Here's the whole Warren Webster line from 1943, along with some very clear explanations of how their heating system worked. After the catalog material, you will find the patent for the company's boiler return trap. Thanks to Gerry Gill for finding and sharing that one.
The Improved Webster Type "R" System of Steam Heating is a service bulletin from Warren Webster and Company (The Pioneers of Vacuum Steam Heating), established in 1888.
This manual was created by O-E Specialty Manufacturing Co. and outlines how to install the "O-E" Perfect System, which is a Vapor Vacuum heating system.
Here is the original Installation and Operating Instructions and Parts List for The H.B. Smith Company's Oil Fired Cast Iron Hot Water Boilers (No. OHB-13W). This is esti...