Caleffi's 644 Series Motorized Ball Zone Valves provide zone control for applications requiring high flow rates and high close-off pressures. Standard mixing and diverting models are available as well as a unique three-way bypass configuration that switches between primary and bypass flow ports to prevent pump dead heading. An energy-efficient 24-volt three-wire actuator provides traditional two-position control action, or can be combined with any three-wire floating controller for outdoor reset on radiant systems.

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