Hitachi RAC-50DH7 Service Manual Download Page 54

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Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with
each other.

Indoor P.W.B.

Outdoor P.W.B.

Terminal board

D101

I/F 0V

C821

R821

C822

I/F 0V

IF transmit
output (SDO)

IF receive
input (SDI)

Micro
computer

12V

IC8

R283

Q201

HIC

R813

R812

C802

Q803

C804

R811

R810

SDO1

SDI1

L801

L811

C801

R802 Q801

R801

R803

D210

C805

NF COIL2

C802

C216

R263

R262

R261

R260

D206

C214

Q206

R254

R255

R258

R257

R256

R259

C803

C804

Interface
relay

35V

(Communications from indoor micro computer to outdoor micro computer)

(Communications from outdoor micro computer to indoor micro computer)

Fig. 2-1 Indoor / Outdoor interface Circuit

Summary of Contents for RAC-50DH7

Page 1: ...After installation RAC 50DH7 RAC 60DH7 RAC 70DH7 W A kW B T U h W A kW B T U h W H D kg DUCTING TYPE TYPE MODEL POWER SOURCE TOTAL INPUT TOTAL AMPERES CAPACITY TOTAL INPUT TOTAL AMPERES CAPACITY DIMENSIONS mm NET WEIGHT COOLING HEATING OUTDOOR UNIT RAC 50DH7 INDOOR UNIT RAD 50DH7A 900 270 720 35 1 Ø 50 Hz 220 240V 1 400 200 2 100 6 40 5 90 5 00 0 90 6 00 17 070 3 073 20 490 1 590 200 2 200 7 30 6 ...

Page 2: ...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 3: ...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 Staple...

Page 4: ...n and re start in a moment there is occasion 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...

Page 5: ...PORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL RAD 50DH7A RAD 60DH7A RAD 70DH7A 56 W NO NO NO NO NO 3 15A G4A NO NO NO NO 416NR NO YES IC YES NO NO JU1015D4 NO NO YES NO NO NO NO NO NO NO NO YES IC NO 30 A TIME DELAY FUSE 1800g UNIT REFRIGERANT CHARGING VOLUME Refrigerant R410A PIPES MAX 30m PIPES MIN 5m RAC 50DH7 RAC 60DH7 RAC 70...

Page 6: ...k CAUTION Discharge grille and suction grille shall be cover by insulation material to prevent water drop The indoor piping should be insulated with the enclosed insulation pipe If the insulator is insufficient please use commercial products Be sure to completely seal any gap with putty Drain pipe Must be installed separately Insulate indoor part of pipe to prevent condensation The difference in h...

Page 7: ...TH mm MODEL HEIGHT mm DEPTH mm MODEL NAME AND DIMENSIONS OUTDOOR UNIT DRAIN PIPE Condensed water drain to outside CONNECTING CORD AIR INLET BACK LEFT SIDE AIR OUTLET RAD 50DH7A RAD 60DH7A RAD 70DH7A RAC 50DH7 RAC 60DH7 RAC 70DH7 900 850 270 800 720 298 ...

Page 8: ...Supply Companies are to be observed Minimum Maximum Minimum Maximum Indoor Dry bulb C 21 32 20 27 Wet bulb C 15 23 12 19 Outdoor Dry bulb C 21 43 2 21 Wet bulb C 15 26 1 15 Note Avoid to use the room air conditioner for cooling operation when the outside temperature is below 21 C 70 F The recommended maximum and minimum operating temperatures of the hot and cold sides should be as below Cooling He...

Page 9: ... 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 arises like burning smell please stop operating the unit an...

Page 10: ...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 11: ...T This button allows selecting the optimal or preferred fan speed for each operation mode Precautions for Use Do not put the remote controller in the following places Under direct sunlight In the vicinity of a heater Handle the remote controller carefully Do not drop it on the floor and protect it from water Once the outdoor unit stops it will not restart for about 3 minutes unless you turn the po...

Page 12: ...ted when the power is resumed with previous operation mode As the operation is not stopped by remote controller If you intend not to continue the operation when the power is resumed switch off the power supply When you switch on the circuit breaker the operation will be automatically restarted with previous operation mode Note 1 If you do not require Auto Restart Control please consult your sales ...

Page 13: ... and varies to MED 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 SILENT Fan speed ultra slower Set the desired room temperature with the TEMPERATURE buttons the display indicates the setting The temperature setting and the actual room temperature may var...

Page 14: ...ature regardless of the 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 oper...

Page 15: ...n speed slower SILENT Fan speed ultra 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 s...

Page 16: ...essing the ON Button At the beginning of setting time 6 hours was set Setting time will change according to the below sequence The value change quicker if you keep pressing the button ON Timer Reservation 0 5 1 0 1 5 9 5 10 11 12 0 5 hour interval 1 hour interval 1 Press the Cancel button As the time settings are stored in remote controller memory you only have to press the Reserve button in order...

Page 17: ...he device will continue working for the designated number of hours and then turn off Press the SLEEP button indoor unit will produce a beep The timer information will be displayed on the remote controller How to Cancel Reservation Press the CANCEL button The RESERVED sign goes out with a beep Example Setting 3 hours sleep time Hr ...

Page 18: ...health If you set the sleep timer after the off or on timer has been set the sleep timer becomes effective instead of the off or 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 19: ...ervals the doors and windows should be opened to let fresh air in Make sure the room is ventilated when operating the air conditioner at the same time as other heating appliances 3 Using the timer is recommended before going to sleep or going out 4 The following must never be used for cleaning the indoor and outdoor units Benzine thinner and scrub can damage plastic surfaces or coating Hot water a...

Page 20: ...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 21: ...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 22: ...e indoor unit Unit failure may result When cleaning the heat exchanger with a vacuum cleaner make sure to wear gloves so as not to injure your hands on the heat exchanger fins CAUTION 1 AIR FILTER CAUTION Do not wash 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...

Page 23: ...mperature suitable CONDITION CHECK THE FOLLOWING POINTS Notes In quiet or stop operation 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 ai...

Page 24: ...narrow and wide dia pipes 3 Piping length is within 20m 4 Height different of the piping between the indoor unit and the outdoor unit should be within 10m 5 Power supply cord length is about 2m 6 Connecting cable 2 5mm dia x 3 AB Line 1 6mm dia x 2 CD Line is used for the connection D C B A L N D C B A Indoor Unit Outdoor Unit Connecting Cord Power supply cord MODEL RAD 50DH7A RAD 60DH7A RAD 70DH7...

Page 25: ...efrigerant Gas Pipe Connection Refrigerant Liquid Pipe Connection AIR FLOW DIRECTION AIR FLOW DIRECTION 20 1 90 90 20 1 10 10 9 4 100 100 6 Ø7 6 Ø7 6 Ø7 6 Ø7 300 10 300 102 2 20 30 720 22 20 40 900 980 for Suspension Bot 300 300 107 2 10 30 22 676 Drain Pipe Connection for Suspension Bolt ...

Page 26: ... grille 168 74 26 850 957 81 800 96 169 5 788 10 10 10 320 340 Air outlet 340 20 22 298 201 Handle Holes for anchor bolt 2 ø12 Fixing hole 507 198 57 12 37 Notch for anchor bolt 2 ø12 Notchs More than More than More than 100 More than 700 100 100 Service space ...

Page 27: ...AT ON 15 6 60 1 20 0 68 0 OFF 15 3 59 5 20 7 69 3 ON 23 6 74 5 28 0 82 4 OFF 23 3 73 9 28 7 83 7 ON 31 6 88 9 36 0 96 8 OFF 31 3 88 3 36 7 98 1 M RED BLK WHT YEL BLU 280V 15V 0V 0 6 5V FG MODEL RAD 50DH7A RAD 60DH7A RAD 70DH7A POWER SOURCE DC 280V DC350V OUTPUT 56W 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 R...

Page 28: ...lant check the color of the refrigerant oil inside the compressor If the color has been changed conspicuously replace the compressor V R YELLOW W S RED U C WHITE MODEL COMPRESSOR MODEL PHASE SINGLE RATED VOLTAGE AC 220 240 V RATED FREQUENCY 50 Hz POLE NUMBER 4 CONNECTION 20 C 68 F 75 C 167 F RESISTANCE VALUE RAC 50DH7 RAC 60DH7 RAC 70DH7 JU1015D4 2M 1 05 U V W WHITE YELLOW RED 2M 1 268 ...

Page 29: ... UNIT Option part 1102 1101 WIRING DIAGRAM MODEL RAD 50DH7A RAD 60DH7A RAD 70DH7A RAC 50DH7 RAC 60DH7 RAC 70DH7 BLU BLUE YEL YELLOW BRN BROWN WHT WHITE GRY GRAY ORN ORANGE GRN GREEN RED RED BLK BLACK PNK PINK VIO VIOLET IVO IVORY ...

Page 30: ... 29 CIRCUIT DIAGRAM Wired Remote Control ...

Page 31: ... 31 CIRCUIT DIAGRAM MODEL RAD 50DH7A RAD 60DH7A RAD 70DH7A ...

Page 32: ... 33 CIRCUIT DIAGRAM MODEL RAC 50DH7 RAC 60DH7 RAC 70DH7 ...

Page 33: ...otor Wired remote control receiver circuit Wired remote control Room temperature thermistor Heat exchanger thermistor Static pressure select switch Drain pump test switch Temporary switch Initial setting circuit Reset circuit H link Indoor microcomputer AX 7X20 Buzzer circuit Indicating lamp Operation Timer Power circuit Indoor Outdoor interface circuit Indoor fan motor DC fan motor drive circuit ...

Page 34: ...MAX 5200 min 1 CSTD 5000 min 1 WMIN 1500 min 1 CMIN 1600 min 1 STARTMC 60 Seconds DWNRATEW 100 DWNRATEC 100 SHIFTW 2 00 C SHIFTC 1 00 C CLMXTP 30 00 C YNEOF 20 00 C TEION 0 00 C TEIOF 9 00 C SFTDSW 2 00 C DFTIM1 60 Minutes DFTIM2 60 Minutes RAD 50DH7A RAD 70DH7A RAD 60DH7A 5800 min 1 ...

Page 35: ... 39 51 53 53 55 57 49 29 66 Heating ...

Page 36: ...trol mode 4 Compressor minimum ON time and OFF time is 3 minutes 5 During normal cooling mode compressor 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 During Cool Dashed when room temperature reaches set temperature 1 C compressor rpm is actual rpm x DWNRATEC Temperature Calculated difference...

Page 37: ... during sleep operation the set temperature when stopped as well as the time continue to be counted 5 If the set lime is changed during sleep operation all data including set temperature time etc is cleared and restarted 6 If sleep operation is canceled by the cancel key or sleep key all data is cleared Cooling Sleep Operation Compressor speed Maximum speed Indoor fan Outdoor fan Timer lamp Operat...

Page 38: ...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 39: ...lue 3 C After thermo off operation continue 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 ope...

Page 40: ...ed does not change even when the fan speed mode is changed Lo 5 When defrosting is to be set during sleep operation defrosting is engaged and sleep operation is restored after defrosting 6 When operation is stopped during sleep operation the set temperature when stopped as well as the time continue to be counted 7 If the set time is changed during sleep operation all data including set temperature...

Page 41: ...7 INDOOR UNIT OUTDOOR UNIT COOLING DEHUMIDIFYING DEFROSTING OUTDOOR UNIT HEATING INDOOR UNIT COMP S TANK 4S VALVE SILENCER 2S VALVE EXPANSION VALVE STRAINER STRAINER COND REVERSING VALVE COMP S TANK 4S VALVE 2S VALVE EXPANSION VALVE STRAINER STRAINER COND REVERSING VALVE SILENCER ...

Page 42: ...IT OUTDOOR UNIT COOLING DEHUMIDIFYING DEFROSTING OUTDOOR UNIT HEATING INDOOR UNIT COMP S TANK 5S VALVE SILENCER 2S VALVE EXPANSION VALVE STRAINER STRAINER COND REVERSING VALVE COMP S TANK 5S VALVE 2S VALVE EXPANSION VALVE STRAINER STRAINER COND REVERSING VALVE SILENCER ...

Page 43: ...ACH MODE ONE 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 ...

Page 44: ...f IC521 is set to Hi At this time the 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 RAD 50DH7A RAD 60DH7A RAD 70DH7A 1 Reset Circuit Fig 1 1 Fig 1 2 Voltage 5 0V Reset enter at 4 2V Reset release at 4 4V voltage 5 0V Voltage at pin 7 of microcomputer Voltage sup...

Page 45: ... Buzzer output BZ 12V 0V R722 Q722 30 BZ When the buzzer sounds an approx 3 9kHz square signal is output from buzzer output pin of the microcomputer 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 30 ...

Page 46: ...room temperature as shown in Fig 5 2 A 3 Initial Setting Circuit IC401 When power is supplied the microcomputer reads the data in IC401 E2 PROM and sets the preheating activation value and the rating and maximum speed of the compressor etc to their initial values Data of self diagnosis mode is stored in IC401 data will not be erased even when power is turned off Fig 3 1 Microcomputer External ROM ...

Page 47: ...temporarily when the wireless remote control is lost or faulty The air conditioner operates in the previous mode at the previously set temperature However when the power switch is set to OFF it starts automatic operation INDICATION P W B Option 5V Temporary Switch 1 Temporary Switch 2 C1 1 2 3 4 7 CN9 CN11A 5V 0V 0V 48 HA input HA output Micro computer C2 M1 M2 R601 R602 C601 R701 33 Fig 6 1 0V He...

Page 48: ... causing the drain level to rise abnormally When the float switch is activated the timer indicator will flash six times Note that the float switch will also be activated disabling operation if the connector of float switch has defective contact or is connected incompletely 0V 0V 0V 5V R621 C620 R539 Microcomputer R620 CN16 FLOAT SW Normally Hi 4 5V 53 1 2 9 Drain pump drive circuit 58 5 12 1 12V D...

Page 49: ...ltage VCC Motor Controller Power Supply VSC RPM Instruction motor WCC return the FG sinal under frequency RPM The circuit produces fan motor drive from 340V DC supplied from the indoor unit and controls the fan motor speed CAUTION 1 Indoor fan motor circuit will be connected with primary power source line and please take care of the electrical shock CAUTION 2 Please do not disconnect the fan motor...

Page 50: ...no 13 by using photo coupler PC101 L550 L551 C770 and C771 act as a filter to reduce the noise from the wired remote control 12 Static pressure switch Fuse Operate LED Timer LED Temporary sw2 High Low Normal Normal Test Static pressure sw Drain pump test drive sw Micro computer Buzzer Static pressure switch When set to High the revolution per minute will increase 100 min 1 and when set to Low the ...

Page 51: ...tive 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 it may not operate at all because no DC voltage is gener...

Page 52: ...rom power line to protect electronic parts 6 Surge absorber Varistor 1 2 3 absorbs external power surge 7 Inrush protective resistor R002 R003 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 done Be careful to avoid an electric shock as a...

Page 53: ...cuit The transmitting circuit modulates this signal by approx 38kHz high frequency This high frequency signal is amplified by a transistor superimposed on the DC 35V line via C801 or C811 C821 and L801 or L802 L803 and supplied to the indoor unit To prevent erroneous reception the outdoor microcomputer is designed so that it cannot receive a signal while is is outputting a request signal The recei...

Page 54: ...ve input SDI Micro computer 5V 5V 5V 12V 5V 5V IC8 R283 Q201 5V 5V 5V HIC 5V R813 R812 C802 Q803 C804 R811 R810 SDO1 SDI1 73 68 0V L801 L811 C801 R802 Q801 5V R801 R803 D210 0V 0V 0V 0V 0V 0V 0V C805 NF COIL2 C802 C216 R263 R262 R261 R260 D206 C214 Q206 R254 R255 R258 R257 R256 R259 C803 C804 Interface relay 35V Communications from indoor micro computer to outdoor micro computer Communications fro...

Page 55: ...5V 0V 5V 35V 35V 35V DC line Base of outdoor P W B Q801 Q802 Outdoor micro computer 69 11 Pin 68 Pin Pin SDI Pin 35V DC line 100ms Leader 33ms 1 frame 5 7 5ms Transmit receive switching time 33ms 1 frame 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 ...

Page 56: ...n the positive e side are called 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 57: ...elow Fig 3 2 Switching order of power module N 60 2 X 1 T Fig 3 3 shows voltage current 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 arm is chopper second half is ON Fig 3 3 Voltage waveform at each point When power is supplied U U because of that U is chopped current flows as shown below 1 When U transistor is ON U t...

Page 58: ...of power module simple inspection inspection mode when operated with compressor lead disconnected LD310 blinks four times about 2 seconds later Unit has not entered the normal operation Fig 3 4 System Power module circuit U is OFF V is ON Self diagnosis Self diagnosis lamp and mode lp peak current cut LD301 Abnormal low speed rotation LD301 Switching incomplete LD301 Blinks 2 times Blinks 3 times ...

Page 59: ...r circuit With this power current flows to pin 4 of IC1 via R701 and IC1 starts to turn ON Since voltage in the direction of arrow generates at point c at the same time current passing through R708 and D702 is positive fed back to IC1 2 During ON The drain current at IC1 increases linearly During this period the gate voltage and current become constant because of the saturation characteristics of ...

Page 60: ... 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 power rush prevention relay shorting in relay etc 2 REG 1 regulator is abnormal etc Shorting on primary circuits When shorting occurs in the secondary circuits there is no abnormality i...

Page 61: ...or generating reverse electromotive force according to number of rotations This reverse electromotive force is voltage divided by R503 R505 and R608 R610 and appears as point A voltage IC3 compares and digitalizes point A voltage with point B voltage in which DC voltage Vd is voltage divided by R501 R502 and R611 and inputs this to microcomputer as position detection signals for points C D and E M...

Page 62: ...201 Fig 7 1 Peripheral circuit of microcomputer AX 6V Table 7 1 Circuit block Basic operation Peak current cutoff circuit Overload external judgment circuit Voltage amplifier circuit Reset circuit This circuit detects DC current flowing power module When over current instantaneous value flows it stops upper and lower arm drive circuit and also produces lp signal to stop microcomputer This circuit ...

Page 63: ...AX 6V01 micro computer Fig 8 1 Overload Control System Configuration Fig 8 2 Overload control is to decrease the speed of the compressor and reduce the load when the load on the air conditioner increases to an overload state in order to protect the compressor electronic components and power breaker Overloads are judged by comparing the DC current level and set value Fig 8 1 shows the overload cont...

Page 64: ...line voltage reaches 7 2V Zener voltage of ZD201 ZD201 turns ON and Q211 and Q205 turn on and reset voltage becomes Hi Reset voltage is not set to Hi until VDD of microcomputer rises to 5V enabling operation due to ZD201 After power turns off when 12V line voltage drops ZD201 also turns OFF 12V line 12V line 5V line 5V line Reset voltage Reset voltage 12 6 0 Voltage when power is turned ON 12 6 0 ...

Page 65: ...stor OH overheat thermistor and electric expansion valve thermistor so that they detect the temperatures of the unit and control the system The circuit of the thermistors is shown as Fig 10 1 for model RAS 70YHA1 RAS 80YHA1 and their roles and temperature measuring points are shown as Table 10 1 Fig 10 1 Temperature Detection Circuit ...

Page 66: ...r units The temperatures are used to decide how much the expansion valve is opened Outdoor temperature is used to decide the various operations of the air conditioner CN5 DEF thermistor Heat exchanger CN6 Outdoor temperature thermistor Outside temperature CN7 Electric expansion valve thermistor NARROW PIPE Indoor unit NARROW PIPE CN8 Electric expansion valve thermistor WIDE PIPE Indoor unit WIDE P...

Page 67: ...nnections of them are checked out they are replaced If you can see two or more troubled thermistors a small number of blink takes precedence of others The electric expansions valve thermistor is put togrther with 3 pieces when replacing the thermistor replace one set of 3 pieces as taking care of positioning If you don t do so the unit may not operate normally and its cooling performance may drop ...

Page 68: ...with voltage that has not changed from around 0 9V or 12V expansion valve or microcomputer is defective Fig 11 2 shows logic waveform when expansion valve is operating 11 Electric expansion valve Pin Drive status Lear wire 1 ON OFF OFF OFF Pin No 12V 0 9V 200ms 75ms 50ms 42 38 41 37 40 36 39 35 ON ON OFF OFF ON OFF OFF ON OFF ON OFF OFF OFF ON ON OFF OFF OFF ON OFF OFF OFF ON ON OFF OFF OFF ON 2 3...

Page 69: ...ll be similar to waveform of input voltage I input current V input voltage input voltage input current Effective voltage area Effective voltage area Invalid power area Even if voltage is applied current does not flow 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 ...

Page 70: ...ntil 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 beginning of heating the ...

Page 71: ...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 72: ...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 73: ...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 things away from the enclos...

Page 74: ...eck for each part of circuit 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 sho...

Page 75: ... Room thermistor or heat exchanger thermistor is faulty When room thermistor or heat exchanger thermistor is opened circuit or short circuit DC fan motor overcurrent detection Overcurrent in indoor DC fan motor has been detected IC401 data reading fault There was error in the data read from IC401 1 Four way valve faulty 2 Disconnection in heat exchange thermistor only during heating Service SW in ...

Page 76: ... 86 SELF DIAGNOSIS LIGHTING MODE MODEL RAC 50DH7 RAC 60DH7 RAC 70DH7 ...

Page 77: ...er 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 lamp lighting mode See Troubleshooting when the timer lamp blinks Refer page 85 Is approx DC 33 to 37V being generated Is th...

Page 78: ...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 79: ... 89 2 Outdoor unit does not operate but receives remote infrared signal ...

Page 80: ...does not operate other is normal Disconnect joint connector at indoor fan motor and set to the fan mode again 4 All systems stop from several seconds to several minutes after operation is started all indicators are also off ...

Page 81: ... D Is DC 35V being output between cathode and mode of D701 Is DC 12V being supplied accross the control side coil terminal of interface relay Replace the interface relay D701 and C701 may be defective There is a defective between the 12V output of switching power supply and interface relay ...

Page 82: ... 92 CHECKING THE REMOTE CONTROLLER ...

Page 83: ...t normal See the description on power circuit for details Is 5V being generated between Pin 4 0V and pin 3 5V at CN 19 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 5A fuse blown See the self diagnosis lamp lighting mode Check to see whether the conne...

Page 84: ...ng 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 D707 and C710 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 ...

Page 85: ...nector disconnected The problem may 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 pat...

Page 86: ...cuit 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 R503 and peripheral circuits of system power module normal Replace the main P W B Is the system power module normal...

Page 87: ... 97 16 ...

Page 88: ...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 15 times blinking Yes No ...

Page 89: ... 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 ma...

Page 90: ...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 91: ...f 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 phase...

Page 92: ...atus Be sure to push the service switch 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 p...

Page 93: ... 103 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAD 50DH7A RAD 60DH7A RAD 70DH7A 3 12 2 1 5 6 4 6 5 7 8 9 10 11 11 18 17 16 13 20 19 9 ...

Page 94: ...08 1 BAND L 8 PMRAD 50DH7 009 1 BAND R 9 PMRAD 50DH7 010 1 DRAIN PUMP 10 PMRAD 50DH7 011 1 FILTER 11 PMRAD 50DH7 012 2 FILTER PLATE 12 PMRAD 50DH7 013 1 THERMISTOR SUPPORT 13 PMRAD 50DH7A R01 1 P W B MAIN 16 PMRAD 50DH7 014 1 ROOM THERMISTOR 17 PMRAD 50DH7 015 1 THERMISTOR 18 PMRAD 18NH7A R02 1 WIRE REMOTE CONTROL 19 PMRAS 70YHA 011 1 2P TERMINAL WITH FUSE 20 PMRAC 07CV1 R06 1 2P TERMINAL PART N0 ...

Page 95: ...08 1 BAND L 8 PMRAD 50DH7 009 1 BAND R 9 PMRAD 50DH7 010 1 DRAIN PUMP 10 PMRAD 50DH7 011 1 FILTER 11 PMRAD 50DH7 012 2 FILTER PLATE 12 PMRAD 50DH7 013 1 THERMISTOR SUPPORT 14 PMRAD 60DH7A R01 1 P W B MAIN 16 PMRAD 50DH7 014 1 ROOM THERMISTOR 17 PMRAD 50DH7 015 1 THERMISTOR 18 PMRAD 18NH7A R02 1 WIRE REMOTE CONTROL 19 PMRAS 70YHA 011 1 2P TERMINAL WITH FUSE 20 PMRAC 07CV1 R06 1 2P TERMINAL PART N0 ...

Page 96: ...08 1 BAND L 8 PMRAD 50DH7 009 1 BAND R 9 PMRAD 50DH7 010 1 DRAIN PUMP 10 PMRAD 50DH7 011 1 FILTER 11 PMRAD 50DH7 012 2 FILTER PLATE 12 PMRAD 50DH7 013 1 THERMISTOR SUPPORT 15 PMRAD 70DH7A R01 1 P W B MAIN 16 PMRAD 50DH7 014 1 ROOM THERMISTOR 17 PMRAD 50DH7 015 1 THERMISTOR 18 PMRAD 18NH7A R02 1 WIRE REMOTE CONTROL 19 PMRAS 70YHA 011 1 2P TERMINAL WITH FUSE 20 PMRAC 07CV1 R06 1 2P TERMINAL PART N0 ...

Page 97: ... 107 PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL RAC 50DH7 RAC 60DH7 RAC 70DH7 18 23 24 32 28 12 11 6 10 1 27 9 30 26 13 5 14 4 20 19 15 21 22 29 7 3 8 2 25 31 33 17 35 36 34 16 ...

Page 98: ...SYSTEM POWER MODULE 17 PMRAC 25NH4 S13 1 TERMINAL BOARD 4P 18 PMRAM 65QH4 S10 1 THERMISTOR OUTSIDE TEMPERATURE 19 PMRAC 70YHA 907 1 PROPELLER FAN 20 PMRAC 70YHA S12 1 SUPPORT FAN MOTOR 21 PMRAC 70YHA S04 1 FAN MOTOR 22 PMRAC 70YHA S01 1 CABINET 23 PMRAC 70YHA S06 1 NET 24 PMRAC 24CP5 905 1 TOP COVER 25 PMRAC 70YHA S09 1 SIDE PLATE R 26 PMRAC 70YHA 911 1 STRAINER COND 27 PMRAC 70YHA 910 1 STRAINER ...

Page 99: ...SYSTEM POWER MODULE 17 PMRAC 25NH4 S13 1 TERMINAL BOARD 4P 18 PMRAM 65QH4 S10 1 THERMISTOR OUTSIDE TEMPERATURE 19 PMRAC 70YHA 907 1 PROPELLER FAN 20 PMRAC 70YHA S12 1 SUPPORT FAN MOTOR 21 PMRAC 70YHA S04 1 FAN MOTOR 22 PMRAC 70YHA S01 1 CABINET 23 PMRAC 70YHA S06 1 NET 24 PMRAC 24CP5 905 1 TOP COVER 25 PMRAC 70YHA S09 1 SIDE PLATE R 26 PMRAC 70YHA 911 1 STRAINER COND 27 PMRAC 70YHA 910 1 STRAINER ...

Page 100: ...SYSTEM POWER MODULE 17 PMRAC 25NH4 S13 1 TERMINAL BOARD 4P 18 PMRAM 65QH4 S10 1 THERMISTOR OUTSIDE TEMPERATURE 19 PMRAC 70YHA 907 1 PROPELLER FAN 20 PMRAC 70YHA S12 1 SUPPORT FAN MOTOR 21 PMRAC 70YHA S04 1 FAN MOTOR 22 PMRAC 70YHA S01 1 CABINET 23 PMRAC 70YHA S06 1 NET 24 PMRAC 24CP5 905 1 TOP COVER 25 PMRAC 70YHA S09 1 SIDE PLATE R 26 PMRAC 70YHA 911 1 STRAINER COND 27 PMRAC 70YHA 910 1 STRAINER ...

Page 101: ...HITACHI PM NO 0411E Printed in Malaysia RAD 50DH7A RAC 50DH7 RAD 60DH7A RAC 60DH7 RAD 70DH7A RAC 70DH7 ...

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Hitachi RAC-50DH7, Service Manual

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