Gas water heater and control method thereof

Abstract

The embodiment of the invention provides a gas water heater and a control method of the gas water heater. The gas water heater comprises a water path, a water flow detection device, a heating device, a gas adjusting valve, a gas pipeline and a controller. Wherein the fuel gas pipeline is used for conveying fuel gas to the heating device. The gas adjusting valve and the heating device are sequentially connected to the gas pipeline in series in the gas flow direction. The water flow detection device is arranged on the water path, and the heating device is used for heating water flow in the water path. The controller controls the booster pump and the gas regulating valve according to a water flow signal from the water flow detection device so as to start a waterfall washing mode, the booster pump is used for being connected with a water path, and when the gas water heater works in the waterfall washing mode, the output water flow of the gas water heater is larger than the rated water flow. The technical scheme is more convenient, safer and higher in reliability.

Description

Technical Field

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

[0002] With the development of the times, people's requirements for bathing are getting higher and higher. Water heaters used for bathing can be divided into electric water heaters, gas water heaters, solar water heaters, etc. according to different energy sources. According to the heating method, they can be divided into instant water heaters and storage water heaters.

[0003] The gas water heater includes a water circuit, a gas pipeline and a heating device. The gas pipeline is connected to the heating device and is used to transport gas to the heating device. A gas regulating valve may be provided on the gas pipeline to adjust the ventilation volume in the gas pipeline. The water in the water circuit is heated by burning the gas in the heating device. In usage scenarios such as homes, gas water heaters are generally installed in the kitchen to be as close as possible to the municipal gas pipeline in the home, while the user takes a bath in the bathroom. As a result, the user needs to leave the bathroom and come to the kitchen to change the working condition of the gas water heater. Some gas water heaters provide a communication device. Via the communication device, the user can remotely control the switching of the working mode of the gas water heater through smart devices such as mobile phones.

[0004] Although remote control based on communication devices brings certain conveniences, it requires users to operate their mobile phones while bathing, which is not only inconvenient to operate and easy to damage the mobile phone, but also very inconvenient for the elderly and children, and the user experience is poor. Summary of the invention

[0005] In order to at least partially solve the problems existing in the prior art, according to one aspect of the present invention, there is provided a gas water heater, comprising: a water circuit; a water flow detection device arranged on the water circuit; a heating device for heating the water flow in the water circuit; a gas regulating valve; a gas pipeline for conveying gas to the heating device, wherein the gas regulating valve and the heating device are sequentially connected in series on the gas pipeline along the air flow direction; and a controller for controlling a booster pump and a gas regulating valve according to a water flow signal from the water flow detection device, so as to control the gas water heater to start a waterfall mode, wherein the booster pump is used to connect the water circuit, and when the gas water heater operates in the waterfall mode, the output water flow of the gas water heater is greater than the rated water flow.

[0006] In the above technical solution, the booster pump and the gas regulating valve are controlled by detecting the water flow signal in the water circuit of the gas water heater, and the waterfall mode is remotely turned on before or during bathing. This can conveniently provide users with hot water greater than the rated water flow, significantly improving the user's bathing experience. Compared with controlling the gas water heater through other remote control devices or smart devices, the above operation is more convenient and safer, more reliable, and more suitable for people such as the elderly and children.

[0007] Exemplarily, the controller controls the booster pump and the gas regulating valve according to the water flow signal from the water flow detection device to control the gas water heater to start the waterfall mode, including the following operations: when a first preset condition is met, the gas regulating valve and the booster pump are controlled so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow rate is greater than the rated water flow rate to start the waterfall mode; wherein the first preset condition includes: the water flow signal indicates that the water flow flows again after being interrupted a first preset number of times within a first preset time.

[0008] In the above technical solution, the waterfall mode is turned on by using a water flow signal to indicate that the water flows again after being interrupted for a first preset number of times within a first preset time. This not only makes it convenient for users to turn on the waterfall mode by simply operating the faucet, but also prevents users from accidentally triggering the waterfall function during normal use of the gas water heater, thereby greatly improving the reliability of control.

[0009] Exemplarily, the water flow detection device includes a flow meter, and the first preset condition also includes: before a third moment, a water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time.

[0010] In the above technical solution, after determining that the water flow rate is stable based on the water flow signal, it is determined whether the water flow signal indicates that the water flow is interrupted for a first preset number of times within a first preset time. This can effectively prevent the user from accidentally turning on the waterfall mode due to daily water use, and thus avoid unnecessary calculations, which is easy to implement and not prone to errors.

[0011] Exemplarily, the controller is also used to perform a first timing operation from each first moment or second moment to determine whether the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range within at least a second preset time thereafter; wherein, the third flow threshold is within the preset flow range, the first moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range, and the second moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

[0012] In the above technical solution, whenever the water flow in the water channel changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit of the preset flow range, or the water flow changes from greater than the upper limit of the preset flow range to less than or equal to the upper limit and greater than or equal to the lower limit of the preset flow range, the stability of the water flow is timed. Therefore, when the water flow is too large or too small, no relevant logic calculation is performed, which reduces the amount of calculation while ensuring that the burst washing mode is accurately started according to the user's wishes.

[0013] Exemplarily, the water flow detection device includes a flow meter. When the water flow signal of the flow meter indicates that the water flow rate is less than a first flow threshold, the water flow is determined to be interrupted; when the water flow signal of the flow meter indicates that the water flow rate is greater than a second flow threshold, the water flow is determined to be flowing.

[0014] In the above technical solution, the first flow threshold and the second flow threshold are used to determine whether the water flow in the water path is interrupted or flowing according to the water flow signal. This can effectively prevent interference factors in the water path and circuit from affecting the controller's accurate judgment of whether the water flow in the water path is interrupted or not. This improves the reliability of detection and avoids the occurrence of false triggering of the waterfall mode.

[0015] Exemplarily, the water flow detection device includes a high-pressure switch. When the high-pressure switch is turned off, it is determined that the water flow is interrupted; when the high-pressure switch is turned on, it is determined that the water flow is flowing.

[0016] In the above technical solution, the gas water heater can detect whether the water flow in the water path is interrupted or not only through the high-pressure switch, which has low cost and simple control logic.

[0017] Exemplarily, the controller is also used to control the gas water heater to exit the waterfall mode when the water flow signal indicates that the water flow is interrupted for a third preset time.

[0018] In the above technical solution, based on the water flow signal indicating that the water flow is interrupted for the third preset time, the gas water heater is controlled to exit the waterfall mode. The exit from the waterfall mode also does not require the operation of smart devices such as mobile phones, which is safe and reliable. When the user forgets to actively exit the waterfall mode, the gas water heater will automatically exit the waterfall mode if no water is used for a period of time.

[0019] Exemplarily, the gas water heater also includes a fan for blowing air into the heating device; the controller is also used to control the speed of the fan according to the opening of the gas regulating valve, wherein the speed of the fan is positively correlated with the opening of the gas regulating valve.

[0020] In the above technical solution, the controller controls the speed of the fan according to the opening of the gas regulating valve. Thus, on the one hand, it ensures that the gas in the heating device of the gas water heater can burn smoothly, thereby ensuring that the gas water heater can output hot water at a large flow rate, and further ensuring that the gas water heater continues to work in the waterfall mode. On the other hand, a large amount of waste gas generated by gas combustion is effectively discharged.

[0021] Exemplarily, the gas water heater also includes a temperature sensor arranged at the water inlet of the water circuit; the controller is also used to: when the gas water heater is operating in the waterfall mode, determine whether the water flow at the current flow rate of the rated heat load can reach the preset temperature after being heated by the heating device; when the rated heat load can make the water flow at the current flow rate reach the preset temperature, control the opening of the gas regulating valve and the working power of the booster pump, so that the water flow at the current flow rate can flow out of the gas water heater at the preset temperature; when the rated heat load cannot make the water flow at the current flow rate reach the preset temperature, control the gas regulating valve to be fully opened and control the booster pump to stop working, so as to control the gas water heater to exit the waterfall mode.

[0022] In the above technical solution, the controller can automatically determine whether the outlet water temperature can reach the user's preset temperature under the current flow rate. Therefore, when the gas water heater works in the waterfall mode, it automatically controls the operation of various components of the gas water heater in the waterfall mode or exits the waterfall mode, avoiding a bad user experience.

[0023] Exemplarily, the controller is also used to control the gas water heater to start the zero cold water mode when a second preset condition is met; wherein the second preset condition includes: the water flow signal indicates that the water flow flows again after being interrupted a second preset number of times within a fourth preset time.

[0024] In the above technical solution, the zero cold water mode is turned on by using a water flow signal to indicate that the water flows again after being interrupted for the second preset number of times within the fourth preset time. This not only makes it convenient for users to turn on the zero cold water mode by simply operating the faucet, but also avoids the situation where users accidentally trigger the zero cold water function during normal use of the gas water heater, thereby greatly improving the reliability of control.

[0025] According to another aspect of the present invention, a control method for a gas water heater is also provided. The gas water heater comprises: a water circuit, a water flow detection device arranged on the water circuit, a heating device for heating the water flow in the water circuit, a gas regulating valve, and a gas pipeline for conveying gas to the heating device, wherein the gas regulating valve and the heating device are sequentially connected in series on the gas pipeline along the air flow direction. The control method for the gas water heater comprises: according to the water flow signal from the water flow detection device, controlling the booster pump and the gas regulating valve to control the gas water heater to start the waterfall mode, wherein the booster pump is used to connect the water circuit, and when the gas water heater works in the waterfall mode, the output water flow of the gas water heater is greater than the rated water flow.

[0026] Exemplarily, based on the water flow signal from the water flow detection device, the booster pump and the gas regulating valve are controlled to control the gas water heater to start the waterfall mode, including: when a first preset condition is met, the gas regulating valve and the booster pump are controlled so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow rate is greater than the rated water flow rate, so as to start the waterfall mode; wherein the first preset condition includes: the water flow signal indicates that the water flow flows again after being interrupted for a first preset number of times within a first preset time.

[0027] Exemplarily, the water flow detection device includes a flow meter, and the first preset condition also includes: before a third moment, a water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time.

[0028] Exemplarily, the control method also includes: starting from each first moment or second moment, executing a first timing operation to determine whether the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range within at least a second preset time thereafter; wherein, the third flow threshold is within the preset flow range, the first moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range, and the second moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

[0029] Exemplarily, the control method further includes: when the water flow signal indicates that the water flow is interrupted for a third preset time, controlling the gas water heater to exit the waterfall mode.

[0030] A series of simplified concepts are introduced in the summary of the invention, which will be further described in detail in the detailed description. The summary of the invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0031] The advantages and features of the present invention are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,

[0033] Figure 1 is a schematic block diagram of a gas water heater according to an exemplary embodiment of the present invention;

[0034] Figure 2The figure is a flow chart of a method for controlling a gas water heater according to an exemplary embodiment of the present invention.

[0035] The above drawings include the following reference numerals:

[0036] 10. Water inlet; 20. Water outlet; 30. Gas inlet; 100. Water channel; 110. Booster pump; 120. Flow meter; 200. Gas pipeline; 210. Gas regulating valve; 220. Heating device; 221. Burner; 222. Heat exchanger; 300. Controller. DETAILED DESCRIPTION

[0037] In the following description, a large amount of details are provided so that the present invention can be thoroughly understood. However, it will be appreciated by those skilled in the art that the following description only exemplarily illustrates a preferred embodiment of the present invention, and the present invention can be implemented without one or more such details. In addition, in order to avoid confusion with the present invention, some technical features well known in the art are not described in detail.

[0038] In order to fully understand the embodiments of the present invention, detailed structures will be presented in the following description. Obviously, the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0039] An embodiment of the present invention provides a gas water heater. Figure 1 A schematic block diagram of a gas water heater according to an exemplary embodiment of the present invention is shown. The gas water heater may include a water circuit 100. The water circuit 100 may have a cold water inlet 10, and the cold water inlet 10 is used to connect to a municipal water circuit. The water flow may be heated in the water circuit 100. The water circuit 100 may also have a hot water outlet 20, which is used to connect to external pipes in the user's home, such as water pipes. When the user turns on the water use end, hot water may flow out from the hot water outlet 20 for the user to use. A water flow detection device may also be provided on the water circuit 100. The water flow detection device may be one or more of a pressure sensor, a flow meter, and the like. Exemplarily, the water flow detection device may be used to detect a specific flow rate of water in the water circuit 100, such as 8 liters per minute (L / min). Alternatively, the water flow detection device may also be used to detect whether the water in the water circuit 100 is flowing. In Figure 1 In the specific embodiment shown, the water flow detection device may include a flow meter 120. The water flow signal generated by the flow meter 120 may include water flow information. When the water flow is less than the flow threshold, it can be considered that the water flow is interrupted, that is, it is not flowing. The water path 100 may also include a segment valve. The segment valve can adjust the delivery flow of cold water in the water path 100.

[0040] The gas water heater may further include a gas pipeline 200 and a heating device 220. The gas pipeline 200 is connected to the gas inlet 30 of the gas water heater and is used to deliver gas to the heating device 220. The heating device 220 is used to heat the water flow in the water path 100 using the gas. The heating device 220 can convert the chemical energy of the gas into thermal energy to heat the cold water in the water path 100. The heating device 220 may include a burner 221 and a heat exchanger 222. The gas burns in the burner 221 to generate heat. The water path 100 passes through the heat exchanger 222, and the heat exchanger 222 transfers the heat to the cold water in the water path 100. A gas regulating valve 210 may be provided on the gas pipeline 200. The gas regulating valve 210 and the heating device 220 are sequentially connected in series on the gas pipeline 200 along the gas flow direction. In other words, the gas regulating valve 210 is upstream of the heating device 220. The gas regulating valve 210 may include a proportional valve. The proportional valve can adjust the delivery flow of gas and air, thereby adjusting the amount of gas burned per unit time in the burner 221, and further adjusting the thermal power output by the burner 221.

[0041] The gas water heater may further include a controller 300, which is connected to the water flow detection device, the booster pump 110 and the gas regulating valve 210. The controller 300 may be used to control the booster pump 110 and the gas regulating valve 210 according to the water flow signal from the water flow detection device, so as to control the gas water heater to start the waterfall mode. The controller 300 may be implemented using various chips, such as a field programmable gate array (FPGA), a microprocessor (MPU), a programmable logic controller (PLC), a microprocessing unit (MCU), etc.

[0042] The booster pump 110 is used to connect to the waterway 100 to increase the pressure of the water flow in the waterway 100. Figure 1 As shown, the booster pump 110 can be used as a part of the gas water heater and arranged in the housing of the gas water heater. The booster pump 110 can also be arranged on the external pipeline of the gas water heater. It can be understood that the booster pump 110 is connected to the waterway 100 and can pressurize the water flow in the waterway 100. The booster pump 110 can be various booster water pumps currently available or developed in the future, such as a single-pipe booster pump, a DC booster pump, or a self-priming whole-house booster pump.

[0043] When the controller 300 determines that the water flow signal of the water flow detection device has a specific feature, the booster pump 110 can be controlled to work and the gas regulating valve 210 can be controlled to increase the thermal power output by the burner 221. As a result, the output water flow of the gas water heater is greater than the rated water flow, and its waterfall mode is turned on. For example, the gas water heater can be provided with at least two working modes: normal and waterfall. When the gas water heater works in the normal mode, its output water flow is less than or equal to the rated water flow. When the gas water heater works in the waterfall mode, its output water flow is greater than the rated water flow, and it can quickly provide a large amount of hot water for users to use. When, for example, the user needs to use hot water at multiple points at the same time or a large amount of hot water at a single point, the user can choose the waterfall mode. Exemplarily, the specific features of the above-mentioned water flow signal can be set in advance, for example, the water flow signal can represent a specific flow mode of the water flow, for example: water flow interruption-water flow flows again-water flow interruption again-water flow flows again. When the controller 300 determines that the water flow signal has a specific feature, the waterfall mode of the gas water heater can be turned on. The controller 300 can control the booster pump 110 to pressurize the water flow in the waterway 100 with a first head greater than its rated head. For example, the controller 300 can provide the booster pump 110 with an input current exceeding its rated current to control the output power of the booster pump 110, thereby controlling the booster pump 110 to pressurize the water flow in the waterway 100 with the first head. In one example, the rated water flow of the gas water heater is 12L / min, and in its waterfall mode, under the action of the booster pump 110 working at the first head, its output water flow can reach 16L / min. Preferably, in the waterfall mode, the water flow rate is 20%-100% greater than the water flow rate in the normal mode. It can be understood that as the output water flow of the gas water heater increases, in order to make the water reach the desired temperature, the heat load of the gas water heater also increases accordingly. The desired temperature can be a temperature pre-set by the user using an input device, such as 60 degrees. In order to increase the heat load of the gas water heater, the controller 300 can also control the gas proportional valve to work under the first working condition. For example, the controller 300 can provide a larger input current to the gas proportional valve to increase the opening of the gas proportional valve, thereby increasing the gas flow in the gas pipeline and increasing the thermal power of the heating device 220 of the gas water heater. By using the controller 300 to control the booster pump 110 and the gas regulating valve 210 according to the water flow signal, the gas water heater can enter the waterfall mode as desired.

[0044] In the above technical solution, the booster pump 110 and the gas regulating valve 210 are controlled by detecting the water flow signal in the water path 100 of the gas water heater, and the waterfall mode is remotely turned on before or during bathing. This can conveniently provide users with hot water greater than the rated water flow, significantly improving the user's bathing experience. Compared with controlling the gas water heater through other remote control devices or smart devices, the above operation is more convenient and safer, more reliable, and more suitable for people such as the elderly and children.

[0045] Exemplarily, the controller 300 controls the booster pump 110 and the gas regulating valve 210 according to the water flow signal from the water flow detection device to control the gas water heater to start the waterfall mode, including the following operations: when a first preset condition is met, the gas regulating valve 210 and the booster pump 110 are controlled so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow rate is greater than the rated water flow rate, so as to start the waterfall mode. The preset condition includes: the water flow signal indicates that the water flow flows again after being interrupted for a first preset number of times within a first preset time.

[0046] During the operation of the gas water heater, the controller 300 can determine in real time whether the current first preset condition has been met. In one example, the first preset time is 5 seconds and the first preset number of times is 2 times. When the user is taking hot water from the gas water heater, the controller 300 can first determine whether the water flow signal generated by the water flow detection device indicates that the water flow in the waterway 100 is interrupted, that is, the water flow in the waterway 100 no longer flows. It can be understood that the interruption of the water flow in the waterway 100 may be triggered by the user turning off the faucet. After determining that the water flow is interrupted for the first time according to the water flow signal, the second timing operation can be started. According to the situation of the water flow signal, the second timing operation can last up to the first preset time. After determining that the water flow is interrupted for the first time according to the water flow signal, the controller 300 starts the second timing operation. Thereafter, the water flow signal in the waterway 100 may indicate that the water flow in the waterway 100 flows again. The flow of water in the waterway 100 may be triggered by the user turning on the faucet. After the water flow flows again, when the user turns off the faucet again, the water flow signal may indicate that the water flow is interrupted for the second time. Afterwards, if the water flow signal indicates that the water flow flows again after the second interruption, the waterfall mode is turned on and the second timing operation is stopped. In other words, in the above process, the user may sequentially perform the operations of closing the faucet, opening the faucet, closing the faucet again, and opening the faucet again, thereby turning on the waterfall mode. In other examples, when the time counted by the second timing operation reaches 5 seconds, but the water flow signal does not indicate that the water flow flows again after being interrupted twice within 5 seconds, the waterfall mode is not turned on and the second timing operation is restarted. For example, the user may simply want to turn off the faucet after bathing, so the controller 300 only determines the first interruption of the water flow within 5 seconds according to the water flow signal. For another example, the user may turn off the faucet and then turn on the faucet to restart the bath. Then the controller 300 determines that the water flow flows again after the first interruption within 5 seconds according to the water flow signal. In these examples, when the time counted by the second timing operation reaches 5 seconds, no operation to change the working condition of the booster pump 110 is performed, and the gas proportional valve is controlled to work in normal mode, and the above second timing operation is restarted. Of course, the first preset time and the first preset number of times can be adjusted as needed. The first preset time and the first preset number of times can be set in the controller 300 during production, or can be set by the customer. The first preset time is usually not set too long. The first preset time is usually 2-10 seconds. It can be understood that if the first preset time is too long, the user is likely to mistakenly trigger the waterfall mode during normal use; if the first preset time is too short, the user may not have time to perform a specific operation to turn on the waterfall mode. The first preset number of times should not be set too few, usually set to 2-5 times, also to prevent false triggering. If the first preset number of times is set too much, it may make it too difficult to turn on the waterfall mode, affecting the user experience.

[0047] In the above technical solution, the waterfall mode is turned on by using a water flow signal to indicate that the water flows again after being interrupted for a first preset number of times within a first preset time. This not only makes it convenient for users to turn on the waterfall mode by simply operating the faucet, but also prevents users from accidentally triggering the waterfall function during normal use of the gas water heater, thereby greatly improving the reliability of control.

[0048] Exemplarily, the water flow detection device may include a flow meter 120, which is electrically connected to the controller 300. The water flow signal generated by the flow meter 120 includes relatively accurate and quantified flow information. The flow meter 120 may include one or more flow meters such as a magnetic flow meter, a volumetric flow meter, a rotor flow meter, etc. The above-mentioned first preset condition may also include: before the third moment, the water flow signal of the flow meter 120 indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time. Similar to the first preset time, the second preset time may also be adjusted as needed. The second preset time may be set in the controller 300 during production, or may be set by the customer. The second preset time may be any value from 5 to 30 seconds.

[0049] In one example, the second preset time may be 10 seconds. The controller 300 starts timing when it determines that the water flow rate is within the preset flow range according to the water flow signal. If the water flow rate is always within the preset flow range when the counted time reaches 10 seconds, the timing is stopped and it is determined whether the water flow signal indicates that the water flow is interrupted for the first preset number of times within the first preset time and then flows again. It can be understood that within the 10 seconds, the water flow rate can fluctuate as long as it fluctuates within the preset flow range. In this way, any moment after the counted time reaches 10 seconds can be used as the starting moment for determining whether the water flow is interrupted for the first preset number of times within the first preset time and then flows again, that is, the third moment. If the water flow rate exceeds the preset flow range when the counted time has not reached 10 seconds, the timing is stopped and the water flow rate is waited to return to the preset flow range to start timing again. It can be understood that the hot water output from the water outlet 20 of the gas water heater may be supplied to multiple water points. In daily water use, it may occur that the output water flow rate of the gas water heater is adjusted multiple times in a short period of time, and the faucets of different water points are turned on and off multiple times. These situations may cause the false triggering of the waterfall mode, causing inconvenience to the user. By way of example and not limitation, an error of 4 L / min can be set, and the flow rate indicated by the current water flow signal is within the range of the preset flow rate of 8 L / min ± 4 L / min, that is, any value between 4 L / min and 12 L / min, and the current water flow rate in the waterway 100 can be considered to be stable. After the water flow rate is stable, a judgment operation is performed to determine whether the water flow signal has a specific feature to further determine whether to start the waterfall washing mode.

[0050] In the above technical solution, after determining that the water flow rate is stable based on the water flow signal, it is determined whether the water flow signal indicates that the water flow is interrupted for a first preset number of times within a first preset time. This can effectively prevent the user from accidentally turning on the waterfall mode due to daily water use, and thus avoid unnecessary calculations, which is easy to implement and not prone to errors.

[0051] Due to the existence of the error, it is possible to determine whether the water flow signal indicates that the water flow flows at a flow rate within the preset flow range for at least the second preset time when the measured current flow rate is greater than or equal to the median value of the preset flow range. Exemplarily, the controller 300 is also used to perform a first timing operation from each first moment or second moment to determine whether the water flow signal of the flow meter 120 indicates that the water flow flows at a flow rate within the preset flow range for at least the second preset time thereafter. The third flow threshold is within the preset flow range. For example, it is the median value of the preset flow range. When the third flow threshold is the median value within the preset flow range, the allowed flow fluctuation is large. The first moment is the moment when the water flow signal of the flow meter 120 indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range, and the second moment is the moment when the water flow signal of the flow meter 120 indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

[0052] The controller 300 is also used to determine whether the current moment is the aforementioned first moment or second moment before determining whether the water flow signal of the flow meter 120 indicates that the water flow flows at a flow rate within a preset flow range within at least a second preset time thereafter. The controller 300 can perform a first timing operation from each first moment or second moment. In this way, it can be determined whether the water flow signal of the flow meter 120 indicates that the water flow flows within a preset flow range, that is, a stable flow, within at least a second preset time after the first moment or the second moment. For example, the third flow threshold is 8L / min, the error is 4L / min, and the preset flow range is between 4L / min and 12L / min. After the gas water heater starts working, when the flow rate of the water flow in the waterway 100 is greater than or equal to 8L / min and less than 12L / min, the first timing operation is started. After the first timing operation is started, even if the flow rate is less than 8L / min, the first timing operation will not be stopped until the time counted by the first timing operation reaches the second preset time, then at this time, it can be determined whether the waterfall mode is turned on according to the water flow signal. This process has been described in detail above, and for the sake of brevity, it will not be repeated here. If the flow rate is less than the lower limit of the preset flow range of 4L / min or greater than the upper limit of the preset flow range of 12L / min, stop the first timing operation and wait for the next first moment or second moment to trigger the first timing operation to determine whether to turn on the waterfall washing mode.

[0053] In the above technical solution, whenever the water flow in the waterway 100 changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit of the preset flow range, or the water flow changes from greater than the upper limit of the preset flow range to less than or equal to the upper limit and greater than or equal to the lower limit of the preset flow range, the stability of the water flow is timed. Therefore, when the water flow is too large or too small, no relevant logic calculation is performed, which reduces the amount of calculation while ensuring that the burst washing mode is accurately started according to the user's wishes.

[0054] Exemplarily, in the example where the water flow detection device includes a flow meter 120, the controller 300 can determine whether the water flow is interrupted based on the water flow signal detected by the flow meter 120. Due to the presence of interference, if the water flow is strictly determined to be zero, the probability of misjudgment will increase. Therefore, when the water flow signal of the flow meter 120 indicates that the water flow rate is less than the first flow rate threshold, it is determined that the water flow is interrupted; on the other hand, when the water flow signal of the flow meter 120 indicates that the water flow rate is greater than the second flow rate threshold, it is determined that the water flow is flowing. The first flow rate threshold and the second flow rate threshold can be equal, or they can be set separately according to the actual use environment.

[0055] In the above technical solution, the first flow threshold and the second flow threshold are used to determine whether the water flow in the water path 100 is interrupted or flowing according to the water flow signal. This can effectively prevent interference factors in the water path 100 and the circuit from affecting the controller 300's accurate determination of whether the water flow in the water path 100 is interrupted or not. This improves the reliability of detection and avoids the occurrence of false triggering of the waterfall mode.

[0056] Not shown, the water flow detection device may include a high-voltage switch. When the high-voltage switch is closed, it is determined that the water flow is interrupted; when the high-voltage switch is opened, it is determined that the water flow is flowing. In an embodiment not shown, the controller may determine whether the user opens or closes the faucet based on the signal transmitted by the high-voltage switch. When the user closes the faucet, the water pressure in the water circuit increases, and the circuit connected to the high-voltage switch is closed; the opposite is true when the user opens the faucet. Of course, the high-voltage switch may also be a component that opens when in action and closes when in recovery, and the judgment logic of the controller is adjusted accordingly, which is not limited in detail here.

[0057] In the above technical solution, the gas water heater can detect whether the water flow in the water path 100 is interrupted or not only through the high-pressure switch, which has low cost and simple control logic.

[0058] Of course, the present application does not exclude the embodiment of simultaneously providing the flow meter 120 and the high-pressure switch as the water flow detection device. In such an embodiment, the water flow signals of the two can be combined to determine whether the water flow in the waterway 100 is interrupted. For example, only when both indicate that the water flow is interrupted, the controller determines that the water flow is interrupted; only when both indicate that the water flow is flowing, the controller determines that the water flow is flowing.

[0059] Exemplarily, the gas water heater further includes a temperature sensor disposed at the water inlet 10 of the water path 100. In some cases, the temperature of the water inlet to the water path 100 may vary with the seasons. In this case, the temperature sensor can be provided so that the controller 300 can more accurately control the booster pump 110 and the gas regulating valve 210 based on the temperature of the inlet water, so that the temperature of the outlet water reaches the user's preset temperature.

[0060] The controller 300 can also be used to: when the gas water heater is working in the waterfall mode, determine whether the water flow at the current flow rate of the rated heat load can reach the preset temperature after being heated by the heating device 220. When the rated heat load can make the water flow at the current flow rate reach the preset temperature, control the opening of the gas regulating valve 210 and the working power of the booster pump 110 so that the water flow at the current flow rate flows out of the gas water heater at the preset temperature. When the rated heat load cannot make the water flow at the current flow rate reach the preset temperature, control the gas regulating valve 210 to fully open and control the booster pump 110 to stop working, so as to control the gas water heater to exit the waterfall mode.

[0061] For example, when the inlet water temperature and the preset temperature are determined, the controller 300 can determine whether the water flow at the current flow rate can reach the preset temperature under the rated thermal load according to the following inequality, Q(T2-T1)N≤F1, where Q represents the current flow rate, T2 and T1 represent the outlet water temperature and the inlet water temperature respectively, N represents the compensation coefficient of the gas water heater, and F1 represents the rated thermal load of the gas water heater.

[0062] When the above inequality holds, the controller 300 determines that the rated heat load can make the current water flow reach the preset temperature, and it can control the opening of the gas regulating valve 210 and the working power of the booster pump 110. Thus, the water temperature output by the gas water heater is the preset temperature, and the water flow is greater than the rated water flow, which can meet the user's demand for showering.

[0063] When the above inequality does not hold, the controller 300 determines that the rated heat load cannot make the current flow of water reach the preset temperature. If the controller 300 turns on the waterfall mode at this time, the output water flow rate will further increase. This will result in hot water with a temperature lower than the set temperature being output even if the gas regulating valve 210 is fully open. This may be because the user's set temperature is too high, or the water inlet temperature is too low, or both. At this time, the waterfall mode will seriously affect the user experience. Therefore, in this case, the gas regulating valve 210 can be controlled to be fully opened and the booster pump 110 can be controlled to stop working to control the gas water heater to exit the waterfall mode.

[0064] In the above technical solution, the controller 300 can automatically determine whether the outlet water temperature under the current flow rate can reach the user's preset temperature. Thus, when the gas water heater works in the waterfall mode, it automatically controls the operation of various components of the gas water heater in the waterfall mode or exits the waterfall mode to avoid giving the user a bad experience.

[0065] Exemplarily, the gas water heater also includes a fan for blowing air into the heating device 220. The gas water heater uses gas as the energy for heating. During the combustion of the gas, oxygen is required and carbon dioxide, water vapor, etc. are produced. When the gas is not burned fully, toxic carbon monoxide may also be produced. Setting a fan is a relatively conventional solution to the above problem. The burner 221 of the heating device 220 may be provided with an air inlet, and the fan is arranged at the air inlet, which can pump air into the burner 221 and blow away the combustion exhaust gas at the same time. Alternatively, the burner may be provided with an air outlet, and the fan is arranged at the air outlet of the burner. The exhaust gas is taken away due to the negative pressure generated by the fan, and the air is sucked into the burner through the air inlet. In this way, the flame in the burner is not easily blown out by the fan. The controller 300 is also used to control the speed of the fan according to the opening of the gas regulating valve 210, wherein the speed of the fan is positively correlated with the opening of the gas regulating valve 210. It can be understood that when the opening of the gas regulating valve 210 increases, the exhaust gas generated will also increase accordingly. In particular, when the gas water heater is in the waterfall mode, the opening of the gas regulating valve 210 will also increase adaptively due to the increase in the output water flow. At this time, the speed of the fan can be appropriately increased according to the opening of the gas regulating valve 210, so that more exhaust gas can be discharged to avoid the accumulation of exhaust gas affecting the combustion efficiency or causing poisoning. Of course, when the opening of the gas regulating valve 210 decreases, the flame will also decrease. At this time, reduce the speed of the fan to avoid excessive convection in the burner, causing the flame to go out.

[0066] In the above technical solution, the controller 300 controls the speed of the fan according to the opening of the gas regulating valve 210. Thus, on the one hand, it is ensured that the gas in the heating device 220 of the gas water heater can burn smoothly, thereby ensuring that the gas water heater can output hot water at a large flow rate, thereby ensuring that the gas water heater continues to work in the waterfall mode. On the other hand, a large amount of waste gas generated by the combustion of gas is effectively discharged.

[0067] Exemplarily, the controller 300 is also used to control the gas water heater to exit the waterfall mode when the water flow signal indicates that the water flow is interrupted for a third preset time.

[0068] Since the waterfall mode consumes a lot of energy, turning it on for a long time not only wastes energy, but also may shorten the service life of the water heater. On the other hand, the waterfall mode will cause certain inconveniences in daily use due to its large water flow and high water pressure. Therefore, when the user does not need the waterfall mode, it is preferred to exit the waterfall mode in time. In one example, the third preset time can be 5 seconds. When the gas water heater is in the waterfall mode, the controller 300 can start the third timing operation from the moment when the water flow signal indicates that the water flow is interrupted. When the time counted by the third timing operation of the controller 300 reaches 5 seconds, and it is determined according to the water flow signal that the user has not reopened the faucet, the water flow in the waterway 100 is automatically exited after 5 seconds of interruption. When the time counted by the third timing operation has not reached 5 seconds, the controller 300 determines according to the water flow signal that the faucet is opened again, and the waterfall mode will not be exited. In other words, if the user still wants to continue the waterfall mode, as long as the faucet is opened again within 5 seconds of closing the faucet, it will not exit. At the same time, the 5-second buffer time can prevent the water flow from fluctuating due to water use by other equipment on the waterway 100, causing the gas water heater to exit the waterfall mode by mistake. Of course, the third preset time can also be 0 seconds, 10 seconds or 20 seconds. In other words, the gas water heater can exit the waterfall mode immediately after the user interrupts the bath, or it can wait for a longer time and exit the waterfall mode if no water use by the user is detected before the third timing operation ends. If the third preset time is too long, it will also cause inconvenience to the user. Preferably, the third preset time is any value within 5 to 20 seconds.

[0069] In the above technical solution, based on the water flow signal indicating that the water flow is interrupted for the third preset time, the gas water heater is controlled to exit the waterfall mode. This exit from the waterfall mode also does not require the operation of smart devices such as mobile phones, which is safe and reliable. When the user forgets to actively exit the waterfall mode, the gas water heater will automatically exit the waterfall mode if no water is used for a period of time. The reasonable setting of the third preset time can prevent the accidental exit from the waterfall mode during bathing, which is more humane.

[0070] Exemplarily, the controller 300 is also used to control the gas water heater to start the zero cold water mode when the second preset condition is met. In the zero cold water mode, the booster pump is turned on to circulate the water flow in the waterway between the user's water intake (such as a faucet) and the gas water heater, thereby ensuring that the user can get hot water as soon as the faucet is turned on. The second preset condition may include: the water flow signal indicates that the water flow is interrupted for a second preset number of times within a fourth preset time and then flows again. It can be understood that the second preset condition is similar to the aforementioned first preset condition, but not exactly the same. For example, the second preset number is different from the first preset number. For example, when the first preset number is 2, the second preset number can be 3. The fourth preset time can be the same as or different from the first preset time. In this way, the zero cold water mode can also be remotely started only by switching the faucet. When in use, it can be understood that when the faucet is turned on without turning on the zero cold water mode, a certain amount of cold water will be released because the zero cold water mode has not been turned on. However, if the zero cold water mode is turned on by the above operation at this time, the zero cold water mode can be maintained all the time. When taking hot water from the gas water heater in the future, cold water will not be released. There is no limitation on the method of shutting down the zero cold water mode, as long as it does not affect the user experience, and it may include but is not limited to button operation on the gas water heater, mobile phone software operation, etc.

[0071] In the above technical solution, the water flow signal indicates that the zero cold water mode is turned on by the water flow signal after the water flow is interrupted for the second preset number of times within the fourth preset time, which not only allows the user to turn on the zero cold water mode by simply operating the faucet, but also prevents the user from accidentally triggering the zero cold water function during normal use of the gas water heater, greatly improving the reliability of control. Finally, in the technical solution, the booster pump is reused in the waterfall mode and the zero cold water mode to improve the utilization rate of the equipment.

[0072] The present invention also discloses a control method for a gas water heater, which is applicable to the above-mentioned gas water heater. The gas water heater may include a water circuit 100, a water flow detection device, a heating device 220, a gas regulating valve 210 and a gas pipeline 200. The water flow detection device is arranged on the water circuit 100. The gas pipeline 200 is used to transport gas to the heating device 220. The heating device 220 is used to heat the water flow in the water circuit 100. The gas regulating valve 210 and the heating device 220 are sequentially connected in series on the gas pipeline 200 along the air flow direction.

[0073] The control method of the gas water heater may include: controlling the booster pump 110 and the gas regulating valve 210 according to the water flow signal from the water flow detection device to control the gas water heater to start the waterfall mode. The booster pump 110 is used to connect the water path 100. When the gas water heater works in the waterfall mode, the output water flow of the booster pump 110 is controlled to be greater than the rated water flow.

[0074] Exemplarily, the step of controlling the booster pump 110 and the gas regulating valve 210 according to the water flow signal from the water flow detection device may include: when a first preset condition is met, controlling the gas regulating valve 210 and the booster pump 110 so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow is greater than the rated water flow, so as to start the waterfall mode. The first preset condition may include: the water flow signal indicates that the water flow flows again after being interrupted for a first preset number of times within a first preset time.

[0075] Exemplarily, the water flow detection device includes a flow meter 120. The first preset condition may also include: before the water flow signal indicates a third moment, the water flow signal of the flow meter 120 indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time.

[0076] Exemplarily, the control method may further include: starting from each first moment or second moment, performing a first timing operation to determine whether the water flow signal of the flow meter 120 indicates that the water flows at a flow rate within a preset flow range within at least a second preset time thereafter. The third flow threshold is within the preset flow range. The first moment is the moment when the water flow signal of the flow meter 120 indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range. The second moment is the moment when the water flow signal of the flow meter 120 indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

[0077] Exemplarily, the control method may further include: when the water flow signal indicates that the water flow is interrupted for a third preset time, controlling the gas water heater to exit the waterfall mode.

[0078] Figure 2 FIG. 1 is a schematic flow chart of a method for controlling a gas water heater according to an embodiment of the present application. Figure 2As shown, after the gas water heater is turned on, it works in normal mode, and the user can take hot water of a preset temperature at a small flow rate (not greater than the rated flow rate). In this process, when the water flow signal of the flow meter 120 indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit of the preset flow range, the first timing operation is started. If the water flow does not last for at least the second preset time within the preset flow range, for example, the user turns down the flow or increases the flow, so that the flow is lower than the lower limit of the preset flow range or higher than the upper limit of the preset flow range, then when the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit of the preset flow range, or the water flow changes from greater than the upper limit of the preset flow range to less than or equal to the upper limit and greater than or equal to the lower limit, the first timing operation is restarted. If the water flow continues for at least the second preset time within the preset flow range according to the first timing operation, it is started to detect whether the water flow signal has a specific feature, such as the water flow can flow again after the first preset number of interruptions within the first preset time or the water flow can flow again after the second preset number of interruptions within the fourth preset time. In the following examples, the description is made by taking the case where the water flow is interrupted for the first preset number of times within the first preset time and then flows again as an example. For example, the controller 300 may start the second timing operation after detecting the water flow interruption. If, according to the second timing operation, the water flow interruption occurs for the first preset number of times within the first preset time, for example, the user switches the faucet on and off many times, it can be determined that the user has issued an instruction to start the waterfall mode. At this time, the booster pump 110 and the gas regulating valve 210 may be controlled to start the waterfall mode of the gas water heater. During the operation of the gas water heater in the waterfall mode, it may be determined whether the water flow of the current flow can reach the preset temperature under the rated heat load according to the current flow rate, the inlet water temperature and the preset temperature. If it can be reached, the waterfall mode is turned on. If it cannot be reached, the waterfall mode is exited. If, according to the second timing operation, the water flow interruption does not occur for the first preset number of times within the first preset time, then it is returned again to determine whether to execute the aforementioned first timing operation. When the time of the water flow interruption reaches the third preset time, the waterfall mode is exited. Specifically, during the operation of the gas water heater in the waterfall mode, the controller 300 may start the third timing operation after detecting the water flow interruption. If the water flow remains interrupted within the third preset time according to the third timing operation, the gas water heater is controlled to exit the waterfall mode.

[0079] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by directional words such as "front", "back", "up", "down", "left", "right", "lateral", "vertical", "vertical", "horizontal", "top", "bottom", etc. is usually based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention; the directional words "inside" and "outside" refer to the inside and outside relative to the contour of each component itself.

[0080] For ease of description, regional relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the regional positional relationship between one or more components or features shown in the figure and other components or features. It should be understood that regional relative terms include not only the orientation of the components as described in the figure, but also different orientations in use or operation. For example, if the components in the accompanying drawings are inverted as a whole, the components "above other components or features" or "above other components or features" will include the situation where the components are "below other components or structures" or "below other components or structures". Therefore, the exemplary term "above" may include both "above" and "below". In addition, these components or features may also be positioned at other different angles (e.g., rotated 90 degrees or other angles), and this article is intended to include all of these situations.

[0081] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, parts, components and / or combinations thereof.

[0082] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0083] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A gas water heater, characterized in that: include: waterway; A water flow detection device disposed on the waterway; A heating device for heating the water flow in the waterway; Gas regulating valve; A gas pipeline for conveying gas to the heating device, wherein the gas regulating valve and the heating device are sequentially connected in series on the gas pipeline along the gas flow direction; and A controller is used to control the booster pump and the gas regulating valve according to the water flow signal from the water flow detection device, so as to control the gas water heater to start the waterfall mode, wherein the booster pump is used to connect the water circuit, and when the gas water heater operates in the waterfall mode, the output water flow of the gas water heater is greater than the rated water flow.

2. The gas water heater according to claim 1, characterized in that: The controller controls the booster pump and the gas regulating valve according to the water flow signal from the water flow detection device to control the gas water heater to start the waterfall mode, including the following operations: When a first preset condition is met, the gas regulating valve and the booster pump are controlled so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow rate is greater than the rated water flow rate, so as to start the waterfall mode; Wherein, the first preset condition includes: the water flow signal indicates that the water flow starts to flow again after being interrupted for a first preset number of times within a first preset time.

3. The gas water heater according to claim 2, characterized in that: The water flow detection device comprises a flow meter, The first preset condition also includes: before a third moment, the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time.

4. The gas water heater according to claim 3, characterized in that: The controller is also used to perform a first timing operation from each first moment or second moment to determine whether the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range within at least a second preset time thereafter; Among them, the third flow threshold is within the preset flow range, the first moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range, and the second moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

5. The gas water heater according to claim 2, characterized in that: The water flow detection device comprises a flow meter, When the water flow signal of the flow meter indicates that the water flow rate is less than a first flow rate threshold, it is determined that the water flow is interrupted; When the water flow signal of the flow meter indicates that the water flow rate is greater than a second flow rate threshold, it is determined that the water flow is flowing.

6. The gas water heater according to claim 2, characterized in that: The water flow detection device comprises a high-voltage switch, When the high-pressure switch is turned off, it is determined that the water flow is interrupted; When the high pressure switch is turned on, it is determined that the water flows.

7. The gas water heater according to any one of claims 1 to 6, characterized in that: The controller is also used to control the gas water heater to exit the waterfall mode when the water flow signal indicates that the water flow is interrupted for a third preset time.

8. The gas water heater according to any one of claims 1 to 6, characterized in that: The gas water heater also includes a fan for blowing air into the heating device; The controller is also used to control the rotation speed of the fan according to the opening of the gas regulating valve, wherein the rotation speed of the fan is positively correlated with the opening of the gas regulating valve.

9. The gas water heater according to any one of claims 1 to 6, characterized in that: The gas water heater further comprises a temperature sensor disposed at the water inlet of the water circuit; The controller is also used to: during the operation of the gas water heater in the waterfall mode, determine whether the water flow at the rated heat load current flow rate can reach a preset temperature after being heated by the heating device; When the rated heat load can make the water flow at the current flow rate reach the preset temperature, controlling the opening of the gas regulating valve and the working power of the booster pump so that the water flow at the current flow rate flows out of the gas water heater at the preset temperature; When the rated heat load cannot make the water flow of the current flow rate reach the preset temperature, the gas regulating valve is controlled to be fully opened and the booster pump is controlled to stop working, so as to control the gas water heater to exit the waterfall mode.

10. The gas water heater according to any one of claims 1 to 6, characterized in that: The controller is also used to control the gas water heater to start a zero cold water mode when a second preset condition is met; The second preset condition includes: the water flow signal indicates that the water flow is interrupted for a second preset number of times and then flows again within a fourth preset time.

11. A method for controlling a gas water heater, characterized in that: The gas water heater comprises: a water path, a water flow detection device arranged on the water path, a heating device for heating the water flow in the water path, a gas regulating valve and a gas pipeline for conveying gas to the heating device, wherein the gas regulating valve and the heating device are sequentially connected in series on the gas pipeline along the gas flow direction; The control method of the gas water heater includes: controlling the booster pump and the gas regulating valve according to the water flow signal from the water flow detection device to control the gas water heater to start the waterfall mode, wherein the booster pump is used to connect the water circuit, and when the gas water heater operates in the waterfall mode, the output water flow of the gas water heater is greater than the rated water flow.

12. The control method of the gas water heater according to claim 11, characterized in that: According to the water flow signal from the water flow detection device, the booster pump and the gas regulating valve are controlled to control the gas water heater to start the waterfall mode, including: When a first preset condition is met, the gas regulating valve and the booster pump are controlled so that the outlet water temperature of the gas water heater is a preset temperature and the output water flow rate is greater than the rated water flow rate, so as to start the waterfall mode; Wherein, the first preset condition includes: the water flow signal indicates that the water flow starts to flow again after being interrupted for a first preset number of times within a first preset time.

13. The control method of the gas water heater according to claim 12, characterized in that: The water flow detection device comprises a flow meter, The first preset condition also includes: before a third moment, the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range for at least a second preset time, wherein the third moment is the starting moment of the first preset time.

14. The control method of the gas water heater according to claim 13, characterized in that: The control method further comprises: Starting from each first moment or second moment, performing a first timing operation to determine whether the water flow signal of the flow meter indicates that the water flows at a flow rate within a preset flow range within at least a second preset time thereafter; Among them, the third flow threshold is within the preset flow range, the first moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from less than the third flow threshold to greater than or equal to the third flow threshold and less than or equal to the upper limit value of the preset flow range, and the second moment is the moment when the water flow signal of the flow meter indicates that the water flow changes from greater than the upper limit value of the preset flow range to less than or equal to the upper limit value and greater than or equal to the lower limit value of the preset flow range.

15. The control method of the gas water heater according to any one of claims 11 to 14, characterized in that: The control method further comprises: When the water flow signal indicates that the water flow is interrupted for a third preset time, the gas water heater is controlled to exit the waterfall mode.

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