Connected hot water system

Abstract

To provide a technique for suppressing a decrease in water heating capacity of an entire connected hot water system.SOLUTION: A connected hot water system includes: a plurality of hot water devices aligned in parallel between a water supply pipe and a water outlet pipe; and a connected control device for controlling an operation of the plurality of hot water devices. Each of the plurality of hot water devices includes: a burner for heating water flown from the water supply pipe to the hot water device as needed; a flow rate adjustment valve for adjusting a flow rate of the water flown from the water supply pipe to the hot water device; a flow rate sensor for detecting the flow rate of the water flown from the water supply pipe to the hot water device; and an individual control device capable of communicating with the connected control device. When the individual control device cannot communicate with the connected control device, the individual control device can operate in a disconnection operation mode. In the disconnection operation mode, when the flow rate sensor does not detect water supply, the individual control device stands by as a first opening degree in a state where an opening of the flow rate adjustment valve is smaller than full opening and larger than full closing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a linked hot water system. [Background technology]

[0002] Patent Document 1 discloses a linked hot water supply system including multiple hot water supply devices arranged in parallel between a water supply pipe and a hot water outlet pipe, and a linked control device that controls the operation of the multiple hot water supply devices. Each of the multiple hot water supply devices includes a burner that heats water flowing from the water supply pipe to the hot water supply device as needed, a flow control valve that adjusts the flow rate of water flowing from the water supply pipe to the hot water supply device, a flow sensor that detects the flow rate of water flowing from the water supply pipe to the hot water supply device, and an individual control device that can communicate with the linked control device. The individual control device can operate in a disconnected operation mode when it cannot communicate with the linked control device. In the disconnected operation mode, if the flow sensor does not detect water flow, the individual control device waits with the flow control valve fully closed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-288624 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned linked hot water supply system, water will no longer flow from the water supply pipe to a hot water supply device operating in the disconnection operation mode, making that device unable to supply hot water. Therefore, if some hot water supply devices are unable to communicate with the linked control device, this may result in a decrease in the hot water supply capacity of the linked hot water supply system as a whole. This specification provides a technology that can suppress a decrease in the hot water supply capacity of the linked hot water supply system as a whole, even if some hot water supply devices are unable to communicate with the linked control device. [Means for solving the problem]

[0005] In a first aspect, the linked hot water supply system may include a plurality of hot water supply devices arranged in parallel between a water supply pipe and a hot water outlet pipe, and a linked control device that controls the operation of the plurality of hot water supply devices. Each of the plurality of hot water supply devices may include a burner that heats water flowing from the water supply pipe to the hot water supply device as needed, a flow control valve that adjusts the flow rate of water flowing from the water supply pipe to the hot water supply device, a flow sensor that detects the flow rate of water flowing from the water supply pipe to the hot water supply device, and an individual control device that can communicate with the linked control device. The individual control device may be capable of operating in a disconnected operation mode when it is unable to communicate with the linked control device. In the disconnected operation mode, when the flow sensor does not detect water flow, the individual control device may wait with the flow control valve set to a first opening degree that is smaller than fully open and larger than fully closed.

[0006] In the above-mentioned linked hot water supply system, a water heater operating in the disconnection operation mode waits with the flow control valve set to a first opening degree that is greater than the fully closed state, so that water continues to flow into the water heater from the water supply pipe and the water heater can be used to supply hot water. Therefore, when some water heaters cannot communicate with the linked control device, a decrease in the hot water supply capacity of the linked hot water supply system as a whole can be prevented.

[0007] In a typical linked hot water supply system, water heaters that operate in accordance with instructions from a link control device stand by with their flow control valves fully open or fully closed. Specifically, in a linked hot water supply system, of the water heaters that are not yet operating, the one that the link control device wants to operate next (for example, if none of the multiple water heaters are operating, the one that it wants to operate first) stands by with its flow control valve fully open, and the other water heaters that are not yet operating stand by with their flow control valves fully closed. This is so that, when the flow rate of the entire linked hot water supply system increases, water is concentrated into the water heater that is to operate next (for example, the water heater that it wants to operate first) so that that water heater can quickly start supplying hot water. If a water heating device operating in disconnection operation mode were to wait with the flow rate adjustment valve fully open, when the flow rate of the entire connected hot water system increased, the increase in the flow rate of water flowing to the water heating device to be operated next (for example, the water heating device to be operated first) would be small, and the water heating device would not be able to start supplying hot water promptly. According to the above configuration, a water heating device operating in disconnection operation mode is on standby with the flow rate adjustment valve set to a first opening rate that is smaller than fully open, so when the flow rate of the entire connected hot water system increased, the flow rate of water flowing to the water heating device to be operated next (for example, the water heating device to be operated first) can be significantly increased, and the water heating device can start supplying hot water promptly.

[0008] In a second aspect, the individual control device of the first aspect may be configured to ignite the burner when the flow rate detected by the flow rate sensor reaches or exceeds a predetermined ignition flow rate, and the first opening degree may be smaller than the opening degree corresponding to the ignition flow rate.

[0009] According to the above configuration, a water heating device operating in disconnection operation mode waits with the flow control valve set to a sufficiently small opening, so that when the flow rate of the entire connected water heating system increases, the connected control device can more significantly increase the flow rate of water flowing to the water heating device that it wants to operate next (for example, the water heating device that it wants to operate first), and hot water supply by that water heating device can be started quickly.

[0010] In a third aspect, in the second aspect, when the flow rate sensor detects water flow while the individual control device is waiting with the flow rate control valve open to the first opening rate, the individual control device may increase the opening rate of the flow rate control valve from the first opening rate to a second opening rate that is larger than the opening rate corresponding to the ignition flow rate.

[0011] According to the above configuration, when the flow rate of the entire connected hot water supply system increases, the flow rate of the hot water supply device operating in the disconnection operation mode can be increased, so that hot water supply by the hot water supply device operating in the disconnection operation mode can be started quickly.

[0012] In a fourth aspect, in the third aspect, the individual control device may further increase the opening of the flow rate adjustment valve when the flow rate detected by the flow rate sensor increases accordingly when the opening of the flow rate adjustment valve is increased to the second opening. The individual control device may maintain the opening of the flow rate adjustment valve as it is when the flow rate detected by the flow rate sensor does not increase accordingly when the opening of the flow rate adjustment valve is increased to the second opening.

[0013] If the flow rate that can be flowed in the linked hot water supply system is smaller than the flow rate that can be flowed at the hot water supply location (i.e., if the linked hot water supply system is a bottleneck), increasing the opening of the flow control valve will increase the flow rate detected by the flow sensor. Conversely, if the flow rate that can be flowed in the linked hot water supply system is greater than the flow rate that can be flowed at the hot water supply location (i.e., if the linked hot water supply system is not a bottleneck), increasing the opening of the flow control valve will not increase the flow rate detected by the flow sensor. With the above configuration, the opening of the flow control valve can be increased to an opening that does not cause the linked hot water supply system to become a bottleneck.

[0014] In a fifth aspect, in the fourth aspect, the individual control device may increase the opening degree of the flow control valve when the flow rate detected by the flow sensor increases while maintaining the opening degree of the flow control valve at the second opening degree.

[0015] The flow rate detected by the flow sensor increases even though the opening of the flow control valve is maintained when the flow rate that can be flowed in the connected hot water supply system is greater than the flow rate that can be flowed at the hot water supply location (i.e., the connected hot water supply system is not a bottleneck) and the flow rate that can be flowed at the hot water supply location increases. According to the above configuration, in such a case, the opening of the flow control valve is increased, so the opening of the flow control valve can be increased in accordance with the increase in the flow rate that can be flowed at the hot water supply location.

[0016] In a sixth aspect, in the fourth or fifth aspect, the individual control device may reduce the opening of the flow control valve when the flow rate detected by the flow sensor decreases while the opening of the flow control valve is maintained at the second opening rate.

[0017] The flow rate detected by the flow sensor decreases even though the opening of the flow control valve is maintained when the flow rate that can be flowed in the connected hot water supply system is greater than the flow rate that can be flowed at the hot water supply location (i.e., the connected hot water supply system is not a bottleneck) and the flow rate that can be flowed at the hot water supply location decreases. According to the above configuration, in such a case, the opening of the flow control valve is decreased, so the opening of the flow control valve can be decreased in accordance with the decrease in the flow rate that can be flowed at the hot water supply location.

[0018] In a seventh aspect, in any one of the first to sixth aspects, each of the plurality of water heating devices may further include an alarm device. When the individual control device cannot communicate with the linked control device, the individual control device may notify the user via the alarm device that the individual control device is operating in the disconnection operation mode.

[0019] According to the above configuration, if communication with the connection control device becomes impossible and the device is operating in the disconnection operation mode, the user can be notified immediately. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing the configuration of a linked hot water supply system 100 according to an embodiment. [Figure 2] 1 is a diagram showing a configuration of a water heater 1 according to an embodiment. [Figure 3] 4 is a flowchart of a mode determination process of a water heater 1 according to the embodiment. [Figure 4] 4 is a flowchart of a disconnection operation process of the water heater 1 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] (Example) As shown in FIG. 1 , the interconnected hot water supply system 100 of this embodiment includes a plurality of hot water supply devices 1. The plurality of hot water supply devices 1 are arranged in parallel between a water supply pipe 110 and a hot water outlet pipe 120 so that water is supplied from the water supply pipe 110 and hot water is delivered to the hot water outlet pipe 120. Each hot water supply device 1 is connected to the water supply pipe 110 via a corresponding water supply connecting pipe 112. Water such as tap water is supplied to the water supply pipe 110 from a water supply source (not shown). Each hot water supply device 1 is connected to the hot water outlet pipe 120 via a corresponding hot water outlet connecting pipe 122. The hot water outlet pipe 120 delivers hot water to a hot water supply location such as a bathroom or a kitchen. The hot water outlet pipe 120 is provided with a water faucet 124 such as a faucet or shower (for simplicity's sake, only a single water faucet 124 is shown in FIG. 1 ). The plurality of hot water supply devices 1 are also connected to a gas supply pipe 130 via a corresponding gas supply connecting pipe 132. Fuel gas such as city gas is supplied from a gas supply source (not shown) to gas supply pipe 130. As a result, fuel gas is supplied from gas supply pipe 130 to multiple water heating devices 1. Furthermore, multiple water heating devices 1 can communicate with each other via communication cable 140.

[0022] (Configuration of water heater 1) As shown in FIG. 2, the water heater 1 includes a burner 3, a fan 4, a gas-liquid heat exchanger 6, an inlet pipe 7, an outlet pipe 8, a boiler body 10, a control device 30, an input device 32, and a display device 34. The burner 3 and the gas-liquid heat exchanger 6 are housed inside the boiler body 10. The gas-liquid heat exchanger 6 is disposed above the burner 3. The fan 4 supplies air for combustion from the bottom of the boiler body 10. The combustion gas from the burner 3 flows from bottom to top inside the boiler body 10, heating the gas-liquid heat exchanger 6. The combustion exhaust gas after heating the gas-liquid heat exchanger 6 is discharged from an exhaust port 10a provided at the top of the boiler body 10.

[0023] An inlet pipe 7 and an outlet pipe 8 are connected to the gas-liquid heat exchanger 6. The upstream end of the inlet pipe 7 is connected to a water supply connecting pipe 112. The downstream end of the outlet pipe 8 is connected to a hot water outlet connecting pipe 122. The hot water supply device 1 is also provided with a bypass pipe 9 that bypasses the gas-liquid heat exchanger 6 and connects the inlet pipe 7 and the outlet pipe 8, and a bypass servo 24 that adjusts the opening of the bypass pipe 9 to change the bypass ratio (the ratio of the flow rate of water supplied to the bypass pipe 9 to the flow rate of water supplied to the gas-liquid heat exchanger 6). Water supplied from the water supply connecting pipe 112 is supplied to the gas-liquid heat exchanger 6 from the inlet pipe 7 and heated in the gas-liquid heat exchanger 6 to become high-temperature hot water. The high-temperature hot water flowing out of the gas-liquid heat exchanger 6 is then mixed with low-temperature water that has flowed from the inlet pipe 7 to the bypass pipe 9, where the temperature is adjusted, and then sent out from the outlet pipe 8 to the hot water outlet connecting pipe 122.

[0024] The burners 3 include a first burner 3a, a second burner 3b, and a third burner 3c. Fuel gas is supplied to the burners 3 through a gas pipe 11. The upstream end of the gas pipe 11 is connected to a gas supply connection pipe 132. The gas pipe 11 is provided with, in order from the upstream side, a main gas solenoid valve 12, a gas proportional valve 13, and switching gas solenoid valves 14a, 14b, and 14c. When the main gas solenoid valve 12 is opened, fuel gas is supplied to the burners 3, and when the main gas solenoid valve 12 is closed, the supply of fuel gas to the burners 3 is cut off. The gas proportional valve 13 adjusts the amount of fuel gas supplied to the burners 3. The switching gas solenoid valves 14a, 14b, and 14c are provided corresponding to the first burner 3a, the second burner 3b, and the third burner 3c, respectively. When the switching gas solenoid valves 14a, 14b, 14c are opened, fuel gas is supplied to the corresponding first burner 3a, second burner 3b, and third burner 3c, and when the switching gas solenoid valves 14a, 14b, and 14c are closed, the supply of fuel gas to the corresponding first burner 3a, second burner 3b, and third burner 3c is cut off. The combustion amount range of the burner 3 can be changed by switching each of the switching gas solenoid valves 14a, 14b, and 14c between the open and closed states.

[0025] In the water heater 1, the combustion amount range of the burner 3 can be switched between three stages. The first combustion amount range, which has the lowest combustion amount, corresponds to a state in which the first burner 3a is burning and the second burner 3b and the third burner 3c are not burning. The second combustion amount range, which has a combustion amount higher than the first combustion amount range, corresponds to a state in which the first burner 3a and the second burner 3b are burning and the third burner 3c is not burning. The third combustion amount range, which has a combustion amount higher than the second combustion amount range, corresponds to the highest combustion amount and corresponds to a state in which the first burner 3a, the second burner 3b, and the third burner 3c are all burning. In the water heater 1, the rotation speed of the fan 4 is predetermined according to the current combustion amount range of the burner 3 and the combustion amount within that combustion amount range, and the fan 4 rotates at the predetermined rotation speed.

[0026] Near the burner 3, there are provided an ignition plug 16 for igniting the burner 3 and a flame rod 17 for detecting the combustion flame of the burner 3. There is also provided an igniter 15 for applying a high voltage to the ignition plug 16 to generate a spark discharge.

[0027] The inlet pipe 7 is provided with a flow rate sensor 18 that detects the flow rate of water supplied to the inlet pipe 7 (= the flow rate of hot water flowing out from the outlet pipe 8), a flow rate adjustment valve 19 that adjusts the flow rate of water supplied to the inlet pipe 7, and a supply water temperature sensor 25 that detects the temperature of the water supplied to the inlet pipe 7. The outlet pipe 8 is provided with a heat exchanger outlet temperature sensor 21 that detects the temperature of the water flowing in from the gas-liquid heat exchanger 6, and an outlet hot water temperature sensor 23 that detects the temperature of the water flowing out from the outlet pipe 8.

[0028] The control device 30 controls the operation of the hot water supply apparatus 1. The control device 30 is an electronic unit composed of a microcomputer, memory, etc. The control device 30 operates according to a program stored in the memory. Detection signals from the flame rod 17, flow sensor 18, feedwater temperature sensor 25, heat exchanger outlet temperature sensor 21, and outlet hot water temperature sensor 23 are input to the control device 30. The control device 30 outputs control signals to control the operation of the fan 4, main gas solenoid valve 12, gas proportional valve 13, switching gas solenoid valves 14a, 14b, and 14c, igniter 15, flow control valve 19, and bypass servo 24. The control device 30 is also connected to an input device 32 and a display device 34. The input device 32 includes, for example, multiple input switches. A user of the hot water supply apparatus 1 can input various settings for the operation of the hot water supply apparatus 1 via the input device 32. The display device 34 includes, for example, a liquid crystal display. Display device 34 can notify the user of water heating apparatus 1 of various information related to the operation of water heating apparatus 1. Furthermore, control device 30 is connected to communication cable 140. Control device 30 can communicate bidirectionally with control device 30 of other water heating apparatus 1 via communication cable 140.

[0029] (Ignition and extinguishing treatment) The control device 30 constantly monitors the flow rate detected by the flow rate sensor 18. When the flow rate detected by the flow rate sensor 18 becomes equal to or greater than a predetermined ignition flow rate (for example, 2.7 L / min) while the burner 3 is not burning, the control device 30 executes the ignition process for the burner 3. That is, the control device 30 drives the fan 4, opens the main gas solenoid valve 12 and the switching gas solenoid valve 14a, drives the igniter 15, ignites the first burner 3a, and starts combustion in the burner 3.

[0030] While the burner 3 is burning, the control device 30 adjusts the opening and closing of the switching gas solenoid valves 14a, 14b, 14c, the opening of the gas proportional valve 13, the rotation speed of the fan 4, and the opening of the bypass servo 24 so that the temperature detected by the heat exchanger outlet temperature sensor 21 becomes a predetermined target temperature (e.g., 60°C) and the temperature detected by the hot water outlet temperature sensor 23 becomes the hot water supply set temperature set by the user.

[0031] Furthermore, when the flow rate detected by the flow rate sensor 18 falls below a predetermined extinguishing flow rate (for example, 2.0 L / min) while the burner 3 is burning, the control device 30 executes a process to extinguish the burner 3. That is, the control device 30 stops driving the fan 4 and closes the main gas solenoid valve 12 and the switching gas solenoid valves 14a, 14b, and 14c to extinguish the burner 3 and terminate combustion of the burner 3.

[0032] (standalone operation mode and linked operation mode) The water heating apparatus 1 can select either an independent operation mode or a connected operation mode as its operation mode. In the independent operation mode, the water heating apparatus 1 operates without communicating with other water heating apparatuses 1. In the connected operation mode, the water heating apparatus 1 operates using communication with other water heating apparatuses 1. When the connected operation mode is selected as its operation mode, the water heating apparatus 1 can select either a master operation mode or a slave operation mode as its operation mode. In the master operation mode, the water heating apparatus 1 operates independently of the other water heating apparatuses 1. In the slave operation mode, the water heating apparatus 1 operates subordinately to the other water heating apparatuses 1. Specifically, a water heating apparatus 1 for which the master operation mode is selected (also simply referred to as the master water heating apparatus 1) transmits an operation instruction to a water heating apparatus 1 for which the slave operation mode is selected (also simply referred to as the slave water heating apparatus 1). The slave water heating apparatus 1 operates according to the operation instruction received from the master water heating apparatus 1. That is, when the master unit operation mode is selected in the water heating apparatus 1, the control device 30 of the water heating apparatus 1 functions both as a linked control device that controls the operation of each of the multiple water heating apparatuses 1 and as an individual control device that controls the operation of the water heating apparatus 1 itself. Furthermore, when the slave unit operation mode is selected in the water heating apparatus 1, the control device 30 of the water heating apparatus 1 does not function as a linked control device that controls the operation of each of the multiple water heating apparatuses 1, but functions only as an individual control device that controls the operation of the water heating apparatus 1 itself. Whether the operation mode of the water heating apparatus 1 is to be the standalone operation mode or the linked operation mode can be input in advance via the input device 32. Furthermore, when the linked operation mode is selected as the operation mode, whether the operation mode of the water heating apparatus 1 is to be the master unit operation mode or the slave unit operation mode can be input in advance via the input device 32.

[0033] (Mode determination process) When water heating apparatus 1 is powered on, controller 30 executes a mode determination process shown in FIG.

[0034] In S2, controller 30 determines whether or not the operation mode of water heating apparatus 1 is the connected operation mode. If the operation mode of water heating apparatus 1 is the stand-alone operation mode (NO), the process proceeds to S4.

[0035] In S4, the controller 30 executes processing in the isolated operation mode. In the isolated operation mode, the controller 30 stands by with the flow rate adjustment valve 19 fully open.

[0036] If the mode setting of water heating apparatus 1 is the connected operation mode in S2 (if YES), the process proceeds to S6. In S6, controller 30 determines whether the operation mode of water heating apparatus 1 is the master unit operation mode. If the operation mode is the master unit operation mode (if YES), the process proceeds to S8.

[0037] In S8, control device 30 executes master unit operation processing to operate water heating apparatus 1 in the master unit operation mode. That is, control device 30 uses communication with water heating apparatus 1 that is a slave unit to determine whether flow rate adjustment valve 19 of each water heating apparatus 1 is fully open or fully closed, and instructs water heating apparatus 1 that is a slave unit to wait with flow rate adjustment valve 19 fully open or fully closed.

[0038] If the operation mode is the slave operation mode in S6 (if NO), the process proceeds to S10. In S10, control device 30 determines whether or not communication with master water heating apparatus 1 is possible. If communication with master water heating apparatus 1 is possible (if YES), the process proceeds to S12. In S12, control device 30 executes slave operation processing to operate water heating apparatus 1 in the slave operation mode. That is, control device 30 uses communication with master water heating apparatus 1 to wait with flow rate adjustment valve 19 fully open or fully closed in accordance with instructions from master water heating apparatus 1.

[0039] If communication with water heating apparatus 1, which is the parent unit, is not possible in S10 (NO), the process proceeds to S14. In S14, controller 30 executes the disconnection operation process shown in Fig. 4 to operate water heating apparatus 1 in the disconnection operation mode.

[0040] (Disconnection operation processing) As shown in FIG. 4, in S20, the control device 30 notifies the user via the display device 34 that it is operating in the disconnection operation mode.

[0041] In S22, the control device 30 waits with the opening of the flow rate control valve 19 set to a first opening. The first opening is an opening greater than 0% and less than 100%, where 0% is the opening when fully closed and 100% is the opening when fully open. The first opening is also smaller than the opening corresponding to the ignition flow rate (e.g., 2.7 L / min) (i.e., the opening at which the flow rate of water flowing through the flow rate control valve 19 becomes the ignition flow rate when water is supplied to the flow rate control valve 19 at a sufficiently large supply pressure with the flow rate control valve 19 set to that opening).

[0042] In S24, control device 30 waits until water flow starts in water heating device 1. Control device 30 determines that water flow has started when the flow rate detected by flow rate sensor 18 remains at or above a predetermined water flow detection flow rate (e.g., 1.0 L / min) for a predetermined time (e.g., 1 minute) or more. Control device 30 may also determine that water flow has started when the integrated flow rate since water flow sensor 18 detected water flow remains at or above a predetermined water flow detection integrated flow rate (e.g., 1.0 L). If it is determined in S24 that water flow has started (YES), the process proceeds to S26.

[0043] In S26, the controller 30 increases the opening of the flow rate adjustment valve 19 by a predetermined opening increase amount (for example, 5%).

[0044] In S28, the control device 30 determines whether the flow rate detected by the flow sensor 18 has increased by a predetermined flow rate (e.g., 0.2 L / min) or more. If it is determined that the detected flow rate has increased by the predetermined flow rate (e.g., 0.2 L / min) or more (YES), the process returns to S26, and the control device 30 further increases the opening of the flow rate adjustment valve 19. If it is not determined in S28 that the detected flow rate has increased by the predetermined flow rate (e.g., 0.2 L / min) or more (NO), the process proceeds to S30.

[0045] If, at the time of executing the process of S26, the flow rate that can be flowed through the linked hot water supply system 100 is smaller than the flow rate that can be flowed through the tap 124 of the hot water outlet pipe 120 (i.e., if the linked hot water supply system 100 is a bottleneck), increasing the aperture of the flow adjustment valve 19 in S26 will increase the flow rate detected by the flow sensor 18 in S28. Conversely, if, at the time of executing the process of S26, the flow rate that can be flowed through the linked hot water supply system 100 is greater than the flow rate that can be flowed through the tap 124 of the hot water outlet pipe 120 (i.e., if the linked hot water supply system 100 is not a bottleneck), increasing the aperture of the flow adjustment valve 19 in S26 will not increase the flow rate detected by the flow sensor 18 in S28. For this reason, by repeatedly executing the processes of S26 and S28, the control device 30 can increase the aperture of the flow adjustment valve 19 to an aperture at which the linked hot water supply system 100 does not become a bottleneck.

[0046] In S30, the control device 30 waits until a predetermined time (for example, one minute) has elapsed.

[0047] In S32, the control device 30 determines whether the flow rate detected by the flow sensor 18 has increased by a predetermined amount (e.g., 0.2 L / min) or more. If it is determined that the detected flow rate has increased by a predetermined amount (e.g., 0.2 L / min) or more (YES), the process proceeds to S34. In S34, the control device 30 increases the opening of the flow control valve 19 by a predetermined increase in opening (e.g., 5%). After S34, the process returns to S30. If it is not determined in S32 that the detected flow rate has increased by a predetermined amount (e.g., 0.2 L / min) or more (NO), the process proceeds to S36.

[0048] Because the processing of S32 is performed after the processing of S30, the opening degree of the flow rate adjustment valve 19 has not been increased or decreased immediately before the processing of S32 is performed. For this reason, the flow rate detected by the flow rate sensor 18 increases in S32 when the flow rate that can be flowed by the linked hot water supply system 100 is greater than the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120 (i.e., the linked hot water supply system 100 is a bottleneck) and the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120 has increased. For this reason, by performing the processing of S32 and S34, the control device 30 can increase the opening degree of the flow rate adjustment valve 19 in accordance with the increase in the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120.

[0049] In S36, the control device 30 determines whether the flow rate detected by the flow sensor 18 has decreased by a predetermined amount (e.g., 0.2 L / min) or more. If it is determined that the detected flow rate has decreased by a predetermined amount (e.g., 0.2 L / min) or more (YES), the process proceeds to S38. In S38, the control device 30 reduces the opening of the flow rate adjustment valve 19 by a predetermined amount (e.g., 5%). After S38, the process returns to S30. If it is not determined in S36 that the detected flow rate has decreased by a predetermined amount (e.g., 0.2 L / min) or more (NO), the process proceeds to S40.

[0050] Because the processing of S36 is performed after the processing of S30 and S32, the opening degree of the flow rate adjustment valve 19 has not been increased or decreased immediately before the processing of S36 is performed. For this reason, the flow rate detected by the flow rate sensor 18 decreases in S36 when the flow rate that can be flowed by the linked hot water supply system 100 is greater than the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120 (i.e., the linked hot water supply system 100 is not a bottleneck) and the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120 has decreased. For this reason, by performing the processing of S36 and S38, the control device 30 can reduce the opening degree of the flow rate adjustment valve 19 in accordance with the decrease in the flow rate that can be flowed at the faucet 124 of the hot water outlet pipe 120.

[0051] In S40, controller 30 determines whether water flow has ended in water heating apparatus 1. Controller 30 determines that water flow has ended when the flow rate detected by flow rate sensor 18 remains below a predetermined water flow detection flow rate (e.g., 1.0 L / min) for a predetermined time (e.g., 1 minute) or more. If water flow has not ended in S40 (NO), the process returns to S32. If water flow has ended in S40 (YES), the process returns to S22.

[0052] (Variation) In the above embodiment, a configuration has been described in which one of the multiple water heating apparatuses 1 operates as a parent unit and the rest operate as child units. Alternatively, a controller dedicated to connection control (not shown) may be connected to communication cable 140, and all of the multiple water heating apparatuses 1 may operate according to instructions from the controller dedicated to connection control. In this case, each of the multiple water heating apparatuses 1 may be able to select only the child unit operation mode as the operation mode when the connected operation mode is selected.

[0053] (Features of the Example) As described above, in one or more embodiments, linked hot water supply system 100 includes multiple hot water supply devices 1 arranged in parallel between water supply pipe 110 and hot water outlet pipe 120, and control device 30 (an example of a linked control device) of parent water supply device 1 that controls the operation of multiple hot water supply devices 1. Each of multiple hot water supply devices 1 includes burner 3 that heats water flowing into hot water supply device 1 from water supply pipe 110 as needed, flow rate adjustment valve 19 that adjusts the flow rate of water flowing into hot water supply device 1 from water supply pipe 110, flow rate sensor 18 that detects the flow rate of water flowing into hot water supply device 1 from water supply pipe 110, and control device 30 (an example of an individual control device) that can communicate with control device 30 of parent water supply device 1. Control device 30 can operate in a disconnected operation mode when it is unable to communicate with control device 30 of parent water supply device 1. In the disconnection operation mode, when the flow rate sensor 18 does not detect water flow, the control device 30 waits with the flow rate adjustment valve 19 set to a first opening degree that is smaller than fully open and larger than fully closed.

[0054] In the above-described linked hot water supply system 100, water heating apparatus 1 operating in the disconnection operation mode waits with flow rate adjustment valve 19 set to a first opening degree that is greater than fully closed, so that water continues to flow into that water heating apparatus 1 from water supply pipe 110 and that water heating apparatus 1 can be used to supply hot water. Therefore, when some water heating apparatuses 1 cannot communicate with control device 30 of the parent water heating apparatus 1, a decrease in the hot water supply capacity of linked hot water system 100 as a whole can be prevented.

[0055] In a typical linked hot water supply system 100, the water heating apparatuses 1 that operate in accordance with instructions from the control device 30 of the parent water heating apparatus 1 stand by with the flow rate adjustment valve 19 fully open or fully closed. Specifically, in the linked hot water supply system 100, among the water heating apparatuses 1 that are not yet operating, the water heating apparatus 1 that the control device 30 of the parent water heating apparatus 1 wants to operate next (for example, if none of the multiple water heating apparatuses 1 are operating, the water heating apparatus 1 that the control device 30 wants to operate first) stands by with the flow rate adjustment valve 19 fully open, and the other water heating apparatuses 1 that are not yet operating stand by with the flow rate adjustment valve 19 fully closed. This is because, when the flow rate of the entire linked hot water supply system 100 increases, water is concentrated into the water heating apparatus 1 that the control device 30 wants to operate next (for example, the water heating apparatus 1 that the control device 30 wants to operate first) to quickly start supplying hot water from that water heating apparatus 1. If water heating apparatus 1 operating in the disconnection operation mode were to wait with flow rate adjustment valve 19 fully open, then when the flow rate of the entire connected hot water supply system 100 increases, the increase in the flow rate of water flowing to water heating apparatus 1 to be operated next (for example, water heating apparatus 1 to be operated first) would be small, and hot water could not be promptly started to be supplied by that water heating apparatus 1. According to the above configuration, water heating apparatus 1 operating in the disconnection operation mode is on standby with flow rate adjustment valve 19 set to the first opening rate, which is smaller than fully open, so that when the flow rate of the entire connected hot water supply system 100 increases, the flow rate of water flowing to water heating apparatus 1 to be operated next (for example, water heating apparatus 1 to be operated first) can be significantly increased, and hot water can be promptly started to be supplied by that water heating apparatus 1.

[0056] In one or more embodiments, the controller 30 is configured to ignite the burner 3 when the flow rate detected by the flow sensor 18 is equal to or greater than a predetermined ignition flow rate. The first opening is smaller than the opening corresponding to the ignition flow rate.

[0057] According to the above configuration, the water heating device 1 operating in the disconnection operation mode waits with the flow control valve 19 set to a sufficiently small opening, so that when the flow rate of the entire connected water heating system 100 increases, the flow rate of water flowing to the water heating device 1 that is to be operated next (for example, the water heating device 1 that is to be operated first) can be increased more significantly, and hot water supply by that water heating device 1 can be started quickly.

[0058] In one or more embodiments, when the flow control valve 19 is waiting with the flow control valve 19 open to a first degree of opening and the flow sensor 18 detects water flow, the control device 30 increases the opening of the flow control valve 19 from the first degree of opening to a second degree of opening that is greater than the degree of opening corresponding to the ignition flow rate.

[0059] According to the above configuration, when the flow rate of the entire connected hot water supply system 100 increases, the flow rate of the hot water supply device 1 operating in the disconnection operation mode can be quickly increased, and hot water supply by the hot water supply device 1 operating in the disconnection operation mode can be quickly started.

[0060] In one or more embodiments, when the opening degree of the flow rate adjustment valve 19 is increased to the second opening degree and the flow rate detected by the flow rate sensor 18 increases accordingly, the control device 30 further increases the opening degree of the flow rate adjustment valve 19. When the opening degree of the flow rate adjustment valve 19 is increased to the second opening degree and the flow rate detected by the flow rate sensor 18 does not increase accordingly, the control device 30 maintains the opening degree of the flow rate adjustment valve 19 as it is.

[0061] If the flow rate that can be supplied by linked hot water supply system 100 is smaller than the flow rate that can be supplied at the hot water supply location (i.e., if linked hot water supply system 100 is a bottleneck), increasing the opening of flow adjustment valve 19 will increase the flow rate detected by flow sensor 18. Conversely, if the flow rate that can be supplied by linked hot water supply system 100 is greater than the flow rate that can be supplied at the hot water supply location (i.e., if linked hot water supply system 100 is not a bottleneck), increasing the opening of flow adjustment valve 19 will not increase the flow rate detected by flow sensor 18. With the above configuration, the opening of flow adjustment valve 19 can be increased to an opening at which linked hot water supply system 100 does not become a bottleneck.

[0062] In one or more embodiments, the control device 30 increases the opening of the flow control valve 19 when the flow rate detected by the flow sensor 18 increases while the opening of the flow control valve 19 is maintained at the second opening rate.

[0063] The flow rate detected by flow rate sensor 18 increases even though the opening degree of flow rate adjustment valve 19 is maintained when the flow rate that can be flowed by connected hot water supply system 100 is greater than the flow rate that can be flowed at the hot water supply location (i.e., connected hot water supply system 100 is not a bottleneck) and the flow rate that can be flowed at the hot water supply location increases. According to the above configuration, in such a case, the opening degree of flow rate adjustment valve 19 is increased, so the opening degree of flow rate adjustment valve 19 can be increased in accordance with the increase in the flow rate that can be flowed at the hot water supply location.

[0064] In one or more embodiments, the control device 30 reduces the opening of the flow control valve 19 when the flow rate detected by the flow sensor 18 decreases while the opening of the flow control valve 19 is maintained at the second opening rate.

[0065] The flow rate detected by flow rate sensor 18 decreases even though the opening degree of flow rate adjustment valve 19 is maintained when the flow rate that can be supplied by connected hot water supply system 100 is greater than the flow rate that can be supplied at the hot water supply location (i.e., connected hot water supply system 100 is not a bottleneck) and the flow rate that can be supplied at the hot water supply location decreases. According to the above configuration, in such a case, the opening degree of flow rate adjustment valve 19 is reduced, so the opening degree of flow rate adjustment valve 19 can be reduced in accordance with the decrease in the flow rate that can be supplied at the hot water supply location.

[0066] In one or more embodiments, each of the plurality of water heating apparatuses 1 further includes a display device 34 (an example of an alarm device). When control device 30 cannot communicate with control device 30 of parent water heating apparatus 1, it notifies via display device 34 that it is operating in a disconnection operation mode.

[0067] According to the above configuration, when communication with control device 30 of water heating apparatus 1 which is the master unit becomes impossible and the apparatus is operating in the disconnection operation mode, the user can be notified immediately.

[0068] Although the embodiments have been described in detail above, they are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone has technical utility. [Explanation of symbols]

[0069] 1: Hot water supply equipment 3: Burner 3a: First burner 3b: Second burner 3c: Third burner 4: Fan 6: Gas-liquid heat exchanger 7:Inflow pipe 8:Outflow pipe 9: Bypass pipe 10:Can body 10a: Exhaust port 11: Gas piping 12: Main gas solenoid valve 13: Gas proportional valve 14a: Gas switching solenoid valve 14b: Switching gas solenoid valve 14c: Gas switching solenoid valve 15: Igniter 16: Spark plug 17: Frame rod 18: Flow sensor 19: Flow control valve 21: Heat exchanger outlet temperature sensor 23: Outlet water temperature sensor 24: Bypass servo 25: Water supply temperature sensor 30: Control device 32: Input device 34:Display device 100: Connected hot water system 110: Water supply pipe 112: Water supply connection pipe 120: Outlet pipe 122: Outlet connecting pipe 124: Faucet 130: Gas supply pipe 132: Gas supply connecting pipe 140: Communication cable

Claims

1. A plurality of hot water supply devices are provided in parallel between the water supply pipe and the hot water outlet pipe; A linked hot water supply system including a linked control device that controls the operation of the plurality of hot water supply devices, Each of the plurality of water heaters a burner for heating water flowing into the hot water supply device from the water supply pipe as needed; a flow rate regulating valve for regulating the flow rate of water flowing from the water supply pipe into the hot water heater; a flow rate sensor for detecting the flow rate of water flowing from the water supply pipe into the hot water heater; an individual control device capable of communicating with the linkage control device; the individual control device is operable in a disconnected mode of operation when unable to communicate with the linked control device; A connected hot water supply system in which, in the disconnection operation mode, when water flow is not detected by the flow sensor, the individual control device waits with the flow control valve opening at a first opening that is smaller than fully open and larger than fully closed.

2. the individual control device is configured to ignite the burner when the flow rate detected by the flow rate sensor becomes equal to or greater than a predetermined ignition flow rate, The linked hot water system of claim 1 , wherein the first opening is smaller than the opening corresponding to the ignition flow rate.

3. The linked hot water supply system of claim 2, wherein when the flow control valve is in standby with the flow control valve at the first opening and the flow sensor detects water flow, the individual control device increases the opening of the flow control valve from the first opening to a second opening greater than the opening corresponding to the ignition flow rate.

4. the individual control device further increases the opening of the flow rate adjustment valve when the flow rate detected by the flow rate sensor increases as the opening of the flow rate adjustment valve is increased to the second opening, The linked hot water supply system of claim 3, wherein the individual control device maintains the opening of the flow control valve as it is if the flow rate detected by the flow sensor does not increase accordingly when the opening of the flow control valve is increased to the second opening.

5. 5. The linked hot water supply system of claim 4, wherein the individual control device increases the opening of the flow control valve when the flow rate detected by the flow sensor increases while the opening of the flow control valve is maintained at the second opening.

6. 5. The linked hot water supply system of claim 4, wherein the individual control device reduces the opening of the flow control valve when the flow rate detected by the flow sensor decreases while the opening of the flow control valve is maintained at the second opening.

7. Each of the plurality of water heating devices further includes an alarm device, The linked hot water supply system according to claim 1 , wherein the individual control device notifies the linking control device via the notification device that the individual control device is operating in the disconnection operation mode when the individual control device is unable to communicate with the linking control device.

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