SAV Ft40: Solving the Last of the Unbalanced Systems

SAV Systems have together with our technology partner Cimberio, created an interchangeable pressure independent and pre-settable balancing cartridge (PI-UFH) for underfloor heating manifolds.

Traditional underfloor heating (UFH) manifolds are notoriously difficult to balance, especially when designed for a 10˚ C temperature differential (low flow rates). Typically, a flow limiter is integrated with a flow gauge on the manifold with a minimum practicable settable flow rate at 1 l/m. However, due to reductions in building heat demand lower flow rates are often required.

Different room sizes and circuit lengths will make the balancing of underfloor heating manifolds even more difficult, where even static full-load balancing may not be achieved. Any unbalanced circuits will exaggerate heat up times and over- and undershoots, leading to poor indoor comfort for the occupants.

The preferred solution for poorly balanced systems is to use Differential Pressure Control Valves (DPCV). In essence, a DPCV provides a controlled flow of fluid by counteracting system pressure variations due to changes in heating demand.


It’s widely accepted that Pressure Independent Control Valves (PICVs) are necessary for the proper balancing and control of fan coil heating systems. Subsequently, the technology has been integrated in radiator valves, with Pressure Independent Thermostatic Radiator Valves (PI-TRVs) becoming Best Practice for the balancing of radiator systems.

We used this concept and implemented it within underfloor heating manifolds, allowing for easier and more reliable balancing. Similarly with PI-TRVs, the PI-UFH cartridge incorporates a (low) flow limiter (pre-setting) protected by an integral DPCV. This guarantees the required flow to each zone despite varying load conditions and fluctuating pressure. Hence, a fast-commissioning process is achieved through an automatic balancing of the underfloor heating circuits.

To reduce costs, improve energy efficiency and create a comfortable indoor environment; the balancing of underfloor heating systems will need to be improved. With the introduction of the SAV Ft-40, underfloor heating systems can now be effectively balanced.

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