I'm hoping someone in this group will take the time to answer this for me.
I'm in the middle of a course on HVAC in high-rises. The instructor has stated that the oil in the HVAC system should be checked regularly for quality and impurities. She says that if refrigerant is detected in the oil then there is a problem. I was always thought that there is oil in the system with the refrigerant and that this oil lubricated the compressor etc.and one would expect to find refrigerant mixed in with it. I thought that this was why you are always told to let a newly delivered fridge stand for an hour or two before turning it on, to let the oil drain back down into the compressor.
What gives?
tia
Peter H