LG Steam Washer WM0742H series Installation guide

LG TRAINING MANUAL
LG TRAINING MANUAL
Steam Washer WM0742H*A
Fall 2008

Web Site Address Description
LG USA www.lgusa.com USA sales site
Customer Service us.lgservice.com Customer support
GCSC aic.lgservice.com Service center support
Customer Service Academy www.LGCSAcademy.com Technical training
Contact Number Hours of Operation
Customer Service [phone] 24/7 - 365 days a year
Technical Support [phone] 7am-7pm Mon-Fri / Sat 8-2 CST
Parts Sales [phone] 7am-7pm Mon-Sat CST
Training Center [phone] 8am-5pm Mon-Fri CST
Published August 2008 by LG Electronics USA Trainng Center
Copyright © 2008 LG Electronics of Alabama, Inc.
Ph o n e Co n t a C t s :
We b Co n t a C t s :

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IMPORTANT SAFETY NOTICE
The information in this training manual is intended for use by persons possessing an adequate background
in electrical equipment, electronic devices, and mechanical systems. In any attempt to repair a major
appliance, personal injury and property damage can result. The manufacturer or seller maintains no liability
for the interpretation of this information, nor can it assume any liability in conjunction with its use. When
servicing this product, under no circumstances should the original design be modified or altered without
permission from LG Electronics. Unauthorized modifications will not only void the warranty, but may lead
to property damage or user injury. If wires, screws, clips, straps, nuts, or washers used to complete a
ground path are removed for service, they must be returned to their original positions and properly
fastened.
CAUTION
To avoid personal injury, disconnect the power before servicing this product. If electrical power is required
for diagnosis or test purposes, disconnect the power immediately after performing the necessary checks.
Also be aware that many household appliances present a weight hazard. At least two people should be
involved in the installation or servicing of such devices. Failure to consider the weight of an appliance could
result in physical injury.
ESD NOTICE
Some of the electronic components in appliances are electrostatic discharge (ESD) sensitive. ESD can
weaken or damage the electronics in these appliances in a manner that renders them inoperative or
reduces the time until their next failure. Connect an ESD wrist strap to a ground connection point or
unpainted metal in the appliance. Alternatively, you can touch your finger repeatedly to a ground
connection point or unpainted metal in the appliance. Before removing a replacement part from its package,
touch the anti-static bag to a ground connection point or unpainted metal in the appliance. Handle the
electronic control assembly by its edges only. When repackaging a failed electronic control assembly in an
anti-static bag, observe these same precautions.
REGULATORY INFORMATION
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant
to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy, and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful interference to
radio or television reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or more of the following measures: Reorient or
relocate the receiving antenna; Increase the separation between the equipment and the receiver; Connect
the equipment to an outlet on a different circuit than that to which the receiver is connected; or consult
the dealer or an experienced radio/TV technician for help.
DISCLAIMER
The information in this training manual was accurate at the time of publication. Every effort has been made
to ensure accuracy. Updates, changes, etc. are available via GCSC and LGCSacademy. The information in
this manual is intended for persons with adequate backgrounds in electronics, mechanical, and electronic
servicing. The manufacturer and seller are not to be held responsible for any liability incurred from its use.
COMPLIANCE
The responsible party for this device’s compliance is LG Electronics Alabama, Inc.; 201 James Record Road,
Huntsville, AL, 35813.

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WM0742HGA
SAFETY NOTICES (The Small Print Page) 1
Contents 2
Specifications 4
Warranty 5
Features 6
Controls 7
Fuzzy Logic 8
Door Lock and Indicator Lamp 8
Load Sensing Function 9
Water Circulation 10
Parts Identification (Callout) 11
Accessories 12
Installation 13
Shipping Bolts 13
Leveling Feet 13
Connections 14
Water 14
Drain 14
Electrical 14
Pedestal Installation 15
Control Panel 17
Program Chart 18
Service Safety Warnings 18
Cycle and Option Chart 19
Cycle and Option Information 20
Water Temperature Control 25
Wiring Diagram 27
Dispenser 28
Dispenser Hose Connection Chart 30
Direct Drive Motor 31
Disassembly and Repair 32
Block Wiring Diagram 32
Control Panel 33
Top Cover 33
Dispenser 34
Noise Filter (Electronic) 34
Front Cover 35
Door and Hinge 36
Pumps and Filter Housing 37
Wash Heater 38
Foreign Object Removal 38
Water Level Switch 39
Motor 40

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Disassembly and Repair, continued
Tub and Drum 41
Dampers 42
Turbo Steam Generator 43
Removal / Replacement 43
Input Check Valve 44
Water Level Sensor Wiring Diagram 45
Low Water Sensor 46
High Water Sensor 46
Hall Sensor Test, Diagnosis, and Repair 48
Hall Sensor Wiring Diagram 48
Tall Sensor Testing 50
Voltage Testing Hall Sensor at Stator 50
Control Board Testing Location 51
Voltage Testing Hall Sensor at Control Board 52
Test Mode 53
Error Display 54
Error Code Chart 54
Diagnosis and Check List 56
No Power, No Water Input (IE) 56
Door Error (dE), Drain Trouble (OE) 57
Oversudsing, No Softening, Error Codes (PE, FE, tE, and LE) 58
Fault Diagnosis and Troubleshooting 59
No Power 59
Vibration and Noise In Spin Cycle 60
No Water Supply 61
Detergent Fails To Dispense 61
Liquid Detergent / Bleach / Softener Fail To Dispense 62
Heating Without Water 63
Drain Malfunction 63
Wash Heater Malfunction 64
Wash Heater Overrun 64
Circulation Failure 65
Spin (Motor) Malfunction 66
dE Error Code 66
Tips and Tricks 67
Main Board, With Connectors Labeled 68
Exploded Views 69
Parts List 72
Special Tools, With Part Numbers and Photos 75
Serial Number Identification 76
Supplementary Material 77
Service Bulletins 79
Process Technical Information 89

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INTRODUCTION
The WM0742HGA is a top-of-the-line front-loader with the optional cycles of
Allergiene™, Steam, and Tub Clean.
SPECIFICATIONS

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WARRANTY
Warranty statements vary by product. Be sure to check the warranty that was included
with the product because that is the valid warranty. This statement is generic and for
instructional purposes only.

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FEATURES
LARGE CAPACITY
The larger drum (4.2 cu. ft. IEC) allows higher head drop,
greater centrifugal force, and washing of larger and heavier loads
and oversized items (comforters, curtains, blankets, etc.)
There is less wrinkling and tangling of the laundry.
(See BULKY / LARGE, page 21.)
DIRECT DRIVE
The brushless DC motor drives the drum directly without belts,
pulleys, or transmissions. The maximum spin speed of 1,150
RPM extracts more water from the laundry, reducing drying
times.
TILTED DRUM / LARGE DOOR
The tilted drum (10°) and large door opening allow easier
loading and unloading.
STEAM WASHING / STEAMFRESH®
The steam feature works with the recirculating pump to increase
washing performance while maintaining low energy and water
usage.
STEAMFRESH®is not a wash cycle but uses steam to remove
wrinkles from previously laundered dry clothes.
ROLLER JETS and BALLS
The baffles pick up water as the drum turns and allow it to pour
through the clothing as it tumbles. The rollers enhance the
washing performance while maintaining fabric care.
AUTOMATIC LOAD DETECTION
The microprocessor reads the current required to rotate and
stop the drum in order to determine the weight of the load.
See additional information on page 9.

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FEATURES, continued
BUILT-IN HEATER
The internal heater helps maintain the water at
its optimal temperature for selected cycles. The
SANITARY cycle kills most common germs and
bacteria. The ALLERGIENE cycle is not quite as hot but
kills most dust mites and other allergens in laundry.
(See additional information on page 39.)
CHILD LOCK
This allows the user to lock the controls. Children then
cannot play with the buttons and disturb the wash
cycle. (See additional information on page 23.)
CONTROLS
1. Power Button Turns the machine on or off.
2. Cycle/Start Button Starts or pauses the machine.
3. Custom Program Button Sets an often-used program for convenience.
4. Setting Override Buttons Overrides the standard settings for a cycle.
5. Delay Wash Button Sets the delay to have the washer run later.
6. Display Window Shows the estimated remaining time on the cycle.
7. Option Buttons Enables various optional cycles when required.
See additional information on pages 20 ~24 in this training manual.

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FUZZY LOGIC
To get the best washing performance, the user selects one of the standard cycles.
Sensors in the WASHER make an infinitely variable number of adjustments as the cycle
progresses. Adjustments are automatically made for load size, incoming water
temperature, soil level, rinses required, and other variables.
DOOR LOCK
The door has an automatic, electrically operated lock system. When the machine is off or
paused, the door can be opened by pulling it. When the machine is operating, the
electric latch keeps the door closed.
The door cannot be opened:
•When the WASHER is operating
•When the power failed or the washer is unplugged
(until the capacitor discharges and releases the lock)
•When the DOOR LOCK light is on
•When the drum is still turning
DOOR LOCKED LAMP
The DOOR LOCK lamp lights:
•When the WASHER is operating
•When the water level sensor frequency is lower than 22.9 kHz
•When the temperature inside the tub is over 45°C (113°F)

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LOAD SENSING FUNCTION
In order to determine the size and weight of the load, the machine begins each cycle
by tumbling the load a couple of times. It spins up to approximately 120 rpm for
approximately 6 seconds. (Speed and time may vary by model.)
Determining the
size and weight of
the load allows the
controller to
estimate the
amount of water
required to wash
and rinse the load.
The fuzzy logic
within the program
will make numerous
decisions during the
cycle, adding water,
desudsing, and
rinsing as deter-
mined necessary.

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WATER CIRCULATION
The recirculation pump circulates the water during most of the cycle. During the WASH
cycle, it runs continuously for the first 3 minutes and then intermittently throughout the
cycle. During the RINSE cycle, it runs continuously as soon as the appropriate amount of
rinse water has been added. This recirculated water enters the drum at the top of the
door at a small shower head. This spray not only keeps the window and gasket clean, it
allows the clothes to be soaked with detergent or rinse water more quickly and can be
used to control an oversudsing event.
The recirculation pump is separate from
the drain pump, but they are attached
to opposite sides of the filter housing.
The steam is not pumped; it comes into
the washer drum under its own
pressure. When steam or the sanitary
cycle is used, the door will remain
locked until the laundry has cooled to a
safe temperature.
The pumps and filter are located at the
bottom left front corner. The filter can
be unscrewed, cleaned, and replaced.
Use the small drain hose to evacuate
the water remaining in the bottom of
the tub before removing the filter.
The drain pump is on the left and
exhausts the water via the gray
corrugated hose.
The recirculating pump is on the right
and recirculates water from the tub to
the shower spray at the top of the door
gasket via the smaller black hose.
The filter is not a lint filter in the usual
sense of the word. Its function is to
keep debris out of the pump impellers.

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PARTS IDENTIFICATION
The air vent on the back of the machine must be left open and clear at all times.
If the washer and dryer are installed in a closet or closed laundry alcove, there must be
sufficient clearance and ventilation. The closet should have a full louvered door with at
least 800 square inches (0.5 m2) of open area for ventilation.
The washer requires a space of at least 1 inch (2.5 cm) between the wall and the
machine on each side and at least 4 inches (10 cm) between the back of the washer and
the wall. Additional space may be needed for servicing.

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ACCESSORIES
The washer comes with the two input hoses. The blue stripe is for cold water and the red
stripe is for hot water. The hoses are not mechanically identical. It is critical to the
performance of the washer to have the hot and cold hoses connected correctly. The hot
hose is a thicker material suitable for higher temperatures and pressure.
The wrench is used to remove (and replace) the shipping bolts and to adjust the leveling
feet. Be sure to leave it and encourage the customer to retain the wrench, the four
shipping bolts, and the manual in a safe place in the event the washer requires service or
the customer moves.
The shipping bolts MUST BE REMOVED before operating the washer. (See page 13.)
The wrench, shipping bolt hole covers,
drain hose tie down strap, and a sample
packet of detergent are included in a
packet shipped inside the washer.
See page 29 concerning detergent usage.

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INSTALLATION
REMOVE THE SHIPPING BOLTS. LEAVE THEM WITH THE CUSTOMER.
The lower right bolt is equipped with a clip that secures the cord so it is impossible to
plug in the machine without removing the bolt. The cord is further secured by an
adhesive sticker which must be broken to free the cord to plug in the machine.
INSTALL THE WASHER ON A FIRM, FLAT SURFACE.
ADJUST THE FEET TO BE LEVEL. LOCK THE ADJUSTERS IN PLACE.

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CONNECTIONS
WATER
Be sure the rubber washer is inside the hose end. Attach the hoses to the washer (red is
HOT, blue is COLD). Tighten them firmly but don’t strip the plastic threads on the
washer connections. The HOT hose is thicker and has a higher temperature rating and
burst strength.
DRAIN
The drain pipe should be firmly attached to the standpipe or the laundry tub or sink
where it drains. The pump has sufficient power to cause the pipe to move around when
the water is expelled. The pump can lift the drain water a maximum of 96 inches (2.4 m),
but there is no minimum height requirement. The vacuum breaker in the drain line will
prevent drainage by gravity or siphoning. The hose can lay flat into a floor drain as long
as the end of it is not submerged.
ELECTRICAL
The steam washer requires a 120 VAC, 60 Hz., dedicated, 20-amp circuit.

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INSTALLATION (PEDESTAL KIT)
This procedure covers installing and leveling the 7½” and 13” pedestals for 27” washers,
dryers, and combos. If the products are stacked, the washer must be below the dryer,
and only one pedestal is required.
Remove the pedestal, installation hardware,
and instructions form the shipping carton.
Set the pedestal as close to the installation
position as possible.
Level the pedestal on a flat, solid floor
before proceeding. Lock down the rear
adjusters but leave the front ones free
for now.
Note which holes are for the washer and
which are for the dryer. If you are stacking
the appliances, the washer must be on the
bottom.
Remove the protective paper from the
adhesive surface of the bracket. Be
particularly careful, because when the
adhesive makes contact, no adjustment is
possible.

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PEDESTAL, continued
Depending upon the model, your pedestal
may have straight or curved brackets. The
curved ones are to be used on the rear
positions when mounting a dryer to a
pedestal, but can also be used in any other
position on the pedestal.
Holding the exposed adhesive away from
the appliance, insert the screws and get
them started. Then press the brackets to
the appliance and tighten all the screws.
Rub the bracket from side to side to ensure
a complete bond.
Use the wrench to turn each leg of the
appliance approximately ¼turn to put a
little pressure between the appliance and
the pedestal. This will eliminate any
rattles and vibration.
It is usually easier to set the pedestal and
washer into place and connect the water
and drain hoses before placing the dryer
on top of them.

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CONTROL PANEL
The control panel is located on the front of the Washer. All options are available from
the control panel.
The ESTIMATED TIME remaining
is shown in the window. This may
fluctuate during the cycle because
the washer will make numerous
adjustments based on fuzzy logic
and the data supplied by various
sensors in the machine.
CHILD LOCK will render every
button except the POWER button.
CL blinks in the display when the
CHILD LOCK is engaged. To turn
off the machine if it is running with
CHILD LOCK engaged, you must
first disengage CHILD LOCK and
then press POWER to turn it off.
The START/PAUSE button is
incorporated into the CYCLE
SELECTOR knob. Twist the knob
to select a cycle; push it to push it
to START or PAUSE the cycle.
The CUSTOM PROGRAM button
allows the user to set all the
desired options on a cycle
commonly used so that cycle is
then available at the touch of a
single button.
The DOOR LOCKED light
indicates that the door lock is
engaged.

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PROGRAM CHART
This chart shows the components and their times of operation in the various wash cycles.
The time estimates shown here are for the basic cycles before the fuzzy logic
adjustments are made. See the cycle and option chart on the following page.
BEFORE PERFORMING SERVICE
•Be careful to avoid electric shock when disconnecting parts for troubleshooting.
•Most terminals in the steam washer have 120 Volts AC or DC on them,
sometimes even when the washer is off.
•The steam generator operates at a high temperature. Be careful when servicing it.
It can be drained in place by removing the drain cap, but have a hose or a big
towel ready to soak up the spillage.