It is critically important to adequately dehydrate and degas the cooling system prior to the introduction of refrigerant.  By dehydrate, we mean remove as much moisture as possible and by degas remove as much air and other gases as possible.  Moisture and gases present within the system have a chemical reaction within the system causing the oil within the system to break down.  This results in a chemical decomposition of the refrigerant which combined with moisture in the cooling unit forms an acidic condition.  Read more...