Series 500 Boilers



Wet back design eliminates, costly deteriorating refractory rear doors and baffles between flue gas passes.

Wetback Construction

Available with Low NOx

Skid Mounted Modular Packaged

Series 500 Boilers

30-1,500 HP


1,004-50,213 MBTU/HR

Steam To:

300 PSI

Hot Water To:

60 PSI

The Hurst 500 Series four-pass wetback scotch marine boiler is an ideal choice for all commercial and industrial applications when engineering mechanical systems using the latest HVACR technologies. The Hurst 500 Series boiler provides fuel efficiencies that exceed most four-pass designs. Having no large refractory rear door, these boilers allow one technician easy access to all tubes. The boiler front doors can be opened without removing any burner components or controls.

  • Factory Assembled, Prewired and Tested
  • No Field Assembly Required
  • UL Listed Boiler/Burner Packages
  • Fully Assembled, Prepiped, Prewired, Pressure Tested Gas Trains
  • Complies With ASME, UL, CSD-1 and ASHRAE Standards
  • High Efficiency, Low Stack Temperatures
  • Customer Service Support Through National Network of Sales, Service, Start-up, Training and Parts By Factory Representatives

Wetback Advantage

Dryback boilers are subject to deteriorating rear refractory, leaking baffles, leaking door seals, and often found with a heat-stressed rear tube sheet. Fragile refractory baffling and door seals will require continuous monitoring, maintenance, and replacement, costing thousands of dollars in materials and specialized labor costs over the life of the boiler. In addition, broken baffles and leaking seals will short-circuit the boiler’s gas flow, causing high stack temperatures and lowering efficiency until repairs can be made. This can bring your production process to a costly halt.

All of those frustrating problems have been designed out of the Hurst Series 500 Wetback. It has a full wetback radiant heat transfer area that promotes superior internal water circulation and rapid heat absorption. Separate rear tube sheets allow each pass of tubes to expand and contract at its own rate without tube-to-sheet stress. Tubes are mechanically rolled, flared and beaded, making any tube service a simple matter. The only rear refractory is a manway plug which allows access to the furnace for inspection.

Standard Features

Built in accordance with the ASME Code, the wet back design has proven to give much longer useful life cycles than dry back boilers.

Each unit is tested and inspected and registered with the National Board of Boiler and Pressure Vessel Inspectors.

Hurst Boiler utilizes state of the art computer design techniques in every boiler. This accounts for accurate calculations of construction materials and optimum utilization of the boiler"s performance criteria.

The Series 500 is designed for optimum fuel efficiency and has proven in certified tests to meet, and often exceed, the efficiencies of four-pass boilers.

Low Maintenance
There are no refractory baffles to replace or maintain. Elimination of these will result in thousands of dollars in savings.

Tube Sheets
The wet back has independent tube sheets with uniform temperatures. Three and four pass dry back boilers have tube sheets with large temperature variations and this results in premature tube failure and cracks in the tube sheets.

Easy Access
Since there is no large refractory rear door, one man can easily remove the rear cover plates for access to the tubes. Front doors can be opened without removing burner components or controls.

With computer aided design, Hurst has made the wet back a space saving workhorse without sacrificing the principle of 5 sq. ft. of heating surface per BHP.

Hurst uses name brand burner components with proven reliability. Every unit is boiler/burner compatible and tested at the factory prior to shipment.

Standard Steam Trim

  • Operating and high limit pressure control
  • Modulating pressure control (when appl.)
  • Water column with gauge glass, combination low water cut-off and pump control
  • Probe Aux, L.W.C.O. with Manual Reset
  • Steam pressure gauge, syphon and test cock
  • Stack Thermometer, Water column drain valve
  • Safety relief valve(s) per ASME Code

Standard Water Trim

  • Operating and high limit temperature control
  • Modulating temperature control (when appl.)
  • Probe type low water cut-off control with Manual Reset
  • Combination pressure and temperature gauge
  • Hot water return baffle for shock resistance
  • Safety relief valve(s) per ASME Code
  • Stack Thermometer