Model 4

  • Steam or hot water
  • 1.5 to 6.0 MMBTU/hr
  • Natural gas, #2 oil, propane, digester
  • 15 to 500 psig on steam (special to 675 psig) on steam
  • 140 psig on hot water standard with option to 450 psig @ 410F

The Model 4 membrane wall watertube boiler is a high-performance, super-compact unit designed specifically to fit through a doorway.


The Model 4 is a compact unit that reduces floor space by 50% with weight savings of 40% while providing steam or hot water output from 35 to 143 horsepower. The complete package fits through a standard doorway, ideal for replacement of existing units with ease of installation and minimal cost. Each unit is fully assembled, tested, CSA approved, and shipped ready for fuel, water, electrical, and breaching hookup.


  • Fits through standard doorway
  • Integral burner for maximum efficiency
  • Ease of installation
  • High-pressure design up to 600 psig
  • UL-listed package
  • Quiet: <70 dBA sound level

Solutions & Applications


  • Process Steam
  • Building Heat

Customer & Performance