LG LMX21981 Series Training Manual

LG TRAINING MANUAL

LG TRAINING MANUAL

Four Door Refrigerator LMX21981**

Fall 2008

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 :

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

e b Co n t a C t s :

W

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

LMX21981xx REFRIGERATOR

LMX21981xx (REFRIGERATOR)

Leveling 7
Flooring 8
Handle Removal 8
Door Removal (Right and Left Doors) 9
Water Tube Connection 11
Water Line Installation Kit 12
Operation (Control Panel and Display) 14
Adjusting the Temperatures and Displays 16
Operating the Dispenser 17
Dispensing Crushed or Cubed Ice 17
Dispensing Water 17
Dispenser Light 17
Setting the Dispenser Lock 18
Setting the Door Alarm 18
Resetting the Filter Indicator 19
Activating ICE+PLUS 19
Diagnostic Failure Detection 19
Replacing the Water Filter 20
Disassembly 21
Removing and Replacing Refrigerator Doors 21
Icemaker Door 23
Remove and Replace the Pullout Freezer Door 23
Reinstall the Pullout Freezer Door 25
Dispenser Assembly 27
Display 29
Refrigerator LED 30
Door Switches (Refrigerator and Freezer) 30
Icemaker 31
Icemaking Mode 31
Harvest (Ejection) Mode 31
Fill / Park Mode 31
Icemaker Indicator Lights 080806 V. 0.99 31
Icemaker Cycle 32
Test Mode 32
Diagnostic Chart 33

Contents 1
Safety Notices and Warnings 3
Specifications 4
Parts Identification 5
Installation 6
Weight Hazard 7

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Icemaker (continued)
Error Codes 33
Main Control Board Conductor Reference (Photo) 34
Power From Board To Icemaker 35
Icemaker Removal 35
Icemaker Service Bulletin 37
Pilot Valve Assembly 40
Ice and Water Valves 41
Fan and Motor Disassembly 42
News Flash 42
Freezer Fan 42
Ice Room Fan 43
Condenser Fan 43
Evaporator and Ice Room Fan Access 43
Freezer Section Mullion 45
LED Lamps (Refrigerator) 45
Refrigerator Module Connector 46
How It Works 46
Refrigerator LED Module 48
Defrost Control Assembly 50
Thermistor Tips 51
Thermistors (Sensors) 52
Room Thermistor 52
Temperature Compensation 52
Multi-Duct 53
Stepper Motor 54
Compressor PTC (Positive Temperature Coefficient) 54
Compressor OLP (Overload Protector) 55
Replacing the OLP 56
Circuit Diagram (Block) 57
Test Mode 58
Error Codes 59
Error Code Er rt 60
PCB Function 61
Power Circuit 61
Load Fan and Door Open Detection Circuit 62
Open Door Detection Circuit Check 63
Refrigeration Compartment Stepping Motor Damper Circuit 64
LED in Refrigerator / Freezer (Optional) 64
Main PWB (Layout) 65
Dispenser Drive PWB Assembly 66
Exploded Views 67
Temperature Resistance Chart 73

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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.

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SPECIFICATIONS

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PARTS IDENTIFICATION

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INSTALLATION

WEIGHT HAZARD!

The refrigerator weighs as much as 325 pounds (148 kg). We recommend a minimum of
two people for moving and servicing this refrigerator.

LEVELING

Be sure the floor is level and strong enough to support the refrigerator. Unstable
installation or unleveled flooring may cause vibration, noise, and poor door operation. Be
sure to level the refrigerator at installation using the height adjusting screws (leveling
legs.)

If the base grille (kick plate) is installed,
remove it by removing the two screws that
hold it on.

When the refrigerator is in place, adjust the
leveling legs by turning them
counterclockwise to raise or clockwise to
lower the refrigerator.

Use an 11/32” (8 mm) wrench to turn the
hex ends of the leveling bolts or stick a flat
screwdriver in the slots to turn them. If you
have a helper to push against the top of
the refrigerator and take the weight off the
leveling legs, you can turn them by hand.
Be sure to lower them enough to contact
the floor and support some of the weight
of the refrigerator. It will keep it from
moving when you pull the doors open and
from tipping forward when the freezer
drawer is pulled out.

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Replace the base grille.

LMX21981xx REFRIGERATOR

FLOORING

The refrigerator must be installed on a solidly constructed floor to minimize noise and
vibration. The refrigerator must be level. If necessary, adjust the leveling legs under the
front of the refrigerator to compensate for variations in the flooring. This is easier if the
refrigerator is tipped slightly backward to take the weight off the legs. Turn them
clockwise to raise the refrigerator or counterclockwise to lower it.

Never install the refrigerator on a platform or a weakly supported structure.

When moving the refrigerator for cleaning or service, be sure to protect the floor. Pull
the refrigerator straight out. Do not walk or wiggle it; floor damage or side panel damage
may occur.

HANDLE REMOVAL

It may be necessary to remove the handles
to get the refrigerator through a door.

Loosen the set screws with a 3/32”
(2.5 mm) Allen wrench.

Remove the handle.
If the mounting bolts require removal or
adjustment, use a ¼” Allen wrench.

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Use extreme caution when removing the
handles to avoid scratching the doors.
When you remove or replace a handle,
push (or pull) firmly but do not damage the
handle or the door by using excessive
force.

Replace the handles by placing the handles
on the mounting bolts and tightening the
set screws.

LMX21981xx REFRIGERATOR

DOOR REMOVAL

Disconnect the electrical supply and shut off the water to the refrigerator before
installing or servicing.

Do not put your hands, feet, fingers, or metal (conductive) items into the air vents, the
base grille (kick plate), or bottom of the refrigerator. You could be injured or shocked.

If the entrance door is too small to accommodate the refrigerator, you can remove the
doors and pull the refrigerator into the room sideways.

RIGHT REFRIGERATOR DOOR

Open the door to 90°.
Remove the top hinge cover (1) screw.

Lift the cover (2).

Disconnect the wire (3) harness.

Rotate the hinge lever (4) clockwise and
remove it.

Lift the top hinge (5) clear of the hinge
lever latch (6).

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LMX21981xx REFRIGERATOR

LEFT REFRIGERATOR DOOR

Disconnect the hose at the top right
corner (facing the back) by removing the
release clip and pressing the release ring.
The tube will be pulled out with the door
when it is removed.

Open the door to 90°.

The door must be opened to 90° to be
removed or reattached.
Remove the screw (1) securing the top
hinge cover.

Use a flat screwdriver to pry off (2) the
hinge cover. (Hooks not shown.)

Remove the cover and pull the water tube
(3) through.

Disconnect all the wiring (4) harnesses.

Remove the ground (5) screws.

Turn the hinge lever (6) counter-clockwise
and remove it.

Lift the top hinge (7) free of the latch
lever (8).

Be careful the door does not fall forward.
With the door open to 90°, lift it off the
middle hinge pin.

CAUTION!

When lifting the hinge free of the latch, be careful the door does not fall forward. After
removing the door, lay it on a blanket or other padded protective surface, with the inside
facing up.

Replacement of either door is the reverse of the way it was removed.

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WATER TUBE CONNECTION

The water tube connections must be properly assembled to avoid leaking.

Insert the tube into the connector until
only one of the printed lines is visible.
Pull on the tube slightly to ensure proper
insertion and retention. Insert the retainer
clip under the release ring.

If you can see both rings, the tube is not
inserted properly. The tube end must be
cut squarely.

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WATER LINE CONNECTION

Read ALL the directions thoroughly before you begin. Be certain you understand all the
requirements for installing and connecting a water connection for this refrigerator.

WARNING! Connect the water supply tube from the refrigerator to a potable water
supply only.

The water pressure requirement for this refrigerator is 43 ~ 121 psi (3 ~ 8.5 kgf/cm2).
If the existing pressure is insufficient, the customer can purchase a separate pressure
pump to provide normal ice making and water dispensing operation.

• The total length of the water supply line should not be greater than 26 feet

(8 meters).

• Use copper tubing or a braided, reinforced nylon supply line.

• Install the water line in an area where the temperature will not drop below

freezing.

• It may take up to 24 hours for the icemaker to begin producing ice.

The icemaker water valve includes a flow washer that is used as a water pressure
regulator.

TOOLS REQUIRED

Standard screwdriver ¼” nut driver

7

/

” open-end wrench ½” open end wrench

16

¼” drill bit drill (electric drills must be grounded)

WATER LINE INSTALLATION KIT

Some dealers sell an installation kit that includes all the parts necessary to connect the
refrigerator to a water line. Often, these kits include a piercing saddle-type valve that
allows connection to the water line without the need for plumbing skills. LG does not
recommend the use of this type valve because it often fails to provide sufficient water

flow for the icemaker and dispenser to function properly.

continued on next page

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Various connector types are available.
These illustrations show a saddle valve with
the water line connected using a
compression fitting at each end.

The additional coil of tubing (approx­imately 7 feet or 2.1 m) is to allow pulling
the refrigerator out for servicing or
cleaning.

We recommend the use of a pre-assembled
braided plastic or nylon line with threaded
couplings on both ends to prevent leakage
and pop offs.

CONNECTING THE WATER LINE

We recommend using a flare nut wrench to connect the water line fittings. After the valve
has been installed on the water line, it must be flushed before connecting it to the
refrigerator Remove the plastic cap from the water valve on the back of the refrigerator.
Attach the water supply line to the valve. Open the valve and flush out the supply line
before attaching it to the refrigerator. Attach the supply line to the water valve on the
back of the refrigerator. Tighten all connections. Turn on the water and check for leaks.
Press the water dispenser button and bleed all the air through the system. When water
begins coming out, run another quart to be sure all the air is out of the line. Turn the
icemaker on and cycle it manually until water fills the tray to ensure all the air is out of
the line.

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OPERATION

1. LED DISPLAY
The LED display shows the temperature
settings, dispenser options, water filter,
door alarm, and locking status messages.

2. ICE TYPE BUTTON
The ICE TYPE button is used to select
Cubed Ice or Crushed Ice.

3. FREEZER BUTTON
Press the FREEZER button to adjust the
temperature in the freezer compartment.
NOTE: When pressed simultaneously with
the REFRIGERATOR button for more than
five seconds, the temperature display will
change from Fahrenheit to Celsius or vice
versa.

4. REFRIGERATOR BUTTON
Press the REFRIGERATOR button to adjust
the temperature in the refrigerator
compartment.
NOTE: When pressed simultaneously with
the FREEZER button for more than five
seconds, the temperature display will
change from Fahrenheit to Celsius or vice
versa.

5. ICE PLUS BUTTON
Press this button to turn on the ICE PLUS.
feature, which increases ice making
capabilities up to about 20 percent.

6. LIGHT/FILTER BUTTON
The LIGHT/FILTER button controls the
lamp in the dispenser. The LIGHT/FILTER
button resets the water filter replacement
indicator when the water filter has been
replaced.

7. ALARM/LOCK BUTTON
Press this button to control the door-open
alarm. Press this button to lock or unlock
all the other function buttons on the
control panel, including operation of the
dispenser.

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THE LED DISPLAY

The LED display shows the temperature
settings, dispenser options, water filter,
door alarm, and locking status messages.

1. DISPENSER SELECTION INDICATOR
Shows that Cubed ice or Crushed Ice
selection will be dispensed when the push
switch is pressed.

2. FREEZER TEMPERATURE
Indicates the set temperature of the
freezer compartment in degrees Celsius or
Fahrenheit.

3. REFRIGERATOR TEMPERATURE
Indicates the set temperature of the
refrigerator compartment in degrees
Celsius or Fahrenheit.

4. ICE PLUS
When the ICE PLUS button is pressed,
the display will indicate the selected
function has been activated.

5. DISPENSER LIGHT INDICATOR
When the LIGHT button is pressed,
the display will indicate the selected
function. When the dispenser light is on,
this indicator will appear on the display
panel.

6. DOOR ALARM INDICATOR
This indicator shows that the door-open
warning alarm is activated.

7. WATER FILTER STATUS
This indicator shows the current status for
the water filter. See Resetting the Filter
Indicator.

8. LOCK STATUS
This indicator shows the current status for
the control panel functions is set to LOCK.

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ADJUSTING THE TEMPERATURE AND DISPLAYS

Adjust Freezer Temperature

To adjust the temperature in the freezer
compartment, press the FREEZER button
to cycle through the range of available
settings.

Adjust Refrigerator Temperature

To adjust the temperature in the
refrigerator compartment, press the
REFRIGERATOR button to cycle through
the range of available settings.

NOTE: The actual inner temperature varies depending on the food status, since the
indicated temperature setting is the target temperature and not the actual temperature
within the refrigerator. Initially set the REFRIGERATOR CONTROL at 37 degrees F and
the FREEZER CONTROL at 0 degrees F. Leave them at these setting for 24 hours (one
day) to stabilize. Then adjust the compartment temperature as illustrated above.

To change the temperature display from
Fahrenheit to Celsius or vice versa,
simultaneously press and hold the
FREEZER and REFRIGERATOR buttons for
more than 5 seconds.

Display Power-Saving Mode
This function places the display into the
Power-Saving Mode.

Simultaneously press the FREEZER and ICE
PLUS buttons and hold them for 5 seconds
until a tone sounds. All LED lights will turn
on and then off. When the Power-Saving
Mode is activated, the display will remain
off until the next time the door is opened.
The display will also turn on when any
button is pressed, and it will remain on for
20 seconds after the last door opening or
button selection.
To deactivate the Power-Saving Mode,
press the FREEZER and ICE PLUS buttons
simultaneously and hold them for 5
seconds until the tone sounds.

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OPERATING THE DISPENSER

DISPENSING CRUSHER OR CUBED ICE

Press the ICE TYPE button to illuminate
the Crushed Ice icon. Press the push ice
switch with a glass or other container and
crushed ice will be dispensed.

Press the ICE TYPE button to illuminate
the Cubed Ice icon. Press the push switch
with a glass or other container and cubed
ice will be dispensed.

NOTE: Hold the glass or other container in place for a couple of seconds after
dispensing ice or water to catch the last few cubes or drops. The dispenser is designed to
not operate while either refrigerator door is open.

DISPENSING WATER

Press the push water switch or active water
button with a glass or other container and
chilled water will be dispensed. When the
water switch or active water switch is
pressed, the light will be illuminated.

NOTE: When operating the WATER
button; it does not work when you press
both ends and not the center. It works only
when you press the center of the button.

DISPENSER LIGHT

Press the LIGHT/FILTER button to turn the
dispenser light on and off.

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CAUTION

When filling the container with a small
opening, use it near the opening of the
water or ice dispenser as close as
possible.

SETTING THE DISPENSER LOCK

SETTING THE DOOR ALARM

Press and hold the ALARM/LOCK
button for three seconds to lock the
dispenser and all of the other control panel
functions. Press and hold again for three
seconds to unlock.

The ALARM/LOCK button also controls
the door alarm that sounds three times in
30-second intervals when a compartment
door is left open for more than 60
seconds. The alarm stops sounding when
the door is closed.

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RESETTING THE FILTER INDICATOR

Press and hold the LIGHT/FILTER button
for more than 3 seconds to reset the filter
indicator after the water filter has been
replaced.

NOTE: Replace the filter when the water
filter indicator light reaches 0 or whenever
the water or ice cube taste deteriorate
noticeably.

To purchase replacement water filter cartridges, visit your local appliance dealer or parts
distributor. You can also call 1-877-714-7486.

The replacement water filter cartridge’s part number is 5231JA2006A.

ACTIVATING ICE PLUS

Press the ICE+PLUS button once to
activate the ICE+PLUS function.
The ICE+PLUS icon on the display panel
will illuminate when activated.
The ICE+PLUS function runs the freezer
compartment at the coldest setting for a
24-hour period to increase icemaking by
up to about 20%, and then turns off
automatically.

NOTE:
Press the button again to cancel the
ICE+PLUS function.

DIAGNOSTIC FAILURE DETECTION

The diagnostic function automatically detects problems with your refrigerator, and a
diagnostic code will appear in the display.

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REPLACING THE WATER FILTER

Replace the filter when the water filter indicator decrements to 0 or the water dispenser
or icemaker noticeably decrease production.

Rotate the knob of the old cartridge
counterclockwise. When the cartridge is
released, you will feel it click out of place.

NOTE: Replacing the filter causes a small
amount of water (around 1 oz. or 25 cc)
to drain. Place a cup under the filter hole
to contain it.

Remove the old cartridge. Take the new
cartridge out of its packaging, and remove
the protective cover from the o-rings. Hold
the cartridge handle in its vertical position,
and firmly push the new filter cartridge into
place until it stops.

Use the handle to twist the cartridge
clockwise about one turn, until the handle
is in a horizontal position. You will feel the
filter click into place.

NOTE: If the filter will not turn from side to
side, it isn’t fully inserted.

After replacing the filter, dispense for 2
minutes from the water dispenser to purge
the water system. Check the filter for leaks.

When the water filter indicator displays the message 0 Filter Month, Hold 3 Seconds,
reset the water filter status display and indicator light by pressing and holding the
LIGHT/FILTER button for more than 3 seconds.

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DISASSEMBLY

REMOVING AND REPLACING REFRIGERATOR DOORS

CAUTION: Before you begin, unplug the refrigerator. Remove food and bins from doors.

Left Door – FIGURE 2 (Next Page)

1. Disconnect water supply tube by pushing back on the disconnect ring (4).
See FIGURE 1, next page.

2. Open the left door. Loosen the top hinge cover screw (1). Use a flat tip
screwdriver to pry back the hooks on the front underside of cover (3).
Lift up the cover.

3. Disconnect the door switch wire harness (2). Remove the cover.

4. Pull out the tube.

5. Disconnect the three wire harnesses (5). Remove the grounding screw (6).

6. Rotate hinge lever (7) counterclockwise and remove. Lift the top hinge (8) free of
the hinge lever latch (9).

CAUTION: When lifting the hinge free of the latch, be careful that the door does not
fall forward.

7. Place the door, inside facing up, onto a non-scratching surface.

Right Door – FIGURE 3 (Next Page)

1. Open the door. Loosen the top hinge cover screw (1). Lift up the cover (3).

2. Disconnect the door switch wire harness (2). Remove the cover.

3. Disconnect the wire harness (5).

4. Rotate the hinge lever (6) clockwise and remove. Lift the top hinge (7) free of the
hinge lever latch (8).

CAUTION: When lifting the hinge free of the latch, be careful that the door does not
fall forward.

5. Lift door the up from middle hinge pin (9) and remove the door.

6. Place the door, inside facing up, onto a non-scratching surface.

See drawings, next page.

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