Performed AC diagnostic on one-year-old carrier condensing unit. Upon my diagnostic I found that the system was completely flat on R410a refrigerant. 5 ton carrier- 1. Put refrigerant gages on to find that system was completely flat and contained no refrigerant at all. 2. Somewhere within the refrigeration cycle there is a huge leak. 3. Leak can be present somewhere within condenser location, line sets within wall, and evaporator coil. Recommendations- 1. Repair refrigerant leak location, Pressurize system with nitrogen, pull tight vacuum, Break vacuum with 15 pounds of refrigerant.