The disclosure relates to a thermostatic mixer, including a device for the dynamic regulation of cold water flow which supplies the mixer. of from 2 to less than 12 mm2s in combination with a Group IV base oil having a kinematic viscosity of at least 38, the difference in kinematic viscosity between the Group I and Group IV oils in the blend being at least 30 mm2s in combination with a detergent. The first frame member includes a slot extending along the first frame member. The first and third signal lines are electrically connected to the first via hole. Moreover, the data control circuit has a data saving control function whereby it, via a debugging port of a volatile memory storing data to be processed by the electronic circuit, saves that data.