LG / GOLDSTAR GR-392CSC
Service Manual

SERVICING PRECAUTIONS
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-12(R134a) 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 CHARGE TUBE EXTENSION FEMALE HANSEN

vacuum operation is over, add the quantity in grams of R-12(R134a) to the refrigeration system. Remember that every system has an exact quantity of R-12(R134a) with a tolerance of ±5 grams that can be added. (Figure 4)

TO THE R-12(R134a) CYLINDER

MALE HANSEN

TO THE REFRIGERATION SYSTEM

Figure 4
SERVICE TUBE EXTENSION SOLDERING POINT

Figure 1

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)

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)
FILLING OR CHARGE TUBE VALVE TO BE OPENED WHEN REFILLING

TO THE REFRIGERATION SYSTEM

TO THE CHARGE CYLINDER

VALVE TO BE CLOSED AFTER VACUUM TO THE VACUUM PUMP PRESSURE GAUGE TO THE VACUUM PUMP

Figure 5

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

In addition, check the graduated scale on the cylinder for the quantity of R-12(R134a) 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-12(R134a) 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-12(R134a) 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 motorcompressor. 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-12(R134a) 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.