Patent Application
20250043993
Embodiments relate to water heaters.
Storage water heaters utilize one or more heating sources to heat a fluid (for example, water) in a storage tank. In electric water heaters, electronic controls may utilize one or more relays to selectively activate and deactivate electric heating elements of the tank. Such relays may include at least a pair of supply contacts and one or more separate control inputs for closing and opening the supply contacts (for example, a coil). In some systems, the relay(s), in particular, the contacts thereof, may be normally open until a demand for heat is determined by the electronic controls. In response to the heat demand, the contacts are closed via control input(s). When the contacts are closed, power is provided through the contacts and to the heating element. When the demand for heat is satisfied, the contacts of the relay are operated to be opened. By way of example, the contacts may be opened by a return spring force that is no longer resisted by a magnetic force generated in response to a signal from the control input(s).
When the contacts of a relay are opened from a closed position, arcing may occur across the contacts due to the magnitude of current that is interrupted during relay operation. Over time, this arcing at the contact interface may cause the contact surfaces (which may be made of a low resistance metal or metal alloy, such as silver or silver alloy) to degrade, resulting in roughened contact surfaces. Eventually, this roughening of the contact surfaces may create weak welds due to localized melting of the contact surfaces during operation, which may begin causing the contacts to stick together. After several opening-closing cycles of the relay, over time, further degradation of the contact surfaces may increase the strength of the welding of contact surfaces, which may eventually result in the relay contacts remaining stuck together despite the relay being operated to open. As a result, the relay may continue to provide power to the heating element despite the heat demand being satisfied and, thus, heat the fluid of the tank beyond a desired setpoint temperature.
Therefore, there is a need for detecting and mitigating contact welding of a relay for a heating element of a water heating system.
Accordingly, one embodiment provides a method of mitigating a contact weld of a first relay for selectively transmitting power to a first heating element of a water heating system. The method includes providing a signal to open the first relay, determining, following providing the signal to open the first relay, a first temperature measurement of a portion of a tank of the water heating system via a temperature sensor, and determining whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold. The method further includes activating, in response to the difference between the first temperature measurement and the first target setpoint exceeding the first predetermined threshold, a vibration device for a predetermined time period, the vibration device being positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay.
Another embodiment provides a water heating system including a tank, a first heating element coupled to a first portion of the tank, a temperature sensor configured to measure a temperature of the first portion of the tank, a first relay configured to selectively transmit power to the first heating element, a vibration device positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay, and a controller having an electronic processor and a memory. The controller is configured to provide a signal to open the first relay, determine, following providing the signal to open the first relay, a first temperature measurement via the temperature sensor of the first portion of the tank, and determine whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold. The controller is further configured to activate, in response to the difference between the first temperature measurement and a first target setpoint exceeding the first predetermined threshold, the vibration device for a predetermined time period.
Yet another embodiment provides a method of mitigating a contact weld of a first relay for selectively transmitting power to a first heating element of a water heating system. The method includes providing a signal to open the first relay, determining, following providing the signal to open the first relay, a first temperature measurement of a portion of a tank of the water heating system via a temperature sensor, and determining whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold. The method further includes closing, in response to the difference between the first temperature measurement and a first target setpoint exceeding the first predetermined threshold, a second relay of the water heating system, wherein a combined power draw of both the first relay and the second relay exceeds a circuit breaker limit.
Another embodiment provides a water heating system including a tank, a first heating element coupled to a first portion of the tank, a second heating element coupled to a second portion of the tank, a temperature sensor configured to measure a temperature of the first portion of the tank, a first relay configured to selectively transmit power to the first heating element, a second relay configured to selectively transmit power to the second heating element, a vibration device positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay, and a controller having an electronic processor and a memory. The controller is configured to provide a signal to open the first relay, determine, following providing the signal to open the first relay, a first temperature measurement via the temperature sensor of the first portion of the tank, and determine whether a difference between the first temperature measurement to a first target setpoint exceeds a first predetermined threshold. The controller is further configured to close, in response to the difference between the first temperature measurement to a first target setpoint exceeding the first predetermined threshold, the second relay, wherein a combined power draw of both the first relay and the second relay exceeds a circuit breaker limit.
Other aspects of the application will become apparent by consideration of the detailed description and accompanying drawings.
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.
It should also be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be utilized to implement the embodiments provided herein. It should also be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be used to implement the invention. In addition, it should be understood that embodiments may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processors. As such, it should be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be utilized to implement the invention. For example, “control units” and “controllers” described in the specification can include one or more processors, one or more application specific integrated circuits (ASICs), one or more memory modules including non-transitory computer-readable media, one or more input/output interfaces, and various connections (e.g., a system bus) connecting the components.
It will be appreciated that some embodiments may be comprised of one or more electronic processors such as microprocessors, digital signal processors, customized processors, and field programmable gate arrays (FPGAs) and unique stored program instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the method and/or apparatus described herein. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used.
Moreover, some embodiments may be implemented as a computer-readable storage medium having computer readable code stored thereon for programming a computer (e.g., comprising an electronic processor) to perform a method as described and claimed herein. Examples of such computer-readable storage media include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) and a Flash memory. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.
It should be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. In some examples, the illustrated components may be combined or divided into separate software, firmware and/or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among multiple different devices. Accordingly, in the claims, if an apparatus, method, or system is claimed, for example, as including a controller, control unit, electronic processor, computing device, logic element, module, or other element configured in a certain manner, for example, to perform multiple functions, the claim or claim element should be interpreted as meaning one or more of such elements where any one of the one or more elements is configured as claimed, for example, to make any one or more of the recited multiple functions, such that the multiple elements, as a set in a collective nature, perform the multiple functions.
In this specification, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “has,” “having,” “includes,” “including,” “contains,” “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a,” “has . . . a,” “includes . . . a,” or “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially,” “essentially,” “approximately,” “about,” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1% and in another embodiment within 0.5%. A device or structure that is “configured” in a certain way is configured in at least that way but may also be configured in ways that are not listed.
A water inlet line 120 and a water outlet line 125 may be in fluid communication with the water tank 105 of the water heater 100. In some embodiments, the water inlet line 120 and the water outlet line 125 are in fluid communication with the water tank 105 at a top portion of the water heater 100. In other embodiments, the water inlet line 120 may be at a bottom portion of the water heater 100, while the water outlet line 125 is at the top portion of the water heater 100. The inlet line 120 includes an inlet opening 130 for adding cold water to the water tank 105, and the outlet line 125 includes an outlet opening 135 for withdrawing hot water from the water tank 105 for delivery to a user.
The water heater 100 includes a first heating element 140, a temperature sensor 145, and a controller housing 146 including an electronic controller 300 (described in more detail below in regard to
The second heating element 150 is attached to a second portion of the water tank 105 and extends into the water tank 105 to heat water stored in the second portion of the water tank 105. The second heating element 150, as explained in more detail below, is also configured to be selectively activated and deactivated by the electronic controller 300. When activated, the second heating element 150 heats the water stored in the second portion of the water tank 105.
The heating elements 140, 150 may each be any kind of suitable electrically-powered heating device. For example, in some embodiments, either or both of the heating elements 140, 150 is an electric resistance heating element.
Although illustrated as having two heating elements 140, 150, the water heater 100, as mentioned above, may have any number of heating elements. Furthermore, although the first heating element 140 is illustrated as being disposed in a lower portion of the tank 105 and the second heating element 150 is disposed within an upper portion of the water tank 105, it should be understood that any number of heating elements of the water heater 100 may be disposed anywhere at any portion within the tank 105. The application may be used with other kinds of fluid heating apparatus for heating a conductive fluid and having other heating element designs and arrangements than those illustrated and described herein.
The temperature sensor 145 is positioned in the first portion of the water tank 105 (heated by the first heating element 140) to determine a temperature of the fluid stored in the first portion of the water tank 105. In some embodiments, the temperature sensor 145 may be coupled to an exterior or an interior surface of the water tank 105. Additionally, the temperature sensor 145 may be a thermistor type sensor, a thermocouple type sensor, a semiconductor-based sensor, a resistance temperature detector, and the like. The temperature sensor 145 is coupled to the controller 300 to provide temperature information (for example, the sensed temperature of the first portion of the water tank 105) to the controller housing 146. In some embodiments, the water tank 105 may include one or more additional temperature sensors located at various positions around the water tank 105. For example, in some embodiments the water heater 100 may include another temperature sensor positioned in the second portion of the water tank 105 to determine a temperature of the water in the second portion of the water tank 105 (heated by the second heating element 150). As another example, the water tank 105 may be divided into three or more portions and a temperature sensor may be positioned in each portion.
The controller 300 receives power from the AC power source 205. In some embodiments, the AC power source 205 provides 120 VAC at a frequency of approximately 50 Hz to approximately 60 Hz. In some embodiments, the AC power source 205 provides approximately 220 VAC at a frequency of approximately 50 Hz to approximately 60 Hz. In some embodiments, the control system 200 also includes a power regulator 225 that converts the power from the AC power source 205 to a nominal voltage (for example, a DC voltage), and provides the nominal voltage to the controller 300 for operation.
The first relay 210 is coupled to the first heating element 140. The first relay 210 receives the control signals via, for example, a first control terminal, from the controller 300 to selectively open or close. When closed, the first relay 210 transmits driving power, via, for example, a first power output terminal, to the first heating element 140, activating the first heating element 140. When open, the first relay 210 discontinues providing driving power to the first heating element 140, thus deactivating the first heating element 140.
The second relay 215 is coupled to the second heating element 150. The second relay 215 receives the control signals via, for example, a second control terminal, from the controller 300 to selectively open or close. When closed, the second relay 215 transmits driving power, via, for example, a first power output terminal, to the second heating element 150, activating the second heating element 150. When open, the second relay 215 discontinues providing driving power to the second heating element 150, thus deactivating the second heating element 150.
The relays 210, 215 may be any kind of suitable normally-open relay device. For example,
The relay 400 includes contacts 402A and 402B and an electromagnetic coil 404 disposed around an electromagnetic core 406. The contact 402A is a moveable contact disposed on an armature 408 including a spring contact blade 410 and is connected to a power supply 412A (for example, the AC power source 205). The contact 402B is a stationary contact connected to an output load 412B (for example, the heating element 140 or 150). To close the relay 400, the electromagnetic coil 404 is supplied with a low DC voltage (for example, approximately 12 volts), which induces an electromagnetic field within the electromagnetic core 406. The field pulls against the spring contact blade 410 and pulls the armature 408 towards the core 406, closing the contact 402A onto the contact 402B and allowing driving power from the power supply 412A through to the output load 412B. To open the relay 400, power through the coil 404 is stopped, discontinuing the induced electromagnetic field within the core 406. The spring contact blade 410 thus pulls the armature 408 away from the core 406, forcing the contacts 402A and 402B apart.
Returning to
The vibration device 220, in particular, is positioned such that any resulting vibration produced from an activation of the vibration device 220 is transmitted to at least one of the relays 210, 215. For example, as illustrated in
The electronic processor 305 may include one or more microprocessors, an application-specific integrated circuit (ASIC), or another suitable electronic device. The electronic processor 305 obtains and provides information (for example, from the memory 310), and processes the information by executing one or more software instructions or modules, capable of being stored, for example, in a random access memory (“RAM”) area of the memory 310 or a read only memory (“ROM”) of the memory 310, or another non-transitory computer readable medium (not shown). The software can include firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic processor 305 is configured to retrieve from the memory 310 and execute, among other things, software related to the control processes and methods described herein.
The memory 310 stores algorithms and/or programs used to control the first heating element 140 (via the first relay 210), the second heating element 150 (via the second relay 215), and other components of the water heater 100. The memory 310 may also store operational data of the water heater (for example, which heating element 140, 145 has been previously activated, historical data, usage patterns, and the like) to help control the water heater 100.
The electronic processor 305 may include one or more of a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. The electronic processor 305 is coupled to the memory 310, the temperature sensor 145, the first relay 210, the second relay 215, the vibration device 220, and the user input/output interface 320. The electronic processor 305 receives temperature signals from the temperature sensor 145. In addition, the electronic processor 305 may access the programs, algorithms, and/or thresholds stored in the memory 310 to control the water heater 100 accordingly. Based on the received temperature signals, the electronic processor 305 generates and outputs respective control signals to the first relay 210 and the second relay 215 (for example, to activate and deactivate a respective electromagnetic coil of each relay 210, 215, such as the coil 404 of
The input/output interface 320 is configured to provide aspects of a human machine interface (e.g., a keypad, switches, buttons, soft keys, indictor lights (e.g., light emitting diodes), a microphone, a speaker, a camera, and the like) to interact with the controller 300 to output information and/or receive user inputs regarding the operation of the water heater 100 (for example, a temperature setpoint at which water is to be delivered from the water tank 105). For example, in some embodiments, the electronic controller 300 further includes a display 322. The display 322 is a suitable display such as, for example, a liquid crystal display (LCD) touch screen, or an organic light-emitting diode (OLED) touch screen. In some embodiments, the electronic controller 300 implements a graphical user interface (GUI) (for example, generated by the electronic processor 305, from instructions and data stored in the memory 310, and presented on the display 322), that enables a user to interact with the water heater 100. In some embodiments, the electronic controller 300 enables display remotely, for example, using a display of another electronic device separate from the water heater 100.
The electronic processor 305 controls the input/output interface 320 to output information to the user in the form of, for example, graphics, alarm sounds, and/or other known output devices. The input/output interface 320 may be used to control and/or monitor the water heater 100. For example, the input/output interface 320 may be operably coupled to the electronic processor 305 to control temperature settings of the water heater 100. For example, using the input/output interface 320, a user may set one or more temperature setpoints for the water heater 100.
The input/output interface 320 may be configured to display conditions or data associated with the water heater 100 in real-time or substantially real-time. For example, but not limited to, the input/output interface 320 may be configured to display (via the display 322) measured electrical characteristics of the heating elements 140, 150, the temperature sensed by temperature sensor 145, relay fault warnings (as described in more detail below) etc. The input/output interface 320 may also include a “power on” indicator and an indicator for each heating element 140, 150 to indicate whether the element is active.
The input/output interface 320 may be mounted on the shell 110 of the water heater 100 (for example, as part of the controller 300 illustrated in
In some embodiments, the controller 300 may include a transceiver 324 (for example, also shown in
In some embodiments, the input/output interface 320, the memory 310, and/or other components of the controller 300 are modular and separate from the electronic processor 305. In other words, some of the components of the controller 300 may be manufactured separately as add-on devices to be connected to the electronic processor 305. In some embodiments, the controller 300 may be communicatively coupled to an external device (for example, a wireless control panel, a smartphone, a laptop computer, and the like) through, for example, a remote network, a transceiver (for example, the transceiver 324), and the like (which is not shown).
The method 600 starts at block 602, during a heat demand period of the water heater 100. During the heat demand period the electronic processor 305 sends a control signal to the the first relay 210 to close and, thus, activate the first heating element 150. While the first heating element is active, the electronic processor 305 may monitor (periodically or continuously) a temperature measured by the temperature sensor 145 within the first portion of the tank 105 and compare the measured temperature to a target setpoint.
The electronic processor 305 is configured to provide/transmit a control signal to open the first relay 210 in response to determining that the measured temperature has reached the target setpoint (block 604). Following providing the signal to open the first relay 210, after a predetermined amount of time, at block 606, the electronic processor 305 determines, via the temperature sensor 145, a first temperature measurement of the first portion of the tank 105 of the water heating system 10. The temperature measurement reflects a present temperature characteristic of the first portion of the tank 105. The temperature measurement may be a single measurement in time, an average temperature determined from a plurality of temperature measurements, or a change in temperature over time.
At block 608, the electronic processor 305 determines a difference between the first temperature measurement and the target setpoint and, at block 610, determines whether the difference exceeds a first predetermined threshold. As described in above, in instances where the contacts of a relay (for example, the first relay 210) are welded together, the contacts may remain closed despite a control command to the particular relay to open. This results in the respective heating element(s) connected to a power supply by the relay to remain active and, thus, continue heating the fluid within the tank. Thus, when a measured temperature of the fluid of the tank 105 exceeds the target setpoint by a particular amount (for example, approximately 10° F.) following some time after a control signal to the relay to open, this may indicate that the contacts of the relay are welded/stuck together.
Thus, at block 612, the electronic processor 305 activates the vibration device 220 for a predetermined amount of time (for example, approximately 30 seconds) in response to the difference between the first temperature measurement to a first target setpoint exceeding the first predetermined threshold. As mentioned above, the vibration device 220 is positioned such that a resulting vibration from an activation of the vibration device 220 is transmitted to the first relay 210. By providing vibrations to the first relay 210, the weld between the contacts of the relay 210 may be weakened and/or broken, thus opening the relay 210. If the difference does not exceed the first target setpoint, the electronic processor 305 does not activate the vibration device 220 and continues normal heating operations of the water heating system 10 (block 614).
At block 616, after deactivating the vibration device 220 following the predetermined amount of time, the electronic processor 305 determines a second temperature measurement, via the temperature sensor 145, of the fluid within the tank 105 of the water heating system 10. The electronic processor 305 then determines whether a difference between the second temperature measurement to a second target setpoint exceeds a second predetermined threshold (block 618). In some embodiments, the second predetermined threshold is greater than the first predetermined threshold of block 610. The electronic processor 305, based on the comparison, determines whether the temperature of the fluid within the first portion of the tank 105 has increased significantly from the first temperature measurement at block 606 (for example, 5° F.). In instances where the difference between the second temperature measurement and the second target setpoint exceeds the second predetermined threshold, the electronic processor 305 returns to block 612 and activates the vibration device 220. The method 600 may repeat blocks 612-620 (each iteration of which referred to herein as a contact weld mitigation cycle) until the difference between the second temperature measurement and the second target setpoint no longer exceeds the second predetermined threshold. For each subsequent contact weld mitigation cycle, the target setpoint and/or the predetermined threshold of blocks 618 and 620 respectively may automatically be adjusted accordingly.
In some embodiments, the electronic processor may continue to perform a predetermined number of contact weld mitigation cycles (for example, three times) before automatically moving to block 622. In some instances, for each subsequent contact weld mitigation cycle, the predetermined time period, a vibration frequency, and/or a vibration amplitude of the vibration resulting from the activation of the vibration device 220 may be increased by a predetermined amount. For example, an amplitude of the resulting vibration from activating the vibration device 220 at block 612 may be increased when performed again during a subsequent contact weld mitigation cycle.
In some embodiments, as mentioned above, the system 200 may include more than one vibration device 220 positioned such that vibrations resulting from activating the respective vibration device are transmitted to the relay 210. In such embodiments, the electronic processor 305 may operate a different vibration device at one or more different positions for each subsequent contact weld mitigation cycle.
If the difference between the second temperature measurement and the second target setpoint does not exceed the second predetermined threshold, the contact weld mitigation mode ends at block 622. In some embodiments, at block 622, the electronic processor 305 may provide a warning (for example, flashing a light, providing an audible alert, displaying an error code, etc.) to a user of the water heating system 10 (for example, via the input/output interface 320) that the contacts of the relay 210 are sticking may need to be cleaned and/or replaced. At block 622, the electronic processor 305 may deactivate heating operations of the water heater 100. In some embodiments, a different type of warning may be provided based on how may contact weld mitigation cycles were performed. For example, the more contact weld mitigation cycles performed before block 622 was reached (whether due to the difference at block 620 failing to exceed the predetermined threshold or a maximum number of contact weld mitigation cycles have been performed) the more severe of a warning or action may be performed. For example, if only one contact weld mitigation cycle is performed and the difference at block 620 falls below the threshold, the electronic processor 305 may generate a warning to a user but continue normal heating operations of the water heater 100. However, if a number of contact weld mitigation cycles performed exceeds a particular threshold, the electronic processor 305 may generate a different warning and halt heating operations of the water heater (even if the difference determined at block 620 exceeds the predetermined threshold).
In addition or alternative to performing blocks 612 of the method 600, the electronic processor 305 may be configured to perform one or more additional methods to mitigate the possible contact welding of the first relay 210. For example, in some embodiments, the electronic processor 305, in response to determining that the difference between a temperature measurement and a first target setpoint exceeds a predetermined threshold at block 610, is configured to cycle the voltage provided to a coil (for example, the electromagnetic coil 404) of the relay 210. The voltage cycling of the coil (for example, two second on and two seconds off) may loosen the contacts from each other as the contact of the armature of the relay is iteratively pulled toward the stationary contact during the on cycle and pulled back by the spring contact blade during the off cycle.
As another example, in some embodiments, in addition or as an alternative to performing block 612 of the method 600, the electronic processor 305, in response to determining that the difference between a temperature measurement and a first target setpoint exceeds a predetermined threshold at block 610, may be configured to close the second relay 215. During normal heating operation, only one heating element 140, 150 may normally be active at a time, as the combined power draw of both heating elements 140, 150 may exceed a circuit breaker limit of a circuit breaker (not shown) of the power source 205 (for example, approximately more than 80% of its amperage rating). Thus, by purposefully closing the second relay 215, the circuit breaker may be thrown and power provided from the power source 205 to the rest of the heating element control system 200 is interrupted, thus stopping unwanted power through the relay 210. In such embodiments, the water heating system 10 may include an electronic latch (not shown) that is configured to be engaged such that when the circuit breaker is reset and power is supplied again to the water heater 100, the electronic controller 300 may detect the state of the latch and provide a warning to a user indicative of the contact weld fault.
Thus, this application describes, among other things, a systems and methods for detecting and mitigating contact welding of a relay for a water heating system.
In the foregoing specification, specific embodiments are described. However, one of ordinary skill in the art appreciates that various modifications and changes may be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings.
Various features and advantages of the embodiments presented herein are set forth in the following claims.
This application claims the benefit of provisional patent application No. 63/516,629, filed on Jul. 31, 2023, the entire contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63516629 | Jul 2023 | US |
