One of the earlier gravity-hot-water-heating devices. Water would stratify in the horizontal main, with the hottest water rising to the top of the pipe. It left the tee and flowed to the radiator though the tee's top tapping. Cooler water from that radiator entered the same tee though the side tapping. Interesting things happen when you add a circulator to a system that has these tees. Thanks to Gerry Gill for finding and sharing the patent.
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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...