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Hitachi RAM-68NP3B Service Manual Download Page 66

7 times

076

01

Narror pipe thermistor 

abnormal 

(Indoor no.2)

7 times

077

01

Wide pipe thermistor 

abnormal 

(Indoor no.2)

7 times

078

01

Narror pipe thermistor 

abnormal 

(Indoor no.3)

7 times

079

01

Wide pipe thermistor 

abnormal 

(Indoor no.3)

Thermistor's connector not connected 

or thermistor's wire worn out or 

shorted.

1. Thermistor

2. Connection of thermistor faulty

3. Thermistor circuit

Summary of Contents for RAM-68NP3B

Page 1: ...AND DIMENSIONAL DIAGRAM 18 MAIN PARTS COMPONENT 19 WIRING DIAGRAM 21 CIRCUIT DIAGRAM 23 BLOCK DIAGRAM 25 BASIC MODE 27 REFRIGERATING CYCLE DIAGRAM 47 DESCRIPTION OF MAIN CIRCUIT OPERATION 48 TROUBLE SHOOTING 82 PARTS LIST AND DIAGRAM 90 After installation 850 800 298 55 W A COOLING CAPACITY DC INVERTER TRIPLE SYSTEM MULTI TYPE MODEL POWER SOURCE TOTAL INPUT TOTAL AMPERES SPECIFICATIONS OUTDOOR UNI...

Page 2: ...r 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 ins...

Page 3: ...oring of parts Even rejected goods should be handled in the same way Fig 1 Conductive container 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 1M earth resistance through a ring or bracelet 3 Be careful not to touch the parts with your clothing when you hold a part even if a bod...

Page 4: ...the screwed part using a rag plate Soldering iron Grounding wire Fig 4 Grounding a solder iron Use a high insulation mode 100V 10M or higher when ordinary iron is to be used 7 In checking circuits for maintenance inspection or some others be careful not to have the test probes of the measuring instrument short circuit a load circuit or the like Metal plate of aluminium stainless steel etc Staple ...

Page 5: ... or missoperation and re start in a moment there is occasion that the cooling 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 coolin...

Page 6: ...WITCH SERVICE SWITCH TRANSFORMER VARISTOR NOISE SUPPRESSOR THERMOSTAT REMOTE CONTROL SWITCH LIQUID CRYSTAL 47 W NO NO JU151XC1 NO YES YES 5 0A G4A NO NO YES NO 450NR YES YES IC NO 2300g UNIT REFRIGERANT CHARGING VOLUME Refrigerant R410A WITHOUT REFRIGERANT BECAUSE COUPLING IS FLARE TYPE PIPES MAX In case the pipe length is more than 30m add refrigerant R410 at 20gram per every meter exceeds RAM 68...

Page 7: ...U h TOTAL INPUT W EER B T U hW TOTAL AMPERES A POWER FACTOR MAXIMUM LENGTH OF PIPING STANDARD RAM 68NP3B 1ø 220 240V 50 60Hz 20A 6 80 23 200 2 080 11 15 9 55 8 75 99 8 50 29 010 2 280 12 72 10 5 9 6 99 MAX 60m THREE UNIT TOTAL CE EMC LVD RAM 68NP3B MODEL W PACKING mm H D cu ft 1 008 848 394 11 89 63 GROSS WEIGHT kg 6 35DX4 9 52DX3 FLARE NUT SIZE SMALL LARGE INDOOR SUCTION TEMPERATURE C COOLING OPE...

Page 8: ...UNIT OPERATION WHEN THREE INDOOR UNITS ARE CONNECTED Total nominal cooling capacity should not be more than 11kW ONE UNIT 9 6 3 73 A 2 20 8 00 2 40 9 50 3 27 A 10 5 10 0 2 20 8 00 2 40 9 50 8 75 10 0 10 5 6 80 9 55 9 13 9 6 3 73 A 3 27 A 10 5 A 2 20 8 00 2 40 9 50 11 0 6 80 9 55 9 13 8 75 10 1 9 6 3 71 8 8 3 27 A 10 5 9 5 6 80 9 6 9 1 2 20 8 00 2 40 9 50 9 6 3 73 A 3 27 A 10 5 10 0 A 2 20 8 00 2 4...

Page 9: ... 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 11 0kW Be sure to connect two or three indoor units to this outdoor unit If not condensed water may drop resulting in trouble ...

Page 10: ... 5 0 6 10 11 16 15 23 1 8 2 5 3 5 8 12 9 15 14 21 1 8 2 5 5 0 7 11 8 13 17 25 1 8 1 8 5 0 7 11 7 11 18 27 1 8 2 5 2 5 8 12 11 17 11 17 1 8 1 8 2 5 8 12 8 12 11 17 1 8 1 8 3 5 8 12 8 12 15 23 1 5 3 5 5 0 6 9 16 24 16 24 1 8 1 8 1 8 8 12 8 12 8 12 1 5 2 5 5 0 6 10 8 13 18 26 1 5 3 5 3 5 6 10 12 19 12 19 1 5 2 5 2 5 8 12 11 17 11 17 1 5 2 5 3 5 7 11 11 16 14 22 1 5 1 8 3 5 8 12 8 12 16 24 1 5 1 8 5 0...

Page 11: ... 11 ...

Page 12: ... 12 ...

Page 13: ... 13 ...

Page 14: ... 14 ...

Page 15: ... 15 three ...

Page 16: ... unit Optional flare adaptor for piping is necessary One unit of 1 5kW 1 8kW 2 5kW 3 5kW or 5 0kW 5kW unit Optional flare adaptor for piping is necessary One unit of 1 5kW 1 8kW 2 5kW 3 5kW or 5 0kW 5kW unit Optional flare adaptor for piping is necessary ...

Page 17: ... 17 ...

Page 18: ... 19 1 2 3 1 2 3 1 2 3 RAM 68NP3B ...

Page 19: ... 19 RAM 68NP3B ...

Page 20: ... 20 9 a 0 RAM 68NP3B ...

Page 21: ... 21 RAM 68NP3B ...

Page 22: ...WIRING DIAGRAM MODEL RAM 68NP3B COLOR LEGEND RED RED WHT WHITE BLK BLACK BLU BLUE YEL YELLOW BRN BROWN GRN GREEN 21 ...

Page 23: ... C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 100 100 100 A M 5 1 6 A M 5 1 6 1K R471 R472 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 C 5 1 16 HIC2 R501 R502 R503 R504 R505 R506 R507 510K 1K 100 5 1K 5 1K 390 390 R522 R523 R524 R525 R526 R527 R528 R529 R530 390 390 390 390 390 390 10K 10K 10K HIC C 5 1 16 HIC C 5 1 16 ...

Page 24: ... Power relay inrush protection circuit Main power circuit Communication circuit between micro computer Reset circuit Inverter power circuit Indoor outdoor interface circuit 1 Indoor outdoor interface circuit 2 Indoor outdoor interface circuit 3 Communication selection circuit 1 Communication selection circuit 2 Electric expansion valve 2 Electric expansion valve 3 Wide pipe 1 Narrow pipe 2 Wide pi...

Page 25: ...RAM 68NP3B PRINTED WIRING BOARD LOCATION DIAGRAM Main board component side ...

Page 26: ...Main board solder side RAM 68NP3B ...

Page 27: ...Inverter board component side RAM 68NP3B ...

Page 28: ...Inverter board solder side RAM 68NP3B ...

Page 29: ... Main HIC board bottom side Main HIC board top side Inverter HIC board top side Inverter HIC board bottom side RAM 68NP3B ...

Page 30: ... 33 ...

Page 31: ... 35 REFERENCE RAM 68NP3B ...

Page 32: ...teady speed period but it starts fuzzy control 3 The thermo OFF temperature during cool dash is cooling set temperature including cooling shift 3 C After thermo OFF cool dash is finished and fuzzy control starts 4 The compressor minimum ON time and minimum OFF time is 3 minutes 5 The time limit for which the maximum compressor speed CMAX_M or CMAX2_M during normal cooling can be maintained is less...

Page 33: ... 39 ...

Page 34: ... 41 ...

Page 35: ... 43 SFTDSW_M OFTMPW_M ...

Page 36: ... 45 ...

Page 37: ...ess than 40 C steady speed period is fi nished the TD control is entered The start openings are set to PSTARTC K_d The start openings are held during the steady speed period when the compressor is started After the 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 f...

Page 38: ...alancing period Electric expansion valve period until defrost MAX speed DEFMAX is reached Balancing period for TDF415_ U sec TSKTM2 sec Accelera ng by DFSTEP min 1 for dura on TDFSPT sec in remaining reverse cycle Defrost inhibit period linked to outdoor temperature has elapsed condition ASTUS 0 Released by condition during balancing period When remaining balancing period has elapsed returned to i...

Page 39: ... 48 RAM 68NP3B ...

Page 40: ... 49 RAM 68NP3B ...

Page 41: ... 50 RAM 68NP3B ...

Page 42: ... 51 RAM 68NP3B ...

Page 43: ... 52 ...

Page 44: ...RAM 68NP3B ...

Page 45: ...ocomputer and peripheral circuits B 12V Operating power supply for electric expansion valve 16V Power supply for compressor motor drive IPM and fan motor drive IPM 12V Power supply for reversing valve relay power relay in rush current relay and operating amplifier for compressor motor and fan motor current amplification 5V Power supply for inverter microcomputer and peripheral circuits Primary Compo...

Page 46: ...or Output Failures for Reference Tester terminal 16V indicator J9 Tester terminal 0V indicator C891 Tester terminal 12V indicator WH65 2 Tester terminal 0V indicator C891 Tester terminal 5V indicator R814 Tester terminal 0V indicator C891 Tester terminal B 5V indicator J4 Tester terminal B 0V indicator J5 Tester terminal B 12V indicator R120 Tester terminal B 0V indicator J5 Tester terminal B 15V ...

Page 47: ...ge DB601 DB602 DC voltage is not generated and operation might not occur Reference In case of IPM failure or poor connection immediately after starting the compressor it might stop due to abnormal speed reduction switching failure Ip cut etc Diode bridge DB601 DB602 Rectifies AC220 240V from terminal blocks L and N to a DC power supply Intelligent Power Module IPM used for configuration of inverter ...

Page 48: ...CT Ip cut Input voltage Vd 4 IGBT for improving power factor Q601 Q602 When load on the compressor increases the power factor is improved by applying current to the chopper interval between Q601 and Q602 shown in Fig 2 3 Fig 2 3 DC260 360V Vd DC Q601 Q602 Chopper interval Current flowing through reactor during high load Q601 Q602 Chopper interval Current flowing through reactor during low load Effect...

Page 49: ...checks only if the result of this check is normal If this check produces an abnormal result either a lead wire is broken or there is a failure in the reversing valve Voltage at each point is approximately as shown below table when measure by tester When voltage between pin 1 to pin 4 of CN2 is measured 3 Reversing Valve Control Circuit The reversing valve is controlled by operation commands from t...

Page 50: ... 59 ...

Page 51: ...istance value for DEF thermistor grows large and the voltage of pin on the microcomputer falls If this voltage drops below the value set and stored internally defrosting of the main microcomputer will start Outdoor temperature is read by the outdoor temperature thermistor voltage of pin on the microcomputer Commands from the indoor microcomputer values read from the outdoor temperature thermistor ...

Page 52: ...y 0 9V or 12V there is an abnormality in that expansion valve or the main microcomputer The logic waveform for when an expansion valve operates is shown in Fig 5 2 Fig 5 1 CLK CLK C421 7 IC32 8 G Q A SER Q G 6 5 SCK 4 3 2 12 11 15 14 13 VDD Q B 1 16 9 Q C Q D Q E Q F Q H GND Q H XA 6P 4 2 3 5 6 BLU C423 B 12V CN26 1 SCLR RCK 10 B 0V B 0V 1 16 15 5 12 13 3 4 10 8 7 6 11 14 2 B 5V IC34 9 B 0V B 0V C...

Page 53: ...or the 16th cycle of the clock signal the latch signal from pin on the microcomputer is turned OFF Lo level 500µs and then ON again Hi level After the time required to apply current has elapsed if powering of the expansion valve is required the cycle returns to and repeats the operation With the operation described above the opening of expansion valves is controlled while applying current to phase...

Page 54: ... 63 ...

Page 55: ... 64 ...

Page 56: ... 65 ...

Page 57: ...2 Ｒ309 Ｒ342 Ｒ310 Ｒ311 Ｒ331 Ｒ332 Ｑ332 Ｃ341 Ｔ301 0Ｖ 12Ｖ 0Ｖ Ｑ331 88 52 51 Outdoor transmitting circuit for Indoor 1 Approx 450µs Approx 750µs Microcomputer transmission signal Microcomputer reception signal Outdoor side Outdoor unit reception input 1 Outdoor unit transmission output 1 Outdoor unit reception input 2 Outdoor unit transmission output 2 Communication switching circuit Outdoor switching 2...

Page 58: ...and Q102 will be OFF and causing 16V also drop to 0V Fig 8 1 Main Microcomputer Standby output Unit will enter hibernation mode during below stanby condition if not received any signal from remote controller and expansion valve already completed initialization For inspection during hibernation mode service person can measure DC voltage B 15V B 12V and B 5V on Main P W B But to measure DC voltage 1...

Page 59: ... 68 ...

Page 60: ...cuit and open circuit of the IPM to determine IPM condition either in good condition or already broken 5 Self check diagnosis result will appear The content of diagnosis result shall refer to below table Self check diagnosis result In case abnormality found at the checking result please confirm the connecting cord having problem or not before replace the defect part according to the table of self ...

Page 61: ...ly The test switch is accepted only once after power ON After operation by remote controller it is not accepted 4 When the operation with the test switch is done turn OFF the breaker 1 Turn OFF the breaker and wait for 1 minute or more before turn ON back the breaker 2 Detach the electrical cover of outdoor unit and ensure LD353 is blinking once 3 Wait 20 seconds or more before pressing the test s...

Page 62: ... 71 ...

Page 63: ...Lighting mode of the self diagnosis lamp Lighting mode of the self diagnosis lamp 2 ...

Page 64: ... 73 ...

Page 65: ...essor 3 OH thermistor circuit 4 Fan motor 5 Fan motor circuit 8 times 008 01 Communication error between microcomputer Communication between inverter microcomputer and main microcomputer failed 1 Connector insertion at CN21 CN22 2 Main and Inverter P W B 9 times 009 01 Indoor type mismatch Single model connected 1 Main P W B 2 Indoor unit 10 times 010 01 Abnormal power source Power supply voltage ...

Page 66: ...mistor abnormal Indoor no 2 7 times 078 01 Narror pipe thermistor abnormal Indoor no 3 7 times 079 01 Wide pipe thermistor abnormal Indoor no 3 Thermistor s connector not connected or thermistor s wire worn out or shorted 1 Thermistor 2 Connection of thermistor faulty 3 Thermistor circuit ...

Page 67: ...ain PWB Main power supply circuit is abnormal Abnormal Yes Please replace Main PWB and reversing valve coil Valve or valve driver circuit is abnormal LD353 not blink Main power supply circuit is normal Is the breaker operated normally Abnormal Please check indoor electrical Consider as communication error Yes Yes Yes Unit is entering Hibernation Mode during stanby All LED is OFF Normal Yes Yes No ...

Page 68: ...rmal Is DEF thermistor wire worn out or short circuit Yes Abnormal Yes Yes Yes Yes No No No No No Are CN21 CN22 connectors inserted properly Yes Normal Please check refrigerant cycle Assuming refrigerant leak occurs No Normal Abnormal Abnormal Abnormal Abnormal Normal If not recovered after check the cycle please replace the Main PWB Thermistor detection circuit abnormal Secure the insertion of CN...

Page 69: ...ectrical cover on how to check the DC voltage Are CN23 CN25 connectors connected properly Yes Yes Yes No No No Yes No Cooling Outdoor condenser covered with dust or something block it Heating Indoor unit evap or filter covered with dust LD352 3 times blink LD351 Lit Outdoor thermistor abnormal LD352 4 9 times blink LD351 Lit Exp valve thermistor abnormal Please replace outdoor thermistor Please rep...

Page 70: ...ven circuit is abnormal Check if something block the fan movement and confirm the fan motor itself is not damage Remove the blocking object If the fan is abnormal please replace it Normal Normal Check fan motor connector Yes Is F4 2A fuse blown Please secure connection OD fan motor is normal Please replace the Inverter PWB Fan motor driven circuit is abnormal Please replace outdoor fan motor and In...

Page 71: ...ew minutes to restart Outdoor electrical and outdoor fan motor is OK After unit is restart Stop Check outdoor fan motor Detail shall refer to outdoor fan motor page or refer to label on the electrical cover Any abnormality found at the fan motor Fan motor Abnormal Please replace outdoor fan motor Connecting cable repair and replace the fuse Is the indoor unit timer lamp show 12 times blinking Rech...

Page 72: ...ectors 4 places and TAB terminal 4 places 1 Electrical parts preparation to remove board 1 Remove screw that fix the service valve cover and push it down to take it out 2 Remove the screws on both sides of top cover and then remove the top cover 3 Remove the screws that holding the electrical cover and then remove the cover SCREW Hook 2 places CN24 CN25 Compressor connector Power relay TAB black T...

Page 73: ...he board into the pcb support and fix it with hooks 2 places 2 Release the hooks 2 places that locking the board and lift up the board to take it out 3 Dismantle procedure of main board 1 Un insert connector 13 places TAB terminal 7 places and un screw 1 piece earth screw Hook 2 places Earth wire fix screw CN12 CN19 CN15 CN10 CN9 CN8 CN11 CN21 CN23 CN2 Power relay TAB4 red TAB5 black Terminal Bloc...

Page 74: ...and lock it with hook 2 places 2 Insert back the connectors 13 places TAB terminals 7 places and 1 piece of earth screw Arrange hole position 7 places 基板を挿入 Board insert direction Board insert direction CN24 CN25 Compressor connector Power relay TAB black TAB2 yellow TAB1 brown TAB4 red CN22 Hook 2 places Earth wire fix screw CN12 CN19 CN15 CN10 CN9 CN8 CN11 CN21 CN23 CN2 Power relay TAB4 red TAB5...

Page 75: ... 84 ...

Page 76: ... 85 MODEL RAM 68NP3B ...

Page 77: ...26 42 1 3 30 40 12 28 27 13 5 2 6 9 37 35 23 36 29 15 10 21 11 8 34 33 32 17 24 18 19 20 38 39 41 14 7 16 25 ...

Page 78: ...M 68NP3B 1 P W B INVERTER PMRAM 68NP3B 1 EXPANSION VALVE COIL BC PMRAM 68NP3B 1 COMPRESSOR PMRAM 68NP3B 1 P W B MAIN PMRAM 65QH4 1 STRAINER CO PIPE AS 1 PMRAM 68NP3A 1 CABINET PMRAM 65QH4 1 THERMISTOR OUTSIDE TEMPERATURE PMRAM 53NP2B 1 EXPANSION VALVE COIL R PMRAM 53NP2B 1 FAN MOTOR PMRAM 53NP2B 4 EXPANSION VALVE PMRAM 53NP2B 1 EXPANSION VALVE COIL W PMRAM 33NP2B 1 COIL REVERSING VALVE PMRAM 33NP2...

Page 79: ...HITACHI PM NO 0585E Printed in Malaysia RAM 68NP3B ...

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