LG LBC20514TT Service Manual

REFRIGERATOR

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE PRODUCT,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

MODELS:

LBC20514TT

CONTENTS

Safety Precautions………………………………………………................................ 2

1- Specifications…………………………………………………................................ 3

2- Parts Identifications …………………………………………................................ 4

3- Disassembly……………………………………………………............................... 5 Door……………………………………………………………................................... 5 Door Switch……………………………………………………...................................5 Fan and Fan Motor……………………………………………..................................6 Defrost Control Assembly ……………………………………..................................6 Lamp……………………………………………………………..................................6 Refrigerator Control Box……………………………………….................................6 Multi Duct……………………………………………………….................................. 6

4- Ajustment……………………………………………………....................................7

Compressor…………………………………………………….................................. 7

PTC-Starter…………………………………………………….................................. 7

OLP (Overload Protector)…………………………………….................................. 8

To Remove the Cover PTC………………………………….................................. 8

5- Circuit Diagram……………………………………………..................................... 9

6- Troubleshooting……………………………………...................................……….10 Compressor and Electric Components…………………....................................…10 PTC and OLP …………………………………………....................................…….11

Other Electrical Components………………………….....................................……12

Service Diagnosis Chart……………………………....................................………13

Refrigeration Cycle…….………………………………....................................……14

7- Operation Principle and Repair Method of Ice Maker….................................16

8- Description of Function and Circuit of MICOM……….............................……19

11Refrigerator Exploded View …....................................................................... 38

SAFETY PRECAUTIONS

	Pleasereadthefollowinginstructionsbeforeservicingyour
	refrigerator.
	1.Checktherefrigeratorforcurrentleakage.	7.Beforetiltingtherefrigerator,removeallmaterialsfrom
	2.Topreventelectricshock,unplugbeforeservicing.	onorintherefrigerator .
	3.Alwayschecklinevoltageandamperage.	8.Whenservicingtheevaporato,rwearglovestoprevent
		injuriesfromthesharpevaporatorfins.
	4.Usestandardelectricalcomponents.
		9.Serviceontherefrigeratorshouldbeperformedbya
	5.Don'ttouchmetalproductsinthefreezerwithwet
		qualifiedtechnician.Sealedsystemrepairmustbe
	hands.Thismaycausefrostbite.
		performedbyaCFCcertifiedtechnician.
	6.Preventwaterfromspilingontoelectricelementsorthe
	machineparts.

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1. SPECIFICATIONS

Specification

Color

Capacity

Dimensions (in)

Refrigerant

Climate Class

Control Type

Rating

Case Material

Door Material

Reversible Door

Lamp (F)

Lamp ( R )

Basket (F)

Basket ( R )

Shelf (F)

Shelf ( R )

Cover, TV

Drawer

Vegetable

Tray Meat

Multi Flow

Models

LBC20514TT

Titanium

20cuft

29.8 (W) x 32.2 (D) x 67.9 (H)

R134A (4.2oz)

Temperate(N)

F-control

115/60

EMBO(Normal)

VCM

Yes

1(40W/Blue)

2(40W/Blue)

1(plastic) 2 (1/3) 2 (2/3) 1 full

1 Wire

4 fix

Humidity Control

Wire (lower)

Yes

Yes

Yes

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2. PARTS IDENTIFICATIONS

A
B	I
C	J
D
	K
E	L
F	M
G
H
	N

Use this section to become more familiar with the parts and features.

NOTE:This guide covers several different models.The refrigerator you have purchased may have some

or all of the items listed below.The locations of the features shown below may not match your model.

	A	Digital Sensor Control	I	Dairy Bin
	B	Refrigerator Light	J	Design-A-Door
	C	Shelves	K	Wire Freezer Shelf
	D	Snack Pan	L	Refrigerator Door Rack
	E	Optibin Crisper	M Freezer Light
		Keeps fruits and vegetable fresh and crisp	N Freezer Door Rack
	F	Ice Tray*
			*on some models

GIce Bin

HWire Durabase

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3. DISASSEMBLY

3-1 DOOR

Refrigerator Door

1.Remove the hinge cover by pulling it upwards.

2.Loosen the hexagonal bolts attaching the upper hinge to the body and lift the freezer door.

HINGE COVER

BOLT

HINGE

Figure 1

3.Pull out the door gasket to remove from the door foam assembly.

GASKET

Figure 2

Freezer Door

1.Loosen the hexagonal bolts attaching the lower hinge to the body to remove the refrigerator door only.

LOWER HINGE

BOLT

Figure 3

2.Pull out the door gasket to remove from the door foam assembly.

3-2 DOOR SWITCH

1.To remove the door switch, pry it out with a slotted-type driver, as shown in (Figure 4).

2.Disconnect the lead wire from the switch.

LEAD WIRE

DOOR SWITCH

Figure 4

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3-3 FAN AND FAN MOTOR

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

2.Remove the grille by pulling it out and by loosening a screw.

3.Remove the Fan Motor assembly by loosening 2 screws and disassemble the shroud.

4.Pull out the fan and separate the Fan Motor and Bracket.

5.Pull out the fan and separate the Fan Motor and Bracket.

FAN MOTOR

BRACKET

MOTOR

FAN

Figure 11

GRILLE

3-4 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.

Fuse-M is a safety device for preventing over-heating of the Heater when defrosting.

At 72°C, it turns the Defrost Heater off.

1.Pull out the grille assembly. (Figure 6)

2.Separate the connector with the Defrost Control assembly and replace the Defrost Control assembly after cutting the Tie Wrap. (Figure 7)

GRILLE ASSEMBLY

DEFROST-CONTROL

ASSEMBLY

Figure 6

Figure 7

3-5 LAMP

Figure 8

3-5-1 Refrigerator Compartment Lamp

1.Unplug the power cord from the outlet.

2.Remove refrigerator shelves.

3.Release the hooks on both ends of the lamp shield and pull the shield downward to remove it.

4.Turn the lamp counterclockwise.

5.Assemble in reverse order of disassembly. Replacement bulb must be the same specification as the original (Max. 60 W-2EA).

Figure 9

3-5-2 Freezer Compartment Lamp

1.Unplug refrigerator or disconnect power.

2.Reach behind light shield to remove bulb.

3.Replace bulb with a 60-watt appliance bulb.

4.Plug in refrigerator or reconnect power.

3-6 CONTROL BOX-REFRIGERATOR

1.First, remove all shelves in the refrigerator, than remove the Refrigerator control Box by loosening 2 screws.

CONTROL BOX

COVER LAMP

Figure 10

2.Remove the Refrigerator Control Box by pulling it downward.

3.Disconnect the lead wire on the right position and separate the lamp sockets.

3-7 MULTI DUCT

1. Remove an upper and lower Cap by using a flat screwdriver, and loosen 3 screws. (Figure 11)

2. Disconnect the lead wire on the bottom position.

Figure 11

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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 Composition

The compressor includes overload protection. The PTC starter and OLP (overload protector) are attached to the outside of the compressor. Since the compressor is manufactured to tolerances of 1 micron and is hermetically sealed in a dust and moisture-free environment, use extreme caution when repairing it.

4-1-3 Note for Usage

(1)Be careful not to allow over-voltage and over-current.

(2)If compressor is dropped or handled carelessly, poor operation and noise may result.

(3)Use proper electric components appropriate to the Particular Compressor in your product.

(4)Keep Compressor dry.

If the Compressor gets wet (in the rain or a damp environment) and rust forms in the pin of the Hermetic Terminal, poor operation and contact may result.

(5)When replacing the Compressor, be careful that dust, humidity, and soldering flux don’t contaminate the inside of the compressor. Dust, humidity, and solder flux contaminate the cylinder and may cause noise, improper operation or even cause it to lock up.

4-2 PTC-STARTER

4-2-1 Composition of PTC-Starter

(1)PTC (Positive Temperature Coefficient) is a no-contact semiconductor starting device which uses ceramic material consisting of BaTiO3.

(2)The higher the temperature is, the higher the resistance value. These features are used as a starting device for the Motor.

4-2-2 Role of PTC-Starter

(1)The PTC is attached to the Sealed Compressor and is used for starting the Motor.

(2)The compressor is a single-phase induction motor. Durign the starting operation, the PTC allows current flow to both the start winding and main winding.

4-2-3 PTC-Applied Circuit Diagram

Starting Method for the Motor

	OVERLOAD PROTECTOR
	N		C
	PTC	5	COMPRESSOR
	2		MOTOR
		S	M	M
			S
	3	6
	L1
	PTC STARTER		SEALED
			TERMINAL
	Resistance Starter Capacitor Running

Figure 12

4-2-4 Motor Restarting and PTC Cooling

(1)It requires approximately 5 minutes for the pressure to equalize before the compressor can restart.

(2)The PTC device generates heat during operation. Therefore, it must be allowed to cool before the compressor can restart.

4-2-5 Relation of PTC-Starter and OLP

(1)If the compressor attempts to restart before the PTC device is cooled, the PTC device will allow current to flow only to the main winding.

(2)The OLP will open because of the over current condition. This same process will continue (3 to 5 times) when the compressor attempts to restart until the PTC device has cooled. The correct OLP must be properly attached to prevent damage to the compressor.

Parts may appear physically identical but could have different electrical ratings. Replace parts by part number and model number. Using an incorrect part could result in damage to the product, fire, injury, or possibly death.

4-2-6 Note for Using the PTC-Starter

(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 PTC,

PTC materials may fail due to breakdown of their insulating capabilities.

(4)If the exterior of the PTC is damaged, the resistance value may be altered. This can cause damage to the compressor and result in a no-start or hard-to-start condition.

(5)Always use the PTC 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. Using an incorrect part could result in damage to the product, fire, injury, or possibly death.

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4-3 OLP (OVERLOAD PROTECTOR)

4-3-1 Definition of OLP

(1)OLP (OVERLOAD PROTECTOR) is attached to the Compressor and protects the Motor by opening the circuit to the Motor if the temperature rises and activating the bimetal spring in the OLP.

(2)When high current flows to the Compressor motor, the Bimetal works by heating the heater inside the OLP, and the OLP protects the Motor by cutting off the current flowing to the Compressor Motor.

4-3-2 Role of the OLP

(1)The OLP is attached to the Sealed Compressor used for the Refrigerator. It prevents the Motor Coil from being started in the Compressor.

(2)For normal operation of the OLP, do not turn the Adjust Screw of the OLP in any way.

(OVERLOAD PROTECTOR cross section)

Part

		Customer part
	12345678	number
		Lot code/
330 FBYY	-S1 BOX98	date code
Electrical		Physical
characteristics		termination
part number		part number

No. Name

Base, phenolic (UL 94 V-0 rated)

Movable arm support, plated steel

Stationary contact support, plated steel

Heater support, plated steel

Heater, resistance alloy

Disc, thermostatic alloy

Movable arm, spring temper copper alloy

Contact, movable, silver on copper

Contact, stationary, silver on copper

Slug, plated steel

Cover, polyester (UL 94 V-0 rated)

Pin connector, plated copper alloy (To engage 2.33/2.66 mm dia. pin) Quick-connect terminal, brass, conforms to UL 310, MEMA

DC-2, DIN 46344

Figure 13

4-4 TO REMOVE THE COVER PTC

1) Remove the Cover Back M/C.

(2) Remove the screw on Cover PTC.

1

(3)Remove two Housings on upper part of Cover PTC.

(4)Take out the cover PTC from upper to lower position like ( 1 ).

2

(5)Turn 45¡ in the direction of (2)and take it out.

(6)Assembly in reverse order of disassembly.

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5. CIRCUIT DIAGRAM

														PWB(PCB) ASSEMBLY,DISPLAY
													CON101				1		2		3		4		5		6		7		8			9
																	WH		BO		BL		SB		PR		BK		PK		WH		YL																S/W
																	/RD				/WH
																																															DOOR-R		PERCEPTION
		F-FAN					STEPPING
								MOTOR
																																															C		D
PR			GY		WH		BL		BK		YL		RD				/RDWH		BO		/WHBL		SB												PR		BK		PK		WH				YL		GY		GY
1			2		3		4		5		6		7		8	9	10		11		12		13					1		2		3			4		5		6		7		8	9	10		11		12
CON4																											CON5

PWB(PCB) ASSEMBLY, MAIN

L1

11 10

9

8

7

6

5

4

3

2

1

7

6

5

4

3

2

1

POWER

SB

BN

YL

BL

BL

BK

BN

RD

SB

SUPPLY

CON1

CON2

CORD

SB

BN

YL

BL

BL

BK

BN

RD

SB

N

L

GN/YL

(GN)

BK

BK

ICE MAKER PART

GN/YL

FUSE-M

(98C)

(GN)

SENSORICE

HEATER, SHEATH

M

MAKERICE MOTOR

BK POWER

S/W

I/MAKER

W/VALVE

CAPACITOR PART

OLP

-CFAN

Cs

4

5

S

Cr

PK

V

M

RD

2

CON5 2WH

WH1

CON4 WH1

WH1

CON3

CON2 BK2

WH1

CON1

BL2

1BK

CON6

1RD

BL

PTC STARTER

M

GN

/YL

BL

3

6

(GN)

COMP' EARTH

PART

PWB (PCB) ASSEMBLY, ICE MAKER

COMP' ACCESSORIES

		* ALTERNATIVE COMP' ACCESSORIES
		Cr	BK
	*PLUG TYPE, ICE MAKER PART, CAPACITOR PART,	BL	OLP	L
		N
	P.T.C START OPTION, COMP' EARTH PART AND COMP'
	ACCESSORIES ON CIRCUIT DIAGRAM ARE SUBJECT
	TO CHANGE IN DIFFERENT LOCALITIES AND MODEL TYPE.
		PTC
		COMBO KIT(PTC+OLP)

	CON6 1	PK	A	F-DOOR
	2	PK	B	PERCEPTION S/W
	3	BO	DEF-SENSOR
	4	BO
	5	WH	R-SENSOR
	6	WH
	7	BL	F-SENSOR
	8	BL

	S/W-F	com	com	S/W-R	com	com
FUSE-M (72 C)	DOOR	nc	nc	DOOR	nc	nc
	HEATER,SHEATH	A B	LAMP-F		C D	LAMPS-R
RD		BO			PR
BL		BL			BL
		* P.T.C START OPTION
	MC,MQ COMP'			EG COMP'

	2		3
4	5	4	6
3	6	2	5

MEZ48108403

BK:BLACK	WH:WHITE	BN:BROWN	BO:BRIGHT ORANGE	SB:SKY BLUE	RD:RED
YL:YELLOW	PK:PINK	GN:GREEN	PR:PURPLE	GY:GREY	BL:BLUE

- 9 -

6. TROUBLESHOOTING

6-1 COMPRESSOR AND ELECTRIC COMPONENTS

1

2

3

4

			Remove PTC-Starter		(Rated voltage	YES
Power Source.			from compressor and		±10%)?		2
			measure voltage
			between Terminal C of
			compressor and
			terminal 5 or 6 of PTC.

	YES		5
No voltage.	OLP disconnected?	Replace OLP.
	NO	Check connection
		condition.

Reconnect.

	Applied voltage isn't		Advise customer that		5
	in acceptable range.		power supply needs to be
	(115V ±10%)		checked by an electrician.

Check

Check resistance

resistance of of motor

motorpressorc.

compressor.

.

Check resistance of PTC-Starter.

Check OLP.

						The range of resistance is between 1~50				? (ok)
	Check the resistance									3
	between M-C, S-C and		Open or short			Replace
	M-S in motor compressor.
						compressor		3	4	5
	Check resistance of			Refer		to Page 12.
	two terminals in
	PTC-Starter.

		Check resistance of two				Refer	to Page 12.
		terminals in OLP.

Check

5

starting state.

Check the power supply

Supply

YES

Did

YES

Compressor

under load.

voltage rating

compressor

is OK

(Compressor attempting

with ±10%.

start?

to re-start after being off

Replace the

for 5 minutes).

NO

compressor

1

NO

- 10 -

6-2 PTC AND OLP

Normal operation of compressor is impossible or poor.

		Separate PTC-Starter		Observation value is
		from Compressor and		115V/60Hz : 6.8 ? ±30%
		measure resistance
		between No. 5 and 6
		of PTC-Starter with a
		Tester.
		(Figure 19)
				The resistance value
				is 0 ? (short) or
				8(open).

Replace PTC-

Starter.

	Separate OLP from		Shows continuity		Check another
	compressor and check				electric component.
	resistance value between
	two terminals of OLP whit a
	tester.		Open
	(Figure 20)				Replace OLP.

6

5

?

Figure 19

Figure 20

- 11 -

6-3 OTHER ELECTRICAL COMPONENTS

Not cooling at all

Compressor doesn't run.

Check for open short or

Cause

incorrect resistance readings in the following components

	a. Starting devices	Short, open, or broken.
	b. OLP	Poor contact
		or shorted.
	c. Compressor coil	Coil open or shorted.
	d.Wiring harness	Poor contact	Replace
		or shorted.	indicated component.
Poor cooling performance
Compressor runs	Check starting	Low voltage.	Advise customer that
poorly.	voltage.		the power supply
			needs to be checked
			by an electrician.

Check voltage at	Poor or broken or	Replace
starting devices.	open contact.	indicated component.

	Check current flowing		Shorted.
	in sub-coil of
	Compressor.

Check rating of OLP.

Lack of capacity.

	Fan motor	Check wiring circuit.	Wire is open or
	doesn't run.		shorted.
			Replace
			indicated component.
		Check Fan Motor.	Coil is shorted
			or open.

Heavy frost buildup on evaporator

Check current flow in	Open.	Replace
the following		indicated component.
components:
Sensor
Fuse-M
Check current flow in	Open.	Replace
the defrost heater.		defrost heater.

- 12 -

6-4 SERVICE DIAGNOSIS CHART

COMPLAINT	POINTS TO BE CHECKED	REMEDY
No Cooling.	•Is the power cord unplugged from the outlet?	•Plug into the outlet.
	•Check if the power switch is set to OFF.	•Set the switch to ON.
	•Check if the fuse of the power switch is shorted.	•Replace the fuse.
	•Measure the voltage of the power outlet.	•If the voltage is low, correct the wiring.
Cools poorly.	•Check if the unit is placed too close to the wall.	•Place the unit about 4 inches (10 cm) from the wall.
	•Check if the unit is placed too close to the stove,	•Place the unit away from these heat sources.
	gas cooker, or in direct sunlight.
	•Is the ambient temperature too high or	•Lower the ambient temperature.
	the room door closed?
	•Check if food put in the refrigerator is hot.	•Put in foods after they have cooled down.
	•Did you open the door of the unit too often	•Don't open the door too often and close
	or check if the door is sealed properly?	it firmly.
	•Check if the Control is set to Warm position.	•Set the control to Recommended position.
Foods in the	•Is food placed in the cooling air outlet?	•Place foods in the high-temperature section.
Refrigerator		(front part)
are frozen.	•Check if the control is set to colder position.	•Set the control to Recommended position.
	•Is the ambient temperature below 41°F(5° C)?	•Set the control to Warm position.
Condensartion or ice	•Is liquid food sealed?	•Seal liquid foods with wrap.
forms inside	•Check if food put in the refrigerator is hot.	•Put in foods after they have cooled down.
the unit.	•Did you open the door of the unit too	•Don't open the door too often and close
	often or check if the door is sealed properly?	it firmly.
Condensartion forms	•Check if the ambient temperature and humidity	•Wipe moisture with a dry cloth. It will disappear
in the Exterior Case.	of the surrounding air are high.	in low temperature and humidity.
	•Is there a gap in the door gasket?	•Fill up the gap.
There is abnormal	•Is the unit positioned in a firm and even place?	•Adjust the Leveling Screw, and position the
noise.		refrigerator in a firm place.
	•Are any unnecessary objects placed	•Remove the objects.
	in the back side of the unit?
	•Check if the Tray Drip is not firmly fixed.	•Fix the Tray Drip firmly in the original position.
	•Check if the cover of the compressor enclosure	•Place the cover in its original position.
	in the front lower side is taken out.
Door does not	•Check if the door gasket is dirty with	•Clean the door gasket.
close well.	an item like juice.
	•Is the refrigerator level?	•Position in the firm place and level the
		Leveling Screw.
	•Is there too much food in the refrigerator?	•Make sure food stored in shelves does not prevent
		the door from closing.
Ice and foods	•Check if the inside of the unit is dirty.	•Clean the inside of the unit.
smell unpleasant.	•Are foods with a strong odor unwrapped?	•Wrap foods that have a strong odor.
	•The unit smells of plastic.	•New products smell of plastic, but this
		will go away after 1-2 weeks.

Other possible problems:

Check if frost forms in the freezer.

Check the refrigeration system.

Check the

Thermistor.

Not

defrosting

The system

is faulty.

The operation of the Thermistor is

incorrect.

Check Components of the defrosting circuit.

Perform sealed system repair.

Replace the

Thermistor.

- 13 -