Various implementations include a water heater system. The system includes a variable speed pump. The variable speed pump has having an inlet and an outlet. The system includes a heat exchanger, having an inlet and an outlet. The heat exchanger outlet is fluidically connected to the variable speed pump inlet. The system includes an output temperature sensor disposed downstream of the heat exchanger outlet. The system includes a controller configured to receive a first temperature reading from the output temperature sensor. The controller is configured to control operation of the variable speed pump to adjust an output flow rate in response to the first temperature reading. The controller is further configured to receive a second temperature reading from a recovery temperature sensor on a storage tank. The controller is configured to turn off the variable speed pump upon a determination that the second temperature reading has reached a maximum temperature.

A pump assembly includes an impeller (18), which for rotation is connected to an electrical drive motor (20) which can be driven in two rotation directions (A, B) and a valve (10) situated in an inlet of the pump assembly. The valve includes a valve element (48) movable between at least two switch positions and is connected for movement to a drive element (36, 60) subjected to the flow produced by the impeller (18). The valve element (48), in at least a first of the two switch positions, closes an inlet channel (44, 46) of the pump assembly (12) and is arranged such that the movement direction into this first switch position corresponds to the flow direction (S1, S2) through this inlet channel (44, 46). A hydraulic system is provided with two circuits and such a pump assembly. The valve serves as a switch-over valve between the two circuits.

A circulation pump assembly includes a first inlet (84), an outlet (80), an electric drive motor (30) and at least one impeller (68; 100) driven by the drive motor (30). The circulation pump assembly has at least one first flow path (26; 48) positioned in a connection between the first inlet (84) and the outlet (80) for increasing the pressure of a fluid. The circulation pump assembly has a second inlet (86). The at least one impeller (68; 100) has at least one second flow path (28; 50) for increasing the pressure of a fluid, which is positioned in a connection of the second inlet (86) to the outlet (80). A heating system is provided having a circulation pump assembly of this type.

The present disclosure pertains to a system configured to prepare and use prediction models for classifying images. Some embodiments may: obtain, via a system return temperature sensor, a system return temperature; obtain, via an appliance return temperature sensor, an appliance return temperature; and responsive to a determination that the appliance return temperature is greater than the system return temperature by at least a first threshold amount, decrease, via a hardware processor, a speed of the appliance pump.

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.

The present invention relates to a method of operating an electric motor-driven centrifugal pump (3) in a hydraulic system (4) having at least one self-controlled load, where a gradient (dQ.sub.akt/dt) of the volumetric flow rate (Q.sub.akt) of the centrifugal pump (3) is determined and the current set-point delivery head (H.sub.soll) of the centrifugal pump (3) is calculated from a mathematical operation on the gradient (dQ.sub.akt/dt) weighted with a gain factor (K) and the last specified set-point delivery head (H.sub.soll,alt). The operation describes a positive feedback between the set-point delivery head (H.sub.soll) and the volumetric flow rate (Q.sub.akt). The gain factor (K) is determined from a calculation instruction that is modified dynamically during operation of the centrifugal pump (3) taking into consideration the current operating point of the centrifugal pump (3) and taking into consideration a current and/or at least one past state of the hydraulic system (4).

A heating control method includes determining a first speed for an air circulation fan that corresponds with a temperature set point using a temperature map that maps temperatures to speeds of the air circulation fan and operating the air circulation fan at the first speed and a heating unit in a first configuration with at least one active burner from a plurality of burners where less than all of the burners are active when the heating unit is in the first configuration. The method further includes measuring a first temperature while operating the air circulation fan at the first speed, determining a temperature difference between the first temperature and the temperature set point, comparing the temperature difference to a temperature difference threshold, and updating the temperature map to map the first speed to the first temperature when the temperature difference is greater than the temperature difference threshold.

A recirculation pump system provides the ability to recirculate water from a water heater outlet, back into a water heater inlet through a cold-water supply line. The recirculation pump system pumps heated water, which may have cooled to a sub-optimal temperature, into a water heater. The recirculation pump system provides the ability to use a plumbing network that does not contain a dedicated recirculation line. The recirculation pump system uses a water pump to circulate water, a temperature sensor to control system activation based on water temperature, and a check valve to control the direction of fluid flow. This recirculation pump system provides a minimally invasive way to install a recirculation system into a plumbing network that otherwise would not be able to accommodate recirculation functions, and service modern plumbing fixtures efficiently.

A hot water supply system decouples an intelligent hot water storage system from a water heating engine system. The water heating engine system includes a plurality of instantaneous water heaters that provide for redundant operation for improved reliability. The intelligent hot water storage system includes a storage tank that encloses a volume for storage of water. The intelligent hot water storage system includes a recirculation loop driven by an integrated pump and operated by an integrated controller. By positioning the tank recirculation outlet and inlet farther apart from each other, additional usable volume of hot water is provided by the intelligent hot water storage system. Isolation valves positioned on the input and output of a recirculation pump in the recirculation loop facilitate repair or replacement of the recirculation pump. The hot water system provides for increased capacity while providing redundant heating engines in a smaller floor space than conventional systems.

As a circulation pump is activated while a hot water supply faucet is closed, an immediate hot water supply circulation path is formed to bypass the hot water supply faucet on the outside of a water heating apparatus and to pass through a heat exchanger in the inside of the water heating apparatus. A controller determines in a test mode, whether or not the immediate hot water supply circulation path has been formed by connection of a thermal water stop bypass valve, based on whether or not a temperature detector senses increase in temperature to a predetermined criterion temperature while the circulation pump and a heat source apparatus are active.