Afternoon all

R134a molecule size, Iv been told that the molecular size of R134a is smaller than OFN
is this correct?
Recently leak/pressure checked a freezer on R134 (205grams)
System was under pressure test for a week with trace gas(5%hydrogen,95% N2)
With no loss of pressure and no leak picked up with a carbon sniffer.
On re-gassing with R134a and rechecking with a refrigerate sniffer it again picked up small traces of refrigerate on the evap coil put system into hot gas defrost and the sniffer screams it’s head off.