Hitachi RAM-50CNHZ2 Service Manual Download Page 89

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LD301 blinks 8 times.

Acceleration error

LD301 blinks 7 times.

Thermistor abnormal.

Is system power module (SPM2)

normal?

Is drive circuit normal?

Is thermistor connected correctly?

Replace system power

module. (SPM2)

Replace defective parts.

Connect thermistor

Replace thermistor

Replace thermistor circuit

parts.

Looking at P

.B. diagram and

circuit diagram, perform continuity

check of pattern and lead wire.

Looking at P

.B. diagram and

circuit diagram, perform continuity

check of pattern and lead wire.

❈

Be careful not to forget to connect

it after servicing is completed.

Is continuity of thermistor normal?

Is thermistor circuit normal?

Summary of Contents for RAM-50CNHZ2

Page 1: ...N OUTDOOR 71 TROUBLE SHOOTING 95 PARTS LIST AND DIAGRAM 110 RAS 20CNHZ2 RAS 30CNHZ2 REFER TO THE FOUNDATION MANUAL INDOOR UNIT RAS 20CNHZ2 RAS 30CNHZ2 OUTDOOR UNIT RAM 50CNHZ2 DC INVERTER DUAL SYSTEM MULTI WALL TYPE SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ROOM AIR CONDITIONER INDOOR UNIT OUTDOOR UNIT MAY 2002 H A P M TYPE MODEL 1ø 220V 230V 50Hz POWER SOURCE TOTAL INPUT TOTA...

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

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

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

Page 5: ...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 the outside temperature is below...

Page 6: ...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 7: ...0 and with the air deflector facing down or moving automatically for a long period of time water will condense on the air 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 equi...

Page 8: ...MPUTER CIRCUIT FUSE MAIN SUPPLY FUSE FAN MOTOR POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL FUSE CAPACITY RAS 20CNHZ2 RAS 30CNHZ2 20 W NO NO NO NO NO NO NO NO NO NO YES NO NO NO NO YES IC YES SPECIFICATIONS 1350g UNIT PIPES MAX 35m REFRIGERANT CHARGING VOLUME Refrigerant 22 WITHOUT REFRIGERANT BECAUSE...

Page 9: ...RD REMOTE CONTROL SWITCH MAXIMUM LENGTH OF PIPING STANDARD RAS 20CNHZ2 1ø 220V 230V 50Hz 16 2 50 1 00 3 00 1000 300 1080 8 53 4 50 97 33 5 7m3 min RAS 30CNHZ2 3 20 1 00 3 30 8530 3412 10236 10919 3412 11260 1100 300 1160 9 93 5 00 96 35 8 5m3 min 2150 450 2200 8 57 9 40 99 50 5 40 1 00 5 60 18426 3412 19108 3 60 0 90 4 00 1470 120 1690 8 36 6 50 98 33 7 7m3 min 12284 3071 13649 4 50 0 90 4 60 1900...

Page 10: ...5m PIPING LENGTH L1 L2 Maximum 35m Maximum piping length for one indoor unit is 25m TWO UNITS 20m add 0g 25m add 25g 30m add 50g 35m add 75g Additional R 22 2 5 2 5 2 5 3 2 3 2 3 2 0g 0g Within 10 m Indoor unit 1 Indoor unit 2 Maximum 5 m Outdoor unit L2 L1 Indoor unit 1 Indoor unit 2 Outdoor unit ...

Page 11: ...t which was operated first or later and reset the type of operation then perform operation again One unit Heating Heating Heating Other unit Cooling Dehumidifying Circulating fan Adjusting the Number of Indoor Units The more the indoor units to be operated the lower the power of each unit Refer to the specification on installation manual Decrease the number of indoor units to be operated especiall...

Page 12: ...e 24 REMOTE CONTROLLER Send out operation signal to the indoor unit So as to operate the whole unit Refer page 14 AIR FILTER To prevent dust from coming into the indoor unit Refer page 31 INDOOR UNIT INDICATORS Light indicator showing the operating condition Refer page 13 FRONT PANEL AIR INLET HORIZONTAL DEFLECTOR VERTICAL DEFLECTOR AIR OUTLET Refer page 24 REMOTE CONTROLLER Send out operation sig...

Page 13: ...s done using the temporary switch after the power source is turned off and turn on again the operation is done in automatic mode 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 50 minutes when frost forms on the heat ex...

Page 14: ...n the following cases during heating 1 During preheating For about 2 3 minutes after starting up 2 During defrosting Defrosting will be performed about 50 minutes when frost forms on the heat exchanger of the outdoor unit for 5 10 minutes each time FILTER LAMP When the device is operated for a total of about 100 hours the FILTER lamp lights to indicate that it is time to clean the filter The lamp ...

Page 15: ...ange 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 16: ... 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 17: ... 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 18: ...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 19: ...ts 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 Th...

Page 20: ...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 21: ...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 22: ...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 23: ...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 24: ...nd the FAN SPEED will be set to LOW setting 30 minutes after the setting of the sleep timer Operation with the sleep timer The room temperature is kept at about 12 C minimum The room temperature is kept at about 25 28 C 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...

Page 25: ...n 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 may fall from it RESET Adjustment of the c...

Page 26: ...e old batteries 2 Install the new batteries The direction of the batteries should match the marks in the case 1 Do not use new and old batteries or different kinds of batteries together 2 Take out the batteries when you do not use the remote controller for 2 or 3 months CAUTION Push and pull to the direction of arrow ...

Page 27: ...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 28: ...cannot be achieved When the power is resumed after a power failure the indoor unit will still remain OFF To operate the unit please press the ON OFF button again When the indoor unit is not to be 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 m...

Page 29: ...lter RAS 20CNHZ2 Cleaning and maintenance must be carried out only by qualified service personal Before cleaning stop operation and switch off the power supply CAUTION CAUTION Do not bend the air cleansing and deodorizing filter as it may cause damage to the structure NOTE In case of removing the air cleansing and deodorizing filters please follow the above procedures The cooling capacity is sligh...

Page 30: ...ont panel at three arrow portion as shown in figure and close it Claws Front cover Front panel Air filter RAS 30CNHZ2 The cooling capacity is slightly weakened and the cooling speed becomes slower when the air cleaning and deodorizing filter is used So set the fan speed to HIGH when using it in this condition Air cleansing and deodorizing filters is washable and reusable up to 20 times by using va...

Page 31: ...e 3 Re insert the air cleansing and deodorizing filter to the filter frame Set the filter with FRONT mark facing front and slot them into the original state After attaching the filters push the front panel at three arrow portions as shown in figure and close it CAUTION Do not wash with hot water at more than 40 C The filter may shrink When washing it shake off moisture completely and dry it in the...

Page 32: ...there is too much dust rinse with clean water and gently brush it with soft bristle brush Allow filters to dry in shade 3 Re insert the air cleansing and deodorizing filter to the filter frame Set the filter with FRONT mark facing front and slot them into the original state After attaching the filters push the front panel at three arrow portions as shown in figure and close it CAUTION Do not wash ...

Page 33: ... 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 34: ...EGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS BY QUALIFIED SERVICE PERSONAL EVERY EITHER 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 Cleaning and maintenance must be carried out only by qualified service personal Before cleaning stop operatio...

Page 35: ...ng 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 on sticks to it So the air filter and the evaporator regularly must be cleaned to reduce the odor Please contac...

Page 36: ...10 60 5 7 798 P 265 44 45 5 5 60 60 47 47 174 450 174 87 58 58 25 43 94 5 MODEL RAS 30CNHZ2 Air suction grill Top air suction grill Mounting plate Wireless remote controller Front cover Viewed from back Pipe lead out Discharge grill Vertical air deflector Horizontal air deflector Hole on the wall for ø65 mm pipe Connecting cable Narrow pipe ø6 35 Wide pipe ø9 52 Drain cap connection part When pipi...

Page 37: ... 104 64 26 850 79 650 96 169 5 638 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 38: ...EAT ON 14 3 57 7 24 3 75 7 OFF 13 6 56 5 25 0 77 0 ON 22 3 72 1 32 3 90 1 OFF 21 6 70 9 33 0 91 4 ON 30 3 86 5 40 3 104 5 OFF 29 6 85 3 41 0 105 8 M RED YEL BLU 5V 0 35V MODEL RAS 20CNHZ2 RAS 30CNHZ2 RAM 50CNHZ2 POWER SOURCE DC 5V DC 0 35V DC360V OUTPUT 20W 40W Control circuit built in BLU BLUE YEL YELLOW BRN BROWN WHT WHITE GRY GRAY ORN ORANGE GRN GREEN RED RED BLK BLACK PNK PINK VIO VIOLET RED 3...

Page 39: ...ide the compressor If the color has been changed conspicuously replace the compressor MODEL RAM 50CNHZ2 COMPRESSOR MODEL GW20DN8A PHASE SINGLE RATED VOLTAGE AC 220 230 V RATED FREQUENCY 50 60 Hz POWER SOURCE FOR COMPRESSOR Vcc max 360V POLE NUMBER 4 COMPRESSOR MOTOR Compressor Motor Specifications CONNECTION 20 C 68 F 75 C 167 F RESISTANCE VALUE 2M 1 05 2M 1 28 U V W WHITE YELLOW RED WHITE RED YEL...

Page 40: ...From Outdoor Terminal Board Green Yellow Red Brown Room Temperature Gray Gray Wireless Remote MAIN P W B C D CN1 CN2 CN4 CN10 Indoor Fan Motor Auto Sweep Motor Heat Exchanger Black Black TEST CN6 CN7 HA MODEL NAME X RAS 20CNHZ2 7 RAS 30CNHZ2 6 Thermistor Thermistor Unit P w b Control M2 M1 C1C2 X Lines 3 1 3 2 1 2 4 ...

Page 41: ... 40 WIRING DIAGRAM MODEL RAM 50CNHZ2 OUTDOOR UNIT ...

Page 42: ...G3 SEG2 SEG1 SEG0 SEG43 SEG42 SEG41 SEG40 P40 P41 P42 P43 P00 P01 P02 P03 P10 P11 P12 P13 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 BEEP P20 P30 P31 NCVL C1 VL C2 VL C3 XC IN XC OUT VDD X OUT X IN RESET CARR P23 P22 P21 VSS IC 1 M3455OM6A 504FP LCD 1 C8 50v 1u K 1 D3 RB425D 1 2 K2K3 K4 K5 P10 P11 P12 K6 K7 K8 K8 K10 K11K12 K18 K17 K15 K16 K13 K14 D0 D1 D2 D3 R1 100k SW1 R2 P 100k R3 100k R4 100k R5 Q1 2SC3443...

Page 43: ...1 LIGHT RECEIVING UNIT LD702 TIMER LD703 OPERATION R710 R709 ZD701 3 2 1 IR701 NOTES 1 TYPE F FILM C CERAMIC D ELECTROLYTIC 2 FORM H HAND INSERT C SMT R RADIAL A AXIAL R105 R106 R107 R108 R109 1 5 1 5 1 5 1 5 1 5 5 5 5 5 5 1 4W 1 4W 1 4W 1 4W 1 4W C C C C C R506 R507 R508 R509 R510 R511 R512 R513 R514 R515 R516 R517 R518 R519 R520 R604 R605 1K 10K 5 5 1 16W 1 16W C C R804 R805 R806 R807 120K 120K ...

Page 44: ...C C ZD102 PTZ20A C POWER SUPPLY RESET IF CIRCUIT AUTOSWEEPMOTOR3 AUTO SWEEP MOTOR 2 AUTO SWEEP MOTOR 1 INDICATINGP C B H BOARD LIGHT RECEIVING UNIT LD702 TIMER LD703 OPERATION NOTES 1 TYPE F FILM C CERAMIC D ELECTROLYTIC 2 FORM H HAND INSERT C SMT R RADIAL A AXIAL R105 R106 R107 R108 R109 1 5 1 5 1 5 1 5 1 5 5 5 5 5 5 1 4W 1 4W 1 4W 1 4W 1 4W C C C C C R506 R507 R508 R509 R510 R511 R512 R513 R514 ...

Page 45: ... 5 1 4 5 2 7K 1 4 A R724 5 3 3K 1 4 A R726 R730 33 A R723 5 1 6 5 3g 1 4 C R802 3g C R801 5 1 4 5 3g 1 4 C R811 3K C R803 5 1 16 5 3K 1 16 C R813 3g C R812 5 1 4 5 10K 1 6 A R831 5 620 1 6 A R833 7 5K A R832 5 1 2 A R717 1 4 A R725 1 4 2125 1 2K 5 1K 1 16 1 16 1 16 10K C R290 5 1K C R289 1 C R288 2K C R287 5 C R286 1 16 1 16 1608 1608 1608 1608 1608 1 16 4 7K C R291 5 1608 R285 1 16 1 6K C R293 5 ...

Page 46: ...or drive circuit Indoor Outdoor interface circuit Terminal Board Temporary switch Auto Restart Reset circuit Initial setting circuit Heat exchanger temperature thermistor Indicating lamp Auto sweep motor for Air deflector Buzzer circuit Operation Timer Indoor micro computer AX 7M12 LCD wireless Room temperature thermistor Wireless receive circuit M FM Indoor Outdoor interface circuit 2 Power circu...

Page 47: ... 51 BASIC MODE MODEL RAM 50CNHZ2 ...

Page 48: ... minutes after the sleep key is set the sleep shift of temperature starts and upper shift is made at least 6 times If 25 C is not reached after 6 shifts shifts repeat unit 25 C is reached 3 The sleep shift upper value of set temperature is 28 C 4 After 6 hours a shift down to the initial set temperature is made at a rate of 0 33 C 5 min 5 If the operation mode is changed during sleep operation the...

Page 49: ... 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 thermostat 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 opera...

Page 50: ... 57 ...

Page 51: ... 59 ...

Page 52: ...ed to initial condition ASTUS 0 Released by condition 1or 2during reversing cycle period Shifted to balancing period 3 Outputs during defrost Indoor defrost request Transmitted to all units being operated in heating mode Compresor Balancing period for TDF414 seconds Starting of reversing cycle period by SDRCT2 min 1 for TSKTM2 seconds Accelerating by DFCTEP min 1 TDFSPT seconds in remaining revers...

Page 53: ... DFPSMX DFPSMX DFCTPS Defrosting request 30sec Defrosting request Time chart when executing defrost both unit 1 and unit 2 operated Defrosting signal Unit 1 Unit 2 Unit 1 Unit 2 Unit 2 Unit 2 Unit 1 Unit 1 Turns on for cooling Cooling output Heating output Outdoor fan Compressor rotation speed 480 480 0 0 Electric expansion valve Reversing valve Request Compressor Operation Defrosting inhibit peri...

Page 54: ...ing auto fresh Indoor unit defrost request Transmitted only to unit to which auto fresh is applied 9indoor unit stopped last Compressor Accelerated by DFSTEP rpm TDFSPT seconds and reaches defrost MAX speed DEFMAX Electric expansion valve Unit auto fresh not applied FULL CLOSE when balancing for 30 seconds has elapsed at start of defrost Unit auto fresh applied Synchronized with step up of rotatio...

Page 55: ... is fixed in 3900min 1 during forced cooling compressor fixed speed control at start is not performed The following shows the operation state of forced cooling Power Power In rush Prevention Approx 100ms 31 25PPS Hold 500ms Hold 500ms Initialization finished TSKTM1 3900rpm Balancing period 3min 15sec sub 80sec 100ms Service switch Heating output Cooling output Outdoor fan Turns on for Heating Oper...

Page 56: ...g COMPRESSOR SUCTION TANK Indoor unit 12 7 12 7 Service valve 12 7 12 7 Adapter IN CASE CONNECTING TO INDOOR RAS 30CNHZ2 1 Fix the Adapter to Service valve 9 52 as show below 2 Connect the connecting pipe to the Adapter 12 7 12 7 9 52 9 52 9 52 9 52 6 35 6 35 6 35 6 35 6 35 6 35 6 35 6 35 6 35 6 35 6 35 12 7 AIR FLOW Reversing valve Service valve 3 8 Silencer Silencer Strainer Strainer Air Flow Ai...

Page 57: ...is time Q202 turns on and the reset input of the micro computer goes Hi The 5V DC line has already been 5V at this time and the micro computer starts operation When power is OFF the voltage on the 35V DC line drops and when it is approx 27V ZD201 turns off Q201 and Q202 turn off and the reset input of the micro computer goes Lo to reset it DESCRIPTION OF MAIN CIRCUIT OPERATION INDOOR MODEL RAS 20C...

Page 58: ...01 LIGHT RECEIVING UNIT Wireless input Micro computer AX 7M12 When the buzzer sounds an approx 3 9kHz square signal is output from buzzer output pin U 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 dia...

Page 59: ...ig 4 2 are output 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 42 41 40 39 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 Rotatio...

Page 60: ...emperature input R308 A 5 4 3 2 1 0 0 10 10 Heat exchanger temperature ßC Fig 6 2 20 30 40 Voltage at V A 1 64 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 ...

Page 61: ...UTO RESTART AUTO RESTART NORMAL MODEL RAS 30CNHZ2 Micro Computer AX 7M12 Micro Computer AX 7M12 C605 C601 0V R611 R609 SW1 HA INPUT Micro Computer AX 7M12 36 5V R602 R601 SW2 0V X1 34 L501 5V 5V L501 34 X1 SW701 R704 R706 7 Auto Restart Temporary Switch Auto Restart Switch Temporary Switch ...

Page 62: ...ut voltage is divided by R919 and R920 and is input to divided voltage output pin the micro computer controls the fan PWM output so the output voltage is set to the specified value The chopper frequency of the fan PWM output is 15 7kHz In the Fan current detection circuit 35V line current is detected by R105 R109 and input to abnormal fan current sensor pin L Microcomputer detects overcurrent comp...

Page 63: ...it may stop due to abnormally low speed active error etc The compressor may continue to operate normally but the power factor will decrease the operation current will increase and the overcurrent breaker of the household power board will probably activate In case of active module faulty or defective contact Although the compressor continues to operate normally the power factor will decrease the op...

Page 64: ...ed 4 Smoothing capacitor C020 C021 This smoothes averages the voltage rectified by the diode stacks A DC voltage is generated in the same way as in Fig 1 3 Voltage between 丣 side of C020 and 両 side of C021 is about 330V Vd DC Voltage Fig 1 2 Fig 1 3 C501 L a b a b OV OV N C502 C503 Vd DC Voltage Approx 330 or 360V during operation GRN3 GRN1 Reactor SPM2 Smoothing capacitor C501 C502 C503 Power P W...

Page 65: ...al while it is outputting a request signal The receiving circuit in the indoor unit consists of a comparator and transistor The interface signal from the outdoor unit on the DC 35V line is supplied to C821 where DC components are eliminated and is then shaped by the comparator The shaped signal is detected by diode amplified by amp and supplied to receiving k input of the indoor microcomputer Fig ...

Page 66: ...om indoor micro computer to outdoor microcomputer Communications from outdoor micro computer to indoor microcomputer Fig 2 1 Indoor outdoor interface Circuit MAIN P W B MAIN P W B POWER P W B INDOOR P W B OUTDOOR P W B IF RECEIVE SD1 IF TRANSMIT SD0 MICRO COMPUTER AX 7M12 IF CLOCK IF RECEIVE SDI1 IF TRANSMIT SD01 MICRO COMPUTER AX 6M00 ...

Page 67: ...7 5ms Transmit receive switching time 33ms 1 frame 0V 5V 0V 5V 0V 5V 0V 35V Base of outdoor P W B Q801 Q802 Outdoor micro computer pin 71 69 Indoor micro computer pin 35V DC line 48 49 Pin 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 68: ...he 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 R24 ACT MODULE 0 35 m H Power relay Coil R002 R003 Inrush current protection relay C006 R004 Noise filter coil L N Terminal board FUSE 25A INVERTER Fig 3 1 System power module circuit U is ON V is ON ...

Page 69: ...oportional to duty ratio ON time ON time OFF time of this chopper signal Time T in Fig 3 2 shows the switching period and relation with rotation speed N of the compressor is shown by formula below Fig 3 2 Switching order of power module N 60 2 X 1 T Fig 3 3 shows voltage 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 ...

Page 70: ...control P W B may indicate as shown below From results 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 ON V is ON Self diagnosis Self diagnosis lamp and mode lp peak current cut LD301 Abnormal low speed rotation LD301 Swi...

Page 71: ... microcomputer peripheral circuits and system power module drive and as well as DC35V are produced by switching power circuit Switching power circuit performs voltage conversion effectively by switching transistor IC1 to convert DC330V voltage to high frequency of about 20kHz to 200kHz Transistor IC1 operates as follows 1 Shifting from OFF to ON DC about 330V is applied from smoothing capacitors C...

Page 72: ...when both the indoor and outdoor units stop This reduces power loss in standby status Reference If the power circuit for P W B seems to be faulty 1 Make sure that 5V 12V 15V 17V and 5V on the control P W B power voltage are the specified values 2 When only the 5V output is low REG 1 regulator faulty 5V 0V shorted output is too high or REG 1 is abnormal 3 When 12V and 5V are abnormal The following ...

Page 73: ...low when measured by tester When collector voltage of Q831 is measured 3 1 24 0V Fig 5 1 D831 CN2 Q831 DC voltmeter or tester Reversing valve R832 R833 IC8 Micro Computer PQ831 12V 35V R831 V Operation condition Collector voltage of Q831 Cooling Heating Dehumidifying General operation of Cooling In normal heating operation MAX rotation speed instructed by indoor microcomputer after defrost is comp...

Page 74: ...ge divided by R501 R502 and R608 and inputs this to microcomputer as position detection signals for points C D and E Microcomputer switches inverter using optimum timing based on position detection signals in order to control the rotation of the brushless motor Microcomputer of outdoor unit 18 59 C 1 2 13 14 12 8 9 10 11 4 5 6 7 3 D B A E 19 20 C605 C606 OV OV 5V 12V OV OV OV OV C607 IC3 R601 R253...

Page 75: ...computer This circuit detects DC current flowing to power module and produces signal to notify microcomputer of overload status This circuit voltage amplifies DC cuccrent level detected by detection resistor and sends it to microcomputer In addition setting of internal external overload judgment is performed This circuit produces reset voltage 48 9 61 8 5 7 6 4 60 Is D104 R110 R278 R222 D205 R221 ...

Page 76: ...tive Terminal DC current 0V R24 R41 0V R43 0V OC R42 SPM HIC Control P W B IC1 CN14 IP cutter Outdoor microcomputer F C43 9 9 8 20 9 2 9 B Ip cut circuit detects instantaneous surge current and stops inverter to protect components such as SPM As shown in diagram when current exceeding 24A flows voltage at point A detected by detection resistor is input to pin 9 of INV HIC and voltage divided by R4...

Page 77: ... amplifier circuit Internal judgement DC voltage Judgement value according to the rotation speed internal judgement value OVL judgment to external set value A D converter E2PROM built in A D converter OVL judgment according to rotation speed Data selection according to rotation speed DC voltage OVL start current data Rotation speed data Motor control process AX 6M00 microcomputer Detection resisto...

Page 78: ...d sends this to microcomputer Microcomputer A D converts it and then compares with internal data to judge over load control During overload control Voltage generated from DC current flowing to detection resistor is balanced by resisitor R245 and C220 then input to pin 5 of IC4 IC4 composes non inverting amplifies combined with peripheral components As shown in Fig 8 5 a value varying according to ...

Page 79: ... change in power voltage The control system deals with change in voltage as shown below 1 As shown in Fig 8 6 U and V transistors on power module are turned on to apply current to winding of motor 2 As shown in Fig 8 7 ON time of W transistor changes according to DC voltage level so that starting current is about 10A Fig 8 5 DC current 0 0 Rotation speed Amplification rate low DC voltage low DC cu...

Page 80: ... 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 However Q208 is left ON since reset voltage is fed back by R294 until 12V line drops to about 7 6V This prevents chattering of reset voltage due to voltage chnge in 12V line Micro computer AX 6M...

Page 81: ... SDO pin of interface pin and X of microcomputer Outdoor temperature is always read in voltage at pin v of microcomputer by outdoor temperature thermistor and then transferred to indoor unit side According to this value compressor rotation speed control and operation selection outdoor fan ON OFF etc in dehumidifying mode are performed Represented values of the relationship between outdoor temperat...

Page 82: ...chopper signal is output from microcomputer for each phase The signal output from microcomputer is input to IC inverted due to active LO and 0 to 15V chopper signal is obtained This signal is then applied to transistor gate of each phase to drive AX 6M00 MICRO COMPUTER A B B B COMPRESSOR MOTOR IP CUTTER Id CONTROL CIRCUIT GRY PWB MAIN Fig 11 1 ...

Page 83: ... 91 120 U U V W W V U U U V V V W W 120 120 120 120 V V W W W U U V Drive signal at point Drive signal at point B 5V 0V 15V 0V A Fig 11 2 ...

Page 84: ...expansion valve or microcomputer is defective Fig 12 2 shows logic waveform when expansion valve is operating 2 8 1 9 16 1 2 3 4 5 6 3 39 15 14 40 7 6 41 10 11 42 4 5 12 13 Microcomputer Valve Valve Valve Valve B A B A IC6 7 5V R208 12V 12V C225 R209 O CN15 16 Electric expansion valve 1 V Fig 12 1 Pin Lear phase No wire 4 4 5 6 7 8 3 3 2 2 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 1 1 White Yellow Orange Bl...

Page 85: ...l signal will convert to Vsp voltage by smoothing circuit Q101 RC filter Fan motor will start to rotate when Vsp was proceeding over than 1 7V and generate FG pulse by rotation speed FG pulse will feed back to Outdoor Microprocessor through PQ102 PQ102 is the isolator between Microprocessor circuit and DC Fan Motor circuit which has to match the Fan Motor revolution with instructed revolution Such...

Page 86: ...turb the Fan rotation by inserting materials into propeller fan or ice has growing inside of outdoor unit by snowing Fan lock detecting system may be actidiated by strong wind ex 17m sec or above against the Fan rotation In this case unit will be restart again after a while Fan lock detecting system may be actidiated even though the DC Fan Motor is rotating correctly the possible casue is due to M...

Page 87: ...perate outdoor unit independently How is self diagnosis lamp LD301 lighting If fuse is blown other parts may be affected Take care Mainly varistor 2 diode stack smoothing capacitor and system power module Is switching power circuit OK Is 3A fuse normal Refer to lighting mode of self diagnosis lamps Replace defective components Check to see whether the connected cord D cable correctly If reversed c...

Page 88: ...l terminals of interface relay Is voltage 10V or more being generated between contact terminals of interface relay Check interface curcuit Yes Yes No No No Yes D707 and C710 could be defective There may be defective parts between 12V output of switching power supply on control P W B and interface relay Also be care of solder touch etc Repalce interface relay Yes No Which is broken C D Indoor 1 Or ...

Page 89: ...ule SPM2 Replace defective parts Connect thermistor Replace thermistor Replace thermistor circuit parts Looking at P W B diagram and circuit diagram perform continuity check of pattern and lead wire Looking at P W B diagram and circuit diagram perform continuity check of pattern and lead wire No No Yes Be careful not to forget to connect it after servicing is completed Is continuity of thermistor ...

Page 90: ...rmistor circuit normal Is system power module SPM2 normal Replace main P W B Is system power module normal SPM2 Replace thermistor circuit parts Replace system power module SPM2 Replace system power module SPM2 No No No Looking at P W B diagram and circuit diagram perform continuity check of pattern and lead wire Yes Yes No No No Yes Yes Yes Is drive circuit normal Replace defective parts ...

Page 91: ...n so this is not abnormal Is system power module normal SPM2 Is drive circuit normal Yes No No No Replace system power module SPM2 Replace defective parts Replace defective parts Try operation again Is operation normal Perform final check of operation No Yes Is reset circuit normal Check again to see that all connectors are connected securely ...

Page 92: ...lamp lighting Where OVL lamp lights this indicates over load and is not abnormal Yes Check cords connected to system power module again If any cord is disconnected connect correctly Check diode stack If phenomenon persists replace system power module Over voltage error blinks 15 times System power module SPM2 is abnormal No ...

Page 93: ...t 10 cm long with alligator clip or IC clip 1 Connect pipe to high pressure and low pressure side service valves Connect large diameter and small diameter side service values of outdoor unit using universal union and copper pipe as shown on the right Note 1 When checking is performed using service switch of outdoor unit if both indoor units are not connected to interface signal DC35V C D terminals...

Page 94: ...round level 2 Also note that it takes about 10 minutes until the voltage fall after the power switch is turned off DANGER Across a b 0V line Across a ground Across b 0V line ground approx 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 ...

Page 95: ...rformed to prevent secondary trouble disconnect red gray wire connected to system power module SPM2 from diode stack Also be sure to perform discharging of smoothing capacitor DISCHARGE PROCEDURE AND HOW TO CUT OFF POWER TO POWER CIRCUIT WARNING As shown left apply soldering iron to metal parts receptacles in sleeve corresponding to P1 and N1 terminals of system power module SPM2 RAM 50CNHZ2 GRN3 ...

Page 96: ...efective parts Around outdoor interface transmitting circuit Check indoor interface transmitting circuit Check electrical parts of outdoor unit and repair defective parts Around outdoor interface transmitting circuit Check room temperature thermistor If defective replace it Normal values 10 C approx 20kΩ 25 C approx 10kΩ 30 C approx 8kΩ Check heat exchanger thermistor If defective replace it Norma...

Page 97: ...SIS LAMP GRN3 GRN1 Reactor SPM2 Smoothing capacitor C501 C502 C503 Power P W B Terminal Board 2p Diode Stack D25 VB60 Switching Power P W B For Indoor P W B Service switch Control P W B RAM 50CNHZ2 1 Location of self diagnosis lamp ...

Page 98: ...OWER VOLTAGE CONNECTION OF REACTOR FAN MOTOR FAN MOTOR CIRCUIT CABLE IS WRONG CONNECTED CABLE IS OPEN INTERFACE CIRCUIT BETWEEN INDOOR UNIT AND OUTDOOR UNIT COMMUNICATIONS BETWEEN INDOOR UNIT AND OUTDOOR UNIT ARE INTERRUPTED OVERVOLTAGE IS DETECTED BY SYSTEM POWER MODULE MICROCOMPUTER CANNOT READ THE DATA IN EEPROM OUTDOOR FAN RPM IS NOT ROTATE AS INTENDED RPM POWER VOLTAGE IS ABNORMALLY LOW THERM...

Page 99: ...ector Emitter PGU PGV PGW NGU NGV NGW U V W P1 P2 U N1 L2L1 Element circuit Circuit diagram of the module Terminal symbol of system module See next page for values measured by tester Do not disassemble the system power module when troubleshooting is performed ...

Page 100: ...er since built in battery is set in reverse direction and terminals are reversed CAUTION 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 Fig 2 it is normal Furthermore compare how indicator swings at U V and W phases If indicator ...

Page 101: ...is 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 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 le...

Page 102: ... 110 PARTS LIST AND DIAGRAM MODEL RAS 20CNHZ2 11 2 18 8 20 12 63 1 4 60 3 7 14 15 6 5 16 13 88 61 17 9 62 10 ...

Page 103: ...PMRAS 07C1 013 1 DRAIN HOSE 11 PMRAS 20CNHZ2 003 1 FRONT COVER ASS Y 12 PMRAS 25CNH2 012 1 MOUNTING PLATE 13 PMRAS 40CNH2 021 1 REMOTE CONTROL 14 PMRAS 25CNH2 014 3 EVAPORATOR 15 PMRAS 10C6M 006 3 UNION 2 16 PMRAS 09CHA1R 005 1 UNION 3 17 PMRAS 10C6M 001 1 STEP MOTOR 60 PMRAS 10C3M 003 1 REMOTE CONTROL HOLDER 61 PMRAS 25CNH2 018 1 FILTER 62 PMRAS 25CNH2 019 2 CAP 63 PMRAS 25CNH2 020 1 PIPE SUPPORT...

Page 104: ... 112 MODEL RAS 30CNHZ2 8 12 23 1 3 5 60 14 4 7 6 13 61 61 11 62 35 12 10 9 17 2 63 18 19 15 16 ...

Page 105: ...RAS 30CNHZ2 004 1 FRONT COVER ASS Y 12 PMRAS 05C 009 1 MOUNTING PLATE 13 PMRAS 40CNH2 021 1 REMOTE CONTROL 14 PMRAS 30CNHZ2 005 1 EVAPORATOR 15 PMRAS 13C6K 003 1 UNION 2 16 PMRAS 5142C 006 1 UNION 4 17 PMRAS 05C 041 1 STEP MOTOR 18 PMRAS 07C1 006 1 TERMINAL 2P 19 PMRAS 30CNHZ2 001 1 PWB MAIN 23 PMRAS 32CNH2 009 1 INDICATION BOARD 35 PMRAS 25CNH2 024 1 THERMISTOR 60 PMRAS 10C3M 003 1 REMOTE CONTROL...

Page 106: ... 114 9 33 4 32 14 3 1 27 24 35 26 13 7 5 22 19 30 29 23 21 20 16 36 28 31 34 37 11 12 10 15 6 2 8 9 38 40 41 18 17 MODEL RAM 50CNHZ2 ...

Page 107: ...CNH2 906 1 FUSE 2A 20 PMRAC 40CNH2 901 1 SYSTEM POWER MODULE 21 PMRAC 40CNH2 902 1 DIODE STACK D25VB60 22 PMRAS 07C1 006 2 TERMINAL BOARD 2P 23 PMRAC 40CNH2 916 1 THERMISTOR OUTSIDE TEMPERATURE 24 PMRAC 40CNH2 917 1 PROPELLER FAN 26 PMRAC 40CNH2 918 1 SUPPORT FAN MOTOR 27 PMRAM 50CNHZ2 912 1 FAN MOTOR 40W 28 PMRAC 40CNH2 904 1 CABINET 29 PMRAC 40CNH2 921 1 NET 30 PMRAC 40CNH2 922 1 TOP COVER 31 PM...

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Summary of Contents for RAM-50CNHZ2

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Hitachi RAM-50CNHZ2, Service Manual, Page: 89 / 107

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