Service
46 Chiller Air-cooled Screw
The bearings used in the compressor required a small but steady quantity of oil for lubrication; the oil injection
into the compression chamber creates an oil sealing film in the compression housing for increasing the efficien-
cy and absorbing a part of heat of compression. In order to separate the oil from the mixed refrigerant gas, an
oil separator is required to ensure the least amount of oil carried into the system. Pay more attention to the oil
temperature, which has a very significant factor to the compressor bearings’ life. High oil temperature will
reduce the oil viscosity and cause the poor lubrication and heat absorption in the compressor as well. The oil
viscosity is recommended to keep over 10mm
2
/ s at any temperature. The oil temperature just keeps above
system condensing temperature to avoid the refrigerant migration into system in the summer. There is high oil
viscosity in the low ambient temperature circumstance, it could cause compressor in heavy duty to be started
up resulting less oil pressure in oil line to load the compressor. The better solution is to have higher condensing
temperature in a short time by warming up the oil.
The compressor is equipped two oil sight glasses as a standard, one is the oil high level sight glass, and the
other is the oil low level sight glass. The normal oil level in the compressor oil tank should be maintained above
the top of the low oil sight glass and in the middle level of high oil sight glass when compressor is running.
Applicable oil types are shown in the below.
UNITS
COLOR, ASTM
SPECIFIC GRAVITY
VISCOSITY
FLASH POINT
POUR POINT
T.A.N
COPPER STRIP 100°C/3hr
MOISTURE
FLOC POINT
DIELETRIC STRENGTH2.5mm
-
-
104°F
212°F
°F
°F
mg KOH/g
-
ppm
°F
KV
MOBIL EAL
ICI EMKARATE
CPI SOLEST
68
120
220
370
68
100
RL411
RL375
RL421
-
-
-
-
0.5
0.5
1.5
L2.0
L1.0
0.945
0.94
0.95
0.955
0.971
0.966
0.9723
0.9783
0.9759
64
131
215.9
385.96
62.5
95.8
48
74.1
134
8.9
14.53
20.8
29.23
8.3
10.5
7.3
10.1
15
510.8
489.2
519.8
575.6
489.2
500
523.4
474.8
509
-45.4
-33.7
-13
-5.8
-45.4
-34.6
-40
-31
-34.6
-
-
-
-
-
<0.05
<0.05
<0.05
-
-
-
-
-
-
-
-
-
-
-
-
-
<100
<100
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Fig. 24
Table 15