Hitachi RAI-50NH5 Service Manual

[Page 1] Hitachi RAI-50NH5

NO. 0274E SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ROOM AIR CONDITIONER INDOOR UNIT + OUTDOOR UNIT DECEMBER 2005 Refrigeration & Air-Conditioning Division SERVICE MANUAL PM REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATI...

[Page 2] Hitachi RAI-50NH5

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 r...

[Page 3] Hitachi RAI-50NH5

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 s...

[Page 4] Hitachi RAI-50NH5

(6) Use a three wire type soldering iron including a grounding wire. Bare copper wire (for body earth) Working table Resistor of 1 M (1/2W) Earth wire Fig. 3. Grounding of the working table 2 Screw stop at the screwed part using a rag plate Solderin...

[Page 5] Hitachi RAI-50NH5

1. 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. 2. When it thunders near by, it is recommend to stop the operation ...

[Page 6] Hitachi RAI-50NH5

SPECIFICATIONS MODEL FAN MOTOR FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR...

[Page 7] Hitachi RAI-50NH5

The installation height of indoor unit must be 2.3m or more. ! CAUTION Figure showing the Installation of Indoor and Outdoor unit. ( ) above 200mm above 700mm above 50mm when installed on the ceiling of balcony above 100mm Maximum pipe length 20m Min...

[Page 8] Hitachi RAI-50NH5

– 6 – ! 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” sect...

[Page 9] Hitachi RAI-50NH5

– 7 – PRECAUTIONS DURING OPERATION ● 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. ● Do not...

[Page 10] Hitachi RAI-50NH5

– 8 – INDOOR UNIT NAMES AND FUNCTIONS OF EACH PART WIDTH (mm) 580 MODEL RAI-50NH5 HEIGHT (mm) 285 DEPTH (mm) 580 MODEL NAME AND DIMENSIONS AIR FILTER To prevent dust from coming into the indoor unit. (Refer page 19) INDOOR UNIT INDICATORS Light i...

[Page 11] Hitachi RAI-50NH5

– 9 – INDOOR UNIT INDICATORS TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work. [Use non-conductor stick (example toothpick)] ● By pressing the temporary switch, the operation is done in previously set ...

[Page 12] Hitachi RAI-50NH5

– 10 – AUTO HEAT DEHUMIDIFY COOL FAN FAN SPEED LOW MED HI SLEEPING STOP (CANCEL) START (RESERVE) START/STOP TIME TIMER SET TIMER SELECTOR ON TIMER OFF TIMER AUTO SWING ˚ CH RESET ˚ CH NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT ● Signal ...

[Page 13] Hitachi RAI-50NH5

– 11 – AUTOMATIC OPERATION The device will automatically determine the mode of operation, HEAT, COOL or DEHUMIDIFY depending on the current room temperature. The selected mode of operation will change when the room temperature varies. However the...

[Page 14] Hitachi RAI-50NH5

– 12 – 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 devic...

[Page 15] Hitachi RAI-50NH5

– 13 – 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. ■ Dehumidifying Function When the room temperature is higher than the tem...

[Page 16] Hitachi RAI-50NH5

– 14 – ˚ C RESET ˚ C 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 t...

[Page 17] Hitachi RAI-50NH5

– 15 – FAN SPEED (AUTO) ..... When the AUTO fan speed mode is set in the cooling/heating operation: For the heating operation ● The fan speed will automatically change according to the temperature of discharged air. ● When the difference of ...

[Page 18] Hitachi RAI-50NH5

– 16 – HOW TO SET THE TIMER ON/OFF-Timer ● The device will turn on (off) and off (on) at the designated times. ● The switching occurs first at the preset time that comes earlier. ● The arrow mark appearing on the display indicates the seque...

[Page 19] Hitachi RAI-50NH5

– 17 – 3 Point the signal window of the remote controller toward the indoor unit, and press the (RESERVE) button. The (OFF) mark starts lighting instead of flashing and the sign (RESERVED) lights. A beep occurs and the (TIMER) la...

[Page 20] Hitachi RAI-50NH5

– 18 – HOW TO SET THE SLEEP TIMER 1 Set the ON-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 Sleep timer Ind...

[Page 21] Hitachi RAI-50NH5

– 19 – ENGLISH ADJUSTING THE AIR DEFLECTOR RESET 1 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 prop...

[Page 22] Hitachi RAI-50NH5

– 20 – HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER 1 Remove the cover as shown in the figure and take out the old batteries. = 2 Install the new batteries. The direction of the batteries should match the marks in the case. 1. Do not us...

[Page 23] Hitachi RAI-50NH5

– 21 – ENGLISH Suitable Room Temperature Install curtain or blinds Ventilation Effective Usage Of Timer Do Not Forget To Clean The Air Filter Please Adjust Suitable Temperature For Baby And Children Warning Freezing temperature is bad for hea...

[Page 24] Hitachi RAI-50NH5

– 22 – FOR USER’S INFORMATION The Air Conditioner And The Heat Source In The Room Not Operating For A Long Time When Lightning Occurs Caution If the amount of heat in the room is above the cooling capability of the air conditioner (for exam...

[Page 25] Hitachi RAI-50NH5

– 23 – ENGLISH MAINTENANCE 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 electrici...

[Page 26] Hitachi RAI-50NH5

– 24 – 1 2 3 REGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS EITHER EVERY HALF YEARLY OR YEARLY. CONTACT YOUR SALES AGENT SHOULD YOU NEED ANY HELP. Is the earth line disconnected or broken? WARNING Coming off or breakage of grounding wire ...

[Page 27] Hitachi RAI-50NH5

– 25 – ENGLISH AFTER SALES SERVICE AND WARRANTY WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS. When it does not operate ● Is the fuse blown out or the circuit breaker tripped? ● Is the voltage normal? ● Is the circuit breaker “ON”...

[Page 28] Hitachi RAI-50NH5

– 26 – MEMO ..................................................................................................................................................................................... .......................................................

[Page 29] Hitachi RAI-50NH5

– 27 – CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAI-50NH5 Note: 1. Insulated pipes should be used for both the narrow and wide dia. pipes. 2. Piping length is within 20m. 3. Height difference of the piping between the indoor unit and the outdoo...

[Page 30] Hitachi RAI-50NH5

– 28 – CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR MODEL RAC-50NH5 Handle Air suction grille 10464 26 850 955 79 650 96 169.5 638 1010 10 320 340 Air outlet 340 2022 298 201 Handle Holes for anchor bolt (2-ø12) Fixing hole 507 198 57 12 37 ...

[Page 31] Hitachi RAI-50NH5

– 29 – MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications FAN MOTOR Fan Motor Specifications CONNECTION TEMPERATURE °C (°F) INDICATION 16 INDICATION 24 INDICATION 32 THERMOSTAT MODEL IC OPERATION MODE COOL HEAT MODEL RAI-50N...

[Page 32] Hitachi RAI-50NH5

– 30 – WHITE RED YELLOW MODEL COMPRESSOR MODEL PHASE SINGLE RATED VOLTAGE AC 220 ~ 240 V RATED FREQUENCY 50 Hz POLE NUMBER 4 COMPRESSOR MOTOR Compressor Motor Specifications CONNECTION 20°C (68°F) 75°C (167°F) ( ) RESISTANCE VALUE ! CAUTION W...

[Page 33] Hitachi RAI-50NH5

MODEL RAI-50NH5 / RAC-50NH5 WIRING DIAGRAM – 31 – INDOOR UNIT OUTDOOR UNIT 0274E Pg 31(RAI-50NH5) 19/10/05, 2:59 PM1 ...

[Page 34] Hitachi RAI-50NH5

Remote Control CIRCUIT DIAGRAM – 33 – 1 2 3 4 5 6 7 8 10 11 13 14 15 16 17 19 20 9 12 18 SEG19 SEG18 SEG17 SEG16 SEG21 SEG24 SEG25 SEG26 SEG27 SEG28 NC NC NC NC NC NC NC NC NC SEG20 SEG5 SEG0 SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 COM3 COM2 COM1 COM0...

[Page 35] Hitachi RAI-50NH5

CIRCUIT DIAGRAM MODEL RAI-50NH5 – 35 – 0274E Pg 35(RAI-50NH5) 19/10/05, 3:09 PM1 ...

[Page 36] Hitachi RAI-50NH5

CIRCUIT DIAGRAM MODEL RAC-50NH5 – 37 – 0274E Pg 37(RAI-50NH5) 19/10/05, 3:14 PM1 ...

[Page 37] Hitachi RAI-50NH5

– 39 – PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAI-50NH5 MAIN P.W.B. Marking on P.W.B. COMPONENT SIDE SOLDERING SIDE 0274E Pg 39-40(RAI-50NH5) 19/10/05, 3:16 PM39 ...

[Page 38] Hitachi RAI-50NH5

– 40 – MODEL RAC-50NH5 MAIN P.W.B. Marking on P.W.B COMPONENT SIDE 0274E Pg 39-40(RAI-50NH5) 19/10/05, 3:16 PM40 ...

[Page 39] Hitachi RAI-50NH5

– 41 – Wireless receive circuit Filter. Operation. Timer. Auto sweep motor for Air deflector Drain Pump Motor LCD wireless Heat exchanger thermistor Room temperature thermistor Reset circuit Initial setting circuit Temporary switch Electric Expan...

[Page 40] Hitachi RAI-50NH5

– 43 – 47. 0274E Pg 43(RAI-50NH5) 19/10/05, 3:24 PM1 ...

[Page 41] Hitachi RAI-50NH5

– 45 – Table 1 Mode data file RAI-50NH5 LABEL NAME VALUE WMAX 6000 min –1 WMAX2 6000 min –1 WSTD 4250 min –1 WBEMAX 3500 min –1 CMAX 4700 min –1 CMAX2 4700 min –1 CSTD 4100 min –1 CKYMAX 3500 min –1 CJKMAX 2700 min –1 CBEMAX 200...

[Page 42] Hitachi RAI-50NH5

– 47 – Reversing valve (heating “on” mode) NOTE (9) Notes: (1) Condition for entering into Cool Dashed mode. When fan set to “Hi” or “Auto mode” and temperature difference between indoor temperature and set temperature has a correspo...

[Page 43] Hitachi RAI-50NH5

– 49 – Notes: (1) The sleep operation starts when the sleep key is pressed. (2) When the sleep key is set, the maximum compressor speed is limited, and the indoor fan is set to “sleep Lo”. (3) 30 minutes after the sleep key is set, the sleep ...

[Page 44] Hitachi RAI-50NH5

+ + Delay –1.33˚C –0.66˚C – 51 – 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 temperat...

[Page 45] Hitachi RAI-50NH5

– 53 – 1.33˚C. SFTDSW 0.66˚C. Fan speed set to "auto" 1 min. Hi Lo Hi Hi Hi ultra Hi Basic Heating Operation Start Stop Start Start StopStop Thermo OFF Thermo OFF Heating set temperature (remote control set temperature (+)) Start/sto...

[Page 46] Hitachi RAI-50NH5

– 55 – 1 min WMIN TDF TDF TDF TDF TDF TDF Notes: (1) The sleep operation starts when the sleep key is pressed. (2) 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”. (...

[Page 47] Hitachi RAI-50NH5

– 57 – REFRIGERATING CYCLE DIAGRAM MODEL RAI-50NH5 RAC-50NH5 COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT REVERSING VALVE SUCTION TANK SERVICE VALVE (1/2) INDOOR UNIT SINGLE-ENDED UNION (3/8) COMPRESSOR SINGLE-ENDED UNION (1/4) SERVICE VALVE (...

[Page 48] Hitachi RAI-50NH5

– 58 – OPERATING SPECIFICATION REFERENCE OPERATION OPERATION MODE AIR DEFLECTOR PRESENT CONDITION KEY INPUT THERMO. ON (INTERNAL FAN ON) THERMO. ON (INTERNAL FAN OFF) MAIN SWITCH ON MAIN SWITCH OFF CHANGE OF OPERATION STOP DURING OPERATION DURING...

[Page 49] Hitachi RAI-50NH5

– 59 – ● The reset circuit initializes the microcomputer program when power is ON or OFF. ● Low voltage at pin 7 resets the microcomputer and Hi activates the microcomputer. ● When power “ON” 5V voltage rises and reaches 4.4V, pin 1 ...

[Page 50] Hitachi RAI-50NH5

– 60 – 2. Receiver Circuit ● 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 Fig. 3-1 Buzzer Circuit Sound wave Metal diaphrag...

[Page 51] Hitachi RAI-50NH5

– 61 – 4. Auto Sweep Motor Circuit ● Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig.4-2 are output from pins 15 – 22 of microcomputer. ● As the microcomputer’s outputs change as shown in Fig.4-2, the core ...

[Page 52] Hitachi RAI-50NH5

– 62 – 5. Room Temperature Thermistor Circuit ● Fig. 5-1 shows the room temperature thermistor circuit. 5 4 3 2 1 0 010 Room temperature (˚C) Fig. 5-2 20 30 40 0V Room temperature thermistor 0V 5V Fig. 5-1 62 A R305 C302 Microcomputer Room t...

[Page 53] Hitachi RAI-50NH5

– 63 – 7. Initial Setting Circuit (IC401) ● When power is supplied, the microcomputer reads the data in IC401 (E 2 PROM) and sets the preheating activation value and the rating and maximum speed of the compressor, etc. to their initial values. ...

[Page 54] Hitachi RAI-50NH5

– 64 – Model RAI-50NH5 1. Power Circuit ● This circuit full-wave rectifies 220-240V AC applied between terminals L and N, and boosts it to a required voltage with the active module, to create a DC voltage. The voltage becomes 260-360V when the ...

[Page 55] Hitachi RAI-50NH5

– 65 – (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-50NH5. (4) Smoothing capacitor (C010, C011) This smoothes ...

[Page 56] Hitachi RAI-50NH5

– 66 – 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 transmi...

[Page 57] Hitachi RAI-50NH5

– 67 – ● Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other. Indoor P.W.B. Outdoor P.W.B. Terminal board Terminal board CD CD D101 I/F 0V C821 R821 C822 0V 0V 0V0V 5V 5V 5V 0V 0V 0...

[Page 58] Hitachi RAI-50NH5

– 68 – Outdoor HIC 29 Pin 30 Pin Indoor microcomputer DC 35V line 49 Pin 50 Pin 100ms. Leader 33ms. 1 frame 0.7V 0V 5V 0V 5V 0V 5V 0V 35V Indoor microcomputer 4.95ms. Transmit / receive switching time 33ms. 1 frame Outdoor HIC 30 Pin 0V 29 Pin 5V...

[Page 59] Hitachi RAI-50NH5

– 69 – [Serial Communications Format during Normal Communications] (1) Outdoor microcomputer (HIC) to indoor microcomputer (2) Indoor microcomputer to outdoor microcomputer (HIC) (3) Communications waveforms 1 frame = 100ms. + 33.3ms. x 8 +...

[Page 60] Hitachi RAI-50NH5

– 70 – [ Serial Communications Data ] 7 1/0 6 1/0 5 1/0 4 1/0 3 1/0 2 1/0 1 1/0 0 1/0 7 1/0 6 1/0 5 1/0 4 1/0 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 0 3 1/0 2 1/0 1 1/0 0 1/0 Character No. Bit No. Data 0 0 0 1/0 1/0 1/0 0 1/0 0 0 1/0 1/0 1/0 1/0 1/0 OVL...

[Page 61] Hitachi RAI-50NH5

– 71 – 3. Power Module Circuit ● Fig. 3-1 shows the system power module and its peripheral circuit. The three transistors on the positive e side are called the upper arm, and the three transistors on the negative d side, the lower arm. + W U V ...

[Page 62] Hitachi RAI-50NH5

– 72 – ● 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. E F UVVW Upper arm transistor Lower arm tran...

[Page 63] Hitachi RAI-50NH5

– 73 – + U U V W — U + V — V + W — W _ + System Power Module 2 260V-360V R24 DC current (Id) detection resistor A U coil DC compressor motor V coil W coil B Fig. 3-5 ● Since current flows at point only when U+ transistor is ON, the cur...

[Page 64] Hitachi RAI-50NH5

– 74 – 4. Power Circuit for P.W.B. ● Fig. 4-1 shows the power circuit for P.W.B. and waveform at each point. 22 18 19 + D908 R917 R915 D909 R918 L903 REG1 C911 20 21 + D907 C910 R914 C912 16 17 + C903 C907 + + C914 14 13 R916 L902 35V 17V 5V F...

[Page 65] Hitachi RAI-50NH5

– 75 – (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 ap...

[Page 66] Hitachi RAI-50NH5

– 76 – 5. Reversing valve control circuit ● 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. Voltage at each point in e...

[Page 67] Hitachi RAI-50NH5

– 77 – 6. Rotor magnetic pole position detection circuit A B C D E 18 19 20 Outdoor microcomputer C605 +5V 0V HIC 0V +12V WV U C608 System power module DC brushless motor for compressor R604 R605 R606 R607 R601 R602 R603 R604 R603 R602 R608 C503 ...

[Page 68] Hitachi RAI-50NH5

– 78 – 7. Drive Circuit Fig. 7-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration. ● In low speed rotation mode (PWM range), as shown in Fig. 7-2, 0-5V chopper signal is ouput from microcomputer...

[Page 69] Hitachi RAI-50NH5

– 79 – U + V + 5V 0V W + V - W - U - U + V + 15V 0V W + V - W - U - Drive signal at point B Drive signal at point A V + U + W + V + U + V - W - U - V - W - [Low speed rotation mode] [High speed rotation mode] V + U + W + V + U + U + V + 5V 0V W...

[Page 70] Hitachi RAI-50NH5

– 80 – 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. Table 8-1 Circuit block Basic operation Peak c...

[Page 71] Hitachi RAI-50NH5

– 81 – Drive signal Chopper signal Chopper signal DC Current level DC current Detection resistor 5V DC 260V -360V Reset circuit Over-load external setting circuit Current amplified circuit Drive Circuit IP signal Reset Voltage Peak current cut o...

[Page 72] Hitachi RAI-50NH5

– 82 – (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,...

[Page 73] Hitachi RAI-50NH5

– 83 – 60 Fig. 8-6 Fig. 8-7 Voltage at microcomputer pin Rotation speed of compressor Deceleration DecelerationAcceleration Acceleration Commanded rotation speed Actual rotation speed 59 61 58 + 60 Is D104 L CT1 N R005 0V0V 0V 0V 0V0V R247 R006 C...

[Page 74] Hitachi RAI-50NH5

– 84 – ● R500, R253, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage (260- 380V) via HIC 37 and applies correction to the overload set value so the DC current is low (high) when the DC voltage is high (low)....

[Page 75] Hitachi RAI-50NH5

– 85 – 9. Temperature Detection Circuit ● The Over heat thermistor circuit detects the temperature at the surface of the compressor head, the Defrost. thermistor circuit detects the defrosting operation temperature. ● A thermistor is a negat...

[Page 76] Hitachi RAI-50NH5

– 86 – 10. Reset Circuit ● The reset circuit initializes the microcomputer program when Power is “ON” or “OFF”. ● Low voltage at pin 48 resets the microcomputer, and HI activates the microcomputer. ● Fig. 10-1 shows the reset circ...

[Page 77] Hitachi RAI-50NH5

– 87 – R297 R298 C208 R108 R107 C101 VSD RC Filter Motor coil System power module Power supply for DC fan motor from smoothing capacitor in system power module Smoothing Capacitor U V W BOARD DC Fan motor with control board ONE CHIP DRIVER IC R24...

[Page 78] Hitachi RAI-50NH5

– 88 – < 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 misconne...

[Page 79] Hitachi RAI-50NH5

– 89 – 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 12. Power Factor Control Circuit * Assuming the sam...

[Page 80] Hitachi RAI-50NH5

– 90 – SERVICE CALL Q & A Model RAI-50NH5 COOLING MODE The compressor has stopped suddenly during cooling operation. Sound of running water is heard from indoor unit during dehumidifying. Compressor occasionally does not operate during dehumi...

[Page 81] Hitachi RAI-50NH5

– 91 – AUTO FRESH DEFROSTING AUTO OPERATION NICE TEMPERATURE RESERVATION INFRARED REMOTE CONTROL After the ON/OFF button is pressed to stop heating, the outdoor unit is still working with the OPERATION lamp lighting. Fan speed does not change whe...

[Page 82] Hitachi RAI-50NH5

– 92 – OTHERS Q15 A15 Q16 A16 Q17 A17 Q18 A18 Q19 A19 The indoor fan varies among high air flow, low air flow and breeze in the auto fan speed mode. (Heating operation) This is because the cool wind prevention function is operating, and does not ...

[Page 83] Hitachi RAI-50NH5

– 93 – TROUBLE SHOOTING Model RAI-50NH5 PRECAUTIONS FOR CHECKING Power source + ~ + – ~ ACT Module + – + – N C D L Compressor motor System power module 2 Indoor unit electric parts Control P. W . B . DC35V 0V (0V) MAIN P.W.B. Power module a...

[Page 84] Hitachi RAI-50NH5

– 94 – SPM2 Smoothing capacitors RAC-50NH5 1. Turn OFF the Power supply to the outdoor unit. 2. After power is turned off, wait for 10 minutes or more. Then, remove electrical parts cover and apply soldering iron of 30 to 75W for 15 seconds or m...

[Page 85] Hitachi RAI-50NH5

– 95 – CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE Model RAI-50NH5 Does the timer lamp on the indoor unit blink? Is the compressor in the outdoor unit operating? Does the operation lamp on the indoor unit start to ...

[Page 86] Hitachi RAI-50NH5

– 96 – TROUBLESHOOTING WHEN TIMER LAMP BLINKS. Model RAI-50NH5 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Model: RAI-50NH5 No. Timer indicator flashing mode...

[Page 87] Hitachi RAI-50NH5

– 97 – SELF-DIAGNOSIS LIGHTING MODE MODEL: RAI-50NH5 0274E Pg 97-118(RAI-50NH5) 19/10/05, 3:37 PM97 ...

[Page 88] Hitachi RAI-50NH5

– 98 – 1. Power does not come on (no operation) Is AC 220-240V AC being generated between terminals L and N on the outdoor unit terminal board? Is DC 35V being generated between terminals C and D on the outdoor unit terminal board? Check the indo...

[Page 89] Hitachi RAI-50NH5

– 99 – 2. Outdoor unit does not operate (but receives remote infrared signal) 0274E Pg 97-118(RAI-50NH5) 19/10/05, 3:37 PM99 ...

[Page 90] Hitachi RAI-50NH5

– 100 – 3. Only indoor fan does not operate (other is normal) Is approx 20 V DC generated between pins 2 (blue) and 4 (red) of CN 10 when operated at high fan speed during cooling? Are pulses of approx. 33 Vp-p generated at the collectors of Q901...

[Page 91] Hitachi RAI-50NH5

– 101 – 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...

[Page 92] Hitachi RAI-50NH5

– 102 – CHECKING THE REMOTE CONTROLLER 0274E Pg 97-118(RAI-50NH5) 19/10/05, 3:37 PM102 ...

[Page 93] Hitachi RAI-50NH5

– 103 – MODEL RAI-50NH5 [No operation or abnormal operation] Is AC220-240V being supplied to terminal L and N? Is the 25A fuse normal? If the 25A fuse has blown, be aware that other parts may also be defective (mainly, varistor 2, diode stack, s...

[Page 94] Hitachi RAI-50NH5

– 104 – LD301 blinks 9 time. Communication error. Is DC 35V being output at terminals C and D? (Normally, DC 33-38.5V is output.) Yes Interface relay Coil terminal Contact terminal Is DC 35V being output across R914? Is DC 12V being supplied acro...

[Page 95] Hitachi RAI-50NH5

– 105 – Ye s N o No Ye s Ye s Ye s No No No LD301 blinks 8 time. Acceleration defect. LD301 blinks 7 time. Thermistor abnormal. Is the power module normal? Is the drive circuit normal? Is the thermistor connector disconnected? ❈ The problem ma...

[Page 96] Hitachi RAI-50NH5

– 106 – LD301 blinks 6 time. The temperature at the OH thermistor rises. LD301 blinks 5 time. Overload lower limit cut. LD301 blinks 4 time. Failure of switching. LD301 blinks 3 time. Abnormal low speed. Replace parts in the thermistor circuit. N...

[Page 97] Hitachi RAI-50NH5

– 107 – 0274E Pg 97-118(RAI-50NH5) 19/10/05, 3:37 PM107 ...

[Page 98] Hitachi RAI-50NH5

– 108 – POWER CIRCUIT Phenomenon 1 <Rotation speed does not increase> Is the DC voltage at least 350V? Is the OVL lamp lit? If the lamp is lit, it does not indicate fault, but the unit is overload status. Recheck cord, etc. of the system po...

[Page 99] Hitachi RAI-50NH5

– 109 – CHECKING THE REFRIGERATING CYCLE 1. Troubleshooting procedure (No operation, No heating, No cooling) Connect U,V,W phase leads to the power module again and operate the air conditioner. Gas leaks. Repair and seal refrigerant. Is the self-...

[Page 100] Hitachi RAI-50NH5

– 110 – HOW TO CHECK SYSTEM POWER MODULE + + +– – + + – P1 P2 U WV N1 L2 L1 + – + – – + – – P1 P2 U WV N1 L2 L1 Checking system power module using tester Set tester to resistance range (X 100) If indicator does not swing in t...