Good morning to everyone. I work in the refrigeration section of a frozen food distribution company, and have been assigned to assist the team of technicians sent by the factory for the start up of a large Hussmann low temperature R-404 rack refrigeration system, equipped with Copeland Discus compressors. I am trying to get as much informed as possible regarding the correct start-up procedures, and browsing through the factory manual, I just read something that I cannot clearly undestand. One of the first instructions reads as follows: "Isolate. Compressors. Frontseat service valves on suction and discharge. Close oil supply line immediately dowsntream of the Turba-shed." Then the instructions go through the evacuation procedures. When we reach the charging stage, it says: " Charging. Open. Compressors. Backseat service valves on suction and discharge. Open oil supply line immediately downstream of the Turba-shed." From this, I can understand that the compressors are not to be evacuated with the rest of the system, as they remain isolated while the vacuum is taking place. Does this mean that the compressors are to be evacuated independently. I will appreciate any comments. Thank you.