Servicing Precautions - LG GR-M652Y*A Service Manual

SERVICING PRECAUTIONS

Air Recharging in Compressor
Test the refrigeration by connecting it electrically before
refilling operation. It is necessary to ascertain the function
of the motor-compressor and identify the defects
immediately. If the defects have been found, empty the old
system of eventual 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 extension completely with male Hansen and
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 heating
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)
TO THE
VACUUM PUMP
PRESSURE
GAUGE
Air evacuating from the system begins so 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 60 minutes.
(Figure 3)
In case that a considerable leakage occurs and to stop the
vacuum pump will be necessary and 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 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
CHARGE TUBE
EXTENSION
FEMALE
HANSEN
MALE HANSEN
SOLDERING POINT
Figure 2
Figure 3
- 3 -
is over, add the quantity in grams of R-134a to the
refrigerant system. Remember that every system has an
exact quantity of R-134a with a tolerance of
can be added. (Figure 4)
TO THE R-134a CYLINDER
Before performing this operation (if the vacuum pump and
refilling cylinder are connected), make sure that the valve
placed between the vacuum pump and refilling tube are
closed to keep the Freon for adding to the system. (Figure 5)
FILLING OR
CHARGE TUBE
TO THE REFRIGERATION
SYSTEM
TO THE VACUUM 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 Freon in the cylinder and must add 165 grams
to the group, this amount will be reached when R-134a has
dropped to 585 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 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 making the pressure go down 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 0.10 to 0.4
atmosphere.
5 grams that
TO THE REFRIGERATION
SYSTEM
Figure 4
VALVE TO BE OPENED
WHEN REFILLING
TO THE CHARGE
CYLINDER
VALVE TO BE CLOSED
AFTER VACUUM
Figure 5