Heating and hot water supply apparatus

Abstract

To detect abnormality of a circulation switching means even if the circulation switching means of a heating hot water supply device is not provided with a limit switch interlocked with a switching state.SOLUTION: This water heater has an external circulation passage for circulating a heating medium to a heating terminal 20, an internal circulation passage including a common part with the external circulation passage and circulating the heating medium to a hot water supply heat exchanger 28, a first temperature sensor 25 for detecting a temperature of the heating medium heated by the common part, and a second temperature sensor 35 for detecting a temperature of hot water heated by the hot water supply heat exchanger. A circulation switching means 29 capable of switching whether the heating medium is circulated in the external circulation passage or the internal circulation passage is controlled by a switching control means 40. Assumed detection values of the second temperature sensors assumed when the circulation-switching means is normal are previously stored in a storage means 40a in association with the switching states of the circulation-switching means, and an abnormality detection means 40 detects the abnormality of the circulation-switching means on the basis of a difference between the assumed detection value corresponding to the switching state instructed by the switching control means and the detection value of the second temperature sensors.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heating and hot water supply device that can perform a heating operation in which a heat medium is circulated through a heating terminal to provide heating, and a hot water supply operation in which a shared heat medium is circulated through a hot water heat exchanger and water supplied to the hot water heat exchanger is heated by heat exchange with the heat medium to produce hot water. [Background technology]

[0002] A heating and hot water supply system is known that can perform a heating operation in which a heat medium heated by a heating means such as a burner is circulated to a heating terminal using a circulation pump, and can also perform a hot water supply operation in which a shared heat medium is circulated to a hot water heat exchanger and water supplied to the hot water heat exchanger is heated by heat exchange with the heat medium to produce hot water. Such a heating and hot water supply system has an external circulation path that circulates the heat medium to the heating terminal and an internal circulation path that includes a common section with the external circulation path and circulates the heat medium to the hot water heat exchanger. A circulation pump is provided in the common section, and the heat medium is heated by the heating means in the common section. Furthermore, a circulation switching means such as a three-way valve can be used to switch between a heating circulation state in which the heat medium is circulated in the external circulation path and a hot water circulation state in which the heat medium is circulated in the internal circulation path. Furthermore, a temperature sensor is provided in the common section to detect the temperature of the heat medium heated by the heating means, and heating of the heating means is controlled based on the temperature detected by the temperature sensor.

[0003] In such a heating and hot water supply system, if an abnormality (failure) occurs in the three-way valve, for example, if the three-way valve does not switch to the heating circulation state during heating operation and remains in the hot water circulation state, the hot water in the hot water heat exchanger will be heated, making it more likely that hot water will be dispensed at a higher temperature the next time hot water is dispensed. Conversely, if the three-way valve does not switch to the hot water circulation state during hot water supply operation and remains in the heating circulation state, the temperature of the dispensed hot water will not rise, and hot water will not be dispensed at the set temperature, which will reduce user comfort. Therefore, it has been proposed to provide the three-way valve itself with a limit switch that is linked to the switching state (position) of the valve disc, and to detect abnormalities in the three-way valve based on this limit switch (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-53750 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in heating and hot water supply devices that use a circulation switching means (three-way valve) that does not have a limit switch for purposes such as reducing product costs, there is a problem in that abnormalities in the circulation switching means cannot be detected based on the limit switch, which can lead to malfunctions that impair user comfort, as described above.

[0006] This invention has been made in response to the above-mentioned problems of the conventional technology, and aims to provide technology that can detect abnormalities in the circulation switching means (three-way valve) in a heating and hot water supply device even if the circulation switching means is not equipped with a limit switch that is linked to the switching state. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the heating and hot water supply device of the present invention employs the following configuration: <First aspect> A heating and hot water supply device capable of performing a heating operation in which a heat medium is circulated to a heating terminal for heating, and a hot water supply operation in which the shared heat medium is circulated to a hot water heat exchanger and water supplied to the hot water heat exchanger is heated by heat exchange with the heat medium to produce hot water, an external circulation path for circulating the heat medium to the heating terminal; an internal circulation path that includes a common portion with the external circulation path and circulates the heat medium to the hot water heat exchanger; a circulation pump that sends the heat medium in a predetermined direction in the common portion; a heating means capable of heating the heat medium in the common portion; a first temperature sensor provided downstream of the heating means in the common portion and detecting the temperature of the heat medium heated by the heating means; a circulation switching means for switching between a heating circulation state in which the heat medium is circulated in the external circulation path and a hot water circulation state in which the heat medium is circulated in the internal circulation path; a switching control means for controlling the switching of the circulation switching means; a second temperature sensor for detecting the temperature of the hot water heated by the hot water heat exchanger; a storage means for storing in advance an assumed detected value, which is a detected value of the second temperature sensor assumed when the circulation switching means is normal, in association with a switching state of the circulation switching means; an abnormality detection means for detecting an abnormality in the circulation switching means based on a difference between the assumed detection value corresponding to the switching state of the circulation switching means instructed by the switching control means and the detection value of the second temperature sensor; The present invention is characterized by comprising:

[0008] In the heating and hot water supply device of the first aspect, if the circulation switching means is normal, the expected detection value corresponding to the switching state (heating circulation state or hot water circulation state) instructed by the switching control means should be reproduced as the detection value of the second temperature sensor, so even if the circulation switching means does not have a limit switch or the like linked to the switching state, an abnormality in the circulation switching means can be detected based on the detection value of the second temperature sensor being different from the expected detection value. Furthermore, since this second temperature sensor is generally installed to detect the temperature of hot water during hot water supply, it is possible to detect an abnormality in the circulation switching means while reducing manufacturing costs by reusing the existing second temperature sensor without adding a new part.

[0009] <Second aspect> In the heating and hot water supply device of the first aspect, When the heating circulation state is instructed by the switching control means, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that the assumed detection value corresponding to the heating circulation state is less than a predetermined threshold value while the detection value of the second temperature sensor reaches the threshold value. It is characterized by:

[0010] In such a second aspect of the heating and hot water supply device, if the circulation switching means that has been instructed to switch to the heating circulation state is normal, the heat medium will not circulate in the internal circulation path (hot water heat exchanger) and the detection value of the second temperature sensor will not reach the threshold value.Contrary to this, an abnormality in the circulation switching means can be detected based on the detection value of the second temperature sensor rising to the threshold value.

[0011] <Third aspect> In the heating and hot water supply device of the second aspect, The threshold value is set differently depending on an initial detection value, which is a detection value of the second temperature sensor at the time when the heating circulation state is instructed by the switching control means, and the higher the initial detection value, the higher the threshold value. It is characterized by:

[0012] In the heating and hot water supply device of the third aspect, for example, if the hot water supply operation was being performed (the heat medium was circulating in the internal circulation path) before the heating circulation state was instructed by the switching control means, the initial detection value of the second temperature sensor may already be high at the time the heating circulation state was instructed. Even in this case, if there is an abnormality in the circulation switching means, the detection value of the second temperature sensor may rise from the initial detection value, so by raising the threshold value according to the level of the initial detection value, it is possible to detect an abnormality in the circulation switching means based on the detection value of the second temperature sensor reaching the threshold value, while suppressing erroneous detection.

[0013] <Fourth aspect> In the heating and hot water supply device of any one of the first to third aspects, The storage means stores the change in the assumed detection value over time, When the detected value of the second temperature sensor at the time when the heating circulation state is instructed by the switching control means is less than a specified value, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that the rising gradient, which is the change over time of the assumed detected value corresponding to the heating circulation state within a specified period, is less than the specified rising gradient, while the detected value of the second temperature sensor rises to or exceeds the specified rising gradient within the specified period. It is characterized by:

[0014] In the heating and hot water supply device of the fourth aspect, assuming that the detection value of the second temperature sensor is lower than a specified value when the heating circulation state is instructed by the switching control means, if there is an abnormality in the circulation switching means (if the heat medium is circulating in the hot water heat exchanger), the detection value of the second temperature sensor will rise more rapidly than when it is normal, so that an abnormality in the circulation switching means can be detected based on whether the rising gradient of the detection value of the second temperature sensor is equal to or greater than a specified rising gradient within a specified period of time.By detecting an abnormality in the circulation switching means based on the rising gradient of the detection value of the second temperature sensor in this way, it is possible to quickly detect an abnormality in the circulation switching means before the detection value of the second temperature sensor rises to a specified threshold.

[0015] <Fifth aspect> In any one of the heating and hot water supply apparatuses of the first to fourth aspects, When the hot water supply circulation state is instructed by the switching control means, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that, in a state in which the detected value of the first temperature sensor reaches a reference value, the assumed detected value corresponding to the hot water supply circulation state after the standby time has elapsed is equal to or greater than a determination value, while the detected value of the second temperature sensor after the standby time has elapsed is less than the determination value. It is characterized by:

[0016] In the heating and hot water supply device of the fifth aspect, if the first temperature sensor detects a reference value, it is assumed that the heat medium heated by the heating means is circulating due to the operation of the circulation pump. In this state, if the circulation switching means instructed to switch to the hot water circulation state is normal, the heat medium circulates in the internal circulation path (hot water heat exchanger), causing the detection value of the second temperature sensor to rise and reach the determination value. Therefore, an abnormality in the circulation switching means can be detected based on the fact that the detection value of the second temperature sensor does not rise to the determination value. Furthermore, when repeatedly switching between hot water supply operation and heating operation, heat from the previous hot water supply operation may remain in the hot water heat exchanger, and the detection value of the second temperature sensor may already be high when the hot water circulation state is instructed. In this case, if an abnormality occurs in the circulation switching means, the system does not switch to the hot water circulation state and the heat medium does not circulate in the internal circulation path (hot water heat exchanger), and the detection value of the second temperature sensor will fall below the determination value before the standby time has elapsed, making it possible to detect an abnormality in the circulation switching means. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an explanatory diagram showing the configuration of a heating and hot water supply device 1 of the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a three-way valve 29 of the present embodiment. [Figure 3] 4 is a flowchart of a three-way valve abnormality detection process executed by a controller 40 of the present embodiment. [Figure 4] 10 is a flowchart of a heating abnormality detection process according to the present embodiment, which is executed in the three-way valve abnormality detection process. [Figure 5] 10 is a flowchart of a hot water supply abnormality detection process according to the present embodiment, which is executed in the three-way valve abnormality detection process. [Figure 6] 10 is a flowchart of a modified heating abnormality detection process executed in the three-way valve abnormality detection process. [Figure 7] As an example, this is a graph comparing the rising gradient of the detected value of the heat exchanger outlet hot water temperature sensor 35 when the three-way valve 29 is normal and when it is abnormal. DETAILED DESCRIPTION OF THE INVENTION

[0018] Figure 1 is an explanatory diagram showing the configuration of a heating and hot water supply system 1 of this embodiment. As shown in the figure, the heating and hot water supply system 1 is enclosed in a housing 2 and equipped with a combustion unit 4 incorporating a burner 3 that burns a mixture of fuel gas and combustion air. A combustion fan 5 is connected to the combustion unit 4, and the mixture gas is fed by this combustion fan 5.

[0019] A confluence 6 is provided on the intake side of the combustion fan 5, where an air supply passage 7 that supplies combustion air and a gas supply passage 8 that supplies fuel gas converge. The gas supply passage 8 is provided with an on-off valve (not shown) that opens and closes the gas supply passage 8, and a zero governor 9 that reduces the pressure of the fuel gas pumped from upstream to atmospheric pressure. A control valve is built into the confluence 6, making it possible to adjust the ratio of combustion air and fuel gas flowing into the combustion fan 5. When the combustion fan 5 is driven, the air inside the housing 2 and the fuel gas downstream of the zero governor 9 on the gas supply passage 8 are drawn into the combustion fan 5 at a predetermined ratio through the confluence 6, and the mixed gas is sent to the combustion unit 4.

[0020] In the combustion unit 4, the mixed gas is combusted in the built-in burner 3. In the illustrated example, the mixed gas is ejected downward from the burner 3, forming a downward flame, and the combustion exhaust is sent downward. The combustion fan 5 is electrically connected to a controller 40 that controls the overall operation of the heating and hot water supply device 1, and the controller 40 controls the amount of combustion in the burner 3 by changing the rotation speed of the combustion fan 5 according to the amount of heat required.

[0021] The combustion unit 4 is also provided with an ignition plug 11 that generates a spark in the burner 3 by discharging a high voltage, a flame rod 12 that detects the flame (ignition) of the burner 3, and a check valve 13 that prevents backflow from the combustion unit 4 to the combustion fan 5. The ignition plug 11 and the flame rod 12 are electrically connected to the controller 40.

[0022] A first heat exchanger 15 is provided below the burner 3, and a second heat exchanger 16 is provided below the first heat exchanger 15. The combustion exhaust gas generated by combustion in the burner 3 is sent downward and passes through the first heat exchanger 15 and the second heat exchanger 16 in that order. At this time, the first heat exchanger 15 recovers sensible heat from the combustion exhaust gas, and the second heat exchanger 16 recovers latent heat from the combustion exhaust gas.

[0023] The combustion exhaust gas that has passed through the first heat exchanger 15 and the second heat exchanger 16 passes through an exhaust duct 17 and is discharged from an exhaust port 18 that protrudes from the top of the housing 2. In the illustrated example, an air intake port 19 is provided at the top of the housing 2, and air taken into the housing 2 from the air intake port 19 is supplied to the junction 6 through the air supply path 7.

[0024] The upstream side of the first heat exchanger 15 is connected to the downstream side of the second heat exchanger 16. The downstream side of the first heat exchanger 15 is connected to the upstream side of a panel radiator 20 serving as a heating terminal via a feed passage 21, and the upstream side of the second heat exchanger 16 is connected to the downstream side of the panel radiator 20 via a return passage 22. The return passage 22 is provided with a circulation pump 23 that sends the heat medium toward the second heat exchanger 16 and a return temperature sensor 24 that detects the temperature of the heat medium flowing into the second heat exchanger 16 (hereinafter referred to as the return temperature). The circulation pump 23 and the return temperature sensor 24 are electrically connected to the controller 40. The circulation pump 23 in this embodiment is configured to send the heat medium while maintaining a constant rotation speed.

[0025] The heat transfer medium sent to the second heat exchanger 16 by the operation of the circulation pump 23 is preheated in the second heat exchanger 16 by latent heat recovered from the combustion exhaust gas of the burner 3, and then sent to the first heat exchanger 15. In the first heat exchanger 15, the heat transfer medium is heated by sensible heat recovered from the combustion exhaust gas of the burner 3, and the high-temperature heat transfer medium is supplied to the panel radiator 20 through the supply passage 21. A supply temperature sensor 25 is provided in the supply passage 21 connected downstream of the first heat exchanger 15 to detect the temperature of the heat transfer medium flowing out from the first heat exchanger 15 (hereinafter referred to as the supply temperature), and the supply temperature sensor 25 is electrically connected to the controller 40. The controller 40 determines the required amount of heat based on the detection value of the supply temperature sensor 25 and controls combustion in the burner 3. The supply temperature sensor 25 in this embodiment corresponds to the "first temperature sensor" of the present invention. The burner 3, the first heat exchanger 15, and the second heat exchanger 16 in this embodiment correspond to the "heating means" of the present invention.

[0026] The panel radiator 20 has pipes 20a that snake inside a metal panel, and heat transfer medium radiates heat as it passes through the pipes 20a, warming the surrounding area. After passing through the panel radiator 20, the heat transfer medium returns to the circulation pump 23 through a return passage 22 and is then sent to the second heat exchanger 16 again for circulation. Note that although the heating and hot water supply device 1 of this embodiment uses hot water as the heat transfer medium, the heat transfer medium is not limited to hot water, and antifreeze such as ethylene glycol, silicone oil, etc. may also be used.

[0027] Furthermore, a branch passage 27 branches off from the supply passage 21 downstream of the supply temperature sensor 25 and is connected to the return passage 22 upstream of the circulation pump 23. A hot water heat exchanger 28 is provided in this branch passage 27. A three-way valve 29 is provided at the connection between the branch passage 27 and the return passage 22, and the three-way valve 29 is electrically connected to a controller 40. The configuration of the three-way valve 29 will be described later using a separate drawing. The three-way valve 29 can switch between circulating the heat medium flowing out of the first heat exchanger 15 through a route passing through the panel radiator 20 (heating terminal) (hereinafter referred to as an external circulation route) or through a route passing through the hot water heat exchanger 28 (hereinafter referred to as an internal circulation route). The three-way valve 29 in this embodiment corresponds to the "circulation switching means" of the present invention, and the controller 40 in this embodiment has a function corresponding to the "switching control means" of the present invention. In addition, in this embodiment, the section from the downstream side of the connection point with the branch passage 27 in the return passage 22 to the upstream side of the connection point with the branch passage 27 in the outward passage 21 corresponds to the ``common section'' of the present invention.

[0028] The hot water heat exchanger 28 is a liquid-liquid heat exchanger, and is connected to a water supply passage 30 and a hot water outlet passage 31. The clean water supplied to the hot water heat exchanger 28 through the water supply passage 30 is heated by heat exchange with a heat medium in the hot water heat exchanger 28, and the hot water flows out into the hot water outlet passage 31. The water supply passage 30 is provided with a water volume sensor 32 that measures the flow rate of the clean water flowing into the heating and hot water supply device 1, a water volume servo 33 that adjusts the clean water flow rate, and a water supply temperature sensor 34 that detects the temperature of the clean water. The hot water outlet passage 31 is provided with a heat exchanger outlet hot water temperature sensor 35 that detects the temperature of the hot water immediately after it flows out of the hot water heat exchanger 28. The water volume sensor 32, the water volume servo 33, the water supply temperature sensor 34, and the heat exchanger outlet hot water temperature sensor 35 are electrically connected to the controller 40. The heat exchanger outlet hot water temperature sensor 35 in this embodiment corresponds to the "second temperature sensor" of the present invention.

[0029] In the heating and hot water supply apparatus 1 of this embodiment, a bypass passage 36 connects the downstream side of the water supply passage 30 relative to the water supply temperature sensor 34 and the downstream side of the hot water outlet passage 31 relative to the heat exchanger hot water outlet temperature sensor 35. A portion of the clean water flowing into the heating and hot water supply apparatus 1 can pass through the bypass passage 36 without being supplied to the hot water heat exchanger 28, and the remainder is supplied to the hot water heat exchanger 28. The hot water heated in the hot water heat exchanger 28 is mixed with the clean water that has passed through the bypass passage 36 and flows out of the heating and hot water supply apparatus 1. A bypass servo 37 is provided at the connection between the bypass passage 36 and the hot water outlet passage 31, and the bypass servo 37 is electrically connected to the controller 40. The mixing ratio of the hot water heated in the hot water heat exchanger 28 and the clean water that has passed through the bypass passage 36 can be changed by the bypass servo 37.

[0030] An outlet hot water temperature sensor 38 that detects the temperature of the hot water flowing out from the heating and hot water supply apparatus 1 is provided downstream of the bypass servo 37 in the hot water outlet passage 31, and the outlet hot water temperature sensor 38 is connected to the controller 40. As described above, when part of the clean water from the water supply passage 30 passes through the bypass passage 36 without passing through the hot water heat exchanger 28 and joins the hot water outlet passage 31, the detected value of the outlet hot water temperature sensor 38 will naturally be lower than the detected value of the heat exchanger outlet hot water temperature sensor 35, and by adjusting the mixing ratio with the bypass servo 37, it is possible to suppress temperature fluctuations of the hot water flowing out from the heating and hot water supply apparatus 1.

[0031] Furthermore, a hot water supply remote control 41 and a heating remote control 42 are connected to the controller 40. By operating the hot water supply remote control 41, the user can switch the hot water supply operation between ON and OFF and set the hot water supply temperature. Similarly, by operating the heating remote control 42, the user can instruct the heating operation to start or stop and set the heating temperature. Furthermore, the controller 40 is equipped with a storage means 40a, and various information related to the heating and hot water supply apparatus 1 can be stored in the storage means 40a, as described below.

[0032] 2 is a cross-sectional view showing the configuration of the three-way valve 29 of this embodiment. As shown in the figure, a valve chamber 50 that communicates in three directions is formed inside the three-way valve 29. In the example shown, the branch passage 27 is connected to the left of the valve chamber 50, the return passage 22 on the panel radiator 20 side of its connection with the branch passage 27 (hereinafter referred to as the terminal-side return passage 22a) is connected to the right, and the return passage 22 on the second heat exchanger 16 side of its connection with the branch passage 27 (hereinafter referred to as the heat exchanger-side return passage 22b) is connected above.

[0033] Also housed within valve chamber 50 are a hot-water-side valve element 51 that opens and closes branch passage 27, and a heating-side valve element 52 that opens and closes terminal-side return passage 22a, and these hot-water-side valve element 51 and heating-side valve element 52 are attached facing opposite to each other to a moving shaft 53 that can move back and forth in the left and right direction. Moving shaft 53 is driven by a drive mechanism 54, and in this embodiment, drive mechanism 54 converts the rotation of a built-in stepping motor into axial (left and right) movement of moving shaft 53.

[0034] 2(a) shows a state in which the moving shaft 53 has moved leftward, causing the hot water supply side valve element 51 to close the branch passage 27 and the heating side valve element 52 to open the terminal side return passage 22a. At this time, the heat medium flowing out of the first heat exchanger 15 due to the operation of the circulation pump 23 circulates through the panel radiator 20 (external circulation path) without being distributed to the hot water supply heat exchanger 28, resulting in a heating circulation state.

[0035] On the other hand, when the moving shaft 53 is moved to the right by the driving of the drive mechanism 54, the heating-side valve element 52 closes the terminal-side return passage 22a, and the hot-water-side valve element 51 opens the branch passage 27, as shown in Figure 2(b). At this time, the heat medium flowing out of the first heat exchanger 15 due to the operation of the circulation pump 23 circulates through the hot-water heat exchanger 28 (internal circulation path) without being distributed to the panel radiator 20, resulting in a hot-water circulation state.

[0036] Furthermore, although not shown, by stopping the moving shaft 53 midway between the heating circulation state of Figure 2(a) and the hot water circulation state of Figure 2(b), both the branch passage 27 and the terminal side return passage 22a are opened, making it possible to simultaneously circulate the heat medium in both the panel radiator 20 (external circulation path) and the hot water heat exchanger 28 (internal circulation path).

[0037] In this type of heating and hot water supply system 1, if an abnormality (failure) occurs in the three-way valve 29, user comfort may be compromised. For example, if the three-way valve 29 remains in the hot water circulation state during heating operation without switching to the heating circulation state due to a sticking or foreign object being trapped in the heating-side valve element 52 that closes the terminal-side return passage 22a in the hot water circulation state, the hot water in the hot water heat exchanger 28 will be heated. In particular, in the heating and hot water supply system 1 of this embodiment, which uses a panel radiator 20 as the heating terminal, the heating medium temperature during heating operation may be set higher than the heating medium temperature during hot water supply operation, making it more likely that hot water will be dispensed at a higher temperature the next time hot water is dispensed. Conversely, if the three-way valve 29 remains in the heating circulation state without switching to the hot water circulation state during hot water supply operation, the outlet hot water temperature will not rise, and hot water will not be dispensed at the set temperature, thereby compromising user comfort. Therefore, in the heating and hot water supply system 1 of this embodiment, in order to detect an abnormality in the three-way valve 29, the controller 40 executes the following three-way valve abnormality detection process. The controller 40 of this embodiment has a function corresponding to the "abnormality detecting means" of the present invention.

[0038] 3 is a flowchart of the three-way valve abnormality detection process executed by the controller 40 of this embodiment. As shown in the figure, when the three-way valve abnormality detection process starts, first, it is determined whether or not the three-way valve 29 has been instructed to switch to the heating circulation state (STEP 1). The controller 40 executes the instruction to switch to the heating circulation state based on an operation on the heating remote control 42. Then, if the three-way valve 29 has been instructed to switch to the heating circulation state (STEP 1: yes), the following heating abnormality detection process is executed (STEP 2). After the heating abnormality detection process is executed, the process returns to STEP 1.

[0039] 4 is a flowchart of the heating abnormality detection process executed in the three-way valve abnormality detection process of this embodiment. The heating abnormality detection process begins with obtaining an initial detection value of the heat exchanger outlet hot water temperature sensor 35 (STEP 10). As described above, the heat exchanger outlet hot water temperature sensor 35 can detect the temperature of hot water immediately after it leaves the hot water heat exchanger 28. The detection value of the heat exchanger outlet hot water temperature sensor 35 at the time the heating abnormality detection process is started based on an instruction to switch to the heating circulation state is obtained as the initial detection value.

[0040] Next, a threshold value for the detection value of the heat exchanger outlet hot water temperature sensor 35 is selected based on the acquired initial detection value (STEP 11). This threshold value is set to a value higher than the initial detection value and that the detection value of the heat exchanger outlet hot water temperature sensor 35 will not exceed when the three-way valve 29 is in the heating circulation state. The threshold value is pre-stored in the storage means 40a of the controller 40 in association with the heating circulation state of the three-way valve 29. If the three-way valve 29 operates normally and is switched to the heating circulation state (see FIG. 2(a)), the heat medium does not circulate through the hot water heat exchanger 28 (internal circulation path), and the expected detection value of the heat exchanger outlet hot water temperature sensor 35 (hereinafter, the expected detection value) is less than the threshold value. However, if the hot water supply operation was being performed (the heat medium was circulating through the hot water heat exchanger 28) before the three-way valve 29 was instructed to switch to the heating circulation state, the initial detection value of the heat exchanger outlet hot water temperature sensor 35 may already be high. Therefore, a different threshold value is set depending on the initial detection value. For example, if the initial detection value is less than 30° C., the threshold is set to 40° C., if the initial detection value is equal to or greater than 30° C. but less than 40° C., the threshold is set to 50° C., if the initial detection value is equal to or greater than 40° C., the threshold is set to 60° C., and the higher the initial detection value, the higher the threshold. Note that in this embodiment, the correspondence relationship between the initial detection value and the threshold is divided into three stages, but the correspondence relationship between the initial detection value and the threshold is not limited to three stages and may be further divided and set.

[0041] After selecting the threshold value based on the initial detection value, the controller 10 then determines whether the detection value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the threshold value (STEP 12). If the detection value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the threshold value (STEP 12: yes), the heat medium circulates through the hot water heat exchanger 28 (internal circulation path) and heats the hot water in the hot water heat exchanger 28. This detects an abnormality in the three-way valve 29 (STEP 13), and issues a warning of the abnormality in the three-way valve 29 (STEP 14). In this embodiment, the warning of the abnormality is displayed on a display (not shown) of the hot water supply remote control 41 or the heating remote control 42. The warning may be issued by audio output from a speaker (not shown) built into the hot water supply remote control 41 or the heating remote control 42. In addition to the warning of the abnormality, the burner 3 may be stopped, or the water flow servo 33 may be throttled to prohibit (limit) hot water supply. Thereafter, the heating abnormality detection process of FIG. 4 and the three-way valve abnormality detection process of FIG. 3 are terminated.

[0042] On the other hand, if the detected value of heat exchanger outlet hot water temperature sensor 35 is below the threshold (STEP 12: no), it is determined whether the monitoring period has ended (STEP 15). In this embodiment, the monitoring period is set to the period from when three-way valve 29 is instructed to switch to the heating circulation mode until a predetermined time (e.g., 3 minutes) has elapsed. If the monitoring period has not yet ended (STEP 15: no), the process returns to STEP 12, where it is repeatedly determined whether the detected value of heat exchanger outlet hot water temperature sensor 35 has exceeded the threshold. If the detected value of heat exchanger outlet hot water temperature sensor 35 does not exceed the threshold and the monitoring period ends (STEP 15: yes), three-way valve 29 is determined to be normal, and the heating abnormality detection process of FIG. 4 is terminated, and the process returns to the three-way valve abnormality detection process of FIG. 3.

[0043] The above describes the process executed when the three-way valve 29 is instructed to switch to the heating circulation state (STEP 1: yes) in STEP 1 of the three-way valve abnormality detection process. On the other hand, if the three-way valve 29 has not been instructed to switch to the heating circulation state (STEP 1: no), it is next determined whether the three-way valve 29 has been instructed to switch to the hot water circulation state (STEP 3). Note that the controller 40 is configured to execute the command to switch to the hot water circulation state based on an operation on the hot water supply remote control 41. Then, if the three-way valve 29 has not been instructed to switch to the hot water circulation state (STEP 3: no), the process returns to STEP 1.

[0044] On the other hand, if the three-way valve 29 is instructed to switch to the hot water supply circulation state (STEP 3: yes), the following hot water supply abnormality detection process is executed (STEP 4). After the hot water supply abnormality detection process is executed, the process returns to STEP 1.

[0045] 5 is a flowchart of the hot water supply abnormality detection process of this embodiment, which is executed during the three-way valve abnormality detection process. In the hot water supply abnormality detection process, first, it is determined whether a predetermined standby time (e.g., 5 minutes) has elapsed since the three-way valve 29 was instructed to switch to the hot water supply circulation state (STEP 20). If the standby time has not yet elapsed (STEP 20: no), the process returns to the beginning of the hot water supply abnormality detection process, and the determination in STEP 20 is repeated.

[0046] Thereafter, if the standby time has elapsed (STEP 20: yes), it is determined whether the detection value of forward temperature sensor 25 is equal to or greater than a reference value (STEP 21). As described above, forward temperature sensor 25 is capable of detecting the temperature (forward temperature) of the heat medium flowing out of first heat exchanger 15, and the minimum detection value of forward temperature sensor 25 expected when operation of circulation pump 23 and combustion in burner 3 are normal is set in advance as the reference value. Note that the reference value may be stored in advance in storage means 40a of controller 40 and may be changeable according to the hot water temperature set by hot water supply remote control 41, or the reference value may be higher as the hot water temperature setting is higher.

[0047] If the detection value of the supply temperature sensor 25 is less than the reference value (STEP 21: no), it is determined that there is an abnormality in the combustion in the circulation pump 23 or the burner 3 (STEP 22), and a notification of the abnormality in the combustion in the circulation pump 23 or the burner 3 is issued (STEP 23). In this embodiment, the abnormality is notified by displaying a message on the display unit of the hot water supply remote control 41 or the heating remote control 42. However, it may also be notified by audio output from a built-in speaker of the hot water supply remote control 41 or the heating remote control 42. Furthermore, in addition to notifying the abnormality, combustion in the burner 3 may be stopped. Then, the hot water supply abnormality detection process of FIG. 5 and the three-way valve abnormality detection process of FIG. 3 are terminated. Note that if the detection value of the supply temperature sensor 25 is less than the reference value, it is determined that there is no risk of hot water being dispensed at a high temperature, and the hot water supply may be limited by throttling the water volume servo 33 without directly issuing a notification of the abnormality.

[0048] On the other hand, if the detection value of the supply temperature sensor 25 is equal to or greater than the reference value (STEP 21: yes), it is determined that the operation of the circulation pump 23 and the combustion in the burner 3 are normal. Next, it is determined whether the detection value of the heat exchanger outlet hot water temperature sensor 35 is less than a judgment value (STEP 24). This judgment value is set to the lowest value that can be detected by the heat exchanger outlet hot water temperature sensor 35 when the three-way valve 29 is in the hot water circulation state. The judgment value is pre-stored in the storage means 40a of the controller 40 in association with the hot water circulation state of the three-way valve 29. If the three-way valve 29 is operating normally and switched to the hot water circulation state (see FIG. 2(b)), the heat medium circulates through the hot water heat exchanger 28 (internal circulation path) to heat the hot water in the hot water heat exchanger 28. Therefore, the expected detection value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the judgment value. Note that different judgment values ​​may be set depending on the hot water temperature set by the hot water supply remote control 41, and the judgment value may be higher as the hot water temperature setting increases.

[0049] If the detected value of the heat exchanger outlet hot water temperature sensor 35 is less than the reference value (step 24: yes), even though the heat medium at a temperature equal to or higher than the reference value is flowing out of the first heat exchanger 15, the heat medium is not circulating in the hot water heat exchanger 28 (internal circulation path), and the hot water in the hot water heat exchanger 28 is not being heated. Therefore, an abnormality in the three-way valve 29 is detected (step 25), and the abnormality in the three-way valve 29 is notified (step 26). The hot water supply abnormality detection process of FIG. 5 and the three-way valve abnormality detection process of FIG. 3 are then terminated. In this embodiment, the abnormality is notified by displaying a message on the display unit of the hot water supply remote control 41 or the heating remote control 42. However, it may also be notified by audio output from a speaker built into the hot water supply remote control 41 or the heating remote control 42. Although the temperature of the hot water in the hot water heat exchanger 28 does not rise to the reference value, there is no risk of the hot water being discharged at a high temperature. Therefore, the abnormality may not be directly notified, and the water volume servo 33 may be throttled to limit the hot water supply. In addition, the detection of an abnormality in the three-way valve 29 may be stored in the memory means 40a, and the detection of an abnormality in the three-way valve 29 may be displayed on the display unit of the hot water supply remote control 41 or the heating remote control 42 during maintenance of the heating and hot water supply device 1.

[0050] On the other hand, if the detection value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the judgment value (STEP 24: no), the three-way valve 29 is judged to be normal, and the hot water supply abnormality detection process of Figure 5 is terminated and the process returns to the three-way valve abnormality detection process of Figure 3.

[0051] As described above, in the heating and hot water supply device 1 of this embodiment, in addition to the supply temperature sensor 25 that detects the temperature (supply temperature) of the heat medium flowing out of the first heat exchanger 15, a heat exchanger outlet hot water temperature sensor 35 that detects the temperature of the hot water immediately after flowing out of the hot water heat exchanger 28 is provided, and the detected value (assumed detected value) of the heat exchanger outlet hot water temperature sensor 35 that is expected when the three-way valve 29 is normal is stored in advance in the storage means 40a of the controller 40 in association with the switching state of the three-way valve 29. Then, an abnormality in the three-way valve 29 is detected based on the difference between the detected value of the heat exchanger outlet hot water temperature sensor 35 and the assumed detected value corresponding to the switching state of the three-way valve 29 instructed by the controller 40.

[0052] In the heating and hot water supply apparatus 1 of this embodiment, if the three-way valve 29 is normal, the expected detection value corresponding to the switching state of the three-way valve 29 (heating circulation state or hot water circulation state) instructed by the controller 40 should be reproduced as the detection value of the heat exchanger outlet hot water temperature sensor 35. Therefore, even if the three-way valve 29 does not have a limit switch or the like linked to the switching state, an abnormality in the three-way valve 29 can be detected based on the detection value of the heat exchanger outlet hot water temperature sensor 35 differing from the expected detection value. Furthermore, since the heat exchanger outlet hot water temperature sensor 35 is generally installed in the heating and hot water supply apparatus 1 to detect the temperature of hot water during hot water supply, it is possible to detect an abnormality in the three-way valve 29 by reusing the existing heat exchanger outlet hot water temperature sensor 35 without adding a new part, thereby reducing manufacturing costs.

[0053] Furthermore, in the heating and hot water supply device 1 of this embodiment, when the controller 40 instructs the three-way valve 29 to enter the heating circulation state, an abnormality in the three-way valve 29 is detected based on the fact that the expected detection value corresponding to the heating circulation state is below a predetermined threshold value, while the detection value of the heat exchanger outlet hot water temperature sensor 35 reaches the threshold value. If the three-way valve 29 instructed to enter the heating circulation state is normal, no heat medium circulates in the hot water heat exchanger 28 (internal circulation path), and the detection value of the heat exchanger outlet hot water temperature sensor 35 does not reach the threshold value. Therefore, an abnormality in the three-way valve 29 can be detected based on the fact that the detection value of the heat exchanger outlet hot water temperature sensor 35 has risen to the threshold value.

[0054] In particular, in the heating and hot water supply device 1 of this embodiment, different thresholds are set depending on the detection value (initial detection value) of the heat exchanger hot water temperature sensor 35 at the time when the controller 40 instructs the three-way valve 29 to switch to the heating circulation state, and the threshold is set higher as the initial detection value is higher. For example, if the hot water supply operation was being performed (the heat medium was circulating through the hot water heat exchanger 28) before the controller 40 instructed the three-way valve 29 to switch to the heating circulation state, the initial detection value of the heat exchanger hot water temperature sensor 35 may already be high. Even in this case, if there is an abnormality in the three-way valve 29, the detection value of the heat exchanger hot water temperature sensor 35 may rise from the initial detection value. Therefore, by raising the threshold depending on the level of the initial detection value, an abnormality in the three-way valve 29 can be detected based on the detection value of the heat exchanger hot water temperature sensor 35 reaching the threshold, while preventing erroneous detections.

[0055] In addition, in the heating and hot water supply system 1 of this embodiment, when the controller 40 instructs the three-way valve 29 to enter the hot water circulation state, an abnormality in the three-way valve 29 is detected based on the fact that, while the detection value of the supply temperature sensor 25 reaches the reference value, the expected detection value corresponding to the hot water circulation state after a predetermined standby time elapses is equal to or greater than the judgment value, but the detection value of the heat exchanger outlet hot water temperature sensor 35 is less than the judgment value after the standby time elapses. If the supply temperature sensor 25 detects the reference value, this indicates that the heat medium heated by combustion in the burner 3 is circulating due to the operation of the circulation pump 23. In this state, if the three-way valve 29 instructed to enter the hot water circulation state is normal, the heat medium circulates through the hot water heat exchanger 28 (internal circulation path), causing the detection value of the heat exchanger outlet hot water temperature sensor 35 to rise and reach the judgment value. Therefore, an abnormality in the three-way valve 29 can be detected based on the fact that the detection value of the heat exchanger outlet hot water temperature sensor 35 does not rise to the judgment value.

[0056] In addition, when switching between hot water supply operation and heating operation is repeated, heat from the previous hot water operation remains in hot water heat exchanger 28, and the detected value of heat exchanger outlet hot water temperature sensor 35 may already be high when three-way valve 29 is instructed to switch to the hot water circulation state. In this case, if an abnormality occurs in three-way valve 29 and the state is not switched to the hot water circulation state, and the heat medium does not circulate in hot water heat exchanger 28 (internal circulation path), the standby time is provided in heating and hot water supply device 1 of this embodiment, and the detected value of heat exchanger outlet hot water temperature sensor 35 will fall below the judgment value before the standby time has elapsed, making it possible to detect an abnormality in three-way valve 29.

[0057] The heating and hot water supply device 1 of the above-described embodiment also has the following variations. The following describes the variations, focusing on the differences from the above-described embodiment. In the description of the variations, the same components as those in the above-described embodiment are given the same reference numerals and will not be described again.

[0058] 6 is a flowchart of a modified heating abnormality detection process executed as part of the three-way valve abnormality detection process by controller 40. As shown in the figure, the modified heating abnormality detection process first acquires, as an initial detection value, the detection value of heat exchanger outlet hot water temperature sensor 35 at the time when the heating abnormality detection process is started based on an instruction to switch three-way valve 29 to the heating circulation state (STEP 30).

[0059] Next, it is determined whether the acquired initial detection value is less than a specified value (STEP 31). This specified value is pre-stored in the storage means 40a of the controller 40. If the initial detection value is less than the specified value (STEP 31: yes), it is determined whether the rising gradient of the detection value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than a specified rising gradient (STEP 32). The rising gradient of the detection value of the heat exchanger outlet hot water temperature sensor 35 is the amount of change (amount of increase) in the detection value per unit time, and it differs greatly between when the three-way valve 29 is normal and when it is abnormal.

[0060] 7 is a graph comparing the gradient of increase in the detected value of heat exchanger outlet hot water temperature sensor 35 when three-way valve 29 is normal and when it is abnormal, with time on the horizontal axis and the detected value of heat exchanger outlet hot water temperature sensor 35 on the vertical axis. If three-way valve 29 is operating normally and switched to the heating circulation state, the heat medium does not circulate through hot water heat exchanger 28 (internal circulation path). However, because three-way valve 29 is located at the connection between branch passage 27 and return passage 22 (see FIG. 1), and branch passage 27 is connected to supply passage 21, heat is transferred from supply passage 21 to hot water heat exchanger 28 of branch passage 27 via the heat medium, even when three-way valve 29 is in the heating circulation state. Therefore, although the assumed detection value of the heat exchanger outlet hot water temperature sensor 35 gradually rises as shown by the solid line in Figure 7, the rising gradient of the assumed detection value is gentler than the specified rising gradient shown by the dashed line, and this specified rising gradient is stored in advance in the memory means 40a of the controller 40 in correspondence with the heating circulation state of the three-way valve 29.

[0061] In contrast, if an abnormality occurs in the three-way valve 29 and the hot water circulation state is established, the heat medium circulates through the hot water heat exchanger 28 (internal circulation path), causing the detected value of the heat exchanger hot water outlet temperature sensor 35 to rise sharply as shown by the dotted line in Figure 7, with the gradient of this rise being steeper than the specified gradient of rise.

[0062] 6, if the rising gradient of the detected value of the heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the specified rising gradient (YES in STEP 32), an abnormality in the three-way valve 29 is detected (STEP 33), and the abnormality in the three-way valve 29 is notified (STEP 34). Then, the heating abnormality detection process in FIG. 6 and the three-way valve abnormality detection process in FIG. 3 are terminated.

[0063] On the other hand, if the gradient of increase in the value detected by heat exchanger outlet hot water temperature sensor 35 is less than the specified gradient (STEP 32: no), the process determines whether the monitoring period has ended (STEP 35). The monitoring period is set to the time from when three-way valve 29 is instructed to switch to the heating circulation mode until a predetermined time (e.g., one minute) has elapsed. If the monitoring period has not yet ended (STEP 35: no), the process returns to STEP 32 and repeatedly determines whether the gradient of increase in the value detected by heat exchanger outlet hot water temperature sensor 35 is equal to or greater than the specified gradient. If the gradient of increase in the value detected by heat exchanger outlet hot water temperature sensor 35 does not exceed the specified gradient and the monitoring period ends (STEP 35: yes), the three-way valve 29 is determined to be normal, and the heating abnormality detection process of FIG. 6 is terminated, and the process returns to the three-way valve abnormality detection process of FIG. 3. The monitoring period in the modified example corresponds to the "predetermined period" in the present invention.

[0064] The above describes the case where the initial detection value of the heat exchanger outlet hot water temperature sensor 35 is less than the specified value (STEP 31: yes). In contrast, if the initial detection value is equal to or greater than the specified value (STEP 31: no), the heating abnormality detection process of FIG. 6 is terminated and the process returns to the three-way valve abnormality detection process of FIG. 3. For example, if the hot water supply operation was being performed (heat medium was circulating through the hot water heat exchanger 28) before the three-way valve 29 was instructed to switch to the heating circulation mode, the initial detection value of the heat exchanger outlet hot water temperature sensor 35 may already be high. In this case, even if there is an abnormality in the three-way valve 29, the detection value of the heat exchanger outlet hot water temperature sensor 35 is unlikely to increase (the increase gradient is gradual), making it difficult to detect an abnormality in the three-way valve 29 based on the increase gradient. Therefore, if the initial detection value is equal to or greater than the specified value, an abnormality in the three-way valve 29 is not detected based on the increase gradient. If the heating abnormality detection process of the modified example (FIG. 6) is terminated because the initial detection value is equal to or greater than the specified value, the heating abnormality detection process of the above-described embodiment (FIG. 4) may be subsequently executed. Furthermore, if there is a sufficient difference between the set value of the heat medium temperature during heating operation based on the heating temperature set by heating remote control 42 and the initial detection value of heat exchanger outlet hot water temperature sensor 35, an abnormality in three-way valve 29 can be detected based on the rising slope of the detection value of heat exchanger outlet hot water temperature sensor 35. Therefore, the specified value may be changeable depending on the set value of the heat medium temperature during heating operation, and the higher the set value of the heat medium temperature during heating operation, the higher the specified value may be.

[0065] As described above, in the modified heating and hot water supply device 1, if the initial detection value of the heat exchanger outlet hot water temperature sensor 35 at the time when the controller 40 instructs the three-way valve 29 to enter the heating circulation state is less than the specified value, an abnormality in the three-way valve 29 is detected based on the fact that the rising gradient within the monitoring period of the assumed detection value corresponding to the heating circulation state is less than the specified rising gradient, while the detection value of the heat exchanger outlet hot water temperature sensor 35 has risen by more than the specified rising gradient within the monitoring period.

[0066] In this modified heating and hot water supply apparatus 1, assuming that the initial detection value of heat exchanger outlet hot water temperature sensor 35 is lower than a specified value when controller 40 instructs three-way valve 29 to enter the heating circulation state, if there is an abnormality in three-way valve 29 (if the heating medium is circulating through hot water heat exchanger 28), the detection value of heat exchanger outlet hot water temperature sensor 35 will rise more rapidly than when it is normal, and therefore an abnormality in three-way valve 29 can be detected based on whether the rising gradient of the detection value of heat exchanger outlet hot water temperature sensor 35 is equal to or greater than a specified rising gradient within the monitoring period. Detecting an abnormality in three-way valve 29 based on the rising gradient of the detection value of heat exchanger outlet hot water temperature sensor 35 in this way makes it possible to quickly detect an abnormality in three-way valve 29 before the detection value of heat exchanger outlet hot water temperature sensor 35 rises to a predetermined threshold.

[0067] The above describes the heating and hot water supply device 1 in the embodiment and modified examples, but the present invention is not limited to the above embodiment and modified examples, and can be implemented in various forms within the scope of the gist of the present invention.

[0068] For example, in the above-described embodiment, the three-way valve 29 is provided at the connection between the branch passage 27 and the return passage 22. However, the location of the three-way valve 29 is not limited thereto, and it may be at the connection between the branch passage 27 and the supply passage 21. Even in this case, the three-way valve 29 can switch between the heating circulation mode and the hot water circulation mode, and the present invention can be applied. Note that when the three-way valve 29 is provided at the connection between the branch passage 27 and the supply passage 21, the branch passage 27 communicates with the return passage 22, and therefore, when the three-way valve 29 is in the heating circulation mode, heat may be transferred from the return passage 22 to the hot water heat exchanger 28 of the branch passage 27 via a heat medium.

[0069] In the above-described embodiment, the first heat exchanger 15 and the second heat exchanger 16 are provided, and the circulating heat medium is preheated in the second heat exchanger 16 and then heated in the first heat exchanger 15. However, this is not limiting, and the second heat exchanger 16 may be omitted and the heat medium may be heated only by the first heat exchanger 15.

[0070] In the above-described embodiment, the water supply passage 30 and the hot water outlet passage 31 are connected by the bypass passage 36, and the mixing ratio of the hot water heated by the hot water heat exchanger 28 and the clean water that has passed through the bypass passage 36 can be changed by the bypass servo 37. However, this is not limited to this, and the bypass passage 36 and bypass servo 37 may be omitted by adopting a configuration in which the user appropriately adjusts the mixing ratio of the hot water outlet and the supply water using a mixing faucet. In this case, it is not necessary to separately provide the heat exchanger outlet hot water temperature sensor 35 and the outlet hot water temperature sensor 38, and they may be integrated into a single temperature sensor.

[0071] In the above-described embodiment, the hot water supply remote control 41 and the heating remote control 42 are provided, but the present invention is not limited to this, and a single remote control that combines the hot water supply remote control 41 and the heating remote control 42 may be used to perform both the hot water supply operation and the heating operation.

[0072] In the above-described embodiment, the panel radiator 20 is used as an example of the heating terminal. However, the heating terminal is not limited to the panel radiator 20, and may be a bathroom heater / dryer, a fan convector, a floor heater, or the like, as long as it has a heat dissipation portion.

[0073] In the above-described embodiment, the heating means for heating the heat transfer medium is configured to burn the mixed gas using the burner 3. However, the configuration of the heating means is not limited to this, and may be an electric heater, a heat pump, a fuel cell, or the like. [Explanation of symbols]

[0074] 1...heating and hot water heater, 2...housing, 3...burner, 4...combustion unit; 5...combustion fan; 6...junction; 7...Air supply passage, 8...Gas supply passage, 9...Zero governor, 11...spark plug, 12...flame rod, 13...check valve, 15...first heat exchanger, 16...second heat exchanger, 17...exhaust duct, 18...exhaust port, 19...air intake port, 20...panel radiator, 20a...pipe, 21...outgoing passage, 22...return passage, 22a...terminal side return passage, 22b...heat exchange side return passage, 23...circulation pump, 24... Return temperature sensor, 25... Forward temperature sensor, 27... Branch passage, 28...hot water heat exchanger, 29...three-way valve, 30...water supply passage, 31...hot water outlet passage, 32...water volume sensor, 33...water volume servo, 34...water supply temperature sensor, 35...heat exchange outlet hot water temperature sensor, 36...bypass passage, 37...Bypass servo, 38...Outlet hot water temperature sensor, 40...Controller, 40a...storage means, 41...hot water supply remote control, 42...heating remote control, 50... valve chamber, 51... hot water supply side valve body, 52... heating side valve body, 53...moving axis, 54...drive mechanism.

Claims

1. A heating and hot water supply device capable of performing a heating operation in which a heat medium is circulated to a heating terminal for heating, and a hot water supply operation in which the shared heat medium is circulated to a hot water heat exchanger and water supplied to the hot water heat exchanger is heated by heat exchange with the heat medium to produce hot water, an external circulation path for circulating the heat medium to the heating terminal; an internal circulation path that includes a common portion with the external circulation path and circulates the heat medium to the hot water heat exchanger; a circulation pump that sends the heat medium in a predetermined direction in the common portion; a heating means capable of heating the heat medium in the common portion; a first temperature sensor provided downstream of the heating means in the common portion, the first temperature sensor detecting the temperature of the heat medium heated by the heating means; a circulation switching means for switching between a heating circulation state in which the heat medium is circulated in the external circulation path and a hot water circulation state in which the heat medium is circulated in the internal circulation path; a switching control means for controlling the switching of the circulation switching means; a second temperature sensor for detecting the temperature of the hot water heated by the hot water heat exchanger; a storage means for storing in advance an assumed detected value, which is a detected value of the second temperature sensor assumed when the circulation switching means is normal, in association with a switching state of the circulation switching means; an abnormality detection means for detecting an abnormality in the circulation switching means based on a difference between the assumed detection value corresponding to the switching state of the circulation switching means instructed by the switching control means and the detection value of the second temperature sensor; A heating and hot water supply device comprising:

2. The heating and hot water supply device according to claim 1, When the heating circulation state is instructed by the switching control means, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that the assumed detection value corresponding to the heating circulation state is less than a predetermined threshold value while the detection value of the second temperature sensor reaches the threshold value. A heating and hot water supply device characterized by the above.

3. The heating and hot water supply device according to claim 2, The threshold value is set differently depending on an initial detection value, which is a detection value of the second temperature sensor at the time when the heating circulation state is instructed by the switching control means, and the higher the initial detection value, the higher the threshold value. A heating and hot water supply device characterized by the above.

4. The heating and hot water supply device according to claim 1, The storage means stores the change in the assumed detection value over time, When the detected value of the second temperature sensor at the time when the heating circulation state is instructed by the switching control means is less than a specified value, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that the rising gradient, which is the change over time of the assumed detected value corresponding to the heating circulation state within a specified period, is less than the specified rising gradient, while the detected value of the second temperature sensor rises to or exceeds the specified rising gradient within the specified period. A heating and hot water supply device characterized by the above.

5. The heating and hot water supply device according to claim 1, When the hot water supply circulation state is instructed by the switching control means, the abnormality detection means detects an abnormality in the circulation switching means based on the fact that, in a state in which the detected value of the first temperature sensor reaches a reference value, the assumed detected value corresponding to the hot water supply circulation state after the standby time has elapsed is equal to or greater than a determination value, while the detected value of the second temperature sensor after the standby time has elapsed is less than the determination value. A heating and hot water supply device characterized by the above.

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