Hitachi RAS-70YH5 Service Manual
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Hitachi RAS-70YH5 Service Manual

Hitachi RAS-70YH5 Service Manual

Room air conditioner
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HITACHI

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 2005
0305E cover
RAS-70YH5
RAC-70YH5
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)

ROOM AIR CONDITIONER

INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
1
PM
RAS-70YH5 / RAC-70YH5
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 4
HOW TO USE ------------------------------------------------------------------------ 6
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 28
MAIN PARTS COMPONENT --------------------------------------------------- 30
WIRING DIAGRAM ---------------------------------------------------------------- 32
CIRCUIT DIAGRAM --------------------------------------------------------------- 33
PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 39
BLOCK DIAGRAM ----------------------------------------------------------------- 42
BASIC MODE ----------------------------------------------------------------------- 43
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 57
AUTO SWING FUNCTION ------------------------------------------------------ 58
DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 59
TROUBLE SHOOTING ----------------------------------------------------------- 86
PARTS LIST AND DIAGRAM ------------------------------------------------- 106
DC INVERTER (WALL TYPE)
INDOOR UNIT
RAS-70YH5
1 PHASE, 50 Hz, 240V
2,670
11.2
7.10
24,240
2,800
11.80
8.30
28,330
1030
295
191
12
4/1/06, 10:47 AM
NO. 0305E
CONTENTS
RAC-70YH5
850
800
298
52
After installation

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Summary of Contents for Hitachi RAS-70YH5

  • Page 1: Table Of Contents

    NO. 0305E HITACHI RAS-70YH5 / RAC-70YH5 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ------------------------------------------------------------------- 4 HOW TO USE ------------------------------------------------------------------------ 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 28 MAIN PARTS COMPONENT --------------------------------------------------- 30 WIRING DIAGRAM ---------------------------------------------------------------- 32...
  • Page 2 SAFETY DURING REPAIR WORK 1. In order to disassemble and repair the unit in question, be sure to disconnect the power cord plug from the power outlet before starting the work. 2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and the replacement must be effected in correct manner according to the instructions in the Service Manual of the unit.
  • Page 3 WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS 1. Scope The standards provide for items to be generally observed in carrying and handling semiconductors in relative manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal goods such as rejected goods being returned).
  • Page 4 (6) Use a three wire type soldering iron including a grounding wire. Metal plate (of aluminium, stainless steel, etc.) Working table Resistor of 1 M (1/2W) Staple Earth wire Bare copper wire (for body earth) Fig. 3. Grounding of the working table Soldering iron Grounding wire...
  • Page 5 CAUTION In quiet or stopping operation, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally, but this noise is not abnormal for the operation. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 6: Specifications

    SPECIFICATIONS MODEL RAC-70YH5 RAS-70YH5 40 W PWM DC35V FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR – JU1015D3 COMPRESSOR COMPRESSOR MOTOR CAPACITOR YES (INTERNAL) OVERLOAD PROTECTOR OVERHEAT PROTECTOR 3.0A FUSE (for MICROPROCESSOR) 3.15A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH...
  • Page 7 Figure showing the installation of Indoor and Outdoor unit The installation height of indoor unit must be 2.3m or more in a non public area. CAUTION above 50mm Be sure to above 100mm completely seal any gap with putty. above 100mm 2,300mm or more Plug The indoor piping should be...

  • Page 8: 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 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: Names And Functions Of Each Part

    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-70YH5 1030 RAC-70YH5 – 8 – 0305E Pg 06-15 4/1/06, 10:48 AM...
  • Page 11 INDOOR UNIT INDICATORS OPERATION LAMP This lamp lights during operation. HITACHI TIMER LAMP This lamp lights when the timer is working. 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.
  • 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: 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 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

    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

    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

    COOLING OPERATION Use the device for cooling when the outdoor temperature is 22-42°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

    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: To Set The Timer

    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 (TIME) button. TIMER control button. The time indication starts lighting 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. NOTE If date or current time is not set, sleep timer can not be set.

  • Page 22: 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 room through waste of electric power. windows. Ventilation Effective Usage Of Timer At night, please use the “sleep timer operation Caution mode”, together with your wake up time in the...
  • Page 23 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 24 ATTACHING THE AIR CLEANSING FILTERS CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. Open the front panel. Pull up the front panel by holding it at both sides with both hands.
  • Page 25 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 26 CLEANING OF FRONT PANEL Wipe it with a soft dry cloth. When it is excessively dirty, wipe with a soft cloth soaked in lukewarm water or neutral detergent. Then wipe thoroughly with a soft dry cloth. Wipe the remote controller thoroughly with a soft dry cloth.
  • Page 27 CAUTION Please use earth line. Do not place the earth line near water or gas pipes, lightning-conductor, or the earth line of telephone. Improper installation of earth line may cause electric shock. A circuit breaker should be installed depending on the mounting site of the unit. Without a circuit breaker, the danger of electric shock exists.
  • Page 28 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”? Is the air filter blocked with dust? Does sunlight fall directly on the outdoor unit? Is the air flow of the outdoor unit obstructed?
  • Page 29 This product conforms with the protection requirements of council directives 89/336/EEC relating to electromagnetic compatibility and 73/23/EEC relating to electrical equipment designed for use within certain voltage limits. Please note: On switching on the equipment, particularly when the room light is dimmed, a slight brightness fluctuation may occur.

  • Page 30: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM 1019 Top air suction grille 1030 Front cover Vertical deflector Horizontal deflector Discharge grille About View from back (Pipe lead-out) 17.5 120.5 When piping is drawn horizontally, exchange the drain hose for the drain cap Drain Drain hose Drain outlet Drain cap...
  • Page 31 CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR 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) – 29 – 0305E Pg 28-32 4/1/06, 10:50 AM...

  • Page 32: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT (Room Temperature Thermistor) Thermostat Specifications MODEL RAS-70YH5 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 33 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-70YH5 COMPRESSOR MODEL JU1015D3 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 34 – 32 – 0305E Pg 28-32 4/1/06, 10:50 AM...

  • Page 35: Circuit Diagram

    CIRCUIT DIAGRAM Remote Control Key matrix table Output Input Operation selection Fan speed selection Automatic swing Door open Start/Stop Door shut Start/Stop Super silent cooling — — Hour up Hour down Door open On timer Door shut — Room temperature up Room temperature down Super cooling Door open...
  • Page 36 CIRCUIT DIAGRAM MODEL RAS-70YH5 – 35 – 0305E Pg 35 4/1/06, 10:52 AM...
  • Page 37 CIRCUIT DIAGRAM MODEL RAC-70YH5 – 37 – 0305E Pg 37 4/1/06, 10:53 AM...

  • Page 38: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAS-70YH5 MAIN P.W.B. Marking on P.W.B COMPONENT SIDE SOLDERING SIDE RECEIVING P.W.B. Marking on P.W.B – 39 – 0305E Pg 39-42 4/1/06, 10:53 AM...
  • Page 39 MODEL RAC-70YH5 MAIN P.W.B. – 40 – 0305E Pg 39-42 4/1/06, 10:53 AM...
  • Page 40 MAIN P.W.B. NF P.W.B. CAPA P.W.B. – 41 – 0305E Pg 39-42 4/1/06, 10:53 AM...
  • Page 41 – 42 – 0305E Pg 39-42 4/1/06, 10:53 AM...
  • Page 42 29. 66 – 43 – 0305E Pg 43 4/1/06, 10:54 AM...
  • Page 43 Table 1 Mode data file RAS-70YH5 LABEL NAME VALUE –1 WMAX 5800 min –1 WMAX2 5800 min WSTD 5000 min –1 WBEMAX 4000 min –1 CMAX 5800 min –1 CMAX2 5800 min –1 –1 CSTD 5300 min –1 CKYMAX 4000 min –1...
  • Page 44 ∆ 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 –1 2935 min 3.33 3100 min –1 3.66 3265 min –1 3435 min –1 4.33 3600 min –1 –1 4.66...
  • Page 45 Cooling Sleep Operation Final set temperature (Cooling/dehumidifying set temperature (+) sleep shift) (Cooling/dehumidifying set 0.5hr 1.5hr 2.5hr 3.5hr temperature = Remote control set temperature (+) SHIFTC) Set to 7 hours Sleep key Operation lamp Timer lamp Indoor fan See basic operation Lo (sleep) Outdoor fan Horizontal air...
  • Page 46 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 47 ∆ Table 3 TWMAX Basic Heating Operation Temperature Calculated difference compressor rpm 1.66 1965 min –1 2135 min –1 –1 2.33 2300 min 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 48 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”. 30 minutes after the sleep key is set, the sleep shift of set temperature starts. The maximum sleep shift of set temperature is 5°C, and the minimum is 12°C.

  • Page 49: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAS-70YH5 / RAC-70YH5 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT INDOOR UNIT S-TANK COND COMP HIGH PRESSURE REV-VALVE 5S-VALVE EXPANSION VALVE LOW PRESSURE STRAINER 2S-VALVE STRAINER HEATING OUTDOOR UNIT INDOOR UNIT S-TANK COND COMP HIGH PRESSURE REV-VALVE 5S-VALVE...
  • Page 50 – 58 – 0305E Pg 57-82 4/1/06, 10:59 AM...

  • Page 51: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION RAS-70YH5 1. Reset Circuit Micro computer Q202 Q201 C202 DC12V Line DC5V Line Base POWER ON POWER OFF Micro computer Pin 7 The reset circuit is used to reset the program to its initial settings when the power is turned on or when the power is recovered after a power failure.
  • Page 52 2. Buzzer Circuit Micro computer BUZZER When the buzzer is to be activated, buzzer output pin of the micro computer alternates between ON and OFF repeatedly at 4kHz and Q302 is turned ON/OFF accordingly. A 4kHz voltage is applied to the buzzer and the diaphragm of the buzzer vibrates to output 4kHz sound.
  • Page 53 5. Auto Sweep Motor Circuit CN12 Auto sweep motor for horizontal air deflectors Micro computer Rotor IC501 Fig. 5-1 Auto Sweep Motor Circuit (Horizontal air deflectors) Fig. 5-1 shows the Auto sweep motor drive circuit; the signals shown in Fig. 5-2 are output from pins –...
  • Page 54 6. Room Temperature Thermistor Circuit Fig. 6-1 shows the room temperature The voltage at A depends on the room thermistor circuit. temperature as shown in Fig. 6-2. Room Micro temperature computer thermistor R309 Room temp. input R310 C302 Fig. 6-1 Fig.
  • Page 55 8. Temporary Switch TEMPORARY SW Temporary switch R609 MICRO COMPUTER Fig. 8-1 The temporary switch is used to operate the air conditioner temporarily when the wireless remote control is lost or faulty. The air conditioner operates in the previous mode at the previously set temperature. However, when the power switch is set to OFF, it starts automatic operation.
  • Page 56 RAC-70YH5 1. Power Circuit REACTOR SPM2 DIODE TERMINAL STACK 1 BOARD COIL POWER RELAY 25A FUSE NF COIL1 (D25VB60) SURGE- TB10 ABSORBER R007 R008 TB11 ICP RELAY TB12 C009 L001 L002 DIODE STACK 2 (RC2) R002 C012 C014 C007 C015 C013 C008 Fig.
  • Page 57 (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 58 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 59 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 60 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 61 3. Power Module Circuit – 69 – 0305E Pg 57-82 4/1/06, 10:59 AM...
  • Page 62 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 63 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 64 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 65 (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 66 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 67 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 68 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 69 9. Reset Circuit Outdoor Q205 Microcomputer Q212 (AX-6S00) 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 70 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-70YHA, and their roles and temperature measuring points are shown as Table 10-1.
  • Page 71 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 72 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.
  • Page 73 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 74 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 75: 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 76 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 still working with the OPERATION and defrosts it as necessary before stopping operation.
  • Page 77 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 78: 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 79 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 80 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Timer lamp See Troubleshooting when the timer lamp Does the timer lamp on the indoor unit blink? blinks . Remove the terminal cover and check the voltage between terminal (C) and terminal (D) Terminal D Terminal C (0V)
  • Page 81 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Blinking of Timer lamp Reason for indication Possible cause Reversing valve defective (1) Reversing valve defective When the indoor heat exchanger (2) Heat exchanger thermistor dis- temperature is too low in the...
  • Page 82 SELF-DIAGNOSIS LIGHTING MODE MEASURING POSITION OF DC VOL TAGE (P1) "+ve" MEASURING POSITION OF MAIN P.W.B. DC VOL TAGE (N1) "+ve" SERVICE SWITCH LD301 SYSTEM POWER POWER P.W.B. MODULE (SPM2) LD302 LD303 SCREW (DANGER OF LD304 ELECTRIC SHOCK) – 90 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 83 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 84 2. Outdoor unit does not operate (but receives remote infrared signal) LD304 LD303 LD302 LD301 – 92 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 85 3. Only indoor fan does not operate (other is normal) the control P.W.B the control P.W.B 4. Air deflector does not move (others are normal) the control P.W.B 5. All systems stop from several seconds to several minutes after operation is started (all indicators are also off) –...
  • Page 86 6. Check the main P.W.B (power circuit) – 94 – 0305E Pg 90-109 4/1/06, 11:01 AM...

  • Page 87: Checking The Remote Controller

    CHECKING THE REMOTE CONTROLLER – 95 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 88 CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS – 96 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 89 – 97 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 90 – 98 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 91 – 99 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 92 – 100 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 93 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 94 (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 95 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 96: 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 Service switch more than 5 minutes.
  • Page 97 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 – 105 – 0305E Pg 90-109 4/1/06, 11:01 AM...

  • Page 98: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAS-70YH5 – 106 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 99 MODEL RAS-70YH5 PART N0. Q’TY / UNIT PARTS NAME RAS-70YH5 PMRAS-70YHA CABINET PMRAS-40CNH2 MOUNTING PLATE PMRAS-70YHA FAN MOTOR PMRAS-70YHA TANGENTIAL FAN PMRAS-25CNH2 P-BEARING ASSY PMRAS-51CHA1 FAN MOTOR BASE PMRAS-70YHA CYCLE ASSY PMRAS-51CHA1 FAN COVER PMRAS-18CP5 PIPE SUPPORT PMRAS-70YHA DRAIN PAN ASSY...

  • Page 100: Outdoor Unit

    PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL : RAC-70YH5 – 108 – 0305E Pg 90-109 4/1/06, 11:01 AM...
  • Page 101 MODEL RAC-70YH5 PART N0. Q’TY / UNIT PARTS NAME RAC-70YH5 PMRAC-80YHA COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-70YHA CONDENSER PMRAM-22NHZ4 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...
  • Page 102 HITACHI RAS-70YH5 / RAC-70YH5 PM NO. 0305E Printed in Malaysia 0305E cover 4/1/06, 12:03 PM...

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