LG LFX28978 series, LFX25978 series Service Manual

REFRIGERATOR

SERVICE MANUAL

CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

MODEL : LFX28978**

LFX25978**

COLOR : STAINLESS(ST)

SMOOTH BLACK(SB) SUPER WHITE(SW)

CONTENTS

SAFETY PRECAUTIONS ....................................................................................................................................................... 2

1. SPECIFICATIONS .......................................................................................................................................................... 3-4

2. PARTS IDENTIFICATION ................................................................................................................................................. 5

3. DISASSEMBLY ............................................................................................................................................................ 6-17

REMOVING AND REPLACING REFRIGERATOR DOORS ............................................................................................. 6

DOOR ................................................................................................................................................................................ 7

DOOR ALIGNMENT .......................................................................................................................................................... 8

FAN AND FAN MOTOR(EVAPORATOR) ......................................................................................................................... 8

DEFROST CONTROL ASSEMBLY ................................................................................................................................... 8

LAMP ................................................................................................................................................................................. 9

MULTI DUCT ..................................................................................................................................................................... 9

MAIN PWB ....................................................................................................................................................................... 10

DISPENSER .................................................................................................................................................................... 10

DISPLAY PCB ................................................................................................................................................................. 10

ICE BUTTON ASSEMBLY ............................................................................................................................................... 10

WATER BUTTON ASSMEBLY ........................................................................................................................................ 11

ICE CORNER DOOR REPLACEMENT ........................................................................................................................... 11

ICEMAKER REPLACEMENT ..................................................................................................................................... 11-12

SUB PWB FOR WORKING DISPENSER ....................................................................................................................... 12

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

DRAWER REMOVAL ...................................................................................................................................................... 17

4. ADJUSTMENT ................................................................................................................................................................ 18

5. CIRCUIT DIAGRAM ................................................................................................................................................... 19-20

6. TROUBLESHOOTING .................................................................................................................................................... 21

7. PCB PICTURE ........................................................................................................................................................... 22-24

8. Troubleshooting With Error Display ....................................................................................................................... 25-33

9. Troubleshooting Without Error Display ................................................................................................................. 34-42

10. Reference .................................................................................................................................................................. 43-46

11. COMPONENT TESTING INFORMATION ................................................................................................................. 47-55

12. COMPRESSOR TROUBLESHOOTING ................................................................................................................... 56-68

13. ICEMAKER OPEARTING AND TROUBLE SHOOTING METHOD ......................................................................... 69-72

14. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM ........................................................................................... 73-76

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.

- 2 -

1. SPECIFICATIONS

1-1 LFX28978**

28 cu.ft.

ITEMS

DOOR DESIGN

DIMENSIONS (inches)

NET WEIGHT (pounds)

COOLING SYSTEM

TEMPERATURE CONTROL

DEFROSTING SYSTEM

DOOR FINISH

HANDLE TYPE

INNER CASE

INSULATION

DIMENSIONS

SPECIFICATIONS

Side Rounded

/4 X 35 3/8 X 69 3/4 (WXDXH) 28cu.ft.

155kg (342lb)

Fan Cooling

Micom Control

Full Automatic

Heater Defrost

PCM, VCM, Stainless

Bar

ABS Resin

Polyurethane Foam

ITEMS

VEGETABLE TRAY

COMPRESSOR

EVAPORATOR

CONDENSER

REFRIGERANT

LUBRICATING OIL

DEFROSTING DEVICE

LAMP

REFRIGERATOR

FREEZER

SPECIFICATIONS

Clear Drawer Type

Linear

Fin Tube Type

Spiral Condenser

R-134a (140 g)

ISO10 (280 ml)

SHEATH HEATER

LED Module(24)

Bulb Lamp

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)

Description LFX28978**

35 3/8 in

32 7/8 in

29 in

47 5/8 in

68 3/8 in

69 3/4 in

35 3/4 in

39 1/4 in

44 1/4 in

- 3 -

1-2 LFX25978**

25 cu.ft.

ITEMS

DOOR DESIGN

DIMENSIONS (inches)

NET WEIGHT (pounds)

COOLING SYSTEM

TEMPERATURE CONTROL

DEFROSTING SYSTEM

DOOR FINISH

HANDLE TYPE

INNER CASE

INSULATION

DIMENSIONS

SPECIFICATIONS

Side Rounded

/32 X 35 3/8 X 69 3/4 (WXDXH) 25cu.ft.

142kg (313lb)

Fan Cooling

Micom Control

Full Automatic

Heater Defrost

PCM, VCM, Stainless

Bar

ABS Resin

Polyurethane Foam

ITEMS

VEGETABLE TRAY

COMPRESSOR

EVAPORATOR

CONDENSER

REFRIGERANT

LUBRICATING OIL

DEFROSTING DEVICE

LAMP

REFRIGERATOR

FREEZER

SPECIFICATIONS

Clear Drawer Type

Linear

Fin Tube Type

Spiral Condenser

R-134a (125 g)

ISO10 (280 ml)

SHEATH HEATER

LED Module(24)

Bulb Lamp

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)

Description LFX25978**

35 3/8 in

32 7/8 in

29 in

46 3/64 in

68 3/8 in

69 3/4 in

32 23/32 in

36 7/32 in

41 7/32 in

- 4 -

2. PARTS IDENTIFICATION

ADJUSTABLE REFRIGERATOR SHELVING

The refrigerator compartment shelves are adjustable to allow flexibility for storage needs.

GALLON STORAGE BINS

Three interchangeable bins can be arranged to suit your storage needs.

REMOVABLE ICE STORAGE BIN

The ice storage bin can be removed to fill ice buckets, coolers, or pitchers.

LED INTERIOR LAMPS

Refrigerator interior is lit by the LED array.

CAN STORAGE BIN

FIXED DOOR BIN

- 5 -

3. DISASSEMBLY

Correct

Incorrect

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).

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

7. Lift door from middle hinge pin and remove door.

8. Place the door with the insides facing up, on a not scratch surface.

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.

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

5. Place the door with the insides facing up, on a not scratch surface.

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.

- 6 -

3-2 DOOR

Mullion Removal

1. Remove 2 screws.

Door Gasket Replacement

1. Insert gasket into channel

Press gasket into channels on the four remaining sides of door.

2. Lift Mullion up carefully.

3. Disconnect wire harness.

Figure 1

Figure 2

Figure 3

Figure 5

Mullion Replacement

1. Connect wire harness.

Figure 6

2. Insert mullion into the channel.

Insert the cover assembly into bracket, door.

Door Gasket Removal

1. Remove gasket

Pull gasket free from gasket channel on the four remaining sides of door.

Figure 4

Figure 7

3. Assemble 2 screws.

Figure 8

- 7 -

3-3 Door Alignment

If the space between the door are uneven, follow the instructions to align them. Remove the Base Grillie. Turn the leveling legs counter clock wise to raise or clock wise 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. (CCW to raise or CW to lower the height.)

Figure 9

* Ice Fan Scroll Assembly Replacement

1) Remove the plastic guide on the left side, using a phillips screwdriver to remove the screws.

2) Pull off the sensor cover.

3) Remove the grill cover.

4) Gently pull on the grill assembly to remove.

5) Disconnect the wiring harness.

6) Remove all screws on the scroll assembly.

(1) (2)

(3) (4)

3-4 FAN AND FAN MOTOR(EVAPORATOR)

1. Remove the freezer drawer. (If your refrigerator has an icemaker, remove the icemaker first)

2. Remove the plastic guide for slides on left side by unscrewing phillips head screws.

3. Remove the grille by removing 4 screws and pulling the grille 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.

FAN MOTOR

Shroud

(5) (6)

Figure 11

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 12)

2. Separate the connector with the Defrost Control assembly and replace the Defrost Control assembly after cutting the Tie Wrap. (Figure 13)

GRILLE ASSEMBLY

DEFROST-CONTROL ASSEMBLY

BRACKET

MOTOR

Figure 10

- 8 -

Figure 12

Figure 13

3-6 LAMP

Unplug, or disconnect power at the circuit breaker. If necessary, remove top shelf or shelves.

3-6-1 Refrigerator Compartment Lamp

1) Release 2 screws.

2) Hold both ends and pull down to remove.

Figure 14

3) To remove the lamp case and cover, release 2 screws as shown.

Figure 15

4) Use a flat tool as shown below to remove the lamp cover.

3-6-2 Freezer Compartment Lamp

1. Unplug refrigerator power cord form outlet.

2. Remove screw with driver.

3. Grasp the cover Lamp, pull the cover downward.

Figure 18

3-7 MULTI DUCT

1. Romove the upper and lower caps with a flat screwdriver and remove 2 screws. (Figure 19)

2. Disconnect the lead wire on the bottom position.

Figure 16

5) To remove the LED assembly, pull apart the cover.

Case, lamp

Cover, lamp

LED, Assembly

Figure 17

Figure 19

- 9 -

3-8 MAIN PWB

1) Loosen 3 screws on the PWB cover.

Figure 20

2) Remove the PWB cover

Figure 21

3) Disconnect wire harness and replace the main PWB in the reverse order of removal.

Figure 26 Figure 27

4) Holding the inner side of the dispenser pull forward 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.

5) Remove the lead wire.

Figure 28

3-10 DISPLAY PCB

As shown below, remove 1 screw on the PCB fixing screw. Remove the display PCB fixing screw.

Figure 22

3-9 DISPENSER

Figure 23 Figure 24

1) Pull out the drain

3) If nozzle is interfered with button, push and pull out the bottom of button and then pull out the right side.

2) Use these 2 holes to pull out the bottom

Figure 25

Case, PCB

Case, PCB Display PCB

3-11 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.

Button Lever

- 10 -

Display PCB

Figure 28

Figure 29

Figure 30

3-12 WATER BUTTON ASSMEBLY

1) Remove screws.

2) Grasp the Button assembly and lift.

Button Lever

Figure 31

3-13 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.

3-14 ICEMAKER REPLACEMENT

1) Remove 4 screws as shown.

Figure 33

2) Grasp the bottom of motor cover assembly and pull slowly.

hinge

Figure 34

3) Disconnect wire harness from wall of compartment.

Figure 32

In-door motor

Figure 35

- 11 -- 11 -

CAUTION: Make sure that the motor housing is taped to

the mold, if not positioned correctly the cover will not fit properly.

Figure 36

3-16 CAP DUCT MOTOR REPLACEMENT

1) Separate the Housing of the Cap Duct Motor.

Figure 39

2) Unscrew 3 screws to disassemble the motor.

Figure 40

3-15 SUB PWB FOR WORKING DISPENSER

1) Disconnect the wire harness.

Figure 37

2) Remove 1 screw from PWB and replace with new PWB.

Figure 38

3) When replacing the motor, check the position of the door duct and the link for proper fit.

Duct Door

Link

Cap Duct Motor

NG Position

Figure 41

4) Insert 2 screws.

Figure 42

5) Push housing aside.

Figure 43

- 12 -

3-17 HOW TO REMOVE A ICE BIN



1) Grip the handles, as shown.

Figure 44

2) Tilt and lift slightly as shown.

3-18 HOW TO INSERT A ICE BIN

1) Insert the Ice Bin, slightly tilting to avoid touching the Icemaker. (Especially, Ice-Detecting Sensor)

Figure 47

3) Remove ice bin slowly.

Figure 45

Figure 46

- 13 -

3-19 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER

3-19-1 Follow Steps to Remove

Step 1) Open the freezer door. Step 2) Remove the lower basket.

Figure 48 Figure 49

Step 3) Remove 2 screws one on each side of the guide

rails.

Step 5) First: Remove the gear from the left side first by releasing the tab behind the gear, place a screwdriver between the

gear and the tab and pull up on the gear.

Second: Remove the center rail.

Third: Remove the gear from the right side by following the same steps for the left side.

Step 4) Removal of the freezer door is done by lifting clear

of the rail support. Fully extend both rails.

Figure 51Figure 50

NOTE: THIS TAB MUST BE PUSHED IN TO RELEASE THE GEAR.

Figure 52

- 14 -

3-19-2 Follow Steps to Reinstall

Step 1) Reinstall the right side of the gear into the clip.

Figure 53

Step 2) Insert the rail into the right side of the gear. Gears

do not need to be perpendicular to each other.

Step 4) 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 3) Insert the rail into the left side of the gear, and

insert the gear into the clip.

Figure 55Figure 54

Step 5) Reinstall the freezer door by inserting the rail tabs

into the guide rail.

Step 6) Reinstall 2 screws into the guide rail one on each

side.

Figure 56 Figure 57

Step 7) Reinstall the lower basket, and close the freezer

door.

Figure 59Figure 58

- 15 -

3-20 WATER VALVE DISASSEMBLY METHOD

1) Turn off the water to unit. Remove the waterline from the valve.

3-21 FAN AND FAN MOTOR DISASSEMBLY

METHOD

1) Remove screws for the Drain Pipe Assembly and the 1 connected to the Motor Cover.

MOTOR COVER

Figure 60

2) Remove cover and 1 screw from the valve.

Mechanical Cover

Figure 61

3) Separate the housing and remove the valve.

Housing

Figure 62

4) Remove the clip, and press the collet to separate the tube from the connector. Note: there maybe some water in the line.

Figure 64

2) Separate the Fan Assembly and Motor, turn counter clockwise to remove from the motor shaft.

FAN ASSEMBLY MOTOR

Figure 65

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.).

Figure 63

- 16 -

3-22 Drawer Removal

Fully extend the drawer and lift from the front pulling straight out.

Figure 66

To install the drawer back into the frame, tilt the front sightly and pushingt back into place.

Figure 67

- 17 -

4. ADJUSTMENT

4-1 COMPRESSOR

4-1-1 Role

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

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).

(1) Remove the Cover Back M/C

(2) Loosen two screws on comp base

(3) Use a L-shaped flap tooll to pry off the cover (4) Assembly in reverse order of disassembly

- 18 -

5. CIRCUIT DIAGRAM

LFX28978**

- 19 -

LFX25978**

- 20 -

6. TROUBLESHOOTING

6-1 Error Code Summary

WARNING: When checking Resistance values, make sure to

turn off the power, and wait for the voltage to discharge.

NOTE) Within 3 hours after the error : Press the Ice Plus button and Freezer button simultaneously

3 hours after the error : All errors, except for "Er rt", "Er SS", "Er IS(except for Icing sensor)", "Er gF", "Er It" error, are displayed. "Er IS" which is displayed without input of user is the error of Icing Sensor.

Error Display

Error Detection

LG LFX28978 series, LFX25978 series Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual