The refurbishing of the oxygen concentrator Bitmos OXY 6000 motherboard. This concentrator came to us with ERROR and did not work correctly. We found corroded components and we were able to fix this issue. Unit started to work, but gave another error of oxygene flow. Actually it works up to 4.5 liters per minute, but starts giving an error on the flow of 5-6 liters. This is the problem on zeolite condition in generator. Unit needs of replacement of zeolite rock.