IM 1044-2
Centrifugal Chillers
53
that air (and moisture) can penetrate plastic containers. Metal or glass containers with gasket in the top will slow
moisture entry.
In conclusion, a single element of an oil analysis should not be used as the basis to estimate the overall
internal condition of a
Daikin
chiller. The characteristics of the lubricants and refrigerants, and knowledge of
the interaction of wear materials in the chiller must be considered when interpreting a wear metal analysis.
Periodic oil analysis performed by a reputable laboratory and used in conjunction with compressor vibration
analysis and operating log review can be helpful tools in estimating the internal condition of a
Daikin
chiller.
Normal Sample Intervals
Daikin
International recommends that an oil analysis be performed annually. Professional judgment must be
exercised under unusual circumstances, for example, it might be desirable to sample the lubricating oil shortly
after a unit has been placed back into operation after it has been opened for service, as recommended from
previous sample results or after a failure. The presence of residual materials from a failure should be taken into
consideration in subsequent analysis. While the unit is in operation, the sample should be taken from a stream
of refrigerant oil, not in a low spot / quiet area.
Table 17, Upper Limit For Wear Metals And Moisture In Polyolester Lubricants In
Daikin
Centrifugal Chillers
Elements
Upper Limit (ppm)
Action
Aluminum
50
1
Copper
100
1
Iron
100
1
Moisture
150
2 &3
Silica
50
1
Total Acid Number (TAN)
.19
3
Key To Action
1.
Re-sample after 500 hours of unit operation. If content increases less than 10%, change oil and filter and
re-sample at normal interval. If content increases 25% or more, inspect compressor.
2.
Re-sample after 500 hours of unit operation. If content increases less than 10%, change filter drier and re-
sample at normal interval. If content increases 25% or more, monitor for water leak. Since POE lubricants
are hygroscopic, many times the high moisture level is due to inadequate handling and packaging. The
TAN reading
MUST BE USED
in conjunction with moisture readings
3.
For TAN between .10 and .19, re-sample after 1000 hours of unit operation. If TAN increases above .19,
change oil, oil filter and filter drier and re-sample at normal interval.