A refrigerant mixture whose components boil at different temperatures, so it has glide and can fractionate.
Zeotropic blends are mixtures of two or more refrigerants that do not behave as one substance. Because each component has its own boiling behaviour, the blend shows temperature glide and can separate (fractionate) if vapour is drawn from a cylinder or leaks from the vapour space. Refrigerants in the R-400 series are zeotropic blends.
Two practical consequences: charge them as liquid so the composition stays correct, and treat a large vapour leak as a possible change in composition.
Exam work areas
B · Tools, piping and refrigerant handling