A washer comprises: a washing tank (2); a detector (3) for the water level in the washing tank (2); a washer (1) electronic control unit (4), the electronic control unit (4) being electrically connected to a first and a second electric conductor (51, 52) which in turn can be connected to a movable switch (5) controlled by the detector (3) depending on the water level in the washing tank (2). The first and second electric conductors (51, 52) transfer to the electronic control unit (4) at least three different items of information relating to the water level in the washing tank (2). Said transfer is carried out according to a binary logic linked to whether or not an electric current passes in each electric conductor (51, 52). Each item of information corresponds to one of the corresponding different configurations of the switch (5).