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 leak detection system. The leak detection system includes a leak sensor assembly that is disposed in a bottom pan of the water heater. The leak sensor assembly includes a sensor housing that has a sensor channel that is formed therein such that the sensor channel is disposed at an elevation from a base of the bottom pan when the sensor housing is disposed on the base of the bottom pan. Further, the leak sensor assembly includes a leak sensor that is disposed in the sensor channel of the sensor housing. The leak sensor detects water that leaks from the water heater and accumulates in the bottom pan when a level of the water in the bottom pan rises to the elevation of the sensor channel and the leak sensor that is disposed therein.

A switch assembly includes an automatic type 11 switch having 1 and 2 contacts and 3 and 4 contacts with the 2 and 3 contacts being shorted together, configured to respond to a water level of a boiler, short the 1 and 2 contacts when the water level is high, short the 3 and 4 contacts when the water level is low; and an electronic circuit board having a processor configured to sense signaling containing information about the 1, 2/3 and 4 contacts, and provide control signaling containing information about the water level of the boiler. The electronic circuit board also includes a relay configured to respond to the control signaling, and turn the relay on/off.

A method, system or computer usable program product for controlling an on-demand hot water heater including providing a plurality of nodes for receiving hot water from an on-demand hot water heater in a hot water delivery system, receiving a demand with a node identifier for hot water at a node, determining a hot water temperature for the node from a centralized database, the database including a set of node identifiers with a corresponding set of preset hot water temperatures, and controlling a temperature of hot water flowing from the water heater based on the determined hot water temperature.

In one aspect, a first device includes a processor and storage accessible to the processor. The storage bears instructions executable by the processor to receive input from a water heater meter that monitors a water heater and provide an output comprising information pertaining to a time estimate related to the provisioning of heated water based on the input.

Provided is a method for controlling a cascade boiler system, and the method includes a) operating the number of boilers set in an initial operation state, b) detecting a supply water temperature and a returned water temperature of the primary side of the hydro-separator and a supply water temperature and a returned water temperature of the secondary side, and calculating a flow rate corrected by the hydro-separator using the detected temperatures, c) calculating a set temperature serving as the supply water temperature of the primary side that is able to maintain the supply water temperature of the secondary side when the supply water temperature of the secondary side is within a set range of a target temperature while maintaining the initial operation state, and d) calculating the number of boilers that are able to maintain the calculated set temperature, and controlling an operation of the boilers according to the number.

An air-conditioning and hot water supplying composite system includes a heat source unit and a heat source-side heat exchanger, an indoor heat source unit, a hot water supply unit connected to the heat source unit and including a hot water supply-side heat exchanger and a hot water supply-side expansion device, and a controller that controls the heat source unit. The controller includes a mode switching unit that switches a control mode of the air-conditioning and hot water supplying composite system between a hot water supply control mode, a hot water supply preheating mode, and a condensing temperature control unit. The condensing temperature control unit determines the target condensing temperature according to a temperature of a heat medium subjected to heat exchange by the hot water supply unit, in the hot water supply control mode.

A boiler unit (100) housed in an enclosure, the boiler unit (100) configured to receive a solid state combined heat and power generating device (130). The boiler unit (100) comprises a heating device (110) to produce heat; and a control unit (120) to independently control each of the heating device (110) and the solid state combined heat and power generating device (130). The boiler unit (100) is operable without the solid state combined heat and power generating device (130) being present.

The present invention provides a hot water supply device. When a hot water supply operation is started in response to an instruction for checking a heat exchange state, a heat exchange state determiner 12 measures a post-boiling temperature Tup, which indicates the rise width of a temperature detected by a heat exchange outlet temperature sensor 26 from the point when the hot water supply operation stopped, and outputs a heat exchange success report if the post-boiling temperature Tup is lower than a first threshold temperature. Further, when the hot water supply operation is started independently of the instruction for checking a heat exchange state, the heat exchange state determiner 12 outputs a report of clogging of a heat exchanger if the post-boiling temperature Tup is higher than a second threshold temperature Bth, which is higher than the first threshold temperature Ath.

Feedwater to be supplied to a feedwater tank via a feedwater path is passed through a waste heat recovery heat exchanger, a supercooler, and a condenser in sequence. A heat source fluid such as heat source water is passed through an evaporator and the waste heat recovery heat exchanger in sequence. The waste heat recovery heat exchanger is an indirect heat exchanger between the feedwater supplied to the feedwater tank via the feedwater path and the heat source fluid having passed through the evaporator. The supercooler is an indirect heat exchanger between the feedwater supplied to the feedwater tank via the feedwater path and a refrigerant supplied from the condenser to an expansion valve.