JP2009063276A - Hot water storage type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water storage type water heater resolving a hunting phenomenon in a short time even when a hunting phenomenon occurs, and capable of improving durability of a mixing valve. <P>SOLUTION: The hot water storage type water heater is provided with a hot water storage tank 1 storing hot water, a first tapping pipe 12 tapping high temperature water than the hot water storage tank 1, a water supply pipe 3 supplying water, a first hot water/water mixing device 14 mixing hot water and water, a first hot water supply pipe 41 supplying hot water mixed by the first hot water/water mixing device 14 to a hot water supply terminal, a first flow rate detecting means 16 for detecting a flow rate of hot water, a first temperature detecting means 15 for detecting a temperature of hot water, and a controller 30 controlling the first hot water/water mixing device 14. When a temperature change state of detecting that the temperature detected by the first temperature detecting means 15 is a predetermined temperature higher with respect to a set temperature, and then detecting that it is a predetermined temperature lower with respect to the set temperature is detected a plurality of times by the controller 30, driving speed of the first hot water/water mixing device 14 is slowed down. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hot water storage type water heater, and more particularly to drive control of a mixing valve.

  A conventional water heater that stores hot water in a hot water storage tank and supplies hot water to a caran etc. mixes hot water in the hot water storage tank with water from a water supply source, and supplies hot water at an appropriate temperature to hot water terminals such as the caran etc. . However, depending on the driving speed of the mixing valve, the balance between the pressure of the hot water discharged from the hot water storage tank and the pressure of the water supplied from the water supply source may be lost, and as a result, the temperature of the hot water discharged from the mixing valve may become This causes a so-called hunting phenomenon that fluctuates up and down and causes overshoot and undershoot.

On the other hand, when supplying hot water to a hot water supply terminal such as a curan, at the same time as supplying hot water to a bathtub such as a bathroom, there is a possibility that a hunting phenomenon may occur in each mixing valve. The driving speed of the low-mixing valve was switched to the low speed mode (see, for example, Patent Document 1).
JP 2002-48409 A

  However, the conventional technique is control for preventing the hunting phenomenon, and is not control for eliminating the hunting phenomenon after the hunting phenomenon actually occurs. Therefore, when the hunting phenomenon occurs, the opening degree of the mixing valve is not stabilized for a long time, and the durability of the mixing valve is deteriorated.

  The present invention solves the above-described conventional problems, and provides a hot water storage type water heater that can eliminate the hunting phenomenon in a short time and improve the durability of the mixing valve even if the hunting phenomenon occurs. With the goal.

  In order to solve the above-mentioned conventional problems, a hot water storage type water heater of the present invention supplies hot water from a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper part of the hot water storage tank, and water from a water supply source A first hot water supply pipe that supplies hot water mixed by the first hot water mixing apparatus to a hot water supply terminal, a first hot water mixing apparatus that connects the first hot water pipe and the water supply pipe to mix hot water, and a hot water mixed by the first hot water mixing apparatus; First flow rate detection means for detecting the flow rate of hot water flowing through the first hot water supply pipe, first temperature detection means for detecting the temperature of hot water mixed on the downstream side of the first hot water / water mixing device, and the first hot water / water mixing And a control device for controlling the device, detecting that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and thereafter being equal to or lower than the predetermined temperature with respect to the set temperature. The temperature change state to detect that When detecting the occurrence of the hunting phenomenon by slowing down the driving speed of the first hot water / water mixing device when the apparatus is detected a plurality of times, the driving speed of the first hot water / water mixing device is slowed down, thereby eliminating the hunting phenomenon. And the durability of the mixing valve can be improved.

The hot water storage type water heater of the present invention includes a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, and the first A first hot water mixing apparatus that connects the hot water pipe and the water supply pipe to mix hot water, a first hot water supply pipe that supplies hot water mixed by the first hot water mixing apparatus to a hot water supply terminal, and the first hot water supply pipe A first flow rate detecting means for detecting the flow rate of hot water, a first temperature detecting means for detecting the temperature of hot water mixed on the downstream side of the first hot water / mixer, and a controller for controlling the first hot water / mixer. And detecting that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and then detecting the temperature below the predetermined temperature with respect to the set temperature. A state that periodically fluctuates in the control device When detecting multiple times, by driving the first hot and cold water mixing device to a predetermined position, it is possible to select the opening of the mixing valve in accordance with the use situation, so that the opening can be controlled, It is possible to suppress the hunting phenomenon from continuing for a long time.

  The hot water storage type water heater of the present invention includes a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, and the first A first hot water mixing device for connecting hot water pipe and the water supply pipe to mix hot water, a first hot water supply pipe for supplying hot water mixed by the first hot water mixing device to a hot water supply terminal, and flowing through the first hot water supply pipe A first flow rate detecting means for detecting the flow rate of hot water, a first temperature detecting means for detecting the temperature of hot water mixed on the downstream side of the first hot water / mixer, and a controller for controlling the first hot water / mixer. And detecting that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and then detecting the temperature below the predetermined temperature with respect to the set temperature. A state that periodically fluctuates in the control device When detecting a plurality of times, the first hot water / water mixing device is driven to a predetermined position, and the driving speed of the first hot water / water mixing device is decreased, so that the opening degree can be set according to the use situation, and the driving speed Furthermore, the hunting phenomenon can be surely suppressed because the delay is further delayed.

  Even if a hunting phenomenon occurs, the present invention can eliminate the hunting phenomenon in a short time and improve the durability of the mixing valve.

  The hot water storage type water heater of the first invention is a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper part of the hot water storage tank, a water supply pipe for supplying water from a water supply source, and the first A first hot water mixing apparatus that connects the hot water pipe and the water supply pipe to mix hot water, a first hot water supply pipe that supplies hot water mixed by the first hot water mixing apparatus to a hot water supply terminal, and the first hot water supply pipe A first flow rate detecting means for detecting the flow rate of hot water, a first temperature detecting means for detecting the temperature of hot water mixed on the downstream side of the first hot water / mixer, and a controller for controlling the first hot water / mixer. And a temperature change state in which it is detected that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and thereafter is detected to be equal to or lower than the predetermined temperature with respect to the set temperature. When the control device detects a plurality of times, If the occurrence of the hunting phenomenon is detected by slowing down the driving speed of the first hot water mixing device, the driving speed of the first hot water mixing device is slowed down, so that the hunting phenomenon can be eliminated and the durability of the mixing valve can be reduced. Can be improved.

  The hot water storage type hot water heater of the second invention is a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper part of the hot water storage tank, a water supply pipe for supplying water from a water supply source, and the first A first hot water mixing device for connecting hot water pipe and the water supply pipe to mix hot water, a first hot water supply pipe for supplying hot water mixed by the first hot water mixing device to a hot water supply terminal, and flowing through the first hot water supply pipe A first flow rate detecting means for detecting the flow rate of hot water, a first temperature detecting means for detecting the temperature of hot water mixed on the downstream side of the first hot water / mixer, and a controller for controlling the first hot water / mixer. And detecting that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and then detecting the temperature below the predetermined temperature with respect to the set temperature. The state where the control device periodically fluctuates When detected several times, by driving the first hot and cold water mixing device to a predetermined position, it is possible to select the opening of the mixing valve according to the use situation, so that the opening can be controlled, It is possible to suppress the hunting phenomenon from continuing for a long time.

  A hot water storage type water heater according to a third aspect of the invention is a hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, and the first A first hot water mixing apparatus that connects the hot water pipe and the water supply pipe to mix hot water, a first hot water supply pipe that supplies hot water mixed by the first hot water mixing apparatus to a hot water supply terminal, and the first hot water supply pipe A first flow rate detecting means for detecting the flow rate of hot water, a first temperature detecting means for detecting the temperature of hot water mixed on the downstream side of the first hot water / mixer, and a controller for controlling the first hot water / mixer. And detecting that the temperature detected by the first temperature detecting means is equal to or higher than a predetermined temperature with respect to a set temperature, and then detecting the temperature below the predetermined temperature with respect to the set temperature. The state where the control device periodically fluctuates When it is detected several times, the first hot water / water mixing device is driven to a predetermined position and the driving speed of the first hot water / water mixing device is slowed down so that the opening degree can be set according to the use situation. Furthermore, the hunting phenomenon can be surely suppressed because the delay is further delayed.

  The hot water storage type water heater according to the fourth aspect of the invention is particularly any one of the first to third aspects of the invention, wherein water is taken out from the lower part of the hot water storage tank and supplied to the heating unit, and hot water is generated by the heating unit. By supplying hot water to the upper portion of the hot water storage tank, hot water can be stored in the hot water storage tank in a stacked state, so that efficient boiling can be performed and hot water can be stirred in the hot water storage tank. Absent.

  In the hot water storage type water heater of the fifth invention, particularly in the fourth invention, the heating section is a heat pump, so that it is possible to perform efficient boiling.

  In the hot water storage type water heater of the sixth aspect of the invention, particularly in the fifth aspect of the invention, the refrigerant used for the heat pump is carbon dioxide, so that the product cost can be reduced and the reliability can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot water storage type water heater in the present embodiment. In FIG. 1, the hot water storage type water heater of the present embodiment has a hot water storage tank 1, stores hot water in the hot water storage tank 1, and supplies hot water in the hot water storage tank 1 to a hot water supply terminal or a bath. ing. A water supply port 2 is provided below the hot water storage tank 1, and water is supplied from the water supply source to the hot water storage tank 1 through the water supply pipe 3.

  The hot water in the hot water storage tank 1 is generated by the heat pump 4. The heat pump 4 includes a water refrigerant heat exchanger 5 that exchanges heat between water and refrigerant, a compressor 6 that compresses refrigerant, an evaporator 7 that exchanges heat between air and refrigerant, and a decompression device 8 through refrigerant piping. Since the refrigerant is made of carbon dioxide as the refrigerant, the high pressure side exceeds the critical pressure, so the water flowing through the water refrigerant heat exchanger 5 is deprived of heat and the temperature drops. In other words, the water / refrigerant heat exchanger 5 can easily form a temperature difference between the refrigerant and the water, so that hot water can be obtained and the heat exchange efficiency can be increased. In addition, since carbon dioxide, which is relatively inexpensive and stable, is used as the refrigerant, the product cost can be reduced and the reliability can be improved. In addition, carbon dioxide has an ozone depletion coefficient of zero and a global warming coefficient of about 1/700 of the alternative refrigerant HFC-407C, which is very small.

Further, in the heat pump 4, the refrigerant is compressed by the compressor 6, the refrigerant discharged from the compressor 6 radiates heat by the water refrigerant heat exchanger 5, is decompressed by the decompression device 8, and then is heated from the air by the evaporator 7. And is sucked into the compressor 6 again in a gas state. The compressor capacity control and the decompression device 8 opening control are performed so that the temperature of the discharged refrigerant detected by a thermistor (not shown) provided on the discharge side of the compressor 6 is maintained at a preset temperature. Controlled. The hot water in the hot water storage tank 1 flows into the water / refrigerant heat exchanger 5 when the water pump 9 is operated, exchanges heat with the refrigerant, returns to the hot water storage tank 1 again, and is stored in the stacked state in the hot water storage tank 1. Hot water is stored at the top.

  Next, the supply of hot water to the hot water supply terminal 10 such as a currant and the bathtub 11 will be described. In the upper part of the hot water storage tank 1, there are provided a first tapping pipe 12 that pours hot water into the hot water supply terminal 10 and a second tapping pipe 13 that pours hot water into the bathtub 11. However, in the present embodiment, the hot water outlet is provided at the top of the hot water storage tank 1, but the present invention is not limited to this. For example, the hot water outlet is provided at about 50 L above the hot water storage tank 1. There is no problem even if hot water is supplied.

  First, hot water supply to the hot water supply terminal 10 will be described. The hot water from the first hot water pipe 12 and the water supplied through the pipe branched from the water supply pipe 3 are mixed by an electric mixing valve 14 which is a first hot water mixing device. The first hot water supply pipe 41 downstream of the electric mixing valve 14 has a thermistor 15 as first temperature detecting means for detecting the temperature of hot water and a flow rate detecting device as first flow rate detecting means for detecting the flow rate of hot water. 16 is provided. Normally, the control of the electric mixing valve 14 is feedback control so that the temperature detected by the thermistor 15 becomes the set temperature set by the user.

  Similarly, hot water supply to the bathtub 11 will be described. High temperature water from the second hot water discharge pipe 13 and water supplied through a pipe branched from the water supply pipe 3 are mixed by an electric mixing valve 17 which is a second hot water mixing apparatus. Downstream of the electric mixing valve 17, there are provided a thermistor 18 as second temperature detecting means for detecting the temperature of hot water and a flow rate detecting device 19 as second flow rate detecting means for detecting the flow rate of hot water. Between the thermistor 18 and the flow rate detection device 19, an electromagnetic valve 20 for starting / stopping the supply of hot water to the bathtub 11 is provided. When hot water is supplied to the bathtub 11, the electromagnetic valve 20 is opened to open the hot water. Start supplying. The electric mixing valve 17 is also controlled so that the temperature detected by the thermistor 18 becomes the set temperature set by the user. In addition, the hot water storage type water heater of the present embodiment is provided with a controller 30, which obtains data from an electric mixing valve and flow rate detection means and performs control.

  FIG. 2 is a table display of the driving speed in the normal control of the mixing valve in the present embodiment. For example, when the flow rate of hot water detected by the flow rate detection device 16 is 4.0 L / min and the absolute value of the difference between the thermistor 15 and the set temperature is 4.0 K, the electric mixing is performed according to FIG. Since the driving speed of the valve 14 is determined, the electric mixing valve 14 is driven at a driving speed of 100.0 (Pulse / Second). In the present embodiment, a flow rate of less than 2.5 L / min is defined as a low flow rate, a flow rate of less than 4.0 L / min is defined as a medium flow rate, and a flow rate of 4.0 / min or more is defined as a high flow rate. The driving speed of the electric mixing valve 14 is determined according to the table shown.

  However, as shown in FIG. 2, when the driving speed when the temperature deviation is 14K or higher is seen, the driving speed is fast, so if the hunting phenomenon is continued while the driving speed is high, the hunting phenomenon does not converge. Since the durability of the mixing valve is deteriorated, it is necessary to eliminate the hunting phenomenon. In the present embodiment, in order to eliminate the hunting phenomenon, when a hunting phenomenon under a certain condition is detected, a table of the mixing valve driving speed of the hunting elimination control is used instead of the table of the mixing valve driving speed of the normal control. By doing so, the fluctuation range in which the temperature fluctuates up and down is reduced, and the hunting phenomenon is eliminated.

The specific control at the time of the independent hot water supply to the hot water supply terminal 10 is demonstrated using the flowchart of FIG. In FIG. 3, in STEP 1, the flow rate is detected by the flow rate detection device 16, and a large flow rate (4.0 L / min or more), a medium flow rate (2.5 L / min or more, less than 4.0 L / min), or a small flow rate. Determine whether the flow rate (less than 2.5 L / min). In addition, the threshold value at the time of determining a flow area is not limited to this, It can change suitably according to use of a system.

  Next, in STEP 2, normal control is performed at a driving speed (shown in FIG. 2) determined from the current flow rate and the difference (temperature deviation) between the temperature detected by the thermistor 15 and the set temperature. For example, when the flow rate of hot water supplied to the current hot water supply terminal detects 4.0 L / min, a large flow rate is selected. Further, when the difference between the temperature detected by the thermistor 15 and the set temperature is 4K, 100.0 (PPS) is selected from FIG. 2 and the drive is controlled.

  Next, in STEP 3, the temperature detected by the thermistor 15 detects a set temperature + predetermined temperature or more, and then detects a set temperature−predetermined temperature or less. Detect if it happens multiple times.

  FIG. 4 shows a state where the temperature fluctuates up and down by a predetermined temperature across the set temperature. As shown in FIG. 4, by detecting a set temperature + predetermined temperature or more, and then detecting the set temperature−predetermined temperature or less as one period, the hunting phenomenon is detected by detecting this period a plurality of times. Is determined to have occurred. In the following description, the preset temperature is 40 ° C. and the predetermined temperature is 14 ° C., but the present invention is not limited to this.

  For example, when the set temperature is set to 40 ° C., the temperature detected by the thermistor 15 is 54 ° C. (40 ° C. + 14 ° C.) or higher, and then 26 ° C. (40 ° C.-14 ° C.) or lower. When periodically detected, if this cycle is detected a plurality of times (in this embodiment, three times), it is determined that a hunting phenomenon has occurred.

  If the hunting phenomenon has not occurred, normal control is performed at STEP 4 at the driving speed shown in FIG. However, if it is determined in STEP 3 that the hunting phenomenon has occurred, hunting elimination control is performed at the driving speed shown in FIG.

  As shown in FIG. 5, in the hunting elimination control as compared with the normal control, the drive speed is controlled using a drive speed that is approximately halved compared to the normal control. When the hunting phenomenon is detected in this way, the driving speed is made slower than that in the normal control, so that the duration of the hunting phenomenon can be suppressed to a short time, so that comfortable temperature control can be performed. In this embodiment, the driving speed of the hunting elimination control is set to about half of the driving speed of the normal control. However, the driving speed is not limited to this and can be changed according to the system specifications.

(Embodiment 2)
Since the configuration of the hot water storage type hot water heater in the second embodiment is the same as the configuration of the hot water storage type hot water heater in the first embodiment, the same reference numerals as those in the first embodiment are given and the description thereof is omitted. In the first embodiment, the control of the electric mixing valve 14 or the electric mixing valve 17 detects the hunting phenomenon and then changes the driving speed to eliminate the hunting phenomenon. In the second embodiment, the driving method of the electric mixing valve 14 or the electric mixing valve 17 is changed from the first embodiment, and other controls are the same as those in the first embodiment.

  The drive of the normal electric mixing valve 14 or the electric mixing valve 17 in the second embodiment is the temperature of the thermistor provided on the downstream side of the electric mixing valve 14 (17) as in the first embodiment. The feedback control is performed while detecting. The electric mixing valve 14 (17) is driven at a driving speed that varies depending on the flow rate shown in the table of FIG.

  Further, the specific control at the time of independent hot water supply to the hot water supply terminal 10 is based on the flowchart of FIG. 3 as in the first embodiment. In FIG. 3, in STEP 1, the flow rate is detected by the flow rate detection device 16, and a large flow rate (4.0 L / min or more), a medium flow rate (2.5 L / min or more, less than 4.0 L / min), or a small flow rate. Determine whether the flow rate (less than 2.5 L / min). In addition, the threshold value at the time of determining a flow area is not limited to this, It can change suitably according to use of a system.

  Next, in STEP 2, normal control is performed at a driving speed (shown in FIG. 2) determined from the current flow rate and the difference (temperature deviation) between the temperature detected by the thermistor 15 and the set temperature. For example, when the flow rate of hot water supplied to the current hot water supply terminal detects 4.0 L / min, a large flow rate is selected. Further, when the difference between the temperature detected by the thermistor 15 and the set temperature is 4K, 100.0 (PPS) is selected from FIG. 2 and the drive is controlled.

  Next, in STEP 3, the temperature detected by the thermistor 15 detects a set temperature + predetermined temperature or more, and then detects a set temperature−predetermined temperature or less. Detect if it happens multiple times.

  FIG. 4 shows a state where the temperature fluctuates up and down by a predetermined temperature across the set temperature. As shown in FIG. 4, by detecting a set temperature + predetermined temperature or more, and then detecting the set temperature−predetermined temperature or less as one period, the hunting phenomenon is detected by detecting this period a plurality of times. Is determined to have occurred. In the following description, the preset temperature is 40 ° C. and the predetermined temperature is 14 ° C., but the present invention is not limited to this.

  For example, when the set temperature is set to 40 ° C., the temperature detected by the thermistor 15 is 54 ° C. (40 ° C. + 14 ° C.) or higher, and then 26 ° C. (40 ° C.-14 ° C.) or lower. When periodically detected, if this cycle is detected a plurality of times (in this embodiment, three times), it is determined that a hunting phenomenon has occurred.

  If the hunting phenomenon has not occurred, normal control is performed at STEP 4 at the driving speed shown in FIG. However, if it is determined in STEP 3 that the hunting phenomenon has occurred, the electric mixing valve 14 is driven so that the opening degree is as shown in FIG. For example, if the flow rate detection means detects a low flow rate, the opening degree of the mixing valve is controlled so that the opening degree of the electric mixing valve is 90% on the hot water side.

  As shown in FIG. 6, compared to the normal control, in the hunting elimination control, the opening degree is set in advance and then feedback control based on the thermistor is performed, so that the hunting phenomenon can be eliminated. In addition, as shown in FIG. 6, the lower flow rate has a larger opening on the hot water side than the large flow rate, but this is because the lower the flow rate, the less hot water is supplied. In order to secure hot water, the lower the flow rate, the larger the opening on the hot water side, and the temperature is mixed at an appropriate temperature. In addition, the opening degree set beforehand shown in FIG. 6 is an experimental value, and can be changed according to the situation.

  Further, the hunting phenomenon can be reliably converged by changing the driving speed after setting to a preset opening degree to a slow driving speed as shown in the first embodiment.

  As described above, by controlling the mixing valve at an opening degree corresponding to the flow rate, the hunting phenomenon can be converged and more comfortable temperature control can be performed. Furthermore, the electric mixing valve failure due to the motor lock abnormality of the electric mixing valve can be eliminated.

  As described above, the present invention is not limited to a heat pump type hot water storage water heater, and can be used for a water heater using a mixing valve in any system such as electricity, gas, oil, and fuel cell.

The system block diagram of the hot water storage type water heater in Embodiment 1 of this invention The figure which showed the drive speed of the electric mixing valve in the embodiment Control chart of electric mixing valve in the same embodiment Hot water temperature change diagram of the electric mixing valve in the same embodiment The figure which showed the drive speed of the electric mixing valve in the embodiment The figure which showed the drive opening degree of the electric mixing valve in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Water supply port 3 Water supply pipe 4 Heat pump 5 Water refrigerant | coolant heat exchanger 6 Compressor 7 Evaporator 8 Pressure reducing device 9 Water pump 10 Hot water supply terminal 11 Bath 12 First hot water pipe 13 Second hot water pipe 14 Electric mixing valve 15 Thermistor 16 Flow rate detector 17 Electric mixing valve 18 Thermistor 19 Flow rate detector 20 Solenoid valve

Claims (6)

A hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, the first hot water discharge pipe and the water supply pipe are connected to make hot water A first hot water mixing device for mixing hot water, a first hot water supply pipe for supplying hot water mixed by the first hot water mixing device to a hot water supply terminal, and a first flow rate detecting means for detecting the flow rate of hot water flowing through the first hot water supply pipe And a first temperature detecting means for detecting the temperature of the hot and cold water mixed on the downstream side of the first hot and cold water mixing device, and a control device for controlling the first hot and cold water mixing device, which is detected by the first temperature detecting means. A state in which the detected temperature is equal to or higher than a predetermined temperature with respect to the set temperature, and then the state in which the temperature to be detected as being lower than the predetermined temperature with respect to the set temperature is periodically fluctuated up and down is controlled. When the device detects a plurality of times, the first Hot water storage type water heater, characterized by slowing the drive speeds of the water mixing device. A hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, the first hot water discharge pipe and the water supply pipe are connected to make hot water A first hot water mixing device for mixing hot water, a first hot water supply pipe for supplying hot water mixed by the first hot water mixing device to a hot water supply terminal, and a first flow rate detecting means for detecting the flow rate of hot water flowing through the first hot water supply pipe And a first temperature detecting means for detecting the temperature of the hot and cold water mixed on the downstream side of the first hot and cold water mixing device, and a control device for controlling the first hot and cold water mixing device, which is detected by the first temperature detecting means. A state in which the detected temperature is equal to or higher than a predetermined temperature with respect to the set temperature, and then the state in which the temperature to be detected as being lower than the predetermined temperature with respect to the set temperature is periodically fluctuated up and down is controlled. When the device detects a plurality of times, the first Hot water storage type water heater, which comprises driving the water mixing device in a predetermined position. A hot water storage tank for storing hot water, a first hot water discharge pipe for discharging hot water from an upper portion of the hot water storage tank, a water supply pipe for supplying water from a water supply source, the first hot water discharge pipe and the water supply pipe are connected to make hot water A first hot water mixing device for mixing hot water, a first hot water supply pipe for supplying hot water mixed by the first hot water mixing device to a hot water supply terminal, and a first flow rate detecting means for detecting the flow rate of hot water flowing through the first hot water supply pipe And a first temperature detecting means for detecting the temperature of the hot and cold water mixed on the downstream side of the first hot and cold water mixing device, and a control device for controlling the first hot and cold water mixing device, which is detected by the first temperature detecting means. A state in which the detected temperature is equal to or higher than a predetermined temperature with respect to the set temperature, and then the state in which the temperature to be detected as being lower than the predetermined temperature with respect to the set temperature is periodically fluctuated up and down is controlled. When the device detects a plurality of times, the first It drives the water mixing device in a predetermined position, storage-type water heater, characterized by slowing the drive speeds of the first hot and cold water mixing device. The water is taken out from the lower part of the hot water storage tank and supplied to the heating unit, hot water is generated by the heating unit, and hot water is supplied to the upper part of the hot water storage tank. The hot water storage water heater described in 1. The hot water storage type water heater according to claim 4, wherein the heating unit is a heat pump. The hot water storage type hot water heater according to claim 5, wherein the refrigerant used in the heat pump is carbon dioxide.

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