Barberi® 4-way thermostatic mixing valves are devices with mixed water on the side and are used to adjust the water temperature. They are used in domestic water systems, heating circuits, central heating system, heat generators (wall-mounted boilers, solid fuel generators, heat pumps) and industrial water systems. Their function is to maintain constant the temperature of the the mixed water sent to users even if hot and cold water inlet temperatures or pressures vary. They can be used as 4-way valves (using the forth way for the boiler return) or 3-way valves (using a plug). If they need to be connected directly to a pump, versions with running nut on the mixed port are available.