Upon my arrival I spoke with the customer about their concerns with the system not cooling well. Performing my diagnostics I found the outdoor unit is shutting down on a low pressure lock out. I performed an electronic leak search on the indoor system finding that heat transfer media coil has developed a leak. I spoke with the customer about my concerns and went over repair options. They would like these emailed over so they can discuss the repair options they would like to move forward with. I did advise against adding refrigerant to the system due to not knowing how significant the leak may be. I will get part info on the morning from the manufacturer.