LG LRTPC2031T, LRTPC1831T Owner’s Manual

SERVICING PRECAUTIONS

AIR RECHARGING IN COMPRESSOR

Test the re_geration system connecting it electrically before

refilling operation. It is necessary to ascertain the function

of the motor-compressor and identify the defects

immediately. If defects have been found, empty the old
system of possible R-134a residue by breaking off the end
oftha 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 1

It is necessary to execute the 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)

CHARGETUBE FEMALE
EXTENSION HANSEN

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 +-5grams. (Figure 4)

TO THE R-134a CYLINDER

_ _ TOTHEREFRIGE_T_ON

SYSTEM

_-_ t Figure 4

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
closed in order to keep the Freon for addition to the system.
(Figure 5)

FILLING OR VALVE TO BE OPENED
CHARGE TUBE WHEN REFILLING

. VACUUM

Air evacuating from the system begins as soon as the
pump starts. The refrigeration system must be kept under
vacuum untti the reading on the low-pressure gauge
indicates vacuum (0 absolute, -1 stm., -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, ff 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
bicoks them, the pressure must be rebalancod when
vacuum is in the system when soldering. As soon as the

THE

PRESSURE

GAUGE

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, if we
have 750 grams of Freen 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 that the

indicator shows a lower limitof 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-t34a flow into 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 Iowedng 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-

160/120

CIRCUITDIAGRAM

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Siall;tl No

SWI SW2 SWI
OFF OFF OFF 10,5

ON OFF OFF 9 86_

OFF ON OFF 10$ec

ON ON OR= 11SeC

OFF OFF ON 12 $_C

ON OFF ON 13 sec

OFF ON ON 14 sec

ON ON ON 15sec

r'-_ r--] _-1

_WlI_4 OFF t. 1 2 3

L-iJ _ Li-J

SW1 _ SW3

TIME

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3854JD1046C

2. PARTS IDENTIFICATION

FREEZER

COMPARTMENT

Freezer Shelf

Automatic Ice Maker

Ice Cube Box

Freezer Temperature

Control Dial

REFRIGERATOR

COMPARTMENT

Temperature

Control Dial

Lamp

Shelves

Egg Box

Snack Comer

Crisper

Used to keep fruits

and vegetables

fresh and crisp.

Lamp

Freezer Door Bin

Door Cooling
On the refrigeratordoor,
the cold air passageway is
installedto supply

coldairto the doorsideof
the refrigerator

compartment.
Egg Tray

Can Server

Dairy Comer
Can Storage

ustable

Door Bin

Refrigerator Door
Rack

Base Grille

Pushthe grilletoward

the refrigerator

untilit snaps

intoplace.

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.

BOLT

_. HINGE COVER

3. PuN out the door gasket to remove from the door foam

assembly.

HINGE

Figure 6

GASKET

3-2 DOOR SWITCH

1. To remove the door switch, pull out itwith 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 Contral Box-R by loosening 2 scre,,_ attached to
ceiling of Refrigerator compadrnent (F_gure10)

2. Separate the thermostat and dial knob E

Remove the thermostat by disconnecting the lead wire.

Figure 7

• Refrigerator Door

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

LOWER HINGE

BOLT

__J

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 end Bracket.

SHROUD

_\._FAN MOTOR

FAN

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)

3-6 LAMP

REFRIGERATOR ROOM LAMP

Figure 16-1

3-6-1 Refrigerator room 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 ofiginak

(Max 40 W)

FREEZER ROOM LAMP

Figure 16-2

3-6-2 Freezer room lamp

1. Unplug refrigerator or disconnect power.

2. Reach behind light shield to remove bulb.

3. Replace bulb with a 25-watt appliance bulb.

4. Plug in refrigerator or reconnect power.

3-7 CONTROL BOX-R
1, First, remove all shelves in the refrigerator and Control

Box-R by loosening 2 screws.

SHROUD-F

L__. ,_ Figure 13

DEF_HERMO

FUSE-M

HOLDERFUSE Figure 14

I

COVER LAMP_@ Figure 17

2. Remove the Control Box-R by pulling itdownward.

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

-7-

4. ADJUSTMENT

4-1 COMPRESSOR

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 ovedoad protection. The PTC
starter and OLP (overload protector) are outside the

compressor. Since the compressor is manufactured to
tolerances of I 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*current.

(2) No Stdke

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

(3) Use proper electnc components appropriate 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 operetlen

and poor contact may cause.

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

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

which contaminates the cylinder may cause Iocknge

and noise.

4-2 PTC-STARTER

4-2-1 Composition of PTC-Starter
(1) PTC (Positive Temperature Coefficient) is a no-contaet

semiconductor starting device which uses ceramic
material consisting of BaTiOs.

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

value. These features am used as starting device for

the Motor.

4-2-2 Role of PTC-Starter

(1) PTC is attached to Hermetic Compressor used for

Refdgeretor, Show Case, and starting Motor.

(2) Compressor for household refrigerator applies to

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

motor, in the starting operation flows in both main coil
and sub-coiL After the starting isover, 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)

o

F -75 cog ESSOR

PTC STARTER HERMETIC

RSIR

4-24 Motor Restarting and PTC Cooling

(1) For restarting after power off dudng normal

Compressor Motor operation, plug the power cord after
5 min. for pressure balance of Refdgerafing Cycle and

PTC cooling.

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

elements generate heat cot_inuously. 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

(I) If the power is off dudng 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-coil, the Motor can_
operate, and the OLP operates by flowing over current

in only in the main-coil.

(2) While the OLP repea_ 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 fire. Therefore, always use a properly

attached OLP.

4-2-6 Note to Use PTC-Starter

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

(2) Do not stdke

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'[ disassemble PTC and case. If the exterior to the

PTC-starter 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 cuttingthe

current to the Motor if the temperature rises and
activates the bimetal spring in the DLP.

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

Bimetal works by hea_ing 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 DLP is attached to the Hermetic Compressor used

for the Refrigerator and prevents the Motor Coil from

being started in the Compressor.

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

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

5. CIRCUIT DIAGRAM

CONTACTING

POINT

COVER

_ _ BIMETAL

SCREW

ADJUST

HEATER

BIMETAL

Figure 21

CIRCUITDIAGRAM

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WATI_ISBPPLYI__ _If_ROL
OPTION

• C_UIION:Phaseumlugth*l:_Wo_
lTor_Ih8walloulel.

5'_T(_ND

SW1 SW2 SW3
OFF OFF OFF 10.5=

ON OFF OFF 9 sec

OFF ON OFF 10S_

ON ON OFF 11se

OFF OFF ON 12S_

ON OFF ON 13S_

OFF ON ON 14s_

ON ON ON 15S_

SWITCHOFF 2 3

L_.J _ _

SWl sw2 sw3

TIME

3854JD1046C

-9-

6. TROUBLESHOOTING

6-1 COMPRESSOR AND ELECTRIC COMPONENTS

Remove the PTC-

[_ I 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 OLP.

condition.

Check conneclton __]

Reconn I

_,. in the range of Rating ,I to use a regular

VO rage ±10%. i transformer.

Check the _ Check the resistance

Motor M-S in Motor
resistance of i ° I among M-C, S-C and

Compressor. Compressor.

Check the _- Check the resistance

PTC-Starter. PTC-Starter.

resistance of i I of two terminals in

[_ _ Check if applying

[_ Check

Check OLP. a regular OL_

starting state.

_ F

starting voltage after 5 i I the voltage of Rating " "

min. for balancing cycle i I Voltage -+10%

_ Measure minimum _-_ Components start in _-_ O K

PTc.pressureand cooling the I Lbelow. J NO

I

N_O YES _- [3[3[3_

Replace Compressor.

Replace

NO _- PTC-Starter.

YES

30 sec. in forcible OLP

operation by turning Replace OLP.

instant power on and

_ LP w°rks within _ YES i _'[_

Off. f

NO

I

I

-10-

6-2 PTC AND OLP

Normal operation of t'_

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)

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

between two terminals I
Separate the OLP from] YES_ Check another
of OLP with a Tester. _ I

(Figure 22) _ Replace OLP.

Observation value is
220V/50Hz : 22_30%
115V/60Hz : 6 8_,E1:30%

240V/50Hz :33.(Z_30%

127,220VI60Hz : 22_)

-+30%

The resistance value
is 0 or several
hundred _.

The value is _.

Check another Ielectric components.

Replace PTC-

Starter

I

I

6-3 DEFROST TIMER

the Defrost Timer is

Normal operation of

impossible.

No defrosting.

Poor cooling.

--]P the point of first click

sound and check the
current flowing between

terminals No. 1(brown)
and No, 2(bright orange).
Position the Cam Shaft to

Next, position the Cam
Shaft to the point of

second click sound and
check the current flowing

between terminals

No. 4 (black)

.__ NO. 1(brown) and

(Figure 23).

-}_ Turn the Cam Shaft.

-}P with holding the Cam
I Shake about 3 times

Shaft and Body softly.

..-_ The resistance is ,_.

0Q or variable.

.Y_ The resistance is

220VISOHz: 20K_

__Tbe resistanceisabout

115V/60Hz: 7.8K_

I N°

I_ Loud clicksound.

-11 -

I ;eefp °acstethmeer.I

I_t Checkthe another I

Figure 23

electric components. I

7-- Replace the

Defrost Timer. I

I