How to charge Refrigerant R404?

1. VACUME your unit(freezer,visi top,plate freezer or e.t.c) well.
2. GET a digital weight scale
   
3. SET your r404 tank on tray wight scale and press tray button.
4. CHARGE r404 by weight you must have knowledge how much refrigerant you need to charge in your unit.
5. TIGHT your r404 tank nab 
6. SET your unit to switch on.