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

I believe what they are proposing is fine as long as they are using a reclaiming machine from Robinaire or some other refrigerant company to remove the high boilers (oil, water, dirt) from the refrigerant prior to flushing the next system. The reclaiming machines were designed for extracting, cleaning and returning used refrigerant to refrigeration systems under repair. I believe there is a American Refrigeration Institute standard for recycling machines ARI 740 which dictates the cleaniless of the recycled refrigerant. The only used refrigerant that can't be reused is refrigerant from a R22 system that has suffered a motor burnout - produces HCl/HF acids, other corrosive/unstable compounds, other volatile compounds such as methane, etc. that would contaminate the "flushed "system

Thanks for the reply. The contractor stated they were looking into using a reclaim system from Van Steenburgh which meets ARI 700 Standards for resale. The brochure says it separates oil, acid, water and hard particle contaminants. Looks like it should be okay.