Condensing Hydronic Boilers

  • Input Capacity (MBH): 500 - 6,000
  • Steam or Hot Water: Hot Water
  • Vessel Design: Firetube
  • Number of Passes: 1
  • Design Temperature (deg F): 210
  • Fuel: Natural Gas, Propane, Combination firing
  • Emissions (ppm NOx): <20 ppm standard, lower emission optional
  • AHRI Thermal Efficiency (%): 94.7
  • AHRI Combustion Efficiency (%): 96
  • Fully condensing high-mass firetube boiler
  • Compact footprint
  • 500 to 6,000 MBH
  • Standard less than 20 ppm NOx
  • Ideal for variable flow primary systems
  • Standard dual-return connections
  • Robust, no flow tolerant design


The ClearFire®-CE (CFC-E) is a compact, high-mass, fully condensing hydronic boiler, capable of variable-flow pumping, allowing for maximum operating efficiency in a variety of system applications.

Ready to Ship & In Stock →


The CFC-E is up to 99% efficient due to its high-mass firetube construction with AluFer® firetube technology. The burner design offers inherent low emissions with <20 ppm NOx standard, helping meet emissions reduction goals.



  • Product Overview
  • Related Resources
  • Applications
  • High-mass design in a compact footprint, ideal for retrofit applications
  • Duplex stainless steel construction
  • Dual-temperature returns for additional energy savings potential
  • Falcon boiler control with lead-lag capability up to 8 boilers
  • Quiet operation, <70 dBA sound level at 3 feet
  • Low waterside pressure drop for reduced pumping energy requirements
  • Hinged burner for easy access
  • Thermal shock resistant
  • cULus listed


The ClearFire®-CE (CFC-E) is a fully assembled, high-mass firetube condensing boiler with a large-water-volume pressure vessel. The high-mass design equates to a low pressure drop, reducing pumping energy with no minimum flow requirements. The pressure vessel is also thermal shock proof, capable of high-delta-T system designs to maximize condensing and reduce flow rates. The highly effective fireside heating surface with industry leading AluFer® tubes leads to superior efficiencies in all operating conditions. The modulating, premix burner control automatically adjusts the air/gas mixture for maximum burner efficiency. The linkageless burner provides fully modulating turndown without the use of complex air/fuel mixing valves. The dual-return connections have the ability to increase condensing in the boiler and raise efficiencies by 6%+ more than a single-return boiler. The ClearFire-CE provides the reliability and longevity that customers expect from Cleaver-Brooks. The CFC-E is designed to leverage the advantages of primary-variable-flow pumping systems with a small overall footprint, offering system flexibility and true operational efficiency without compromise.

CFC-E Available and Ready to Ship Now! →


Controls Strategies for Maximizing Condensing Boiler System Efficiency →

Learn basic boiler control strategies and staging methods to maximize boiler operating efficiencies.

Why Ultra-High Turndown Is Bad For Hydronic Condensing Boilers →

Learn about optimized system efficiency, why matching boiler and pump turndown is critical to maintain the delta T and maximize efficiency.

ClearFire-CE Advantage Video

ClearFire-CE Advantage Video →


Alufer Technology Video →

Dual Return Advantage Video →

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