LG A2UW18GFA0 Service Manual Download Page 95

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Part 5. Trouble Shooting

- 94 -

LGE Internal Use Only

Display

code

Title

Cause of error

Check point & Normal condition

D-pipe sensor (Inverter)

• Open / Short
• Soldered poorly
• Internal circuit error

1. Bad connection of thermistor connector
2. Defect of thermistor connector (Open/Short)
3. Defect of outdoor PCB

Air sensor

• Open / Short
• Soldered poorly
• Internal circuit error

1. Bad connection of thermistor connector
2. Defect of thermistor connector (Open/Short)
3. Defect of outdoor PCB

Condenser Mid-pipesen-
sor

• Open / Short
• Soldered poorly
• Internal circuit error

1. Bad connection of thermistor connector
2. Defect of thermistor connector (Open/Short)
3. Defect of outdoor PCB

Suction Pipe sensor

• Open / Short
• Soldered poorly
• Internal circuit error

1. Bad connection of thermistor connector
2. Defect of thermistor connector (Open/Short)
3. Defect of outdoor PCB

Condenser Out-pipe sen-
sor

• Open / Short
• Soldered poorly
• Internal circuit error

1. Bad connection of thermistor connector
2. Defect of thermistor connector (Open/Short)
3. Defect of outdoor PCB

Check Point

1. Estimate the resistance of each sensor.(Unplugged)

2. Check the value of the resistor of thermistor.

D-pipe sensor (Inverter)

: Normal Value of the resistor is 200kΩ at 25℃

Air sensor

: Normal Value of the resistor is 10kΩ at 25℃

Cond. Mid-pipe sensor

: Normal Value of the resistor is 5kΩ at 25℃

Suction pipe sensor

: Normal Value of the resistor is 5kΩ at 25℃

Condenser Out-pipe sensor

: Normal Value of the resistor is 5kΩ at 25℃

Is sensor connected

to PCB correctly??

Is sensor value correct?*

Connect sensor to PCB correctly

Replace sensor

Replace corresponding
outdoor unit PCB

Yes

■

Error Diagnosis and Countermeasure Flow Chart

Summary of Contents for A2UW18GFA0

Page 1: ...itioner SVC MANUAL General MODEL Multi Inverter Type CAUTION Before Servicing the unit read the safety precautions in General SVC manual Only for authorized service personnel Internal Use Only http biz lgservice com ...

Page 2: ...n Functions 17 5 Reliability 18 6 Convenience Functions Controls 19 7 Special Function KIT 26 Part 3 Basic Control 29 1 Normal operation 30 2 Compressor control 30 3 EEV Electronic Expansion Valve control 30 4 Oil return control 31 5 Defrost control 31 6 Protection control 32 Part 4 Test Run 33 1 Check before Test Run 34 2 Test Run Flow chart 35 3 Test Runing 36 Part 5 Trouble Shooting Guide 38 1 ...

Page 3: ... 2 Copyright 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only 1 Safety Precautions 3 2 Model Line Up 6 3 Nomenclature 9 Part 1 General Information ...

Page 4: ...t is connected to the power cables This volt age is extremely dangerous and may cause death or severe injury if come in con tact with it Do not touch the discharging refrigerant gas during the repair work The discharging refrigerant gas The refrigerant gas can cause frostbite Release the refrigerant gas completely at a well ventilated place first Otherwise when the pipe is disconnected refrigerant...

Page 5: ...before connect or disconnect connector or parts damage may be occurred Do not use a defective or underrated circuit breaker Use the correctly rated breaker and fuse Otherwise there is a risk of fire or electric shock Install the panel and the cover of control box securely Otherwise there is risk of fire or electric shock due to dust water etc Indoor outdoor wiring connections must be secured tight...

Page 6: ...rge section and the non charge metal section Earth position If the resistance value is low a disaster such as a leak or electric shock is caused at user s side Check the drainage of the indoor unit after the repair If drainage is faulty the water to enter the room and wet floor Check to see if the power cable plug is not dirty or loose If the plug is dust or loose it can cause an electrical shock ...

Page 7: ...AMNW09GDBL1 LMN097HVT AMNW12GDBL1 LMN127HVT AMNW15GDBL1 LMN157HVT SC AMNW18GDCL1 LMN187HVT AMNW24GDCL1 LMN247HVT ART COOL Mirror SB AMNW09GDBR1 LMAN097HVT AMNW12GDBR1 LMAN127HVT SC AMNW18GDCR1 LMAN187HVT ART COOL Gallery SF AMNW09GAF11 LMAN097HVP AMNW12GAF11 LMAN127HVP Ceiling cassette 4 way TR AMNW07GTRA0 LMCN077HV AMNW09GTRA0 LMCN097HV AMNW12GTRA0 LMCN125HV TQ AMNW18GTQA0 LMCN185HV Ceiling conce...

Page 8: ...ribution type Model Name A2UW18GFA0 LMU18CHV A3UW24GFA0 LMU24CHV A4UW36GFA0 LMU36CHV No of connectable indoor units Min Max 2 2 2 3 2 4 Total capacity index of connectable indoor units 24 33 48 Power supply 208 230V 1Ø 60Hz Chassis Model Name A8UW54GFA0 LMU540HV No of connectable indoor units Min Max 2 8 Total capacity index of connectable indoor units 73 Power supply 208 230V 1Ø 60Hz Chassis ...

Page 9: ...es Branch Type No of BD Units Accessory Model Name Applicable Model Specifications Gas Liquid Y Branch 2 PMBL5620 MULTIFMAX To BD unit Ø19 05 3 4 Ø19 05 3 4 To ODU Ø19 05 3 4 To BD unit Ø9 52 3 8 Ø9 52 3 8 To ODU Ø9 52 3 8 No of connectable indoor units Min Max 1 2 1 3 1 4 Model name PMBD3620 PMBD3630 PMBD3640 PMBD3641 Connectable indoor unit capacity kBtu h 9 24 9 24 9 24 9 36 BD unit ...

Page 10: ...80 415V 50 60Hz Chassis naem Only Multi Indoor unit type Only Multi A ART COOL Gallery D Wall Mounted ART COOL Mirror T Ceiling cassette B Ceiling concealed duct N Vertical AHU Function A Basic L Plasma Wall mounted C Plasma ceiling cassette Front panel design color of ART COOL type R Mirror 1 Gallery Indicates that this is multi system outdoor unit using R410A Ex A4U Connectable max 4 indoor unit...

Page 11: ...for training and service purposes LGE Internal Use Only P M BD 36 2 0 Serial number Number of connectable indoor units Max capacity of connectable indoor units 36 mean that 5k 24k Indoor unit connected to BD unit BD Branch distributor M Multi system outdoor unit P Parts 3 3 BD units Global ...

Page 12: ...ns 17 4 1 E S P External Static Pressure Setting 17 5 Reliability 18 5 1 Hot start 18 5 2 Self diagnosis Function 18 5 3 Soft dry operation 18 6 Convenience Functions Controls 19 6 1 Cooling heating Operations 19 6 2 Auto cleaning operation 20 6 3 Auto Operation Artificial Intelligence 20 6 4 Auto restart Opeartion 21 6 5 Child Lock Function 22 6 6 Forced operation 22 6 7 Group Control 23 6 8 Slee...

Page 13: ...tion Drain pump X X X O O O X E S P control X X X X O O O Electric heater X X X X X X ANEH053B1 5kW ANEH103B2 10kW High ceiling operation X X X O X X X Auto Elevation Grille X X X X X X X Reliability Hot start O O O O O O O Self diagnosis O O O O O O O Soft dry operation O O O O O O O Convenien ce Auto changeover X X X X X X X Auto cleaning O O O X X X X Auto operation artificial intelligence O O ...

Page 14: ... switch X Phase protection X Restart delay 3 minutes O Self diagnosis O Soft start O Test function X Convenience Night Silent Operation O Network function Network solution LGAP O 1 2 List of Accessory Device Remark Central Controller Simple Controller X Function controller X Function Scheduler X AC Ez PQCSZ250S0 AC Smart ll PQCSW320A1E Option Kit SD card type PQCSE341A0 PQCSE342A0 ACP Advanced Con...

Page 15: ...flow direction control key input the left right louver automatically operates with the auto swing or it is fixed to the desired direction 2 2 Auto swing up down By the auto swing key input the upper lower vane automatically operates with the auto swing or it is fixed to the desired direction 2 3 Chaos swing up down By the Chaos swing key input the upper lower vane automatically operates with the c...

Page 16: ... the Jet Cool mode is operat ed In the Jet Cool mode the indoor fan is operated at super high speed for 30 min at cooling mode operation In the Jet Cool mode operation the room temperature is controlled to the setting temperature 18 C When the sleep timer mode is input while in the Jet Cool mode operation the Jet Cool mode has the priority When the Jet Cool key is input the upper lower vanes are r...

Page 17: ...stem not only removes microscopic contaminants and dust but also removes house mites pollen and pet fur to help prevent allergic diseases like asthma This filter that can be used over and over again by simply washing with water 3 Air purifying Ionizer Photo Catalyst Coated Mesh Dust particles Odour Dust electrode discharge Odour molecule Generating plasma Polluted Air Purified fresh Air 4 8KV disc...

Page 18: ...n Whenever pressing the button SLo Lo Med Hi Po will be indicated 2 Select the desired air flow rate value with the temperature up down button E S P value range 0 255 E S P value will be indicated at the upper right section of the display window 3 When pressing the button currently established E S P value will be set up 4 When pressing the button and button simultaneously for more than 3 seconds a...

Page 19: ...operation When the dehumidification operation input by the remote control is received the intake air temperature is detected and the setting temp is automatically set according to the intake air temperature While compressor off the indoor fan repeats low airflow speed and stop While the intake air temp is between compressor on temp and compressor off temp 10 min dehumidification opera tion and 4 m...

Page 20: ...sor depend on the load condition The difference between the room temp and set temp frequency restrictions If compressor operates at some frequency the operating frequency of compressor cannot be changed within 30 sec onds Condition of compressor turned off When intake air temperature reaches 4 C above the setting temperature Condition of compressor turned on When intake air temperature reaches 2 C...

Page 21: ...emp the compressor is turned off When 0 5 C or more above the setting temp the compressor is turned on Compressor ON Temp Setting Temp 0 5 C Compressor OFF Temp Setting Temp 0 5 C At the beginning of Fuzzy mode operation the setting temperature is automatically selected according to the intake air temp at that time 26 C Intake Air Temp 25 C 24 C Intake Air Temp 26 C Intake Air Temp 1 C 22 C Intake...

Page 22: ... 3 Fuzzy Operation for Heating According to the setting temperature selected by Fuzzy rule when the intake air temp is 3 C or more above the setting temp the compressor is turned off When below the setting temp the compressor is turned on Compressor ON Temp Setting Temp Compressor OFF Temp Setting Temp 3 C At the beginning of Fuzzy mode operation the setting temperature is automatically selected a...

Page 23: ... C 24 C Setting speed of indoor fan High speed Operating Mode Cooling Healthy Dehumidification Heating It is the function to use preventing children or others from careless using FAN SPEED FAN SPEED FAN SPEED During the operation when pressing the button and button for approx 3 seconds the Child Lock Function can be used At the time of initial setting of the Child Lock the CL Will be indicated app...

Page 24: ...nication function with one remote controller you must change the master slave setting from the indoor unit Indoor units the master slave configuration of the product after completion of indoor unit power OFF and then ON the power after 1 minutes elapsed sign up For ceiling type cassette and duct product group change the switch setting of the indoor PCB For wall mount type and stand type product ch...

Page 25: ...e remote control the appliance starts to operate The timer LED is on when the on timer is input It is off when the time set by the timer is reached If the appliance is operating at the time set by the timer the operation continues While in Fuzzy operation the airflow speed of the indoor fan is automatically selected according to the temperature 6 9 2 Off Timer Operation When the set time is reache...

Page 26: ... has been completed the setting mode will be released If there isn t any button input for more than 25 seconds the installer setting mode will also be released 4 OPER MODE OPER MODE Code value Setting value 01 Remote controller 02 Indoor unit 03 2TH OPER MODE Value TEMP FAN SPEED OPER MODE The function of 2TH has different operation characteristics according to the product Thermistor Table This is...

Page 27: ...lled easily regarding any space environment 7 3 Auto Elevation Grille Auto Elevation Grille is automatically down to height of max 3 1 m So it enables to install the Indoor unit at high ceiling space And Auto Elevation Grille makes you cleaning the filter easily 7 1 Low Ambient control This Function is for cooling operating in outdoor low temperature If outdoor temperature drops below certain temp...

Page 28: ...ont panel directly under front panel Do not drop it down or into water Or else there is worry about trouble failure Do not press hard the Remote Controller button with nail ball point pen or other sharp substance Or else there is worry about trouble failure In case when obstacle such as curtain hides the signal reception part of receiver in between the space interval Remote Controller operation is...

Page 29: ...tic Stop Distance of Grill Ceilingheight Low Medium High Height 3 4m Automatic stop distance 1 5 0 5m 2 5 0 5m 3 5 0 5m Depress the down button Then suction grill descends and stops automatically at a certain distance You may stop it at wanted distance point by depressing the stop but ton when descending Depress the up button Then suction grill goes up and enters into the front panel 1 Stop the Ai...

Page 30: ...Control Part 3 Basic Control 1 Normal operation 30 2 Compressor control 30 3 EEV Electronic Expansion Valve control 30 4 Oil return control 31 5 Defrost control 31 6 Protection control 32 6 1 High pressure protection control 32 6 2 Low pressure protection control 32 6 3 Discharge temperature control 32 6 4 Input Current control 32 ...

Page 31: ...ration Heating operation Stop state Compressor Fuzzy control Fuzzy control Stop Fan Fuzzy control Fuzzy control Stop EEV Super heating fuzzy control Super heating Sub cooling fuzzy control Min Pulse EEV operates with fuzzy control rules to keep the degree of superheat about 2 3 at the evaporator outlet status The degree of superheat Tsuction Tevaporation Tsuction temperature at suction pipe sensor...

Page 32: ...5 Defrost control Component Starting Running Ending Compressor Normal control Setting value Normal control Fan Normal control Off Normal control EEV Thermo on Normal control Setting value Normal control EEV Thermo off Min Pulse Setting value Min Pulse 4 way valve On Off On Component Starting Running Ending Fan Normal control Off Normal control Defrost signal Off On Off Outdoor unit Indoor unit Com...

Page 33: ...Pd 3709 kPa 3 Hz up Pd 3611 kPa Normal control Pressure range Compressor Pe 310 kPa Normal control 278 kPa Pe 310 kPa 3Hz down 245 kPa Pe 278 kPa 3Hz down 212 kPa Pe 245 kPa 3Hz down Pe 212 kPa Off Pressure range Compressor Pe 294 kPa Normal control 255 kPa Pe 294 kPa 3Hz down 229 kPa Pe 255 kPa 3Hz down 203 kPa Pe 229 kPa 3Hz down Pe 203 kPa Off 6 3 Discharge temperature control Temperature range...

Page 34: ...ight 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Part 4 Test Run Part 4 Test Run 1 Check before Test Run 34 2 Test Run Flow chart 35 3 Test Running 36 ...

Page 35: ...r supply terminal block and ground Do not operate in the case of 2 0 MΩ or less NOTE Never carry out mega ohm check over terminal control board Otherwise the control board may break Immediately after mounting the unit or after leaving it turned off for an extended length of time the resistance of the insulation between the power supply terminal board and the ground maydecrease to approx 2 0 MΩ as ...

Page 36: ...n start Refer to part4 6 Electric part Yes No Yes Refer to part4 5 Cycle part No Is hot air discharged After Hot Start Yes No Is there any temperature difference between intake and discharged air Yes No Is the operating current normal Yes Normal Refer to Troubleshooting Guide No Check the load In Out Temp Check pipe length and amount of refrigerant Check for abnormal sound in outdoor unit comp Fan...

Page 37: ... minutes without fail Test run will be cancelled 18 minutes later auto matically The forced operation is started by pressing button for 2 seconds The test run is started by pressing button for 3 6 sec onds To cancel the test run press any button 3 1 3 Settlement of outdoor unit Anchor the outdoor unit with a bolt and nut ø10mm tightly and horizontally on a concrete or rigid mount When installing o...

Page 38: ...tton and down timer button for 3 seconds at the same time To cancel the test run press any button 3 2 2 CHECK THE FOLLOWING ITEMS WHEN INSTALLATION IS COMPLETE After completing work be sure to measure and record trial run properties and store measured data etc Measuring data are room temperature outside temperature suction temperature blow out temperature air velocity air volume voltage current pr...

Page 39: ...1 2 Error Indicator Outdoor 40 2 Pump Down 41 3 Evacuation 42 4 Gas Charging 43 5 Cycle Part 44 6 Electronic Parts 45 6 1 The Product doesn t operate at all 45 6 2 The Product doesn t operate with the remote controller 46 6 3 The Compressor Outdoor Fan are don t operate 47 6 4 When indoor Fan does not operate 48 6 5 When the louver does not operate 49 6 6 Troubleshooting Indoor Error 50 6 7 Troubl...

Page 40: ...error occurrence if error is released error LED is also released simultaneously To operate again on the occurrence of error code be sure to turn off the power and then turn on Having or not of error code is different from Model Indoor Error 00 No Error ON 01 Indoor Room themistor error OFF 02 Indoor in piping sensor error OFF 03 Remote controller error OFF 04 Drain Pump error OFF 05 Communcation e...

Page 41: ... D Pipe Temp High Off 35 Low Pressure Error 3times 5times Excessive decrease of Low Pressure Off 39 Communication Error 3times 9times Communication Error Between PFC Micom and INV Micom Off 40 CT Sensor Open Short 4times CT Circuit Malfunction Off 41 INV D Pipe Th Error 4times 1times Open Short Off 43 High Pressure Sensor Error 4times 3times Open Short Off 44 Outdoor Air Th Error 4times 4times Ope...

Page 42: ... the Dip switch as follow after shutting the power source down 2 Reset the power 3 Check that the Red LED of PCB is on during work The indoor unit is operated by force 4 Pump down during forced cooling operation CAUTION 1 Use pump down function within guaranteed temperature range IDU 20 32C ODU 0 40C 2 Make certain that IDU doesn t run with thermo off mode during operation 3 After the compressor i...

Page 43: ...gauge needle does not move approxima tely 5 minutes after turning off the vacuum pump 4 Disconnect the charge hose from the vacuum pump Vacuum pump oil If the vacuum pump oil becomes dirty or depleted replenish as needed WARNING Use a vacuum pump or lnert nitrogen gas when doing leakage test or air purge Do not compress air or Oxygen and do not use Flammable gases Otherwise it may cause fire or ex...

Page 44: ...ith a little at a time approximately 150g each time while operating the air conditioner in the cooling cycle however one time is not suffi cient wait approximately 1 minute and then repeat the procedure pumping down pin 4 Immediately disconnect the charge hose from the 3 way valve s service port Stopping partway will allow the gas to be discharged If the system has been charged with liquid refrig ...

Page 45: ...erence between intake and discharge air depends on room air humidity When the room air humidity is relativery higher temperature difference is smaller When the room air humidity is relatively lower temperature difference is larger 2 Check temperature and pressure of refrigeration cycle in cooling mode 1 The suction pressure is usually 8 5 9 5kg cm2G Cooling at normal condition R410A 2 The temperat...

Page 46: ...Remedy 1 Check the power outlet 2 Replace PCB Assembly 4 Replace PCB Assembly 5 Replace PCB Assembly Turn on the main power again Turn off the main power and wait for 10 seconds Yes No A Beeping sound is made from the indoor unit Check the voltage of power supply AC220V AC240V 50Hz and check for the following The voltage of main power supply The voltage applied to the unit The connecting method of...

Page 47: ...d is made from the indoor unit Refer to 10 1 Check the voltage of power AC220V AC240V 50Hz Is it possible to turn on the unit by ON OFF button on display Yes No Is the remote controller working properly Yes When the mark is displayed in LCD screen replace battery No Check the contact point of CN DISP 1 2 connector Re connector Check display PCB Assembly Voltage between CN DISP1 should be DC 5V If ...

Page 48: ...e in bad connection or are not engaged Compressor Outdoor fan is stopped Check the related circuit of R02H 12 1K R01H 1K R04H 6 2K R03H 1K C01H 102 C02H 102 Micom pin No Check the Indoor temperature sensor is disconnected or not about 10K at 25 C Check the Relay RY PWR RY START for driving Compressor Check the voltage between brown and blue cable of terminal to connect the Outdoor About AC220V 240...

Page 49: ...main power Check the connection of CN FAN Check the Fan Motor Check the Fuse AC250V T2A Turn on the main power Check the related circuit of indoor Fan Motor The pin No 38 of micom and the part for driving SSR Q01M Check the related pattern Check the SSR SSR Open Indoor Fan Motor never operate SSR short Indoor Fan Motor always operates in case of ON or OFF The voltage of Pin No 1 orange and 3 black...

Page 50: ... Connector Check the soldering condition on PCB of CN U D or CN0L R Connector Check the operating circuit of the vertical louver Confirm that there is DC 12V between pin of CN U D CN0L R and GND Confirm that there is a soldering short at following terminals Between 1 2 3 and 4 of MICOM Between 17 18 19 and 20 of MICOM Between 4 5 6 and 7 of IC01M Between 5 6 7 and 8 of IC01M 6 5 When the louver do...

Page 51: ...ugged Normal resistor 5KΩ at 25 C Unplugged Normal voltage DC 2 5V at 25 C plugged Normal resistor 5KΩ at 25 C Unplugged Normal voltage DC 2 5V at 25 C plugged Display code Title Cause of error Check point Normal condition Check Point 1 Unplug the sensor on Indoor unit PCB 2 Estimate the resistance of each sensor 3 If the resistance of the sensor is 10KΩ 5KΩ at 25 C then sensor is normal 4 If the ...

Page 52: ... Wrong connection Connection of wire Main PCB Volt DC12V Noise interference Display code Title Cause of error Check point Normal condition Check Point 1 Check the wire connection Open Short Repair the connection 2 Check the soldering state of connector Soldered poorly Repair or Change the PCB 3 Check the volt Of main PCB power source DC 12V Repair or Change the main PCB 4 Check the installation of...

Page 53: ...e Drain pump Float switch Drain pump power input 230V Drain tube installation Indoor unit installation Inclination Display code Title Cause of error Check point Normal condition Check Point 1 Check the wire connection Open Soldered poorly Repair the connection or change the PCB 2 Check the resistance of float switch Abnormal Open Normal short Check the float switch 3 Check the level of water 4 Che...

Page 54: ...nother Unit operate heating At the same time this model cannot use cool and heating mode Display code Title Cause of error Check point Normal condition Check Point 1 Check another indoor model operation mode 2 Operating the same mode with the first operated indoor unit 3 Clearing the CH07 Press the on off button or mode change button and matching the indoor unit mode same as the first operated ind...

Page 55: ...or 1 Check the poor soldering 2 Check the insertion condition of the EEPROM 3 Check the PCB Connection Display code Title Cause of error Check point Normal condition Check Point 1 Check the EEPROM Direction 2 If the EEPROM value the Program value are not matched the Code is Displayed 3 After Checking the connection and Insertion replace the PCB or Option PCB EEPROM Direction Check Point ...

Page 56: ...Voltage is about input voltage x 1 414 if the Voltage does not come with the above Voltage Check the power input Replace the PCB Motor 2 Check the Voltage Black line to White the Voltage is DC 15V Check the Power input Replace the motor Check the Motor 1 Check the shaft if the shaft is not turn smoothly the Motor Power IC is defected replace the motor 2 Check the motor resistance if the shaft is t...

Page 57: ...code Title Cause of error Check point Normal condition 21 High current into the compressor Compressor blocked Disconnection shortcircuit inside compressor Over load operation Outdoor fan constraint screened blocked Burned parts inside PCB Check compressor constraint Check compressor wire open short Check compressor insulation damage Check outdoor fan constraint screened flow structure Check if IPM...

Page 58: ...and service purposes LGE Internal Use Only Part 5 Trouble Shooting IPM Position Pin number Model Resistance Ω Terminal Inverter Comp 18 24k U V 1 125 at25 V W 1 125 at25 W U 1 125 at25 Resistance of terminal insulations U chassis 1MΩ V chassis 1MΩ W chassis 1MΩ Table 1 Table 1 ...

Page 59: ...w voltage Over load operation Outdoor fan constraint screened blocked Burned parts inside PCB Check input voltage Check outdoor fan canstraint screened flow structure Check PCB current sensor parts 5V_GND 5V_GND 5V_GND DC_LINK WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off When measuring at standby state of power supply after checking the measu...

Page 60: ...k Voltage is above 420Vdc DC Link Voltage is below 140Vdc Check Input Voltage Check PCB DC Link voltage sensor parts 5V_GND 5V_GND 5V_GND DC_LINK Recheck power and installation condition Yes WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off When measuring at standby state of power supply after checking the measurement mode of the meter be careful ...

Page 61: ...ge sensing part Error Diagnosis and Countermeasure Flow Chart Yes Yes Recheck power and installation condition Yes Are there any power wire connections normal No Yes 1 Check L N G wiring conditions Rewire them if abnormality found Is input voltage normal No Check R S S T T R phase voltage is 220V 10 Check connection condition and wiring if power is abnormal Is main PCB assembly power connection no...

Page 62: ...rned parts inside PCB IPM Burned PCB phase current sensing circuit parts Check compressor locking Compressor wire open short Check compressor insulation damage Check outdoor fan constraint screened flow structure Check if IMP burned refer to CH21 Check on PCB current sensing circuit parts 5V_GND 5V_GND 5V_GND DC_LINK Recheck power and installation condition Yes WARNING Before checking PCB or each ...

Page 63: ...e of Gate collector Emitter collector 4 If the measurements are 1MΩ the parts are decided as burned Is the unit properly installed Check fan locking Remove blockings around heat exchanger Maintain distance between outdoor unit and the wall Check pipe folding and abnormality Check service valve lock Remedy remove cause of error Remedy replace reactor Remedy replace PCB Assembly Check Reactor spec 1...

Page 64: ...d parts inside PCB IPM Burned PCB phase current sensing circuit parts Check compressor locking Compressor wire open short Check compressor insulation damage Check outdoor fan constraint screened flow structure Check if IMP burned refer to CH21 Check on PCB current sensing circuit parts 5V_GND 5V_GND 5V_GND Comp_Current Recheck power and installation condition Yes WARNING Before checking PCB or eac...

Page 65: ...eakage insufficient Poor INV Comp Discharge sensor LEV connector displaced poor LEV assembly Check outdoor fan constraint screened flow structure Check refrigerant leakage Check if the sensor is normal Check the status of EEV assembly CN DISCHARGE BLACK 3Pin Connector Replace the Thermistor Yes WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off Whe...

Page 66: ...s No Is amount of refrigerant normal refer refrigerant part Yes No Is fan normal in heating outdoor fan in cooling indoor fan Yes Adjust the amount of refrigerant Additive charge check communication piping correction Check and replace related parts error 105 108 reference Is strainer Ok No Replace the strainer No Replace the pressure sensor Yes Yes Check indoor outdoor unit LEV Check Indoor unit P...

Page 67: ...ent on the input current Fig 1 at the power on standby state DC 0V 0 2V Remedy remove cause of error DC voltage measurement at the measurement point in figure 2 at power on standby state measured value within 2 5V 0 2V Remedy remove cause of error Is the Comp phase Current sensor part normal 5V_GND 5V_GND 5V_GND Input_I 5V_GND 5V_GND 5V_GND Comp_Current Recheck power and installation condition Yes...

Page 68: ...or 5KΩ at 25 C Unplugged Normal resistor 5KΩ at 25 C Unplugged Normal resistor 5KΩ at 25 C Unplugged Display code Title Cause of error Check point Normal condition Is sensor PCB conn ected to main PCB correctly Connect sensor PCB to main PCB correctly Remedy reassemble the sensor Check the status of the PCB connector assembly Check the status of the sensor assembly Remedy reassemble the sensor Is ...

Page 69: ... high pressure Abnormal value of sensor Open Short Bad connection of connector PCB Bad connection high pressure connector Defect of high pressure connector Open Short Defect of connector PCB Open Short Defect of outdoor main PCB Is sensor connected to PCB correctly Connect sensor to PCB correctly Replace corresponding pressure sensor Yes No No Yes END After replacement of outdoor unit main PCB is ...

Page 70: ... Check Point CH 51 1 Check the indoor unit capacity 2 Check the combination table Display code Title Cause of error Check point Normal condition 51 Over capacity Over capacity Combination Check the indoor unit capacity Check the combination table Model Gross max capacity Max single indoor unit capacity A2UW18GFA0 24k 18k A3UW24GFA0 33k 24k ...

Page 71: ...caused by external noise Indoor outdoor unit com munication circuit parts burned Check indoor unit power status Check indoor outdoor unit power communication line disconnection Check the status of indoor outdoor unit ground connections Check if outdoor unit communication parts are burned Recheck power and installation condition Yes WARNING Before checking PCB or each outdoor electric parts wait fo...

Page 72: ...ied Outdoor unit PCB EEPROM poor assmbly EEPROM assembly EEPROM Direction Check Point Inspecting Outdoor EEPROM Assembly Status 1 Check the consistency of the EEPROM s direction inserted in the PCB and the EEPROM marking Replace EEPROM Yes WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off When measuring at standby state of power supply after check...

Page 73: ... EEV connector displaced poor EEV assembly Poor Cond Pipe sensor assembly burned Check outdoor fan constraint screened flow structure Check if refrigerant overcharged Check the status of EEV assembly Check the status of sensor assembly burn CN C PIPE Violet 3Pin Connector Replace the Thermistor Yes WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off...

Page 74: ...t Is installation condition normal No Yes 1 Check fan locking 2 Check covering of heat exchanger 3 Check distance between ODU and obstacles 4 Check pipe distortion and abnormality 5 Check service valve is opened Eliminate causes for abnormal condition Check resistance between NO 14 pin and NO 16 pin of IPM module 85kΩ 6 3 at 25 Replace main PCBA it abnormality found Is assemble condition of INV PC...

Page 75: ... Check fan locking 2 Check covering of heat exchanger 3 Check distance between ODU and obstacles 4 Check pipe distortion and abnormality 5 Check service valve is opened Eliminate causes for abnormal condition Check resistance between NO 14 pin and NO 16 pin of IPM module 85kΩ 6 3 at 25 Replace main PCBA it abnormality found Is assemble condition of INV PCB heatsink normal Is PCB temperature sensin...

Page 76: ...or assemble condition and fan locking Reassemble or replace if abnormality found Is ODU Fan Motor normal No Yes 1 Set the multi tester to diode mode 2 Check voltage between 1pin and 4pin of Fan Motor 1Ţ0 2V 3 Replace Inverter PCB if abnormality found Is wire connection of ODU Fan Motor wire normal No Yes Check wiring between OUD fan motor and Inverter PCB Check if Hall Senor and Motor output termi...

Page 77: ...ace compressor if abnormality found Are the resistance Between each phase and insulation resistance of Inverter compressor normal No Yes 1 Check inverter PCB assembly U V W connector connection condition 2 Check wire disconnection and wiring 3 Check compressor terminal connection condition bad contact Reassemble if abnormality found Is compressor Wire connection condition normal No Yes Check inver...

Page 78: ...er off 2 Pull out V V W COMP connector 3 Set multi tester to resistance mode 4 If the value between P and N terminal of IPM is short 0Ω or open hundreds MΩ PCB needs to be replaced IPM damaged 5 Set the multi tester to diode mode 6 In case measured value is different from the table PCB needs to be replaced PCB damaged 27 26 25 24 23 22 21 P U V W Nu Nv Nw 0 4 0 6 V 27 26 25 24 23 22 21 P U V W Nu ...

Page 79: ...until inverter PCB DC voltage is discharged after main power off 2 Pull out CN L CN N connectors and U V W COMP Connector 3 Set multi tester to resistance mode 4 If the value between P and N terminal of IPM is short 0Ω or open hundreds MΩ PCB needs to be replaced IPM damaged 5 Set the multi tester to diode mode 6 In case measured value is different from the table PCB needs to be replaced PCB damag...

Page 80: ...ring again if abnormality found Yes Is input voltage normal No Check L N phase is 230V 15 Check connection condition and wiring if power is abnormal Yes Is inverter PCB assembly normal No Check inverter PCB assembly IPM normality Replace inverter PCB assembly Are the resistance Between each phase and insulation resistance of Inverter compressor normal No 1 Check resistance between each terminal of...

Page 81: ...nly Check Point 1 Check the power source 230V 15 2 Check the fan operation is right 3 Check the current 4 Check the install condition 5 Check the CT Sensor Output signal 36k Check output the CT Sensor DC 2 5 0 2V 54k Check output pin 1 2 of the CT Sensor 5V IN I GND CT Sensing Check Point Black Red Vdc CT Sensing Check Point Inverter PCB ...

Page 82: ...Error Diagnosis and Countermeasure Flow Chart Is Inverter PCB assembly Power connection normal No Check connection from terminal block to Inverter PCB assembly CN L CN N Yes Is input voltage normal No Yes Is Inverter PCB Normal No Replace inverter PCB assembly Recheck power and installation condition Yes Check L N Voltage is 230V 15 WARNING Before checking PCB or each outdoor electric parts wait f...

Page 83: ...ernal Use Only Check Point 1 Check the WCN_P L P N Connection condition at the Main PCB Refer to outdoor wiring diagram 2 Check the DC Link voltage at not operating 280V 3 Check the DC Link voltage at Comp operating 340V 4 Check DC Link Sensing Signal 2 4 2 8V Refer the Picture IN I GND CT Sensing Check Point Black Red Vdc 36k ...

Page 84: ...Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Vdc Vdc Inverter PCB DC Link Voltage Check Point Connection Check Point GND GND GND GND DC_LINK Sensing Check Point N N 54k L L DC_LINK DC_LINK DC_LINK ...

Page 85: ...utput voltage 2 5Vdc 10 25 Input voltage Abnormal Input voltage 140Vac 300Vac Check the power source Check the components Display code Title Cause of error Check point Normal condition Is Inverter PCB Normal No Replace inverter PCB assembly Is input voltage normal No Check L N Voltage is 230V 15 Yes Input Power Source Check Point Recheck power and installation condition Yes Error Diagnosis and Cou...

Page 86: ...4 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Inverter PCB Input Voltage Sensing Check Point GND GND INPUT V INPUT V INPUT V 36k 54k Vdc GND IN I GND CT Sensing Check Point Black Red Vdc ...

Page 87: ... 0 628 7 2 Check insulation resistance between compressor terminal and pipe over 2MΩ Replace compressor if abnormality found Are the resistance Between each phase and insulation resistance of Inverter compressor normal No Yes 1 Check inverter PCB assembly U V W connector connection condition 2 Check wire disconnection and wiring 3 Check compressor terminal connection condition bad contact Reassemb...

Page 88: ...ormal operation 4 Check refrigerant pressure Reassemble or manage if abnormality found Is installation condition normal Is compressor Wire connection condition normal 1 Check inverter PCB assembly U V W connector connection condition 2 Check wire disconnection and wiring 3 Check compressor terminal connection condition bad contact Reassemble if abnormality found Is AC input Wire connection conditi...

Page 89: ... Is input voltage normal No Check L N phase is 230V 15 Check connection condition and wiring if power is abnormal Yes Is inverter PCB assembly normal No Check inverter PCB assembly IPM normality Replace inverter PCB assembly Are the resistance Between each phase and insulation resistance of Inverter compressor normal No 1 Check resistance between each terminal of compressor 0 438 0 628 7 2 Check i...

Page 90: ...ked Refrigerant leakage insufficient Poor INV Comp Discharge sensor LEV connector displaced poor LEV assembly Check outdoor fan constraint screened flow structure Check refrigerant leakage Check if the sensor is normal Check the status of EEV assembly CN_TH3 RED 4Pin Connector WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off When measuring at sta...

Page 91: ...d Open service valve Are communication cable piping normal Yes No Is amount of refrigerant normal refer refrigerant part Yes No Adjust the amount of refrigerant Additive charge check communication piping correction Is strainer Ok No Replace the strainer No Replace the pressure sensor Yes Yes Check indoor outdoor unit LEV Check Indoor unit PCB Check indoor outdoor unit installation conditions Yes I...

Page 92: ...tween PFC Micom and INV Micom 1 Micom defect Circuit defect 2 Different Micom S W Version 3 ODU inverter PCB assembly damage Display code Title Cause of error Check point Normal condition Error Diagnosis and Countermeasure Flow Chart Is Inverter PCB assembly normal No Replace inverter PCB assembly Is PFC Micom INV Micom S W Program normal No Upgrade Micom Program Yes Yes Recheck power and installa...

Page 93: ...Point Recheck power and installation condition Yes Error Diagnosis and Countermeasure Flow Chart 40 C T Sensor Error Initial current error Malfunction of current detection circuit Open Short Check CT Sensor output voltage 2 5Vdc 5 Display code Title Cause of error Check point Normal condition WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power is off When ...

Page 94: ... 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Inverter PCB CT Sensing Check Point GND GND INPUT CT INPUT CT INPUT CT 54k Vdc GND 36k IN I GND CT Sensing Check Point Black Red Vdc ...

Page 95: ...n Short Soldered poorly Internal circuit error 1 Bad connection of thermistor connector 2 Defect of thermistor connector Open Short 3 Defect of outdoor PCB 48 Condenser Out pipe sen sor Open Short Soldered poorly Internal circuit error 1 Bad connection of thermistor connector 2 Defect of thermistor connector Open Short 3 Defect of outdoor PCB Ω Check Point 1 Estimate the resistance of each sensor ...

Page 96: ... connector PCB Bad connection high pressure connector Defect of high pressure connector Open Short Defect of connector PCB Open Short Defect of outdoor main PCB Is sensor connected to PCB correctly Connect sensor to PCB correctly Replace corresponding pressure sensor Yes No Replace the pressure sensor Yes No No Yes END After replacement of outdoor unit main PCB is the system also abnormal Is press...

Page 97: ... Check Point CH 51 1 Check the indoor unit capacity 2 Check the combination table Display code Title Cause of error Check point Normal condition 51 Over capacity Over capacity Combination Check the indoor unit capacity Check the combination table Model Gross max capacity Max single indoor unit capacity A4UW36GFA0 48k 24k A8UW54GFA0 73k 36k ...

Page 98: ...etween communication line and GND Normal Over 2MΩ 4 Check the connector for communication is correctly connected 5 If one indoor unit is operated normally outdoor PCB is no problem Check the another indoor unit CH05 is displayed at indoor unit CH53 is displayed at outdoor unit 6 If all indoor unit is displayed CH05 but outdoor PCB not display CH53 Check the CN_COM and CN_POWER is correctly connect...

Page 99: ...asure Flow Chart Is EEPROM insertion normal No Yes Recheck power and installation condition 1 Check EEPROM insert direction connection condition 2 Check EEPROM Check SUM Replace if abnormality found Is inverter PCB assembly normal No Yes Replace inverter PCB assembly Yes MAIN PCB assembly normal No Replace MAIN PCB assembly Check Point Check the EEPROM Check sum Direction 36k WARNING Before checki...

Page 100: ...Part 5 Trouble Shooting 99 Copyright 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only MAIN PCB Inverter PCB EEPROM Direction Check Point 54k ...

Page 101: ...nnector displaced poor EEV assembly Poor Cond Pipe sensor assembly burned Check outdoor fan constraint screened flow structure Check if refrigerant overcharged Check the status of EEV assembly Check the status of sensor assembly burn CN C PIPE Violet 3Pin Connector Recheck power and installation condition WARNING Before checking PCB or each outdoor electric parts wait for 3 minutes after the power...

Page 102: ...ween ODU and obstacles 4 Check pipe distortion and abnormality 5 Check service valve is opened Eliminate causes for abnormal condition Check resistance between NO 19 pin and NO 20 pin of PFC module Check resistance between NO 24 pin and NO 25 pin of PFC module 7KΩ10 at 25 C Replace PCB if abnormality found Is assemble condition of INV PCB heatsink normal Is PCB temperature sensing part normal No N...

Page 103: ...G Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only PFCM Measuring resistance between No 19 20 pin IPM Measuring resistance between No 24 25 pin 36k 54k PFCM Measuring resistance between No 19 20 pin ...

Page 104: ...s opened Eliminate causes for abnormal condition Check resistance between NO 19 pin and NO 20 pin of PFC module Check resistance between NO 24 pin and NO 25 pin of PFC module 7KΩ 10 at 25 C Replace PCB if abnormality found Is assemble condition of INV PCB heatsink normal Is PCB temperature sensing part normal No No Yes Check assemble condition between INV PCB heatsink and PFC IPM module Reassemble...

Page 105: ... LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only PFCM Measuring resistance between No 19 20 pin IPM Measuring resistance between No 24 25 pin 36k 54k Location of SPM PSCM PFCM A PSCM PFCM B SPM ...

Page 106: ...ocking Reassemble or replace if abnormality found Is ODU Fan Motor normal No Yes 1 Set the multi tester to diode mode 2 Check voltage between 1pin and 4pin of Fan Motor 1Ţ0 2V 3 Replace Inverter PCB if abnormality found Is wire connection of ODU Fan Motor wire normal No Yes Check wiring between OUD fan motor and Inverter PCB Check if Hall Senor and Motor output terminal color is matched Reassemble...

Page 107: ...g 106 Copyright 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Inverter PCB Main PCB 54k 36k Tester Fan motor connector Check voltage betwen 1pin and 4pin of fan motor ...

Page 108: ... Indoor Outdoor Unit 3 Check EEV connector assemble condition normal operation 4 Check refrigerant pressure Reassemble or manage if abnormality found Is installation condition normal Is compressor Wire connection condition normal 1 Check inverter PCB assembly U V W connector connection condition 2 Check wire disconnection and wiring 3 Check compressor terminal connection condition bad contact Reas...

Page 109: ...108 Copyright 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Input Power Source Check Point Main PCB wiring Check Point N N L N L Noise Filter wiring Check Point L N 36k ...

Page 110: ... training and service purposes LGE Internal Use Only Noise Filter wiring Check Point Input Power Source Check Point L N Inverter PCB wiring Check Point L N 54k N N L L N L Noise Filter wiring Check Point Input Power Source Check Point L N Inverter PCB wiring Check Point L N 54k N N L L N L ...

Page 111: ... 110 Copyright 2014 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only Part 6 Service Order 1 PCB Service Order 111 Part 6 Service Order ...

Page 112: ... Order Remove Top Cover and Control Box Cover Remove PCB Screws 6ea Raise PCB and take terminals from PCB Take Terminals from PCB with a tool Replace New PCB Hang wires up on the Rib from Case and Insert PCB into Control Box Assemble C Box and Top Cover into a complete whole Re wire terminal Tighten PCB Screws 6ea A2UW18GFA0 A3UW24GFA0 1 4 7 2 5 8 3 6 9 ...

Page 113: ...P NO MFL68280201 January 2014 ...

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