Hitachi RAC-25NH4 Service Manual
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Hitachi RAC-25NH4 Service Manual

Hitachi RAC-25NH4 Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
SPECIFICATIONS
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
COOLING
CAPACITY
TOTAL INPUT
TOTAL AMPERES
HEATING
CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
JUNE 2004
RAI-ECPM
RAI-25NH4
RAI-40NH4
RAC-25NH4
RAC-50NH4
INDOOR UNIT
RAI-25NH4
1 PHASE, 50 Hz, 220-240V
(W)
695 (155~850)
(A)
(kW)
2.50 (0.90 ~ 3.00)
(B.T.U./h)
(W)
940 (155 ~ 1,050)
(A)
(kW)
3.50 (0.90 ~ 5.00)
(B.T.U./h)
W
580
H
285
D
580
(kg)
20
INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
PM
RAI-25NH4/RAC-25NH4
RAI-40NH4/RAC-50NH4
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 5
HOW TO USE ------------------------------------------------------------------------ 6
CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 29
MAIN PARTS COMPONENT --------------------------------------------------- 31
WIRING DIAGRAM ----------------------------------------------------------------- 33
CIRCUIT DIAGRAM ---------------------------------------------------------------- 35
PRINTED WIRING BOARD LOCATION DIAGRAM ---------------------- 41
BLOCK DIAGRAM ------------------------------------------------------------------ 43
BASIC MODE ------------------------------------------------------------------------ 45
REFRIGERATING CYCLE DIAGRAM ---------------------------------------- 59
AUTO SWING FUNCTION ------------------------------------------------------ 61
DESCRIPTION OF MAIN CIRCUIT OPERATION ------------------------ 62
TROUBLE SHOOTING ------------------------------------------------------------ 96
PARTS LIST AND DIAGRAM ------------------------------------------------- 116
DC INVERTER (CEILING CASSETTE TYPE)
OUTDOOR UNIT
RAC-25NH4
3.20-2.93
8,540
4.30-3.96
11,940
750
570
280
38
NO. 0212E
CONTENTS
INDOOR UNIT
OUTDOOR UNIT
RAI-40NH4
RAC-50NH4
1 PHASE, 50 Hz, 220-240V
1,380 (155~1,950)
6.35-5.81
4.00 (0.90 ~ 4.50)
13,660
1,620 (155 ~ 1,900)
7.45-6.82
5.20 (0.90 ~ 5.80)
17,750
580
850
285
650
580
298
20
60

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  • Page 1: Table Of Contents

    NO. 0212E RAI-25NH4/RAC-25NH4 RAI-40NH4/RAC-50NH4 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ------------------------------------------------------------------- 5 HOW TO USE ------------------------------------------------------------------------ 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 29 MAIN PARTS COMPONENT --------------------------------------------------- 31 WIRING DIAGRAM ----------------------------------------------------------------- 33...

  • Page 2: Safety During Repair Work

    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 RAI-25NH4 RAC-25NH4 RAC-50NH4 MODEL RAI-40NH4 FAN MOTOR 40 W FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR – JU1012D JU1013D COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) 3.0A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER...
  • Page 7 Figure showing the Installation of Indoor and Outdoor unit. The installation height of indoor unit must be 2.3m or more. CAUTION Be sure to completely seal any gap with putty. The indoor piping should be insulated with the enclosed insulation pipe. (If the insulator is insufficient, please use commersial products)

  • 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

    NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT AIR FILTER To prevent dust from coming into the indoor unit. (Refer page 19) INDOOR UNIT INDICATORS Light indicator showing the operating condition. (Refer page 5) SUCTION GRILL (AIR INLET) HORIZONTAL DEFLECTOR (AIR OUTLET) (Refer page 15) REMOTE CONTROL Send out operation signal to the indoor unit.
  • Page 11 OPERATION INDICATOR TEMPORARY SWITCH TEMPORARY SWITCH Temporary Switch Use this switch to start and stop when the remote controller does not work. [Use non-conductor stick (example toothpick)] Press By pressing the temporary switch, the operation is done in previously set operation mode.
  • Page 12 NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT REMOTE CONTROLLER Operate by pointing towards the signal receptor on the indoor unit. The range of control is about 7 meters. Signal receivable angle range is approximately 70°. However, if there is an electronic light sensor device (inverter) in the room, signal may not be received or receivable distance may become shorter.

  • Page 13: Various Functions

    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: How 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 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 ADJUSTING THE AIR DEFLECTOR Adjustment of the conditioned air in the upward and downward directions. According to “Dehumidifying” or “Cooling” operation, the horizontal air deflector is automatically set to the proper angle suitable for each operation. The deflector can be RESET swung up and down and also set to the desired angle using the “...
  • Page 22 HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER Remove the cover as shown in the figure and take out the Push and pull to the old batteries. direction of arrow Install the new batteries. The direction of the batteries should match the marks in the case.
  • Page 23 THE IDEAL WAYS OF OPERATION Suitable Room Temperature Install curtain or blinds Warning It is possible to Freezing temperature reduce heat is bad for health and a entering the waste of electric power. room through windows. Ventilation Effective Usage Of Timer At night, please use the “OFF or ON timer Caution operation mode”, together with your wake up...
  • Page 24 FOR USER’S INFORMATION The Air Conditioner And The Heat Source In The Room Caution If the amount of heat in the room is above the cooling capability of the air conditioner (for example: more people entering the room, using heating equipments and etc.), the preset room temperature cannot be achieved.

  • Page 25: Maintenance

    MAINTENANCE CAUTION Cleaning and maintenance must be carried out by qualified service personnel. Before the cleaning, stop operation and disconnect the power supply. Clean the filter at least once every one month. This helps save electricity cost. CLEANING OF AIR FILTER REMOVAL AND ATTACHMENT OF AIR FILTER PROCEDURE PUSH...

  • Page 26: Cleaning Of Front Panel

    2. CLEANING OF FRONT PANEL Wipe it with a soft dry cloth. When it is excessively dirty, wipe with soft cloth soaked in lukewarm water or neutral detergent. Then wipe thoroughly with a soft dry cloth. CAUTION Do not splash or direct water to the body of the unit when cleaning it as this may cause short circuit.

  • Page 27: After Sales Service And Warranty

    AFTER SALES SERVICE AND WARRANTY WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS. CONDITION CHECK THE FOLLOWING POINTS Is the fuse blown out or the circuit breaker tripped? Is the voltage normal? 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 28 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 29: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAI-25NH4, RAI-40NH4 650 (Panel) Unit : mm 600 (Opening on ceiling) 580 (Indoor unit) 400 (Suspension bolt) Wireless remote controller 97 (Drain) Narrow pipe fl6.35 Drain outlet Wide pipe fl12.7 Panel (Optional part RAI-ECPM) Ceiling Air outlet Air inlet Air outlet...
  • Page 30 CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR MODEL RAC-25NH4 MODEL RAC-50NH4 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) – 28 –...

  • Page 31: Main Parts Component

    20.7 (69.3) 28.3 (82.9) 31.0 (87.8) 29.0 (84.2) 36.0 (96.8) INDICATION 30.7 (87.3) 28.7 (83.7) 36.3 (97.9) FAN MOTOR Fan Motor Specifications RAI-25NH4 RAC-25NH4 MODEL RAI-40NH4 RAC-50NH4 POWER SOURCE DC: 0 ~ 35V DC360V OUTPUT 360V 0~35V CONNECTION 0~6V 0~15V...
  • Page 32 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-25NH4 RAC-40NH4 COMPRESSOR MODEL JU1012D JU1013D PHASE SINGLE RATED VOLTAGE AC 220 ~ 240 V RATED FREQUENCY 50 Hz POLE NUMBER WHITE CONNECTION YELLOW 20°C 2M = 1.05 (68°F) RESISTANCE VALUE 75°C 2M = 1.28 (167°F)

  • Page 33: Wiring Diagram

    WIRING DIAGRAM MODEL RAI-25NH4 / RAC-25NH4 RAI-40NH4 / RAC-40NH4 INDOOR UNIT OUTDOOR UNIT – 31 –...

  • Page 34: 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 SEG18 SEG1...
  • Page 35 CIRCUIT DIAGRAM MODEL RAI-25NH4, RAI-40NH4 – 35 –...
  • Page 36 CIRCUIT DIAGRAM MODEL RAC-25NH4 RAC-50NH4 – 37 –...

  • Page 37: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAI-25NH4, RAI-40NH4 MAIN P.W.B. Marking on P.W.B. COMPONENT SIDE SOLDERING SIDE – 39 –...
  • Page 38 MODEL RAC-25NH4, RAC-50NH4 MAIN P.W.B. Marking on P.W.B – 40 –...
  • Page 39 RAI-25NH4 / RAC-25NH4 RAI-40NH4 / RAC-50NH4 SPM2 Outdoor unit Terminal board Trip signal synthesis circuit Wireless receive LCD wireless circuit Filter. Room temperature Operation. thermistor Timer. Drain Pump Motor Auto sweep motor for Heat exchanger Air deflector thermistor Electric Expansion...
  • Page 40 – 43 –...
  • Page 41 Table 1 Mode data file RAI-25NH4 RAI-40NH4 LABEL NAME VALUE –1 –1 WMAX 4400 min 6000 min –1 –1 WMAX2 4500 min 6000 min –1 –1 WSTD 3300 min 4250 min –1 –1 WBEMAX 2800 min 3500 min –1 –1 CMAX 2900 min 4700 min...
  • Page 42 ∆ 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 43 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 44 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 45 ∆ Table 3 TWMAX Basic Heating Operation Temperature Calculated difference compressor rpm –1 1.66 1965 min –1 2135 min 2.33 2300 min –1 Heating set temperature 2.66 2465 min –1 (remote control set temperature (+)) –1 2635 min 3.33 2800 min –1 Dash period 18˚C...
  • Page 46 TDF TDF TDF 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.

  • Page 47: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAI-25NH4 RAC-25NH4 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT INDOOR UNIT SERVICE VALVE (3/8) SINGLE-ENDED UNION (3/8) SUCTION TANK REVERSING VALVE ELECTRIC EXPANSION VALVE SERVICE VALVE (1/4) SINGLE-ENDED UNION (1/4) STRAINER STRAINER CHARGING PIPE HEATING OUTDOOR UNIT INDOOR UNIT...
  • Page 48 REFRIGERATING CYCLE DIAGRAM MODEL RAI-40NH4 RAC-50NH4 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT SERVICE VALVE INDOOR UNIT (1/2) SINGLE-ENDED ADAPTOR UNION (3/8) SUCTION TANK REVERSING VALVE ELECTRIC EXPANSION VALVE SERVICE VALVE (1/4) STRAINER SINGLE-ENDED UNION (1/4) STRAINER HEATING SERVICE VALVE OUTDOOR UNIT INDOOR UNIT (1/2) SINGLE-ENDED...
  • Page 49 – 59 –...

  • Page 50: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAI-25NH4, RAI-40NH4 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 51 2. Receiver Circuit R412 R411 R413 R611 13 RECEIVER I/P Microcomputer Fig. 2-1 The light receiver unit receives the infrared signal from the wireless remote control. The receiver amplifies and shapes the signal and outputs it. 3. Buzzer Circuit R722 Microcomputer Buzzer output Q722...
  • Page 52 4. Auto Sweep Motor Circuit D712 Auto sweep motor for horizontal air deflector Rotor R711 AUTO SWEEP Q711 MOTOR Q712 R712 C712 Microcomputer IC711 AUTO SWEEP MOTOR AUTO SWEEP MOTOR P.W.B. MAIN Fig.4-1 Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig.4-2 are output from pins –...
  • Page 53 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 54 7. 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 55 Model RAI-25NH4, RAI-40NH4 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 C014 C012 C007 C015 C013...
  • Page 56 (3) Smoothing capacitor (C501, C502, C503) This smoothes (averages) the voltage rectified by the diode stacks. <Notes> Smoothing capacitor C501 is not available for model RAC-25NH4 and RAC-35NH4. Smoothing Capacitors SPM2 Fig. 1-2 Be careful to avoid an electric shock as a high voltage is generated.
  • Page 57 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 58 Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other. R805 R813 R803 IC801 L801 R812 R810 IF transmit Q803 Q802 output (SDO) R804 R806 R811 C803 C802 C801 C804 MICROCOMPUTER Q801 R824 R826 R822...
  • Page 59 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 60 – 70 –...
  • Page 61 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 62 3. Power Module Circuit – 72 –...
  • Page 63 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 64 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 intermittent waveform as shown in Fig.
  • Page 65 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 R917 D909 R002...
  • Page 66 (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 reaches the specified value, REG2 turns on and current flows to PQ2 1-2.
  • Page 67 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 microcomputer depending on the operation condition shows in Table 5-1.
  • Page 68 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 69 7. Drive Circuit Fig. 7-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration. – 79 –...
  • Page 70 [Low speed rotation mode] Fig. 7-2 [High speed rotation mode] Fig. 7-3 – 80 –...
  • Page 71 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 CN13...
  • Page 72 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 73 (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 74 Detection Resistor Direct Current DC 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 75 It is required to maintain the start current (DC current) constant to smooth the start of the DC motor for the compressor. RAC-25NH4, RAC-35NH4, RAC-50NH4 uses software to control the start current. The start current varies when the supply voltage varies. This control method copes with variations in the voltages as follows.
  • Page 76 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 77 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. Fig.
  • Page 78 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 79 < Reference > When operation stop with LD301 blinks 12 times, it may be caused by faulty DC fan motor. In this case, please check CN6 and CN12 connection first. It makes Fan Motor Lock also if those connectors are in misconnection. DC Fan Motor has broken when 2A Fuse was burned.
  • Page 80 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 81: Service Call Q & A

    SERVICE CALL Q & A Model RAI-25NH4 RAI-40NH4 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 82: Auto Operation

    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 83 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 84: Trouble Shooting

    TROUBLE SHOOTING Model RAI-25NH4 RAI-40NH4 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 85 Do this with smoothing capacitors kept connected. By removing red/ gray lead wire from diode stack, power supply can be shut off. (corresponding to + and – System power module terminals of system power module) RAC-25NH4 SPM2 Smoothing capacitors RAC-50NH4 Smoothing capacitors SPM2...
  • Page 86 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Model RAI-25NH4 RAI-40NH4 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 87 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Model RAI-25NH4, RAI-40NH4 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAI-25NH4, RAI-40NH4 Timer indicator flashing mode Reason for display Section of estimated fault Four-way valve faulty (1) Four-way valve faulty.
  • Page 88 SELF-DIAGNOSIS LIGHTING MODE MODEL: RAI-25NH4, RAI-40NH44 – 98 –...
  • Page 89 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 90 2. Outdoor unit does not operate (but receives remote infrared signal) – 100 –...
  • Page 91 3. Only indoor fan does not operate (other is normal) Is approx 20 V DC generated Is 5 V DC generated between pins between pins (blue) and (red) Replace indoor fan motor. (blue) and (yellow) of CN10? of CN 10 when operated at high fan speed during cooling? Check disconnection, etc of lead wires.
  • Page 92 6. All systems stop from several seconds to several minutes after operation is started (all indicators are also off) Set to the "Hi" fan mode. The operation lamp lights once and goes out in 5-10 seconds. Disconnect, CN10 and set to the fan mode again. Check to see if shorting, etc.

  • Page 93: Checking The Remote Controller

    CHECKING THE REMOTE CONTROLLER – 103 –...
  • Page 94 CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAI-25NH4, RAI-40NH4 – 104 –...
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  • Page 99: Power Circuit

    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 100 (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 101 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 102: How To Operate The Outdoor Unit Independently

    5 minutes. Service switch (forced-cooling mode is set by Electrical Box Cover pressing for 1 second or more, and stopped by pressing again.) RAC-25NH4 Electrical Box Cover Self diagnosis lamps (LD303, 302, 301) RAC-50NH4 (Cautions) (1) If interface signal (DC 35V) terminals C and D are not connected when the outdoor unit is in forced cool mode, the outdoor unit defect indicator (LD301) will blink 9 times during operation to indicate communication error.
  • Page 103 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 – 113 –...

  • Page 104: Parts List And Diagram

    PARTS LIST AND DIAGRAM MODEL RAI-ECPM – 114 –...
  • Page 105 MODEL RAI-ECPM PART N0. Q’TY / UNIT PARTS NAME RAI-ECPM PMRAI-ECPM HORIZONTAL AIR DEFLECTOR 1 PMRAI-ECPM HORIZONTAL AIR DEFLECTOR 2 PMRAI-ECPM STEP MOTOR PMRAI-ECPL FILTER PMRAI-ECPM SUCTION GRILL PMRAI-ECPM P.W.B. (DISPLAY) – 115 –...
  • Page 106 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAI-25NH4, RAI-40NH4 – 116 –...
  • Page 107 MODEL RAI-25NH4 PART N0. Q’TY / UNIT PARTS NAME RAI-25NH4 PMRAI-32CNH2 25W MOTOR RAMD-350BW FLOAT SWITCH PMRAI-32CNH2 THERMISTOR (HEAT EXCHANGER) PMRAI-32CNH2 THERMISTOR (ROOM TEMPERATURE) PMRAI-32CNH2 TURBO FAN PMRAI-32CNH2 DRAIN PAN ASSEMBLY PMRAS-51CHA1 REMOTE CONTROL ASSEMBLY PMRAS-10C3M REMOTE CONTROL SUPPORT PMRAI-32CNH2 COVER PIPE (INSULATOR) (2000L) PMRAI-32CNH2 HEAT INSULATOR PIPE (180L)
  • Page 108 MODEL RAI-40NH4 PART N0. Q’TY / UNIT PARTS NAME RAI-40NH4 PMRAI-32CNH2 25W MOTOR RAMD-350BW FLOAT SWITCH PMRAI-32CNH2 THERMISTOR (HEAT EXCHANGER) PMRAI-32CNH2 THERMISTOR (ROOM TEMPERATURE) PMRAI-32CNH2 TURBO FAN PMRAI-32CNH2 DRAIN PAN ASSEMBLY PMRAS-51CHA1 REMOTE CONTROL ASSEMBLY PMRAS-10C3M REMOTE CONTROL SUPPORT PMRAI-32CNH2 COVER PIPE (INSULATOR) (2000L) PMRAI-32CNH2 HEAT INSULATOR PIPE (180L)
  • Page 109 OUTDOOR UNIT MODEL : RAC-25NH4, RAC-50NH4 – 119 –...
  • Page 110 MODEL RAC-25NH4 PART N0. Q’TY / UNIT PARTS NAME RAC-25NH4 PMRAC-25NH4 BASE PMRAC-25NH4 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-25NH4 CONDENSER PMRAC-25NH4 REVERSING VALVE PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAC-25NH4 VALVE (2S) PMRAC-25NH4 VALVE (4S) PMRAC-40CNH2 THERMISTOR (OH) PMRAC-25NH4 OVERHEAT THERMISTOR SUPPORT...
  • Page 111 MODEL RAC-50NH4 PART N0. Q’TY / UNIT PARTS NAME RAC-50NH4 PMRAC-50NH4 BASE PMRAC-50NH4 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-25NH4 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 RAI-25NH4 PM NO. 0212E RAI-40NH4 Printed in Malaysia...

This manual is also suitable for:

Rai-25nh4Rai-40nh4Rac-50nh4

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