A control method for a gas water heater

Abstract

The present invention discloses a control method for a gas water heater. After a user turns on a massage bath function, since the water flow may fluctuate or errors may occur in the adjustment process during the operation of the gas water heater, the heating coefficient value in each stage of the water pressure fluctuation cycle is continuously corrected to ensure that the subsequent demand load value adjustment work becomes more and more accurate. The method is simple and reliable and can ensure that the temperature of the gas water heater remains constant when the water pressure changes, thereby achieving a massage bath effect.

Description

Technical Field

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

[0002] Existing gas water heaters are all constant-temperature models. After the user turns on the water, the system quickly locks in the user's target temperature and water pressure through calculations, maintaining a constant water temperature and thus meeting normal bathing needs. However, most gas water heaters in the related art generally cannot maintain a constant water outlet temperature when the water pressure changes, making it difficult for gas water heaters to meet user comfort requirements. Summary of the Invention

[0003] The present invention aims to solve, at least to a certain extent, one of the problems existing in the existing related technologies. To this end, the present invention proposes a control method for a gas water heater. The method is simple and reliable and can keep the outlet water temperature constant when the water pressure of the gas water heater changes, thereby achieving a massage bath effect.

[0004] The above purpose is achieved through the following technical solutions:

[0005] A control method for a gas water heater, the control method comprising:

[0006] The gas water heater controls the opening steps of the water regulating valve according to a first preset step number;

[0007] Obtain the current water flow value and inlet water temperature value, and calculate the required load value based on the obtained data through a calculation formula;

[0008] Determining the number of fire rows required for ignition of the gas water heater according to the calculated demand load value, and performing ignition and combustion according to the determined number of fire rows;

[0009] After a first preset interval, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result;

[0010] After the outlet water temperature reaches a constant state, the opening of the water regulating valve is increased according to a second preset number of steps to enter a decreasing phase of the water pressure fluctuation cycle;

[0011] After the first preset time, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state;

[0012] After the second preset time, the opening of the water regulating valve is reduced according to a third preset number of steps to enter the rising phase of the water pressure fluctuation cycle;

[0013] After the third preset time, the high-pressure stabilization phase of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state;

[0014] After the fourth preset time, the water pressure fluctuation cycle returns to the descending stage, and the cycle is repeated to keep the outlet water temperature constant.

[0015] In some embodiments, the calculation formula of the demand load value is as follows: P0=L0*(Tpreset-Tinfluent) / K0, wherein P0 is the current demand load value, L0 is the current water flow value at the first preset step number, Tpreset is the preset temperature value, Tinfluent is the inlet water temperature value, and K0 is the heating coefficient.

[0016] In some embodiments, after the first preset interval, the step of comparing the outlet water temperature value with a preset temperature value and adjusting the demand load value according to the comparison result includes:

[0017] After a first preset interval, determining whether the outlet water temperature is greater than a preset temperature value;

[0018] If so, reducing the demand load value;

[0019] If not, the demand load value is increased.

[0020] In some embodiments, the step of waiting until the outlet water temperature reaches a constant state further includes:

[0021] Until the outlet water temperature reaches a constant state;

[0022] Record the current actual output load value and the upper limit of the water pressure before the outlet water temperature reaches a constant state;

[0023] The upper limit value of the constant temperature heating coefficient is calculated by the following calculation formula: Kmax0=Pmax0 / L1*(Tpreset-Tinwater), where Kmax0 is the upper limit value of the constant temperature heating coefficient, Pmax0 is the upper limit value of the constant temperature output load, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value.

[0024] In some embodiments, the step of increasing the opening of the water regulating valve by a second preset number of steps to enter the descending phase of the water pressure fluctuation cycle further includes:

[0025] The lower limit of the output load in the descending stage is calculated by the following calculation formula: Pmin1=Lmin1*(Tpreset-Tinwater) / Kmin1, wherein Pmin1 is the lower limit of the output load in the descending stage, Lmin1 is the lower limit of the water flow in the descending stage, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, Kmin1 is the lower limit of the heating coefficient in the descending stage, and the lower limit of the heating coefficient in the descending stage of the first water pressure fluctuation cycle is equal to the upper limit of the constant temperature heating coefficient;

[0026] After the second preset interval, the required load value is lowered according to the difference between the constant temperature output load upper limit and the output load lower limit in the descending stage, and so on, until the low-voltage stable stage is entered after the first preset time.

[0027] In some embodiments, after the first preset time period, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state, the step includes:

[0028] After entering the low-pressure stable stage, determine whether the outlet water temperature is greater than a preset temperature value; if so, reduce the required load value; if not, increase the required load value;

[0029] Until the outlet water temperature reaches a constant state, the lower limit of the output load in the low-pressure stable stage is recorded.

[0030] In some embodiments, the step of recording the lower limit of the output load in the low-voltage stable stage further includes:

[0031] After recording the output load lower limit value during the low voltage stabilization stage;

[0032] The lower limit of the heating coefficient in the low-pressure stable stage is calculated by the following calculation formula: Kmin2 = Pmin2 / L1*(Tpreset-Tinwater), where Kmin2 is the lower limit of the output load in the low-pressure stable stage, Pmin2 is the lower limit of the output load in the low-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value;

[0033] The lower limit value of the heating coefficient in the descending phase of the next water pressure fluctuation cycle is replaced by the lower limit value of the heating coefficient in the low pressure stable phase.

[0034] In some embodiments, after the second preset time period, the step of reducing the opening number of the water regulating valve according to a third preset number of steps to enter the rising phase of the water pressure fluctuation cycle includes:

[0035] The output load upper limit during the rising phase is calculated using the following formula: Pmax3 = Lmax3 * (Tpreset - Tinwater) / Kmax3, where Pmax3 is the output load upper limit during the rising phase, Lmax3 is the water flow upper limit during the rising phase, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax3 is the heating coefficient upper limit during the rising phase.

[0036] After the third preset interval time, the required load value is increased according to the difference between the output load upper limit value in the rising stage and the output load lower limit value in the low-pressure stable stage, and so on, until the high-pressure stable stage is entered after the third preset time.

[0037] In some embodiments, after the third preset time period, the high-pressure stabilization phase of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state, the step includes:

[0038] After entering the high-pressure stable stage, determine whether the outlet water temperature is greater than a preset temperature value; if so, reduce the required load value; if not, increase the required load value;

[0039] Until the outlet water temperature reaches a constant state, the output load upper limit value in the high pressure stabilization stage is recorded.

[0040] In some embodiments, the step after recording the output load upper limit value in the high-voltage stable stage further includes:

[0041] After recording the output load upper limit value during the high voltage stabilization stage;

[0042] The upper limit of the heating coefficient in the high-pressure stable stage is calculated by the following calculation formula: Kmax4 = Pmax4 / L1*(Tpreset-Tinwater), where Kmax4 is the upper limit of the output load in the high-pressure stable stage, Pmax4 is the upper limit of the output load in the high-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value;

[0043] The upper limit value of the heating coefficient in the rising phase of the next water pressure fluctuation cycle is replaced by the upper limit value of the output load in the high pressure stable phase.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects:

[0045] 1. The control method of the gas water heater of the present invention is simple and reliable, and can keep the outlet water temperature constant when the water pressure of the gas water heater changes, thereby achieving a massage bath effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 1 is a flow chart of a gas water heater control method according to an embodiment of the present invention;

[0047] Figure 2 1 is a load curve diagram of the gas water heater in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of the technical solutions claimed by the present invention.

[0049] Example:

[0050] like Figure 1 and 2 As shown, this embodiment provides a control method for a gas water heater. After the user turns on the massage bath function, since the water flow may fluctuate or there may be some errors in the adjustment process during the operation of the gas water heater, the heating coefficient value in each stage of the water pressure fluctuation cycle is continuously corrected to ensure that the subsequent demand load value adjustment work is more and more accurate. The method is simple and reliable, and can ensure that the temperature of the gas water heater remains constant when the water pressure changes, thereby achieving a massage bath effect.

[0051] Existing gas water heaters come in different power ratings, each with its own specific tiering scheme. For example, a 2-4-6 tiered gas water heater can utilize two, four, or six fires for heating, depending on the power selected by the user. When the gas water heater leaves the factory, the maximum wattage of the two-firer tier must be greater than the minimum wattage of the four-firer tier, and the maximum wattage of the four-firer tier must be greater than the minimum wattage of the six-firer tier. This ensures continuity when switching between wattages.

[0052] like Figure 2As shown, the minimum power (2PL) for two rows of fires is 3 kW, the maximum power (2PH) for two rows of fires is 7 kW, and the minimum power (4PL) for four rows of fires is 6 kW, ensuring that the maximum power of two rows of fires is greater than the minimum power of four rows of fires. The maximum power (4PH) for four rows of fires is 13 kW, the minimum power (6PL) for six rows of fires is 10 kW, and the maximum power (6PH) for six rows of fires is 23 kW, ensuring that the maximum power of four rows of fires is greater than the minimum power of six rows of fires, thus ensuring continuity when switching power in the gas water heater.

[0053] Through calculation, it is found that 1KW can heat water to 14 degrees when the water flow rate is 1L / min. That is, the combustion power P = water flow rate L×(water temperature Tpreset-water temperature Tinwater) / 14. When the user takes a bath, the combustion power P generally does not change according to the water flow rate and preset temperature set by the user. At the same time, due to the existence of the deviation coefficient Kmax, the combustion power Pmax0 can be calculated according to Pmax0=Lmax0×(water temperature Tpreset-water temperature Tinwater) / 14, and then through Figure 2 The power curve chart for a gas water heater shown in the figure estimates the proportional valve opening (i.e., the current flowing through the proportional valve) and the corresponding gear position. For example, if the required power is calculated to be 12 kW, either 4 or 6 fires can be used to meet the demand. However, due to significant water pressure fluctuations and the water pressure being at its lowest at this time, 6 fires should be selected for control. This is because the upper limit of 4 fires is 13 kW, meaning there is only a 1 kW difference between 4 and 6 fires, while the lower limit of 6 fires is 10 kW, meaning there is a 2 kW difference between 6 and 4 fires. This means that using 4 fires is more likely than using 6 fires to cause the gas water heater to automatically select a different gear position due to water pressure fluctuations, causing the gas water heater to automatically select a different gear position.

[0054] In this embodiment, the gas water heater can pre-set the maximum load that the entire machine can heat. For example, when the rated heat load is set to Pmax=23kW, the gas water heater is equivalent to 13L / min*25 degrees. 1kW means that when the water flow rate is 1L / min, the maximum heating is 14 degrees, that is, the heating coefficient k=14. The calculation formula is P(kw)=L*(Tpreset-Tinlet) / 14). At normal pressure, k=14. When the primary gas pressure is too high, this value is greater than 14, otherwise it is less than 14.

[0055] The water regulating valve adjusts the opening steps of the water channel by adjusting the number of steps of its opening through a stepper motor. The adjustment action includes forward and reverse rotation. Forward rotation means increasing the opening of the water valve, and reverse rotation means decreasing the opening of the water valve. When the water heater is at the rated heat load and the outlet water temperature is lower than the user's required temperature, the water valve opening can be adjusted to a smaller degree so that the outlet water temperature reaches the user's required temperature.

[0056] Since when the step number of the water regulating valve is at the maximum opening, the water regulating valve is at 0 steps, the controller MCU can detect the reset signal, reverse once, the step number is plus 1, and forward once, the step number is minus 1. The time for adjusting 1 step is 4ms, and 1300 steps takes a total of 5s.

[0057] In this embodiment, the user turns on the massage bath function through the operation panel or APP control. The user can set the water pressure fluctuation period Y through the mobile phone APP. The water pressure fluctuation period Y is divided into four stages: descending stage, descending stable stage, rising stage, and rising stable stage. The time of each stage is the same. In addition, the water pressure fluctuation amplitude X, that is, X=Lmin / Lmax, where the upper limit value of the water flow rate in the water pressure fluctuation period is set to Lmax, and the lower limit value of the water flow rate in the water pressure fluctuation period is Lmin=Lmax*X. In this embodiment, the water pressure fluctuation period Y is preferably set to 30S to 60S, and the water pressure fluctuation amplitude X is preferably set to 50%-100%.

[0058] like Figure 1 As shown, the steps of the gas water heater control method in this embodiment specifically include the following steps:

[0059] In step S101, the gas water heater controls the opening steps of the water regulating valve according to a first preset step number.

[0060] Step S102: obtaining the current water flow rate value and the inlet water temperature value, and performing calculations based on the obtained data using a calculation formula to obtain a required load value.

[0061] Specifically, the calculation formula for the demand load value is as follows: P0 = L0*(Tpreset-Tinfluent) / K0, where P0 is the current demand load value, L0 is the current water flow value at the first preset step, Tpreset is the preset temperature value, Tinfluent is the inlet water temperature value, and K0 is the heating coefficient.

[0062] In this embodiment, after the user turns on the massage bath function, the water regulating valve controls the opening steps of the water regulating valve according to the first preset step number. In this embodiment, the first preset step number is preferably 500 steps, but is not limited to the above value. Other more appropriate values ​​can also be selected according to actual needs, so that the gas water heater is heated according to the water pressure value at the highest point of the water pressure fluctuation cycle, and then the current water flow value L0 and the inlet water temperature value Tinwater are collected, and the heating coefficient is preferably set to 14, and the required load value is calculated by the calculation formula.

[0063] Step S103 , determining the number of fire rows required for ignition of the gas water heater according to the calculated demand load value, and performing ignition and combustion according to the determined number of fire rows.

[0064] In this embodiment, by Figure 2The proportional valve current value and the selected gear are calculated by using the medium load curve. For example, if the required load is 12 kW, either 4 or 6 rows of fire can be used to meet the combustion requirements. However, since the water pressure needs to fluctuate downward, at this point the maximum load is reached, so 4 rows of fire should be selected for control. As the water pressure increases, the water temperature remains constant, thus preventing the gas water heater from switching gears.

[0065] Step S104: After a first preset interval, the outlet water temperature value is compared with a preset temperature value, and the required load value is adjusted according to the comparison result.

[0066] Specifically, after the first preset interval, the outlet water temperature value is compared with the preset temperature value, and the step of adjusting the required load value according to the comparison result includes:

[0067] After the first preset interval time, determine whether the outlet water temperature is greater than the preset temperature value;

[0068] If so, reduce the demand load value;

[0069] If not, increase the demand load value.

[0070] In this embodiment, after calculating the required load value using a calculation formula, the first preset interval is burned according to the calculated required load value. The outlet water temperature is then compared with the preset temperature value, and the required load value is fine-tuned based on the comparison result. If the outlet water temperature is greater than the preset temperature value, the required load value is reduced, i.e., the current value of the gas water heater proportional valve is reduced or the gear position is switched from high to low. If the outlet water temperature is less than or equal to the preset temperature value, the required load value is increased, i.e., the current value of the gas water heater proportional valve is increased or the gear position is switched from low to high. In this embodiment, the first preset interval is preferably set to 10 seconds or 15 seconds, but is not limited to these time values. Other more appropriate time values ​​can also be selected based on actual needs.

[0071] Step S105: After the outlet water temperature reaches a constant state, the opening of the water regulating valve is increased according to a second preset number of steps to enter the descending phase of the water pressure fluctuation cycle.

[0072] Specifically, the steps until the outlet water temperature reaches a constant state further include:

[0073] Until the outlet water temperature reaches a constant state;

[0074] Record the current actual output load value and the upper limit of water pressure before the outlet water temperature reaches a constant state;

[0075] The upper limit value of the constant temperature heating coefficient is calculated by the following calculation formula: Kmax0 = Pmax0 / L1*(Tpreset-Tinwater), where Kmax0 is the upper limit value of the constant temperature heating coefficient, Pmax0 is the upper limit value of the constant temperature output load, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value.

[0076] In this embodiment, after the outlet water temperature reaches a constant state, the fine-tuning control of the demand load value is stopped, and the upper limit of the heating coefficient after the water pressure fluctuation is stabilized is recorded, that is, the upper limit of the constant temperature heating coefficient Pmax0 is obtained. Since Pmax0 = L1*(Tpreset-Tinwater) / Kmax0, where Pmax0 is the upper limit of the constant temperature output load, L1 is the current actual water flow value, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax0 is the upper limit of the constant temperature heating coefficient. The upper limit of the constant temperature heating coefficient is calculated by reverse deduction through the above calculation formula. The upper limit of the constant temperature heating coefficient is calculated by the following calculation formula: Kmax0 = Pmax0 / L1*(Tpreset-Tinwater), where Kmax0 is the upper limit of the constant temperature heating coefficient, Pmax0 is the upper limit of the constant temperature output load, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value.

[0077] Furthermore, the step of increasing the opening of the water regulating valve by a second preset number of steps to enter the descending phase of the water pressure fluctuation cycle also includes:

[0078] The lower limit of the output load in the descending stage is calculated by the following formula: Pmin1 = Lmin1 * (Tpreset - Tinwater) / Kmin1, where Pmin1 is the lower limit of the output load in the descending stage, Lmin1 is the lower limit of the water flow in the descending stage, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, Kmin1 is the lower limit of the heating coefficient in the descending stage, and the lower limit of the heating coefficient in the descending stage of the first water pressure fluctuation cycle is equal to the upper limit of the constant temperature heating coefficient;

[0079] After the second preset interval, the demand load value is lowered according to the difference between the upper limit of the constant temperature output load and the lower limit of the output load in the descending stage, and so on, until the low-voltage stable stage is entered after the first preset time.

[0080] In this embodiment, when the opening steps of the water regulating valve are between 500 and 1300 steps, the opening steps of the water regulating valve are proportional to the water flow rate. Specifically, L1 = (L0-L0 / 2.6)*(1300-Bmin) / (1300-500)+L0 / 2.6, where L1 is the current actual water flow rate value, L0 is the actual water flow rate value corresponding to the first preset step number, 2.6 is the threshold, 1300 is the preset opening steps of the water regulating valve, Bmin is the current actual opening steps of the water regulating valve, and 500 is the first preset step number. More preferably, L0 is equivalent to Lmax, L1 = Lmin = X*Lmax, and then L0 and L1 are substituted into this calculation formula to obtain the current opening steps Bmin of the water regulating valve. In addition, in the descending stage, when the opening steps of the water regulating valve are increased for the first time, the number of opening steps required to be increased each time is (B-500) / (Y / 4), where B is the opening steps of the water regulating valve when the water pressure fluctuates to the lower limit of the water flow in the descending stage, 500 is the first preset step, and Y / 4 is the duration of each stage in the water pressure fluctuation cycle. When the opening steps of the water regulating valve are continued to be increased, the recorded opening steps of the water regulating valve Bmin are used for calculation, thereby completing the opening step control of the water regulating valve.

[0081] In this embodiment, the lower limit value of the output load in the descending stage is first calculated by the following calculation formula. When the demand load value is adjusted for the first time, the lower limit value of the heating coefficient in the descending stage Kmin1 can preferably be calculated using the upper limit value of the constant temperature heating coefficient, so that the lower limit value of the heating coefficient in the descending stage of the first water pressure fluctuation cycle is equal to the upper limit value of the constant temperature heating coefficient. The demand load value is slowly reduced, and it is reduced once every 1s. The demand load value required to be reduced each time is (Pmax0-Pmin1) / (Y / 4), where Pmax0 is the upper limit value of the constant temperature output load, Pmin1 is the lower limit value of the output load in the descending stage, and Y / 4 is the duration of each stage in the water pressure fluctuation cycle. When the number of steps of the opening of the water regulating valve is continued to be adjusted later, the recorded lower limit value of the heating coefficient in the descending stage Kmin1 is used for calculation, thereby completing the regulation and control of the demand load of the gas water heater.

[0082] Step S106: After the first preset time, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state.

[0083] Specifically, after the first preset time, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state. The steps include:

[0084] After entering the low-pressure stable stage, determine whether the outlet water temperature is greater than the preset temperature value; if so, reduce the demand load value; if not, increase the demand load value;

[0085] Until the outlet water temperature reaches a constant state, record the lower limit of the output load in the low-pressure stable stage.

[0086] In this embodiment, after the low pressure stabilizes, it is maintained for a period of time, and then the constant temperature control scheme output fine-tuning control is performed. Specifically, when the outlet water temperature is greater than the target temperature, the demand load value is reduced, and vice versa. When the outlet water temperature reaches a constant state, the demand load lower limit Pmin2 of the low pressure stabilization phase output is recorded. Pmin2 = L1 * (Tpreset - Tinwater) / Kmin2, where Pmin2 is the low pressure stabilization phase output load lower limit, L1 is the current actual water flow rate, Tpreset is the preset temperature value, Tinwater is the inlet water temperature, and Kmin2 is the low pressure stabilization phase output load lower limit. By reverse deduction through the above calculation formula, the lower limit value of the output load in the low-pressure stable stage is calculated, and the upper limit value of the constant temperature heating coefficient is calculated by the following calculation formula: Kmin2 = Pmin2 / L1*(Tpreset-Tinwater), wherein Kmin2 is the lower limit value of the output load in the low-pressure stable stage, Pmin2 is the lower limit value of the output load in the low-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and the lower limit value of the heating coefficient in the descending stage of the next water pressure fluctuation cycle is replaced by the lower limit value of the heating coefficient in the low-pressure stable stage in the current water pressure fluctuation cycle, and then the calculation is continued to complete the regulation and control of the demand load of the gas water heater.

[0087] In this embodiment, after entering the low-pressure stable stage, the current water flow value Lmin2 is compared with X*Lmax, and the demand load value is fine-tuned according to the comparison result. If the current water flow value Lmin2 is greater than X*Lmax, the step number is increased to reduce the water flow and finally recorded. Otherwise, the step number is reduced to increase the water flow.

[0088] Furthermore, the steps after recording the output load lower limit value in the low voltage stable stage also include:

[0089] After recording the output load lower limit value during the low voltage stabilization stage;

[0090] The lower limit of the heating coefficient in the low-pressure stable stage is calculated using the following formula: Kmin2 = Pmin2 / L1*(Tpreset-Tinwater), where Kmin2 is the lower limit of the output load in the low-pressure stable stage, Pmin2 is the lower limit of the output load in the low-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value;

[0091] The lower limit value of the heating coefficient in the descending phase of the next water pressure fluctuation cycle is replaced by the lower limit value of the heating coefficient in the low pressure stable phase.

[0092] Step S107: After the second preset time, the opening number of the water regulating valve is reduced according to the third preset number of steps to enter the rising phase of the water pressure fluctuation cycle.

[0093] Specifically, after the second preset time, the step of reducing the opening number of the water regulating valve according to the third preset number of steps to enter the rising phase of the water pressure fluctuation cycle includes:

[0094] The output load upper limit during the rising phase is calculated using the following formula: Pmax3 = Lmax3 * (Tpreset - Tinwater) / Kmax3, where Pmax3 is the output load upper limit during the rising phase, Lmax3 is the water flow upper limit during the rising phase, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax3 is the heating coefficient upper limit during the rising phase.

[0095] After the third preset interval time, the required load value is increased according to the difference between the output load upper limit value in the rising stage and the output load lower limit value in the low-pressure stable stage, and so on, until the high-pressure stable stage is entered after the third preset time.

[0096] In this embodiment, in the rising stage, the number of opening steps required to be increased each time is (Bmin-500) / (Y / 4), where Bmin is the opening step number of the water regulating valve when the water pressure fluctuates to the lower limit of the water flow in the descending stable stage, 500 is the first preset step number, and Y / 4 is the duration of each stage in the water pressure fluctuation cycle. When the opening step number of the water regulating valve continues to be increased, the recorded water regulating valve opening step number Bmin is used for calculation to complete the opening step number control of the water regulating valve. If the opening step number of the water regulating valve reaches 500 steps, the water flow upper limit value Lmax3 of the rising stage is recorded, and the water regulating valve opening step number of the descending stage of the next water pressure fluctuation cycle is replaced by the water flow upper limit value Lmax3 of the rising stage in the current water pressure fluctuation cycle.

[0097] In this embodiment, since the water flow rate value is proportional to the demand load value, the demand load value will increase accordingly as the water flow rate increases. First, the upper limit of the output load in the rising stage is calculated by the calculation formula. Specifically, Pmax3=Lmax3*(Tpreset-Tinwater) / Kmax3, where Pmax3 is the upper limit of the output load in the rising stage, Lmax3 is the upper limit of the water flow in the rising stage, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax3 is the upper limit of the heating coefficient in the rising stage. Then, the demand load value is adjusted once after every third preset interval time. The demand load value required to be increased each time is (Pmax3-Pmin2) / (Y / 4), where Pmax3 is the upper limit of the output load in the rising stage, Pmin2 is the lower limit of the output load in the low-pressure stable stage, and Y / 4 is the duration of each stage in the water pressure fluctuation cycle, thereby completing the regulation and control of the demand load of the gas water heater.

[0098] Step S108: After the third preset time, the high pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state.

[0099] Specifically, after the third preset time, the high-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state. The steps include:

[0100] After entering the high-pressure stable stage, determine whether the outlet water temperature is greater than the preset temperature value; if so, reduce the demand load value; if not, increase the demand load value;

[0101] Until the outlet water temperature reaches a constant state, record the output load upper limit value in the high-pressure stable stage.

[0102] Furthermore, the steps after recording the output load upper limit value in the high-voltage stable stage also include:

[0103] After recording the output load upper limit value during the high voltage stabilization stage;

[0104] The upper limit of the heating coefficient in the high-pressure stable stage is calculated using the following formula: Kmax4 = Pmax4 / L1 * (Tpreset - Tinwater), where Kmax4 is the upper limit of the output load in the high-pressure stable stage, Pmax4 is the upper limit of the output load in the high-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value;

[0105] The upper limit value of the heating coefficient in the rising phase of the next water pressure fluctuation cycle is replaced by the upper limit value of the output load in the high pressure stable phase.

[0106] In this embodiment, the water pressure is kept stable for a period of time after the rising stage, and fine-tuning control of the constant temperature control is performed. Specifically, when the outlet water temperature value is greater than the preset temperature value, the demand load value is reduced, otherwise the demand load value is increased until the outlet water temperature value reaches a constant state. The output load upper limit Pmax4 of the high-pressure stable stage after the water pressure stabilizes is recorded. Since Pmax4 = L1*(Tpreset-Tinwater) / Kmax4, Pmax4 is the output load upper limit value of the high-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax4 is the output load upper limit value of the high-pressure stable stage. The above calculation formula is used for reverse deduction to calculate the upper limit of the output load in the high-pressure stable stage. The upper limit of the output load in the high-pressure stable stage is calculated by the following calculation formula: Kmax4 = Pmax4 / L1*(Tpreset-Tinwater), where Kmax4 is the upper limit of the output load in the high-pressure stable stage, Pmax4 is the upper limit of the output load in the high-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and the upper limit of the heating coefficient Kmax3 in the rising stage of the next water pressure fluctuation cycle is replaced with the upper limit of the output load in the high-pressure stable stage, and Kmax4 continues to calculate to complete the regulation and control of the demand load of the gas water heater.

[0107] Step S109: After the fourth preset time period, the process returns to the decreasing phase of the water pressure fluctuation cycle, and the cycle continues in this way to keep the outlet water temperature constant.

[0108] In this embodiment, after the fourth preset time period, the water pressure fluctuation cycle returns to the descending stage and continues to the next water pressure fluctuation cycle, thereby ensuring that the subsequent demand load value adjustment work becomes more and more accurate by continuously correcting the heating coefficient value in each stage of the water pressure fluctuation cycle. When the water flow of the gas water heater changes, it can be automatically adjusted adaptively, so that no large deviation will occur, so that when the water pressure of the gas water heater changes, the water outlet temperature can remain constant, thereby achieving a massage bath effect.

[0109] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for controlling a gas water heater, characterized in that: The control method includes: The gas water heater controls the opening steps of the water regulating valve according to the first preset steps; Obtain the current water flow value and inlet water temperature value, and calculate the required load value based on the obtained data through a calculation formula; Determining the number of fire rows required for ignition of the gas water heater according to the calculated demand load value, and performing ignition and combustion according to the determined number of fire rows; After the first preset interval, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result. The demand load value is calculated as follows: P0=L0*(Tpreset-Tinwater) / K0, where P0 is the current demand load value, L0 is the current water flow value at the first preset number of steps, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and K0 is the heating coefficient; After the outlet water temperature reaches a constant state, the opening of the water regulating valve is increased according to a second preset number of steps to enter a decreasing phase of the water pressure fluctuation cycle; After the first preset time, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state; After the second preset time, the opening of the water regulating valve is reduced according to a third preset number of steps to enter the rising phase of the water pressure fluctuation cycle; After the third preset time, the high-pressure stabilization phase of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state; After the fourth preset time, the water pressure fluctuation cycle returns to the descending stage, and the cycle is repeated to keep the outlet water temperature constant.

2. A gas water heater control method according to claim 1, characterized in that: After the first preset interval, the step of comparing the outlet water temperature value with the preset temperature value and adjusting the demand load value according to the comparison result includes: After a first preset interval, determining whether the outlet water temperature is greater than a preset temperature value; If so, reducing the demand load value; If not, the demand load value is increased.

3. The control method of a gas water heater according to claim 1, characterized in that: The step of waiting until the outlet water temperature reaches a constant state further includes: Until the outlet water temperature reaches a constant state; Record the current actual output load value and the upper limit of the water pressure before the outlet water temperature reaches a constant state; The upper limit value of the constant temperature heating coefficient is calculated by the following calculation formula: Kmax0=Pmax0 / L1*(Tpreset-Tinwater), where Kmax0 is the upper limit value of the constant temperature heating coefficient, Pmax0 is the upper limit value of the constant temperature output load, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value.

4. A gas water heater control method according to claim 3, characterized in that: The step of increasing the opening number of the water regulating valve according to the second preset number of steps to enter the descending phase of the water pressure fluctuation cycle further includes: The lower limit of the output load in the descending stage is calculated by the following formula: Pmin1=Lmin1*(Tpreset-Tinwater) / Kmin1, where Pmin1 is the lower limit of the output load in the descending stage, Lmin1 is the lower limit of the water flow in the descending stage, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, Kmin1 is the lower limit of the heating coefficient in the descending stage, and the lower limit of the heating coefficient in the descending stage of the first water pressure fluctuation cycle is equal to the upper limit of the constant temperature heating coefficient; After the second preset interval, the required load value is lowered according to the difference between the constant temperature output load upper limit and the output load lower limit in the descending stage, and so on, until the low-voltage stable stage is entered after the first preset time.

5. A gas water heater control method according to claim 4, characterized in that: After the first preset time, the low-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state. The steps include: After entering the low-pressure stable stage, determine whether the outlet water temperature is greater than a preset temperature value; if so, reduce the required load value; if not, increase the required load value; Until the outlet water temperature reaches a constant state, the lower limit of the output load in the low-pressure stable stage is recorded.

6. A gas water heater control method according to claim 5, characterized in that: The step after recording the lower limit of the output load in the low-voltage stable stage further includes: After recording the output load lower limit value during the low voltage stabilization stage; The lower limit of the heating coefficient in the low-pressure stable stage is calculated by the following calculation formula: Kmin2=Pmin2 / L1*(Tpreset-Tinwater), where Kmin2 is the lower limit of the output load in the low-pressure stable stage, Pmin2 is the lower limit of the output load in the low-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value; The lower limit value of the heating coefficient in the descending phase of the next water pressure fluctuation cycle is replaced by the lower limit value of the heating coefficient in the low pressure stable phase.

7. The control method of a gas water heater according to claim 5, characterized in that: After the second preset time, the step of reducing the opening number of the water regulating valve according to the third preset number of steps to enter the rising phase of the water pressure fluctuation cycle includes: The output load upper limit during the rising phase is calculated using the following formula: Pmax3 = Lmax3 * (Tpreset - Tinwater) / Kmax3, where Pmax3 is the output load upper limit during the rising phase, Lmax3 is the water flow upper limit during the rising phase, Tpreset is the preset temperature value, Tinwater is the inlet water temperature value, and Kmax3 is the heating coefficient upper limit during the rising phase. After the third preset interval time, the required load value is increased according to the difference between the output load upper limit value in the rising stage and the output load lower limit value in the low-pressure stable stage, and so on, until the high-pressure stable stage is entered after the third preset time.

8. A gas water heater control method according to claim 7, characterized in that: After the third preset time, the high-pressure stable stage of the water pressure fluctuation cycle is entered, the outlet water temperature value is compared with the preset temperature value, and the demand load value is adjusted according to the comparison result until the outlet water temperature value reaches a constant state. The steps include: After entering the high-pressure stable stage, determine whether the outlet water temperature is greater than a preset temperature value; if so, reduce the required load value; if not, increase the required load value; Until the outlet water temperature reaches a constant state, the output load upper limit value in the high pressure stabilization stage is recorded.

9. A gas water heater control method according to claim 8, characterized in that: The step after recording the output load upper limit value in the high-voltage stable stage further includes: After recording the output load upper limit value during the high voltage stabilization stage; The upper limit of the heating coefficient in the high-pressure stable stage is calculated by the following calculation formula: Kmax4=Pmax4 / L1*(Tpreset-Tinwater), where Kmax4 is the upper limit of the output load in the high-pressure stable stage, Pmax4 is the upper limit of the output load in the high-pressure stable stage, L1 is the current actual water flow value, Tpreset is the preset temperature value, and Tinwater is the inlet water temperature value; The upper limit value of the heating coefficient in the rising phase of the next water pressure fluctuation cycle is replaced by the upper limit value of the output load in the high pressure stable phase.

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