I performed a leak search through the entire mini split system and was unable to locate a leak with either the electronic leak detector and in combination with the leak detector and nitrogen. When pressurized in the system with nitrogen, the system held pressure for 20 minutes. I then placed the system on a vacuum and was able to reach down to 480 µm which if there was a leak the system would not get below 1000 µm. however the system was completely empty of refrigerant. Very puzzling situation. I suspect that if in fact, there is a leak, it’s a very tiny and minuscule leak. I advise the customer that we would monitor the system after recharging the entire system throughout the next maintenance and see if the system suffer any decrease in Refrigerant levels. I recharge the system back up with 6.17 pounds of refrigerant as specified by the data plate. Customer is going to need to have a nitrogen leak search performed as the system has a leak showing error. Code 35. Will need to resche