LG SJ242CD Service Manual Download Page 1

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SERVICE MANUAL

Room Air Conditioner

CAUTION

BEFORE SERVICING THE UNIT, READ THE SAFETY

PRECAUTIONS IN THIS MANUAL.

ONLY FOR AUTHORIZED SERVICE PERSONNEL.

WEBSITE

http://biz.LGservice.com

Summary of Contents for SJ242CD

Page 1: ...SERVICE MANUAL Room Air Conditioner CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL ONLY FOR AUTHORIZED SERVICE PERSONNEL WEBSITE http biz LGservice com ...

Page 2: ...ng Diagram 12 Operation Details 14 Display Function 21 Installation 22 Operation 33 Disassembly of the parts Indoor Unit 34 2 way 3 way Valve 36 Cycle Troubleshooting Guide 44 Electronic Parts Troubleshooting Guide 45 Electronic Control Device 52 Exploded View and Replacement Parts List 57 2 ...

Page 3: ... speed The louver can be set at the desired position or swing up and down automatically Indoor Unit Operation ON OFF by Remote controller Sensing the Room Temperature Room temperature control Starting Current Control Time Delay Safety Control Indoor Fan Speed Control Soft Dry Operation Mode The function will be operated while in any operation mode with selecting the function The function is to be ...

Page 4: ...CHANGE EVAPORATOR HEAT EXCHANGE CONDENSER HEAT EXCHANGE CONDENSER COMPRESSOR COMPRESSOR ACCUMU LATOR GAS SIDE GAS SIDE VALVE LIQUID SIDE LIQUID SIDE VALVE CAPILLARY TUBE CAPILLARY TUBE CHECK VALVE Heating Model only COOLING HEATING REVERSING VALVE Heating Model Only 1 Cooling Only Models 2 Cooling Heating Models ...

Page 5: ...while in timer mode on off OFF when timer mode is completed or canceled Defrost Indicator OFF except when hot start during heating mode operation or while in defrost control Cooling Mode Operation When the intak e air temper ature reaches 0 5 C below the setting temp the compressor and the outdoor f an stop When it reaches 0 5 C above the setting temp they start to operate again Compressor ON Temp...

Page 6: ...y out defrost control or not and the time of defrost control are determined according to the following conditions 1 While in heating mode oper ation the maxim um of the indoor pipe temper ature is measured and it is com pared with the present indoor pipe temper ature to get the diff erence of the indoor pipe temper atures the maximum temperature of indoor pipe the present temper ature of indoor pi...

Page 7: ...or f an is oper ated for 15 seconds Then an oper ation mode is selected according to the intak e air temp at that moment as follows 24 C Inatake Air Temp Fuzzy Operation for Cooling 21 C Inatake Air Temp 24 C Fuzzy Operation for Dehumidification Inatake Air Temp 21 C Fuzzy Operation for Heating If any of the operation modes among cooling dehumidification heating mode operations is carried out for ...

Page 8: ... by Fuzzy r ule when the intak e air temp is 3 C or more abo ve 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 oper ation the setting temper ature is automatically selected according to the intake air temp at that time 20 C Intake Air Temp Intak...

Page 9: ...annot be input While in cooling mode oper ation 30 min later since the star t of the sleep timer the setting temper ature increases by 1 C After another 30 min elapse it increases by 1 C again When the sleep timer mode is input while in cooling cycle mode the airflow speed of the indoor fan is set to the low When the sleep timer mode is input while in heating cycle mode the airflow speed of the in...

Page 10: ...ing test operation if remote controller signal is received the unit operates as remote controller sets If you want to use this operation open the front panel upward and Press the power button let it be pressed for about 3 seconds If you want to stop the operation re press the button Auto restart In case the power comes on again after a power failure Auto Restarting Operation is the function to ope...

Page 11: ...r pipe from frosting When the indoor pipe temp is 7 C or higher after 3 min pause of the compressor the compressor and the outdoor fan is turned on according to the condition of the room temperature Buzzer Sounding Operation When the appliance operation key is input by the remote control the short beep beep sounds When the appliance pause key is input by the remote control the long beep sounds Whe...

Page 12: ...r pipe temperature thermistor open short Indoor Thermistor assembly check SVC check point 1 Heating Model 2 Cooling Model Cooling Soft Dry Fan Heating Cooling Soft Dry Fan Sleep Mode Sleep Mode Timer Mode Timer Mode Hot start Defrost Operation Indicator Timer Indicator Sleep Timer Indicator Defrost Indicator Operation Indicator Timer Indicator Sleep Timer Indicator Compressor Indicator ...

Page 13: ... noise and vibration are minimum Select a place so that the warm air and noise from the air conditioner do not disturb neighbors 2 Piping length and elevation Installation 1 Installation of indoor Outdoor unit 13 More than A More than B More than 2 3m More than B More than 10 cm More than 10 cm More than 70 cm Install the indoor unit on the wall where the height from the floors more than 2 3 meter...

Page 14: ...a hole in the wall Drill the piping hole with a ø70mm hole core drill Drill the piping hole at either the right or the left with the hole slightly slanted to the outdoor side m m 7 5 6 1 5 6 1 3 Indoor WALL Outdoor ...

Page 15: ...bing 3 Putting nut on Remove flare nuts attached to indoor and outdoor unit then put them on pipe tube having completed burr removal not possible to put them on after flaring work 4 Flaring work Firmly hold copper pipe in a die in the dimension shown in the table above Carry out flaring work using flaring tool as shown below 5 Check Compare the flared work with figure below If flare is noted to be...

Page 16: ... so that dripping from sweating condensation will not damage furniture or floors Foamed polyethylene or equivalent is recommended 4 Indoor unit installation Hook the indoor unit onto the upper portion of the installation plate Engage the two hooks of the rear top of the indoor unit with the upper edge of the instal lation plate Ensure that the hooks are properly seat ed on the installation plate b...

Page 17: ...r where they fit into the rear piping housing section 1 Route the indoor tubing and the drain hose to the required piping hole position 2 Insert the piping drain hose and the connecting cable into the piping hole For left rear piping mm inch kg m Ø6 35 1 4 1 8 Ø9 52 3 8 4 2 Ø12 7 1 2 5 5 Ø15 88 5 8 6 6 Ø19 05 3 4 6 6 Outside diameter Torque Wrench Indoor unit tubing Open end wrench fixed Connectio...

Page 18: ...nch When extending the drain hose at the indoor unit install the drain pipe 7 Wrap the insulation material around the con necting portion Overlap the connection pipe heat insulation and the indoor unit pipe heat insulation material Bind them together with vinyl tape so that there is no gap Wrap the area which accommodates the rear piping housing section with vinyl tape mm inch kg m Ø6 35 1 4 1 8 Ø...

Page 19: ...ess the lower left and right sides of the unit against the installation plate until the hooks engage into their slots clicking sound 3 Connection of the pipes Outdoor 1 Align the center of the pipings and sufficiently tighten the flare nut by hand 2 Finally tighten the flare nut with torque wrench until the wrench clicks When tightening the flare nut with torque wrench ensure the direction for tig...

Page 20: ...k 38k 0 75 1 0 1 5 2 5 2 5 5 5 Unit A Indoor Indoor Indoor Indoor Outdoor Outdoor CableType B H05VV F H05VV F H05VV F H05VV F H05RN F H05RN F NORMAL CROSS SECTIONAL AREA 5k 9k 12k 14k 18k 24k 28k 0 75 1 0 1 5 2 5 Cable Type B H07RN F H07RN F H07RN F H07RN F NORMAL CROSS SECTIONAL AREA Grade 30k 32k 36k 38k 0 75 0 75 Cable Type B H07RN F H07RN F NORMAL CROSS SECTIONAL AREA Grade mm2 mm2 mm2 The pow...

Page 21: ...fittings are liable to come loose from vibrations to which the unit is subjected during the course of transportation Check them and make sure that they are all tightly fastened If they are loose it could cause burn out of the wires 3 Specification of power source 4 Confirm that electrical capacity is sufficient 5 See to that the starting voltage is maintained at more than 90 percent of the rated v...

Page 22: ...the ground Secure the drain hose appropriately 2 In cases where the outdoor unit is installed below the indoor unit perform the following Tape the piping drain hose and connecting cable from down to up Secure the tapped piping along the exterior wall using saddle or equivalent 3 In cases where the Outdoor unit is installed above the Indoor unit perform the following Tape the piping and connecting ...

Page 23: ...ting 4 For reference the gas side pressure of optimum con dition is as below Cooling NOTE If the actual pressure is higher than shown the system is most likely over charged and charge should be removed If the actual pressure are lower than shown the system is most likely undercharged and charge should be added The air conditioner is now ready for use Bolt Tubing connection Discharge temperature Di...

Page 24: ...own air discharge louver to open position horizontally by finger pressure Remove the securing screws To remove the Grille pull the lower left and right side of the grille toward you slightly tilted and lift it straight upward 1 Before removing the control box be sure to take out the wire screwed at the other end Display P C B Conductor Step Motor Conductor Earth Conductor Motor Conductor Sensor Co...

Page 25: ...l ly 3 To remove the Discharge Grille Unhook the discharge g rille and pull the dis charge grille out from the chassis carefully 4 To remove the Evaporator Remove 3 screws securing the evaporator at the left 2EA in the Eva Holder at the right 1EA Caution label When repair do not damage the Caution label ...

Page 26: ...emove 2 securing screw Pull the motor cover out from the chassis carefully 6 To remove the Cross Flow Fan Loosen the screw securing the cross flow fan to the fan motor do not remove Lift up the right side of the cross flow fan and the fan motor separate the fan motor from the cross flow fan Remove the left end of the cross flow fan from the self aligning bearing Motor cover ...

Page 27: ... gauge Open Open Open with charging cylinder Open Open Open with charging cylinder Open Open Open Open Works Shipping Air purging Installation Operation Pumping down Transfering Evacuation Servicing Gas charging Servicing Pressure check Servicing Gas releasing Servicing 1 2 3 4 5 6 Valve cap Open position Closed position Pin Service port Service port cap To outdoor unit Flare nut To piping connect...

Page 28: ... hexagonal wrench to press the v alve core pin discharge for three seconds and then wait for one minute Repeat this three times 5 Use torque wrench to tighten the service port nut to a torque of 1 8kg cm 6 Set the 3 way valve to the back seat 7 Mount the valve stem nuts to the 2 way and 3 way valves 8 Check for gas leakage At this time especially chec k for gas leakage from the 2 w ay and 3 w ay v...

Page 29: ...e hose Open the low pressure valve on the charge set slightly to air purge from the charge hose 5 Set the 2 way valve to the closed position 6 Operate the air conditioner at the cooling cycle and stop it when the gauge indicates 1kg cm2 g 7 Immediately set the 3 way valve to the closed position Do this quickly so that the gauge ends up indi cating 3 to 5kg cm2 g 8 Disconnect the charge set and mou...

Page 30: ... on the 2 way valve 4 Check for gas leakage Check the flare connections for gas leakage 5 Discharge the refrigerant Close the v alve on the gas cylinder and dis charge the refrigerant until the gauge indicates 3 to 5 kg cm2 g 6 Disconnect the charge set and the gas cylin der and set the 2 way and 3 way valves to the open position Be sure to use a he xagonal wrench to oper ate the valve stems 7 Mou...

Page 31: ...and discharge the refrigerant until the gauge indicates 0 kg cm2 G If there is no air in the refrigerant cycle the pressure when the air conditioner is not run ning is higher than 1 kg cm2 G discharge the refrigerant until the gauge indicates 0 5 to 1 kg cm2 G if this is the case it will not be neces sary to apply a evacuatin Discharge the refrigerant gradually if it is dis charged too suddenly th...

Page 32: ...or less 3 Close the valve Lo side on the charge set turn off the vacuum pump and confirm that the 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 v acuum pump oil becomes dir ty or depleted replenish as needed Lo Open Open Vacuum pump 2 Way valve Outdoor unit Liquid side Indoor unit Gas s...

Page 33: ...r humidity When the room air humidity is relativery higher temperature difference is smaller When the room air humidity is relativ ely lower tem perature difference is larger 2 Check temperature and pressure of refrigeration cycle Notice 1 The suction pressure is usually 4 5 6 0 kg cm2 G Cooling at normal condition 2 The temper ature can be measured b y attaching the ther mometer to the lo w press...

Page 34: ...50g each time while oper ating the air conditioner in the cooling cycle ho wever one time is not suffi cient wait approximately 1 min ute and then repeat the procedure pumping down pin 4 Immediately disconnect the charge hose from the 3 way valve s service port Stopping par tway will allo w the gas to be dis charged If the system has been charged with liquid refrigerant while oper ating the air co...

Page 35: ...or ZNR01J Check the connection housing for contacting Connector related to CN TAB1 RY COMP NO 3 Connector related to CN MOTOR Connector contacting of Outdoor Fan Compressor Display PWB Assembly Check Check each load Indoor Outdoor F an Motor Com pressor Stepping Motor and contacting condition of related connector Main PCB Board Operation Check Items SMPS Transformer Indoor unit Input Voltage Outpu...

Page 36: ...tery Check the contact of CN DISP1 connector When the compressor stopped Indoor Fan is driven by a low speed At this point the wind speed is not controlled by the remote controller When operated in the Sleeping Mode the wind speed is set to the low speed by force Check Display PWB Assembly Voltage between CN DISP1 DC 5V Check the connecting circuit between the remote controller MICOM No R17 2Ω IR ...

Page 37: ...sor Outdoor Fan is stopped Check the related circuit of RY FAN Check the indoor temperature sensor is disconnected or not About 10kΩ at 25 C Turn off Main Power Check the electrical wiring diagram of outdoor side Check the abnormal condition for the component of Compressor Out door Fan Motor Check the open or short of conmecting wires between indoor and outdoor Check Relay RY COMP for driving comp...

Page 38: ...ircuit of indoor Fan Motor The pin NO 58 of Micom and the part for driving TRIAC the input and output signal of IC01M PIN NO 7 10 Check the pattern Check the TRIAC TRIAC Open Indoor Fan Motor never operate TRIAC short Indoor Fan Motor always operates in case of ON or OFF 4 When indoor Fan does not operate The voltage of PIN NO 1 orange and 3 yellow of CN MOTOR About AC 180V over About AC 50V over ...

Page 39: ...N U D Connector If there are no problems after above checks Confirm the assembly conditions that are catching and interfering parts in the rotation radial of the Vertical Louver 5 When Vertical Louver does not operate Check the operating circuit of the Vertical Louver Confirm that there is DC 12V between pin RED of CN U D and GND Confirm that there is a soldering short at following terminals Betwe...

Page 40: ...d or not about 10KΩ at 25 C Check the indoor pipe temperature is disconnected or not about 5KΩ at 25 C Turn ON Main Power Check the DC voltage on the PWB ASSEMBLY The details of check are as followings Check point Between Micom NO 59 and GND Between IC01M NO 11 and GND Comp ON DC 5V Below DC 1V Comp OFF DC 0V About DC 12V Check point Between Micom NO 51 and GND Between IC02M NO 11 and GND 4 way ON...

Page 41: ...in Power Check the electrical wiring diagram of outdoor side Check the abnormal condition for the component of Compressor Out door Fan Motor 4 way Check the open or short of connecting wires between indoor and outdoor ...

Page 42: ...Air Conditioner 1 Indoor Unit 135314 342800 359011 131410 733010 135316 135311 147581 268711A 146811 146811 147582 1 346810 W0CZZ 135516 35211B 354210 249951 267110 135511 352115 152302 135301 268711D W6640 263230 264110 249941 147582 2 ...

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