Find leak in system where refrigerant is escaping. This includes tear down of unit to access evaporator coil in attic. UV light to search for fluorescent dye in system to trace leak. And adding 1lb of refrigerant to keep system cooling properly. Added refrigerant to system until Sub Cooling levels are correct for unit and coil. Looked inside of coil in attic attached to furnace and did not find a leak and no fluorescent dye. Checked condenser coils and near compressor and found no leaks. Will need to return again when system loses refrigerant and try to find leak at later time. Customer will call if system is not cooling again.