I have been thinking about this refrigerant for quite some time.

R 404A is a blend of 44% R 125/52% R 143a/4% R 134a. Now when there is a leakage in the plant, generally people top it up with R 404A.

Now the question is, that while the gas has leaked out, we are not aware as to which of the above gases and what percentage has leaked, and thus by adding another charge of R 404A we are changing the chemical property of the refrigerant, which will lead to malfunction of the system.

My suggestion is that when there is a leakage of 404A or any other similar mixed blend refrigerant, we should completely evacuate the system and charge a fresh charge of refrigerant. Reusing the refrigerant is not proper as I feel.

Any comments or views on the above shall be apprciated.