NO. 0081E RAS-25CNH2 SERVICE MANUAL RAC-25CNH2 TECHNICAL INFORMATION REFER TO THE FOUNDATION MANUAL FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS --------------------------------------------------------------5 HOW TO USE -------------------------------------------------------------------6 CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------- 22 MAIN PARTS COMPONENT --------------------------------------------- 23 RAS-25CNH2 PRINTED WIRING BOARD LOCATION DIAGRAM---------------- 25...
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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.
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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).
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(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...
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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.
SPECIFICATIONS MODEL RAS-25CNH2 RAC-25CNH2 FAN MOTOR 20 W 20 W FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR G920DP5H COMPRESSOR COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE 3.15A POWER RELAY, STICK RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER 450NR VARISTOR...
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(Refer page 8) 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-25CNH2 RAC-25CNH2 – 6 –...
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OPERATION INDICATOR TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work. By setting the temporary switch, the operation is done in previously set operation mode. When the operation is done using the temporary switch after the power source is turned off and turn on again, the operation is done in automatic mode.
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4 meters. If indoor lighting is controlled electronically, the range of control may be shorter. Signal Transmission START/STOP Button Transmission Sign HITACHI Press this button to start operation. The transmission sign blinks Press it again to stop operation. when a signal has been send.
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I The device will automatically determine the mode of operation, HEAT, COOL or DEHUMIDIFY, depending on the initial room temperature. The selected mode of operation will not change when the room temperature varies. Press the (START/STOP) button HITACHI Operation start with a “beep” sound. STOP Press the (START/STOP) button...
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DEHUMIDIFYING COOLING Outdoor Temperature Room Temperature Outdoor Temperature 21°C below 16°C above 22°C above HITACHI OPERATION MODE SELECTION Every time you press the button, the mode will change as the below sequence (Auto) [ (Heat) [ (Dry) [ (Cool) °C...
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OFF Timer Reservation I Operation stop at setting time OFF TIME setting Select the OFF TIME by pressing the (OFF) HITACHI Button. Setting time will change according to the below sequence when you press the button. 0.5 hour interval 1 hour interval °C...
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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 HITACHI 1 hour 2 hours 3 hours 7 hours Sleep timer...
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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. The FAN SPEED and room temperature will be controlled as shown below.
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ADJUSTING THE AIR DEFLECTOR Adjustment of the conditioned air in the upward and downward directions. According to operation, the horizontal air deflector is automatically set to the proper angle suitable for each operation. The deflector can be swing up and down and also set to the desired angle using the “...
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HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER Remove the cover as shown in the figure and take out the old batteries. Push and pull to the direction of arrow Install the new batteries. The direction of the batteries should match the marks in the case.
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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...
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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.
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MAINTENANCE CAUTION Before the cleaning, stop operation and disconnect 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. Further, noise may occur. Be sure to clean the filter following the procedure below.
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Washable Suction Grille The suction grille remove and can wash with clean water in whole. Wash it with a soft sponge. After using neutral detergent, wash thoroughly with clean water. When it is not removed, wipe it with a soft dry cloth.
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MAINTENANCE AT BEGINNING OF LONG OFF PERIOD Running the unit setting the operation mode to (COOL), the temperature to 32°C and the fan speed to HI for about half a day on a fine day, and dry the whole of the unit. Disconnect the power plug.
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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? When it does not cool well...
CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAS-25CNH2 Top air suction grill Wireless remote controller Air suction grill Front cover Mounting plate Cabinet Discharge grill Horizontal air deflector Vertical air deflector (147) VIEWED FROM BACK Drain cap connection part (PIPE LEAD-OUT) When piping is drawn...
MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAS-25CNH2 THERMOSTAT MODEL 17.6 (63.7) INDICATION 16.6 (61.8) TEMPERATURE 25.6 (78.1) INDICATION °C (°F) 24.6 (76.3) 33.6 (92.5) INDICATION 32.6 (90.7) FAN MOTOR Fan Motor Specifications MODEL RAS-25CNH2 RAC-25CNH2 RATED VOLTAGE DC0 – 35V...
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COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAC-25CNH2 COMPRESSOR MODEL G920DP5H PHASE SINGLE RATED VOLTAGE AC 220 – 240 V RATED FREQUENCY 50 Hz POWER SOURCE FOR COMPRESSOR Vcc max = 360V POLE NUMBER WHITE CONNECTION YELLOW 20°C 2M = 3.21 (68°F) RESISTANCE VALUE 75°C...
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MODEL RAS-25CNH2 NO MARK… MAIN P. W. B RAC-25CNH2 … POWER P. W. B … ACT P. W. B RESISTOR (Ω) RESISTOR (Ω) CAPACITOR (F) CAPACITOR (F) REACTOR RETER VALUE RETER VALUE RETER VALUE RETER VALUE SYMBOL TYPE FORM SYMBOL...
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MODEL RAS-25CNH2 SYMBOL … MOUTING FORM CAPACITOR KIND … INSERT BY HAND C … CERAMIC CAPACITOR F … FILM CAPACITOR RAC-25CNH2 … CHIP D … ELECTOLYTIC CAPACITOR HEAT EXCHANGER ROOM TEMPERATURE INDOOR DC THERMISTOR THERMISTOR RESISTOR RESISTOR CAPACITOR DIODE FAN MOTOR RESISTANCE : 10kΩ...
BLOCK DIAGRAM MODEL RAS-25CNH2/RAC-25CNH2 INDOOR UNIT OUTDOOR UNIT Outdoor DC fan motor Power switch Magnetic relay Power module Power circuit Power source Inrush current DC compressor 1ø 50Hz, 220-240V Protection circuit motor DC current signal Rotor magnetic pole position detection...
DESCRIPTION OF MAIN CIRCUIT OPERATION Model RAS-25CNH2 1. Reset Circuit 35V 5V 5V 12V Q202 NORMAL RESET ZD201 – MICRO COMPUTER Fig. 1-1 Voltage 35V DC line 5V DC line Base of Q201 Power is ON Power is OFF Collector of Q202 Fig.
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2. Receive Circuit R709 R710 C701 ZD701 – LIGHT Wireless input RECEIVING R705 UNIT C702 Micro computer Fig. 2-1 The Light receiving unit receives an infrared signal from the wireless remote control. The receiver amplifies and shapes the signal and outputs it. 3.
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4. Auto Sweep Motor Circuit Auto sweep motor for horizontal air deflectors Micro computer Rotor IC501 Fig. 4-1 Auto Sweep Motor Circuit (Horizontal air deflectors) Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig. 4-2 are output from pins –...
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5. Room Temperature Thermistor Circuit Fig. 5-1 shows the room temperature The voltage at A depends on the room thermistor circuit. temperature as shown in Fig. 5-2. Room Micro temperature computer thermistor R309 Room temp. input C302 R310 Fig. 5-1 Room temperature (˚C) Fig.
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7. Temporary Switch R709 R710 TEMPORARY SWITCH C701 ZD701 SW701 37 X1 MICRO COMPUTER Fig. 7-1 Fig. 7-1 The temporary switch is used to operate the air conditoner 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.
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PWM output Voltage at I Voltage at J Output voltage Fig. 8-2 Fan Motor Set Wind Velocity and DC Voltage (between blue and red) Characteristics Mode Connector blue-red voltage (V) Rotation Speed (min Fan Speed 16.6 19.1 1,040 OVERLOAD 19.1 1,040 27.7 1,350...
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9. 12V Power Circuit R101 R104 REG1 L102 D102 R102 C102 – C105 R103 Fig. 9 — 1 DC 35V supplied from the outdoor unit is controlled by switching of regulator 1, and is smoothed by D102, L102 and C102 to produce 12V. Output voltage is divided by R102 and R103, and input to output dividing pin to control switching, so that output voltage is 12V.
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Model RAC-25CNH2 1. Power Circuit REACTOR MAIN P. W. B 0.35mH ACT MODULE TERMINAL BOARD 15A FUSE NF COIL1 NF COIL2 VARISTOR1 SURCE- R503 R502 ABSORBERA RCP RELAY C505 VARISTOR3 COIL DIODE R505 STACK Fig. 1-1 This circuit full-wave rectifies 220-240V AC applied between terminals A and B, and boosts it to a required voltage with the active module, to create a DC voltage.
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(3) Smoothing capacitor (C501) This smoothes (averages) the voltage rectified by the diode stacks. (DC voltage) – C501 – 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 DC voltage connection of test equipment terminals.
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2. Indoor/Outdoor Interface Circuit The interface circuit superimposes an interface signal on the 36V DC line supplied from the outdoor unit to perfom communications between indoor and outdoor units. This circuit consists of a transmiting circuit which superimposes an interface signal transmit from the micro computer on the 36V DC line and a transmiting circuit which detects the interface signal on the 36V DC line and outputs it to the micro computer.
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Fig. 2-1 shows the interface circuit used for the indoor and outdoor micro computers to communicate with each other. R812 C805 R813 – IF transmit C808 output (SDO) C806 MICRO COMPUTER R810 C801 R802 IF receive input (SDI) R811 I/F 0V –...
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DC 260-380V 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 –...
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Power module 260V-380V DC compressor U coil motor V coil – – – W coil DC current (Id) detection resistor 6DI15S Fig. 3-4 Power module circuit (U + is ON, V – is ON) Since current flows at point B only when U+ transistor is ON, the current waveform at point B becomes intermittent waveform as shown in Fig.
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4. Power Circuit for P.W.B. Fig. 4-1 shows the power circuit for P.W.B. and waveform at each point. +17V R218 D213 C218 TRANS FORMER D210 C207 D209 C214 R204 D208 R505 R203 C201 C213 R202 R201 D201 D204 +12V C215 D205 D202 R208...
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(2) During ON The drain current at IC1 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 C208 reaches the specified value, REG2 turns on and current flows to PQ8 1-2.
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5. Reversing valve control circuit I/F 36V 8J-HIC Reversing valve D701 PQ701 Q701 R705 R233 MICRO COMPUTER R706 DC voltmeter or tester I/F 0V Fig. 5 — 1 ❈ Since the reversing valve is differential pressure system, even when reversing valve is ON (collector voltage of Q701 is about 0.8V normally), compressor rotation speed instructed by indoor microcomputer exceeds 3300min - , signal at pin 5 of microcomputer changes, and collector voltage of Q701 will be about...
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6. Rotor Magnetic Pole Position Detection Circuit +12V R101 R102 R103 C106 C104 C105 C101 C102 C103 R104 R105 R106 –5V Voltage at point about 260V-380V Voltage at point 0.6V Voltage at point Voltage at point B - transis- C - transis- B + transis- C + transis- tor ON...
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7. Drive Circuit (1) Upper Arm Drive Circuit Fig. 7-1 shows the upper arm drive circuit. The circuit configuration is completely the same for phases A, B and C. Power module R401 R407 R404 Bu + U + phase C404 Eu + D401 D402...
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When pin of the micro computer then goes "Lo" [ "Hi", a photocoupler between PQ2 pins 1 and 2 turns off and the reverse bias current flows to C401 [ power module’s Eu + terminals [ Bu + terminals [ R404 [ PQ2 to cut off the upper arm transistors. (Fig.7-3) R401 R404 R407...
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(2) Lower Arm Drive Circuit Fig. 7-4 shows the lower arm drive circuit. The circuit configuration is completely the same for phases A, B and C. Power module R411 R414 Bu - U - phase R412 R415 Bv - V - phase R413 R416 R417...
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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. Outdoor micro computer (AX-8J01) RESET Power module negative – To lower arm terminal drive circuit DC current...
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DC current Chopper signal Reset voltage Reset circuit Reset signal Peak current cut off Trip signal synthesis circuit circuit Chopper signal DC260V Ip signal Power -360V module Compressor motor (AX-8J01) DC current level Drive Voltage amp. circuit signal Detection resistor DC current Fig.
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(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.
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Detection resister (260-360V) DC current 8J-HIC R508 R507 Micro computer C515 – – D002 – Fig. 8-6 Voltage at micro computer pin Rotation speed of compressor Commanded rotation speed Actual rotation speed Deceleration Acceleration Deceleration Acceleration Fig. 8-7 . Voltage amp. circuit The voltage amp.
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R507, R508, R5 detect the DC voltage at the power circuit. The micro computer 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, R229, R230, R231 are provided to perform the same overload judgement even when the voltage varies.) Amplification : low...
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9. Trip Signal Synthesis Circuit Fig. 9-1 shows the trip signal synthesis circuit. This circuit uses the upper and lower arm transistor drive signals to modulate the chopper signal or stops the drive signal, according to the presence or absence of the Ip cut signal and reset signal. Q304 Reset circuit R315...
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10. Temperature Detection Circuit O.H. thermistor Normal 2.7V or less Over heat 2.7V or more Reset 2.3V or less O.H. R512 Micro computer DEF. thermistor (AX-8J01) Normal 2.4V or more Over heat 2.4V or less Reset 2.9V or more DEF. R513 Outdoor temperature thermistor...
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11. Reset Circuit 8J-HIC +12V Micro computer (AX-8j01) Q302 Q301 To trip signal synthesis circuit Fig. 11-1 Reset circuit performs initial setting of the microcomputer program before power is turned on. Microcomputer resets program with reset voltage set to Lo, and program can be operated with Hi. Fig.
SERVICE CALL Q & A Model RAS-25CNH2 RAC-25CNH2 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.
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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.
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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.
TROUBLE SHOOTING Model RAS-25CNH2 / RAC-25CNH2 PRECAUTIONS FOR CHECKING Power source 1ø220V-240V, 50Hz DANGER – – – 1. Remenber that the – 0V line is biased to Compressor motor 155-170V in reference to the (0V) ground level. Indoor unit electric parts 2.
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1. Turn off the power switch of the indoor unit or unplug its power cord from the AC outlet. 2. After turning power switch off, wait for at least 10 minutes, and then remove the electrical unit cover. Fit a 30-75 W soldering iron to the receptacles of white and black lead wires on the smoothing capacitor for at least 15 seconds, to discharge the voltage at the smoothing capacitor.
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CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE [ MODEL RAS-40CNH1/RAC-40CNH1, RAS-50CNH1/RAC-50CNH1 ] Timer lamp Does the timer or dehumidifying lamp on See "Troubleshooting when the timer lamp the indoor unit blink? blinks". Check the outdoor electrical parts. Set to room temperature 16°C in the Dehumidifying cooling mode or to 32°C in the heating lamp...
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CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAC-25CNH2 – 73 –...
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PAM (POWER ACTIVE MODULE) CIRCUIT Phenomenon 1 <Rotation speed does not increase> Recheck cord, etc. of the Is the DC voltage at least 260V? ACT 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 ACT module.
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Reinproof cover (transparent) Be sure to replace the rainproof cover after checking (rainwater would enter if it is not installed). – 79 –...
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MODEL RAS-25CNH2 PART N0. Q’TY / UNIT PARTS NAME RAS-25CNH2 PMRAS-25CNH2 CABINET PMRAS-25CNH2 LOW-COVER PMRAS-25CNH2 20W MOTOR PMRAS-25CNH2 TANGENTIAL FLOW FAN PMRAS-25CNH2 P-BEA ASSEMBLY PMRAS-25CNH2 BEARING COVER PMRAS-25CNH2 FAN MOTOR SUPPORT PMRAS-25CNH2 ELECTRICAL COVER PMRAS-25CNH2 DRAIN PAN ASSEMBLY PMRAS-25CNH2 DRAIN HOSE PMRAS-25CNH2 FRONT COVER ASS’Y...
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MODEL RAC-25CNH2 PART N0. Q’TY / UNIT PARTS NAME RAC-25CNH2 RA-226 O.L.R. COVER RA-226 COVER SUPPORT PMRAC-05CV FAN MOTOR SUPPORT PMRAC-25CNH2 20W MOTOR PMRAC-25CNH2 PROPELLER FAN PMRAC-25CNH2 CABINET PMRAC-05CV ELECTRICAL COVER ASSEMBLY PMRAC-05CV SIDE PLATE (R) PMRAC-05CV SIDE PLATE (L) PMRAC-05CV HANDLE PMRAC-05CV...