Arrived serenity system that is not cooling properly. Upon inspection of the system, system is showing low on refrigerant. Performed a refrigerant leak search. Tested the systems metering orifice. Determined that the system is not leaking any refrigerant and is metering the refrigerant as well as it can. Reached out to install team to charge system to factory spec. Installed UV die in the refrigerant system so if there is a leak, it will be easier to detect. System will be cooling momentarily.