Do refrigerant fluid mixtures break down if there is a leak?


YES AND NO

Azeotrope mixtures do not break down, and behave like pure substances.

As for zeotrope mixtures, they do not always break down if there is a leak, for two reasons:

 

1 - The mixtures are made up of fluids of similar natures and as they have very small temperature variation they break down only slightly. In the case of a leak in gaseous state, simple refilling it reestablishes the mixture. Eg: R-404A, R-410A.

2 - A mixture with a high variation (for example R-407C) does not break down in a gaseous state in the presence of its liquid, or when it stops. In operation, the probability of a mixture breaking down is virtually nil.

To remove doubt, simply measure the pressure/temperature ratio and this will show if the mixture has changed from its initial proportions. Acceptable pressure is P< 0.3 to 0.5b max.