LG LSC27990TT Service Manual page 79

TROUBLE DIAGNOSIS
3-4. Practical Work For Heavy Repair
Items
1. Removal of residual
refrigerant.
2. Nitrogen blowing
welding.
3. Replacement of drier.
Low pressure side
Compressor
Suction
Release
Condenser
Refrigent
Intake
1) Continue to recover the refrigerant for more than 5 minutes after turning the refrigerator off.
2) Install a piercing type valve on the high pressure line (drier side). Then use the appropriate
recovery equipment to recover the refrigerant from the system. When the refrigerant has
been recovered, install a piercing type valve on the low pressure side. IT IS IMPORTANT
TO OPEN THE SYSTEM IN THIS ORDER TO KEEP THE OIL FROM BEING FORCED OUT.
The use of piercing type valves will allow future servicing and eliminates the possibility of a
defective pinch off.
1
Condenser
Refrigent
2
Intake
When replacing a drier:
Weld and parts by blowing nitrogen (0.1~0.2kg/cm
assembling a drier.
When replacing a compressor:
Weld and parts by blowing nitrogen to the low pressure side.
Note) For other parts, nitrogen blowing is not necessary because it does not produce oxidized
scales inside pipe because of its short welding time.
Inserting a capillary tube
Measure distance with a ruler and put a mark (12
mark and weld it.
Precautions
Evaporator
Hot Line
Drier
High pressure side
Evaporator
Hot Line
2 1
Drier
High pressure side
2
+3/-0 ) on the capillary tube. Insert tube to the
- 79 -
KEY POINT
Observe the sequence for
removal of refrigerant.
(If not, compressor oil may
leak.)
KEY POINT
Welding without nitrogen
blowing produces oxidized
scales inside a pipe, which
affect performance and
reliability of a product.
) to high pressure side after
KEY POINT
Be sure to check the
inserted length of capillary
tube when it is inserted.
(If inserted too far, the
capillary tube will be
blocked by the filter.)