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Cleaver-Brooks FLX Premix Boiler

Cleaver-Brooks FLX Premix Boiler

  • Steam or Hot Water
  • 75-250 HP (3,150-10,500 MBH Input)
  • Natural Gas, Propane
  • 15-250 psig Design Pressure
  • Premix Burner Technology
  • Standard sub-20 ppm NOx, Optional sub-9 ppm NOx
  • Field Erectable


The FLX Premix (FLXPM) steam or hot water boiler achieves best-in-class combustion performance with low emissions. Premix burner technology enables the boiler to attain <20 ppm NOx without FGR and <10 CO as standard on natural gas. The modulating burner control automatically adjusts the air/gas mixture for maximum efficiency and optimum turndown.

  • Up to 5:1 turndown
  • Small footprint
  • Thermal shock resistance
  • Hinge-mounted burner and removable panels allow easy access for service and maintenance
  • 25-year limited pressure vessel warranty

Flexible Watertube Boiler Animation

The FLXPM integrates a servo-driven, fuel-input control valve with air-input control via a variable-frequency-driven fan for precise fuel/air ratio control. The field erectable option allows you to replace boilers in tough to access spaces. The pressure vessel is assembled at the factory and hydro-tested. During the disassembling, the tubes are matched marked for easy installation on site. The boiler is a 5-pass cross-flow water tube design. This allows for maximum heat transfer thru every pass. The gas flow design of the FLXPM does not require baffles which lowers maintenance costs throughout the boilers life. A fully water-cooled furnace reduces heat loss from the furnace section. The design eliminates the need for costly maintenance on the side or rear insulation, which reduces the total cost of ownership.



Cleaver-Brooks is the industry leader in providing energy-efficient, low-emissions boiler room products. With the power of total integration, only Cleaver-Brooks can offer a complete boiler room solution that is designed, engineered, and manufactured (by one company) to work seamlessly together.
By selecting Cleaver-Brooks, you can forget about having to cobble together a boiler room with different manufacturers and hoping they’ll all work together. Instead Cleaver-Brooks will provide the boiler, burner, controls and all accessory equipment to remove the headaches and provide one source of accountability for your boiler room.
Cleaver-Brooks offers an extensive range of steam boilers from 10 horsepower to 1,000,000 pounds of steam per hour including firetube, industrial watertube, flexible watertube commercial, electric, and heat recovery boilers.

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