Hitachi RAC-14EH2 Service Manual Download Page 52 | Manualshive

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(1) IS OVL
Current transformer CT1 reads the input flowing current and detected to the microcomputer as a voltage
signal. Receiving this, the microcomputer converts it to a digital signal and compares it with the internal
data to judge whether or not overload control is required.
Fig. 6-3 shows the rotation speed control. When the voltage at pin

u

of the microcomputer exceeds

the set value, the microcomputer decreases the rotation speed of the compressor and reduces the
load.

(2) ID OVL
Fig. 6-2. The filter consisting of R245 and C217 removes high harmonic frequencies from the voltage
generated by the current flowing to Detection resistor; R245 and C217 average the voltage. This voltage
is then input to IC4 pin

5

and supplied to microcomputer pin

t

. The microcomputer compares this

input with the set value, and if the input exceeds the set value, it enters overload control status.

The set Value is determined by the amplification of the voltage amp. circuit

Amplification : high

→

DC current : low

Amplification : low

→

DC current: high

Fig. 6-4 shows the rotation speed control. When the voltage at pin

t

of the microcomputer exceeds the

set value, the microcomputer decreases the rotation speed of the compressor and reduces the load.

Fig. 6-4

Fig. 6-2

Fig. 6-3

Judgment value according to rotation speed
(internal judgment value)

Rotation speed

DC current

Decelerating

Accelerating

Accelerating

Actual rotation speed

Command rotation speed

Decelerating

Voltage at microcomputer pin

Rotation speed of compressor

IPM

11

42

R003

R004

R514

R513

P

29

32

35

37

0V

Q501

R613

R612

0V

0V

R906

R905

C91

9

N

5V

0V

0V

V d

I p

I d

I S

Reset

Reset output

Microcomputer

0V

R252

R288

IC5

1

2

3

0V

5V

C215

R289

D208

R287

C204

R285

C226

R292

R284

R286

0V 0V 0V

12V

0V

R222

CN4A

CN4B

R221

C010

D204

C218

C224

C210

0V

0V

R248

IC4

7

6

5

R249

R241

R608

C222

D204

5V

0V

5V

0V

0V

R245

C217

R24

7

R005

D001

0V

0V

0V

0V

CT1

C009

R006

Power P.W.B.

Detection
Resistor

59

17

60

61

56

48

1

DC Current

Direct Current

Main P.W.B.

61

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Summary of Contents for RAC-14EH2

Page 1: ...IONAL DIAGRAM 15 MAIN PARTS COMPONENT 17 WIRING DIAGRAM 19 CIRCUIT DIAGRAM 20 BLOCK DIAGRAM 22 BASIC MODE 23 REFRIGERATING CYCLE DIAGRAM 29 DESCRIPTION OF MAIN CIRCUIT OPERATION 30 SERVICE CALL Q A 58 TROUBLE SHOOTING 61 Procedure for Disassembly and Reassembly 87 PARTS LIST AND DIAGRAM 89 RAS 14EH2 RAC 14EH2 RAC 14EH2 COOLING HEATING OUTDOOR UNIT INDOOR UNIT 780 280 220 9 5 548 35 1 PHASE 50 Hz 2...

Page 2: ...s for use in repairs or inspection should be accurately calibrated in advance 7 In installing the unit having been repaired be careful to prevent the occurence of any accident such as electrical shock leak of current or bodily injury due to the drop of any part 8 To check the insulation of the unit measure the insulation resistance between the power cord plug and grounding terminal of the unit The...

Page 3: ...goods should be handled in the same way Fig 1 Conductive Container IC A conductive polyvinyl bag IC Conductive sponge 2 When any part is handled uncovered in counting packing and the like the handling person must always use himself as a body earth Make yourself a body earth by passing one M ohm earth resistance through a ring or bracelet 3 Be careful not to touch the parts with your clothing when ...

Page 4: ...ul not to have the test probes of the measuring instrument shortcircuit a load circuit or the like Bare copper wire for body earth Working table Resistor of 1 M 1 2W Earth wire Fig 3 Grounding of the working table Metal plate of aluminium stainless steel etc Staple Screw stop at the screwed part using a rag plate Soldering iron Grounding wire Fig 4 Grounding a soldering iron 07K394_RAS 14EH2_001 0...

Page 5: ... and heating operation does not start for 3 minutes it is not abnormal and this is the result of the operation of IC delay circuit This IC delay circuit ensures that there is no danger of blowing fuse or damaging parts even if operation is restarted accidentally 5 This room air conditioner should not be used at the cooling operation when the outside temperature is below 10 C 14 F 6 This room air c...

Page 6: ...ICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL 40 W NO NO NO ASC092CD A8JK YES YES 3 0A G4A NO NO YES NO 450NR YES YES IC NO WITHOUT REFRIGERANT BECAUSE COUPLING IS FLARE TYPE UNIT PIPES MAX 20m REFRIGERANT CHARGING VOLUME Refrigerant 410A RAC 14EH2 870g RAS 14EH2 PWM DC35V NO NO NO NO NO NO NO YES NO NO NO NO YES IC YES YES 07K394_RAS 14EH2_001 01...

Page 7: ...ical shock heat generation or fire PROHIBITION Do not put objects like thin rods into the panel of blower and suction side because the high speed fan inside may cause danger Do not bundle the power cable pull it put something on it heat it process it or put it between things Breakage of the power cable may result Use of a damaged cable may cause an electrical shock or a fire PROHIBITION PROHIBITIO...

Page 8: ...formed warm air blows RAC 14EH2 RAC 10EH2 07K162_RAS 10_14EH2_En 2007 10 29 14 04 4 5 NAMES AND FUNCTIONS OF EACH PART INDOOR UNIT INDICATIONS TIMER LAMP Orange This lamp lights when the timer is working FILTER LAMP Green When the device is operated for a total of about 200 hours the FILTER lamp lights indicates that it is time to clean the filter The lamp goes out when the AUTO SWING button is pr...

Page 9: ...tically determine the mode of operation HEAT or COOL depending on the current room temperature When AUTO is first selected the device will determine the current room temperature and select the proper operation mode accordingly When the air conditioner has adjusted the room s temperature to the near preset temperature it will begin to monitor operation If the room temperature subsequently changes t...

Page 10: ...Defrosting will be performed about once an hour when frost forms on the heat exchange of the outdoor unit for 5 10 minutes each time During defrosting operation the operation lamp blinks in cycle of 3 seconds on and 0 5 second off The maximum time for defrosting is 20 minutes If the piping length used is longer than usual frost will likely to form 9 DEHUMIDIFYING OPERATION Use the device for dehum...

Page 11: ... room temperature with the TEMPERATURE buttons the display indicates the setting The temperature setting and the actual room temperature may vary somewhat depending on conditions 3 As the settings are stored in memory in the remote controller you only have to press the START STOP button next time 11 Press the START STOP button Fan operation starts with a beep Press the button again to stop operati...

Page 12: ...ting of the current time is now complete AM PM PM PM Example The current time is 1 30p m 2 Set the turn off time with the TIMER control button PM 3 Point the signal window of the remote controller toward the indoor unit and press the RESERVE button The OFF mark starts lighting instead of flashing and the RESERVED sign lights A beep occurs and the TIMER lamp lights on the indoor unit PM Example The...

Page 13: ...ard and downward directions The horizontal air deflector is automatically set to the proper angle suitable for each operation The deflector can be swung up and down continuously and also set to the desired angle using the AUTO SWING button In Cooling operation do not keep the horizontal air deflector swinging for a long time Some dew may form on the horizontal air deflector and dew may drop CAUTIO...

Page 14: ...11 30 06 3 38 PM 16 17 ENGLISH 2 CLEANING OF 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 Wipe the water thoroughly If water remains at indicators or signal receiver of ind...

Page 15: ...e sleep timer takes priority During sleep timer operation the fan speed sets to LOW regardless of the preset speed The remote controller display indication will remain unchanged even with the LOW setting TIMER PROGRAMMING SLEEP TIMER OPERATION PROHIBITION 19 REGULAR INSPECTION PLEASE CHECK THE FOLLOWING POINTS EVERY EITHER HALF YEARLY OR YEARLY CONTACT YOUR SALES AGENT SHOULD YOU NEED ANY HELP 1 2...

Page 16: ...to power variations according to room temperature changes Mist is generated as the air within the room is suddenly cooled by conditioned air Water generated during defrosting operation evaporates and steam is emitted Caused as the smells and particles of smoke food cosmetics etc present in room air become attached the unit and blown off into the room again Defrosting is underway as the heating ope...

Page 17: ...ng plate Wireless remote controller Cabinet 11 280 60 5 47 50 22 60 60 190 400 70 70 190 Vertical air deflector Drain Drain hose Drain cap connection port When piping is drawn from the left side exchange the drain hose for the drain cap Narrow pipe 6 35 Wide pipe 9 52 About 370 About 108 About 70 Connecting cable 30 56 17 5 81 5 47 47 147 07K394_RAS 14EH2_015 018_E 2007 11 02 09 17 15 ...

Page 18: ...l Air outlet Handle Holes for anchor bolt 2 ø12 x 6 slots for ø8 0 bolt for 2 ø8 0 bolt Notch for anchor bolt Fixing hole Drain hole Drain hole OUTDOOR UNIT More than 50 More than 100 More than 200 More than 300 Rear side Service space 07K394_RAS 14EH2_015 018_E 2007 10 31 16 34 16 ...

Page 19: ...ON 32 7 90 9 34 7 94 5 OFF 32 0 89 6 35 3 95 5 M RED BLK WHT YEL BLU 35V 5V 0V 0 5V FG MODEL NAME RATING APPLICABLE MODELS REVERSING VALVE COIL 135 Ω 20 C RAC 14EH2 REACTOR L1 13 mH 0 224 Ω RAC 14EH2 REACTOR L2 25 5 mH 0 37 Ω RAC 14EH2 FILM CAPACITOR 45 µF RAC 14EH2 RAS 14EH2 POWER SOURCE DC 5V 35V DC 140 350V OUTPUT 25W 40W Control circuit built in BLU BLUE YEL YELLOW BRN BROWN WHT WHITE GRY GRAY...

Page 20: ... with the capillary tubes clogged or crushed or with too little refrigerant check the color of the refrigerating machine oil inside the compressor If the color has been changed conspicuously replace the compressor 2M 1 15 2M 1 40 U V W M M M WHITE YELLOW RED RAC 14EH2 ASC092CD A8JK 750W DC 220 350 V WHITE COMPRESSOR YELLOW RED FRONT SIDE OF OUTDOOR UNIT 07K394_RAS 14EH2_015 018_E 2007 10 31 16 34 ...

Page 21: ... 19 CAUTION The marked parts are very important ones for safety WIRING DIAGRAM MODEL RAS 14EH2 RAC 14EH2 A B L N 07K394_RAS 14EH2_019_A3_E 2007 11 02 09 48 19 ...

Page 22: ...RAS 14EH2 CIRCUIT DIAGRAM 20 07K394_RAS 14EH2_020 021_A2_E 2007 10 31 17 19 20 ...

Page 23: ... 21 RAC 14EH2 MODEL AX 8T11 SELF CHECK SELF MODE SERVICE SW PQ1 PQ2 PQ401 PQ402 PQ403 PQ404 PQ701 RED RED RED 07K394_RAS 14EH2_020 021_A2_E 2007 10 31 17 19 21 ...

Page 24: ...ircuit HARMONICS IMPROVEMENT CIRCUIT IPM Rotor magnetic pole position detection circuit lp ld ls Buzzer circuit Indicating lamp Indoor Outdoor interface circuit DC fan motor drive circuit Microcomputer clock circuit Indoor DC fan motor Overheat thermistor Defrost thermistor Outdoor temperature thermistor Indoor Outdoor interface circuit Reversing valve coil Power circuit Reset circuit Outdoor DC f...

Page 25: ... 23 button 25 26 26 27 28 26 RAS 14EH2 07K394_RAS 14EH2_023_A3_E 2007 10 31 16 45 23 ...

Page 26: ...TEC SHIFTW SHIFTC CLMXTP YNEOF TEION TEIOF SFTDSW DFTIM1 DFTIM2 RAS 14EH2 5200 min 1 5200 min 1 5050 min 1 3800 min 1 4800 min 1 4800 min 1 4300 min 1 4200 min 1 3400 min 1 2900 min 1 2500 min 1 2500 min 1 90 Seconds 80 60 2 00 C 1 33 C 30 00 C 25 00 C 5 00 C 9 00 C 1 00 C 43 Minutes 60 Minutes 07K394_RAS 14EH2_024_E 2007 10 31 16 43 24 ...

Page 27: ...or maximum speed CMAX will maintain for 60 minutes if indoor temperature is lower than CLMXTP No time constrain if indoor temperature is higher than CLMXTP 6 7 When fan is set to Med compressor speed will be limited to CJKMAX 8 When fan is set to Lo compressor speed will be limited to CBEMAX 9 During Cool Dashed when room temperature reaches set temperature 1 C compressor speed is actual speed x D...

Page 28: ... cleared 1 33 C 0 66 C Notes 1 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 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 4 The compressor is operated forcedly ...

Page 29: ...g Hot Dashed operation thermo off temperature is set temperature with shift value 3 C After thermo off operation continue in Fuzzy control mode 4 Compressor minimum ON time and OFF time is 3 minutes 5 During normal heating mode compressor maximum speed WMAX will maintain for 120 minutes if indoor temperature is higher than 18 C No time limit constrain if outdoor temperature is lower than 4 C 6 Dur...

Page 30: ...refresh defrosting cannot be engaged within 15 minutes after operation is started or defrosting is finished Sleep Lo Notes 1 The sleep operation starts when the sleep button is pressed 2 When the sleep button is set the maximum compressor speed is limited to WBEMAX and the indoor fan is set to sleep Lo 3 The indoor fan speed does not change even when the fan speed mode is changed Sleep Lo 4 When d...

Page 31: ...lve Single ended union Single ended union Single ended union Single ended union Charge port Charge port Service valve Service valve Service valve Service valve Silencer Electric Expansion valve Electric Expansion valve Reversing valve RAS 14EH2 RAC 14EH2 SUCTION TANK SUCTION TANK ...

Page 32: ...SCRIPTION OF MAIN CIRCUIT OPERATION MODEL RAS 14EH2 1 Reset Circuit The reset circuit initializes the microcomputer program when power is ON or OFF Low voltage at pin 7 resets the microcomputer and Hi activates the microcomputer When power ON 5V voltage rises and reaches 4 4V pin 1 of IC521 is set to Hi At this time the microcomputer starts operation When power OFF voltage drops and reaches 4 2V p...

Page 33: ...peration 2 Receiver Circuit IRR light receiver unit receives the infrared signal from the wireless remote controller The receiver amplifies and shapes the signal and outputs it 3 Buzzer Circuit When the buzzer sounds an approx 3 9kHz square signal is output from buzzer output pin T of the microcomputer After the amplitude of this signal has been set to 12Vp p by IC711 it is applied to the buzzer T...

Page 34: ...xcite to turn the rotor Table 4 1 shows the rotation angle of horizontal air deflectors Microcomputer 18 17 16 15 11 10 12 6 7 5 13 4 IC711 12V CN4 Rotor Auto sweep motor for horizontal air defectors Micro computer pins Step width 10ms Horizontal air deflectors 15 16 17 18 1 2 3 4 5 6 7 8 Fig 4 2 Microcomputer Output Signals Fig 4 1 Table 4 1 Auto sweep Motor Rotation Rotation angle per step Time ...

Page 35: ...he DC DC converter and the 35 V power supply from the outdoor unit to generate 12 V control power which drives the stepping motor during the operation In addition use the regulator IC 121 to generate 5 V power required for driving the micro computer and controlling fan motor If the terminal block was overheated due to a connecting cable improper connection the thermal fuse built in the terminal bl...

Page 36: ... the speed command voltage Fig 7 3 shows the relation between the voltage at the point B and the speed Some differences will occur due to the condition of the unit The fan motor outputs the feedback pulse of the speed which is input into the pin D on the micro computer This pulse is equivalent to a frequency of 12 60 speed Example 1000 min 1 x 12 60 200 Hz The micro computer monitors the frequency...

Page 37: ...al parts for the outdoor unit is composed of two P W B a power P W B and main P W B and a harmonics improvement circuit as shown in Fig 1 1 Main P W B This P W B is equipped with the rectification diode DC fan motor control circuit and the circuits around the micro computer which take various controls POWER P W B This P W B is equipped with the noise filter ICP power circuit interface circuit smoo...

Page 38: ... DB3 L1 C023 and L2 The DB3 L1 C023 and L2 shape waveform of the input current When the current runs through the L1 is taken for I1 and the current runs through the L2 is taken for I2 as shown in Fig 2 2 I1 becomes an input current to the capacitor which peak value was crushed by the L1 and I2 becomes a resonance current which causes the LC resonance using the L2 and C023 By combining the I1 and I...

Page 39: ...y absorb electrical noise generated during operation of compressor and also absorb external noise entering from power line to protect electronic parts Be sure to connect the earth cable between the indoor unit and the outdoor unit Otherwise the noise filter circuit won t operate properly 6 SA1 and VS1 to VS3 These surge absorber and varistors absorb external power surge such as induced thunder Be ...

Page 40: ...g a request signal The receiving circuit in the indoor unit consists of a comparator and transistor The interface signal from the outdoor unit on the DC 35V line is supplied to C821 where DC components are eliminated and is then shaped by the comparator The shaped signal is detected by diode amplified by amp and output to pin i of the indoor microcomputer Fig 3 2 shows the waveforms at each compon...

Page 41: ... 39 Fig 3 1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other Fig 3 1 Control P W B ...

Page 42: ... 0V 5V 0V 0V 35V Outdoor microcomputer Pin 11 Pin 68 Indoor microcomputer Pin 50 Pin 49 Fig 3 2 Voltages Waveforms of Indoor Outdoor Microcomputers Outdoor to Indoor Communications Fig 3 3 Voltages Waveforms of Indoor Outdoor Microcomputers Indoor to Outdoor Communications Outdoor microcomputer Pin 11 Pin 68 Indoor microcomputer Pin 50 Pin 49 ...

Page 43: ...ge is all 1s 3 Communications waveforms Leader 100ms Leader 100ms When reset approx 100ms When reset approx 10ms 35 V 34 V 36 V 0 7 0 7 7 7 0 33 3ms 3 2 1 No 0 Bit No 0 7 0 7 0 7 0 7 Bit No 0 3 2 1 33 3ms 33 3ms 33 3ms Transmit receive switching time 4 95ms 33 3ms 33 3ms Outdoor message Indoor message 33 3ms 33 3ms 0 Character No 2 Indoor microcomputer to outdoor microcomputer HIC ...

Page 44: ...is 1 Self diagnosis 0 LSB Outside temperature 0 LSB Compressor during operation Compressor command speed 0 LSB Compressor minimum rotation speed 0 LSB Compressor minimum rotation speed 1 Compressor minimum rotation speed 2 Compressor minimum rotation speed 3 Compressor minimum rotation speed 4 MSB Compressor command speed 1 Compressor command speed 2 Compressor command speed 3 Compressor command s...

Page 45: ...telligent power module and its peripheral circuit The three transistors on the positive E side are called the upper arm and the three transistors on the negative D side the lower arm Fig 4 1 Intelligent power module circuit U is ON V is ON IP limitter E E E ...

Page 46: ...essor is shown by formula below N 60 2 X 1 T Fig 4 3 shows voltage waveform at each point shown in Figs 4 1 and 4 4 First half of upper arm is chopper second half is ON and first half of lower arm is chopper second half is ON Fig 4 3 Voltage waveform at each point When power is supplied U V because of that U is chopped current flows as shown below 1 When U transistor is ON U transistor U coil V co...

Page 47: ...is ON Since current flows at point B only when U transistor and V transistor are ON the current waveform at point B becomes intermittent waveform as shown in Fig 4 3 Since current at point B is approximately proportional to the input current of the air conditioner input current is controlled by using DC current Id detection resistor Reference If power module is defected self diagnosis lamps on the...

Page 48: ...GBT in each phase to drive the IGBT When abnormal peak current was detected while the inverter is driving the IPM outputs the Fail signal immediately from the pin S and forces the lower arm transistor to shut off at the same time In this step the Q501 is turned on and the input signal of the upper arm is also shut off through the D501 and D502 so that all signals to the IGBT are shut off This sign...

Page 49: ...or P W B power supply for microcomputer peripheral circuits and IPM driver circuit and as well as DC 35V are produced by switching power circuit Switching power circuit performs voltage conversion effectively by switching transistor IC1 to convert DC 330V voltage to high frequency of about 20kHz to 200kHz ...

Page 50: ...is found in this step the power circuit has any failure Replace the power P W B A short circuited load may cause an output error not only in the load but also in the others Be sure to check all outputs of the loads Be sure to wait 15 minutes or more in order to discharge all the remaining voltage in the circuit to connect disconnect the wiring otherwise the components may be damaged The failures o...

Page 51: ...imiting the whole input of this room air conditioner system through the current sensor CT1 in order to keep the maximum rating of components by reading total operating current ID OVL is watching and limits the compressor current through the detection resistor which is built in IPM in order to control the compressor reliability Since the compressor reliability is related with its speed the ID OVL v...

Page 52: ...alue is determined by the amplification of the voltage amp circuit Amplification high DC current low Amplification low DC current high Fig 6 4 shows the rotation speed control When the voltage at pin t of the microcomputer exceeds the set value the microcomputer decreases the rotation speed of the compressor and reduces the load Fig 6 4 Fig 6 2 Fig 6 3 Judgment value according to rotation speed in...

Page 53: ... the start of the DC motor of the compressor RAC 14EH2 uses software to control the start current The start current varies when the supply voltage varies This control method copes with variations in the voltages as follows 1 Turns on the power module s U and V transistors so the current flows to the motor windings as shown in Fig 6 6 2 Varies the turn ON time of the U transistor according to the D...

Page 54: ...line voltages rise and 12V line voltage reaches 10 9V an reset voltage input to pin h of microcomputer is set to Hi Reset voltage will be hold Hi until the 12V line voltage drops to 9 90V even though the power shuts down Fig 6 7 Fig 6 8 MAIN P W B Microcomputer RESET OUT RESET 56 48 C204 0V R252 1 0V 8 2 3 IC5 1 2 5V D208 R287 C215 R284 R286 C225 R285 C226 R292 R289 R288 0V 0V 0V 0V 12V 12V line 1...

Page 55: ...ion the microcomputer transfers the defrosting condition command to the indoor microcomputer via the circuit interface The microcomputer always reads the outdoor temperature via a thermistor microcomputer pin x an transfers it to the indoor unit thus controlling the compressor rotation speed according to the value set at the EEPROM in the indoor unit and switching the operation status outdoor fan ...

Page 56: ...t 35V About 0 8V About 0 8V Collector voltage of Q701 MAX rotation speed instructed by indoor microcomputer after defrost is completed Table 8 1 8 Reversing valve control circuit Fig 8 1 Reversing valve control circuit will switch reversing valve ON OFF cooling ON according to instruction from indoor microcomputer depending on the operation condition shows in Table 8 1 Voltage at Q701 between Coll...

Page 57: ... expansion valve use the B 12 V output Use a 4 phase coil and feed power to the phases 1 and 2 then switch over the filed poles to control the opening of the valve The reference between conducting phase switch over direction and the open close direction are shown in Table 9 1 When the power is turned on approx 0 9 V is applied to the CN15 and the pins 1 to 4 and when no power is supplied 12 V is a...

Page 58: ...Fan motor will start to rotate when Vsp was proceeding over than 1 7V and generate FG pulse by rotation speed FG pulse will feed back to Outdoor microcomputer E DC Fan Motor circuit has to match the Fan Motor revolution with instructed revolution Such as FG feedback Faster Instruction Slower Decrease pulse width FG feedback Slower Instruction Faster Increase pulse width FG pulse is also used for F...

Page 59: ... growing inside of outdoor unit by snowing It may make Fan Lock Stop by strong wind ex 17m sec or above against the Fan rotation In this case unit will be restart again after a while In case of Fan Lock Stop even though the DC Fan Motor is rotating correctly the possible cause in Fan Motor problem or control board problem Stop after the Fan motor runs 2 minutes Fan Motor may be broken Caution Plea...

Page 60: ...m HIGH through MED to LOW while the temperature is preset at 30 Check if the indoor heat exchanger is frosted Wait for 3 4 minutes until it is defrosted If the air conditioner operates in cooling mode when it is cold the evaporator may get frosted It occurs during defrost ing Wait for 5 10 minutes until the condenser is defrosted At the beginning of heating the fan speed remains LOW for 30 seconds...

Page 61: ... before stopping operation At this point fan speed is automatic This is because Nice temperature reservation function is operating This function starts operation earlier so the preset temperature is reached at the preset time Operation may start maximum 60 minutes before the preset time It does not work It works only during cooling and heating This is because Nice temperature reservation function ...

Page 62: ...djust the temperature within a range of 3 C by pressing the Room Temperature button If the temperature is 1 C higher than the auto preset temperature 1 C will appear If the temperature is 1 C lower than the auto preset temperature 1 C will appear heard when operation is started When operation is started the compressor rotation speed goes to maximum to increase the heating or cooling capability so ...

Page 63: ...ply to the oscilloscope Remember that voltage of 175 V is applied to the 0V line on the P W B or the like as shown in the right diagram Indoor Controller Outdoor Controller Power Switch Point 400 F I P M Compressor motor Point line Control P W B Main P W B Voltage at point A Ground voltage Grounding 350V Point B 0V line Power inlet TROUBLE SHOOTING RAC 14EH2 PRECAUTIONS FOR CHECKING 07K394_RAS 14E...

Page 64: ...circuit part of the outdoor unit be sure to discharge the smoothing capacitors Discharge Procedure 1 Turn off the power of the indoor unit or pull out the power supply plug 2 After power is turned off wait for 10 minutes or more Then remove electrical parts cover and apply soldering iron of 30 to 75 W for 15 seconds or more to TAB3 GRAY and TAB4 RED terminals on the main P W B as shown in the figu...

Page 65: ... between the part and cabinet Removing electrical parts 1 Remove the electrical parts cover 2 Remove the connectors from the CN1 heat exchange thermistor CN4 stepping motor and CN10 fan motor 3 Remove two lock screws 4 Remove the electrical parts in the direction of arrow Removing control P W B 1 Remove the connectors from the CN2 and CN3 2 Remove the P W B from the P W B support INDICATING INDICA...

Page 66: ...remove the connector 3 When checking the voltage and waveform do not connect the probes to the forbidden areas show below Touching them may cause the ICP1 blowout and Q111 failure The Q111 is a MOS FET and its gate terminal is a high impedance When a probe such as a multimeter is contacted with the gate G the Q111 may have the continuous ON state to supply overcurrent in the circuit causing the IC...

Page 67: ...l times Note In some failure modes only the retry operation is repeated without lamp indication Failure modes that will repeat a retry operation without the indoor unit lamp indication are as follows OH thermistor temperature rise Outdoor unit communication error Power voltage abnormal Less frequent defects The LD301 indicates a mode of failure detected on the outdoor unit side by blinking frequen...

Page 68: ... 1 Room thermistor 2 Heat exchanger thermistor 1 Indoor fan locked 2 Indoor fan motor IC401 or IC402 abnormal Cautions 1 If the interface circuit is faulty when power is supplied the self diagnosis display will not be displayed 2 If the indoor unit does not operate at all check if the connecting cable is connected to the outdoor unit 3 To check operation again when the timer lamp is blinking you c...

Page 69: ... 67 IPM INTELLIGENT POWER MODULE SELF DIAGNOSIS LAMPS LD301 LD302 LD303 SERVICE SWITCH SELF DIAGNOSIS LIGHTING MODE MODEL RAC 14EH2 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 67 ...

Page 70: ...heck outdoor electrical parts Check the refrigerating cycle Normal No Yes Check the drive circuit IPM using the PRD checker Check the position sensor circuit With the unit set in the operating state press the start stop button Does the unit operate for approximately 2 seconds the LD303 coming on and then stop due to a failure of switching the lamp blinking 4 times OUTDOOR UNIT 07K394_RAS 14EH2_061...

Page 71: ...able connected incorrectly inserted incompletely or disconnected Not running Running Open the outdoor unit and observe the self diagnosis lamp LD301 Count how many times the lamp blinks Blinks other than 1 time Blinks 1 time Can the unit be operated using the outdoor unit service switch See the nameplate on the outdoor unit for operating instructions Check the outdoor electrical parts Check the in...

Page 72: ...on cable and correct any defective section wrong connection incomplete insertion Is AC220 230V being generated between terminals A and B on the outdoor unit terminal board Is DC35V or 20V being generated between terminals C and D on the indoor unit terminal board Is the microcomputer reset input pin 7 Hi Is the microcomputer clock signal 10MHz at pins and A being generated normally Is DC35V is bei...

Page 73: ... operation check 3 Air deflector does not move others are normal Are pulse signals output at microcomputer pins E H when auto swing is turned on in the fan mode Replace the microcomputer Is a voltage over 15 or below 10V being generated on the 12V line Replace IC111 Yes Yes Yes Yes No No No No Check IC711 If it is normal replace the air deflector motor Perform final operation check 07K394_RAS 14EH...

Page 74: ...nnection cable securely Replace IC121 Check if a short occurs in the 5V line If the 5V line is shorted ICP1 will be open again Check to see if the connection cables are disconnected or reversed If normal check the outdoor unit P W B Has the terminal board thermal fuse blown open Replace Q111 and IC111 Is DC5V being generated Perform final operation check 1 When the unit is not in operation the vol...

Page 75: ...ld flash in orange when you operate the remote control unit if it is good Ultra redray test card Sensible area Within 2 cm Check functions again If it does not work replace the remote controller Buzz Within 15 cm AM radio Check the LED D1 with a multimeter Replace the battery Install the battery in the correct polarity Yes Yes No No No Yes Does the radio buzz noisily Is battery polarity correct Is...

Page 76: ... Be sure that the power switch is turned off or the power cable is disconnected before servicing Removing the P W B s System Configuration of Outdoor Unit Electrical Parts The outdoor unit electrical parts consist of two P W B as shown in the figure Main P W B M board Contains a rectifier circuit and inverter module their controlling microcomputer and microcomputer peripheral control circuits The ...

Page 77: ...to improve power factor To replace the capacitor remove the power P W B and then 1 Remove two screws fastening the capacitor seat 2 Slide the capacitor seat in the direction of the arrow Sliding Direction 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 75 ...

Page 78: ...ce defective parts Is the power circuit normal See the description on power circuit for details Is the switching power circuit OK Has the 3A fuse blown Check to see if C and D cables are connected correctly If reversed or incompletely inserted correct the cable connection Replace any defective parts If the 3A fuse has blown the varistor 2 etc may also be defective With the piping and lines A B C D...

Page 79: ...ing An error occurs after the fan operates for 2 minutes Is the voltage between 4 and 6 at CN24 normal Normally the voltage is above approx DC1 7V Connect the connector Remove any obstructions Replace the fan motor and main P W B Is the voltage between 4 and 7 at CN24 normal Check to see if the voltage is within 2 5V 0 5V using a tester In effect the output voltage is alternately switched between ...

Page 80: ...ly AC220 230V Check the interior wiring Are TAB 1 TAB 2 TAB 3 TAB 4 TAB 5 TAB 6 TAB 11 TAB 12 reactor and C023 yellow green connected properly Connect properly Replace the power P W B Possible causes include Power relay malfunction Defective microcomputer terminal Yes Yes Yes No No No 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 78 ...

Page 81: ...terminals C and D Normal DC32V 39V Standby DC18V 23V Is DC35V being output at both ends of R35 Connect CN 3 and CN4 Connect properly Replace the power P W B Defective SW power supply Replace the power P W B NF coils IF coils etc may be broken Check the interface circuit and replace the main P W B if needed Yes Yes Yes Yes Yes No No No No No 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 79 ...

Page 82: ...r servicing Is the continuity of the thermistor normal Is the thermistor circuit normal Connect the thermistor Replace the thermistor Replace parts in the thermistor circuit Check continuity of pattern and lead wires according to the P W B and schematic diagrams Yes Yes Yes No No No No 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 80 ...

Page 83: ... unit for defective shielding LD301 blinks 4 times Failure of switching Is the 15V power supply output normal Power P W B display Is the intelligent power module IPM normal Inverter section The intelligent power module may be defective Replace the main P W B See System Power Module Diagnosis With CN3 and CN4 disconnected is the 15V output between 15V and 15 0V on the power P W B Replace the power ...

Page 84: ...time Reset stop However the unit always resets and stops just after power is supplied this does not indicate a fault Is the reset circuit normal Normally pin 7 of CN18 is approx 5V Replace the main P W B Make sure again that connectors are connected securely Perform final operation check Yes Yes Yes No No 07K394_RAS 14EH2_061 082_E 2007 10 31 16 46 82 ...

Page 85: ... refrigerant If the compressor checker for an inverter type air conditioner is available re check using it JUDGING BETWEEN GAS LEAKAGE AND COMPRESSOR DEFECTIVE Blinking off Time until the lamp lights Approx 10 seconds Approx 10 seconds Approx 10 seconds Within Approx 30 seconds Compressor Compressor Gas leakage Possible malfunctioning part LD301 Self diagnosis lamp Lighting mode Blinks 2 times Bli...

Page 86: ...o push the service switch for a second again to stop the forced cool operation HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY 1 Connect the large dia pipe side and small dia pipe side service valve using a pipe Parts to be prepared 1 Reducing union 2 8 6 35 mm 3 8 9 52 mm 2 Copper pipe 2 8 and 3 8 Connect the small diameter service value and the large diameter service valve using the reducing union...

Page 87: ...vice Circuit diagram of the module Terminals symbol mark of the module See next page for measuring value using multimeter Collector Emitter RASF IPM Intelligent Power Module DIAGNOSIS 07K394_RAS 14EH2_083 092_E 2007 10 31 16 46 85 ...

Page 88: ...de note Sometimes it may misjudge as OK because of low conductivity when power module was damaged as disconnect mode In this case please check the resistance by reversing the probe polarity and consider OK when it was low resistance Also it is OK if the resistance was as same as the other phases U V W Driver circuit internal IC 15V will not be generated when the internal IC has malfunctioned To fi...

Page 89: ...rward and release the claws 2 Hold the front cover at both lower sides and pull them forward to remove Fig 3 3 Control P W B and Indicating P W B 1 Remove each connector from the lead wire 2 Remove the four P W B supports from the control P W B 3 Pull the support hook at the upper side of the indication lamp of the indicating P W B and pull out the P W B forward Fig 4 Procedure for Disassembly and...

Page 90: ...1 Electrical parts 1 Remove the service value cover lock screws and lower the cover to remove it 2 Remove the top cover lock screw and raise the cover to remove it Fig 8 3 Remove the front cover lock screw 4 Lower the right side of the front cover and pull it forward Then remove the cover from the hook 5 Pull the right side of the front cover a little and pull up the left side to remove it from th...

Page 91: ...13 9 17 38 18 14 12 11 10 23 20 15 16 37 36 35 34 33 41 40 32 19 22 43 21 29 30 25 31 24 26 42 28 27 7 6 2 3 4 8 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAS 14EH2 07K394_RAS 14EH2_083 092_E 2007 10 31 16 46 89 ...

Page 92: ... 90 07K394_RAS 14EH2_083 092_E 2007 11 12 09 12 90 ...

Page 93: ...7 42 43 45 31 41 38 36 37 35 39 34 32 32 40 25 26 27 28 29 5 33 51 21 19 23 24 22 1 49 48 50 20 17 18 52 4 3 2 15 12 16 10 11 13 6 8 14 7 9 OUTDOOR UNIT MODEL RAC 14EH2 07K394_RAS 14EH2_083 092_E 2007 10 31 16 46 91 ...

Page 94: ... 92 07K394_RAS 14EH2_083 092_E 2007 11 12 09 12 92 ...

Page 95: ...HITACHI AW NO 0029E RAS 14EH2 RAC 14EH2 07K394_RAS 14EH2_000cover_E 2007 10 31 17 14 3 ...

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