The Hitachi Zaxis 225US-3 is a hydraulic excavator from the third generation of this series, engineered for robust performance and reliability in demanding construction environments. This model features a powerful Hino J05E-T diesel engine with a displacement of 5.12 L, delivering a net power of 114 kW at 2000 rpm. Its hydrostatic transmission ensures efficient power delivery, while its operating weight of 23,000 kg and dimensions, including a length with bucket of 9690 mm and width over tracks of 2990 mm, make it suitable for a wide range of excavation tasks. Notable digging capabilities include a maximum depth of 6610 mm and a reach of 9930 mm, complemented by a bucket capacity of 1.0 m³. This Service Repair Manual provides comprehensive guidance for the Hitachi Zaxis 225US-3 hydraulic excavator. It covers essential maintenance procedures, including fluid capacities for engine oil, coolant, and the hydraulic tank, alongside detailed troubleshooting information and technical specifications. The manual is designed to assist owners, mechanics, and technicians in effectively maintaining and repairing the equipment, ensuring its optimal performance and longevity. All information is presented in English for clarity and ease of use.