Friend wants to give me their puron systems 13 sear 2.5 ton AC that they replaced. It was still working fine but 10 years old they wanted to change it out. I currently have a York 2 ton unit that was installed in 1992. It works but I have to add Freon every 6 months or so. Can you change out the sizes without changing the pipes and duct work, etc
You have a refrigerant leak and should probably replace the refrigerant lines regardless. Depending on the type of refrigerant, leaks contribute to ozone depletion and global warming.
A 2.5 ton unit will require a higher airflow rate (typically 350–450 cfm/ton). Your fan motor may or may not be able to be set to a higher speed by moving the jumpers.
With a higher flow rate, your ductwork will induce a higher pressure drop. This means you may not be able to actually achieve the required airflow rate.
A 2.5 ton unit may be oversized and short-cycle more often. This can lead to worse dehumidification performance (your home cools down but stays humid) because moisture condensed into the condensate tray re-evaporates before building up enough to drain.
You would have to consult the installation documentation for the new system. That will specify the size of the lines required. You could also just measure the lines and see if they are the same size as your existing system.
But asking the internet is the wrong way to go. A competent AC installer will give you a free estimate for installing the system.
I would first look at the unit and look for oil staining around the unit and at the indoor coil usually when you see evidence of oil that indicates that there is a leak at that location Schrader valves go bad very easily as well I would replace those those are very common location for freon to leak from