A water heater system includes a controller configured to integrate control of both recovery and recirculation operations of a recovery pump and a recirculation pump. As such, a separate device, installation location, and power source (e.g., available outlet) is not needed with the controller. Because a single controller is configured to control both recovery and recirculation operations, additional control functions are available. The controller may be in communication with an internal controller of the water heater and configured to receive an error notification upon abnormal operation of the water heater. The controller can stop recovery and recirculation operations in response to an error notification, unlike with traditional water heating systems which may otherwise continue to function. The recovery and recirculation operations are based on a setpoint temperature of the water heater such that changes made to the setpoint temperature will automatically adjust in the recovery and recirculation operations.

A water heater monitoring and notification method includes determining, by a controller of a water heater system, a deviation of a duration of a pre-purge operation from a pre-purge duration average value. The method further includes determining, by the controller of the water heater system, a deviation of a flame current from a flame current average value and determining, by the controller of the water heater system, a deviation of a pulse-width-modulation (PWM) parameter from a PWM parameter average value. The method also includes providing a notification related to a combustion system of the water heater system based on at least the deviation of the duration of the pre-purge operation from the pre-purge duration average value, the deviation of the flame current from the flame current average value, and the deviation of the PWM parameter from the PWM parameter average value.

A method of heating water in a water storage tank. The method includes: selecting an outlet port and an inlet port from at least three ports located in the tank at different heights along a vertical direction. The outlet port is below the inlet port. The method further includes extracting water from the outlet port, supplying the extracted water to an external heat exchanger configured for heating the extracted water, and delivering heated water from the heat exchanger to the selected inlet port.

A water heater includes a water tank having an inlet and an outlet, and a flue extending through the tank. A nozzle is positioned near a first end of the flue, arranged so as to emit a fuel stream into the flue, and a flame holder is located within the flue in a position to receive the fuel stream and to hold a flame entirely within the flue. A controller variably controls a flow of fuel to the nozzle according to a temperature of water in the tank.

An electric water heater having a water holding tank defined by a cylindrical side wall, a top wall and a dome-shaped bottom wall. A cold water inlet is disposed for releasing water under pressure in a lower portion of the tank. Two or more resistive heating elements heat water in an upper and lower region of the tank. The lower portion of the cylindrical side wall and the outer circumferential portion of the dome-shape bottom wall form a circumferential cavitated area inside the tank in which sediments deposit forming a bed in which bacteria can proliferate. A conduit is secured about at least a substantial circumferential portion of an outer surface of the cylindrical side wall adjacent the cavitated area. A resistive heating wire is disposed in the conduit and has connection leads extending out of a free open end of the conduit to an access area to provide connection to power terminals and a control for controlling the supply of power to the resistive heating wire.

A hot-water supply system heats up water by power generated by power generation means. The hot water supply system includes a compressor and a water heat-up unit. In the hot-water supply system, the compressor compresses refrigerant and circulates the refrigerant through a refrigerant circuit. The water heat-up unit heats up water by changing, in accordance with the generated power, a rotation rate of an electric motor for driving the compressor.

A hot water unit fluid supply control system for a hot water unit is disclosed. The hot water unit has a heating system that is operable in a heating cycle to heat up water in at least a first region of the water unit, and a sensor arrangement for sensing a temperature of water of the hot water unit. The control system comprises a control unit configured to: receive operational data relating to an operation of the heating system; receive temperature data from the sensor arrangement; and allow for a volume of water from the first region to be released from the hot water unit as treated water or usable water based on: the operational data, and the temperature data from the sensor arrangement.

A water heater monitoring and notification method includes determining that an intake pressure switch of a combustion system of a water heater or an exhaust pressure switch of the combustion system of the water heater is open and shutting down a blower of the combustion system in response to the intake pressure switch or the exhaust pressure switch being open.

An electric water heater is described and wherein the bottom portion of the water holding tank is provided with various forms of electric heating elements to heat the water in the lowermost region of the tank adjacent the dome-shaped bottom wall to a temperature sufficient to prevent the proliferation of bacteria growth such as the Legionella bacteria in such lowermost region. The insulating foam support base of the water heater also provides a thermal barrier to the heating elements while biasing the heating element on the dome-shaped bottom wall in a region to insure excellent heat transfer to the cavitated zone surrounding the dome-shaped bottom wall where sedimentary deposits occur to create a culture medium for bacteria growth.

The present invention improves the user-friendliness of a hot-water supply apparatus when using hot water supply and air conditioning. A switching control unit 27, which switches between heat medium flow paths 4 and 5 according to an air conditioning ready state or a hot-water supply ready state, switches a heat medium flow path to the hot-water supply ready state by a switching valve 21 in the case where air conditioning is not used by the time an air conditioning standby time elapses during standby in the air conditioning ready state.