Essential to prevent slugging and evaporator freeze-ups on startup.
: Evacuate the compressor to at least 5 to 6 mm Hg (Torr) before slowly bleeding refrigerant back into the system to equalise pressures. Troubleshooting Common HSA Issues McQuay HSA Screw Compressor Training | PDF | Valve - Scribd mcquay hsa screw compressor service manual best