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Hitachi RAS-20CNHZ2 Service Manual

Indoor unit + outdoor unit
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SERVICE MANUAL

TECHNICAL INFORMATION

FOR SERVICE PERSONNEL ONLY
RAS-20CNHZ2
SPECIFICATIONS
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
COOLING CAPACITY
HEATING CAPACITY
DIMENSIONS
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

ROOM AIR CONDITIONER

MAY 2002
RAS-30CNHZ2
RAM-50CNHZ2
RAS-20CNHZ2 RAS-30CNHZ2
(W)
(A)
(kW)
(B.T.U.)
W
(mm)
H
D
(kg)
INDOOR UNIT + OUTDOOR UNIT
PM
RAS-20CNHZ2
RAS-30CNHZ2
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 7
HOW TO USE ---------------------------------------------------------------------- 10
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 35
MAIN PARTS COMPONENT -------------------------------------------------- 37
WIRING DIAGRAM ---------------------------------------------------------------- 39
CIRCUIT DIAGRAM --------------------------------------------------------------- 41
PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 43
BLOCK DIAGRAM ----------------------------------------------------------------- 49
BASIC MODE ----------------------------------------------------------------------- 51
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 64
TROUBLE SHOOTING ----------------------------------------------------------- 95
PARTS LIST AND DIAGRAM ------------------------------------------------- 110
DC INVERTER
DUAL
INDOOR UNIT
1ø, 220V - 230V, 50Hz
REFER TO THE SPECIFICATIONS PAGE 8.
745
798
248
265
175
168
5.5
6.5
H.A.P.M.
NO. 0148E
RAM-50CNHZ2
CONTENTS
SYSTEM MULTI (WALL TYPE)
RAM-50CNHZ2
850
650
298
43

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Summary of Contents for Hitachi RAS-20CNHZ2

  • Page 1: Table Of Contents

    PARTS LIST AND DIAGRAM ------------------------------------------------- 110 SPECIFICATIONS DC INVERTER DUAL SYSTEM MULTI (WALL TYPE) TYPE INDOOR UNIT OUTDOOR UNIT RAS-20CNHZ2 RAS-30CNHZ2 RAM-50CNHZ2 MODEL POWER SOURCE 1ø, 220V – 230V, 50Hz TOTAL INPUT TOTAL AMPERES REFER TO THE SPECIFICATIONS PAGE 8.
  • 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 operation, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally, but this noise is not abnormal for the operation. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 6: 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 7 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 8: Specifications

    SPECIFICATIONS RAS-20CNHZ2/ MODEL RAM-50CNHZ2 RAS-30CNHZ2 FAN MOTOR 20 W 40 W FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR — COMPRESSOR GW20DN8A COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (MICRO COMPUTER CIRCUIT) 3.0A FUSE (MAIN SUPPLY) FUSE (FAN MOTOR) POWER RELAY...
  • Page 9 SPECIFICATIONS FOR INDOOR UNITS COMBINATIONS WALL TYPE DC INVERTER QUADRUPLE SYSTEM MULTI TYPE COOLING AND HEATING INDOOR UNIT RAS-20CNHZ2 RAS-30CNHZ2 MODEL RAM-50CNHZ2 OUTDOOR UNIT PHASE/VOLTAGE/FREQUENCY 1ø, 220V-230V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 2.50 (1.00~3.00) 3.20 (1.00~3.30) CAPACITY (kW) (B.T.U./h)
  • Page 10 INSTALLATION HEIGHT DIFFERENCE Height difference between indoor units should not be more than 5m. Indoor unit 1 Indoor unit 2 Maximum 5 m Outdoor unit (Within ±10 m) PIPING LENGTH Indoor unit 2 Indoor unit 1 Outdoor unit (L1 + L2) = Maximum 35m Maximum piping length for one indoor unit is 25m.

  • Page 11: Names And Functions Of Each Part

    NAMES AND FUNCTIONS OF EACH PART OUTDOOR UNIT DRAIN PIPE Condensed water drain to outside. CONNECTING CORD AIR INLET (BACK, LEFT SIDE) AIR OUTLET MODEL NAME AND DIMENSIONS MODEL WIDTH (mm) HEIGHT (mm) DEPTH (mm) RAS-20CNHZ2 RAS-30CNHZ2 RAM-50CNHZ2 – 10 –...
  • Page 12 NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT RAS-20CNHZ2 AIR FILTER To prevent dust from coming into the indoor unit. (Refer page 30) INDOOR UNIT INDICATORS Light indicator showing the operating condition. (Refer page 12) FRONT PANEL (AIR INLET) HORIZONTAL DEFLECTOR...

  • Page 13: Indoor Unit Indicators

    OPERATION INDICATOR RAS-20CNHZ2 NORMAL TEMPORARY /AUTO 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.
  • Page 14 OPERATION INDICATOR RAS-30CNHZ2 TEMPORARY SWITCH Use this switch to start and stop when the remote controller does not work. SELECTOR SWITCH AUTO RESTART SWITCH In the event of power failure, the air conditioner will restart automatically in AUTO TEMPORARY the previously selected mode once the power is restored. NORMAL RESTART SWITCH...

  • Page 15: Names And Functions Of Remote Control Unit

    NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT REMOTE CONTROLLER This controls the operation of the indoor unit. The range of control is about 7 meters. If indoor lighting is controlled electronically, the range of control may be shorter. This unit can be fixed on a wall using the fixture provided. Before fixing it, make sure the indoor unit can be controlled from the remote controller.

  • Page 16: Automatic Operation

    AUTOMATIC OPERATION 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 FUNCTION selector so that the display indicates the (AUTO) mode of operation.

  • Page 17: 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. Press the FUNCTION selector so that the display indicates (HEAT).

  • Page 18: 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. START Press the (START/STOP) button. Dehumidifying operation ˚ starts with a beep. Press the button again to stop operation. STOP Press the FUNCTION selector so that the display indicates (DEHUMIDIFY).

  • Page 19: Cooling Operation

    COOLING OPERATION Use the device for cooling when the outdoor temperature is 22-42°C. If humidity is very high (over 80°C) indoors, some dew may form on the air outlet grille of the indoor unit. Press the FUNCTION selector so that the display indicates (COOL).

  • Page 20: 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.* START Press the...

  • Page 21: 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 22 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 23: How To Set The Sleep Timer

    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 24 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.

  • Page 25: Adjusting The Air Deflector

    Adjustment of the conditioned air to the left and right. Hold the vertical air deflector as shown in the figure and adjust the conditioned air to the left and right. RAS-30CNHZ2 RAS-20CNHZ2 – 24 –...

  • Page 26: How To Exchange The Batteries In The Remote Controller

    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 27 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 28 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 29: Attaching The Air Cleansing And Deodorizing Filters

    ATTACHING THE AIR CLEANSING AND DEODORIZING FILTERS RAS-20CNHZ2 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. Open the front panel. Pull up the front panel by holding it at both sides with both hands.
  • Page 30 ATTACHING THE AIR CLEANSING AND DEODORIZING FILTERS RAS-30CNHZ2 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. Open the front panel. Be sure to hold the button sides on the left and right of the front panel with both hands and pull up the front panel forward.
  • Page 31 MAINTENANCE RAS-20CNHZ2 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. AIR FILTER Clean the air filter, as it removes dust inside the room. In case the air filter is full of dust, the air flow will decrease and the cooling capacity will be reduced.
  • Page 32 MAINTENANCE RAS-30CNHZ2 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. AIR FILTER Clean the air filter, as it removes dust inside the room. In case the air filter is full of dust, the air flow will decrease and the cooling capacity will be reduced.
  • Page 33 Washable Front Panel Remove the front panel and wash with clean water. Wash it with a soft sponge. After using neutral detergent, wash thoroughly with clean water. When front panel is not removed, wipe it with a soft dry cloth. Wipe the remote controller thoroughly with a soft dry cloth.
  • Page 34 CAUTION Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD Run the unit by 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, to dry the unit.
  • Page 35 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”? Was the air filter cleaned? Does sunlight fall directly on the outdoor unit? When it does not cool well...

  • Page 36: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAS-20CNHZ2 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...
  • Page 37 MODEL RAM-50CNHZ2 Handle Handle Air outlet Air suction grille Holes for anchor bolt (2-ø12) More than More than Fixing hole Service space Notch for anchor bolt (2-ø12 Notchs) – 36 –...

  • Page 38: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT Thermostat Specifications MODEL RAS-20CNHZ2, RAS-30CNHZ2 THERMOSTAT MODEL OPERATION MODE COOL HEAT 14.3 (57.7) 24.3 (75.7) INDICATION 13.6 (56.5) 25.0 (77.0) TEMPERATURE 22.3 (72.1) 32.3 (90.1) INDICATION °C (°F) 21.6 (70.9) 33.0 (91.4) 30.3 (86.5) 40.3 (104.5) INDICATION 29.6 (85.3)
  • Page 39 COMPRESSOR MOTOR Compressor Motor Specifications MODEL RAM-50CNHZ2 COMPRESSOR MODEL GW20DN8A PHASE SINGLE RATED VOLTAGE AC 220 ~ 230 V RATED FREQUENCY 50/60 Hz POWER SOURCE FOR COMPRESSOR Vcc max = 360V POLE NUMBER WHITE CONNECTION YELLOW 20°C 2M = 1.05 (68°F) RESISTANCE VALUE 75°C...

  • Page 40: Wiring Diagram

    WIRING DIAGRAM INDOOR UNIT MODEL RAS-20CNHZ2, RAS-30CNHZ2 Connecting Cord From Terminal Outdoor Board Brown CN10 Indoor Fan Green & Motor Yellow MAIN P.W.B. Black Room Temperature Black Thermistor Gray Heat Auto Sweep Exchanger Gray Motor Thermistor Light Receiving TEST Unit P.w.b...
  • Page 41 WIRING DIAGRAM OUTDOOR UNIT MODEL RAM-50CNHZ2 – 40 –...

  • Page 42: 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 Super silent cooling SEG5 SEG20 SEG19 Door open On timer Hour up Hour down SEG0 SEG1 SEG18 SEG2 SEG17 Door shut Room temperature up...

  • Page 43: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAS-20CNHZ2 MAIN P.C.B (EH-2P) JUMPER CN10 (XH-3P) THERMAL FUSE R101 FOR TERMINAL POWER SUPPLY ZD101 ICP1 (102 C) L101 BROWN R104 L102 YELLOW INDOOR DC REG2 REG1 FAN MOTOR BLUE C105 C942 R105 L901...
  • Page 44 MODEL RAS-30CNHZ2 MAIN P.C.B (EH-2P) JUMPER CN10 (XH-3P) R101 THERMAL FUSE FOR TERMINAL POWER SUPPLY ZD101 ICP1 L101 (102 C) BROWN R104 L102 YELLOW INDOOR DC REG2 REG1 FAN MOTOR BLUE C105 C942 R105 L901 Q901 R106 CONNECTING R107 CABLE ICP2 TERMINAL R108...
  • Page 45 MODEL RAM-50CNHZ2 MOUNTING TYPE F : FILM R : RADIAL C : CERAMIC C : SMD D : ELECTROLYTIC A : AXIAL REACTOR H : HAND INSERT POWER P.W.B. S P M 2 RESISTOR CAPACITOR TRANSISTOR TERMINAL D25VB60 SPM2-CAPA 25A FUSE NF-COIL1 COMMON MODE COIL POWER RELAY RATING...

  • Page 46: Block Diagram

    BLOCK DIAGRAM INDOOR OUTDOOR MODEL RAS-20CNHZ2 MODEL RAM-50CNHZ2 Outdoor fan motor Power source1 ¿50Hz, 220-240V Wireless receive LCD wireless circuit PAM Power Magnetic relay Power module circuit Buzzer circuit Room temperature thermistor Inrush current DC compressor Protection circuit motor Operation.

  • Page 47: Basic Mode

    BASIC MODE MODEL RAM-50CNHZ2 – 51 –...
  • Page 48 New Cool Rhythm Cooling Sleep Operation Room temperature Final set temperature Minimum Minimum Minimum Minimum (Cooling/dehumidifying set Minimum 5min. 5min. 5min. 5min. Minimum 5min. 5min. 5min. 5min. 5min. 5min. 5min. temperature (+) sleep shift) Final set temperature SFCMIN (shift lower limit) (Cooling/dehumidifying set temperature (Cooling/dehumidifying set...
  • Page 49 Notes: (1) 30 seconds after the operation is started, when the room temperature is (cooling preset temperature) - (1.33˚C) or less, 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, OFF for 5 minutes and ON for 1 minute (at high humidity) or OFF for 6 minutes and ON for 1 minute (at low humidity), repeatedly according to the humidity judgement when the thermostat is turned OFF.
  • Page 50 – 57 –...
  • Page 51 – 59 –...
  • Page 52 DEFROST → reversing cycle period → Reversing valve defrost system is employed: it consists of balancing period balancing period. (1)Defrost start condition When all the following conditions are established, defrost is executed: Normal operation Heat exchange temperature is within defrost range specified by outdoor temperature and heat exchange temerature.
  • Page 53 Time chart when executing defrost (both unit 1 and unit 2 operated) Defrosting signal Unit 1 Unit 2 Unit 1 Unit 2 Unit 1 Defrosting request Unit 2 Defrosting request 30sec. Turns on for cooling Cooling output Heating output 15sec. Outdoor fan Defrosting inhibit period Balancing period [TDF415] sec.
  • Page 54 AUTO-FRESH DEFROST During heating operation is stopped, and when auto-fresh condition is established, defrost operation will be performed while operation is stopped. Auto-fresh consists of balancing period at start of defrost for [TDF414] seconds → Reverse cycle period for MAX 12 minutes. (1) Start conditions for auto-fresh When all the following conditions are established, auto-fresh is executed: Defrost request signal is present.
  • Page 55 FORCED COOLING In order to accumulate refrigerant, units operate in cooling cycle. Execution condition and operation status are shown below. [Execution condition] With neither indoor unit 1 and 2 not operated, when forced cooling switch is turned ON, forced cooling will be performed.

  • Page 56: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM Cooling, dehumidifying, defrosting ¿12.7 Indoor unit Outdoor unit Service SUCTION ¿12.7 Single-ended valve (3/8") TANK union (3/8") Reversing valve Silencer ¿9.52 ¿12.7 ¿6.35 ¿9.52 ¿12.7 Service Single-ended valve (3/8") ¿9.52 AIR FLOW union (3/8") Silencer ¿9.52 ¿6.35 ¿6.35 Flow Electric expansion...

  • Page 57: Description Of Main Circuit Operation (Indoor)

    DESCRIPTION OF MAIN CIRCUIT OPERATION (INDOOR) MODEL RAS-20CNHZ2, RAS-30CNHZ2 1. Reset Circuit Normal : Hi Reset : Lo Q202 Micro Computer AX-7M12 Fig. 1-1 Voltage 35 DC Line 5V DC Line Base of Q201 POWER ON POWER is OFF Voltage Collector of Q202 Fig.
  • Page 58 2. Receive Circuit Model: RAS-20CNHZ2 R710 R701 R709 C701 ZD701 – LIGHT Wireless input RECEIVING R705 UNIT C702 Micro computer AX-7M12 Fig. 2-1 Model: RAS-30CNHZ2 R707 C701 – LIGHT Wireless input RECEIVING R706 R705 UNIT C702 Micro computer AX-7M12 Fig. 2-2 The Light receiving unit receives an infrared signal from the wireless remote control.
  • Page 59 4. Auto Sweep Motor Circuit Auto sweep motor for horizontal air deflectors Micro computer AX-7M12 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 –...
  • Page 60 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 AX-7M12 R309 Room temp. input R310 C301 Fig. 5-1 Room temperature (ßC) Fig.
  • Page 61 7. Auto Restart / Temporary Switch Auto Restart Switch MODEL : RAS-20CNHZ2 34 X1 R706 Micro Computer AUTO RESTART (AX-7M12) NORMAL Fig. 7-1 MODEL : RAS-30CNHZ2 R602 Micro Computer AUTO RESTART (AX-7M12) NORMAL Fig. 7-2 Temporary Switch MODEL : RAS-30CNHZ2...
  • Page 62 AUTO RESTART SWITCH R709 R710 TEMPORARY SWITCH C701 ZD701 SW701 37 X1 MICRO COMPUTER 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.

  • Page 63: Description Of Main Circuit Operation (Outdoor)

    DESCRIPTION OF MAIN CIRCUIT OPERATION (OUTDOOR) Model RAM-50CNHZ2 1. Power Circuit POWER P.W.B. SWITCHING POWER P.W.B. (FOR INDOOR AND OUTDOOR P.W.B.) SWITCHING POWER P.W.B. (FOR INDOOR P.W.B.) Fig. 1-1 This circuit full-wave rectifies 220-230V AC applied between terminals L and N, and boosts it to a required voltage with the active module, to create a DC voltage.
  • Page 64 (3) Smoothing capacitor C501,C52,C503 This smoothes (averages) the voltage rectified by the diode stacks. Vd (DC Voltage) – – – C501 C502 C503 – Fig. 1-2 DC Voltage Fig. 1-3 (Approx. 330 or 360V during operation) Smoothing capacitor (C501, C502, C503) SPM2 GRN3 GRN1...
  • Page 65 (5) C001 to C005, NF COIL 1 Be sure to ground outdoor unit. There absorb electrical noise generated during If not grounded, noise filter circuit does not operate operation of compressor, and also absorb external correctly. noise entering from power line to protect eletronic parts.
  • Page 66 Fig. 2-1 shows the interface circuit used for the indoor and outdoor micro computers to communicate with each other. MAIN P.W.B. IF RECEIVE (SD1) MICRO COMPUTER (AX-7M12) IF TRANSMIT (SD0) INDOOR P.W.B. OUTDOOR P.W.B. POWER P.W.B. MAIN P.W.B. IF CLOCK MICRO COMPUTER (AX-6M00)
  • Page 67 0.7V Base of outdoor P.W.B. Q801, Q802 Outdoor micro computer pin , 72 Indoor micro computer pin 35V DC line 100ms. 33ms. Leader 1 frame Fig. 2-2 Voltages Waveforms of indoor / Outdoor Micro computers (Outdoor to Indoor Communications) Base of outdoor P.W.B. Q801, Q802 Outdoor micro computer pin , 71 Indoor micro computer pin...
  • Page 68 3. System Power Module Circuit – 76 –...
  • Page 69 DC 260-360V is input to power module and power module switches power supply current according to rotation position of magnet rotor. The switching order is as shown in Fig. 3-2. At point E: U + is ON, V – is ON (circuit in Fig. 3-1) At point F: U + is chopped (OFF), V –...
  • Page 70 System power module 260V-360V DC compressor U coil motor V coil – – – W coil DC current (Id) detection resistor Fig. 3-4 System 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.
  • Page 71 4. Power Circuit for P.W.B. Fig. 4-1 shows the power circuit for P.W.B. Switching transformer R717 D713 C718 R712 Diode stack 115V R718 D710 R703 C714 R005 C707 R714 R702 R701 C735 D709 P.EG1 D705 C716 C708 C721 D702 R708 D706 R723 C731...
  • Page 72 (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 C708 reaches the specified value, REG2 turns on and current flows to PQ8 1-2.
  • Page 73 5. Reversing valve control circuit Reversing valve D831 PQ831 Q831 Micro Computer R832 R833 R831 DC voltmeter or tester Fig. 5 1 By reversing valve control circuit you can switch reversing valve ON/OFF (Heating ON) according to instruction from indoor microcomputer and depending on operation condition. Voltage at each point in each operation condition is approximately as shown below when measured by tester.
  • Page 74 6. Rotor magnetic pole position detection circuit Inverter DC brushless motor for compressor R502 R501 R500 C205 +12V R505 R504 R503 R604 R603 R601 R602 R605 C605 R606 C606 R607 R611 R610 R609 C607 R608 Fig. 6-1 Rotor magnetic pole position detection circuit When the DC brushless motor is rotated, it also operates as power generator, generating reverse electromotive force according to number of rotations.
  • Page 75 7. Peripheral circuits of microcomputer Fig. 7-1 shows the microcomputer and its peripheral circuits. Table 7-1, the basic operations of each circuit block and Fig. 7-2, the system configuration. Outdoor Q208 Microcomputer R291 Q209 (AX-6L02) RESET terminal DC current Detection resistor R245 –...
  • Page 76 Reset Voltage Reset circuit Chopper Chopper Drive signal signal signal Drive Compressor Circuit Overload external motor judgement circuit DC330V or 360V Inverter section IP signal Peak current Current cut off circuit level Current amplified AX-6M00 circuit Detection resistor DC current Fig.
  • Page 77 8. Overload control circuit (OVL control) Overload control decelerates speed of compressor reducing load when the load to protect compressor, electronics parts and power breaker, when operation enters overload status due to increase of load for room temperature adjustment. To judge overload, DC current and set value are compared. Fig.
  • Page 78 (330V or 360V) Detection resister DC current R500 R245 R253 C205 Microcomputer (AX-6M00) D204 C220 – – R249 R247 D205 R278 R222 D104 R110 C103 R108 C105 – R221 C221 Fig. 8-3 Voltage at point of microcomputer Commanded rotation speed Rotation speed of compressor Actual rotation speed...
  • Page 79 R500 and R253 detect DC current in current circuit. Microcomputer compensates for overload set value so that the following is obtained: DC voltage: High → DC current: Low DC voltage: Low → DC current: High (Since load level is expressed by DC voltage x DC current, this is intended to perform the same load judgment even when voltage varies.) Amplification rate : low DC voltage : low...
  • Page 80 9. Reset Circuit Micro computer AX-6M00 Q208 R291 Q209 Fig. 9-1 Reset circuit performs initial setting of microcomputer program when power is turned on. Microcomputer resets program with reset voltage set to Lo, to enable operation at Hi level. Fig. 9-1 shows the reset circuit, and Fig. 9-2 shows waveforms at each point when power is turned on/ off.
  • Page 81 10. Temperature Detection Circuit O.H. thermistor Normal: 2.7V or less OH: 2.7V or more R304 Return: 2.3V or less O.H. C301 R301 Microcomputer (AX-6M00) DEF thermistor Normal: 2.4V or more OH: 2.4V or less R305 Return: 2.9V or more DEF. C302 R302 Outdoor temperature...
  • Page 82 11.Drive circuit Fig. 11-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration. Fig. 11-1 – 90 –...
  • Page 83 120° 120° 120° 120° 120° Fig. 11-2 – 91 –...
  • Page 84 12. Electric expansion valve R208 C225 CN15, 16 Microcomputer R209 IC6, 7 Valve Valve Valve Valve 5 12 13 Electric expansion valve 1 Fig. 12-1 The electric expansion valve is driven by DC 12V. Power is supplied to 1 or 2 phase winding to switch magnetic pole of winding in order to control opening degree.
  • Page 85 Outdoor DC Fan Motor control circuit DC330~360V PWB (POWER) SPM2 METAL COVER RC FILTER MOTOR COIL PWM control voltage FG Pulse BOARD PWB (MAIN) FAN LIMITER MICROCOMPUTER AX-6M00 FAN CHOP FM 60˚el This model uses DC Fan Motor which is including controller circuit into the Motor shell. This DC Fan Motor will rotate by control voltage apply to Vsp input.
  • Page 86 <Reference> When stop operation with LD301 blinks 12 times, it may be a DC Fan Motor broken. In this case, please check CN30 and CN31 connection first. It makes Fan Motor Lock also it those connectors are in misconnection. If 2A Fuse was burned it is possible that the DC Fan Motor may be damaged too. DC Fan Motor has broken when 2A Fuse was burned.
  • Page 87 TROUBLE SHOOTING CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAM-50CNHZ2 – 95 –...
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  • Page 92 PAM circuit Phenomenon 1 (Rotation speed does not increase) Is DC voltage 330V or more Check cords connected to present across tab of system power module again. Check diode stack. SPM2? If any cord is disconnected, connect correctly. Is OVL lamp lighting? Where OVL lamp lights, If phenomenon persists, this indicates over-load...
  • Page 93 OPERATION USING SERVICE SWITCH OF OUTDOOR UNIT RAM-50CNHZ2 1. Turn OFF power switch, then turn ON again. 2. Remove electrical parts box lid. 3. Press service switch for 1 second or more. (waiting at least 20 seconds after power switch is turned on.) At this time, LD303 (red) lights and unit operates in forced cooling mode.

  • Page 94: Trouble Shooting

    TROUBLE SHOOTING MODEL RAM-50CNHZ2 PRECAUTIONS FOR CHECKING System power module Power source 1ø220V-240V, 50Hz – DANGER – – – – – 1. Remenber that the Compressor motor 0V line is biased to 155-170V in (0V) reference to the ground level. Indoor unit 2.
  • Page 95 DISCHARGE PROCEDURE AND HOW TO CUT OFF POWER TO POWER CIRCUIT RAM-50CNHZ2 Caution: Voltage of about 360V is charged at both ends of smoothing capacitors 400 µF x 3. High voltage (DC 360V) is also charged at screw and terminal sactions of system power module. During continuity check for each circuit of electrical parts in outdoor unit is performed, to prevent secondary trouble, disconnect red/gray wire connected to system power module (SPM2) from diode stack.
  • Page 96 RAM-50CNHZ2 1. Outdoor unit does not operate (remote control signal can be received) In hot weather, set operation mode to cooling, room temperature to 16°C; in cold weather, set to heating mode and 32°C, and then press operation button. Remove outdoor unit cover and electrical parts box lid, and check LD301 self-diagnosis lamp.
  • Page 97 LIGHTING MODE SELF-DIAGNOSIS LAMP RAM-50CNHZ2 Location of self-diagnosis lamp – 105 –...
  • Page 98 Lighting mode self-diagnosis lamp RAM-50CNHZ2 :BLINKING :OFF SELF-DIAGNOSIS LIGHTING MODE :LIT DANGER (DC360V) SELF-DI A - DETAILS MAIN CHECK POINT GNOSI S NAME WAIT FOR TEN- RED RED MINUTE(MIN) AFTER [ 1 ] DURING OPERATION LD303(RED)LIGHTS. TURNING OFF THE POWER SWITCH WHEN NORMAL COMPRESSOR NOT MALFUNCTION...
  • Page 99 TROUBLESHOOTING OF THE SYSTEM POWER MODULE Collector BASE Element circuit Emitter Circuit diagram of the module — Terminal symbol of system module See next page for values measured by tester — L2L1 Do not disassemble the system power module when troubleshooting is performed. –...
  • Page 100 HOW TO CHECK POWER MODULE Checking power module using tester Set tester to resistance range (X 100) If indicator does not swing in the following conductivity check, the 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 power module is disconnected (open), the indicator of tester will not swing and this may assumed as normal.

  • Page 101: Checking The Refrigerating Cycle

    (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 102: Parts List And Diagram

    PARTS LIST AND DIAGRAM MODEL RAS-20CNHZ2 – 110 –...
  • Page 103 MODEL RAS-20CNHZ2 PART N0. Q’TY / UNIT PARTS NAME RAS-20CNHZ2 PMRAS-20CNH2 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-20CNHZ2 002 DRAIN PAN ASSEMBLY PMRAS-07C1...
  • Page 104 MODEL RAS-30CNHZ2 – 112 –...
  • Page 105 MODEL RAS-30CNHZ2 PART N0. Q’TY / UNIT PARTS NAME RAS-30CNHZ2 PMRAS-30CNHZ2 006 CABINET PMRAS-32CNH2 LOW-COVER PMRAS-13C6M 20W MOTOR PMRAS-09C1 TANGENTIAL FLOW FAN PMRAS-05C P-BEA ASSEMBLY PMRAS-32CNH2 BEARING COVER PMRAS-32CNH2 FAN MOTOR SUPPORT PMRAS-30CNHZ2 002 ELECTRICAL COVER PMRAS-30CNHZ2 003 DRAIN PAN ASSEMBLY PMRAS-07C1 DRAIN HOSE PMRAS-30CNHZ2 004...
  • Page 106 MODEL RAM-50CNHZ2 – 114 –...
  • Page 107 MODEL RAM-50CNHZ2 PART N0. Q’TY / UNIT PARTS NAME RAM-50CNHZ2 PMRAM-50CNHZ2 902 BASE PMRAM-50CNHZ2 901 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAM-50CNHZ2 911 CONDENSER PMRAC-128JHT REVERSING VALVE PMRAM-50CNHZ2 903 ELECTRICAL EXPANSION VALVE PMRAM-50CNHZ2 913 VALVE (2S) PMRAC-30CVP1 VALVE (3S) PMRAC-40CNH2 THERMISTOR (OH) PMRAC-25CNH2...

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