Cooling Cycle Heavy Repair - LG LSC27990TT Service Manual

TROUBLE DIAGNOSIS
3. Cooling Cycle Heavy Repair
3-1. The Heavy Repair Standards for Refrigerator with R134a Refrigerant
NO. Items Unit Purposes Remarks
1 Pipe and piping Min. To protect The opening time should be reduced to a
system opening time. Moisture half of the standards during rain and
Penetration. rainy seasons (the penetration of water
into the pipe is dangerous).
2 Welding. Nitrogen
Pressure.
3 N2 sealed parts.
Refrigeration
Cycle.
Evacuation
time
Confirm N2
leak.
Outlet
(Socket)
Plug
Refrigerant weighing.
Min.
Standards
Pipe: within 1 hour.
Comp: within
10 minutes.
Drier: within
20 minutes.
Weld under
Nitrogen
atmosphere
(N2 pressure:
O.1-0.2 kg/cm2)
Confirm air leaking
sounds when
removing bushing
cap.
Sound: usable
No sound: not usable
More than
40 minutes.
To protect
oxide scale
formation.
To protect
moisture
penetration.
To remove
moisture.
- Refet to repair note in each part.
- R134a refrigerant is more susceptible to
leaks than R12 and requires more care
during welding.
- Do not apply force to pipes before and
after welding to protect pipe from
cracking.
- In case of evaporator parts, if it doesn't
make noise when removing bushing
cap blow dry air or N2 gas for more than
1 rain use the parts.
6 Drier replacement.
Leak check.
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 200j_
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-
jerant mixing
R134a exclusive.
R134a exclusive
EA Use R134a
exclusively.
Weighing
allowance: +5g
Note: Winter: -5g
Summer: +5g
-Use R134aexclusively
forR134arefrigerator
-Replace drierwhenever
repairing refrigerator
cycle piping.
-Do not use soapy
water for check.
It may be sucked
into the pipe.
Do not mix
with R12
refrigerant.
To remove
the moisture
from pipe.
Detect
refrigerant
leak area.
- Do not weigh the refrigerant at too hot or
too cold an area. (25°C [77°F] is adequate.)
- Use copper charging canister
Socket:2SV Plug: 2PV R134a
Note : Do not burn O-ring (rubber) during
welding.
- Check oil leak at refrigerant leak area.
Use electronic leak detector if oil leak is
not found.
- The electronic leak detector is very
sensitive to halogen gas in the air. It also
can detect R141 b in urethane. Please
practice, therefore, many times before use.
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