Contains hydrolysis-resistant hardness stabilizers, dispersants and biocidal active compounds preventing corrosion of carbon dioxide and oxygen. Thus, it neutralizes oxygen and carbon dioxide and prevents corrosion and deposit formation. Depending on the hardness of the water and the oxygen concentration of the feed water, the feed water or the condensate line is dosed directly. It prevents corrosion caused by oxygen and carbon dioxide. It prevents the formation of deposits caused by corrosion. It is economical due to its use in low concentration.