Here is the Hoffman Data Book for Heating Engineers and Contractors, Second Edition compiled for the Hoffman Specialty Company in 1925. "The Hoffman devices which transfo...
Here are patents from 1922 for the Hoffman Specialty Company for their vapor heating system with differential loops. Thanks to Steve Pajek for finding and sharing these.
This document is from the sales department at the Hoffman Specialty Co. in 1926. It showcases Hoffman Valves and Controlled Heat Equipment with cutaway diagrams of how th...
This book, Hoffman Venting Valves for Every Purpose, was from the Hoffman Specialty Co. in 1918. It includes a lot of information about Hoffman valves for heating systems...