A device for a sanitary facility, intended for rapidly delivering Domestic Hot Water (DHW) to the supply points without wasting energy. The device according to the invention transfers the DHW rapidly from the source to the user as soon as there is a need for it. The method, which prevents any recirculation, makes it possible, in particular, to save the large amount of energy that is systematically wasted each time the DHW is distributed between its source and the supply points. The device essentially consists of a motorised, relatively powerful pump (2) which channels the DHW from the source (1) and injects it into a pipe with a very small cross-section (3) that conveys the entire flow rate required by the user at a high velocity to the supply point (41). An adapted sensor (5) controls the switching on and off of the motor pump (2) upon each use and controls its flow rate on the basis of the requirements. A single device can be used for supplying multiple supply points. It can be fitted to all new or existing facilities.

A circulating hot water system has a hot water flow circuit defined by pipework leading out from and back to an in-line heater, and including a pump to drive circulation of the hot water. Each of multiple user points has an outflow branch conduit and a return flow branch conduit with a common wall for heat exchange, as does the main flow circuit: the outflow conduit surrounds the return conduit. Water is fed into the system from a pressurized cold water supply main through a check valve. Sensors are used to monitor water temperatures and flow conditions around the system. A programmed control processor can control heating and pumping rates in various regimes, e.g. to maintain system temperature above a predetermined threshold. An isolation valve adapted for concentric double pipes is also described.

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.

A device for a sanitary facility, intended for rapidly delivering Domestic Hot Water (DHW) to the supply points without wasting energy. The device according to the invention transfers the DHW rapidly from the source to the user as soon as there is a need for it. The method, which prevents any recirculation, makes it possible, in particular, to save the large amount of energy that is systematically wasted each time the DHW is distributed between its source and the supply points. The device essentially consists of a motorised, relatively powerful pump (2) which channels the DHW from the source (1) and injects it into a pipe with a very small cross-section (3) that conveys the entire flow rate required by the user at a high velocity to the supply point (41). An adapted sensor (5) controls the switching on and off of the motor pump (2) upon each use and controls its flow rate on the basis of the requirements. A single device can be used for supplying multiple supply points. It can be fitted to all new or existing facilities.

The concepts relate to reducing energy loss associated with hot water systems. One example can monitor hot water use in a system. Upon completion of the hot water use, the example can recover some of the hot water from hot water lines into a water heater that heated the hot water. The method can also deliver the recovered hot water to the water heater in a manner that affects operation of a heating element of the water heater.

The concepts relate to reducing energy loss associated with hot water systems. One example can monitor hot water use in a system. Upon completion of the hot water use, the example can recover some of the hot water from hot water lines into a water heater that heated the hot water. The method can also deliver the recovered hot water to the water heater in a manner that affects operation of a heating element of the water heater.

A circulating hot water system has a hot water flow circuit defined by pipework leading out from and back to an in-line heater, and including a pump to drive circulation of the hot water. Each of multiple user points has an outflow branch conduit and a return flow branch conduit with a common wall for heat exchange, as does the main flow circuit: the outflow conduit surrounds the return conduit. Water is fed into the system from a pressurized cold water supply main through a check valve. Sensors are used to monitor water temperatures and flow conditions around the system. A programmed control processor can control heating and pumping rates in various regimes, e.g. to maintain system temperature above a predetermined threshold. An isolation valve adapted for concentric double pipes is also described.

A recirculation valve according to the present invention comprises: a warm-water housing communicating with a warm-water supply tube for supplying warm water generated by heating raw water, thereby forming a warm-water channel provided such that warm water flows through the inside thereof; a direct-water housing communicating with a direct-water supply tube through which direct water (raw water) is supplied, thereby forming a direct-water channel provided such that direct water flows through the inside thereof; a recirculation housing through which the warm-water channel and the direct-water channel communicate with each other, thereby forming a recirculation channel provided such that warm water in the warm-water channel flows to the direct-water channel; and a water-pressure opening/closing body provided inside the direct-water housing to be able to move according to a reference direction in order to close or open the recirculation channel. The water-pressure opening/closing body comprises an upstream pressurizing unit and assuming that the direction in which direct water flows into the direct-water channel from the direct-water supply tube is a reference direction, a downstream pressurizing unit positioned in the reference direction from the upstream pressurizing unit. The inner surface of the direct-water housing, which defines the direct-water channel, comprises an upstream inner surface positioned on the outside of the upstream pressurizing unit when the water-pressure opening/closing body is positioned to open the recirculation channel, and a downstream inner surface positioned in the reference direction from the upstream inner surface. A stepped portion is formed between the upstream inner surface and the downstream inner surface so as to correspond to a stepped portion formed between the upstream pressurizing unit and the downstream pressurizing unit.