That's odd, everything I have read shows Carrier uses the same 410a as everyone else. They just push the Puron brand of 410a because they helped produce it so they get money from it. Just like Suva 410a or Genetron 410a. I have a Payne (part of Carrier) and my sister has a Carrier system and the pressures are the same as any other brand. The pressure increase came on all units when they switched from 22 to 410.