A method for controlling a water pump of a gas water heater

Abstract

The present invention relates to the technical field of intelligent household appliances, and specifically relates to a control method for a water pump of a gas water heater, comprising the following steps: The controller periodically detects whether the boost button is pressed. If it is pressed, the next step is entered; otherwise, this step is repeated. The controller reads the inlet water flow sensor and the outlet water temperature sensor. If the inlet water flow is within the preset flow range and the outlet water temperature is lower than the preset first threshold, the controller starts the water pump to boost the pressure and enters the next step; otherwise, no operation is performed. After starting the water pump to boost the pressure, the controller periodically detects the outlet water temperature and the inlet water flow. If the outlet water temperature exceeds the preset second threshold or the inlet water flow is less than the preset flow threshold, the controller controls the water pump to stop boosting the pressure and returns to the first step. The beneficial technical effects of the present invention include: By checking the inlet water flow and the outlet water temperature, it is possible to avoid the water pump from idling when the inlet water flow is low, and at the same time avoid a large amount of air in the inlet water, resulting in too high a water temperature rise.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent household appliances, and particularly relates to a control method for a water pump of a gas water heater. Background Art

[0002] Currently, for household zero - cold - water gas water heaters, a water pump is usually configured, and a pressurization mode is usually set on the operation interface. When the user is using the water heater and the water volume is too small, the user can start the pressurization function of the water pump to increase the water volume and improve comfort. In the traditional pressurization process, the main controller sends a signal to the water pump to trigger the water pump to start pressurizing. Due to the differences in the user's water pipeline environment or peak water - using periods, the water volume is too low, there is air in the pipeline, and air accumulates in the water pump, resulting in an air - suction phenomenon. In this state, the main controller detects the water volume inaccurately, and the water temperature fluctuates greatly. The conventional method for controlling pressurization is that after the main controller receives the user's pressurization instruction, the main controller sends an action signal to the water pump. If the water pressure in the pipeline is low and there is air in the pipeline, at this time the water pump idles, and there is air in the actual water pipeline supplied to the machine. The water volume detected by the main controller fluctuates repeatedly, resulting in repeated adjustment of the opening of the gas proportional valve, the rotation speed of the blower, and the state of the burner, and the water temperature fluctuates greatly. Therefore, it is necessary to study the technology for stabilizing the water temperature of gas water heaters.

[0003] For example, Chinese Patent CN111854175A, with a publication date of October 30, 2020, discloses a control method for a gas water heater and its circulating water pump. Among them, the control method includes: calculating the head required by the circulating water pump according to the obtained length of the circulating pipeline; obtaining the maximum water pump flow rate of the circulating water pump at this head according to the preset relationship between the head of the circulating water pump and the maximum water pump flow rate of the circulating water pump; calculating the longest time for circulating heating of the circulating pipeline according to the water volume in the obtained circulating pipeline and the minimum start - up flow rate of the gas water heater; judging whether the longest time is less than the shortest time preset for the circulating heating of the circulating pipeline; if the longest time is less than the shortest time, setting the working flow rate of the circulating water pump to be less than the maximum water pump flow rate; when the gas water heater is performing pre - heating work, controlling the circulating water pump to work according to the determined working flow rate. Although its technical solution can effectively solve the problem that the existing water pump speed - regulation method of water heaters affects the normal pre - heating of water heaters, its technical solution cannot solve the problem of water temperature fluctuation caused by the fluctuation of the water inlet volume of gas water heaters. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: the current lack of a control scheme for the pressurization water pump of a gas water heater that can suppress water temperature fluctuations. A control method for a gas water heater water pump is proposed, which can achieve the effect of suppressing water temperature fluctuations.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: A method for controlling a water pump of a gas water heater, the gas water heater includes a boost button, a controller, a blower, a gas proportional valve, an inlet water flow sensor, an outlet water flow sensor, an inlet water temperature sensor, and an outlet water temperature sensor. The inlet water flow sensor detects the inlet water flow at the water inlet, the outlet water flow sensor detects the outlet water flow at the water outlet, and the inlet water temperature sensor and the outlet water temperature sensor respectively detect the inlet water temperature at the water inlet and the outlet water temperature at the water outlet, including the following steps:

[0006] The controller periodically detects whether the boost button is pressed. If it is pressed, it proceeds to the next step; otherwise, this step is repeated.

[0007] The controller reads the inlet water flow sensor and the outlet water temperature sensor. If the inlet water flow is within a preset flow range and the outlet water temperature is lower than a preset first threshold, the controller starts the water pump for boosting and proceeds to the next step; otherwise, no operation is performed.

[0008] After starting the water pump for boosting, the controller periodically detects the outlet water temperature and the inlet water flow. If the outlet water temperature exceeds a preset second threshold or the inlet water flow is less than a preset flow threshold, the controller controls the water pump to stop boosting and returns to the first step; otherwise, after waiting for a preset duration, this step is executed again.

[0009] Preferably, after starting the water pump for boosting, the controller periodically detects the inlet water flow and adjusts the water pump speed gear according to the inlet water flow, specifically including the following steps:

[0010] The controller stores a plurality of preset water flow ranges, and each water flow range corresponds to a water pump gear.

[0011] The controller determines the water flow range into which the inlet water flow falls at a period T1 to obtain the water pump gear corresponding to the inlet water flow.

[0012] If the current water pump gear is different from the water pump gear corresponding to the current inlet water flow, the water pump gear is adjusted to the water pump gear corresponding to the current inlet water flow; otherwise, when waiting for the next period, the previous step is returned to for execution.

[0013] Preferably, there is an overlap area between the plurality of water flow ranges stored in the controller. If the current inlet water flow is within the overlap area, the water pump gear is locked.

[0014] Preferably, the controller calculates the change rate of the inlet water flow within a preset duration. If the change rate of the inlet water flow exceeds a preset threshold, the water pump gear is changed when the inlet water flow is within the overlap area; otherwise, if the change rate of the inlet water flow does not exceed the preset threshold, the water pump gear is locked when the inlet water flow is within the overlap area.

[0015] Preferably, the water flow rate range is the interval [3, 4], the interval (4, 5], and the interval (5, 6], the unit of the water flow rate range is L / min, and the corresponding water pump gears are gears 1 to 3.

[0016] Preferably, the period T1 is 10 seconds.

[0017] Preferably, after the water pump is pressurized, the controller periodically detects the outlet water temperature and fine-tunes the water pump speed according to the outlet water temperature, which specifically includes the following steps:

[0018] The controller reads the outlet water temperature at a period T2;

[0019] If the temperature rises beyond a preset first amplitude threshold, the water pump speed is increased by a preset step;

[0020] If the temperature drops beyond a preset second amplitude threshold, the water pump speed is decreased by a preset step.

[0021] Preferably, the gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, the outlet water temperature, the inlet water flow rate, the proportional valve opening, and the inlet gas flow rate, and fine-tunes the water pump speed according to the inlet water temperature, the outlet water temperature, the inlet water flow rate, the proportional valve opening, and the inlet gas flow rate, which specifically includes the following steps:

[0022] The controller reads the inlet water temperature, the outlet water temperature, the inlet water flow rate, the proportional valve opening, and the inlet gas flow rate at a period T2;

[0023] According to the outlet water temperature and the inlet water temperature set by the user, calculate the heat required for water heating, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the outlet water temperature set by the user, and T_in is the inlet water temperature;

[0024] Calculate the heat Q_gas required to be provided by gas according to Q_water, Q_gas = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_gas;

[0025] When the outlet water temperature exceeds the outlet water temperature set by the user, the water pump speed is increased by a preset step, and when the outlet water temperature is lower than the outlet water temperature set by the user, the water pump speed is decreased by a preset step.

[0026] Preferably, after the water pump is pressurized, the controller periodically detects the outlet water temperature and adjusts the fan speed according to the outlet water temperature, which specifically includes the following steps:

[0027] The controller reads the outlet water temperature at a period T2;

[0028] If the temperature rises beyond a preset first amplitude threshold, the fan speed is decreased by a preset step;

[0029] If the temperature drops by more than a preset second amplitude threshold, the fan speed is increased by a preset step size.

[0030] Preferably, the gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and inlet gas flow rate, and adjusts the fan speed according to the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and inlet gas flow rate. The specific steps are as follows:

[0031] The controller reads the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and inlet gas flow rate at a period T2.

[0032] According to the outlet water temperature and inlet water temperature set by the user, calculate the heat required for water heating, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the outlet water temperature set by the user, and T_in is the inlet water temperature.

[0033] Calculate the heat Q_gas required to be provided by the gas according to Q_water, Q_gas = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_gas.

[0034] When the outlet water temperature exceeds the outlet water temperature set by the user, the fan speed is decreased by a preset step size. When the outlet water temperature is lower than the outlet water temperature set by the user, the fan speed is increased by a preset step size.

[0035] The beneficial technical effects of the present invention include: By checking the inlet water flow rate and outlet water temperature before turning on the booster pump, it is avoided that when the inlet water flow rate is low, the pump runs idly, affecting the pump life, and at the same time, it is avoided that a large amount of air is contained in the inlet water, resulting in too high a water temperature under the same gas heating, which deteriorates the user experience; By dynamically adjusting the gear of the pump after boosting by the pump, the supply of hot water is adapted to the inlet water flow rate; By fine-tuning the pump speed and fan speed, the water temperature is made more stable.

[0036] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The following further describes the present invention with reference to the drawings:

[0038] Figure 1 It is a schematic flow chart of the water pump control method of the gas water heater according to the embodiment of the present invention.

[0039] Figure 2 It is a schematic flow chart of the method for adjusting the water pump speed gear according to the inlet water flow rate according to the embodiment of the present invention.

[0040] Figure 3 Schematic flow diagram of the method for fine-tuning the water pump speed according to the outlet water temperature in an embodiment of the present invention.

[0041] Figure 4 Schematic flow diagram of the method for fine-tuning the water pump speed in an embodiment of the present invention.

[0042] Figure 5 Schematic flow diagram of the method for adjusting the fan speed in an embodiment of the present invention. Detailed implementation manners

[0043] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0044] In the following description, terms such as "inner", "outer", "upper", "lower", "left", "right", etc. indicating orientations or positional relationships are only for convenience of describing the embodiments and simplifying the description, rather than indicating or implying that the devices or elements referred to must have specific orientations, be constructed and operated in specific orientations, and therefore should not be construed as limitations of the present invention.

[0045] Before introducing the technical solutions of this embodiment, the background situation of this embodiment will be introduced. The zero-cold-water gas water heater is currently the most popular gas water heater product. A zero-cold-water gas water heater means that the gas water heater can draw back the cold water in the hot water pipe for heating. At this time, when the water heater faucet or shower head is opened, hot water will appear, solving the problem of discharging a section of cold water before hot water appears when the hot water switch is opened. Usually, the return water pipe is used to realize the back-drawing of cold water. The zero-cold-water gas water heater has the advantage of a wide range of applications and can be installed and used in both new and old residential buildings. The disadvantage of the zero-cold-water gas water heater is that the water in both the cold water return pipe and the water inlet pipe needs to enter the heat exchanger through a water pump, which increases the resistance of the water entering the heat exchanger and also increases the power consumption to a certain extent. At the same time, the amount of water entering the heat exchanger is determined by the speed of the water pump and the air content in the water inlet pipe. In some residential communities, due to the unstable water pressure or the presence of air in the water supply pipe, the actual water supply of the water pump is lower than the theoretical water supply at the corresponding speed. The detection of the water inflow is based on the water pump speed, which cannot prevent the water temperature from rising beyond expectations under the same gas combustion condition, resulting in a final increase in the water temperature, affecting the user experience and leading to user complaints about the product. At the same time, the idling of the water pump will also affect the life of the water pump. Therefore, it is necessary to study and improve the control method of the water pump speed to solve the problem of current fluctuating water supply temperature.

[0046] This embodiment describes a method for controlling a water pump of a gas water heater. The gas water heater includes a boost button, a controller, a blower, a gas proportional valve, an inlet water flow sensor, an outlet water flow sensor, an inlet water temperature sensor, and an outlet water temperature sensor. The inlet water flow sensor detects the inlet water flow at the water inlet, the outlet water flow sensor detects the outlet water flow at the water outlet, and the inlet water temperature sensor and the outlet water temperature sensor respectively detect the inlet water temperature at the water inlet and the outlet water temperature at the water outlet. Please refer to the appendix Figure 1 , and the water pump control method includes the following steps:

[0047] Step A01) The controller periodically detects whether the boost button is pressed. If it is pressed, proceed to the next step; otherwise, repeat this step.

[0048] Step A02) The controller reads the inlet water flow sensor and the outlet water temperature sensor. If the inlet water flow is within the preset flow range and the outlet water temperature is lower than the preset first threshold, the controller starts the water pump for boosting and proceeds to the next step; otherwise, no operation is performed.

[0049] Step A03) After starting the water pump for boosting, the controller periodically detects the outlet water temperature and the inlet water flow. If the outlet water temperature exceeds the preset second threshold or the inlet water flow is less than the preset flow threshold, control the water pump to stop boosting and return to the first step; otherwise, wait for the preset duration and then re - execute this step.

[0050] Before starting the water pump for boosting, check the inlet water flow and the outlet water temperature. If the inlet water flow is too low or too high, do not start boosting. If the outlet water temperature is higher than the threshold, do not start boosting to prevent the water pump from idling or causing the water temperature to rise too high.

[0051] This embodiment not only checks before starting the water pump for boosting, but also checks some parameters after starting the water pump for boosting to determine whether to close the boost. After starting the water pump for boosting, the controller periodically detects the inlet water flow and adjusts the water pump speed gear according to the inlet water flow. Please refer to the appendix Figure 2 , and specifically includes the following steps:

[0052] Step B01) The controller stores several preset water flow ranges, and each water flow range corresponds to a water pump gear.

[0053] Step B02) The controller determines the water flow range into which the inlet water flow falls with a period T1 to obtain the water pump gear corresponding to the inlet water flow.

[0054] Step B03) If the current gear of the water pump is different from the water pump gear corresponding to the current inlet water flow, adjust the water pump gear to the water pump gear corresponding to the current inlet water flow; otherwise, wait for the next period and return to the previous step to execute.

[0055] By associating the gear position with the water inlet flow rate range, the pump speed is matched with the water inlet flow rate, avoiding the situation where, due to a relatively low water inlet flow rate and a relatively high pump speed, some air is sucked in, resulting in an idling phenomenon, or where, due to a relatively high water inlet flow rate and a relatively low pump speed, the hot water supply is insufficient.

[0056] There is an overlapping area among several water flow rate ranges stored in the controller. If the current water inlet flow rate is in the overlapping area, the pump gear position is locked. Locking the gear position in the overlapping area avoids frequent gear shifting of the pump when the water inlet flow rate fluctuates at the interval boundary, which affects the service life of the pump.

[0057] The controller calculates the change rate of the water inlet flow rate within a preset duration. If the change rate of the water inlet flow rate exceeds the preset threshold, then when the water inlet flow rate is in the overlapping area, the pump gear position is changed. Conversely, if the change rate of the water inlet flow rate does not exceed the preset threshold, then when the water inlet flow rate is in the overlapping area, the pump gear position is locked. By examining the change rate of the water inlet flow rate, when the change rate exceeds the preset threshold, the gear shifting of the pump can actively follow the rapid change of the water inlet flow rate, improving the temperature stability of the outlet water and enhancing the user experience.

[0058] In this embodiment, preferably, the set water flow rate ranges are the interval [3, 4], the interval (4, 5], and the interval (5, 6]. The unit of the water flow rate range is L / min, and the corresponding pump gear positions are gears 1 to 3. The period T1 is 10 seconds.

[0059] After the water pump boost is turned on, the controller periodically detects the outlet water temperature and finely adjusts the water pump speed according to the outlet water temperature. Please refer to the appendix Figure 3 , which specifically includes the following steps:

[0060] Step C01) The controller reads the outlet water temperature at a period T2.

[0061] Step C02) If the temperature rises by more than the preset first amplitude threshold, the water pump speed is increased by a preset step size.

[0062] Step C03) If the temperature drops by more than the preset second amplitude threshold, the water pump speed is decreased by a preset step size. Fine-tuning the water pump speed can better keep the outlet water temperature within a stable range and enhance the user experience.

[0063] The gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, the outlet water temperature, the water inlet flow rate, the proportional valve opening, and the inlet gas flow rate, and finely adjusts the water pump speed according to the inlet water temperature, the outlet water temperature, the water inlet flow rate, the proportional valve opening, and the inlet gas flow rate. Please refer to the appendix Figure 4 , which specifically includes the following steps:

[0064] Step D01) The controller reads the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening degree, and inlet air flow rate at a cycle T2.

[0065] Step D02) Calculate the heat required for water heating according to the outlet water temperature and inlet water temperature set by the user, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the outlet water temperature set by the user, and T_in is the inlet water temperature.

[0066] Step D03) Calculate the heat Q_fuel required to be provided by gas according to Q_water, Q_fuel = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_fuel.

[0067] Step D04) When the outlet water temperature exceeds the outlet water temperature set by the user, increase the water pump speed by a preset step; when the outlet water temperature is lower than the outlet water temperature set by the user, decrease the water pump speed by a preset step.

[0068] The inlet water flow rate is obtained by calculating the water pump speed. The water pump speed represents the water pump flow rate. Theoretically, the water pump flow rate should be equal to the inlet water flow rate. However, due to the presence of air in the inlet pipe, the actual water intake is lower than the theoretical water intake. At this time, the water temperature coming out of the heat exchanger will be higher than expected, and then the outlet water temperature will rise. The actual inlet water flow rate can be calculated inversely according to the outlet water temperature value, so as to finely adjust the water pump speed.

[0069] After the water pump is pressurized and started, the controller periodically detects the outlet water temperature and adjusts the fan speed according to the outlet water temperature, which specifically includes the following steps: The controller reads the outlet water temperature at a cycle T2; if the temperature rises and exceeds the preset first amplitude threshold, decrease the fan speed by a preset step; if the temperature drops and exceeds the preset second amplitude threshold, increase the fan speed by a preset step.

[0070] The gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening degree, and inlet air flow rate, and adjusts the fan speed according to the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening degree, and inlet air flow rate. Please refer to the appendix Figure 5 , which specifically includes the following steps:

[0071] Step E01) The controller reads the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening degree, and inlet air flow rate at a cycle T2.

[0072] Step E02) Calculate the heat required for water heating according to the outlet water temperature and inlet water temperature set by the user, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the outlet water temperature set by the user, and T_in is the inlet water temperature.

[0073] Step E03) Calculate the heat Q_fuel required to be provided by the gas according to Q_water, Q_fuel = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_fuel;

[0074] Step E04) When the outlet water temperature exceeds the outlet water temperature set by the user, decrease the fan speed in a preset step; when the outlet water temperature is lower than the outlet water temperature set by the user, increase the fan speed in a preset step.

[0075] By finely adjusting the fan speed, dynamically reduce the heat released by gas combustion, and combined with the fine adjustment of the water pump, make the actual water inflow more stable and the outlet water temperature more stable at the same time.

[0076] The beneficial technical effects of this embodiment include: By checking the inlet water flow and outlet water temperature before turning on the booster pump, it is avoided that when the inlet water flow is low, the water pump runs idly, affecting the service life of the water pump, and at the same time, it is avoided that a large amount of air is contained in the inlet water, resulting in too high a water temperature rise under the same gas heating, leading to a poor user experience; By dynamically adjusting the gear of the water pump after boosting, the supply of hot water is adapted to the inlet water flow; By finely adjusting the water pump speed and the fan speed, the water temperature is made more stable.

[0077] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the drawings and the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A control method for a water pump of a gas water heater, the gas water heater comprising a boost button, a controller, a blower, a gas proportional valve, an inlet water flow sensor, an outlet water flow sensor, an inlet water temperature sensor, and an outlet water temperature sensor, the inlet water flow sensor detecting the inlet water flow at the water inlet, the outlet water flow sensor detecting the outlet water flow at the water outlet, the inlet water temperature sensor and the outlet water temperature sensor respectively detecting the inlet water temperature at the water inlet and the outlet water temperature at the water outlet, characterized in that, It includes the following steps: The controller periodically detects whether the boost button is pressed. If it is pressed, it proceeds to the next step; otherwise, this step is repeated. The controller reads the inlet water flow sensor and the outlet water temperature sensor. If the inlet water flow is within the preset flow range and the outlet water temperature is lower than the preset first threshold, the controller starts the water pump for boosting and proceeds to the next step; otherwise, no operation is performed. After starting the water pump for boosting, the controller periodically detects the inlet water flow and adjusts the water pump speed gear according to the inlet water flow. Specifically, it includes the following steps: Several preset water flow ranges are stored in the controller, and each water flow range corresponds to a water pump gear. The controller determines the water flow range into which the inlet water flow falls with a period of T1, and obtains the water pump gear corresponding to the inlet water flow. If the current gear of the water pump is different from the water pump gear corresponding to the current inlet water flow, the water pump gear is adjusted to the water pump gear corresponding to the current inlet water flow; otherwise, it waits for the next period and returns to the previous step for execution. There is an overlap area between several water flow ranges stored in the controller. The controller calculates the change rate of the inlet water flow within a preset duration. If the change rate of the inlet water flow exceeds the preset threshold, the water pump gear is changed when the inlet water flow is in the overlap area; otherwise, if the change rate of the inlet water flow does not exceed the preset threshold, the water pump gear is locked when the inlet water flow is in the overlap area. After starting the water pump for boosting, the controller periodically detects the outlet water temperature and the inlet water flow. If the outlet water temperature exceeds the preset second threshold or the inlet water flow is less than the preset flow threshold, the controller controls the water pump to stop boosting and returns to the first step; otherwise, it waits for the preset duration and then re-executes this step.

2. The method for controlling a water pump of a gas water heater according to claim 1, wherein The water flow ranges are the interval [3, 4], the interval (4, 5], and the interval (5, 6]. The unit of the water flow range is L / min, and the corresponding water pump gears are from gear 1 to gear 3 respectively.

3. The method for controlling a water pump of a gas water heater according to any one of claim 1, wherein The period T1 is 10 seconds.

4. The method for controlling a water pump of a gas water heater according to claim 1, wherein After starting the water pump for boosting, the controller periodically detects the outlet water temperature and finely adjusts the water pump speed according to the outlet water temperature. Specifically, it includes the following steps: The controller reads the outlet water temperature with a period of T2. If the temperature rises by more than the preset first amplitude threshold, the water pump speed is increased by a preset step size. If the temperature drops by more than the preset second amplitude threshold, the water pump speed is decreased by a preset step size.

5. The method for controlling a water pump of a gas water heater according to claim 4, wherein The gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, the outlet water temperature, the inlet water flow, the proportional valve opening, and the inlet gas flow, and finely adjusts the water pump speed according to the inlet water temperature, the outlet water temperature, the inlet water flow, the proportional valve opening, and the inlet gas flow. Specifically, it includes the following steps: The controller reads the inlet water temperature, the outlet water temperature, the inlet water flow, the proportional valve opening, and the inlet gas flow with a period of T2. According to the set outlet water temperature and inlet water temperature of the user, calculate the heat required for water heating, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the set outlet water temperature of the user, and T_in is the inlet water temperature; Calculate the heat Q_gas required to be provided by gas according to Q_water, Q_gas = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_gas; When the outlet water temperature exceeds the set outlet water temperature of the user, increase the water pump speed in a preset step. When the outlet water temperature is lower than the set outlet water temperature of the user, decrease the water pump speed in a preset step.

6. A method for controlling a water pump of a gas water heater according to claim 1, characterized in that After the water pump is turned on for pressurization, the controller periodically detects the outlet water temperature and adjusts the fan speed according to the outlet water temperature. The specific steps are as follows: The controller reads the outlet water temperature at a period T2; If the temperature rises by more than a preset first amplitude threshold, decrease the fan speed in a preset step; If the temperature drops by more than a preset second amplitude threshold, increase the fan speed in a preset step.

7. A method for controlling a water pump of a gas water heater according to claim 6, characterized in that The gas water heater is also equipped with a fan speed sensor. The fan speed sensor detects the fan speed. The controller periodically detects the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and intake air flow rate, and adjusts the fan speed according to the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and intake air flow rate. The specific steps are as follows: The controller reads the inlet water temperature, outlet water temperature, inlet water flow rate, proportional valve opening, and intake air flow rate at a period T2; According to the set outlet water temperature and inlet water temperature of the user, calculate the heat required for water heating, Q_water = C * inlet water flow rate * (T_set - T_in), where Q_water is the heat required for water heating, C is the specific heat capacity of water, T_set is the set outlet water temperature of the user, and T_in is the inlet water temperature; Calculate the heat Q_gas required to be provided by gas according to Q_water, Q_gas = Q_water / η, where η is the preset heat exchange efficiency, and determine the fan speed according to Q_gas; When the outlet water temperature exceeds the set outlet water temperature of the user, decrease the fan speed in a preset step. When the outlet water temperature is lower than the set outlet water temperature of the user, increase the fan speed in a preset step.

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