Heating and hot water supply system

Abstract

The system supplies hot water while avoiding blockages depending on the amount of deposits in the boiler. [Solution] The heating and hot water supply device (10) includes a heat exchanger (22) that heats tap water from a water supply passage (26) equipped with a distribution valve (28) using a heat transfer medium and supplies it to a hot water outlet passage (27), a bypass passage (29) that branches off from the water supply passage by the distribution valve and connects to the hot water outlet passage, a control means (16) that supplies hot water at a set hot water supply temperature by adjusting the valve position of the distribution valve, and a notification means. The control means has a standard valve position setting means for the distribution valve corresponding to a combination of the set hot water supply temperature and the water supply temperature. In a normal mode, hot water is supplied by adjusting the valve position so that the hot water supply temperature converges to the set hot water supply temperature. If the amount of adjustment from the standard valve position set by the standard valve position setting means to the adjusted valve position exceeds the normal adjustment range, the device switches to one of the following modes depending on the amount of adjustment: a first mode that provides notification to encourage cleaning of the heat exchanger and allows hot water supply in the normal mode; a second mode that provides notification and allows hot water supply with a lowered hot water outlet temperature; or a third mode that provides notification and prohibits hot water supply.

Description

Technical Field

[0001] The present invention relates to a heating and hot water supply apparatus having a heating function and a hot water supply function, and particularly relates to a hot water supply operation when scale deposits in a heat exchanger for hot water supply.

Background Art

[0002] Conventionally, in order to supply hot water at a set hot water supply temperature, hot water supply apparatuses that heat tap water, adjust the temperature by mixing the heated hot water with unheated tap water, and then supply the hot water have been widely used. For example, Patent Document 1 describes a hot water supply apparatus that uses combustion heat to heat tap water in a heat exchanger, and mixes the heated hot water with unheated tap water to supply hot water.

[0003] Normally, tap water contains mineral components such as calcium. The higher the content of mineral components contained in tap water (the higher the hardness), and the higher the temperature of tap water after being heated, the more easily mineral components tend to precipitate. Therefore, the mineral components in tap water precipitate when heated in the heat exchanger, and deposit as scale inside the heat exchanger. Since scale narrows the passage for hot water inside the heat exchanger, the flow rate of hot water flowing through the heat exchanger decreases.

[0004] To address this issue, the hot water supply apparatus of Patent Document 1 is equipped with a scale collection means on the outlet side of the heat exchanger. In addition to the increase in water flow resistance caused by scale deposition inside the heat exchanger, the water flow resistance caused by the collected scale makes the decrease in flow rate on the heat exchanger side larger than that in the case without the collection means. Then, based on the rise in the outlet hot water temperature from the heat exchanger accompanying this flow rate decrease, or the difference between the opening degree of the flow rate adjustment valve in the bypass passage and the initial set opening degree accompanying the rise in the outlet hot water temperature, the occurrence of scale clogging is detected and notified.

[0005] In addition, Patent Document 2 describes that since scale deposition impedes heat exchange with tap water, the temperature of the heat exchanger body heated by combustion heat becomes higher than that when there is no scale deposition, and this feature is used to detect scale clogging.

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2010-261651 [Patent Document 2] Patent No. 6398325 [Overview of the project] [Problems that the invention aims to solve]

[0007] On the other hand, heating and hot water supply systems that have a heating function that heats a heat transfer medium to a predetermined temperature and supplies it to an external heating terminal, and a hot water supply function that uses the heated heat transfer medium to heat tap water in a heat exchanger for hot water supply, are widely used. Even in such heating and hot water supply systems that heat tap water with a heat transfer medium that is not as hot as combustion gas, in areas where the tap water is hard, boiler stones may accumulate in the hot water heat exchanger, reducing the heat exchange efficiency, and there is a risk that the passage of hot water in the heat exchanger may be blocked by the boiler stones. For this reason, it is required to detect boiler stone accumulation in the hot water heat exchanger, and even if boiler stone accumulation is detected, it is also required to supply hot water while avoiding blockage.

[0008] However, since the heat transfer medium for heating is not as hot as the combustion gas, it is not easy to detect boiler deposits based on changes in the boiler temperature of the heat exchanger, as described in Patent Document 2. Furthermore, in Patent Document 1, when boiler deposits are detected, the combustion heat generated is reduced, and the temperature of the hot water heated by the heat exchanger is lowered for hot water supply. However, there are cases where it is undesirable to lower the temperature of the heat transfer medium, such as during heating.

[0009] Therefore, the present invention aims to provide a heating and hot water supply system that can supply hot water while avoiding blockage depending on the degree of deposit buildup. [Means for solving the problem]

[0010] The heating and hot water supply device according to claim 1 comprises a heat exchanger that heats tap water supplied from a water supply passage by heat exchange with a heating medium and supplies hot water to a hot water outlet passage, a distribution valve disposed in the water supply passage, a bypass passage that branches off from the water supply passage at the distribution valve and is connected to the hot water outlet passage, a control means that adjusts the distribution ratio to the heat exchanger and the bypass passage by adjusting the valve position of the distribution valve and supplies hot water at a set temperature, and a notification means that notifies by display or sound, wherein the heating and hot water supply device comprises a water supply temperature detection means for detecting the water supply temperature of the tap water in the water supply passage, a hot water outlet temperature detection means for detecting the hot water outlet temperature of the hot water at the outlet of the heat exchanger, and a hot water supply temperature detection means for detecting the hot water outlet temperature downstream of the connection point between the hot water outlet passage and the bypass passage. The control means includes a standard valve position setting means for setting a standard valve position of the distribution valve corresponding to a combination of hot water set temperature and cold water temperature. When hot water is supplied in a normal mode that adjusts the valve position so that the hot water temperature converges to the hot water set temperature, if the amount of adjustment from the standard valve position set by the standard valve position setting means to the current valve position where the temperature converges to the hot water set temperature exceeds a preset normal adjustment range, the control means switches to one of the following modes depending on the amount of adjustment: a first mode in which the notification means prompts the cleaning of the heat exchanger and allows hot water supply in the same manner as the normal mode; a second mode in which the notification is given and hot water supply with a lowered hot water temperature is allowed; or a third mode in which the notification is given and hot water supply is prohibited.

[0011] According to the above configuration, when supplying hot water in normal mode, where the valve position of the distribution valve is adjusted so that the hot water temperature converges to the hot water set temperature, if the adjustment amount, which is the deviation of the valve position when the temperature converges to the hot water set temperature relative to the standard valve position corresponding to the combination of water supply temperature and hot water set temperature, exceeds the normal range, the system will switch to one of the first to third modes according to the adjustment amount. In the first to third modes, a notification is given to prompt cleaning of the heat exchanger, so it is possible to be notified of boiler stone buildup. In addition, in the first to third modes to which the system has switched according to the adjustment amount, control is performed according to the degree of boiler stone buildup estimated from the adjustment amount, so that hot water can be supplied while avoiding blockage.

[0012] The heating and hot water supply device according to claim 2 comprises a heat exchanger that heats tap water supplied from a water supply passage by heat exchange with a heating medium and supplies hot water to a hot water outlet passage, a distribution valve disposed in the water supply passage, a bypass passage that branches off from the water supply passage at the distribution valve and is connected to the hot water outlet passage, a control means that adjusts the distribution ratio to the heat exchanger and the bypass passage by adjusting the valve position of the distribution valve and supplies hot water at a set temperature, and a notification means that notifies by display or sound, wherein the heating and hot water supply device comprises a water supply temperature detection means for detecting the water supply temperature of the tap water in the water supply passage, a hot water outlet temperature detection means for detecting the hot water outlet temperature of the hot water at the outlet of the heat exchanger, and a means for detecting the hot water supply temperature of the hot water downstream of the connection point between the hot water outlet passage and the bypass passage. The system is equipped with a hot water temperature detection means, and the control means has an inspection mode for inspecting the deposit of boiler stones in the heat exchanger. In this inspection mode, when the distribution valve is set to a predetermined inspection valve position and hot water is supplied, the system is characterized by transitioning to one of the following modes: a normal mode in which the valve position is adjusted so that the hot water temperature converges to the set hot water temperature, according to the temperature difference between the predicted hot water temperature calculated based on the distribution ratio corresponding to the inspection valve position, the water supply temperature and the hot water outlet temperature, and the actual hot water temperature; a first mode in which the notification means provides notification to encourage cleaning of the heat exchanger and allows hot water supply similar to the normal mode; a second mode in which the notification is provided and hot water supply with a lowered hot water outlet temperature is allowed; or a third mode in which the notification is provided and hot water supply is prohibited.

[0013] According to the above configuration, when supplying hot water in inspection mode with the valve position of the distribution valve set to the inspection valve position, the system switches to either normal mode or one of the first to third modes depending on the temperature difference between the actual hot water temperature and the predicted hot water temperature calculated based on the distribution ratio corresponding to the inspection valve position, the water supply temperature, and the hot water outlet temperature. In the first to third modes, a notification is given to prompt cleaning of the heat exchanger, thus indicating the accumulation of boiler deposits. Furthermore, in the first to third modes, which are switched to according to the temperature difference, control is performed according to the degree of boiler deposit accumulation estimated from the temperature difference, allowing for hot water supply while avoiding blockage.

[0014] The heating and hot water supply device of claim 3 is characterized in that, in the invention of claim 2, the control means sets the position of the inspection valve based on the water supply temperature so that the predicted hot water supply temperature does not exceed a preset reference temperature. With the above configuration, when hot water is supplied at the inspection valve position, the hot water temperature can be set so as not to exceed the standard temperature that is set to prevent burns, thus enabling safe inspection of boiler deposits.

[0015] The heating and hot water supply device of claim 4 is characterized in that, in any of the inventions of claims 1 to 3, the distribution valve has within its adjustment range a distribution ratio adjustment range for adjusting the distribution ratio, a flow rate adjustment range for adjusting the flow rate while maintaining a constant distribution ratio, and a closed range for setting the flow rate to zero. According to the above configuration, when switching to the third mode and prohibiting hot water supply, the valve position of the distribution valve can be adjusted to the closed range so that hot or cold water does not come out even when the hot water tap is opened, thereby indicating that hot water cannot be supplied. [Effects of the Invention]

[0016] According to the heating and hot water supply device of the present invention, hot water can be supplied while avoiding blockage depending on the degree of deposit buildup in the boiler. [Brief explanation of the drawing]

[0017] [Figure 1] This is a diagram showing the configuration of a heating and hot water supply system according to an embodiment of the present invention. [Figure 2] Figure 1 is an exploded perspective view of the main components of the water supply distribution valve. [Figure 3] Figure 2 is an exploded perspective view of the valve body. [Figure 4] This diagram shows the adjustment range of the valve position of the water supply distribution valve. [Figure 5] This is a flowchart for estimating the deposit of lithotripsy in the example. [Figure 6] This figure shows an example of a temperature-controlled table. [Figure 7] This is a flowchart for estimating lithotripsy deposits in inspection mode. MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, modes for carrying out the present invention will be described based on working examples. Working Example

[0019] First, the configuration of the heating and hot water supply apparatus 10 will be described. The heating and hot water supply apparatus 10 has a heating function of performing heating by circulating a heat medium heated to a predetermined temperature using combustion heat between the apparatus and an external heating terminal via an external hot water heating circuit. The heating and hot water supply apparatus 10 also has a hot water supply function of heating tap water using heat of the heat medium at a predetermined temperature, and mixing the heated tap water (hot water) with unheated tap water to supply hot water adjusted to a hot water supply set temperature.

[0020] As shown in Figure 1, the heating and hot water supply apparatus 10 includes a combustion unit 12, a heating heat exchanger 13 that heats a heat medium, a heating passage 14 for connecting the heating heat exchanger 13 to an external hot water heating circuit, a heating pump 15 provided upstream of the heating heat exchanger 13 in the heating passage 14, and a control unit 16 (control means) that controls heating and hot water supply. When the combustion unit 12 performs combustion, the heating pump 15 causes the heat medium to flow so as to be supplied to the heating heat exchanger 13.

[0021] In the heating passage 14, an inlet thermistor 17 is disposed on the inlet side of the heating heat exchanger 13, and an outlet thermistor 18 is disposed on the outlet side of the heating heat exchanger 13. The inlet thermistor 17 detects the temperature of the heat medium supplied to the heating heat exchanger 13. The outlet thermistor 18 detects the temperature of the heat medium heated by the heating heat exchanger 13. Based on the temperature of the heat medium detected by these thermistors, the control unit 16 controls combustion in the combustion unit 12, the flow rate of the heat medium by the heating pump 15, and the like so that the temperature of the heated heat medium reaches a predetermined temperature (target heat medium temperature), for example 85°C.

[0022] In the combustion section 12, the supply air indicated by arrow AS and the fuel gas supplied as indicated by arrow F are mixed and supplied by the combustion fan 19. The amount of combustion heat generated by the combustion of the fuel gas in the combustion section 12 is adjusted by the rotation speed of the combustion fan 19. The heating heat exchanger 13 exchanges heat between the combustion gas generated in the combustion section 12 and the heat medium flowing through the heating passage 14, heating the heat medium to the target heat medium temperature. The combustion gas, whose temperature has decreased due to the heat exchange, is exhausted to the outside as indicated by arrow E.

[0023] A heating and hot water distribution valve 20 is located downstream of the heating heat exchanger 13 in the heating passage 14. At this heating and hot water distribution valve 20, a heating bypass passage 21 branches off from the heating passage 14, and this heating bypass passage 21 is connected upstream of the heating pump 15 in the heating passage 14. A hot water heat exchanger 22 (heat exchanger) is located in the heating bypass passage 21, which heats the tap water for hot water supply by heat exchange with a heated heat transfer medium.

[0024] The heating and hot water distribution valve 20 distributes the heat transfer medium heated by the heating heat exchanger 13 to the heating passage 14 and the heating bypass passage 21. By adjusting the distribution ratio of this heating and hot water distribution valve 20, heating operation only, hot water operation only, or simultaneous heating and hot water operation can be performed.

[0025] The heat transfer medium distributed to the heating passage 14 is supplied to the heating terminal via the hot water heating circuit, as indicated by arrow HS. The heat transfer medium returning from the heating terminal via the hot water heating circuit, as indicated by arrow HR, is supplied to the heating heat exchanger 13 via the heating pump 15. The heat transfer medium distributed to the heating bypass passage 21 has its temperature reduced by heat exchange with tap water in the hot water heat exchanger 22. The heat transfer medium that has passed through this hot water heat exchanger 22 is supplied to the heating heat exchanger 13 via the heating pump 15.

[0026] Upstream of the heating pump 15 in the heating passage 14, a supply passage 23 for supplying the heat transfer medium is connected, as indicated by arrow AF. This supply passage 23 is equipped with an on-off valve 24 for opening and closing the supply passage 23, and a pressure sensor 25 downstream of the on-off valve 24.

[0027] The hot water heat exchanger 22 is connected to a water supply passage 26 that supplies tap water from the water supply, as indicated by the arrow W, and a hot water outlet passage 27 that discharges the hot water heated by this tap water in the hot water heat exchanger 22. A water supply distribution valve 28 (distribution valve) is installed in the water supply passage 26. At the water supply distribution valve 28, a water supply bypass passage 29 (bypass passage) branches off from the water supply passage 26, and this water supply bypass passage 29 is connected to the hot water outlet passage 27.

[0028] The water supply distribution valve 28 distributes the supplied tap water to the hot water heat exchanger 22 side and the water supply bypass passage 29 side, and adjusts the distribution ratio and the flow rate of tap water passing through the water supply distribution valve 28. The hot water heated in the hot water heat exchanger 22 is mixed with unheated tap water supplied from the water supply bypass passage 29 in the hot water outlet passage 27 to adjust the temperature to reach the hot water set temperature, and is supplied from the hot water outlet passage 27 as indicated by the arrow HW.

[0029] As shown in Figures 2 and 3, the water supply distribution valve 28 is configured such that a cylindrical valve body 40, which has a pivot shaft rotated by, for example, a stepping motor, is rotatably housed in a main body 41. The main body 41 has an outlet 41a to the hot water heat exchanger 22, an outlet 41b to the water supply bypass passage 29, and a water inlet 41c.

[0030] The side wall of the cylindrical valve body 40 has an opening 40a corresponding to the hot water heat exchanger 22 side and an opening 40b corresponding to the water supply bypass passage 29 side. The cylindrical valve body 40 also has an opening 40c in the bottom wall portion 40d of the valve body 40 corresponding to the water inlet 41c. The openings 40a and 40b are formed such that their lengths in the direction parallel to the central axis C vary depending on their circumferential position on the side wall. The opening 40c is formed in a shape that approximates a semicircle, with its center coinciding with the central axis C.

[0031] The side walls and bottom walls 40d of the cylindrical valve body 40 housed in the main body 41 slide against the inner wall of the main body 41, and the tap water flowing in from the inlet 41c is introduced into the valve body 40 through the opening 40c. The tap water introduced into the valve body 40 is distributed to the hot water heat exchanger 22 side and the water supply bypass passage 29 side through the corresponding outlets 41a and 41b via two openings 40a and 40b.

[0032] The cylindrical valve body 40 is rotated around its central axis C. This changes the opening areas of the openings 40a and 40b corresponding to the two outlets 41a and 41b of the main body 41, thereby adjusting the distribution ratio. By rotating the valve body 40, for example, the opening area of ​​the opening 40c corresponding to the water inlet 41c is changed while maintaining the distribution ratio, thereby adjusting the flow rate of water flowing through the water supply distribution valve 28. For example, as shown in Figure 4, the water supply distribution valve 28 is adjusted within a rotation angle range of 0 to 310 degrees, and this adjustment range includes a range for adjusting the distribution ratio (range R3 of 80 to 215 degrees), a range for adjusting the flow rate (total flow rate) flowing through the water supply distribution valve 28 while maintaining a constant distribution ratio (range R1 of 0 to 60 degrees, range R4 of 215 to 300 degrees), and a range for closing the water supply passage 26 by setting the flow rate to zero (range R5 of 300 to 310 degrees).

[0033] As shown in Figure 1, a water flow sensor 30 and a water thermistor 31 (water temperature detection means) are installed upstream of the water distribution valve 28 in the water supply passage 26. The water flow sensor 30 detects the flow rate of tap water supplied to the water distribution valve 28, that is, the flow rate of hot water supplied to the hot water passage 4. The water thermistor 31 detects the temperature of the tap water supplied to the water distribution valve 28 (water temperature).

[0034] In the hot water outlet passage 27, a hot water outlet thermistor 32 (hot water temperature detection means) is installed on the hot water heat exchanger 22 side of the connection point with the water supply bypass passage 29, and a hot water supply thermistor 33 (hot water temperature detection means) is installed downstream of that connection point. The hot water outlet thermistor 32 detects the outlet temperature of the hot water heated by the hot water heat exchanger 22. The hot water supply thermistor 33 detects the supply temperature of the hot water supplied to the hot water outlet passage 4. The control unit 16 controls the distribution ratio of the water supply distribution valve 28, etc., so that the supply temperature detected by the hot water supply thermistor 33 ultimately converges to a preset hot water temperature.

[0035] Next, the control unit 16 will be described. The control unit 16 communicates with various sensors, such as the inlet thermistor 17, and receives detection signals from them. Based on the received detection signals, it controls the combustion fan 19, heating pump 15, heating and hot water distribution valve 20, water supply distribution valve 28, etc., thereby controlling the heating operation, hot water supply operation, and simultaneous heating and hot water supply operation.

[0036] An operation terminal 34 is connected to the control unit 16. The operation terminal 34 includes a display unit 35 capable of displaying information such as various temperatures and operating statuses, an audio output unit (not shown) that sounds a buzzer, and a switch unit 36 ​​for performing setting operations, etc. The display unit 35 and the audio output unit correspond to the notification means of the heating and hot water supply system 10. By operating the operation terminal 34, the hot water supply set temperature, the target heat medium temperature, etc., can be set.

[0037] During hot water supply operation, the control unit 16 estimates the degree of deposit buildup in the hot water heat exchanger 22 based on the valve position, which is represented by the rotation angle of the valve body 40 of the water supply distribution valve 28, and is configured to perform appropriate operations according to the degree of deposit buildup. The valve position can also be represented by the number of steps of the stepping motor corresponding to the rotation angle. This deposit buildup estimation will be explained with reference to Figure 5. In the figure, Si(i=1,2,···) represents the control step.

[0038] When the estimation of boiler deposits begins, in S1 the water supply temperature and the hot water set temperature are obtained and the process proceeds to S2. Next, in S2, based on the temperature control table, the valve position (standard valve position) of the valve body 40 of the water supply distribution valve 28 corresponding to the water supply temperature and the hot water set temperature is obtained and the process proceeds to S3. The temperature control table (standard valve position setting means) is, for example, as shown in Figure 6, a standard valve position in which the valve position that can be adjusted to the hot water set temperature for each water supply temperature has been set in advance by experiments, etc., and is stored in the control unit 16. Alternatively, instead of having a temperature control table, the control unit 16 can be configured to calculate the standard valve position corresponding to the distribution ratio that can be adjusted to the hot water set temperature based on the water supply temperature and the hot water set temperature.

[0039] In S3 of Figure 5, the valve position of the water supply distribution valve 28 (convergence valve position) when the hot water temperature converges to the hot water set temperature is obtained, and the process proceeds to S4. Then, in S4, the deviation of the convergence valve position obtained in S3 from the standard valve position, i.e., the adjustment amount from the standard valve position to the convergence valve position, is calculated, and the process proceeds to S5. Because the flow rate on the hot water heat exchanger 22 side decreases due to increased water flow resistance caused by boiler deposits, the water supply distribution valve 28 is adjusted to reduce the flow rate on the water supply bypass passage 29 side so that the hot water temperature reaches the set temperature. Therefore, this adjustment amount reflects the flow rate of hot and cold water on the hot water heat exchanger 22 side, i.e., the degree of boiler deposit accumulation in the hot water heat exchanger 22, and the degree of boiler deposit accumulation can be estimated from the adjustment amount from the standard valve position to the convergence valve position.

[0040] In S5, it is determined whether the adjustment amount calculated in S4 is within the preset normal adjustment range. Since the adjustment is made to increase the rotation angle relative to the standard valve position in order to reduce the flow rate on the water supply bypass passage 29 side, the normal adjustment range is set to an adjustment amount that corresponds to, for example, a range of +2 degrees or less in rotation angle relative to the standard valve position. If the determination in S5 is Yes, the process proceeds to S6, where it switches to normal mode and the sediment accumulation estimation is completed. If the system was in normal mode before the start of the sediment accumulation estimation, the normal mode is maintained.

[0041] If the result of S5 is No, the process proceeds to S7, where it is determined whether the adjustment amount calculated in S4 is within the preset first tolerance range. The first tolerance range is set to allow for adjustment amounts larger than the normal adjustment range, for example, by an adjustment amount equivalent to +2 degrees of rotation angle compared to the normal adjustment range. If the result of S7 is Yes, the process proceeds to S8, where it switches to the first mode and terminates the boiler deposit estimation. The first mode is a mode in which hot water is supplied at the set temperature in the same way as the normal mode, and a notification is made via a notification means recommending boiler deposit cleaning of the hot water heat exchanger 22.

[0042] On the other hand, if the result of S7 is No, the process proceeds to S9, where it is determined whether the adjustment amount calculated in S4 falls within the pre-set second adjustment tolerance range. The second adjustment tolerance range is set to allow for a larger adjustment amount than the first adjustment tolerance range, for example, by an adjustment amount equivalent to +1 degree of rotation angle compared to the first adjustment tolerance range. If the result of S9 is Yes, the process proceeds to S10, where it switches to the second mode and terminates the lithotripsy deposition estimation.

[0043] The second mode is a mode in which, for example, the flow rate of the heat medium supplied to the hot water heat exchanger 22 is reduced to lower the temperature of the hot water coming out of the hot water heat exchanger 22, and a notification is made by a notification means recommending the cleaning of the boiler of the hot water heat exchanger 22. When reducing the flow rate of the heat medium, the drive of the heating pump 15 is adjusted to reduce the flow rate of the heat medium, or the distribution ratio of the heating hot water distribution valve 20 is adjusted so that the flow rate on the heating bypass passage 21 side is reduced. If heating operation is not being performed, the temperature of the heat medium may be lowered by reducing the amount of combustion heat generated in the combustion section 12 while maintaining the flow rate of the heat medium.

[0044] If the determination in S9 is No, the process proceeds to S11, where it switches to the third mode and terminates the boiler deposit estimation. The third mode is a mode in which hot water supply is prohibited and a notification is made via a notification means recommending boiler deposit cleaning of the hot water heat exchanger 22. Prohibition of hot water supply is performed by adjusting the valve position of the water supply distribution valve 28 to a range that closes the water supply passage 26, thereby stopping the supply of tap water. At this time, the notification of prohibition of hot water supply may be made together with the notification recommending boiler deposit cleaning. When hot water supply is prohibited, no hot or cold water will come out even if the hot water tap is opened at the destination, so even if, for example, the operation terminal 34 and the hot water tap are not located close together, the situation of being unable to supply hot water can be communicated.

[0045] The boiler deposit estimation can also be configured to be performed by switching to an inspection mode to check for boiler deposits. When boiler deposit estimation is started in inspection mode, the water supply temperature is obtained in S21 in Figure 7 and the process proceeds to S22. Next, in S22, based on the temperature control table (see Figure 6), a combination of water supply temperature and valve position of the water supply distribution valve 28 is selected so that the hot water temperature is below a reference temperature set as a safe temperature that does not pose a risk of burns, and the process proceeds to S23. The reference temperature is, for example, 45°C, and regardless of the current hot water setting temperature, a valve position is selected that results in a hot water temperature (predicted hot water temperature) of, for example, 40°C when combined with the water supply temperature.

[0046] In S23, the selected valve position is set as the inspection valve position, and the valve position of the water supply distribution valve 28 is adjusted to the inspection valve position before proceeding to S24. In S24, the deviation (temperature difference) between the predicted hot water temperature and the actual hot water temperature is obtained, and the process proceeds to S25. This temperature difference reflects the flow rate of the hot water heated in the hot water heat exchanger 22. Since this flow rate of hot water reflects the degree of deposits of boiler stones that increase the water flow resistance of the hot water heat exchanger 22, the degree of deposits can be estimated from the temperature difference between the predicted hot water temperature and the actual hot water temperature in inspection mode.

[0047] In S25, it is determined whether the temperature difference obtained in S24 falls within a preset normal temperature range. Since the flow rate on the hot water heat exchanger 22 side decreases and the hot water temperature drops due to the accumulation of boiler deposits, the normal temperature range is set to, for example, within -1°C of the predicted hot water temperature. If the determination in S25 is Yes, the process proceeds to S26, where it switches to normal mode and the boiler deposit inspection is completed. If the determination in S25 is No, the process proceeds to S27, where it is determined whether the deviation falls within a first temperature tolerance range that is larger than the normal temperature range. The first temperature tolerance range is set to, for example, a range that is -0.5°C larger than the normal temperature range (for example, within -1.5°C of the predicted hot water temperature). If the determination in S27 is Yes, the process proceeds to S28, where it switches to the first mode and the boiler deposit inspection is completed.

[0048] If the result in S27 is No, proceed to S29, where it is determined whether the deviation is within the second temperature tolerance range, which is larger than the first temperature tolerance range. The second temperature tolerance range is set to a range that is, for example, -0.5°C larger than the first temperature tolerance range (for example, within -2°C of the predicted hot water temperature). If the result in S29 is Yes, proceed to S30, where the system switches to the second mode and the inspection of boiler deposits is completed. If the result in S29 is No, proceed to S31, where the system switches to the third mode and the boiler deposit estimation is completed.

[0049] During hot water supply in this inspection mode, the hot water temperature from the hot water heat exchanger 22 decreases due to boiler deposits, and even if the hot water temperature deviates from the predicted hot water temperature, it will not exceed the reference temperature, allowing for safe boiler deposit estimation in inspection mode. This transition to inspection mode may be performed, for example, by operating the control terminal 34, or it may be set to automatically switch to inspection mode on a set day of the week. When the user starts using hot water as usual without being aware of inspection mode, it can switch to normal mode or one of the first to third modes. Returning from the first to third modes to normal mode can be done by the boiler deposit estimation described above, but it may also be possible to switch to normal mode from the control terminal 34 when boiler cleaning is performed.

[0050] The operation and effects of the above-mentioned heating and hot water supply system 10 will be explained. In normal mode, the heating and hot water supply system 10 mixes tap water heated by heat exchange with a heat transfer medium in the hot water heat exchanger 22 with unheated tap water from the water supply bypass passage 29 to supply hot water, adjusting the distribution ratio of the water supply distribution valve 28 so that the hot water temperature converges to the hot water set temperature. If the valve position of the water supply distribution valve 28 when the hot water temperature converges to the hot water set temperature (convergence valve position) deviates from the standard valve position in the preset temperature control table corresponding to the tap water temperature and the hot water set temperature, the amount of adjustment from the standard valve position to the convergence valve position reflects the degree of deposits of boiler stones that increase the water flow resistance of the hot water heat exchanger 22, so the degree of deposits of boiler stones can be estimated from the amount of adjustment of the valve position. Then, if the adjustment amount is within the normal adjustment range, it switches to normal mode; if it is greater than the normal adjustment range but within the first adjustment tolerance range, it switches to the first mode; if it is greater than the first adjustment tolerance range but within the second adjustment tolerance range, it switches to the second mode; and if it is greater than the second adjustment tolerance range, it switches to the third mode.

[0051] Furthermore, if the heating and hot water supply system 10 has an inspection mode for estimating the accumulation of boiler stones in the hot water heat exchanger 22, the predicted hot water temperature is calculated based on the inspection valve position of the water supply distribution valve 28, the water supply temperature, and the temperature control table set in the inspection mode. If the actual hot water temperature deviates from the calculated predicted hot water temperature, the degree of boiler stone accumulation can be estimated from the temperature difference. If this temperature difference is within the normal temperature range, the system switches to the normal mode; if it is greater than the normal temperature range but within the first temperature tolerance range, it switches to the first mode; if it is greater than the first temperature tolerance range but within the second temperature tolerance range, it switches to the second mode; and if it is greater than the second temperature tolerance range, it switches to the third mode.

[0052] In modes 1 through 3, the system provides a notification prompting cleaning of the hot water heat exchanger 22 before it becomes clogged with boiler deposits, thereby encouraging the removal of accumulated boiler deposits. In mode 1, hot water is supplied in the same way as in normal mode, but in mode 2, the water temperature from the hot water heat exchanger 22 is reduced to slow down the deposition of boiler deposits in the hot water heat exchanger 22, making it less likely to clog. In mode 3, hot water supply is prohibited before the hot water heat exchanger 22 becomes clogged and malfunctions, preventing the need to replace the hot water heat exchanger 22. In this way, the heating and hot water supply system 10 can operate according to the degree of boiler deposit accumulation based on the boiler deposit estimation results, and can supply hot water while avoiding blockage.

[0053] The inspection location is set based on the temperature control table and water supply temperature to ensure that the predicted hot water temperature does not exceed a standard temperature set as a safe temperature that eliminates the risk of burns. Therefore, boiler deposit inspection can be performed safely.

[0054] The adjustment range of the water supply distribution valve 28 includes a distribution ratio adjustment range for adjusting the distribution ratio, a flow rate adjustment range for adjusting the flow rate, and a closing range for closing the valve by setting the flow rate to zero. Therefore, when switching to the third mode, it is possible to prevent hot or cold water from coming out even if the hot water tap is opened. Furthermore, even if, for example, the hot water tap and the operating terminal 34 are located in different places, it is possible to notify the user that hot water is unavailable.

[0055] Furthermore, those skilled in the art can implement the present invention in various forms with modifications to the above embodiments without departing from the spirit of the invention, and the present invention encompasses such modifications. [Explanation of Symbols]

[0056] 10: Heating and hot water supply system 12: Combustion section 13:Heat exchanger 14: Heated passageway 15: Heating pump 16: Control Unit (Control Means) 17: Inlet thermistor 18: Exit thermistor 19: Combustion fan 20: Heating and hot water distribution valve 21: Heating bypass passage 22: Hot water heat exchanger 23: Supply passage 24: Shut-off valve 25: Pressure sensor 26:Water supply passage 27: Hot spring access passage 28: Water supply distribution valve (distribution valve) 29: Water supply bypass passage (bypass passage) 30: Water supply flow sensor 31: Water supply thermistor (means for detecting water supply temperature) 32: Hot water outlet thermistor (means for detecting hot water outlet temperature) 33: Hot water thermistor (means for detecting hot water temperature) 34: Operating terminal 35: Display section 36: Switch section 40: Valve body 40a, 40b, 40c: opening 41: Main body 41a, 41b: Outlet 41c: Inlet

Claims

1. A heating and hot water supply system comprising: a heat exchanger that heats tap water supplied from a water supply passage through heat exchange with a heating medium and supplies hot water to a hot water outlet passage; a distribution valve disposed in the water supply passage; a bypass passage that branches off from the water supply passage at the distribution valve and is connected to the hot water outlet passage; a control means that adjusts the distribution ratio to the heat exchanger and the bypass passage by adjusting the valve position of the distribution valve to supply hot water at a set temperature; and a notification means that notifies by display or sound, The system includes a water supply temperature detection means for detecting the water supply temperature of the tap water in the water supply passage, a hot water outlet temperature detection means for detecting the hot water outlet temperature of the hot water at the outlet of the heat exchanger, and a hot water supply temperature detection means for detecting the hot water supply temperature downstream of the connection point between the hot water outlet passage and the bypass passage. The control means includes a standard valve position setting means for setting a standard valve position of the distribution valve corresponding to a combination of hot water set temperature and water supply temperature, and when hot water is supplied in a normal mode in which the valve position is adjusted so that the hot water temperature converges to the hot water set temperature, if the amount of adjustment from the standard valve position set by the standard valve position setting means to the current valve position where the temperature converges to the hot water set temperature exceeds a preset normal adjustment range, the heating and hot water supply device is characterized in that, depending on the amount of adjustment, the notification means provides notification to encourage cleaning of the heat exchanger and allows hot water supply in the same manner as the normal mode, the device switches to one of the following modes: a first mode in which the notification is given and hot water supply with a lowered hot water temperature is allowed, or a third mode in which the notification is given and hot water supply is prohibited.

2. A heating and hot water supply system comprising: a heat exchanger that heats tap water supplied from a water supply passage through heat exchange with a heating medium and supplies hot water to a hot water outlet passage; a distribution valve disposed in the water supply passage; a bypass passage that branches off from the water supply passage at the distribution valve and is connected to the hot water outlet passage; a control means that adjusts the distribution ratio to the heat exchanger and the bypass passage by adjusting the valve position of the distribution valve to supply hot water at a set temperature; and a notification means that notifies by display or sound, The system includes a water supply temperature detection means for detecting the water supply temperature of the tap water in the water supply passage, a hot water outlet temperature detection means for detecting the hot water outlet temperature of the hot water at the outlet of the heat exchanger, and a hot water supply temperature detection means for detecting the hot water supply temperature downstream of the connection point between the hot water outlet passage and the bypass passage. The heating and hot water supply system is characterized in that the control means has an inspection mode for inspecting the deposit of boiler stones in the heat exchanger, and when the distribution valve is set to a predetermined inspection valve position and hot water is supplied in this inspection mode, it switches to one of the following modes: a normal mode in which the valve position is adjusted so that the hot water temperature converges to the hot water set temperature according to the temperature difference between the predicted hot water temperature calculated based on the distribution ratio corresponding to the inspection valve position, the water supply temperature and the hot water outlet temperature and the actual hot water temperature; a first mode in which the notification means provides notification to encourage cleaning of the heat exchanger and allows hot water supply in the same manner as the normal mode; a second mode in which the notification is provided and hot water supply with a lowered hot water outlet temperature is allowed; or a third mode in which the notification is provided and hot water supply is prohibited.

3. The heating and hot water supply device according to claim 2, characterized in that the control means sets the position of the inspection valve based on the water supply temperature so that the predicted hot water supply temperature does not exceed a preset reference temperature.

4. The heating and hot water supply device according to any one of claims 1 to 3, characterized in that the distribution valve has, within the adjustment range of its valve position, a distribution ratio adjustment range for adjusting the distribution ratio, a flow rate adjustment range for adjusting the flow rate while maintaining a constant distribution ratio, and a closing range for setting the flow rate to zero.

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