A thermostatic mixing valve with disinfecting facility

A thermostatic mixing valve including: a body comprising: a first fluid inlet; a second fluid inlet; an outlet; and a thermostatic element connected to a return spring and a piston; an intermediary body connected to the body, the intermediary body configured to support a housing containing an overtravel spring, the overtravel spring configured to resist a force applied by the thermostatic element during movement thereof; and a plunger extending into the housing, the plunger interacts at its end with the overtravel spring, wherein: in a normal operational condition, movement of the thermostatic element assists with moving the piston such that movement of the piston controls fluid flow from the first fluid inlet and the second fluid inlet to the outlet in order to achieve a relatively constant temperature output; and rotating the plunger: provides a thermal disinfection condition whereby the plunger adjusts the resistance applied onto the thermostatic element from the overtravel spring, thereby allowing the return spring to overcome the overtravel spring, despite the thermostatic element being subjected to a higher temperature, or allow the thermostatic element to extend without engaging the plunger, such that hot water having a temperature higher than the relatively constant temperature output flows through the thermostatic mixing valve to thermally disinfect the valve; and allows the valve to return to the normal operational condition after the thermal disinfection condition.