can another refrigerant such as r134a replace r410a refrigerant?
NO !!! There is no replacement for R-410A. Why would you want to replace R-410A with any other refrigerant? R-410A (Carrier calls it Puron) is the new refrigerant used in New HVAC equipment replacing R-22. It is more efficient and ozone friendly. Most of the replacement refrigerants out there will be phased out in a few years because they are blends using other rerigerants such as R-134A and R-22. Some such as R-409A (a replacement for R-12) have Butane in them which is highly explosive and I refuse to use it in systems. I know some stupid people have put R-409A in Automotive A/C's. I wonder what would happen if a leak devlopes and you get a 10,000 volt spark from a damaged spark plug wire.