BACKGROUND TO THE INVENTION

This invention relates to a water management or water saving system. In particular, but not exclusively, the invention relates to a water saving system configured to prevent wastage of suboptimal temperature water from a hot water supply.

Water is an essential resource, yet globally more than 2.1 billion people live without access to safe drinking water in their homes, with 844 million people having no access to safe drinking water at all. Clean or potable water needs to be used responsibly, especially in semi-arid and arid countries where water is sparse.

A substantial contributor to water wastage is the wastage experienced in hot water systems. Hot water systems typically include a hot water source which is in flow communication with a hot water outlet, such as a shower head, via a conduit. When the hot water system is not in use, the water in the conduit cools down to a suboptimal temperature. When hot water is required, the suboptimal temperature water in the conduit is first expelled from the conduit before water at an optimal temperature reaches the hot water outlet. Depending on the distance between the hot water source and the hot water outlet, it can typically take between 15 seconds and 120 seconds before the water at the outlet is deemed optimal in temperature. This typically translates to the loss of between 4 and 24 litres of clean water.

It is possible to reroute the wasted water to water storage or to simply fill a container with the suboptimal temperature water. However, these methods of preventing the wastage of water either require structural changes, or require a user to physically make an effort to collect the water.

Water saving systems also exist in which the suboptimal temperature water is first stored in a localised reservoir before being mixed in with the hot water when it is deemed to be at its optimal temperature. These systems are effective but have limited application due to the size and capacity of the reservoir required to store the suboptimal temperature water. In particular, showers have limited space for retrofitting such a device to the existing taps and outlet.

Ring feed systems are also known for reducing the wastage of water in hot water systems. A ring feed system includes a centralised hot water source such as a geyser or boiler from which hot water is circulated through a conduit. The premise of such a system is that the distance between hot water outlet and the hot water source is substantially reduced. Instead of waiting for the hot water to travel from the hot water source to the hot water outlet, hot water is fed to the hot water outlet from the circulating ring which is much closer in proximity with the outlet than the hot water source. However, the main problem with a ring feed system is the difficulty of implementing such a system in an already existing hot water system. A ring feed system is therefore only practically applicable in new developments where the infrastructure for the system can be properly installed. A ring feed system also results in the loss of energy due to heat loss through the conduit where hot water is continuously circulated.

It is an object of this invention to alleviate at least some of the problems experienced with existing methods of saving water in hot water systems.

It is a further object of this invention to provide a water saving system that will be a useful alternative to existing water saving systems for use in hot water applications.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention, there is provided a water saving system, comprising: a hot water inlet, in use provided in flow communication with an upstream hot water source; a cold water inlet, in use provided in flow communication with an upstream cold water source; an outlet for directing water, in use, to a user; a first valve arrangement located upstream of the outlet, wherein the first valve arrangement is, in use, actuatable between a closed configuration and an open configuration; a temperature sensing means located proximate the hot water inlet for, in use, sensing a temperature of water downstream of the hot water inlet; a circulation passage providing flow communication between the hot water inlet and the cold water inlet; a pump having a pump inlet, which, in use, is in flow communication with the hot water inlet; a second valve arrangement located in the circulation passage, wherein the second valve arrangement is, in use, actuatable between an open configuration and a closed configuration; and a control system for receiving input from the temperature sensing means and for producing an output derived from the input received from the temperature sensing means, wherein, in use, the system is configurable between an inoperative mode, wherein the first valve arrangement is in the closed configuration; a circulating mode, wherein the first valve arrangement is in the closed configuration, the second valve arrangement is in the open configuration and the pump is configured to pump water from the hot water inlet such that water is pumped to the cold water inlet via the circulation passage; and an operative mode, wherein the second valve is in the closed configuration and the first valve is in the open configuration allowing water from at least one of the hot water inlet; the cold water inlet; and both the hot water inlet and cold water inlet, to flow through the outlet.

The system may furthermore comprise mixing means in flow communication with the hot water inlet and the cold water inlet. The mixing means may be configured, in use, to mix water from the hot water inlet and water from the cold water inlet. The mixing means may comprise an automatic mixing valve in the form of one of a thermostatic mixing valve and an electronically controlled mixing valve.

The first and second valves may comprise a first and second electronically controlled valve respectively.

The output produced by the control system relates to the mode in which the system is to be configured. The control system may be configured to control the first and second electronically controlled valves and the pump, based on the output produced by the control system. The control system may therefore be configured to configure the system into one of the modes or between modes.

In use, the cold water source has a pressure of between 0.5 and 6 bar, and wherein the pump is configured to pump water from the hot water inlet to the cold water inlet via the circulation passage at a pressure above a pressure differential between the cold water source and the hot water source, when the system is configured in the circulating mode.

When the system is configured in the circulating mode, the pump may have a flow rate of between 3001/hour and 20001/hour, and preferably, about 14001/hour.

The pump may comprise a centrifugal pump or a positive displacement pump.

The second valve arrangement may include a non-return valve (in addition to the electronically controlled valve). The non-return valve may be located in the circulation passage and operatively downstream of the pump and may be arranged to inhibit water from flowing through the circulation passage from the cold water inlet to the hot water inlet, in use.

Non-return valves may furthermore be located between the hot water inlet and the mixing means, such that water is inhibited from flowing from the mixing means to the hot water inlet, in use, and between the cold water inlet and the mixing means, such that water is inhibited from flowing from the mixing means to the cold water inlet, in use.

The system may furthermore comprise a safety temperature sensing means in communication with the control system, which may be and located towards the outlet. The safety temperature sensing means may be configured, in use, to measure the temperature of the water at the outlet and provide an input to the control system. The control system may use the input received from the safety temperature sensing means when producing the output. Alternatively, the temperature sensing means may simultaneously act as a safety temperature sensing means.

The system may further comprise a flow control means, such as a flow control valve, located upstream of the outlet. The flow control means may be used to vary the pressure or flow rate of the water flowing out of the outlet, when the system is configured in the operative mode.

The control system may include a display for operatively displaying at least one of: i) a temperature of the water flowing at the hot water inlet; ii) a temperature of the water at the outlet; iii) a mode of operation of the system; iv) a duration of the operation of the system in the operative mode; and v) a warning of the imminent termination of the operation of the system.

The system may include a start switch and/or a pause switch and/or a stop switch, with which commands may be communicated to the control system.

The hot water source may take the form of a geyser or a boiler or a combination of a boiler and a gravity fed system, while the cold water source may take the form of a mains water supply.

In accordance with a second aspect of the invention, there is provided a method of saving water using a water saving system according to the first aspect of the invention, the method including the steps of: providing the water saving system in an inoperative mode, wherein the first valve and the second valve are closed; configuring the system into a circulating mode, by opening the second valve and activating the pump while retaining the first valve in the closed configuration, thereby causing water to be pumped from the hot water inlet to the cold water inlet, via the circulation passage; and configuring the system in an operative mode, by closing the second valve and opening the first valve.

There is provided for the method to comprise the step of continuously measuring the temperature of the water at the hot water inlet.

The system may be configured to remain in the circulating mode until the measured water temperature reaches a predetermined optimal water temperature. There is provided for the system to be configured in the operative mode when or after the temperature of water at the hot water inlet reaches the predetermined optimal temperature.

There is provided for the pump to be activated when the system is configured in the operative mode, to increase the pressure or flow rate of water flowing through the outlet.

A user may be alerted when the water is at the optimal temperature.

In accordance with a third aspect of the invention, there is provided a plumbing arrangement of a building, the plumbing arrangement comprising a cold water source; a hot water source and a water saving system in accordance with a first aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a water saving system in accordance with a first embodiment of the invention;

Figure 2 shows a schematic diagram of the water saving system of Figure 1 ;

Figure 3 shows a water saving system in accordance with a second and preferable embodiment of the invention;

Figure 4 shows a water saving system in accordance with a third embodiment of the invention; and Figure 5 shows a plumbing installation at a house, illustrating tie-in points of the water saving system in accordance with the invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings and are thus intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings. Additionally, the words "lower", "upper", "upward", "down" and "downward" designate directions in the drawings to which reference is made. The terminology includes the words specifically mentioned above, derivatives thereof, and words or similar import. It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

Referring to the drawings, in which like numerals indicate like features, a non limiting example of a water saving system in accordance with the invention is generally indicated by reference numeral 10. As will be appreciated from the figures and the description which follows, the system 10 may take various forms, of which only a selected number of embodiments will be discussed.

With reference to figures 1 and 2, the water saving system 10 according to a first example embodiment includes a hot water inlet 12 in flow communication with a hot water source 102 (shown in figure 5) such as a boiler, geyser or combination of a boiler and gravity fed system (which is situated upstream of the hot water inlet 12, such that water is, in use, supplied from the hot water source 102 to the system 10, through the hot water inlet 12). The system 10 further includes a cold water inlet 14 in flow communication with a cold water source 104 (which cold water source 104 is situated upstream of the cold water inlet 14, such that water is, in use, supplied from the cold water source 104 to the system 10, through the cold water inlet 14), in particular in the form of a water mains. The system 10 also includes an outlet 16 which is typically in flow communication with a shower head or other hot water outlet.

As shown in figure 5, the hot water source 102 typically forms part of a plumbing arrangement 100 of a typical building, such as a house. Typically, a non-return valve 106 is provided as part of the plumbing arrangement 100, to inhibit water from the plumbing arrangement 100 from flowing into the cold water source 104 (water mains).

The system 10 includes mixing means 18 or a mixing valve. The mixing means 18 is in flow communication with the hot water inlet 12 and with the cold water inlet 14. In use, water entering the mixing means 18 from the hot water inlet 12 and the cold water inlet 14 is combined, mixed and directed to the outlet 16. A first valve arrangement 20 is located at the outlet 16. The first valve arrangement 20 is preferably in the form of an electronically controlled valve 20. The first electronically controlled valve 20 is actuatable between a closed position or configuration and an open position or configuration, depending on an operation mode of the system 10. More about this is said below.

A variable flow control valve 22, seen in Figure 2, is also located at the outlet 16. However, this is not essential to the working of the invention. The variable flow control valve 22 allows a user, in use, to restrict the water flow from the outlet 16 which further limits water consumption . Typically, the mixing means takes the form of an automatic or automated mixing valve. In the first illustrated embodiment of the invention the mixing means 18 is in the form of a thermostatic mixing valve or an electronically controlled mixing valve. This allows a user to set a maximum, desired or required temperature of the water exiting the mixing means 18. A safety temperature sensing means 24, seen in Figure 2, is located upstream of the first valve arrangement 20. The safety temperature sensing means 24 is configured to measure the temperature of the water flowing towards the outlet 16. More about this is said below.

In the first embodiment, it is envisaged that a non-return valve 26 (shown in figure 2) may be located between the mixing means 18 and the hot water inlet 12. Similarly, it is envisaged that a non-return valve 28 may be located between the mixing means 18 and the cold water inlet 14. These non-return valves prevent or inhibit backflow of water from the mixing means 18 back to the hot water inlet 12 and the cold water inlet 14 respectively.

The system 10 further includes a circulation or flow passage 30 providing flow communication between the hot water inlet 12 and the cold water inlet 14. A pump 32 is located in the flow passage 30 and is configured, in use, to pump water via the flow passage 30 from the hot water inlet 12 to the cold water inlet 14 (by increasing the pressure of the water from the hot water inlet). An inlet of the pump 32 is provided in flow communication with the hot water inlet 12. The pump 32 is configured such that it produces a pressure higher than a pressure differential between the hot and cold water inlets. The cold water source is typically between 0.5 and 6 bar, depending on a pressure regulator installed in a household, for example. In the illustrated embodiment, the pump 32 provides a flow rate of between 3001/hour and 20001/hour, preferably 14001/hour. The pump 32 may be a centrifugal pump or a positive displacement pump but it is envisaged that any suitable pump may be used for the purposes of the invention. A non-return valve 34 (shown in figure 2) is located in the flow passage 30, which non-return valve 34 is configured to inhibit or prevent water from the cold water inlet 14 from flowing towards the hot water inlet 12 through the pump 32. This is included for cases where the cold water source 104 has a higher pressure than the hot water source 102. A second electronically controlled valve 36 is also located in the flow passage 30. The second electronically controlled valve 36 is actuatable between a closed configuration and an open configuration depending on the operation mode of the system 10. More about this is said below.

The system 10 also includes temperature sensing means in the form of a temperature sensor 38, which, in the embodiment shown in figures 1 and 2, is located at the hot water inlet 12. The temperature sensor 38 is configured to measure the water temperature entering the system 10 at the hot water inlet 12. The temperature sensor 38 communicates with a central control system 40. The control system 40 therefore receives measurements from the temperature sensor 38 as an input, and produces an output based thereon. The output produced by the control system 40 relates to the mode in which the system 10 is to be configured. In the present example embodiment, the control system determines the mode in which the system is to be configured based on the input received from the temperature sensor 38, and determines and controls the positions or configurations of the first electronically controlled valve 20 and the second electronically controlled valve 36, the operation of the pump 32 and the operation of the mixing means 18 accordingly.

The control system 40 includes a display (not shown) for displaying one of or a combination of: the temperature of the water flowing from the mixing means 18, the temperature of the water at the outlet 16, the mode of operation of the system 10, the duration of the operation of the system in the operative mode and any warnings relating to the imminent termination of the operation of the system 10. The control system 40 also includes a start switch 42, for activating the system and a stop switch 44, for stopping the functioning of the system 10. The control system also includes a pause switch 46 which pauses the operation of the system 10. It is envisaged that the pause switch 46 only functions when the system 10 is operating. The control system 40 also includes an alarm (not shown) for alerting the user during use. In the description of the functioning of the system 10 below, the use of the control system 40 will become more clear.

The system 10 also includes a power source 48. The power source 48 may be in the form of the main power supply or a self-contained battery. Where a battery is implemented, the control system 40 will include a charge controller. The power source 48 provides the necessary power to the control system 40, first electronically controlled valve 20, the second electronically controlled valve 36 and the temperature sensor 38.

The functioning of the system 10 will now be described in more detail. The system 10 is configured to operate in separate or different operation modes, namely an inoperative mode, a circulating mode and an operative mode. In the inoperative mode, the system 10 is inoperative and the first electronically controlled valve 20 is in the closed position or configuration. In this mode, no water flows through the system 10 or out of the outlet 16. Therefore, typically, the pump 32 will not be operational and the second valve arrangement 36 will be closed.

In use, the mixing means 18 in the form of the thermostatic control valve is set to the desired temperature by a user. The start switch 42 is then actuated on the control system 40 which activates the system 10 and initiates the circulating mode.

In the circulating mode, the second electronically controlled valve 36 is actuated into its open position or configuration and the pump 32 is switched on. This allows water from the hot water inlet 12 to be pumped via the flow passage 30 to the cold water inlet 14. The pressure differential between the cold water source and the pressure provided by the pump 32 allows the water from the hot water inlet 12 to be pumped toward the cold water source. This allows the water to be circulated via the cold water inlet back to the hot water source (as will be appreciated from figure 5). It is important to note that the hot water source is also in flow communication with the cold water source. For example, a geyser, is in flow communication with the same cold water source as the cold water inlet. This facilitates the circulation of the water. The non-return valve 106 inhibits the water circulated by the system 10 from flowing into the water mains, and therefore facilitates the circulated water to flow back into the hot water source 102. The system 10 will remain in the circulating mode as long as the temperature measured by the temperature sensor 38 is at a sub-optimal temperature. During the circulating mode, the first electronically controlled valve 20 remains in its closed position or configuration. Alternatively, a user may override the circulating mode and manually actuate the operative mode of the system 10. This may be achieved by holding the start switch 42 or by way of a similar action. In many cases, for example where there has been a power outage and the hot water source is unable to reach the optimal temperature, the user is able to override the circulating mode.

Once the temperature sensor 38 detects that the water entering the system at the hot water inlet 12 is at an optimal temperature, the control system 40 switches off the pump 32, actuates the second electronically controlled valve 36 into its closed position or configuration and actuates the first electronically controlled valve 20 into its open position or configuration, or alerts the user, to enable the user to cause the first valve 20 to be actuated to the open position or configuration. Once the first valve 20 is in the open position or configuration, the system 10 is in the operative mode. In an alternative embodiment, it is envisaged that once the temperature sensor 38 detects that the water entering the system at the hot water inlet 12 is at an optimal temperature, the control system 40 switches off the pump 32 and actuates the second electronically controlled valve 36 into its closed position or configuration and alerts the user that the optimal temperature of the water has been reached. The user may then manually actuate the system 10 into its operative mode.

In the operative mode, water from the hot water inlet 12 is directed to the mixing means 18. Similarly, water from the cold water inlet 14 is directed to the mixing means 18. The hot water from the hot water inlet 12 mixes with the cold water from the cold water inlet 14 in the mixing means 18 and is directed to the outlet 16. The pressure of the water flowing from the outlet 16 may be varied by the flow control valve 22 by the user.

In the first illustrated embodiment, the safety temperature sensing means 24 continuously measures the temperature of the water at the outlet 16. In the case that the temperature exceeds a predetermined temperature deemed to be dangerously hot and which could scald the user, the operation of the system 10 will be automatically terminated. It is also envisaged that the operative mode may either be terminated or paused after a predetermined time of operation, for example 3 minutes. The alarm may alert the user when the predetermined time is almost over. Alternatively, the user may terminate the operative mode of the system 10 at any point by actuating the stop switch 44. Once the operative mode is terminated, the system 10 is actuated into the inoperative mode and the first electronically controlled valve 20 is actuated into the closed position or configuration. When the system 10 needs to be used again, the method as set out above is simply repeated.

It is envisaged that the user may at any point during the operation of the system 10 in the operative mode, pause the operation of the system 10 by actuating a pause switch on the control system 40. By actuating this switch the first electronically controlled valve 20 is actuated into the closed position or configuration. It is also envisaged that any timing indicated on the control system will also automatically pause. When the start/play switch is then actuated, the operative mode of the system 10 recommences and the first electronically controlled valve 20 actuates back into its open position or configuration. When the system 10 is paused for longer than a predetermined time, for example 30 seconds, or if the user actuates a stop switch, the system 10 is actuated into the inoperative mode.

The system 10 is preferably housed within an enclosure (not shown). The enclosure is mounted to a structure, in particular a wall, by way of mounting means 50.1 , 50.2. The mounting means 50.1 , 50.2 may be in any suitable form, for example by way of anchor bolts or expansion bolts. The enclosure contains all of the components of the system 10 and may be made of a plastic or stainless steel. The enclosure must also be water resistant so that no water may reach the electronic components. It is envisaged that the system 10 may be retrofitted to the existing plumbing of a hot water system, in particular a shower. The hot water inlet 12 and the cold water inlet 14 both include a connector for connecting the existing hot water pipes and cold water pipes respectively. Similarly, the outlet 16 includes a connector for connecting to the existing outlet pipe of the hot water system. It is envisaged that the present invention finds particular application in a shower or a wash basin. However, the invention is not limited to this and may be used in any suitable application where water at a suboptimal temperature may be wasted. It is also envisaged that the system 10 may be built into a cavity in the wall, for example the wall of a shower. In this embodiment the system 10 does not protrude as the system as described above would.

It will be appreciated that the flow passage 30 is arranged as a bypass flow passage, which bypasses the mixing means 18 (and non-return valves associated therewith), thereby allowing water from the hot water inlet 12 to flow towards the cold water inlet 14.

A preferred embodiment of the invention is shown in figure 3. The functioning of the water saving system 10 as shown in figure 3, is substantially similar to that of the embodiment described above with reference to figures 1 and 2. However, small differences exist, which are discussed in more detail below.

As can be seen from figure 3, the mixing means 18 is arranged directly downstream from the hot water inlet 12 and cold water inlet 14. The temperature sensor 38 is arranged downstream of the mixing means 18, and therefore senses the temperature of water after flowing through the mixing means 18.

The pump 32 is furthermore situated in a main water flow passage (which connects the mixing means 18 and the outlet 16) rather than in the circulation passage 30. It will be appreciated that, by adjusting the configurations of the first and second valve arrangements (20, 36), the pump may be utilised either to pump water through the circulation passage 30 (when the system 10 is configured in the circulating mode) or through the outlet 16. It will be appreciated that the pump 32 may now have a dual function, in that the circulation of the water from the hot water inlet 12, back to the cold water inlet 14 may be facilitated, but also, in that the pump 32 may serve as a pressure pump in low pressure water systems, to increase supply pressure or flow rate of water before flowing through the outlet 16.

The variable flow control valve 22 is situated down-stream of the pump 32.

The system 10 as shown in figure 3 still includes a non-return valve 26 situated between the mixing means 18 and the hot water inlet 12, a non return valve 28 situated between the mixing means 18 and the cold water inlet 14 and a non-return valve 34 situated in the circulation passage 30.

It will be appreciated that, initially when the system 10 is activated, and therefore configured in the circulating mode, the mixing means 18 will inhibit water from the cold water inlet 14 from flowing through the mixing means 18, and so, only water from the hot water inlet 12 will flow to the pump 32.

The configurations of the system 10 are substantially similar (in terms of the configurations of the first and second valves (20, 36)) as described above with reference to figure 1 , with the exception that the pump 32 need not be switched off during the operational mode. Furthermore, due to the layout of the system 10 as shown in figure 3 and the placement of the temperature sensor 38, no safety temperature sensing means 24 is required, since the temperature sensor 38 already measures the temperature of the water after it has been mixed in the mixing means 18. In the embodiment of figure 3, the temperature sensor 38 also performs the function of the safety temperature sensing means 24 as discussed with reference to the embodiment shown in figures 1 and 2. Therefore, when the temperature measured by the temperature sensor 38 exceeds a predetermined temperature deemed to be dangerously hot and which could scald the user, the operation of the system 10 will be automatically terminated.

Figure 4 shows a further and much simplified embodiment of the invention. The system 10 shown in figure 4 is typically used in bathroom or kitchen basins or sinks, although it can also be used in showers or other appliances. The system 10 also facilitates a circulation mode in which the system functions fundamentally in the same way as discussed above with reference to figures 1 and 2.

Flowever, the system 10 shown in figure 4 does not include mixing means 18, and the outlet 16 provides water to the user, from the hot water source 102 only. Typically, a second outlet 122 is also provided for directing water from the cold water source 104 to the user. The flow through the second outlet 122 is typically controlled with a further valve 120.

A circulation passage 30 is still provided between the hot water inlet 12 and the cold water inlet 14, for water to be pumped towards the cold water inlet 14 during the circulating mode of the system 10.

In any of the above embodiments of the invention, some of the components, and particularly the first valve 20, may be manually operated, and therefore, not operated or configured by the control system. The control system will however still receive inputs from the temperature sensor 38, and will produce an output, based on such inputs. In cases where some of the components are not electronically controlled, the output may be signals, such as light indicators. For example, in a system 10 where the first valve arrangement 20 comprises a manually operated tap, a user may initiate the circulating mode, which circulating mode may be terminated by the control system when a predetermined temperature is measured by temperature sensor 38, after which a light indicator may indicate to the user that the tap may be opened. It will readily be appreciated that variations to the above, and combinations of the features contained in the various embodiments are feasible.

Furthermore, as is illustrated in the figures, flow passages, in the form of conduits or pipes, are provided between the various components of the system 10, such as between the hot water inlet 12 and the mixing means 18, between the cold water inlet 14 and the mixing means 18, between the mixing means 18 and the outlet 16 etc. Various connections, such as elbows or T-pieces are provided to interconnect different components of the system 10. Typically, the flow passage 30 links the flow passage between the hot water inlet 12 and the mixing means 18, to the flow passage between the cold water inlet 14 and the mixing means 18.

It will be appreciated that the specific layout of the various flow passages and connections as shown in the figures, may be rearranged in various different ways to arrive at alternative layouts, while still achieving the results described herein.

It will be understood that a reference to a first position which is situated “upstream” or “downstream” of a second position, refers to a first position which is upstream or downstream (as the case may be) of the second position, when water flows in the system 10 in a normal flow direction, such as during the operative mode of the system. This “normal” flow direction therefore relates to water flowing from the cold water source, through the cold water inlet 14, through the mixing means 18 and out of the outlet 16, and water flowing from the hot water source, through the hot water inlet 12, through the mixing means 18, and out of the outlet 16. It will be understood that the physical locations of the first and second positions in this example, do not change when the flow direction of water in parts of the system is reversed (such as during the circulating mode of the system) or if no flow of water is present in the system.

It will be appreciated that the above only provides some embodiments of the invention and that there may be many variations without departing from the spirit and/or the scope of the invention. It is easily understood from the present disclosure that the particular features of the present invention, as generally described and illustrated in the figures, can be arranged and designed according to a wide variety of different configurations. In this way, the description of the present invention and the related figures are not provided to limit the scope of the invention but simply represent selected embodiments.

The skilled person will understand that the technical characteristics of a given embodiment can in fact be combined with characteristics of another embodiment, unless otherwise expressed or it is evident that these characteristics are incompatible. Also, the technical characteristics described in a given embodiment can be isolated from the other characteristics of this embodiment unless otherwise expressed.