LG LFX31925 Series User manual

CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODEL : LFX31925**
COLOR : STAINLESS(ST)
SMOOTH BLACK(SB)
SUPER WHITE(SW)
REFRIGERATOR
SERVICE MANUAL

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CONTENTS
SAFETY PRECAUTIONS ....................................................................................................................................................... 2
1. SPECIFICATIONS ............................................................................................................................................................. 3
2. PARTS IDENTIFICATION ................................................................................................................................................. 4
3. DISASSEMBLY ................................................................................................................................................................ 5-
REMOVING AND REPLACING REFRIGERATOR DOORS .......................................................................... 5
DOOR .............................................................................................................................................................. 6
DOOR ALIGNMENT ....................................................................................................................................... 7
FAN AND FAN MOTOR................................................................................................................................... 7
DEFROST CONTROL ASSEMBLY ................................................................................................................ 7
REFRIGERATOR LIGHT (TOP) .................................................................................................................. 8-9
MULTI DUCT .................................................................................................................................................. 9
DISPENSER ................................................................................................................................................. 10
DISPLAY PCB .............................................................................................................................................. 10
ICE BUTTON ASSEMBLY ............................................................................................................................ 10
WATER BUTTON ASSMEBLY ..................................................................................................................... 10
ICE CORNER DOOR REPLACEMENT ........................................................................................................ 10
ICEMAKER REPLACEMENT ....................................................................................................................... 11
SUB PCB FOR WORKING DISPENSER ..................................................................................................... 11
CAP DUCT MOTOR REPLACEMENT ......................................................................................................... 12
HOW TO REMOVE A ICE BIN ..................................................................................................................... 13
HOW TO INSERT A ICE BIN ........................................................................................................................ 13
HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER ......................................................... 14-15
WATER VALVE DISASSEMBLY METHOD .................................................................................................................... 16
FAN AND FAN MOTOR DISASSEMBLY METHOD......................................................................................................... 16
PULL OUT DRAWER ...................................................................................................................................................... 17
CAUTION : SEALED SYSTEM REPAIR ......................................................................................................................... 18
4. ADJUSTMENT ................................................................................................................................................................ 19
COMPRESSOR ................................................................................................................................................................ 19
5. CIRCUIT DIAGRAM ........................................................................................................................................................ 20
6. TROUBLESHOOTING .................................................................................................................................................... 21
7. PCB PICTURE ........................................................................................................................................................... 22-23
8. Troubleshooting With Error Display ....................................................................................................................... 24-35
9. Troubleshooting Without Error Display ................................................................................................................. 36-44
10. Reference .................................................................................................................................................................. 35-50
11. COMPONENT TESTING INFORMATION ................................................................................................................. 51-59
12. TROUBLESHOOTING .............................................................................................................................................. 60-72
13. ICEMAKER OPEARTING AND TROUBLE SHOOTING METHOD ......................................................................... 73-76
14. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM ........................................................................................... 77-80
SAFETY PRECAUTIONS
Please read the following instructions before servicing your refrigerator.
1. Unplug the power before handling any elctrical componets.
2. Check the rated current, voltage, and capacity.
3. Take caution not to get water near any electrical components.
4. Use exact replacement parts.
5. Remove any objects from the top prior to tilting the product.

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1. SPECIFICATIONS
1-1 LFX31925**
DOOR DESIGN
DIMENSIONS (inches)
NET WEIGHT (pounds)
COOLING SYSTEM
TEMPERATURE CONTROL
DEFROSTING SYSTEM
DOOR FINISH
HANDLE TYPE
INNER CASE
INSULATION
ITEMS
Side Rounded
35 3/4 X 36 1/4 X 70 1/4 (WXDXH) 31cu.ft.
158kg (348lb)
Fan Cooling
Micom Control
Full Automatic
Heater Defrost
PCM, VCM, Stainless
Bar
ABS Resin
Polyurethane Foam
SPECIFICATIONS
●31 cu.ft.
VEGETABLE TRAY
COMPRESSOR
EVAPORATOR
CONDENSER
REFRIGERANT
LUBRICATING OIL
DEFROSTING DEVICE
ITEMS
Clear Drawer Type
Linear
Fin Tube Type
Spiral Condenser
R-134a (135 g)
ISO10 (280 ml)
SHEATH HEATER
LED Module
LED Module
SPECIFICATIONS
LAMP REFRIGERATOR
FREEZER
●DIMENSIONS
Depth w/ Handles
Depth w/o Handles
Depth w/o Door
Depth (Total with Door Open)
Height to Top of Case
Height to Top of Door Hinge
Width
Width (door open 90 deg. w/o handle)
Width (door open 90 deg. w/ handle)
A
B
C
D
E
F
G
H
I
36 1/4 in
33 3/4 in
29 1/2 in
48 1/8 in
68 3/4 in
70 1/4 in
35 3/4 in
40 in
45 in
Description LFX31925**

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2. PARTS IDENTIFICATION
Water filter
The water filter purifies
water.
LED interior lamps
The interior lamps light up the
inside of the refrigerator.
Dairy product bin
The dairy product bin is
used to preserve dairy
products.
Adjustable refrigerator
shelf
The refrigerator
compartment shelves
are adjustable to allow
flexibility for storage
needs. Preserve large
size food or containers.
Modular door bin
Interchangeable bins can
be arranged to suit your
storage needs.
Auto closing hinge
The refrigerator doors
and freezer drawers
close automatically when
you push them slightly.
(The door only closes
automatically when it is
open at an angle of less
than 30°C.)
Glide'N'Serve
When you want to store
food items at a much
lower temperature, you
can use the temperature
controller to maintain the
lowest possible chilling
temperature (without
freezing).
F-Basket
This is a convenient
feature that allows you
to fill small frozen food,
beverage to needed
quick cooling.
The filter should be replaced
every 6 months. Please refer
to°Replacing the filter°
in this manual for details.
* This function may not be
available, depending on
the model.
Indoor ice bin
100 ice cubes are
automatically produced over
per 24-hour period.
Crisper
The crisper controls humidity
and helps vegetables and
fruit to stay crisp.
Fixed door bin
The fixed door bin is used
to preserve chilled food or
drinks that are of a suitable
size for storing in this bin.
Pull out Drawer
It is a convenient feature
that allows you to fill large
containers such as the extra
bin and It is useful to store.
Dura Base® Divider
This is a convenient feature that
allows you to fill large containers,
such as an ice chest, cooler or
pitcher, with ice.
NOTE

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3. DISASSEMBLY
3-1 REMOVING AND REPLACING REFRIGERATOR DOORS
●Removing Refrigerator Door
CAUTION: Before you begin, unplug the refrigerator. Remove food and bins from doors.
▶Left Door -FIG. 2
1. Disconnect water supply tube by pushing back on the disconnect ring (3).-FIG. 1
2. Open door. Loosen top hinge cover screw (1).
Use flat tip screwdriver to pry back hooks on front underside of cover (2). Lift up cover.
3. Disconnect door switch wire harness and remove the cover.
4. Pull out the tube.
5. Disconnect all 3 wiring harnesses (4). Remove the grounding screw (5).
6. Rotate hinge lever (6) counterclockwise. Lift top hinge (7) free of hinge lever latch (8).
7. Lift door from middle hinge pin and remove door.
8. Place the door with the insides facing up, on a not scratch surface.
CAUTION: When lifting hinge free from the latch, be careful that door does not fall forward.
▶Right Door -FIG. 3
1. Open the door, remove 1 screw on the top of the hinge cover. Loosen top hinge cover screw (1). Lift up cover (2).
2. Disconnect door switch wire harness and remove the cover.
3. Rotate hinge lever (3) clockwise. Lift top hinge (4) free of hinge lever latch (5).
4. Lift door from middle hinge pin and remove door.
5. Place the door with the insides facing up, on a not scratch surface.
CAUTION: When lifting hinge free from the latch, be careful that the door does not fall forward.
Correct Incorrect
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Figure 2 Figure 3
Figure 1
1) Insert the tube until you can see only one of
the lines printed on the tube.
2) After inserting, pull the tube to ascertain that
it is secure.
3) Assemble clip.

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1. Remove gasket
Remove the gasket from gasket channel at doorliner as
shown in the illustration below.
3-2 DOOR
●Mullion Removal
1. Remove 2 screws.
●Door Gasket Removal
2. Lift mullion up carefully.
3. Disconnect wire harness.
●Door Gasket Replacement
1. Insert gasket into channel
Insert and press gasket into channels at doorliner.
2. Insert mullion into channel.
Insert the mullion into channel at door as shown below.
●Mullion Replacement
1. Connect wire harness.
3. Assemble 2 screws.
Gasket
Gasket
Channel

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* Ice Fan Assembly Replacement
1) Remove the plastic guide for slides on left side by
unscrewing phillips head screws.
2) Pull out the cover sensor to disassemble by using tools
shown in the figure.
3) Pull out the cover grille to disassemble by using tools
shown in the figure.
4) Put your hand into the inside of grille to disassemble
shown in the figure.
5) Disconnect wire harness of the grille assembly.
6) Remove the Ice fan assembly by loosening all screws.
(1) (2)
(3) (4)
(5) (6)
3-5 DEFROST CONTROL ASSEMBLY
Defrost Control assembly consists of Defrost Sensor and
FUSE-M.
The Defrost Sensor works to defrost automatically. It is
attached to the metal side of the Evaporator and senses its
temperature. At 46F(8°C), it turns the Defrost Heater off.
Fuse-M is a safety device for preventing over-heating of
the Heater when defrosting.
1. Pull out the grille assembly. (Figure 1)
2. Separate the connector with the Defrost Control
assembly and replace the Defrost Control assembly after
cutting the Tie Wrap. (Figure 2)
GRILLE ASSEMBLY DEFROST-CONTROL
ASSEMBLY
3-3 Door Alignment
If the level of refrigerator doors is uneven, follow the
instructions below to align the doors:
Turn the leveling legs (CCW) to raise or (CW) to lower the
height of the front of the refrigerator by using flat blade
screw driver or 11/32" wrench. Use the wrench (Included
with the User Manual) to adjust the bolt in the door hinge to
adjust the height. (CW to raise or CCW to lower the height.)
3-4 FAN AND FAN MOTOR
1. Remove the freezer drawer.
2. Remove the plastic guide for slides on left side by
unscrewing phillips head screws.
3. Remove the grille assembly by removing four screws
and pulling the grille assembly forward.
4. Remove the Fan Motor assembly by loosening 3 screws
and disassembling the shroud.
5. Pull out the fan and separate the Fan Motor and Bracket
Motor.
FAN MOTOR
BRACKET
MOTOR
Shroud
Up
Down
Ice Fan Assembly

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3-6 Refrigerator Light (Top)
Unplug Refrigerator, or disconnect power at the circuit
breaker.
If necessary, remove top shelf or shelves.
1) Release 2 screws.
2) Hold both ends with your both hands and pull it
downward to remove it.
3-6-1 Refrigerator Compartment Lamp
4) Use a flat blade screwdriver as shown below to remove
the cover lamp.
5) To remove the LED Assembly, open the Hook part to pull
it out as shown in the following picture.
Cover, lamp
Case, lamp
LED, Assembly
3) To remove the case lamp and cover lamp, release
another 2 screws as following picture.
3-6-2 Refrigerator Light (Side)
1. Unplug refrigerator power cord from electric outlet.
2. Put flat screwdriver into sevice hole and remove cover of
refrigerator light.
3. Remove the LED assembly from connector.
4. Replace LED assembly.
5. Assemble the cover in reverse order.

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3-7 MULTI DUCT
3-6-3 Cap Duct LED LAMP(Bottom)
1. Unplug refrigerator power cord from electric outlet.
2. Open the refrigerator door to need diassembly.
3. Put flat screwdriver into service hole, remove the cover
of cap duct LED LAMP.
5. Replace LED assembly.
6. Assembly the cover in reverse order.
4. Remove the LED assembly from connector.
1. Remove 2 screws and guide rail.
2. Remove the upper and lower Caps by using a flat
screwdriver and remove 2 screws as shown figure.
3. Disconnect the lead wire on the bottom position
4. Grip both side of multi duct, pull it out.

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3-12 ICE CORNER DOOR REPLACEMENT
1) Loosen the front screw as shown in the picture.
2) Lift up the hinge with one hand.
3) Pull out the Ice Corner Door with the other hand.
3-11 WATER BUTTON ASSMEBLY
1) Remove screws.
2) Grasp the Button assembly and lift.
Button Lever
hinge
3-8 DISPENSER
1) Pull out the drain 2) Holding the inner side of
the dispenser pull
forward to remove.
3-9 DISPLAY PCB
As shown below, remove 1 screw on the PCB fixing screw.
Remove the display PCB fixing screw.
3-10 ICE BUTTON ASSEMBLY
1) Remove the 1 screw holding the lever.
2) Remove the spring from the hook.
3) Push and pull on the tab to remove.
CAUTION: When replacing the dispenser cover make
sure the lead wire does NOT come off and the water line
is not pinched by the dispenser.
Button Lever
Case, PCB Display PCB
3) If nozzle is interfered with button,
push and pull out the bottom of
button.
4) Remove the
lead wire.

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3-13 ICEMAKER REPLACEMENT
1) Remove 4 screws as shown.
2) Grasp the bottom of motor cover assembly and pull
slowly.
3) Disconnect wire harness from wall of compartment.
In-door
motor
3-14 SUB PCB FOR WORKING DISPENSER
1) Disconnect the wire harness.
2) Remove 1 screw from PCB and replace with new PCB.
CAUTION: Make sure that the motor housing is taped to
the mold, if not positioned correctly the cover will not fit
properly.

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3-15 CAP DUCT MOTOR REPLACEMENT
1) Separate the Housing of the Cap Duct Motor.
3) When replacing the motor, check the position of the door
duct and the link for proper fit.
Link
Duct Door
Cap Duct Motor
NG Position
2) Unscrew 3 screws to disassemble the motor.
4) Insert 2 screws.
5) Push housing aside.

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3-16 HOW TO REMOVE A ICE BIN
1) Grip the handles, as shown.
2) Tilt and lift slightly as shown.
3-17 HOW TO INSERT A ICE BIN
1) Insert the Ice Bin, slightly tilting to avoid touching the
Icemaker. (Especially, Ice-Detecting Sensor)

3) Remove ice bin slowly.

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3-18 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER
3-18-1 Follow Steps to Remove
Step 1) Open the freezer door.
Step 3) Remove the two screws from the guide rails (one
from each side).
Step 2) Remove the lower basket.
Step 4) Removal of the freezer door is done by l ifting clear
of the rail support.
Fully extend both rails.
Step 5) Remove only 1 screw of gearice, and disassemble
the bar and gearice
Step 6) Remove 2 screws of both side of supporter covers
tv and disassemble the supporter cover tv.

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3-18-2 Follow Steps to Reinstall
Step 6) Reinstall the freezer door by inserting the rail tabs
into the guide rail.
* Assemble them like as pictures
Step 8) Reinstall the lower basket, and close the freezer
door.
Step 5) The rail system will align itself by pushing the rails
all the way into the freezer section.
Pull the rails back out to full extension.
Step 7) Reinstall the two screws into the guide rails
(one from each side).
Step 1) Insert both side of supporter cover tv into
connector rails, and then screw them.
Step 2) ①Assemble a bar and gear ice with screw.
②Push the otherside of the gear to inside of the
bar.
Step 3) Put gear ice assembled with the bar by screw into
connector rail’s hole.
Step 4) Insert opposite gear ice into connector rail and
screw them

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3-19 WATER VALVE DISASSEMBLY METHOD
1) Turn off the water to unit. Remove the waterline from the
valve.
3-20 FAN AND FAN MOTOR DISASSEMBLY
METHOD
1) Remove screws for the Drain Pipe Assembly and the 1
connected to the Motor Cover.
2) Remove cover and 1 screw from the valve.
3) Separate the housing and remove the valve.
4) Remove the clip, and press the collet to separate the
tube from the connector. Note: there maybe some water
in the line.
Mechanical Cover
Housing
MOTOR COVER
2) Separate the Fan Assembly and Motor, turn counter
clockwise to remove from the motor shaft.
FAN ASSEMBLY MOTOR
Assemble in reverse order. Taking care to avoid.
1. Do not to bend the tube during assembly.
2. Press the Water Dispenser button letting water pour out,
this checks for any leaks in the tube connection, this may
vary depending on the water pressure
( about 2 minutes.).

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3-21 PULL OUT DRAWER
Top Drawer
1. Use a flat blade screwdriver to push the tab in on the left rail and push the tab on the right rail in with your finger.
Once the tabs have been pushed in, you can lift the tray up and out.
2. Pull both rails out to the full extension and insert the insert the back of the tray into both rails. Then set the front of the
tray into the rail and push it until you hear it click into place.
Middle Drawer
1. To remove the middle drawer.
Pull the drawer out to full extension. Lift the front of the drawer up, then pull it straight out.
2. To install, slightly tilt up the front and insert the drawer into the frame and push it back into push it back place.

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3-22. CAUTION : Sealed System Repair
Before making a sealed system repair : Start with the power cord unplugged from the outlet. Plug in the power cord and
between 6 and 12 seconds after it has been pugged in, unplug it from the power source. this will allow both sides of the 3
way valve to be opened to allow for proper evacuation.
3 Way Valve Service
■The 3 way valve has plastic parts inside, so always wrap it
with a wet cloth before servicing when using a torch.
1) Always replace the 3 way valve if there is a leak at any one
of the 3 tubes coming from it.
2) Service in replacement of valve (valve failure) Perform
service in the same method as above.

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4. ADJUSTMENT
4-2-3 Compressor protection logic
Since linear Comp conducts linear reciprocating motion,
we have protection logic for compressor, motor and PCB
as the below.
- Stroke Trip
During the operation, if stroke is above the target value,
decrease the target volt by 3V.
- Current Trip
Current trip is set in order to protect compressor
mechanical part and drive from the overcurrent that might
arise during the operation.
Check the current for every 416.7us and if the Trip
exceeds 1.86Arms more than three times at Comp ON,
forcibly stop and restart six minutes later.
- Lock Piston Trip
If stroke is under 5mm even if the current is more than
14Arms, Take it as ‘piston lock’ and restart after 2’30” of
Comp OFF. Check the current and stroke for every
416.7us and if the condition fits more than three times at
Comp ON, the Trip occurs.
- IPM fault Trip
It occurs if FO signal received from IPM is LOW. For
every 416.7us, check whether FO signal is LOW. The trip
occurs if it is found three times during the five
periods(83ms).
4-1-1 Role
4-1 COMPRESSOR
The compressor intakes low temperature and low pressure
gas from the evaporator of the refrigerator and compresses
this gas to high-temperature and high-pressure gas. It then
delivers the gas to the condenser.
4-1-2 Note for Usage
(1) Be careful not to allow over-voltage and over-current.
(2) Do not drop or handle carelessly.
(3) Keep away from any liquid.
If liquid such as oil or water enters the Cover PTC
Compressor may fail due to breakdown of their
insulating capabilities.
(4) Always use the Parts designed for the compressor and
make sure it is properly attached to the compressor.
Parts may appear physically identical but could have
different electrical ratings. Replace parts by part number
and model number. Use only approved substitute parts.
4-1-3 Remove the cover PTC
(1) Remove the Cover Back M/C
(2) Remove two screws on comp base
(3) Use a L-shaped flap tooll to pry off the cover
(4) Assembly in reverse order of disassembly

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5. CIRCUIT DIAGRAM