Hitachi RAS-S24H2A Service Manual
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Hitachi RAS-S24H2A Service Manual

Hitachi RAS-S24H2A Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
RAS-S24H2A
SPECIFICATIONS
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
COOLING
CAPACITY
TOTAL INPUT
TOTAL AMPERES
HEATING
CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
APRIL 2008
RAC-S24H2
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)
INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
RAS-S24H2A/RAC-S24H2
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 5
HOW TO USE ------------------------------------------------------------------------ 7
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 29
MAIN PARTS COMPONENT --------------------------------------------------- 31
WIRING DIAGRAM ---------------------------------------------------------------- 33
CIRCUIT DIAGRAM --------------------------------------------------------------- 34
PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 37
BLOCK DIAGRAM ----------------------------------------------------------------- 38
BASIC MODE ----------------------------------------------------------------------- 39
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 46
AUTO SWING FUNCTION ------------------------------------------------------ 47
DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 48
TROUBLE SHOOTING ----------------------------------------------------------- 82
PARTS LIST AND DIAGRAM ------------------------------------------------- 102
DC INVERTER (WALL TYPE)
INDOOR UNIT
RAS-S24H2A
1 PHASE, 50 Hz, 220 - 240V
2,300 (155 - 2500)
10.60 - 9.70
6.05 (0.90 - 6.50)
20,660
2,400 (115 - 2700)
11.0 - 10.10
7.05 (0.90 - 9.00)
24,060
1,030
295
191
11
SM0419
CONTENTS
OUTDOOR UNIT
RAC-S24H2
850
650
298
45
After installation

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  • Page 1: Table Of Contents

    SM0419 RAS-S24H2A/RAC-S24H2 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ------------------------------------------------------------------- 5 HOW TO USE ------------------------------------------------------------------------ 7 CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 29 MAIN PARTS COMPONENT --------------------------------------------------- 31 WIRING DIAGRAM ---------------------------------------------------------------- 33 CIRCUIT DIAGRAM --------------------------------------------------------------- 34...
  • Page 2 SAFETY DURING REPAIR WORK 1. In order to disassemble and repair the unit in question, be sure to disconnect the power cord plug from the power outlet before starting the work. 2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and the replacement must be effected in correct manner according to the instructions in the Service Manual of the unit.
  • Page 3 WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS 1. Scope The standards provide for items to be generally observed in carrying and handling semiconductors in relative manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal goods such as rejected goods being returned).
  • Page 4 (6) Use a three wire type soldering iron including a grounding wire. Metal plate (of aluminium, stainless steel, etc.) Working table Resistor of 1 M (1/2W) Staple Earth wire Bare copper wire (for body earth) Fig. 3. Grounding of the working table Soldering iron Grounding wire...
  • Page 5 CAUTION In quiet or stopping operation, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally, but this noise is not abnormal for the operation. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 6: Specifications

    SPECIFICATIONS RAS-S24H2A RAC-S24H2 MODEL 40 W PWM DC35V FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR – JU1013D5 COMPRESSOR COMPRESSOR MOTOR CAPACITOR YES (INTERNAL) OVERLOAD PROTECTOR OVERHEAT PROTECTOR 3.0A FUSE (for MICROPROCESSOR) POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH...
  • Page 7 Figure showing the installation of Indoor and Outdoor unit CAUTION In case the pipe length is more than 20m, add refrigerant R410A at 5 gram per every meter exceeds. However, pipe length shall not exceed 30m. Be sure to above 50mm completely seal any gap above 100mm...

  • Page 8: How To Use

    Condensed water drain to outside. CONNECTING CORD AND INSULATION PIPE FOR PIPING AIR INLET (BACK AND LEFT SIDE) AIR OUTLET Blow out warm air. MODEL NAME AND DIMENSIONS DEPTH (mm) MODEL WIDTH (mm) HEIGHT (mm) RAS-S24H2A 1030 RAC-S24H2 – 7 –...
  • Page 9 TIMER LAMP This lamp lights when the timer is working. OPERATION LAMP This lamp lights during operation. The OPERATION LAMP flashes in the following cases HITACHI during heating. (1) During preheating For about 2–3 minutes after starting up. (2) During defrosting...
  • Page 10 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 Minimum Maximum Minimum Maximum...
  • Page 11 SAFETY PRECAUTION ● Please read the “Safety Precaution” carefully before operating the unit to ensure correct usage of the unit. ● Pay special attention to signs of “ Warning” and “ Caution”. The “Warning” section contains matters which, if not observed strictly, may cause death or serious injury. The “Caution” section contains matters which may result in serious consequences if not observed properly.
  • Page 12 PRECAUTIONS DURING OPERATION The product shall be operated under the manufacturer specification and ● not for any other intended use. ● Do not attempt to operate the unit with wet hands, this could cause fatal accident. ● When operating the unit with burning equipments, regularly ventilate the room to avoid oxygen insufficiency.
  • Page 13 NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT REMOTE CONTROLLER ● This controls the operation of the indoor unit. The range of control is about 7 meters. If indoor lighting is controlled electronically, the range of control may be shorter. This unit can be fixed on a wall using the fixture provided. Before fixing it, make sure the indoor unit can be controlled from the remote controller.
  • Page 14 VARIOUS FUNCTIONS ■ Auto Restart Control ● If there is a power failure, operation will be automatically restarted when the power is resumed with previous operation mode and airflow direction. (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.
  • Page 15 HEATING OPERATION ● Use the device for heating when the outdoor temperature is under 21°C. When it is too warm (over 21°C), the heating function may not work in order to protect the device. ● In order to keep reliability of the device, please use this device above -15°C of the outdoor temperature. Press the FUNCTION selector so that the display indicates (HEAT).
  • Page 16 DEHUMIDIFYING OPERATION Use the device for dehumidifying when the room temperature is over 16°C. When it is under 15°C, the dehumidifying function will not work. Press the FUNCTION selector so that the display indicates (DEHUMIDIFY). The FAN SPEED is set at LOW or SILENT. Set the desired room temperature with the TEMPERATURE button (the display indicates the setting).
  • Page 17 COOLING OPERATION Use the device for cooling when the outdoor temperature is 21~ 43°C. If in doors humidity is very high (80%), some dew may form on the air outlet grille of the indoor unit. Press the FUNCTION selector so that the display indicates (COOL).
  • Page 18 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 FUNCTION selector so that the display indicates (FAN). Press the (FAN SPEED) button.
  • Page 19 HOW TO SET THE TIMER Time Set the (TIME) button. After you change the batteries; TIME OFF TIMER ON TIMER OFF-Timer Press the (OFF-TIMER) button. The (OFF) mark blinks on the display. RESERVE Start STOP CANCEL You can set the device to turn off at the preset time.
  • Page 20 Set the current time with the Press the (TIME) button again. Press the TIMER control button. The time indication starts lighting (TIME) button. instead of flashing. ● The time indication will disappear automatically in 10 second. ● To check the current time setting, press the (TIME) button twice.
  • Page 21 HOW TO SET THE SLEEP TIMER Set the current time at first if it is not set before (see the pages for setting the current time). Press the (SLEEP) button, and the display changes as shown below. Mode Indication 1 hour 2 hours 3 hours 7 hours...
  • Page 22 HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER Remove the cover as shown in the figure and take out the Push and pull to the old batteries. direction of arrow Install the new batteries. The direction of the batteries should match the marks in the case.
  • Page 23 THE IDEAL WAYS OF OPERATION Suitable Room Temperature Install curtain or blinds Warning It is possible to Freezing temperature reduce heat is bad for health and a entering the waste of electric power. room through windows. Ventilation Effective Usage Of Timer At night, please use the “OFF or ON timer Caution operation mode”, together with your wake up...
  • Page 24 FOR USER’S INFORMATION The Air Conditioner And The Heat Source In The Room Caution If the amount of heat in the room is above the cooling capability of the air conditioner (for example: more people entering the room, using heating equipments and etc.), the preset room temperature cannot be achieved.
  • Page 25 ATTACHING THE AIR CLEANSING FILTERS CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. Open the front panel. ● Pull up the front panel by holding it at both sides with both hands.
  • Page 26 MAINTENANCE CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. AIR FILTER Clean the air filter, as it removes dust inside the room. In case the air filter is full of dust, the air flow will decrease and the cooling capacity will be reduced.
  • Page 27 Washable Front Panel ● Remove the front panel and wash with clean water. Wash it with a soft sponge. After using neutral detergent, wash thoroughly with clean water. ● When front panel is not removed, wipe it with a soft dry cloth. Wipe the remote controller thoroughly with a soft dry cloth.
  • Page 28 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD Running the unit setting the operation mode to ● (FAN) and the fan speed to HI for about half a day on a fine day, and dry the whole of the unit.
  • Page 29 AFTER SALE SERVICE AND WARRANTY WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS. CONDITION CHECK THE FOLLOWING POINTS If the remote controller is ● Do the batteries need replacement? not transmitting a signal. ● Is the polarity of the inserted batteries correct? Remote controller display is dim or blank.) ●...

  • Page 30: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM – 29 –...
  • Page 31 CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR Handle Handle Air outlet Air suction grille Holes for anchor bolt (2-ø12) More than More than Fixing hole Service space Notch for anchor bolt (2-ø12 Notchs) – 30 –...

  • Page 32: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAS-S24H2A/RAC-S24H2 THERMOSTAT MODEL OPERATION MODE COOL HEAT 15.6 (60.1) 20.0 (68.0) INDICATION 15.3 (59.5) 20.7 (69.3) TEMPERATURE 23.6 (74.5) 28.0 (82.4) INDICATION °C (°F) 23.3 (73.9) 28.7 83.7) 31.6 (88.9) 36.0 (96.8) INDICATION 31.3 (88.3)
  • Page 33 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-S24H2 COMPRESSOR MODEL JU1013D5 PHASE SINGLE RATED VOLTAGE AC 220 ~ 240 V RATED FREQUENCY 50 Hz POLE NUMBER WHITE CONNECTION YELLOW 20°C 2M = 1.05 (68°F) RESISTANCE VALUE 75°C 2M = 1.28 (167°F) WHITE (U) RED (W) YELLOW (V)

  • Page 34: Wiring Diagram

    WIRING DIAGRAM MODEL RAS-S24H2A / RAC-S24H2 OUTDOOR UNIT CN10 COMPRESSOR INDOOR UNIT OUTDOOR TEMPERATURE THERMISTOR WHT YEL RED DEFROST THERMISTOR WHT YEL U V W CN14 CN14 SYSTEM POWER MODULE 2 THERMISTOR REACTOR C503 C501 C502 CN13 CN13 CN15 CN11...

  • Page 35: Circuit Diagram

    CIRCUIT DIAGRAM Remote Control – 34 –...
  • Page 36 CIRCUIT DIAGRAM – 35 –...
  • Page 37 CIRCUIT DIAGRAM MODEL RAC-S24H2 – 36–...

  • Page 38: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MAIN P.W.B. Marking on P.W.B. COMPONENT SIDE SOLDERING SIDE RECEIVING P.W.B. R621 TEMPORARY OPERATION Marking on P.W.B. 7 CN11 NORMAL LIGHT TEMPORARY RECEIVING UNIT SWITCH 2RZK81395A – 37 –...

  • Page 39: Block Diagram

    SPM2 Outdoor unit Terminal board Trip signal synthesis circuit Wireless receive LCD wireless circuit Filter. Room temperature Operation. thermistor Timer. Auto sweep motor for Heat exchanger Air deflector thermistor Electric Expansion valve Electric Expansion valve Temporary switch drive circuit Initial setting circuit Reset circuit –...

  • Page 40: Basic Mode

    OFF TIMER DURING OPERATION) (OFF ON TIMER DURING STOP) Operating mode Operating mode is judged by room temperature and outdoor temperature 1. Judging by outdoor temperature • Operating mode is judged by outdoor temperature If outdoor temperature ≥ 25°C or 21°C ≤ outdoor temperature <...
  • Page 41 Table 1 Mode data file RAS-S24H2A LABEL NAME VALUE –1 WMAX 6300 min WMAX2 6300 min –1 –1 WSTD 5900 min WJKMAX 4350 min –1 –1 WBEMAX 3600 min WSZMAX 3600 min –1 –1 CMAX 6300 min CSTD 5850 min –1...
  • Page 42 Table 2 TCMAX Temperature Calculated compressor difference 1.66 2600 2.00 2600 2.33 2600 2.66 3100 3.00 3100 3.33 3100 3.66 3600 4.00 3600 4.33 3600 4.66 4100 5.00 4100 6.00 4600 6.33 4600 6.66 5100 7.00 5100 7.33 5100 7.66 5600 8.00 5600...
  • Page 43 – 42 –...
  • Page 44 Dehumidifying Dehumidifying Sleep Operation Notes: (1) The sleep operation starts when the sleep key is pressed. (2) When the sleep key is set, the indoor fan is set to “sleep silent” (FDOY_M or AFDOY). (3) The indoor fan speed does not change even when the fan speed mode is changed. (4) If the set time is changed during sleep operation, all data including set temperature, time, etc.
  • Page 45 Table 3 TWMAX Calculated compressor Temperature difference 1.66 2300 2.00 2300 2.33 2300 2.66 2800 3.00 2800 3.33 2800 3.66 3300 4.00 3300 4.33 3300 4.66 3800 5.00 3800 6.00 4300 control by heat control by heat Control by 6.33 4300 Control by heat Control by heat...
  • Page 46 – 45 –...

  • Page 47: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAS-S24H2A / RAC-S24H2 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT SERVICE VALVE INDOOR UNIT (1/2) SINGLE-ENDED UNION (1/2) SUCTION TANK REVERSING VALVE ELECTRIC EXPANSION VALVE HEX THERMISTOR SERVICE VALVE (1/4) STRAINER SINGLE-ENDED UNION (1/4) STRAINER HEATING OUTDOOR UNIT...

  • Page 49: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION 1. Reset Circuit NORMAL : HI RESET : LO Microcomputer R522 IC521 Fig. 1-1 Voltage 5.0V Voltage supply to of IC521 Reset enter at 4.2V Reset release at 4.4V voltage 5.0V Voltage at pin of microcomputer Fig.
  • Page 50 2. Receiver Circuit R201 R611 RECEIVER I/P ▲ Microcomputer Fig. 2-1 The light receiver unit receives the infrared signal from the wireless remote control. The receiver amplifies ● and shapes the signal and outputs it. 3. Buzzer Circuit R219 Microcomputer Buzzer output Q722 Fig.
  • Page 51 4. Auto Sweep Motor Circuit Auto sweep motor for horizontal air deflectors IC711 Rotor Microcomputer Fig.4-1 Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig.4-2 are output from pins ● – of microcomputer. Horizontal air Microcomputer pins Step width deflectors: 10ms.
  • Page 52 5. Room Temperature Thermistor Circuit Fig. 5-1 shows the room temperature ● The voltage at depends on the room ● thermistor circuit. temperature as shown in Fig. 5-2. Room Microcomputer temperature thermistor R305 Room temp. input C302 R301 Fig. 5-1 Room temperature (˚C) Fig.
  • Page 53 7. Initial Setting Circuit (IC401) When power is supplied, the microcomputer reads the data in IC401 or IC402 (E PROM) and sets the ● preheating activation value and the rating and maximum speed of the compressor, etc. to their initial values.
  • Page 54 1. Power Circuit REACTOR SPM2 DIODE TERMINAL STACK 1 BOARD COIL POWER RELAY 25A FUSE NF COIL1 (D25VB60) SURGE- TB10 ABSORBER R007 R008 TB11 ICP RELAY TB12 C009 L001 L002 DIODE STACK 2 (RC2) R002 C012 C014 C007 C015 C013 C008 Fig.
  • Page 55 (3) Smoothing capacitor (C501, C502, C503) This smoothes (averages) the voltage rectified by the diode stacks. Smoothing Capacitors SPM2 Fig. 1-2 Be careful to avoid an electric shock as a ● high voltage is generated. Also take care not to cause a short-circuit through incorrect connection of test equipment terminals.
  • Page 56 2. Indoor/Outdoor Interface Circuit The interface circuit superimposes an interface signal on the DC 35V line supplied from the outdoor unit ● to perform communications between indoor and outdoor units. This circuit consists of a transmiting circuit which superimposes an interface signal transmit from the microcomputer on the DC 35V line and a transmiting circuit which detects the interface signal on the DC 35V line and outputs it to the microcomputer.
  • Page 57 Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with ● each other. R805 R813 R803 IC801 L801 R812 R810 IF transmit Q803 Q802 output (SDO) R804 R806 R811 C803 C802 C801 C804 MICROCOMPUTER Q801 R824 R826...
  • Page 58 0.7V Outdoor HIC Indoor microcomputer DC 35V line 100ms. 33ms. Leader 1 frame Fig. 2-2 Voltages Waveforms of indoor / Outdoor Microcomputers (Outdoor to Indoor Communications) Outdoor HIC Indoor microcomputer DC 35V line 4.95ms. 33ms. Transmit / receive 1 frame switching time Fig.
  • Page 62 DC 260-360V is input to system power module and system power module switches power supply current ● according to rotation position of magnet rotor. The switching order is as shown in Fig. 3-2. At point E: U + is ON, V – is ON (circuit in Fig. 3-1) At point F: U + is chopped (OFF), V –...
  • Page 63 System Power Module 2 260V-360V DC compressor U coil motor V coil — — — W coil DC current (Id) detection resistor Fig. 3-4 Power module circuit (U + is ON, V – is ON) Since current flows at point only when U+ transistor is ON, the current waveform at point becomes ●...
  • Page 64 4. Power Circuit for P.W.B. Fig. 4-1 shows the power circuit for P.W.B. and waveform at each point. ● Switching transformer (T1) C909 D907 Diode stack 2 R914 C910 (RC2) R902 I/F0V D908 L902 R915 R901 C901 R916 C911 D911 FM–15V D909 R917...
  • Page 65 (2) During ON The drain current at IC901 increases linearly. During this period, the gate voltage and current become ● constant because of the saturation characteristics of the transformer. (3) Shifting from ON to OFF This circuit applies a negative feedback signal from the 12V output. When the voltage across C919 ●...
  • Page 66 5. Reversing valve control circuit I/F 35V Reversing FUSE RESISTOR valve D702 PQ701 R703 Q701 Q705 R701 R219 R702 DC voltmeter or tester I/F 0V Fig. 5 – 1 Reversing valve control circuit can switch reversing valve ON/OFF according to instruction from indoor ●...
  • Page 67 6. Rotor magnetic pole position detection circuit System power module DC brushless motor for compressor 36 33 34 35 47 +12V C608 R604 C605 R605 C606 R606 C607 R607 No power Upper arm No power Lower arm No power supplied supplied supplied Induced voltage...
  • Page 69 [Low speed rotation mode] Fig. 7-2 [High speed rotation mode] Fig. 7-3 – 68 –...
  • Page 70 8. HIC and Peripheral Circuits Fig. 8-1 shows the micro computer and its peripheral circuits, Table 8-1, the basic operations of each ● circuit block, and Fig. 8-2, the system configuration. Detection Resistor DC Current SPM2 – HIC Direct Current DC260-380V SPM2 CN14...
  • Page 71 Reset Voltage Reset circuit Chopper Chopper Drive signal signal signal Drive Compressor Circuit Over-load external motor setting circuit DC 260V -360V Power module IP signal Peak current Current cut off circuit level Current amplified circuit Detection resistor DC current Fig. 8-2 The following describes the operations of each circuit in detail.
  • Page 72 (2) Overload control circuit (OVL control circuit) 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.
  • Page 73 Detection Resistor Direct Current DC Current DC 260-380V SPM2 CN14 CN13 MAIN P.W.B. C205 – R245 R248 Microcomputer R222 D104 R005 C218 R221 Fig. 8-6 Voltage at microcomputer pin Rotation speed of compressor Commanded rotation speed Actual rotation speed Deceleration Acceleration Deceleration Acceleration...
  • Page 74 R500, R253, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage (260- ● 380V) via HIC and applies correction to the overload set value so the DC current is low (high) when the DC voltage is high (low). (Since the load level is indicated by the DC voltage multiplied by DC current, R247, R248, R249 are provided to perform the same overload judgement even when the voltage varies.) Amplification : low...
  • Page 75 9. Temperature Detection Circuit O.H. thermistor Normal 2.7V or less Over heat 2.7V or more Reset 2.3V or less O.H. Microcomputer DEF. thermistor Normal 2.4V or more Over heat 2.4V or less Reset 2.9V or more DEF. Outdoor temperature thermistor Refer to the table 10-1 Outdoor CN10...
  • Page 76 10. Reset Circuit Main P.W.B Microcomputer R284 R289 – R252 JW10 RESET IC5 (1/2) R288 Fig. 10-1 The reset circuit initializes the microcomputer program when Power is “ON” or “OFF”. ● Low voltage at pin resets the microcomputer, and HI activates the microcomputer. ●...
  • Page 77 11. Outdoor DC Fan Motor control circuit. System power module Power supply for DC fan motor from smoothing capacitor in system power module RC Filter CN12 Main P.W.B 2A-FUSE Motor coil C101 FM-15V FM-15V R107 Q101 PWM control voltage D101 FG Pulse R101 R102...
  • Page 78 < Reference > When operation stop with LD301 blinks 12 times, it may be caused by faulty DC fan motor. ● In this case, please check CN6 and CN12 connection first. It makes Fan Motor Lock also if those ● connectors are in misconnection.
  • Page 79 12. Power Factor Control Circuit Power factor is controlled to almost 100%. (Effective use of power) With IC in ACT module, control is performed so that input current waveform will be similar to waveform of input voltage I (input current) input voltage V (input voltage) Effective...

  • Page 80: Service Call Q & A

    SERVICE CALL Q & A COOLING MODE The compressor has Check if the indoor heat If the air conditioner operates stopped suddenly during exchanger is frosted. in cooling mode when it is cooling operation. Wait for 3-4 minutes cold, the evaporator may get until it is defrosted.
  • Page 81 AUTO FRESH DEFROSTING Auto Fresh Defrosting is carried out : the After the ON/OFF button is pressed system checks the outdoor heat exchanger to stop heating, the outdoor unit is and defrosts it as necessary before stopping still working with the OPERATION operation.
  • Page 82 OTHERS The heat exchanger temperature The indoor fan varies among This is because the cool is sensed in the auto speed mode. high air flow, low air flow and wind prevention function When the temperature is low, the breeze in the auto fan speed is operating, and does fan speed varies among high air mode.

  • Page 83: Trouble Shooting

    TROUBLE SHOOTING PRECAUTIONS FOR CHECKING System power module 2 Power source DANGER – – – 1. Remember that the Compressor motor 0V line is biased to 155-170V in (0V) reference to the ground level. Indoor unit 2. Also note that it takes electric parts about 10 minutes DC35V...
  • Page 84 DISCHARGE PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT Caution Voltage of about 300-330V is charged between both ends of smoothing capacitors ● During continuity check for each part of circuit in indoor unit electrical parts, disconnect red/gray WARNING ●...
  • Page 85 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Timer lamp See “Troubleshooting when the timer lamp Does the timer lamp on the indoor unit blink? blinks”. Remove the terminal cover and check the voltage between terminal (C) and terminal (D) Does the operation lamp on the indoor unit Terminal D Terminal C...
  • Page 86 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Blinking of Timer lamp Reason for indication Possible cause Reversing valve defective (1) Reversing valve defective When the indoor heat exchanger (2) Heat exchanger thermistor dis- temperature is too low in the...
  • Page 87 SELF-DIAGNOSIS LIGHTING MODE DD0002206A – 86 –...
  • Page 88 CHECKING INDOOR UNIT ELECTRICAL PARTS 1. Power does not come on (no operation) Is AC 220-240V AC being generated Is DC 35V being generated between Check AC outlet and breaker, and between terminals L and N on the terminals C and D on the terminal repair any defective part.
  • Page 89 2. Outdoor unit does not operate (but receives remote infrared signal) – 88 –...
  • Page 90 3. Only indoor fan does not operate (other is normal) 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) – 89 –...
  • Page 91 6. Check the main P.W.B (power circuit) – 90 –...
  • Page 92 CHECKING THE REMOTE CONTROLLER – 91 –...
  • Page 98 POWER CIRCUIT Phenomenon 1 <Rotation speed does not increase> Recheck cord, etc. of the Is the DC voltage at least 350V? system power module. If they are disconnected, connect them securely. Is the OVL lamp lit? If the lamp is lit, it does not If abnormality continues, replace the system indicate fault, but the unit...
  • Page 99 (JUDGING BETWEEN GAS LEAKAGE AND CHECKING THE REFRIGERATING CYCLE COMPRESSOR DEFECTIVE) 1. Troubleshooting procedure (No operation, No heating, No cooling) Lighting mode Blinks Blinks Blinks Blinks Blinks Blinks Connect U,V,W phase leads to the Self- 2 times 3 times 4 times 5 times 6 times 8times...
  • Page 100 HOW TO CHECK SYSTEM POWER MODULE Checking system power module using tester Set tester to resistance range (X 100) If indicator does not swing in the following conductivity check, the system power module is normal. (In case of 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.
  • Page 101 HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT 1. Turn off the power supply to outdoor unit and then turn on again. 2. Remove the electrical box cover. LD303 (red) will light and the unit will operate in the forced cooling mode at this time. Never operate the unit for more than 5 minutes.
  • Page 102 SYSTEM POWER MODULE DIAGNOSIS Circuit diagram of Collector the device (excepting the reflux diode) BASE Emitter Circuit diagram of the module – Terminals symbol mark of the module See next page for measuring value using tester – L2 L1 – 101 –...

  • Page 103: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAS-S24H2A – 102 –...
  • Page 104 PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL : RAC-S24H2 – 103 –...
  • Page 105 THE UPDATED PARTS LIST FOR THIS MODEL IS AVAILABLE ON ESTA - 104 -...
  • Page 106 HITACHI RAS-S24H2A/RAC-S24H2 SM0419...

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