Backwater fault detection method, gas water heater and storage medium

Abstract

This application relates to a method for detecting a recirculating water heater malfunction, a gas water heater, and a storage medium. The method includes: acquiring the current water temperature after the gas water heater has completed its preheating cycle; wherein the current water temperature is detected by a temperature sensor; determining the temperature fluctuation range based on the current water temperature; and determining that the recirculating water heater malfunctions if the temperature fluctuation range exceeds a preset range. By installing a temperature sensor between the solenoid valve and the check valve of the recirculating water heater to detect the current water temperature, since the solenoid valve and check valve are closed after preheating, the current water temperature between them will not fluctuate significantly. If the detected temperature fluctuation range exceeds the preset range, it indicates that the solenoid valve or check valve of the recirculating water heater has malfunctioned, thus quickly determining whether the recirculating water heater is faulty and facilitating troubleshooting.

Description

Technical Field

[0001] This application relates to the field of gas water heater fault detection technology, and in particular to a method for detecting a return water fault, a gas water heater, and a storage medium. Background Technology

[0002] Currently, zero-cold-water gas water heaters typically employ a mechanical or electronic recirculation system to achieve circulating preheating, creating a closed-loop circulation system between the external water system and the gas water heater. Electronic recirculation systems generally contain components such as temperature sensors, solenoid valves, and check valves. However, the solenoid valves and check valves only have on / off functions and lack feedback capabilities. Therefore, if a solenoid valve or check valve malfunctions during circulating preheating, preventing proper opening and closing, the controller cannot determine if the recirculation system is faulty, hindering troubleshooting. Summary of the Invention

[0003] Therefore, it is necessary to provide a method for detecting recirculation faults, a gas water heater, and a storage medium that can detect recirculation faults, in response to the above-mentioned technical problems.

[0004] Firstly, this application provides a method for detecting a recirculation device malfunction. Applied to a gas water heater, the gas water heater includes a recirculation device, which comprises a hot water pipe fitting, a cold water pipe fitting, a solenoid valve, a check valve, and a temperature sensor. The solenoid valve and the check valve are located between the hot water pipe fitting and the cold water pipe fitting. The solenoid valve is connected to the hot water pipe fitting, and the check valve is connected to the cold water pipe fitting. The solenoid valve is used to shut off or connect the hot water pipe fitting and the cold water pipe fitting, and the check valve is used to connect the hot water pipe fitting and the cold water pipe fitting in one direction. The temperature sensor is located in the communication path between the solenoid valve and the check valve. The method for detecting the recirculation device malfunction includes: acquiring the current water temperature after the gas water heater has completed its preheating cycle; wherein the current water temperature is detected by the temperature sensor; determining the temperature fluctuation range based on the current water temperature; and determining that the recirculation device malfunctions if the temperature fluctuation range is greater than a preset range.

[0005] In one embodiment, the step of determining the temperature fluctuation range based on the current water temperature includes: filtering out the highest and lowest temperatures based on the current water temperature within a preset time period; and determining the temperature fluctuation range based on the highest and lowest temperatures.

[0006] In one embodiment, the step of determining that the water return device is faulty if the temperature fluctuation amplitude is greater than a preset amplitude includes: if the temperature fluctuation amplitude is greater than the preset amplitude and is an increase in temperature, then the solenoid valve is faulty.

[0007] In one embodiment, the step of determining that the water return device is faulty if the temperature fluctuation amplitude is greater than a preset amplitude further includes: determining that the one-way valve is faulty if the temperature fluctuation amplitude is greater than the preset amplitude and is a cooling phenomenon.

[0008] In one embodiment, the method for detecting a water return valve malfunction further includes: controlling the gas water heater to start circulating preheating; obtaining the preheated water temperature; and if the preheated water temperature is greater than a preset temperature, stopping the circulating preheating and closing the solenoid valve.

[0009] In one embodiment, the step of controlling the gas water heater to start circulating preheating includes: starting the water pump and opening the solenoid valve; obtaining the circulating water flow rate; and if the circulating water flow rate is greater than a preset flow rate, igniting the gas to perform preheating.

[0010] In one embodiment, the preheated water temperature is detected by the temperature sensor.

[0011] Secondly, this application also provides a gas water heater. The gas water heater includes: a main controller and a return water device as described in the first aspect embodiment above. The main controller is communicatively connected to the temperature sensor, and the main controller is used to implement the return water device fault detection method described in the first aspect embodiment above.

[0012] In one embodiment, the gas water heater further includes: a heat exchanger, a cold water main pipe, a cold water branch pipe, a hot water outlet pipe, a water pump, and a water flow sensor. The two ends of the cold water branch pipe are respectively connected to the cold water fittings and the cold water main pipe, and the hot water outlet pipe is connected to the hot water fittings. The cold water main pipe, heat exchanger, hot water outlet pipe, return water device, and cold water branch pipe are connected end to end in sequence to form a circulation pipeline. The water pump and the water flow sensor are located on the cold water main pipe, and the main controller is electrically connected to the water pump and the water flow sensor respectively.

[0013] Thirdly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps of the water return device fault detection method described in the first aspect embodiment.

[0014] The aforementioned method for detecting water return device malfunctions, gas water heaters, and storage media uses a temperature sensor installed between the solenoid valve and check valve of the water return device to detect the current water temperature. Since the solenoid valve and check valve are closed after the circulation preheating is completed, the current water temperature between them will not fluctuate significantly. If the detected temperature fluctuation is greater than a preset range, it indicates that the solenoid valve or check valve of the water return device has malfunctioned, thus quickly determining whether the water return device is faulty and facilitating troubleshooting. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a gas water heater in one embodiment;

[0016] Figure 2 This is a three-dimensional schematic diagram of the water return device in one embodiment;

[0017] Figure 3 This is a cross-sectional schematic diagram of the water return device in one embodiment;

[0018] Figure 4 This is a flowchart illustrating a water return device fault detection method in one embodiment;

[0019] Figure 5 This is a flowchart illustrating the process of determining the temperature fluctuation amplitude in one embodiment;

[0020] Figure 6 This is a flowchart illustrating a water return device fault detection method in another embodiment;

[0021] Figure 7 This is a schematic diagram of the process for initiating cyclic preheating in one embodiment;

[0022] Figure 8 Here is a graph showing the change in current temperature under different conditions in one embodiment;

[0023] Explanation of reference numerals in the attached figures:

[0024] Return water device 100, gas water heater body 200, hot water pipe fittings 110, cold water pipe fittings 120, solenoid valve 130, check valve 140, temperature sensor 150, connecting passage 160, main controller 210, heat exchanger 220, cold water main pipe 230, cold water branch pipe 240, hot water outlet pipe 250, water pump 260, water flow sensor 270, water pressure sensor 280, first water point 310, second water point 320. Detailed Implementation

[0025] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0027] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.

[0028] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0029] The water return device fault detection method provided in this application embodiment can be applied to, for example, Figure 1 In the application environment shown, the gas water heater includes a return water unit 100, which includes a hot water pipe fitting 110, a cold water pipe fitting 120, a solenoid valve 130, a check valve 140, and a temperature sensor 150. The solenoid valve 130 and the check valve 140 are located between the hot water pipe fitting 110 and the cold water pipe fitting 120. The solenoid valve 130 is connected to the hot water pipe fitting 110, and the check valve 140 is connected to the cold water pipe fitting 120. The solenoid valve 130 is used to shut off or connect the hot water pipe fitting 110 and the cold water pipe fitting 120, and the check valve 140 is used to connect the hot water pipe fitting 110 and the cold water pipe fitting 120 in one direction. The temperature sensor 150 is located on the communication passage 160 between the solenoid valve 130 and the check valve 140.

[0030] Specifically, the valve chamber of the solenoid valve 130 can be connected to the hot water pipe 110, and the valve core of the solenoid valve 130 controls the opening and closing of the valve chamber of the solenoid valve 130 and the hot water pipe 110. There is a connection passage 160 between the check valve 140 and the solenoid valve 130, and the temperature sensor 150 is set on the connection passage 160. The valve chamber of the check valve 140 can be connected to the cold water pipe 120, and the valve core of the check valve 140 enables one-way connection between the hot water pipe 110 and the cold water pipe 120. When the gas water heater activates its circulating preheating function, both solenoid valve 130 and check valve 140 open. Cold water flows from the cold water main pipe 230 into the heat exchanger 220. The heat exchanger 220 preheats the cold water, causing hot water to flow from the hot water outlet pipe 250 to the hot water fitting 110, then through the connecting passage 160 to the cold water fitting 120, and finally back to the heat exchanger 220 from the cold water branch pipe 240. This circulating water circuit, formed by the return water device 100, completes the preheating of the water flow during circulation. One end of the hot water fitting 110 and the cold water fitting 120 is connected to the first water point 310, from which the user can draw water. It is understood that water points can also be set at other locations in the circulating water circuit, for example... Figure 1 The second water point 320 shown in the figure is connected to the cold water pipe 240 and the hot water outlet pipe 250 respectively.

[0031] In one embodiment, such as Figure 4 As shown, a method for detecting faults in a water return device is provided, which is then applied to... Figure 1 Taking a gas water heater as an example, the explanation includes the following steps:

[0032] Step S410: After the gas water heater completes its preheating cycle, the current water temperature is obtained. Specifically, the current water temperature is detected by the temperature sensor 150. Once the gas water heater completes its preheating cycle, both the solenoid valve 130 and the check valve 140 close. At this time, the water flow in the connecting passage 160 between the solenoid valve 130 and the check valve 140 is isolated from the circulating water path. Simultaneously, the temperature sensor 150 immediately detects the temperature of the water flow in real time, thus obtaining the current water temperature. It can be understood that the current water temperature may include water temperature data over a period of time.

[0033] Step S420: Determine the temperature fluctuation range based on the current water temperature. Specifically, after obtaining the current water temperature, calculate the temperature fluctuation range based on the current water temperature. The temperature fluctuation range is used to indicate the magnitude of the temperature fluctuation; the larger the temperature fluctuation range, the greater the degree of water temperature rise or fall; conversely, the smaller the temperature fluctuation range, the smaller the degree of water temperature rise or fall.

[0034] In step S430, if the temperature fluctuation exceeds a preset range, a fault is identified in the recirculation system. Specifically, after completing the preheating cycle, both solenoid valve 130 and check valve 140 close. The current water temperature is the temperature of the water flow in the connecting passage 160 between solenoid valve 130 and check valve 140. When solenoid valve 130 and check valve 140 are functioning correctly, even if the user uses hot or cold water at the first water point 310, the current water temperature detected by temperature sensor 150 will not be significantly affected, resulting in a small temperature fluctuation. When the temperature fluctuation exceeds the preset range, it indicates significant heat exchange between the water flow in the connecting passage 160 and the circulation pipe, meaning that solenoid valve 130 or check valve 140 is not fully closed. In this case, a fault is identified in the recirculation system 100, and a corresponding fault code is output for the user or maintenance personnel to review. The preset range is a value determined through experimental data; different recirculation systems 100 can use different preset ranges. In one embodiment, the preset range can be set to 2 degrees Celsius.

[0035] The above-mentioned method for detecting water return device malfunctions involves installing a temperature sensor 150 between the solenoid valve 130 and the check valve 140 of the water return device 100 to detect the current water temperature. Since the solenoid valve 130 and the check valve 140 are closed after the circulation preheating is completed, the current water temperature between them will not fluctuate significantly. If the detected temperature fluctuation is greater than the preset range, it indicates that the solenoid valve 130 or the check valve 140 of the water return device 100 has malfunctioned, thus quickly determining whether the water return device 100 has malfunctioned, which facilitates subsequent troubleshooting.

[0036] In one embodiment, such as Figure 5 As shown, step S420, which involves determining the temperature fluctuation range based on the current water temperature, includes:

[0037] Step S421: Filter the highest and lowest temperatures based on the current water temperature within a preset time period. Specifically, filter the highest and lowest temperatures from the temperature data within the preset time period obtained from the current water temperature. For example, if the preset time period is set to 10 seconds after the gas water heater completes its preheating cycle, the current water temperature is the temperature data within these 10 seconds, and then the highest and lowest temperatures are filtered from the current water temperature.

[0038] Step S420: Determine the temperature fluctuation amplitude based on the highest and lowest temperatures. Specifically, the difference between the highest and lowest temperatures can be used as the temperature fluctuation amplitude; in this case, the temperature fluctuation amplitude is always positive. In some other embodiments, the time points at which the highest and lowest temperatures occur can be compared simultaneously, and the temperature value at the later time point can be subtracted from the temperature value at the earlier time point. In this case, the temperature fluctuation amplitude can be negative. Based on the sign of the temperature fluctuation amplitude, the overall trend of water temperature change can be determined.

[0039] In one embodiment, step S430, determining a fault in the recirculation system if the temperature fluctuation exceeds a preset range, includes: if the temperature fluctuation exceeds the preset range and is an upward trend, determining a fault in the solenoid valve. Specifically, if the temperature fluctuation exceeds the preset range, it indicates a fault in the recirculation system 100. At this point, the current water temperature is used to determine whether the temperature fluctuation trend is upward or downward. The temperature fluctuation trend can be determined by the time points of the highest and lowest temperatures, or by comparing the water temperature immediately after the gas water heater completes its preheating cycle with the average water temperature over a preset time period. If the temperature is determined to be rising, it indicates that hot water is being added to the connecting passage 160. In this case, a fault in the solenoid valve 130 causes it to not close properly (e.g., sand at the valve port, disconnected wires, etc.). The hot water being used by the user flows through the hot water pipe 110 into the connecting passage 160 and is detected by the temperature sensor 150. After determining that the solenoid valve 130 is faulty, a corresponding fault code for the solenoid valve 130 is output for the user and maintenance personnel to review, facilitating subsequent troubleshooting.

[0040] In one embodiment, step S430, which determines that the return water device is faulty if the temperature fluctuation amplitude is greater than a preset amplitude, further includes: if the temperature fluctuation amplitude is greater than the preset amplitude and the temperature is decreasing, then the check valve is faulty. Specifically, if the temperature fluctuation amplitude is greater than the preset amplitude, it indicates that the return water device 100 is faulty. If the temperature is decreasing, it indicates that cold water is being supplied to the connecting passage 160. At this time, if the check valve 140 is faulty and fails to close properly (e.g., due to sand or gravel at the valve port, mechanical failure, etc.), the cold water being used by the user flows through the cold water pipe 120 into the connecting passage 160 and is detected by the temperature sensor 150. After determining that the check valve 140 is faulty, a corresponding check valve 140 fault code is output for the user and maintenance personnel to view, facilitating subsequent troubleshooting. It is understood that when both the solenoid valve 130 and the check valve 140 are faulty, the faultiness of the solenoid valve 130 or the check valve 140 can be detected separately by using hot or cold water at the water point.

[0041] In one embodiment, such as Figure 6 As shown, the method for detecting water return device malfunctions also includes:

[0042] Step S510: Control the gas water heater to start circulating preheating;

[0043] Step S520: Obtain the preheated water temperature;

[0044] In step S530, if the preheated water temperature is higher than the preset temperature, stop the circulating preheating and close the solenoid valve.

[0045] Specifically, when the user controls the gas water heater to start circulating preheating via command, the solenoid valve 130 and the one-way valve 140 will open, and the water in the circulating water circuit will circulate and be heated. At this time, it is necessary to detect the water temperature in the circulating water circuit to obtain the preheated water temperature. In one embodiment, the preheated water temperature is detected by the temperature sensor 150. By using the temperature sensor 150, the current water temperature and the preheated water temperature can be detected, reducing the number of temperature detection devices. In some other embodiments, temperature detection devices can also be set at other locations in the circulating water circuit to detect the preheated water temperature. When the detected preheated water temperature is greater than the preset temperature, it indicates that the water temperature in the circulating water circuit has reached the preheating requirement. At this time, circulating preheating is stopped and the solenoid valve 130 is closed. Correspondingly, when the solenoid valve 130 is closed, the one-way valve 140 will also close.

[0046] In one embodiment, such as Figure 7 As shown, step S510, the step of controlling the gas water heater to start the circulation preheating, includes:

[0047] Step S511: Start the water pump and open the solenoid valve;

[0048] Step S512: Obtain the circulating water flow rate;

[0049] Step S513: If the circulating water flow rate is greater than the preset flow rate, then ignite to preheat.

[0050] Specifically, when controlling the gas water heater to start circulating preheating, the water pump 260 is first started and the solenoid valve 130 is opened. The water pump 260 is used to drive the water flow in the circulating water circuit to circulate. The water pump 260 can be set between the water inlet of the gas water heater body 200 and the heat exchanger 220, or at any position in the circulating water circuit, to detect the water flow rate in the circulating water circuit, thereby obtaining the circulating water flow rate. To prevent insufficient water flow to the heat exchanger 220 from resulting in low heat exchange efficiency, ignition is controlled only when the detected circulating water flow rate is greater than the preset flow rate to preheat the circulating water. In some embodiments, the preset flow rate can be set to 3 liters per minute.

[0051] The detection principle of the water return device fault detection method of this application is described in detail below with a specific embodiment. For example... Figure 8The figure shows the temperature change curves detected when the solenoid valve 130 is in different states, with the hot water and cold water ends open. When the solenoid valve 130 is normally closed, the check valve 140 is also normally closed. At this time, opening either the cold water or hot water end of the first water intake point results in a slow temperature decrease because there is no flow exchange at the connecting passage 160. Simultaneously, due to heat conduction through the return water device 100, the temperature decreases faster when the cold water end is open. However, within 10 seconds after the preheating cycle is complete, the temperature fluctuation is less than 1 degree Celsius in both cases. When the solenoid valve 130 malfunctions and fails to close properly, opening either the cold water or hot water end of the first water intake point causes flow exchange with the hot water at the connecting passage 160. This causes the temperature to fluctuate and rise. Furthermore, with the hot water end open, the flow exchange is more frequent, resulting in a faster temperature rise. However, within 10 seconds after the preheating cycle is complete, the temperature fluctuation is greater than 1.5 degrees Celsius in both cases. At this point, setting the preset range to between 1 and 1.5 degrees Celsius will allow us to determine if solenoid valve 130 is faulty. Similarly, when check valve 140 malfunctions, the temperature drop will be greater, thus allowing us to determine if check valve 140 is faulty.

[0052] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0053] Based on the same inventive concept, this application also provides a gas water heater for implementing the above-mentioned method for detecting a recirculating water heater malfunction. The solution provided by this gas water heater is similar to the solution described in the above method; therefore, the specific limitations in one or more gas water heater embodiments provided below can be found in the limitations of the recirculating water heater malfunction detection method described above, and will not be repeated here.

[0054] In one embodiment, such as Figures 1 to 3As shown, a gas water heater is provided, which includes a main controller 210 and a return water device 100 in the above embodiment. The main controller 210 is communicatively connected to a temperature sensor 150 and is used to implement the return water device fault detection method in the above embodiment.

[0055] In one embodiment, the gas water heater further includes: a heat exchanger 220, a cold water main pipe 230, a cold water branch pipe 240, a hot water outlet pipe 250, a water pump 260, and a water flow sensor 270. The two ends of the cold water branch pipe 240 are respectively connected to the cold water fitting 120 and the cold water main pipe 230, and the hot water outlet pipe 250 is connected to the hot water fitting 110. The cold water main pipe 230, the heat exchanger 220, the hot water outlet pipe 250, the return water device 100, and the cold water branch pipe 240 are connected end to end in sequence to form a circulation pipeline. The water pump 260 and the water flow sensor 270 are located in the cold water main pipe 230, and the main controller 210 is electrically connected to the water pump 260 and the water flow sensor 270 respectively.

[0056] When the gas water heater activates its circulating preheating function, both solenoid valve 130 and check valve 140 open. Cold water flows from the cold water main pipe 230 into the heat exchanger 220. The heat exchanger 220 preheats the cold water, causing hot water to flow from the hot water outlet pipe 250 to the hot water fitting 110, then through the connecting passage 160 to the cold water fitting 120, and finally back to the heat exchanger 220 from the cold water branch pipe 240. This circulating pipeline, formed by the return water device 100, completes the preheating of the water in the pipeline during the circulation process. One end of the hot water fitting 110 and the cold water fitting 120 is connected to the first water point 310, from which the user can draw water. It is understood that water points can also be set at other locations in the circulating water circuit, for example... Figure 1 The second water point 320 shown in the figure is connected to the cold water pipe 240 and the hot water outlet pipe 250 respectively.

[0057] In one embodiment, such as Figure 1 As shown, the gas water heater also includes a water pressure sensor 280, which is connected to the main controller 210. Specifically, the main controller 210 uses the water pressure sensor 280 to detect whether the water pressure in the cold water main pipe 230 is normal, and adjusts the speed of the water pump 260 accordingly.

[0058] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described embodiment of the water return device fault detection method.

[0059] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting a recirculation device malfunction, applied in a gas water heater, characterized in that, The gas water heater includes a return water device (100), which includes a hot water pipe fitting (110), a cold water pipe fitting (120), a solenoid valve (130), a check valve (140), and a temperature sensor (150). The solenoid valve (130) and the check valve (140) are located between the hot water pipe fitting (110) and the cold water pipe fitting (120). The solenoid valve (130) is connected to the hot water pipe fitting (110), and the check valve (140) is connected to the cold water pipe fitting (120). The solenoid valve (130) is used to shut off or connect the hot water pipe fitting (110) and the cold water pipe fitting (120), and the check valve (140) is used to connect the hot water pipe fitting (110) and the cold water pipe fitting (120) in one direction. The temperature sensor (150) is located on the communication passage (160) between the solenoid valve (130) and the check valve (140). The method for detecting water return device malfunctions includes: When the gas water heater has completed the preheating cycle, the current water temperature is obtained; wherein the current water temperature is detected by the temperature sensor (150); The temperature fluctuation range is determined based on the current water temperature. If the temperature fluctuation is greater than the preset range, it is determined that the water return device (100) is faulty.

2. The method for detecting water return device malfunctions according to claim 1, characterized in that, The step of determining the temperature fluctuation range based on the current water temperature includes: Based on the current water temperature within a preset time period, the highest and lowest temperatures are selected. The temperature fluctuation range is determined based on the highest temperature and the lowest temperature.

3. The method for detecting water return device malfunctions according to claim 1, characterized in that, The step of determining that the water return device (100) is faulty if the temperature fluctuation amplitude is greater than a preset amplitude includes: If the temperature fluctuation is greater than the preset range and is an increase, then the solenoid valve (130) is determined to be faulty.

4. The method for detecting water return device malfunctions according to claim 1, characterized in that, The step of determining that the water return device (100) is faulty if the temperature fluctuation amplitude is greater than a preset amplitude further includes: If the temperature fluctuation is greater than the preset range and is a cooling phenomenon, then the one-way valve (140) is determined to be faulty.

5. The method for detecting a water return device malfunction according to any one of claims 1 to 4, characterized in that, The method further includes: Control the gas water heater to start circulating preheating; Obtain the preheated water temperature; If the preheated water temperature is higher than the preset temperature, then stop the circulating preheating and close the solenoid valve (130).

6. The method for detecting a water return device malfunction according to claim 5, characterized in that, The step of controlling the gas water heater to start the circulation preheating includes: Start the water pump (260) and open the solenoid valve (130); Obtain the circulating water flow rate; If the circulating water flow rate is greater than the preset flow rate, then ignition is performed for preheating.

7. The method for detecting water return device faults according to claim 5, characterized in that, The temperature of the preheated water is detected by the temperature sensor (150).

8. A gas water heater, characterized in that, The gas water heater includes: a main controller (210) and a return water device (100) as described in any one of claims 1 to 7, wherein the main controller (210) is communicatively connected to the temperature sensor (150), and the main controller (210) is used to implement the return water device fault detection method as described in any one of claims 1 to 7.

9. The gas water heater according to claim 8, characterized in that, The gas water heater also includes: a heat exchanger (220), a cold water main pipe (230), a cold water branch pipe (240), a hot water outlet pipe (250), a water pump (260), and a water flow sensor (270). The two ends of the cold water branch pipe (240) are respectively connected to the cold water fitting (120) and the cold water main pipe (230), and the hot water outlet pipe (250) is connected to the hot water fitting (110). The cold water main pipe (230), the heat exchanger (220), the hot water outlet pipe (250), the return water device (100), and the cold water branch pipe (240) are connected end to end in sequence to form a circulation pipeline. The water pump (260) and the water flow sensor (270) are located in the cold water main pipe (230). The main controller (210) is electrically connected to the water pump (260) and the water flow sensor (270).

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the water return device fault detection method according to any one of claims 1 to 7.

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