CN116242033A - Gas water heater control method, system and gas water heater - Google Patents

Abstract

The invention discloses a control method and a control system of a gas water heater and the gas water heater, wherein the gas water heater comprises a fan motor, a fan impeller and a booster pump impeller coaxial with the fan impeller, the fan motor drives the fan impeller to rotate, and the control method of the gas water heater comprises the following steps: s11, judging whether the actual heat load is smaller than the theoretical heat load, if so, executing the step S12; s12, controlling the fan impeller to be meshed with the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate. According to the invention, the preset hot water meets the user requirement through the theoretical heat load, and the gas water heater is regulated through the actual heat load, so that the problem of unstable combustion of the gas water heater under different gas pressures can be solved, when the gas water heater cannot meet the requirement of heating hot water, the fan impeller drives the booster pump impeller to rotate, and the pressure is increased for the gas, so that the pressure deficiency of the gas is overcome, and the gas water heater can heat the hot water.

Description

Gas water heater control method, system and gas water heater

technical field

The invention relates to the field of gas water heaters, in particular to a gas water heater control method and system and a gas water heater.

Background technique

When using gas water heaters in winter, due to the low temperature of tap water, gas water heaters usually operate under heavy load. During the peak hours of gas consumption, or in some areas where the pressure of the gas pipeline network is low, the pressure of the gas cannot meet the operating requirements of the water heater under heavy load, so that the temperature of the hot water burned is low and cannot meet the user's bathing requirements, bringing users Troubled, greatly reducing the experience of using gas water heaters. In the prior art, it is mainly by adjusting the operating speed of the fan to maintain an appropriate air-fuel ratio, so as to solve the problem of unstable combustion of the water heater under different pressures. However, for the case where the gas pressure is too low, reducing the fan speed still cannot meet the requirements of heating hot water. Therefore, it is necessary to further solve the disadvantage that the gas water heater cannot heat hot water under the condition of low gas pressure.

Contents of the invention

The technical problem to be solved by the present invention is to provide a gas water heater control method and system and a gas water heater to overcome the defect that the gas water heater in the prior art cannot heat hot water when the gas pressure is low.

The present invention solves the above technical problems through the following technical solutions:

According to the first aspect of the present invention, a gas water heater control method is provided, which is applied to a gas water heater. The gas water heater includes a fan motor and a fan impeller, and the fan motor drives the fan impeller to rotate. The gas water heater also includes a The booster pump impeller coaxial with the fan impeller, the gas water heater control method includes the following steps:

S11. Determine whether the actual heat load is less than the theoretical heat load, and if so, perform step S12;

S12. Control the fan impeller to mesh with the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate.

Preferably, after step S12, it also includes:

S13. Judging whether the actual heat load is smaller than the theoretical heat load, if so, execute step S14;

S14. Output prompt information, the prompt information is used to indicate that the gas pressure is low and manual maintenance is required.

Preferably, if the judgment condition in step S11 is yes, then step S111 is first performed, including:

S111. Control the speed of the fan to decrease to a preset threshold;

S112. Determine whether the actual heat load is smaller than the theoretical heat load, if yes, execute step S12.

Preferably, before step S11 includes:

S101. Obtain the inlet water temperature, water flow rate and actual outlet water temperature of the gas water heater;

S102. Calculate and obtain the theoretical heat load according to the inlet water temperature, the water flow rate, and the preset outlet water temperature;

S103. Calculate and obtain the actual heat load according to the inlet water temperature, the water flow rate, and the actual outlet water temperature.

Preferably, if the judgment condition in step S11 is yes, then step S1101 is first performed, including:

S1101. Determine whether the actual heat load is the maximum combustion load, if yes, execute step S111; if not, execute step S1102;

S1102. Increase the actual heat load to the maximum combustion load, and then return to step S11.

Preferably, if the judgment condition in step S11 is yes, then step S110 is first performed, including:

S110. Determine whether the actual outlet water temperature is lower than the preset outlet water temperature, if so, execute step S12; then execute step S13';

S13', judging whether the actual outlet water temperature is lower than the preset outlet water temperature, if so, execute step S14;

S14. Output prompt information, the prompt information is used to indicate that the gas pressure is low and manual maintenance is required.

Preferably, if the judgment condition in step S110 is yes, then step S111 is first performed, including:

S111. Control the speed of the fan to decrease to a preset threshold;

S112'. Determine whether the actual outlet water temperature is lower than the preset outlet water temperature, if yes, execute step S12.

According to the second aspect of the present invention, a gas water heater control system is provided, which is applied to a gas water heater. The gas water heater includes a fan motor and a fan impeller, and the fan motor drives the fan impeller to rotate. The gas water heater also includes a The booster pump impeller coaxial with the fan impeller, the gas water heater system includes a first judging module and an meshing module:

The first judging module is used to judge whether the actual heat load is less than the theoretical heat load, and if so, call the meshing module;

The engagement module is used to control the meshing of the fan impeller and the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate.

Preferably, the gas water heater control system further includes a second judgment module and a prompt module:

The second judging module is used to judge whether the actual heat load is less than the theoretical heat load, and if so, call the prompt module;

The prompting module is used to output prompting information, and the prompting information is used to indicate that the gas pressure is low and manual maintenance is required.

Preferably, the gas water heater control system further includes a speed reduction module and a third judging module:

The first judging module is also used to call the deceleration module when the judging result is yes;

The speed reduction module is used to control the speed of the fan to a preset threshold;

The third judging module is used to judge whether the actual heat load is smaller than the theoretical heat load, and if so, invoke the meshing module.

Preferably, the gas water heater control system further includes an acquisition module, a first calculation module and a second calculation module:

The acquiring module is used to acquire the inlet water temperature, water flow rate and actual outlet water temperature of the gas water heater;

The first calculation module is used to calculate and obtain the theoretical heat load according to the inlet water temperature, the water flow rate and the preset outlet water temperature;

The second calculating module is used to calculate and obtain the actual heat load according to the inlet water temperature, the water flow rate and the actual outlet water temperature.

Preferably, it is characterized in that the gas water heater control system also includes a fourth judgment module and a load regulation module:

The fourth judging module is used to judge whether the actual heat load is the maximum combustion load, if so, call the deceleration module, if not, call the load regulation module;

The load adjustment module is used to increase the actual heat load to the maximum combustion load, and then invoke the first judgment module.

Preferably, the gas water heater control system further includes a fifth judging module, a sixth judging module and a prompt module:

The first judging module is also used to call the fifth judging module when the judging result is yes;

The fifth judging module is used to judge whether the actual outlet water temperature is lower than the preset outlet water temperature, and if so, call the meshing module;

The sixth judging module is used to judge whether the actual outlet water temperature is lower than the preset outlet water temperature, and if so, call the prompt module;

The prompting module is used to output prompting information, and the prompting information is used to indicate that the gas pressure is low and manual maintenance is required.

Preferably, the gas water heater control system further includes a speed reduction module and a seventh judging module:

The fifth judging module is also used to call the deceleration module when the judging result is yes;

The speed reduction module is used to control the speed of the fan to a preset threshold;

The seventh judging module is used to judge whether the actual outlet water temperature is lower than the preset outlet water temperature, and if so, invoke the engagement module.

According to a third aspect of the present invention, a gas water heater is provided, including the gas water heater control system of the present invention.

The positive progress effect of the present invention is:

The invention uses the theoretical heat load to make the predetermined output hot water more in line with the needs of users, and adjusts the gas water heater through the actual heat load, which can solve the problem of unstable combustion of the gas water heater under different gas pressures. Only the fan impeller rotates. When the gas water heater enters the low-pressure mode, it firstly reduces the air volume by reducing the speed of the fan impeller to maintain a suitable air-fuel ratio and improve combustion efficiency. When the demand for heating hot water is still not met, the present invention uses the fan impeller It drives the rotation of the impeller of the booster pump to increase the pressure of the gas to make up for the lack of pressure of the gas itself, so that the gas water heater can heat hot water. At the same time, the present invention can also adjust the gas water heater according to the actual outlet water temperature, which can meet different demands for heating hot water and improve user experience. Through the dual judgment of temperature and load, the gas water heater is prevented from misjudging and entering the logic of low air pressure.

Description of drawings

Fig. 1 is a schematic flowchart of a gas water heater control method according to Embodiment 1 of the present invention.

Fig. 2 is a schematic flowchart of obtaining theoretical heat load and actual heat load in a gas water heater control method according to Embodiment 1 of the present invention.

Fig. 3 is a schematic structural diagram of a gas booster device in a gas water heater control method according to Embodiment 1 of the present invention.

Fig. 4 is a schematic flowchart of a gas water heater control method according to Embodiment 2 of the present invention.

Fig. 5 is a schematic flowchart of a gas water heater control method according to Embodiment 3 of the present invention.

Fig. 6 is a schematic flowchart of a gas water heater control method according to Embodiment 4 of the present invention.

Fig. 7 is a schematic flowchart of a gas water heater control method according to Embodiment 5 of the present invention.

Fig. 8 is a schematic structural diagram of a gas water heater control system according to Embodiment 6 of the present invention.

Fig. 9 is a schematic structural diagram of a gas water heater according to Embodiment 7 of the present invention.

Detailed ways

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples.

Example 1

This embodiment provides a gas water heater control method, referring to Figure 1, the gas water heater control method includes the following steps:

S11. Determine whether the actual heat load is smaller than the theoretical heat load, if yes, execute step S12; if not, the water heater operates in the current state, and outputs hot water stably.

Among them, the thermal load is used to characterize the ability of the water heater to heat hot water. As an optional implementation, the thermal load can be calculated by using the formula of water flow and temperature. Assuming that the thermal load is P, the formula for calculating the thermal load is: P=kqΔT, where k is a constant, q is the water flow, and ΔT is the absolute value of the temperature difference of the water. For example, a 16L water heater can increase the temperature of 16L of water by 25 degrees per minute, so its heat load can be 16 × 25 = 400, the greater the heat load, the faster the water heater heats hot water, and the greater the gas pressure. In this embodiment, before judging whether the actual heat load is less than the theoretical heat load, it is necessary to obtain the theoretical heat load and the actual heat load of the water heater. Specifically, as shown in FIG. 2 , the following steps are included:

S101. Obtain the inlet water temperature, water flow rate and actual outlet water temperature of the gas water heater.

Wherein, the water outlet temperature is collected by setting a temperature sensor in the water outlet pipe, and a temperature sensor and a water flow sensor are respectively arranged in the water inlet pipe to collect the water inlet temperature and the water flow rate. As an optional implementation, the data of inlet water temperature, outlet water temperature and inlet water flow can be obtained by actively accessing the temperature sensor and water flow sensor, or the temperature sensor and flow sensor can actively upload the inlet water temperature and outlet water temperature. and water flow data.

S102. Calculate and obtain a theoretical heat load according to the inlet water temperature, the water flow rate, and the preset outlet water temperature.

Wherein, the preset outlet water temperature can be the theoretical temperature in the water heater program, or the temperature set by the user through the control panel of the water heater, usually a range value, for example, the set temperature is between [40, 50]. Substituting the inlet water temperature, water flow rate and preset outlet water temperature into the heat load calculation formula, the theoretical heat load P _theory =kq(T _theory -T ₀ ), where k is a constant, q is the water inlet flow, and T _Theory is the theoretical outlet water temperature, and T ₀ is the inlet water temperature.

As an optional implementation, when the cold water enters the gas water heater from the water inlet pipe, the water heater runs to the theoretical heat load by controlling the gas proportional valve and the fan speed, so that the hot water output from the water outlet pipe is more in line with the user's needs.

S103. Calculate and obtain an actual heat load according to the inlet water temperature, the water flow rate, and the actual outlet water temperature.

When the hot water flows out from the outlet pipe, substituting the inlet water temperature, water flow rate and actual outlet water temperature into the calculation formula of the heat load, the actual heat load _Pactual =kq( _Tactual -T ₀ ), where k is a constant , q is the water inlet flow, _Tactual is the actual outlet water temperature, and T ₀ is the inlet water temperature.

Under the normal working condition of the water heater, the smaller the water flow rate, the faster the hot water temperature rises. In practical applications, the actual heat load of the water heater is compared with the minimum threshold of the theoretical heat load. If the water flow decreases, the theoretical heat load used for comparison value rises. As an optional implementation, assuming that the rated water flow of the water heater is 8L and the set temperature is between [40, 50], when the water flow of the water inlet pipe is 8L, the actual heat load should not be lower than the preset The theoretical heat load corresponding to the temperature of 40°, when the water flow rate of the water inlet pipe is 6L, the actual heat load should not be lower than the theoretical heat load corresponding to the preset temperature of 42°, of course, this embodiment is not limited to the above numerical range , you can set the judgment rules according to the actual situation.

According to the above judgment rules, when the actual heat load is lower than the theoretical heat load, it means that the water heater cannot meet the water demand. It is judged that the gas pressure of the water heater is insufficient, and the gas water heater enters the low pressure working state; when the actual heat load is within the range of the theoretical heat load, the water heater operates according to the current state and outputs hot water stably.

S12. Control the meshing of the impeller of the fan and the impeller of the booster pump so that the impeller of the fan drives the impeller of the booster pump to rotate.

When the gas pressure is insufficient, the gas pressure can be increased through the gas booster device. The structure of the gas booster device is shown in Figure 3. The fan impeller 1 and the booster pump impeller 2 are arranged on the same rotating shaft 4, and the fan impeller 1 and The booster pump impeller 2 is meshed, so that the fan impeller 1 drives the booster pump impeller 2 to rotate. When the booster pump impeller 2 rotates, it can increase the pressure of the gas to make up for the lack of gas pressure.

A clutch 3 is also arranged on the rotating shaft 4. As an optional embodiment, the working mode of the clutch 3 is energized combination. In this embodiment, the clutch 3 includes a first runner 5, a second runner 6, a coil 7 and spring 8, wherein the first runner 5 is a moving iron core runner coaxially connected with the booster pump impeller 2, and the second runner 6 is a moving iron core runner coaxially connected with the fan impeller 1. The coil 7 is arranged on the iron core of the first runner 5, and the coil 7 and the iron core form an electromagnet, which can make the first runner 5 generate magnetism by controlling the current to the coil 7, thereby attracting and engaging with the second runner 6 . The spring 8 is arranged between the first rotating wheel 5 and the second rotating wheel 6 . As an optional embodiment, one end of the spring 8 is fixedly connected to the contact part of the first rotating wheel 5 . Of course, this embodiment is not limited to the above-mentioned clutch.

When the water heater enters the state of low air pressure, after the control clutch 3 is energized, the coil 7 is energized to make the iron core of the first runner 5 generate electromagnetic force, and the first runner 5 overcomes the elastic force of the spring 7 and moves toward the second runner 6. The runner 5 and the second runner 6 are attracted and meshed through the gears. At this time, the rotating shaft 4 is engaged, and the fan impeller 1 and the booster pump impeller 2 are connected through the rotating shaft 4. When the fan impeller 1 rotates, the rotating shaft 4 drives The impeller 2 of the booster pump rotates, so that the fan motor can simultaneously drive the impeller 1 of the fan and the impeller 2 of the booster pump to rotate, thereby increasing the gas pressure.

S13. Determine whether the actual heat load is smaller than the theoretical heat load, if yes, execute step S14; if not, the water heater operates according to the current state, and outputs hot water stably.

It should be noted that the judgment logic of S4 in this embodiment is consistent with that of S2, except that the working state of the water heater is different. At this time, the working state of the gas water heater is a low pressure state. After the gas pressure is increased by the gas booster pump, the actual heat When the load rises, compare the actual heat load with the theoretical heat load again. When the actual heat load is lower than the theoretical heat load, it indicates that the water heater still cannot meet the water demand, and a prompt message is output. The prompt message is used to indicate that the gas pressure is too low; When the heat load is within the range of the theoretical heat load, the water heater operates according to the current state and outputs hot water stably.

S14. Output prompt information, the prompt information is used to indicate that the gas pressure is low and manual maintenance is required.

As an optional implementation, a display board is provided on the gas water heater, and a prompt message of low gas pressure is output through the display board, so as to notify manual maintenance of the gas pipeline or the gas water heater.

This embodiment uses the theoretical heat load to make the scheduled output of hot water more in line with user needs, and adjusts the gas water heater through the actual heat load, which can solve the problem of unstable combustion of the gas water heater under different gas pressures. The gas water heater is in normal mode. Only the impeller of the fan rotates. When the gas water heater enters the low pressure mode, the impeller of the booster pump is driven by the fan impeller to increase the pressure of the gas to make up for the lack of pressure of the gas itself, so that the gas water heater can heat hot water.

Example 2

As shown in Figure 4, the gas water heater control method of this embodiment is a further improvement on Embodiment 1, and the water heater first enters a transition state before entering a low pressure state. When the judgment condition in step S11 is yes, step S111 is executed first. More specifically, the following steps are included:

S111. Control the speed of the fan to decrease to a preset threshold.

By reducing the running speed of the fan motor, the speed of the fan impeller is reduced, reducing the heat taken away by the fan, and making the actual heat load of the water heater gradually approach the theoretical heat load. Since the gas water heater is combusted according to a certain proportion of gas mixed with a certain proportion of air, as an optional implementation, the preset threshold is 80% of the maximum speed of the fan impeller, that is, the speed of the fan impeller can be reduced to at most the original speed. 80%. When the gas is insufficient, control the speed of the fan impeller to reduce the air volume, thereby reducing the proportion of air, and adjust to an appropriate air-fuel ratio as much as possible to meet the combustion requirements, thereby increasing the actual heat load.

S112 . Determine whether the actual heat load is smaller than the theoretical heat load. If yes, perform step S12 ; if not, the water heater operates according to the current state, and outputs hot water stably.

At this time, the working state of the gas water heater is in a transitional state. By controlling the speed of the fan impeller to drop, the actual heat load increases, and then compares the actual heat load with the theoretical heat load. When the actual heat load is lower than the theoretical heat load, the representative water heater still cannot meet the requirements. Water demand, it is judged that the gas pressure is insufficient, and the gas water heater enters the low pressure working state; when the actual heat load is within the range of the theoretical heat load, the water heater operates according to the current state, and outputs hot water stably.

In this embodiment, when the actual heat load is lower than the theoretical heat load, it enters the transition state first, which further prevents the gas water heater from entering the low pressure state by mistake. By reducing the speed of the fan impeller, reduce the heat taken away by the fan, and adjust the appropriate air-fuel ratio to improve the combustion efficiency; if the demand for heating water cannot be met after the reduction, it will enter a low pressure state. In addition, since the operating speed of the fan decreases, noise is reduced and user experience is improved.

Example 3

As shown in Figure 5, this embodiment is a further improvement on Embodiment 2. Before the water heater enters the transition state, it is judged whether the gas water heater is operating with maximum load combustion. Specifically, it includes the following steps:

S1101. Determine whether the actual heat load is the maximum combustion load, if yes, execute step S111; if not, execute step S1102.

Among them, the maximum combustion load is used to represent the heat load calculated by the gas water heater under the maximum gas pressure, and to monitor whether the current water heater is operating at the maximum combustion load. If the current gas water heater is already operating at the maximum combustion load, it means that the gas Insufficient pressure, the gas water heater enters a transitional state. If it is detected that the gas water heater is not operating at the maximum combustion load, increase the current actual heat load to the maximum combustion load.

S1102. Increase the actual heat load to the maximum combustion load, and then return to step S11.

If the gas water heater is not running at the maximum combustion load, as an optional implementation, by adjusting the gas proportional valve to the maximum, the water heater can reach the current maximum combustion load. After increasing the actual heat load of the water heater to the maximum combustion load, compare the actual heat load and the theoretical heat load of the water heater again.

In this embodiment, before the gas water heater enters the transition state, it is further judged whether the gas is running at the maximum combustion load. According to the actual demand, when the actual heat load is lower than the theoretical heat load and the water heater is not running at the maximum The current maximum combustion load runs to meet the heating water demand, and at the same time prevents the gas water heater from accidentally entering into an abnormal working state.

Example 4

This implementation provides another gas water heater control method, as shown in Figure 6, the gas water heater control method includes the following steps:

S11. Determine whether the actual heat load is smaller than the theoretical heat load, if yes, perform step S110; if not, the water heater operates according to the current state, and outputs hot water stably.

Among them, the thermal load is used to characterize the ability of the water heater to heat hot water. As an optional implementation, the thermal load can be calculated by using the formula of water flow and temperature. Assuming that the thermal load is P, the formula for calculating the thermal load is: P=kqΔT, where k is a constant, q is the water flow, and ΔT is the absolute value of the temperature difference of the water. For example, a 16L water heater can increase the temperature of 16L of water by 25 degrees per minute, so its heat load can be 16 × 25 = 400, the greater the heat load, the faster the water heater heats hot water, and the greater the gas pressure. In this embodiment, before judging whether the actual heat load is less than the theoretical heat load, it is necessary to obtain the theoretical heat load and the actual heat load of the water heater. Specifically, as shown in FIG. 2 , the following steps are included:

S101. Obtain the inlet water temperature, water flow rate and actual outlet water temperature of the gas water heater.

Wherein, the water outlet temperature is collected by setting a temperature sensor in the water outlet pipe, and a temperature sensor and a water flow sensor are respectively arranged in the water inlet pipe to collect the water inlet temperature and the water flow rate. As an optional implementation, the data of inlet water temperature, outlet water temperature and inlet water flow can be obtained by actively accessing the temperature sensor and water flow sensor, or the temperature sensor and flow sensor can actively upload the inlet water temperature and outlet water temperature. and water flow data.

S102. Calculate and obtain a theoretical heat load according to the inlet water temperature, the water flow rate, and the preset outlet water temperature.

Wherein, the preset outlet water temperature can be the theoretical temperature in the water heater program, or the temperature set by the user through the control panel of the water heater, usually a range value, for example, the set temperature is between [40, 50]. Substituting the inlet water temperature, water flow rate and preset outlet water temperature into the heat load calculation formula, the theoretical heat load P _theory =kq(T _theory -T ₀ ), where k is a constant, q is the water inlet flow, and T _Theory is the theoretical outlet water temperature, and T ₀ is the inlet water temperature.

As an optional implementation, when the cold water enters the gas water heater from the water inlet pipe, the water heater runs to the theoretical heat load by controlling the gas proportional valve and the fan speed, so that the hot water output from the water outlet pipe is more in line with the user's needs.

S103. Calculate and obtain an actual heat load according to the inlet water temperature, the water flow rate, and the actual outlet water temperature.

When the hot water flows out from the outlet pipe, substituting the inlet water temperature, water flow rate and actual outlet water temperature into the calculation formula of the heat load, the actual heat load _Pactual =kq( _Tactual -T ₀ ), where k is a constant , q is the water inlet flow, _Tactual is the actual outlet water temperature, and T ₀ is the inlet water temperature.

Under the normal working condition of the water heater, the smaller the water flow rate, the faster the hot water temperature rises. In practical applications, the actual heat load of the water heater is compared with the minimum threshold of the theoretical heat load. If the water flow decreases, the theoretical heat load used for comparison value rises. As an optional implementation, assuming that the rated water flow of the water heater is 8L and the set temperature is between [40, 50], when the water flow of the water inlet pipe is 8L, the actual heat load should not be lower than the preset The theoretical heat load corresponding to the temperature of 40°, when the water flow rate of the water inlet pipe is 6L, the actual heat load should not be lower than the theoretical heat load corresponding to the preset temperature of 42°, of course, this embodiment is not limited to the above numerical range , you can set the judgment rules according to the actual situation.

According to the above judgment rules, when the actual heat load is lower than the theoretical heat load, it indicates that the gas cannot meet the load operation requirements of the water heater. According to the selected implementation mode, it can be further judged whether the actual outlet water temperature can meet the hot water demand of the user. When the actual heat load is within the range of the theoretical heat load, the water heater operates according to the current state and outputs hot water stably.

S110. Determine whether the actual outlet water temperature is lower than the preset outlet water temperature, if yes, perform step S1101; if not, the water heater operates according to the current state, and outputs hot water stably.

At this time, the working state of the water heater is the normal working state. Compare the actual outlet water temperature with the preset minimum threshold of outlet water temperature. When the actual outlet water temperature is lower than the preset minimum outlet water temperature threshold, it indicates that the actual outlet water temperature cannot meet the water demand. In one embodiment selected, it is further judged whether the gas water heater is operating with maximum load combustion. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

S1101. Determine whether the actual heat load is the maximum combustion load, if yes, execute step S111; if not, execute step S1102.

Among them, the maximum combustion load is used to represent the heat load calculated by the gas water heater under the maximum gas pressure, and to monitor whether the current water heater is operating at the maximum combustion load. If the current gas water heater is already operating at the maximum combustion load, it means that the gas If the pressure is insufficient, the gas water heater enters a transitional state, and the operating speed of the fan motor is controlled to decrease, so that the speed of the fan impeller can be reduced to a preset threshold. If it is detected that the gas water heater is not operating at the maximum combustion load, increase the current actual heat load to the maximum combustion load.

S1102. Increase the actual heat load to the maximum combustion load, and then return to step S11.

If the gas water heater is not running at the maximum combustion load, as an optional implementation, by adjusting the gas proportional valve to the maximum, the water heater can reach the current maximum combustion load. After increasing the actual heat load of the water heater to the maximum combustion load, compare the actual heat load and the theoretical heat load of the water heater again.

S111. Control the speed of the fan to decrease to a preset threshold.

If the current gas water heater is already running at the maximum combustion load, and the hot water temperature cannot meet the user's needs, it will enter a transitional state. By reducing the running speed of the fan motor, the speed of the fan impeller is reduced, reducing the heat taken away by the fan, and making the actual heat load of the water heater gradually approach the theoretical heat load. Since the gas water heater is combusted according to a certain proportion of gas mixed with a certain proportion of air, as an optional implementation, the preset threshold is 80% of the maximum speed of the fan impeller, that is, the speed of the fan impeller can be reduced to at most the original speed. 80%. When the gas is insufficient, control the speed of the fan impeller to reduce the air volume, thereby reducing the proportion of air, and adjust to an appropriate air-fuel ratio as much as possible to meet the combustion requirements, thereby increasing the actual heat load.

S112', judging whether the actual outlet water temperature is lower than the preset outlet water temperature, if yes, execute step S12; if not, the water heater operates according to the current state, and outputs hot water stably.

At this time, the working state of the gas water heater is a transitional state. By controlling the speed of the fan impeller to drop, the actual outlet water temperature rises. Compare the actual outlet water temperature with the minimum threshold of the preset outlet water temperature. When the actual outlet water temperature is lower than the preset minimum outlet water temperature When the threshold is reached, it indicates that the water heater still cannot meet the water demand, and the gas water heater enters a low pressure working state. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

S12. Control the fan impeller to mesh with the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate.

When the gas pressure is insufficient, the gas pressure can be increased through the gas booster device. The structure of the gas booster device is shown in Figure 3. The fan impeller 1 and the booster pump impeller 2 are arranged on the same rotating shaft 4, and the fan impeller 1 and The booster pump impeller 2 is meshed, so that the fan impeller 1 drives the booster pump impeller 2 to rotate. When the booster pump impeller 2 rotates, it can increase the pressure of the gas to make up for the lack of gas pressure.

A clutch 3 is also arranged on the rotating shaft 4. As an optional embodiment, the working mode of the clutch 3 is energized combination. In this embodiment, the clutch 3 includes a first runner 5, a second runner 6, a coil 7 and spring 8, wherein the first runner 5 is a moving iron core runner coaxially connected with the booster pump impeller 2, and the second runner 6 is a moving iron core runner coaxially connected with the fan impeller 1. The coil 7 is arranged on the iron core of the first runner 5, and the coil 7 and the iron core form an electromagnet, which can make the first runner 5 generate magnetism by controlling the current to the coil 7, thereby attracting and engaging with the second runner 6 . The spring 8 is arranged between the first rotating wheel 5 and the second rotating wheel 6 . As an optional embodiment, one end of the spring 8 is fixedly connected to the contact part of the first rotating wheel 5 . Of course, this embodiment is not limited to the above-mentioned clutch.

In the normal state of the water heater, the fan motor only drives the fan impeller 1 to rotate, so that an appropriate amount of air can be mixed into the gas. When the water heater enters the state of low air pressure, after the control clutch 3 is energized, the coil 7 is energized to make the iron core of the first runner 5 generate electromagnetic force, and the first runner 5 overcomes the elastic force of the spring 7 and moves toward the second runner 6. The runner 5 and the second runner 6 are attracted and meshed through the gears. At this time, the rotating shaft 4 is engaged, and the fan impeller 1 and the booster pump impeller 2 are connected through the rotating shaft 4. When the fan impeller 1 rotates, the rotating shaft 4 drives The impeller 2 of the booster pump rotates, so that the fan motor can simultaneously drive the impeller 1 of the fan and the impeller 2 of the booster pump to rotate, thereby increasing the gas pressure.

S13', judging whether the actual outlet water temperature is lower than the preset outlet water temperature, if yes, execute step S14; if not, the water heater operates according to the current state, and outputs hot water stably.

At this time, the working state of the gas water heater is a low pressure state. After increasing the gas pressure through the gas booster pump, the actual outlet water temperature rises. Compare the actual outlet water temperature with the minimum threshold of the preset outlet water temperature. When the temperature reaches the lowest threshold, a prompt message is output, and the prompt message is used to indicate that the gas pressure is too low. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

S14. Output prompt information, the prompt information is used to indicate that the gas pressure is low and manual maintenance is required.

As an optional implementation, a display board is provided on the gas water heater, and a prompt message of low gas pressure is output through the display board, so as to notify manual maintenance of the gas pipeline or the gas water heater.

In this embodiment, under the judgment condition of heat load, the judgment condition of temperature is added, and the double judgment of temperature and heat load is used to further prevent the water heater from entering the abnormal working state by mistake. When using a gas water heater, due to the low temperature of tap water, the gas water heater usually operates under heavy load, and the outlet water temperature can directly reflect whether the hot water meets the user's water demand, which improves the user experience.

Example 5

As shown in FIG. 7 , the gas water heater control method of this embodiment is a further optimization of the above method. When the judgment condition in step S11 is yes, the process starting from step 110 and the process starting from step 1101 can be executed simultaneously. It should be noted that, in this embodiment, the judgment logic of step 1101' is consistent with the judgment logic of step 1101, so in actual use, it is only necessary to make a judgment once, and in the subsequent process, the water heater feeds back the heat load at the same time and water temperature, and control the water heater to enter different working states. The specific implementation methods are consistent with the above-mentioned schemes, and will not be repeated here.

Example 6

This embodiment provides a gas water heater control system, as shown in Figure 8, the gas water heater control system includes an acquisition module 21, a first judgment module 22, an engagement module 23, a second judgment module 24, a prompt module 25, and a speed reduction module 26. The third judgment module 27 , the first calculation module 28 , the second calculation module 29 , the fourth judgment module 210 , the fifth judgment module 211 , the sixth judgment module 212 , the seventh judgment module 213 and the load adjustment module 214 .

It should be noted that the judgment logic in the first judging module 22, the second judging module 24 and the third judging module 27 are the same, but the working status of the gas water heater is different, and they are actually the same module. For the convenience of description, here Distinguish between first, second and third. Similarly, the fifth judging module 211 , the sixth judging module 212 and the seventh judging module 213 are actually the same module.

The acquiring module 21 is used to acquire the inlet water temperature, water flow rate and actual outlet water temperature of the gas water heater. Wherein, the water outlet temperature is collected by setting a temperature sensor in the water outlet pipe, and a temperature sensor and a water flow sensor are respectively arranged in the water inlet pipe to collect the water inlet temperature and the water flow rate. As an optional implementation, the acquisition module 21 can acquire the data of the inlet water temperature, outlet water temperature and inlet water flow by actively accessing the temperature sensor and the water flow sensor, or the temperature sensor and the flow sensor can actively upload the inlet water temperature. , Outlet water temperature and inflow flow data to.

The first calculating module 28 is used to calculate the theoretical heat load according to the inlet water temperature, the water flow rate and the preset outlet water temperature. Wherein, the preset outlet water temperature can be the theoretical temperature in the water heater program, or the temperature set by the user through the control panel of the water heater, usually a range value, for example, the set temperature is between [40, 50]. The first calculation module 28 substitutes the inlet water temperature, the water flow rate and the preset outlet water temperature into the calculation formula of the heat load, and can obtain the theoretical heat load P _theory =kq(T _theory -T ₀ ), where k is a constant, and q is Inlet water flow, T _theory is the theoretical outlet water temperature, and T ₀ is the inlet water temperature.

As an optional implementation, when the cold water enters the gas water heater from the water inlet pipe, the water heater runs to the theoretical heat load by controlling the gas proportional valve and the fan speed, so that the hot water output from the water outlet pipe is more in line with the user's needs.

The second calculation module 29 is used to calculate the actual heat load according to the inlet water temperature, the water flow rate and the actual outlet water temperature. When hot water flows out from the outlet pipe, the second calculation module 29 substitutes the inlet water temperature, water flow rate and actual outlet water temperature into the calculation formula of heat load, and the actual heat load _Pactual =kq( _Tactual -T ₀ ), Among them, k is a constant, q is the water inlet flow rate, _Tactual is the actual outlet water temperature, and T ₀ is the inlet water temperature.

The first judging module 22 is used to judge whether the actual heat load is less than the theoretical heat load in the normal working state of the water heater. If so, call the fourth judging module 210; Under the normal working condition of the water heater, the smaller the water flow rate, the faster the hot water temperature rises. In practical applications, the actual heat load of the water heater is compared with the minimum threshold of the theoretical heat load. If the water flow decreases, the theoretical heat load used for comparison value rises. As an optional implementation, assuming that the rated water flow of the water heater is 8L and the set temperature is between [40, 50], when the water flow of the water inlet pipe is 8L, the actual heat load should not be lower than the preset The theoretical heat load corresponding to the temperature of 40°, when the water flow rate of the water inlet pipe is 6L, the actual heat load should not be lower than the theoretical heat load corresponding to the preset temperature of 42°, of course, this embodiment is not limited to the above numerical range , the first judging module 22 can set judging rules according to the actual situation.

The fourth judging module 210 is used to judge whether the actual heat load is the maximum combustion load. If so, the gas water heater enters a transitional state, and the speed reduction module 26 is invoked; Among them, the maximum combustion load is used to characterize the heat load calculated by the gas water heater under the maximum gas pressure. The fourth judgment module 210 monitors whether the current water heater is running at the maximum combustion load. If the current gas water heater is already running at the maximum combustion load , it means that the gas pressure is insufficient, and the gas water heater enters a transitional state.

The load adjustment module 214 is used to increase the actual heat load to the maximum combustion load. If the gas water heater is not operating at the maximum combustion load, as an optional implementation, the water heater can reach the current maximum by adjusting the gas proportional valve to the maximum. combustion load. After the actual heat load of the water heater is increased to the maximum combustion load, the first judging module 22 is invoked. And in the normal working state, the first judging module 22 compares the actual heat load and the theoretical heat load of the water heater again.

The speed reduction module 26 is used to control the speed of the fan to decrease to a preset threshold. The speed reduction module 26 reduces the speed of the fan impeller by reducing the running speed of the fan motor, reducing the heat taken away by the fan, so that the actual heat load of the water heater gradually approaches the theoretical heat load. Since the gas water heater is combusted according to a certain proportion of gas mixed with a certain proportion of air, as an optional implementation, the preset threshold is 80% of the maximum speed of the fan impeller, that is, the speed of the fan impeller can be reduced to at most the original speed. 80%. When the gas is insufficient, the speed reduction module 26 controls the speed of the fan impeller to decrease to reduce the air volume, thereby reducing the proportion of air, and adjusting to an appropriate air-fuel ratio as much as possible to meet the combustion requirements, thereby increasing the actual heat load.

The third judging module 27 is used for judging whether the actual heat load is less than the theoretical heat load in the transitional state of the water heater. If yes, the engagement module 23 is invoked; At this time, the working state of the gas water heater is a transition state. The speed reduction module 26 controls the speed of the fan impeller to drop, and the actual heat load rises. The third judging module 27 compares the actual heat load with the theoretical heat load again. When the actual heat load is lower than the theoretical heat load When the heat load is on, if the water heater still cannot meet the water demand, it is judged that the gas pressure is insufficient, and the gas water heater enters the low pressure working state; when the actual heat load is within the range of the theoretical heat load, the water heater operates according to the current state and outputs hot water stably .

The engagement module 23 is used to control the meshing between the impeller of the fan and the impeller of the booster pump so that the impeller of the fan drives the impeller of the booster pump to rotate. When the gas pressure is insufficient, the gas pressure can be increased through the gas booster device. The structure of the gas booster device is shown in FIG. The impeller 1 meshes with the booster pump impeller 2, so that the fan impeller 1 drives the booster pump impeller 2 to rotate. When the booster pump impeller 2 rotates, it can increase the pressure of the gas to make up for the lack of gas pressure.

A clutch 3 is also arranged on the rotating shaft 4. As an optional embodiment, the working mode of the clutch 3 is energized combination. In this embodiment, the clutch 3 includes a first runner 5, a second runner 6, a coil 7 and spring 8, wherein the first runner 5 is a moving iron core runner coaxially connected with the booster pump impeller 2, and the second runner 6 is a moving iron core runner coaxially connected with the fan impeller 1. The coil 7 is arranged on the iron core part of the first runner 5, and the coil 7 and the iron core part form an electromagnet, and the engagement module 23 can make the first runner 5 generate magnetism by controlling the current to the coil 7, so as to be compatible with the second runner 5. 6 Attractive engagement. The spring 8 is arranged between the first rotating wheel 5 and the second rotating wheel 6 . As an optional embodiment, one end of the spring 8 is fixedly connected to the contact part of the first rotating wheel 5 . Of course, this embodiment is not limited to the above-mentioned clutch.

When the water heater enters the low air pressure state, after the engagement module 23 controls the clutch 3 to be energized, the coil 7 is energized to make the iron core of the first runner 5 generate electromagnetic force, and the first runner 5 overcomes the elastic force of the spring 7 and moves toward the second runner 6 , the first runner 5 and the second runner 6 are attracted and meshed through the gears. At this time, the rotating shaft 4 is engaged, and the fan impeller 1 and the booster pump impeller 2 are connected through the rotating shaft 4. When the fan impeller 1 rotates, it rotates The shaft 4 drives the impeller 2 of the booster pump to rotate, so that the fan motor can simultaneously drive the impeller 1 of the fan and the impeller 2 of the booster pump to rotate, thereby increasing the gas pressure.

The second judging module 24 is used to judge whether the actual heat load is less than the theoretical heat load when the water heater is in a low pressure state. If so, call the prompt module 25; At this time, the working state of the gas water heater is a low pressure state. After the engagement module 23 increases the gas pressure through the gas booster pump, the actual heat load rises. The second judging module 24 compares the actual heat load with the theoretical heat load again. When the actual heat load is low When the theoretical heat load indicates that the water heater still cannot meet the water demand, a prompt message will be output, which is used to indicate that the gas pressure is too low; when the actual heat load is within the range of the theoretical heat load, the water heater will run according to the current state and output stably hot water.

The prompt module 25 is used to output prompt information, which is used to indicate that the gas pressure is low and manual maintenance is required. As an optional implementation, a display board is provided on the gas water heater, and a prompt message of low gas pressure is output through the display board, so as to notify manual maintenance of the gas pipeline or the gas water heater.

As another optional implementation manner, the first judging module 22 is further configured to call the fifth judging module 211 when the judging condition is yes.

The fifth judging module 211 is used to judge whether the actual outlet water temperature is lower than the preset outlet water temperature under the normal state of the water heater, and if so, call the fourth judging module 210; if not, the water heater operates according to the current state and outputs hot water stably. At this time, the working state of the water heater is the normal working state. The fifth judging module 211 compares the actual outlet water temperature with the preset minimum threshold of the outlet water temperature. When the actual outlet water temperature is lower than the preset minimum outlet water temperature threshold, an optional In an embodiment, it is further judged whether the gas water heater is operating with maximum load combustion. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

The sixth judging module 212 is used for judging whether the actual outlet water temperature is lower than the preset outlet water temperature in the transitional state of the water heater, and if so, calls the engagement module 23; At this time, the working state of the gas water heater is a transition state. The speed reduction module 26 controls the speed of the fan impeller to decrease, and the actual outlet water temperature rises. When the temperature is lower than the minimum threshold of the preset outlet water temperature, the gas water heater enters the low pressure working state. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

The seventh judging module 213 is used to judge whether the actual outlet water temperature is lower than the preset outlet water temperature when the water heater is in a low pressure state, and if so, call the prompt module 25; At this time, the working state of the gas water heater is a low pressure state. After the engagement module 23 increases the gas pressure through the gas booster pump, the actual outlet water temperature rises. The seventh judging module 213 compares the actual outlet water temperature with the preset minimum threshold of the outlet water temperature again. When the actual outlet water temperature is lower than the preset minimum threshold of the outlet water temperature, the prompt module 25 outputs prompt information, and the prompt information is used to indicate that the gas pressure is too low. When the actual outlet water temperature is within the range of the preset outlet water temperature, the water heater will run according to the current state and output hot water stably.

Example 7

This embodiment provides a gas water heater, including the gas water heater control system of Embodiment 6. As shown in FIG. Proportional valve 35, outlet water temperature sensor 36, fan 37, gas booster pump 38, burner 39 and heat exchanger 310.

Specifically, the main controller 31 is electrically connected to the wind pressure sensor 32, the water flow sensor 22, the water inlet temperature sensor 34, the gas proportional valve 35, the water outlet temperature sensor 36, the fan 37 and the gas booster pump 310; the water inlet temperature sensor 34 The water flow sensor 33 is arranged on the water inlet pipe of the gas water heater, and the outlet water temperature sensor 36 is arranged on the water outlet pipe of the gas water heater. Under normal conditions, when using a gas water heater, cold water flows in from the water inlet pipe, the water flow sensor 33 detects the water flow rate and sends it to the main controller 31, the water inlet temperature sensor 34 detects the water inlet temperature and sends it to the main controller 31, The main controller 31 calculates the theoretical heat load of the water heater according to the water inlet flow rate, the water inlet temperature, and the user-preset water outlet temperature, and determines the initial speed of the fan according to the theoretical heat load to start the fan 37 and open the gas proportional valve 35 at the same time. Fan 37 and gas proportional valve 35 respectively send air and gas into burner 39 for combustion, the heat generated by burner 39 is transferred to heat exchanger 310, cold water becomes hot water after passing through heat exchanger 310, and hot water flows from the outlet pipe Outflow, the outlet water temperature sensor 36 detects the actual outlet water temperature and sends it to the main controller 31.

The main controller 31 calculates the actual heat load of the water heater according to the water inlet flow rate, the water inlet temperature and the actual water outlet temperature, and compares the actual heat load with the theoretical heat load. As another optional embodiment, the main controller 31 compares the actual water outlet temperature and preset the minimum threshold of outlet water temperature. When the actual heat load or the actual outlet water temperature meets the hot water demand, the hot water will be output stably. If the demand for hot water is not met, if the main controller 31 detects that the gas water heater is not burning at the maximum combustion load, the main controller 31 controls the gas proportional valve 35 to increase the gas supply, thereby increasing the combustion load of the gas water heater. During the process of controlling the gas proportional valve, the main controller 31 continues to judge whether the actual heat load reaches the theoretical heat load or whether the actual outlet water temperature reaches the minimum threshold of the preset outlet water temperature. When the conditions are met, the water heater outputs hot water stably; The water heater operates at the maximum combustion load, that is, the gas proportional valve 35 is adjusted to the maximum opening, but still cannot meet the hot water demand, then it is judged that the pressure of the gas pipe is insufficient, and the main controller 31 controls the fan 37 to reduce the operating speed, thereby reducing the air volume.

The main controller 31 continues to judge whether the actual heat load reaches the theoretical heat load or whether the actual outlet water temperature reaches the minimum threshold of the preset outlet water temperature. When the condition is met, the water heater outputs hot water stably. If the hot water demand cannot be met after the speed of the fan 37 drops, the main controller 31 starts the gas booster pump 38 to increase the pressure of the gas to make up for the lack of gas pressure.

If the gas booster pump 38 increases the gas pressure, if still unable to meet the hot water demand, the display panel will output a low gas pressure prompt message, thereby notifying manual maintenance of gas pipelines or gas water heaters, etc. troubled.

In this implementation, the gas water heater feeds back heat load or temperature multiple times, and implements different processing schemes under different feedbacks, avoiding unnecessary energy consumption and improving user experience. Judging whether the gas supply pressure is sufficient by the heat load and temperature of the water heater, quantifying the conditions for judging low air pressure, improving the accuracy of the program operation, preventing the gas water heater from entering the low air pressure state by mistake, and reducing the air volume in the low air pressure state, improving the gas consumption. Power, increase the combustion heat load under low pressure, effectively improve the user's bathing comfort under low pressure.

Although the specific implementation of the present invention has been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (15)

1. The control method of the gas water heater is applied to the gas water heater, the gas water heater comprises a fan motor and a fan impeller, the fan motor drives the fan impeller to rotate, and the control method of the gas water heater is characterized by further comprising a booster pump impeller coaxial with the fan impeller, and comprises the following steps of:

s11, judging whether the actual heat load is smaller than the theoretical heat load, if so, executing the step S12;

s12, controlling the fan impeller to be meshed with the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate.

2. The gas water heater control method according to claim 1, further comprising, after step S12:

s13, judging whether the actual heat load is smaller than the theoretical heat load, if so, executing the step S14;

s14, outputting prompt information, wherein the prompt information is used for representing that the gas pressure is low and manual overhaul is needed.

3. The gas water heater control method according to claim 1, wherein if the determination condition in step S11 is yes, step S111 is performed first, including:

s111, controlling the rotating speed of the fan to be reduced to a preset threshold value;

And S112, judging whether the actual heat load is smaller than the theoretical heat load, if so, executing the step S12.

4. The gas water heater control method according to claim 1, characterized by comprising, before step S11:

s101, acquiring the water inlet temperature, water flow and actual water outlet temperature of the gas water heater;

s102, calculating to obtain the theoretical heat load according to the water inlet temperature, the water flow and a preset water outlet temperature;

s103, calculating to obtain the actual heat load according to the water inlet temperature, the water flow and the actual water outlet temperature.

5. The gas water heater control method according to claim 3, wherein if the determination condition in step S11 is yes, step S1101 is executed first, comprising:

s1101, judging whether the actual heat load is the maximum combustion load, if so, executing step S111; if not, executing step S1102;

s1102, the actual heat load is increased to the maximum combustion load, and then the process returns to step S11.

6. The gas water heater control method according to claim 1, wherein if the determination condition in step S11 is yes, step S110 is performed first, comprising:

S110, judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, if so, executing the step S12; then step S13' is performed;

s13', judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, if so, executing the step S14;

s14, outputting prompt information, wherein the prompt information is used for representing that the gas pressure is low and manual overhaul is needed.

7. The gas water heater control method according to claim 6, wherein if the determination condition in step S110 is yes, step S111 is performed first, comprising:

s111, controlling the rotating speed of the fan to be reduced to a preset threshold value;

s112', judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, if so, executing the step S12.

8. The utility model provides a gas heater control system, is applied to gas heater, gas heater includes fan motor and fan impeller, fan motor drive fan impeller rotates, its characterized in that, gas heater still include with the coaxial booster pump impeller of fan impeller, gas heater system includes first judgement module and meshing module:

the first judging module is used for judging whether the actual heat load is smaller than the theoretical heat load or not, and if yes, the meshing module is called;

The meshing module is used for controlling the fan impeller to mesh with the booster pump impeller so that the fan impeller drives the booster pump impeller to rotate.

9. The gas water heater control system of claim 8, further comprising a second determination module and a prompt module:

the second judging module is used for judging whether the actual heat load is smaller than the theoretical heat load or not, and if yes, a prompting module is called;

the prompt module is used for outputting prompt information, and the prompt information is used for representing that the gas pressure is low and manual overhaul is needed.

10. The gas water heater control system of claim 8, further comprising a speed reduction module and a third determination module:

the first judging module is also used for calling the speed reducing module when the judging result is yes;

the speed reducing module is used for controlling the rotating speed of the fan to reach a preset threshold value;

and the third judging module is used for judging whether the actual heat load is smaller than the theoretical heat load or not, and if yes, the meshing module is called.

11. The gas water heater control system of claim 8, further comprising an acquisition module, a first calculation module, and a second calculation module:

The acquisition module is used for acquiring the water inlet temperature, the water flow and the actual water outlet temperature of the gas water heater;

the first calculation module is used for calculating the theoretical heat load according to the water inlet temperature, the water flow and the preset water outlet temperature;

the second calculation module is used for calculating the actual heat load according to the water inlet temperature, the water flow and the actual water outlet temperature.

12. The gas water heater control system of claim 10, further comprising a fourth determination module and a load adjustment module:

the fourth judging module is used for judging whether the actual heat load is the maximum combustion load, if yes, the speed reducing module is called, and if not, the load adjusting module is called;

the load adjustment module is used for increasing the actual heat load to the maximum combustion load and then calling the first judgment module.

13. The gas water heater control system of claim 8, further comprising a fifth determination module, a sixth determination module, and a prompt module:

the first judging module is further used for calling the fifth judging module when the judging result is yes;

The fifth judging module is used for judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, and if yes, the meshing module is called;

the sixth judging module is used for judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, and if yes, the prompting module is called;

the prompt module is used for outputting prompt information, and the prompt information is used for representing that the gas pressure is low and manual overhaul is needed.

14. The gas water heater control system of claim 13, further comprising a speed reduction module and a seventh determination module:

the fifth judging module is further used for calling the speed reducing module when the judging result is yes;

the speed reducing module is used for controlling the rotating speed of the fan to reach a preset threshold value;

and the seventh judging module is used for judging whether the actual water outlet temperature is smaller than the preset water outlet temperature, and if yes, calling the meshing module.

15. A gas water heater comprising a gas water heater control system as claimed in any one of claims 7 to 14.

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