WATER HEATER APPLIANCE FREEZE PREVENTION IN RECREATIONAL VEHICLES

FIELD OF THE INVENTION

[0001]The present subject matter relates generally to recreational vehicle water heaters, and more particularly to freeze prevention systems therein.

BACKGROUND OF THE INVENTION

[0002]Water heaters for use with recreational vehicles (RV) typically include a water tank in combination with an internal heating element. Most internal heating elements in water heaters used in recreational vehicles are dual fuel: liquid petroleum gas and electric heating. The water heater is mounted on the recreational vehicle in a convenient position connected to cold water supply and hot water outlet pipes, respectively receiving cold water from a suitable water supply source and for directing heated water for use in cooking, bathing, and the like.

[0003]Standard recreational vehicle water heaters include an exhaust tube to the outside air in order to exhaust combustion products from the water heater out of the recreational vehicle. In colder climates, such as climates reaching temperatures below forty degrees Fahrenheit (40° F.), water heater appliances may be at risk of freezing and/or being damaged by cold air. When not using the water heater appliance, there are two typical ways that users prevent freezing of the water heater; either by draining the water completely from the recreational vehicle or by filling the pipes with an anti-freeze liquid (also known as winterization).

[0004]However, problems may occur either when driving in sub-freezing conditions, or if overnight the temperature drops below freezing and the water heater appliance is not maintaining temperature to prevent freezing. Another way that other tankless water heaters prevent freezing overnight is by running the heat exchanger to prevent freezing from occurring. This is done by propane flowing, being ignited, and passing through the heat exchanger to warm up the water heater appliance. However, typically propane is turned off when traveling, and constantly running the water heater appliance consumes a large amount of propane compared to regular operation.

[0005]Accordingly, a water heater appliance with a freeze prevention system that decreases cost would be desirable. Further, a recreational vehicle with a water heater appliance that includes a freeze prevention system that operates at any given time for freeze prevention would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

[0006]Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

[0007]In one example embodiment, a water heater appliance for a recreational vehicle is provided. The water heater appliance defines a vertical direction, a lateral direction, and a transverse direction. The vertical, lateral, and transverse directions are mutually perpendicular. The water heater appliance includes a cabinet, and a heat exchanger positioned within the cabinet. The heat exchanger includes a first temperature sensor. A combustion chamber is positioned within the cabinet. The combustion chamber includes a burner assembly. The combustion chamber is in thermal communication with the heat exchanger. The water heater appliance also includes an inlet coupled to the cabinet. The inlet includes an inlet tube fluidly coupled to the heat exchanger. The inlet tube includes an inlet temperature sensor and an inlet heater. An outlet is also coupled to the cabinet. The outlet includes an outlet tube fluidly coupled to the heat exchanger. The outlet tube includes an outlet temperature sensor and an outlet heater. A controller is positioned within the cabinet. The controller is in signal communication with the inlet temperature sensor and the outlet temperature sensor. A control panel is in signal communication with the controller. The control panel includes a display. The controller is configured to monitor an inlet temperature via the inlet temperature sensor and an outlet temperature via the outlet temperature sensor, detect one of the inlet temperature and the outlet temperature below a first temperature threshold, activate a freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature below the first temperature threshold, provide a notification of the activation of the freeze prevention mode, and heat, via one or both of the inlet heater and the outlet heater, a respective one or both of the inlet tube and/or the outlet tube. The controller is also configured to detect one of the inlet temperature and the outlet temperature above a second temperature threshold, and deactivate the freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature above the second temperature threshold.

[0008]In another example embodiment, a method of operating a water heater appliance for a recreational vehicle is provided. The water heater appliance includes a cabinet, and a heat exchanger positioned within the cabinet. The heat exchanger includes a first temperature sensor. A combustion chamber is positioned within the cabinet. The combustion chamber includes a burner assembly. The combustion chamber is in thermal communication with the heat exchanger. The water heater appliance also includes an inlet coupled to the cabinet. The inlet includes an inlet tube fluidly coupled to the heat exchanger. The inlet tube includes an inlet temperature sensor and an inlet heater. An outlet is also coupled to the cabinet. The outlet includes an outlet tube fluidly coupled to the heat exchanger. The outlet tube includes an outlet temperature sensor and an outlet heater. A controller is positioned within the cabinet. The controller is in signal communication with the inlet temperature sensor and the outlet temperature sensor. A control panel is in signal communication with the controller. The control panel includes a display. The method includes monitoring an inlet temperature via the inlet temperature sensor and an outlet temperature via the outlet temperature sensor, detecting one of the inlet temperature and the outlet temperature below a first temperature threshold, activating a freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature below the first temperature threshold, providing a notification of the activation of the freeze prevention mode, and heating, via one or both of the inlet heater and the outlet heater, a respective one or both of the inlet tube and/or the outlet tube. The method also includes detecting one of the inlet temperature and the outlet temperature above a second temperature threshold and deactivating the freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature above the second temperature threshold.

[0009]These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0011]FIG. 1 provides a front view of an example embodiment of a water heater appliance for a recreational vehicle, according to aspects of the present subject matter.

[0012]FIG. 2 provides a perspective view of the water heater appliance of FIG. 1, with a door of the water heater appliance removed, according to aspects of the present subject matter.

[0013]FIG. 3 provides a perspective, sectional view of the water heater appliance of FIG. 1, according to aspects of the present subject matter.

[0014]FIG. 4 provides a side view of the water heater appliance of FIG. 1, according to aspects of the present subject matter.

[0015]FIG. 5 provides another side view of the water heater appliance of FIG. 1, according to aspects of the present subject matter.

[0016]FIG. 6 provides a schematic diagram of a freeze prevention circuit, according to aspects of the present subject matter.

[0017]FIG. 7 provides a schematic of the water heater appliance of FIG. 1 in communication with a control panel, according to aspects of the present subject matter.

[0018]FIG. 8 provides a front view of the example control panel of FIG. 7, according to aspects of the present subject matter.

[0019]FIG. 9 provides another schematic of the freeze prevention circuit of FIG. 6 in communication with a control panel, according to aspects of the present subject matter.

[0020]FIG. 10 provides a front view of the example control panel of FIG. 9, according to aspects of the present subject matter.

[0021]FIG. 11 provides a flow chart illustrating an example method of operating a water heater appliance, according to aspects of the present subject matter.

[0022]Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023]Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0024]As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). In addition, here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

[0025]Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “generally,” “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified.

[0026]Referring now to FIGS. 1 through 3, an example water heater appliance will be described in accordance with example aspects of the present subject matter. Specifically, FIG. 1 provides a front view of an example water heater appliance 100, FIG. 2 provides a perspective view of water heater appliance 100, and FIG. 3 provides a perspective, cross-sectional view of water heater appliance 100. As illustrated, water heater appliance 100 generally defines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular, such that an orthogonal coordinate system is generally defined.

[0027]According to example embodiments, water heater appliance 100 may include a cabinet 107 that is generally configured for containing and/or supporting various components of water heater appliance 100 and which may also define one or more internal chambers or compartments of water heater appliance 100. In this regard, as used herein, the terms “cabinet,” “housing,” and the like are generally intended to refer to an outer frame or support structure for appliance 100, e.g., including any suitable number, type, and configuration of support structures formed from any suitable materials, such as a system of elongated support members, a plurality of interconnected panels, or some combination thereof. It should be appreciated that cabinet 107 does not necessarily require an enclosure and may simply include an open structure supporting various elements of appliance 100. By contrast, cabinet 107 may enclose some or all portions of the interior of cabinet 107. It should be appreciated that cabinet 107 may have any suitable size, shape, and configuration while remaining within the scope of the present subject matter.

[0028]In general, cabinet 107 may extend in the transverse direction T between a front side 131 and a back side 132, in the vertical direction V between a top side 135 and a bottom side 136, and in the lateral direction L between a first side 133 and a second side 134. In general, water heater appliance 100 may include a panel, e.g., a door 102, coupled to cabinet 107, as shown in FIG. 1 in a closed position, and removed in FIG. 2 for clarity in showing within cabinet 107. In general, door 102 may be mounted to cabinet 107 via hinges 106, e.g., hinges 106 may rotatably couple door 102 to cabinet 107. Opening door 102 about hinge 106 may permit selective access to internal components within cabinet 107, such as a burner assembly 110, a heat exchanger 120 and/or, an exhaust box 200, each of which are described in greater detail below. In general, door 102 of water heater appliance 100 may include a slot, such as an exhaust port 103, for an exhaust outlet 104, as will be described in greater detail below.

[0029]In the present example embodiment, water heater appliance 100 may include a heat exchanger 120 positioned within cabinet 107. Heat exchanger 120 may generally provide heat to water flowing through water heater appliance 100, such as via thermal conduction, convection, and or radiation through walls and/or pipes of heat exchanger 120. In particular, a front wall 121, a pair of opposing sidewalls, and a rear wall 123 of heat exchanger 120 may transfer heat to a pipe 125. In general, front wall 121, sidewalls 122, and rear wall 123 of heat exchanger may generally form a rectangular shape for containing combusted fuels therein. While one example sidewall 122 is shown in FIG. 5, a person having ordinary skill in the art would understand that an opposing sidewall 122 is mirrored across front wall 121 and rear wall 123 to form a rectangular shape. Pipe 125 may generally wrap around, such as coiled around, heat exchanger 120 to receive heat from heat exchanger 120, e.g., pipe 125 may be in contact, i.e., physically touching along a length, with each of front wall 121, sidewalls 122, and rear wall 123, thereby heating water flowing within pipe 125. Further, pipe 125 may extend within heat exchanger 120, such as within the flow path of combusted fuels, for heating of water flowing therein. Thus, water heater appliance 100 may be configured for heating water by combusting liquid petroleum gas, such as liquid propane (LP).

[0030]As will be explained further below, heat exchanger may include a first temperature sensor 310 (FIG. 4). In general, water heater appliance 100 may also include a combustion chamber 112 within cabinet 107 for combusting liquid propane. As such, a burner assembly 110 may extend within combustion chamber 112, and combustion chamber 112 may be in thermal communication with heat exchanger 120, e.g., combustion chamber 112 may be thermally coupled to (in direct contact with) heat exchanger 120, whereby combusted fuel may heat water within heat exchanger 120. In general, burner assembly 110 may include a gas inlet (not labeled) and a sparker or igniter 142 for igniting fuel within combustion chamber 112. In other words, burner assembly 110 may combust fuel within combustion chamber 112, thus providing heat to heat exchanger 120 for heating water passing through water heater appliance 100. Accordingly, water may enter water heater appliance 100 and be heated by heat exchanger 120, before being distributed to other appliances or outlets for use in cooking, bathing, and the like.

[0031]In general, burner assembly 110 may be in fluid communication with a gas control valve 140 to control the flow of gas to combustion chamber 112. Burner assembly 110 may generally create combustion products, such as exhaust gases within combustion chamber 112. In general, the created combustion products may exit water heater appliance 100 to ambient atmosphere. In particular, water heater appliance 100 may include an exhaust tube 108 fluidly coupled to combustion chamber 112. For example, exhaust tube 108 may extend between an inlet 109 positioned at combustion chamber 112 and an outlet 111 along the transverse direction T. In some example embodiments, a blower assembly 144 may be fluidly coupled between combustion chamber 112 and exhaust tube 108. Blower assembly 144 may generally be configured to pull exhaust from heat exchanger 120, through exhaust tube 108, and force the exhaust out of water heater appliance 100 to ambient atmosphere.

[0032]In the present example embodiment, an exhaust box 200 may be positioned at outlet 111 of exhaust tube 108. Exhaust box 200 may generally be a rectangular, stainless-steel box. In particular, exhaust box 200 may be fluidly coupled to exhaust tube 108 and may include exhaust outlet 104, e.g., exhaust outlet 104 may be integral to exhaust box 200 and may extend through exhaust port 103 in door 102 of water heater appliance 100. As such, the created combustion products from burner assembly 110 may exit from water heater appliance 100 to ambient atmosphere from combustion chamber 112 through exhaust tube 108, into exhaust box 200, and through exhaust outlet 104.

[0033]Turning now to FIGS. 4 and 5, provided are side views of water heater appliance 100, with portions of cabinet 107 removed for clarity of the components within water heater appliance 100. In general, water heater appliance 100 may include an inlet 250 coupled to cabinet 107. For example, inlet 250 may be coupled to and extend through back side 132 of cabinet 107. In general, inlet 250 may be coupled to an inlet tube 252, e.g., within cabinet 107 inlet 250 may be fluidly coupled to inlet tube 252. Inlet tube 252 may generally be fluidly coupled to heat exchanger 120, thereby extending between inlet 250 and heat exchanger 120. As such, water heater appliance 100 may receive water from an external water source, such as a water tank or a municipal water supply, through inlet 250 and direct the water into heat exchanger 120 for heating. As will be explained further below, inlet tube 252 may include an inlet temperature sensor 302 mounted thereon and an inlet heater 304 mounted thereon.

[0034]In general, water heater appliance 100 may include an outlet 260 coupled to cabinet 107. For example, outlet 260 may be coupled to and extend through back side 132 of cabinet 107. In general, outlet 260 may be coupled to an outlet tube 262, e.g., within cabinet 107 outlet 260 may be fluidly coupled to outlet tube 262. Outlet tube 262 may generally be fluidly coupled to heat exchanger 120, thereby extending between heat exchanger 120 and outlet 260. As such, water heater appliance 100 may distribute water, e.g., heated water from heat exchanger 120, out of outlet 260 to various points of use, such as other appliances, such as a dishwasher appliance or washing machine appliance, or other points of use, including fixtures such as faucets, etc. For example, some recreational vehicles include a plurality of appliances therein, and water heater appliance 100 may be configured to supply heated water thereto. As will be explained further below, outlet tube 262 may include an outlet temperature sensor 306 mounted thereon and an outlet heater 308 mounted thereon.

[0035]Turning now to FIG. 6, provided is a schematic diagram of a freeze prevention circuit 300 of water heater appliance 100. In general, freeze prevention circuit 300 may include inlet temperature sensor 302 of inlet tube 252, inlet heater 304 of inlet tube 252, outlet temperature sensor 306 of outlet tube 262, and outlet heater 308 of outlet tube 262. In general, freeze prevention circuit 300 may be an analog circuit, e.g., distinct and separate from a controller (not shown) or microprocessor of water heater appliance 100. In particular, water heater appliance 100 may include a power supply 350 electrically coupled to freeze prevention circuit 300, such that power may be provided to freeze prevention circuit 300 and transmitted to the components thereof.

[0036]In general, inlet temperature sensor 302 may be electrically coupled in series with inlet heater 304, and outlet temperature sensor 306 may be electrically coupled in series with outlet heater 308. In particular, inlet temperature sensor 302 and inlet heater 304, as well as outlet temperature sensor 306 and outlet heater 308 may be independent circuits coupled to power supply 350. In general, inlet temperature sensor 302 and outlet temperature sensor 306 may be thermal switches. In particular, thermal switches may be electromechanical switches which open and close metallic contacts, in response to changes in temperature, to control the flow of electrical current. For example, when the temperature increases above a specified temperature, a thermal switch, such as thermal cutoff 303, 307 (FIG. 9), may open, thereby cutting off current to components further down a circuit. In the present example embodiment, when the temperature of either of first temperature sensor 310, inlet temperature sensor 302, or outlet temperature sensor 306 drops below a specified, threshold temperature, the circuit may close, thereby providing current to the component or components connected in series to the respective sensor at which the sensed temperature dropped below the threshold temperature. As such, inlet temperature sensor 302 and outlet temperature sensor 306 may be analog components. Further, inlet heater 304 and outlet heater 308 may be resistive heaters, e.g., analog components, such that freeze prevention circuit 300 may consist of only analog components.

[0037]In general, freeze prevention circuit 300 may be configured to detect a specified temperature within water heater appliance 100, and activate at least one of inlet heater 304, outlet heater 308, and heat exchanger 120 of water heater appliance 100 in response to the detection of the specified temperature. In particular, the specified temperature may include a threshold temperature, such as about fifty degrees Fahrenheit (50° F.) or less, such as about forty-five degrees Fahrenheit (45° F.) or less, such as about forty degrees Fahrenheit (40° F.), wherein detecting the specified temperature includes detecting a temperature below the threshold temperature. For example, outlet temperature sensor 306 may detect a temperature below the threshold, e.g., below about forty degrees Fahrenheit (40° F.), wherein outlet temperature sensor 306 may close and permit current/power to flow to outlet heater 308, thereby heating outlet tube 262 to restrain water within outlet tube 262 from freezing.

[0038]In some example embodiments, freeze prevention circuit 300 may activate heat exchanger 120. For example, activating heat exchanger 120 may include releasing and igniting gas within combustion chamber 112 at heat exchanger 120 to, by convection and conduction, heat up heat exchanger 120, thus restraining water within heat exchanger 120 from freezing. Additionally or alternatively, outlet heater 308 may be activated in response to outlet temperature sensor 306 detecting the temperature below the specified/threshold temperature. Additionally or alternatively, inlet heater 304, on inlet tube 252, of freeze prevention circuit 300 may be configured to activate in response to inlet temperature sensor 302 detecting the specified/threshold temperature, thus restraining water within inlet tube 252 from freezing.

[0039]As such, when the temperature of inlet tube 252, heat exchanger 120, and/or outlet tube 262 within water heater appliance 100 is detected to be below the specified/threshold temperature, freeze prevention circuit 300 may be configured to activate inlet heater 304 (e.g., in response to inlet temperature sensor 302 on inlet tube 252), heat exchanger 120 (e.g., in response to first temperature sensor 310 on heat exchanger 120), and outlet heater 308 (e.g., in response to outlet temperature sensor 306 on outlet tube 262). Accordingly, freeze prevention circuit 300 may aid in preventing water heater appliance 100 from freezing between inlet 250, heat exchanger 120, and outlet 260 with electricity and without the use of a controller/microprocessor.

[0040]Turning now to FIGS. 7 and 8, water heater appliance 100 may generally include a control panel 410. In the present example embodiment, control panel 410 may be positioned separate from water heater appliance 100. For example, control panel 410 may be a wall-mounted user interface, or an external appliance controller, positioned within about five feet (5 ft), such as within about eight feet (8 ft), such as within about fifteen feet (15 ft) of water heater appliance 100. Control panel 410 may represent a general-purpose Input/Output (“GPIO”) device or functional block for water heater appliance 100. In some embodiments, control panel 410 may include or be in operative communication with a plurality of user input devices 412, such as one or more, or a variety, of digital, analog, electrical, mechanical, or electro-mechanical input devices including control knobs, push buttons, toggle switches, selector switches, and touch pads.

[0041]Additionally, water heater appliance 100 may include a display 414, such as a digital or analog display device generally configured to provide visual feedback regarding the operation of water heater appliance 100. For example, display 414 may be provided on control panel 410 and may include one or more status lights, screens, or visible indicators. According to example embodiments, user input devices 412 and display 414 may be integrated into a single device, e.g., including one or more of a touchscreen interface, a capacitive touch panel, a liquid crystal display (LCD), a plasma display panel (PDP), or other informational or interactive displays.

[0042]Water heater appliance 100 may further include or be in operative communication with a processing device, e.g., controller 400, that may be generally configured to facilitate appliance operation. In this regard, inlet temperature sensor 302, outlet temperature sensor 306, control panel 410, user input devices 412, and display 414 may be in signal communication with controller 400 such that controller 400 may determine temperature measurements from inlet temperature sensor 302, may receive user inputs from user input devices 412, may display information using display 414, and may otherwise regulate operation of water heater appliance 100. For example, signals generated by controller 400 may operate water heater appliance 100, including any or all system components, subsystems, or interconnected devices, in response to the interaction of user input devices 412 and other control commands. Control panel 410 and other components of appliance 100 may be in communication with controller 400 via, for example, one or more signal lines, e.g., wire 420, or shared communication busses. In this manner, Input/Output (“I/O”) signals may be routed between controller 400 and various operational components of water heater appliance 100.

[0043]As used herein, the terms “processing device,” “computing device,” “controller,” or the like may generally refer to any suitable processing device, such as a general or special purpose microprocessor, a microcontroller, an integrated circuit, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), a logic device, one or more central processing units (CPUs), a graphics processing units (GPUs), processing units performing other specialized calculations, semiconductor devices, etc. In addition, these “controllers” are not necessarily restricted to a single element but may include any suitable number, type, and configuration of processing devices integrated in any suitable manner to facilitate appliance operation. Alternatively, controller 400 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND/OR gates, and the like) to perform control functionality instead of relying upon software.

[0044]Controller 400 may include, or be associated with, one or more memory elements or non-transitory computer-readable storage mediums, such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks, or other suitable memory devices (including combinations thereof). These memory devices may be a separate component from the processor or may be included onboard within the processor. In addition, these memory devices can store information and/or data accessible by the one or more processors, including instructions that can be executed by the one or more processors. It should be appreciated that the instructions can be software written in any suitable programming language or can be implemented in hardware. Additionally, or alternatively, the instructions can be executed logically and/or virtually using separate threads on one or more processors.

[0045]For example, controller 400 may be operable to execute programming instructions or micro-control code associated with an operating cycle of water heater appliance 100. In this regard, the instructions may be software or any set of instructions that when executed by the processing device, cause the processing device to perform operations, such as running one or more software applications, displaying a user interface, receiving user input, processing user input, etc. Moreover, it should be noted that controller 400 as disclosed herein is capable of and may be operable to perform any methods, method steps, or portions of methods as disclosed herein. For example, in some embodiments, methods disclosed herein may be embodied in programming instructions stored in the memory and executed by controller 400.

[0046]The memory devices may also store data that can be retrieved, manipulated, created, or stored by the one or more processors or portions of controller 400. The data can include, for instance, data to facilitate performance of methods described herein. The data can be stored locally (e.g., on controller 400) in one or more databases and/or may be split up so that the data is stored in multiple locations. In addition, or alternatively, the one or more database(s) can be connected to controller 400 through any suitable network(s), e.g., network 430 (FIG. 7), such as through a high bandwidth local area network (LAN) or wide area network (WAN). In this regard, for example, controller 400 may further include a communication module or interface that may be used to communicate with one or more other component(s) of water heater appliance 100, controller 400, control panel 410, or any other suitable device, e.g., via any suitable communication lines (e.g., wire 420) or network(s) (e.g., network 430) and using any suitable communication protocol. The communication interface can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, or other suitable components.

[0047]As stated above, display 414 may include one or more status lights, screens, or visible indicators. In particular, display 414 may include a set-point temperature indicator 416, a freeze prevention mode indicator 417 (FIG. 9), and an inlet temperature indicator 418. In general, set-point temperature indicator 416 may display/project a numerical value indicative of the set-point temperature set by a user at control panel 410. In general, freeze prevention mode indicator 417 may display/project an icon or symbol indicative of a freeze prevention mode being active. In general, inlet temperature indicator 418 may display/project a numerical value indicative of an inlet temperature, e.g., an instantaneous temperature of incoming water into water heater appliance 100, measured by inlet temperature sensor 302. For example, display 414 of control panel 410 may display/project/illuminate the inlet temperature, e.g., the numerical value, such as displaying “65”. In particular, inlet temperature indicator 418 may display/project/illuminate the inlet temperature on display 414 of control panel 410.

[0048]Turning now to FIGS. 9 and 10, provided in FIG. 9 is another schematic of freeze prevention circuit 300 in communication with control panel 410 through controller 400, and FIG. 10 illustrates an example embodiments of control panel 410. As described above, freeze prevention mode indicator 417 may be an icon or symbol indicative of a freeze prevention mode being active. In general, the icon may be any suitable shape, pattern, word, or graphical symbol, such as an illuminated “box” shape, may say “Heating” and/or may be a “snowflake” shape. In further example embodiments, the icon may be animated, e.g., an illuminated “snowflake” shape may rotate or spin on display 314. As will be described further herein, display 414 may display/project an error code on display 414 of control panel 410.

[0049]As shown in FIG. 9, freeze prevention circuit 300 may include an inlet thermal cutoff switch 303 on inlet tube 252 and an outlet thermal cutoff switch 307 on outlet tube 262. In some example embodiments, inlet thermal cutoff switch 303 and outlet thermal cutoff switch 307 may be separate, e.g., isolated, from inlet temperature sensor 302 and outlet temperature sensor 306, respectively. In general, inlet heater 304 may activate in response to the activation of inlet thermal cutoff switch 303, and outlet heater 308 may activate in response to the activation of outlet thermal cutoff switch 307.

[0050]Referring now to FIG. 11, illustrated is a method 1100 of operating a water heater appliance. Method 1100 may include steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the steps of any of the methods discussed herein may be adapted, rearranged, expanded, omitted, or modified in various ways without deviating from the scope of the present disclosure. Moreover, although aspects of method 1100 are explained using water heater appliance 100 as an example, it should be appreciated that method 1100 may be applied to the operation of any suitable water heater appliance.

[0051]At 1110, method 1100 may generally include monitoring an inlet temperature via the inlet temperature sensor and an outlet temperature via the outlet temperature sensor. In particular, controller 400 may monitor the inlet temperature via inlet temperature sensor 302 and may monitor the outlet temperature via outlet temperature sensor 306. In some example embodiments, inlet temperature indicator 418 may display/project/illuminate the monitored inlet temperature on display 414 of control panel 410.

[0052]At 1120, method 1100 may generally include detecting one of the inlet temperature and the outlet temperature below a first temperature threshold. In particular, controller 400 may detect one or both of the inlet temperature and/or the outlet temperature below a first temperature threshold. In general, the first temperature threshold may be between forty degrees Fahrenheit (40° F.) and fifty seven degrees Fahrenheit (57° F.), such as between forty one degrees Fahrenheit (41° F.) and fifty degrees Fahrenheit (50° F.), such as between forty two degrees Fahrenheit (42° F.) and forty five degrees Fahrenheit (45° F.).

[0053]At 1130, method 1100 may generally include activating a freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature below the first temperature threshold. In particular, controller 400 may activate a freeze prevention mode, e.g., e.g., a mode configured to heat water heater appliance 100 and reduce likelihood of water heater appliance 100 from freezing, in response to detecting one of the inlet temperature and the outlet temperature below the first temperature threshold.

[0054]At 1140, method 1100 may generally include providing a notification of the activation of the freeze prevention mode. In particular, providing a notification of the activation of the freeze prevention mode may include displaying freeze prevention mode indicator 417 on display 414 of control panel 410 in response to the activation of the freeze prevention mode. Furthermore, in some example embodiments, freeze prevention mode indicator 417 of water heater appliance 100 may advantageously indicate, such as to notify a user, when propane is being burned.

[0055]At 1150, method 1100 may generally include heating, via one or both of the inlet heater and the outlet heater, a respective one or both of the inlet tube and/or the outlet tube. In particular, inlet thermal cutoff switch 303 may activate in response to detecting the inlet temperature below the first temperature threshold, whereby inlet heater 304 may heat inlet tube 252 and water therein, and/or outlet thermal cutoff switch 307 may activate in response to detecting the outlet temperature below the first temperature threshold, whereby outlet heater 308 may heat outlet tube 262 and water therein.

[0056]At 1160, method 1100 may generally include detecting one of the inlet temperature and the outlet temperature above a second temperature threshold. In particular, controller 400 may detect one or both of the inlet temperature and/or the outlet temperature above a second temperature threshold. In general, the second temperature threshold may be between fifty eight degrees Fahrenheit (58° F.) and seventy degrees Fahrenheit (70° F.), such as between fifty nine degrees Fahrenheit (59° F.) and sixty six degrees Fahrenheit (66° F.), such as between sixty degrees Fahrenheit (60° F.) and sixty three degrees Fahrenheit (63° F.).

[0057]At 1170, method 1100 may generally include deactivating the freeze prevention mode in response to detecting one of the inlet temperature and the outlet temperature above the second temperature threshold. In particular, controller 400 may deactivate the freeze prevention mode in response to detecting one or both of the inlet temperature and/or the outlet temperature above the second temperature threshold. Additionally, method 1100 may include unilluminating freeze prevention mode indicator 417 on display 414 of control panel 410 in response to the deactivation of the freeze prevention mode.

[0058]Method 1100 may further include detecting one of the inlet temperature and the outlet temperature below a third temperature threshold. In particular, controller 400 may detect one or both of the inlet temperature and/or the outlet temperature below a third temperature threshold. In general, the third temperature threshold may be between thirty degrees Fahrenheit (30° F.) and thirty nine degrees Fahrenheit (39° F.), such as between thirty one degrees Fahrenheit (31° F.) and thirty seven degrees Fahrenheit (37° F.), such as between thirty two degrees Fahrenheit (32° F.) and thirty five degrees Fahrenheit (35° F.).

[0059]Moreover, method 1100 may include displaying an error code on the display of the control panel in response to detecting one of the inlet temperature and the outlet temperature below the third temperature threshold. In particular, in response to detecting the inlet temperature below the third temperature threshold, controller 400 may display/project/illuminate an error code in place of set-point temperature indicator 416 on control panel 410. For example, as seen in FIG. 10, in response to detecting the inlet temperature below the third temperature threshold, controller 400 may display/project/illuminate an error code “FP1” in place of set-point temperature indicator 416 on control panel 410. In particular, in response to detecting the outlet temperature below the third temperature threshold, controller 400 may display/project/illuminate an error code in place of set-point temperature indicator 416 on control panel 410, such as an error code “FP2” in place of set-point temperature indicator 416. As such, an error code “FP1” would be indicative of an error with inlet thermal cutoff switch 303, and an error code “FP2” would be indicative of an error with outlet thermal cutoff switch 307. In general, the error code may be any suitable word, phrase, abbreviation, or alphanumerical combination assigned to an individual one of the thermal cutoff switches 303, 307.

[0060]In general, the error code displayed on display 414 of control panel 410 may be dismissed, such as to continue use of water heater appliance 100. For example, a user may dismiss the error code by performing a user input event. In particular, a user input event may include pressing, such as depressing or engaging, one user input device 412 of the plurality of user input devices 412 on control panel 410 for a predetermined period of time. In general, any suitable number of hands, fingers, other bodily appendages, such as elbows or toes, or tools, such as a stylus, may be used to perform a user input event. In general, the predetermined period of time may be between ten seconds (10 s) and twenty seconds (20 s), such as between eleven seconds (11 s) and nineteen seconds (19 s), such as between twelve seconds (12 s) and eighteen seconds (18 s).

[0061]As may be seen from the above, a water heater appliance for a recreational vehicle may include a freeze prevention circuit including thermal switches and heaters connected in series, such that the heaters may be activated upon the thermal switches detecting a temperature below a threshold temperature. A control panel of the water heater appliance may indicate the activation of the heaters, e.g., the activation of a freeze prevention mode, when the heaters are activated. Accordingly, the above water heater appliance may advantageously alert a user when the freeze prevention mode is active. The water heater appliance may advantageously eliminate filling the water heater appliance with anti-freeze liquid (winterizing), while also providing a freeze prevention system that may operate at any given time.

[0062]This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.