R1270 system oil return question

[joanna]

In R717 system,the R717 density is lower than oil,and they are not dissolve.SO we can separate the oil in condenser or receiver.But in R1270 system,I know R1270 density is lower than oil(is it right?).but I don't know if they are dissolve each other like R22,If they are dissolve each other,I think only the evaporator need a oil collector.I use CPI synthetical oil.