocessor This PWM control signal will convert to Vsp voltage by smoothing circuit Q101 RC filter Fan motor will start to rotate when Vsp was proceeding over than 1 7V and generate FG pulse by rotation speed FG pu...

Page 81: ...wing inside of outdoor unit by snowing It may make Fan Lock Stop by strong wind ex 17m sec or above against the Fan rotation In this case unit will be restart again after a while In case of Fan Lock Stop even though the DC Fan Motor is rotating correctly the possible casue is Fan Motor problem or PQ102 on board or control board problem Stop after the Fan motor runs 2 minutes Fan Motor may be broke...

Page 82: ...ut voltage 12 Power Factor Control Circuit Assuming the same current capacity 20A power can be used about 10 effective comparing with curent use power factor of 90 and maximum capacity is thereby improved I input current V input voltage Invalid power area Even if voltage is applied current does not flow Effective voltage area input voltage input current Effective voltage area ...

Page 83: ... Wait for 3 4 minutes until it is defrosted If the air conditioner operates in cooling mode when it is cold the evaporator may get frosted Normal sound when refrigerant flows in pipe Compressor may not operate when room temperature is 10 C or less It also stops when the humidity is preset humidity or less It occurs during defrost ing Wait for 5 10 minutes until the condenser is defrosted At the be...

Page 84: ...y before stopping operation At this point fan speed is automatic This is because Nice temperature reservation function is operating This function starts operation earlier so the preset temperature is reached at the preset time Operation may start maximum 60 minutes before the preset time It does not work It works only during cooling and heating This is because Nice temperature reservation function...

Page 85: ...ling capability so noise becomes slightly louder This does not indicate a fault Noise from the outdoor unit occasionally changes The compressor rotation speed changes according to the difference between the thermostat set temperature and room temperature This does not indicate a fault There is a difference between the set temperature and room temperature There may be a difference between the set t...

Page 86: ...he ground level 2 Also note that it takes about 10 minutes until the voltage fall after the power switch is turned off DANGER Across a b 0V line Across a ground Across b 0V line ground approx 260 360V approx 155 170V approx 155 170V When using an oscilloscope never ground it Don t forget that high voltages as noted above may apply to the oscilloscope DANGER Always keep your hands and metallic thin...

Page 87: ...rcuit in indoor unit electrical parts disconnect red gray lead wire connected from diode stack to system power module SPM2 to prevent secondary trouble Be sure to discharge smoothing capacitor Do not use a soldering iron with transformer If one is used thermal fuse inside transformer will be blown DISCHARGE PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT WARNING As shown above apply solderin...

Page 88: ...blinking Yes Yes Yes Yes No No No Normal No No Timer lamp Press the service switch for 1 sec Does the compressor operate After checking be sure to press the service switch to stop the operation Check the refrigerating cycle Check the outdoor electrical parts Check the indoor electrical parts Check to see whether the F cable is connected incorrectly or disconnected See Out door unit self diagnosis ...

Page 89: ... unit IC401 or IC402 data reading error When data read from IC401 or IC402 is incorrect 1 Reversing valve defective 2 Heat exchanger thermistor disconnected only in the heating mode Note The malfunction mode is entered the 3rd time this abnormal indication appears read every 3 minutes Electrical parts in the outdoor unit 1 Indoor interface circuit 2 Outdoor interface circuit Please check at the ou...

Page 90: ... 101 SELF DIAGNOSIS LIGHTING MODE MODEL RAC 25NH5 RAC 35NH5 ...

Page 91: ...g generated between terminals C and D on the terminal board Are control voltages 12V 5V being generated normally Check according to the proper method for checking the power circuit No No No No Yes Yes Do the air deflectors perform initial operation when the power supply is turned on and off Check the indication P W B connection cord and light receiving unit No No Is the microcomputer reset input p...

Page 92: ... 103 2 Outdoor unit does not operate but receives remote infrared signal ...

Page 93: ...nly indoor fan does not operate other is normal 4 Air deflector does not move others are normal 5 All systems stop from several seconds to several minutes after operation is started all indicators are also off ...

Page 94: ... 105 6 Check the main P W B power circuit ...

Page 95: ... 106 CHECKING THE REMOTE CONTROLLER ...

Page 96: ...l See the description on power circuit for details Is 5V being generated between Pin 4 0V and pin 3 5V at CN 18 test pin Operate the outdoor unit according to the instruction How to operate the outdoor unit independently How did the self diagnosis lamp LD301 light Is the switching power circuit OK Has the 3A fuse blown See the self diagnosis lamp lighting mode Check to see whether the connected C ...

Page 97: ...g supplied across the control side coil terminal of interface relay Is a voltage at least 10V being generated between the contact terminals of interface relay Check the interface curcuit Yes Yes No No Yes D907 and C910 may be defective There is a defective section between the 12V output of switching power supply on the main P W B and interface relay also check for contact with solder etc Repalce t...

Page 98: ...be forgetting to connect after servicing Is the continuity of thermistor normal Is the thermistor circuit normal Replace the power module Replace any defective parts Connect the thermistor Replace the thermistor Replace parts in the thermistor circuit Check continuity of pattern and lead wires according to the P W B and schematic diagrams Check continuity of pattern and lead wires according to the...

Page 99: ...r circuit No No No Check continuity of new parts Check continuity of pattern and lead wires according to the P W B and schematic diagrams Yes Yes Replace system power module or defective parts Replace the system power module Replace any defective parts Is the thermistor circuit normal Are peripheral circuits of system power module normal Replace the main P W B Is the system power module normal Is ...

Page 100: ... 111 ...

Page 101: ...L lamp lit If the lamp is lit it does not indicate fault but the unit is overload status Recheck cord etc of the system power module If they are disconnected connect them securely If abnormality continues replace the system power module Overvoltage defect system power module faulty 14 times blinking Yes No ...

Page 102: ...n the same condition as above The compressor is defective Replace it and seal refrigerant If the compressor checker for an inverter type air conditioner is available re check using it JUDGING BETWEEN GAS LEAKAGE AND COMPRESSOR DEFECTIVE Blinking off Time until the lamp lights Approx 10 seconds Approx 10 seconds Approx 10 seconds Within Approx 30 seconds Compressor Compressor Gas leakage Possible m...

Page 103: ...e of digital tester since built in battery is set in reverse direction and terminals are reversed CAUTION If inner circuit of system power module is disconnected open the indicator of tester will not swing and this may assumed as normal In this case if indicator swings when and terminals are connected in reverse of diagram below it is normal Furthermore compare how indicator swings at U V and W ph...

Page 104: ...witch again to stop the forced cool operation HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY The operation method is the same as How to operate using the connector to servicing the outdoor unit 1 The charging amount of 300g is equivalent to the load in normal operation Charge refrigerant of 300g after vacuuming 1 Do not operate for more than 5 minutes Parts to be prepared 1 Reducing union 2 8 6 35m...

Page 105: ...E Collector Emitter PGU PGV PGW NGU NGV NGW U V W P1 P2 U N1 L2 L1 W V Circuit diagram of the device excepting the reflux diode Circuit diagram of the module Terminals symbol mark of the module See next page for measuring value using tester ...

Page 106: ... 117 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAK 25NH5 RAK 35NH5 ...

Page 107: ...7 1 TERMINAL BOARD 2P 18 PMRAS 260GHA 001 1 THERMISTOR ASSEMBLY 20 PMRAK 25NH5 001 1 P W B MAIN 21 PMRAS 25YH4 922 1 P W B RECEIVER 25 PMRAS 25YH4 926 1 DRAIN PAN 28 PMRAS 25YH4 929 1 AUTO SWEEP MOTOR 32 PMRAS 25YH4 933 1 FRONT COVER ASSEMBLY 35 PMRAS 25YH4 936 1 FRONT PANEL 36 PMRAS 25YH4 937 1 AIR FILTER R 37 PMRAS 25YH4 938 1 AIR FILTER L 38 PMRAS 25YH4 939 1 LOWER COVER 39 PMRAS 25YH4 940 1 MO...

Page 108: ...7 1 TERMINAL BOARD 2P 18 PMRAS 260GHA 001 1 THERMISTOR ASSEMBLY 20 PMRAK 35NH5 001 1 P W B MAIN 21 PMRAS 25YH4 922 1 P W B RECEIVER 25 PMRAS 25YH4 926 1 DRAIN PAN 28 PMRAS 25YH4 929 1 AUTO SWEEP MOTOR 32 PMRAS 25YH4 933 1 FRONT COVER ASSEMBLY 35 PMRAS 25YH4 936 1 FRONT PANEL 36 PMRAS 25YH4 937 1 AIR FILTER R 37 PMRAS 25YH4 938 1 AIR FILTER L 38 PMRAS 25YH4 939 1 LOWER COVER 39 PMRAS 25YH4 940 1 MO...

Page 109: ... 120 8 9 33 4 32 14 3 27 24 35 26 7 5 22 17 30 29 23 21 20 16 28 31 11 12 10 15 6 2 38 1 OUTDOOR UNIT MODEL RAC 25NH5 RAC 35NH5 ...

Page 110: ...ST 15 PMRAM 40QH5 907 1 COIL REVERSING VALVE 16 PMRAC 18SH4 901 1 REACTOR 17 PMRAC 25NH5 901 1 P W B MAIN 20 PMRAC 25NH4 912 1 SYSTEM POWER MODULE 21 PMRAC 40CNH2 902 1 DIODE STACK D25VB60 22 PMRAC 25NH4 913 1 TERMINAL BOARD 4P 23 PMRAC 40CNH2 916 1 THERMISTOR OUTSIDE TEMPERATURE 24 PMRAC 25CNH2 902 1 PROPELLER FAN 26 PMRAC 25NH4 914 1 SUPPORT FAN MOTOR 27 PMRAC 40CNH2 919 1 FAN MOTOR 40W 28 PMRAC...

Page 111: ...ST 15 PMRAM 40QH5 907 1 COIL REVERSING VALVE 16 PMRAC 18SH4 901 1 REACTOR 17 PMRAC 35NH5 901 1 P W B MAIN 20 PMRAC 25NH4 912 1 SYSTEM POWER MODULE 21 PMRAC 40CNH2 902 1 DIODE STACK D25VB60 22 PMRAC 25NH4 913 1 TERMINAL BOARD 4P 23 PMRAC 40CNH2 916 1 THERMISTOR OUTSIDE TEMPERATURE 24 PMRAC 25CNH2 902 1 PROPELLER FAN 26 PMRAC 25NH4 914 1 SUPPORT FAN MOTOR 27 PMRAC 40CNH2 919 1 FAN MOTOR 40W 28 PMRAC...

Page 112: ...HITACHI PM NO 0324E Printed in Malaysia RAK 25NH5 RAC 25NH5 RAK 35NH5 RAC 35NH5 ...

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Hitachi RAC-25NH5, Service Manual

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