Nitrogen Purge While Brazing

Welcome to Enertech University, online training by Enertech. One of the most overlooked steps is the use of a nitrogen purge while brazing. Without the use of nitrogen (or helium), black oxide forms (cupric oxide). After cooling the oxide forms scale and flakes off over time. We see this on copper tubing as a light to dark brown discoloration. As refrigerant (especially R-410) flows through the tubing, it scrubs the tubing and flakes break loose. In time, metering devices, reversing valves, compressors and other devices will clog and fail. Thanks for watching!