existing refrigerant

What Is Mo99 Refrigerant? Can R-22 be topped off with FreonTM MO99? No. FreonTM MO99 should not be used to top off R-22 systems. Mixing refrigerants is not recommended. Can you top off R-22 with MO99? Can R-22 be topped off with FreonTM MO99? No. FreonTM MO99 should not be used to top off R-22