Low-loss header

A low-loss header is a large-bore heating-water header used to provide hydraulic separation between primary and secondary circuits. It creates a low-pressure path between flow and return connections so pumps on one side do not force unstable flow through the other side. In heat pump paperwork it may appear beside buffer tanks, volumisers, hydraulic separation, flow-rate checks and schematic drawings, but the label is not a heat-loss calculation, pipework design, MCS certificate, warranty approval or proof that the heating system is correctly designed.