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Make-up Air Systems

Indirect Indoor Separated Combustion Make-up Air (DBS/DCS)

The Modine indoor separated combustion duct furnace with blower and/or cooling sections was designed for use with a building’s heating, heating/ventilating/cooling and make-up air systems. Modine separated combustion duct furnaces are specifically designed for buildings with hostile atmospheric conditions, such as high humidity or negative pressures. Available in 17 model sizes, the unit covers a wide variety of applications. They have input ranges from 75,000 to 1,200,000 Btu/Hr and can operate on either natural or propane gas. The airflow ranges from 556 to 14,500 CFM and the airflow direction can be specified when ordering the unit. The unit can be provided with a cooling coil section with either a factory installed DX or chilled water cooling coil or the coil can be provided by others.


  • Designed to fit into existing architectures
  • Separated combustion protects your investment in high humidity or negative pressure conditions
  • A low-cost option for make-up air
  • Extensive airflow range
  • Accessories such as a cooling coil section increase system versatility

Standard Features:

  • Available in 17 model sizes (input ranges from 75,000 to 1,200,000 Btu/Hr)
  • Natural or propane gas
  • Airflow ranges from 556 to 14,500 CFM (airflow direction can be specified when unit is ordered)
  • 18-gauge insulated aluminized steel blower cabinet with a baked-on polyester powder paint finish on exterior casing parts
  • Blower performance up to 3.0” W.C. external static pressure

Optional Features:

  • Unit can be provided with cooling coil section (either factory installed DX or chilled water cooling coil, or coil can be provided by others)
  • Double wall construction for blower and/or cooling cabinet
  • 2-position, modulating, building pressure sensing, 3-position, building management (0 - 10 Vdc or 4 - 20 mA input) damper actuators
  • Blower and motor vibration isolation
  • Units are third party certified by ETL