Service and maintenance of steam turbines control systems operated includes a set of activities aimed at maintaining their operational or fault-free condition which is provided in the design, factory, operational or regulatory documents, and the need for which is revealed thanks to operation experience. Equipment maintenance operations can be performed on the stopped equipment according to the annual repair schedule. Maintenance includes equipment condition checks, tests according to the normative and technical documentation, inspection and set-up. This allows us to identify operation defects and violations of safety rules as well as to specify the scope of obligatory or recommended works for the next repair.