LG LSC27990TT Service Manual page 78

TROUBLE DIAGNOSIS
3-3. Precautions During Heavy Repair
Items Precautions
1. Use of tools. 1) Use special parts and tools for R134a.
2. Recovery of refrigerant. 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
3. Replacement of drier. 1) Be sure to replace drier with R134a only when repairing pipes and injecting refrigerant.
4. Nitrogen blowing 1) Use pressurized nitrogen to prevent oxidation inside the piping.
welding. (Nitrogen pressure : 0.1-0.2 kg/cm2.)
5. Others. 1) Only nitrogen or R134a should be used when cleaning the inside of piping of the sealed
system.
2) Check leakage with an electronic leakage tester.
3) Be sure to use a pipe cutter when cutting pipes.
4) Be careful not the water let intrude into the inside of the cycle.
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