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Hitachi RAS25YH4 Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
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
DECEMBER 2003
RAS25YH4
RAS35YH4
RAC25YH4
RAC35YH4
INDOOR UNIT
RAS25YH4
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
780
H
280
D
205
(kg)
ROOM AIR CONDITIONER
INDOOR UNIT + OUTDOOR UNIT
Hitachi Household Appliance (Wuhu) Co., Ltd.
RAS25YH4 / RAC25YH4
RAS35YH4 / RAC35YH4
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 4
HOW TO USE ----------------------------------------------------------------------- 6
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 25
MAIN PARTS COMPONENT --------------------------------------------------- 27
WIRING DIAGRAM ---------------------------------------------------------------- 29
CIRCUIT DIAGRAM --------------------------------------------------------------- 31
PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 37
BLOCK DIAGRAM ----------------------------------------------------------------- 41
BASIC MODE ----------------------------------------------------------------------- 43
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 55
DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 56
TROUBLE SHOOTING ----------------------------------------------------------- 87
PARTS LIST AND DIAGRAM ------------------------------------------------ 115
DC INVERTER (WALL TYPE)
OUTDOOR UNIT
RAC25YH4
1 PHASE, 50Hz, 230V
560 (155 ~ 1,080)
2.86
2.50 (0.90 ~ 3.10)
8,530 (3,070 ~ 10,575)
770 (115 ~ 1,120)
3.72
3.40 (0.90 ~ 4.40)
11,601 (3,070 ~ 15,695)
750
548
288
9.5
35
SM0001
CONTENTS
INDOOR UNIT
OUTDOOR UNIT
RAS35YH4
RAC35YH4
1 PHASE, 50Hz, 230V
950 (155 ~ 1,300)
4.35
3.50 (0.90 ~ 4.00)
11,942 (3,070 ~ 13,650)
980 (115 ~ 1,300)
4.49
4.20 (0.90 ~ 5.00)
14,331 (3,070 ~ 17,745)
780
750
280
548
205
288
9.5
35
After installation

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  • Page 1: Table Of Contents

    14,331 (3,070 ~ 17,745) 11,601 (3,070 ~ 15,695) DIMENSIONS (mm) NET WEIGHT (kg) After installation SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ROOM AIR CONDITIONER INDOOR UNIT + OUTDOOR UNIT Hitachi Household Appliance (Wuhu) Co., Ltd. DECEMBER 2003...
  • Page 2 SAFETY DURING REPAIR WORK 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. 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 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). Object parts (1) Micro computer (2) Integrated circuits (IC)
  • 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 operation or stopping the running, 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-25YH4 RAC-25YH4 MODEL RAS-35YH4 RAC-35YH4 FAN MOTOR 40 W PWM DC35V FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR — EU1011DF COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) 3.0A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR 450NR...
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  • Page 8: How To Use

    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 9 PRECAUTIONS DURING OPERATION • Do not use any conductor as fuse wire, this could cause fatal accident. PROHIBITION • During thunder storm, disconnect the plug top or turn off the circuit breaker. WARNING “OFF” • Spray cans and other combustibles should not be located within a meter of the air outlets of both indoor and outdoor units.
  • Page 10 NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT Air filter To prevent dust from coming into the indoor unit. (Refer page 20) Front panel Indoor unit indicators Light indicator showing the operating condition. (Refer page 9) Horizontal deflector Vertical deflector (Air Outlet) (Refer page 19) Remote controller...
  • Page 11 NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT INDICATIONS FILTER LAMP (Green) When the device is operated for a total of about 200 hours, the FILTER lamp lights indicates that it is time to clean the filter.The lamp goes out when the POWER SWITCH “...
  • Page 12 NAMES AND FUNCTIONS OF EACH PART 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, in some cases, the control signal may not be received. This unit can be fixed on a wall using the fixture provided.
  • Page 13 VARIOUS FUNCTIONS I 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. When you switch on the circuit breaker, the operation will be automatically restarted with previous operation mode and airflow direction.
  • Page 14 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 -10°C of the outdoor temperature.
  • Page 15 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 automatically. The FAN SPEED button does not work.
  • Page 16 COOLING OPERATION Use the device for cooling when the outdoor temperature is 22-42°C. If humidity is very high (over 80%) indoors, some dew may form on the air outlet grille of the indoor unit. Press the FUNCTION selector so that the display indicates (COOL).
  • Page 17 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 18 HOW TO SET THE TIMER Set the current month and day Time, Day, Month TIME, DAY, with the TIMER control button. MONTH (current After you change the time, day, month) batteries; OFF TIMER ON TIMER Press the (OFF-TIMER) OFF-Timer button. The (OFF) mark blinks RESERVE on the display.
  • Page 19 Set the Set the current time with Press the (TIME) (TIME) button. the TIMER control button. button again. The time • The time indication will disappear automatically in 10 indication star ts lighting seconds. instead of flashing. • To check the current time setting, press the (TIME) button twice.
  • Page 20 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 21 ADJUSTING THE AIR DEFLECTORS Adjustment of the conditioned air in the upward and downward directions. The horizontal air deflector is automatically set to the proper angle suitable for each operation. The deflector can be swung up and down continuously and also set to the desired angle using the “...
  • Page 22 MAINTENANCE CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. 1. AIR FILTER When the filter indicator lamp comes on, be sure to clean the filter. By doing so, the power rates are saved.
  • Page 23 2. CLEANING OF FRONT PANEL • Remove the front panel and wash with clean water. Wash it with a soft sponge. After using neutral detergent, wash thoroughly with clean water. • When front panel is not removed, wipe it with a soft dry cloth.
  • Page 24 INFORMATION CAPABILITIES Heating Capability CAUTION • This room air conditioner utilizes a heat pump system that absorbs exterior heat and brings it into a room to be heated. As the ambient Do not use a stove temperature gets lower, heating capability will also lower. In such a other situation, the inverter work to increase compressor rpm to keep the h i g h t e m p e ra t u r e...
  • Page 25 REGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS EVERY EITHER HALF YEARLY OR YEARLY. CONTACT YOUR SALES AGENT SHOULD YOU NEED ANY HELP. Check to see if the unit’s earth line has been con- nected correctly. If the earth line is disconnected or faulty, unit failure or WARNING electric shock hazard may result.
  • Page 26 Noise of the ventilation fan sucking in air present in the drain hose and blowing out dehumidifying water that had accumulated in the condensed water collector. For Perking noise details, consult your sales agent. Operation noise changes due to power variations according to room temperature Changing operation noise changes.

  • Page 27: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAS-25YH4, RAS-35YH4 INDOOR UNIT Top air suction grill Mounting plate Front panel Cabinet Discharge grill Horizontal air diflector (190) Drain When piping is drawn from the left side, exchange the drain hose for the drain cap 17.5 Drain hose Drain cap connection port...
  • Page 28 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAC-25YH4, RAC-35YH4 OUTDOOR UNIT Handle Handle Air outlet Air Suction grill Holes for anchor bolt (2 – ø12 x 6 slots for ø8.0 bolt) Notch for anchor bolt (for 2 – ø8.0 bolt) Drain hole Fixing hole Drain hole More than...

  • Page 29: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAS-25YH4, RAS-35YH4 THERMOSTAT MODEL OPERATION MODE COOL HEAT 16.7 (62.1) 18.7 (65.7) INDICATION 16.0 (60.8) 19.3 (66.7) TEMPERATURE 24.7 (76.5) 26.7 (80.1) INDICATION °C (°F) 24.0 (75.2) 27.3 (81.1) 32.7 (90.9) 34.7 (94.5) INDICATION 32.0 (89.6) 35.3 (95.5)
  • Page 30 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-25YH4, RAC-35YH4 ITEM COMPRESSOR TYPE EU1011DF POWER SOURCE DC 270 ~ 320 V OUTPUT 800W WHITE WINDING YELLOW RESISTANCE 25°C U–V 1.090 U–W 1.090 W–U 1.090 (Ω) WHITE COMPRESSOR YELLOW FRONT SIDE OF OUTDOOR UNIT CAUTION When the refrigerating cycle has been operated for a long time with the capillary tubes clogged or crushed or with too little refrigerant, check the color of the refrigerating machine oil inside the compressor.

  • Page 31: Wiring Diagram

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  • Page 33: Circuit Diagram

    CIRCUIT DIAGRAM Remote Control Key matrix table Output Input Door open Start/Stop Operation selection Fan speed selection Automatic swing Door shut Start/Stop Automatic swing – – SEG5 SEG20 Door open On timer Hour up Hour down • present time SEG0 SEG19 SEG1 SEG18...
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  • Page 39: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAS-25YH4, RAS-35YH4 MAIN P.W.B. MARKING ON P.W.B. COMPONENT SIDE SOLDERING SIDE – 37 –...
  • Page 40 MODEL RAS-25YH4, RAS-35YH4 RECEIVING P.W.B. MARKING ON P.W.B. COMPONENT SIDE SOLDERING SIDE MODEL RAC-25YH4, RAC-35YH4 POWER P.W.B. MARKING ON P.W.B. COMPONENT SIDE – 38 –...
  • Page 41 MODEL RAC-25YH4, RAC-35YH4 MAIN P.W.B. MARKING ON P.W.B. COMPONENT SIDE SOLDERING SIDE – 39 –...

  • Page 43: Block Diagram

    BLOCK DIAGRAM MODEL RAS-25YH4 / RAC-25YH4 RAS-35YH4 / RAC-35YH4 INDOOR UNIT OUTDOOR UNIT Outdoor DC fan motor Power source 1ø 50Hz 230V HARMONICS POWER POWER RELAY RECTIFIER IMPROVEMENT SWITCH CIRCUIT Inrush current DC compressor Protection circuit motor Rotor magnetic pole position detection circuit Wireless receive Remote controller...

  • Page 45: Basic Mode

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  • Page 47 Table 1 Mode data file RAS-25YH4 RAS-35YH4 LABEL NAME VALUE 3800 min –1 4500 min –1 WMAX 3800 min –1 4500 min –1 WMAX2 –1 –1 3150 min 3750 min WSTD 2500 min –1 2800 min –1 WBEMAX 3300 min –1 3800 min –1...
  • Page 49 Table 1 Thermo judgment Item Temperature Room Thermo judgment (ON) 30°C CLMXTP temperature Thermo judgment (OFF) 32°C Thermo judgment (ON) 32°C Outdoor temperature Thermo judgment (OFF) 33°C Table 2 Compressor rpm Temperature Calculated difference compressor rpm (with shift value) 1.66°C –1 2500 min button...
  • Page 51 Cooling Sleep Operation Dehumidifying Operation Room temperature 7 hr 1 hr Set to 7 hours Sleep button Operation lamp Timer lamp Remote control (Sleep) ON See basic Start Stop button operation Indoor fan Sleep Lo Outdoor fan Horizontal air Shut deflector Horizontal Facing down...
  • Page 53 Table 3 Compressor rpm Basic Heating Operation Temperature Calculated difference compressor rpm (with shift value) 1900 min –1 1.66°C –1 2400 min 2.00°C Heating set temperature 2900 min –1 2.33°C (remote control set temperature (+)) 3400 min –1 2.66°C 3900 min –1 3.00°C Dash period...
  • Page 55 Heating Sleep Operation Reversing Valve Defrosting Preheating released Sleep button Reversing valve (cooling "on" model) 2min. 30sec. Sleep Lo Notes: (1) The defrosting inhibit period is set as shown in the diagram below. When defrosting has finished once, the inhibit period is newly set, based on the outdoor temperature when the compressor was started. During this period, the defrost signal is not accepted.

  • Page 57: Refrigerating Cycle Diagram

    Silencer Service valve Single-ended union Reversing valve Charge port Silencer Electric Expansion valve Single-ended Service valve union Strainer Strainer Silencer Service valve Reversing Single-ended union valve Charge port Silencer Electric Expansion valve Single-ended Service valve union Strainer Strainer – 55 –...

  • Page 58: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAS-25YH4, RAS-35YH4 1. Reset Circuit The reset circuit initializes the microcomputer program when power is ON or OFF Low voltage at pin (7) resets the microcomputer and Hi activates the microcomputer When power “ON” 5V voltage rises and reaches 4.4V, pin (1) of IC521 is set to “Hi”. At this time the microcomputer starts operation.
  • Page 59 2. Receiver Circuit Q141 L201 Fig.2-1 IRR (light receiver unit) receives the infrared signal from the wireless remote controller. The receiver amplifie and shapes the signal and outputs it. 3. Buzzer Circuit Fig.3-1 Buzzer circuit When the buzzer sounds, an approx 3.9kHz square signal is output from buzzer output pin (30) of the microcomputer.
  • Page 60 4. Auto Sweep Motor Circuit Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig.4-2 are output from pin (15) ~ (18) of microcomputer. As the microcomputer’s outputs change as shown in Fig.4-2, the coils of the auto sweep motor is excite to turn the rotor.
  • Page 61 5. 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 62 7. Fan Motor Drive Circuit Micro computer DC fan motor output Fan motor DC fan motor Speed feedback Fig. 7-1 Voltage at point A Waveform T1 = Low speed T2 = High speed Voltage at point B Waveform Voltage at point C Waveform Fig.
  • Page 63 I RAC-25YH4, 35YH4 1. The electrical parts for the outdoor unit is composed of two P.W.B (a power P.W.B. and main P.W.B.) and a harmonics improvement circuit as shown in Fig. 1-1. • Main P.W.B This P.W.B. is equipped with the rectification diode, DC fan motor control circuit and the circuits around the micro computer which take various controls.
  • Page 64 2. Power circuit This circuit is to convert the power from AC which is provided from the terminal A and B to DC voltage And produces an AC current which does not exceed the harmonic amplitude limit of the IEC61000-3-2. When the compressor is stopped, the AC voltage becomes about 300 V and while the compressor operates, it is about 280 V.
  • Page 65 (3) C021 and C022 This smoothes the voltage rectified for operating the compressor. When the input voltage is taken for the sine wave as shown in the top of Fig. 2-4, it is rectified by the DB2 and becomes the waveform as shown in the middle of Fig.
  • Page 66 3. Indoor/Outdoor Interface Circuit The interface circuit superimposes an interface signal on the DC 35V line to perform communications between indoor and outdoor units. This circuit consists of a transmitting circuit which superimposes an interface signal transmit from the microcomputer on the DC 35V line and a circuit which detects the interface signal on the DC 35V line.
  • Page 67 Fig. 3-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other. – 65 –...
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  • Page 71 4. IPM (Intelligent Power Module) • Fig.4-1 shows the intelligent power module and its peripheral circuit. The three transistors on the positive e side are called the upper arm, and the three transistors on the negative d side, the lower arm. Fig.
  • Page 72 Intelligent power module switches power supply current according to position of the compressor motor rotor. The switching order is as shown in Fig. 4-2. At point E: U+ is ON, V is ON (circuit in Fig. 4-1) At point F: U+ is chopped (OFF), V is ON (circuit in Fig. 4-4) Fig.
  • Page 73 – Fig. 4-4 Power module circuit (U is ON, V is ON) Since current flows at point (B) only when U+ transistor is ON, the current waveform at point (B becomes intermittent waveform as shown in Fig. 4-3. Since current at point (B) is approximately proportional to the input current of the air conditioner, input current is controlled by using DC current (Id) detection resistor.
  • Page 74 • IPM drive circuit The inverter driving device (IGBT) and the drive circuit are built in the IPM. The IPM receives the signal from the microcomputer and convert it to 0 – 15 V signal to drive the IGBT. When the unit operates at low speed, a chopper signal is emitted from the micro computer as shown in Fig.
  • Page 75 5. Power Circuit for P.W.B • Fig. 5-1 shows the power circuit for P.W.B. • In the power circuit for P.W.B., power supply for microcomputer, peripheral circuits, and IPM driver circuit and, as well as DC 35V, are produced by switching power circuit. •...
  • Page 76 • The voltage specification of the power circuit is as follows. <Check points> Output Voltage Main load Measuring points Potential failure modes spec. – 11-13V MAIN P.W.B. (CN3, CN4) R701 (“12V” display) R006 (“0V” display) The unit won’t operate C21 (“12V” display) J27, J30 MAIN P.W.B.
  • Page 77 6. Microcpomputer's Peripheral Circuits 6-1. 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 78 Power Reset output Reset Main P.W.B. Fig. 6-2 (1). IS OVL The voltage amp. circuit amplifies the DC current level detected by the detection transformer CT1. Receiving this, the microcomputer converts it to a digital signal and compares it with the internal data to judge whether or not overload control is required.
  • Page 79 R003,R004,R608,R613, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage (260-380V) and applies correction to the overload set value so the DC current will be low when the DC voltage is high. (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.) Fig.
  • Page 80 6-2. Reset Circuit MAIN P.W.B. RESET OUT. Fig. 6-7 The reset circuit initializes the microcomputer program when Power is “ON” from “OFF” Low voltage at pin (48) resets the microcomputer, and HI activates the microcomputer Fig. 6-7 shows the reset circuit and Fig. 6-8 shows waveform at each point when power is turned on and off.
  • Page 81 7. Temperature Detection Circuit MAIN P.W.B. C304 C303 C302 Fig. 7-1 The Over heat thermistor circuit detects the temperature at the surface of the compressor head, the Defrost. thermistor circuit detects the defrosting operation temperature. A thermistor is a negative resistor element which has the characteristics that the higher (lower) the temperature, the lower (higher) the resistance.
  • Page 82 8. Reversing valve control circuit Power P.W.B. MAIN P.W.B. Reversing valve Micro computer DC voltmeter or multimeter Fig. 8-1 Reversing valve control circuit will switch reversing valve ON/OFF according to instruction from indoor microcomputer depending on the operation condition shows in Table 8-1. Voltage at Q701 (between Collector and Emittor) in each operation condition is approximately as shown in Table 8-1 when measured by multimeter.
  • Page 83 9. Electric expansion valve control circuit POWER P.W.B MAIN P.W.B CN15 Microcpmputer Valve4 Valve3 Electric Valve2 expansion valve Valve1 Fig. 9-1 • To drive the expansion valve, use the B-12 V output. Use a 4-phase coil and feed power to the phases 1 and 2, then switch over the filed poles to control the opening of the valve.
  • Page 84 10. Outdoor DC Fan Motor control circuit This model uses DC Fan Motor which has a controller circuit built in the Motor This DC Fan Motor will rotate by control voltage apply to Vsp input. (Voltage range: 1.7 to 7V DC Vsp high : Faster ;...
  • Page 85 < 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. DC Fan Motor has broken invites 1A Fuse burned.

  • Page 86: Service Call Q & A

    SERVICE CALL Q & A Model RAS-25YH4 / RAC-25YH4 RAS-35YH4 / RAC-35YH4 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 87 AUTO FRESH DEFROSTING After the ON/OFF button is pressed Auto Fresh Defrosting is carried out : the 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 88 When the “Sleep” timer is set during (1) The temperature arrives at the preset indoor operation, temperature and the air conditioner unit is (1) The indoor fan won’t rotate. temporarily stopped. Within about 3 minutes, (No air comes from the unit) the fan starts rotation.

  • Page 89: Trouble Shooting

    TROUBLE SHOOTING RAS-25YH4, 35YH4 PRECAUTIONS FOR CHECKING Power inlet WARNING Remember that voltage of 175 V is applied to the 0V line on the P.W.C or the like as shown in the right diagram. Always keep your hands and metallic things away WARNING from the cabinet.
  • Page 90 DISCHARGE, PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT WARNING Caution • Voltage of about 350 V is charged between the terminal of smoothing capacitors (400µF x 2) • During continuity check for each circuit part of the outdoor unit, be sure to discharge the smoothing capacitors.
  • Page 91 STRUCTURE OF AN INDOOR UNIT ELECTRIC PARTS RAS-25YH4, 35YH4 ELEC. COVER FIXTURE SCREW FIXTURE SCREW Removing electrical parts When installing the parts, use 1. Remove the electrical parts cover. caution not to pinch any code 2. Remove the connectors from the CN1 (heat exchange between the part and cabinet.
  • Page 92 Other Cautions (1) Cautions concerning ICP (IC Protector) 1. Use due caution for short circuit in servicing. Short circuit will open the ICP immediately. 2. When the ICP opens, remove the cause of this phenomenon and replace the ICP. If the remedy is improper, the ICP may open again. 35V line ICP2 Indoor unit fan motor...
  • Page 93 THE SUPPORT FUNCTION OF FAILURE DIAGNOSIS Function Name Description Self-diagnosis indication function • The “timer lamp” indicates a mode of failure detected <Indicating a failure on the indoor on the indoor or outdoor unit side by blinking unit side> frequency. •...
  • Page 94 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Model RAS-25YH4, RAS-35YH4 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAS-25YH4, RAS-35YH4 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...
  • Page 95 SELF-DIAGNOSIS LIGHTING MODE MODEL RAC-25YH4, RAC-35YH4 – 93 –...
  • Page 96 OUTDOOR UNIT Remove the compressor connector. 1/ 2/ IPM (Intelligent Power Module) 3/ Service Switch 4/ Self-Diagnosis Lamp • Check the drive If your first attempt With the unit set in the operating circuit (IMP) using fails, wait 3 minutes state, press the start/stop the PRD checker.
  • Page 97 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING Trouble shoot according to the Is the indoor unit "timer lamp" blinking? self-diagnosis lighting mode. Open the indoor unit and check the voltage Run the unit using the following remote controller settings: between pins Nos.1 and 3 of CN3 on the In the cooling season, set the temperature to 16ßC in the cooling indoor unit control P.W.B.
  • Page 98 CHECKING THE INDOOR UNIT ELECTRICAL PARTS 1. Power does not come on (no operation) Is AC230V being generated between Is AC230V being generated at AC Check AC outlet and breaker, and terminals A and B on the indoor unit outlet? repair any defective part.
  • Page 99 2. Indoor fan does not operate (others are normal) Can the fan be stopped by remote The microcomputer fan PWM Replace the microcomputer. control? output (at pin 24) is 1 5V. Replace the fan motor. Replace the microcomputer. Perform final operation check. 3.
  • Page 100 4. Check the control P.W.B. (power circuit) Is 35V or 20V being output Check to see if the connection cables are at pin 5 relative to 0V at pin disconnected or reversed. 3 of CN3? If normal, check the outdoor unit P.W.B. Is 12V or 7V being output Is ICP1 normal? at (+) relative to 0V at (-) of...
  • Page 101 CHECKING THE REMOTE CONTROLLER Is battery polarity correct? Install the battery in the correct polarity. Is the battery check sign + – Replace the battery. flashing? Turn on an AM radio, bring the remote control switch within 15 cm of the radio, and press the ON/OFF button.
  • Page 102 WARNING PRECAUTIONS FOR SERVICING Be sure that the power switch is turned off or the power cable is disconnected before servicing. Removing the PWBs. System Configuration of Outdoor Unit Electrical Parts The outdoor unit electrical parts consist of two PWBs as shown in the figure. <Control P.W.B.
  • Page 103 [C. Power Factor Improvement capacitor] Designed to improve power factor. To replace the capacitor, remove the power P.W.B. and then: 1. Remove two screws fastening the capacitor seat. 2. Slide the capacitor seat in the direction of the arrow. Sliding Direction –...
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  • Page 111 (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 112 HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT MODEL RAC-25YH4, RAC-35YH4 1. Turn off the power switch. 2. Remove the electrical box cover. 3. Turn on the power switch 4. After waiting for 30 seconds, push the service switch for a second. LD303 (red) will light and the unit will operate in the forced cooling mode at this time.
  • Page 113 IPM (Intelligent Power Module) DIAGNOSIS Circuit diagram of Collector the device RASF Emitter Circuit diagram of the module Terminals symbol mark of the module * See next page for measuring value using multimeter – 111 –...
  • Page 114 – 112 –...

  • Page 115: Procedure For Disassembly And Reassembly

    Procedure for Disassembly and Reassembly INDOOR UNIT RAS-25YH4, RAS-35YH4 1. Front Panel 3. Main P.W.B. and Reception/Indication (1)Pull up the washable panel by holding it at both P.W.B lower sides with both hands. (1)Remove each connector from the lead wire. (2)Remove the four P.W.B supports from the main P.W.B..
  • Page 116 4. Tangential air flow fan and fan motor OUTDOOR UNIT RAC-25YH4, RAC-35YH4 (1)Remove two screws locking the drain pan. 1. Electrical parts (2)Press to lower the hook at the center of the (1)Remove the service value cover lock screws unit a little and pull the claw forward to remove and lower the cover to remove it.

  • Page 117: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL: RAS-25YH4, RAS-35YH4 15 16 – 115 –...
  • Page 118 INDOOR UNIT PARTS NO. RAS-25YH4 RAS-35YH4 Q'TY PARTS NAME HWRAS-25YH4901 CABINET HWRAS-25YH4902 VERTICAL AIR DEFLECTOR-L HWRAS-25YH4903 VERTICAL AIR DEFLECTOR-R HWRAS-25YH4904 FAN MOTOR 25W 1.1kg HWRAS-25YH4905 ANTI VAIBRATION BUSHING HWRAS-25YH4907 TANGENTIAL AIR FLOW FAN HWRAS-25YH4908 FAN SUPPORT ASS'Y HWRAS-25YH4909 FAN COVER HWRAS-25YH4910 FAN MOTOR SUPPORT HWRAS-25YH4911...
  • Page 119 OUTDOOR UNIT MODEL: RAC-25YH4, RAC-35YH4 – 117 –...
  • Page 120 OUTDOOR UNIT PARTS No. RAC-25YH4 RAC-35YH4 Q'TY PARTS NAME HWRAC-25YH4901 BASE HWRAC-25YH4902 COMPRESSOR 1000W 9.7kg HWRAC-25YH4903 COMPRESSOR RUBBER HWRAC-25YH4904 PUSH NUT HWRAC-25YH4905 CONDENSER HWRAC-25YH4906 REVERSING VALVE HWRAC-25YH4907 SERVICE VALVE ASS'Y HWRAC-25YH4908 ELECTRIC EXPAN. VALVE HWRAC-25YH4909 SOUND PROOF COVER ASS'Y HWRAC-25YH4910 O.L.R COVER HWRAC-25YH4911 O.H THERMI.
  • Page 121 HITACHI RAS25YH4 / RAC25YH4 AW SM0001 RAS35YH4 / RAC35YH4...

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