R-410a fractionization experiences?

[fxb80]

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.

[mark beiser]

The correct term is fractionation.

That recovery bottle could have a little something mixed in it too.

I saw a report a few years ago where someone simulated vapor charging an entire 25# drum of R-410a.
There was less than a 1% difference in the composition of the refrigerant vapor coming out at the start, and the last bit of refrigerant vapor to come out.

For most of us, fractionation of R-410a is just not ever going to be an issue because the difference in the PT relationships of the 2 refrigerants in the blend is very small, but on a system that has a very large quantity of refrigerant, I can see it becoming an issue.

[JBM1000]

Maybe 3 times it has had a 5% effect or more from a hack that kept charging a leaker over and over and over instead of fixing the leaks. It will mainly paranoid your head seeing bubbles in a sight glass if you already have the Sub C & Super H along with all the variables in line. If so, just wait and be patient. I ignore the slightly off in residential till real reasons happen that effect performance bell curves. A mini split may be another story as far as the above statement.