A conditioning or heating plant and a process of controlling the plant, wherein plant comprises at least one circuit for distributing a carrier fluid, having a delivery line, a return line, and a plurality of channels directly or indirectly connected to the delivery line and return line and configured for supplying respective environments to be conditioned and/or heated, at least one heat treatment central group placed on the circuit. The plant has, for each of the channels, at least one respective heat exchange unit and at least one flow-rate regulator.

An apparatus configured to regulate the circulation of a fluid in a thermal plant includes a differential pressure regulator, a three-way selection valve, and a two-way zone valve. The apparatus can be installed according to a plurality of installation modes, in which: the differential pressure regulator intercepts the delivery circuit or the return circuit of the plant; the two-way zone valve intercepts the delivery circuit or the return circuit; the three-way selection valve is operatively interposed between the delivery circuit and the return circuit; a first inlet/outlet terminal of the three-way selection valve is placed in fluid communication with a high-pressure inlet or a low-pressure inlet of the differential pressure regulator; a second inlet/outlet terminal of the three-way selection valve is in fluid communication with a point of the delivery circuit or of the return circuit; and a third inlet/outlet terminal of the three-way selection valve is in fluid communication with a respective point of the return circuit, if the second inlet/outlet terminal is in communication with the delivery circuit, or of the delivery circuit, if the second inlet/outlet terminal is in communication with the return circuit.

A system for heating an indoor environment comprising: a primary heat source for heating a heat transfer fluid; at least one remotely actuatable valve for stepped or continuous control of the flow rate of a heat transfer fluid through a return pipe outlet of a heat emitter; a pipe temperature sensor for measuring the temperature of a return pipe outlet of a heat emitter; an optional room temperature sensor for measuring the ambient temperature of an indoor environment; an optional user interface for receiving instructions from a user including at least one target ambient temperature; an electronic controller configured to receive temperature measurement information from each of the pipe temperature sensors and (optionally) temperature measurement information from each of the room temperature sensors, and further configured to provide control instructions to each of the remotely actuatable valves relating to flow rate control; wherein the electronic controller comprises a processor configured to determine the control instructions based at least in part on the temperature measurement information.