Firetube Boilers

Firetube Boilers

Firetube boilers are a widely used commercial boiler design that is capable of generating steam or hot water for various applications. These boilers derive their name from the design of their heat transfer surfaces, where hot gases pass through an array of furnace/fire tubes which are immersed in water.

The basic construction of a firetube boiler consists of a horizontal cylindrical pressure vessel with  a series of furnace/fire tubes that run lengthwise of the vessel. The combustion gases produced by the burner pass through these tubes heating the surrounding water. As a result, the water outside the tubes is transformed into either steam or hot water, which can then be used for multiple purposes.

The process within a firetube boiler works as follows:

  • Fuel combustion: A fuel source, such as natural gas or ULSD #2 oil is ignited in the combustion chamber, also known as the morrison tube. The combustion process generates hot gases with a significant amount of heat energy that a forced air fan pushes through the fire tubes.
  • Heat transfer: The hot gases produced from the combustion flow through the tubes that are immersed in the water-filled pressure vessel. As the furnace gases pass through the tubes, the heat energy is transferred to the water.  Thermal efficiency can be improved by incorporating multiple “gas passes”, wherein the furnace gas will travel multiple times across the length of the boiler.  For instance, a 2-pass firetube boilers would have a flue gas outlet at the burner-end of the boiler, whereas a 3-pass boiler would have the flue gas outlet at the rear of the boiler.; the latter resulting in more time to transfer energy before existing the boiler proper thereby increasing thermal efficiency.
  • Steam or hot water generation: The firetube boiler design can be tailored to produce either saturated steam or hot water.  Hot water applications are typically limited to about 25-35°F of ΔT (temperature rise) across the boiler proper. For higher temperature limits, please see our LaMont® High-Temperature Hot Water Generators (HTHWG).

Available Firetube Boilers

For Rent, Sale, or Lease

700HP, 150P

Superior Boiler Works


700HP, 150P - (3 QTY)



300HP, 15P



100HP, 15P


Indeck provides the following goods and services as they relate to firetube type boilers.

  • Aftermarket sales support on the historic Volcano Boiler (now Indeck Boiler Corporation) “Starfire” firetube boiler product line.
  • Limited inventory of stock boilers from multiple manufactures.
  • Rental boilers including skid-based units as well as Mobile Boiler Rooms, the latter of which include onboard boiler feedwater equipment as well as blowdown and chemical feed ancillary equipment pre-assembled in and enclosed multi-axel trailer.
Skid Mounted Firetube Boiler

Indeck Solutions, Systems, & Services

At the heart of our commitment lies the dedication to providing our customers with the power they need, precisely when and where it matters most. With an extensive background in the industry, unwavering stability, and formidable financial strength, we possess the capabilities to deliver comprehensive solutions to any challenge. As a leading provider in the industry, the Indeck Group stands as a singular source supplier of cutting-edge boiler systems, recognized among the foremost manufacturers of industrial steam boilers in the United States. Our portfolio encompasses tailor-made boiler systems and a wide range of industrial steam boilers available for both purchase and rental. To inquire about steam boiler rental, please contact us at 847-541-8300 or explore our product line below

An Engineered System to Reduce NOx Emissions

The I-SCR System was designed by Indeck to help reduce the emissions of nitrous oxide (NOx) on industrial boiler systems. This system uses a selective catalytic reduction process that converts nitrous oxide emissions in the combustion flue into harmless nitrogen (N2) and water (H20) without forming secondary pollutants.

Burner Management and Combustion Controls

Nearly half a century of field experience in packaged industrial boiler systems has led to the development of our burner management and combustion control systems. Our in-house engineering, UL listed panel shop, and large component inventory allow us to develop custom systems very quickly.

Emergency Trailer-Mounted Deaerators

We provide emergency water treatment trailers for many purposes including use with rented boiler systems, in-plant deaerator inspections, and equipment expansion or replacement. Our trailer-mounted deaerators will meet your flow rate and water quality requirements to keep the plant on-line.

Boiler Accessories

We understand the importance of properly integrated accessories to complete industrial steam boiler systems. Our engineering staff ensures that the required interface is in place so that the overall boiler system performs at optimum efficiency.

Boiler Parts

At Indeck, our top priority is to keep our customers up and running at maximum efficiency. We have over $25 million worth of boiler parts in stock to help reduce downtime as well as improve and maintain the efficiency of your boiler system and accessories.

Indeck 24/7 Emergency Boiler Rental

With Indeck, you can trust in our ability to swiftly address your emergency needs and provide the necessary power solutions, keeping your operations running smoothly and minimizing downtime. Count on us for prompt and dependable assistance with all your emergency and power requirements.