LG LSC27990TT - Cooling Cycle Heavy Repair

3. Cooling Cycle Heavy Repair
3-1. The Heavy Repair Standards for Refrigerator with R134a Refrigerant
TROUBLE DIAGNOSIS
- 76 -
NO. Items Unit Standards Purposes Remarks
1 Pipe and piping Min. Pipe: within 1 hour. To protect The opening time should be reduced to a
system opening time. Comp: within Moisture half of the standards during rain and
10 minutes. Penetration. rainy seasons (the penetration of water
Drier: within into the pipe is dangerous).
20 minutes.
2 Welding. Nitrogen Weld under To protect - Refet to repair note in each part.
Pressure. Nitrogen oxide scale - R134a refrigerant is more susceptible to
atmosphere formation. leaks than R12 and requires more care
(N
2 pressure: during welding.
0.1~0.2 kg/cm
2
) - Do not apply force to pipes before and
after welding to protect pipe from
cracking.
3N
2 sealed parts. Confirm N2 Confirm air leaking To protect - In case of evaporator parts, if it doesn't
leak. sounds when moisture make noise when removing bushing
removing bushing penetration. cap blow dry air or N
2 gas for more than
cap. 1 min use the parts.
Sound: usable
No sound:
not usable
4
Refrigeration Evacuation Min. More than To remove
Cycle. time 40 minutes. moisture.
Vacuum Torr Below 0.03(ref) Note: Only applicable to the model
degree equipped with reverse flow protect
plate.
Vacuum EA High and low Vaccum efficiency can be improved by
Pressure sides are operating compressor during evacuation.
evacuated at the
same time for
models above 200 L
Vacuum EA Use R134a To protect The bushing pipes for R12 refrigerant will
piping exclusive mixing of be melted when they are used for R134a
manifold. mineral and refrigerant causes of leak.
ester oils.
Pipe EA Use R134a To protect
coupler cxclusive. R12 Refri-
gerant mixing.
Outlet R134a exclusive.
(Socket)
Plug R134a exclusive
5 Refrigerant weighing. EA Use R134a Do not mix - Do not weigh the refrigerant at too hot or
exclusively. with R12 too cold an area. (25°C [77°F] is adequate.)
Weighing refrigerant. - Use copper charging canister
allowance: ±5g Socket:2SV Plug: 2PV R134a
Note: Winter: -5g Note : Do not burn O-ring (rubber) during
Summer: +5g welding.
6 Drier replacement.
- Use R134a exclusively To remove
for R134a refrigerator the moisture
-
Replace drier whenever from pipe.
repairing refrigerator
cycle piping.
7 Leak check. -Do not use soapy Detect - Check oil leak at refrigerant leak area.
water for check. refrigerant Use electronic leak detector if oil leak is
It may be sucked leak area. not found.
into the pipe. - The electronic leak detector is very
sensitive to halogen gas in the air. It also
can detect R141b in urethane. Please
practice, therefore, many times before use.