41D Barberi® motorizable mixing valves allow the mixing between two fluids (e.g. hot and cold water) to get the desired temperature. They are used in heating and cooling systems, central heating systems, heat generators (wall-mounted boilers, solid fuel generators, heat pumps). The mixing is obtained through a shaped rotor that regulates the passage of the fluids. The rotary mixing valves can be adjusted manually or by means of an electric actuator. Features of these valves are the running nut for pump connection, the male connection to the manifold and the by-pass device on the return. The by-pass on the return improves the regulation especially when electrical actuators are used.