Servicing Precautions - LG GC-B359B Service Manual

SERVICING PRECAUTIONS

Features of refrigerant (R600a)
• Achromatic and odor less gas.
• Flammable gas and the ignition (explosion) at 494°C.
• Upper/lower explosion limit: 1.8%~8.4%/Vol.
Features of the R600a refrigerator
• Charging of 60% refrigerant compared with a R134a model
• The suction pressure is below 1bar (abs) during the operation.
• Because of its low suction pressure, the external air may flow in the
cycle system when the refrigerant leak, and it causes malfunction in
the compressor.
• The displacement of compressor using R600a must be at least
1.7 times larger than that of R134a.
• Any type of dryer is applicable (XH-5, 7, 9).
• The EVAPORATOR or any other cycle part that has welding joint is
hidden in the foam. (If not hidden inside, the whole electric parts must be
tested with the LEAKAGE TEST according to the IEC Standard.)
• The compressor has label of the refrigerant R600a.
• Only the SVC man must have an access to the system.
Installation place
• Must be well ventilated.
• Must be 20 m 3 or larger.
• Must be no-smoking area.
• No ignitable factors must be present.
Utilities
• Refrigerant cylinder (MAX NET 300g)
• Manometer
• Vacuum pump (600l/min)
• Piercing Clamp
• Quick coupler
• Hoses (5m-1EA, 1m-3EA)
• LOKRING
• Portable Leakage detector (3g/year↓)
• Nitrogen cylinder (for leakage test)
• Concentration gauge
Make sure before Servicing
• Refrigerant
Confirm the refrigerant by checking Name Plate and the label on the
compressor, after opening the COVER ASSY, BACK-M/C.
• If the refrigerant is R600a, you must not weld or apply a heat source.
Air Recharging in Compressor
Before refilling the refrigerant, you must perform the test according to
Chapter 5 (TROUBLESHOOTING CHART). When the defects are
found, you must discharge the residual refrigerant (R600a) in the
outdoor. For discharging the refrigerant R600a, break the narrow
portion of tube extension by hand or with a pipe cutter as shown in
Figure 1. Leave it for 30min in outside to stabilize the pressure with
ambient. Then, check the pressure by piercing the dryer part with
piercing pliers. If the refrigerant is not completely discharged, let the
refrigerator alone for more 30min in outside.
POINT TO BE
BROKEN
SERVICE TUBE
EXTENSION
Figure 1
Attach the service tube installed with a Schrader valve (one-way valve)
by using the LOKRING (Figure 2). Then, connect the Schrader valve
(one-way valve) to the pump that is connected to the discharging hose
leading to the outside. When discharging the residual refrigerant, repeat
3 cycle that includes 3min of the pump running->pump off->30sec of
the compressor running.
CHARGE TUBE
EXTENSION
SCHRADER VALVE
(ONE-WAY VALVE)
LOKRING
Figure 2
After the refrigerant (R600a) is completely discharged, repair any defective
parts and replace the dryer. At any case you must use the LOKRING for
connecting or replacing any part in the cycle (No Fire, No Welding).
Connect the Schrader valve to pump with the coupler. And then turn the
pump on for vacuum state (Figure 3). Let the pump run until the low-
pressure gauge indicates the vacuum (gauge pressure 0, absolute
pressure -1atm or -760mmHg). Recommended vacuum time is 30 min.
Charge the N gas in order to check for leakage from welding points and the
2
LOKRING. If leakages are found, repair the defects and repeat the vacuum
process.
TO THE
VACUUM
PUMP
Figure 3
After the system is completely vacuumed, fill it with the refrigerant R600a up
to what has been specified at your refrigerator Name Plate. The amount of
refrigerant (R600a) must be precisely measured within the error of ±2g by
an electron scale (Figure 4).
If you use the manifold connected with both the refrigerant (R600a)
cylinder and the vacuum pump simultaneously, make sure the
pump valve is closed (Figure 5).
REFRIGERANT
(R600a)
COUPLE
THROTTLE
VALVE
Figure 4
FILLING OR
CHARGE TUBE
TO THE
REFRIGERATION
SYSTEM
TO THE VACUUM PUMP
Connect the charging hose (that is connected to the refrigerant (R600a)
cylinder) to the Schrader valve installed on the service tube. Then, charge
the refrigerant (R600a) by controlling the Throttle valve. When you do so,
do not fully open the Throttle valve because it may make damage to the
compressor. Gradually charge the refrigerant (R600a) by changing open
and close the Throttle Valve (5g at each time). The charging hose must use
a one-way valve to prevent the refrigerant refluence. Close the Schrader
valve cap after the refrigerant (R600a) is completely recharged.
After you completely recharge the refrigerant (R600a), perform the leakage
test by using a portable leakage detector or soapy water.
Test the low pressure (suction) parts in compressor off time and high
pressure parts in compressor on time. If the leakages are found, restart from
the refrigerant (R600a) discharging process and repairs defects of leaks.
After the leakage test, check the temperature of each parts of the cycle.
Check with hands if the CONDENSER and the case (HOT-LINE pipe) that
is contacted to the door gasket are warm. Confirm that frost is uniform
distributed on the surface of the EVAPORATOR.
- - 2-
PRESSURE
GAUGE
CHARGING HOSE
WEIGH SCALE
VALVE TO BE OPENED
WHEN REFILLING
TO THE CHARGE
CYLINDER
VALVE TO BE CLOSED
AFTER VACUUM
Figure 5