Hitachi RAM-18QH5E Service Manual
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Hitachi RAM-18QH5E Service Manual

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SERVICE MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
RAM-18QH5E
SPECIFICATIONS
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
COOLING CAPACITY
HEATING CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
NOVEMBER 2005
(W)
(A)
(kW)
(B.T.U.)
W
H
D
(kg)
OUTDOOR UNIT
Refrigeration & Air-Conditioning Division
NO. 0276E
PM
RAM-18QH5E
REFER TO THE FOUNDATION MANUAL
SPECIFICATIONS ------------------------------------------------------------------- 5
INSTALLATION ----------------------------------------------------------------------- 8
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 12
MAIN PARTS COMPONENT --------------------------------------------------- 13
CAPACITY DIAGRAM ------------------------------------------------------------ 15
WIRING DIAGRAM ---------------------------------------------------------------- 20
CIRCUIT DIAGRAM --------------------------------------------------------------- 21
BLOCK DIAGRAM ----------------------------------------------------------------- 25
BASIC MODE ----------------------------------------------------------------------- 27
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 40
DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 42
TROUBLE SHOOTING ----------------------------------------------------------- 66
PARTS LIST AND DIAGRAM -------------------------------------------------- 82
DC INVERTER DUAL SYSTEM MULTI
OUTDOOR UNIT
RAM-18QH5E
1ø, 220 - 240V, 50Hz
REFER TO THE SPECIFICATIONS PAGE
750
570
280
40
CONTENTS
After installation

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  • Page 1: Table Of Contents

    NO. 0276E RAM-18QH5E REFER TO THE FOUNDATION MANUAL SERVICE MANUAL TECHNICAL INFORMATION CONTENTS FOR SERVICE PERSONNEL ONLY SPECIFICATIONS ------------------------------------------------------------------- 5 INSTALLATION ----------------------------------------------------------------------- 8 CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 12 MAIN PARTS COMPONENT --------------------------------------------------- 13 CAPACITY DIAGRAM ------------------------------------------------------------ 15 WIRING DIAGRAM ---------------------------------------------------------------- 20...
  • Page 2 SAFETY DURING REPAIR WORK 1. In order to disassemble and repair the unit in question, be sure to disconnect the power cord plug from the power outlet before starting the work. 2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and the replacement must be effected in correct manner according to the instructions in the Service Manual of the unit.
  • Page 3 WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS 1. Scope The standards provide for items to be generally observed in carrying and handling semiconductors in relative manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal goods such as rejected goods being returned).
  • Page 4 (6) Use a three wire type soldering iron including a grounding wire. Metal plate (of aluminium, stainless steel, etc.) Working table Resistor of 1 M (1/2W) Staple Earth wire Bare copper wire (for body earth) Fig. 3. Grounding of the working table Soldering iron Grounding wire...
  • Page 5 CAUTION In quiet operation or stopping the running, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally, but this noise is not abnormal for the operation. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from the power outlet for safety.

  • Page 6: Specifications

    SPECIFICATIONS MODEL RAM-18QH5E FAN MOTOR 40 W FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR JU1013D2 COMPRESSOR MOTOR CAPACITOR OVERLOAD PROTECTOR OVERHEAT PROTECTOR FUSE (for MICROPROCESSOR) 5.0A POWER RELAY POWER SWITCH TEMPORARY SWITCH SERVICE SWITCH TRANSFORMER VARISTOR 450NR NOISE SUPPRESSOR THERMOSTAT...
  • Page 7 SPECIFICATIONS FOR INDOOR UNITS COMBINATION TYPE DC INVERTER DUAL SYSTEM MULTI COOLING AND HEATING MODEL OUTDOOR UNIT RAM-18QH5E PHASE/VOLTAGE/FREQUENCY 1ø, 220 - 240V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 4.0 (1.50 - 4.50) CAPACITY (kW) (B.T.U./h) 13,660 (5,120 - 15,360)
  • Page 8 DUAL SYSTEM MULTI R.A.C. RAM-18QH5E COOL / HEAT CAPACITY SPEC. FOR INDOOR UNITS COMBINATIONS TO BE ABLE TO OPERATE SIMULTANEOUSLY Whichever indoor units are installed, cooling and heating capacity depends on how many and which indoor units are operating at that time.
  • Page 9 – 8 –...
  • Page 10 MODEL: RAM-18QH5E RAM-18QH5E – 9 –...
  • Page 11 – 10 –...
  • Page 12 RAM-18QH5E AC 220V~240V ONLY INDOOR 1 INDOOR 2 C2 D2 – 11 –...
  • Page 13 RAM-18QH5E – 12 –...

  • Page 14: Main Parts Component

    MAIN PARTS COMPONENT FAN MOTOR Fan Motor Specifications MODEL RAM-18QH5E POWER SOURCE DC : 360V OUTPUT 360V CONNECTION 0-6V 0-15V (Control circuit built in) 20˚C — (68˚F) RESISTANCE VALUE 75˚C — (167˚F) BLU : BLUE YEL : YELLOW BRN : BROWN...
  • Page 15 COMPRESSOR Compressor Motor Specifications MODEL RAM-18QH5E COMPRESSOR MODEL JU1013D2 PHASE SINGLE RATED VOLTAGE DC: 280-330V RATED FREQUENCY 50Hz POLE NUMBER WHITE CONNECTION YELLOW 25°C 2M = 1.063 (68°F) RESISTANCE VALUE 75°C 2M = 1.268 (167°F) WHITE YELLOW – 14 –...

  • Page 16: Capacity Diagram

    CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-18QH5E COOLING CAPACITY (ROOM TEMPERATURE 27°C) WHEN TWO INDOOR UNITS OPERATE RATING CAPACITY 4.12 4.01 4.00 3.72 3000 2000 1332 1245 1208 1050 1000 – 15 –...
  • Page 17 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-18QH5E HEATING CAPACITY (ROOM TEMPERATURE 20°C) WHEN TWO INDOOR UNITS OPERATE – 16 –...
  • Page 18 CAPACITY DIAGRAM (RELATED TO THE PIPING LENGTH) MODEL : RAM-18QH5E COOLING 1. 0 0. 9 0. 8 0. 7 0. 6 PIPING LENGTH (m) HEATING 1. 0 0. 9 0. 8 0. 7 0. 6 PIPING LENGTH (m) – 17 –...
  • Page 19 SOUND PRESSURE LEVEL MODEL : RAM-18QH5E (Heating) APPROXIMATE THRESHOLD HEARING FOR CONTINUROUS NOISE 1000 2000 4000 8000 Octave band Main wavelength [Hz] – 18 –...
  • Page 20 SOUND PRESSURE LEVEL MODEL : RAM-18QH5E (Cooling) APPROXIMATE THRESHOLD HEARING FOR CONTINUROUS NOISE 1000 2000 4000 8000 Octave band Main wavelength [Hz] – 19 –...

  • Page 21: Wiring Diagram

    WIRING DIAGRAM OUTDOOR UNIT MODEL RAM-18QH5E – 20 –...

  • Page 22: 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 Door open On timer Hour up Hour down present time • SEG0 SEG19 SEG18...
  • Page 23 PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAM-18QH5E MOUNTING PCB SET TYPE – 23 –...

  • Page 24: Block Diagram

    BLOCK DIAGRAM OUTDOOR MODEL RAM-18QH5E OUTDOOR MODEL RAM-40QH5 Outdoor fan motor PAM Power Magnetic relay Power module circuit Inrush current DC compressor Protection circuit motor Indoor Unit 1 Rotor pole position desition detector Peak current cut off circuit Peak current...

  • Page 25: Basic Mode

    BASIC MODE MODEL RAM-18QH5E heating – 27 –...
  • Page 26 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 27 heatly 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 minule (at high humidity) or OFF for 6 minutes and ON for 1 minute (at low humidity), repeatedly acoording to the humidity judgement when the thermostat is turned OFF.
  • Page 28 Table 6 Table 7 – 33 –...
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  • Page 30 DEFROST Reversing valve defrost system is employed: it consists of balancing period → reversing cycle 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 temperature.
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  • Page 32 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 Æ Reverse cycle period for MAX 12 minutes.
  • Page 33 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.
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  • Page 36: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION (OUTDOOR) Model RAM-18QH5E 1. Power Circuit Fig. 1-1 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.
  • Page 37 (3) Smoothing capacitor (C501, C502, 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 Capacitors (C501, C502, C503) SPM2 Terminal...
  • Page 38 ❈ Be sure to ground outdoor unit. (5) C001 to C005, NF COIL 1 There absorb electrical noise generated during If not grounded, noise filter circuit does not operation of compressor, and also absorb operate correctly. external noise entering from power line to protect electronic parts.
  • Page 39 Fig. 2-1 shows the interface circuit used for the indoor and outdoor micro computers to communicate with each other. (Communications from indoor micro computer to outdoor microcomputer) (Communications from outdoor micro computer to indoor microcomputer) Fig. 2-1 Indoor / outdoor interface Circuit –...
  • Page 40 0.7V Base of outdoor P.W.B. Q801, Q802 Outdoor micro computer pin 70 , 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.
  • Page 41 3. System Power Module Circuit – 47 –...
  • Page 42 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 43 System power module 260V-360V DC compressor U coil motor V coil — — — W coil DC current (Id) detection resistor Fig. 3-4 Power module circuit (U + is ON, V – is ON) Since current flows at point B only when U+ transistor is ON, the current waveform at point B becomes intermittent waveform as shown in Fig.
  • Page 44 4. Power Circuit for P.W.B. Fig. 4-1 shows the power circuit for P.W.B. Fig. 4-1 Power circuit for P.W.B. In the power circuit for P.W.B., power voltage for microcomputer, peripheral circuits, and system power module drive and, as well as DV35V, are produced by switching power circuit. Switching power circuit performs voltage conversion effectively by switching transistor IC1 to convert DC330V voltage to high frequency of about 20kHz to 200kHz.
  • Page 45 (2) During ON The drain current at IC1 increase 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 .
  • Page 46 5. Reversing valve control circuit 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 47 6. Rotor magnetic pole position detection circuit 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. This reverse electromotive force is voltage-divided by R503-R505 and R604-R011, and appears as point voltage.
  • Page 48 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. Fig. 7-1 Peripheral circuit of microcomputer (AX-6M01) Table 7-1 Circuit block Basic operation This circuit detects DC current flowing to power module: When over-current Peak current...
  • Page 49 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-6M01 circuit Detection resistor DC current Fig.
  • Page 50 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 51 Fig. 8-3 Fig. 8-4 (2) Voltage amplifier circuit Voltage amplifier circuit voltage-amplified DC current level detected by converting to voltage using detection resistor and sends this to microcomputer. Microcomputer A/D-converts it and then compares with internal data to judge over-load control. [During overload control] Voltage generated from DC current flowing to detection resistor is balanced by resistor R245 and C220, then input to pin 5 of IC4.
  • Page 52 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 judgement even when the voltage varies.) Amplification rate : low DC voltage : low...
  • Page 53 9. Reset Circuit Fig. 9-1 Reset circuit performs initial setting of the 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 waveform at each point when power is turned on/ off.
  • Page 54 10. Temperature Detection Circuit Fig. 10-1 Compressor head surface temperature is detected by OH thermistor circuit, defrost operation temperature is detected by DEF thermistor circuit, and outdoor temperature is detected by outdoor temperature thermistor circuit. Thermistor is a negative resistance element with the following characteristic: Resistance falls when temperature rises, and increases when temperature falls.
  • Page 55 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 – 61 –...
  • Page 56 Fig. 11-2 – 62 –...
  • Page 57 12. Electric expansion valve 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. Relationship between power switching direction of phase and open/close direction is shown below. When power is supplied, voltages at pins of CN 15 and CN 16 are about 0.9V;...
  • Page 58 Outdoor DC Fan Motor control circuit 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. (Voltage range: 1.7 to 7V DC) Vsp high : Faster;...
  • Page 59 < 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 if those connectors are in misconnection. If 2A Fuse was burned it is possible that the DC Fan Motor may be damaged too.

  • Page 60: Trouble Shooting

    TROUBLE SHOOTING CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS MODEL RAM-18QH5E – 66 –...
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  • Page 65 PAM CIRCUIT Phenomenon 1 (Rotation speed does not increase) Check cords connected to Is DC voltage 330V or more Check diode stack. system power module again. present across + , — tab If any cord is disconnected, of SPM2? connect correctly. If phenomenon persists, Is OVL lamp lighting? replace system power module.
  • Page 66 OPERATION USING SERVICE SWITCH OF OUTDOOR UNIT MODEL RAM-18QH5E 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 67 TROUBLE SHOOTING Model RAM-18QH5E PRECAUTIONS FOR CHECKING DANGER 1. Remenber that the 0V line is biased to 155-170V in reference to the ground level. 2. Also note that it takes about 10 minutes until the voltage fall after the power switch is turned off.
  • Page 68 DISCHARGE PROCEDURE AND HOW TO CUT OFF POWER TO POWER CIRCUIT 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. WARNING 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...
  • Page 69 RAM-40QH5 1. Outdoor unit does not operate (remote control signal can be received) – 75 –...
  • Page 70 LIGHTING MODE SELF-DIAGNOSIS LAMP RAM-18QH5E Location of self-diagnosis lamp – 76 –...
  • Page 71 Lighting mode self-diagnosis lamp RAM-18QH5E – 77 –...
  • Page 72 TROUBLESHOOTING OF THE SYSTEM POWER MODULE – 78 –...
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  • Page 75 ELECTRIC EXPANSION VALVE & PIPE THERMISTOR POSITION CHARTS MODEL RAM-18QH5E – 81 –...

  • Page 76: Parts List And Diagram

    PARTS LIST AND DIAGRAM MODEL RAM-18QH5E – 82 –...
  • Page 77 MODEL RAM-18QH5E PART N0. RAM-18QH5E Q’TY / UNIT PARTS NAME PMRAC-63CA1 2P TERMINAL PMRAC-51CA1 CABINET PMRAM-40QH5 COIL (REVERSING VALVE) PMRAM-65QH4 COMPRESSOR RAC-2226HV COMPRESSOR RUBBER PMRAM-40QH5 CONDENSER PMRAC-09CHA1 D-GRILL PMRAC-25NH4 ELECTRICAL EXPANSION COIL PMRAM-40QH5 ELECTRICAL EXPANSION COIL PMRAM-65QH4 EXPANSION VALVE PMRAC-40CNH2...
  • Page 78 HITACHI PM NO. 0276E RAM-18QH5E Printed in Malaysia...

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