How can oil be identified in a compressor with unknown refrigerant?
Without tests to be done in a laboratory this is difficult. Hence for a technician first find out what has was/is in the system. This issue is covered earlier on. If it is observed to be HFC refrigerant for sure the oil in the compressor must be POE oil, else if it is CFC then the oil should be mineral oil. Apart from the above if it is HC Blend then the oil could be either POE or mineral oil, but most likely the later. Q18 Importance of vacuum in microns Micron is the smallest unit for pressure measurement. For example 1 mm of Hg is equal to 1000 microns (1000 times smaller) , while evacuating the domestic refrigeration system pressure may come down to around 500 microns Hg. Hence for accurate measurement it is necessary to measure the pressure (vacuum) in microns.
