When oil has been removed from a compressor, it should be tested for _________________________.

Testing the oil for acidity and contamination is essential after it has been removed from a compressor because these factors significantly impact the performance and longevity of the compressor.

Acidity levels can indicate the presence of harmful substances or degradation products that may have formed due to oxidation or thermal breakdown of the oil. High acidity can lead to corrosion of metal components in the compressor, which can cause premature failure or necessitate costly repairs.

Contamination refers to the presence of foreign particles, water, or other fluids that could interfere with the oil's performance and the compressor's operation. Contaminants can affect lubrication properties, leading to increased wear and tear on moving parts, which ultimately compromises efficiency and operational reliability.

Thus, testing for acidity and contamination allows for proper assessment and maintenance of the oil used in compressors, ensuring they operate smoothly and efficiently.