LG LRTBC2021W, LRTBC1821W Owner’s Manual

SERVICING PRECAUTIONS

AIR RECHARGING IN COMPRESSOR
Test the refrigeration system connecting it electrfaally before

refilling operation. It is necessary to ascertain the function
of the motor*compressor and identity the defects

immediately, if defects have been found, empty the old
system of possible R-134a residue by breaking off the end

of the extension piece at its narrow point. (Figure 1)

Replace the filter and any damaged components. Unsolder
and pull off the piece remaining inside the service tube and
then attach an complete extension with male Hansen and

at last, solder it to the same tube again. (Figure 2)

POINT TO BE BROKEN

SERVICE TUBE EXTENSION

Figure I

It is necessary to executethe soldering operation with

valve open so that the fumes caused by oil residue can

come out freely without blowholes between two tubes

during the heating the of the point to be soldered.

The extension fitted with the male Hansen is connected to

the female fitting of the vacuum pump tube. (Figure 3)

CHARGE TUBE FEMALE
EXTENSION RANSEN

MALE HANSEN

SOLDERING POINT

Figure 2

vacuum operation is over, add the quantity in grams of
R-134a to the refrigeration system. Remember that every
system has an exact quantity of R-134a that can be added
with a tolerance of +5 grams. (Figure 4)

TO THE R-t34a CYLINDER

1

SYSTEM

TO THE REFRIGERATION

1

Before performing this operation (if the vacuum pump and

refilling cylinder are connected), make sure that the valve
placed between the vacuum pump and the refilling tube is

dosed in order to keep the Freen for addition to the system.
(Figure 5)

FILLING OR VALVE TO BE OPENED

CHARGE TUBE WHEN REFILLING

r_;_-- _J Figure 4

L3_

GAUGE

Air evacuating from the system begins as soon as the
pump starts. The refrigeration system must be kept under
vacuum until the reading on the low-pressure gauge
indicates vacuum (0 absolute, -1 aim., -760 mm hg). In any
case it is advisable to keep the pump running for about 30
minutes. (Figure 3)

If considerable leakage occurs, it will be necessary to stop
the vacuum pump and to add a small quantity of Freon to
the system. If vacuum should not be obtained (pressure
gauge can't fall to 1 atmosphere), start the refrigeration
unit and find the leakage with special leak-finder. When the
defective soldering point is visible, repair it after opening
the extension tube valve and reestablishing the normal
outside pressure inside the group.

Because the melted alloy is sucked into the tubes and
blocks them, the pressure must be rebalanced when
vacuum is in the system when soldering, As soon as the

TO THE REFRIGERATION TO THE CHARGE

SYSTEM CYLINDER

VALVE TO BE CLOSED
AFTER VACUUM

TO THE
VACUUM _ Figure 5

PUMP

In addition, check the graduated scale on the cylinder for

the quantity of R-134a to be added, for example, ifwe have
750 grams of Freon in the cylinder and must add 140
grams to the group, this amount will be reached when

R-134a has dropped to 610 grams, remembering thai the
indicator shows a lower limit of meniscus. Do this after

choosing the scale corresponding to the gas pressure
different scales reported as the same gas pressure

indicated by the pressure gauge on the top of the column.
To make R-134a flow i_o the system, open the valve

placed at the base of the cylinder connected to the filling
tube. The amount of Freen cannot be added to the system
all at once because it may cause a blocking of motor-
compressor. Therefore, proceed by adding the original
quantity of about 20-30 grams and close the valve

immediately.

The pressure rises and the motor compressor must start
sucking the gas and lowering the pressure again. Open the
valve again, maintaining the same manner until reaching to
the quantity of R-134a established for the system being

charged. When the system is running, the suction pressure

must be stabilized between 0.30 to 0.6 (0.10 to 0.4)

atmosphere.

-3-

T

2001.06.01 1601120

CIRCUITDIAGRAM

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8W1 SW2 5W_

OFF OFF OFF 10.5 s_

ON OFF OFF 9 8eC

OFF ON OFF 10 se_

ON ON OFF 11 SeC

OFF OFF ON 12 sec

ON OFF ON 13 sec

OFF ON ON 14 sec

ON ON ON 15sec

WITCHOFF 2 3

SWI SW2 SW3

TIME

ON

2. PARTS IDENTIFICATION

FREEZER

COMPARTMENT

Freezer Shelf

Automatic Ice Maker

Ice Cube Box

Freezer Temperature

REFRIGERATOR

COMPARTMENT

Push the grilletoward

Control Dial

Temperature

Control Dial

Lamp

Shelves

Egg Box

Snack Comer

Crisper

Used to keep fruits

and vegetables

fresh and crisp.

Base Grille

the refrigerator

until it snaps

into place.

Freezer Door Bin

Door Cooling
On the refrigerator door,
the cold air passageway is
installedto supply

coldair to the doorside of
the refrigerator

compartment.

Can Server

Dairy Corner
Wine Rack
Adjustable

Door Bin

Refrigerator Door
Rack

Leveling Screw
(Inside)

-5-

3. DISASSEMBLY

3-1 DOOR

• Freezer Door

1. Remove the hinge cover by pulling it upwards.

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

HINGE COVER

HINGE
BOLT

Figure 6

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

GASKET

3-2 DOOR SWITCH

1. To remove the door switch, pull out it with a slotted type
driver as shown in (figure g).

2. Disconnect the lead wire from the switch.

LEAD WIRE

DOOR SWITCH

Figure 9

3-3 THERMOSTAT

1. Remove Control Box-R by loosening 2 screws attached to
ceiling of Refitgerator comparb'nent (Figure 10)

2. Separate the thermostat and dial knob F.

3. Remove the thermostat by disconnecting the lead wire.

Figure 7

• Refrigerator Door

1. Loosen hexagonal bolts attaching the lower hinge to the
body to removethe refrigeratordoor only.

_:_ LOWER HINGE

BOLT

Figure 8

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

Figure 10

-6-

3-4 FAN AND FAN MOTOR

1. Remove the freezer shelf. (If your refrigerator have an
Ice Maker, disassemble the Ice maker first)

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

3. Remove the Fan Motor assembly by loosening 4 screws
and disassemble the shroud.

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

3-6 REFRIGERATOR ROOM LAMP

REFRIGERATOR ROOM LAMP

Figure 16

SHROUD

Figure 12

3-5 DEFROST CONTROL ASSEMBLY

Defrost control assembly consists of Defrost Thermostat

and FUSE-M.

Defrost Thermostat functions to defrost automatically and it
is attached to metal side of the Evaporator and senses

Temp.

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

At the temperature of 77°C, it stops the emission of heat

from the Heater.

1. Pull out the grille assembly.

2. Separate the connector connected with the Defrost
Control assembly and replace the Defrost Control

assembly after cutting the Tie Wrap. (Figure 14)

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 original.

(Max 40 W)

3-7 CONTROL BOX-R

1. First, remove all shelves in the refrigerator and Control
Box-R by loosening 2 screws.

1

COVER LAMP_@ Figure 17

2. Remove the Control Boxer by pulling it downward.

3. Disconnect the lead wire on the right pusibon and
seperate timer, themostat, Lamp socket, etc.

SHROUD-F

Figure 13

DEF-THERMO

FUSE-M

HOLDER FUSE Figure 14

-7-

4. ADJUSTMENT

_ICOMPRESSOR

4-1-1 Role
The compressor intakes low temperature and low pressure

gas evaporated from evaporator of the refrigerator, and

condenses this gas to high temperature and high pressure
gas, and then plays delivering role to condenser.

4-1-2 Composition
The compressor includes overload protection. The PTC

starter and OLP (overload protector) are outside the
compressor. Since the compressor is manufactured to

tolerances of 1 micron, and is 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-currant.
(2) No Strike

If applying forcible power or strike (dropping or careless
handling), poor operation and noise may occur.

(3) Use proper electric components eppmpdata to the

Compressor.

(4) Note to Keep Compressor.

if Compressor gets wet in the rain and rust in the pin of
Hermetic Terminal, the result may be poor operation

and poor contact may cause.

(5) Be careful that dust, humidity, and welding flux don't

contaminate the compressor inside when replacing the
Compressor. Dust, humidity, and flux due to welding

which contaminates the cylinder may cause Iockege
and noise.

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
matedal consisting of 8aTiO3.

(2) The higher the temperature is, the higher the resistance

value. These features are used as starting device for
the Motor,

4-2-2 Role of PTC-Starter
(1) PTC is attached to Hermetic Compressor used for

Refrigerator, Show Case, and starting Motor.

(2) Compressor for household refrigerator applies to

single-phase induction Motor.
For normal operation of the single-phase induction

motor, in the starting operation flows in both main coil
and sub-coil. After the starting is over, the current in

subcoil is cut off. The proper features of PTC play all
the above roles. So, PTC is used as a motor starting

device.

4-2-3 PTC-Appltad Circuit Diagram

• According to Starting Method for the Motor

OVERLOAD PROTECTOR(O.L.P)

-=_ C
[-- _-C -] ,= /_'_ COMPRESSOR

PTC STARTER HERMETIC

RSlR

4-2-4 Motor Restarting and PTC Cooling
(1) For restarting after power off during normal

Compressor Motor operation, plug the power cord after

5 rain. for pressure balance of Refrigerating Cycle and
PTC cooling.

(2) During normal operation of the Compressor Motor, PTC

elements generate heat continuously. Therefore,
if PTC isn't cooled for a while after the power has been
shut off, the motor will not restart.

4-2-5 Relation of PTC-Starter and OLP
(1) If the power is off during operation of Compressor and

the power is on before the PTC is cooled, (instant shut-
off within 2 min. or unplugging and reconnecting), the

PTC isn't cooled and a resistance value grows. As a
result, current can't flow to the sub-coti, the Motor con't

operate, and the OLP operates by flowing over currant

in only in the main-coil.

(2) While the OLP repeats on and off operation about 3-5

times, PTC is cooled and Compressor Motor performs

normal operation.
If OLP doesn't operate when PTC is not cooled,

Compressor Motor is worn away and causes circuit-
short and tire. Therefore, always use a properly

attached OLR

4-2-6 Note to Use PTC-Starter

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

Don't apply a forcible power or strike.

(3) Keep apart from any liquid.

If liquid, such as oil or water away enters the PTC,

PTC materials may fail due to insulation breakdown of

the material itself.

(4) Don't change PTC at your convenience.

Don't disassemble PTC and case. If the exterior to the

PTC-atarter is damaged, resistance value is altered and

it may cause poor starting of the compressor motor may
cause.

(5) Use a properly attached PTC.

TERMINAL

Figure 19

-8-

4-30LP (OVERLOAD PROTECTOR)
4-3-1 Definition of OLP

(1) OLP (OVERLOAD PROTECTOR) is attached to the

Compressor and protects the Motor by cutting the
current to the Motor ifthe temperature rises and

activates the bimetal spring in the OLP.

(2) When over-voltage flows to Compressor motor, the

Bimetal works by heating the heater inside the OLP,

and the OLP protects Motor by cutting off current which
flows to the Compressor Motor.

4-3-2 Role of the OLP
(1) The OLP is attached to the Hermetic Compressor used

for the Refrigerator and prevents the Motor Coil from

being started inthe Compressor.

(2) Do not turn the Adjust Screw of the OLP in any way for

normal operation of the OLR
(Composition and connection diagram of OLP)

5. CIRCUIT DIAGRAM

CONTACTING
POINT

SCREW

ADJUST _

COVER

BIMETAL

BIMETAL

HEATER

[ i co.=]

Figure 21

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I_"_: Ple=emplu9thepo_r =_1

fromthev_loulef.

SWg'(_N0

awl SW3

OFF OFF 10.5Se

ON OFF 9 sec

OFF OFF lOsec

ON OFF 11se(

OFF O_ 12se(

ON ON 13se(

OFF ON 14se{

SWITCHOFF 2 3

L_J L-_J _

SW1SW2 SW3

TIME

15see

3854JD1046C

-9-

6. TROUBLESHOOTING

6-1 COMPRESSOR AND ELECTRIC COMPONENTS

.._ Remove the PTC-

[_ [ Power Source.

Starter from the
Compressor and

measure the voltage
between Terminal C of

Compressor and
Terminals 5 or 6 of PTC.

)_No Voltage. _ OLP disconnected?

._ (Rating Voltage YES

_+10%)? I "[_

Replace OLR

condition.
Check connection __]

L_ Reconnect. I

Check the
resistance of

Motor

Compressor.

Check the

resistance of
PTC-Starter.

Check OLR

Check

starting state.

_. in the range of Rating ,_to use a regular _,

Voltage ±10%. | transformer.

_ heck the resistance

amongM-C, S-C and
M-S in Motor

Compressor.

of two terminals in

-_ heck the resistance

PTC-Starter.

a regular OLR _ [30 sec. in forcible OLP

_._ Check if applying _,,10LP works within ___ YES i .[_

NO t_"

_ Replace Compressor.

YEs

NO _- Replace

YES

I I Ioperation by turning Replace OLR

I I instant power on and

I

PTC-Starter.

II°" f

NO

starting voltage after 5
rain, for balancing cycle
pressure and cooling the

]_ easura minimum ___

PTC.

the voltage of Rating
Voltage _+10%

Components start in _-_ O.K. I
below. NO _-[_

-10-

6-2 PTC AND OLP

11

Normal operation of

Compressor is -_
impossible or poor.

/

Separate the PTC-
Starter from

Compressor and

measure the
resistance between

No. 5 and 6 of PTC-
Starter with a Tester or

Wheatstone Bridge.
(Figure 21)

-]P

Compressor and check I Vl electric components. I
the resistance value I I

between two terminals J r

I Separate the OLP freml YES_[ Check another

of OLP with a Tester. _ I

(Figure 22) _ Replace OLR

._}1_ Observation value is _ Check another |

220VISOHz: 22_±30% electric components, I

115V/60Hz : 6.8__+30%

240VI50 HZ: 33_±30%

127.220V!60Hz : 22_
±30%

is 0 or several Starter I
hundred _.

The value is _o.

=

=

!

6-3 DEFROST TIMER

Normal operation of

the Defrost Timer is
impossible.

No defrosting.

Poor cooling.

_/Fl'igure 21_igure 22

the point of first click

sound and check the
Position the Cam Shaft to

current flowing between

terminals No. t(brown)

and No. 2(boght orange).

I__ Next, posi0on the Cam

__ No. 1 (brown) and

Shaft to the point of
second click sound and

check the current flowing
between terminals

No. 4 (black)
(Figure 23).

-_ Turn the Cam Shaft.

-_ with holding the Cam

f Shake about 3 times

Shaft and Body softly.

_--_ The resistanceis _. t_ DRePlroa_tethmeer. I

._The resistance is

0_2or variable.

220V/50Hz :2OK.Q

The resistanceis about

115V/60Hz :7.8K&_

I "°

-_ Loud click sound,

I__ Replace the

Defrost Timer. I

_ Check the another ]

electric components. I

Replace the
Defrost Timer.

Defrost Timer.

Replace the I

Figure 23

-11 -