Hitachi RAC-25CNH11 Service Manual Download

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3. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD

●

Run the unit by setting the operation mode to
(COOL), the temperature to 32°C and the fan speed
to HI for about half a day on a fine day, and dry the
whole of the unit.

●

Switch off the power plug.

REGULAR INSPECTION

PLEASE CHECK THE FOLLOWING POINTS BY 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 qualified service personal. Before cleaning,
stop operation and switch off the power supply.

CAUTION

Confirm

Summary of Contents for RAC-25CNH11

Page 1: ...LIST AND DIAGRAM 113 RAS 25CNH11 RAC 25CNH11 REFER TO THE FOUNDATION MANUAL INDOOR UNIT RAS 25CNH11 OUTDOOR UNIT RAC 25CNH11 WALL TYPE SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ROOM AIR CONDITIONER INDOOR UNIT OUTDOOR UNIT JANUARY 2003 H A P M TYPE MODEL 1ø 220V 50Hz POWER SOURCE 910 190 1 150 COOL 1 250 160 1 350 HEAT TOTAL INPUT 4 20 3 85 COOL 5 75 5 25 HEAT TOTAL AMPERES RA...

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 mor...

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: ...peration and then re started in a moment cooling 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 4 This room air conditioner should not be used at the cooling operation when the outside temperature ...

Page 6: ...CE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR REMOTE CONTROL SWITCH LIQUID CRYSTAL THERMOSTAT FUSE CAPACITY SPECIFICATIONS 690g UNIT PIPES 690g for piping set of 5 8m REFRIGERANT CHARGING VOLUME Refrigerant 22 WITHOUT REFRIGERANT BECAUSE COUPLING IS FLARE TYPE P 105 VK1 5m P 108 VK1 8m 20 W NO NO NO GR20DR2F NO YES YES 3A G4A NO NO YES NO NO NO NO YES YES NO NO 416NR YES NO NO NO NO YES YES IC 1...

Page 7: ...tape The insulator will deteriorate if it is not wrapped with tape The connection of insulated drain hose Please use insulated drain hose for the indoor piping commercial product inner diameter ø 16mm The indoor piping should be insulated with the enclosed insulation pipe If the insulator is insufficient please use commersial products Be sure to completely seal any gap with putty Direction of Pipi...

Page 8: ...he unit Without a circuit breaker the danger 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...

Page 9: ... deflector and drips down occasionally This will wet your furniture Therefore do not operate under such condition for a long time If the amount 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 Do not climb on the outdoor unit or put objects on it Pleas...

Page 10: ...ont panel Air Inlet 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 OUTDOOR UNIT DRAIN PIPE Condensed water drain to outside CONNECTING CORD AIR INLET BACK LEFT SIDE AIR OUTLET WIDTH mm 745 700 MODEL RAS 25CNH11 RAC 25CNH11 HEIGHT mm 248 570 DEPTH mm 175 210 MODEL NAME AND ...

Page 11: ...e in automatic mode OPERATION INDICATOR OPERATION LAMP This lamp lights during operation The OPERATION LAMP flashes in the following cases during heating 1 During preheating For about 2 3 minutes after starting up 2 During defrosting Defrosting will be performed about once an hour when frost forms on the heat exchanger of the outdoor unit for 5 10 minutes each time TIMER LAMP This lamp lights when...

Page 12: ...nge 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 determines the fan speed Every time you press this button the intensity of circulation will change from AUTO to ...

Page 13: ... Operation starts with 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 mod...

Page 14: ... warm quickly But you may feel a chill at the beginning MED Quiet LOW More quiet Set the desired room temperature with the TEMPERATURE buttons the display indicates the setting The range of 18 22 C is recommended as the room temperature for heating If the temperature setting is 20 C the room temperature will be controlled at around 20 C The temperature setting and the actual room temperature may v...

Page 15: ...ure setting The device will dehumidify the room reducing the room temperature to the preset level When the room temperature is lower than the temperature setting Dehumidifying will be performed at the temperature setting slightly lower than the current room temperature regardless of the temperature setting The function will stop the indoor unit will stop emitting air as soon as the room temperatur...

Page 16: ...with a beep Press the button again to stop operation The cooling function does not start if the temperature setting is higher than the current room temperature even though the OPERATION lamp lights The cooling function will start as soon as you set the temperature below the current room temperature Set the desired room temperature with the TEMPERATURE button the display indicates the setting The r...

Page 17: ...ture fan speed changes to LOW automatically When the difference of room temperature 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...

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: ...complete Example The device will turn off at 11 00p m Example The device will automatically turn on earlier so that the preset temperature can be reached 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 ins...

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: ...e will be controlled 5 C below the temperature and the FAN SPEED will be set to LOW setting 30 minutes after the setting of the sleep timer Operation with the sleep timer Sleep timer set 30 minutes later 1 hour later 3 hours later 7 hours later 2 hours later 5 C If date or current time is not set sleep timer can not be set If you set the sleep timer after the off on off or off on timer has been se...

Page 22: ...tor within the adjusting 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 When cooling dehumidifying When heating 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 some dew drops may fall from it RESET Adju...

Page 23: ...gether 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 TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work By setting the temporary switch the operation is done in previously set operation mode When the operation is done using the temporary switch after the power source is t...

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: ...ned and the cooling speed becomes slower when the air cleansing and deodorizing filters are used So set the fan speed to HIGH when using it in this condition Air cleansing and deodorizing filters are washable and reusable up to 20 times by using vacuum cleaner or water rinse under running tap water Type number for this air cleansing filter is SPX CFH5 Do not operate the air conditioner without fil...

Page 27: ... with hot water at more than 40 C The filter may shrink When washing it shake off moisture completely and dry it in the shade do not expose it directly to the sun The filter may shrink Do not use detergent on the air cleansing and deodorizing filter as some detergent may deteriorate the filter electrostatic performance Open the front panel and remove the filter Gently lift and remove the air clean...

Page 28: ... 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 Arm When the front panel is fully opened with both hands push the right arm to...

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: ...ation the following phenomena may occassionally occur but they are not abnormal for the operation 1 Slight flowing noise of refrigerant in the refrigerating cycle 2 Slight rubbing noise from the fan casing which is cooled and then gradually warmed as operation stops The odor will possibly be emitted from the room air conditioner because the various odor emitted by smoke foodstuffs cosmetics and so...

Page 31: ...12 16 55 570 428 700 243 53 236 210 10 482 517 135 75 77 P Air suction grill Top air suction grill Mounting plate Wireless remote controller Cabinet Front cover VIEWED FROM BACK PIPE LEAD OUT Discharge grill Vertical air deflector Horizontal air deflector Hole on the wall for ø65 mm pipe Line cord Connecting cable Narrow pipe ø6 35 Wide pipe ø9 52 Drain cap connection part When piping is drawn hor...

Page 32: ... 167 F TEMPERATURE C F INDICATION 16 INDICATION 24 INDICATION 32 MODEL RAS 25CNH11 THERMOSTAT MODEL IC ON 17 6 63 7 OFF 16 6 61 8 ON 25 6 78 1 OFF 24 6 76 3 ON 33 6 92 5 OFF 32 6 90 7 M RESISTANCE VALUE MODEL RAS 25CNH11 RAC 25CNH11 RATED VOLTAGE DC0 35V DC230V OUTPUT 20W 20W RED YELLOW BLUE 0 30V 5V U V W WHITE YELLOW RED ...

Page 33: ...pecifications CONNECTION 20 C 68 F 75 C 167 F RESISTANCE VALUE ORANGE RED WHITE 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 3 21 2M 3 90 U V W WHITE YELLOW R...

Page 34: ...WHITE BROWN RED WHITE WHITE WHITE WHITE RED WHITE RED YELLOW YELLOW YELLOW RED RED RED WHITE BLUE GRAY GRAY GRAY GRAY REV VALVE COIL OUTDOOR FAN MOTOR GRAY BROWN OUTDOOR TEMPERATURE THERMISTOR DEFROST THERMISTOR OVERHEAT THERMISTOR CN4 CN5 CN6 SWITCHING POWER SUPPLY SMOOTHING CAPACITOR 1000µF RUSH CURRENT PROTECTION BLUE BROWN BLUE BLUE YELLOW DIODE STACK YELLOW YELLOW RCI DIODE STACK CAPACITOR RE...

Page 35: ... 35 CIRCUIT DIAGRAM MODEL RAS 25CNH11 ...

Page 36: ... 37 CIRCUIT DIAGRAM MODEL RAC 25CNH11 ...

Page 37: ...ndoor micro computer AX 7J03 Outdoor micro computer 8E21 LCD wireless Room temperature thermistor Wireless receive circuit DC current signal Rotor magnetic pole position detection circuit Peak current cut off circuit Overload control circuit Voltage amplification circuit Over heat thermistor Defrost thermistor Outdoor temperature thermistor Indoor Outdoor interface circuit Power circuit Indoor uni...

Page 38: ...ooling Dehumidifying Super Lo Lo Overload Med Hi Super Hi Lo Med Hi Super Hi Lo Med Super Lo AFWSS AFWS AFWKAF AFWL AFWH AFWHH AFCS AFCL AFCH AFCHH AFDS AFDL AFDSS 9 8V 16 6V 19 1V 19 1V 27 7V 27 7V 16 0V 18 7V 20 9V 20 9V 16 0V 18 7V 15 0V Note 1 Refer to data in Table 1 and 2 for constants shown by capital letters in Table 3 Table 1 RAS 25CNH11 Model Data Required value of unit side Source file ...

Page 39: ...top according to the room temperature time and heat exchanger temperature When the heat exchanger temperature becomes 18 C or less except for the preheating operation mode Stop is set The operation recovers at 18 66 C Operation mode is changed to one of Lo Med Hi Super Hi and Stop according to the room temperature and time Super Hi operation is done when the compressor rotates at maximum or when r...

Page 40: ...shed and Pl control starts 4 The minimum ON time of the compressor is 3 minutes and minimum OFF time is also 3 minutes 5 The compressor speed in the fixed rotation period after releasing Cool dash maximum speed is the minimum speed CMIN 6 The time limit to keep the maximum speed CMAX of the compressor in the normal cooling operation other than Cool dash is within 60 minutes when the room temperatu...

Page 41: ... Lo mode OFF for 5 minutes and ON for 1 minute at high humidity or OFF for 6 minutes and ON for 1 minute at low humidity repeatedly according to the humidity judgement when the thermostat is turned OFF 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 minu...

Page 42: ... Cool rhythm operation starts during the cooling operation in the AUTO operation mode not during Cool dash and when the room temperature is the preset temperature 0 66 C or less 2 In Cool rhythm operation the temperature rising period is 10 minutes minimum and also temperature falling period is 10 minutes minimum 3 The Cool rhythm operation is not done during Nice temperature Sleep and Cool dash o...

Page 43: ...0 66 C when operation is started with start stop switch preheating mode is released when heat exchanger temperature YNEOF 9 Rotation speed of compressor is limited to the value of Rating for Heating WSTD 2000 2 min 1 or less in Low fan operation mode 10 In Super Low fan operation mode when room temperature drops below 18 C indoor fan operation will stop When room temperature reaches 18 C 0 66 C Su...

Page 44: ...in 15 minutes after the operation is started or after DEFROST is completed Note 1 Refer to data in Table 1 on page 41 for each constant shown in capital letters in the diagram 2 In the diagram s attached to the top right of number mean minute s means second ex 30 15 Reversing valve defrost WMAX Reversing valve Power ON mode in heating Operation lamp Outdoor fan Indoor fan Defrost signal Start Stop...

Page 45: ... 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 SWINGING STOP DURING SWINGING TEMPORARY STOP DURING SWINGING STOP DURING ONE SWING STOP DURING ON...

Page 46: ... computer Fig 1 2 shows the waveforms in each circuit when power is ON and OFF When the power is supplied the voltages on the 35V and 5V DC lines rise and when the 35V DC line becomes approx 24V ZD201 turns on and the voltage at the base of Q201 rises to turn Q201 on Since the collector of Q201 goes Lo at this time Q202 turns on and the reset input of the micro computer goes Hi The 5V DC line has ...

Page 47: ...Micro computer When the buzzer sounds an approx 3 9kHz square signal is output from buzzer output pin q of the micro computer After the amplitude of this signal has been set to 12Vp p by a transistor it is applied to the buzzer The piezoelectric element in the buzzer oscillates to generate the buzzer s sound Fig 3 1 Buzzer Circuit Sound wave Metal diaphragm V Pizoelectric element V Fig 3 2 Buzzer ...

Page 48: ...utput from pins k A of the micro computer Micro computer pins Step width Horizontal air deflectors 10ms 1 2 3 4 5 6 7 8 Horizontal air deflectors 51 50 49 48 Fig 4 2 Micro computer Output Signals As the micro computer s outputs change as shown in Fig 4 2 the core of the auto sweep motor is excited to turn the rotor Table 4 1 shows the rotation angle of horizontal air deflectors Rotation angle per ...

Page 49: ...erature input R308 A 5 4 3 2 1 0 0 10 10 Heat exchanger temperature C Fig 6 2 20 30 40 Voltage at V A 6 Heat exchanger temperature thermistor circuit The voltage at A depends on the room temperature as shown in Fig 5 2 The circuit detects the indoor heat exchanger temperature and controls the following 1 Preheating 2 Low temperature defrosting during cooling and dehumidifying operation 3 Detection...

Page 50: ... operation Fig 7 1 8 DC Fan Motor Drive Circuit Fig 8 1 shows the indoor DC fan motor drive circuit Fig 8 1 The circuit produces the fan motor drive voltages 8 33V from 35V DC supplied from the outdoor unit and controls the fan motor speed Q903 is switched on and off according to the signal at fan PWM output pin J to control the voltage which is smoothed by D901 L901 and C901 to drive the fan moto...

Page 51: ...between blue and red Characteristics Mode Fan Speed Connector blue red voltage V Rotation Speed min 1 SS 9 8 714 S 16 6 950 OVERLOAD 19 1 1 040 LO 19 1 1 040 HI 27 7 1 350 SUPER HI 27 7 1 350 S 16 0 930 LO 18 7 1 020 HI 20 9 1 100 SUPER HI 20 9 1 100 S 16 0 930 INDOOR FAN SPEED HEATING COOLING DEHUMIDIFYING ...

Page 52: ...9 1 DC 35V supplied from the outdoor unit is controlled by switching of regulator 1 and is smoothed by D102 L102 and C102 to produce 12V Output voltage is divided by R102 and R103 and input to output dividing pin 5 to control switching so that output voltage is 12V Fig 9 2 Waveform at A Waveform at Out put Voltage B ...

Page 53: ...ly Reference If the reactor is faulty or the connection is defective the compressor may stop due to abnormality in line voltage etc immediately after it is started Reference When diode become defective the compressor may stop due to abnormality in line voltage etc immediately after it is started or no operation may be done as a DC voltage is not generated between the positive and negative terminal...

Page 54: ...r This smoothes averages the voltage rectified by the diode stacks A DC voltage is generated in the same way as in Fig 1 3 5 C805 C808 C812 C813 L804 NF coil These absorb electrical noise generated during operation of compressor and also absorb external noise entering from power line to protect electronic parts 6 Surge absorber varistor 1 3 These absorbs external power surge 7 Inrush protective re...

Page 55: ...ransmitting circuit Transmitting circuit and receiving circuit of the outdoor unit are provided inside HIC Transmitting circuit intermits high frequency oscillation circuit of about 36kHz with comparator according to the request signal This high frequency signal is applified by the transistor and is ourput from HIC pin then superimposed with DC 35V line via C701 and L701 To prevent mis operation o...

Page 56: ...V OV OV OV OV OV OV OV OV OV OV OV 5V 5V 5V 5V 5V 5V 5V 5V R702 L701 C701 C702 C709 C710 C708 C706 12V OV R704 R703 OV OV D D C C OV C807 C805 R813 R813 Q801 R814 R815 R821 R822 5V 5V 5V 5V 5V R807 R807 R808 R809 R811 C804 R810 C803 R817 R819 R820 Q802 R818 C806 D801 COM801 IF receive input SDI Micro computer IF transmit output SDO COM801 H I C Inpoor P W B Outdoor P W B D101 Noise filter coil I F...

Page 57: ...in Pin Pin Pin 5V 0V 5V 0V 5V 0V 5V 0V 35V Indoor micro computer 35V DC line Outdoor HIC 4 95ms Transmit receive switching time 33ms 1frame Fig 2 2 Voltages Waveforms of indoor Outdoor Micro computers Outdoor to Indoor Communications Fig 2 3 Voltages Waveforms of indoor Outdoor Micro computers Indoor to Outdoor Communications 64 ...

Page 58: ...805 L804 R801 R802 80 F µ 1000 F µ DC current Id detect resistance 1 2 U coil V coil W coil DC compressor Motor u V W u v w u v w Power Module 0 0 0 0 0 0 3 Power Module Circuit Fig 3 1 shows the power module and its peripheral circuits The three transistors on the positive e side are called the upper arm and the three transistors on the negative d side the lower arm Fig 3 1 Power module circuit U...

Page 59: ...ime 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 Fig 3 3 Voltage waveform at each point When power is supplied U U because of that U is chopped current flows as show...

Page 60: ... 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 considered norm...

Page 61: ...ipheral circuits and power module drive and as well as DV35V are produced by switching power circuit Switching power circuit performs voltage conversion effectively by switching transistor Q1 to convert DC270V voltage to high frequency of about 20kHz to 70kHz Transistor Q1 operates as follows 1 Shifting from OFF to ON DC about 270V is applied from smoothing capacitors C810 and C811 in the control ...

Page 62: ... winding of transformer and is discharged to each secondary coil during OFF period Energy LI2 2 L Primary inductance I Current when Q1 is OFF Each coil C61 C67 is charged according to the winding ratio ZD3 turns ON Q2 to bypass Q1 base current during ON period to fix value of voltage in the direction of arrow For example when applied voltage to Q1 is high voltage in the direction of arrow will ris...

Page 63: ...it for P W B is estimated as abnormal 1 Check that power voltages of 5V 12V on the control P W B and also power voltage of upper arm U V and W and lower arm are specified values 2 Abnormal only when output of 5V voltage has decreased Regulator 1 is abnormal short circuited between 5V and 0V or output too high 3 When 12V and 5V voltage are abnormal 1 Mainly 2 Fan operation power or inrush current p...

Page 64: ...e on the terminal board By reversing valve control circuit you can switch reversing valve ON OFF according to instruction from indoor microcomputer and depending on operation condition Voltage at each point in each operation condition is approximately as shown below when measured by tester When collector voltage of Q701 is measured 3 1 Reversing valve CN2 D 701 Q 701 R 705 R 706 I F 0V 0 0 0 0 0 0...

Page 65: ... voltage at point A is phase shifted by 90 by passing lowpass filter consisting of R101 R104 and C101 to make triangular wave voltage at point B In HIC 3 phases of this triangular wave are synthesized to produce composite wave voltage at point C This composite wave becomes a triangular wave with period of 1 3 times compared with original triangular wave Voltages at points B and C are compared by c...

Page 66: ...rminal e and drives the upper arm transistors Fig 7 2 As described in the rotor magnetic pole position detecting circuit the upper arm drive circuit supplies current to the bases of the transistors on the power module s positive e side which turn on or off according to the position detection signals The signals according to the position detection detection signals are output from pins e r and t of...

Page 67: ...terminals R504 PQ501 Switching incomplete to cut off the upper arm transistors Fig 7 3 R507 is used to charge C501 initally The operation is the same for B and C phases 5 6 1 8 2 PQ2 7 b a 1 Bu Eu Power module A phase A 2 R401 R404 D401 D402 C401 R407 A Current at point Reverse bias current OA Fig 7 3 Waveform of Transistor Base Current Reverse Current at Point A ...

Page 68: ... upper lowerarm drive circuits stop When pin fi of the micro computer goes Lo Hi a photocoupler between PQ601 pins 1 and 2 turns on and current flows to terminal i R601 PQ601 R604 power module s BU terminals Ew terminals D602 D601 terminal k and drives the lower arm transistors Fig 7 4 The signals which turn on or off according to the position detection signals are output from pins fi of the micro...

Page 69: ...nput 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 Fig 8 1 Micro computer AX 8E21 and peripheral circuits 1 2 17 AVcc Vd Micro computer AX 8E21 ...

Page 70: ... 8 3 shows the Peak Current Cut off Circuit and Waveforms at Each Section Ip cut off circuit detects an instantaneous large current and stops drive output signal to protect parts such as power module etc As shown in the figure when current exceeding 18A flows voltage at point A detected by detection resistor is input to e terminal of COM A If it exceeds d terminal voltage which is the set value ou...

Page 71: ...and DC voltage OVL start current data Motor control process Detection resistor To power module negative terminal DC current R806 Overload externally set value circuit Voltage amp circuit External judgement Internal judgement DC voltage AX 8E21 Micro computer Rotation speed data Fig 8 4 Overload Control System Configuration External judgement value Judgement value according to the rotation speed in...

Page 72: ...al signal and compares it with the internal data to judge whether or not overload control is required During overload control The filter consisting of R201 and C202 removes high harmonic components from the voltage generated from the DC current flowing to the detection resistor and R205 and C206 average the voltage and supplies it to OP1 pin 5 OP1 forms a non inverting voltage amp circuit together...

Page 73: ...current 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 8A as shown in Fig 8 10 DC curren...

Page 74: ...base of Q2 goes Lo to turn Q2 OFF and also stops the operation current of PQ601 PQ603 to switch OFF the lower arm drive signal With the upper arm transistor drive circuit the base of Q1 goes Lo and the micro computer stop supplying a voltage to PQ501 PQ503 thus switching OFF the drive signal The peak current cut off Ip cut signal fixes the base of Q1 and Q2 in the upper lower arm transistor drive ...

Page 75: ...ted and stops operation When frost forms on the outdoor heat exchanger the temperature at the exchanger drops abruptly Therefore the resistance of the Defrost thermistor becomes high and the voltage at pin of HIC drops If this voltage becomes lower than the set value stored inside the micro computer starts defrosting control During defrosting operation the micro computer transfers the defrosting c...

Page 76: ...ltage input to pin of microcomputer is set to Hi By ZD501 reset voltage maintains input of pin at L0 until VDD of microcomputer rises to 5V to obtain operable status When power is shut off and potential of 12V is lowered ZD501 is shifted to OFF However since reset voltage is feed back to Q2 by R4 Q2 maintains ON state until 12V line voltage drops to about 7 6V This prevents reset voltage from chat...

Page 77: ...TING CAPILLARY CHEK VALVE FILLING PIPE HEATING CAPILLARY COMPRESSOR REFRIGERATING CYCLE DIAGRAM COOLING OUTDOOR UNIT REVERSING VALVE SUCTION TANK SERVICE VALVE 3 8 INDOOR UNIT SINGLE ENDED UNION 3 8 SINGLE ENDED UNION 1 4 COOLING HEATING CAPILLARY CHEK VALVE FILLING PIPE HEATING CAPILLARY COMPRESSOR HEATING OUTDOOR UNIT ...

Page 78: ...is the case of in A4 A temperature slightfy lower than the actual room temeprature becomes the set temperature and the dehumidifying operaion is done if possible Though the preset room temperature is set higher than actual room temperature using the remote controller dehumidifying operation is done The dehumidifying mode operates as follows by comparing the preset room temperature and the actual r...

Page 79: ...g defrosting Walt for 5 _ 10 minutes until the outdoor unit is defrosted At the begining of the heating operation the fan speed is held to Lo for 30 seconds If Hi is selected operation is done at Lo first then Med for 30 seconds and then is switched to Hi If the external temperature is too high heating operation may stop to protect the unit Auto fresh defrosting is carried out The system checks th...

Page 80: ...ed by 2o C in cooling operation each mode will operate in the following conditions Cooling Room temperature is higher than about 25o C Dehurnidifying Room temperature is about 21o C 25 o C Heating room temperature is lower than 21o C Nice temperature reservation Q13 When ON timer is set the system starts woring earlier than the reserved time Q14 Is it possible to use the Nice temperature reservati...

Page 81: ...tc If there is a difference adjust the preset temperature to obtain the optimum room temperature A23 After the power is turned on when the heating or dehumidifying operation is set the unit performs heat running operation for 1 minute In the heating operation the operation lamp blinks for this period It is not a malfunction A18 The reserved time may have been passed When the present time reaches t...

Page 82: ...o 155 170V in reference to the ground level 2 Also mote that it takes about 10 minutes until the voltage fall after the power switch is turned off Across a b 0V line Across a ground Across b 0V line ground approx 311 260V approx 1311V approx 311V When using an oscilloscope never ground it Don t forget that high voltages as noted above may apply to the oscilloscope Always keep your hands and metall...

Page 83: ...rminals provided for this purpose Continue discharging for more than 15 seconds CUTTING OFF POWER SUPPLIED TO THE POWER CIRCUIT Remove the receptacle of the gray brown lead wire connected to the smoothing capacitor from control P W B before performing operation check of each point in the circuit When checking conductivity at each point of circuit in electrical parts of outdoor unit to prevent seco...

Page 84: ... 93 Be sure to replace the rainproof cover after checking rainwater would enter if it is not installed R inproof cover transparent ...

Page 85: ...eck the outdoor electrical parts Timer lamp Dehumidifying lamp No No Yes Yes No Is approx 35V DC being generated Is the polarity correct Remove the outdoor unit cover and electrical parts cover and check self diagnosis lamp LD301 Does LD301 blink one time Repeats 0 25 second on and 2 second off Check to see whether the F cable is connected incorrectly or disconnected Set the service switch on the ...

Page 86: ...401 is incorrect 1 Reversing valve defective 2 Heat exchanger thermistor disconnected only in the heating mode Electrical parts in the outdoor unit 1 Indoor unit interface circuit 2 Outdoor unit interface circuit 1 Indoor unit fan motor 2 Outdoor unit electrical components For details operate again using remote controller and check from self diagnosis display of outdoor unit 1 Indoor unit fan lock...

Page 87: ...itch Does the operation starts about 1 min or more LD 303 lights is mormal Yes Normal 3 Check the Refrigerating cycle Check the electrical parts in the condensing unit No Remove the compressor Connecting connector Compressor connecting connector Compressor terminal board and self diagnosis lamp MODEL RAC 25CNH11 2 Outdoor unit judging between electrical parts of the condensing unit and refrigerati...

Page 88: ...PROTECT THE COMPRESSOR IN THE OVERLOAD CONDITION ONLY BLINKS WHEN LOW FREQUENCY SYNC STARTS IN THE FORCED COOLING OPERATION INDOOR THERMOSTAT OFF MAIN OPERATION OFF WHEN STOPPED WITH POWER RESET NORMAL WHEN POWER HAS BEEN TURNED ON 1POWER MODULE 2COMP RESSOR 3CONTROL P W B DRIVE CIRCUIT POSITION DETECTION CIRCUIT ETC 1POWER MODULE 2COMP RESSOR 3CONTROL P W B DRIVE CIRCUIT POSITION DETECTION CIRCUI...

Page 89: ...there is no abnormality such as a pattern short on the P W B heating of parts etc and replace REG2 Check the reset circuit and repair defective parts Replace the micro computer and oscillator Correct the lead wires connection of the connector Is a AC 220V voltage generated between terminals A and B of the terminal board in the outdoor unit Is a DC 35V voltage generated between terminals C and D of...

Page 90: ... after it is lit Perform a final check of operation Check the electrical parts in the out door unit and repair defective parts Check the electrical parts in the out door unit and repair defective parts around the outdoor interface trans mitting circuit Check the indoor interface transmit ting circuit and repair defective parts Check the electrical parts in the out door unit and repair defective pa...

Page 91: ...hen operation mode 57 Is a voltage of DC 5V generated be tween pins Blue and Yellow of CN10 Is the resistance between L901 ter minals Ω or less Replace the indoor unit fan motor Check whether the P W B pattern is shorted and replace REG2 Replace Q903 Replace Q903 Replace L901 Replace Q904 Replace Q904 Replace the micro computer Replace the micro computer Perform a final check of operation Perform ...

Page 92: ...otor Replace REG1 Perform a final check of operation Operate in FAN mode with HI fan speed Operation lamp lights once then goes off 5 or 10 seconds later Remove CN10 and operate in the FAN mode gain Operation lamp lights once then goes off 5 or 10 second after Is it possible to turn indoor fan by hand easily turn power switch off before checking Replace indoor fan Check if pattern of P W B is not ...

Page 93: ...remote control switch within 15 cm of the radio and press the Start Stop switch Does the radio buzz noisily Check the remote control signal receiving P W B If it is good check the main P W B Install the battery in the right polarity Replace the battery Check the LED D1 with a multimeter Check functions again If it does not work replace the remote control switch AM radio Buzz Within 15 cm ...

Page 94: ...ible area should flash in orange when you operate the remote control unit if is good 3 2 1 3 3 3 You can check the remote control switch by other methods as explained below 1 Using a video monitor Connect a video camera to a TV and aim at the remote control switch If infrared rays are emitted from the switch you will see a flash in violet on the monitor screen 2 Using a Checker You can make a chec...

Page 95: ...cuit normal Refer to the power circuit for detals Is 35V being applied between C and D Because of reverse connection of C D line chattering occurs at I F re lay Correct connection of C D line Be careful since the other parts could also be defective hen the 15A fuse is blown Mainly diode stack smoothing capacitor power modure etc Replace defective parts MODEL RAC 25CNH11 Checking the electical part...

Page 96: ... reactor diode smoothing capacitor etc connected correctly Securely insert them if loosened or disconnected Is power circuit of compressor normal Refer to Power circuit for details Is DC 35V output at C and D termi nals DC 33V 40V is output in the normal state LD301 Blinking 10 times Half voltage error Replace defective parts If 3A fuse has been blown Q1 switching transformer ZD3 etc may be defect...

Page 97: ...2V applied to both ends of the control side coil terminals of the interface relay Replace the interface relay Is a voltage 10V or more generat ed between the connection termi nals of the interface relay Check the interface circuit YES There are defective parts between the 12V output of the switching power supply on the control P W B and the interface relay Also check the solder touch etc ...

Page 98: ...he thermistor circuit normal Replace parts in the thermistor circuit Replace the thermistor Connect the thermistor connector Replace defective parts Replace the power module Perform continuity check of the leads and pattern according to the P W B diagram and circuit dia gram Perform continuity check of the leads and pattern according to the P W B diagram and circuit diagram LD301 Blinks 8 times Ac...

Page 99: ...r circuit normal Leakage of refrigerant or compressor defective Replace the control P W B Is the power module normal Are position detection circuit and drive circuit PS HIC normal Replace parts in the thermistor circuit Replace defective parts Check the continuity of replaced parts Replace the power module Replace defective parts Perform continuity check of the leads and pattern according to the P...

Page 100: ... normal Is the drive circuit normal Replace the power module Replace defective parts Replace defective parts Replace defective parts Operate the air conditioner again Does it operate normally Perform a final check of operation Is the reset circuit normal Pin 17 of the micro computer is approx 5V in the normal state ...

Page 101: ...SE EMITER COLECTER MODEL MP 6501 Circuit diagram of the device excepting the reflux diode Bu U V W Bv Bv Bw Bw Bu POWER MODULE P W B Circuit diagram of the module Terminals symbol mark of the module See next page for measuring value using tester ...

Page 102: ...t in battery is set in reverse direction and _ terminals are reversed If inner circuit of 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 phases If indicator swings the same way at ...

Page 103: ...an 4kg cm2 G When the self diagnosis lamp lights in 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 Perform a final check of operation Normal 0 39 0 98MPaG 4 10kg cm2 G Blinking Lit Lighting mode Self diagnosis lamp RAC 163CNHZ LD301 LD302 Time until the lamp lights...

Page 104: ... 113 PARTS LIST AND DIAGRAM MODEL RAS 25CNH11 11 2 18 8 20 19 12 63 1 4 60 3 7 14 15 6 5 16 13 88 61 17 9 62 10 ...

Page 105: ...AS 25CNH2 011 1 FRONT COVER ASS Y 12 PMRAS 25CNH2 012 1 MOUNTING PLATE 13 PMRAS 25CNH2 013 1 REMOTE CONTROL 14 PMRAS 25CNH2 014 3 EVAPORATOR 15 PMRAS 25CNH2 015 3 UNION 2 16 PMRAS 5100C 017 1 UNION 3 17 PMRAS 25CNH2 016 1 STEP MOTOR 60 PMRAS 25CNH2 017 1 REMOTE CONTROL HOLDER 61 PMRAS 25CNH2 018 1 FILTER 62 PMRAS 25CNH2 019 2 CAP 63 PMRAS 25CNH2 020 1 PIPE SUPPORT 18 PMRAS 07CH2 006 3 TERMINAL BOA...

Page 106: ... 115 MODEL RAC 25CNH11 55 22 59 16 26 24 23 20 21 19 13 52 58 53 56 57 2 3 51 15 14 18 4 5 9 6 8 54 17 7 11 10 12 25 ...

Page 107: ... 904 1 2S VALVE 18 PMRAC 05CV 914 1 3S VALVE 51 PMRAC 07CHV1 920 1 REVERSING VALVE 52 PMRAC 07CHV1 921 1 COIL REVERSING VALVE 53 PMRAC 07CHV1 922 1 CHECK VALVE 54 PMRAC 25CNH2 906 1 BASE 55 PMRAC 25CNH2 907 1 SILENT COVER 56 PMRAC 25CNH2 908 1 THERMISTOR OH 57 PMRAC 25CNH2 909 1 THERMISTOR OH SUPPORT 58 PMRAC 25CNH2 910 1 THERMISTOR 59 PMRAC 25CNH2 911 1 THERMISTOR SUPPORT 19 PMRAC 25CNH11 903 1 S...

Page 108: ...RAS 25CNH11 RAC 25CNH11 PM NO 0164E Printed in Malaysia HITACHI ...

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Hitachi RAC-25CNH11, Service Manual

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