Compressor Oil Contamination - Part I

Refrigerant oils, critical to the lubrication of the compressor, must be kept free of contamination and breakdown. Contamination can be due to foreign particles, moisture or oxygen. Breakdown can be due to excessive temperature or chemical reactions.

Poor mechanical maintenance can lead to contamination due to foreign particles or chemical breakdown. Poor handling practices can result in the lubricant being contaminated by foreign particles or moisture. Refrigerant leaks or improper system settings can result in contamination due to moisture or oxygen and lead to chemical breakdown. Chemical breakdown can result in decreased lubrication, sludges, and the formation of acids.

Foreign Particles
• Introduced during handling due to poor handling practices.
• Generated during operation due to poor maintenance practices resulting in excessive wear.
• Sludges created by chemical breakdown.
• Copper plating due to reactions between refrigerant piping and acid contamination.

Chemical Breakdown
• Moisture due to poor handling practices or refrigeration leaks.
• Acids formed due to refrigeration leaks.
• Excessive temperature due to reduced clearance, poor oil quality, and improper operating setpoints.

Contamination for any reason results in reduced clearances and restrictions in oil channels which lead to excessive friction and higher temperatures. The resulting breakdown of the oil, and restricted oil delivery, results in even higher temperatures and ever accelerating breakdown. The result is increased wear and unplanned downtime.

In Part II we will discuss how to avoid, identify, and mitigate these problems.