I just had my air conditioner replaced last week, and I walked out to check on the tech doing the work just as he finished removing the refrigerant from the old system. By venting it to atmosphere. forehead slap. I was under the impression the EPA will go after technicians personally if they get caught doing that. R410a may not be the same ozone-depleting refrigerant as R-22, but it's still a lot worse than CO2 for greenhouse effect.
I heard they're switching next year away from R410a to something new. But... not propane?
There is a good chance they might have been purging nitrogen they put into the system. If you are replacing the evaporator and condenser but not the line set, it is normal to purge the existing line set with nitrogen to clear anything out.
That is partially what makes it so difficult to catch people doing it, since it is not obvious whether they are venting refrigerant or nitrogen.
Ah, okay, maybe he did capture it after all then. I did notice that it wasn't making any vapor clouds like it seems to when you're unscrewing the lines and a bit escapes. I thought maybe it was just the end of the process and that's why, but nitrogen would totally explain that.
He definitely had a bottle of nitrogen on hand because he used that when pressure testing the new system. And it was just a replacement of the evaporator coil and the condenser, so the line set was reused. Your explanation makes perfect sense, thanks!
Yeah HVAC techs use nitrogen a lot. They use it for pressure testing, cleaning line sets, flowing while brazing to avoid oxidation, and sometimes even to clean out condensate lines. Hopefully your AC is working well, it is in the mid 90s here today in the New England.
I heard they're switching next year away from R410a to something new. But... not propane?