Bosch steam boilers generate process heat with output ranges from 175 to 55,000 kilograms per hour and are universally applicable. The sizing and equipment level of the products are designed to individual customer specification with many different options and variants available. The result: maximum energy efficiency, excellent conservation of resources and outstanding availability. The intelligent control technology offered by Bosch ensures convenient, fully-automatic boiler operation. The boiler type ZFR is a shell boiler in three-pass technology with two completely separate flame tubes and smoke gas passages. A reliable steam and heat supply in the high output range. The economizer and superheater can be easily added according to the modular principle. The dimensions of the flame tubes, smoke tube bundles, water chamber and steam chamber have been optimised from the point of view of thermodynamics.