Pre-assembled pump group for fixed point regulation and circulation of mixed fluid. Allows the circulation of the thermal fluid, coming from the primary circuit, by keeping the temperature at a pre-set value (fixed point) through the help of a mixing valve with thermostatic element. It is used in heating systems in general and radiant panel systems. The particular structure allows the immediate installation of a primary manifold on the left side, for the distribution at high temperature (radiators), and a secondary manifold on the right side, for the distribution at low temperature (radiant panels or radiators), by keeping them aligned. The group is composed of a pump, thermostatic mixing valve, flow LCD thermometers, manual air vent, fittings for primary and secondary distribution manifold. The group can be reversed to place the secondary manifold on the right or the left and, as a consequence, the primary manifolds on the left or the right.