Failure analysis of condensing units for refrigerators with refrigerant R134a, R404A

The article deals with analysis of defects of condensing units for refrigerators with R134a, R404A refrigerant, which caused frequent complaints to the company. Up to 30% of the claims related to a valve of the condensing unit. Various quality management tools and risk assessment methods were used to solve the problem. The Pareto analysis and Lorenz curve were used to determine the significant minor causes that need to be addressed to resolve the majority of problems. Based on the Fault Tree Analysis (FTA), a change in the technological process was made for assembly and installation procedure of the valve to the base plate and in hard brazing of the tube and the valve, thus reducing the number of defects in the condensing unit by 40%. Valve defects have been reduced by nearly 50%. (C) 2018 Elsevier Ltd and IIR. All rights reserved.