Temperature sensing means

摘要

A water heater e.g. a shower unit has a temperature sensor (diode 10) providing a voltage which is compared with a reference voltage. This difference determines the selective switching on/off of the heating elements 1. The elements may have different power ratings (e.g. in the ratio 1:2:4:8) and are operated to avoid multiple and rapid switching on/off of the elements. The heater has a housing with an on/off valve 11 and a reduction valve at the water inlet and the temperature sensor 10 at the water outlet.