I completed annual maintenance on a 2022 Navien combination boiler system. I flushed the domestic hot water side and inspected all components for proper operation. I verified correct combustion operation, inspected and cleaned the condensate trap and drain lines, checked the system pressure, expansion tank, and zone valves, tested safety controls, ignition, and gas valve operation, and inspected venting for any signs of blockage or corrosion. The system was operating efficiently and safely at the time of service.