In this paper, an extensive experimental work has been carried out on phase-equilibrium measurements in binary systems constituted by refrigerants CF3−CHF2 (R125), CF3−CH2F (R134a), CF3−CH3 (R143a), and CH2F2 (R32) and a commercial perfluoropolyether Fomblin YLOX100 and Fluorolink D10H, used as lubricant oils. The measurements are related both to vapor−liquid and liquid−liquid equilibria, and the collected experimental data have been interpreted with the extended Flory−Huggins model. This model allows, simultaneously, good performances in the description of both the vapor−liquid isotherms and liquid−liquid miscibility gaps with the same set of adjustable parameters.