Series 4S

Series 4S

The Series 4S uses the very latest design techniques and standards. This means it is designed for low volumetric release rates and produces a higher efficiency due to the larger furnace and higher heat transfer design. The 4S is also a great option for Low NOx applications.

Design Firetube
Heat Exchanger 4 Pass
Standard Design Pressure Steam: 15 psi/150 psi
Standard Design Pressure Water: 30 psi/125 psi
Burner Customer Preference
Fuel Gas/Oil/Propane
Venting Forced Draft
Heating Surface- Sq Ft 5.0
Low Pressure Water Coil Yes
DOE/AHRI Status Certified


  • Four-Pass Full Wetback Firetube Design
  • Forced-Draft Firing with Oil (No. 2,4,5 or 6), Gas or Combination Gas/Oil
  • Produces a Higher Efficiency Due to the Larger Furnace and Higher Heat Transfer Design


  • Forced-Draft Firing With Oil, Gas or Combination Gas/Oil
  • Low- or High- Pressure Steam or Water
  • High Efficiency 4-Pass Design
  • Completely Packaged For “Same-Day” Installation
  • Heavy Steel Base Provides Adequate Stability Along with Shipping and Rigging Protection
  • Front and Rear Full-Sized Hinged Access Doors Are Standard and Secured with Non-Corrosive Brass Nuts
  • Access Door is Constructed of Durable, Lightweight Vacuum Formed Ceramic Fiber Making the Door Liner Weigh Less Than 5 Pounds
  • Handhole Clean-Outs Are Placed for Ease of Servicing
  • UL Approved Packaged Burners Are Trimmed and Wired to Assembled Gas Trains
  • 5 sq.ft./hp Rated Design, No Turbulators or Welded Tube-Ends
  • 4 Pass Wetback Scotch Boiler—to Learn More About Wetback Versus Dryback, Refer to Our Wetback Literature
  • Multitude of QC Checkpoints and Stringent Final Inspection Assures You of a Quality Product
  • No Proprietary Parts or Gaskets on the Boiler Trim or the Burner
  • Designed for Low Volumetric Release Rates of No More Than 130,000 btu/hr/cu.ft.
  • Fiberglass Insulated Aluminized Steel Jacket Is Finish Painted with High Gloss Burnham Blue Enamel
  • All External Trim Piping is Designed and Installed In Accordance with the ASME Code and Certified by an Independent Inspection Agency for Compliance

America’s Boiler Company

The Burnham Commercial Series 4S four-pass wetback scotch boiler was designed using our extensive boiler experience and is sold and serviced through the largest and most experienced network of sales representatives in the country. With a complete commercial product offering and unmatched sales and technical support, it’s no wonder why we are America’s Boiler Company!

Why Choose the Series 4S?

  • The design incorporates positive water flow circulation and maximum heat transfer to maximize ratings.
  • The handhole clean-outs are placed for ease of servicing.
  • The access door is constructed of durable, lightweight vacuum formed ceramic fiber – the door liner weighs less than 5 pounds!
  • All external trim piping is designed and installed in accordance with the ASME Code and is certified by an independent inspection agency for compliance.
  • The fiberglass insulated steel jacket is finish painted with high gloss blue enamel.
  • The front and rear full-sized hinged access doors are standard and secured with non-corrosive brass nuts.
  • The UL approved packaged burners are trimmed and wired to assembled gas trains.
  • The heavy steel base provides adequate stability along with shipping and rigging protection.
  • It is completely packaged and ready for “same day” installation.
  • The 5 sq.ft./hp rated design does not use turbulators or welded tube ends.
  • The multitude of QC checkpoints and stringent final inspection assures you of a quality product.
  • There are no proprietary parts or gaskets on the boiler trim or the burner.

Latest Design Techniques

The Series 4S uses the very latest design techniques and standards. Its furnace, the workhorse of the boiler, is designed for low volumetric release rates of no more than 136,000 btu/hr/cu.ft. The lower the release rates, the “easier” your boiler works. As your boiler works easier, less stress is put upon the steel, tube ends, refractory, etc., resulting in a longer lasting boiler. In addition to longevity, a larger furnace makes for ease in firing using any selected burner vendor. The Series 4S is also easily converted to a Low NOx product when needed.

Higher Efficiency

The Burnham Commercial Series 4S design produces a higher efficiency due to the larger furnace and higher heat transfer design. To determine the efficiency of your next job, contact your local Burnham Commercial representative.