Hitachi RAC-50YH7 Service Manual Download Page 79

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TROUBLE SHOOTING

PRECAUTIONS FOR CHECKING

Power source

—

ACT

Module

—

Compressor motor

System power module 2

Indoor unit
electric parts

Control
P.W.B.

DC35V

(0V)

MAIN P.W.B.

Power module

1. Remember that the

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

2. Also note that it takes

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

DANGER

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

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

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

approx 260-360V

approx 155-170V

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

DANGER

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

DANGER!

Don’t install

the ground

line.

Oscilloscope

Outdoor unit P.W.B.

Summary of Contents for RAC-50YH7

Page 1: ... RAS 80YH5A CONTENTS SPECIFICATIONS 4 HOW TO USE 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM 30 MAIN PARTS COMPONENT 32 WIRING DIAGRAM 34 CIRCUIT DIAGRAM 35 PRINTED WIRING BOARD LOCATION DIAGRAM 41 BLOCK DIAGRAM 44 BASIC MODE 45 REFRIGERATING CYCLE DIAGRAM 59 DESCRIPTION OF MAIN CIRCUIT OPERATION 61 SERVICE CALL Q A 85 TROUBLE SHOOTING 88 PARTS LIST AND DIAGRAM 108 RAS 80YH5A RAC 80YH5 COOLING HEATING ...

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 Staple...

Page 5: ...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 6: ... TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL FUSE CAPACITY RAS 80YH5A 30 W NO NO NO NO NO 3 15A G4A NO YES NO NO 416NR NO YES IC YES RAC 80YH5 100 W NO NO JU1015D3 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 ADDITIONAL REFRIGERANT R410A AT 20g PER EVERY METER IF PIPE LENGTH MORE ...

Page 7: ...above 200 mm above 50mm above 100mm Be sure to completely seal any gap with putty The difference in height between the indoor and outdoor unit should be kept max 10m The connecting pipe no matter big or small should all be insulated with insulation pipe and then wrapped with vinyl tape The insulator will deteriorate if it is not wrapped with tape The connection of insulated drain hose Please use i...

Page 8: ...REMOTE CONTROLLER Send out operation signal to the indoor unit So as to operate the whole unit Refer page 12 AIR INLET BACK AND LEFT SIDE AIR OUTLET Blow out warm air Air cleansing filters are washable and can be use in 1 year time Type number for this air cleansing filter is SPX CFH12 Please use this number for ordering when you want to renew it Air cleansing filter should be cleaned every month ...

Page 9: ...eat exchanger of the outdoor unit for 5 10 minutes each time FILTER LAMP When the device is operated for a total of about 200 hours the FILTER lamp lights to indicate that it is time to clean the filter The lamp goes out when the AUTO SWING button is pressed while the device is on STANDBY MODE TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work Use non condu...

Page 10: ...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 Heating ...

Page 11: ...r 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 OPERATION Avoid an extended period of direct air flow for your health W A R N I N G Do not insert a finger a rod or other objects into the air outlet or inle...

Page 12: ...ter 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 equipments and etc the preset room temperature cannot be achieved This appliance is not intended ...

Page 13: ...lower the temperature setting Keep pressed and the value will change more quickly TIME button Use this button to set and check the time and date RESET buttons FUNCTION selector Use this button to select the operating mode Every time you press it the mode will change from AUTO to HEAT to DEHUMIDIFY to COOL and to FAN cyclically FAN SPEED selector This determines the fan speed Every time you press t...

Page 14: ...Timer mode is set As the settings are stored in memory in the remote controller you only have to press the START STOP button next time Press the FUNCTION selector so that the display indicates the AUTO mode of operation When AUTO has been selected the device will automatically determine the mode of operation HEAT COOL or DEHUMIDIFY depending on the current room temperature However the mode of oper...

Page 15: ...wer Set the desired room temperature with the TEMPERATURE buttons the display indicates the setting The temperature setting and the actual room temperature may vary somewhat depending on conditions Press the START STOP button Heating operation starts with a beep Press the button again to stop operation As the settings are stored in memory in the remote controller you only have to press the START S...

Page 16: ...top the indoor unit will stop emitting air as soon as the room temperature becomes lower than the setting temperature The preset room temperature may not be reached depending on the number of people present in the room or other room conditions 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 f...

Page 17: ...an 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 ...

Page 18: ...un at HI speed After room temperature reaches the preset temperature the cooling operation which changes the fan speed and room temperature to obtain optimum conditions for natural healthful cooling will be performed For the cooling operation FAN OPERATION You can use the device simply as an air circulator Use this function to dry the interior of the indoor unit at the end of summer Press the FUNC...

Page 19: ...ller toward the indoor unit and press the CANCEL button The RESERVED sign goes out with a beep and the TIMER lamp turns off on the indoor unit 1 Set the TIME 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...

Page 20: ...ntrol button The setting of turn off time is now complete Example The device will turn off at 11 00p m Example The device will turn on at 7 00 a m The setting of the turn on time is now complete 4Set the turn on time with the TIMER control button 5 Point the signal window of the remote controller toward the indoor unit and press the RESERVE button The ON mark starts lighting instead of flashing an...

Page 21: ...yed on the remote controller 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 s...

Page 22: ... 21 SHIFT VALUE ADJUSTMENT ...

Page 23: ...her 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 CIRCUIT BREAKER When you do not use the room air conditioner set the circuit breaker to OFF TEMPORARY SWITCH If the remote controller does not work due to battery failure press this switch to start and stop operation This temporary operation will be at the settin...

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

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

Page 26: ... filters push the front panel at three arrow portion as shown in figure and close it 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 filter as it may cause damage to the structure NOTE In case of removing the air cleansing filters please follow the above proc...

Page 27: ...lter and air cleansing filter using vacuum cleaner If there is too much dust air filter only rinse under running tap water and gently brush it with soft bristle brush Allow filters to dry in shade 3 Re insert the air cleansing 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 ...

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

Page 29: ...or unstable Is the plug of power line firmly plugged into the socket Please ensure no loose contact between them Cleaning and maintenance must be carried out only by qualified service personal Before cleaning stop operation and switch off the power supply CAUTION Confirm 3 MAINTENANCE AT BEGINNING OF LONG OFF PERIOD Air Blow Running the unit setting the operation mode to FAN and the fan speed to H...

Page 30: ... 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 contact your sales agent immediately if the air conditioner still fails to operate normally after the above inspections Inform your agent of the model of your unit production...

Page 31: ...e 1 6mm dia x 2 CD Line is used for the connection When piping is drawn horizontally exchange the drain hose for the drain cap Notes 1 Service space free space needed for servicing is 200mm on the right 100mm on the left and 50mm on top 2 The wide and narrow pipes must be thermally insulated Unit mm Wireless remote controller 147 56 17 5 About 380 Viewed from back bottom direction pipe lead out D ...

Page 32: ... 31 Note 1 200mm or more servicing space is required above the outdoor unit ...

Page 33: ...OL HEAT 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 100 322V 15V 0V 0 6 5V FG MODEL RAS 80YH5A POWER SOURCE DC 100 322V DC350V OUTPUT 30W 100W 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 34: ...tle coolant 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 2M 1 05 2M 1 268 U V W WHITE M M M YELLOW RED RAC 80YH5 JU1015D3 ...

Page 35: ... 34 INDOOR UNIT OUTDOOR UNIT A A A A WIRING DIAGRAM MODEL RAS 80YH5A RAC 80YH5 ...

Page 36: ... 35 CIRCUIT DIAGRAM Remote Control ...

Page 37: ... 37 CIRCUIT DIAGRAM MODEL RAS 80YH5A ...

Page 38: ... 39 CIRCUIT DIAGRAM MODEL RAC 80YH5 ...

Page 39: ... 41 PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAS 80YH5A MAIN P W B Marking on P W B COMPONENT SIDE SOLDERING SIDE RECEIVING P W B Marking on P W B ...

Page 40: ... 42 MODEL RAC 80YH5 MAIN P W B ...

Page 41: ... 43 MAIN P W B NF P W B CAPA P W B ...

Page 42: ...xchanger thermistor Room temperature thermistor Reset circuit Initial setting circuit Temporary switch Electric Expansion valve drive circuit Electric Expansion valve Outdoor microcomputer HIC AX 6V Trip signal synthesis circuit L N SPM2 Outdoor unit Terminal board Indoor microcomputer AX 7X30 DC35V Power circuit Noise filter Power circuit A B A B ...

Page 43: ...re 27 C 3 C cooling ii Room temperature 23 C 3 C heating iii Room temperature or room temperature 23 C dehumidifying 3 C is the shift value can be set by remote controller Judging operating mode change during operation continuous judgement a Condition for judgement any of followings The mode is reviewed at every internal time When auto operation is started again before 1 hour has elapsed since the...

Page 44: ...in 1 WSZMAX 4000 min 1 CMAX 5800 min 1 CSTD 5300 min 1 CJKMAX 4000 min 1 CBEMAX 4000 min 1 CSZMAX 3000 min 1 WMIN 1200 min 1 CMIN 1200 min 1 STARTMC 60 Seconds DWNRATEW 100 DWNRATEC 100 SHIFTW 0 C SHIFTC 1 00 C CLMXTP 30 00 C YNEOF 25 00 C TEION 2 00 C TEIOF 9 00 C SFTDSW 0 66 C DFTIM1 50 Minutes DFTIM2 50 Minutes KAFON 55 C KAFOF 44 C ...

Page 45: ...ration continues in fuzzy control 4 The compressor minimum ON time and OFF time is 3 minutes 5 During normal cooling mode CMAX will be maintained until 60 minutes when room temperature less than CLMXTP and no time constrain when room temperature is CLMXTP and above 6 If the fan speed set to Med mode by remote control maximum compressor rpm CJKMAX 7 If the fan speed set to Lo mode by remote control...

Page 46: ... 51 ...

Page 47: ...emote control the operation will be performed at any desired position of air deflector Dehumidifying Notes 1 If the room temperature is cooling preset temperature 1 33 C or less after 30 seconds from starting the operation the operation is done assuming as the preset temperature room temperature at the time 2 C 2 The indoor fan is operated in the Lo mode During thermo OFF indoor fan will be OFF fo...

Page 48: ...reheating defrosting including balance time after defrosting is finished or auto fresh defrosting 7 When heating mode start it will enter into hotkeep preheating if indoor heat exchanger temperature is lower than YNEOF 0 33 C and it will not enter if indoor heat exchanger temperature is equal or higher than YNEOF 0 33 C at the start of operation by using START STOP button 8 The limitation of compr...

Page 49: ... 57 ...

Page 50: ...N VALVE SERVICE VALVE SINGLE ENDED UNION 5 8 SINGLE ENDED UNION OUTDOOR UNIT COOLING DEHUMIDIFYING DEFROSTING 6 35 1 4 OUTDOOR UNIT HEATING SILENCER INDOOR UNIT SERVICE VALVE SUCTION TANK COMP REVERSING VALVE EXPENSION VALVE SERVICE VALVE SINGLE ENDED UNION 5 8 SINGLE ENDED UNION 6 35 1 4 SILENCER HEX THERMISTOR HEX THERMISTOR ...

Page 51: ...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 52: ...tential of Q201 s base rises and Q202 is turned ON Since Q202 s collector is set to LO at this time Q202 is turned OFF and the reset input of the micro computer is set to Lo The DC 5V line voltage has already become 5V at this time and the micro computer starts operation When the power is turned OFF the voltage of the DC 12V line decreases When it becomes about 7V ZD202 is turned OFF then Q201 is ...

Page 53: ...brates to output 4kHz sound 3 Initial setting IC301 The pre heating operation start value ratings of the compressor maximum rotation speed etc are preset in the micro computer 4 Receive circuit Infrared signals from the wireless remote controller are received by the light receiving unit and output after being amplified and shaped 8 7 IC401 E 2PROM 6 5 Micro computer AX 7X30 26 27 R404 R403 1 2 4 3...

Page 54: ...are output from pins of the micro computer Micro computer pins Step width Horizontal air deflectors 10ms 1 2 3 4 5 6 7 8 Horizontal air deflectors 15 16 17 18 Fig 5 2 Micro computer Output Signals As the micro computer s outputs change as shown in Fig 5 2 the core of the auto sweep motor is excited to turn the rotor Table 5 1 shows the rotation angle of horizontal air deflectors Rotation angle per...

Page 55: ...er temperature input R308 5 4 3 2 1 0 0 10 Fig 6 2 20 30 40 Voltage at V A 5 4 3 2 1 0 0 10 10 Fig 7 2 20 30 40 Voltage at V A 64 63 7 Heat exchanger temperature thermistor circuit The voltage at A depends on the room temperature as shown in Fig 6 2 The circuit detects the indoor heat exchanger temperature and controls the following 1 Low temperature defrosting during cooling and dehumidifying ope...

Page 56: ...SC 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 I O G 0V 20V 5V 5V 15V 0V VDC FM GND VCC VS FG JOINT CONNECTOR 1 3 4 5 6 340V R501 ZD201 ...

Page 57: ...faulty or defective connection Although the compressor continues to operate normally the power factor will decrease the operation current will increase and the overcurrent breaker of the household power board will probably activate Reference If diode stack 1 is faulty the compressor may stop due to lp anbormally low speed etc immediately after it starts or it may not operate at all because no DC v...

Page 58: ...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 59: ...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 60: ...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 61: ...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 62: ...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 63: ...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 64: ...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 65: ...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 66: ... 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 67: ...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 68: ...201 Fig 7 1 Peripheral circuit of microcomputer AX 6S 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 69: ...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 70: ...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 71: ...thermistor 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 80YHA and their roles and temperature measuring points are shown as Table 10 1 Fig 10 1 Temperature Detection Circuit ...

Page 72: ...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 73: ...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 74: ...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 75: ...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 76: ...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 77: ...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 78: ...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 79: ...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 80: ...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 81: ...e service switch for 1 sec Does the compressor operate After checking be sure to press the service switch to stop the operation Check the refrigerating cycle Check the outdoor electrical parts Check the indoor electrical parts Check to see whether the F cable is connected incorrectly or disconnected See Out door unit self diagnosis lamp lighting mode See Troubleshooting when the timer lamp blinks ...

Page 82: ...eading error When data read from IC401 or IC402 is incorrect 1 Reversing valve defective 2 Heat exchanger thermistor dis connected only in the heating mode Note The malfunction mode is entered the 3rd time this abnormal indication appears read every 3 minutes Electrical parts in the outdoor unit 1 Indoor interface circuit 2 Outdoor interface circuit Please check at the outdoor electrical led lamp ...

Page 83: ... 92 SELF DIAGNOSIS LIGHTING MODE DD0002204A ...

Page 84: ...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 85: ... 94 2 Outdoor unit does not operate but receives remote infrared signal ...

Page 86: ...T001 and interface relay 501 Disconnect joint connector at indoor fan motor and set to the fan mode again 4 Air deflector does not move others are normal 5 All systems stop from several seconds to several minutes after operation is started all indicators are also off ...

Page 87: ... 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 88: ... 97 CHECKING THE REMOTE CONTROLLER ...

Page 89: ...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 90: ...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 91: ...nnector 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 pa...

Page 92: ...rcuit 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 norma...

Page 93: ... 102 16 ...

Page 94: ...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 95: ...n the same condition as above The compressor is defective Replace it and seal refrigerant If the compressor checker for an inverter type air conditioner is available re check using it JUDGING BETWEEN GAS LEAKAGE AND COMPRESSOR DEFECTIVE Blinking off Time until the lamp lights Approx 10 seconds Approx 10 seconds Approx 10 seconds Within Approx 30 seconds Compressor Compressor Gas leakage Possible m...

Page 96: ...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 97: ...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 98: ...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 99: ... 108 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAS 80YH5A 1 9 4 5 8 2 3 12 11 10 7 28 6 29 20 16 19 13 15 18 22 14 26 17 33 ...

Page 100: ...2CHA3 R01 4 AUTO SWEEP MOTOR 12 PMRAS 72CHA3 R14 1 P W B LED 13 PMRAS 80YH5 003 1 FRONT COVER ASSY 14 PMRAS 80YH5 002 1 FRONT PANEL 15 PMRAS 10C7M 008 3 CAP 16 PMRAS 72CHA3 009 1 FILTER R 17 PMRAS 80YH5A R02 1 REMOTE CONTROL ASSY 18 PMRAS 10C3M 003 1 REMOTE CONTROL SUPPORT 19 PMRAS 72CHA3 008 1 FILTER L 20 PMRAS 72CHA3 022 1 THERMISTOR 22 PMRAS 80YH5A R01 1 P W B MAIN 26 PMRAS 72CHA3 R15 1 P W B R...

Page 101: ... 110 PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL RAC 80YH5 9 11 15 18 16 34 33 10 24 5 27 12 2 21 3 7 35 23 8 20 32 31 30 22 4 6 13 14 1 41 42 43 44 45 40 ...

Page 102: ...06 1 EXPANSION VALVE 18 PMRAC 80YHA 915 1 FAN MOTOR SUPPORT 20 PMRAC 80YHA 916 1 NET 21 PMRAC 81CHA3 904 1 GRILL 22 PMRAC 80YHA S14 1 OH TERMISTOR 23 PMRAC 30CVP1 911 1 PIPE COVER BACK 24 PMRAC 80YHA 904 1 FAN MOTOR 27 PMRAM 22NHZ4 S01 1 REVERSING VALVE 30 PMRAC 25NH4 S09 1 OVERHEAD THERMISTOR SUPPORT 31 PMRAC 25NH4 910 1 OVERLOAD RELAY COVER 32 KPNTI 001 3 PUSH NUT 33 PMRAC 70YHA 913 1 THERMISTOR...

Page 103: ...PM NO 0413E Printed in Malaysia RAS 80YH5A RAC 80YH5 ...

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Hitachi RAC-50YH7, Service Manual, Page: 79 / 103

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