I don't get why you say about "diff machines" between R12 and R134... the only diff is the niple port and there are adapters for that.
At least locally, any A/C shop is able to work on any refrigerant without diff machines really
things work different up here.
It is illegal to vent freon to the atmosphere. It must be recovered and recycled. If you cross contaminate your R12 with R134, or vice versa, then you have an expensive waste product to dispose of.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
