A water heater system includes a water heater having a first water outlet and a second water outlet. The water heater system further includes a flow detection device coupled to the first water outlet to detect a water flow through the first water outlet. The water heater system also includes a flow control valve fluidly coupled to the second water outlet. The flow control valve is configured to control a flow of water through the second water outlet based on whether the water flow through the first water outlet is detected by the flow detection device.

For controlling energy transfer (Q) of a thermal energy exchanger of an HVAC system, a control system determines flow-dependent model parameters (M) for modelling performance of the thermal energy exchanger, using a plurality of measurement data sets, each measurement data set including for a respective measurement time a value of a measured flow of fluid (act), a value of a measured supply temperature (Tsup) of the fluid, and a value of the measured return temperature (Tret) of the fluid. The control system calculates an estimated energy transfer (Qest) of the thermal energy exchanger, using the flow-dependent model parameters (M), and controls (S4) the energy transfer (Q) of the thermal energy exchanger by regulating (S5) the flow of fluid () through the thermal energy exchanger, using the estimated energy transfer (Qest).

A hydronic system (HS) that comprises at least one hydronic circuit (HC) and a control (CT) for controlling the operation of said at least one hydronic circuit (HC) via a control path (CP), whereby said control (CT) comprises a feed forward controller (FFC). Operation of the system is improved by the hydronic system (HS) further comprising a control improvement path (CIP) running from the at least one hydronic circuit (HC) to the control (CT). Due to the control improvement path (CIP), the control (CT) can be improved in the case of the hydronic system (HS) becoming instable and/or showing poor system control.

A heat exchanger includes a burner configured to burn a combustible gas to produce heat, a heat exchanger configured to receive the heat from the burner, a flow sensor configured to measure a flow rate of a coolant passing through the heat exchanger; and a controller comprising processing circuitry. The processing circuitry receives flow data from the flow sensor and controls a firing rate of the burner based on a predetermined relationship between a differential temperature of coolant flowing through the heat exchanger and the coolant's flow rate.

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 water heating control system has a tank for holding a volume of water heated by a heater and having a hot water outlet and a cold water inlet connected to a main water supply whereby hot water removed from the hot water outlet is replenished with cold water. A temperature sensor provides a temperature signal indicative of water temperature in the tank, and a control unit monitors the water temperature based on the temperature signal and is responsive to selection of a Sabbath mode of operation for periodically actuating and de-actuating the heater while maintaining an average water temperature to less than a permitted preset threshold. In Sabbath mode the control unit closes a shut off valve connected to the water inlet when the heater is actuated and opens the shut off valve when the heater is not actuated.

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 including a water entry path, a heat exchanger, and a hot water output path and an outer path bypassing the hot water supply faucet, as being combined. A controller stores as an actual flow rate value for each immediate hot water supply operation mode, a flow rate detection value by a flow rate sensor at predetermined timing, and calculates a flow rate learning value based on a plurality of stored actual flow rate values. When the flow rate detection value becomes larger than a criterion value set in accordance with the flow rate learning value, use of the hot water supply faucet is detected and the circulation pump is deactivated.

The purpose of the present invention is to provide a hot water supplying apparatus that enables a user to conveniently execute a hot water control function in a location where a faucet is located, and a method for controlling the same. The hot water supplying apparatus for achieving said purpose comprises: a flow rate detection unit for detecting a flow rate change of water supplied by turning a faucet on/off and outputting a flow rate signal; and a control unit for, when the flow rate detection unit detects a flow rate change in a specific pattern, controlling a preset hot water control function to be executed according to the flow rate change pattern.