I performed a geothermal clean and tune. During the cleaning I found the geo was locked out on low refrigerant pressure. I checked the pressure in the system. It was empty. I filled the unit with nitrogen to find a leak. Found a brazed joint was leaking. I rebrazed the joint. Pressure tested system. It held pressure. Pulled unit in a vacuum. Added the factory charge of refrigerant. Cycled the unit and tested the performance. During the clean and tune I wiped out and dusted the unit. Tested electrical components and checked wiring. Cleaned drain pan and drain Line. Checked flow center, the water level is good. Checked the temperature rise it was at 26. The unit is producing 32010 btus of heat which is good. The repair is covered under parts and labor warranty. The geo unit is operating.