Upon arrival discussed with homeowner concerns of unit not cooling. Situation started in the middle of the night. After further inspection, it was found that the unit was completely void of refrigerant. Homeowner approved leak search. Inserted, high-pressure nitrogen and immediately found leak inside condensing unit due to being audibly noticeable. Found temperature sensor on liquid line loose and chafing copper causing several imperfections and one leak. Performed leak repair via silver flowing by brazing method. Removed existing filter, dryer at air handler and replaced with new bi-flow dryer. Performed system vacuum down to 500 µm and recharge system with 14.67 pounds of R410a. Performed performance and safety test and dialed in subcooling by approach. All systems functioning normally at this time and to manufacture specifications.