Persons recovering refrigerant during maintenance service or repair of small appliances must be certified as recovering 80% of the refrigerant whether or not the compressor is operating or achieving a 4 inch vacuum under conditions of ARI 740-1993. It is always a rule than whenever a technician recovers appliances that involves a process of cooling or heating, it is a must that the technician now what type of refrigerant is used. Every refrigerant has specific properties that must be handled differently. It is also important to check a recovery device on a daily basis for any refrigerant leaks.