A system for regulating a thermo-hydraulic circuit has a thermal machine, a heat exchange terminal, a carrier fluid circulation system having a delivery duct, a return duct, and a three-way valve. The system has a pump, a first temperature sensor measuring post-valve delivery temperature of the carrier fluid downstream of the three-way valve, a second temperature sensor measuring pre-valve delivery temperature of the carrier fluid, and a third temperature sensor measuring temperature of the carrier fluid downstream of the heat exchange terminal. A flow or flow rate sensor measures a mass or volumetric flow rate of the carrier fluid. An electronic control unit has a storage device in which a model function of the thermo-hydraulic circuit is stored. A processing unit calculates values of a valve control signal and a pump control signal as function of a mass or volumetric flow rate error and a carrier fluid delivery temperature error.

The present disclosure provides for a recirculating flow controller that is operably coupled to a flow switch and to a recirculation pump. The recirculating flow controller determines that hot water has begun to flow by way of the connection with the flow switch. In response, the recirculating flow controller activates the recirculation pump to circulate hot water from a water heater. The recirculating flow controller can activate the recirculation pump for a predetermined duration. The flow switch can be configured to sense flow in a hot water line connected to a water heater. The flow switch can be activated by turning on any hot water faucet connected to the water heater.

A tankless water heater (TWH) isolation valve includes a valve body having a plug valve port, a TWH port, a water distribution system port and a drain port. A plug valve includes at least one plug seal. The plug valve is controlled by a rotatable plug valve handle. The plug valve is disposed through the plug valve port and within the valve body. The rotatable plug valve handle includes a first plug valve handle position and a different rotated second plug valve handle position. In a normal operating mode in the first plug valve handle position, the TWH port is fluidly coupled to both of the drain port and the water system distribution port. In a drain mode, the TWH port is fluidly coupled to the drain port, and the water system distribution port is closed to the TWH port as blocked by the plug seal.

An instant hot water dispenser system includes a main body, having a water flow control valve seat, a water inlet and a water outlet, the water flow control valve seat being provided with a first flow control valve and a second flow control valve; a faucet being provided with a first pull member, a second pull member and a water outlet pipe; a first heating unit having a first water storage space and a heater; a second heating unit having a circulating water path and an instantaneous heater, the instantaneous heater being configured to instantaneously heat a water supply in the circulating water path to a predetermined temperature; a processing unit electrically connected to a control interface, the processing unit being further electrically connected to the water flow control valve seat, the first heating unit and the second heating unit.

An isolation valve assembly comprises a valve body defining a first fluid port and a second fluid port opposing the first fluid port and at least one drain port disposed between the first fluid port and the second fluid port, an isolation valve disposed within the valve body and a handle operatively coupled to the isolation valve. The handle is movable to cause corresponding movement of the isolation valve between a first normal position where the isolation valve fluidly couples the first fluid port and the second fluid port, and a second drain position where the isolation valve fluidly couples the first fluid port and the at least one drain port and isolates the second fluid port.

A hot water supply device including an inlet pipe, an outlet pipe, a burner unit, a heat exchanger, an exhaust aperture, a first temperature sensor detecting a measured exhaust temperature of the exhaust gas, a second temperature sensor detecting a water temperature of water entering the inlet pipe, and a processor. The processor is configured to obtain an error between the measured exhaust temperature and an estimated exhaust temperature, and detects that scale clogging has occurred inside the heat exchange tubing based on an index which is generated using the error between the measured exhaust temperature and the estimated exhaust temperature. The estimated exhaust temperature is a first predetermined value that is determined using a numerical equation which has at least the water temperature of water entering the inlet pipe and a scale number of the hot water supply device as variables of the numerical equation.

Provided are a boiler and a method for stage change control of the boiler. The boiler includes a burner to generate a calorie necessary for producing hot water by burning air and gas, and a controller to perform a stage change control operation, when the number of times, in which the stage is changed, is equal to or greater than a reference number of times, for a predetermined time, based on information on occurrence of the change of the stage in the burner, while hot water is used.

A water heater includes a first heater, a second heater, and a controller. The controller can enable different operational modes of the water heater, wherein only the first heater operates, only the second heater operates, or both the first and the second heaters operate. The controller can also be configured to enable a hybrid operational mode and a bypass operational mode. Further, in the different operational modes, the controller can direct water flow to at least one of a first conduit coupled to the first heater, a second conduit coupled to the second heater, and a bypass conduit. The controller can be configured to receive input signals relating to environmental conditions around the water heater and/or an aquatic system in which the water heater is installed.

A hot water supply apparatus of the present invention includes: a direct water inlet pipe into which direct water is introduced; a heat exchanger for heating direct water introduced through the direct water inlet pipe with combustion heat of a burner; a hot water supply pipe for discharging the hot water heated in the heat exchanger; a bypass pipe connected between the direct water inlet pipe and the hot water supply pipe so as to mix a part of the direct water introduced through the direct water inlet pipe with the hot water discharged through the hot water supply pipe; and a pressure reducing valve provided on the bypass pipe and configured to reduce the pressure of water passing through the inside of the bypass pipe to supply the water to the hot water supply pipe when hot water is supplied.

A water heating system can include a water heater having a tank, an inlet line, and an outlet line, where the inlet line provides unheated water to the tank, and where the outlet line draws heated water from the tank. The water heating system can also include multiple sensing devices, where each sensing device of the plurality of sensing devices measures a parameter associated with the tank. The water heating system can further include a controller communicably coupled to the plurality of sensing devices, where the controller determines an amount of heated water in the tank based on measurements made by the plurality of sensing devices.