Hitachi RAD-50DH7A Service Manual
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Hitachi RAD-50DH7A Service Manual

Room air conditioner
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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

ROOM AIR CONDITIONER

APRIL 2008
RAD-50DH7A
RAD-60DH7A
RAD-70DH7A
RAC-50DH7
RAC-60DH7
RAC-70DH7
INDOOR UNIT
RAD-50DH7A
1 Ø, 50 Hz, 220-240V
(W)
1,400 (200 ~ 2,100)
(A)
(kW)
5.00 (0.90 ~ 6.00)
(B.T.U./h)
17,070 (3,073 ~ 20,490)
(W)
1,590 (200 ~ 2,200)
(A)
(kW)
6.00 (0.90 ~ 7.00)
(B.T.U./h)
20,490 (3,073 ~ 23,901)
W
900
H
270
720
D
(kg)
35
INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
PM
RAD-50DH7A/RAC-50DH7
RAD-60DH7A/RAC-60DH7
RAD-70DH7A/RAC-70DH7
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ----------------------------------------------------- 4
HOW TO USE ---------------------------------------------------------- 6
MAIN PARTS COMPONENT ------------------------------------- 26
WIRING DIAGRAM -------------------------------------------------- 28
CIRCUIT DIAGRAM ------------------------------------------------- 29
BLOCK DIAGRAM --------------------------------------------------- 35
BASIC MODE --------------------------------------------------------- 39
REFRIGERATING CYCLE DIAGRAM ------------------------- 52
TROUBLE SHOOTING --------------------------------------------- 83
PARTS LIST AND DIAGRAM ----------------------------------- 103
(DUCTING TYPE)
OUTDOOR UNIT
INDOOR UNIT
RAC-50DH7
RAD-60DH7A
1 Ø, 50 Hz, 220-240V
1,870 (200 ~ 2,500)
6.40 ~ 5.90
8.55 ~ 7.90
6.00 (0.90 ~ 7.00)
20,490 (3,073 ~ 23,901)
2,130 (200 ~ 2,600)
7.30 ~ 6.70
9.75 ~ 9.00
7.30 (0.90 ~ 8.00)
24,920 (3,073 ~ 27,315)
850
900
800
270
298
720
55
35
NO. 0411E
CONTENTS
OUTDOOR UNIT
INDOOR UNIT
OUTDOOR UNIT
RAC-60DH7
RAD-70DH7A
RAC-70DH7
1 Ø, 50 Hz, 220-240V
2,530 (200 ~ 2,920)
11.60 ~ 10.70
7.10 (0.90 ~ 8.00)
24,240 (3,073 ~ 27,310)
2,340 (200 ~ 3,100)
10.70 ~ 9.80
8.00 (0.90 ~ 9.00)
27,310 (3,073 ~ 30,730)
850
900
800
270
298
720
55
35
After installation
850
800
298
55

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Summary of Contents for Hitachi RAD-50DH7A

  • Page 1: Table Of Contents

    NO. 0411E RAD-50DH7A/RAC-50DH7 RAD-60DH7A/RAC-60DH7 SERVICE MANUAL RAD-70DH7A/RAC-70DH7 TECHNICAL INFORMATION REFER TO THE FOUNDATION MANUAL FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ----------------------------------------------------- 4 HOW TO USE ---------------------------------------------------------- 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM ------- 23 MAIN PARTS COMPONENT ------------------------------------- 26 WIRING DIAGRAM -------------------------------------------------- 28...
  • Page 2 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). 2.
  • Page 3 (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 4 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 recommended to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 5: Specifications

    SPECIFICATIONS RAD-50DH7A RAD-60DH7A MODEL RAC-50DH7/RAC-60DH7/RAC-70DH7 RAD-70DH7A 56 W 80 W FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR – COMPRESSOR JU1015D4 COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR 3.15A FUSE (MICRO COMPUTER CIRCUIT) POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH...
  • Page 6 Figure showing the installation of Indoor and Outdoor unit CAUTION Install the indoor unit with a proper clearance around it for operation and maintenance working space. In case that the ceiling board can not be detected for servicing, prepare a service access door below the indoor unit for removing the indoor unit.

  • Page 7: Names And Functions Of Each Part

    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) RAD-50DH7A / RAD-60DH7A / RAD-70DH7A RAC-50DH7 / RAC-60DH7 / RAC-70DH7 – 6 –...
  • Page 8 Please note: On switching on the equipment, particularly when the room light is dimmed, a slight brightness fluctuation may occur. This is of no consequence. The conditions of the local Power Supply Companies are to be observed. Note Avoid to use the room air conditioner for cooling operation when the outside temperature is below 21°C (70°F).

  • Page 9: Safety Precaution

    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 10 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 11 NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT I This controls the operation function and timer setting of the room air conditioner. START/STOP Button Use this button to select the operating mode. Every time you press it, the mode will change from (AUTO) to (HEAT) to (DEHUMIDIFY) and to...

  • Page 12: Automatic Operation

    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. (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.

  • Page 13: Heating Operation

    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 14: Dehumidifying Operation

    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 15: Cooling Operation

    COOLING OPERATION Use the device for cooling when the outdoor temperature is –10 ~ 43°C. If indoor 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 16 TIMER RESERVATION I ON Timer and OFF Timer are available. I Operation stop at setting time OFF Timer Reservation OFF TIME setting Select the OFF TIME by pressing the (OFF) Button. Setting time will change according to the below sequence when you press the button. 0.5 hour interval 1 hour interval 0 .
  • Page 17 HOW TO SET THE SLEEP TIMER Mode Indication 1 hour 2 hours 3 hours 7 hours Sleep timer Sleep timer off Sleep Timer: The device will continue working for the designated number of hours and then turn off. Press the SLEEP button, indoor unit will produce a beep. The timer information will be displayed on the remote controller.
  • Page 18 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. NOTE If you set the sleep timer after the off or on-timer has been set, the sleep timer becomes effective instead of the off or on-timer set earlier.

  • Page 19: How To Use

    CIRCUIT BREAKER When you do not use the room air conditioner, set the circuit breaker to “OFF”. HOW TO USE THE AIR CONDITIONER EFFECTIVELY 1. An average room temperature setting is probably the best for you as well as being economical. Excessive cooling or heating is not recommended for health reasons.

  • Page 20: Suitable Room Temperature

    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 21 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 22: Air Filter

    MAINTENANCE WARNING Before cleaning, stop unit operation with the remote controller and turn off the circuit breaker. CAUTION Do not expose the unit to water as it may cause an electric shock. For cleaning inside the air conditioner, consult your sales agent. Avoid using detergent when cleaning the heat exchanger of the indoor unit.

  • Page 23: Regular Inspection

    REGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS BY QUALIFIED SERVICE PERSONAL EITHER EVERY HALF YEARLY OR YEARLY. CONTACT YOUR SALES AGENT OR SERVICE SHOP. Is the earth line disconnected or broken? Is the mounting frame seriously affected by rust and is the outdoor unit tilted or unstable? Is the plug of power line firmly plugged into the socket? (Please ensure no loose contact between them).

  • Page 24: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAD-50DH7A RAD-60DH7A RAD-70DH7A Unit : mm Wired remote controller Note: 1. Servicing space of 100mm or more is required on the left and right sides of the indoor unit and also 50mm or more space is required above the unit 2.
  • Page 25 MOUNTING HOLE DIMENSION MODEL RAD-50DH7A RAD-60DH7A RAD-70DH7A SIDE VIEW Refrigerant Gas Pipe Connection Refrigerant Liquid Pipe Connection AIR FLOW AIR FLOW DIRECTION DIRECTION Ø Ø Drain Pipe Connection TOP VIEW 980 (for Suspension Bot) Ø 107.2 102.2 Ø – 24 –...
  • Page 26 MODEL RAC-50DH7 RAC-60DH7 RAC-70DH7 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) – 25 –...

  • Page 27: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT (Room Temperature Thermistor) Thermostat Specifications MODEL RAD-50DH7A/RAD-60DH7A/RAD-70DH7A 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)
  • Page 28 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-50DH7/RAC-60DH7/RAC-70DH7 COMPRESSOR MODEL JU1015D4 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 = 1.268 (167°F) W/S (RED) V/R (YELLOW) U/C (WHITE)
  • Page 29 – 28 –...

  • Page 30: Circuit Diagram

    CIRCUIT DIAGRAM Wired Remote Control – 29 –...
  • Page 31 CIRCUIT DIAGRAM MODEL RAD-50DH7A, RAD-60DH7A, RAD-70DH7A – 31 –...
  • Page 32 CIRCUIT DIAGRAM MODEL RAC-50DH7/RAC-60DH7/RAC-70DH7 – 33 –...
  • Page 33 – 35 –...
  • Page 34 Table 1 Mode data file RAD-50DH7A RAD-60DH7A RAD-70DH7A LABEL NAME VALUE 5800 min –1 WMAX –1 WMAX2 5800 min –1 WSTD 4950 min CMAX 5200 min –1 –1 CSTD 5000 min –1 WMIN 1500 min –1 CMIN 1600 min STARTMC...
  • Page 35 29. 66 Heating – 39 –...
  • Page 36 ∆ 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 37 Cooling Sleep Operation Set to 7 hours Sleep key Operation lamp Timer lamp Indoor fan See basic operation Lo (sleep) Outdoor fan Maximum speed Notes: The sleep operation starts when the sleep key is pressed. When the sleep key is set, the maximum compressor speed is limited, and the indoor fan is set to “sleep Lo”. The indoor fan speed does not change even when the fan speed mode is changed.
  • Page 38 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 39 ∆ Table 3 TWMAX Basic Heating Operation Temperature Calculated difference compressor rpm 1.66 1965 min –1 2135 min –1 2.33 2300 min –1 Heating set temperature 2.66 2465 min –1 (remote control set temperature (+)) 2635 min –1 3.33 2800 min –1 Dash period 18˚C...
  • Page 40 1 min WMIN Notes: The sleep operation starts when the sleep key is pressed. When the sleep key is set, the maximum compressor speed is limited to WSTD+2000/2, and the indoor fan is set to “sleep Lo”. If the operation mode is changed during sleep operation, the changed operation mode is set and sleep control starts.

  • Page 41: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAD-50DH7A/RAC-50DH7 RAD-60DH7A/RAC-60DH7 COOLING, DEHUMIDIFYING, DEFROSTING INDOOR UNIT OUTDOOR UNIT COND S-TANK COMP REVERSING VALVE 4S VALVE SILENCER EXPANSION VALVE STRAINER STRAINER 2S VALVE HEATING INDOOR UNIT OUTDOOR UNIT COND S-TANK COMP REVERSING VALVE 4S VALVE SILENCER...
  • Page 42 REFRIGERATING CYCLE DIAGRAM MODEL RAD-70DH7A/RAC-70DH7 COOLING, DEHUMIDIFYING, DEFROSTING INDOOR UNIT OUTDOOR UNIT COND S-TANK COMP REVERSING VALVE 5S VALVE SILENCER EXPANSION VALVE STRAINER STRAINER 2S VALVE HEATING INDOOR UNIT OUTDOOR UNIT COND S-TANK COMP REVERSING VALVE 5S VALVE SILENCER EXPANSION VALVE STRAINER STRAINER 2S VALVE...
  • Page 43 – 53 –...

  • Page 44: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAD-50DH7A, RAD-60DH7A, RAD-70DH7A 1. Reset Circuit 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. 1-2 The reset circuit initializes the microcomputer program when power is ON or OFF.
  • Page 45 2. Buzzer Circuit R722 Microcomputer Buzzer output Q722 Fig. 2-1 Buzzer Circuit When the buzzer sounds, an approx. 3.9kHz square signal is output from buzzer output pin of the microcomputer. After the amplitude of this signal has been set to 12Vp-p by a transistor, it is applied to the buzzer.
  • Page 46 3. Initial Setting Circuit (IC401) When power is supplied, the microcomputer reads the data in IC401 (E PROM) and sets the preheating activation value and the rating and maximum speed of the compressor, etc. to their initial values. Data of self-diagnosis mode is stored in IC401; data will not be erased even when power is turned off. Microcomputer C401 External ROM...
  • Page 47 5. Heat exchanger temperature thermistor circuit Heat exchanger Micro computer temperature thermistor R307 Heat exchanger C301 temperature R308 input Fig. 5-1 The circuit detects the indoor heat exchanger temperature and controls the following. (1) Low-temperature defrosting during cooling dehumidifying operation. The voltage at A depends on the heat exchanger temperature as shown in Fig.
  • Page 48 7. Drain pump trial run switch R533 R534 Drain pump Microcomputer trial run SW (normally, Hi) This switch forcibly turns the drain pump on. When the drain pump trial run switch is turned on, the timer indicator will blink seven times, and no remote signal will be accepted. 8.
  • Page 49 10. Indoor Fan Motor Feedback Circuit JOINT CONNECTOR 340V IC201 PC201 R501 Q502 ZD201 PC202 Q503 R234 R233 Q204 Fig. 10-1 <Exp. of circuit wave> JOINT CONNECTOR Fig. 10-2 motor will receive signal thru Joint Connector with VDC (Motor Drive Voltage), VCC (Motor Controller Power Supply), VSC (RPM Instruction) motor WCC return the FG sinal under frequency RPM.
  • Page 50 11. Wired remote control receiver circuit — Wired input CN18 R611 L550 C551 C550 R771 R770 C611 L551 Micro computer Wired remote control PC101 C771 C770 GRN2 The signal from wired remote control is send to micro computer pin no 13 by using photo coupler (PC101). L550, L551, C770 and C771 act as a filter to reduce the noise from the wired remote control.
  • Page 51 1. Power Circuit RAC-50DH7, RAC-60DH7, RAC-70DH7 REACTOR SPM2 Power P.W.B. DIODE TERMINAL STACK 1 BOARD 25A FUSE POWER RELAY COIL NF COIL1 (D25VB60) R002 R003 INRUSH CURRENT RELAY TB10 SURGE ABSORBER TB11 R001 TB12 VARISTOR2 L007 GRN1 C103 C017 L005 R009 GRN2 C014...
  • Page 52 (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 53 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 54 Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other. R813 R812 C802 Q803 R810 IF transmit output (SDO) C804 R811 Micro computer C821 R821 IF receive input (SDI) I/F 0V C822 D101 Terminal board Indoor P.W.B.
  • Page 55 0.7V Base of outdoor P.W.B Q801, Q802 , Q803 Outdoor micro computer lndoor micro computer SDO Pin SDI Pin 35V DC line 33ms. 100ms. 1 frame Leader Fig. 2-2 Voltages Waveforms of indoor / Outdoor Micro computers (Outdoor to Indoor Communications) Base of outdoor P.W.B Q801, Q802 Outdoor micro computer lndoor micro computer SDO Pin...
  • Page 56 3. Power Module Circuit – 66 –...
  • Page 57 DC 320-360V is input to power module and 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 58 System Power Module 320-360V DC compressor motor U coil — — V coil — W coil DC current (Id) detection resistor Fig. 3-4 System Power module circuit (U + is OFF, V – is ON) Since current flows at point B only when U+ transistor and V – transistor is ON, the current waveform at point B becomes intermittent waveform as shown in Fig.
  • Page 59 4. Power Supply Circuit Fig. 4-1 shows the power circuit. Fig. 4-1 Power circuit for P.W.B. There are two switching power supply in Power PWB. Switching power supply 1 is generating the secondary power for control circuits and DC35V indoor unit. Switching power supply performs voltage conversion effectively by switching transistor IC1 to convert DC330V to high frequency of approximately 20kHz to 200kHz.
  • Page 60 (4) During OFF While IC1 is on, the following energy charges the primary windings of the transformer: Energy=LI /2. Here, L : Primary inductance I : Current when IC1 is off This energy discharges to the secondary windings during power off. That is, C707-C710, C718 is charged according to the turn ratio of each winding.
  • Page 61 6. Rotor magnetic pole position detection circuit lnverter DC brushless motor for compressor R502 +12V R505 R504 R503 R501 R604 R603 R601 R602 R605 C605 R606 C606 R607 R608 R609 R610 C607 R611 Fig. 6-1 Rotor magnetic pole position detection circuit When the DC brushless motor is rotated, it also operates as power generator, generating reverse electromotive force according to number of rotations.
  • Page 62 7. Peripheral circuit of microcomputer Fig. 7-1 shows the microcomputer and its peripheral circuits. Table 7-1, the basic operations of each circuit block, and Fig. 7-2, the system configuration. Outdoor Microcomputer Q205 (AX-6S00) Q212 R366 Reset C224 R345 terminal DC current Detection resistor R245 IP cutter...
  • Page 63 8. 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 64 9. Reset Circuit Outdoor Q205 Microcomputer Q212 (AX-6V01) R366 Reset C224 R345 Fig. 9-1 Reset circuit performs initial setting of the microcomputer program when power is turned on. Microcomputer resets program with reset voltage set to Lo, to enable operation at Hi level. Fig.
  • Page 65 10. Temperature Detection Circuit The outdoor units (this model) provides with the outdoor temperature thermistor, DEF (defrost) 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-70YHA1/RAS-80YHA1, and their roles and temperature measuring points are shown as Table 10-1.
  • Page 66 Table 10-1 Name and Role of each thermistor Name Connector No Measuring Point Role OH thermistor Compressor head The thermistors decide the defrost DEF thermistor Heat exchanger operation during heating combined the data of the outside temperature and its data. Outdoor temperature is used to Outdoor temperature Outside temperature...
  • Page 67 When the connectors of the thermistors are disconnected or the thermistors is open or short, LD301 (red) lights and LD302 (red) blinks so that they indicate troubled parts. Combinations of LD301 and LD302 are set up for indicating troubled thermistors. The correspondences between the number of blink time and troubled parts are shown as Table 10-3. Look in the table (LD301 and LD302 blink) for troubled parts, and if the disconnections of them are checked out, they are replaced.
  • Page 68 Electric expansion valve Table 11-1 The electric expansion valve is driven by DC 12V. Power is supplied to 1 or 2 phases of 4-phase winding to switch magnetic pole of winding in order to control opening degree. Relationship between power switching direction of phase and open/close direction is shown below. When power is supplied, voltages at pins 4 to 1 of CN15 are about 0.9V;...
  • Page 69 12. Power Factor Control Circuit Power factor is controlled by 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 70: 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 71 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 72 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 73: 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 74 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 lead wire connected from diode stack to system power module (SPM2) to prevent secondary trouble.
  • Page 75 TROUBLESHOOTING WHEN TIMER LAMP BLINKS Model RAD-50DH7A, RAD-60DH7A, RAD-70DH7A Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAD-50DH7A, RAD-60DH7A, RAD-70DH7A <Remark> If using wired remote controller, electrical cover have to be opened so that timer lamp at indoor p.w.b can be seen as Fig.
  • Page 76 SELF-DIAGNOSIS LIGHTING MODE MODEL RAC-50DH7, RAC-60DH7, RAC-70DH7 – 86 –...
  • Page 77 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Unit does not operate Open electrical cover of indoor unit. Timer lamp See Troubleshooting when the timer lamp Does the timer lamp on the indoor unit blink? blinks . Refer page 85. Remove the terminal cover and check the voltage between terminal (C) and terminal (D) Insert and fix the...
  • Page 78 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 79 2. Outdoor unit does not operate (but receives remote infrared signal) – 89 –...
  • Page 80 3. Only indoor fan does not operate (other is normal) 4. All systems stop from several seconds to several minutes after operation is started (all indicators are also off) Disconnect joint connector at indoor fan motor and set to the fan mode again. –...
  • Page 81 5. Check the main P.W.B (power circuit) Is DC 35V being output D701 and C701 may be Is DC 35V being output between cathode and defective at terminals C and D? mode of D701 Is DC 12V being supplied There is a defective between accross the control side the 12V output of switching (coil terminal) of interface relay...
  • Page 82 CHECKING THE REMOTE CONTROLLER – 92 –...
  • Page 83 CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS – 93 –...
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  • Page 88 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 89 (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 90 SYSTEM POWER MODULE DIAGNOSIS Circuit diagram of Collector the device (excepting the BASE reflux diode) Emitter Circuit diagram of the module — Terminals symbol mark of the module See next page for measuring value using tester — L2 L1 – 100 –...
  • Page 91 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 DANGER If inner circuit of system power module is disconnected (open), the indicator of tester will not swing and this may...

  • Page 92: How To Operate The Outdoor Unit Independently

    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 93: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAD-50DH7A/RAD-60DH7A/RAD-70DH7A – 103 –...
  • Page 94 MODEL RAD-50DH7A PART N0. Q’TY / UNIT PARTS NAME PMRAD-50DH7 CYCLE ASSY PMRAD-50DH7 DRAIN PAN ASSY PMRAD-50DH7 FLOAT SWITCH PMRAD-50DH7 FAN MOTOR PMRAD-50DH7 FAN CASING PMRAD-50DH7 PMRAD-50DH7 BAND (L) PMRAD-50DH7 BAND (R) PMRAD-50DH7 DRAIN PUMP PMRAD-50DH7 FILTER PMRAD-50DH7 FILTER PLATE...
  • Page 95 MODEL RAD-60DH7A PART N0. Q’TY / UNIT PARTS NAME PMRAD-50DH7 CYCLE ASSY PMRAD-50DH7 DRAIN PAN ASSY PMRAD-50DH7 FLOAT SWITCH PMRAD-50DH7 FAN MOTOR PMRAD-50DH7 FAN CASING PMRAD-50DH7 PMRAD-50DH7 BAND (L) PMRAD-50DH7 BAND (R) PMRAD-50DH7 DRAIN PUMP PMRAD-50DH7 FILTER PMRAD-50DH7 FILTER PLATE PMRAD-50DH7 THERMISTOR SUPPORT PMRAD-60DH7A R01...
  • Page 96 MODEL RAD-70DH7A PART N0. Q’TY / UNIT PARTS NAME PMRAD-70DH7 CYCLE ASSY PMRAD-50DH7 DRAIN PAN ASSY PMRAD-50DH7 FLOAT SWITCH PMRAD-50DH7 FAN MOTOR PMRAD-50DH7 FAN CASING PMRAD-50DH7 PMRAD-50DH7 BAND (L) PMRAD-50DH7 BAND (R) PMRAD-50DH7 DRAIN PUMP PMRAD-50DH7 FILTER PMRAD-50DH7 FILTER PLATE PMRAD-50DH7 THERMISTOR SUPPORT PMRAD-70DH7A R01...
  • Page 97 PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL : RAC-50DH7/RAC-60DH7/RAC-70DH7 – 107 –...
  • Page 98 MODEL RAC-50DH7 PART N0. Q’TY / UNIT PARTS NAME PMRAC-50YHA1 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-70YHA CONDENSER PMRAC-50YHA1 REVERSING VALVE PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAC-50NH4 VALVE (4S) PMRAC-50NH4 VALVE (2S) PMRAC-80YHA THERMISTOR (OH) PMRAC-25NH4 OVERHEAT THERMISTOR SUPPORT PMRAC-25NH4 OVERLOAD RELAY COVER PMRAC-70YHA THERMISTOR (DEFROST)
  • Page 99 MODEL RAC-60DH7 PART N0. Q’TY / UNIT PARTS NAME PMRAC-50YHA1 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-70YHA CONDENSER PMRAC-50YHA1 REVERSING VALVE PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAC-50NH4 VALVE (4S) PMRAC-50NH4 VALVE (2S) PMRAC-80YHA THERMISTOR (OH) PMRAC-25NH4 OVERHEAT THERMISTOR SUPPORT PMRAC-25NH4 OVERLOAD RELAY COVER PMRAC-70YHA THERMISTOR (DEFROST)
  • Page 100 MODEL RAC-70DH7 PART N0. Q’TY / UNIT PARTS NAME PMRAC-50YHA1 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-70YHA CONDENSER PMRAC-50YHA1 REVERSING VALVE PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAC-80YHA VALVE (5S) PMRAC-50NH4 VALVE (2S) PMRAC-80YHA THERMISTOR (OH) PMRAC-25NH4 OVERHEAT THERMISTOR SUPPORT PMRAC-25NH4 OVERLOAD RELAY COVER PMRAC-70YHA THERMISTOR (DEFROST)
  • Page 101 HITACHI RAD-50DH7A/RAC-50DH7 PM NO. 0411E RAD-60DH7A/RAC-60DH7 RAD-70DH7A/RAC-70DH7 Printed in Malaysia...

This manual is also suitable for:

Rac-50dh7Rad-60dh7aRac-60dh7Rad-70dh7aRac-70dh7

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