R-22 charge chart on freon box?
Answers: Not sure what you are asking, but you need a license to lawfully purchase R-22 refrigerant these days.
I usually check the element to see how much freon is to be installed. I use the ambient temperature and pressure of the charging gages to give an account if the unit is charged. Also I will use my amp meter to determine if the freon charge is on the money.