S R C C Alternatives to H F s in the efrigeration and Air Conditioning Sector ection 01 39 1.6.2 how to replace the oil during retrofits Su mmary Oil change methods The change of the oil is the major obstacle to retrofit an HCFC system to the “standard” HFC refrigerants used in new plants, since it is not easy to get the old oil out of the system. The oil in a refrigeration system is distributed over the whole system even if a majority will typically be in the compressor. Most small systems have no ports designed to drain the oil out of the compressor. On larger systems, ports or valves are common, however only 40 to 80% of the oil can be drained through these.