JPH1114145A - Hot-water supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the temperature of the repeated supply of hot-water from a hot-water supply provided with a bypass. SOLUTION: A data storage part 23 is stored with control mode switching time that is the reference of the ending up time for supplying reboiled water. A mode switching combustion control part 20 controls the hot-water supplying combustion by the feed forward control based on the feed forward heat quantity set up by a feed forward heat quantity setting means 16 from the start of the repeated hot-water supply to the time, before the control mode switching time and after passing the control mode switching time, the hot-water supply combustion is controlled based on the total of the feed forward heat quantity and a feed back heat quantity set up by a feed back heat quantity setting means 17. After the start of the repeated supply of the hot-water being affected by after reboiling, a flow quantity rate control part 22 controls the mixing ratio of the hot-water from the hot-water heat exchanger and the hot-water from the bypass path for maintaining the temperature of the supplying hot-water to the set up temperature of the supplying hot-water eliminating the affect of the after boiling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply device provided with means for stabilizing the temperature of re-discharged hot water.

[0002]

2. Description of the Related Art FIG. 6 shows a schematic configuration of a conventional general hot water supply apparatus. In FIG. 1, a water supply pipe 2 of a water supply passage is connected to an inlet side of a hot water supply heat exchanger 1, and a water supply temperature sensor 3 for detecting a water supply temperature and a water supply flow rate (hot water supply flow rate) are connected to the water supply pipe 2. A flow sensor 4 is provided.

A hot water supply pipe 5 functioning as a hot water supply passage is connected to the outlet side of the hot water supply heat exchanger 1, and a hot water supply temperature sensor 6 for detecting the temperature of hot water from the hot water supply heat exchanger 1 is provided in the hot water supply pipe 5. A hot tap 7 is provided at the hot water supply destination of the hot water supply pipe 5.

[0004] A burner 8 is provided below the hot water supply heat exchanger 1, and a combustion fan (not shown) for supplying and exhausting air is provided below the burner 8. A remote control 11 is connected to the control device 10 for controlling the hot water supply operation, and the remote control 11 is provided with a temperature setting device for setting the hot water supply temperature, a display unit for the hot water supply temperature, and the like.

[0005] The control device 10 controls the hot water supply operation as follows. When the tap 7 is opened and the flow rate sensor 4 detects a flow rate equal to or greater than the operating flow rate, the combustion fan is rotated to supply gas to the burner 8 and operate ignition means (not shown) to burn the burner. I do. Then, the amount of gas combustion heat (gas supply amount) is controlled so that the hot water temperature detected by hot water temperature sensor 6 becomes the hot water supply set temperature set by remote controller 11, and hot water at the set temperature is supplied to hot water supply heat exchanger 1. The hot water is supplied to a desired hot water supply place such as a kitchen through the hot water supply pipe 5.

[0006] When the hot water has been used and the tap 7 is closed, the control device 10 receives the off signal from the flow sensor 4 to stop the combustion of the burner 8, and during the post-purge period (when the exhaust gas in the combustion chamber is exhausted). The combustion fan is stopped when the combustion fan is continuously rotated until the end of the period, and the preparation for the next hot water supply is stopped.

[0007]

However, when the temperature of the feed water entering the hot water supply heat exchanger 1 is low or when the set temperature of the hot water supply is low, the surface temperature of the water pipe of the hot water supply heat exchanger 1 becomes low. Then, a phenomenon occurs in which water vapor components in the exhaust gas generated by the combustion of the burner 8 touch the water pipe having a low temperature, and dew condensation occurs on the water pipe surface.

As described above, when dew is formed on the surface of the water pipe of the hot water supply heat exchanger 1, dirt and the like in the air sent from the combustion fan adhere to the dew condensation, thereby accelerating the clogging of the hot water supply heat exchanger 1. Failure occurs. In addition, components in the exhaust gas dissolve into the dew condensation, and the dew condensation takes on a strongly acidic property,
There is a problem that corrosion of the hot water supply heat exchanger 1 is accelerated and the life of the hot water supply heat exchanger 1 is shortened.

To solve the problem of the occurrence of dew condensation in the hot water supply heat exchanger 1, the applicant has developed a water supply system as shown in FIG. The equipment of this development is
The water supply pipe 2 and the hot water supply pipe 5 are connected and connected by a bypass passage 12, and a mixing ratio (mixing ratio) of the hot water and the water is continuously changed at a merging position of the water exiting the hot water supply heat exchanger 1 and the water exiting the bypass passage 12. A mixing adjustment means 13 comprising a possible motor valve or the like;
The configuration is such that the temperature of the mixed hot and cold water from the hot water 3 is detected by the hot water supply temperature sensor 6 as the hot water supply temperature.

In this development device, the hot water supply operation is performed by controlling the amount of combustion heat of the burner 8 by the control device 10 so that the hot water supply temperature detected by the hot water supply temperature sensor 6 becomes the hot water supply set temperature set by the remote controller 11. . According to the apparatus shown in FIG. 7, the water supplied from water supply pipe 2 is divided into a path passing through hot water supply heat exchanger 1 and a path passing through bypass passage 12, and the amount of water passing through hot water supply heat exchanger 1 is reduced. Thereby, the temperature of the hot water heated by the hot water supply heat exchanger 1 rises, and the temperature of the water pipe surface of the hot water supply heat exchanger 1 also rises, thereby preventing the occurrence of dew condensation. It can be eliminated.

Generally, when the hot water supply of the burner 8 is stopped and the burner 8 is burned again in a short time to restart the hot water supply, a problem arises in that hot water due to the post-boiling is discharged immediately after the start of the hot water return. There is. That is, after stopping the hot water supply combustion, the amount of residual heat retained in the hot water supply heat exchanger 1 is transmitted to the retained hot water in the hot water supply heat exchanger 1, and the so-called post-boiling causes the hot water in the hot water supply heat exchanger 1 to reach a high temperature. When hot water tap 7 is opened and hot water is re-started in that state, hot water in hot water supply heat exchanger 1 and bypass passage 12
The hot water cannot be lowered to the hot water supply set temperature only by the amount of water from the bypass passage 12, and the hot water is supplied from the hot water tap 7 to a hot water temperature higher than the hot water set temperature. There is a problem that the hot water flows out and makes the user of the hot water uncomfortable.

In a conventional general hot water supply apparatus, the feedforward heat quantity required for raising the feed water temperature detected by the feed water temperature sensor 3 to the hot water set temperature set by the remote controller 11 at the time of the spot ignition of the burner 8 is calculated. The amount of gas that generates the feedforward heat is supplied to the burner 8 to control the rising amount of the gas by so-called feedforward control.
The so-called proportional control supplies a gas amount corresponding to the total amount of the feedforward heat amount and the feedback heat amount that cancels out the difference between the detected temperature of the hot water supply temperature sensor 6 with respect to the set hot water temperature set by the remote controller 11. Controlling driving.

When the combustion operation is performed by such a control method, the time from when the hot water tap 7 is opened to when the burner 8 completes the ignition is extremely short. The hot water due to the post-boiling remains in the vessel 1.

As described above, when the control is shifted to the proportional control in a state where hot water due to post-boiling remains in the hot water supply heat exchanger 1,
The hot water supply temperature sensor 6 detects high-temperature hot water.
The amount of combustion heat is controlled to decrease, and the amount of combustion heat of water entering the hot water supply heat exchanger 1 from the water supply pipe 2 is insufficient. However, since the temperature of the hot water is considerably low, the temperature of the hot water supply becomes unstable due to the control of the hot water temperature by taking in the feedback heat quantity.

In order to eliminate such instability of the re-hot water temperature, at the start of the re-hot water temperature, the mixing ratio of the hot water and the water of the mixing adjusting means 13 is changed, and the mixing ratio of the water is increased. It is conceivable to suppress high-temperature hot water supply by post-boiling of the hot water supply heat exchanger 1.

However, even if an attempt is made to adjust the mixing ratio of hot water and water in the direction of eliminating post-boiling by adjusting the mixing ratio of the mixing adjusting means 13, after-boiling into the hot-water supply heat exchanger 1 after the burner 8 is ignited. When the hot water remains, a phenomenon occurs in which the boiling water is heated by the combustion of the burner 8 and the temperature of the hot water further rises. It is difficult, and there is a problem that it is not possible to prevent hot water from being discharged by reheating at the time of reheating. Even if hot water due to post-boiling does not remain at the time of spot ignition, if the temperature of the retained hot water in the hot water supply heat exchanger 1 is higher than the feed water temperature, the heat of combustion of the burner 8 sets the feed water temperature. Since the hot water is supplied with the amount of heat to make the temperature, the remaining hot water in the hot water supply heat exchanger 1 is heated to a temperature higher than the set hot water supply temperature, and the combustion heating of the burner 8 and the mixing adjustment of the mixing adjusting means 13 are performed. It is extremely difficult to match the timing with the above, and similarly, there is a problem that hot water higher than the set temperature is supplied.

In order to prevent such hot water supply, it is conceivable to delay the combustion of the burner 8 until the post-boiled water in the hot water supply heat exchanger 1 completely exits the hot water supply heat exchanger 1. However, in this case, when the burner 8 is ignited, the result is that the inside of the hot water supply heat exchanger 1 is filled with the water of the supply water temperature, so that even if the burner 8 is burned, the low-temperature hot water that is not sufficiently heated is supplied first. A problem arises.

As another means of stabilizing the temperature of the re-hot water, the post-boiler temperature in the hot water supply heat exchanger 1 after the stop of the hot water supply combustion and the volume of the post-boiler temperature in the heat exchanger 1 are measured when the hot water supply is stopped. From the standby time until the next hot-water discharge, the previous combustion heat amount, incoming water flow rate, incoming water temperature, hot water set temperature, outside air temperature, etc. It is conceivable to start the combustion of the burner 8 at the optimal timing before the gas exits from the hot water supply heat exchanger 1. However, the number of parameters for estimating and calculating the post-boil temperature and the volume of the post-boil water temperature is large. However, there is a problem that an arithmetic expression using the parameters becomes extremely complicated, and the circuit configuration of the arithmetic control becomes complicated accordingly, and it is difficult to obtain an accurate estimated value. Temperature and then boiling The temperature of the volume estimates, optimal burner 8
There is an uncertain factor that, even if an attempt is made to perform the ignition operation of the burner 8 at the combustion timing, it is not always possible to perform spot ignition at an accurate timing due to a response delay of a mechanism of an ignition system. It has been difficult to increase the control accuracy of the hot water temperature stabilization control.

The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a conventional control for eliminating the mismatch between the point ignition control of the burner 8 and the mixing timing of the hot and cold water of the mixing adjusting means 13. It is an object of the present invention to provide a hot water supply apparatus which can eliminate the complication of the configuration and can improve the stabilization accuracy of the re-hot water temperature with a simple control configuration.

[0020]

In order to achieve the above object, the present invention takes the following measures. That is,
In the first invention, a water supply passage provided with a flow rate sensor and a water supply temperature sensor is connected to an inlet side of a hot water supply heat exchanger heated by a hot water supply combustion of a burner, and a hot water supply passage is connected to an outlet side of the hot water supply heat exchanger. The water supply passage and the hot water supply passage are connected to each other by a bypass passage, and mixing adjustment means capable of continuously varying a mixing ratio between the amount of hot water flowing out of the hot water supply heat exchanger and the amount of water flowing out of the bypass passage is provided. In the hot water supply device that controls the combustion control and the mixing adjusting means so as to obtain hot water at the hot water set temperature set by the temperature setting device, the hot water supply standby time serving as a reference for performing the stabilization control of the hot water temperature is set. A data storage unit that stores data and data of a control mode switching time, which is a guide for finishing the after-boiled water in the hot water supply heat exchanger after the start of re-hot water supply, and a time for measuring an elapsed time since the stop of the hot water supply combustion. Measuring means; flow rate ratio detecting means for detecting a flow rate ratio between the amount of water passing through the hot water supply heat exchanger and the amount of water passing through the bypass passage; and Until the control mode switching time is reached, combustion control is performed only by feedforward control based on the feedforward heat quantity required to raise the feedwater temperature to the hot water set temperature, and after the control mode switching time has elapsed, the feedforward heat quantity and the feedback heat quantity A mode switching combustion control unit that performs combustion control by proportional control based on the total amount of heat, and the temperature information of the hot water at the outlet of the hot water heat exchanger or the temperature information of the hot water output through the mixing adjustment means, and the hot water temperature is set to the hot water setting temperature. Is calculated using an arithmetic expression given in advance to obtain the calculated flow ratio. And a means for solving the problems with the arrangement having a flow ratio controller for controlling the mixing ratio of the hot water and water in the mixing adjustment means.

According to a second aspect of the present invention, in accordance with the first aspect of the present invention, the data storage section includes a flow rate passing through the hot water supply heat exchanger during a steady operation and a bypass passage instead of the control mode switching time. The mode switching combustion control unit stores the data of the allowable range for the set flow ratio with the flow rate passing through, and the flow ratio detected by the flow ratio detecting means after the start of re-hot water deviates from the allowable range for the set flow ratio. During this period, the combustion control is performed only by the feedforward control based on the feedforward heat, and after the detected flow rate ratio falls within the allowable range, the combustion control is performed by the proportional control based on the total heat of the feedforward heat and the feedback heat. The above configuration is a means for solving the problem.

According to a third aspect of the present invention, a water supply passage provided with a flow rate sensor and a water supply temperature sensor is connected to an inlet side of a hot water supply heat exchanger heated by a hot water supply combustion of a burner, and is connected to an outlet side of the hot water supply heat exchanger. A hot water supply passage is connected, and the water supply passage and the hot water supply passage are connected to each other by a bypass passage having no passage opening / closing valve and a bypass passage having a passage opening / closing valve, respectively. A hot water supply device that controls combustion and controls the opening and closing valve of a bypass passage so as to obtain a hot water standby time as a reference for stabilizing control of hot water temperature and hot water heat exchange after the hot water starts. The data of the control mode switching time, which is a guide to the end of the after-boiled water in the heater, and the data of the hot water supply heat exchanger side and both bypass passage sides when the on-off valve of the bypass valve is opened and closed, respectively. Flow ratio data A data storage unit in which the hot water supply is stopped, time measuring means for measuring an elapsed time from when the hot water supply is stopped, and when the hot water supply is started within the hot water supply standby time after the stop of the hot water supply, the control is performed. Until the mode switching time is reached, combustion control is performed only by feedforward control based on the feedforward heat quantity required to raise the feedwater temperature to the hot water set temperature, and after the control mode switching time has elapsed, the feedforward heat quantity and the feedback heat quantity A mode switching combustion control unit that performs combustion control by proportional control based on the total amount of heat, and a flow ratio for taking the temperature information of the hot water at the outlet side of the hot water heat exchanger for each sampling time and setting the hot water temperature to the hot water set temperature. The open time of the on-off valve of the bypass passage is determined using solution data given in advance. With a configuration having a flow ratio controller for controlling the opening time of the valve closing at each sampling time are a means to solve the problems.

In a fourth aspect based on the configuration of the third aspect, the mode-switching combustion control section replaces the control based on the control mode switching time with a bypass passage controlled by the flow rate control section. While the open time is out of the minute time range given in advance, the combustion control is performed only by the feedforward control based on the feedforward calorie, and after the open time falls within the minute time range or becomes zero, This is a means for solving the problem with a configuration in which combustion control is performed by proportional control based on the total heat amount of the feedforward heat amount and the feedback heat amount.

[0024] In the invention having the above-mentioned structure, in the invention provided with the mixing adjusting means for varying the mixing ratio of the amount of hot water flowing out of the hot water supply heat exchanger and the amount of water flowing out of the bypass passage, after the start of re-water supply, The temperature of the hot water at the outlet of the exchanger or the hot water temperature of the hot water supplied through the mixing adjusting means is taken in, and the mixing ratio of the hot water and the water of the mixing adjusting means is adjusted so that the flow rate becomes the hot water supply temperature to the hot water set temperature. It is controlled by the flow ratio control unit. On the other hand, by the mode switching combustion control unit, when the control mode switching time, which is a guide for finishing the post-boiled water in the hot water supply heat exchanger after the start of re-hot water supply, has elapsed, or Combustion control using only feedforward control based on feedforward heat when the flow ratio of the flow rate through the hot water supply heat exchanger and the flow rate through the bypass passage is almost within the allowable range for the set flow rate Then, the process shifts to proportional control based on the total heat amount of the feedforward heat amount and the feedback heat amount.

As described above, the control using the feedback heat amount, which is an unstable factor, is not performed until the post-boiled water in the hot water supply heat exchanger is almost completely discharged, and only the feedforward control based on the feedforward heat amount is performed. Since the combustion control is performed and the mixing adjusting means controls the mixing ratio of the hot water and the water so that the hot water discharged from the mixing adjusting means has the hot water supply set temperature, the post-boiled residual hot and cold water in the hot water supply heat exchanger. The hot water of the set temperature is discharged by the hot water / water mixing control of the mixing adjusting means, and new water entering the hot water supply heat exchanger 1 is fed forward required to raise the feed water temperature to the set temperature. Since the amount of combustion heat is controlled on the basis of the amount of heat, unstable elements of combustion control due to fluctuations in the amount of feedback heat are completely removed, and as a result, a stable Tapping is possible.

After the post-boiled remaining hot water in the hot water supply heat exchanger 1 is almost completely discharged, the mixing ratio of the hot water and the water of the mixing adjusting means is adjusted at a stable set flow ratio, and the flow ratio is adjusted. The combustion calorie shifts to a steady combustion operation by proportional control based on the total calorie of the feedback calorie and the feedforward calorie, and the hot water is supplied at a stable temperature.

Further, in a configuration in which a bypass passage having no on-off valve and a bypass passage having an on-off valve are provided in place of the mixing adjusting means, the post-boiled water remains in the hot water supply heat exchanger. At the time of starting the hot water re-starting, a short time before the control mode switching time, which is a guide for the end of the post-boiled hot water, or the opening time by the on-off valve of the bypass passage controlled by the flow ratio control unit is given in advance. While the temperature is out of the range, the combustion control is performed only by the feedforward control based on the feedforward calorie, while the opening time of the bypass passage is controlled by the flow rate control unit so that the hot water temperature becomes the set temperature. Therefore, the hot water from the hot water supply heat exchanger is controlled by the flow rate ratio control unit to control the opening time of the bypass passage. The mixing ratio of water is adjusted so that the hot water flows out, and the mode switching combustion control unit feeds the feedforward heat based on the feedforward heat quantity required to turn the feedwater entering the hot water heat exchanger into hot water at the set temperature. Since the combustion heat amount is controlled only by the control, there is no unstable element of the combustion control due to the fluctuation of the feedback heat amount, and hot water having a stable set temperature can be supplied at the start of re-water supply.

Further, after the post-boiled water has almost completely exited the hot water supply heat exchanger, when the control mode switching time has elapsed, or since the opening time of the bypass passage has entered a minute time range given in advance, the feedforward heat quantity The control shifts to the proportional control in the steady operation state based on the total calorific value of the feedback calorie and the calorific value.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows a system configuration of an embodiment of the hot water supply apparatus using the mixing adjusting means 13, and the same parts as those of the system shown in FIG. Characteristic features of the system according to this embodiment are that a flow rate sensor 14 is provided in the bypass passage 12, and that the temperature of the hot water supplied from the hot water supply heat exchanger 1 is detected on the outlet side of the hot water supply heat exchanger 1. The configuration is the same as that of the system shown in FIG. 7 except that an exchange outlet temperature sensor 15 is provided.

In this embodiment, the mixing adjusting means 1
Reference numeral 3 denotes a configuration in which the relationship between the control operation amount or control operation position and the mixing adjustment ratio of hot water and water corresponds to 1: 1. For example, when the adjusting mechanism for adjusting the mixing ratio of hot water and water is of a rotation control type using a motor, the relationship between the rotation angle of the motor and the flow ratio of the mixing ratio is determined in advance as data, and the encoder and the volume are adjusted. It is possible to adopt a configuration in which the rotation angle of the motor at the control operation position is detected, and a configuration in which the mixing ratio is detected and controlled by detecting the rotation angle of the motor, or from the home position which is the reference position of the motor. The relationship between the operation time and the flow ratio can be obtained in advance, and the mixing ratio can be detected and controlled based on the operation direction and operation time from the home position. Further, a stepping motor can be used as the motor. Is used to detect the mixing ratio (flow ratio) based on the number of operation pulses for driving the stepping motor and the rotation angle per pulse. It is also possible to structure the thing.

The present embodiment employs a simple control structure to provide a unique control structure for stabilizing the temperature of the refilled hot water.
The specific control configuration is shown in the block diagram of FIG. The configuration of the first embodiment of this unique control configuration includes a feedforward heat amount setting unit 16 and a feedback heat amount setting unit 17.
, Time measuring means 18 and mode switching combustion control unit 2
0, a flow ratio detection unit 21, a flow ratio control unit 22, and a data storage unit 23.

The feedforward calorie setting means 16 includes a feedwater temperature T _IN detected by the feedwater temperature sensor 3, a hot water set temperature _Tst set by the temperature setter of the remote controller 11, and a feedwater flow rate detected by the flow sensor 4. Based on the detection data of Q, the theoretical amount of heat required to raise the feedwater temperature to the set temperature is set as the feedforward heat amount P _{F / F by the} following equation (1).

P _{F / F =} Q (T _st −T _IN ) / η (1)

In the above equation (1), η is the thermal efficiency of the hot water supply heat exchanger 1.

The feedback heat amount setting means 17 sets a feedback heat amount P _{F / B} for canceling a deviation of the hot water supply temperature T _MIX detected by the hot water supply temperature sensor 6 from the hot water supply set temperature T _st . The time measuring means 18 measures the elapsed time from the stop of the hot water supply combustion to the start of the next hot water supply and the elapsed combustion time from the start of the hot water supply again.

The data storage unit 23 is used as a reference for performing the stabilization control of the re-hot water temperature, and serves as a reference when the re-hot water standby time and the post-boiled hot water in the hot water supply heat exchanger 1 after the re-water supply starts. The data of the control mode switching time and the data of the set flow ratio of the flow rate through the hot water supply heat exchanger 1 and the flow rate of the water flowing through the bypass passage 12 during the steady operation of hot water supply are stored. As the data of the re-watering standby time, for example, time data of 5 minutes is given, and when the re-watering start after the stop of hot water supply combustion is performed within the re-watering standby time, stabilization of the re-watering hot water temperature is performed. If hot water supply combustion is started after the stop of hot water supply combustion and hot water supply combustion is started, it is determined to be in a cold start state, and stabilization control of the hot water supply hot water temperature is not performed. This means a time serving as a reference for determining whether or not to perform the stabilization control of the tap water temperature.

The data of the control mode switching time is given as time data when the residual water amount in the hot water supply heat exchanger 1 almost ends from the start of re-water supply. For example, the residual water amount in the hot water supply heat exchanger 1 is The time until the water is completely discharged, or the time until the flow of a predetermined ratio (for example, 90%) of the residual water amount in the hot water supply heat exchanger 1 is completed, or the output of the hot water supply heat exchanger 1 corresponding to the set hot water supply temperature. Data such as the elapsed time from the start of re-watering until the temperature drops to a temperature higher by a temperature α (for example, 3 ° C.) given in advance with respect to the target hot water temperature on the side is obtained in advance through experiments and the like.

The data of the set flow ratio is given at the design stage or the like as the value of the optimum flow ratio during the steady operation of hot water supply. That is, if the ratio of the flow rate passing through the bypass passage 12 is too large, the flow rate passing through the hot water supply heat exchanger 1 becomes extremely small, causing a problem that the hot water passing through the hot water supply heat exchanger 1 causes boiling. Conversely, if the ratio of the flow rate passing through the hot water supply heat exchanger 1 is too large, the temperature of the surface of the water pipe of the hot water supply heat exchanger 1 becomes low, causing a problem that dew condensation occurs on the water pipe surface. The optimal set flow ratio between the hot water supply heat exchanger 1 and the bypass passage 12 which does not cause such condensation or boiling is given by, for example, data of 7: 3 or 8: 2.

The mode switching combustion control unit 20 receives the result of the time measurement by the time measuring unit 18, and performs re-watering within the range of the re-watering standby time stored in the data storage unit 23 from the time of stopping the hot water supply combustion. In some cases, the time from the start of hot water supply is measured by the time measuring means 18 and the feedforward heat amount P _F set by the feedforward heat amount setting means 16 until the control mode switching time stored in the data storage unit 23 is reached. _{/ F} multiplied by a predetermined ratio α (for example, 1.0 for 100%, 0.9 for 90%). In this embodiment, α is 10
The heat amount set by the feedforward heat amount setting means 16 is used as it is, and combustion control (gas supply amount control) is performed so as to generate the feedforward heat amount P _{F / F.} After the start of combustion of the hot water, after the control mode switching time has elapsed, the feedforward heat amount P set by the feedforward heat amount setting means 16 is set.
_The combustion control is performed so as to generate a total heat amount of the feedback heat amount PF _{/ B} set by the feedback heat amount setting means 17.

The flow ratio detecting means 21 determines the flow rate passing through the hot water supply heat exchanger 1 and the flow rate of the bypass passage 12 based on the data of the total feed water flow rate detected by the flow rate sensor 4 and the flow rate of the bypass passage 12 detected by the flow rate sensor 14. The flow ratio of the flow passing through is calculated and detected. For example, the total water supply flow rate detected by the flow rate sensor 4 is Q, and the flow rate detected by the flow rate sensor 14 is q ₂
, The flow rate q ₁ passing through the hot water supply heat exchanger ₁ is q _{1 =} Q
The -q _2. Accordingly, the ratio of flow rate to the total feed water flow through the hot water supply heat exchanger 1 side through q ₁ / Q, and the similarly bypass passage 12 to the total feed water flow rate q ₂
/ Q, and the ratio of the flow rate passing through the hot water supply heat exchanger 1 side to the flow rate passing through the bypass passage 12 side is q ₁ / Q: q ₂ / Q = q ₁ :
a q _2.

The flow ratio controller 22 has a flow ratio calculator,
Hot water supply temperature T _MIX detected by hot water supply temperature sensor 6 or data of hot water temperature T _OUT on the outlet side of hot water supply heat exchanger 1 detected by heat exchange outlet temperature sensor 15 and water supply detected by water supply temperature sensor 3 Based on the temperature T _IN and the hot water supply set temperature T _st set by the temperature setting device, the mixing ratio of the hot water and the water of the mixing adjusting means 13 is calculated by operation so that the hot water supply temperature becomes the hot water set temperature, and the obtained flow rate ratio Mixing adjusting means 1 so that
3 is controlled. For example, the heat exchange outlet temperature sensor 1
When calculating the flow rate ratio using T _OUT of 5, the following (2)
Use the formula.

T _st = T _OUT × a + T _IN (1-a) (2)

First, a flow ratio a (a = q ₁ / Q) with respect to the total water supply flow rate on the hot water supply heat exchanger 1 side is obtained by using the equation (2). The ratio of the flow rate to the total flow rate of the feedwater passing through the bypass passage 12 is 1-a, and the flow rate ratio between the flow rate passing through the hot water supply heat exchanger 1 and the flow rate passing through the bypass passage 12 is obtained as a: (1-a). The flow ratio of the mixing adjusting means is controlled so as to obtain the flow ratio.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, when hot-water supply combustion starts, it is determined whether the hot-water supply combustion is the operation state of re-hot water supply within the re-water supply standby time after the previous stop of hot-water supply combustion, or hot water supply by cold start after the elapse of the hot water supply standby time. I do.

At the time of hot water supply operation for re-water supply, step 1
In step 02, the ignition operation is performed, and in step 103, it is determined whether or not the control mode switching time has elapsed since the start of hot water supply / combustion. If the control mode switching time has not elapsed, in the next step 104, the hot water supply temperature T _MIX
Is determined to be the hot water supply set temperature T _st , and if the hot water supply temperature is not equal to the set temperature, the mixing adjustment means 13 in the next step 105 so that the hot water supply temperature becomes the hot water supply set temperature.
To control the flow ratio. In this flow ratio control, the flow ratio is calculated using the temperature of the hot water on the outlet side of the hot water supply heat exchanger 1 detected by the heat exchange outlet temperature sensor 15. When the flow rate ratio is controlled and in step 104, the hot water supply temperature T
When it is determined that _MIX is equal to the hot water supply set temperature T _st , in step 106, the feedforward heat amount setting means 16
In controlling the set is heat of combustion of the feed-forward heat P _{F /} feedforward heat multiplied by the ratio α previously given to _F P _{F / F} to based only on the amount of heat that is based burner 8.

The combustion control based only on the heat amount based on the feedforward heat amount P _{F / F} repeats the operations from step 103 to step 106 until the elapsed time from the start of the re-hot water combustion reaches the control mode switching time. Is done continuously. When it is determined in step 101 that the hot water supply combustion is in the cold start state, the ignition operation is performed in step 107, and the feedforward heat amount P _{F / F} feedback heat amount in step 108 and thereafter is performed without performing the stabilization control of the hot water. The combustion control of the burner 8 is performed by the proportional control based on the total heat quantity of P _{F / B.}

After the start of the hot-water discharge combustion in step 103,
When it is determined that the control mode switching time has elapsed, in step 112, the hot water supply temperature T _MIX is changed to the hot water supply set temperature T.
It is determined whether or not it is equal to _{st. If} not, the flow rate ratio of the mixing adjusting means 13 is controlled in step 113 so that the hot water supply temperature becomes the hot water supply set temperature. And
At step 114, it is determined whether or not the flow rate ratio has reached the set flow rate ratio. If the flow rate ratio has not reached the set flow rate ratio, the operations from step 112 to step 114 are repeated.
Then, when the flow ratio reaches the set flow ratio, the flow shifts to combustion control by proportional control in step 108 and thereafter.

When it is determined in step 112 that the hot water supply temperature is equal to the hot water supply set temperature, in step 115, the flow ratio between the flow rate passing through the hot water supply heat exchanger 1 and the flow rate passing through the bypass passage 12 is determined. It is determined whether or not the set flow ratio has been reached. If the set flow ratio has not been reached, the flow ratio is controlled to the set flow ratio, and the operation from step 108 is performed. Also, when it is determined in step 115 that the flow ratio is equal to the set flow ratio, the operation similarly proceeds to step 108 and thereafter.

As described above, the proportional control in step 108 is based on the total of the feed forward heat amount P _{F / F} set by the feed forward heat amount setting means 16 and the feedback heat amount P _{F / B} set by the feedback heat amount setting means 17. The amount of heat of combustion of the burner 8 is controlled by the amount of heat.
In step 109, it is determined whether or not the hot water supply temperature has reached the hot water supply set temperature. If the hot water supply temperature is not equal to the hot water supply set temperature, the combustion heat amount is controlled by the proportional control in step 108 so that the hot water supply temperature becomes the hot water supply set temperature. When it is determined in step 109 that the hot water supply temperature is equal to the hot water supply set temperature, it is determined whether or not the running water is turned off based on the detection signal of the flow rate sensor 4. It is determined that the combustion operation is being performed, and the operations from step 108 to step 110 are repeatedly performed. Then, when running water is detected to be off in step 110, it is determined that the hot water tap 7 is closed, and in step 111, combustion is stopped to prepare for the next hot water supply.

According to the present embodiment, during the period in which it is assumed that the temperature of the hot water in the hot water supply heat exchanger 1 after the start of re-hot water supply and the hot water in the hot water is almost completely discharged, the control by the feedback heat quantity is performed. And feed-forward heat P
_{Since the} combustion control is performed only by the feedforward control based on the _{F / F} , the feedwater entering after the post-boiled water exits the hot water supply heat exchanger 1 is set by the feedforward heat quantity. The hot-water of the post-boiling is mixed with the water by controlling the flow ratio so that the hot-water supply temperature becomes the hot-water supply set temperature by the mixing adjusting means 13. Is eliminated, and stable hot water supply with little change in hot water temperature can be supplied.

Further, there is no need for complicated control of the amount of combustion based on the amount of feedback heat at the start of re-hot water supply, and only the supply of heat based on the amount of feedforward heat needs to be controlled. Since no adjustment is required, the control structure for the amount of combustion heat is extremely simplified.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the control mode is switched from feedforward control to proportional control based on the flow rate ratio between the flow rate on the hot water supply heat exchanger 1 side and the flow rate on the bypass passage 12 side detected by the flow rate ratio detecting means 21. The other configuration is the same as that of the first embodiment. In the second embodiment, as shown by the broken line in FIG. 1, the flow ratio detection information of the flow ratio detection means 21 is applied to the mode switching combustion control unit 20. The data storage unit 23 stores data of an allowable range for the set flow rate ratio, in addition to the set flow rate ratio.

The mode switching combustion control unit 20 controls the feedforward heat amount P _F set by the feedforward heat amount setting unit 16 while the flow ratio detected by the flow ratio detection unit 21 is out of the allowable range of the set flow ratio. The combustion heat of the burner 8 is controlled only by the feed forward control based on the feed forward heat P _{F / F} obtained by multiplying the ratio α by the ratio α _{/ F} , and the flow ratio detected by the flow ratio detecting means 21 is allowed for the set flow ratio. After entering the range, the feedforward heat amount PF _{/ F} set by the feedforward heat amount setting means 16 and the feedback heat amount setting means 1
The combustion heat amount of the burner 8 is controlled by proportional control of the total heat amount of the feedback heat amount P _{F / B} set in step 7.

After the start of re-hot water supply, as described above, the post-boiled water remains in the hot water supply heat exchanger 1, and when this hot water exits from the hot water supply heat exchanger 1, the flow ratio control unit 22 Controls the flow ratio of hot water and water in the mixing adjustment means 13,
Until the post-boiled water has almost completely exited the hot water supply heat exchanger 1, the flow rate detected by the flow ratio detecting means 21 is increased in order to increase the mixing ratio of the water flowing out of the bypass passage 12 in order to eliminate the high temperature of the post-boil. The ratio is out of the allowable range given to the set flow rate ratio. In this state, that is, in a period before the post-boiled water is almost completely discharged from the hot water supply heat exchanger 1, the feedforward heat amount P _{F / Since the} combustion control is performed only by the feedforward control based on _F and the control based on the feedback heat quantity which is an unstable factor is not performed, the combustion control is stabilized.

Then, similarly to the first embodiment, the post-boiled hot water is supplied at the set hot water supply temperature by controlling the mixing ratio of the hot water and the water by the mixing adjusting means 13 by the flow ratio control unit 22. The flow ratio is controlled and the hot water supply heat exchanger 1
Since the feed water that enters after the hot water is discharged from the hot water is heated by the feedforward heat amount PF _{/ F} required to raise the feed water temperature to the set temperature, the hot water is completely discharged from the hot water supply heat exchanger 1. It is possible to prevent the supply of newly supplied hot water having a temperature lower than the set hot water supply temperature due to insufficient heating of newly supplied hot water after the hot water supply, thereby enabling a stable hot water supply.

When the post-boiled water in the hot water supply heat exchanger 1 has almost completely exited, the flow ratio of the mixing adjusting means 13 controlled by the flow ratio control unit 22 approaches the set flow ratio. Since it falls within the allowable range given to the flow rate ratio, thereafter, the combustion operation can stably transition by proportional control based on the total heat quantity of the normal feed forward heat quantity and the feedback heat quantity.

In the first and second embodiments, the flow rate sensor 14 for detecting the flow rate ratio is provided on the side of the bypass passage 12, but this is replaced with the hot water supply heat exchange as shown by the chain line in FIG. It may be provided on the vessel 1 side.

The flow ratio detecting means 21 calculates the flow ratio based on the flow rates detected by the flow sensors 4 and 14, but detects the operating state of the flow ratio adjustment by the mixing adjusting means 13 and mixes the hot water side and the water side. The flow ratio may be detected.

Further, until the post-boiled water is almost completely discharged from the hot water supply heat exchanger 1, that is, before the elapsed time from the start of re-water supply reaches the control mode switching time, or the flow ratio is given to the set flow ratio. During the period when the temperature is out of the allowable range, the temperature detected by the heat exchange outlet temperature sensor 15 is taken in and the mixing adjusting means 1 is adjusted so that the hot water supply temperature becomes the hot water supply set temperature.
Although the mixing ratio of hot water and water was controlled, instead of the heat exchange outlet temperature sensor 15, the detection temperature of the hot water supply temperature sensor 6 was taken in, and the hot water and water of the mixing adjusting means 13 were adjusted so that the hot water temperature reached the hot water supply set temperature. It is also possible to control the mixing ratio of.

FIG. 4 shows a system configuration of a third embodiment of the present invention. In the system according to the third embodiment, the bypass passages 12a and 12a are provided between the water supply pipe 2 and the hot water supply pipe 5.
b, the bypass passage 12a is a continuous bypass passage having no on-off valve, and the bypass passage 12b
Is a bypass passage provided with an on-off valve provided with an on-off valve 24 for opening and closing the passage. The mixing ratio of hot water from the hot water supply heat exchanger 1 and water from the bypass passages 12a and 12b is controlled by opening and closing the on-off valve 24. Is controlled, and
Other configurations are the same as those of the first embodiment, and the same parts as those of the system configuration shown in FIG.

In the third embodiment, the data storage unit 23 shown in FIG. 1 stores, in addition to the data of the re-watering standby time and the data of the control mode switching time, the hot water supply heat exchanger when the on-off valve 24 is open. The data on the flow rate ratio between the flow rate on the side 1 and the flow rates on the bypass passages 12a and 12b and the data on the flow rate ratio between the flow rate on the hot water supply heat exchanger 1 and the flow rate on the bypass path 12a when the on-off valve 24 is closed are previously stored. Is stored. The configurations and operations of the feedforward calorie setting unit 16, the feedback calorie setting unit 17, the time measuring unit 18, the mode switching combustion control unit 20, and the flow ratio detecting unit 21 are the same as those of the first embodiment.

The flow rate control unit 22 uses the timer 25 to take in the detection information of the heat exchange outlet temperature sensor 15 at every sampling time (for example, one second) given in advance. And
The opening time Δt of the on-off valve 24 with respect to each sampling time is calculated using the relational data of the following equation (3), and the on-off valve 24 is turned on at each sampling time using the data of Δt obtained at each sampling time. The opening operation is controlled only for the time.

[0063] _{T st = {(t s -Δt} ) / t s} {T OUT (1-Boff) + T IN · Boff} + (Δ t / t s) {T OUT (1-B ON) + T IN · B _ON ｝ ... (3)

[0064] Incidentally, (3) the formula, t _s is the sampling time, Boff is the flow rate of the bypass passage 12a to the total feed water flow rate when the opening and closing valve 24 is closed, B _ON is off valve 24
Respectively show the flow ratios of the two bypass passages 12a and 12b to the total supply water flow rate when is turned on (open).

FIG. 5 shows an operation for stabilizing the temperature of the refilled hot water according to the third embodiment. Curve A in the graph of FIG. 5 shows the temperature of the hot water on the outlet side of the hot water supply heat exchanger 1 detected by the heat exchange outlet temperature sensor 15 after the start of re-hot water supply, and curve B shows the on-off valve 24 closed. The hot water supply temperature at this time (the temperature detected by the hot water supply temperature sensor 6) is shown.
Shows the hot water supply temperature when is opened.

In the example of FIG. 5, the hot water supply temperature is set to 40 ° C. At this time, when the on-off valve 24 is closed, the hot water in the hot water supply heat exchanger 1 for discharging hot water at the hot water supply set temperature is set. The target temperature is 50 ° C., and as is apparent from the curve A, after the re-start of hot water supply, the hot water supply heat exchanger 1 outputs the target temperature of 50 ° C.
It indicates that boiling water comes out after passing.

The flow ratio control unit 22 detects the temperature of the hot water on the outlet side of the hot water supply heat exchanger 1 at every sampling time after the start of re-water supply, and opens and closes the on-off valve 24 so that the hot water temperature reaches the hot water supply set temperature.
The open time Δt is calculated, and the open / close valve 24 is controlled to be opened for the open time at each sampling time. In the example of FIG. 5, the opening time of the on-off valve 24 gradually increases as the post-boiler temperature rises after the start of re-hot water supply, and as the post-boiler temperature peaks, the opening time gradually decreases and the hot water supply heat increases. When the post-boiled water in the exchanger 1 is almost completely discharged, the opening time Δt converges to near zero.

A curve F in FIG. 5 shows the temperature at which hot water is supplied by controlling the opening operation of the on-off valve 24 (the temperature detected by the hot water supply temperature sensor 6).
When the open / close valve 24 is closed, the hot water temperature fluctuates up and down with respect to the hot water set temperature of 40 ° C. along the curve B. However, the hot water on the hot water supply heat exchanger 1 side and the hot water on the bypass passages 12a and 12b side As the water is mixed and passes through the pipeline leading to the hot water tap 7, the stirring of the hot water and the water is promoted, and the temporal fluctuation of the hot water temperature is gradual. Hot water temperature characteristics are achieved, and stable hot water supply with hot water is possible.

Also in the third embodiment, the burner is controlled only by the feedforward control based on the feedforward heat quantity before the control mode switching time until the post-boiled water in the hot water supply heat exchanger 1 is almost completely discharged. 8, the after-boiled water in the hot-water supply heat exchanger 1 is turned off by the opening and closing control of the on-off valve 24, as described above.
With a simple control configuration similar to the first and second embodiments, it is possible to supply a stable hot-water temperature.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, instead of switching the combustion control mode using the control mode switching time, the mixing flow ratio of hot water and water of the mixing adjusting means 13 controlled by the flow ratio control unit 22, that is, each sampling The control mode is switched between the feedforward control and the proportional control using the data of the opening time Δt of the on-off valve 24 obtained for each time. The other configurations are the same as those of the third embodiment. The same is true.

In the fourth embodiment, a minute time range of the on-off valve 24 is stored in advance in the data storage section 23 of FIG. The mode switching combustion control unit 20 includes the flow ratio control unit 2
The information of the opening time Δt of the on-off valve 24 calculated in step 2 is fetched for each sampling time, and it is monitored whether or not the calculated opening time Δt falls within the short time range given to the data storage unit 23. Then, while the opening time Δt is out of the minute time range, it is determined that the post-boiled water comes out of the hot water supply heat exchanger 1 and that the influence thereof appears, and the feed rate set by the feed forward heat amount setting means 16 is determined. The forward heat quantity P _{F / F} is assigned to the ratio α (1.0 (100 in this embodiment).
%)), The combustion calorie of the burner 8 is controlled only by the feedforward control of the calorie. As the post-boiled water in the hot water supply heat exchanger 1 comes out and its influence is reduced, the opening time Δt of the on-off valve 24 calculated by the flow ratio control unit 22 gradually approaches zero, and enters the minute time range. Open time Δt
After entering into the minute time range, it is determined that the influence of the post-boiled water is no longer generated, and the feedforward heat amount PF _{/ F} and the feedback heat amount PF _{/ B} are determined from the feedforward control. The combustion control of the burner 8 is performed by switching to the proportional control based on the added total heat amount.

Also in the fourth embodiment, during the period in which the effect of the post-boiled water in the hot water supply heat exchanger 1 occurs, the control using the feedback heat amount is not performed and the feedforward heat amount P _{F / F} is used as the base. Since the combustion control is performed only by the calorific value, the instability of the combustion calorie control is eliminated, and the first
As in the third to third embodiments, it is possible to supply hot water at a stable temperature. In the fourth embodiment, the feedforward control is switched to the proportional control when the opening time Δt of the on-off valve 24 enters the minute time range. However, the feedforward control is performed after the opening time Δt becomes zero. The control may be switched to the proportional control. Also, the minute time range is not in the range of just a time may be given by the time value of the percentage of opening time Delta] t for the sampling period _{t s (Δt / t s)} . In this case, the open time Δt obtained from the flow ratio control unit 22 is changed to the sampling time t _s
Seeking divided by the, and thus switching the control mode of combustion based on whether the obtained value is within the minute time range Δt / t _s.

Note that the present invention is not limited to the above embodiments, but can adopt various embodiments. For example, in the third and fourth embodiments, the bypass valve 12b provided with the on-off valve 24 is one (one), but a plurality of bypass valves 12b may be provided. Of course, it is also possible to provide a plurality of always-bypass passages 12a without the on-off valve 24. Further, the on-off valve 24 may be any valve that can open and close the passage by a control signal, and may be a solenoid valve as well as other valves using, for example, a diaphragm, and may be configured using various forms of control valves. Is possible.

[0074]

According to the present invention, after the start of reheating, the effect of the post-boiled water in the hot water supply heat exchanger is exerted, that is, before the control mode switching time is reached after the start of reheating, or in the hot water supply heat exchanger side. During the period when the detected flow ratio between the flow rate and the flow rate flowing through the bypass passage is out of the allowable range given to the set flow rate ratio, avoid the control by the feedback heat quantity, which makes the control of the re-hot water temperature unstable, and Since the combustion control is performed only by the feed forward control based on the forward calorie, the calorie control at the start of re-hot water is extremely stabilized.

Then, the mixing ratio of the hot water and the water of the mixing adjusting means is controlled by the flow rate ratio control unit so that the hot water remains at the hot water supply heat exchanger at the start of re-water supply. Therefore, the feedwater temperature that is caused by the post-boiled water is eliminated, and the feedwater that enters after the post-boiled water comes out is fed-forward control based on the feedforward heat quantity required to raise the feedwater temperature to the hot water set temperature. As a result, the temperature of the hot water is set to the set hot water supply temperature, so that it is possible to prevent the undershoot hot water lower than the hot water supply set temperature from flowing after the post-boiled hot water is discharged, and it is possible to supply the hot water at a stable hot water temperature.

Further, after the period in which the influence of the post-boiled hot water at the start of the re-hot water supply has passed, the mixing ratio (flow ratio) of the hot water and the water of the mixing adjusting means is maintained at the steady set flow ratio, and The temperature control shifts to proportional control based on the total heat quantity of the feedforward heat quantity and the feedback heat quantity, and the control mode is switched smoothly from the feedforward control to the proportional control.

Further, a bypass passage having no on-off valve and a bypass passage having an on-off valve are provided between the water supply passage and the hot water supply passage, and the opening time of the on-off valve provided in the bypass passage is controlled to mix hot water and water. Even in the invention in which the ratio is controlled, during the period in which the effect of the post-boiled water in the hot water supply heat exchanger is exerted, the combustion heat amount is controlled only by the feed forward control based on the feed forward heat amount. Since the temperature is eliminated by controlling the opening time of the on-off valve, it is possible to supply the hot water at the same temperature.

Further, during the period in which the effect of the post-boiled water in the hot water supply heat exchanger is exerted, control only by feedforward control based on the feedforward calorie may be performed. Since fine adjustment control is not required, the configuration of the combustion control becomes extremely simple, and an excellent effect of inexpensively providing the hot water supply apparatus having the excellent re-discharging hot water temperature stabilizing effect of the present invention is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of each embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a system configuration according to a second and a third embodiment of the present invention;

FIG. 4 is an explanatory diagram of a system configuration according to third and fourth embodiments of the present invention.

FIG. 5 is an explanatory diagram of stabilization control of re-discharged hot water temperature by controlling the opening time of an on-off valve in the third and fourth embodiments.

FIG. 6 is an explanatory diagram of a system of a conventional general hot water supply apparatus.

FIG. 7 is an explanatory diagram of a system of a hot water supply device provided with a control system for stabilizing the temperature of refilling hot water developed by the applicant.

[Explanation of symbols]

 12, 12a, 12b Bypass passage 13 Mixing adjustment means 14 Flow rate sensor 15 Heat exchange outlet temperature sensor 16 Feed forward heat quantity setting means 17 Feedback heat quantity setting means 20 Mode switching combustion control unit 21 Flow rate detection means 22 Flow rate control unit 24 On-off valve

Claims (4)

[Claims] 1. A hot water supply passage provided with a flow rate sensor and a hot water supply temperature sensor is connected to an inlet side of a hot water supply heat exchanger heated by hot water supply combustion of a burner, and a hot water supply passage is connected to an outlet side of the hot water supply heat exchanger. The water supply passage and the hot water supply passage are connected to each other by a bypass passage, and mixing adjustment means capable of continuously changing a mixing ratio between the amount of hot water flowing out of the hot water supply heat exchanger and the amount of water flowing out of the bypass passage is provided. In the hot water supply device that controls the combustion control and the mixing adjustment means so as to obtain hot water at the hot water set temperature set by the temperature setting device, the data of the hot water standby time as a reference for performing the stabilization control of the hot water temperature. And a data storage unit that stores data of a control mode switching time, which is a guide for finishing the after-boiled water in the hot water supply heat exchanger after the start of re-hot water supply, and a time meter that measures an elapsed time from when the hot water supply combustion stops. Measuring means, flow rate ratio detecting means for detecting a flow rate ratio between the amount of water passing through the hot water supply heat exchanger and the amount of water passing through the bypass passage, and when the restart of hot water is started within the second hot water standby time after the stoppage of combustion of the hot water, Until the control mode switching time is reached, combustion control is performed only by feedforward control based on the feedforward heat quantity required to raise the feedwater temperature to the hot water supply set temperature, and after the control mode switching time has elapsed, the feedforward heat quantity and the feedback heat quantity A mode switching combustion control unit that performs combustion control by proportional control based on the total amount of heat, and the temperature information of the hot water at the outlet of the hot water heat exchanger or the temperature information of the hot water output through the mixing adjustment means, and the hot water temperature is set to the hot water setting temperature. Is calculated using an arithmetic expression given in advance, so that the calculated flow ratio is obtained. Water heater having a flow ratio controller for controlling the mixing ratio of the hot water and water serial mixing adjustment means. 2. The data storage section stores data of an allowable range with respect to a set flow ratio between a flow rate passing through the hot water supply heat exchanger during normal operation and a flow rate passing through the bypass passage, instead of the control mode switching time. The mode switching combustion control unit controls the combustion control only by the feedforward control based on the feedforward calorie while the flow ratio detected by the flow ratio detection unit after the start of re-hot water is out of the allowable range with respect to the set flow ratio. 2. The hot water supply apparatus according to claim 1, wherein after the detected flow rate ratio falls within the allowable range, the combustion control is performed by proportional control based on a total heat quantity of the feedforward heat quantity and the feedback heat quantity. 3. A hot water supply passage provided with a flow rate sensor and a hot water supply temperature sensor is connected to the inlet side of the hot water supply heat exchanger heated by the hot water supply combustion of the burner, and a hot water supply passage is connected to the outlet side of the hot water supply heat exchanger. The water supply passage and the hot water supply passage are separately connected to each other by a bypass passage having no passage opening / closing valve and a bypass passage having a passage opening / closing valve, respectively, so as to obtain hot water having a hot water set temperature set by a temperature setting device. Hot water supply device for controlling the combustion control and the opening and closing valve of the bypass passage,
The data of the re-watering standby time, which is the reference for performing the stabilization control of the re-hot water temperature, and the data of the control mode switching time, which is a guide for the end of the post-boiled water in the hot water supply heat exchanger after the start of the re-water supply, A data storage section storing data on the flow rate ratio between the hot water supply heat exchanger side and both bypass passage sides when the on-off valve of the bypass valve is opened and closed, and the elapsed time since the stop of hot water supply combustion A time measuring means for measuring a time, and a feed required to raise the feed water temperature to the hot water set temperature until the control mode switching time is reached when the hot water re-starting is started within the hot water standby time after the stop of the hot water combustion. Combustion control is performed only by the feedforward control based on the forward heat, and after the control mode switching time has elapsed, the total of the feedforward heat and the feedback heat is calculated. A mode switching combustion control unit that performs combustion control by proportional control based on the amount, and a flow rate ratio for taking in the temperature information of the hot water at the outlet side of the hot water heat exchanger at each sampling time and setting the hot water temperature to the hot water set temperature. A hot water supply device comprising: a flow ratio control unit that determines the open time of the on-off valve of the bypass passage using solution data given in advance and controls the open time of the on-off valve for each sampling time. 4. A mode switching combustion control unit, wherein the control based on the control mode switching time is replaced with a feedforward heat quantity while the opening time of the bypass passage controlled by the flow ratio control unit is out of a minute time range given in advance. The combustion control is performed only by the feedforward control based on the above, and after the open time falls within the short time range or becomes zero, the combustion control is performed by the proportional control based on the total heat amount of the feedforward heat amount and the feedback heat amount. 4. The hot water supply apparatus according to claim 3, wherein: