A water heater may operate according to different modes. The water heater may include a storage tank configured to store water, at least one sensor configured to sense a temperature of the water and a temperature related to an outside of the water heater, a first heater assembly (comprising a heating element) configured to heat the water, a first controller configured to control the first heater assembly, a second heater assembly (comprising a heat pump system) configured to heat the water, an inverter connected with the heat pump system, and a second controller configured to control the heat pump system by adjusting an output frequency of the inverter.

A system includes a heater bundle having at least one heater assembly with a plurality of heater units. At least one of the heater units defines at least one independently controlled heating zone, and a plurality of power conductors are electrically connected to the heater units. A power supply device includes a controller configured to modulate power to the at least one independently controlled heating zone through the power conductors, and the controller is configured to calculate temperature within the at least one heater unit based on a predefined model and at least one input, and the controller modulates power to the at least one heater unit based on the calculated temperature.

A heater system includes a heater bundle. The heater bundle includes a plurality of heater assemblies. Each heater assembly includes a plurality of heater units and an insulating material, and each heater unit defines at least one independently controlled heating zone. The heater bundle includes power conductors electrically connected to each of the independently controlled heating zones in each of the heater units. The heater bundle includes a power supply device configured to modulate power to each of the independently controlled heater zones of the heater units through the power conductors. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

A heater system includes a heater bundle. The heater bundle includes a plurality of heater assemblies. Each heater assembly includes a plurality of heater units and an insulating material, and each heater unit defines at least one independently controlled heating zone. The heater bundle includes power conductors electrically connected to each of the independently controlled heating zones in each of the heater units. The heater bundle includes a power supply device configured to modulate power to each of the independently controlled heater zones of the heater units through the power conductors. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

A low leakage current fluid heater and systems and methods thereof. The fluid heater has a configuration whereby a heating element is isolated from a fluid channel so as to leak into fluid passing through the channel an allowed amount of leakage current. Fluid passing through the fluid heater can be heated to a desired temperature. A controller can provide control signals to driver the fluid heater to the desired temperature and maintain the temperature at the desired temperature.

An electronic continuous-flow heater for heating a liquid includes an electrically heatable heating channel arrangement with at least one electric heating element, an electronic control system including at least one microprocessor configured to electrically control the heating element, and a display device connected by means of the electronic control system. The display device is designed as a bistable digital display such that the display content remains visible even in the absence of the display supply voltage of the display device.

A heater system includes a heater bundle. The heater bundle includes a plurality of heater assemblies. Each heater assembly includes a plurality of heater units and an insulating material, and each heater unit defines at least one independently controlled heating zone. The heater bundle includes power conductors electrically connected to each of the independently controlled heating zones in each of the heater units. The heater bundle includes a power supply device configured to modulate power to each of the independently controlled heater zones of the heater units through the power conductors. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

A low leakage current fluid heater and systems and methods thereof. The fluid heater has a configuration whereby a heating element is isolated from a fluid channel so as to leak into fluid passing through the channel an allowed amount of leakage current. Fluid passing through the fluid heater can be heated to a desired temperature. A controller can provide control signals to driver the fluid heater to the desired temperature and maintain the temperature at the desired temperature.

A method of controlling a heating system is provided that includes having at least one heater assembly, the heater assembly comprising a plurality of heater units, each heater unit defining at least one independently controlled heating zone, supplying power to each of the heater units through power conductors electrically connected to each of the independently controlled heating zones in each of the heater units, and modulating power supplied to each of the independently controlled heating zones. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time, or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

In a method for operating a heating device, fluid is initially introduced into a fluid chamber, then the heating elements of the heating device are switched on and a leakage current is detected as a temperature-dependent current flow through a dielectric insulation layer. A supply voltage of the heating devices is measured and is taken into account in an evaluation of the temperature at the fluid chamber as a function of the leakage current. The leakage current is converted into a leakage voltage by means of a resistor, which is then divided by the measured supply voltage. Subsequently, the quotient obtained may be multiplied by a compensation value in order to obtain a normalized leakage signal, which is normalized to a base value of the supply voltage. The normalized leakage signal is used, if a particular absolute value of the leakage signal is exceeded or if a particular slope of the profile of the leakage signal is exceeded, in order to top up the fluid chamber with more fluid and/or to reduce the heating power of at least one heating element.