LG WM4370H A Series User manual

WASHING MACHINE
SERVICE MANUAL
CAUTION
READ THIS MANUAL CAREFULLY TO DIAGNOSE
PROBLEMS CORRECTLY BEFORE SERVICING THE UNIT.
MODEL: WM4370H*A
Website : http://biz.lgservice.com
1
Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means),
publication, modification, copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you
have obtained the prior written consent of the LG Electronics entity from which you received this Service
Manual. The material covered by this prohibition includes, without limitation, any text, graphics or logos in this
Service Manual.
Copyright © 2016 ~ 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

CONTENTS
1. Specifications .................................................................................................................................. 3
2. Features and Technical Explanation ............................................................................................ 4-6
3. Parts Identification ........................................................................................................................... 7
4. Installation and Test ................................................................................................................... 8-10
5. 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
6. Test Mode ...................................................................................................................................... 18
6-1. Safety Caution ....................................................................................................................... 18
6-2. Load Test Mode ..................................................................................................................... 18
6-3. How To Read the Display in Load Test Mode ........................................................................ 18
7. Troubleshooting ............................................................................................................................ 19
7-1. Safety Caution ....................................................................................................................... 19
7-2. Error Mode Summary ....................................................................................................... 19-20
7-3. Troubleshooting With Error ............................................................................................... 21-27
7-5. Before using the Tag On function .......................................................................................... 33
7-4. Troubleshooting Else ........................................................................................................ 28-32
8. Component Testing Information .................................................................................................... 34
8-1. Filter Assembly (Line Filter) ................................................................................................... 34
8-2. Door Look Switch Assembly ............................................................................................. 35-36
8-3. Stator Assembly ................................................................................................................ 37-39
8-4. Pump Motor Assembly ........................................................................................................... 40
8-5. Inlet Valve Assembly .............................................................................................................. 41
8-6. Heater Assembly .................................................................................................................... 42
8-7. Thermistor Assembly ........................................................................................................ 43-44
9. Disassembly Instructions ........................................................................................................... 45-53
10. Exploded View ......................................................................................................................... 54-56
11. Wiring Diagram ............................................................................................................................. 57
10-1. Cabinet and Control Panel Assembly ................................................................................... 54
10-2. Drum and Tub Assembly ...................................................................................................... 55
10-3. Dispenser Assembly ............................................................................................................. 56
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1.SPECIFICATIONS
WM4370H*AI T E M
COLOR
POWER SUPPLY
PRODUCT WEIGHT
CYCLES
SERUTAREPMETESNIR/HSAW
SPIN SPEEDS
OPTIONS
NOITALUCRICRETAW
OPERATIONAL WATER PRESSURE
CONTROL TYPE
WASH CAPACITY [cu.ft. ]
DIMENSIONS
DELAY WASH
DOOR TYPE
WATER LEVEL
LAUNDRY LOAD SENSING
ERROR DIAGNOSIS
AUTO POWER OFF
CHILD LOCK
STEAM
ELECTRIC POWER
CONSUMPTION
REVOLUTION
SPEED
WASHING
DRAIN MOTOR
WASH HEATER
WASH
SPIN
14
5
5
Steam,PreWash, Delay Wash, CustomPG M,Fresh Care,PG M Save,
TurboWash, Cold Wash,Ext ra Rinse, Rinse+Spin, DrumLight
Incorporated
20 – 120 PSI(138 – 827kPa)
Electronic
(4.5 DOE)
27”(W) X 29
3/4
”(D) X 38
11/16
”(H), 51”(D, door open)
up to 19 hours
CHROME
10 steps (by sensor)
Incorporated
Incorporated
Incorporated
Incorporated
Incorporated
240 W
80 W
1200 W
46 rpm
0-1,300 rpm
Blue White, VCM, Black STS
zH06,V021CA
202.8lb (92kg)
yrtsudnillaoterehda,snosrepotyrujnifoksirehtecuderoT
recommen ded safetyproc edures including the use o gnolf
follawollofoteruliaF.sessalgytefasdnasevolgdeveels
the safety w arnings in this manual could result in pro perty
.htaedrosnosrepotyrujni,egamad
WARNING
SMART NFC (Tag On function)
Smart Diagnosis function (3.0)
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2. FEATURES & TECHNICAL EXPLANATION
2-1. FEATURES
Ultra Capacity
The larger drum enables not just higher head drop and stronger centrifugal force,
but also less tangling and wrinkling of the laundry. Heavier loads, such as king size
comforters, blankets, and curtains, can be washed.
Direct Drive System
The advanced brushless DC motor directly drives the drum without belt and pulley.
Tilted Drum and Extra Large Door Opening
Tilted drum and extra large opening make it possible to load and unload clothing
more easily.
Steam Washing
Steam washing features upgraded washing performance with low energy and water
consumption.
Automatic Wash Load Detection
Automatically detects the load and optimizes the washing time.
Built-in Heater
Internal heater helps to maintain water temperature at its optimum level for selected
cycles.
Child Lock
The child lock prevents children from pressing any button to change the settings
during operation.
SMART DIAGNOSIS TM
Should you experience any technical difficulty with your washing machine, is capable
of producing multiple distinct different motions for optimal washing performance
with very little noise and vibration. 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.
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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.
2-3. WATER LEVEL CONTROL
This model incorporates a pressure sensor which can sense the water level in the tub.
The water supply is stopped when the water level reaches the preset level, the washing
program then proceeds.
Spinning does not proceed until the water in the tub drains to a certain level.
water
temperature
washing time
rinsing time
the best
washing
performance
spin rhythm, time
load
size
NEURO-
FUZZY
selected
washing
temperature
SENSING EFFECT PROCESSING DETERMINATION
The door can be opened by pulling the door handle whenever washer is not in operation.
When the cycle is completed, the DOOR LOCKED light will turn off.
If a power failure has occurred while in operation, the door will unlock after 5 minutes.
Clicking sounds can be heard when the door is locked/unlocked.
2-4. DOOR CONTROL
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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. DOOR LOCKED LAMP LIGHTS
When the frequency of water level is lower than 22.9 kHz.
(It can be canceled when the frequency is more than 23.8 kHz.)
When the temperature inside the tub is higher than 45°C and water level is not 25.5 kHz.
(It can be canceled when the water level is 25.5 kHz or the temperature inside the tub is lower than 40°C.)
2-7. CHILD LOCK
Use this option to prevent unwanted use of the washer. Press and hold Pre Wash button for 3
seconds to lock/unlock control.
When childlock is set, CHILD LOCK lights and all buttons are disabled except the POWER
button. You can lock the controls of the washer while washing.
CHILD LOCK lasts after the end of cycle. If you want to deactivate this function,
Press and hold thePre Wash button for 3 seconds.
2-8. WATER CIRCULATION
When washing and rinsing function of shower at the upper part of Gasket.
When washing, it continuously operates for 3 minutes and intermittently.
When rinsing, it continuously operates after completion of water supply.
2-9. STEAM
For tough stained clothes, sick room linens, or baby clothes.
Steam Wash is available with Sanitary, Bulk/Large, Perm. Press, Cotton/Normalcycles.
This option features upgraded washing performance with low energy and water consumption.
Do not load delicates such as wool, silk, and easily discolored clothes.
2-10. NFC (Tag On Function)
The Tag On function can only be used with smart phones equipped
with the NFC function and based on the Android operating system (OS).
Position your smart phone so that the NFC antennaon the backof
your smart phone matches the position ofthe Tag On icon on the appliance.
NFC reading performance of your smart phone must be higher than
a certain level for using this function.
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3. PARTS IDENTIFICATION
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.
The images in this guide may be different from the actual components and accessories, and are subject to change by
the manufacturer without prior notice for product improvement purposes.
Parts and Accessories
Parts
Pedestal
(sold separately)
Stacking Kit
(sold separately)
Accessories
Hot/cold water hoses Non-skid pads Caps for covering
shipping bolt holes
Wrench Tie strap Elbow bracket
(for securing drain hose)
Water inlets
Shipping
bolts
Power cord
Drain hose
INCLUDED Accessories OPTIONAL Accessories
Detergent
dispenser
drawer
(See page 20)
Door
Magnet Door
Plunger
(see page 3)
Control panel
(See page 9)
Door
seal
Water
circulation
and steam
nozzles
Tub
Leveling
feet
Drain pump filter cover
Drain pump filter
Drain hose
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1
2
3
4
5
6
7
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 VAC, remove the transit bolts, level the washer, etc.)
Check with the troubleshooting guide.
Plan your service method by referring to the disassembly instructions.
Service the unit.
After servicing, operate the appliance to see whether it functions correctly.
STANDARD INSTALLATION
The appliance should be installed as follows:
Remove the 4 shipping bolts
with the supplied wrench.
Remove the lower bolts fist.
It is easier that way.
Keep the shipping bolts and
spanner for future use.
Insert the 4 caps (provided)
into the hole.
Turn clockwise to raise;
counterclockwise to lower.
Turn the leveling feet to
adjust the appliance.
REMOVE THE SHIPPING
BOLTS
INSTALL THE APPLIANCE
ON A FLAT AND FIRM SURFACE
ADJUST THE
LEVELING
4. INSTALLATION & TEST
Keeping
Lower
Higher
8
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CONNECT POWER PLUG
•Connect the power plug to the wall outlet.
•Avoid connecting several electric devices,
as doing so may cause a fire.
Verify that the rubber washer is inside of the
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.
HOW TO CONNECT THE INLET HOSE
CONNECT THE DRAIN HOSE
The end of the drain hose should be placed less than 96” from the floor.
•Make sure that the hose is not twisted. •Avoid submerging the end of the hose.
Hot Cold
9
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7TEST OPERATION
1Preparation for
washing.
•Connect the power plug to the
outlet.
•Connect the inlet hoses.
2Press the POWER button. 3Press the START/PAUSE
button.
•Listen for a click to determine if the
door has locked.
6Check the water heating
function.
•Press the Soil Level button
and the present temperature will
be displayed.
•Check if the drum rotates
clockwise and counterclockwise.
5Check the automatic reverse
rotation.
4Check the water supply.
•Check if water is supplied through
the detergent dispenser.
7Check the drain and spin
functions.
•Power off and the power on.
•Press the SPIN SPEED button.
•Press the START/PAUSE button.
•Check the spin and drain functions.
•Listen for a click to determine if the
door is unlocking.
8Press the START/PAUSE
button.
9Water removal
•If SERVICE is needed during
water by pulling out the hose cap.
10
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WM4370H*A
5. OPERATION
5-1. CONTROL PANEL FEATURES
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reserved. Only training and service purposes.

Power Button
•Use this button to turn the
power On/Off.
Status Indicator
•It shows elapsed time of the cycle the washer is
operating.
Cycle Selector Knob
•Rotate the Cycle selector knob to select the cycle
designed for different types of fabric and soil
levels.
Start/Pause
•Use this button to
Start/Stop the washer.
12
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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
start of the wash cycle.
ADD GARMESNTS : Use this function to add garments or remove foreign objects like coins or keys after
the cycle has started
TURBO WASH : Use This option save time.
COLDWASH™ : Use this function to wash without hot water and heating.
EXTRA RINSE : This option will add an extra rinse cycle to the selected cycle.
RINSE+SPIN : Use this option to rinse detergent from load.
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.
Wash Temp., Spin speed, Soil Level, Signal Button
•Select a water temperature based on the type of load you are washing.
•To change the spin speed, press the Spin Speed button repeatedly to cycle through available options.
•To change the soil level, press the Soil Level button repeatedly until the desired setting is on.
•Press repeatedly to adjust the volume of the Signal.
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5-2. Cycle Guide
The cycle guide below shows the options and recommended fabric types for each cycle.
●
= Available option
CYCLE FABRIC TYPE
BASIC OPTION (
=DEFAULT) ADDITIONAL OPTIONS
Wash
Temp.
Spin
Speed
Soil
Level
Pre
Wash
Extra
Rinse Steam Cold
Wash™
Turbo
Wash™
Tub CleanThis cycle is
designed to remove
a mildewyor musty
smell.

Allergiene™ Cotton, underwear,
pillow covers,
bed sheets, baby
wear
Extra High
High★
Medium
Low
No Spin
  
Sanitary Heavily soiled
underwear, work
clothes, diapers,
etc.
Extra Hot
★Extra High
High★
Medium
Low
No Spin
Heavy
▼
Normal ★
▼
Light
   
Bright
Whites
™
White Fabrics Hot★
Warm
Cold
Tap Cold
Extra High
High★
Medium
Low
No Spin
Heavy
▼
Normal ★
▼
Light
   
Bulky/Large Large items such as
blankets and
comforters
Hot
Warm ★
Cold
Tap Cold
Medium ★
Low
No Spin
Heavy
▼
Normal ★
▼
Light

Cotton/
Normal Cotton, linen, towels, shirts,
sheets, jeans,
mixed loads
Extra Hot
Hot
Warm ★
Cold
Tap Cold
Extra High
High★
Medium
Low
Heavy
▼
Normal ★
▼
Light

Heavy Duty Heavy soiled Cotton
FabricsHot Warm

Cold
Tap Cold
Extra High★
High
Medium
Low
Heavy★
▼
Normal
▼
Light

Perm.Press Dress shirts/pants,
wrinkle-free
clothing, poly/
cotton blend
clothing,
tablecloths
Hot
Warm ★
Cold
Tap Cold
High
Medium ★
Low
Heavy
▼
Normal ★
▼
Light
   
Hand Wash/
WoolItems labeled “hand-washable” Warm ★
Cold
Tap Cold
Low★
No Spin Normal ★
▼
Light

Delicates Dress shirts/
blouses,
nylons, sheer or
lacy garments
Warm
Cold★
Tap Cold
Medium ★
Low
No Spin
Heavy
▼
Normal ★
▼
Light
  
Towels Towels Hot
Warm ★
Cold
Tap Cold
Extra High★
High
Medium
Low
No Spin
Heavy
▼
Normal ★
▼
Light
   
Speed Wash Lightly soiled
clothing
and small loads
Hot★
Warm
Cold
Tap Cold
Extra High★
High
Medium
Low
No Spin
Heavy
▼
Normal
▼
Light★
  
Drain+Spin Drain, Spin Only Extra High
High
★
Medium
Low
No Spin
-Cycle time depends on type and amount of load and detergent,water pressure and chosen additional
options.
-If the Turbo Wash™ option is on, you cannot select “No Spin” as your Spin Speed.
(If the Turbo Wash™ option is off, you can select “No Spin” as your Spin Speed.)
- Do not load more than 22 lb. (10 kg) in the washer. (1 thick, dry bath towel = 1 lb.)
Do not use the Sanitary cycle with more than 10 lb. (4.5 kg) of laundry.
Do not use the Hand Wash/Wool cycle with more than 8 lb. (3.6 kg) of laundry.
-Do not overload the Bulky/Large cycle. If the washer does not function properly, manually redistribute the
load or wash one item at a time.
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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. Press and hold the PRE WASH button for 3
seconds to activate or deactivate The child lock function The child lock indicator will be
shown in the display. And all buttons are disabled except the ON/OFF button
NOTE: CHILD LOCK lasts after the end of cycle. If you want to deactivate this function,
Press and hold the PRE WASH button for 3 seconds.
15
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5-4. Explanation of each process
No. noitanalpxEssecorP
1. Stay •Electrical power is supplied.
•Washer is ready to work and the micom is in the active mode.
2. Water
supply
•After loading laundry and selecting a course and a cycle, water is
supplied and drum rotates.
•When a user selects Pre-wash course, water is supplied through pre
wash valve.
3.
Soaking
and washing
laundry
•To get laundry wet, drum rotates clockwise and counterclockwise.
•If water amount is insufficient at this time, the Inlet valve will supply
water again.
4.
Heating and
washing
•The heater heats the water in drum to the selected water temperature
and drum rotates for washing.
5.
6.
Washing
and heating
/ washing
•When the water temperature reaches to the selected temperature,
the heating stops and only the drum rotates.
•If water temperature becomes lower than selected because of
re-supplied water, the heating starts again.
7. Washing •Fuzzy logic decides washing time according to the laundry load, water
temperature, and other factors.
8. Drainage •A pump motor drains the water from the drum.
•After sensing drained water amount by water level frequency, spin starts.
•When a heating course is selected, stay cooling process is performed to
decrease the water temperature gradually to prevent laundry from being
damaged and for safety reasons.
9. Untangling
(Sensing
eccent-
ricity)
•It balances laundry load and senses the eccentricity of the load, to only
allow spinning without vibration.
•If the eccentricity is worse than the allowed level, it repeats the
disentangling process. When the repeated time is more than allowed
level, it displays UE.
•If the eccentricity is good, the intermittent spin starts.
•During this process, the drain pump works for drainage intermittently.
16
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No. noitanalpxEssecorP
10 Intermittent
spin
•To reach the correct set speed, the motor rotates clockwise and
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.
11 Rinse
spin
•In this process, the remaining water during washing process is
extracted and the selected speed is kept.
•Removing suds process is in active mode at this cycle.
12 Remaining
spin
•After spin finishes, the drum rotates by remaining spin power until it
stops. Motor power is off.
•This process is overlapped with next process.
13 Rinse water
supply
•Water supply for rinse process.
14 Rinse •Rinsing process.
15 Last
drainage
•After spin finishes and power is not supplied to motor, the drum
rotates by remaining spin power.
•If rinse hold is selected, the drainage is not proceeded after rinse
finishes.
16 Disentangling •The same as item 9.
17
Intermittent spin
•The same as item 10.
18
19
20
21
22
Main spin1 •The same as item 11.
Main spin2•At the end of a main spin, the spin speed will reach the selected rpm.
Remaining spin•The same withitem 12.
Disentangling•After spin finishes, disentangling starts to remove unbalanced
laundry.
End •After ‘end’ signal is displayed, it stays for 8 seconds and power is
automatically turned off. (Auto type door switch)
•After door switch is off, end signal is displayed in the case of
manual type and it takes around 2 minute to turn off door switch.
17
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6. TEST MODE
SPIN SPEED SOIL LEVEL
WASH/RINSE DELAY WASH
Turns on all lamps and locks the door.
6-1.
6-2.
7
6-3.
18
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7. TROUBLESHOOTING
7-1.
7-2.
19
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LOCKED MOTOR
ERROR
EEPROM ERROR
The connector (3-pin, male, white) in the MOTOR
HARNESS is not connecte d to the c onnector (3-pi n,
female, white) of STATOR ASSEMBLY.
The electric con tact 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.
The MOTOR HARNESS between the STATOR
ASSEMBLY and MAIN PWB ASSEMBLY is cut
(open circuited).
The NFC HARNESS between the NFC PCB
ASSEMBLY and DISPLAY PCB ASSEMBLY is
cut or not connected(open circuited).
The NFC PCB ASSEMBLY is bad or out of
order(short circuited).
The NFC EEPROM is out of order.
※ nC is displayed only in the first screen of
the Test Mode.
NFC version is not matched.
→ It needs to be exchanged.
※ nU is displayed only in the first screen of
the Test Mode.
8
EEPROM is out of order.
Displayed only when the START/PAUSE button is
first pressed in the Load Test Mode.
9
machine is working, the power is supplied rapidly.
10
NFC MODULE
ERROR
POWER FAILURE
NFC VERSION
ERROR
11
12
ERROR SYMPTOM CAUSE
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