infact the AC hose Fitting R1234yf Freon gas is new, it can be replaced by R134a and there will be no damage to the compressor but doing so is illegal. why?Because the expansion valve setting for R-1234yf refrigerant is different compared to R-134a. Changing from R-1234yf to R-134a refrigerant may result in a system with incorrect refrigerant flow and heat exchanger mal-distribution which may cause a loss of cooling performance or durability concerns.
The TXV setting is also different when an Internal Heat Exchanger (IHX) is used, which is common in R-1234yf MAC systems. This may mean that suction line pressure drop is increased, which might affect the setting for a pressure controlled compressor, resulting in poor cooling or evaporator core freezing.
This can be particularly damaging in the case of dual evaporator systems where the balance of front and rear expansion devices helps to avoid oil trapping in the rear evaporator.AC hose Fitting R1234yf was created as a more environmentally friendly replacement to R134a