LG RCWFH Series Instruction Manual page 99

Oil charge
1) Generally the chiller is charged with the oil in the compressor when shipping from the manufacturer, but if not, fol-
low the steps as described below.
2) Charge the oil through the charging valve located at the bottom of the oil tank. At this time, make the inner part of
the machine vacuum using a vacuum pump. (If the refrigerant charging is proceeded, the charged refrigerant will
evaporate and eventually the pressure will rise. Thus, do the oil charging first.) If the inner machine pressure is
high, use the pump from the tank for the charging. In this case, the Discharging pressure of the pump shall be
2
more than 14 kg/cm .G when the suction pressure is 0kg/cm
done at the condition that the chiller is totally stopped.
3) The oil level must be charged more than 2/3 of the sight glass. Also if only the oil pressure and the temperature
are within the designated range, oil foaming may be happening.
4) Be cautious not to let any air enter into during oil charging.
Refrigerant charge
!
CAUTION
When the refrigerant charging or discharging is performed on a machine that uses springs for isolation at the bottom,
fix the springs not to move up and down. The spring moving may stress the connected pipe line.
1) The chiller is charged with nitrogen gas when leaving from the factory. Remove the nitrogen gas at the job-site be-
fore doing the refrigerant charging.
2) Operate the chilled and cooling water pump to prevent freezing when performing the refrigerant charging.
3) It is the most preferable to adjust the refrigerant charge amount when the Chiller is operated under the design
load. Adjust the amount of refrigerant by the difference between chilled water outlet temperature and evaporation
temperature and through the sight glass.
Insulation resistance test
1) Mega test is to apply the direct voltage to the insulation material to obtain insulation resistance by measuring the
leaking current through the material.
For 3000 and 6000V class: use mega for 1000V.
For 380 and 440V class: use mega for 500V.
2) Keep away any unnecessary personnel during the test for it is using high voltage.
3) Cut all the exterior power that is supplied to the chiller before performing the test. The 3-phase motor that is for
above 500hp, can cause danger due to the electric charge when the inspection was performed. Thus, completely
discharge it after the inspection and then handle the ground terminal.
5) Do not perform the high voltage mega test in vacuum condition.
6) Electrical insulation resistance drops in accordance with the temperature increases, and is sensitive to the temper-
ature change which means that it varies. The changed temperature can be written in temperature coefficient and
the temperature coefficient and applied equation is as follows.
Insulation Resistance in
inspecting (°C)
0
5
10
15.6
20
25
30
35
Insulation resistance =
Applied Voltage
Temperature coefficient
0.4
0.5
0.63
0.81
1.00
1.25
1.58
2.00
Table 52. Temperature coefficient under insulation temperature
2
.G. The oil charging or removal, however, must be
Leak Current
Insulation Resistance in
inspecting (°C)
40
45
50
55
60
65
70
75
99
Temperature coefficient
2.50
3.15
3.98
5.00
6.30
7.90
10.00
12.60