HOT WATER APPARATUS

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This application claims the priority benefits of Japanese application no. 2024-060684, filed on Apr. 4, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

[0002]The disclosure relates to a hot water apparatus such as a hot water supply apparatus.

RELATED ART

[0003]Patent Literature 1 (Japanese Patent No. 3674014) describes a hot water apparatus as a specific example.

[0004]The hot water apparatus described in this literature includes a heat exchanger capable of heating hot water using a burner, and a water inlet passage and a hot water outlet passage respectively connected to the inlet side and the outlet side of this heat exchanger are connected to each other via a bypass passage. This allows heated hot water heated by the heat exchanger to flow through the hot water outlet passage while mixing unheated bypass hot water flowing through the bypass passage with this heated hot water. The respective flow rates of the heated hot water and bypass hot water can be changed using, for example, two flow control valves (heat exchanger flow control valve, bypass flow control valve), thereby setting the temperature of the mixed hot water to or bringing the temperature close to a desired target hot water supply temperature.

[0005]On the other hand, in the aforementioned hot water apparatus, when there is output of abnormally high-temperature hot water, in which hot water at a predetermined high temperature or above is output from the hot water outlet to the exterior, or there is such a risk, this is detected by a predetermined means. In addition, when this is detected, both the two flow control valves are fully closed, and the flow of hot water is blocked, which appropriately suppresses the occurrence of output of abnormally high-temperature hot water.

[0006]However, in the aforementioned related technology, there are issues to be resolved, as described below.

[0007]That is, there are valve devices described in Patent Literatures 2 and 3 (Japanese Patent No. 5004674 and Japanese Patent No. 3812614) as specific examples of valve devices, and in some cases, it may be desired to use such valve devices in place of the two flow control valves in the aforementioned hot water apparatus. More specifically, the valve devices described in Patent Literatures 2 and 3 are so-called three-way valves, and it is possible to use such a valve device as a mixing valve that enables heated hot water heated by the heat exchanger and unheated bypass hot water to flow into the first and second ports of this valve device, and enables the mixed hot water to flow out from the third port. In this case, it is possible to sequentially execute flow rate control in a temperature adjustment range mode, in which the flow rate of heated hot water gradually increases while the flow rate of bypass hot water gradually decreases, and flow rate control in a flow rate adjustment range mode, in which the flow rate of heated hot water gradually decreases while the flow rate of bypass hot water is maintained at a predetermined minimum flow rate, in the process where the rotation angle of the motor drive shaft for a valve operation changes from a predetermined first angle to a second angle. With such a configuration, the total number of valve devices (flow control valves) used in the hot water apparatus can be reduced, making it possible to achieve simplification of the overall configuration of the hot water apparatus and reduction of manufacturing cost.

[0008]On the other hand, in the case of using the aforementioned valve device, it is conceivable to increase the rotation angle of the motor drive shaft of the valve device, and set the valve device to a state where the flow rate of heated hot water is zero and the flow rate of bypass hot water is zero in the flow rate adjustment range mode, as a means to prevent output of high-temperature hot water, when the hot water apparatus has abnormality in outputting high-temperature hot water or when there is such a risk.

[0009]However, if such a means is adopted, the flow rate of heated hot water increases at the stage where the valve device transitions, for example, from the temperature adjustment range mode to the flow rate adjustment range mode. In this case, high-temperature hot water output is not immediately prevented, and during the period before hot water output is prevented, there is a risk that the flow rate ratio of heated hot water to bypass hot water may increase temporarily, and the hot water outlet temperature may actually become higher. It is required to appropriately prevent such a risk.

[0010]The disclosure, conceived under the aforementioned circumstances, aims to provide a hot water apparatus that is capable of appropriately preventing or suppressing output of abnormally high-temperature hot water while using a valve device capable of flow rate control in a predetermined temperature adjustment range mode and a flow rate adjustment range mode, as a hot water flow rate control means.

SUMMARY

[0011]The disclosure employs the following technical means.

[0012]A hot water apparatus provided by the disclosure includes: a water inlet passage and a hot water outlet passage respectively connected to an inlet side and an outlet side of a heat exchanger for hot water heating; a bypass passage bypassing the heat exchanger to connect the water inlet passage and the hot water outlet passage to each other, and mixing hot water from the water inlet passage, as bypass hot water, with heated hot water flowing through the hot water outlet passage; a valve device capable of changing a flow rate of the heated hot water flowing through the hot water outlet passage and a flow rate of the bypass hot water flowing through the bypass passage; and an abnormality detection part capable of detecting occurrence or risk of output of abnormally high-temperature hot water in which hot water at a predetermined high temperature or above is output from the hot water outlet passage to exterior. The valve device is configured to be capable of sequentially executing flow rate control in a temperature adjustment range mode and flow rate control in a flow rate adjustment range mode in a process where a rotation angle of a motor drive shaft for a valve operation changes between a predetermined first angle and a second angle. The flow rate control in the temperature adjustment range mode gradually increases the flow rate of the heated hot water while gradually decreasing the flow rate of the bypass hot water, and the flow rate control in the flow rate adjustment range mode changes a total flow rate of hot water flowing through the valve device so that the flow rate of the heated hot water gradually decreases while the flow rate of the bypass hot water is maintained at or below a predetermined minimum flow rate. When occurrence or risk of output of abnormally high-temperature hot water is detected by the abnormality detection part, in a case where the valve device is in the temperature adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to the first angle, and in a case where the valve device is in the flow rate adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to the second angle.

[0013]This configuration provides the following effects. That is, when output of abnormally high-temperature hot water has occurred or is likely to occur, in a case where the valve device is in the temperature adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to the first angle. In this case, the flow rate of the bypass hot water increases while the flow rate of the heated hot water decreases. On the other hand, when output of abnormally high-temperature hot water has occurred or is likely to occur, in a case where the valve device is in the flow rate adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to the second angle. In this case, the flow rate of the heated hot water gradually decreases while the flow rate of the bypass hot water is maintained at or below the predetermined minimum flow rate. Therefore, in either case, the flow rate ratio of heated hot water to bypass hot water does not temporarily increase, and the flow rate of heated hot water can be sequentially reduced to zero or brought close to zero. Consequently, it is possible to appropriately prevent or suppress output of abnormally high-temperature hot water without causing a malfunction that the hot water outlet temperature rises temporarily.

[0014]In the disclosure, when occurrence or risk of output of abnormally high-temperature hot water is detected by the abnormality detection part, in a case where the valve device is at a boundary between the temperature adjustment range mode and the flow rate adjustment range mode, control may be executed to set the rotation angle of the motor drive shaft to an angle among the first angle and the second angle on a side where an angle difference from the boundary is small.

[0015]With this configuration, when output of abnormally high-temperature hot water has occurred or is likely to occur, in a case where the valve device is at the boundary between the temperature adjustment range mode and the flow rate adjustment range mode, it is possible to minimize the time until the flow rate of heated hot water is reduced to zero in the valve device thereafter.

[0016]Other features and advantages of the disclosure will become more apparent from the description of the embodiments of the disclosure given below with reference to the attached figures.

BRIEF DESCRIPTION OF DRAWINGS

[0017]FIG. 1 is a schematic explanatory diagram showing an example of the hot water apparatus according to the disclosure.

[0018]FIG. 2A is a partial side sectional view showing the valve device of the hot water apparatus in FIG. 1, FIG. 2B is a partial side sectional view at a part, different from FIG. 2A, of the valve device of the hot water apparatus in FIG. 1, and FIG. 2C is a bottom view of the valve device of the hot water apparatus in FIG. 1.

[0019]FIG. 3A is a partial side view of the valve body of the valve device shown in FIG. 2A to FIG. 2C, and FIG. 3B is a bottom view thereof.

[0020]FIG. 4A is a partial plan sectional view of the valve device shown in FIG. 2A to FIG. 2C, FIG. 4B is a partial plan sectional view of a part, different from FIG. 4A, of the valve device shown in FIG. 2A to FIG. 2C, and FIG. 4C is a bottom view of the valve device corresponding to FIG. 4A and FIG. 4B.

[0021]FIG. 5A is a sectional view showing a state where the valve body is rotated by a predetermined angle in the portion shown in FIG. 4A, FIG. 5B is a sectional view showing a state where the valve body is rotated by a predetermined angle in the portion shown in FIG. 4B, and FIG. 5C is a bottom view of the valve device corresponding to FIG. 5A and FIG. 5B.

[0022]FIG. 6A is a sectional view showing a state where the valve body is further rotated by a predetermined angle in the portion shown in FIG. 5A, FIG. 6B is a sectional view showing a state where the valve body is further rotated by a predetermined angle in the portion shown in FIG. 5B, and FIG. 6C is a bottom view of the valve device corresponding to FIG. 6A and FIG. 6B. FIG. 7 is an explanatory diagram showing the control mode of the valve device shown in FIG. 2A to FIG. 2C.

[0023]FIG. 8 is a flowchart showing an example of the operation processing procedure executed in the hot water apparatus shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

[0024]The following describes specifically exemplary embodiments of the disclosure with reference to the figures.

[0025]A hot water apparatus WH shown in FIG. 1 is configured as a hot water supply apparatus, and includes a premixing device 3, a combustion device C (premixing combustion device), a heat exchanger 11, hot water passages 40 to 42 to be described later, a valve device A, a controller 5, and an outer case 19 that houses these components internally and has a water inlet 43 and a hot water outlet 44.

[0026]The combustion device C is configured by combining a fan 1 and a burner part 2 with the premixing device 3. The premixing device 3 is a device that generates a gaseous mixture (combustible gaseous mixture) of air and fuel gas. The gaseous mixture is supplied to the burner part 2 by driving the fan 1. The burner part 2 has a configuration in which a porous plate 21 with multiple ventilation holes 20 is housed in a case 10, and an ignition plug 22 is attached. The gaseous mixture passes through the multiple ventilation holes 20, and combusts below the porous plate 21. Combustion gas generated by the burner part 2 acts on the heat exchanger 11, and the hot water passing through this heat exchanger 11 is heated. The heat exchanger 11 includes, for example, a primary heat exchange part 11A and a secondary heat exchange part 11B for sensible heat recovery and latent heat recovery, but is not limited thereto, and can also be configured with only the heat exchange part 11A for sensible heat recovery. After passing through the heat exchanger 11, the combustion gas passes through an exhaust duct part 10a of the case 10 and is discharged to the exterior as exhaust gas.

[0027]The water inlet 43 is, for example, a part where a water pipe is connected, and unheated hot water is supplied from the exterior. The hot water outlet 44 is a part for outputting hot water heated by the heat exchanger 11 to an external hot water outlet destination.

[0028]The hot water apparatus WH has hot water passages including a water inlet passage 40, a hot water outlet passage 41, and a bypass passage 42.

[0029]Here, the water inlet passage 40 is a hot water passage from the water inlet 43 to an inlet 11a of the heat exchanger 11. The water inlet passage 40 is provided with the valve device A, a flow rate sensor Sa, and a temperature sensor Sb for detecting the water inlet temperature. The water inlet passage 40 is divided into two passages 40a and 40b, which are located on the upstream side and downstream side of the valve device A, respectively.

[0030]The hot water outlet passage 41 is a hot water passage from an outlet 11b of the heat exchanger 11 to the hot water outlet 44. The hot water outlet passage 41 is provided with a temperature sensor Sc for detecting an outlet side temperature of the heat exchanger 11, a temperature sensor Sd for detecting abnormally high temperatures, and a temperature sensor Se for detecting the hot water temperature (hot water outlet temperature) on the downstream side of the connection point of the bypass passage 42.

[0031]The combination of the temperature sensors Sc and Sd and the controller 5, as will be described later, constitutes the “abnormality detection part” referred to in the disclosure.

[0032]The bypass passage 42 is a hot water passage that connects a part of the valve device A, which corresponds to an intermediate point of the water inlet passage 40, to an intermediate point Pa of the hot water outlet passage 41 to bypass the heat exchanger 11. Part of the hot water flowing through the water inlet passage 40 can be passed through the bypass passage 42 to flow into the intermediate point Pa of the hot water outlet passage 41. This makes it possible to generate mixed hot water with adjusted temperature by mixing the heated hot water in the hot water outlet passage 41 with the bypass hot water flowing through the bypass passage 42, and to output this mixed hot water from the hot water outlet 44.

[0033]The valve device A is a device capable of changing a flow rate Qa of the heated hot water flowing through the hot water outlet passage 41 and a flow rate Qb of the bypass hot water flowing through the bypass passage 42.

[0034]In FIG. 2A to FIG. 2C, the valve device A includes a case 6 having a first port P1 to a third port P3, a valve body 7 (7A, 7B) as a rotary valve body disposed in this case 6, and a drive shaft 8 (motor drive shaft 8) of a motor M for rotating this valve body 7.

[0035]The motor M is, for example, a stepping motor, and rotation angle control of the drive shaft 8 connected to the valve body 7 is possible.

[0036]In this embodiment, the valve device A is set to be used as a distribution valve that enables hot water flowing into the third port P3 to flow out to the first port P1 and the second port P2 (refer also to FIG. 1). The passage 40a on the upstream side of the water inlet passage 40 is connected to the third port P3, and unheated hot water supplied to the water inlet 43 flows in. The passage 40b on the downstream side of the water inlet passage 40 is connected to the second port P2, and the hot water flowing out from this second port P2 is sent to the heat exchanger 11. The bypass passage 42 is connected to the first port P1, and the hot water flowing out from this first port P1 flows through the bypass passage 42, and flows into the intermediate point Pa of the hot water outlet passage 41.

[0037]In FIG. 2A to FIG. 2C, partition wall parts 61a to 63a forming openings 61 to 63 for passing water are provided at positions close to the valve body 7 inside each of the first port P1 to the third port P3 of the case 6.

[0038]Further, the valve body 7 is a combination of a substantially cylindrical first valve body 7A that is open on the third port P3 side, and a second valve body 7B that is connected to the lower part of the first valve body 7A and rotates with the rotation of the first valve body 7A.

[0039]In the peripheral wall part of the first valve body 7A, a first opening 71 and a second opening 72 for passing water are provided to extend in the circumferential direction. The second valve body 7B is provided with a third opening 73 for communication with the third port P3, and a blocking part 74 that is fan-shaped when viewed from the bottom (refer also to FIG. 3A and FIG. 3B). The hot water flowing into the third port P3 can flow into the inside of the valve body 7 through the third opening 63, and then flow to the first port P1 and the second port P2 from the first opening 71 and the second opening 72 through the openings 61 and 62.

[0040]As shown in FIG. 7, the valve device A is capable of sequentially executing flow rate control in a temperature adjustment range mode and flow rate control in a flow rate adjustment range mode by changing the rotation angle of the motor drive shaft 8 and the valve body 7.

[0041]More specifically, the rotation angle of the motor drive shaft 8 and the valve body 7 can be changed from a predetermined first angle al to a second angle α2 beyond a predetermined boundary angle α3. The angular arrangement of the valve body 7 shown in FIG. 4A to FIG. 4C corresponds to the first angle α1. FIG. 5A to FIG. 5C and FIG. 6A to FIG. 6C correspond to the boundary angle α3 and the second angle α2, respectively.

[0042]When setting the first angle a1 as shown in FIG. 4A to FIG. 4C, the flow rate Qb of the bypass hot water is at the maximum, and the flow rate Qa of the heated hot water flowing through the hot water outlet passage 41 is zero.

[0043]That is, in this state, the third opening 63 is not blocked by the valve body 7 (second valve body 7B), allowing hot water to flow into the valve body 7. On the other hand, the communication area between the first opening 71 and the first port P1 is large, allowing a large amount of hot water to flow from the first port P1 to the bypass passage 42. The second opening 72 and the second port P2 are not in communication, so no hot water flows from the second port P2 to the heat exchanger 11.

[0044]From the first angle al to the boundary angle α3 is the temperature adjustment range mode. In this temperature adjustment range mode, as the rotation angle of the drive shaft 8 and the valve body 7 increases, the flow rate Qb of the bypass hot water gradually decreases, while the flow rate Qa of the heated hot water flowing through the hot water outlet passage 41 gradually increases.

[0045]That is, while the valve body 7 rotates in the direction indicated by arrow Da from the state shown in FIG. 4A to FIG. 4C to the angle shown in FIG. 5A to FIG. 5C, the communication opening area between the first opening 71 and the first port P1 gradually decreases. Therefore, the flow rate Qb of the bypass hot water gradually decreases. The first opening 71, as shown in FIG. 4A, extends in the circumferential direction at an appropriate angle θ1, but the vertical width W1 thereof (FIG. 3A and FIG. 3B) becomes narrower as it moves away from one end 71a. In contrast, the communication area between the second opening 72 and the second port P2 gradually increases. The second opening 72, as shown in FIG. 4B, extends in the circumferential direction at an appropriate angle θ2, but the vertical width W2 thereof becomes wider as it moves away from one end 72a.

[0046]In the configuration shown in FIG. 5A, when the rotation angle of the valve body 7 (and the motor drive shaft 8) is at the boundary angle α3, the flow rate Qb of the bypass hot water becomes zero. Alternatively, it may be configured so that the flow rate becomes a small amount close to zero (the virtual line portion in FIG. 7).

[0047]From the boundary angle α3 to the second angle α2 is the flow rate adjustment range mode. In this flow rate adjustment range mode, as the rotation angle of the motor drive shaft 8 and the valve body 7 increases, while maintaining the flow rate Qb of the bypass hot water at or below a predetermined minimum flow rate (zero or a small amount close to zero), the total flow rate of hot water flowing through the valve device A is changed so that the flow rate Qa of the heated hot water flowing through the hot water outlet passage 41 gradually decreases. Eventually, the flow rates Qb and Qa of the bypass hot water and heated hot water both become zero.

[0048]That is, when the valve body 7 reaches the angle shown in FIG. 6A to FIG. 6C, the opening 63 for passing water is completely closed by the blocking part 74 of the second valve body 7B, and hot water no longer flows into the third port P3. As a result, the flow rates Qa and Qb become zero. In the process of the valve body 7 changing from FIG. 5A to FIG. 5C to FIG. 6A to FIG. 6C, although the second opening 72 and the second port P2 are in communication, the opening area of the opening 63 for passing water gradually decreases, and the flow rate of hot water into the third port P3 and the inside of the valve body 7 decreases, causing the flow rate Qa to decrease.

[0049]In the flow rate adjustment range mode, the total flow rate of hot water flowing through the valve device A may be changed while maintaining the ratio of the flow rate of the bypass hot water to the flow rate of the heated hot water at the boundary angle α3.

[0050]The controller 5 is configured using a microcomputer or the like, and executes operation control and data processing of each part of the hot water apparatus WH, as well as controls the operation of the valve device A. This controller 5 is capable of detecting a situation when the temperature detected by the temperature sensors Sc and Sd is abnormally higher than a predetermined reference temperature, and output of abnormally high-temperature hot water has occurred or is likely to occur, in which hot water at a predetermined high temperature or above is output from the hot water outlet 44 to the exterior. When this is detected, the controller 5 causes the valve device A to perform a predetermined operation to prevent or suppress abnormally high-temperature hot water from being output from the hot water outlet 44. Nevertheless, the details will be described later.

[0051]It should be noted that a remote control (not shown) installed in the kitchen or bathroom is communicatively connected to the controller 5, and by using this remote control, the target hot water supply temperature, etc. can be set appropriately.

[0052]Next, an example of the operation processing procedure of the aforementioned hot water apparatus WH will be described with reference to the flowchart in FIG. 8, together with the function of the hot water apparatus WH.

[0053]First, during normal times when the hot water apparatus WH is not executing a hot water supply operation, the motor drive shaft 8 and the valve body 7 of the valve device A are controlled to be at the boundary angle α3 (S1). Next, when a hot water supply terminal (not shown) connected by piping to the hot water outlet 44 of the hot water apparatus WH is opened, hot water starts to flow to the water inlet passage 40, and the flow rate of hot water flowing through the heat exchanger 11 becomes equal to or greater than a predetermined minimum operating flow rate (MOQ-ON), which is detected based on the detection signal from the flow rate sensor Sa, the burner part 2 is turned on (S2: YES, S3). As a result, hot water heating using the heat exchanger 11 begins, and hot water output from the hot water outlet 44 is initiated. During such a hot water supply operation, the controller 5 executes a normal operation to control the flow rate Qa of heated hot water and the flow rate Qb of bypass hot water in the valve device A so that the hot water outlet temperature from the hot water outlet 44 becomes the desired target hot water supply temperature (S4).

[0054]During the aforementioned hot water supply operation, if it is determined in the controller 5 that output of abnormally high-temperature hot water has occurred or is likely to occur, the burner part 2 is driven off (S5: YES, S6), and the following operation control is executed.

[0055]That is, in a case where the valve device A is in the aforementioned temperature adjustment range mode at this time point, control is executed to set the rotation angle of the motor drive shaft 8 and the valve body 7 to the first angle α1 (S7, S8: YES, S9). In the process of executing this control, as understood from FIG. 7, the flow rate Qb of bypass hot water gradually increases, while the flow rate Qa of heated hot water decreases. When the first angle al is reached, the flow rate Qb of bypass hot water becomes maximum, and the flow rate Qa of heated hot water becomes zero. Therefore, the hot water outlet temperature from the hot water outlet 44 can be lowered without a rise even temporarily, making it possible to prevent or suppress output of abnormally high-temperature hot water.

[0056]Unlike the aforementioned operation control, if control is performed to set the rotation angle to the second angle α2 despite that the valve device A is in the temperature adjustment range mode when it is determined that output of abnormally high-temperature hot water has occurred or is likely to occur, the flow rate Qa of heated hot water increases during the period until the boundary angle α3 is reached, causing the hot water outlet temperature to rise. According to this embodiment, such a problem can be appropriately avoided.

[0057]Different from the aforementioned, in a case where the valve device A is in the aforementioned flow rate adjustment range mode when it is determined that output of abnormally high-temperature hot water has occurred or is likely to occur, control is executed to set the rotation angle of the motor drive shaft 8 and the valve body 7 to the second angle α2 (S8: NO, S10: YES, S11). In the process of executing this control, while the flow rate Qb of bypass hot water is maintained at a predetermined minimum flow rate, the flow rate Qa of heated hot water decreases. Eventually, both the flow rate Qb of bypass hot water and the flow rate Qa of heated hot water become zero. Therefore, in this case, the hot water outlet temperature from the hot water outlet 44 can also be lowered without a rise even temporarily, making it possible to prevent or suppress output of abnormally high-temperature hot water.

[0058]Unlike the aforementioned operation control, if control is performed to set the rotation angle to the first angle α1 despite that the valve device A is in the flow rate adjustment range mode when it is determined that output of abnormally high-temperature hot water has occurred or is likely to occur, the flow rate Qa of heated hot water increases during the period until the boundary angle α3 is reached, causing the hot water outlet temperature to rise. According to this embodiment, such a problem can be appropriately avoided.

[0059]Different from the two patterns described above, in a case where the valve device A is at the boundary (boundary angle α3) between the flow rate adjustment range mode and the temperature adjustment range mode when it is determined that output of abnormally high-temperature hot water has occurred or is likely to occur, control is performed to set the rotation angle of the motor drive shaft 8 and the valve body 7 to the angle among the first angle α1 and the second angle α2 on the side where the angle difference from the boundary angle α3 is small (S10: NO, S12). In the case of this embodiment shown in FIG. 7, the second angle α2 has a smaller angle difference from the boundary angle α3, and control is performed to set the rotation angle to this second angle α2 side. According to such operation control, it is possible to shorten the time required to set the rotation angle of the motor drive shaft 8 and the valve body 7 to either the first angle ≢1 or the second angle α2, and improve the responsiveness in preventing output of high-temperature hot water.

[0060]Unlike the aforementioned, if there is no occurrence or risk of output of abnormally high-temperature hot water, and subsequently the water inlet flow rate decreases below the minimum operating flow rate (MOQ-OFF), the burner part 2 is driven off (S5: NO, S13: YES, S14).

[0061]The disclosure is not limited to the content of the embodiment described above. The specific configuration of each part of the hot water apparatus related to the disclosure can be freely designed in various ways within the intended scope of the disclosure.

[0062]Regarding the above-described embodiment, the above-described embodiment uses the valve device A as a distribution valve installed at the cross connection point between the water inlet passage 40 and the bypass passage 42, but the disclosure is not limited thereto. For example, the valve device A can also be installed at the cross connection point (corresponding to the intermediate point Pa) between the hot water outlet passage 41 and the bypass passage 42, and can be used as a mixing valve for mixing heated hot water and bypass hot water.

[0063]As the valve device, it is possible to use other configurations, such as the valve device described in Patent Literature 2, instead of the valve device A in the above-described embodiment. Moreover, the valve device is not limited to the rotary type. For example, as described in Patent Literature 3, there are valve devices that can control flow rate by sliding a spool valve in response to the rotation angle of the drive shaft of the motor, and such valve devices can also be used.

[0064]In any case, the specific configuration of the valve device used in the disclosure is not limited, and the essential point is that the valve device has a configuration capable of sequentially executing flow rate control in a predetermined temperature adjustment range mode and flow rate control in a flow rate adjustment range mode. The specific numerical values of the first and second angles referred to in the disclosure are not limited, either.

[0065]The occurrence or risk of output of abnormally high-temperature hot water is not necessarily detected using both the temperature sensors Sc and Sd. For example, the configuration can also be made to detect the presence or absence of output of abnormally high-temperature hot water based on the temperature detected by only one of the two temperature sensors Sc and Sd.

[0066]The above-described hot water apparatus includes a burner part with a premixing system, but the burner part does not necessarily have a premixing system. Additionally, instead of a gas burner system, an oil burner system can also be used.

[0067]The hot water apparatus referred to in the disclosure is not limited to a hot water supply apparatus, but is a concept that also includes apparatuses that generate hot water for purposes other than general hot water supply or bath water supply, such as hot water apparatuses for floor heating.