Your recovery/recycling machine has r-502 refrigerant in it. you now have to recover refrigerant from a unit with r-22. what must be done before the r-22 refrigerant can be recovered/recycled?

Recover as much of the R-502 from the recovery unit as possible, change filter, and evacuate. In addition, to alter the compressor on a system containing R-410A, the person must isolate the compressor then evacuate the isolated section of the system to atmospheric pressure and hold. If system pressure does not increase, then remove the compressor. The recovered refrigerant may encompass acids, moisture and oils and every air conditioning or refrigerating system should be secure by a pressure relief device.