Sorry Terry, I can't help you there. I don't convert anything to R-134a. R-134a has 30.4 lbs of pressure @ 35 degrees. R12 has 32.6. This is where the low code is being set. At the condenser R-134a has 229.2 lbs of pressure @ 140 degrees. R-12 has only 205.9. ... Login to read more.