Hydraulic Separator, Manifold, or Combined Unit: What to Choose and When

In a boiler room with multiple circuits, hydraulic decoupling is essential. The market offers three solutions that are frequently mixed up. **Hydraulic Separator** A [hydraulic separator](/catalog/hidravlichni-rozdilnyky) decouples the boiler circuit from the secondary circuits in terms of flow rate. If the combined flow demand of the secondary pumps exceeds the boiler output, the excess passes through the separator without entering the circuits. This protects the boiler from operating at insufficient flow and from thermal shock. The separator itself does not distribute flow between circuits. **Distribution Manifold** A [manifold](/catalog/rozpodilchi-kolektory) splits a single flow into several circuits but does NOT hydraulically decouple them — the circuit pumps still influence each other. A manifold is appropriate when circuits have similar characteristics, or when used alongside a hydraulic separator. **Combined Manifold with Hydraulic Separator (KGS)** The [KGS](/catalog/kolektory-z-hidrostrilkoyu) series combines both functions in a single body: it both distributes flow between circuits and decouples them from the boiler. This is the most compact solution for boiler rooms with 2–6 circuits. For typical residential applications, the same concept is embodied in [BOX2 / BOX3](/catalog/termojet-box) modules. **Selection Guide** - Single circuit — no decoupling needed. - Multiple similar circuits — manifold. - Multiple circuits of differing capacity + boiler protection — KGS or hydraulic separator + manifold. The wrong choice either costs money on unnecessary components or leads to unstable system operation. If in doubt, Termojet engineers will calculate the right configuration for your project.