LG LSC27990TT Service Manual page 79

TROUBLE DIAGNOSIS
3-4. Practical Work For Heavy Repair
Items Precautions
1. Removal of residual
refrigerant.
2. Nitrogen blowing
welding.
3. Replacement of drier.
Evaporator
Low pressure side
_ KEY POINT
tL Observe the sequence for
removal of refrigerant.
(If not, compressor oil may
Refrigen_.__.._Helease Condenser ide leak.)
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.
Evaporator
j ,o,,Jne
_ _ _ \ Drier /
_ I High pressure side
R 2_ Condenser
Intake
KEY POINT
Welding without nitrogen
blowing produces oxidized
scales inside a pipe, which
affect performance and
reliability of a product.
When replacing a drier:
Weld (_) and (_) parts by blowing nitrogen (0.1-0.2kg/cm2) to high pressure side after
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.
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.)
Inserting a capillary tube
Measure distance with a ruler and put a mark (12+3j-0)on the capillary tube. Insert tube to the
mark and weld it.
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