Johnston Water-Back 3 And 4-Pass Scotch Marine Boilers

The Johnston Water-Back 3 and 4-Pass Scotch Marine Boilers are the main products made by the Johnston Boiler Company. The Johnston Boiler Company has a long history of making boilers dating back to its founding in 1864 by J.W. Johnston a direct descendant of James Watt.

J.W. Johnston purchased a defunct boiler company in Ferrysburg, MI. in 1864 and reopened it as The Johnston Boiler Company providing boilers to the lumber industry along the shores of the Great Lakes. The company later expanded into providing boilers for the construction industry, locomotive, stationary, and marine boilers. The use of oil and gas in the 1920 had Johnston introducing a single furnace 2-pass water-back scotch marine boiler. In 1934 they introduced the 3-pass boiler, which became standard in 1942, in 1982 Johnston introduced the 4-pass water-back scotch marine boiler. From it’s many firsts in the industry Johnston can also boast where they have been, from helping to carve the Panama Canal, helping to build the Mackinac Bridge, making the worlds largest firetube boiler for use on oil drilling rigs, to even being used at the South Pole to bore through 1500’ of ice, Johnston has been there and done that. Today they are ready to provide the know-how providing the burners, boilers and equipment needed to bring your boilers into compliance with the new EPA MACT regulations.

Johnston Boiler Company’s main products of course is it’s 3 and 4-Pass Water-Back Scotch Marine Boilers. The 3-Pass Boilers are available in 1800-2500 HP Sizes, and the 4-Pass Boilers are available in 50-1600 HP sizes.  They can generate from 1,725 – 86,250 PPH of steam at pressures from 15 – 350 psig while reaching efficiencies as high as 90%. Each Johnston Boiler is custom engineered and custom built taking into account the customers needs and specs for size, fuel and equipment, then tested at the factory over its complete operational range from low fire to high fire to check the controls for safety and performance including the fuel/air ratio. Despite the custom engineering and build, most of the controls on Johnston Boilers are “Off The Shelf” lowering down time in the event of failures.

The design of the Johnston 3 and 4-Pass Water-Back Scotch Marine Boilers allows easy maintenance with their hinged an davited front and rear doors for access to the fireside tubes, and the manhole in the top for waterside access. The fan can be serviced through its swing away hinge without having to disconnect the burner or, fuel lines on many sizes from 100 – 1600 HP.  To ensure steam quality all boilers have a surface blow off tap with an integral dip tube for a surface metering valve, and a steam baffle under the nozzle outlet to assure dry steam output. The entire pressure vessel is covered with a 2” fiberglass insulation blanket and covered with a rust proof galvanealed steel jacket, with the front and rear doors using a ceramic fiber insulation blanket allowing minimal use of refractory. Johnston mounts its burner and controls on the front of the boiler with a NEMA 12 control panel as standard equipment. The J29 and 509 series are full modulation and can have turndowns of 10:1. gas piping trains  are equipped to meet UL but can also meet other standards as well to meet your specific needs, they have 2 pressure gauges, fuel input control valve, safety shut off valves, and shut off cocks along with contoured cam fuel flow control valves to provide reliable fuel/air ratios throughout the firing range. Oil piping trains for #2 – #6 oils have a fuel input control valve, safety shut off valves, suction strainer, oil pump, pressure gauge and regulator. When fuel oils are used that requires pre-heating equipment for that purpose if furnished either a steam or, water heater or an electric pre-heater.

The Johnston Boiler Company provides a warranty almost unmatched in the industry with a 15-Year Parts and Labor Warranty on the Major Pressure Vessel Components Including the Tube Sheets, Furnace, and Rear Combustion Chamber. Also provided is a 15-Year Parts and Labor Warranty on the Front and Rear Flue Doors. In addition Johnston Guarantees the Certified Boiler Efficiency and within one year of commissioning the boiler the efficiency is below the certified boiler efficiency Johnston will pay a rebate of $7500 for each 0.75% the boiler is below its certified efficiency.

For additional Information on Johnston Boilers you can visit the Johnston Boiler Company on-line, write to them at Johnston Boiler Company 300 Pine St. P.O. Box 300 Ferrysburg, MI. 49409-0300 or, call them at 616-842-5050.