Whether a plumbing system is necessary depends on what the current distributor looks like. Are the valves already electrically controlled? Then not.
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In addition to the actuator, you also need the corresponding number of actuators (HmIP-VDMOT), which carry out the actual control, and the appropriate adapter rings to connect the actuator to the heating valve.
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Adapters under Accessories
As well as one or more wall thermostats. You also have to decide whether you want to control the heating purely by wall thermostat or more conveniently by app or computer. Then you need a HomematicIP access point or a CCU3 as a central control unit.