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Model
GR-122SJ
Pages
13
Size
246.69 KB
Type
PDF
Document
Service Manual
Brand
Device
Refrigerator
File
gr-122sj.zip
Date

LG GR-122SJ Service Manual ▷ View online

AIR RECHARGING IN COMPRESSOR
Test the refrigeration 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
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)
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)
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 atm., -760 mm hg) in any
case it is advisable to keep the pump running for about 30
minutes. (Figure 3)
In case that a considerable leakage occurs it will be
necessary to stop the vacuum pump and to add asmall
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 the special
leak-finder. When the defective soldering point is visible,
re-do 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
block them, the pressure must be rebalanced when
vacuum is in the system in soldering. As soon as the
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 with a tolerance of
±5 grams that can be added. (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 are
closed in order to keep the Freon for addition to the system.
(Figure 5)
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 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 that 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 into the system, open the valve
placed at the base of the cylinder and connected to the
filling tube. The amount of Freon 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. Regulate
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.
SERVICING PRECAUTIONS
- 3 -
POINT TO BE BROKEN
SERVICE TUBE EXTENSION
CHARGE TUBE
EXTENSION
FEMALE
HANSEN
MALE HANSEN
SOLDERING POINT
Figure  1
Figure  2
TO THE
VACUUM
PUMP
PRESSURE
GAUGE
Figure  3
TO THE R-134a CYLINDER
TO THE REFRIGERATION
SYSTEM
Figure  4
FILLING OR
CHARGE TUBE
VALVE TO BE OPENED
WHEN REFILLING
VALVE TO BE CLOSED
AFTER VACUUM
TO THE CHARGE 
CYLINDER
TO THE REFRIGERATION
SYSTEM
TO THE 
VACUUM
PUMP
Figure  5
COMPRESSOR AND ELECTRIC COMPONENTS
6. TROUBLESHOOTING
- 10 -
1
3
2
4
5
5
1
5
4
5
4
3
3
5
5
2
Power Source.
Remove the PTC-Starter
from the Compressor and
measure voltage between
Terminal C of compressor
and Terminal 5 or 6 of PTC.
No Voltage.
YES
YES
YES
NO
NO
NO
YES
YES
YES
NO
NO
YES
Rating Voltage ±10%?
Replace OLP.
Reconnect.
Replace
PTC-Starter.
Replace OLP.
O.K.
Check connection
condition.
OLP disconnected?
Advise the customer
to use regular TRANS.
Replace Compressor.
OLP works within
30 sec. in forcible OLP
operation by turning
instant power on and off.
Components start
in the voltage of Rating
Voltage ±10% below.
Applied voltage isn't
in the range of Rating
Voltage ±10%.
Check the resistance among
M-C, S-C and M-S
in Motor Compressor.
Check the resistance of
two terminals in PTC-Starter.
Check if applying
a regular OLP.
Measure minimum starting
voltage after 5 min. for
balancing cycle pressure
and cooling the PTC.
Check the
resistance of
Motor-
Compressor.
Check the
resistance of
PTC-Starter.
Check OLP.
Check
starting state.
PTC AND OLP
- 11 -
6
5
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 Tester or
Whistone Bridge(Figure 16).
Separate the OLP from
Compressor and check
resistance value between
two terminals of OLP with
Tester (Figure 17).
Observation value is
220V/50Hz : 33
±30%
110V/60Hz : 3.9
±30% 
The resistance value is
0 or serveral hundreds 
.
YES
NO
The value is 
.
Check another
electric components.
Replace OLP.
Check
another electric
components.
Replace
PTC-Starter.
Figure  16
Figure  17
+
-
Normal operation of the
Defrost Timer is
impossible.
No defrosting.
Poor cooling.
Position the Cam Shaft
to the point of first "click"
sound and check the current
flowing between terminals
No. 1(brown) and
No. 2(bright orange).
Next, position the Cam Shaft
to the point of second "click"
sound and check the current
flowing between terminals
No. 1(brown) and
No. 4(black).
(Figure 18).
Turn the Cam Shaft.
Shake about 3 times with
holding the Cam Shaft and
body softly.
The resistance is 
The resistance is
0
or variable.
The resistance is about
220V/50Hz : 13~17K
110-115V/60Hz : 6~10K
Loud "click" sound.
YES
NO
NO
Replace the
Defrost Timer.
Replace the
Defrost Timer.
Check
the another electric
components.
Replace the
Defrost Timer.
Replace the
Defrost Timer.
Figure  18
CAM SHAFT
DEFROST TIMER
ANOTHER ELECTRIC COMPONENTS
Cooling is impossible
- 12 -
Compressor
doesn't run.
Running state of
Compressor is poor.
Check a starting voltage.
Check if current flows to the
following components.
a. Thermostat
b. Starting devices
c. OLP
d. Compressor coil
e. Defrost Timer
f.  Circuit parts
Low voltage.
Poor contacting and gas leakage.
Shorted or broken.
Poor contacting or shorted.
Coil shorted.
Poor contacting or shorted.
Poor contacting and broken.
Shorted.
Lack of capacity.
Coil of motor Compressor.
Replace
the Compressor.
Replace
each component.
Raise the voltage.
Replace
each component.
Cause
Check if current flows to
starting devices.
Check current flowing in
sub-coil of Compressor.
Check capacity of OLP.
The items described
above are normal.
Cooling ability is poor
Fan motor
doesn't run.
Much frost are
sticked to the cooler.
Poor contacting.
Coil is shorted.
Shorted.
Replace
each component.
Replace
each component.
Replace
each component.
Running is poor.
(Coil is shorted.)
Check current flowing
in door switch.
Check current flowing
in the Fan Motor.
Check the running
condition of Timer.
• Defrost Thermostat
• Fuse-M
• L-cord
• TE-Plate Heater
Check current flowing of
the following components.
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