Abstract: In a hydronic heating system having a boiler hot supply water line and boiler return water line, a main hot supply water circulation loop from the boiler supply water line to the boiler return water line and one or more satellite stations in series along the main loop, for a satellite station: a satellite injection water connection and a satellite return water connection along the main loop; a satellite distribution station including one or more satellite heating loops; a satellite supply header and satellite return header at opposite ends of the satellite heating loops; a satellite station pump having an input and an output for pumping satellite water from the satellite return header to the satellite supply header so that satellite water flows through the satellite heating loop(s); a satellite injection water line from the satellite injection connection to the satellite pump input; a satellite return water line from the satellite pump output to the satellite return connection along the main loop; and a therm