Diagnosis of a screw compressor during a technical audit of a refrigeration system at a food industry facility: a case study

Technical audits of refrigeration equipment in food processing facilities enable the identification of hidden faults and help prevent emergency shutdowns that can result in significant operational and financial losses. This review presents a real-world case involving the diagnosis of a screw compressor in a chiller using R404A refrigerant, which exhibited abnormally high discharge temperature while an identical unit in a parallel circuit operated normally. A comprehensive diagnostic approach—including thermal imaging, real-time monitoring of electrical and thermodynamic parameters, vibration analysis, and testing for non-condensable gases—revealed that the root cause was improper configuration of the automatic control system: insufficient compressor off-time, lack of refrigerant pump-down before shutdown, and excessive start cycles per hour. These factors led not only to elevated suction superheat and motor overload but likely also to mechanical wear of the compressor components. The review emphasizes the necessity of an integrated technical audit methodology combining instrumental measurements with a thorough understanding of refrigeration control logic to detect and prevent such operational failures at an early stage.