Daikin WCT Series Operating & Maintenance Manual page 66

Table 22, Metal and Moisture Limits in Polyolester Lubricants
Aluminum
Copper
Iron
Moisture
Silica
Total Acid Number (TAN)
Key to Action
1) Re-sample after 500 hours of unit operation.
2) Re-sample after 500 hours of unit operation.
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) If TAN is less than 0.10, system is safe as far as acid is concerned.
In general Daikin International does not recommend changing oil and filters on a periodic basis. The
need should be based on a careful consideration of oil analysis, vibration analysis and knowledge of
the operating history of the equipment. A single oil sample is not sufficient to estimate the condition
of the chiller. Oil analysis is only useful if employed to establish wear trends over time. Changing oil
and the filter prior to when its needed will reduce the effectiveness of oil analysis as a tool in
determining machinery condition.
The following metallic elements or contaminates and their possible sources will typically be
identified in an oil wear analysis.
Aluminum
Typical sources of aluminum are impellers, seals or casting material. An increase in aluminum
content in the lubricant may be an indication of impeller or other wear. A corresponding increase in
other wear metals may also accompany an increase in aluminum content.
Copper
The source of copper can be the evaporator or condenser tubes, copper tubing used in the lubrication
system such as oil cooler lines, scroll or motor drain lines or motor cooling systems or residual
copper from the manufacturing process. The presence of copper may be accompanied by a high
TAN (total acid number) and high moisture content. Lubricants containing an anti-wear formulation
might react with copper and result in high copper content in the oil.
OMM WCT
ELEMENT UPPER LIMIT (PPM)
a) If content increases less than 10%, change lubricant and lubricant filter and re-
sample at normal interval (usually annual).
b) If content increases between 11% and 24%, change lubricant and lubricant filter and
re-sample after an additional 500 hours of operation.
c) If content increases more than 25%, inspect compressor for cause.
a) If content increases less than 10%, change filter-drier and re-sample at normal
interval (usually annual).
b) If content increases between 11% and 24%, change filter-drier and re-sample after an
additional 500 hours of operation.
c) If content increases more than 25%, monitor for a water leak.
a) For TAN between 0.10 and 0.19, re-sample after 1000 hours of operation.
b) For TAN above 0.19, change lubricant, lubricant filter, and filter-drier and resample
at normal interval
Centrifugal Chillers
ACTION
50
100
100
150
50
0.19
1
1
1
2 & 3
1
3
D-EOMWC01302-16EN - 66/84