Hitachi RAS-18MH1 Service Manual
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Hitachi RAS-18MH1 Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
RAS-18MH1
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
JANUARY 2014
RAC-18MH1
INDOOR UNIT
RAS-18MH1
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)
INDOOR UNIT + OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
PM
RAS-18MH1/RAC-18MH1
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ---------------------------------------------------------------------4
HOW TO USE -------------------------------------------------------------------------6
CONSTRUCTION AND DIMENSIONAL DIAGRAM ----------------------- 28
MAIN PARTS COMPONENT ---------------------------------------------------- 30
WIRING DIAGRAM ----------------------------------------------------------------- 33
CIRCUIT DIAGRAM ---------------------------------------------------------------- 35
PRINTED WIRING BOARD LOCATION DIAGRAM ---------------------- 41
BLOCK DIAGRAM ------------------------------------------------------------------ 44
BASIC MODE ------------------------------------------------------------------------ 45
REFRIGERATING CYCLE DIAGRAM----------------------------------------- 59
AUTO SWING FUNCTION ------------------------------------------------------- 60
DESCRIPTION OF MAIN CIRCUIT OPERATION ------------------------- 61
TROUBLE SHOOTING ------------------------------------------------------------ 78
PARTS LIST AND DIAGRAM ---------------------------------------------------- 98
DC INVERTER (WALL TYPE)
1 PHASE, 50 Hz, 220-230V
1,560 (155 ~ 2,200)
7.15 ~ 6.85
5.00 (0.9 ~ 5.2)
17,070 (3,072 ~ 17,740)
1,660 (155 ~ 2,200)
7.60 ~ 7.30
6.00 (0.9 ~ 8.1)
20,480 (3,072 ~ 27,649)
780
280
215
9.5
NO. 0558E
CONTENTS
OUTDOOR UNIT
RAC-18MH1
850
650
298
45
After installation

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  • Page 1: Table Of Contents

    NO. 0558E RAS-18MH1/RAC-18MH1 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION FOR SERVICE PERSONNEL ONLY CONTENTS SPECIFICATIONS ---------------------------------------------------------------------4 HOW TO USE -------------------------------------------------------------------------6 CONSTRUCTION AND DIMENSIONAL DIAGRAM ----------------------- 28 MAIN PARTS COMPONENT ---------------------------------------------------- 30 WIRING DIAGRAM ----------------------------------------------------------------- 33 CIRCUIT DIAGRAM ---------------------------------------------------------------- 35...
  • 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). 2.
  • 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 Screw stop at the screwed...
  • Page 5 CAUTION In quiet or stop operation, slight fl owing 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 MODEL RAS-18MH1 RAC-18MH1 47 W FAN MOTOR PWM DC35V FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR JU1015DA – COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR YES (INTERNAL) OVERHEAT PROTECTOR 3.15A FUSE (for MICROPROCESSOR) POWER RELAY POWER SWITCH TEMPORARY SWITCH TEST/SERVICE SWITCH...
  • Page 7 Figure showing the installation of Indoor and Outdoor unit MODEL RAS-18MH1 / RAC-18MH1 Be sure to completely seal any gap with putty. The indoor piping should be insulated with the enclosed insulation pipe. (If the insulator is insufficient, please use commersial products).
  • Page 8 SAFETY PRECAUTION Please read the “Safety Precaution” carefully before operating the unit to ensure correct usage of the unit. ● Pay special attention to signs of “ Warning” and “ Caution”. The “Warning” section contains matters which, ● if not observed strictly, may cause death or serious injury. The “Caution” section contains matters which may result in serious consequences if not observed properly.
  • Page 9 PRECAUTIONS DURING OPERATION The product shall be operated under the manufacturer specifi cation 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 ●...
  • Page 10 1 year depending on application requirements. 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-18MH1 RAC-18MH1 – 8 –...
  • Page 11 INDOOR UNIT INDICATORS FILTER LAMP When the device is operated for a total of about 200 hours, the FILTER lamp lights to indicate that it is time to clean the fi lter. The lamp goes out when the “ (AUTO SWING)”...
  • Page 12 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 fi xed on a wall using the fi xture provided. Before fi xing it, make sure the indoor unit can be ●...
  • Page 13 VARIOUS FUNCTIONS ■ Auto Restart Control If there is a power failure, operation will be automatically restarted when the power is resumed with previous ● operation mode and airfl ow direction. (As the operation is not stopped by remote controller.) If you intend not to continue the operation when the power is resumed, switch off the power supply.
  • Page 14 HEATING OPERATION Use the device for heating when the outdoor temperature is under 21°C. ● When it is too warm (over 21°C), the heating function may not work in order to protect the device. In order to keep reliability of the device, please use this device above -15°C of the outdoor temperature. ●...
  • Page 15 DEHUMIDIFYING OPERATION Use the device for dehumidifying when the room temperature is over 16°C. When it is under 15°C, the dehumidifying function will not work. Press the FUNCTION selector so that the display indicates (DEHUMIDIFY). The FAN SPEED is set at LOW or SILENT. Set the desired room temperature with the TEMPERATURE button (the display indicates the setting).
  • Page 16 COOLING OPERATION Use the device for cooling when the outdoor temperature is -10~ 43°C. If in doors humidity is very high (80%), some dew may form on the air outlet grille of the indoor unit. Press the FUNCTION selector so that the display indicates (COOL).
  • Page 17 FAN OPERATION You can use the device simply as an air circulator. Use this function to dry the interior of the indoor unit at the end of summer. Press the FUNCTION selector so that the display indicates (FAN). Press the (FAN SPEED) button.
  • Page 18 HOW TO SET THE TIMER Press the (TIME) button. After you change the batteries; TIME OFF TIMER ON TIMER Press the (OFF-TIMER) button, until the (OFF) mark blinks on the display. RESERVE CANCEL You can set the device to turn off at the preset time.
  • Page 19 Press the Set the current time with the Press the (TIME) button again. (TIME) button. TIMER control button. The time indication starts lighting instead of fl ashing. ● The time indication will disappear automatically in 10 second. ● To check the current time setting, press the (TIME) button twice.
  • Page 20 HOW TO SET THE SLEEP TIMER Set the current time at fi rst 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...
  • Page 21 HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER Remove the cover as shown in the fi gure and take out the old Push and pull to the batteries. direction of arrow Install the new batteries. The direction of the batteries should match the marks in the case. CAUTION 1.
  • Page 22 THE IDEAL WAYS OF OPERATION Suitable Room Temperature Install curtain or blinds Warning It is possible Freezing temperature to reduce heat is bad for health and entering a waste of electric room through power. windows. Ventilation Effective Usage Of Timer At night, please use the “OFF or ON timer Caution operation mode”, together with your wake...
  • Page 23 Federation the operating life of a domestic air conditioner is determined as 7 years from the date of manufacture. Considering the high quality, reliability and high level of operating safety of “Hitachi” products, the actual operating life may considerably exceed the offi cial one.
  • Page 24 ATTACHING THE AIR PURIFYING FILTERS CAUTION Cleaning and maintenance must be carried out only by qualifi ed 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 ●...
  • Page 25 MAINTENANCE CAUTION Cleaning and maintenance must be carried out only by qualifi ed service personal. Before cleaning, stop operation and switch off the power supply. 1. PRE-FILTER Clean the pre-fi lter, as it removes dust inside the room. In case the pre-fi lter is full of dust, the air fl ow will decrease and the cooling capacity will be reduced.
  • Page 26 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 27 CAUTION Cleaning and maintenance must be carried out only by qualifi ed service personal. Before cleaning, stop operation and switch off the power supply. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD Running the unit setting the operation mode to (FAN) and ●...
  • Page 28 AFTER SALE SERVICE AND WARRANTY WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS CONDITION CHECK THE FOLLOWING POINTS If the remote controller is not Do the batteries need replacement? ● transmitting a signal. Is the polarity of the inserted batteries correct? ●...
  • Page 29 Note Avoid to use the room air conditioner for cooling operation when the outside temperature is below ● –10°C (14°F). The recommended maximum and minimum operating temperatures of the hot and cold sides should be as below: Cooling Heating Minimum Maximum Minimum Maximum...

  • Page 30: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAS-18MH1 – 28 –...
  • Page 31 CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR RAC-18MH1 – 29 –...

  • Page 32: Main Parts Component

    MAIN PARTS COMPONENT THERMOSTAT (Room Temperature Thermistor) Thermostat Specifi cations MODEL RAS-18MH1 THERMOSTAT MODEL COOL HEAT OPERATION MODE 16.7 (62.1) 20.0 (68.0) INDICATION 16.0 (60.8) 20.7 (69.3) TEMPERATURE 24.7 (76.5) 28.0 (82.4) INDICATION °C (°F) 24.0 (75.2) 28.7 (83.7) 32.7 (90.9) 36.0 (96.8)
  • Page 33 COMPRESSOR MOTOR Compressor Motor Specifi cations RAC-18MH1 MODEL JU1015DA COMPRESSOR MODEL PHASE SINGLE RATED VOLTAGE AC 220 ~ 230 V RATED FREQUENCY 50 Hz POLE NUMBER CONNECTION 20°C 2M = 1.579 (68°F) RESISTANCE VALUE 75°C 2M = 2.149 (167°F) CAUTION When the Air Conditioner has been operated for a long time with the capillary tubes clogged or crushed or with too little refrigerant, check the color of the refrigerant oil inside the compressor.

  • Page 34: Wiring Diagram

    WIRING DIAGRAM MODEL RAS-18MH1 / RAC-18MH1 – 33 –...

  • Page 35: Circuit Diagram

    CIRCUIT DIAGRAM Remote Control – 35 –...
  • Page 36 CIRCUIT DIAGRAM RAS-18MH1 – 37 –...
  • Page 37 CIRCUIT DIAGRAM MODEL RAC-18MH1 – 39 –...

  • Page 38: Printed Wiring Board Location Diagram

    PRINTED WIRING BOARD LOCATION DIAGRAM RAS-18MH1 – 41 –...
  • Page 39 MODEL RAC-18MH1 P.W.B. MAIN – 42 –...
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  • Page 43 Table 1 Mode data fi le RAS-18MH1 LABEL NAME VALUE WMAX 4400 min –1 WMAX2 4400 min –1 WSTD 4000 min –1 WBEMAX 2600 min –1 –1 CMAX 4400 min –1 CSTD 4100 min –1 CKYMAX 2500 min CJKMAX 2900 min –1...
  • Page 44 Note: 1. See the data in Table 1 on page 47 for each constant in capital letters in the diagrams. 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 corresponding compressor rpm (calculated value in Table 2) larger than CMAX.
  • Page 45 Cooling Sleep Operation Notes: The sleep operation starts when the sleep key is pressed. When the sleep key is set, the maximum compressor speed is limited, and the indoor fan is set to “sleep Lo”. 30 minutes after the sleep key is set, the sleep shift of temperature starts, and upper shift is made at least 6 times. If 25˚C is not reached after 6 shifts, shifts repeat unit 25˚C is reached.
  • Page 46 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 47 Notes: 1. See the data in Table 1 on page 47 for each constant in capital letters Notes: in the diagrams. Condition for entering into Hot Dashed mode. When fan set to “Hi” or “Auto mode” and i) Indoor temperature is lower than 18°C, and ii) outdoor temperature is lower than 10°C, and iii) Temperature difference between indoor temperature and set temperature has a corresponding compressor rpm (calculated value in Table 3) larger than WMAX.
  • Page 48 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. The maximum sleep shift of set temperature is 5°C, and the minimum is 12°C.

  • Page 49: Refrigerating Cycle Diagram

    REFRIGERATING CYCLE DIAGRAM MODEL RAS-18MH1 / RAC-18MH1 – 59 –...
  • Page 50 – 60 –...

  • Page 51: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAS-18MH1 1. Reset Circuit Fig. 1-1 Fig. 1-2 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.
  • Page 52 2. Receiver Circuit Fig. 2-1 The light receiver unit receives the infrared signal from the wireless remote control. The receiver amplifi es ● and shapes the signal and outputs it. 3. Buzzer Circuit Fig. 3-1 Buzzer Circuit When the buzzer sounds, an approx. ●...
  • Page 53 4. Auto Sweep Motor Circuit 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. Fig.4-2 Microcomputer Output Signals As the microcomputer’s outputs change as shown in Fig.4-2, the core of the auto sweep motor is excited ●...
  • Page 54 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. 6. Heat exchanger temperature thermistor circuit The circuit detects the indoor heat ●...
  • Page 55 7. Initial Setting Circuit (IC401) When power is supplied, the microcomputer reads the data in IC401 or IC402 (E PROM) and sets the ● preheating activation value and the rating and maximum speed of the compressor, etc. to their initial values.
  • Page 56 DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAC-18MH1 – 66 –...
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  • Page 59 3. Reversing valve control circuit – 69 –...
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  • Page 61 ( WHT) – 71 –...
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  • Page 64: Service Call Q & A

    SERVICE CALL Q & A – 74 –...
  • Page 65 – 75 –...
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  • Page 68: Trouble Shooting

    TROUBLE SHOOTING – 78 –...
  • Page 69 DISCHARGE PROCEDURE AND METHOD TO STOP ENERGIZE THE POWER CIRCUIT – 79 –...
  • Page 70 – 80 –...
  • Page 71 CHECKING THE INDOOR TIMER LAMP IF BLINKING 1 TIME – 81 –...
  • Page 72 CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE MODEL RAS-18MH1 – 82 –...
  • Page 73 TROUBLESHOOTING WHEN TIMER LAMP BLINKS. MODEL RAS-18MH1 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink. SELF-DIAGNOSIS LIGHTING MODE Blinking of Timer lamp Reason for indication Possible cause Reversing valve defective (1) Reversing valve defective...
  • Page 74 CHECKING INDOOR UNIT ELECTRICAL PARTS MODEL RAC-18MH1 1. Power does not come on (no operation) – 84 –...
  • Page 75 2. Outdoor unit does not operate (but receives remote infrared signal) – 85 –...
  • Page 76 3. Only indoor fan does not operate (other is normal) 4. Air defl ector does not move (others are normal) 5. All systems stop from several seconds to several minutes after operation is started (all indicators are also off) – 86 –...
  • Page 77 6. Check the main P.W.B (power circuit) – 87 –...
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  • Page 82 1. Switch OFF main power supply. 2. Short circuit between JW001 and JW002. 3. Switch ON main power supply – LD302 will blink 1 time. 4. (Within 3 minutes) Press Test/Service Switch for 1 second or more. 5. Self-diagnosis result will be shown – LD303 will ON (LIT) and LD301 will be blinking. Then refer to diagnosis table 2.
  • Page 83 – 93 –...
  • Page 84 – 94 –...
  • Page 85 SELF-DIAGNOSIS LIGHTING MODE – 95 –...
  • Page 86 CHECKING THE REMOTE CONTROLLER – 96 –...
  • Page 87 – 97 –...

  • Page 88: Parts List And Diagram

    PARTS LIST AND DIAGRAM INDOOR UNIT MODEL : RAS-18MH1 – 98 –...
  • Page 89 MODEL RAS-18MH1 RAS-18MH1 – 99 –...
  • Page 90 PARTS LIST AND DIAGRAM OUTDOOR UNIT MODEL : RAC-18MH1 – 100 –...
  • Page 91 MODEL RAC-18MH1 PART N0. Q’TY / UNIT PARTS NAME RAC-18MH1 PMRAC-X18CXT SV-COVER-AS PMRAC-50YH7 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-70YHA1 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-X13CX OVERLOAD RELAY COVER PMRAC-50YH7A...
  • Page 92 HITACHI RAS-18MH1/RAC-18MH1 PM NO. 0558E Printed in Malaysia...

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