Chapter 7 Trouble Diagnosis; Cooling Cycle Heavy Repair - LG LSSB2691ST Service Manual

TROUBLE DIAGNOSIS

1. Cooling Cycle Heavy Repair

1-1. The Heavy Repair Standards for Refrigerator with R134a Refrigerant
NO. Items
1 Pipe and piping system
opening time.
2 Welding.
3 N sealed parts.
2
4 Refrigeration Evacuation
Cycle. time
Vacuum
degree
Vacuum
Vacuum
piping
Pipe
coupler
Outlet
(Socket)
Plug
5 Refrigerant weighing.
6 Drier replacement.
7 Leak check.
Unit Standards
Min. Pipe:within 1 hour.
Comp: within
10 minutes.
Drier: within
20 minutes.
Nitrogen Weld under Nitrogen
Pressure. atmosphere
(N pressure: 0.1~0.2
2
kg/cm 2 )
Confirm N Confirm air leaking
2
sounds when removing
leak.
rubber cap.
Sound:usable
No sound:not usable
Min.
More than 40 minutes.
Torr Below 0.03 (ref)
EA High and low Pressure
sides are evacuated at
the same time for
models above 200
EA Use R134a exclusive
manifold.
EA Use R134a cxclusive.
R134a exclusive.
R134a exclusive.
EA Use R134a exclusively.
Weighing
allowance: ±5g
Note: Winter: -5g
Summer: +5g
- Use R134a exclusively
for R134a refrigerator
- Use R12 exclusively for
R12 refrigerator
- Replace drier
whenever repairing
refrigerator cycle
piping.
- Do not use soapy
water for check.
It may be sucked into
the pipe.
Purposes
To protect The opening time should be reduced to
a half of the standards during rain and
Moisture
rainy seasons (the penetration of water
Penetration.
into the pipe is dangerous).
To protect - Refet to repair note in each part.
oxide scale - R134a refrigerant is more susceptible
formation. 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.
To protect - In case of evaporator parts, if it
moisture doesn't noise when removing rubber
penetration. cap blow dry air or N
than 1 min use the parts.
To remove
moisture.
Note: Only applicable to the model equipped
Vaccum efficiency can be improved by
operating compressor during evacuation.
To protect The bushing pipes for R12 refrigerant will
mixing of be melted when they are used for R134a
mineral and refrigerant causes of leak.
ester oils.
To protect
R12
Refrigerant
mixing.
- Do not weigh the refrigerant at too hot
Do not mix
or too cold an area. (25°C [77°F] is
with R12
adequate.)
refrigerant.
- Use copper charging canister
Socket:2SV Plug: 2PV R134a
Note : Do not burn O-ring (rubber)
To remove
the moisture
from pipe.
Detect
- Check oil leak at refrigerant leak area.
Use electronic leak detector if oil leak is not
refrigerant
found.
leak area.
- 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.
22
Remarks
gas for more
2
with reverse flow protect plate.
during welding.