Gas water heater and control method and device thereof

Abstract

The invention discloses a control method of a gas water heater, a control device of the gas water heater and the gas water heater, and relates to the technical field of gas water heaters. The method comprises the steps that when the gas water heater receives a heating instruction, the current water inlet flow of the gas water heater is obtained; and when the current water inlet flow is larger than the preset starting water flow, the water inlet flow of the gas water heater is adjusted to the preset starting water flow, and the inlet water is heated. According to the technical scheme, when the current water inlet flow is larger than the preset starting water flow, the water inlet flow of the gas water heater is adjusted to the preset starting water flow, so that the gas water heater is started at a relatively small water flow, the water outlet temperature of the gas water heater can rapidly reach the target water temperature of a user, the minimum gas consumption can be used, and the energy consumption is reduced. And the water outlet temperature of the gas water heater rapidly reaches the target water temperature of a user through minimum heat loss, so that the heat loss of the gas water heater in the starting stage is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of gas water heaters, and in particular to a gas water heater and a control method and a control device thereof. Background Art

[0002] During the startup process of the gas water heater, the control device calculates the required heat load and gas flow rate based on the detected water flow rate and water inlet temperature, as well as the target temperature set by the user, and controls the opening of the gas proportional valve according to the gas flow rate. However, it usually takes 30-60 seconds from the time the user issues the startup command to the time the water temperature is heated to the user's target hot water temperature. During this process, in order to heat the water temperature to the user's target hot water temperature as quickly as possible, a larger gas flow rate is usually used, which requires more gas to be consumed during the startup phase of the gas water heater, resulting in higher heat loss during the startup phase of the gas water heater. Summary of the invention

[0003] The main purpose of the present invention is to provide a control method for a gas water heater, aiming to reduce the heat loss during the startup phase of the gas water heater.

[0004] To achieve the above object, the present invention provides a control method for a gas water heater, the control method comprising the following steps:

[0005] When the gas water heater receives a heating instruction, the current water inlet flow of the gas water heater is obtained;

[0006] When the current water inlet flow rate is greater than the preset starting water flow rate, the water inlet flow rate of the gas water heater is adjusted to the preset starting water flow rate, and the inlet water is heated.

[0007] In one embodiment, before the step of adjusting the inlet water flow of the gas water heater to the preset starting water flow when the current inlet water flow is greater than the preset starting water flow and heating the inlet water, the control method further includes:

[0008] The water flow interval in which the current water inlet flow is located is determined according to the current water inlet flow, and the minimum water flow in the water flow interval is used as the preset starting water flow.

[0009] In one embodiment, the water flow interval includes a first sub-water flow interval and a second sub-water flow interval, the water flow in the first sub-water flow interval is greater than the water flow in the second sub-water flow interval; the minimum flow in the first sub-water flow interval is greater than or equal to the minimum starting water flow of the gas water heater.

[0010] In one embodiment, after the step of adjusting the inlet water flow of the gas water heater to the preset starting water flow when the current inlet water flow is greater than the preset starting water flow and heating the inlet water, the control method further comprises:

[0011] When the outlet water temperature of the gas water heater reaches a first preset temperature, the water inlet flow rate is adjusted to a first preset water flow rate, and the first preset water flow rate is greater than the preset starting water flow rate.

[0012] In one embodiment, during the process of adjusting the water inlet flow rate to a first preset water flow rate, the water outlet temperature is controlled to be within a first preset temperature range.

[0013] In one embodiment, the first preset temperature is greater than the target temperature.

[0014] In one embodiment, heating the incoming water comprises:

[0015] Get the water inlet temperature and target temperature of the gas water heater;

[0016] Determining a target temperature rise according to the water inlet temperature and the target temperature;

[0017] Determining a target heat output according to the target temperature rise and the preset starting water flow rate;

[0018] The opening of the gas proportional valve is adjusted according to the target heat output.

[0019] In one embodiment, before heating the incoming water, the fan is started to complete the pre-cleaning of the combustion chamber.

[0020] To achieve the above object, the present invention provides a control device for a gas water heater, the control device for the gas water heater comprising:

[0021] Memory;

[0022] Processor; and

[0023] A control program of the gas water heater is stored in the memory and executed by the processor. When the control program of the gas water heater is executed by the processor, the control method of the gas water heater described in any of the above embodiments is implemented.

[0024] To achieve the above object, the present invention further proposes a gas water heater, characterized in that the gas water heater uses the control method of the gas water heater described in any of the above embodiments; or has the control device of the gas water heater described in any of the above embodiments.

[0025] The present invention provides a gas water heater and a control method and a control device thereof. When the gas water heater receives a heating instruction, the current water inlet flow of the gas water heater is obtained; and when the current water inlet flow is greater than the preset starting water flow, the water inlet flow of the gas water heater is adjusted to the preset starting water flow, and the inlet water is heated. The technical solution of the present invention adjusts the water inlet flow of the gas water heater to the preset starting water flow when the current water inlet flow is greater than the preset starting water flow, so as to start with a relatively small water flow, so that the outlet water temperature of the gas water heater can quickly reach the user's target water temperature. The water flow smaller than the actual water inlet flow is used as the starting flow, and the gas consumed is relatively small. In this way, the outlet water temperature of the gas water heater can quickly reach the user's target water temperature with minimum gas consumption and minimum heat loss, thereby reducing the heat loss in the startup stage of the gas water heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0027] Figure 1 It is a structural schematic diagram of an embodiment of a gas water heater of the present invention;

[0028] Figure 2 It is a structural schematic diagram of an embodiment of a control system of a gas water heater of the present invention;

[0029] Figure 3 It is a structural schematic diagram of an embodiment of a control device for a gas water heater of the present invention;

[0030] Figure 4 It is a structural schematic diagram of an embodiment of a control method for a gas water heater of the present invention.

[0031] Description of Figure Numbers:

[0032] Label name Label name 100 case 10 Gas water heater 200 Fan 20 Control System 300 Heat Exchanger 21 System control unit 400 Gas valve 22 Gas control unit 500 Burner 23 Fan control unit 700 Water inlet valve 24 Pressure detection unit 600 Controls 25 Water flow detection unit 610 Memory 620 processor

[0033] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1 , Figure 1 The schematic diagram of the structure of an embodiment of a gas water heater 10 involved in the embodiment of the present invention. The gas water heater 10 includes a housing 100, and a fan 200, a heat exchanger 300, a gas valve 400, a control device 600, a burner 500, a combustion chamber, an air inlet pipe and a smoke exhaust pipe arranged in the housing 100. The burner 500 is arranged between the fan 200 and the smoke exhaust pipe, the heat exchanger 300 is arranged between the burner 500 and the smoke exhaust pipe, and the combustion chamber is arranged between the burner 500 and the smoke exhaust pipe. The gas pipeline is used to transport gas to the burner 500, and the fan 200 is used to transport air to the burner 500. The gas valve 400 is arranged on the gas pipeline and is used to cut off, connect and adjust the gas in the gas pipeline. The burner 500 is provided with a plurality of injection ports, through which the fan 200 and the gas pipeline deliver air and gas to the burner 500, and then the burner 500 injects the gas mixed with the air and gas into the combustion chamber for combustion, and finally exchanges heat with the combustion chamber through the heat exchanger 300 to heat the water in the water pipe. The smoke exhaust pipe is used to exhaust the smoke exhausted from the combustion in the combustion chamber to the outside.

[0036] Reference Figure 2 , Figure 2 FIG. 2 is a structural block diagram of an embodiment of a control system 20 of a gas water heater 10 of the present invention. Figure 2As shown, the control system 20 of the gas water heater 10 may include a system control unit 21, a gas control unit 22, a fan 200 control unit, a pressure detection unit 24 and a water flow detection unit 25. Among them, the system control unit 21 is a core control unit, which is mainly used to analyze the operating state of the gas water heater 10 and control the operation of each component in the gas water heater 10. The gas control unit 22 is mainly used to control the supply of gas. For example, the gas control unit 22 can be connected to the gas valve 400, and the gas control unit 22 can receive the set output value sent by the system control unit 21, and then control the gas valve 400 to open to the corresponding opening according to the set output value, and adjust the amount of gas delivered to the burner 500. The fan 200 control unit is mainly used to control the opening and speed of the fan 200. The fan 200 control unit can receive the set output value sent by the system control unit 21, and then control the fan 200 to run at the corresponding speed according to the set output value. The pressure detection unit 24 is mainly used to detect the pressure state in the gas water heater 10, which can be composed of a pressure sensor. The water flow detection unit 25 is mainly used to detect the water inlet and outlet of the gas water heater 10, and can be composed of a flow sensor. The system control unit 21 receives the detection signals fed back by the pressure detection unit 24 and the water flow detection unit 25, analyzes the operating state of the gas water heater 10 according to the detection signals, and executes the corresponding control process.

[0037] Those skilled in the art will understand that Figure 1 and Figure 2 The structure shown in the figure does not constitute a limitation on the control device of the gas water heater 10, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently. The system control unit 21 may include a processor 620 and a memory 610, and the memory 610 may include an operating system, a network communication module, a user interface module, and a control program of the gas water heater 10. The system control unit 21 may call the control program of the gas water heater 10 stored in the memory 610 through the processor 620, and execute the control method of the gas water heater 10 provided in the embodiment of the present invention.

[0038] Based on the above hardware structure, an embodiment of the control method of the gas water heater 10 of the present invention is proposed. Figure 4 , Figure 4 1 is a flow chart of a first embodiment of a control method for a gas water heater 10 of the present invention, and provides a first embodiment of a control method for a gas water heater 10 of the present invention.

[0039] In this embodiment, the structure of the gas water heater 10 can refer to the above, and the control method of the gas water heater 10 includes the following steps:

[0040] Step S10: when the gas water heater 10 receives the heating instruction, the current water inlet flow of the gas water heater 10 is obtained;

[0041] It should be understood that the execution subject of this embodiment can be the system control unit 21 in the control system 20 of the gas water heater 10, which has functions such as data processing, data communication and program running. Of course, it can also be other devices with similar functions, and this embodiment does not limit this. The process of starting the heating of the gas water heater 10 usually starts the fan 200 first, then starts the gas valve 400 to deliver gas to the combustion chamber of the burner 500, and then ignites for heating. This implementation mainly involves the control of various components in the gas water heater 10 before starting ignition and heating. The gas water heater 10 is usually an instant-on water heater.

[0042] The water flow detection unit 25 can be arranged on the water outlet pipe, or on a water pipe connected to the water outlet pipe. The system control unit 21 receives the detection signal fed back by the water flow detection unit 25, so as to obtain the water flow of the water system of the gas water heater 10.

[0043] In this embodiment, the user turns on the water inlet switch of the gas water heater 10, and water can flow into the gas water heater 10. At this time, water flows through the water system of the gas water heater 10, and the water flow detection unit 25 can detect the water inlet flow of the water system of the gas water heater 10, and convert the detected water inlet flow into a detection signal and transmit it to the system control unit 21. The system control unit 21 also usually uses this as a heating instruction. When a valid heating instruction is obtained, the gas water heater 10 will start the fan 200, open the gas valve 400, and start the ignition device, thereby heating the incoming water.

[0044] Step S20: When the current water inlet flow rate is greater than the preset starting water flow rate, the water inlet flow rate of the gas water heater 10 is adjusted to the preset starting water flow rate, and the inlet water is heated.

[0045] In this embodiment, the preset starting water flow rate may be greater than or equal to the minimum starting water flow rate of the gas water heater 10, wherein the minimum starting water flow rate of the gas water heater 10 refers to that the water inlet flow rate of the gas water heater 10 must be greater than the minimum starting water flow rate, that is, when the system control unit 21 obtains a valid heating instruction, the gas water heater 10 will start the fan 200, open the gas valve 400, and start the ignition device, thereby heating the incoming water. In this embodiment, the preset starting water flow rate may be the minimum starting water flow rate of the gas water heater 10, or may be other set values, which are not specifically limited here.

[0046] It should be noted that the minimum starting water flow is not the minimum working flow at which the gas water heater 10 can operate. After the gas water heater 10 operates normally, the water inlet flow can be reduced. As long as the water inlet flow is higher than the shut-off water flow of the gas water heater 10, the gas water heater 10 can operate normally.

[0047] Among them, the heating of the incoming water includes obtaining the inlet water temperature and the target temperature of the gas water heater 10; determining the target temperature rise according to the inlet water temperature and the target temperature; determining the target heat output according to the target temperature rise and the preset starting water flow; and adjusting the opening of the gas proportional valve according to the target heat output.

[0048] According to the technical solution of the present invention, during the startup phase of the gas water heater 10, when the current water inlet flow rate is greater than the preset startup water flow rate, the water inlet flow rate of the gas water heater 10 is adjusted to the preset startup water flow rate, thereby starting with a relatively small water flow rate. This allows the outlet water temperature of the gas water heater 10 to quickly reach the user's target water temperature. A water flow rate that is smaller than the actual water inlet flow rate is used as the startup flow rate, and the gas consumed is also relatively small. In this way, the outlet water temperature of the gas water heater 10 can quickly reach the user's target water temperature with minimal gas consumption and minimal heat loss, thereby reducing the heat loss during the startup phase of the gas water heater 10.

[0049] Furthermore, after the step of adjusting the inlet water flow of the gas water heater 10 to the preset starting water flow when the current inlet water flow is greater than the preset starting water flow and heating the inlet water, the control method further includes:

[0050] Step S30: When the outlet water temperature of the gas water heater 10 reaches a first preset temperature, the water inlet flow rate is adjusted to a first preset water flow rate, and the first preset water flow rate is greater than the preset start-up water flow rate.

[0051] The first preset water flow rate may be the current water inlet flow rate obtained when the gas water heater 10 receives the heating instruction, or may be other values ​​that are higher than the preset start-up water flow rate and lower than the current water inlet flow rate obtained when the gas water heater 10 receives the heating instruction. Usually, in order to ensure the user experience, the first preset water flow rate is the current water inlet flow rate obtained when the gas water heater 10 receives the heating instruction.

[0052] In one embodiment, in order to ensure the user experience, in the process of adjusting the water inlet flow rate to the first preset water flow rate, the water outlet temperature is controlled to be in a first preset temperature range, wherein the temperature value corresponding to the first preset temperature range is within the range before and after the target temperature. For example, assuming that the target temperature is 40°, the first preset temperature range is generally 39.5° to 40.5°.

[0053] Preferably, the first preset temperature is greater than the target temperature, that is, when the water outlet temperature is slightly higher than the target temperature, the water flow rate is increased, so that in the process of increasing the water flow rate, the temperature change will not drop too much compared to the target temperature, thereby improving the user experience.

[0054] In one embodiment, when the current inlet water flow rate is greater than the preset starting water flow rate, before the step of adjusting the inlet water flow rate of the gas water heater 10 to the preset starting water flow rate and heating the inlet water, the control method further includes:

[0055] The water flow interval in which the current water inlet flow is located is determined according to the current water inlet flow, and the minimum water flow in the water flow interval is used as the preset starting water flow.

[0056] In this embodiment, in order to shorten the time for the gas water heater 10 to reach the target water flow and target temperature, the present invention divides the preset starting water flow into zones. In this way, the adjustment time of the water proportional valve can be reduced, so that the adjustment can be completed as much as possible before ignition and combustion; in addition, the time for the water flow to increase from the preset starting water flow to the first preset temperature after the temperature rise reaches the preset temperature rise can be reduced, so that the user can obtain the required amount of hot water as soon as possible.

[0057] Furthermore, the water flow interval includes a first sub-water flow interval and a second sub-water flow interval, the water flow in the first sub-water flow interval is greater than the water flow in the second sub-water flow interval; the minimum flow in the first sub-water flow interval is greater than or equal to the minimum start-up water flow of the gas water heater 10. Of course, depending on the specifications of the gas water heater 10, the water flow interval may also include a third sub-water flow interval, a fourth sub-water flow interval, or a fifth sub-water flow interval, or the first sub-water flow interval and the second sub-water flow interval may be divided into a lower level of water flow intervals.

[0058] In one embodiment, in order to avoid ignition explosion and flue blockage failure of the gas water heater 10 and reduce the waiting time of the user, thereby saving water resources, the control method further includes:

[0059] Before heating the incoming water, the fan 200 is started to complete the pre-cleaning of the combustion chamber.

[0060] In the above steps, the main purpose of the pre-cleaning is to remove the residual combustible gas inside the water heater due to the long-term accumulation of fine leaks, so as to ensure the normal ignition of the water heater and avoid deflagration. As long as the time interval between the pre-cleaning time and the ignition of the water heater is not long, and the amount of gas accumulated in the water heater is small, there will be no deflagration when ignited. Of course, for a deflagration to occur in the gas water heater 10, the gas in the combustion chamber needs to reach a certain concentration. Before this concentration lower limit is reached, even if an open flame is ignited, it will not cause a gas deflagration. This is for the safety of the gas water heater 10.

[0061] In an exemplary embodiment, the water outlet temperature is set to T1, the water inlet temperature is T0, and the start-up water flow rate is preset to Q1. When the user turns on the faucet or shower, the external water source enters from the water inlet of the gas water heater 10. The temperature sensor on the water proportional valve of the gas water heater 10 detects the water inlet temperature T1, and the water flow detection unit 25 on the water proportional valve detects the water flow rate Q. Assuming Q>Q1, the water flow detection unit 25 transmits a signal to the system control unit 21, and the system control unit 21 starts the fan 200 for pre-sweeping, and at the same time, the water flow rate is reduced from Q to Q1 through the water proportional valve. After the pre-sweeping is turned on, and according to the gas volume corresponding to the preset start-up water flow rate Q1, the opening of the gas valve 400 is adjusted to make the water flow rate and the gas consumption most suitable. When the water outlet temperature reaches T1±t, it can be considered that the set temperature T1 has been reached, and then the water flow rate is increased, and the water outlet temperature fluctuation is kept within T1±t during the process of increasing the water inlet flow rate. Among them, the value of t is usually about 2% of T1. In this way, the technical solution of this embodiment can quickly heat the water temperature from T0 to T1 to obtain the target temperature rise. In this way, the target temperature rise can be obtained with minimum gas consumption and minimum heat loss. After obtaining the target temperature, the water flow is gradually increased to the water inlet flow when the user turns on the machine, which can ensure the user's water demand.

[0062] In another exemplary embodiment, the water outlet temperature is set to T1, the water inlet temperature is T0, the first preset start-up water flow rate is Q1, and the second preset start-up water flow rate is Q2, wherein Q2>Q1. When the faucet or shower is turned on, the external water source enters from the water inlet of the gas water heater 10, the temperature sensor on the water proportional valve of the gas water heater 10 detects the water inlet temperature T1, and the water flow detection unit 25 on the water proportional valve detects the water flow rate Q. Assuming that Q>Q2, the water flow detection unit 25 transmits a signal to the system control unit 21, and the system control unit 21 starts the fan 200 for pre-sweeping, and at the same time, the water flow rate is reduced from Q to Q2 through the water proportional valve. After the pre-sweeping is turned on, and according to the gas volume corresponding to the preset start-up water flow rate Q2, the opening of the gas valve 400 is adjusted to make the water flow rate and the gas consumption most suitable. After the pre-sweeping is finished and turned on, and according to the gas volume corresponding to the preset start-up water flow rate Q2, the opening of the gas valve 400 is adjusted to make the water flow rate and the gas consumption most suitable. When the outlet water temperature reaches T1±t, it can be considered that the set temperature T1 has been reached, and then the water flow rate is increased. In the process of increasing the inlet water flow rate, the outlet water temperature fluctuation is kept within T1±t. Among them, the value of t is usually about 2% of T1. In this way, the technical solution of this embodiment can quickly heat the water temperature from T0 to T1 to obtain the target temperature rise. In this way, the target temperature rise can be obtained with minimal gas consumption and minimal heat loss. After obtaining the target temperature, the water flow is gradually increased to the inlet water flow rate when the user turns on the machine, which can ensure the user's water demand. In addition, the time for the water flow rate to increase from Q2 to Q after the temperature rise reaches the preset temperature rise can also be reduced, so that the user can obtain the required amount of hot water as soon as possible, thereby improving the user's experience.

[0063] In addition, refer to Figure 3 The present invention further provides a control device 600 for a gas water heater 10, wherein the control device 600 for the gas water heater 10 comprises:

[0064] Memory 610;

[0065] Processor 620; and

[0066] The control program of the gas water heater 10 is stored in the memory 610 and executed by the processor 620. When the control program of the gas water heater 10 is executed by the processor 620, it at least implements the control method of the gas water heater 10 described in any of the above-mentioned embodiments. It can be understood that since the control device 600 of the gas water heater 10 of the present invention implements the control method of the gas water heater 10 of any of the above-mentioned embodiments, the embodiment of the control device 600 of the gas water heater 10 of the present invention includes all technical solutions of all embodiments of the control method of the gas water heater 10 mentioned above, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0067] In addition, the present invention further proposes a gas water heater 10, which uses the control method of the gas water heater 10 described in any of the above embodiments or includes the control device 600 of the gas water heater 10 described in any of the above embodiments. It can be understood that since the present invention uses the control method or control device 600 of the gas water heater 10 of any of the above embodiments on the gas water heater 10, the embodiment of the gas water heater 10 of the present invention includes all technical solutions of all embodiments of the control method or control device 600 of the gas water heater 10, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0068] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0069] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words may be interpreted as names.

[0070] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product is stored in a storage medium (such as a read-only memory image (ROM) / random access memory (RAM), a disk, or an optical disk), including a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0071] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A control method for a gas water heater, characterized in that: The control method comprises the following steps: When the gas water heater receives a heating instruction, the current water inlet flow of the gas water heater is obtained; When the current water inlet flow rate is greater than the preset starting water flow rate, the water inlet flow rate of the gas water heater is adjusted to the preset starting water flow rate, and the inlet water is heated.

2. The control method of the gas water heater according to claim 1, characterized in that: Before the step of adjusting the inlet water flow of the gas water heater to the preset starting water flow when the current inlet water flow is greater than the preset starting water flow and heating the inlet water, the control method further includes: The water flow interval in which the current water inlet flow is located is determined according to the current water inlet flow, and the minimum water flow in the water flow interval is used as the preset starting water flow.

3. The control method of the gas water heater according to claim 2, characterized in that: The water flow interval includes a first sub-water flow interval and a second sub-water flow interval, the water flow in the first sub-water flow interval is greater than the water flow in the second sub-water flow interval; the minimum flow in the first sub-water flow interval is greater than or equal to the minimum starting water flow of the gas water heater.

4. The control method of the gas water heater according to claim 1, characterized in that: After the step of adjusting the inlet water flow of the gas water heater to the preset starting water flow when the current inlet water flow is greater than the preset starting water flow, and heating the inlet water, the control method further comprises: When the outlet water temperature of the gas water heater reaches a first preset temperature, the water inlet flow rate is adjusted to a first preset water flow rate, and the first preset water flow rate is greater than the preset starting water flow rate.

5. The control method of the gas water heater according to claim 4, characterized in that: In the process of adjusting the water inlet flow rate to the first preset water flow rate, the water outlet temperature is controlled to be within the first preset temperature range.

6. The control method of the gas water heater according to claim 4, characterized in that: The first preset temperature is greater than the target temperature.

7. The control method of the gas water heater according to claim 1, characterized in that: The heating of the incoming water comprises: Get the water inlet temperature and target temperature of the gas water heater; Determining a target temperature rise according to the water inlet temperature and the target temperature; Determining a target heat output according to the target temperature rise and the preset starting water flow rate; The opening of the gas proportional valve is adjusted according to the target heat output.

8. The control method of the gas water heater according to claim 1, characterized in that: Before heating the incoming water, start the fan to complete the pre-cleaning of the combustion chamber.

9. A control device for a gas water heater, characterized in that: The control device of the gas water heater comprises: Memory; Processor; and A control program of the gas water heater is stored in the memory and executed by the processor. When the control program of the gas water heater is executed by the processor, the control method of the gas water heater according to any one of claims 1 to 8 is implemented.

10. A gas water heater, characterized in that: The gas water heater uses the control method of the gas water heater according to any one of claims 1 to 8; Or it includes the control device of the gas water heater as claimed in claim 9.

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