A detection system and control method for detecting zero cold water performance of water heater

Abstract

The present invention discloses a detection system and control method for detecting the zero cold water performance of a water heater. The detection system includes at least one detection device, a timing device and a control device. The detection device is installed on the circulation pipeline of the water heater and forms a test point. It includes a temperature detection unit for detecting the water temperature value of the test point and a water flow switch unit for controlling the water flow interruption of the test point. The timing device is used to record the water temperature stabilization time of the test point. The control device is electrically connected to the temperature detection unit, the water flow switch unit and the timing device respectively. The detection system of the present invention can fully automatically test the water temperature stabilization time and water temperature fluctuation index of the water heater by installing at least one detection device on the circulation pipeline of the water heater, and by cooperating with the detection device, the timing device and the control device, thereby realizing the zero cold water performance of the water heater with high accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of water heaters, and in particular to a detection technology for zero cold water performance of a water heater. Background Art

[0002] Existing zero-cold-water gas water heaters are all constant-temperature gas water heaters. When the user activates the instant hot button, the water pump starts working. The gas water heater detects the water flow signal and first turns on the fan for pre-cleaning to discharge the exhaust gas in the water heater through the smoke pipe. After the wind pressure switch detects that it is closed, the air valve is opened and ignited. The water is heated by the water pump in the pipeline and then flows out through the water heater. There are many links from the user turning on the water to the constant-temperature hot water flowing out. The time required for different water heaters varies. In addition, due to the influence of different lengths of pipelines, the temperature fluctuation will also vary greatly. The different designs of the internal structure of the water heater and the related control algorithms will have a great impact on this.

[0003] When testing zero-cold-water gas water heaters, the important parameters related to the above-mentioned links are not fully tested. Most of them are simple manual tests with poor test consistency and accuracy. Summary of the invention

[0004] The present invention aims to solve at least one of the problems existing in the existing related technologies to a certain extent. To this end, the present invention proposes a detection system for detecting the zero cold water performance of a water heater, which can automatically test the water temperature stabilization time and water temperature fluctuation index of the water heater, thereby realizing the zero cold water performance of the water heater with high accuracy.

[0005] The invention also provides a control method for the detection system.

[0006] According to the above-mentioned detection system for detecting the zero cold water performance of a water heater, it is implemented through the following technical solutions:

[0007] A detection system for detecting the zero cold water performance of a water heater, comprising: at least one detection device, the detection device is installed on the water heater circulation pipeline to form a test point, and the detection device includes a temperature detection unit and a water flow switch unit, the temperature detection unit is used to detect the water temperature value of the test point, and the water flow switch unit is used to control the water flow interruption of the test point; a timing device, used to record the water temperature stabilization time of the test point; a control device, the control device is electrically connected to the temperature detection unit, the water flow switch unit and the timing device respectively, and the control device is used to obtain a water temperature fluctuation value according to the detected water temperature value, and is also used to determine the zero cold water performance of the water heater according to the water temperature fluctuation value and the water temperature stabilization time.

[0008] In some embodiments, the detection device further includes a water flow detection unit for detecting a water flow value at a test point, and the water flow detection unit is electrically connected to the control device.

[0009] In some embodiments, an exhaust device and / or a water regulating device are further included. The exhaust device is installed on the circulation pipeline of the water heater and is electrically connected to the control device. The water regulating device is installed at the water inlet of the water heater and is electrically connected to the control device.

[0010] In some embodiments, a display device is further included, and the display device is electrically connected to the control device.

[0011] In some embodiments, the number of the detection devices is four, and the four detection devices are installed at different positions of the water heater circulation pipeline to form four test points.

[0012] According to the control method of a detection system provided above, it is implemented through the following technical solutions:

[0013] A control method of a detection system, which uses the detection system for detecting the zero cold water performance of a water heater as described above, and the control method comprises the following steps:

[0014] S1: Exhaust excess air in the water heater circulation pipeline;

[0015] S2: Control the water heater to start the instant heating mode;

[0016] S3: Determine whether the instant heating of the water heater is completed, if yes, proceed to the next step, if not, continue to execute this step;

[0017] S4: Turn on the water flow switch unit of the first test point, start recording the water temperature stabilization time t1 of the first test point, and obtain the water temperature fluctuation value △T1 of the first test point;

[0018] S5: Determine the zero cold water performance of the water heater according to the water temperature stabilization time t1 and the water temperature fluctuation value △T1 of the first test point.

[0019] In some implementations, obtaining the water temperature fluctuation value ΔT1 at the first test point specifically includes:

[0020] S41: After the water flow switch unit is turned on for a period of time, the water temperature value is collected once at a preset time interval, and the collection is performed N times to obtain a temperature data group;

[0021] S42: extracting the maximum value and the minimum value from the temperature data group;

[0022] S43: Calculate the water temperature fluctuation value △T1 of the first test point according to the maximum value and the minimum value.

[0023] In some implementations, while obtaining the water temperature fluctuation value ΔT1 of the first test point, a water flow data set of the test point is first obtained through a water flow detection unit, and then an average water flow value Q1 is calculated based on the obtained water flow data set.

[0024] In some embodiments, in step S5, determining the zero cold water performance of the water heater according to the water temperature stabilization time t1 and the water temperature fluctuation value ΔT1 of the first test point specifically includes:

[0025] S51: Determine whether the water temperature stabilization time t1 is greater than a reference value, and determine whether the water temperature fluctuation value △T1 is greater than a temperature threshold;

[0026] S52: If the water temperature stabilization time t1 ≤ the reference value and the water temperature fluctuation value △T1 ≤ the temperature threshold, it is determined that the zero cold water performance of the water heater is qualified;

[0027] S53: If the water temperature stabilization time t1>reference value and / or the water temperature fluctuation value ΔT1>temperature threshold, it is determined that the zero cold water performance of the water heater is unqualified.

[0028] In some embodiments, the control method further comprises the following steps:

[0029] S6: Repeat steps S1 to S3;

[0030] S7: when the instant heating of the water heater is completed, the water flow switch unit of the second test point is turned on, the water temperature stabilization time t2 of the second test point is recorded, and the water temperature fluctuation value △T2 of the second test point is obtained;

[0031] S8: Determine the zero cold water performance of the water heater based on the water temperature stabilization time t2 and the water temperature fluctuation value △T2 of the second test point.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] 1. The detection system of the present invention can automatically test the zero cold water performance of the water heater by installing at least one detection device on the circulation pipeline of the water heater and forming at least one test point, and by cooperating with the detection device, the timing device and the control device;

[0034] 2. The control device can determine the zero cold water performance of the water heater according to the obtained water temperature fluctuation value and water temperature stabilization time, thereby realizing the fully automatic testing of the water temperature stabilization time and water temperature fluctuation index of the water heater, and then realizing the zero cold water performance of the water heater with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a connection block diagram of the detection system in Embodiment 1 of the present invention;

[0036] Figure 2 is a schematic diagram of the structure in which the detection system in Embodiment 1 of the present invention is installed on the circulation pipeline of the water heater;

[0037] Figure 3 is a flow chart of a control method of a detection system in Embodiment 2 of the present invention;

[0038] Figure 4 is the sub-flowchart in step S4;

[0039] Figure 5 is the sub-flow chart in step S5;

[0040] Figure 6 It is a flow chart of the control method of the detection system in Example 3 of the present invention. DETAILED DESCRIPTION

[0041] The following examples illustrate the present invention, but the present invention is not limited by these examples. Modifications to the specific embodiments of the present invention or equivalent replacement of some technical features without departing from the spirit of the present invention should be included in the scope of the technical solution claimed by the present invention.

[0042] Example 1

[0043] See also Figure 1-2 The present embodiment provides a detection system for detecting the zero cold water performance of a water heater, comprising at least one detection device 1, a timing device 2 and a control device 3, wherein the detection device 1 is installed on a water heater circulation pipeline (not shown in the figure) and forms a test point, and the detection device 1 comprises a temperature detection unit 11 and a water flow switch unit 12, the temperature detection unit 11 is used to detect the water temperature value of the test point, and the water flow switch unit 12 is used to control the water flow interruption of the test point. The timing device 2 is used to record the water temperature stabilization time of the test point. The control device 3 is electrically connected to the temperature detection unit 11, the water flow switch unit 12 and the timing device 2 respectively, and the control device 3 is used to obtain the water temperature fluctuation value according to the detected water temperature value, and is also used to determine the zero cold water performance of the water heater according to the water temperature fluctuation value and the water temperature stabilization time. In addition, the control device 3 can also be electrically connected to the controller of the water heater to realize the control of the working state of the water heater through the control device 3. In the present embodiment, the electrical connection includes an electrical connection and a communication connection, wherein the communication connection includes a wireless communication connection and a wired communication connection.

[0044] It can be seen that the detection system of this embodiment can realize automatic testing of the zero cold water performance of the water heater by installing at least one detection device 1 on the circulation pipeline of the water heater and forming at least one test point, and by cooperating with the detection device 1, the timing device 2 and the control device 3. In addition, the control device 3 can determine the zero cold water performance of the water heater according to the obtained water temperature fluctuation value and the water temperature stabilization time, and realize the full-automatic testing of the water temperature stabilization time and water temperature fluctuation index of the water heater, thereby realizing the zero cold water performance of the water heater with high accuracy.

[0045] Preferably, the detection device 1 also includes a water flow detection unit 13, which is electrically connected to the control device 3 and is used to detect the water flow value of the test point. The control device 3 can calculate the average water flow value of the test point based on multiple water flow values, thereby accurately detecting the water flow size of the test point.

[0046] See also Figure 2 Specifically, the water heater is a zero-cold-water gas water heater, which includes an internal pipeline 70, a water inlet 71, a hot water outlet 72, a water inlet temperature probe 73, a water outlet temperature probe 74, a circulation pump 75 and a controller (not shown in the figure), wherein the two ends of the internal pipeline 70 are respectively connected to the water inlet 71 and the hot water outlet 72, the water inlet temperature probe 73 and the water outlet temperature probe 74 are respectively installed on the water inlet section and the water outlet section of the internal pipeline 70, the circulation pump 75 is installed on the water inlet section of the internal pipeline 70, and the controller is respectively electrically connected to the water inlet temperature probe 73, the water outlet temperature probe 74 and the circulation pump 75. Specifically, the water heater circulation pipeline is composed of an external hot water pipe 81, a return pipe 82 and an external cold water pipe 83, one end of the external hot water pipe 81 is connected to the hot water outlet 72, and the other end is connected to the external cold water pipe 83 through the return pipe 82, and the end of the external cold water pipe 83 away from the return pipe 82 is connected to the water inlet 71.

[0047] See also Figure 1-2 , further, it also includes an exhaust device 4 and a water regulating device 5. The exhaust device 4 is installed on the water heater circulation pipeline and electrically connected to the control device 3, and can be used to remove excess air in the water heater circulation pipeline. In this way, it can avoid the air in the circulation pipeline from interfering with the test results, making the test accuracy of the zero cold water performance of the water heater higher. The water regulating device 5 is installed at the water inlet of the water heater and electrically connected to the control device 3, and is used to adjust the water inlet flow rate of the water heater. In this way, the water inlet flow rate of the water heater can be adjusted according to actual needs through the water regulating device 5, so that the water temperature stabilization time and water temperature fluctuation performance indicators can be tested separately under different environments (different water flow rates, etc.), thereby improving the adaptability of the detection system.

[0048] In this embodiment, the water regulating device 5 is installed at the water inlet 71 of the water heater, and the exhaust device 4 is installed on the external cold water pipe 83 and close to the water regulating device 5. In other embodiments, the exhaust device 4 or the water regulating device 5 can be omitted, so that the overall structure of the detection system is simpler and the cost is lower.

[0049] Furthermore, a display device 6 is also included, and the display device 6 is electrically connected to the control device 3. Preferably, the display device 6 of this embodiment is a PC computer that is connected to the control device 3 for communication, and is used to output and store test data, so as to facilitate later viewing of all test data, such as water temperature fluctuation value, average water flow rate and water temperature stabilization time.

[0050] See also Figure 2 Preferably, the number of detection devices 1 is four, and the four detection devices 1 are installed at different positions of the water heater circulation pipeline to form four test points. Each detection device 1 includes a temperature detection unit 11, a water flow switch unit 12 and a water flow detection unit 13, which are respectively electrically connected to the control device 3. Specifically, the first detection device 1 is installed on the external hot water pipe 81, approximately located at a position where the external hot water pipe 81 is ten meters away from the hot water outlet 72. The second detection device 1 is installed on the return pipe 82, and the pipeline spacing between the second detection device 1 and the first detection device 1 is about 10 meters. The third detection device 1 is installed on the external cold water pipe 83, and the pipeline spacing between the third detection device 1 and the second detection device 1 is about 10 meters. The fourth detection device 1 is installed on the external cold water pipe 83 and close to the water inlet 71. As a result, the four detection devices 1 are respectively located at different positions of the water heater circulation pipeline and form four test points, so that multi-point and multiple repeated tests can be performed, with higher accuracy, which can be applied to different usage scenarios.

[0051] Example 2

[0052] See also Figure 3 This embodiment provides a control method for a detection system, which uses a detection system for detecting the zero cold water performance of a water heater described in Example 1. The control method includes the following steps:

[0053] S1: Exhaust excess air in the water heater circulation pipeline;

[0054] Specifically, the excess air can be discharged by opening the exhaust device 4, or by opening the water flow switch unit 12 at the fourth test point. This embodiment takes the discharge of excess air through the water flow switch unit 12 at the fourth test point as an example. After the water heater to be tested is correctly connected to gas, electricity and water, the detection system is installed on the water heater circulation pipeline; after power is connected, the water flow switch unit 12 at the fourth test point is controlled to open to discharge the excess air in the pipeline, and after 3 minutes, the water flow switch unit 12 at the fourth test point is controlled to close.

[0055] S2: Control the water heater to start the instant heating mode;

[0056] Specifically, the water heater is controlled to start the instant heating mode through the controller or control device 3 of the water heater, so that the water heater enters the instant heating control mode.

[0057] S3: Determine whether the instant heating of the water heater is completed, if yes, proceed to the next step, if not, continue to execute this step;

[0058] S4: Turn on the water flow switch unit 12 of the first test point, start recording the water temperature stabilization time t1 of the first test point, and obtain the water temperature fluctuation value △T1 of the first test point;

[0059] Specifically, one of the four test points is selected as the first test point. For ease of understanding, this embodiment takes the test point close to the hot water outlet 72 of the water heater as the first test point, and so on according to the direction of water flow. The test point farthest from the hot water outlet 72 of the water heater (i.e., close to the water inlet 71 of the water heater) is the last test point.

[0060] In this embodiment, the test point near the hot water outlet 72 of the water heater is taken as the first test point as an example. The control device 3 controls the water flow switch unit 12 of the first test point to open, and hot water will flow out of the water flow switch unit 12. At the same time, the timing device 2 starts to record the water temperature stabilization time t1 of the first test point, and the control device 3 obtains the water temperature fluctuation value △T1 of the first test point through the temperature detection unit 11.

[0061] S5: Determine the zero cold water performance of the water heater according to the water temperature stabilization time t1 and the water temperature fluctuation value △T1 of the first test point.

[0062] It can be seen that the control method of the detection system of this embodiment obtains the water temperature stabilization time t1 and the water temperature fluctuation value △T1 of the first test point after the water heater completes instant heating, and determines the zero cold water performance of the water heater based on the obtained water temperature stabilization time t1 and water temperature fluctuation value △T1, thereby realizing fully automatic testing of important indicators such as the water temperature fluctuation value and water temperature stabilization time of the user's water outlet, and further accurately testing the qualification of the zero cold water performance of the water heater.

[0063] Preferably, the water temperature stabilization time t1 is the time from when the water flow switch unit 12 of the first test point is turned on to when the water temperature value of the first test point reaches a stable value. The smaller the water temperature stabilization time t1 is, the better the performance is. If the time is longer, it is more correlated with the constant temperature control after boiling water. It is necessary to appropriately improve the constant temperature control after boiling water to ensure the rapid constant temperature effect of the water heater. Specifically, the temperature detection unit 11 detects the real-time temperature of the water flow at the first test point in real time and feeds it back to the control device 3. When the control device 3 determines that the real-time temperature of the water flow at the first test point is stable within the range of [T setting -1, T setting +1], the water temperature stabilization time t1 of the test point is stored, and the stored water temperature stabilization time t1 is compared with the reference value. Based on the comparison result, the water temperature stabilization time performance of the test point is determined, and finally a report is output through the control display device 6.

[0064] See also Figure 4 Preferably, in step S4, obtaining the water temperature fluctuation value ΔT1 of the first test point specifically includes:

[0065] S41: After the water flow switch unit 12 is turned on for a period of time, water temperature values ​​are collected once, and the collection is performed N times to obtain a temperature data set;

[0066] Specifically, when the water flow switch unit 12 of the first test point is turned on, the water is turned on at the first test point. After 10s of the water being turned on at the first test point, the water temperature value is collected once, and the collection is performed N times to obtain a temperature data set. The collection of the water temperature value once specifically includes: collecting the temperature once at a preset time interval (for example, 100ms) and recording them as a[0], a[1], ..., a[9] respectively, removing the maximum value and the minimum value, and obtaining an average value T[0] within 1s. The average value T[0] is the water temperature value to be collected. In this way, the water temperature value collected each time can be guaranteed to be more accurate, thereby improving the accuracy of the collected data. The temperature data set is obtained by collecting 100 times, and the temperature data set is composed of T[0], T[1], ..., T

[99] .

[0067] S42: extracting the maximum value and the minimum value from the temperature data group;

[0068] Specifically, the maximum and minimum values ​​are extracted from T[0], T[1], ..., T

[99] .

[0069] S43: Calculate the water temperature fluctuation value △T1 of the first test point according to the maximum value and the minimum value.

[0070] Specifically, according to the extracted maximum and minimum values, the water temperature fluctuation value △T1 of the first test point is calculated by the formula: temperature fluctuation value △T=maximum value-minimum value. Thus, the water temperature fluctuation value △T1 of the test point can be accurately tested.

[0071] Preferably, while obtaining the water temperature fluctuation value △T1 of the first test point, the water flow data group of the test point is first obtained through the water flow detection unit 13, and then the average water flow value Q1 is calculated based on the obtained water flow data group. Specifically, the water flow data group of the test point is obtained through the water flow detection unit 13, which specifically includes: after the water is turned on at the first test point for 10s, the water flow is collected every 100ms and counted as L[0], L[1], ..., L[9] respectively, the maximum value and the minimum value are removed, and the average value Q[0] is calculated, that is, a water flow data is obtained within 1s, so that the water flow data collected each time can be more accurate and the accuracy of the collected data can be improved; the water flow data group of the test point is obtained by recording 100 times, and the water flow data group consists of Q[0], Q[1], ..., Q

[99] .

[0072] In addition, the average water flow value Q1 is calculated based on the acquired water flow data group, which is specifically: the maximum water flow value and the minimum water flow value are eliminated from the water flow data group, that is, from Q[0], Q[1], ..., Q

[99] , and the average water flow value Q1 of the first test point is calculated by the averaging formula. In this way, by first eliminating the maximum water flow value and the minimum water flow value in the water flow data group, and then calculating the average value of the remaining data, the calculated average water flow value Q1 is more accurate.

[0073] See also Figure 5 Preferably, in step S5, the step of determining the zero cold water performance of the water heater according to the water temperature stabilization time t1 and the water temperature fluctuation value ΔT1 of the first test point specifically includes:

[0074] S51: Determine whether the water temperature stabilization time t1 is greater than a reference value, and determine whether the water temperature fluctuation value △T1 is greater than a temperature threshold;

[0075] S52: If the water temperature stabilization time t1 ≤ the reference value and the water temperature fluctuation value △T1 ≤ the temperature threshold, it is determined that the zero cold water performance of the water heater is qualified;

[0076] Specifically, the reference value is 30s. If the water temperature stabilization time t1 is less than 30s and greater than 20s, it indicates that the water temperature stabilization time is good; if the water temperature stabilization time t1 is less than 20s, it indicates that the water temperature stabilization time is excellent. The temperature threshold is 4°C. When the water flow rate at the first test point is the average water flow rate value Q1, if the water temperature fluctuation value △T1≤4°C, it indicates that the water temperature fluctuation value index is qualified. When both the water temperature stabilization time and the water temperature fluctuation value meet the standards, it can be determined that the zero cold water performance of the water heater is qualified, ensuring that the first test point can meet the user's comfortable water use requirements. In addition, based on the test results of the first test point, the display device 6 outputs a report to facilitate understanding and review of the test results based on the report content.

[0077] S53: If the water temperature stabilization time t1>reference value and / or the water temperature fluctuation value ΔT1>temperature threshold, it is determined that the zero cold water performance of the water heater is unqualified.

[0078] Specifically, if the water temperature stabilization time t1>30s, it indicates that the water temperature stabilization time performance is average. When the water flow rate at the first test point is the average water flow rate value Q1, if the water temperature fluctuation value △T1>4°C, it indicates that the water temperature fluctuation value index is unqualified. Since the longer the pipeline, the more heat is dissipated, it can be determined that the circulating pipeline behind the first test point will also have a water temperature fluctuation value lower than 4°C. If the user uses water in the circulating pipeline behind the first test point, the circulation heating time needs to be appropriately extended to ensure that the temperature at the water point can meet the user's water demand.

[0079] Example 3

[0080] See also Figure 6 The difference between this embodiment and embodiment 2 is that the control method further includes the following steps:

[0081] S6: Repeat steps S1 to S3;

[0082] Specifically, after or at the same time as the test of the water temperature stabilization time t1 and the water temperature fluctuation value ΔT1 of the first test point is completed, the control device 3 controls the water flow switch unit 12 of the first test point to be closed, and resets the timing of the timing device 2. Then, steps S1 to S3 are repeated to test the water temperature stabilization time and water temperature fluctuation value of the next test point.

[0083] S7: when the instant heating of the water heater is completed, the water flow switch unit 12 of the second test point is turned on, the water temperature stabilization time t2 of the second test point is recorded, and the water temperature fluctuation value ΔT2 of the second test point is obtained;

[0084] S8: Determine the zero cold water performance of the water heater based on the water temperature stabilization time t2 and the water temperature fluctuation value △T2 of the second test point.

[0085] It can be seen that this embodiment tests the water temperature stabilization time t2 and the water temperature fluctuation value △T2 at the second test point, thereby realizing fully automatic testing of important indicators such as the water temperature fluctuation value and the water temperature stabilization time of the water outlets of pipes of different lengths. Multi-point and multiple repeated tests have higher accuracy.

[0086] Furthermore, when detecting the temperature fluctuation value and temperature stabilization time of the third test point, first repeat steps S1 to S3, and then when the instant heating of the water heater is completed, turn on the water flow switch unit 12 of the third test point to automatically detect the temperature fluctuation value △T3 and temperature stabilization time t3 of the third test point. When the temperature fluctuation value △T3 is greater than 4°C, since the shorter the pipeline, the less heat is dissipated, it can be determined that the water temperature fluctuation value of the circulation pipeline before the third test point will also be lower than 4°C. If the user uses water in the circulation pipeline before the third test point, the circulation heating time needs to be appropriately reduced to avoid excessive water temperature and scalding the user.

[0087] In this embodiment, if the test results of the three test points are all qualified or meet the standards, it indicates that the zero cold water performance of the water heater is qualified, and the comfortable water use needs of the user's water outlets with different lengths of pipes can be guaranteed; if at least one or two of the test results of the three test points are unqualified or do not meet the standards, it indicates that the zero cold water performance of the water heater is unqualified, and the relevant control algorithm or internal structure of the water heater needs to be adjusted.

[0088] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A control method for a water heater zero cold water performance detection system, characterized in that: The detection system comprises: At least one detection device (1), the detection device (1) being installed on a circulation pipeline of a water heater and forming a test point, and the detection device (1) comprising a temperature detection unit (11) and a water flow switch unit (12), the temperature detection unit (11) being used to detect a water temperature value at the test point, and the water flow switch unit (12) being used to control the water flow at the test point; A timing device (2) for recording the stabilization time of the water temperature at the test point; A control device (3), the control device (3) being electrically connected to the temperature detection unit (11), the water flow switch unit (12) and the timing device (2), respectively, the control device (3) being used to obtain a water temperature fluctuation value according to the detected water temperature value, and also being used to determine the zero cold water performance of the water heater according to the water temperature fluctuation value and the water temperature stabilization time; The control method comprises the following steps: S1: Exhaust excess air in the water heater circulation pipeline; S2: Control the water heater to start the instant heating mode; S3: Determine whether the instant heating of the water heater is completed, if yes, proceed to the next step, if not, continue to execute this step; S4: turning on the water flow switch unit (12) of the first test point, starting to record the water temperature stabilization time t1 of the first test point, and obtaining the water temperature fluctuation value △T1 of the first test point; S5: Determine the zero cold water performance of the water heater according to the water temperature stabilization time t1 and the water temperature fluctuation value △T1 of the first test point. The specific steps include: S51: Determine whether the water temperature stabilization time t1 is greater than a reference value, and determine whether the water temperature fluctuation value △T1 is greater than a temperature threshold; S52: If the water temperature stabilization time t1 ≤ the reference value and the water temperature fluctuation value △T1 ≤ the temperature threshold, it is determined that the zero cold water performance of the water heater is qualified; S53: If the water temperature stabilization time t1>reference value and / or the water temperature fluctuation value ΔT1>temperature threshold, it is determined that the zero cold water performance of the water heater is unqualified.

2. The control method of a water heater zero cold water performance detection system according to claim 1, characterized in that: The detection device (1) further comprises a water flow detection unit (13) for detecting a water flow value at a test point, wherein the water flow detection unit (13) is electrically connected to the control device (3).

3. The control method of a water heater zero cold water performance detection system according to claim 1, characterized in that: It also comprises an exhaust device (4) and / or a water regulating device (5), wherein the exhaust device (4) is installed on the circulation pipeline of the water heater and is electrically connected to the control device (3), and the water regulating device (5) is installed at the water inlet of the water heater and is electrically connected to the control device (3).

4. The control method of a water heater zero cold water performance detection system according to claim 1, characterized in that: It also includes a display device (6), wherein the display device (6) is electrically connected to the control device (3).

5. A control method for a water heater zero cold water performance detection system according to any one of claims 1 to 4, characterized in that: The number of the detection devices (1) is four, and the four detection devices (1) are installed at different positions of the water heater circulation pipeline to form four test points.

6. A control method for a water heater zero cold water performance detection system according to claim 5, characterized in that: The water heater comprises an internal pipeline (70), a water inlet (71) and a hot water outlet (72), and two ends of the internal pipeline (70) are respectively connected to the water inlet (71) and the hot water outlet (72); The water heater circulation pipeline is composed of an external hot water pipe (81), a return pipe (82) and an external cold water pipe (83); one end of the external hot water pipe (81) is connected to the hot water outlet (72), and the other end is connected to the external cold water pipe (83) through the return pipe (82); one end of the external cold water pipe (83) away from the return pipe (82) is connected to the water inlet (71); The first detection device (1) is installed on the external hot water pipe (81), the second detection device (1) is installed on the return water pipe (82), the third detection device (1) is installed on the external cold water pipe (83), and the fourth detection device (1) is installed on the external cold water pipe (83) and close to the water inlet (71).

7. The control method of a water heater zero cold water performance detection system according to claim 1, characterized in that: The step of obtaining the water temperature fluctuation value △T1 of the first test point specifically includes: S41: After the water flow switch unit (12) is turned on for a period of time, the water temperature value is collected once at a preset time interval, and the collection is performed N times to obtain a temperature data group; S42: extracting the maximum value and the minimum value from the temperature data group; S43: Calculate the water temperature fluctuation value △T1 of the first test point according to the maximum value and the minimum value.

8. The control method of a water heater zero cold water performance detection system according to claim 1, characterized in that: While obtaining the water temperature fluctuation value ΔT1 of the first test point, the water flow data set of the test point is first obtained through the water flow detection unit (13), and then the average water flow value Q1 is calculated based on the obtained water flow data set.

9. A control method for a water heater zero cold water performance detection system according to any one of claims 1 to 4 or any one of claims 7 to 8, characterized in that: The control method further comprises the following steps: S6: Repeat steps S1 to S3; S7: when the instant heating of the water heater is completed, the water flow switch unit (12) of the second test point is turned on, the water temperature stabilization time t2 of the second test point is recorded, and the water temperature fluctuation value △T2 of the second test point is obtained; S8: Determine the zero cold water performance of the water heater based on the water temperature stabilization time t2 and the water temperature fluctuation value △T2 of the second test point.

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