JP7393635B2 - water heater - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a water heater, and particularly to a safety feature in an instant hot water circulation mode.

Some hot water heaters have a so-called instant hot water function that immediately supplies hot water at an appropriate temperature when the hot water tap is opened, even if the water heater has not been used for a long time. A water heater generally includes a pipe on the inflow side of hot water or a fluid such as water, a pipe on the side from which the fluid flows out, and a heating mechanism that heats the hot water or water fluid. Hereinafter, such a fluid will be referred to as "hot water."

The circulation pump related to the instant hot water function circulates hot water through the piping and heating mechanism within the water heater so as to supply hot water at an appropriate temperature immediately after the start of hot water supply (hereinafter referred to as "instant hot water circulation mode").

Regarding the safety function of instant hot water circulation, for example, Japanese Patent Laid-Open No. 2001-124357 (Patent Document 1) discloses a configuration in which a circulation pump is stopped by detecting an abnormality in a flow rate sensor provided in a circulation passage. JP-A-7-83505 (Patent Document 2) and JP-A-7-83507 (Patent Document 3) disclose a configuration in which a hot water circulation pump is stopped or started according to the output of a flow sensor.

Japanese Patent Application Publication No. 2001-124357 Japanese Patent Application Publication No. 7-83505 Japanese Patent Application Publication No. 7-83507

If the circulation pump fails to turn on (in a state in which it cannot be stopped in an operating state) during the instant hot water circulation mode, there is a possibility that the circulating hot water may be overheated. Therefore, it is desired to provide a function to detect ON failure of the circulation pump, but Patent Documents 1 to 3 do not disclose such a function.

Therefore, the present disclosure aims to provide a technique for detecting an ON failure of a circulation pump.

In an aspect of the present disclosure, a hot water supply device that dispenses hot water to a hot water tap has a heating mechanism that includes a combustion mechanism and is configured to heat a fluid passing therethrough, and a heating mechanism that has a downstream side connected to an inflow side of the heating mechanism. 1 path, a second path whose upstream side is connected to the outflow side of the heating mechanism and whose downstream side is connected to the hot water tap, a circulation pump disposed on the first path, and a discharge side of the circulation pump, A flow rate detector that detects the flow rate of the first path, a temperature detector that detects the fluid temperature of the first path on the discharge side of the circulation pump, and a controller that controls the combustion mechanism and the circulation pump, The upstream side of the circulation pump in the first path is connected to the downstream side of the second path via a third path outside the water heater, and the hot water tap is closed and the combustion mechanism and circulation pump are activated. In the instant hot water circulation mode, the third path is configured to bypass the hot water tap, and the first path allows cold fluid to flow from outside the water heater downstream of the circulation pump when the hot water tap is opened. The controller includes a means for integrating the flow rate detected by the flow rate detector, and starts integrating the flow rate detected thereafter when an off command to stop the circulation pump is output in the instant hot water circulation mode. However, when the cumulative flow rate becomes larger than the flow rate threshold value and the fluid temperature detected thereafter becomes higher than the temperature threshold value, a failure of the circulation pump is outputted.

The above disclosure provides that when other taps (e.g., a hot water tap in a sink) are opened during operation in the instant hot water circulation mode, the flow rate and fluid temperature detected at the discharge side of the circulation pump of the water heating device are Considering the influence of the flow rate and temperature of the low-temperature fluid flowing in from the outside, an ON failure of the circulation pump can be detected from the fluid or temperature. In other words, when detecting an ON failure of the circulation pump, an off command to stop the circulation pump is output, and by using the cumulative flow rate and fluid temperature detected thereafter, the cumulative flow rate and fluid temperature can be adjusted to reflect the above effects. This makes it possible to detect ON failures with high accuracy even if other faucets are used in the instant hot water circulation mode.

In another aspect of the present disclosure, there is provided a hot water supply device that dispenses hot water to a hot water faucet, the heating mechanism having a combustion mechanism and configured to heat passing fluid, and a downstream side connected to an inflow side of the heating mechanism. a first path connected to the outflow side of the heating mechanism on the upstream side and connected to the hot water tap on the downstream side, a circulation pump disposed on the first path, and a discharge of the circulation pump. a flow rate detector that detects the flow rate of the first path on the side, a temperature detector that detects the fluid temperature of the first path on the discharge side of the circulation pump, and a controller that controls the combustion mechanism and the circulation pump; The first path upstream of the circulation pump is connected to the downstream side of the second path via a third path outside the water heater, and the hot water tap is closed to connect the combustion mechanism and the circulation pump. In the instant hot water circulation mode in which the water heater is operated, the third path is configured to bypass the hot water tap, and the first path is configured to supply cold fluid from outside the water heater downstream of the circulation pump when the hot water tap is opened. The controller has means for stopping the combustion mechanism when the fluid temperature in the first path is higher than a predetermined temperature and for activating the combustion mechanism when a predetermined combustion start condition is met. However, in the instant hot water circulation mode, if an off command is output to stop the circulation pump, and after the off command is output, if the number of times the combustion mechanism is stopped exceeds a predetermined number of times, a malfunction of the circulation pump will be detected. Output.

Also in the above-mentioned disclosure, it is possible to accurately detect an ON failure of the circulation pump if another tap is used while operating in the above-mentioned instant hot water circulation mode. In other words, when detecting an ON failure of the circulation pump, an OFF command to stop the circulation pump is output, and then by using the number of times the combustion mechanism is stopped based on the fluid temperature, the fluid used to determine the stoppage is The temperature can reflect the influence of the temperature of the circulating fluid that is returned to the heating mechanism and excessively heated by the circulating pump that fails to turn ON even after the OFF command is issued. This makes it possible to detect an ON failure while reflecting the influence, and allows accurate detection of an ON failure even if other faucets are used in the instant hot water circulation mode.

According to the present disclosure, an ON failure of a circulation pump can be detected.

FIG. 1 is a diagram showing an example of a water heater 100 including a circulation port. FIG. 2 is a diagram illustrating an example of a water heater 200 that does not include a circulation port. 2 is a diagram showing an example of the configuration of a controller 250. FIG. FIG. 2 is a diagram illustrating an example of an outline of the operation of the water heater 200 in a hot water supply mode. FIG. 2 is a diagram illustrating an example of an operational outline of the hot water supply device 200 in an instant hot water circulation mode. FIG. 6 is a diagram illustrating an example of an operation outline of the hot water supply device 200 when the circulation pump 207 is turned on and fails during the hot water circulation mode. It is a figure which shows an example of the flowchart of a process. FIG. 7 is a diagram showing another example of a processing flowchart.

Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. In the following description, the entry of hot water will be referred to as "inflow", and the exit of hot water will be referred to as "outflow". Further, piping is an example of a "path" through which fluid flows.

A hot water supply device is configured to dispense hot water to a hot water faucet 140 (FIG. 1), and typically includes a port for letting tap water in and a port for letting heated hot water out. In addition, in the instant hot water circulation mode of some water heaters, in order to circulate the hot water within the hot water heater, the hot water that flows out from the port for flowing out the heated hot water flows into the hot water heater. Equipped with ports. Further, some water heaters do not have an independent circulation port, and the port for introducing tap water also serves as the circulation port.

Control of the instant hot water circulation mode according to this embodiment can be suitably applied mainly to a water heater that does not have an independent port. First, the configuration of a water heater with a port, the configuration of a water heater without a port, and the configuration of a controller that controls the water heater will be described in order. Next, a method of controlling the water heater according to the present embodiment will be described.

[Configuration of water heater]
FIG. 1 is a diagram showing an example of a water heater 100 including a circulation port. The water heater 100 includes a bypass servo 101, flow rate detectors 102 and 108, temperature detectors 103 and 105, a heat exchanger 104, a water volume servo 106, a circulation pump 107, ports 111, 112 and 113, A controller 150 is provided. In this embodiment, heat exchanger 104 includes a combustion mechanism 310 (FIG. 3) and is configured to heat the fluid passing therethrough.

Port 111 is connected to water pipe 110. Water flowing into the water heater 100 due to the water pressure from the water pipe 110 is supplied to the water heater 100 via the port 111. When the pipes in the water heater 100 are filled with water or hot water, water stops flowing from the water pipe 110 into the water heater 100. Further, when the valve 130 connected to the hot water tap 140 is open, water flowing in from the water pipe 110 flows out from the hot water tap 140. Note that the port 111 is not limited to the water pipe 110, and may be connected to a supply source that supplies low-temperature hot water (low-temperature fluid) to the water heater.

A portion of the water from port 111 passes through path 155 and into heat exchanger 104 . Further, a portion of the water that has flowed into the water heater 100 from the port 111 flows out from the port 113 via the paths 160 and 165. Path 155 is a path from the exit of bypass servo 101 to the entrance of heat exchanger 104. Further, the path 160 is a path from the exit of the bypass servo 101 to the confluence point of the path 165. Path 165 is a path from the outlet of heat exchanger 104 to port 113.

Port 112 is connected to the same piping as port 113. In the hot water circulation mode, the hot water flowing out from the port 113 flows into the water heater 100 again from the port 112 and circulates within the water heater 100 via the heat exchanger 104 .

Port 113 is connected to piping connected to hot water tap 140 . In the hot water supply mode, hot water flowing out from the port 113 is supplied to the user from the hot water faucet 140 via the valve 120. The hot water supply mode is an operation mode when hot water heated by the heat exchanger 104 flows out from the hot water tap 140 (when the user uses the hot water).

Bypass servo 101 adjusts the ratio of the amount of water flowing into path 155 and the amount of water flowing into path 160. The bypass servo 101 has, for example, a stopper driven by a stepping motor or the like, and the amount of inflow into the paths 155 and 160 can be adjusted by the stopper. Hot water flowing into the heat exchanger 104 via the path 155 is heated by the heat exchanger 104 . The water flowing into the path 160 mixes with the hot water flowing out from the heat exchanger 104 in the path 165, and adjusts the temperature of the hot water.

The flow rate detector 102 detects the amount of hot water flowing through the path 155. For example, the flow rate detector 102 includes a water wheel or the like that rotates in conjunction with the flow of hot water, and outputs a signal indicating the amount of rotation of the water wheel. Based on the signal from the flow rate detector 102, the controller 150 determines whether or not hot water is flowing through the path 155, and calculates (measures) the flow rate.

The temperature detector 103 detects the temperature of the hot water that passes through the flow rate detector 102 and flows through the path 155 using, for example, a thermistor. As shown in FIG. 1, the temperature detector 103 detects the temperature of the hot water circulating through the paths 155, 165, and 170 when the water heater 100 is operating in the instant hot water circulation mode; If it is not operating, the circulation pump 107 is not operating, so the temperature of the water flowing into the water heater 100 from the water pipe 110 can be detected. Furthermore, the temperature detector 103 can also detect the temperature of the hot water that is a mixture of the water flowing into the water heater 100 from the water pipe 110 and the hot water circulating through the paths 155, 165, and 170. Controller 150 may measure temperature based on the thermistor output signal.

In the heat exchanger 104 (heating mechanism), the hot water passing through the heat exchanger 104 is heated by the amount of combustion heat from the combustion mechanism 310, and then flows out to the path 165.

The temperature detector 105 detects the temperature of hot water flowing through the path 165 using, for example, a thermistor. Hot water passing through path 165 flows out from open hot water faucet 140 when valve 120 is open. Therefore, the temperature detector 105 can directly detect the temperature of hot water used by the user. Controller 150 can measure the temperature of the hot water flowing through path 165 based on the output signal of the thermistor.

The water amount servo 106 has a plug provided by, for example, a stepping motor, and can adjust the amount of hot water flowing out from the port 113 with the plug. Hot water flowing out from the port 113 flows out from the open hot water faucet 140 when the valve 120 is open, but when the valve 120 is closed and the hot water faucet 140 is closed, the hot water supply device 100 immediately circulates hot water. mode (ie, circulation pump 107 is activated), it flows into port 112.

Circulation pump 107 causes hot water that has flowed in from port 112 to flow out into path 170 . Hot water circulates within the water heater 100 via the heat exchanger 104 and flows into the circulation pump 107 again from the port 112. Circulation pump 107 may include a pump driven by a DC motor or the like. This DC motor may be controlled by signals from controller 150.

Similar to the flow rate detector 102, the flow rate detector 108 detects the amount of hot water flowing through the path 170 based on the amount of rotation of a water wheel or the like. The controller 150 determines whether hot water is flowing in the path 170 based on a signal indicating the amount of rotation output from the flow rate detector 108, and can calculate (measure) the flow rate.

Controller 150 controls the entire water heater 100. Specifically, the controller 150 performs data processing based on the outputs of the flow rate detectors 102 and 108, data processing based on the outputs of the temperature detectors 103 and 105, and other equipment (bypass servo 101, water volume servo 106, circulation pump 107). and heat exchanger 104, etc.), the flow rate and temperature of hot water can be adjusted. In FIG. 1, controller 150 is provided inside water heater 100, but controller 150 may be provided outside water heater 100.

Next, an outline of the operation of the hot water supply mode and the instant hot water circulation mode in the hot water supply apparatus 100 will be explained. The operation of the water heater 100 when the circulation pump 107 fails while the water heater 100 is operating in the instant hot water circulation mode will also be described.

In the hot water supply mode, the water heater 100 heats water flowing in from the water pipe 110 with the heat exchanger 104 and causes the heated hot water to flow out from the port 113. Hot water from port 113 flows out from hot water faucet 140 when valve 120 is open. The circulation pump 107 is operated in the hot water circulation mode, but is stopped in the hot water supply mode, so that the hot water flowing out from the port 113 does not flow into the path 170, or only a small amount flows into the path 170.

In the instant hot water circulation mode, the water heater 100 heats water flowing in from the water pipe 110 with the heat exchanger 104 and causes the heated hot water to flow out from the port 113. Further, the hot water flowing out from the port 113 is pushed out to the path 170 side by the circulation pump 107. The hot water flowing out from the port 113 is pushed out by the circulation pump 107 and flows into the path 170 as long as the valve 120 is closed and the hot water tap 140 is closed. When the controller 150 determines that the temperature of the hot water being circulated has reached a preset temperature, it outputs a control signal to stop the circulation pump 107. The hot water gradually stops circulating in the water heater 100 based on the fact that the circulation pump 107 has stopped.

If the circulation pump 107 has an ON failure in the instant hot water circulation mode, it cannot accept a control signal from the controller 150. When the circulation pump 107 is in the ON failure state, the circulation pump 107 does not stop even though the temperature of the hot water being circulated reaches a preset temperature, so the hot water continues to circulate and be heated. .

The controller 150 stores the operating mode status of the water heater 100 (hot water supply mode, instant hot water circulation mode, etc.) in an internal memory, and also acquires the detection result of the amount of water in the path 170 from the flow rate detector 108. Therefore, the controller 150 determines whether or not the circulation pump 107 has turned ON based on the fact that the amount of water flowing through the path 170 is greater than or equal to a predetermined threshold while the operation mode of the water heater 100 is not the immediate hot water circulation mode. It can be determined that The controller 150 can notify the user of an error that the circulation pump 107 has turned ON using an alarm or the like. As described above, the water heater 100 including the circulation port can detect an ON failure of the circulation pump 107 in the instant hot water circulation mode.

FIG. 2 is a diagram showing an example of a water heater 200 that does not include a circulation port. The water heater 200 includes a bypass servo 201, a flow rate detector 202, temperature detectors 203 and 205, a heat exchanger 204, a controller 250, a water volume servo 206, a circulation pump 207, ports 211 and 213, controller 250.

Bypass servo 201, flow rate detector 202, temperature detectors 203 and 205, heat exchanger 204, water volume servo 206, circulation pump 207, port 211, port 213, and controller 250 of water heater 200. Each of the water heater 100 includes a bypass servo 101, a flow rate detector 102, temperature detectors 103 and 105, a heat exchanger 104, a water volume servo 106, a circulation pump 107, ports 111 and 113, and a controller. 150, respectively. Further, each of routes 255, 260, and 265 corresponds to each of routes 155, 160, and 165.

Compared to the water heater 100, the water heater 200 does not include a circulation port and does not include a path corresponding to the path 170. Instead, the water heater 200 includes a circulation pump 207 upstream of the bypass servo 201. Differences in the configurations of these water heaters 100 and 200 are due to, for example, differences in the configurations of water supply facilities in different countries or regions.

As shown in FIG. 2, in a water supply system in a certain country or region, a route 280 through which water flows in from the water pipe 110 and a route 281 through which hot water flows out from the water heater 200 are connected to a route 282 outside the water heater 200. connected via. The path 280 and the path 255 are an example of a "first path," and the downstream side thereof is connected to the inflow side of the heating mechanism (heat exchanger 204), and the upstream side thereof is connected to the water pipe 110. The circulation pump 207 is arranged so as to be inserted on the "first path", and the flow rate detector 202 is configured to detect the flow rate of the "first path" on the discharge side of the circulation pump 207. Ru. Furthermore, the temperature detector 203 is configured to detect the fluid temperature of the "first path" on the discharge side of the circulation pump 207. In FIG. 2, the "first route" upstream of the circulation pump 207 is connected to a route corresponding to the "second route" via a route 282 external to the water heater 200 and corresponding to the "third route". It is connected to the downstream side of 265 and 281.

A valve 214 for preventing backflow is inserted into the path 282. Valve 214 is configured to prevent water from entering path 281 from path 280 . In the instant hot water circulation mode, when the hot water tap 140 is closed and the combustion mechanism (heat exchanger 204) and circulation pump 207 are in operation, the "third path" bypasses the hot water tap 140 in the closed state. configured.

When the hot water tap 140 in the closed state is opened, the route 280 that is the "first route" has a water supply on the downstream side of the circulation pump 207 where the water pressure is high. Water (cold fluid) is configured to flow in from the pipe 110.

In the water supply facility having this configuration, it is assumed that hot water is circulated to the hot water supply device 200 via the port 211 and the port 213. Therefore, the water heater 200 does not include a circulation port connected to a path branching from the path 281. Furthermore, since hot water needs to be circulated through the paths 281 and 260, the water heater 200 includes a circulation pump 207 downstream of the port 211.

Next, an outline of the operation of the hot water supply mode and the instant hot water circulation mode in the hot water supply apparatus 200 will be explained. Further, a problem of the hot water supply device 200 when the circulation pump 207 is turned ON in the instant hot water circulation mode will also be described.

In the hot water supply mode, the water heater 200 heats water flowing in from the water pipe 110 with the heat exchanger 204 and causes hot water to flow out from the port 213. Hot water flowing out from port 213 flows out from hot water faucet 140 when valve 120 is open. When hot water flowing through the path 281 flows out from the hot water faucet 140, no water pressure is applied to the valve 214, so no hot water flows from the path 281 to the path 280 side, or a small amount of hot water flows from the path 281 to the path 280 side. only flows in. The circulation pump 207 is stopped in hot water supply mode.

In the instant hot water circulation mode, the water heater 200 heats water flowing in from the water pipe 110 with the heat exchanger 204 and causes hot water to flow out from the port 213. The circulation pump 207 operates in the instant hot water circulation mode, and flows hot water from the port 211 in the direction of the path 255. As long as the valve 120 is closed, the force acting on the hot water flowing out from the port 213 to flow into the port 211 is exerted by the circulation pump 207. Therefore, hot water flowing out from port 213 flows into port 211 via paths 281, 282, and 280. As a result, hot water circulates through path 280, path 255, heat exchanger 204, path 265, path 281, and path 282. The route 265 and the route 281 are an example of a "second route", and the upstream side thereof is connected to the outflow side of the heating mechanism (heat exchanger 204), and the downstream side thereof is connected to the hot water tap 140 side.

When the controller 250 determines that the temperature of the hot water being circulated has reached a preset temperature, the controller 250 stops the circulation pump 207. The hot water gradually stops circulating in the water heater 200 based on the fact that the circulation pump 207 has stopped.

When the circulation pump 207 is in the ON failure state, the circulation pump 207 does not stop even though the temperature of the hot water being circulated has reached the temperature preset by the controller 250, so the hot water continues to circulate and the hot water continues to flow. heating will continue.

Although the water heater 100 was able to detect the ON failure of the circulation pump 107, the water heater 200 cannot clearly detect the ON failure of the circulation pump 207 due to the configuration of the device. The reason why the water heater 200 cannot detect the ON failure of the circulation pump 207 is that, unlike the case of the circulation pump 107 in FIG. This is because it serves as both a circulation route.

As shown in FIG. 2, the controller 250 needs to use, for example, the detection result of the flow rate detector 202 to determine whether the circulation pump 207 is out of order. If the controller 250 determines that the flow of water or hot water is not detected based on the output of the flow rate detector 202 after the instant hot water circulation mode is completed, that is, after outputting the stop signal, the controller 250 will stop the circulation pump 207 normally. It can be determined that On the other hand, even if it is determined that the flow of water or hot water is detected based on the output of the flow rate detector 202 after the completion of the instant hot water circulation mode, that is, after outputting the stop signal, the controller 250 determines that the circulation pump 207 is in an ON failure condition. It is not possible to determine whether it is present or not. This is because, even if the circulation pump 207 is turned off (stopped) normally, if the user opens the valve 120 in the hot water supply mode to let hot water flow out from the hot water faucet 140, the hot water from the water pipe 110 to the hot water supply device 200. This is because the flow rate detector 202 detects the flow of water or hot water because water flows into the chamber. In this way, in the case of the water heater 200 that does not have a circulation port, the controller 250 uses the detection results of the flow rate detector 202 to determine whether an ON failure has occurred in the circulation pump 207 or whether the user has turned on the hot water. It is not possible to clearly determine whether it is just being used.

If the water heater 200 is set at a high temperature and is circulating hot water in the instant hot water circulation mode, if the circulation pump 207 turns on and fails, the hot water will continue to circulate via the path 280 even after the instant hot water circulation mode is completed. Since the water is continuously heated, it becomes difficult to provide hot water at an appropriate temperature from the hot water tap 140 when the user opens the valve 130 in this state. In order to avoid such a situation, water heater 200 implements a control method described below.

[Controller configuration]
Referring to FIG. 3, controller 250 includes a CPU (Central Processing Unit) 301, a memory 302, an electronic circuit 303, an interface 304, and a bus 305. Controller 250 communicates with various sensors and actuators of water heater 200 to control water heater 200 . Further, the controller 250 outputs information regarding the water heater 200 through the notification device 306. Further, the controller 250 can control the water heater 200 according to the user's input to the water heater 200 that the remote controller 307 receives.

CPU 301 controls water heater 200 by executing various programs stored in memory 302. In one aspect, CPU 301 may be an embedded CPU or an FPGA (Field-Programmable Gate Array).

The memory 302 is configured to include a volatile or nonvolatile storage medium, and stores programs executed by the CPU 301 and data referenced by the CPU 301.

The electronic circuit 303 is a circuit that can execute specific processing such as data conversion or actuator control in place of the CPU 301, and can be configured with, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA.

The CPU 301 communicates with other parts of the water heater 200 via an interface 304 by wire or wirelessly. The other parts include at least a combustion mechanism 310 such as a burner of the heat exchanger 204, a circulation pump 207, temperature detectors 203 and 205, a flow rate detector 202, a bypass servo 201, and a water amount servo 206. Further, the interface 304 communicates with a notification device 306 and a remote controller 307.

The notification device 306 is configured by a speaker, a display, or a combination thereof. Notification device 306 outputs the operating state of hot water supply device 200 according to the output from CPU 301. The operating state includes, for example, an ON failure of the circulation pump 207.

[Overview of operation of water heater 200 in hot water supply mode]
The operation of water heater 200 in hot water supply mode will be described with reference to FIG. 4. The hot water supply mode is a mode when the user uses hot water flowing out from the hot water tap 140 while the circulation pump 207 is stopped. In the hot water supply mode, when the valve 120 is opened, water is supplied from the water pipe 110 to the hot water supply device 200 at any time. The water passes through the stopped circulation pump 207 and flows into the heat exchanger 204 where it is heated to a temperature set by the user and then flows out from the hot water tap 140 via the valve 120. . Arrow 400 in FIG. 4 represents the flow of hot water in the hot water supply mode.

[Outline of operation of water heater 200 in instant hot water circulation mode]
Referring to FIG. 5, in the instant hot water circulation mode, circulation pump 207 operates. In the instant hot water circulation mode, the user usually does not use the hot water tap 140 and the valve 120 is closed, so no water is supplied from the water pipe 110 to the hot water supply device 200. Therefore, hot water circulates within the water heater 200 along the flow indicated by the arrow 500 in FIG.

When CPU 301 determines that the temperature of the hot water being circulated has reached a predetermined temperature based on the output of temperature detector 203 or 205, it causes water heater 200 to complete the instant hot water circulation mode. Specifically, the CPU 301 changes the operation mode of the water heater 200 stored in the memory 302 from the instant hot water circulation mode to another mode (standby mode, etc.) and instructs the circulation pump 207 to stop. Outputs OFF command. If the circulation pump 207 is not stopped by the OFF command from the CPU 301, it enters an ON failure state (FIG. 6). When the CPU 301 detects an ON failure, the CPU 301 causes the notification device 306 to notify a message that the circulation pump 207 has experienced an ON failure. By referring to the notification contents from the notification device 306, the user can notice an abnormality in the water heater 200 and can contact a service person or the like. Details of the ON failure detection process by the CPU 301 will be described later.

[Operating procedure of water heater 200]
With reference to the flowchart of FIG. 7, the process of the instant hot water circulation mode will be described, including the process of detecting an ON failure of the circulation pump 207. The CPU 301 implements the processing by executing a predetermined program. In this process, an ON failure is determined based on the integrated value of the detected flow rate and the temperature of the incoming water. In the instant hot water circulation mode, the hot water tap 140 is normally closed and the combustion mechanism 301 and circulation pump 207 are operated.

First, the CPU 301 outputs an ON command to the circulation pump 207 (step S1). The circulation pump 207 operates according to an ON command from the CPU 301 to circulate hot water. Note that the CPU 301 may output the ON command to the electronic circuit 303, and the electronic circuit 303 may directly control the circulation pump 207 according to the ON command.

When CPU 301 detects MOQ (minimum operating flow rate) based on the output of flow rate detector 202 (step S3), it supplies fuel gas to combustion mechanism 310 to start a combustion operation (step S5). Thereby, hot water is circulated by the circulation pump 207 while being heated in the heat exchanger 204 .

When the CPU 301 determines that the temperature of the hot water being circulated has reached a predetermined temperature based on the detection results of the temperature detectors 203 and 205, it changes the state of the water heater 200 to immediate hot water circulation completion (step S7). . For example, the CPU 301 may store the status of the hot water supply device 200 (standby for hot water supply, in the middle of hot water supply, instant hot water standby, instant hot water circulation in progress, instant hot water circulation complete, etc.) in the memory 302. In that case, the CPU 301 manages the state of the water heater 200 by rewriting the state of the water heater 200 on the memory 302.

The CPU 301 outputs an OFF command to the circulation pump 207 (step S9). The circulation pump 207 stops if it can receive the OFF command from the CPU 301. When the circulation pump 207 stops, the hot water that is being circulated stops circulating after a while. Note that the CPU 301 may output an OFF command to the electronic circuit 303, and the electronic circuit 303 that has input the OFF command may stop the circulation pump 207.

After outputting the OFF command, the CPU 301 then starts measuring the cumulative flow rate (step S11). For example, in order to start integrating the flow rate based on the output of the flow rate detector 202 provided on the discharge side (downstream side) of the circulation pump 207, the CPU 301 uses [integration value] (for example, set to 0).

The CPU 301 determines whether a constant flow rate is detected based on the output of the flow rate detector 202 (step S13). If a constant flow rate is not detected (NO in step S13), it can be determined that the circulation pump 207 is stopped, and the CPU 301 ends the cumulative flow measurement (step S31), and at the same time stops supplying gas fuel to the combustion mechanism 310. The combustion operation is stopped by, for example, stopping the supply of (step S33). The process then ends.

When the CPU 301 detects a constant flow rate based on the output of the flow rate detector 202 (YES in step S13), the CPU 301 uses the detected flow rate based on the output from the flow rate detector 202 to calculate ([integrated value] = [integrated value] + detected flow rate) is performed (step S15).

The CPU 301 determines whether or not to stop combustion in the combustion mechanism 310 based on the outputs of various sensors in the water heater 200 (step S17). In this step S17, the CPU 301 determines whether or not the water inlet high cut condition or the high temperature hot water output predictive combustion prohibition condition is satisfied, and if it is determined that at least one of the conditions is satisfied (NO in step S17), the CPU 301 The combustion operation is stopped (step S35), and the process moves to step S19. This water inlet high-cut condition indicates that the inlet water temperature, that is, the temperature based on the output of the temperature detector 203 on the water inlet side, becomes higher than the first predetermined temperature. Further, the high-temperature hot water tapping predictive combustion prohibition condition indicates that the temperature based on the output of the hot water tapping side temperature detector 205 will exceed the second predetermined temperature. Note that the first predetermined temperature and the second predetermined temperature are temperatures determined through experiments, and may be the same temperature or different temperatures.

Both the water inlet high cut condition and the high temperature hot water output prediction combustion stop start condition are conditions for determining whether there is a possibility that the hot water will be excessively heated and reach a high temperature and it is necessary to stop combustion. In other words, the determination of this condition corresponds to a mechanism for stopping the circulation pump 207 when the temperature of hot water reaches the first or second predetermined temperature in the instant hot water circulation mode. If the circulation pump 207 is in an ON failure state, the circulating hot water may be excessively heated in the heat exchanger 204 and reach a high temperature. It can also be a condition for determining whether or not there is.

If the CPU 301 determines that neither the water inlet high cut condition nor the high temperature hot water output prediction combustion prohibition condition is satisfied (YES in step S17), it determines whether the condition ([integrated flow rate]>C) is satisfied (step S19). If the CPU 301 determines that the condition is not satisfied (NO in step S19), the CPU 301 determines whether the combustion mechanism 310 is in combustion (step S37).

If it is determined that gas fuel is being supplied, that is, combustion is in progress (NO in step S37), the process returns to step S13 and the flow rate is integrated. On the other hand, if it is determined that gas fuel is not being supplied, that is, combustion is not in progress (YES in step S37), the CPU 301 compares the outputs of various sensors with the combustion start conditions, and determines whether the combustion start conditions are satisfied. (Step S39). The combustion start conditions are, for example, (MOQ detection), (output water temperature > set temperature + T degrees (normal: T = 1 degree, if set temperature < 50 degrees, T = 5 degrees), (inlet water temperature < outlet temperature + 10 degrees). (degrees), (incoming water temperature < set temperature), and (can body temperature < can body set temperature + 10 degrees).Here, the outlet water temperature is the temperature based on the output of the temperature detector 205 on the hot water tap 140 side. and the can body temperature indicates the temperature of the housing of the heat exchanger 204. When the CPU 301 determines that all of the combustion start conditions are satisfied (YES in step S39), the CPU 301 causes the combustion mechanism 310 to start combustion ( In step S41), the process returns to step S13, but if it is determined that one or more of the combustion start conditions are not satisfied (NO in step S39), the process returns to step S13 without starting combustion.

In the processing of steps S17, S35, S39, and S31, the CPU 301 stops the combustion mechanism 310 when the fluid temperature of the path 280 is higher than the predetermined temperature determined in step S17, and also stops the combustion mechanism 310 as determined in step S39. A function of activating the combustion mechanism 310 is realized when a predetermined combustion start condition is satisfied.

If the CPU 301 determines that the condition ([integrated flow rate]>C) is satisfied (YES in step S19), the CPU 301 clears the value of [integrated flow rate] and ends the measurement of the integrated flow rate (step S21). The CPU 301 then determines whether a constant flow rate is detected based on the output of the flow rate detector 202 (step S23). When a constant flow rate is detected (YES in step S23), and the inlet water temperature Th is compared with the threshold value A, based on the comparison result, the condition (inlet water temperature Th>A) is not satisfied (NO in step S25), The processes of step S23 and step S25 are repeated. In the repetitive process, when the constant flow rate is no longer detected (NO in step S23), the process ends, and in the repetitive process, when the condition (inlet water temperature Th>A) is satisfied (YES in step S25). That is, when the inlet water temperature Th becomes high enough to exceed the threshold value A, the CPU 301 determines that the circulation pump 207 is in an ON failure state, outputs an error to that effect (step S27), and the hot water is heated excessively. In order to avoid this, the combustion mechanism 310 is made to stop combustion (step S29). The process then ends.

According to the process in FIG. 7, in the instant hot water circulation mode, the CPU 301 outputs an OFF command for the circulation pump 207 (step S9), and then detects a constant flow rate on the discharge side (upstream side) of the circulation pump 207 ( In the state (YES in step S23), if the inlet water temperature Th on the discharge side (upstream side) of the circulation pump 207 exceeds the threshold value A (YES in step S25), it is determined that the circulation pump 207 is in an ON failure state. This determination solves the problem of the path before and after the circulation pump 207 having the role of both a water inlet path in hot water supply mode and a circulation path in instant hot water circulation mode. That is, in the ON failure determination, whether the hot water tap 140 is operated by the user to open the hot water tap 140 and hot water is being supplied via the hot water tap 140 is taken into consideration, and an ON failure is determined.

Specifically, if a constant flow of water is flowing in (YES in step S23) and the incoming water temperature Th is not high enough to exceed the threshold A (NO in step S25), the hot water faucet 140 is operated by the user and hot water is being supplied. Therefore, it is not determined to be an ON failure, but if the condition during hot water supply does not apply, it is determined to be an ON failure.

Furthermore, regarding solving the problem, in steps S17 and S19, if the inlet water temperature does not satisfy either the inlet high-cut condition or the high-temperature outlet predicted combustion prohibition condition (YES in step S17), the user can close the hot water tap 140. Since there is a possibility that water is being supplied from the water pipe 110 due to operation, the condition ([integrated flow rate]>C) is used to determine the possibility that hot water is being supplied (step S19). .

Furthermore, regarding the above-mentioned problem, in steps S37 to S39, even if the inlet water temperature satisfies the inlet high cut condition or the high temperature outlet predicted combustion prohibition condition (NO in step S17) and combustion is stopped (step S35), the [integrated flow rate ] is below the threshold value C, there is a possibility that the hot water tap 140 is operated by the user and hot water is being supplied. Therefore, if the combustion start condition is satisfied (YES in step S39), combustion is started (step S39). S41), the temperature of the hot water from the hot water tap 140 can be maintained.

Thresholds A and C in FIG. 7 are determined experimentally. The threshold value C indicates a value that is assumed not to exceed the [integrated flow rate] even if the hot water tap 140 is operated and hot water is being supplied. The threshold value C corresponds to, for example, the capacity in the piping of the water heater 200 or the combined capacity of the capacity in the piping of the water heater 200 and the capacity in the piping of the installed circulation route. Since the length of the piping etc. differs depending on the installation location of the water heater 200, by setting the threshold value C using the capacity of the piping, the ON failure determination is performed according to the individual characteristics of the water heater 200. be able to. The threshold value C can be set manually by the operator or automatically by the controller-205.

[Other examples of operating procedures of water heater 200]
Another example of the process of detecting an ON failure of the circulation pump 207 in the instant hot water circulation mode will be described with reference to the flowchart of FIG. 8 . The CPU 301 implements the processing by executing a predetermined program. The process in FIG. 8 replaces the process related to the [integrated flow rate] in FIG. Then, an ON failure is determined (step S19a). Further, in FIG. 8, a process (step S19b) is added to reduce the time required for ON failure determination based on the number of combustion stops (step S35). The processing in the other steps in FIG. 8 is the same as the processing in the corresponding step in FIG. 7, so the description will not be repeated.

In FIG. 8, in the instant hot water circulation mode, the CPU 301 measures the time period during which the incoming water flow rate exceeds a certain flow rate on the discharge side (upstream side) of the circulation pump 207 even after the OFF command of the circulation pump 207 is output. It is determined whether the condition (timer>1h) is satisfied regarding the time measured by the timer (step S19a). If the CPU 301 determines that the condition (timer>1h) is satisfied (YES in step S19a), it determines an ON failure and issues an error notification (step S27). If the CPU 301 determines that the condition (timer>1h) is not satisfied (NO in step S19a), the process moves to step S37 and performs the same process as described above. Note that the threshold value 1h only needs to be a predetermined time, and is, for example, one hour. This is from the viewpoint that the user is unlikely to leave the hot water tap 140 open continuously even after a predetermined time (one hour) has passed after outputting the OFF command, or from the viewpoint that the combustion mechanism 310 This is based on the perspective that combustion operations lasting longer than one hour are prohibited.

In FIG. 8, in order to finally determine that there is an ON failure, a time period corresponding to a threshold value 1h is waited for, but a process for shortening this time period (step S19b) will be described. The CPU 301 counts the number n of times during the time period of the threshold value 1h that the water inlet high cut condition or the high temperature hot water outlet predicted combustion prohibition condition is satisfied (NO in step S17) and combustion is stopped (step S33), and for the number of times n ( While it is determined that the condition (n≧3) is not satisfied (NO in step S19b), time is counted; however, when it is determined that the condition (n≧3) is satisfied (YES in step S19b), the time is counted. It is determined that an ON failure has occurred, and an error is notified (step S27). As a result, an ON failure can be determined without waiting for the elapse of 1 hour when the number of times n of combustion stops due to the water inflow high cut condition or the high temperature hot water output predicted combustion prohibition condition being satisfied reaches at least 3 times. Note that the threshold value used for the condition of the number of times n is a value determined from experiments, and is not limited to three times.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

100,200 Water heater, 102,108,202,901 Flow rate detector, 103,105,203 Temperature detector, 104,204 Heat exchanger, 107,207 Circulation pump, 110 Water pipe, 111,112,113,211 , 213 port, 120, 130 valve, 140 hot water tap, 150, 250 controller, 155, 160, 165, 170, 255, 260, 265, 280, 281, 282 route, 214, 902 valve, 301 CPU, 306 notification device , 307 remote controller, 310 combustion mechanism.

Claims (4)

A hot water supply device that dispenses hot water to a hot water tap,
a heating mechanism having a combustion mechanism and configured to heat a fluid passing therethrough;
a first path whose downstream side is connected to the inflow side of the heating mechanism;
a second path whose upstream side is connected to the outflow side of the heating mechanism and whose downstream side is connected to the hot water tap;
a circulation pump disposed on the first path;
a flow rate detector that detects the flow rate of the first path on the discharge side of the circulation pump;
a temperature detector that detects the fluid temperature of the first path on the discharge side of the circulation pump;
A controller that controls the combustion mechanism and the circulation pump,
The upstream side of the circulation pump in the first path is connected to the downstream side of the second path via a third path outside the water heater,
In an instant hot water circulation mode in which the hot water tap is closed and the combustion mechanism and the circulation pump are operated, the third path is configured to bypass the hot water tap;
The first path is configured such that when the hot water tap is opened, low-temperature fluid flows into the downstream side of the circulation pump from outside the hot water supply device,
The controller includes:
comprising means for integrating the flow rate detected by the flow rate detector,
In the instant hot water circulation mode, when an off command to stop the circulation pump is output, integration of the flow rate detected thereafter is started, and the integrated flow rate becomes larger than the flow rate threshold, and the flow rate detected thereafter is started. A water heater that outputs a failure of the circulation pump when the fluid temperature becomes higher than a temperature threshold. comprising a temperature detector that detects the fluid temperature of the second path,
The controller further includes:
During the period from when the integration is started until the integrated flow rate becomes larger than the flow rate threshold, the fluid temperature in the first path becomes higher than the first predetermined temperature, or the fluid temperature in the second path becomes higher than the first predetermined temperature. 2. The water heater according to claim 1, wherein the combustion mechanism is stopped when the temperature becomes higher than a predetermined temperature. A hot water supply device that dispenses hot water to a hot water tap,
a heating mechanism having a combustion mechanism and configured to heat a fluid passing therethrough;
a first path whose downstream side is connected to the inflow side of the heating mechanism;
a second path whose upstream side is connected to the outflow side of the heating mechanism and whose downstream side is connected to the hot water tap;
a circulation pump disposed on the first path;
a flow rate detector that detects the flow rate of the first path on the discharge side of the circulation pump;
a temperature detector that detects the fluid temperature of the first path on the discharge side of the circulation pump;
A controller that controls the combustion mechanism and the circulation pump,
The upstream side of the circulation pump in the first path is connected to the downstream side of the second path via a third path outside the water heater,
In an instant hot water circulation mode in which the hot water tap is closed and the combustion mechanism and the circulation pump are operated, the third path is configured to bypass the hot water tap;
The first path is configured such that when the hot water tap is opened, low-temperature fluid flows into the downstream side of the circulation pump from outside the hot water supply device,
The controller includes:
means for stopping the combustion mechanism when the fluid temperature in the first path is higher than a predetermined temperature, and activating the combustion mechanism when a predetermined combustion start condition is satisfied;
In the instant hot water circulation mode, when an off command is output to stop the circulation pump, when the number of times the combustion mechanism is stopped exceeds a predetermined number of times after the output of the off command, the circulation pump malfunctions. A water heater that outputs a message to that effect. The controller further includes:
In the instant hot water circulation mode, when an off command is output to stop the circulation pump, when the number of times the combustion mechanism is stopped is equal to or more than a predetermined number during a predetermined period of time after outputting the off command, the circulation pump is stopped. The water heater according to claim 3, which outputs a message indicating that the pump is out of order.

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