LG LWD3081ST - Double Electric Oven Installation guide

LWD3081ST TRAINING MANUAL
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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 electronics 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.

WALL OVEN TRAINING MANUAL
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LWD3081ST (Double Wall Oven)
The Small Print Page 1
Contents 2
Introduction 4
Special Warnings and Information 5
Specifications 6
Warranty 7
Controls 8
Component Location Chart 10
Replacing the Control Panel and Related Parts 11
Controller LVT (Low Voltage Transformer) 12
Relay PCB 13
Door Locking Mechanism 14
Manual Unlocking Procedure 15
Halogen Lamp LVT (Low Voltage Transformer) Replacement 15
Surge Filter 16
Replacing Oven Cavity Components 17
Broil Element 17
Convection Element 18
Convection Fan Blade 18
Halogen Lamps 19
Oven Sensor 19
Replacing Other Electrical Components 20
Vent (Cooling Fan Blower) Motors 21
Thermal Limiters 21
Door Switch 22
Upper Oven Repair 23
Back Cover 24
Convection Fan Motor 25
Hidden Bake Element 26
Lower Oven Repair 28
Oven Doors 30
Repairing the Oven Door Handle and Glass 31
Replacing the Door Gasket 33
Component Tests 34
Convection Fan Motor 34
Door Locking Motor 34
Door Locking Microswitch 35
Low Voltage Transformer (Controller) 35
Low Voltage Transformer (Halogen Lamps) 35
Oven Thermistor 36
Door Switch 36
Halogen Lamps 36

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LWD3081ST (Double Wall Oven), continued
Component Tests (continued)
Broil Element 37
Bake Element 37
Convection Element 37
Vent Motor 38
Test Mode 39
Error Codes (F-Codes) 40
Diagnostic Flow Charts 41
Dead Oven 41
Oven Does Not Heat (F-9 or F-19 Error Codes) 46
Control Panel Failure (F-3 Error Code) 50
Lock System Failure (F-10 and F-20 Error Codes) 51
Oven Thermistor Failure (F-1, F-2, F-4, and F-5 Error Codes) 53
Oven Too Hot (F-6 and F-16 Error Codes) 54
Communication Error (F-10 Error Code) 55
Schematic 56
Strip Circuits 57
Full Broil Mode 57
Center Broil Mode 58
Crisp Convection Mode 59
Convection Bake and Convection Roast Modes 60
Bake and Roast Modes 61
Self Clean Mode 62
Warm and Proof Modes 63
Serial Number Information 64
Exploded Views 65
Component Parts (Controller, door, oven cavity) 65
Controller 66
Doors 66
Upper Oven 67
Lower Oven 68
Racks, Trim, and Covers 69
Parts List 70
Supplementary Information 74
Ver. 1.3 090213

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INTRODUCTION
The LWD3081ST built-in double wall oven, and its smaller sibling, the single oven, are
LG’s recent entries in the appliance arena. The double oven is actually two single ovens
bolted together, with the chief difference being that the lower oven does not have the
accessory probe socket or the healthy roast feature.
The model and serial numbers are on the ID sticker mounted under the control panel.
Open the door (top door on double ovens) and look under the panel to see it.
The tech sheet is located inside the control panel area. Pull the oven out of its cabinetry
slightly and take the cover off the control area.
WARNING! ELECTRIC SHOCK HAZARD
The oven must be disconnected from the power supply while repairs,
replacements, and adjustments are carried out. Failure to do so can result
in electric shock or death by electrocution.
WARNING! CUT HAZARD
Use extreme caution when handling the metal parts of the oven. The
edges can be extremely sharp. Wearing service gloves is recommended.

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SPECIAL WARNINGS and INFORMATION
Do not put aluminum foil where it touches
the sides, back, or bottom of the oven. It
will melt and destroy the finish of the oven.
This damage is not repairable.
The metal trim piece must be installed
correctly at the bottom of the oven. This
trim piece deflects the cooling air flow and
must be in place.
The convection fan is in the back of the
oven. It circulates the hot air in the oven
for faster and more even cooking.
All functions are available via the touchpad
menus.
The menus are displayed in the window of
the control panel and change as necessary.

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SPECIFICATIONS

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WARRANTY
This warranty sheet is provided for instructional purposes only. Warranties vary from
time to time, model to model, year to year, and country to country. Refer to the
warranty certificate that was provided with your customer’s product for accurate
warranty coverage information.

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CONTROLS
The full operating instructions are included in the owner’s manual. This section is
designed to provide enough information for the servicer to diagnose and repair any
issues with the oven.
The control panel is a capacitance glass touch panel. There are no moving parts; the user
merely touches the panel at the option to be selected. Occasionally, people with poor
circulation or small, thin fingers may experience some difficulty making the panel sense
their presence. If they use their thumbs, this issue is usually alleviated.
Read all instructions carefully before operating the oven.
In the event of a power failure, the clock will flash and a PF error code will show in the
display. Reset the time. If the oven was set for a timed operation when the power failure
occurred, the clock and all programmed functions must be reset.
1Upper oven light Turns the upper oven lights on and off
2Lower oven light Turns the lower oven lights on and off
3 Upper oven Activates the controls for the upper oven
4Lower oven Activates the controls for the lower oven
5 Start Starts all oven features
6Timer (ON / OFF) Sets or cancels the timer
7Upper CLEAR / OFF Turns the upper oven OFF or cancels its setting
8 Lower CLEAR / OFF Turns the lower oven OFF or cancels its setting
9Touch Screen Shows the time of day, menus, oven temperatures and
cycles, timer, and automatic functions. This panel will go
into a sleep mode if there is no activity for 10 minutes. To
wake it, touch it and make your selections.
Continued on next page.

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9Touch Screen Shows the time of day, menus, oven temperatures and
cycles, timer, and automatic functions. This panel will go
into a sleep mode if there is no activity for 10 minutes. To
wake it, touch it and make your selections.
10 Bake Selects the normal bake mode
11 Broil Selects the normal broil mode
12 Roast Selects the normal roast mode
13 Convection Bake Selects the convection bake mode
14 Crisp Convection Selects the crisp convection mode
15 Convection Roast Selects the convection roast mode
16 Recipe Bank Contains 100 recipes designed especially for this oven
17 Proof / Warm For proofing (raising) bread dough or keeping food warm
18 Healthier Roast Selects the healthier roast mode
19 My Menu Stores and recalls the customer’s ten favorite cooking
sequences
20 Set up Sets and changes special settings, including time and
temperature adjustments
21 Self Clean Sets a self-cleaning cycle
ERROR CODES
See the error code chart on page 40. If there is an error code, ask the customer to make
a note of the code before pressing CLEAR / OFF. Allow the oven to cool for at least an
hour, and then try the cooking cycle again. If the error code repeats itself, have the
customer disconnect the power and call for service.

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COMPONENT LOCATIONS
The drawing shows the relative positions of most parts considered to be serviceable.
For most repairs, the oven will NOT need to be removed from the cabinetry for service.
As the double oven weighs over 250 pounds (157 kg), two people will needed for
removal and replacement. An alternative is to use an oven dolly. Additionally, caution
must be exercised to avoid damaging the oven, the cabinetry, and the floor when
servicing the oven. Most service operations can be performed without removing the oven.
These will be listed in the service procedures contained within this manual.
WARNING! ELECTRIC SHOCK HAZARD
The oven must be disconnected from the power supply while repairs,
replacements, and adjustments are carried out. Failure to do so can result
in electric shock or death by electrocution.

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REPLACING the CONTROL PANEL and RELATED COMPONENTS
Turn off the electric power to the oven.
Open the upper oven door.
Remove three screws from the bottom
edge of the control panel.
Close the upper oven door.
Lift the control panel off the guide hooks
and top trim.
Tilt the control panel down.
It hinges in the slots on the main body of
the oven and will hang there in the service
position.
Disconnect the 8 plastic connectors at the
main board to allow removal of the control
panel from the oven.
Connectors include CN 01, CN 02,
CN 03, CN 04, CN 05, CN 08, CN 11,
and CN 12.
Remove the control panel and set it aside
on a soft cloth to prevent damage and
scratches.

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After the control panel is removed, the
interior of the parts area is visible.
The following parts can be removed
without removing the oven from the
cabinetry.
Controller LVT (Low Voltage Transformer),
relay PCB, door lock motor, halogen lamp
LVT, and surge filter.
Controller LVT (Low Voltage Transformer)
Remove the screw that secures the
transformer base to the bracket.
Remove the entire bracket and transformer
as a unit.

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RELAY PCB
To remove the relay PCB, remove the
screw that secures the board to the control
area.
Slide the board out from the control area.
Disconnect all thirteen plastic connectors
from the relay board. Connectors include
CN 01, CN 02, CN 03, CN 04, BL, YL,
WH, VI, VI (again), RD, YL, RY 19, and
RY 20.

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DOOR LOCKING MECHANISM
The door lock assembly is mounted on the
top of each oven. It activates during a self-
clean cycle and will not open again until
the internal oven temperature drops below
500°F (260°C).
To remove the door lock assembly, open
the oven door.
Remove the two screws that secure the
lock assembly to the oven front.
Lift the door lock motor out and unplug
the electrical connector.
If replacing the lower oven door lock, you
must separate the ovens to allow access.
A cam on the lock motor operates a
microswitch attached to the lock
mechanism which reports its position to
the main board.
The main board will not allow the self-clean
cycle to operate unless the lock is engaged.

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MANUAL UNLOCK PROCEDURE
If necessary, the door lock is spring-loaded
and can be released manually.
Use an L-shaped object, like an Allen
wrench. Reach between the door and the
control panel. Grasp the hook on the
motor and pull it toward the left.
When the hook is pulled aside, you can
open the oven door. While this condition
persists, consider the oven out of service
and do not attempt to cook in it.
Refer to pages 14 and 51 for the
procedure to test and replace the lock
motor mechanism. An alternate method is
to disconnect the unlock motor from the
oven wiring and apply 120 VAC to it. If the
motor will operate, allow it to rotate to the
unlock position. This will also let you know
the motor is good and to look at the wiring
and the main control board.
HALOGEN LAMP LOW VOLTAGE TRANSFORMER (LVT) REPLACEMENT
Disconnect the 5 connectors on the lamp
transformer. It may be easier to remove the
transformer before separating the
connectors.
Remove the screw that secures the
transformer base to the bracket.
Remove the entire bracket and transformer
as a unit. The back end of the transformer
slides into brackets stamped into the base.
Pay attention to the sticker on the top of
the transformer. It shows which wires are
connected to which terminals. A mistake
here will destroy the transformer and the
control boards.

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SURGE FILTER REPLACEMENT
To replace the surge filter, remove it from
the oven.
Remove one screw that attaches the
bracket and filter to the back of the control
area.
Remove the screw and ground wire.
Be sure to pull the bracket out toward the
left to clear the bracket at the top right
corner.
Disconnect the two leads and remove the
board from the oven.

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REPLACING OVEN CAVITY COMPONENTS
WARNING! Disconnect the power before
working on the oven.
WARNING! Many of the metal panels have
sharp edges. We recommend wearing
assembly gloves for safety.
The broil element, convection element,
convection fan blade, oven thermistor, and
halogen lamps can be serviced without
disassembling the oven.
BROIL ELEMENT
Remove the four screws from the front and
rear brackets.
(Two on the rear bracket; one on each of
the two front brackets.)
Pull the element forward to access the
terminals and disconnect the wires. Be
careful to avoid damaging the wires on the
edges when you pull them through the
hole.
Some terminals may be equipped with a
release tab which must be pressed to
release the connector.

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CONVECTION ELEMENT
Remove the four screws that secure the
convection fan cover. (This cover takes up
most of the back of the oven cavity.)
Take the cover out of the oven cavity.
WARNING! Be careful to avoid bending or
damaging the fan blade.
Remove the four screws that secure the
convection element.
The element is fragile. Handle it carefully to
avoid damage or breakage.
Pull the element forward into the oven
cavity. Be careful to avoid damaging the
wires on the edges when you pull them
through the hole.
Some terminals may be equipped with a
release tab which must be pressed to
release the connector.
CONVECTION FAN BLADE
Remove the nut securing the fan blade.
(It is a left-hand thread.)
Pull the fan blade off the shaft. Do not lose
the bushing (spacer) or washer.
Be careful to avoid bending the fan blade.

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HALOGEN LAMPS
There are three halogen lamps in the oven.
(Three in each oven for the double oven.)
Insert a small, flat blade screwdriver into
the guide hole and gently pull the cover
off.
Be careful to avoid breaking the glass or
chipping the paint.
Do not touch the bulb with bare fingers,
Use a clean cloth or paper towel to handle
the bulb. (Unlike the photo.)
Pull the bulb out of its socket. When
replacing it, be careful to avoid bending the
leads.
To replace the socket, you will need to
remove the side of the oven.
OVEN SENSOR
Remove the two screws securing the sensor
bracket to the back of the oven.
Pull the sensor forward into the oven
cavity. Be careful to avoid damaging the
wires on the edges when you pull them
through the hole.

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REPLACING OTHER ELECTRICAL COMPONENTS
WARNING! Electric shock hazard. The oven must be disconnected from the power
supply when making repairs and adjustments.
WARNING! Cut hazard. Many of the panels and sheet metal parts of the oven have
exceptionally sharp edges. Handle them with extreme caution. We
recommend wearing assembly gloves or some other type of safety hand
protection.
WARNING! Weight hazard. The double oven weighs over 250 pounds. Use care when
lifting the oven. Do not allow it to fall from its cabinetry. We recommend
using at least two people to lift the oven. A special dolly is available to
assist with removal and replacement of the oven.
In the following sections, it is necessary to remove the oven from its cabinetry.
Depending upon the components being serviced, various levels of disassembly will be
required. Use care, and be very careful of sharp edges.
To service the controls, remove the oven
far enough to remove the control covers.
Be careful the oven does not fall from its
cabinetry, as it weighs over 250 pounds.
It might be best to remove the oven
completely and set it on the floor.
Remove the 13 screws that secure the
three sections of the top cover.
The vent motor, the thermal limiter for the
cooling fan, and the door switch (top oven)
can be serviced here.