Johnson Controls YORK YK Operation Manual page 10

Total acid number (ASTM D974)
The total acid number (TAN) is the amount of potassium hydroxide in milligrams (mg) that is
required to neutralize the acid in one gram of oil. The TAN signifies the basic condition of the fluid
by giving a value that signifies the amount of acidic breakdown that the fluid has undergone. TAN is
a useful indicator for risk of internal corrosion to copper plating.
Particle count
Particle count analysis shows how many metallic and non-metallic particles are present and at what
sizes. The particle count analysis includes the following tests:
• Identifying solid material
• Identifying abnormal wear conditions
• Monitoring the effectiveness of filtration
• Measuring overall system cleanliness
Metal analysis (ASTM D874)
Metals analysis, by mass spectrometer or by sulfated ash procedure, tests for wear and additive
metals. It instrument detects dissolved metals and particles smaller than 5 microns, assuming they
are suspended in the lubricant.
Moisture by the Karl Fischer method
Using the Karl Fischer you can identify of moisture or freestanding water is in the oil. Excess
moisture leads to increased TAN levels and formation of acids. Moisture content is reported in parts
per million (ppm).
10 YORK Oil Application, Oil Change Interval, and Oil Quality Limits Replacement Recommendations
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