Hitachi Summit RAC-18YH6 Service Manual Download Page 41

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– 39 –

33ms.
1 frame

4.95ms.
Transmit/receive
switching time

35V

35V DC line

Fig. 2-3 Voltages Waveforms of Indoor / Outdoor Microcomputers (Indoor to Outdoor Communications)

Outdoor microcomputer Pin 48

Pin 51

Indoor microcomputer Pin 50

Pin 49

33ms.
1 frame

100ms.
Leader

35V DC line

35V

Outdoor microcomputer Pin 48

Pin 51

Indoor microcomputer Pin 50

Pin 49

Fig. 2-2 Voltages Waveforms of Indoor / Outdoor Microcomputers (Outdoor to Indoor Communications)

Summary of Contents for Summit RAC-18YH6

Page 1: ...NAL DIAGRAM 15 MAIN PARTS COMPONENT 17 WIRING DIAGRAM 19 CIRCUIT DIAGRAM 20 RAS 18FH6 RAC 18YH6 RAS 25FH6 RAC 25YH6 RAC 18YH6 RAC 25YH6 COOLING HEATING INDOOR UNIT OUTDOOR UNIT INDOOR UNIT OUTDOOR UNIT 1 PHASE 50 Hz 220 230V 550 155 1 010 2 95 2 81 2 00 0 90 2 50 6 820 3 070 8 530 580 115 970 2 93 2 81 2 50 0 90 3 20 8 530 3 070 10 920 505 27 780 280 220 9 5 505 27 1 PHASE 50 Hz 220 230V 700 155 1...

Page 2: ...nd measuring instruments for use in repairs or inspection should 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 t...

Page 3: ...of parts Even rejected goods should be handled in the same way Fig 1 Conductive Container IC A conductive polyvinyl bag IC Conductive sponge 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 w...

Page 4: ...or some others be careful not to have the test probes of the measuring instrument shortcircuit a load circuit or the like Bare copper wire for body earth Working table Resistor of 1 M 1 2W Earth wire Fig 3 Grounding of the working table Metal plate of aluminium stainless steel etc Staple Screw stop at the screwed part using a rag plate Soldering iron Grounding wire Fig 4 Grounding a soldering iron...

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: ...ARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL 40 W NO NO NO ASC092CD 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 18YH6 RAC 25YH6 820g RAS 18FH6 RAS 25FH6 PWM DC35V NO NO NO NO NO NO NO YES NO NO NO NO YES IC Y...

Page 7: ...ion or fire PROHIBITION Do not put objects like thin rods into the panel of blower and suction side because the high speed fan inside may cause danger Do not bundle the power cable pull it put something on it heat it process it or put it between things Breakage of the power cable may result Use of a damaged cable may cause an electrical shock or a fire PROHIBITION PROHIBITION HOW TO USE 3 WARNING ...

Page 8: ...35YH6 RAC 18YH6 RAC 25YH6 OUTDOOR UNIT 5 NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT INDICATIONS TIMER LAMP Orange This lamp lights when the timer is working FILTER LAMP Green When the device is operated for a total of about 200 hours the FILTER lamp lights indicates that it is time to clean the filter The lamp goes out when the AUTO SWING button is pressed while the operation is stopped OPERATIO...

Page 9: ...r unit stops it will not restart for about 3 minutes unless you turn the power switch off and on or unplug the power cord and plug it in again This is to protect the device and does not indicate a failure If you press the FUNCTION selector button during operation the device may stop for about 3 minutes for protection 7 VARIOUS FUNCTIONS Auto Restart Control If there is a power failure operation wi...

Page 10: ...rosting will be performed about once an hour when frost forms on the heat exchange of the outdoor unit for 5 10 minutes each time During defrosting operation the operation lamp blinks in cycle of 3 seconds on and 0 5 second off The maximum time for defrosting is 20 minutes If the piping length used is longer than usual frost will likely to form 9 DEHUMIDIFYING OPERATION Use the device for dehumidi...

Page 11: ...the TEMPERATURE buttons the display indicates the setting The temperature setting and the actual room temperature may vary somewhat depending on conditions 3 As the settings are stored in memory in the remote controller you only have to press the START STOP button next time 11 Press the START STOP button Fan operation starts with a beep Press the button again to stop operation START STOP FAN OPERA...

Page 12: ...e OFF mark starts lighting instead of flashing and the RESERVED sign lights A beep occurs and the TIMER lamp lights on the indoor unit PM Example The device will turn off at 11 00p m The setting of turn off time is now complete 2 Set the turn on time with the TIMER control button AM 3 Point the signal window of the remote controller toward the indoor unit and press the RESERVE button The ON mark s...

Page 13: ... The horizontal air deflector is automatically set to the proper angle suitable for each operation The deflector can be swung up and down continuously and also set to the desired angle using the AUTO SWING button 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 CAUTION 2 Adjustment of the condi...

Page 14: ...17 2 CLEANING OF FRONT PANEL Remove the front panel and wash with clean water Wash it with a soft sponge After using neutral detergent wash thoroughly with clean water When front panel is not removed wipe it with a soft dry cloth Wipe the remote controller thoroughly with a soft dry cloth Wipe the water thoroughly If water remains at indicators or signal receiver of indoor unit it causes trouble M...

Page 15: ...s priority During sleep timer operation the fan speed sets to SILENT regardless of the preset speed The remote controller display indication will remain unchanged even with the SILENT setting TIMER PROGRAMMING SLEEP TIMER OPERATION PROHIBITION 19 REGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS EVERY EITHER HALF YEARLY OR YEARLY CONTACT YOUR SALES AGENT SHOULD YOU NEED ANY HELP 1 2 3 WARNING W...

Page 16: ...ording to room temperature changes Mist is generated as the air within the room is suddenly cooled by conditioned air Water generated during defrosting operation evaporates and steam is emitted Caused as the smells and particles of smoke food cosmetics etc present in room air become attached the unit and blown off into the room again Defrosting is underway as the heating operation is stopped the m...

Page 17: ... 15 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAS 18FH6 RAS 25FH6 INDOOR UNIT ...

Page 18: ... 16 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAC 18YH6 RAC 25YH6 OUTDOOR UNIT ...

Page 19: ... 81 1 ON 32 7 90 9 34 7 94 5 OFF 32 0 89 6 35 3 95 5 M RED BLK WHT YEL BLU 35V 5V 0V 0 5V FG MODEL NAME RATING APPLICABLE MODELS REVERSING VALVE COIL 135 Ω 20 C RAC 18YH6 25YH6 REACTOR L1 13 mH 0 224 Ω RAC 18YH6 25YH6 REACTOR L2 25 5 mH 0 37 Ω RAC 18YH6 25YH6 FILM CAPACITOR 45 µF RAC 18YH6 25YH6 RAS 18FH6 RAS 25FH6 POWER SOURCE DC 5V 35V DC 140 350V OUTPUT 25W 40W Control circuit built in BLU BLUE...

Page 20: ...NCE Ω 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 15 2M 1 40 U V W M M M WHITE YELLOW RED RAC 18YH6 RAC 25YH6 ASC092CD 800W DC 220 350 V ...

Page 21: ... 3A FUSE R 0 0 2 C 0 1 1 L 1 0 1 C 0 0 1 1 5A FUSE C 0 0 3 C 0 0 2 C 0 1 2 C 0 0 7 V S 2 C 0 1 3 C 0 0 8 L 0 0 2 V S 1 C 4 1 POWER SWITCHING SUPPLY C T 1 V S 3 SA1 L 0 0 1 S TAC K D I O D E DB1 RED BRN FRAME GRN 1 BLK WHT TERMINAL BOARD TERMINAL BOARD GRN YEL WHT BLK BRN RED L A N B C D I N D O O R U N I T I N D O O R U N I T C O N T R O L P W B C N 4 C N 3 C N 8 WHT C N 1 0 RED BLACK WHITE YELLOW...

Page 22: ... 20 CIRCUIT DIAGRAM MODEL RAS 18FH6 RAS 25FH6 RAS_AW_020 021_A2 2008 02 18 10 17 20 ...

Page 23: ... 21 RAC 18YH6 RAC 25YH6 MODEL RAS_AW_020 021_A2 11 17 06 11 18 AM 21 ...

Page 24: ... 22 RAS_AW_022_A3e 2008 02 19 16 33 22 ...

Page 25: ... 23 Silent RAS_AW_023_A3e 2008 03 06 20 58 23 ...

Page 26: ...CSTD 2400 min 1 2900 min 1 CKYMAX 2300 min 1 2700 min 1 CJKMAX 2300 min 1 2500 min 1 CBEMAX 2300 min 1 2300 min 1 CSZMAX 2200 min 1 2200 min 1 WMIN 2200 min 1 2200 min 1 CMIN 2200 min 1 2200 min 1 STARTMC 90 Seconds 90 Seconds DWNRATEW 80 80 DWNRATEC 60 60 SHIFTW 2 00 C 2 00 C SHIFTC 1 33 C 1 33 C CLMXTP 30 00 C 30 00 C YNEOF 25 00 C 25 00 C TEION 2 00 C 2 00 C TEIOF 9 00 C 9 00 C SFTDSW 1 00 C 1 ...

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Page 29: ...tra Lo fan mode if indoor temperature is lower than 18 C indoor fan will stop If indoor temperature is higher than 18 C 0 33 C fan will continue in Ultra Lo mode During Hotkeep or Defrost mode fan will continue in Ultra Lo mode 10 During Hot Dashed when room temperature reaches set temperature SFTDSW compressor speed is actual speed x DWNRATEW Table 3 Compressor speed Notes 1 See the data in Table...

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Page 32: ... CIRCUIT OPERATION MODEL RAS 18FH6 RAS 25FH6 1 Reset Circuit The reset circuit initializes the microcomputer program when power is ON or OFF Low voltage at pin 7 7 7 7 7 resets the microcomputer and Hi activates the microcomputer When power ON 5V voltage rises and reaches 4 4V pin 1 1 1 1 1 of IC521 is set to Hi At this time the microcomputer starts operation When power OFF voltage drops and reach...

Page 33: ...T T of the microcomputer After the amplitude of this signal has been set to 12Vp p by IC711 it is applied to the buzzer The piezoelectric element in the buzzer oscillates to generate the buzzer s sound Q141 L201 12V IRR VDD Fig 2 1 Fig 3 1 Buzzer circuit GND VOUT C212 C211 R212 0V 0V 0V R211 0V ZD141 R141 R611 C611 0V RECEIVER I P Microcomputer 13 BZ1 R721 12V IC711 Microcomputer Buzzer output 16 ...

Page 34: ...horizontal air defectors Fig 4 1 Rotation angle per step Time per step ms 0 0882 10 Horizontal air deflectors 4 Auto Sweep Motor Circuit Fig 4 1 shows the Auto sweep motor drive circuit the signals shown in Fig 4 2 are output from pin E E E E E H H H H H of microcomputer As the microcomputer s outputs change as shown in Fig 4 2 the coils of the auto sweep motor is excite to turn the rotor Table 4 ...

Page 35: ...he DC DC converter and the 35 V power supply from the outdoor unit to generate 12 V control power which drives the stepping motor during the operation In addition use the regulator IC 121 to generate 5 V power required for driving the micro computer and controlling fan motor If the terminal block was overheated due to a connecting cable improper connection the thermal fuse built in the terminal bl...

Page 36: ...shows the relation between the voltage at the point B and the speed Some differences will occur due to the condition of the unit The fan motor outputs the feedback pulse of the speed which is input into the pin D D D D D on the micro computer This pulse is equivalent to a frequency of 12 60 speed Example 1000 min 1 x 12 60 200 Hz The micro computer monitors the frequency and adjusts the output pul...

Page 37: ... P W B if necessary 2 DB3 L1 C023 and L2 The DB3 L1 C023 and L2 shape waveform of the input current When the current runs through the L1 is taken for I1 and the current runs through the L2 is taken for I2 as shown in Fig 1 2 I1 becomes an input current to the capacitor which peak value was crushed by the L1 and I2 becomes a resonance current which causes the LC resonance using the L2 and C023 By c...

Page 38: ... absorb electrical noise generated during operation of compressor and also absorb external noise entering from power line to protect electronic parts Be sure to connect the earth cable between the indoor unit and the outdoor unit Otherwise the noise filter circuit won t operate properly 6 SA1 and VS1 to VS3 These surge absorber and varistors absorb external power surge such as induced thunder Be s...

Page 39: ...est 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 are eliminated and is then shaped by the comparator The shaped signal is detected by diode amplified by amp and output to pin i i i i i of the indoor microcomputer Fig 2 2 shows the waveforms at each compon...

Page 40: ...0V 0V 5V R256 R214 R257 D206 IC5 1 2 4 6 R260 R261 R258 R259 R262 0V 5V 0V R263 Q204 R268 5V 6 5V 0V R803 Q801 R801 R802 C802 C801 L801 I F0V NF COIL 2 C808 L802 0V 12V Communications from indoor microcomputer to outdoor microcomputer Communications from outdoor microcomputer to indoor microcomputer Fig 2 1 Indoor Outdoor interface circuit CONTROL P W B C807 C806 35V 28 27 5 7 51 ...

Page 41: ...Indoor to Outdoor Communications Outdoor microcomputer Pin 48 Pin 51 Indoor microcomputer Pin 50 Pin 49 48 5 50 49 33ms 1 frame 100ms Leader 5V 5V 0V 5V 35V DC line 0V 5V 0V 0V 35V Outdoor microcomputer Pin 48 Pin 51 Indoor microcomputer Pin 50 Pin 49 Fig 2 2 Voltages Waveforms of Indoor Outdoor Microcomputers Outdoor to Indoor Communications 48 5 50 49 ...

Page 42: ... is all 1s 3 Communications waveforms Leader 100ms Leader 100ms When reset approx 100ms When reset approx 10ms 35 V 34 V 36 V 0 7 0 7 7 7 0 33 3ms 3 2 1 NO 0 Bit No 0 7 0 7 0 7 0 7 Bit No 0 3 2 1 33 3ms 33 3ms 33 3ms Transmit receive switching time 4 95ms 33 3ms 33 3ms Outdoor message Indoor message 33 3ms 33 3ms 0 Character No 2 In n door microcomputer to outdoor microcomputer HIC ...

Page 43: ...e 0 LSB Actual compressor rotation speed 0 LSB Compressor command speed 0 LSB Compressor minimum rotation speed 0 LSB Compressor minimum rotation speed 1 Compressor minimum rotation speed 2 Compressor minimum rotation speed 3 Compressor minimum rotation speed 4 MSB Compressor command speed 1 Compressor command speed 2 Compressor command speed 3 Compressor command speed 4 Compressor command speed 5...

Page 44: ...ower module circuit U is ON V is ON 3 Intelligent power module circuit IPM circuit Fig 3 1 shows peripheral circuits of intelligent power module IPM In the diagram U V and W are called the upper arm U V and W the lower arm ...

Page 45: ...trolled to ON OFF by 2 5kHz 5kHz chopper signal Rotation speed of the compressor is 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 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 choppe...

Page 46: ...tent waveform as shown in Fig 3 3 Since current at point B is approximately proportional to the input current of the air conditioner input current is controlled by using DC current Id detection resistor Reference If power module is defected self diagnosis lamps on the MAIN P W B may indicate as shown below LD303 LD302 LD301 MAIN P W B SERVICE SWITCH HIC IPM Fig 3 5 Table 3 1 ...

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Page 49: ...supply for microcomputer peripheral circuits and IPM driver circuit and as well as DC 35V are produced by switching power circuit Switching power circuit performs voltage conversion effectively by switching transistor IC1 to convert DC 330V voltage to high frequency of about 20kHz to 200kHz Fig 5 1 AC220 230V ...

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Page 53: ...put of this room air conditioner system through the current sensor CT1 in order to keep the maximum rating of components by reading total operating current ID OVL is watching and limits the compressor current through the detection resistor which is built in IPM in order to control the compressor reliability Since the compressor reliability is related with its speed the ID OVL value is also linked ...

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Page 55: ... current R247 R248 R249 are provided to perform the same overload judgement even when the voltage varies 3 Start current control It is required to maintain the start current DC current constant to smooth the start of the DC motor of the compressor RAC 18YH6 RAC 25YH6 uses software to control the start current The start current varies when the supply voltage varies This control method copes with va...

Page 56: ...he reset circuit initializes the microcomputer program when Power is ON from OFF Low voltage at pin 7 resets the microcomputer and HI activates the microcomputer Fig 6 10 shows the reset circuit and Fig 6 11 shows waveform at each point when power is turned on and off When power is turned on 12V line and 5V line voltages rise and 12V line voltage reaches 10 9V an reset voltage input to pin 7 of mi...

Page 57: ...rost 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 w of microcomputer drops If this voltage becomes lower than the set value stored inside the microcomputer starts defrosting control During defrosting operation the microcomputer transfers the defrosting condition command to ...

Page 58: ...ormally ON close Table 6 3 shows the circuit operation of each operation mode If the following result is not obtained reversing valve control circuit may be defective Table 6 3 Point Operation mode Cooling In normal cooling operation In normal heating operation In defrosting operation approx 35 V approx 35 V 0V Hi 0V Hi 12V Lo 0V not fixed Heating Between Pin 29 of microcomputer and 0V Between Pin...

Page 59: ... open close direction is as shown below When the power is turned on approx 0 9 V is applied to CN15 pins 1 to 4 when no power is supplied approx 12 V is applied When the power is reset expansion valve performs initial operation for 5 to 10 seconds During initial operation measure pins 1 to 4 of CN15 using multimeter If no change is found around 0 9 V or 12V expansion valve or microcomputer is defe...

Page 60: ...se width FG feedback Slower Instruction Faster Increase pulse width FG pulse is also used for Fan Motor failure detection Microcomputer will monitor FG pulse 30 seconds after start the fan motor If there is no signal detected it will consider that the Fan Motor was malfunction and stop the operation In this case LD302 on main R107 and IC4 are used for Fan Motor over current Vsp high Faster Vsp low...

Page 61: ... growing 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 cause in Fan Motor problem or control board problem Stop after the Fan motor runs 2 minutes Fan Motor may be broken Caution Plea...

Page 62: ...anges from HIGH through MED to LOW while the temperature is preset at 30 Check if the indoor heat exchanger is frosted 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 It occurs during defrost ing Wait for 5 10 minutes until the condenser is defrosted At the beginning of heating the fan speed remains LOW for 3...

Page 63: ... 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 64: ...djust the temperature within a range of 3 C by pressing the Room Temperature button If the temperature is 1 C higher than the auto preset temperature 1 C will appear If the temperature is 1 C lower than the auto preset temperature 1 C will appear heard when operation is started When operation is started the compressor rotation speed goes to maximum to increase the heating or cooling capability so ...

Page 65: ...er ground it Donít forget that high voltage as noted in the figure above may apply to the oscilloscope Remember that voltage of 175 V is applied to the 0V line on the P W B or the like as shown in the right diagram Indoor Controller Outdoor Controller Power Switch Point 400 F I P M Compressor motor Point line Control P W B Main P W B Voltage at point A Ground voltage Grounding 350V Point B 0V line...

Page 66: ...tinuity check for each circuit part of the outdoor unit be sure to discharge the smoothing capacitors Discharge Procedure 1 Turn off the power of the indoor unit or pull out the power supply plug 2 After power is turned off wait for 10 minutes or more Then remove electrical parts cover and apply soldering iron of 30 to 75 W for 15 seconds or more to TAB05 and R001 terminals on the main P W B as sh...

Page 67: ...se caution not to pinch any code between the part and cabinet Removing electrical parts 1 Remove the electrical parts cover 2 Remove the connectors from the CN1 heat exchange thermistor CN4 stepping motor and CN10 fan motor 3 Remove two lock screws 4 Remove the electrical parts in the direction of arrow Removing control P W B 1 Remove the connectors from the CN2 and CN3 2 Remove the P W B from the...

Page 68: ... fingers to unlock and remove the connector 3 When checking the voltage and waveform do not connect the probes to the forbidden areas show below Touching them may cause the ICP1 blowout and Q111 failure The Q111 is a MOS FET and its gate terminal is a high impedance When a probe such as a multimeter is contacted with the gate G the Q111 may have the continuous ON state to supply overcurrent in the...

Page 69: ...as been performed several times Note In some failure modes only the retry operation is repeated without lamp indication Failure modes that will repeat a retry operation without the indoor unit lamp indication are as follows OH thermistor temperature rise Outdoor unit communication error Power voltage abnormal Less frequent defects The LD301 indicates a mode of failure detected on the outdoor unit ...

Page 70: ... 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 Outdoor unit electrical components For details operate again using remote comtroller and check from self diagnosis display of outdoor unit interface circuit 1 Room thermist...

Page 71: ... 69 SELF DIAGNOSIS LIGHTING MODE MODEL RAC 18YH6 RAC 25YH6 SELF DIAGNOSIS LIGHTING MODE MODEL RAC E10H2 ...

Page 72: ...k outdoor electrical parts Check the refrigerating cycle Normal No Yes Check the drive circuit IPM using the PRD checker Check the position sensor circuit With the unit set in the operating state press the start stop button Does the unit operate for approximately 2 seconds the LD303 coming on and then stop due to a failure of switching the lamp blinking 4 times OUTDOOR UNIT LD303 LD302 LD301 MAIN ...

Page 73: ...tdoor unit and observe the self diagnosis lamp LD301 Count how many times the lamp blinks Blinks other than 1 time Blinks 1 time Can the unit be operated using the outdoor unit service switch See the nameplate on the outdoor unit for operating instructions Check the outdoor electrical parts Check the indoor electrical parts Check the refrigerating cycle In the event of overload limit cut or OH the...

Page 74: ...r outdoor unit connection cable and correct any defective section wrong connection incomplete insertion Is AC220 230V being generated between terminals A and B on the outdoor unit terminal board Is DC35V or 20V being generated between terminals C and D on the indoor unit terminal board Is the microcomputer reset input pin7 Hi Is the microcomputer clock signal 10MHz at pins 0 and A being generated ...

Page 75: ...mputer Perform final operation check 3 Air deflector does not move others are normal Are pulse signals output at microcomputer pins when auto swing is turned on in the fan mode Replace the microcomputer Is a voltage over 15 or below 10V being generated on the 12V line Replace IC111 Yes Yes Yes Yes No No No No Check IC711 If it is normal replace the air deflector motor Perform final operation check...

Page 76: ...the terminal board Insert the connection cable securely Replace IC121 Check if a short occurs in the 5V line If the 5V line is shorted ICP1 will be open again Check to see if the connection cables are disconnected or reversed If normal check the outdoor unit P W B Has the terminal board thermal fuse blown open Replace Q111 and IC111 Is DC5V being generated Perform final operation check When the un...

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Page 78: ... also be defective Replace defective parts Is the power circuit normal See the description on power circuit for details Is the switching power circuit OK Has the 3A fuse blown Check to see if C and D cables are connected correctly If reversed or incompletely inserted correct the cable connection Replace any defective parts If the 3A fuse has blown the varistor 2 etc may also be defective With the ...

Page 79: ...rs after the fan operates for 2 minutes Is the voltage between 4 and 6 at CN24 normal Normally the voltage is above approx DC1 7V Connect the connector Remove any obstructions Replace the fan motor and main P W B Is the voltage between 4 and 7 at CN24 normal Check to see if the voltage is within 2 5V 0 5V using a tester In effect the output voltage is alternately switched between 5V and 0V Replace...

Page 80: ...t terminals A and B on the terminal board Apply AC220 230V Check the interior wiring TAB05 TAB11 reactor and C023 yellow green connected properly Connect properly Replace the main P W B Possible causes include Power relay malfunction Defective microcomputer terminal Yes Yes Yes No No No ...

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Page 84: ...in P W B LD301 blinks 1 time Reset stop However the unit always resets and stops just after power is supplied this does not indicate a fault Is the reset circuit normal Normally pin 7 of CN18 is approx 5V Replace the main P W B Make sure again that connectors are connected securely Perform final operation check Yes Yes Yes No No ...

Page 85: ...gn and a beep COOLING is indicated HEATING is indicated NOTE 1 The indication of the changed shift value and symbol of COOLING or HEATING will disappear after 10 seconds 2 The changed shift value will remain unchanged after turned off the power 3 When 0 is indicated the shift value is at the initial setting 5 Press START STOP button to complete the shift value changing procedure PROCEDURE 1 PROCED...

Page 86: ...ive 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 malfunctioning part LD301 Self diagnosis lamp Lighting ...

Page 87: ... times Be sure to push the service switch for a second again to stop the forced cool operation HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY 1 Connect the large dia pipe side and small dia pipe side service valve using a pipe Parts to be prepared 1 Reducing union 2 8 6 35 mm 3 8 9 52 mm 2 Copper pipe 2 8 and 3 8 Connect the small diameter service value and the large diameter service valve using th...

Page 88: ...ext page for measuring value using multimeter PS21564 C Circuit of 1 device Gate Collector Emitter Internal circuit diagram of module Terminal symbols of power module Model IPM Intelligent Power Module DIAGNOSIS ...

Page 89: ...is performed it is normal When a digital multimeter is used and terminals will be reversed since the orientation of built in battery is inverted Note If internal circuit of power module is disconnected open and pointer of the mutimeter does not swing it may be assumed to be normal If the pointer swings when and terminals are connected in reverse it is normal Compare swing statuses for U V and W ph...

Page 90: ... the front cover forward and release the claws 2 Hold the front cover at both lower sides and pull them forward to remove Fig 3 Indicating P W B Control P W B Support hook 3 Control P W B and Indicating P W B 1 Remove each connector from the lead wire 2 Remove the four P W B supports from the control P W B 3 Pull the support hook at the upper side of the indication lamp of the indicating P W B and...

Page 91: ...ing screws 2 locations and radiation fin fixing screws 5 locations and remove the P W B from the support 1 Electrical Parts 1 Remove the upper cover fixing screws and lift the cover to remove it 2 Remove the service valve cover 3 Remove the terminal plate cover 4 Remove the right side cover 3 Remove the screws from the upper and lowerbearing covers 4 Remove the locking hook of the lower bearingcov...

Page 92: ... 90 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAS 18FH6 RAS 25FH6 ...

Page 93: ...MBLY 19 HWRAS 25YH4 A20 1 POWER SWITCH 21 HWRAS 25YH4 A22 1 P W B INDICATION 22 HWRAS 25YH4 A23 1 CONNECTING CORD 12P 23 HWRAS 25YH4 A24 1 ELECTRIC PARTS COVER 24 HWRAS 25YH4 A25 1 COVER TERMINAL 25 HWRAS 25YH5 A07 1 DRAIN PAN 26 HWRAS 25YH5 A08 1 HORIZONTAL DEFLECTOR 27 HWRAS 25YH4 A28 2 DEFLECTOR SUPPORT 28 HWRAS 25YH4 A29 1 AUTO SWEEP MOTOR 29 HWRAS 25YH4 A30 1 DRAIN CAP 30 HWRAS 25YH4 A31 1 HE...

Page 94: ... 92 OUTDOOR UNIT MODEL RAC 18YH6 RAC 25YH6 2 19 18 50 4 3 6 17 20 12 16 8 13 14 7 35 36 39 25 33 30 40 38 35 29 41 51 39 36 46 44 37 27 45 32 31 47 42 10 5 9 43 1 24 23 22 21 28 ...

Page 95: ...WRAC E10H2 A18 1 SIDE COVER L HWRAC E10H2 A19 1 1 FRONT COVER HWRAC E10H2 A21 1 DISCHARGE GRILL HWRAC 25YH4 A32 2 ELECTRIC PARTS PLATE 1 ELECTRIC PARTS COVER HWRAC E08H A11 1 TERMINAL PLATE HWRAC D10EX2 A09 1 TERMINAL BOARD 2P HWRAC 25YH4 A37 3 HEAT SINK REGURATOR1 1 1 FUSE 15A HWRAC 25YH4 A41 1 FUSE 3A HWRAC 25YH4 A42 1 VARISTOR 1 P W B MAIN HWRAC E10H2 A25 1 FUSE 1A HWRAC E10H2 A26 1 SUPPORT P W...

Page 96: ...HITACHI AW NO 0024E RAS 18FH6 RAC 18YH6 RAS 25FH6 RAC 25YH6 ...

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Hitachi Summit RAC-18YH6, Service Manual, Page: 41 / 96

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