Why oil is not coming out of compressor during deep vacuum?
The compressor oil has certain density and boiling point. The vacuum levels (down to 200 microns) reached normally is well above the vapour pressure of oil in the compressor. Hence oil will not evaporate. Also the refrigerant In and Outlet of compressor side are well above the oil level- hence there is no chance/possibility of sucking out the oil from compressor.