A water heater system and method of operating such a system are disclosed herein. In an example embodiment, the water heater system includes a heat exchanger. a heat source inlet by which heated heating fluid can be provided to the heat exchanger, a heat source outlet by which cooled heating fluid can be communicated from the heat exchanger, a water supply inlet by which supply water can be provided to the heat exchanger, and a water supply outlet by which heated water can be communicated from the heat exchanger. Additionally, the system includes a controller, a water supply outlet temperature sensor, a water supply flowmeter, and an actuator. The controller is configured to generate control signals based at least indirectly upon temperature measurements and flow measurements and to provide the control signals to the actuator to regulate a fluid flow of the heated heating fluid into the heat exchanger.

A heated water recirculation system includes a water heater having a water inlet and a water outlet. The heated water recirculation system further includes a flow detector positioned to detect inflow water flowing into the water heater through the water inlet. The heated water recirculation system also includes a controller configured to control operations of a recirculation pump based on a detection of the inflow water flowing into the water heater through the water inlet. The water heater is configured to provide heated water through the water outlet, and the recirculation pump is configured to circulate the heated water through the heated water recirculation system.

The water heater may be configured to execute a normal operation in which a heating means is continuously operated in an ON state in a case where a required heat quantity is greater than or equal to a minimum heat quantity. The water heater may be configured to execute an intermittent operation in which the heating means is alternately and repeatedly operated in the ON state and an OFF state repeatedly in a case where the required heat quantity is less than the minimum heat quantity. The water heater may be configured to change a distribution ratio of a flow control mechanism in the normal operation and in the intermittent operation. An operating speed of the flow control mechanism in the intermittent operation may be faster than an operating speed of the flow control mechanism in the normal operation.

In a heating and hot water supply device including a burning means, a first heat exchanger, a circulation passage for circulating a heating thermal medium, a circulation pump, a first bypass passage, a second heat exchanger for hot water supply, a hot water supply passage, a second bypass passage bypassing the second heat exchanger, a control unit, and an operating terminal, a distribution means is provided at a branching portion of the first bypass passage and is capable of adjusting its distribution ratio for heating, or hot water supply, or simultaneous heating/hot water supply, a display means of the operating terminal is capable of providing displays corresponding to various types of operation.

Device for carrying out a Shirodhara treatment in which a liquid is poured over the forehead of a person, whereby said device comprises an outlet for the liquid and a pump and a supply line running from said pump to said outlet, whereby said outlet is can move reciprocally in a regular manner, whereby said device is provided with a heating unit for heating liquid to a target temperature, whereby said heating unit comprises a heating element, whereby said heating element is disposed in or around said supply line, whereby said heating unit comprises a temperature sensor for measuring the temperature of liquid, whereby said device comprises a control unit to regulate the power of said heating element on the basis of the temperature measured by said temperature sensor.

A water heater has a water supply line, a heat exchanger in fluid communication with the water supply line, a heating element positioned proximate to the heat exchanger, such that when activated, the heating element conveys heat to the heat exchanger and thereby heating water supplied by the water supply line, an output line in fluid communication with the heat exchanger and configured to receive heated water therefrom, a flow sensor configured to cause the heating element to activate in response to sensing a predetermined water flow rate through the water heater, and a bypass flow line operably connected between the water supply line and the output line.

In an immediate hot water supply operation mode in which a circulation pump is activated while a hot water supply faucet is closed, a water heating apparatus forms an immediate hot water supply circulation path by an inner path and an outer path as being combined, the inner path including a heating mechanism including a combustion mechanism and a heat exchanger, the outer path bypassing the hot water supply faucet outside the water heating apparatus. The outer path includes a crossover valve. In the immediate hot water supply operation mode, a controller introduces intermittent combustion to control a detection temperature detected by the temperature sensor to a set temperature. In intermittent combustion, a minimum combustion state and a combustion stop state are alternately provided. In the minimum combustion state, a quantity of heat output from the combustion mechanism is reduced to a minimum value.

The present invention provides a method of operating a gas heater for water including the steps of: restricting a water flow to the gas heater; determining a first rate of a first gas heating for the restricted water flow; adjusting the gas heating to the restricted water flow; repeating the previous steps until a heated water has a temperature above a temperature threshold; removing the restriction to the water flow to increase the water flow; and determining a second rate of a second gas heating for the increased water flow. The present invention also provides a gas water heater which utilises such a method.

A scale adhesion prevention operation of a circulation pump operated in an instant hot water operation is efficiently and appropriately performed. An instant hot water circulation path is formed to bypass a hot water tap outside a hot water supply device and to pass through a heat exchanger inside the hot water supply device by operating a circulation pump when the hot water tap is closed. A controller performs a protection operation which operates the circulation pump when a first condition in which stop of the circulation pump is continued for a first time is satisfied and a second condition related to stop of a hot water supply operation is further satisfied.

A hot-water supply device includes a hot-water dispenser supplying hot-water, a hot-water supply path supplying the hot-water to a hot-water supply tap, a circulation path carrying out instant hot-water operation which circulates and heats the hot-water remaining in the hot-water supply path, a first clock repeatedly measuring unit times in which a pattern of hot-water usage of a user makes a round, and a flow rate sensor detecting the supply of the hot-water from the hot-water supply tap. The control portion detects, for each of the unit times and based on detection signals of the flow rate sensor, a time zone in which hot-water supply operation is carried out, and reserves, based on a time zone in a first unit time in which the hot-water supply operation is carried out, a time zone in a second unit time following the first unit time for carrying out the instant hot-water operation.