Here is an interesting presentation of extended heating surface in a boiler, featuring National Radiator Company's No. 2 Oil-Fired Boiler. Size matters. This is from 1941.
This document contains the complete illustrated instructions for installing the Hercules Steam and Hot Water Heating System, a boiler manufactured by Sears, Roebuck and C...
This document contains the manufacturer's instructions for the HB Smith Series M450L Mills Water-Tube Boiler for automatic firing with oil or gas (Steam, Vapor, or Water ...
This document contains the jacket assembly instructions for the HB Smith Series 45 Mills Boiler (circa 1979).