Refrigerant 414

[porkey 1200]

Can i use R134 in place of R414 and R12 ?

[Tony]

Only if the system already has ester oil in it.

But chances are if it has been running on R12 or R414 it will contain mineral oil. You would then have to flush this out before putting in R134a and the only realistic way these days is by doing repeated oil changes with the old refrigerant used to circulate the new oil. Hopefully this will drag most of the mineral oil back to the compressor. Drain the oil and repeat, typically 3 times.

Then replace 'o' rings, gaskets etc.

Then replace refrigerant with R134a.