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Website : http://biz.lgservice.com
WASHING MACHINE
SERVICE MANUAL
CAUTION
READ THIS MANUAL CAREFULLY TO DIAGNOSE
PROBLEMS CORRECTLY BEFORE SERVICING THE UNIT.
MODEL: WM4270H*A
1

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Summary of Contents for LG WM4270HVA

  • Page 1 Website : http://biz.lgservice.com WASHING MACHINE SERVICE MANUAL CAUTION READ THIS MANUAL CAREFULLY TO DIAGNOSE PROBLEMS CORRECTLY BEFORE SERVICING THE UNIT. MODEL: WM4270H*A...
  • Page 2: Table Of Contents

    CONTENTS Specifications ..........................3 Features and Technical Explanation .................... 4-6 Parts Identification ........................... 7 Installation and Test ........................8-10 Operation ..........................11-17 5-1. Control Panel Features ..................... 11-13 5-2. Cycle Guide ........................... 14 5-3. Special Functions ........................15 5-4. Explanation of Each Process .................... 16-17 Test Mode ............................
  • Page 3: Specifications

    1. SPECIFICATIONS WM4270H*A COLOR Blue White, VCM POWER SUPPLY AC 120 V, 60 Hz PRODUCT WEIGHT 202.8lb (92kg) WASHING 240 W ELECTRIC POWER DRAIN MOTOR 80 W CONSUMPTION WASH HEATER 1000 W REVOLUTION WASH 46 rpm SPEED SPIN 0-1,300 rpm CYCLES WASH/RINSE TEMPERATURES SPIN SPEEDS...
  • Page 4: Features And Technical Explanation

    The motor assembly also contains fewer moving parts, thus resulting in fewer repairs. NFC (Tag On Function) This feature uses LG Smart DiagnosisTM, Cycle Download, and Laundry Stats when you touch the LG appliance’s Tag On logo with your NFC equipped smartphone.
  • Page 5 2-2. NEURO FUZZY WASHING TIME OPTIMIZATION To get the best washing performance, optimal time is determined by the water temperature, the selected washing temperature, and the size of the load. water temperature washing time the best selected NEURO- washing rinsing time washing FUZZY temperature...
  • Page 6 2-5. THE DOOR CAN NOT BE OPENED While program is operating. When a power failed and power plug is taken out in operation. While Door Lock lights turn on. White the motor is in the process of inertial rotating, through the operation is paused. 2-6.
  • Page 7: Parts Identification

    (sold separately) NOTE Contact LG Customer Service at 1-800-243-0000 (1-888-542-2623 in Canada) if any accessories are missing. For your safety and for extended product life, use only authorized components. The manufacturer is not responsible for product malfunction or accidents caused by the use of separately purchased unauthorized components or parts.
  • Page 8: Installation And Test

    4. INSTALLATION & TEST Before servicing, ask the customer what the trouble is. When installing or repairing the washer, put on long gloves and safety glasses. Check the setup (power supply is 120 V , remove the transit bolts, level the washer, etc.) Check with the troubleshooting guide.
  • Page 9 HOW TO CONNECT THE INLET HOSE Verify that the rubber washer is inside of the Cold valve connector. Tighten the inlet hose securely to prevent leaks. Install the inlet hose to correct temperature water tap. Otherwise, it cause drips on the drawer panel handle and drawer panel.
  • Page 10 7 TEST OPERATION Preparation for Press the POWER button. Press the START/PAUSE washing. button. • Connect the power plug to the outlet. • Listen for a click to determine if the • Connect the inlet hoses. door has locked. Check the water heating Check the automatic reverse Check the water supply.
  • Page 11: Operation

    5. OPERATION 5-1. CONTROL PANEL FEATURES WM4270H*A...
  • Page 12 Status Indicator Power Button • It shows elapsed time of the cycle the washer is • Use this button to turn the operating. power On/Off. Cycle Selector Knob Start/Pause • Rotate the Cycle selector knob to select the cycle • Use this button to designed for different types of fabric and soil Start/Stop the washer.
  • Page 13 Option Button • STEAM : Use the STEAM button to add steam to the cycle for the extra cleaning. PRE-WASH : Use the PREWASH button to select to wash temporary before to start the course which • you chosen. DELAY WASH : Once you have selected the cycle and other settings, press this button to delay the •...
  • Page 14: Cycle Guide

    5-2. Cycle Guide The cycle guide below shows the options and recommended fabric types for each cycle. ● = Available option BASIC OPTION (  =DEFAULT) ADDITIONAL OPTIONS DISPLAY CYCLE FABRIC TYPE Wash Spin Soil Pre- Extra Cold Turbo Fresh TIME(MIN) Steam Wash...
  • Page 15: Special Functions

    5-3. SPECIAL FUNCTIONS The option buttons also activate special functions, including CHILD LOCK, LOAD SIZE, TUB CLEAN, and SIGNAL ON/OFF. Press and hold the option button marked with the special function for 3 seconds to activate. CHILD LOCK Use this option to prevent unwanted use of the washer or to keep cycle settings from being changed while the washer is operating.
  • Page 16: Explanation Of Each Process

    5-4. Explanation of each process Stay • Electrical power is supplied. • Washer is ready to work and the micom is in the active mode. Water • After loading laundry and selecting a course and a cycle, water is supply supplied and drum rotates.
  • Page 17 Intermittent • To reach the correct set speed, the motor rotates clockwise and spin counterclockwise directions after spin process starts. • If the water level frequency is lower than 23.0 kHz, a washer senses suds and starts suds removal process. Rinse •...
  • Page 18: Test Mode

    6. TEST MODE 6-1. 6-2. SPIN SPEED SOIL LEVEL Turns on all lamps and locks the door. 6-3. WASH/RINSE DELAY WASH...
  • Page 19: Troubleshooting

    7. TROUBLESHOOTING 7-1. 7-2.
  • Page 20 ERROR SYMPTOM CAUSE • The connector (3-pin, male, white) in the MOTOR LOCKED MOTOR HARNESS is not connected to the connector (3-pin, ERROR female, white) of STATOR ASSEMBLY. • The electric contact between the connectors (3-pin, male, white) in the MOTOR HARNESS and 4-pin, female, white connector in the MAIN PWB ASSEMBLY is bad or unstable.
  • Page 21: Troubleshooting With Error

    7-3. TROUBLESHOOTING WITH ERROR INLET VALVE ERROR...
  • Page 22 DRAIN ERROR SPIN SPEED SOIL LEVEL, WASH/RINSE DELAY WASH...
  • Page 23 HEATING ERROR...
  • Page 24 - part of motor LOCKED MOTOR ERROR displayed? LE ERROR Reconnect Check the connectors below. Motor the connector. Is the connector disconnected (connector / or disassembled? wire / motor ) (motor hall sensor connector, Is rotor magnet cracked? Replace motor drive connector.) the ROTOR.
  • Page 25 DOOR OPEN ERROR Replace the Is there clicking sound once displayed? dE ERROR or twice when the ASSEMBLY. START/PAUSE button is pressed to start the cycle? Reconnect or Is the connector connected repair to door switch or main PWB Replace the Is DOOR SWITCH the connector.
  • Page 26 UNBALANCE ERROR OVER FLOW ERROR WASH/RINSE DELAY WASH [Note] Installation check list...
  • Page 27 PRESSURE SENSOR ERROR displayed? PE ERROR Reconnect or Is the connector connected repair to pressure sensor the connector. disconnected or disassembled? Replace the Is the resistance of the pressure pressure sensor out of switch. range? (pin 1~ pin 3) (21~23 Ω ±10%) Fix the air Is the AIR CHAMBER and chamber...
  • Page 28: Troubleshooting Else

    7-4. TROUBLESHOOTING ELSE CAUTION 1. Be careful of electric shock if disconnecting parts while troubleshooting. 2. First of all, check the connection of each electrical terminal with the wiring diagram. 3. If you replace the MAIN PWB ASSEMBLY, reinsert the connectors correctly. NO POWER Replace the Is LED on while the power...
  • Page 29 BUTTON DOESN’T WORK...
  • Page 31 DETERGENT DOES NOT FLOW IN Refer to Is water supplied? NO WATER SUPPLY. Are receptacles correctly Check the connected to the terminals wiring. of the INLET VALVE ASSEMBLY? Has detergent been put in Put the the correct compartment detergent in of the dispenser? the correct place.
  • Page 32 LIQUID DETERGENT/SOFTENER/ ABNORMAL SOUND BLEACH DOES NOT FLOW IN Refer to Secure the Is the motor bolt loosened? Is water supplied? NO WATER bolt. SUPPLY. Are the plugs correctly Check the connected to the terminals of wiring on the the INLET VALVE dispenser.
  • Page 33: Before Using The Tag On Function

    In some cases, NFC-equipped phones may be unable to transmit successfully. Press [ ] in the LG Smart Laundry&DW app for a more detailed guide on how to use the Tag On function.
  • Page 34: Component Testing Information

    8. COMPONENT TESTING INFORMATION When Resistance (Ohm) checking the Component, be sure to turn the power off, WARNING and do voltage discharge sufficiently. 8-1. FILTER ASSEMBLY (LINE FILTER) Wiring Circuit in the MAIN PWB / Wiring Diagram diagram MAIN PWB ASSEMBLY FUSE Test...
  • Page 35: Door Look Switch Assembly

    8-2. DOOR LOCK SWITCH ASSEMBLY Wiring Circuit in the MAIN PWB / Wiring Diagram diagram MAIN PWB MICOM Relay Relay Common terminal of valve Door switch The door lock switch assembly consists of a heating PTC, a bimetal, Function a protection PTC, and a solenoid. It locks the door during the wash cycle. 1.
  • Page 36 Test points (5) (3) Result Test Points Result Remarks (2) to (4) 700-1500 Ω At 77 °F °C (3) to (4) 60-90 Ω At 77 °F °C (4) to (5) Infinity (2) to (4) 120 Vac Voltage Input...
  • Page 37: Stator Assembly

    8-3. STATOR ASSEMBLY Wiring Circuit in the MAIN PWB / Wiring Diagram diagram MAIN PWB NA1NA MICOM Function The Direct Drive motor can be driven from stopped to maximum speed in infinite steps in either direction. There are 36 poles on the stator; 12 permanent magnets spaced around the rotor. There are no brushes to wear out.
  • Page 38 The hall sensor determines the speed and direction of the motor. It also can read that the load is off balance when the drum speed fluctuates. Test point - Voltage Testing Hall Sensor at Stator Result (Hall Sensor) (2) (4) (1) (3) (5) If measuring voltage from the Main PCB Assembly to the Hall Sensor, use the following steps:...
  • Page 39 7. To measure output signal voltage from the hall sensor, carefully move test leads to terminals 1 to 4, blue and gray. Slowly rotate motor rotor by hand. You should read a pulsing 10 V . If 10 V is measured from 1 to 4, move lead on blue wire to red wire, terminal 2.
  • Page 40: Pump Motor Assembly

    8-4. PUMP MOTOR ASSEMBLY Wiring Circuit in the MAIN PWB Wiring Diagram diagram MAIN PWB 1 2 3 1 2 3 1 2 3 4 1 2 3 3 2 1 MICOM 3 2 1 CONNECTOR Pump Driving circuit DRAIN CIRCULATION PUMP PUMP...
  • Page 41: Inlet Valve Assembly

    8-5. INLET VALVE ASSEMBLY...
  • Page 42: Heater Assembly

    8-6. HEATER ASSEMBLY Wering Circuit in the MAIN PWB Wiring diagram diagram * Each circuits of loads in wiring diagram are all same. Function 1. The wash heater is designed to raise the wash water to the desired temperature selection during certain wash cycles. Test points Result Wash Heater...
  • Page 43: Thermistor Assembly

    8-7. THERMISTOR ASSEMBLY Circuit in the MAIN PCB / Wiring Diagram...
  • Page 44 Result Wash Thermistor Test Points Result Remarks (tolerance ±5%) (1) to (2) At 86°F (30°C) 39.5 kΩ At 104°F (40°C) 26.1 kΩ 12.1 kΩ At 140°F (60°C) At 158°F (70°C) 8.5 kΩ 3.8 kΩ At 203°F (95°C) At 221°F (105°C) 2.8 kΩ...
  • Page 45: Disassembly Instructions

    9. DISASSEMBLY INSTRUCTIONS Be sure to unplug the machine before disassembling and repairing the parts. CONTROL PANEL 1 Unscrew 2 screws on the back of the top plate. TOP PLATE ASSEMBLY 2 Pull the top plate backward and upward as shown.
  • Page 46 MAIN PWB ASSEMBLY Disconnect the POWER connector and the pressure switch assembly. Remove the protective cover. PROTECT COVER Disconnect the connectors. Unscrew 1 screw on the back. Remove the main PWB.
  • Page 47 DISPENSER ASSEMBLY Disassemble the top plate assembly. Pull out the drawer. Push out the dispenser assembly after unscrewing 2 screws. DRAWER Unscrew the clamp nut at the lower part of the dispenser. Disassemble the 4 connectors from the valves. Wire Color Blue Housing (YL-BK) White Housing (WH-BK) Blue Housing (GY-BK)
  • Page 48 CABINET COVER Unscrew the 5 screws from upper of the cabinet cover. Unscrew the screw from the filter cover. Put a flat ( - ) screwdriver or putty knife into the hinge slots at the bottom of the cover and pry it out.
  • Page 49 Open the door. Disassemble the clamp assembly. Tilt the cabinet cover. Disconnect the door switch connector. NOTE : When assembling the cabinet cover, connect the door switch connector. Lift and separate the cabinet cover. Disassemble the clamp assembly. Disassemble the gasket.
  • Page 50 DOOR Open the door. Unscrew the 4 screws from the hinge. (Use the 8mm tool.) Disassemble the door upward. DOOR LOCK SWITCH ASSEMBLY Open the door and remove the gasket using the special gasket pliers. Unscrew the 2 screws. NOTE •...
  • Page 51 PUMP Disassemble the cabinet cover. CIRCULATION Separate the pump hose, the bellows, the HOSE circulation hose assembly from the pump PUMP HOSE assembly. BELLOWS Disassemble the pump assembly. HEATER Disassemble the cabinet cover. Separate 2 connectors from the heater. Loosen the nut and pull out the heater. CAUTION •...
  • Page 52 WHEN FOREIGN OBJECT IS STUCK BETWEEN DRUM AND TUB Disassemble the cabinet cover. Separate the heater from the tub. Remove any foreign objects (wire, coin, etc.) by inserting a long bar in the opening. LAMP ASSEMBLY Unscrew 2 screws on the back of the top plate. TOP PLATE ASSEMBLY Pull the top plate backward and upward as shown.
  • Page 53 MOTOR/DAMPER Disassemble the back cover. Rotor Remove the bolt. Pull out the rotor. Bolt Unscrew the 2 screws from the tub bracket. Remove the 6 bolts on the stator. Unplug the 2 connectors from the stator. Disassemble the damper hinges from the tub DAMPER HINGE, and base.
  • Page 54: Exploded View

    11. EXPLODED VIEW 11-1. CABINET & CONTROL PANEL ASSEMBLY M410 F215 A485 *Non-Skid pads G010 F210 F110 A455 A450 A104 A105 A106 A102 A111 A110 A410 A103 A150 A154 A152 A101 A141 A390 A151 A156 A153 A100 A131 A130 A430 A140 A133 A440...
  • Page 55: Drum And Tub Assembly

    11-2 . DRU M & TUB ASSEM BLY K123 K350 K360 K143 K610 F140 K411 K611 K410 K115 K141 K110 K117 K111 K140 K571 F315 F310 F465 K142 K572 K190 F463 K570 F464 K122 K125 K516 K130 K320 K530 K121 K510 K512 K344...
  • Page 56: Dispenser Assembly

    11-3. DISPENSER ASSEMB LY F322 F323 F462 F321 Inlet Valve Filter SVC F300 COLD (BLUE ) HOT (ORANGE) F170 F160 F227 F226 F329 F430 F225 F220 F441 F120 HOT (RED) A275 F130 COLD (BLUE) A276 F432...
  • Page 57: Wiring Diagram

    11. Wiring Diagram RD (L1) FUSE FUSE...
  • Page 58 P/No. : MFL68588901...

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Wm4270h a series

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