Hitachi RAM-55QH4 Service Manual
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Hitachi RAM-55QH4 Service Manual

Hitachi RAM-55QH4 Service Manual

Room air conditioner
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SERVICE MANUAL

TECHNICAL INFORMATION

FOR SERVICE PERSONNEL ONLY
RAM-55QH4
RAM-65QH4
NOTE:
This manual describes only points that differ from RAF-25,
50NH4, RAD-25, 40QH4 and RAM-70, 80QH4 (TC No.
0757EF), RAK-25, 35, 50NH4 (TC No. 0761EF), RAD-25,
40NH4, RAI-25, 40NH4 (TC No. 0763EF) for items not
described in this manual.
TYPE
MODEL
TOTAL INPUT
TOTAL AMPERES
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

ROOM AIR CONDITIONER

JUNE 2004
(W)
(A)
(kW)
(B.T.U.)
W
H
D
(kg)
Refrigeration & Air-Conditioning Division
PM
REFER TO THE FOUNDATION MANUAL

SPECIFICATIONS ------------------------------------------------------------------- 5

Installation ---------------------------------------------------------------------- 14
Construction And Dimensional Diagram ---------------------- 21
Main Parts Component --------------------------------------------------- 23
CAPACITY DIAGRAM ------------------------------------------------------------- 25
Wiring Diagram ----------------------------------------------------------------- 33
Circuit Diagram ---------------------------------------------------------------- 37
Block Diagram ------------------------------------------------------------------ 43
Basic Mode ------------------------------------------------------------------------ 45
REFRIGERATING CYCLE DIAGRAM ---------------------------------------- 73
Description Of Main Circuit Operation ------------------------ 77
Trouble Shooting ---------------------------------------------------------- 108
Disassembly And Reassembly --------------------------------------- 115
Parts List And Diagram ------------------------------------------------- 118
DC INVERTER DUAL SYSTEM MULTI
OUTDOOR UNIT
RAM-55QH4
1ø, 220 - 240V, 50Hz
REFER TO THE SPECIFICATIONS PAGE
850
650
298
50
NO. 0217E
RAM-55QH4
RAM-65QH4
CONTENTS
RAM-65QH4
After installation

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Questions and answers

Rob Belli
March 29, 2025

I got in contact a couple of days ago and was told I would have a call back but have not heard anything. I am replacing a consumer unit that includes a circuit supplying a Hitachi RAM-65QH4 air conditioner. It is currently protected by a 16A type B (overcurrent protection type) MCB. Ideally the circuit going forwards would have RCD protection on it. What RCD type is required? E.g. type A, type B... Could I put it on a type A (RCD type) RCBO or do I need to put it on a type B RCD?

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Summary of Contents for Hitachi RAM-55QH4

  • Page 1: Service Manual

    NO. 0217E RAM-55QH4 RAM-65QH4 SERVICE MANUAL REFER TO THE FOUNDATION MANUAL TECHNICAL INFORMATION CONTENTS FOR SERVICE PERSONNEL ONLY SPECIFICATIONS ------------------------------------------------------------------- 5 INSTALLATION ---------------------------------------------------------------------- 14 CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------------- 21 MAIN PARTS COMPONENT --------------------------------------------------- 23 CAPACITY DIAGRAM ------------------------------------------------------------- 25 WIRING DIAGRAM ----------------------------------------------------------------- 33...
  • 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 RAM-55QH4 RAM-65QH4 MODEL 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...
  • Page 7 SPECIFICATIONS FOR INDOOR UNITS COMBINATION TYPE DC INVERTER DUAL SYSTEM MULTI COOLING AND HEATING MODEL OUTDOOR UNIT RAM-55QH4 PHESE/VOLTAGE/FREQUENCY 1ø, 220 - 240V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 5.40 (1.50 - 5.90) CAPACITY (kW) (B.T.U./h) 18,430 (5,120 - 20,130)
  • Page 8 SPECIFICATIONS FOR INDOOR UNITS COMBINATION TYPE DC INVERTER TRIPLE SYSTEM MULTI COOLING AND HEATING MODEL OUTDOOR UNIT RAM-65QH4 PHESE/VOLTAGE/FREQUENCY 1ø, 220 - 240V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 6.30 (1.50 - 6.60) CAPACITY (kW) (B.T.U./h) 21,510 (5,120 - 22,530) COOLING TOTAL INPUT (W) 2,095 (200 - 2,200)
  • Page 9 DUAL SYSTEM MULTI R.A.C. RAM-55QH4 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 10 TRIPLE SYSTEM MULTI R.A.C. RAM-65QH4 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. C O O L I N G H E A T I N G POSSIBLE...
  • Page 11 DUAL SYSTEM MULTI R.A.C. RAM-55QH4 INDOOR UNITS COMBINATIONS TO BE ABLE TO INSTALL Two indoor units can be installed with one outdoor unit. And total nominal cooling capacity should not be more than 7.5kW NOMINAL CAPACITY (kW) SUITABLE ROOM SIZE (m...
  • Page 12 TRIPLE SYSTEM MULTI R.A.C. RAM-65QH4 INDOOR UNITS COMBINATIONS TO BE ABLE TO INSTALL Two or three indoor units can be installed with one outdoor unit. And total nominal cooling capacity should not be more than 9.0kW NOMINAL CAPACITY (kW) SUITABLE ROOM SIZE (m COOLING INDOOR UNIT at one unit operation...
  • Page 13 DUAL SYSTEM MULTI R.A.C. RAM-55QH4 CONNECTING POSISION TO BE ABLE TO INSTALL CONNECTING POSITION ON OUTDOOR UNIT POSSIBLE COMBINATIONS SUITABLE ROOM SIZE (VALVE DIAMETER) TO INSTALL TO INSTALL (mm) (kW) No.1 No.2 6.35/9.52D 6.35/9.52D 2.5+2.5 (12-15) + (12-15) 2.5+3.5 (11-14) + (14-18) 2.5+4.0...
  • Page 14 TRIPLE SYSTEM MULTI R.A.C. RAM-65QH4 CONNECTING POSISION TO BE ABLE TO INSTALL CONNECTING POSITION ON OUTDOOR UNIT POSSIBLE COMBINATIONS SUITABLE ROOM SIZE (VALVE DIAMETER) TO INSTALL TO INSTALL (mm) (kW) No.1 No.2 No.3 6.35/9.52D 6.35/9.52D 6.35/9.52D 2.5+2.5 (12-15) + (12-15) 2.5+3.5 (11-14) + (14-18) 2.5+4.0...

  • Page 15: Installation

    INSTALLATION PIPE LENGTH (1) Total 35m maximum pipe length. (2) Pipe length for one indoor unit : maximum 25m. Indoor unit 1 Indoor unit 2 Outdoor unit HIGHT DIFFERENCE (1) Hight : maximum ± 10m (2) Hight difference between each indoor unit ≤ 5m. Indoor unit Indoor unit Maximum 5m...
  • Page 16 INSTALLATION PIPE LENGTH (1) Total 45m maximum pipe length. (2) Pipe length for one indoor unit : maximum 25m. Indoor unit 1 Indoor unit 2 Indoor unit 3 Outdoor unit HIGHT DIFFERENCE (1) Hight : maximum ± 10m (2) Hight difference between each indoor unit ≤ 5m. Indoor unit Indoor unit Indoor unit...

  • Page 17: Connecting The Pipe

    MODEL: RAM-55QH4 Flare adaptor for piping One unit of 2.5kW, 3.5kW or 4.0kW The flare adaptor for piping is required depending on combination of indoor units. • ø9.52 (3/8") ø12.7 (1/2") parts number TA261D-4 001 One unit of 2.5kW, 3.5kW, 4.0kW or 5.0kW (5kW unit: Optional flare adaptor for piping is necessary) •...
  • Page 18 MODEL: RAM-65QH4 Flare adaptor for piping One unit of 2.5kW, 3.5kW or 4.0kW The flare adaptor for piping is required depending on combination of indoor units. • ø9.52 (3/8") ø12.7 (1/2") One unit of 2.5kW, 3.5kW, 4.0kW or 5.0kW parts number TA261D-4 001 One unit of 2.5kW, 3.5kW, 4.0kW or 5.0kW (5kW unit: Optional flare adaptor for piping is necessary) •...
  • Page 19 1. Remove flare nut from service valve. 2. Apply refrigerant oil to flare nut sections of servicevalve and pipings. 3. Match center of piping to large diameter side service valve and tank assembly, and tighten flarenut first by hand, then securely tighten using torque wrench. 4.
  • Page 20 Connection of the connecting cords and power cord. (Outdoor unit) RAM-55QH4 WARNING Connecting cord should be connected according to Fig.1, that the Indoor unit No. shall match with terminal board No. • of Outdoor unit. • Be sure to fix the connecting cord with the band as shown below. Otherwise water leakage causes short circuit or faults.
  • Page 21 Connection of the connecting cords and power cord. (Outdoor unit) RAM-65QH4 WARNING Connecting cord should be connected according to Fig.1, that the Indoor unit No. shall match with terminal board No. • of Outdoor unit. • Be sure to fix the connecting cord with the band as shown below. Otherwise water leakage causes short circuit or faults. Bind connecting cords to Terminal indications make them fit between the...

  • Page 22: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAM-55QH4 Unit: mm Handle Indoor unit 1 Service valve (ø6.35) Indoor unit 1 Service valve (ø9.52) Air outlet Indoor unit 2 Air suction Service valve (ø6.35) grille Indoor unit 2 Holes for anchor bolt Service valve (ø9.52) (2-ø12)
  • Page 23 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAM-65QH4 Unit: mm Indoor unit 1 Service valve (ø6.35) Indoor unit 1 Service valve (ø9.52) Handle Indoor unit 2 Service valve (ø6.35) Indoor unit 2 Service valve (ø9.52) Air outlet Indoor unit 3 Air suction Service valve (ø6.35) grille Indoor unit 3...

  • Page 24: Main Parts Component

    MAIN PARTS COMPONENT FAN MOTOR Fan Motor Specifications MODEL RAM-55QH4 / RAM-65QH4 POWER SOURCE DC : 140-330V OUTPUT 140-330V CONNECTION 0-6V 0-15V (Control circuit built in) 20˚C — (68˚F) RESISTANCE VALUE 75˚C — (167˚F) BLU : BLUE YEL : YELLOW...
  • Page 25 COMPRESSOR Compressor Motor Specifications MODEL RAM-55QH4 / RAM-65QH4 COMPRESSOR MODEL JU1013D2 SINGLE PHASE 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 – 24 –...

  • Page 26: Capacity Diagram

    CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-55QH4 COOLING CAPACITY ( ROOM TEMPERATURE 27˚C ) WHEN TWO INDOOR UNITS OPERATE RATING CAPACITY 5. 55 5. 42 5. 40 5. 00 5. 10 3000 1920 2000 1795 1740 1520...
  • Page 27 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-55QH4 HEATING CAPACITY ( ROOM TEMPERATURE 20˚C ) WHEN TWO INDOOR UNITS OPERATE 8. 0 MAX CAPACITY 7. 0 OUTDOOR UNIT RATING WITHOUT FROST CAPACITY 6. 0 5. 0 OUTDOOR UNIT 4.
  • Page 28 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-65QH4 COOLING CAPACITY ( ROOM TEMPERATURE 27˚C ) WHEN THREE INDOOR UNITS OPERATE RATING CAPACITY 6. 50 6. 32 6. 30 5. 85 5. 95 3000 2240 2095 2030 2000 1765 1240 1000 AMBIENT TEMP (˚C)
  • Page 29 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-65QH4 HEATING CAPACITY ( ROOM TEMPERATURE 20˚C ) WHEN THREE INDOOR UNITS OPERATE 8. 0 MAX CAPACITY 7. 0 OUTDOOR UNIT RATING WITHOUT FROST CAPACITY 6. 0 5. 0 4. 0 OUTDOOR UNIT WITH FROST 3.
  • Page 30 CAPACITY DIAGRAM (RELATED TO THE PIPING LENGTH) MODEL : RAM-55QH4 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) – 29 –...
  • Page 31 CAPACITY DIAGRAM (RELATED TO THE PIPING LENGTH) MODEL : RAM-65QH4 – 30 –...
  • Page 32 SOUND PRESSURE LEVEL MODEL : RAM-55QH4 / RAM-65QH4 (Heating) APPROXIMATE THRESHOLD HEARING CONTINUROUS NOISE 1000 2000 4000 8000 [ H z ] O c t a v e b a n d M a i n w a v e l e n g t h...
  • Page 33 SOUND PRESSURE LEVEL MODEL : RAM-55QH4 / RAM-65QH4 (Cooling) APPROXIMATE THRESHOLD HEARING CONTINUROUS NOISE 1000 2000 4000 8000 [ H z ] O c t a v e b a n d M a i n w a v e l e n g t h...

  • Page 34: Wiring Diagram

    WIRING DIAGRAM MODEL RAM-55QH4 OUTDOOR UNIT REACTOR TERMINAL BOARD VARISTOR 1 NF COIL 1 COIL POWER RELAY (BRN) POWER SOURCE 25A FUSE AC220-240V GRN1 R002 (BLU) 50Hz ICP RELAY (GRN + YEL) L007 – R005 DIODE STACK (BRN) C020 VARISTOR 3...
  • Page 35 WIRING DIAGRAM MODEL RAM-65QH4 OUTDOOR UNIT REACTOR TERMINAL BOARD VARISTOR 1 NF COIL 1 COIL POWER RELAY (BRN) POWER SOURCE 25A FUSE AC220-240V GRN1 R002 (BLU) 50Hz ICP RELAY (GRN + YEL) L007 – R005 DIODE STACK (BRN) C020 VARISTOR 3 5A FUSE (D15VBA60) INDOOR UNIT 1...

  • Page 36: 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 37 CIRCUIT DIAGRAM MODEL RAM-55QH4 – 39 –...
  • Page 38 CIRCUIT DIAGRAM MODEL RAM-65QH4 – 41 –...

  • Page 39: Block Diagram

    BLOCK DIAGRAM MODEL RAM-55QH4 Outdoor Unit Power source single phase 50Hz, 220-240V compressor System Magnetic relay Power Module Inrush current protection relay SPM driver Rotor position detector EEPROM Overload current detector Expansion valve 1 Expansion valve Fan motor drive circuit...
  • Page 40 BLOCK DIAGRAM MODEL RAM-65QH4 Outdoor Unit Power source single phase 50Hz, 220-240V compressor System Magnetic relay Power Module Inrush current protection relay SPM driver Rotor position detector EEPROM Overload current detector Expansion valve 1 Expansion valve Fan motor Expansion valve 2 drive circuit drive circuit fan motor...
  • Page 41 – 45 –...
  • Page 42 MODEL RAK-25NH4 RAK-35NH4 RAK-50NH4 REQUIRED VALUE REQUIRED VALUE REQUIRED VALUE PROM LABEL NAME OF UNIT SIDE OF UNIT SIDE OF UNIT SIDE RTOTSA 2.00 ˚C 2.00 ˚C 2.00 ˚C WMAX _ M 5300 5000 4500 WMAX2 _ M 5300 5000 4500 WSTD _ M 4000...
  • Page 43 Table 1 Fan speed by mode RAF-25NH4 RAF-50NH4 MODEL REQUIRED VALUE REQUIRED VALUE N O . LABEL NAME Operation OF UNIT SIDE OF UNIT SIDE Fan speed mode Label name mode 09C RTOTSA 2.00 ˚C 2.00 ˚C FWSS _ M WMAX _ M 5300 min 4500 min...
  • Page 44 MODEL RAM-55QH4 RAM-65QH4 REQUIRED VALUE REQUIRED VALUE PROM LABEL NAME OF UNIT SIDE OF UNIT SIDE RTOTSA 5.00 ˚C 5.00 ˚C WMAX _ M 5300 4500 WMAX2 _ M 5300 4500 WSTD _ M 4000 3700 WJKMAX _ M 3700...
  • Page 45 MODEL RAD-25NH4 RAD-40NH4 REQUIRED VALUE REQUIRED VALUE PROM LABEL NAME OF UNIT SIDE OF UNIT SIDE RTOTSA 2.00 ˚C 2.00 ˚C WMAX _ M 5300 4500 WMAX2 _ M 5300 4500 WSTD _ M 4000 4000 WJKMAX _ M 3600 4000 WBEMAX _ M 3200...
  • Page 46 MODEL RAM-55QH4 / RAM-65QH4 PROM NO. LABEL NAME REQUIRED VALUE OF UNIT SIDE PSTARTC1$ PSTARTC1K$ PSTARTC2$ PSTARTC2K$ PSTARTH$ PSTARTH2$ PMIN$ DFCTPS$ DFCTPN$ DFSPPS$ DFPSMX$ PCLOSH$ CMAX1 5400 CMAX2 6100 CMAX3 6200 WMAX1 6200 WMAX2 6200 WMAX3 6200 STAROTP_C ˚C SDRCT1_C1...
  • Page 47 [Outdoor temperature >STAROTP_C] TSKTM1_C1 [Outdoor temperature ≤STAROTP_C] TSKTM1_C2 – 53 –...
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  • Page 52 MODEL RAM-55QH4 Expansion valves The expansion valves are initialized when power is supplied. The valve for unit 1 is fully closed (–520 pulses), and then that for unit 2 is fully opened (480 pulses). The valve for unit 2 is fully closed (–520 pulses).
  • Page 53 MODEL RAM-65QH4 Expansion valves The expansion valves are initialized when power is supplied. The valve for unit 1 is fully closed (–520 pulses), and then that for unit 2 is fully opened (480 pulses). The valve for unit 2 is fully closed (–520 pulses), and then that for unit 3 is fully opened (480 pulses).
  • Page 54 Unit being operated : [DFCTPS] 30 seconds before balancing period is finished Synchronized with step-up of rotation speed of compressor, opened by [DFSPPS] pulses and reaches MAX opening degree [DEFSMX] when rotation speed of compressor reaches [DEFMAX]. RAM-55QH4, RAM-65QH4 DEFROST TEMPERATURE DEFROST TEMPERATURE DEFROST...
  • Page 55 MODEL RAM-55QH4 Time chart when executing defrost ( unit 1 and unit 2 operated) Defrosting signal Unit 1 Unit 2 Unit 1 Unit 2 Unit 1 Defrosting request Unit 2 Defrosting request Turns on for cooling T_4BEN_DEF Cooling output Heating output Outdoor temperature ≥...
  • Page 56 MODEL RAM-65QH4 Time chart when executing defrost ( unit 1, unit 2 and unit 3 operated) Defrosting signal Unit 1 Unit 2 Unit 3 Unit 1 Unit 2 Unit 3 Unit 1 Defrosting request Unit 2 Defrosting request Unit 3 Defrosting request Turns on for cooling...
  • Page 57 MAX opening degree [DEFSMX] when rotation speed of compressor reaches [DEFMAX]. Note Shifted to auto-fresh in defrost mode when operation is stopped. All indoor units must be stopped to fulfill condition for auto-fresh. MODEL RAM-55QH4 If signal is delayed, auto-fresh condition will not be established. Defrosting signal Unit 1...
  • Page 58 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.
  • Page 59 MODEL RAM-55QH4 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 60 MODEL RAM-65QH4 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, 2 and 3 not operated, when forced cooling switch is turned ON, forced cooling will be performed. Always operation status of indoor units are monitored and forced cooling is inhibited when operation of any unit is detected.
  • Page 61 MODEL RAM-55QH4 PROCESSING AT OVERHEAT THERMISTOR (OH) HIGH TEMPERATURE Restriction Start Conditions If any expansion valve is operated at 480 pulses and the OH temperature > [NDOWN_ON], the compressor speed will be reduced at a rate of 100 min /30 seconds.
  • Page 62 MODEL RAM-65QH4 PROCESSING AT OVERHEAT THERMISTOR (OH) HIGH TEMPERATURE Restriction Start Conditions If any expansion valve is operated at 480 pulses and the OH temperature > [NDOWN_ON], the compressor speed will be reduced at a rate of 100 min /30 seconds. This reduced rotation speed is based on the speed when the reduction started, and will be maintained until the reduction is finished.
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  • Page 67: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAM-55QH4, RAM-65QH4 Power Circuit REACTOR POWER P.W.B.(1/2) SPM2 COIL POWER RELAY 25A FUSE NF COIL VARISTOR 1 R002 R003 SURGE TB11 ICP RELAY ABSORBER TB11 R001 TB11 L007 GRN1 C103 R009 GRN2 L006 GRN3...
  • Page 68 SMOOTHING SPM (SYSTEM POWER MODULE) CAPACITOR DIODE STACK 2P TERMINAL BOARD SERVICE SWITCH ‚ O E E E E E‚ ` SWITCHING CONTROL P.W.B. REACTOR POWER P.W.B. SELF-DIAGNOSIS LAMPS – 78 –...
  • Page 69 – 79 –...
  • Page 70 Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other. R813 R812 C802 Q803 R810 IF transmit output (SDO) C804 R811 Micro computer C821 R821 IF receive input (SDI) I/F 0V C822 D101 Terminal board Indoor P.W.B.
  • Page 71 0.7V Base of outdoor P.W.B Q801, Q802 , Q803 Outdoor micro computer lndoor micro computer SDO Pin SDI Pin 35V DC line 33ms. 100ms. 1 frame Leader 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 lndoor micro computer SDO Pin...
  • Page 72 3. System power Module Circuit – 82 –...
  • Page 73 Upper arm transistor Time Lower arm transistor V – – U – Fig. 3-2 Switching order of power module transistor chopped U transistor ON Voltage point 320-360V Chopping period Upper arm transistor Current at Fig. 3-3 Voltage waveform at each point –...
  • Page 74 System Power Module 320-360V DC compressor motor U coil – – V coil – W coil DC current (Id) detection resistor Fig. 3-4 System Power module circuit (U + is OFF, V – is ON) SMOOTHING SPM (SYSTEM POWER MODULE) CAPACITOR DIODE STACK 2P TERMINAL...
  • Page 75 4. Power Supply Circuit Fig. 4-1 shows the power circuit. Fig. 4-1 Power circuit for P.W.B. There are two switching power supply in Power PWB. Switching power supply 1 is generating the secondary power for control circuits and DC35V indoor unit 1. Switching power supply 2 is generating the DC12V for expansion valve and DC35V for indoor unit 2 and 3.
  • Page 76 – 86 –...
  • Page 77 5. Reversing valve control circuit CN10 Reversing valve D831 PQ831 Q831 Micro R833 R832 computer R831 DC voltmeter or multimeter Fig. 5-1 – 87 –...
  • Page 78 6. Rotor magnetic pole position detection circuit lnverter DC brushless motor for compressor R502 +12V R505 R504 R503 R501 R604 R603 R602 R601 R605 C605 R606 C606 R607 R608 R609 R610 C607 R611 Fig. 6-1 Rotor magnetic pole position detection circuit –...
  • Page 79 7. Peripheral circuit 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. C224 Outdoor R290 Microcomputer Q209 Q205 (AX-6S00) R291 Reset terminal DC current Detection resistor R245 IP cutter...
  • Page 80 8. Overload control circuit (OVL control circuit) Translation AX-6S00 micro computer To power module negative terminal Judgement OVL with respect to Motor control externally set process (R503) value Detection resistor Judgement OVL Voltage amp. according to the rotation convarter circuit speed (Internal judgement) Primary...
  • Page 81 9. Reset circuit +12V ZD201 R292 Microcomputer C224 R290 AX-6S00 R291 Q205 Q209 R293 R294 C223 R295 To trip signal composing circuit Fig. 9-1 12V line 5V line Reset voltage Time 12V line 5V line Reset voltage Time Fig. 9-2 –...
  • Page 82 OH (overheat) thermistor and electric expansion valve thermistor so that they detect the temperatures of the unit and control the system. The circuit of the thermistors is shown as Fig. 10-1 for model RAM-55QH4, Fig. 10-2 for model RAM- 65QH4, and their roles and temperature measuring points are shown as Table 10-1.
  • Page 83 Table 10-1 Name and Role of each thermistor Name Connector No Measuring Point Role If the temperature of the compressor OH thermistor Compressor head rises abnormally (118˚C), the compressor will be stopped. The temperature is used to decide the operation of the valve. The thermistors decide the defrost DEF thermistor Heat exchanger...
  • Page 84 When the connectors of the thermistors are disconnected or the thermistors is open or short, LD301 (red) lights and LD302 (red) blinks so that they indicate troubled parts. Combinations of LD301 and LD302 are set up for indicating troubled thermistors. The correspondences between the number of blink time and troubled parts are shown as Table 10-3. Look in the table (LD301 and LD302 blink) for troubled parts, and if the disconnections of them are checked out, they are replaced.
  • Page 85 11. Electric expansion valve For RAM-65QH4 only. Table 11-1 The electric expansion valve is driven by DC 12V. Power is supplied to 1 or 2 phases of 4-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.
  • Page 86 12. Power Factor Control Circuit Power factor is controlled by almost 100%. (Effective use of power) With IC in ACT module, control is performed so that input current waveform will be similar to waveform of input voltage. I (input current) input voltage V (input voltage) Effective...
  • Page 87 INSPECTING OUTDOOR ELECTRICAL PARTS Check to see that the LED is either on or blinking. Carry out inspections by examining the on/blinking status of LEDs 301-304. LED number LD301 LD302 LD303 LD304 Status Checkpoints Name Diagnosis Diagnosis Communications Operation lamp 1 lamp 2 lamp lamp...
  • Page 88 Inspection method 1 LED on Insert the power source, and check to see that the Follow "Inspecting external electrical parts" and check LED is on. the cause of the problem. LED off Connect a commercial-use 220-240V power source Is AC230V flowign to the L/N terminal? to the L/N terminal.
  • Page 89 Inspection method 2 Check the number of times LD301 blinks. LD301: Blinks once The power source or some other reason may have caused the microcomputer Reset stop to reset. Replace the control P.W.B. if the LED blinks once and then stops frequently during operation.
  • Page 90 Outdoor fan rotates LD301: Blinks five times Insert the power source and operate, and then check to see that the outdoor fan is Overload stop rotating Outdoor fan rotates, but soon stops. The protection circuit may cause the fan to stop when Replace the fan motor.
  • Page 91 O.K. AC196V-265V LD301: Blinks ten times Check the power source voltage Check the wiring (diode stack (terminal board, L/N terminal) Power source voltage blue/yellow/gray/red) abnormally abnormally noise N.G. AC196V or less or AC265V or more Danger! Quickly turn off the power Less than AC196V Power source abnormally.
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  • Page 94: How To Operate The Outdoor Unit Independently

    HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT MODEL RAM-55QH4, RAM-65QH4 1. Turn the Power switch off and then turn on again. 2. Remove the electrical parts cover. 3. Press the service switch for one second or more (wait for at least 30 seconds after turning the power source switch on).

  • Page 95: Trouble Shooting

    TROUBLE SHOOTING Model RAM-55QH4 RAM-65QH4 PRECAUTIONS FOR CHECKING Power source 1 ø 220-240V, 50Hz DANGER 1. Remember that the 0V line is biased to 162V in reference to the ground level. 2. Also note that it takes about 10 minutes...
  • Page 96 Discharge procedure and how to cut off power to power circuit Caution DANGER Voltage of about 360V is charged at both ends of smoothing capacitor 330 µ F x 3. High voltage (DC 360V) is also charged at screw and terminal sections of system power module. During continuity check of each circuit of electrical parts in outdoor unit is performed, to prevent secondary trouble, disconnect red/gray wire connected to system power module (SPM) from diode stack.
  • Page 97 Lighting mode self-diagnosis lamp RAM-55/65QH4 Location of self-diagnosis lamp ‚P‚R ‚P‚S – 110 –...
  • Page 98 Lighting mode self-diagnosis lamp RAM-55/65QH4 SERVICE SWITCH MAIN P.W.B. Remark : Starmark " " is only use for RAM-65QH4 – 111 –...
  • Page 99 TROUBLESHOOTING OF THE SYSTEM POWER MODULE – 112 –...
  • Page 100 – 113 –...
  • Page 101 – 114 –...
  • Page 102 MODEL RAM-65QH4 SMOOTHING SPM (SYSTEM POWER MODULE) CAPACITOR 2P TERMINAL DIODE STACK BOARD SERVICE SWITCH ‚ O E E E E E‚ ` SWITCHING CONTROL P.W.B. REACTOR POWER P.W.B. SELF-DIAGNOSIS LAMPS – 115 –...
  • Page 103 inlet three three (3) Cut off the three pipes at the side and bottom of Reversing valve. – 116 –...
  • Page 104 ELECTRIC EXPANSION VALVE & PIPE THERMISTOR POSITION CHARTS MODEL RAM-55QH4 MODEL RAM-65QH4 – 117 –...

  • Page 105: Parts List And Diagram

    PARTS LIST AND DIAGRAM MODEL RAM-55QH4 – 118 –...
  • Page 106 MODEL RAM-55QH4 PART N0. RAM-55QH4 Q’TY / UNIT PARTS NAME PMRAM-65QH4 BASE PMRAM-65QH4 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-25NH4 REVERSING VALVE PMRAM-65QH4 EXPANSION VALVE COIL (W) PMRAM-65QH4 EXPANSION VALVE COIL (R) PMRAM-65QH4 VALVE (2S) PMRAM-65QH4 VALVE (3S)
  • Page 107 PARTS LIST AND DIAGRAM MODEL RAM-65QH4 – 120 –...
  • Page 108 MODEL RAM-65QH4 PART N0. RAM-65QH4 Q’TY / UNIT PARTS NAME PMRAM-65QH4 BASE PMRAM-65QH4 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-25NH4 REVERSING VALVE PMRAM-65QH4 EXPANSION VALVE COIL (W) PMRAM-65QH4 EXPANSION VALVE COIL (R) PMRAM-65QH4 EXPANSION VALVE COIL (B) PMRAM-65QH4 VALVE (2S) PMRAM-65QH4...
  • Page 109 HITACHI PM NO. 0217E RAM-55QH4, RAM-65QH4 Printed in Malaysia...

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Ram-65qh4

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