I know that fractionization is not supposed to be an issue with R-410a and that it is supposed to be charged as a liquid. My questions: Does anybody have any experiences where fractionization was discovered, did new refrigerant fix the problem, and what were the symptoms?

I was working on a chiller where we plan some repairs, the biggest being barrel replacement. I wondered if during previous work the chiller had been properly charged. There were three bottles of R-410a on site; they had been there at least three days; two small bottles of virgin refrigerant that each had some liquid remaining, and one 50 pound recovery bottle that was mostly full. I wanted to know if the refrigerant in the bottles was useable. The virgin bottles had exactly correct PT, 56F actual temperature, 56F indicated by low pressure gauge. The recovery bottle, however, had 56F actual temperature and 53F gauge temperature. I labeled the recovery bottle "Do not use, fractionated."

It seems to me that if R-410a were to fractionate, it would most likely lose the high pressure component, and that would show up as lower gauge temperature.