CBEX Firetube Boiler

Firetube Boilers

  • Boiler Horsepower: 100 - 2,500 (CBEX-2W), 250 - 800 (CBEX-2D), 250 - 800 (CBEX-3W)
  • Input Capacity (MBH): 4,000 - 102,000
  • Steam or Hot Water: Steam, Hot Water
  • Vessel Design: Firetube
  • Number of Passes: 2 and 3
  • Fuel: Gas, #2 Oil, Combination
  • Emissions (ppm NOx): <5 (CBEX-2W 250-1200), <9 (CBEX-2D 250-800), <9 (CBEX-2W 100-2500), <9 (CBEX-3W 250-800)
  • Steam up to 300 psig
  • Hot water up to 125 psig
  • 100 to 2,500 HP
  • 2 Pass and 3 Pass
  • Natural gas/propane, #2 light oil, combination
  • Waterback or Dryback design
  • Offers 30 ppm NOx with 3% O2 across the 10:1 turndown range
  • Sub 5 ppm NOx without SCR available on most models
  • Meets 10 ppm CO requirement
  • 3 pass model includes an option for an integral pre-piped feedwater economizer 


The Cleaver-Brooks CBEX firetube boiler featuring EX technology is a completely integrated boiler, burner, and controls system. Every core component has been designed and built by Cleaver-Brooks to work together, resulting in the most efficient and lowest-emissions firetube system ever built.


The CBEX achieves higher operating efficiency than competitors' boilers, leading to lower fuel consumption over the life of the boiler. It can also burn renewable fuels and meets the lowest possible emissions of <5 ppm NOx, <10 ppm CO without SCR, helping achieve both emissions reduction and decarbonization goals.

  • Product Overview
  • Related Resources
  • Applications
  • Highest operating efficiency of any scotch marine firetube boiler
  • Exclusive Cleaver-Brooks integral head burner with air-cooled front head
  • Hawk controls for maximum efficiency
  • Single source boiler, burner and control
  • Minimum excess air across the operating range
  • Small footprint
  • 3 pass model includes an option for an integral pre-piped feedwater economizer 


    Using advanced engineering methods, design engineers designed the CBEX to optimize every component of the boiler, including the burner, the furnace, and the tubes, in order to provide optimally balanced heat release zones and minimizing thermal stresses in the boiler. Extended heat transfer tubes only found in EX systems uses Computational Fluid Dynamics (CFD) calculations to optimize the geometry of the tube and increase heat transfer by 85%. The result of the advanced heat transfer design is higher efficiency in a smaller footprint. Offered in a two-pass, waterback or dryback design, the CBEX boiler package is engineered for long life, highest part load (or operational) fuel-to-steam/water efficiency, maximum safety and lowest emissions. Its quiet operation, ease of maintenance and flexibility to add desired options further enhances the package. Integration of the core components is the key to the CBEX systems. The superior Hawk control allows the boiler to run at the absolute maximum efficiency. Reduce fuel use with the optional stack economizer by recovering waste heat from flue gases and using it to preheat boiler feedwater. The LevelMaster low-water cutoff and pump control is the safest control available.

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  • Process Steam
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  • Sterilization
  • Humidification
  • Hospital and Healthcare
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