The SR2221 is the motorized ball valve within Comparato Nello's SINTESI family, built for on-off isolation and flow diversion in residential and light commercial hydronic systems. The full-bore brass body with notched ball provides unrestricted flow when open and positive shut-off when closed. Quick push-in electrical connection and compact actuator profile simplify installation in tight boiler rooms and underfloor heating manifolds.

What control configurations are available?

The SR2221BA variant uses 2-point control: apply 230 VAC to the open terminal to drive the valve open, apply 230 VAC to the close terminal to drive it closed. Both terminals are never energized simultaneously — a relay-based controller handles the interlock. The 3-point variant adds a common return for systems that use SPDT controller outputs. An auxiliary free microswitch on the opening direction provides end-of-travel confirmation to the building management system.

When would I choose the 8 Nm version over the 5 Nm?

The 5 Nm actuator covers standard DN15–DN25 valves in clean water service. The 8 Nm version provides extra torque margin for valves that cycle infrequently and may develop mineral scale on the ball seat over time — common in hard-water regions. The trade-off is cycle time: 15 seconds for 5 Nm, 45 seconds for 8 Nm. For most zone-control applications, 15 seconds is fast enough; choose 8 Nm when torque certainty matters more than speed.

What is the bypass diverter variant?

The SR2221 is also available in a bypass (diverter) configuration with male-male connections and a notched ball that directs flow to one of two outlets without fully shutting off. This serves systems where flow must be maintained through either the primary circuit or a bypass leg at all times — a common requirement in boiler protection loops where the boiler must never see zero flow.