509 Series Boiler

Johnston Boiler Company

For many years, there were two choices in the industry – a 4-pass dry backed boiler, or a 3-pass water backed boiler. A 4-pass would have a higher efficiency and higher maintenance costs associated with frequent refractory repair, while the 3-pass water backed required less maintenance and offered less efficiency. That all changed in 1978 when Johnston introduced the first packaged 4 pass water backed boiler. Now, a customer could have the best of both world’s – water backed reliability with 4 pass design efficiency.

Every Johnston 4-pass maximizes effective heat transfer using a full five square feet of heating surface per BHP, while at the same time eliminating tube sheet stresses and costly maintenance repairs that are common with dry backed designs.


For more information and to order great products like this from Patriot Industrial Technologies, contact us today!

Greg McGuire




Download the brochure here.

For more info on Johnston Boilers, visit https://www.johnstonboiler.com/products/pftj-4-pass-steam/.