A contractor wants to flush our HVAC systems on our subway cars using refrigerant. The system uses R-22. They want to "flush" each car, then reclaim and filter the refrigerant, change all filter driers/strainers and then use the same refrigerant to "flush" the next car. They'll be putting new refrigerant in each car after the flush and filter changeouts.
How can I specify a cleanliness code, if I even can, so I can determine when they can no longer re-use the refrigerant on the next car? I'm concerned about their using "dirty" refrigerant on the next car. Any thoughts would be appreciated as I'm new to this stuff.
Mike
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