Welcome to the first of a two-part series covering the subject of key refrigeration circuit practices. In this post, I will be discussing the importance of properly using nitrogen when brazing refrigerant lines. The process is called “sweeping” and this is not a new process. What has changed over the years is that POE oil has become the predominate refrigerant oil used throughout the world. One characteristic of POE oil is that it’s an excellent detergent and will literally clean the inside of tubing within the refrigerant circuit. This will become problematic when short cuts are taken during installation.