This double-flame/smoke tube boiler with separate gas passages is suitable for operation with just one burner. The three-pass principle with a rear flue gas reversing chamber positioned in the water chamber was patented in 1952. 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 optimized from the point of view of thermodynamics. Radiant and convection heating surfaces create a unique dynamism when used in single flame tube operation. The heat supplied by the fuel is converted into steam without causing any material stress thanks to flow fittings mounted on the water side.

The main areas of use of ZFR steam boilers are all sectors of business, the processing and supply industries, and public facilities.

Type ZFR ZFR-X
Heat transfer medium High pressure saturated steam High pressure saturated steam
Design Three-pass single-flame tube/smoke tube technology Three-pass single-flame tube/smoke tube technology
Capacity in kg/hour 18 000 up to 55 000 18 000 up to 55 000
Safety design overpressure (in bar) up to 30 up to 30
Max temperature in °C 235 300
Fuel Oil, gas Oil, gas

  • Intuitive boiler control on SPC basis with very high transparency of operating data
  • High level of efficiency due to three-pass technology, an integrated economizer and effective heat insulation materials
  • High level of pressure consistency and steam quality even with widely fluctuating steam demand
  • Automatic start-up, standby and shutdown control SUC
  • Suitable for all burner systems
  • Pollutant reduced combustion thanks to the use of highly developed firing systems and careful matching of the best boiler and burner combination
  • Easy for maintenance – simple to inspect on both the flue gas side as well as the water side
  • Robust, reliable and unsurpassed in its durability
  • Acceptance in accordance with the European Pressure Equipment Directive – applied worldwide
  • Extremely high control range thanks to single-flame tube operation
  • Simple extension options thanks to integrated module technology
  • Simple commissioning due to pre-parameterised boiler control
  • Easy wiring on site thanks to plug-in connections