JPH04151453A - Method for leading out necessary capacity of heating means in control of hot water supply of hot-cold water combination type tap-controlled water heater - Google Patents

Abstract

PURPOSE:To conduct a control stably without hunting and to prevent shortening of the lifetime of a control element by a method wherein the temperature of tap water and the quantity of hot water supply are compared with previous values thereof and a necessary capacity is led out on the basis of stored values without updating the values thereof when they are in prescribed error ranges and with updating them when they are beyond the ranges. CONSTITUTION:On the occasion of supply of hot water, a control means 13 leads out a necessary capacity of a heating means 12 on the basis of the temperature of tap water and the quantity of hot water supply obtained by measurement and a set temperature of hot water. Prior to this leading out, it compares the temperature of tap water and the quantity of hot water supply obtained by measurement, with values stored in a storage means. When values thereof are within prescribed error ranges, the stored values are not updated and the necessary capacity is led out on the basis of the values stored theretofore. When they are beyond the error ranges, the values are updated and the necessary capacity is led out on the basis of these values. Therefore the necessary capacity led out is prevented from changing every time under the effect of a measured error, and a stable control can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for deriving the required capacity of a heating means in hot water supply control of a hot and cold instantaneous water heater.

(Prior art) In contrast to conventional instantaneous water heaters that simply heat tap water in a heat exchanger and dispense the hot water as is, in recent years, water heaters that mix the hot water from the heat exchanger with tap water have been developed. Instantaneous water heaters that can supply hot water at a desired temperature are becoming available. The former has problems such as difficulty in supplying hot water at an appropriate temperature at a small flow rate in summer due to the range of heat generated by the heating means such as a burner that heats the heat exchanger, whereas the latter like a
be able to solve problems. For example, a conventional example of a handler is disclosed in Japanese Unexamined Patent Publication No. 2-183733.

The applicant has previously proposed that hot water from a heat exchanger and tap water can be combined and mixed to supply hot water at a desired temperature in an instantaneous water heater. We proposed a hot water supply mechanism that uses a mixing valve that can freely change the flow rate ratio by moving the valve body using a thermally responsive element installed in the merging channel. (For example, refer to the specification and drawings attached to the application of Japanese Patent Application No. 1-344752.) To explain with reference to FIGS. 1 and 2, this hot water supply mechanism passes through a heat exchanger 3 provided with a burner 12. In parallel with the production route 1, a sewage route 5 is provided, which is branched on the upstream side of the heat exchanger 3 and merged downstream via a mixing valve 4. The valve body 8 is moved by a responsive element 7 to change the flow rate ratio between the water path 5 and the production path 1, and the thermally responsive element 7 is activated by an operating mechanism in accordance with the hot water setting temperature of the hot water tap temperature setting device 14. 9, and the burner 12 is controlled by the control means 13 using a temperature sensor 15 provided downstream of the heat exchanger 3 to adjust the temperature of the water on the downstream side to a predetermined temperature. It is structured as follows.

In such a configuration, the combustion of the burner 12 causes the heat exchanger 3 to
The hot water that has been heated up in the water and has flowed through the production path 1 is mixed with the tap water that has flowed through the water path 5 at the mixing valve 4, the temperature of which is lowered, and the hot water flows through the confluence path 6 and is also discharged from the hot water outlet 19. Ru. At this time, the control means 13 performs feedback control of the burner 12 based on the measured value of the temperature sensor 15, thereby controlling the heat exchanger 3.
The hot water on the downstream side of the water is adjusted to a predetermined temperature, for example, 80° C., and the thermally responsive element 7 provided in the confluence channel 6 moves the valve body 8 in response to the temperature of the hot water in the confluence channel 6. By changing the flow rate ratio between the water path 5 and the manufacturing path 1, the temperature of the hot water in the confluence path 6 can be adjusted to a value corresponding to the bias amount of the thermally responsive element 7. This bias amount can be changed by the actuating mechanism 9 in accordance with the hot water setting temperature of the hot water tap temperature setting device 14, thereby making it possible to supply hot water adjusted to the hot water tap temperature setting.

In the above-described configuration, the bias amount of the thermally responsive element 7 is such that at an average hot water output amount and tap water temperature, at a hot water tap temperature setting corresponding to the middle of the hot water tap temperature range, for example, 50°C,
The flow rate ratio mentioned above is set to be ]:],
As the hot water tap setting temperature increases, the flow rate ratio of the water production path 1 gradually increases, and conversely, as it decreases, the flow rate ratio of the water path 5 increases.

By the way, the required capacity of the burner 12 can be expressed by the following equation, for example, as the amount of heat per hour required to raise the temperature of water of number < lQ by 25° C., that is, number 1 = ] 500 kcal/hour).

As can be seen from this equation, the required capacity of the burner 12 is smaller as the hot water setting temperature is lower, the water temperature is higher in summer, etc., or the amount of hot water is smaller. Become. In this way, when the required capacity of the burner decreases to a predetermined capacity in the low capacity range, for example, No. 5 or less, the opening degree of the valve on the production path 1 side becomes very small, so This is the limit of the degree of resolution, and even a slight displacement causes a relatively large change in the flow rate on the production path 1 side, resulting in hunting and the temperature of the hot water in the merging path 6 becoming unstable. For example, if the temperature is below No. 3, there is a danger that the hot water in the heat exchanger 3 will boil due to continuous combustion, and the ON-〇FF
Control is required. If the required capacity further decreases, for example, below No. 1, the response performance limit of the heat exchanger 3 will be exceeded, and there will be a risk of boiling even with the above ON-FF control.

In order to eliminate such inconveniences, the required capacity of these burners 12 is derived at the time of hot water supply, and the control method of the heating means 12 and the mixing valve 4 is appropriately switched and controlled according to the derived required capacity. There is a need. In this case, the required capacity is derived using the above equation (1) from the water temperature measured by the temperature sensor 17, the amount of hot water measured by the flow rate measuring means 18, and the hot water setting temperature set in the hot water temperature setting device 14. It can be done by

(Problem to be solved by the invention) The measurement error of a flow rate sensor is, for example, about 7 to 8% of the flow rate.
Furthermore, the current measurement error of temperature sensors is, for example, about 1°C, and if the required capacity is derived based on the measured value without taking such measurement error into account, the derived required capacity will be There is a high possibility that the temperature will change each time due to the influence of these measurement errors, and if the control is continued as it is, it will not only result in hunting, etc., making it impossible to obtain a stable tapping temperature, but also lead to inconveniences such as a shortened lifespan of the control elements. Resulting in.

The present invention aims to solve the above problems.

(Means for Solving the Problems) The means for solving the above-mentioned problems will be explained with reference to the attached drawings.The first configuration of the method for deriving the required capacity of the heating means in hot water supply control of the present invention The heat exchanger 3 is installed in parallel with the manufacturing path 1 passing through the heat exchanger 3 provided with the heating means 12.
A water path 5 is provided which branches on the upstream side and merges through the mixing valve 4 on the downstream side, and the mixing valve 4 moves the valve body 8 by a thermally responsive element 7 provided in the merging path 6. The flow rate ratio between the water path 5 and the production path 1 is changed, and the thermally responsive element 7 is biased by the operating mechanism 9 in accordance with the hot water setting temperature of the hot water tap temperature setting device 14, and the heating means 12 is controlled by a control means 13 using a temperature sensor 15 provided on the downstream side of the heat exchanger 3 to adjust the temperature of the water on the downstream side to a predetermined temperature. In this case, the control means 13:
The required capacity of the heating means 12 is derived from the hot water set temperature, the measured tap water temperature, and the amount of hot water dispensed, and the heating means 12 and the mixing valve 4 are controlled according to this required capacity. At the same time, a means for storing the tap water temperature and hot water output amount is provided, and the tap water temperature and hot water output amount obtained by measurement are compared with these stored values, and if each is within a predetermined error range, The required ability is derived based on the previously stored values without updating the values, and if the error range is exceeded, the values are updated and the required ability is calculated based on those values. The purpose of this paper is to derive the following.

Further, in the second configuration, in the above configuration, the control means 13 derives the required capacity of the heating means 12, and when the required capacity is lower than the first set capacity in the low capacity range, When the means 12 is ON-OFF controlled in a predetermined temperature range of the high temperature range, and the required capacity is less than the second set capacity which is set lower than the first set capacity, this second set capacity is set. The gist of the present invention is to perform the ON-OFF control using the hot water outlet temperature calculated inversely with respect to the second set capacity as the hot water outlet temperature setting.

(Function) When supplying hot water, the control means 13 derives the required capacity of the heating means 12 from the above formula (1) based on the measured tap water temperature, hot water output amount, and hot water supply setting temperature, but prior to this derivation, The water temperature and amount of hot water obtained by measurement are compared with these values stored in the storage means. If these values are within a predetermined error range, the required ability is derived based on the previously stored values without updating the stored values. If the range is exceeded, the values are updated and the required ability is derived based on these values.

Therefore, the derived required capacity does not change every time due to the influence of measurement errors, and stable control can be performed. In particular, as in the second configuration, when the required capacity is lower than the first set capacity in the low capacity range, the heating means 12 is ON-OFF controlled in a predetermined temperature range in the high temperature range, and If the second setting capacity, which is set even lower than the set capacity, is not reached, the ONOF described above uses the outlet hot water temperature calculated inversely with respect to the second setting capacity as the outlet hot water set temperature.
When performing control to prevent boiling of hot water in the heat exchanger by performing F control, hunting in the operation of the mixing valve 4 in the latter control is prevented, and stable hot water output is achieved. In addition to obtaining the temperature, it is possible to prevent the life span of the control elements related to the mixing valve 4 from decreasing.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

First, FIG. 1 shows the overall configuration of an example of a hot and cold instantaneous water heater 2 to which the present invention is applied, and reference numeral 1 indicates a water gutter 2.
This is a production route passing through a heat exchanger 3, and in parallel with this production route 1, a water route 5 is provided which is branched on the upstream side of the heat exchanger 3 and merged via a mixing valve 4 on the downstream side. . Mixing valve 4
As shown in FIG.
In addition to changing the flow rate ratio, an actuation mechanism 9 such as an electric actuation mechanism that biases the thermally responsive element 7 is provided. The thermally responsive element 7 is configured to expand and contract thermally by enclosing wax, for example.
The direction is to increase the amount of water. This thermally responsive element 7 has a configuration in which the amount of bias is adjusted by an actuating body] 1 via a bias spring 10, and as described above, this actuating body 11 is actuated by an actuating mechanism 9 such as an electric actuating mechanism. It is configured to move in the vertical direction.

In the above configuration, Fig. 2(a) shows a state in which the amount of hot water in the manufacturing path 1 is large, and in this state, the wax expands and the thermally responsive element as shown in Fig. 2(b). 7 thermally expands, the valve body 8 is moved downward to reduce the amount of hot water in the production path 1, and at the same time increases the amount of water in the water path 5, causing the temperature of the hot water in the confluence path 6 to drop; When the temperature decreases too much and the thermally responsive element 7 contracts, the valve body 8 is moved upward to reduce the amount of water in the water path 5, and at the same time, the amount of hot water in the production path 1 is increased and the amount of hot water in the merging path 6 is increased.
By increasing the temperature of the hot water inside, the temperature of the hot water flowing through the confluence channel 6 can be controlled in this way. When the thermally responsive element 7 is biased downward by the operating mechanism 9, the set hot water temperature can be lowered, and conversely, when the thermally responsive element 7 is biased upward, the set hot water temperature can be increased.

Reference numeral 12 denotes a heating means for heating the heat exchanger 3. In the illustrated example, the heating means 12 is a burner, but an electric heater or the like may be used in addition to the burner 12. Reference numeral 13 denotes a control means, and 14 denotes a hot water temperature setting device. Based on the water temperature from the sensor 15, the burner 1 is controlled so that the water temperature on the downstream side of the heat exchanger 3 reaches a predetermined target temperature.
If the combustion amount in step 2 is feedback-controlled, or if the required capacity is lower than the first set capacity in the low capacity range described later,
The burner] 2 is turned on and off in a predetermined temperature range of high temperature range.
Flow rate measuring means 1 for controlling and measuring the flow rate in the manufacturing path l
6 and a temperature sensor that measures the temperature of the tap water] the measured value of 7,
Feedforward control is performed from the target temperature, and the actuation mechanism 9 is actuated to set the bias to the thermally responsive element 7. In the above embodiment, the flow fi measuring means is provided with a flow rate measuring means 8 capable of measuring the total flow rate and a flow rate measuring means 16 capable of measuring the flow rate of the manufacturing path 1. Manufacturing route 1
The flow rate can also be calculated from the total flow rate measured by the flow rate measuring means 18, the tap water temperature, the hot water outlet temperature setting, and the hot water temperature on the downstream side of the heat exchanger. 16 can be omitted.

A specific example of the method for deriving the required capacity of the heating means of the present invention in the above configuration is shown in FIG. This will be explained with reference to the flowchart shown in FIG.

As shown in FIG. 3, after starting the control, in step S1, it is determined from the measured value of the flow rate measuring means 18 whether the total flow rate, that is, the amount of hot water supplied, satisfies a predetermined amount, in this case 3Q/min. do. This predetermined amount is the amount set as the minimum flow rate that can be used by the user, and when the flow rate is less than this flow rate, combustion is stopped (step So). If the amount of hot water dispensed is equal to or greater than the predetermined amount, control is branched in the next step S2 based on the hot water set temperature of the hot water temperature setter 14. That is, if the hot water setting temperature is 65° C. or higher, the process moves to step S3, and if it is below that temperature, the process moves to step S5, which corresponds to the derivation process of the present invention. In this embodiment, when the boundary temperature is 65°C, step S
3, however, which step to branch to at a boundary value such as temperature can be set as appropriate, including the branch judgment step described later.

If the process moves to step S3, that is, the hot water setting temperature is 65.
℃ or higher, the control means 13 uses the operating mechanism 9 to move the valve body 8 via the thermally responsive element 7 to fully open the hot water path l side and close the water path 5 side, and closes the mixing valve 4. The operation is stopped. Next, in step S4, the control means 13 performs feedforward control using the measured values of the flow rate measuring means 16 for measuring the flow rate of the hot water path 1 and the temperature sensor 17 for measuring the temperature of the tap water, and the control means 13 for controlling the heat exchanger 3. The combustion amount of the burner 12 is controlled by feedback control using the measured value of the temperature sensor 15 on the downstream side of the burner 12 with the hot water outlet temperature set as a target value. By performing such control, the temperature of the hot water on the downstream side of the heat exchanger 3, that is, the temperature of the hot water flowing into the hot water path 1 side of the mixing valve 4, passing through the merging path 6, and exiting from the hot water outlet 19, can be controlled. The hot water tap temperature can be adjusted to a desired temperature. In this type of control, since the mixing valve 4 is in a stopped state, hunting essentially does not occur, and the burner 12 is also controlled in a combustion range that is easy to control, so it is easy to control. Hunting is also less likely to occur.

In addition, in the control of the burner 12 described above, it is also possible to omit the feedforward control. Moreover, the above steps s3 and S4 can be performed simultaneously or in the reverse order.

Step S5, which is a transition from the determination in step s2 described above;
That is, step S5 corresponding to the control process in the present invention consists of the following steps 820 to 326. First, in step s20, the amount of hot water currently measured by the flow rate measuring means 18 is compared with the previous amount of hot water stored in the storage means, and the rate of change is derived. Next, the derived rate of change is compared with a set value in step S21. Therefore, if the absolute value of the rate of change derived in this way is, for example, 7°7
% or more, the process moves to step S22, where the stored content of the storage means is updated to the value of the currently measured hot water output amount, and then the process moves to step S23. On the other hand, if the absolute value of the rate of change is not 7.7% or more, the contents of the storage means are not updated and the process proceeds to step S23 with the previous stored contents unchanged.

In step S23, the water temperature measured this time by the temperature sensor 17 is compared with the previous water temperature stored in the storage means, and the amount of change is derived.Then, in step S24, the amount of change is derived. Compare the amount of change with the set value. However, if the absolute value of the amount of change derived in this way is, for example, 1'C or more, the process moves to step S25,
The stored contents of the storage means are updated to the currently measured water temperature value, and then the process moves to step S26. On the other hand, if the absolute value of the amount of change is not 1° C. or more, the contents of the storage means are not updated and the process proceeds to step S26 with the previous stored contents unchanged.

In this way, in step S26, the required capacity of the heating means 12 is calculated based on the above-mentioned equation (1) from the hot water amount and tap water temperature stored in the storage means, and the hot water setting temperature set in the hot water temperature setting device 14. Perform the derivation. The control process of the present invention consisting of the above steps 520-'S26 compares the measured clean water temperature and hot water output amount with these values stored in the storage means, and determines whether these values are respectively predetermined. If it is within the error range, the required ability is derived based on the previously stored value without updating the value, and if it exceeds the error range, the value is updated and those Since the required ability is derived based on the value, the derived required ability does not change each time due to measurement error, and stable control can be performed. Note that, as described above, the error range can be appropriately determined by the rate of change, amount of change, etc.

Next, in step S6, the derived required ability is
Branching of control is performed by comparing with a second preset setting capacity. This second setting ability is set lower than the first setting ability described later, and this second setting ability corresponds to the limit of the response performance of the heat exchanger 3 in the feedback control.

In this embodiment, this second setting ability is set to No. 1. If the required capacity derived as described above is larger than No. 1, in the next step S7, the thermally responsive element 7 is biased by the actuating mechanism 9, and if the number is less than 1, the process branches to step S17.

If the process branches to step S7, then step S8
In this step, the required capacity derived above is again compared with the set capacity and control is branched. The setting ability to be compared is the first setting ability, which is No. 3 in this embodiment, which is greater than the second setting ability described above. This first setting capability, ie, No. 3, corresponds to the limit at which the temperature of the hot water on the downstream side of the heat exchanger 3 can be stably controlled to the set temperature by the feedback control or feedforward control. However, if the above-mentioned required ability is lower than No. 3, step S]9
If the value is high, the process moves to step S9. In step S19, the burner 12 is ON-OFF controlled within a predetermined temperature range of the high temperature range. That is, the control means 13
When the temperature of the hot water on the downstream side of the heat exchanger 3 reaches 85°C or higher, combustion in the burner 12 is stopped, and when the hot water temperature decreases to 75°C or lower due to the stoppage of combustion, combustion is stopped. Performs restart ON-OFF control. By performing such control, even if the required capacity is below the limit for stably controlling the water temperature downstream of the heat exchanger 3 to the set temperature, boiling of the water in the heat exchanger 3 can be prevented. By operating the mixing valve 4, hot water can be discharged at the temperature set in the hot water temperature setting device 14.

On the other hand, when the process moves from step S6 to step S17, that is, when the required ability derived as described above is less than the second setting ability, that is, No. 1, this step S17
In this step, the second setting capacity, that is, the outlet temperature calculated inversely to No. 1 is derived.

That is, the tapping temperature is derived using the following equation, which is a modification of equation (1).

Amount of hot water dispensed Next, in step S18, the thermally responsive element 7 is biased by the actuating mechanism 9 in accordance with the dispensed hot water temperature derived as described above, and in this state, the step S18 is performed.
19, the above-mentioned ON-OFF control is performed. By doing this, the burner is maintained in the No. 1 operation, and therefore, the above-mentioned ON-OFF control can prevent the hot water in the heat exchanger 3 from boiling, and the hot water temperature rises slightly from the initially set temperature. However, it is possible to prevent the temperature from decreasing due to combustion termination.

On the other hand, when the process moves from step S8 to step S9, in this step S9, the above-mentioned derived required capacity is again compared with the set capacity and control is branched. The setting ability to be compared is a third setting ability, which is larger than the first setting ability described above, and is No. 5 in the embodiment. This third setting capacity corresponds to the lowest capacity that can prevent the occurrence of hunting due to the mixing valve 4 operating in a low capacity range with the valve opening on the hot water path 1 side close to closed.

If the derived required ability is greater than No. 5, the process moves to step S13, and if it is lower, the process proceeds to step S13.
Move to O. In the former case, it is determined in step S13 whether or not No. 5 and below have been stored in the appropriate storage means in the control means 13, and if not stored, the process proceeds to step S16. If it has been transferred and stored, the process moves to the next step S14, and in this step S14, the above-mentioned derived required ability is further determined. That is, in step 314, it is determined whether the current capacity is greater than the third setting capacity, larger or smaller than No. 6, and if it is larger, it is determined that the control hysteresis has been exceeded and the process moves to the next step S15. , this step S15
After erasing the memory of No. 5 and below, the process moves to the next step S16. In this way, steps S13, S
14 and 315 constitute control hysteresis to prevent hunting.

Therefore, in step S16, the target value of the water temperature on the downstream side of the heat exchanger 3 is set to a predetermined maximum temperature, for example, 80°C.
The burner 12 is controlled as feedback control and feedforward control.

On the other hand, in step SIO, the hot water temperature setting device 14
If the set hot water outlet temperature is a predetermined temperature, for example, 50° C. or higher, the process moves to step S12, and if it is 50° C. or lower, the process moves to step Sll. Therefore, in step S12, the heating means 12 is feedback-controlled by using the temperature obtained by adding a predetermined temperature range, for example, +15° C., to the hot water set point temperature as the target value of the hot water temperature on the downstream side of the heat exchanger 3. , feedforward control. For example, when the hot water tap temperature setting is 60°C, the target value is 75°C. Note that the temperature of the water on the downstream side of the heat exchanger 3 is limited for safety reasons, so even though the target value is derived in this way, the maximum temperature is the same as the maximum temperature in step S16 above. need to be limited to.

On the other hand, when the process moves to step Sll, that is, when the hot water outlet temperature setting is 50°C or lower, the burner 12 is set to a certain predetermined temperature, for example, 60°C, as the target value of the hot water temperature on the downstream side of the heat exchanger 3. Feedback control, feedforward control.

The hot water heated to the predetermined temperature in the heat exchanger 3 by combustion in the burner 12 under the above control and flowing through the production path 1 and reaching the mixing valve 4 is heated at the mixing valve 4. The hot water mixes with the tap water that has flowed through the water path 5 to lower its temperature, flows through the confluence path 6, and is tapped out from the hot water outlet 19. At this time, the thermally responsive element 7 provided in the merging channel 6 moves the valve body 8 in response to the temperature of the water in the merging channel 6, so that the flow rate ratio between the water channel 5 and the manufacturing channel 1 changes. , thus the water temperature in the confluence channel 6,
It can be adjusted to a value depending on the amount of bias of the thermally responsive element 7. In this kind of control, the hot water heated by the burner 12 in the heat exchanger 3 can be cooled with tap water and then discharged from the hot water outlet 19, so that when the minimum combustion amount of the burner 12 is relatively large, It is also possible to supply hot water at a low temperature with a small flow rate. In addition, during intermittent use at relatively short time intervals, hot water in the production path 1 may be contaminated with hot water (overshoot) due to after-boiling in the heat exchanger 3 or cold water due to ignition delay of the burner 12. Even if there is an undershoot, etc., it will not be transmitted to the hot water in the confluence channel 6. In addition, the heating means 12
In addition to the number of symbols, an appropriate scale can be used for the required ability.

(Effects of the Invention) As described above, the present invention uses a mixing valve that can freely change the flow rate of hot water and tap water from a heat exchanger by moving a valve body using a thermally responsive element provided in a merging channel. In an instant hot water heater that can supply hot water at a desired temperature by mixing the hot water at the desired temperature, the required capacity of these heating means is derived at the time of hot water supply, and the heating means and the hot water are adjusted according to the derived required capacity. In addition to controlling the mixing valve by appropriately switching the control method, deriving this required capacity is based on the measured water temperature and hot water output amount.
compared with these previous values stored in the storage means,
If each of these values is within a predetermined error range, the required ability is derived based on the previously stored value without updating the value, and if it exceeds the error range, the value is By updating the above values and deriving the required capacity based on those values, the problem that the derived required capacity changes every time due to the influence of measurement error does not occur, and therefore, there is no hunting due to this. This has the effect that stable control can be performed, a stable tapping temperature can be obtained, and a reduction in the life of the control element can be prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention, and FIGS. 2(a) and 2(b) are explanatory cross-sectional views showing the configuration and operation of the embodiment of a mixing valve. Further, FIG. 3 is a flow chart showing a specific example of the entire control including the method of the present invention, and FIG. 4 is a flow chart showing the method of the present invention in detail. Code l... Hot water route, 2... Water heater, 3... Heat exchanger, 4... Mixing valve, 5... Water route, 6... Merging path, 7... Heat Response element, 8... Valve body, 9... Actuation mechanism, 10... Bias spring, 11... Actuation body, 12
...Heating means (burner) 13, control means, 14...
Hot water outlet temperature setting device, 15... Temperature sensor, 16... Flow rate measuring means, 17... Temperature sensor, 18... Total flow rate measuring means, 19... Tap water outlet, 20... Return spring.

Claims (4)

[Claims] (1) In parallel with the hot water path passing through the heat exchanger provided with the heating means, provide a water path that branches on the upstream side of the heat exchanger and joins through the mixing valve on the downstream side, and the mixing valve The valve body is moved by a thermally responsive element provided in the merging path to change the flow rate ratio between the water path and the hot water path, and the thermally responsive element is operated in accordance with the hot water setting temperature of the hot water tap temperature setting device. The heating means is biased by a mechanism, and the heating means is controlled by a control means using a temperature sensor provided downstream of the heat exchanger to adjust the temperature of the water on the downstream side to a predetermined temperature. In the hot water mixing type instantaneous water heater, the control means derives the required capacity of the heating means from the hot water setting temperature, the measured tap water temperature and the hot water output amount, and adjusts the required capacity according to this required capacity. In addition to controlling the heating means and the mixing valve, the heating means and the mixing valve are also provided with storage means for storing the water temperature and the amount of hot water output, so that the water temperature and the amount of hot water obtained by measurement can be stored as these stored values. If it is within a predetermined error range, the required ability is derived based on the previously stored value without updating the value, and if it exceeds the error range, the value is A method for deriving the required capacity of a heating means in hot water supply control of a hot water mixing type instantaneous water heater, characterized in that the required capacity is derived based on these values. (2) The control means according to claim 1 derives the required capacity of the heating means, and when the required capacity is lower than the first set capacity of the low capacity range, the control means operates the heating means within a predetermined temperature range of the high temperature range. When the required capacity is less than the second setting capacity, which is set lower than the first setting capacity, the second setting capacity is calculated backwards. The above ON-OF with the hot water temperature as the hot water set temperature
Method for deriving the required capacity of a heating means in hot water supply control of a hot water mixing type instantaneous water heater characterized by performing F control (3) A method for deriving the required capacity of a heating means in hot water supply control of a hot and cold instantaneous water heater, characterized in that the heating means of claim 1 is a burner. (4) The heat-responsive element according to claim 1 is a heating means in hot water supply control of a hot water mixing type instantaneous water heater, characterized in that the thermally responsive element has a built-in wax and is configured to expand and contract according to the surrounding temperature. How to derive the required ability of