How to Judge Whether Refrigeration Oil Has Deteriorated? Key Indicators You Must Know

Refrigeration oil, also known as lubricant for refrigeration compressors, is the "blood" of a refrigeration system. Just like people whose inner changes will eventually show on the surface, degraded refrigeration oil always leaves detectable signs. Once the oil deteriorates, it will damage the compressor, block pipelines and trigger system failures, bringing huge maintenance costs and downtime losses. Therefore, regular oil condition monitoring is essential for the stable operation of refrigeration equipment.

There are five core indicators to evaluate the deterioration of refrigeration oil:

Visually inspect the oil sample. If the oil turns dark or becomes turbid, it means oxidation and contamination have occurred. In this case, oil replacement is required. Fresh qualified refrigeration oil is usually clear and transparent. Darkening and turbidity are the most intuitive early warning signals.

2. Water Content Test

Water is a major hazard in refrigeration systems. When the water content in refrigeration oil exceeds 100ppm, hydrolysis of POE synthetic oil will be accelerated, producing acidic substances and corroding equipment. It is recommended to replace the oil once this threshold is exceeded.

3. Acid Value Test

Acid value reflects the concentration of acidic by-products generated from oil oxidation or hydrolysis. If the acid value reaches or exceeds 0.5mgKOH/g, corrosive substances will erode compressor metal parts and cause copper plating. Oil replacement is mandatory at this point.

4. Viscosity Measurement

Viscosity determines the lubricating film-forming ability of the oil. If the measured viscosity deviates more than 20% from the original nominal value, the oil cannot be used any longer. Too low viscosity fails to form an effective lubricating film and leads to metal wear; excessively high viscosity increases system resistance and power consumption.

5. Impurity Inspection

Check whether the oil contains solid contaminants, especially metal debris. Metal particles will scratch bearing surfaces, further accelerate oil degradation and may cause compressor seizure. Oil with metal impurities must be replaced immediately.

Simple visual checks can help you make preliminary judgments, but accurate oil condition assessment relies on professional laboratory testing. For reliable refrigeration lubrication solutions and oil analysis services, choose Niubortec.