Experimental investigations of boiling in flow of a refrigeration medium under disturbances typically occurring in refrigeration units are conducted. The development and decay of boiling is stimulated by periodic changes of mass flux density in the coil tube. It is confirmed that the two-phase systems exhibit wave properties and the disturbances generated in the system propagate with finite velocities. An experiment-based correlation to describe the disturbance propagation velocity during the development and decay of boiling in the coil tube is elaborated. The investigations are carried out for an environment-friendly refrigerant R404A supplied under pressure to the heat exchanger.