Water heating system

Abstract

To provide a water heating system capable of appropriately preventing or suppressing an abnormality of high temperature hot water delivery while using a valve gear enabling flow rate control in a predetermined temperature control range mode and flow rate control range mode as hot water flow rate control means.SOLUTION: A valve gear A of a water heating system WH can sequentially execute flow rate control in a temperature control range mode in which a flow rate Qa of heated hot water gradually increases while a flow rate Qb of bypass hot water gradually decreases and flow rate control in a flow rate control range mode in which a total flow rate of hot water flowing in the valve gear A is changed so that the flow rate Qa of the heated hot water gradually decreases while the flow rate Qb of the bypass hot water is maintained to a predetermined minimum flow rate or lower, in a process in which a rotating angle of a motor drive shaft 8 for valve motion changes between a first angle α1 and a second angle α2. When generation or the possibility of generation of an abnormality of high temperature hot water deliver is detected, if the valve gear A is in the temperature control range mode, the rotating angle of the motor drive shaft 8 is set to the first angle α1, and if the valve gear is in the flow rate control range mode, the rotating angle is set to the second angle α2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hot water device such as a water heater. [Background technology]

[0002] A specific example of a water heating device is described in Patent Document 1. The hot water device described in this document is equipped with a heat exchanger capable of heating hot water using a burner, and the inlet and outlet channels connected to the inlet and outlet sides of the heat exchanger are interconnected via a bypass channel. This makes it possible to flow heated hot water heated by the heat exchanger through the outlet channel, while mixing this heated hot water with unheated bypass hot water flowing through the bypass channel. The flow rates of the heated hot water and bypass hot water can be changed using, for example, two flow control valves (a heat exchanger flow control valve and a bypass flow control valve), allowing the temperature of the mixed hot water to be set to or approach a desired target hot water temperature. In the hot water device described above, when a high-temperature hot water discharge abnormality occurs or there is a risk of hot water being discharged from the hot water outlet at a temperature higher than a predetermined temperature, this is detected by a predetermined means. Furthermore, when this is detected, both flow control valves are fully closed, preventing the flow of hot water. This appropriately prevents the occurrence of a high-temperature hot water discharge abnormality.

[0003] However, the above-mentioned conventional techniques have the following problems to be solved.

[0004] Specifically, specific examples of valve devices include the valve devices described in Patent Documents 2 and 3, which may be used in place of the two flow control valves of the hot water supply system. More specifically, the valve devices described in Patent Documents 2 and 3 are so-called three-way valves. They can be used as a mixing valve, with heated water heated by a heat exchanger and unheated bypass water flowing into the first and second ports of the valve device, and with the mixed water flowing out of the third port. In this case, as the rotation angle of the valve operation motor drive shaft changes from a predetermined first angle to a second angle, flow control in a temperature adjustment range mode, in which the flow rate of the bypass water gradually decreases while the flow rate of the heated water gradually increases, and flow control in a flow control range mode, in which the flow rate of the bypass water gradually decreases while the flow rate of the heated water is maintained at a predetermined minimum flow rate, can be sequentially performed. This configuration allows for a reduction in the total number of valve devices (flow control valves) used in the hot water supply system, simplifying the overall configuration of the hot water supply system and reducing manufacturing costs.

[0005] On the other hand, when the above-mentioned valve device is used, one possible means for preventing the discharge of high-temperature hot water when an abnormality or risk of high-temperature hot water discharge occurs in the hot water device is 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. However, if such a measure is adopted, the flow rate of heated water increases when the valve device shifts from the temperature adjustment range mode to the flow rate adjustment range mode, for example. This means that the high-temperature hot water discharge is not immediately blocked, and the flow rate ratio of heated water to bypass hot water temporarily increases during the period before the hot water discharge is blocked, which could result in the hot water temperature being higher. It is necessary to appropriately prevent this risk. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3674014 [Patent Document 2] Patent No. 5004674 [Patent Document 3] Patent No. 3812614 [Patent Document 4] Japanese Patent Application Publication No. 10-300208 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention was devised under the circumstances described above, and its objective is to provide a hot water device that can appropriately prevent or suppress abnormal high-temperature hot water discharge, while using a valve device that can control flow rate in a predetermined temperature adjustment range mode and flow rate adjustment range mode as a hot water flow rate control means. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following technical solutions.

[0009] The hot water device provided by the present invention comprises a water inlet passage and a hot water outlet passage connected respectively to the inlet side and the outlet side of a heat exchanger for heating hot water, a bypass flow path that bypasses the heat exchanger and connects the water inlet passage and the hot water outlet passage to each other, and is capable of mixing the hot water in the water inlet passage as bypass hot water with heated hot water flowing through the hot water outlet passage, a valve device that can change the flow rate of the heated hot water flowing through the hot water outlet passage and the flow rate of the bypass hot water flowing through the bypass flow path, and an abnormality detection means that can detect the occurrence or risk of a high-temperature hot water outlet abnormality in which hot water of a temperature higher than a predetermined value is discharged from the hot water outlet passage to the outside, and the valve device is configured to detect the occurrence or risk of a high-temperature hot water outlet abnormality in which hot water of a temperature higher than a predetermined value is discharged from the hot water outlet passage, and This hot water device is configured to be able to sequentially execute flow control in a temperature adjustment range mode in which the flow rate of the heated hot water gradually increases while the flow rate of the water gradually decreases, and flow control in a flow rate adjustment range mode in which the total flow rate of the hot water flowing through the valve device is changed so that the flow rate of the heated hot water gradually decreases while the flow rate of the bypass hot water is maintained below a predetermined minimum flow rate, and is characterized in that when the occurrence or risk of a high-temperature hot water discharge abnormality is detected by the abnormality detection means, if 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, while if 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.

[0010] This configuration provides the following effects. That is, when a high-temperature hot water discharge abnormality or a risk thereof occurs and the valve device is in the temperature adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to a 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 a high-temperature hot water discharge abnormality or a risk thereof occurs and 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 a second angle. In this case, the flow rate of the bypass hot water is maintained below a predetermined minimum flow rate while the flow rate of the heated hot water gradually decreases. Therefore, in either case, the flow rate of the heated hot water to the bypass hot water does not temporarily increase, and the flow rate of the heated hot water can be gradually reduced to zero or close to zero. Therefore, it is possible to appropriately prevent or suppress the discharge of abnormally high-temperature hot water without causing a malfunction such as a temporary increase in the discharged hot water temperature.

[0011] In the present invention, preferably, when the abnormality detection means detects the occurrence or risk of the high-temperature hot water discharge abnormality and the valve device is on the boundary between the temperature adjustment range mode and the flow rate adjustment range mode, control is executed to set the rotation angle of the motor drive shaft to the angle between the first and second angles which has the smaller angle difference from the boundary.

[0012] With this configuration, when a high-temperature hot water discharge abnormality or the risk of such an abnormality occurs and the valve device is on the boundary between the temperature adjustment range mode and the flow rate adjustment range mode, the time until the flow rate of heated hot water in the valve device is then reduced to zero can be minimized, which is preferable.

[0013] Other features and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic explanatory diagram showing an example of a hot water device according to the present invention. [Figure 2](a) is a side cross-sectional view of a main part showing the valve device of the hot water device of Figure 1, (b) is a side cross-sectional view of a main part at a different location from (a) of the valve device of the hot water device of Figure 1, and (c) is a bottom view of the valve device of the hot water device of Figure 1. [Figure 3] 3(a) is a side view of the main part of the valve body of the valve device shown in FIG. 2, and FIG. 3(b) is a bottom view thereof. [Figure 4] 3(a) is a plan cross-sectional view of a main part of the valve device shown in FIG. 2, (b) is a plan cross-sectional view of a main part of the valve device shown in FIG. 2 at a different location from (a), and (c) is a bottom view of the valve device corresponding to (a) and (b). [Figure 5] 4(a) is a cross-sectional view of the valve body rotated by a predetermined angle in the portion shown in FIG. 4(a), (b) is a cross-sectional view of the valve body rotated by a predetermined angle in the portion shown in FIG. 4(b), and (c) is a bottom view of the valve device corresponding to (a) and (b). [Figure 6] 5(a) is a cross-sectional view of the valve body in the state where it has been further rotated by a predetermined angle in the portion shown in FIG. 5(a), (b) is a cross-sectional view of the valve body in the state where it has been further rotated by a predetermined angle in the portion shown in FIG. 5(b), and (c) is a bottom view of the valve device corresponding to (a) and (b). [Figure 7] 3 is an explanatory diagram showing control modes of the valve device shown in FIG. 2. FIG. [Figure 8] 2 is a flowchart showing an example of an operational processing procedure executed in the hot water device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0016] The hot water device WH shown in Figure 1 is configured as a hot water supply device and includes a premixing device 3, a combustion device C (premixing combustion device), a heat exchanger 11, hot and cold water flow paths 40 to 42 described below, a valve device A, a control unit 5, and an outer case 19 that houses these and has a water inlet 43 and a hot water outlet 44.

[0017] The combustion device C is configured by combining a premixing device 3 with a fan 1 and a burner unit 2. The premixing device 3 is a device that generates a mixture (combustible mixture) of air and fuel gas. The mixture is supplied to the burner unit 2 by driving the fan 1. The burner unit 2 is configured such that a perforated plate 21 with multiple vent holes 20 is housed in a case 10, and an ignition plug 22 is attached to it. The mixture passes through the multiple vent holes 20 and is combusted below the perforated plate 21. The combustion gas generated by the burner unit 2 acts on the heat exchanger 11, and hot water passing through this heat exchanger 11 is heated. The heat exchanger 11 includes, for example, primary and secondary heat exchange sections 11A and 11B for sensible heat recovery and latent heat recovery, but is not limited to this. For example, it may also be configured with only the heat exchange section 11A for sensible heat recovery. After passing through the heat exchanger 11, the combustion gas passes through the exhaust duct portion 10a of the case 10 and is discharged to the outside as exhaust gas.

[0018] The water inlet 43 is a portion to which, for example, a water pipe is connected, and unheated hot water is supplied from the outside. The hot water outlet 44 is a portion to which the hot water heated by the heat exchanger 11 is discharged to an external hot water outlet.

[0019] The hot water flow paths of the water heater WH include a water inlet path 40, a hot water outlet path 41, and a bypass path . Here, the water inlet passage 40 is a hot and cold water flow path from the water inlet 43 to the inlet 11a of the heat exchanger 11. The water inlet passage 40 is provided with a valve device A, a flow rate sensor Sa, and a temperature sensor Sb for detecting the inlet water temperature. The water inlet passage 40 is divided into two flow paths 40a and 40b, located upstream and downstream of the valve device A, respectively.

[0020] The hot water outlet path 41 is a hot water flow path from the outlet 11b of the heat exchanger 11 to the hot water outlet 44. The hot water outlet path 41 is provided with a temperature sensor Sc for detecting the temperature on the outlet side 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 (outlet hot water temperature) downstream of the connection point of the bypass flow path 42. The combination of the temperature sensors Sc, Sd and the control unit 5 constitutes the "abnormality detection means" of the present invention, as will be described later.

[0021] Bypass flow path 42 is a hot water flow path that connects a part of valve device A corresponding to an intermediate point in water inlet path 40 with intermediate point Pa in hot water outlet path 41 so as to bypass heat exchanger 11. A portion of the hot water flowing in water inlet path 40 can pass through bypass flow path 42 and flow into intermediate point Pa in hot water outlet path 41. This allows the heated hot water in hot water outlet path 41 to be mixed with the bypass hot water flowing through bypass flow path 42 to produce temperature-adjusted mixed hot water, which can be discharged from outlet 44.

[0022] The valve device A is capable of changing the flow rate Qa of heated water flowing through the hot water outlet passage 41 and the flow rate Qb of bypass hot water flowing through the bypass passage . In Figure 2, the valve device A includes a case 6 having first to third ports P1 to P3, a valve element 7 (7A, 7B) as a rotary valve element arranged in this case 6, and a drive shaft 8 (motor drive shaft 8) of a motor M for rotating this valve element 7. The motor M is, for example, a stepping motor, and is capable of controlling the rotation angle of a drive shaft 8 connected to the valve element 7.

[0023] In this embodiment, the valve device A is configured to be used as a distribution valve that directs hot water that flows into the third port P3 to flow out to the first and second ports P1 and P2 (see also FIG. 1). The third port P3 is connected to the upstream flow path 40a of the water inlet passage 40, and unheated hot water supplied to the water inlet 43 flows into it. The second port P2 is connected to the downstream flow path 40b of the water inlet passage 40, and the hot water that flows out from this second port P2 is sent to the heat exchanger 11. The first port P1 is connected to a bypass flow path 42, and the hot water that flows out from this first port P1 flows through the bypass flow path 42 and flows into a midpoint Pa of the hot water outlet passage 41.

[0024] In FIG. 2, partition walls 61a to 63a that form openings 61 to 63 for water passage are provided in the first to third ports P1 to P3 of the case 6 at positions close to the valve body 7 inside each of the ports. On the other hand, the valve body 7 is a combination of a first valve body 7A that is approximately cylindrical and has an opening on the side of the third port P3, and a second valve body 7B that is connected to the lower part of the first valve body 7A and rotates in conjunction with the rotation of the first valve body 7A. The first valve body 7A has a peripheral wall provided with first and second openings 71, 72 extending in the circumferential direction for water passage. The second valve body 7B has a third opening 73 for communication with the third port P3, and a fan-shaped closing section 74 in a bottom view (see also Figure 3). Hot and cold water that flows into the third port P3 passes through the third opening 63 and flows into the inside of the valve body 7, then flows from the first and second openings 71, 72 through the openings 61, 62 to the first and second ports. It is possible for the signal to flow to ports P1 and P2.

[0025] As shown in FIG. 7, the valve device A can sequentially perform flow control in the temperature adjustment range mode and flow control in the flow rate adjustment range mode by changing the rotation angle of the motor drive shaft 8 and the valve element 7.

[0026] More specifically, the rotation angle of the motor drive shaft 8 and the valve element 7 can be changed from a predetermined first angle α1 to a second angle α2 beyond a predetermined boundary angle α3. The angular arrangement of the valve element 7 shown in Figure 4 corresponds to the first angle α1. Figures 5 and 6 correspond to the boundary angle α3 and the second angle α2, respectively.

[0027] When the first angle α1 shown in FIG. 4 is set, the flow rate Qb of the bypass hot water is at a maximum, and the flow rate Qa of the heated hot water flowing through the hot water outlet passage 41 is zero. That is, in this state, the third opening 63 is not blocked by the valve body 7 (second valve body 7B), and hot water and cold water 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, and a large amount of hot water and cold water flows from the first port P1 to the bypass flow path 42. The second opening 72 and the second port P2 are not connected, and hot water and cold water do not flow into the heat exchanger 11 from the second port P2.

[0028] The temperature adjustment range mode is between the first angle α1 and the boundary angle α3, and in this temperature adjustment range mode, as the rotation angle of the drive shaft 8 and the valve body 7 is increased, 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 path 41 gradually increases. That is, as the valve element 7 rotates from the state shown in FIG. 4 in the direction indicated by the arrow Da to the angle shown in FIG. 5, the communication opening area between the first opening 71 and the first port P1 gradually decreases. Therefore, the bypass hot and cold water flow rate Qb gradually decreases. As shown in FIG. 4(a), the first opening 71 extends circumferentially at an appropriate angle θ1, but its vertical width W1 (FIG. 3) narrows as it moves away from the one end 71a. In contrast, the communication area between the second opening 72 and the second port P2 gradually increases. As shown in FIG. 4(b), the second opening 72 extends circumferentially at an appropriate angle θ2, but its vertical width W2 widens as it moves away from the one end 72a. In the configuration shown in Figure 5(a), when the rotation angle of the valve body 7 (and motor drive shaft 8) is at the boundary angle α3, the bypass hot water flow rate Qb becomes zero, but instead it may be configured to be a small amount close to zero (the virtual line part in Figure 7).

[0029] The range from boundary angle α3 to second angle α2 is the flow rate adjustment range mode. In this flow rate adjustment range mode, as the rotation angle of motor drive shaft 8 and valve body 7 is increased, the total flow rate of hot water flowing through valve device A is changed so that the flow rate Qa of heated hot water flowing through hot water outlet path 41 gradually decreases while the flow rate Qb of bypass hot water is maintained below a predetermined minimum flow rate (zero or a small amount close to zero). Eventually, the flow rates Qa and Qb of bypass hot water and heated hot water both become zero. That is, when the valve element 7 reaches the angle shown in Figure 6, the water passage opening 63 is fully closed by the blocking portion 74 of the second valve element 7B, and hot water and cold 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 element 7 changing from Figure 5 to Figure 6, although the second opening 72 and the second port P2 are connected, the opening area of ​​the water passage opening 63 gradually decreases, and the flow rate of hot water and cold water into the third port P3 and the inside of the valve element 7 decreases, so the flow rate Qa decreases. 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 bypass hot water flow rate to the heated hot water flow rate at the boundary angle α3.

[0030] The control unit 5 is configured using a microcomputer and the like, and controls each part of the hot water device WH. The control unit 5 executes operational control and data processing for the valve device A, and also controls the operation of the valve device A. This control unit 5 can detect when the temperature detected by the temperature sensors Sc and Sd is abnormally high, higher than a predetermined reference temperature, and a high-temperature hot water discharge abnormality occurs, or when there is a risk of this occurring, in which hot water at a temperature higher than a predetermined temperature is discharged from the tap outlet 44 to the outside. When the control unit 5 detects this, it causes the valve device A to perform a predetermined operation to prevent or suppress the abnormally high-temperature hot water from being discharged from the tap outlet 44. However, details of this will be described later. The control unit 5 is communicatively connected to a remote control (not shown) installed in the kitchen or bathroom, and the target hot water temperature and the like can be set appropriately using this remote control.

[0031] Next, an example of the operation processing procedure of the water heating device WH will be described with reference to the flowchart of FIG. 8, and the action of the water heating device WH will also be described.

[0032] First, during normal operation when the hot water supply device WH is not supplying hot water, the motor drive shaft 8 and valve element 7 of the valve device A are controlled to be at boundary angle α3 (S1). Next, a hot water supply terminal (not shown) connected to the hot water outlet 44 of the hot water supply device WH is opened, starting the flow of hot water through the water inlet 40. When the flow rate of hot water flowing through the heat exchanger 11 reaches or exceeds a predetermined minimum operating flow rate (MOQ-ON), and this is detected based on the detection signal from the flow sensor Sa, the burner unit 2 is turned on (S2: YES, S3). This starts hot water heating using the heat exchanger 11, and hot water is dispensed from the hot water outlet 44. During this hot water supply operation, the control unit 5 controls the valve device A to perform normal operation, controlling the flow rate Qa of heated hot water and the flow rate Qb of bypass hot water, so that the temperature of the hot water dispensed from the hot water outlet 44 reaches the desired target hot water temperature (S4).

[0033] When the control unit 5 determines that a high-temperature hot water discharge abnormality has occurred or is likely to occur during the hot water supply operation, the burner unit 2 is turned off (S5: YES, S6) and the following operational control is executed. That is, if the valve device A is in the temperature adjustment range mode at that time, control is executed to set the rotation angle of the motor drive shaft 8 and the valve element 7 to the first angle α1 (S7, S8: YES, S9). During the execution of this control, as can be seen from FIG. 7, the bypass hot water flow rate Qb gradually increases while the heated hot water flow rate Qa decreases. When the first angle α1 is reached, the bypass hot water flow rate Qb is at its maximum and the heated hot water flow rate Qa is zero. Therefore, the temperature of the hot water coming out of the outlet 44 can be lowered without any temporary increase, making it possible to prevent or suppress the discharge of abnormally high temperature hot water. Unlike the above-described operational control, if the valve device A is set to the second angle α2 when it is determined that a high-temperature hot water discharge abnormality has occurred or is likely to occur, even though the valve device A is in the temperature adjustment range mode, the flow rate Qa of heated hot water will increase during the period until the boundary angle α3 is reached, and the temperature of the hot water will rise. This embodiment makes it possible to appropriately avoid such a problem.

[0034] Unlike the above, if it is determined that a high-temperature hot water discharge abnormality has occurred or is likely to occur and the valve device A is in the flow rate adjustment range mode, control is executed to set the rotation angle of the motor drive shaft 8 and the valve element 7 to the second angle α2 (S8: NO, S10: YES, S11). During the execution of this control, the bypass hot water flow rate Qb is maintained at a predetermined minimum flow rate, while the heated hot water flow rate Qa decreases. Ultimately, both the bypass hot water flow rate Qb and the heated hot water flow rate Qa become zero. Therefore, even in this case, the temperature of the hot water discharged from the outlet 44 can be lowered without any temporary increase, making it possible to prevent or suppress the discharge of abnormally high-temperature hot water. Unlike the above-mentioned operational control, if the valve device A is in the flow rate adjustment range mode when it is determined that a high-temperature hot water discharge abnormality has occurred or is likely to occur, and the control is performed to set the valve device A to the first angle α1, the flow rate Qa of the heated hot water will increase during the period until the boundary angle α3 is reached. Therefore, the outlet heated water temperature becomes high. According to this embodiment, such a problem can be appropriately avoided.

[0035] Unlike the two patterns described above, when it is determined that a high-temperature hot water discharge abnormality has occurred or is likely to occur, if the valve device A is at the boundary between the flow rate adjustment range mode and the temperature adjustment range mode (boundary angle α3), the rotational angles of the motor drive shaft 8 and the valve element 7 are controlled to be set to the angle between the first and second angles α1 and α2, whichever angle is smaller than the boundary angle α3 (S10: NO, S12). In the present embodiment shown in FIG. 7, the second angle α2 is smaller than the boundary angle α3, and the control is performed to set the rotational angles to this second angle α2. This operational control shortens the time required to set the rotational angles of the motor drive shaft 8 and the valve element 7 to either the first or second angle α1 or α2, thereby improving the responsiveness in preventing high-temperature hot water discharge.

[0036] Unlike the above, if there is no occurrence or risk of a high-temperature hot water discharge abnormality and the inlet water flow rate subsequently decreases to below the minimum operating flow rate (MOQ-OFF), the burner unit 2 is turned off (S5: NO, S13: YES, S14).

[0037] The present invention is not limited to the above-described embodiment, and the specific configuration of each part of the hot water device according to the present invention can be freely modified in various ways within the intended scope of the present invention.

[0038] In the above-described embodiment, the valve device A is used as a distribution valve provided at the cross-connection point between the water inlet passage 40 and the bypass passage 42, but the present invention is not limited to this. For example, the valve device A can be provided at the cross-connection point (corresponding to intermediate point Pa) between the water outlet passage 41 and the bypass passage 42 and used as a mixing valve that mixes heated water and bypass water.

[0039] As the valve device, instead of the valve device A of the above-described embodiment, it is possible to use a valve device with another configuration, such as that described in Patent Document 2. Furthermore, the valve device is not limited to a rotary type. As for the valve device, there is also a type that can control the flow rate by sliding a spool valve in accordance with the rotation angle of the drive shaft of the motor, as described in Patent Document 3, for example, and such a valve device can also be used. In any case, the specific configuration of the valve device used in the present invention is not important, as long as it is a valve device configured to be able to sequentially perform flow rate control in a predetermined temperature adjustment range mode and flow rate control in a flow rate adjustment range mode. The specific values ​​of the first and second angles referred to in the present invention are also not limited.

[0040] The occurrence or risk of a high-temperature hot water discharge abnormality does not necessarily have to be detected using both temperature sensors Sc and Sd. For example, the presence or absence of a high-temperature hot water discharge abnormality can be determined based on the temperature detected by only one of the two temperature sensors Sc and Sd. Although the water heating device described above is equipped with a premixing burner unit, the burner unit does not have to be of the premixing type. Also, an oil burner type may be used instead of a gas burner type. The hot water device referred to in the present invention is not limited to a hot water supply device, but also includes a concept that includes a device that generates hot water for purposes other than general hot water supply or hot water supply for baths, such as a hot water device for floor heating. [Explanation of symbols]

[0041] WH water heater A valve gear C. Combustion device Qa Flow rate of heated water Qb Bypass hot and cold water flow rate α1,α2 First and second angles Sc, Sd temperature sensor (anomaly detection means) 11 Heat exchanger 40 Inlet Channel 41 Hot water outlet 42 Bypass flow path 43 Water Inlet 44 Tap 5. Control unit (abnormality detection means) 8 Motor drive shaft

Claims

1. a water inlet channel and a hot water outlet channel connected to the inlet side and the outlet side, respectively, of a heat exchanger for heating hot water; a bypass flow path that bypasses the heat exchanger and connects the water inlet and the hot water outlet, and allows the hot water in the water inlet to be mixed with the heated hot water flowing through the hot water outlet as bypass water; a valve device capable of changing the flow rate of the heated water flowing through the hot water outlet passage and the flow rate of the bypass hot water flowing through the bypass passage; An abnormality detection means capable of detecting the occurrence or possibility of a high-temperature hot water discharge abnormality in which hot water of a predetermined temperature or higher is discharged from the hot water discharge passage to the outside; It is equipped with The valve device is configured to be capable of sequentially executing flow rate control in a temperature adjustment range mode in which the flow rate of the heated hot water gradually increases while the flow rate of the bypass hot water gradually decreases, and flow rate control in a flow rate adjustment range mode in which the total flow rate of the hot water flowing into the valve device is changed 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, during the process in which the rotation angle of the motor drive shaft for valve operation changes between a predetermined first angle and a second angle, When the occurrence or possibility of the high-temperature hot water discharge abnormality is detected by the abnormality detection means, if 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, A hot water device characterized in that, when 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.

2. The hot water device according to claim 1, When the occurrence or possibility of the high-temperature hot water discharge abnormality is detected by the abnormality detection means, if the valve device is at the boundary between the temperature adjustment range mode and the flow rate adjustment range mode, A water heating device configured to execute control to set the rotation angle of the motor drive shaft to one of the first and second angles, whichever angle has a smaller angle difference from the boundary.

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