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Hitachi RAD-25NH4 Service Manual

Room air conditioner
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See also: Installation Manual

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
RAD-25NH4
RAD-40NH4
RAC-25NH4
RAC-50NH4
INDOOR UNIT
RAD-25NH4
1 PHASE, 50 Hz, 220-240V
(W)
(A)
(kW)
2.50 (1.00 ~ 3.00)
(B.T.U./h)
(W)
1,000 (210 ~ 1,280)
(A)
(kW)
3.80 (1.10 ~ 4.80)
(B.T.U./h)
W
750
H
235
D
400
(kg)
19
INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
PM
RAD-25NH4/RAC-25NH4
RAD-40NH4/RAC-50NH4
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 4
HOW TO USE ------------------------------------------------------------------------ 6
CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 25
MAIN PARTS COMPONENT --------------------------------------------------- 27
WIRING DIAGRAM ----------------------------------------------------------------- 29
CIRCUIT DIAGRAM ---------------------------------------------------------------- 31
PRINTED WIRING BOARD LOCATION DIAGRAM ---------------------- 37
BLOCK DIAGRAM ------------------------------------------------------------------ 39
BASIC MODE ------------------------------------------------------------------------ 41
REFRIGERATING CYCLE DIAGRAM ---------------------------------------- 55
AUTO SWING FUNCTION ------------------------------------------------------- 57
DESCRIPTION OF MAIN CIRCUIT OPERATION ------------------------ 58
TROUBLE SHOOTING ------------------------------------------------------------ 92
PARTS LIST AND DIAGRAM ------------------------------------------------- 112
DC INVERTER (CEILING CASSETTE TYPE)
OUTDOOR UNIT
RAC-25NH4
720 (220~980)
3.31-3.03
8,540
4.59-4.21
12,980
750
570
280
38
NO. 0214E
CONTENTS
INDOOR UNIT
OUTDOOR UNIT
RAD-40NH4
RAC-50NH4
1 PHASE, 50 Hz, 220-240V
1,400 (220~1,560)
6.43-5.89
4.00 (1.00 ~ 4.50)
13,660
1,770 (210 ~ 1,920)
8.13-7.45
5.20 (1.10 ~ 5.80)
17,750
750
850
235
650
400
298
19
60

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Summary of Contents for Hitachi RAD-25NH4

  • Page 1: Table Of Contents

    NO. 0214E RAD-25NH4/RAC-25NH4 RAD-40NH4/RAC-50NH4 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ------------------------------------------------------------------- 4 HOW TO USE ------------------------------------------------------------------------ 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 25 MAIN PARTS COMPONENT --------------------------------------------------- 27 WIRING DIAGRAM ----------------------------------------------------------------- 29...
  • Page 2 SAFETY DURING REPAIR WORK 1. In order to disassemble and repair the unit in question, be sure to disconnect the power cord plug from the power outlet before starting the work. 2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and the replacement must be effected in correct manner according to the instructions in the Service Manual of the unit.
  • Page 3 WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS 1. Scope The standards provide for items to be generally observed in carrying and handling semiconductors in relative manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal goods such as rejected goods being returned).
  • Page 4 (6) Use a three wire type soldering iron including a grounding wire. Metal plate (of aluminium, stainless steel, etc.) Working table Resistor of 1 M (1/2W) Staple Earth wire Bare copper wire (for body earth) Fig. 3. Grounding of the working table Soldering iron Grounding wire...
  • Page 5 CAUTION In quiet operation or stopping the running, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally, but this noise is not abnormal for the operation. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 6: Specifications

    SPECIFICATIONS RAD-25NH4 RAC-25NH4 RAC-50NH4 MODEL RAD-40NH4 40 W FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR – JU1012D JU1013D COMPRESSOR COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) 3.0A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER...
  • Page 7 [Indoor unit installation] CAUTION Always install the indoor unit level. Units not installed level may leak. Be sure to com- pletely seal any gap with putty. Adiabated pipes must always be Use the holder used for both when the pipe large and small is drawn from Drain pipe...
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  • Page 10 FULL DUCT SEMI DUCT NON DUCT – 8 –...
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  • Page 12 an speed f – 10 –...
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  • Page 14 displa – 12 –...
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  • Page 18 (ON) mark b (ON) mar – 16 –...
  • Page 19 The time indication star lighting instead of flashing. The setting of the current time (OFF) mar sign lights A beep occurs and the (TIMER) lamp lights on the indoor unit. (ON) mar (RESER A beep occurs and the (TIMER) lamp lights on the indoor unit. –...
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  • Page 27: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAD-25NH4, RAD-40NH4 Unit: mm Indication panel Wireless remote controller Electric box ( Possible to move , Right side ) Hanger ( Use for hanging unit ) Drain hose Narrow pipe ( Wide pipe ( Cautions: 1.
  • Page 28 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) – 26 –...

  • Page 29: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAD-25NH4/RAD-40NH4 THERMOSTAT MODEL OPERATION MODE COOL HEAT 14.9 (59.3) 20.4 (68.8) INDICATION 14.3 (58.3) 21.0 (69.1) TEMPERATURE 22.9 (73.7) 28.4 (83.1) INDICATION °C (°F) 22.3 (72.7) 29.0 (84.1) 30.9 (88.1) 36.4 (97.7) INDICATION 30.3 (87.1)
  • Page 30 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) WHITE YELLOW...

  • Page 31: Wiring Diagram

    WIRING DIAGRAM MODEL RAD-25NH4 / RAC-25NH4 RAD-40NH4 / RAC-40NH4 BLU : BLUE : YELLOW BRN : BROWN WHT : WHITE GRY : GRAY ORN : ORANGE GRN : GREEN : RED : BLACK PNK : PINK : VIOLET INDOOR UNIT...

  • Page 32: 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 33 CIRCUIT DIAGRAM MODEL RAD-25NH4 RAD-40NH4 – 33 –...
  • Page 34 CIRCUIT DIAGRAM MODEL RAC-25NH4 RAC-50NH4 – 35 –...

  • Page 35: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAD-25NH4, RAD-40NH4 MAIN P.W.B. Marking on P.W.B. COMPONENT SIDE SOLDERING SIDE – 37 –...
  • Page 36 MODEL RAC-25NH4, RAC-50NH4 MAIN P.W.B. Marking on P.W.B – 38 –...
  • Page 37 RAD-25NH4 / RAC-25NH4 RAD-40NH4 / RAC-50NH4 SPM2 Outdoor unit Terminal board Trip signal synthesis circuit Wireless receive LCD wireless circuit Room temperature Operation. thermistor Timer. Drain Pump Motor Auto sweep motor for Heat exchanger Air deflector thermistor Electric Expansion valve...
  • Page 38 RAD-25NH4, RAD-40NH4 – 41 –...
  • Page 39 Table 1 Mode data file RAD-25NH4 RAD-40NH4 LABEL NAME VALUE –1 –1 WMAX 4400 min 5400 min –1 –1 WMAX2 4500 min 5400 min –1 –1 WSTD 3500 min 4700 min –1 –1 WBEMAX 2800 min 3500 min –1 –1...
  • Page 40 ∆ Table 2 TCMAX Temperature Calculated difference compressor rpm 1.66 2265 min –1 –1 2435 min 2.33 2600 min –1 2.66 2765 min –1 2935 min –1 –1 3.33 3100 min 3.66 3265 min –1 3435 min –1 –1 4.33 3600 min 4.66 3765 min...
  • Page 41 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 42 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 43 ∆ 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 44 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 45: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAD-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 46 REFRIGERATING CYCLE DIAGRAM MODEL RAD-40NH4 RAC-50NH4 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT SERVICE VALVE INDOOR UNIT (1/2) SINGLE-ENDED ADAPTOR UNION (3/8) 12.7 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...
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  • Page 48: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAD-25NH4, RAD-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 49 2. Receiver Circuit R419 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 Fig.
  • Page 50 4. Auto Sweep Motor Circuit Microcomputer IC711 AUTO SWEEP MOTOR FOR HORIZONTAL AIR DEFLECTOR 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 – of microcomputer. Horizontal air Microcomputer pins Step width deflectors: 10ms.
  • Page 51 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 52 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 53 Model RAC-25NH4, RAC-50NH4 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 54 (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 55 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 56 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 57 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 58 – 68 –...
  • Page 59 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 60 3. Power Module Circuit – 70 –...
  • Page 61 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 62 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 63 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 64 (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 65 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 66 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 67 7. Drive Circuit Fig. 7-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration. – 77 –...
  • Page 68 [Low speed rotation mode] Fig. 7-2 [High speed rotation mode] Fig. 7-3 – 78 –...
  • Page 69 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 70 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 71 (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 72 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 73 R500, R253, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage (260- 380V) via HIC and applies correction to the overload set value so the DC current is low (high) when the DC voltage is high (low). (Since the load level is indicated by the DC voltage multiplied by DC current, R247, R248, R249 are provided to perform the same overload judgement even when the voltage varies.) Amplification : low...
  • Page 74 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 75 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 76 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 77 < 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 78 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 79: Service Call Q & A

    SERVICE CALL Q & A Model RAD-25NH4 RAD-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 80 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 81 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 82: Trouble Shooting

    TROUBLE SHOOTING Model RAC-25NH4 RAC-50NH4 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 83 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 84 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Model RAC-25NH4 RAC-50NH4 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 85 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Model RAD-25NH4, RAD-40NH4 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAD-25NH4, RAD-40NH4 Timer indicator flashing mode Reason for display Section of estimated fault Four-way valve faulty (1) Four-way valve faulty.
  • Page 86 SELF-DIAGNOSIS LIGHTING MODE MODEL: RAC-25NH4, RAC-50NH4 – 96 –...
  • Page 87 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 88 2. Outdoor unit does not operate (but receives remote infrared signal) – 98 –...
  • Page 89 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 90 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 91 CHECKING THE REMOTE CONTROLLER – 101 –...
  • Page 92 CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAC-25NH4, RAC-50NH4 – 102 –...
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  • Page 97 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 98 (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 99 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 100: How To Operate The Outdoor Unit Independently

    HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT MODEL RAC-25NH4, RAC-50NH4 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 101 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 – 111 –...

  • Page 102: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAD-25NH4, RAD-40NH4 – 112 –...
  • Page 103 MODEL RAD-25NH4 PART N0. Q’TY / UNIT PARTS NAME RAD-25NH4 RAD-28MX DRAIN PAN RAMD-350BW FAN MOTOR SUPPORT RUBBER RAMD-350BW SPECIAL SCREW RAMD-28GX PUMP ASSEMBLY RAMD-350BW DRAIN HOSE RAMD-350BW PUMP HOSE RAMD-350BW FLOAT SWITCH RAD-28MX EVAPORATOR ASSEMBLY RAD-28MX PIPE SET RAD-25QH4...
  • Page 104 PART N0. Q’TY / UNIT PARTS NAME RAD-25NH4 RAS-2810KX CURRENT PROTECTOR (2.0A) RAD-25NH4 LED COVER RAD-28MX DRAIN PIPE RAS5645TWU DRAIN CAP RAS-287AX UNION (2) RAS-287AX UNION (3) – 114 –...
  • Page 105 THERMISTOR (HEAT) RAD-28MX THERMISTOR (TEMPERATURE) RAD-40NH4 P.W.B. (MAIN) RAC4010KX2 FERITE CORE (935) RAC-228JX SLIDE SWITCH ATI-0972B TERMINAL BOARD (2P) RAD-25NH4 P.W.B. (INDICATION) RAD-25QH4 REMOTE CONTROL ASSEMBLY RAMJ-250BW INSULATOR PIPE RAS-258JX REMOCON SUPPORT RAD-28MX INSULATOR PIPE (236L) RAD-28QH1 UPPER PLATE (2)
  • Page 106 PART N0. Q’TY / UNIT PARTS NAME RAD-40NH4 RAS-2810KX CURRENT PROTECTOR (2.0A) RAD-25NH4 LED COVER RAD-28MX DRAIN PIPE RAS5645TWU DRAIN CAP RAS-287AX UNION (2) RAS-287AX UNION (3) – 116 –...
  • Page 107 OUTDOOR UNIT MODEL : RAC-25NH4, RAC-50NH4 – 117 –...
  • Page 108 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 PMRAC-25NH4 OVERLOAD RELAY COVER PMRAC-40CNH2...
  • Page 109 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 110 HITACHI RAD-25NH4/RAC-25NH4 PM NO. 0214E RAD-40NH4/RAC-50NH4 Printed in Malaysia...

This manual is also suitable for:

Rac-25nh4Rad-40nh4Rac-50nh4

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