Hi, everybody! I set up a three stage Auto Refrigeration Cascade system to achieve the -180 F box temperature, and the refrigerant was chosen as R404A\R23\R14 mixture, the lubricating oil was synthesize POE. When run this system, I found the evaporate temperature fluctuated in a wide range, after checked the system, it has been found there was a blockage in the gas line by the sticky oil. I think the oil is the big problem. So, does anyone know which type oil should be used in this ARC system? Any input is appreciated!

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