Linked hot water system

Abstract

To provide a connection-type hot water supply system capable of determining blockage of a water inlet filter.SOLUTION: In a connection-type hot water supply system (10) including a plurality of combustion-type hot water supply devices (11-14) arranged in parallel between water supply piping (1) and hot water supply piping (2); and control means (15) for changing the number of hot water supply devices to be operated to adjust a heating capacity according to a use amount of supplied hot water, the hot water supply devices (11-14) each include: passing water amount detection means for detecting a passing water amount of clean water introduced from the water supply piping (1); and a water inlet filter (33) mounted on a clean water introduction portion (29a) from the water supply piping (1). The control means (15) determines blockage of the water inlet filters (33) disposed on each of the hot water supply devices (11-14) by comparing the passing water amounts of the hot water supply devices in operation, when the hot water supply devices (11-14) are simultaneously being operated.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a linked hot water supply system that includes multiple hot water supply devices and a system control device that controls the number of operating hot water supply devices, and that changes the number of operating devices to supply hot water in order to adjust the heating capacity according to the amount of hot water used. [Background technology]

[0002] Conventionally, combustion-type hot water heaters have been used for general households, adjusting their heating capacity to supply hot water at a set target temperature. The heating capacity of the hot water heater is changed and adjusted according to the temperature of the clean water introduced into the hot water heater, the target temperature, and the hot water outlet flow rate (flow rate). For example, if the target temperature is too high and the heating capacity is insufficient, the hot water outlet flow rate is reduced, giving priority to supplying hot water at the set target temperature.

[0003] On the other hand, in dormitories, accommodation facilities, sports gyms, etc., where hot water demand is concentrated and a large amount of hot water is required due to multiple users taking showers, etc., linked hot water supply systems consisting of multiple combustion-type hot water supply devices are used. Linked hot water supply systems supply hot water at a set target temperature to the hot water supply pipe, and hot water users use hot water at the desired temperature from a hot water tap with a temperature adjustment function.

[0004] The linked hot water supply system adjusts the heating capacity of the operating hot water supply devices according to the amount of hot water used (the amount of hot water flowing at the target temperature) and changes the number of operating hot water supply devices, so it can handle not only large amounts of hot water but also small amounts of hot water with only one operating device. The number of operating hot water supply devices is changed by one when, for example, certain additional operation conditions or operation stop conditions are met.

[0005] Each of the hot water heaters in a linked hot water supply system is equipped with a water inlet filter at the water inlet that captures foreign matter that flows in with the clean water. If this water inlet filter becomes partially clogged with the captured foreign matter, the amount of water flowing through the hot water heater decreases, making it impossible to supply hot water at the target temperature at a sufficient flow rate. Regarding how to deal with such blockages, Patent Document 1, for example, describes a sludge solubilization device that has two supply paths, each equipped with a filter and a pump, and is configured to determine a blockage when the flow rate of one of the supply paths when the pump is operating decreases and switch to the other supply path. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4448263 Summary of the Invention [Problem to be solved by the invention]

[0007] The combustion-type water heater starts operating when the flow rate of the clean water to be heated exceeds a predetermined start flow rate, and supplies hot water by adjusting the heating capacity according to the temperature of the incoming clean water, the target temperature, and the hot water outlet flow rate. In a linked hot water supply system equipped with multiple combustion-type water heaters, it is possible to switch the flow path by switching the water heater to be operated.

[0008] However, because the hot water outlet flow rate (flow rate) of an operating water heater fluctuates depending on the amount of hot water used, it is difficult to determine whether the water inlet filter is clogged based on a decrease in flow rate, as in Patent Document 1. Furthermore, a water heater with a somewhat clogged water inlet filter has difficulty increasing the flow rate of the clean water to be heated, which may result in problems such as a delay in starting operation or an inability to satisfy additional operation conditions. Furthermore, if the water heater with the most clogged water inlet filter is the first to operate, it may not be able to reach the predetermined start flow rate, preventing other water heaters from operating, and potentially resulting in an inability to supply hot water.

[0009] SUMMARY OF THE INVENTION An object of the present invention is to provide a linked hot water system that is capable of determining whether an inlet filter is clogged. [Means for solving the problem]

[0010] The linked hot water supply system of the invention of claim 1 is a linked hot water supply system comprising a plurality of combustion-type hot water supply devices installed in parallel between a water supply pipe and a hot water supply pipe, and a control means for changing the number of hot water supply devices to be operated in order to adjust the heating capacity according to the amount of hot water used, wherein each of the plurality of hot water supply devices has a water flow detection means for detecting the amount of clean water flowing from the water supply pipe, and a water inlet filter equipped at the inlet portion of the clean water from the water supply pipe, and the control means is characterized in that when a plurality of the hot water supply devices are operating simultaneously, it determines whether the water inlet filter equipped on each of the plurality of the hot water supply devices is clogged by comparing the water flow rates of the water supply devices that are operating.

[0011] According to the above configuration, the control means can compare the water flow rates of multiple water heaters operating simultaneously, and determine that the water inlet filter installed in the drinking water inlet section of a water heater with a small water flow rate is clogged.

[0012] The linked hot water supply system of the invention of claim 2 is characterized in that, in the invention of claim 1, the multiple hot water supply devices each have a water flow adjustment means for adjusting the amount of water flowing when in operation, and the control means compares the water flow rates of the multiple hot water supply devices in operation when the opening degree of the water flow adjustment means of the hot water supply device that was last operated among the multiple hot water supply devices in operation is maximum. According to the above configuration, each of the multiple hot water supply devices in the linked hot water supply system is equipped with a water volume adjustment device. When the water volume adjustment device of the hot water supply device that last started operating among the multiple hot water supply devices operating simultaneously has the maximum opening degree, this means that the water volume adjustment devices of all the operating hot water supply devices are also at the maximum opening degree, and the water flow rates of the multiple operating hot water supply devices should be equal. By utilizing this, it is possible to determine whether the water inlet filter is clogged by comparing the water flow rates of the multiple hot water supply devices operating simultaneously.

[0013] The linked hot water supply system of the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the control means excludes from the candidates for operation any hot water supply device among the multiple hot water supply devices whose water inlet filter is determined to be clogged. According to the above configuration, the water heater whose water inlet filter is determined to be clogged is not operated, thereby preventing malfunctions caused by the clogged water inlet filter. Also, maintenance of the water heater whose water inlet filter is determined to be clogged can be performed without interfering with the supply of hot water by other water heaters. [Effects of the Invention]

[0014] According to the linked hot water supply system of the present invention, it is possible to determine whether the water inlet filter is clogged, thereby encouraging maintenance of the hot water supply device in which it has been determined that the water inlet filter is clogged, and preventing malfunctions caused by the clogged water inlet filter from occurring. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing a linked hot water supply system according to an embodiment of the present invention; [Figure 2] 1 is an explanatory diagram of a hot water supply device constituting a linked hot water supply system according to an embodiment. [Figure 3] 10 is a flowchart of the control of the number of operating units according to the embodiment. [Figure 4] FIG. 10 is an explanatory diagram of the transition of heating capacity according to the example. [Figure 5] 10 is a flowchart of a process for determining whether an inlet filter is clogged according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the mode for carrying out the present invention will be described based on examples. [Example]

[0017] As shown in FIG. 1, tap water is supplied to water supply pipe 1 as indicated by arrow W. A linked hot water supply system 10 is installed so that the tap water introduced from water supply pipe 1 is heated to a target temperature and supplied to hot water supply pipe 2, which is equipped with multiple hot water taps F1-Fm. This linked hot water supply system 10 includes multiple (four in this example) hot water heaters 11-14 and a system controller 15 as control means communicatively connected to these hot water heaters 11-14 to control the number of operating units. System controller 15 includes an operation remote control 15a for setting, for example, the outlet hot water temperature of the linked hot water supply system 10. The multiple hot water heaters 11-14 are connected in parallel between water supply pipe 1 and hot water supply pipe 2, and any of the hot water heaters 11-14 can supply hot water to the multiple hot water taps F1-Fm. The multiple hot water taps F1-Fm have the function of adjusting the temperature, for example, by mixing the hot water with tap water, so that hot water users can adjust the temperature to their desired level. The number of water heating devices constituting linked hot water system 10 is not limited to four, but may be two or more.

[0018] Next, hot water supply devices 11-14 will be described, but since these hot water supply devices 11-14 have the same configuration, the description will be given of hot water supply device 11 and the description of hot water supply devices 12-14 will be omitted. As shown in Fig. 2, water heater 11 is a combustion-type water heater configured to use the heat of combustion of fuel gas in combustion section 21 to heat hot water flowing through heat exchange section 22. This water heater 11 has water supply section 23 that supplies clean water to heat exchange section 22, and hot water outlet section 24 that adjusts the temperature of the hot water heated in heat exchange section 22 and outputs the hot water.

[0019] Combustion section 21 has burner 25 having multiple combustion compartments, fuel regulating valve 26 that adjusts the flow rate of fuel gas supplied to burner 25, combustion fan 27 that supplies combustion air, and ignition device 28 that ignites burner 25 using electric discharge. Burner 25 is equipped with on-off valves 25a to 25d corresponding to the multiple combustion compartments.

[0020] The water supply section 23 has a water supply passage 29 connecting the water supply pipe 1 and the heat exchange section 22, a water supply valve 30 that opens and closes the water supply passage 29, a water supply temperature sensor 31 that detects the temperature of the clean water (the supply water temperature), and a water supply flow rate sensor 32 that detects the flow rate of the clean water (the supply water flow rate) supplied to the heat exchange section 22. The water supply passage 29 is detachably equipped with an inlet water filter 33 at an inlet section 29a of the clean water from the water supply pipe 1 for capturing foreign matter that flows in with the clean water.

[0021] The hot water outlet section 24 has a hot water outlet passage 34 connecting the heat exchange section 22 and the hot water supply pipe 2, a bypass passage 35 branching off from the water supply passage 29 downstream of the water supply valve 30 and connected to the hot water outlet passage 34, and a bypass flow rate adjustment valve 36. The bypass flow rate adjustment valve 36 adjusts the flow rate of clean water flowing from the water supply passage 29 into the bypass passage 35. The hot water outlet passage 34 is equipped with a first hot water outlet temperature sensor 37 that detects the temperature of the hot water heated in the heat exchange section 22, a second hot water outlet temperature sensor 38 that detects the temperature of the hot water (outlet hot water temperature) adjusted by mixing the heated hot water with clean water from the bypass passage 35, and a hot water outlet flow rate adjustment valve 39. The hot water outlet flow rate adjustment valve 39 adjusts the flow rate of clean water introduced from the water supply pipe 1 by adjusting the hot water outlet flow rate of the hot water supplied to the hot water supply pipe 2, i.e., is a water rate adjustment means that adjusts the water flow rate of the hot water heater 11.

[0022] Water heater 11 has a control unit 40 that controls the hot water supply operation of water heater 11 in cooperation with system control device 15. Control unit 40 acquires the flow rate detected by water supply flow rate sensor 32 and the temperatures detected by water supply temperature sensor 31 and first and second hot water outlet temperature sensors 37, 38. Based on these detected flow rates and temperatures, control unit 40 changes and adjusts the heating capacity by controlling the rotation speed of combustion fan 27, the opening degree of fuel adjustment valve 26, and the opening and closing of on-off valves 25a to 25d, and also adjusts the opening degree of bypass flow rate adjustment valve 36. This performs a hot water supply operation in which hot water at a set target temperature is supplied to hot water supply pipe 2.

[0023] For example, if hot water at the target temperature cannot be supplied because the amount of hot water used is large, control unit 40 adjusts the opening of hot water outlet flow rate adjustment valve 39 to reduce the water flow rate, thereby enabling hot water at the target temperature to be supplied. The water flow rate of hot water heater 11 is calculated by control unit 40 based on the flow rate detected by water supply flow rate sensor 32, the opening of bypass flow rate adjustment valve 36, and the opening of hot water outlet flow rate adjustment valve 39. Therefore, water supply flow rate sensor 32, bypass flow rate adjustment valve 36, hot water outlet flow rate adjustment valve 39, and control unit 40 constitute a water flow rate detection means that detects the water flow rate of hot water heater 11.

[0024] System control device 15 sets one of multiple water heating devices 11-14 (for example, water heating device 11) that are candidates for operation in hot water supply operation as a main water heating device, and sets the water heating devices other than the main water heating device (for example, water heating devices 12-14) as sub-water heating devices. The main water heating device is the water heating device that is operated first when hot water supply starts. The sub-water heating devices are water heating devices that are not operated when hot water supply starts, but are operated additionally while hot water is being supplied. Since there is one main water heating device, the number N of sub-water heating devices is N=3.

[0025] When setting up the sub-water heating devices, the operation priority (order of additional operation) of the sub-water heating devices other than the main water heating device with the highest operation priority is set, for example, the first sub-water heating device, the second sub-water heating device, and the third sub-water heating device. Furthermore, in order to reduce the difference in accumulated operation time or operation load among multiple water heating devices 11-14, system control device 15 performs a rotation setting to switch the main water heating device and the sub-water heating devices, for example, periodically or according to the accumulated operation time.

[0026] Control unit 40 of the main hot water supply device opens water supply valve 30 and opens hot water outlet flow rate adjustment valve 39, for example, fully. Control unit 40 of the sub-hot water supply device closes water supply valve 30 and opens hot water outlet flow rate adjustment valve 39 to a predetermined degree (for example, half open). When any of hot water taps F1 to Fm is opened and the water supply flow rate of the main hot water supply device exceeds a predetermined operation start flow rate, hot water supply operation begins using only the main hot water supply device.

[0027] When the heating capacity of the main water heater exceeds a specified value, for example, and an additional operation condition is met, and there are inactive sub-water heaters among the operation candidates, system control device 15 additionally operates one of the inactive sub-water heaters with the highest operation priority. Because the incoming tap water is distributed among multiple operating water heaters, system control device 15 adjusts the aperture of outlet hot water flow rate adjustment valve 39 of the water heater that was last to start operating, for example, so that the heating capacity of the water heater that started operating first is maintained. Note that the aperture of outlet hot water flow rate adjustment valve 39 of the last water heater may also be adjusted so that the heating capacities of multiple operating water heaters are equal.

[0028] For the additionally operated sub-water heater, if the opening of hot water outlet flow rate adjustment valve 39 is maximized and the heating capacity exceeds a specified value, the additional operation conditions are met, and there is an inactive sub-water heater among the operation candidates, then one more inactive sub-water heater is operated. In this way, when the additional operation conditions are met for the last-operated hot water heater among the operating water heaters and there is an operable sub-water heater, system control device 15 controls the number of units to be operated, operating each additional unit at a time, and increasing the heating capacity according to the amount of hot water used so that heating capacity does not become insufficient.

[0029] For example, when the hot water tap F1 is opened and the water supply flow rate sensor 32 of the main hot water supply device detects a flow rate equal to or greater than a predetermined start flow rate, the main hot water supply device starts operation to supply hot water, and the system control device 15 starts controlling the number of operating units. This control of the number of operating units will be explained based on the flowchart in Figure 3. In the figure, Si (i = 1, 2, ...) represents a step.

[0030] When control of the number of operating units is started, the number N of sub-water heating units included in the candidate units for operation is obtained in S1, and the process proceeds to S2. Then, in S2, since only the main water heating unit has started operating immediately after the start of hot water supply operation, the number n of operating sub-water heating units is set to zero, and the process proceeds to S3.

[0031] In S3, it is determined whether the heating capacity of the water heater that last started operating has reached or exceeded a specified value. This is the step for determining the additional operating conditions of the sub-water heater. System control device 15 acquires various data related to the hot water operation from control units 40 of each of multiple water heaters 11-14, and determines the heating capacity of water heaters 11-14. The water heater that last started operating is the main water heater if only the main water heater is operating, and if a sub-water heater is also operating, it is the sub-water heater that started operating last (has the lowest operating priority) among the operating sub-water heaters.

[0032] If the determination in S3 is Yes, the process proceeds to S4. Then, in S4, it is determined whether the number n of operating sub-water heating devices is smaller than the number N of sub-water heating devices. This is the step to determine whether there are any inactive sub-water heating devices that can be additionally operated. If the determination in S4 is Yes, the process proceeds to S5, where one inactive sub-water heating device is additionally operated in S5, and the process proceeds to S6. Then, in S6, the number n of operating sub-water heating devices is incremented by 1, and the process proceeds to S7. At this time, the control unit 40 of the sub-water heating device that received the additional operation command begins operation by opening the water supply valve 30 of that sub-water heating device.

[0033] On the other hand, if the determination in S3 is No, the sub-water heating device is not additionally operated and the process proceeds to S7. Also, if the determination in S4 is No, there is no sub-water heating device that is not yet in operation and can be additionally operated, so the process proceeds to S7 without additionally operating the sub-water heating device.

[0034] In S7, it is determined whether the water supply flow rate of the water heater that was last activated among the currently operating water heaters has fallen below the activation flow rate. If the amount of hot water usage decreases, the water flow rate of the currently operating water heaters will also decrease, so to compensate for this decrease, the opening of the hot water outlet flow rate adjustment valve 39 of the water heater that was last activated is preferentially adjusted, reducing the heating capacity. If the water supply flow rate falls below the activation flow rate, stable hot water operation will become difficult, so this is the step where the operation stop conditions are determined to stop the water heater that was last activated.

[0035] If the determination in S7 is No, the process returns to S3. If the determination in S7 is Yes, the process proceeds to S8, where the operation of the water heater that last started operation is stopped in S8, and the process proceeds to S9. Control unit 40 of the water heater that has been instructed to stop operation by system control device 15 closes water supply valve 30 of that water heater to stop operation.

[0036] In S9, it is determined whether the number n of operating sub-water heating devices is zero. If the determination in S9 is No (n>0), the process proceeds to S10, where the number n of operating sub-water heating devices is decremented by 1, and since at least the main water heating device is operating, the process returns to S3. On the other hand, if the determination in S9 is Yes (n=0), the operation of the main water heating device was stopped in S8, so the process proceeds to S11. Then, in S11, hot water supply operation is terminated and control of the number of operating devices is terminated.

[0037] Next, an example of the transition of heating capacity during hot water supply operation will be described with reference to FIG. After hot water supply operation begins in state (a) with only the main water heater operating, the heating capacity is increased and when the main water heater reaches the specified maximum heating capacity (additional operation conditions are met), one sub-water heater (first sub-water heater) is additionally operated, transitioning to state (b).Furthermore, it is possible to increase the heating capacity through state (c) where the second sub-water heater is additionally operated upon the satisfaction of additional operation conditions, and then the third sub-water heater is additionally operated, up to state (d) where all of the multiple water heaters 11-14 are operating at maximum heating capacity.

[0038] On the other hand, if the hot water supply flow rate decreases from state (d), for example, the heating capacity is preferentially reduced by reducing the opening of the hot water outlet flow rate adjustment valve 39 of the hot water supply device (third sub-hot water supply device) that was last activated among the operating hot water supply devices. Then, when the water supply flow rate of this third sub-hot water supply device falls below the operation start flow rate (when the operation stop condition is met), operation is stopped. By further reducing the heating capacity and reducing the heating capacity in the reverse order of the operation start order to reduce the number of operating units, the system transitions to state (a) via states (c) and (b), and then to state (a). When the water supply flow rate of the main hot water supply device falls below the operation start flow rate, hot water supply operation is terminated. Furthermore, even if the amount of hot water usage increases or decreases during hot water supply, the heating capacity of the hot water supply device that was last activated among the operating hot water supply devices is adjusted, and the number of operating units is changed according to the additional operation condition and operation stop condition.

[0039] In the state (d) where the linked hot water supply system 10 supplies hot water at maximum heating capacity, the opening of the hot water outlet flow control valve 39 of the hot water supply device (third sub-hot water supply device) that was last activated is at its maximum, and the openings of the hot water outlet flow control valves 39 of the multiple hot water supply devices activated before that are also at their maximums. Therefore, there should be no difference in the water flow rates of the active hot water supply devices. Taking advantage of this, the system control device 15 determines whether the water inlet filter 33 is clogged by comparing the water flow rates of the active hot water supply devices when the opening of the hot water outlet flow control valve 39 of the last activated hot water supply device is at its maximum. The operation remote control 15a then notifies the user of the hot water supply device whose water inlet filter 33 is determined to be clogged, for example, by displaying or outputting a sound.

[0040] The process by which the system control device 15 determines whether the inlet filter 33 is clogged will be described with reference to the flowchart of FIG. When hot water supply operation starts, the blockage determination is started, and in S21 it is determined whether the opening of the hot water outlet flow rate adjustment valve 39 (water volume adjustment valve) of the hot water supply device that last started operation has reached its maximum. Since it is preferable to determine blockage when the water flow rate is stable, it may be determined that a predetermined time has passed since the opening of the hot water outlet flow rate adjustment valve 39 reached its maximum. If the determination in S21 is No, the process returns to S21, and if the determination in S21 is Yes, the process proceeds to S22.

[0041] In S22, the water flow rate of each of all operating water heating devices is acquired, and the process proceeds to S23. Then, in S23, a reference value is set for the water heating device to be determined for blockage based on the acquired water flow rate, and the process proceeds to S24. For example, the reference value for a sub-water heating device is set to the water flow rate of the water heating device that was just before the start of operation, and for the main water heating device, the reference value is set to the water flow rate of the sub-water heating device that was last started up. The reference value may be, for example, the average or median water flow rate of operating water heating devices during the most recent measurement period, or the average or median water flow rate of other water heating devices excluding the water heating device to be determined for blockage during the most recent measurement period. The water heating device to be determined for blockage is set one by one from the water heating devices that are candidates for operation.

[0042] In S24, it is determined whether the water flow rate of the water heater to be determined to be clogged is equal to or greater than a reference value -α (α is a predetermined tolerance value set in advance). If the determination in S24 is Yes, the process proceeds to S25, where the water heater to be determined to be clogged is left as a candidate for operation as a water heater whose water inlet filter 33 is not clogged, and then the process proceeds to S27. On the other hand, if the determination in S24 is No, the process proceeds to S26, where the water heater to be determined to be clogged is removed from the candidate for operation as a water heater whose water inlet filter 33 is clogged, and then the process proceeds to S27.

[0043] In S27, it is determined whether the blockage determination by comparing the water flow rate has been completed for all of the operating water heaters. If the determination in S27 is No, the process returns to S23, and if the determination in S27 is Yes, the blockage determination ends.

[0044] For example, when comparing with a standard value set based on the specifications of the water heater, the influence of the water supply pressure is imposed, but since the water flow rate is determined by comparing the actual water flow rate with a standard value set according to the installation environment, the influence of the water supply pressure can be eliminated. Also, before the blockage of water inlet filter 33 progresses to the point where the water heater becomes inoperable, the blockage of water inlet filter 33 can be detected and maintenance can be performed.

[0045] System control device 15 excludes water heaters determined to have clogged water inlet filters 33 from the list of operating candidates and controls the number of operating units during hot water supply operation. This prevents a situation in which the additional operating conditions are not met because the water flow rate is difficult to increase due to clogged water inlet filters 33, and allows the number of operating units to be increased to increase heating capacity. Furthermore, if shut-off valves are installed between water supply pipe 1 and the water inlet filters 33 of each of multiple water heaters 11-14, maintenance can be performed by closing the shut-off valve of a water heater determined to have clogged water inlet filters 33 while allowing hot water use.

[0046] The operation and effects of the linked hot water supply system 10 will now be described. Each of the multiple water heaters 11-14 of the linked hot water supply system 10 has a water flow rate detection means for detecting the flow rate of clean water introduced from the water supply pipe 1. When the multiple water heaters 11-14 are operating simultaneously, the system control device 15 (control means) compares the water flow rates of the operating water heaters 11-14 to determine whether or not the water inlet filters 33 provided at the clean water inlet portions 29a in the water supply passages 29 of the multiple water heaters 11-14 are clogged.

[0047] Therefore, by comparing the water flow rates of multiple hot water heaters 11-14 that are operating simultaneously, system control device 15 can determine that water inlet filter 33 of a hot water heater with a small water flow rate is clogged. Then, it is possible to prompt maintenance of a hot water heater determined to have clogged water inlet filter 33.

[0048] Each of the multiple water heaters 11-14 in the linked hot water supply system 10 is equipped with a hot water outlet flow rate adjustment valve 39 (water volume adjustment means). If the opening degree of the hot water outlet flow rate adjustment valve 39 of the hot water heater that last started operating among the multiple operating water heaters 11-14 is at its maximum, then the opening degrees of the hot water outlet flow rate adjustment valves 39 of all of the operating water heaters 11-14 will be at their maximum, and the water flow rates of the multiple operating water heaters 11-14 should be equal. Using this, it is possible to determine whether the water inlet filter 33 is clogged for the multiple operating water heaters 11-14.

[0049] System control device 15 excludes water heaters determined to have clogged water inlet filters 33 from the list of operation candidates and prevents them from operating. This prevents problems such as insufficient heating capacity due to the additional operation condition not being met due to clogged water inlet filters 33, and allows the number of operating units to be increased to increase heating capacity according to the hot water supply flow rate. Furthermore, maintenance of water heaters determined to have clogged water inlet filters can be performed without interfering with hot water supply by other water heaters.

[0050] The determination of blockage of water inlet filter 33 may be made when the water flow rate is less than a predetermined ratio of the reference value. When adjusting the hot water outlet flow rate control valve 39 of the hot water heater that was last activated so that the heating capacities of multiple operating hot water heaters are equal, it is also possible to determine blockage of water inlet filter 33 without considering the non-activated hot water heaters that are candidates for activation. In addition, those skilled in the art can implement the above-described embodiment in various modified forms without departing from the spirit of the present invention, and the present invention includes such modified forms. [Explanation of symbols]

[0051] 1: Water supply piping 2: Hot water supply piping 10: Connected hot water system 11-14: Hot water supply equipment 15: System control device (control means) 15a: Operation remote control 21: Combustion section 22:Heat exchange section 23: Water supply section 24: Tap area 25: Burner 25a to 25d: 1st to 4th combustion sections 25e~25h: On-off valve 26: Fuel adjustment valve 27: Combustion fan 28:Ignition device 29:Water supply passage 29a: Introduction 30: Water supply valve 31: Water supply temperature sensor 32: Water supply flow sensor 33: Inlet filter 34: Hot water passage 35: Bypass passage 36: Bypass flow control valve 37: First hot water outlet temperature sensor 38: Second hot water outlet temperature sensor 39: Hot water flow rate adjustment valve (water volume adjustment means) 40: Control section F1~Fm: Hot water tap

Claims

1. A linked hot water supply system includes a plurality of combustion-type hot water supply devices installed in parallel between a water supply pipe and a hot water supply pipe, and a control means for changing the number of the hot water supply devices to be operated in order to adjust the heating capacity according to the amount of hot water used. Each of the plurality of hot water supply devices has a water flow rate detection means for detecting the flow rate of clean water introduced from the water supply pipe, and a water inlet filter provided at an inlet portion of the clean water from the water supply pipe, A linked hot water supply system characterized in that the control means determines whether the water inlet filters equipped in each of the multiple hot water supply devices are clogged by comparing the water flow rate of the operating hot water supply devices when the multiple hot water supply devices are operating simultaneously.

2. Each of the plurality of hot water supply devices has a water flow rate adjusting means for adjusting the amount of water flowing during operation, The linked hot water supply system of claim 1, characterized in that the control means compares the water flow rates of the multiple hot water supply devices currently in operation when the opening degree of the water flow adjustment means of the hot water supply device that was last operated among the multiple hot water supply devices currently in operation is at its maximum.

3. The linked hot water supply system according to claim 1 or 2, characterized in that the control means excludes from the candidates for operation any hot water supply device among the plurality of hot water supply devices whose water inlet filter is determined to be clogged.

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