Hitachi RAS-50YH4 Service Manual
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Hitachi RAS-50YH4 Service Manual

Hitachi RAS-50YH4 Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
RAS-50YH4
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
JANUARY 2005
RAC-50YH4
(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-50YH4/RAC-50YH4
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 5
HOW TO USE ------------------------------------------------------------------------ 7
CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 30
MAIN PARTS COMPONENT --------------------------------------------------- 32
WIRING DIAGRAM ----------------------------------------------------------------- 35
CIRCUIT DIAGRAM ---------------------------------------------------------------- 39
PRINTED WIRING BOARD LOCATION DIAGRAM ---------------------- 42
BLOCK DIAGRAM ------------------------------------------------------------------ 46
BASIC MODE ------------------------------------------------------------------------ 48
REFRIGERATING CYCLE DIAGRAM ---------------------------------------- 60
AUTO SWING FUNCTION ------------------------------------------------------ 61
DESCRIPTION OF MAIN CIRCUIT OPERATION ------------------------ 62
TROUBLE SHOOTING ------------------------------------------------------------ 96
PARTS LIST AND DIAGRAM ------------------------------------------------- 118
DC INVERTER (WALL TYPE)
INDOOR UNIT
OUTDOOR UNIT
RAS-50YH4
RAC-50YH4
1 PHASE, 50 Hz, 230V
1,780 (155 ~ 2,200)
7.80
5.00 (0.90 ~ 5.20)
17,060
1,970 (115 ~ 2,200)
8.65
6.50 (0.90 ~ 8.10)
22,180
780
850
650
280
205
298
9.5
50
SM0226
CONTENTS

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Summary of Contents for Hitachi RAS-50YH4

  • Page 1: Table Of Contents

    SM0226 RAS-50YH4/RAC-50YH4 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ------------------------------------------------------------------- 5 HOW TO USE ------------------------------------------------------------------------ 7 CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 30 MAIN PARTS COMPONENT --------------------------------------------------- 32 WIRING DIAGRAM ----------------------------------------------------------------- 35 CIRCUIT DIAGRAM ---------------------------------------------------------------- 39...
  • 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 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-50YH4 RAC-50YH4 MODEL FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR – JU1013D COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) 3.0A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR 450NR NOISE SUPPRESSOR THERMOSTAT...
  • Page 7 Figure showing the Installation of Indoor and Outdoor unit. The Length of Indoor Unit Power Cord The installation height of indoor unit must be about 2.3m or more. 0.9m about 1.6m CAUTION Do not alter the power cord. Direction of Piping above 50mm Be sure to Horizontally...
  • Page 8 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 ● 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 10 (Refer page 6) OUTDOOR UNIT DRAIN PIPE Condensed water drain to outside. CONNECTING CORD AIR INLET (BACK, LEFT SIDE) AIR OUTLET MODEL NAME AND DIMENSIONS MODEL WIDTH (mm) HEIGHT (mm) DEPTH (mm) RAS-50YH4 RAC-50YH4 – 9 –...
  • Page 11 INDOOR UNIT INDICATORS 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 POWER SWITCH set to OFF and ON again. OPERATION LAMP TEMPORARY This lamp lights during operation.
  • Page 12 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 13 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 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 -15°C of the outdoor temperature. Press the FUNCTION selector so that the display indicates (HEAT).
  • 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 10-43°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 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 Time, Day, Month Set the current month and TIME, DAY, day with the TIMER control After you change the MONTH button. batteries; (current time, day, month) OFF TIMER RESET ON TIMER OFF-Timer Press the (OFF-TIMER) button.
  • Page 19 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 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 Explanation of the sleep timer The device will control the FAN SPEED and room temperature automatically so as to be quiet and good for people’s health. You can set the sleep timer to turn off after 1, 2, 3 or 7 hours. The FAN SPEED and room temperature will be controlled as shown below.
  • Page 22 ADJUSTING THE AIR DEFLECTOR 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 RESET up and down continuously and also set to the desired angle using the “...
  • Page 23 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 24 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 25 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 26 ATTACHING THE AIR CLEANSING AND DEODORIZING 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 27 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 28 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 29 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 Run the unit by setting the operation mode to ● (COOL), the temperature to 32°C and the fan speed to HI for about half a day on a fine day, and dry the whole of the unit.
  • Page 30 AFTER SALE SERVICE AND WARRANTY WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS. CONDITION CHECK THE FOLLOWING POINTS Is the fuse all right? ● Is the voltage extremely high or low? ● When it does not operate ● Is the circuit breaker “ON”? Was the air filter cleaned? ●...
  • Page 31 -50YH4...

  • Page 32: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR MODEL RAC-50YH4 Handle Handle Air suction Air outlet grille Holes for anchor bolt (2-ø12) More than More than Fixing hole Service space Notch for anchor bolt (2-ø12 Notchs) – 31 –...

  • Page 33: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAS-50YH4 THERMOSTAT MODEL OPERATION MODE COOL HEAT 16.7 (62.1) 20.0 (68.0) INDICATION 16.0 (60.8) 20.7 (69.3) TEMPERATURE 24.7 (76.5) 28.0 (82.4) INDICATION °C (°F) 24.0 (75.2) 28.7 83.7) 32.7 (90.9) 36.0 (96.8) INDICATION 32.0 (89.6)
  • Page 34 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-50YH4 COMPRESSOR MODEL JU1013D PHASE SINGLE RATED VOLTAGE AC 220 ~ 230 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 YELLOW CAUTION...

  • Page 36: 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...
  • Page 37 CIRCUIT DIAGRAM MODEL RAS-50YH4...
  • Page 38 CIRCUIT DIAGRAM MODEL RAC-50YH4 – 41 –...

  • Page 39: Printed Wiring Board Location Diagram

    PRINGTED WIRING BORD LOCATION DIAGRAM MODEL RAS-50YH4 MAIN P.W.B. MARKING ON P.W.B. COMPONENT SIDE SOLDERING SIDE – 42 –...
  • Page 40 MODEL RAS-50YH4 RECEIVING P.W.B. MARKING ON P.W.B. COMPONENT SIDE SOLDERING SIDE – 43 –...
  • Page 41 MODEL RAC-50YH4 MAIN P.W.B. Marking on P.W.B – 44 –...
  • Page 42 RAS-50YH4 / RAC-50YH4 Power source SPM2 1ø, 50Hz, 230V 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...

  • Page 43: Basic Mode

    BASIC M O D E Operation mode Dehumidifying (dehumidifying operation by the Cooling Heating Auto function select button only, not including that engaged by the dehumidify button) Basic operation of start/stop switch Start Stop Start Stop Start/stop switch Operation tamp Start/stop switch Operation tamp Cancel switch...
  • Page 44 Table 1 Mode data file RAS-50YH4 LABEL NAME VALUE 6200 min –1 WMAX 6250 min –1 WMAX2 5200 min –1 WSTD –1 WBEMAX 2600 min 5700 min –1 CMAX 5800 min –1 CMAX2 5200 min CSTD –1 3550 min –1...
  • Page 45 Δ Table 2 TCMAX Temperature Calculated difference compressor rpm 1.66 2265 min –1 2435 min –1 2.33 2600 min –1 2.66 2765 min –1 2935 min –1 3.33 3100 min –1 3.66 3265 min –1 3435 min –1 4.33 3600 min –1 4.66 3765 min...
  • Page 46 New Cool Rhythm Cooling Sleep Operation Room temperature Final set temperature Minimum Minimum Minimum Minimum (Cooling/dehumidifying set 5min. 5min. Minimum 5min. 5min. 5min. 5min. 5min. 5min. Minimum 5min. 5min. 5min. temperature (+) sleep shift) Final set temperature (Cooling/dehumidifying set temperature (Cooling/dehumidifying set (temperature set by remote 0.5hr...
  • Page 47 Delay 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 for 5 minutes and ON for 1 minute. (3) When the operation is started by the themostat turning ON, the start of the indoor fan is delayed 32 seconds after the start of compressor operation.
  • Page 48 Δ Table 3 TWMAX Basic Heating Operation Temperature Calculated difference compressor rpm 1.66 1965 min –1 2135 min –1 2.33 2300 min –1 2.66 2465 min –1 Heating set temperature (remote control set temperature (+)) 2635 min –1 3.33 2800 min –1 Dash period 18˚C...
  • Page 49 Reversing Valve Defrosting Heating Sleep Operation 0.5hr 6.5hr Set to 7 hours Sleep key Operation lamp [SLEEP] on the remote controller is lit Timer lamp Indoor fan Silent See basic Sleep operation See basic operation Outdoor fan TDF 431 Facing up Vertical air 413 TDF421 1 min...

  • Page 50: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM S 50YH4 / RAC-50YHH4...
  • Page 51 – 61 –...

  • Page 52: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAS-50YH4 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 55 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 57 Model RAC-50YH4 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...
  • Page 58 (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 59 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 60 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 R826 R824...
  • Page 61 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 – 72 –...
  • Page 63 Compressor minimum rotation speed (4 MSB) Compressor minimum rotation speed (3) Compressor minimum rotation speed (2) Compressor minimum rotation speed (1) Compressor minimum rotation speed (0 LSB) Fan-7-step request OVL up 15/20(A) Actual compressor rotation speed (5 MSB) Compressor command speed (7 MSB) Actual compressor rotation speed (4) Compressor command speed (6) Actual compressor rotation speed (3)
  • Page 64 3. Power Module Circuit – 74 –...
  • Page 65 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 66 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 67 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 68 (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 69 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 70 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 R607 C607 No power Upper arm No power Lower arm No power supplied supplied supplied Induced voltage...
  • Page 71 7. Drive Circuit Fig. 7-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration. – 81 –...
  • Page 72 [Low speed rotation mode] Fig. 7-2 [High speed rotation mode] Fig. 7-3 – 82 –...
  • Page 73 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 74 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 75 (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 76 Detection Resistor DC Current Direct Current DC 260-380V SPM2 CN14 CN13 MAIN P.W.B. C205 – R245 R248 Microcomputer R222 D104 R005 R221 C218 Fig. 8-6 Voltage at microcomputer pin Rotation speed of compressor Commanded rotation speed Actual rotation speed Deceleration Acceleration Deceleration Acceleration...
  • Page 77 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 78 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 79 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 80 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 81 < 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 82 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 83: Service Call Q & A

    SERVICE CALL Q & A Model RAS-50YH4 / RAC-50YH4 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 84 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 85 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 86: Trouble Shooting

    TROUBLE SHOOTING Model RAS-50YH4 / RAC-50YH4 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.
  • Page 87 DISCHARGE PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT...
  • Page 88 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Model RAC-50YH4 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) Is approx.
  • Page 89 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Model RAS-50YH4 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAS-50YH4 Blinking of Timer lamp Reason for indication Possible cause Reversing valve defective...
  • Page 90 SELF-DIAGNOSIS LIGHTING MODE MODEL: RAC-50YH4 – 100 –...
  • Page 91 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 92 2. Outdoor unit does not operate (but receives remote infrared signal) Set to room temperature 16°C in the cooling mode or to 32°C in the heating mode, and press the start/stop button. Remove the outdoor unit cover and electrical parts cover, and check self- Check the room temperature diagnosis lamp LD301.
  • Page 93 3. Only indoor fan does not operate (other is normal) Can the fan be stopped by The microcomputer fan PWM Replace the microcomputer. remote control? output (pin) is “Hi” Replace the indoor fan motor. Replace the microcomputer. Perform final operation check. 4.
  • Page 94 6. Check the main P.W.B (power circuit) Replace ICP2. Check if Is DC 35V being output Is ICP2 normal? shorting has occurred in fan between cathode and Normal if it is less than 1Ω. motor circuit and 35V anode of D101? Blown (open) if it is 1Ω...
  • Page 95 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 96 CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAC-50YH4 – 106 –...
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  • Page 101 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, indicate fault, but the unit replace the system...
  • Page 102 (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 103 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 104 HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT MODEL RAC-50YH4 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 105 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 – 115 –...
  • Page 106 Procedure for Disassembly and Reassembly INDOOR UNIT RAS-50YH4 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 107 4. Tangential air flow fan and fan motor (1)Remove two screws locking the drain pan. (2)Press to lower the hook at the center of the unit a little and pull the claw forward to remove the drain pan. Fig. 5 (3)Remove the screws from the upper and lower bearing covers.
  • Page 109 25Y 4...

  • Page 110: Parts List And Diagram

    PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL : RAC-50YH4...
  • Page 111 MODEL RAC-50YH4 PART N0. Q’TY / UNIT PARTS NAME RAC-50YH4 PMRAC-50NH4 BASE PMRAC-50NH4 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-19SH4 REVERSING VALVE PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAC-50NH4 VALVE (2S) PMRAC-50NH4 VALVE (4S) PMRAC-40CNH2 THERMISTOR (OH) PMRAC-25NH4 OVERHEAT THERMISTOR SUPPORT PMRAC-25NH4 OVERLOAD RELAY COVER PMRAC-40CNH2...
  • Page 112 HITACHI RAS-50YH4/RAC-50YH4 SM0226 Printed in Malaysia...

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Rac-50yh4

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