Thermostatic device with two levels of regulation operated selectively

Thermostatic device with two levels of regulation, comprising fluid-metering moving assembly comprising at least one valve (9, 10) and designed to move in a chamber (3) which has a first, fluid inlet, port, a second, fluid outlet, port and at least one third port, at least one of these three ports being surrounded by a valve seat (14, 15), the metering moving assembly being carried by part of a fluid-metering thermostatic element (7) which can move with respect to another part of the thermostatic element which part is arranged at least partially outside the chamber, the device also comprising a housing part in the form of a duct (1) for the passage of cooling fluid, one end of which opens into the chamber (3) via a valve seat (14) surrounding one port (6) of the chamber, which device is characterized in that it further comprises a thermostatic element (17) for adjusting the regulation threshold, having a moving threshold-adjusting part equipped with a moving stop (16) for the part of the metering thermostatic element (7) which is outside the chamber (3), and in that at least one region of the threshold-adjusting element comprising at least one portion of its fixed part and at least its moving part extends into the cooling fluid duct (1), and the said region contains heating means (18) designed to be switched selectively into one or other of two temperature states such that in the higher temperature state, the distance between the moving stop (16) and the seat (14) via which the duct (1) opens into the chamber (3), and thus the temperature for which this seat is opened by its valve (9) are respectively smaller and lower than in the other state.