If the liquid oil acid test kit cannot be used, indicators may be connected to the

• A. Suction line
• B. Discharge line
• C. Liquid line
• D. Oil sump

Answer: (A)

Monitoring oil acidity helps you detect lubricant degradation and moisture-related issues in a refrigeration system. If you can’t use the liquid oil acid test kit, connecting indicators to the suction line is the practical choice because this line carries the oil that is returning to the compressor and is representative of the circulating oil’s condition. The suction line is accessible during service and provides a real-time indication of acidity as the system runs.

The discharge line is hot and filled with high-pressure refrigerant gas, which makes readings unreliable and unsafe. The liquid line mainly contains refrigerant with little oil content, so it wouldn’t reflect the oil’s acidity. The oil sump holds oil but isn’t part of the circulating sample during normal operation and can be harder to access for a representative reading.