Hitachi RAM-52QH5 Service Manual
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Hitachi RAM-52QH5 Service Manual

Outdoor unit
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SERVICE MANUAL

TECHNICAL INFORMATION

FOR SERVICE PERSONNEL ONLY
RAM-52QH5
RAM-53QH5
NOTE:
This manual describes only points that differ from RAF-25, 35,
50NH5, RAD-25, 35NH5, RAD-25, 35NH5 and RAM-80QH5
(TC No. 0771EF), RAI-25, 35NH5 (PM No. 0271E), RAI-50NH5
and RAC-50NH5 (PM No. 0274E), RAK-18, 25, 35NH5 (PM
No. 0269E), RAK-50NH5 and RAC-50NH5 (PM No. 0302E)
for items not described in this manual.
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

ROOM AIR CONDITIONER

AUGUST 2008
RAM-52QH5
(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 --------------------------------------- 71
Description Of Main Circuit Operation ----------------------- 75
Trouble Shooting ---------------------------------------------------------- 106
Disassembly And Reassembly --------------------------------------- 113
Parts List And Diagram ------------------------------------------------- 116
DC INVERTER DUAL AND TRIPLE SYSTEM MULTI
OUTDOOR UNIT
1ø, 220 - 240V, 50Hz
REFER TO THE SPECIFICATIONS PAGE
850
650
298
50
NO. 0428E
RAM-52QH5
RAM-53QH5
CONTENTS
RAM-53QH5
After installation

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  • Page 1: Service Manual

    NO. 0428E RAM-52QH5 RAM-53QH5 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 MODEL RAM-52QH5 RAM-53QH5 FAN MOTOR 40 W FAN MOTOR CAPACITOR FAN MOTOR PROTECTOR COMPRESSOR JU1013DA 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-52QH5 PHESE/VOLTAGE/FREQUENCY 1ø, 220 - 240V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 5.20 CAPACITY (kW) (B.T.U./h) 17,740 COOLING TOTAL INPUT (W) 1,500 (TWO UNITS) EER (B.T.U./hW)
  • Page 8 SPECIFICATIONS FOR INDOOR UNITS COMBINATION TYPE DC INVERTER TRIPLE SYSTEM MULTI COOLING AND HEATING MODEL OUTDOOR UNIT RAM-53QH5 PHESE/VOLTAGE/FREQUENCY 1ø, 220 - 240V, 50Hz CIRCUIT AMPERES TO CONNECT (A) 5.20 CAPACITY (kW) (B.T.U./h) 17,740 COOLING TOTAL INPUT (W) 1,525 (THREE UNITS) EER (B.T.U./hW) 11.63 TOTAL AMPERES (A)
  • Page 9 DUAL SYSTEM MULTI R.A.C. RAM-52QH5 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-53QH5 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. (Reference value) * ONE UNIT INDICATED ARE ONLY FOR ONE UNIT OPERATION WHEN TWO INDOOR UNITS ARE CONNECTED.
  • Page 11 DUAL AND TRIPLE SYSTEM MULTI R.A.C. RAM-52QH5 & RAM-53QH5 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...
  • Page 12 DUAL SYSTEM MULTI R.A.C. RAM-52QH5 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 1.8+1.8 (8-12) + (8-12) 1.8+2.5 (8-12) + (10-16) 1.8+3.5...
  • Page 13 TRIPLE SYSTEM MULTI R.A.C. RAM-53QH5 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 1.8+1.8 (8-12) + (8-12) 1.8+2.5 (8-12) + (10-16) 1.8+3.5...

  • Page 14: 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 15 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 16 MODEL: RAM-52QH5 – 15 –...
  • Page 17 MODEL: RAM-53QH5 – 16 –...
  • Page 18 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 19 Connection of the connecting cords and power cord. (Outdoor unit) RAM-52QH5 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 20 Connection of the connecting cords and power cord. (Outdoor unit) RAM-53QH5 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: Construction And Dimensional Diagram

    CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAM-52QH5 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 22 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAM-53QH5 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 23: Main Parts Component

    MAIN PARTS COMPONENT FAN MOTOR Fan Motor Specifications MODEL RAM-52QH5 / RAM-53QH5 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 24 COMPRESSOR Compressor Motor Specifications MODEL RAM-52QH5 / RAM-53QH5 COMPRESSOR MODEL JU1013DA 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 – 23 –...

  • Page 25: Capacity Diagram

    CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-52QH5 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 26 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-52QH5 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 27 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-53QH5 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 28 CAPACITY DIAGRAM (RELATED TO THE AMBIENT TEMPERATURE) MODEL : RAM-53QH5 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 29 CAPACITY DIAGRAM (RELATED TO THE PIPING LENGTH) MODEL : RAM-52QH5 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) – 28 –...
  • Page 30 CAPACITY DIAGRAM (RELATED TO THE PIPING LENGTH) MODEL : RAM-53QH5 – 29 –...
  • Page 31 SOUND PRESSURE LEVEL MODEL : RAM-52QH5 / RAM-53QH5 (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 32 SOUND PRESSURE LEVEL MODEL : RAM-52QH5 / RAM-53QH5 (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 33: Wiring Diagram

    WIRING DIAGRAM OUTDOOR UNIT MODEL RAM-52QH5 REACTOR TERMINAL BOARD VARISTOR 1 NF COIL 1 COIL POWER RELAY (BRN) POWER SOURCE 25A FUSE AC220-240V GRN1 (BLU) R002 50Hz ICP RELAY (GRN + YEL) L007 – R005 DIODE STACK (BRN) C020 VARISTOR 3...
  • Page 34 WIRING DIAGRAM OUTDOOR UNIT MODEL RAM-53QH5 REACTOR TERMINAL BOARD VARISTOR 1 NF COIL 1 COIL POWER RELAY (BRN) POWER SOURCE 25A FUSE AC220-240V GRN1 (BLU) R002 50Hz ICP RELAY (GRN + YEL) L007 – R005 DIODE STACK (BRN) C020 VARISTOR 3 5A FUSE (D15VBA60) INDOOR UNIT 1...

  • Page 35: 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 – – SEG20 SEG5 Door open On timer Hour up Hour down • present time SEG0 SEG19 SEG1...
  • Page 36 CIRCUIT DIAGRAM MODEL RAM-52QH5 – 39 –...
  • Page 37 CIRCUIT DIAGRAM MODEL RAM-53QH5 – 41 –...

  • Page 38: Block Diagram

    BLOCK DIAGRAM MODEL RAM-52QH5 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...
  • Page 39 BLOCK DIAGRAM MODEL RAM-53QH5 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...
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  • Page 41 MODEL RAM-52QH5 / RAM-53QH5 PROM NO. LABEL NAME REQUIRED VALUE OF UNIT SIDE PSTARTC1$ pulse PSTARTC1K$ pulse PSTARTC2$ pulse PSTARTC2K$ pulse PSTARTC3$ pulse PSTARTC3K$ pulse PSTARTH1$ pulse PSTARTH1S$ pulse PSTARTH2$ pulse PSTARTH2S$ pulse PSTARTH3$ pulse PSTARTH3S$ pulse PMIN$ pulse DFCTPS$...
  • Page 42 [Outdoor temperature >STAROTP_C] TSKTM1_C1 [Outdoor temperature ≤STAROTP_C] TSKTM1_C2 – 49 –...
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  • Page 47 MODEL RAM-52QH5 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 48 MODEL RAM-53QH5 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 49 DEFROST Reversing valve defrost system is employed: it consists of balancing period reversing cycle period balancing period. 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. Defrost inhibit period linked to outdoor temperature has passed.
  • Page 50 MODEL RAM-52QH5 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 51 MODEL RAM-53QH5 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 52 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-52QH5 If signal is delayed, auto-fresh condition will not be established. Defrosting signal Unit 1...
  • Page 53 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 54 MODEL RAM-52QH5 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 55 MODEL RAM-53QH5 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 56 MODEL RAM-52QH5 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 57 MODEL RAM-53QH5 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 62: Description Of Main Circuit Operation

    DESCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAM-52QH5 , RAM-53QH5 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...
  • Page 63 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 – 74 –...
  • Page 64 – 75 –...
  • Page 65 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 66 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 67 3. System power Module Circuit – 78 –...
  • Page 68 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 69 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 70 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 71 – 82 –...
  • Page 72 5. Reversing valve control circuit Fig. 5-1 – 83 –...
  • Page 73 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 74 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-6V01) R291 Reset terminal DC current Detection resistor R245 IP cutter...
  • Page 75 8. Overload control circuit (OVL control circuit) Fig. 8-1 Overload Control System Configuration Fig. 8-2 – 86 –...
  • Page 76 9. Reset circuit +12V ZD201 R292 Microcomputer C224 R290 AX-6V01 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 77 10. Temperature Detection Circuit The outdoor units (this model) provides with the outdoor temperature thermistor, DEF (defrost) thermistor, 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-55QH5, Fig. 10-2 for model RAM- 65QH5, and their roles and temperature measuring points are shown as Table 10-1.
  • Page 78 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 79 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 80 11. Electric expansion valve For RAM-53QH5 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 81 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 82 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 83 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 AC220~240V flow to the L/N terminal? to the L/N terminal.
  • Page 84 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 85 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 86 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 Turn off the power source, and remove the yellow Power source abnormally.
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  • Page 89: How To Operate The Outdoor Unit Independently

    HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT MODEL RAM-52QH5 , RAM-53QH5 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 90: Trouble Shooting

    TROUBLE SHOOTING Model RAM-52QH5 , RAM-53QH5 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 91 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 92 Lighting mode self-diagnosis lamp RAM-52QH5 , RAM-53QH5 Location of self-diagnosis lamp ‚P‚R ‚P‚S – 106 –...
  • Page 93 Lighting mode self-diagnosis lamp RAM-52QH5 , RAM-53QH5 SERVICE SWITCH MAIN P.W.B. Remark : Starmark " " is only use for RAM-53QH5 – 107 –...
  • Page 94 TROUBLESHOOTING OF THE SYSTEM POWER MODULE – 108 –...
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  • Page 97 MODEL RAM-52QH5, RAM-53QH5 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 – 111 –...
  • Page 98 inlet three three (3) Cut off the three pipes at the side and bottom of Reversing valve. – 112 –...
  • Page 99 ELECTRIC EXPANSION VALVE & PIPE THERMISTOR POSITION CHARTS MODEL RAM-52QH5 MODEL RAM-53QH5 – 113 –...

  • Page 100: Parts List And Diagram

    PARTS LIST AND DIAGRAM MODEL RAM-52QH5 – 114 –...
  • Page 101 MODEL RAM-52QH5 PART N0. / UNIT PARTS NAME PMRAM-35QH5 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-70YHA1 REVERSING VALVE PMRAM-65QH4 EXPANSION VALVE COIL(W) PMRAM-65QH4 EXPANSION VALVE COIL (R) PMRAM-65QH4 VALVE (2S) PMRAM-65QH4 VALVE (3S) PMRAC-40CNH2 THERMISTOR (OH) PMRAC-25NH4...
  • Page 102 PARTS LIST AND DIAGRAM MODEL RAM-53QH5 – 116 –...
  • Page 103 MODEL RAM-53QH5 PART N0. / UNIT PARTS NAME PMRAM-35QH5 COMPRESSOR KPNT1 PUSH NUT RAC-2226HV COMPRESSOR RUBBER PMRAC-50NH4 CONDENSER PMRAC-70YHA1 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 VALVE (3S) PMRAC-40CNH2 THERMISTOR (OH)
  • Page 104 HITACHI PM NO. 0428E RAM-52QH5 RAM-53QH5 Printed in Malaysia...

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