How many pounds of freon does a central air conditioner hold?

It is not possible to give a precise answer, since central air conditioning systems use condenser and evaporator units separated by variable lengths of tubing, depending on the particulars of an installation.

Most units hold 4 to 6 lb of refrigerant, depending on the cooling capacity (2 ton to 4 ton). Check the data plate on condensor it will tell you the exact ounces it holds then do the math.

Contact the manufacturer of the A/C Unit. Then you must adjust the charge up from what the nameplate says to compensate for the piping between the two components of the unit.