A 4-Zone, Modular-built, “Neo-Gravity Hydronic Heating Appliance (TM)” as completed. (Beta #7). It uses 7-9 Watts of Delta-T ECM Circulation Energy when heating. The Boiler, Supply And Return Modules follow to detail construction. Note: A SSU-45 “Superstor” Indirect Water Heater has since been added to further optimize the system. View 4 Image 5 of 5