HEATING ELEMENT ASSEMBLY

摘要

An integral water heating assembly for mounting to the tank wall (3) or bottom of a water heater. The integral water heating assembly in accordance with the invention is able to detect conditions such as overheating of the heating element or boil dry conditions and accordingly switch off power to the heating element. This sensing and switching of the electrical power to the water heating element is accomplished without any sensing means external to the water heating assembly housing. The water heating assembly (1) includes a sheathed heating element (5) having ends which pass through apertures in the housing (2). The heating element (5) preferably has a number of U-shaped bends and an intermediate section which contacts the housing at a point (6). The electrodes (7) of heating element (5) are connected to a source of electrical energy through a control unit (8). The control unit includes a switching means (9) for turning the power on and off, the switching means being controlled by a silicon chip (10). The contact between the heating element (5) and the housing (2) is towards the top of the housing. A temperature input to the controller (10) is provided by a temperature sensing means (11) which is mounted between the control unit (8) and the point of contact (6) between the heating element (5) and the housing. The switching means (9) is preferably a triac which is in thermal contact with the internal surface of the housing.