Preassembled pump group for regulation and circulation of mixed fluid at variable temperature. Allows the circulation of the thermal fluid, coming from the primary circuit, by adjusting its temperature by means of a motorizable mixing valve. It is used in general heating, air-conditioning and radiant panel systems with flow temperature regulation based on room and outside temperature (also called outside or weather or climate compensated control). The group is composed of flow/return shut-off valves, motorizable mixing valve, flow/return temperature gauges, check valve, flanged connections for single or twin pumps, thermal insulation. All the groups are reversible (the flow line can be exchanged with the return line).