JP2886319B2 - Derivation method of required capacity of heating means in hot water supply control of mixed water heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for deriving the required capacity of a heating means in hot water supply control of a mixed hot water heater.

(Prior art) Compared to a conventional ordinary instantaneous water heater, in which tap water is simply heated in a heat exchanger and the tap water is supplied as it is, water from the heat exchanger and tap water have recently been mixed. Instantaneous water heaters capable of supplying hot water at a desired temperature are being provided. The former has the problem that it is difficult to supply hot water with a small flow rate in summer due to the range of heat generated by heating means such as a burner for heating the heat exchanger, whereas the latter has this problem. Such problems can be solved. For example, the latter conventional example is disclosed in JP-A-2-183733.

The applicant of the present invention has previously described the mixing of hot water and clean water in such an instantaneous water heater that can mix hot water from the heat exchanger and supply hot water at a desired temperature. A hot water supply mechanism in which the valve body is moved by a thermally responsive element provided in the combined flow path and a mixing valve capable of changing a flow rate ratio is proposed. (For example, refer to the specification and drawings attached to the application of Japanese Patent Application No. 1-344752.) Referring 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 hot water path 1, there is provided a water path 5 which branches on the upstream side of the heat exchanger 3 and joins on the downstream side via a mixing valve 4. The valve element 8 is moved by the responsive element 7 to change the flow rate ratio between the water path 5 and the hot water path 1, and the thermally responsive element 7 is set to a tapping temperature setting device.
The control unit 13 controls the burner 12 using a temperature sensor 15 provided on the downstream side of the heat exchanger 3. The downstream hot water temperature is adjusted to a predetermined temperature.

In such a configuration, the heat exchanger 3
The hot water flowing through the hot water path 1 is mixed with the clean water flowing through the water path 5 in the mixing valve 4 to lower the temperature, flows through the combined flow path 6 and is discharged from the tap 19. You. At this time, the control means 13 adjusts the temperature of the hot water downstream of the heat exchanger 3 to a predetermined temperature, for example, 80 ° C. by performing feedback control of the burner 12 based on the measurement value of the temperature sensor 15. The heat responsive element 7 provided therein moves the valve element 8 in response to the temperature of the hot water in the merging flow path 6 to change the flow rate ratio between the water path 5 and the hot water path 1, thus The temperature of the hot water can be adjusted to a value corresponding to the amount of bias of the thermoresponsive element 7. The bias amount can be changed by the operating mechanism 9 in accordance with the tapping temperature set by the tapping temperature setter 14, and thus hot water adjusted to the tapping set temperature can be supplied.

In the above-described configuration, the bias amount of the thermally responsive element 7 is such that, at the average tap water amount and the tap water temperature, at the tap water set temperature corresponding to the middle of the tap water temperature range, for example, at 50 ° C.
The above-mentioned flow rate ratio is set to 1: 1. The flow rate ratio of the hot water path 1 gradually increases as the tapping set temperature increases, and the flow rate ratio of the water path 5 increases when the tapping temperature decreases. Incidentally, the required capacity of the burner 12 is, for example, the number (1
The amount of heat per hour required to raise the temperature of water by 25 ° C,
That is, it can be expressed by the following equation as No. 1 = 1500 kcal / hour).

As can be seen from this equation, the required capacity of the burner 12 becomes smaller as the set hot water temperature is lower, the water temperature is higher or the amount of hot water is smaller in summer or the like, and the flow rate on the hot water path 1 side is also smaller. Become. In this way, the required capacity of the burner is reduced, and if the required capacity in the low capacity area, for example, the required capacity becomes 5 or less, the opening degree of the valve on the hot water path 1 side becomes very small. The limit of the resolution of the degree is reached, and even a small displacement causes a relatively large change in the flow rate on the hot water path 1 side, thus causing hunting and making the hot water temperature in the combined flow path 6 unstable. For example, when the temperature is 3 or less, there is a risk that the hot water in the heat exchanger 3 will boil in continuous combustion, and ON-OFF control is required. When the required capacity further decreases, for example, when the required capacity is equal to or less than 1, the response performance of the heat exchanger 3 exceeds the limit, and there is a risk of boiling even in the above ON-OFF control.

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

(Problems to be Solved by the Invention) At present, the measurement error of the flow sensor is, for example, about 7 to 8% of the flow rate, and the measurement error of the temperature sensor is, for example, about 1 ° C. Without taking into account, if the required capacity is derived based on the measurement value as it is, there is a large possibility that the derived required capacity will be affected each time by these measurement errors and will change, and if control is performed as it is,
Hunting and the like cause not only a stable tapping temperature, but also inconvenience such as a shortened life of the control element.

An object of the present invention is to solve the above problems.

(Means for Solving the Problems) Means for solving the above problems will be described with reference to the accompanying drawings. First, a first configuration of a method for deriving a required capacity of a heating means in hot water supply control of the present invention. Is connected in parallel with the hot water path 1 passing through the heat exchanger 3 provided with the heating means 12.
A water path 5 is provided for branching on the upstream side and merging via a mixing valve 4 on the downstream side, and the mixing valve 4 is moved by a heat-responsive element 7 provided in a merging path 6 to move a valve body 8. The flow rate ratio between the water path 5 and the hot water path 1 is changed, and the heat responsive element 7 is biased by the operating mechanism 9 in accordance with the tapping temperature set by the tapping temperature setter 14, and the heating means 12 is controlled by control means 13 using a temperature sensor 15 provided on the downstream side of the heat exchanger 3,
In the hot water mixing type instantaneous water heater configured to adjust the temperature of the downstream hot water to a predetermined temperature, the control means 13 heats the hot water from the set hot water temperature and the clean water temperature and the hot water amount obtained by the measurement. means
The required capacity of 12 is derived, and the heating means 12 and the mixing valve 4 are controlled in accordance with the required capacity.
Providing a storage means for the tap water temperature and the tap water amount, comparing the tap water temperature and tap water amount obtained by the measurement with these stored values, and when each falls within a predetermined error range, Without updating the value, the required capacity is derived based on the value stored so far, and when the error exceeds the error range, the value is updated, and the required capacity is updated based on those values. The point is to derive.

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 area, the heating means Means 12 is ON-OFF controlled in a predetermined temperature range of a high temperature range, and when the required capacity is less than a second set capacity which is set lower than the first set capacity, the second set capacity is set. The gist is to perform the ON-OFF control using the tapping temperature calculated backward with respect to the setting capability of the above as the tapping set temperature.

(Operation) At the time of hot water supply, the control means 13 derives the required capacity of the heating means 12 from the above equation (1) based on the tap water temperature, the tap water amount and the tap water set temperature obtained by the measurement. The water temperature and tap water amount obtained by the measurement are compared with these values stored in the storage means.
If these values are within predetermined error ranges, the stored values are not updated, and the required capacity is derived based on the values stored so far. When the value exceeds the range, the values are updated, and the required capacity is derived based on those values. Therefore, the derived required capacity does not change every time due to the measurement error, 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 area, the heating means 12 is ON-OFF controlled in a predetermined temperature range in the high temperature area, and If the second set capacity which is lower than the set capacity is less than the second set capacity, the above-mentioned ON-OFF control is performed by using the tap water temperature calculated backward with respect to the second set capacity as the tap water set temperature. In the case where control is performed so as to prevent boiling of hot water in the heat exchanger, hunting is prevented from occurring in the operation of the mixing valve 4 in the latter control, and a stable tapping temperature is obtained. It is possible to prevent the life of the control element related to the mixing valve 4 from being shortened.

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

First, FIG. 1 shows an entire configuration of an example of a hot water / mixing type instantaneous water heater 2 to which the present invention is applied, and reference numeral 1 denotes a hot water path passing through a heat exchanger 3 of the water heater 2. A water path 5 is provided in parallel with the hot water path 1, which branches off on the upstream side of the heat exchanger 3 and joins via a mixing valve 4 on the downstream side. As shown in FIG. 2, the mixing valve 4 has a structure in which a valve element 8 is moved by a heat responsive element 7 provided in a joining flow path 6 to change a flow rate ratio between the water path 5 and the hot water path 1. An operating mechanism 9 such as an electric operating mechanism for biasing the thermal response element 7
Is provided. The thermally responsive element 7 is configured to thermally expand and contract by enclosing wax, for example.
Is the direction in which the amount of hot water in the hot water path 1 is reduced and the amount of water in the water path 5 is increased. This thermoresponsive element 7
Is configured to adjust a bias amount by an operating body 11 via a bias spring 10, and the operating body 11 is operated by an operating mechanism 9 such as an electric operating mechanism and moved in the vertical direction in the figure as described above. And In the above configuration, FIG. 2 (a) shows a state where the amount of hot water in the hot water path 1 is large. In this state, the wax expands and the heat responsive element as shown in FIG. 2 (b). When the thermal expansion 7 occurs, the valve element 8 is moved downward to reduce the amount of hot water in the hot water path 1 and to increase the amount of water in the water path 5 so that the temperature of the hot water in the merged channel 6 decreases. When the temperature of the heat responsive element 7 is reduced too much and the thermal responsive element 7 contracts, the valve element 8 is moved upward to reduce the amount of water in the water path 5 and increase the amount of water in the hot water path 1 to increase the temperature of the hot water in the junction flow path 6. Thus, the temperature of the hot water flowing through the joining channel 6 can be controlled. Then, the thermoresponsive element 7 is operated by the operating mechanism 9.
Is biased downward, the set hot water temperature can be lowered. Conversely, if it is biased upward, the set hot water temperature can be raised.

Reference numeral 12 denotes a heating unit for heating the heat exchanger 3. In the illustrated example, the heating unit 12 is a burner. However, an electric heater or the like may be used instead of the burner 12. Reference numeral 13 denotes control means, and reference numeral 14 denotes a hot water temperature setting device. The control means 13 controls the burner 12 by setting the hot water temperature of the hot water temperature setting device 14 and the temperature of a thermistor or the like provided downstream of the heat exchanger 3. Based on the temperature of the hot water from the sensor 15, the amount of combustion of the burner 12 is feedback-controlled so that the temperature of the hot water downstream of the heat exchanger 3 becomes a predetermined target temperature. If the burner 12 is lower than the first set ability,
ON-OFF control in a predetermined temperature range of a high temperature range, and a feed rate which is obtained from a measured value of a flow rate measuring means 16 for measuring a flow rate of the hot water path 1 and a temperature sensor 17 for measuring a temperature of clean water, and the target temperature. In addition to the forward control, the operation mechanism 9 is operated to set the above-described bias to the thermal response element 7. In the above embodiment, the flow rate measuring means is a flow rate measuring means capable of measuring the total flow rate.
18 and flow rate measuring means 16 capable of measuring the flow rate of the hot water path 1. The flow rate of the hot water path 1 is determined by the total flow rate measured by the flow rate measuring means 18, the tap water temperature, the tap water setting temperature, and the heat flow. The flow rate can be calculated from the temperature of the hot water downstream of the exchanger. Therefore, the flow rate measuring means 16 for measuring the flow rate of the hot water path 1 can be omitted.

A specific example of the derivation direction of the required capacity of the heating means of the present invention in the above configuration is shown in FIG. 3 showing the entire control process including the derivation process of the present invention, and the derivation process of the present invention is shown in detail. This will be described with reference to the flowchart of FIG.

As shown in FIG. 3, first, after the control is started, in step S1, it is determined from the measured value of the flow rate measuring means 18 whether or not the total flow rate, that is, the tapping amount is a predetermined amount, in this case, 3 l / min. I do. This predetermined amount is an amount set as the minimum flow rate that can be used by the user. If the flow rate is less than the minimum flow rate, the combustion is stopped (step S0). If the amount of hot water is equal to or greater than the predetermined amount, control branches based on the hot water set temperature of hot water temperature setter 14 in the next step S2. That is, when the hot water setting temperature is 65 ° C. or higher, the process proceeds to step S3,
If the temperature is equal to or lower than the temperature, the process proceeds to step S5 corresponding to the derivation process of the present invention. Note that, in this embodiment, when the boundary temperature is 65 ° C., the process shifts to step S3. It can be set appropriately, including a branch determination step described later.

When the process proceeds to step S3, that is, the hot water setting temperature is 65 ° C.
In the above case, the control means 13 moves the valve body 8 via the thermal response element 7 by the operating mechanism 9 to fully open the hot water path 1 side and close the water path 5 side, and to operate the mixing valve 4. Is stopped. Next, in step S4, the control means 13
Feed forward 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 clean water, and utilizing the measured values of the temperature sensor 15 on the downstream side of the heat exchanger 3 With this feedback control, the combustion amount of the burner 12 is controlled with the tapping set temperature as a target value.
By performing such control, the temperature of the hot water downstream of the heat exchanger 3, that is, the temperature of the hot water that flows into the hot water path 1 of the mixing valve 4 and flows out of the hot water outlet 19 through the merging flow path 6 as it is, It can be adjusted to the desired tapping set temperature. In such control, since the operation of the mixing valve 4 is stopped, the hunting does not occur essentially, and
Since 12 is also controlled in a combustion zone where control is easy, control is easy and hunting is unlikely to occur. In the control of the burner 12, the feedforward control can be omitted. Steps S3 and S4 can be performed simultaneously or in the reverse order.

Step S5, which has shifted from the above-described determination of step S2, that is, step S5 corresponding to the control process in the present invention, includes the following steps S20 to S26. First, in step S20, the amount of hot water measured this time 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 change rate is used in step S21.
And compare with the set value. If the absolute value of the rate of change thus derived is, for example, 7.7% or more, the process proceeds to step S22, and the storage content of the storage means is updated to the value of the hot water amount measured this time. Move to On the other hand, if the absolute value of the change rate is not equal to or more than 7.7%, the content of the storage means is not updated, and the process proceeds to step S23 with the previously stored content.

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. Next, in step S24, the derived change amount is compared with a set value. If the absolute value of the amount of change thus derived is, for example, 1 ° C. or more, the flow shifts to step S25 to update the content stored in the storage means to the fresh water temperature value measured this time, and then to step S26 Move to On the other hand, when the absolute value of the variation is not 1 ° C. or more, the content of the storage unit is not updated,
The process moves to step S26 with the previous stored contents.

Thus, in step S26, the required capacity of the heating means 12 is determined based on the above formula (1) based on the tap water amount and tap water temperature stored in the storage means and the tap water set temperature set in the tap water temperature setting unit 14. Perform derivation. Step S2 above
The control process of the present invention consisting of 0 to S26 compares the clean water temperature and the tap water amount obtained by the measurement with these values stored in the storage means, and these values are respectively within a predetermined error range. In some cases, without updating the value, the required capacity is derived based on the value stored so far, and when the error is exceeded, the value is updated, and based on those values, Since the required capacity is derived, the derived required capacity does not change every time due to a measurement error, and stable control can be performed. Note that, as described above, the error range can be appropriately grasped such as a change rate and a change amount.

Next, in step S6, the derived required capacity is
The control is branched in comparison with the second set capability set in advance. The second setting capability is set lower than a first setting capability described later, and the second setting capability corresponds to the limit of the response performance of the heat exchanger 3 in the feedback control. In this embodiment, the second setting capability is 1
No. is set. However, when the required capacity derived as described above is larger than No. 1, in the next step S7, the heat responsive element is directly corresponded to the tapping temperature set in the tapping temperature setter 14. 7 is biased by the operating mechanism 9, and if less than 1, the step S1
Branch to 7.

If the process branches to step S7, then, in step S8, the above-mentioned derived required capacity is again compared with the set capacity, and control is branched. The setting capability to be compared is the first setting capability which is larger than the above-described second setting capability, and is the third setting capability in this embodiment. The first setting capability, that is, No. 3, corresponds to a limit at which the temperature of the hot water downstream of the heat exchanger 3 can be stably controlled to the set temperature by the feedback control or the feedforward control. If the required capacity is lower than No. 3, the process proceeds to step S19, and if the required capacity is higher, the process proceeds to step S9. Steps
In S19, the burner 12 is turned on in a predetermined high temperature range.
-OFF control. In other words, the control means 13 stops the combustion of the burner 12 when the temperature of the hot water downstream of the heat exchanger 3 becomes 85 ° C. or higher, and reduces the temperature of the hot water by stopping the combustion.
When the temperature drops below ℃, ON-OFF control to restart combustion is performed. By performing such control, it is possible to prevent boiling of the hot water in the heat exchanger 3 even when the required capacity is below the limit at which the temperature of the hot water downstream of the heat exchanger 3 can be stably controlled to the set temperature. The operation of the mixing valve 4 allows the tapping at the temperature set in the tapping temperature setting unit 14.

On the other hand, when shifting from step S6 to step S17,
That is, if the required capacity derived as described above is less than the second set capacity, that is, No. 1, in this step S17, the tapping temperature back calculated for the second set capacity, that is, No. 1 Is derived. That is, the tapping temperature is derived by the following equation obtained by modifying the equation (1).

Next, in step S18, the thermoresponsive element 7 is moved to the operating mechanism 9 in accordance with the tapping temperature as described above.
And in this state,
The process proceeds to S19 to perform the above-described ON-OFF control. By doing so, the burner maintains the operation of No. 1 and therefore the above ON
By the -OFF control, the boiling of the hot water in the heat exchanger 3 can be prevented, and the temperature of the hot water slightly increases from the initially set temperature, but the temperature can be prevented from lowering due to the stop of the combustion.

On the other hand, when the process proceeds from step S8 to step S9, in step S9, the above-mentioned derived required capacity is again compared with the set capacity, and the control branches. The setting capability to be compared is the third setting capability which is even larger than the above-described first setting capability, which is No. 5 in the embodiment. The third setting capability corresponds to the minimum capability capable of preventing the occurrence of hunting due to the fact that the mixing valve 4 operates in the low-capacity region when the valve opening on the hot water path 1 side is close to closed. .

Thus, if the derived required capacity is larger than No. 5, the process proceeds to step S13, and if it is lower, the process proceeds to step S10. In the former case, it is determined in step S13 whether or not the number 5 or less has been stored in the appropriate storage means in the control means 13, and if not, the flow proceeds to step S16. If you have migrated and remembered,
The process proceeds to the next step S14, and in this step S14, the above-mentioned derived required capacity is further determined. That is, step S1
In step 4, it is determined whether the current capacity is larger than the third set capacity or larger or smaller than No. 6, and if it is larger, it is determined that the control hysteresis has been exceeded and the next step S1 is performed.
The process proceeds to step S5, and in this step S15, after erasing the data of No. 5 and thereafter, the process proceeds to the next step S16. Thus, steps S13, S14 and S15 form a hysteresis of the control to prevent hunting.

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

On the other hand, in step S10, the hot water setting temperature of the hot water temperature setting device 14 is determined, and the hot water setting temperature is the predetermined temperature,
For example, when the temperature is equal to or higher than 50 ° C., the process proceeds to step S12. When the temperature is equal to or lower than 50 ° C., the process proceeds to step S11. Thus, in step S12, the heating means 12 is subjected to feedback control by using a temperature obtained by adding a predetermined temperature range, for example, + 15 ° C., to the hot water setting temperature as a target value of the hot water temperature on the downstream side of the heat exchanger 3. , Feed forward control. For example, when the tapping set temperature is 60 ° C, the target value is 75 ° C. Since the temperature of the hot water downstream of the heat exchanger 3 is limited for safety reasons, the maximum temperature is the maximum temperature in step S16 despite the derivation of the target value in this manner. Need to be restricted to

On the other hand, when the process proceeds to step S11, that is, when the tapping set temperature is 50 ° C. or less, a predetermined temperature, for example, 60 ° C.
The burner 12 is subjected to feedback control and feedforward control with the temperature set to the target value of the hot water temperature downstream of the heat exchanger 3.

The hot water which has been heated to the above-mentioned predetermined temperature in the heat exchanger 3 by the combustion of the burner 12 under the above control and which has flowed through the hot water path 1 to reach the mixing valve 4 is supplied to the mixing valve 4. The water is mixed with the clean water flowing through the water path 5 to lower the temperature, flows through the merging path 6 and is discharged from the tap hole 19. At this time,
The heat responsive element 7 provided therein moves the valve element 8 in response to the temperature of the hot water in the merging flow path 6, so that the water path 5 and the hot water path 1 are moved.
Of the hot water in the joining flow path 6 can be adjusted to a value corresponding to the bias amount of the thermoresponsive element 7 in this manner. In such control, the heat exchanger 3
Since the hot water whose temperature has been raised by 12 can be cooled with tap water and discharged from the tap hole 19, even when the minimum combustion amount of the burner 12 is relatively large, low-temperature hot water can be supplied at a small flow rate. During intermittent use at relatively short time intervals, the hot water in the hot water path 1 may contain high-temperature hot water (overshoot) due to post-boiling in the heat exchanger 3 or cold water due to a delay in ignition of the burner 12. Even if there is (undershoot) or the like, it is not transmitted to the hot water in the merged channel 6. The required capacity of the heating means 12 can use an appropriate scale in addition to the number.

(Effect of the Invention) As described above, the present invention uses hot water and clean water from a heat exchanger,
A hot-water mixing type instantaneous water heater in which a valve element is moved by a heat-responsive element provided in a joint flow path to mix at a mixing valve capable of changing a flow rate and supply hot water at a desired temperature. In this, the required capacity of these heating means is derived at the time of hot water supply,
According to the derived required capacity, the control method of the heating means and the mixing valve is appropriately switched and controlled in accordance with the derived required capacity, and the required capacity is derived by storing the tap water temperature and the tap water amount obtained by the measurement in the storage means. Deriving the required capacity based on the previously stored values without updating the values if these values are within predetermined error ranges, respectively, by comparing them with these stored previous values. In addition, when the error exceeds the error range, the values are updated, and the required capacity is derived based on those values, so that the derived required capacity is affected by the measurement error and changes every time. Therefore, stable control can be performed without hunting, and a stable tapping temperature can be obtained.
There is an effect that the life of the control element can be prevented from being shortened.

[Brief description of the 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 sectional views showing the configuration and operation of an embodiment of a mixing valve. FIG. 3 is a flowchart showing a specific example of the entire control including the method of the present invention, and FIG. 4 is a flowchart showing the method of the present invention in detail. Reference numeral 1: hot water path 2 ... hot water heater 3 ... heat exchanger 4
… Mixing valve, 5… Water path, 6… Combined flow path, 7… Thermal response element, 8… Valve body, 9… Actuating mechanism, 10… Bias spring, 11… Actuating body, 12… ... heating means (burner), 13 ...
... Control means, 14 ... Tap water temperature setting device, 15 ... Temperature sensor, 16 ... Flow rate setting means, 17 ... Temperature sensor, 18 ... Total flow rate measurement means, 19 ... Tap hole, 20 ... Return spring .

Continuation of front page (72) Inventor Noritaka Morinaka 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Inside Takagi Sangyo Co., Ltd. (56) References JP-A-63-213747 (JP, A) JP-A-58-205043 ( JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F24H 1/00 302

Claims (4)

(57) [Claims] A water path is provided in parallel with a hot water path passing through a heat exchanger provided with a heating means, wherein the water path is branched at an upstream side of the heat exchanger and joined via a mixing valve at a downstream side. The valve is configured to change a flow rate ratio between the water path and the hot water path by moving a valve element by a thermally responsive element provided in the joint flow path,
The heat responsive element is biased by an operating mechanism in accordance with a tapping temperature set by a tapping temperature setter, and the heating means is controlled by a control means using a temperature sensor provided downstream of the heat exchanger. In a hot water mixing type instantaneous water heater configured to control and adjust the downstream hot water temperature to a predetermined temperature, the control means includes a hot water setting temperature, a clean water temperature and a hot water amount obtained by measurement. From the above, the required capacity of the heating means is derived, and the heating means and the mixing valve are controlled in accordance with the required capacity, and the storage means for the tap water temperature and the amount of hot water is provided. The obtained tap water temperature and tap water amount are compared with these stored values, and if they are within the predetermined error ranges, the values are not updated, but based on the stored values. The required capacity is derived by using If it exceeds updates the value, the method of deriving the required capacity of at heating means the hot water supply control of the hot and cold water mixing type instantaneous water heater which is characterized in that the derivation of the required capacity on the basis of those values 2. The control means according to claim 1, wherein said control means derives a required capacity of said heating means. If the required capacity is lower than a first set capacity in a low capacity area, said control means controls said heating means to a predetermined temperature in a high temperature area. ON-OFF control is performed in the temperature range, and when the required capacity is less than the second set ability that is set lower than the first set ability, the second set ability is calculated backward. ON-OFF as the hot water set temperature
Of Derivation of Required Capacity of Heating Means in Hot Water Supply Control of Hot Water Mixing Type Instant Water Heater with Control 3. A method for deriving a required capacity of a heating means in hot water supply control of a water / mixing type instantaneous water heater, wherein the heating means is a burner. 4. A hot water supply control system for a hot water / mixing type instantaneous water heater, characterized in that the heat responsive element according to claim 1 is configured to expand and contract according to ambient temperature by incorporating a wax. Derivation method of required capacity of heating means