Hot water storage type water heater

Abstract

To provide a small-sized hot water storage type water heater which can tap hot water of a stable hot water temperature with a simple structure.SOLUTION: A hot water storage type water heater includes: a can body 1a; a burner 3; can body temperature detection means 12; a hot water tapping pipe 10; a water supply port 9a communicated with the lower part of the can body 1a; a water supply pipe 9; a hot water outlet 21 provided at the upper part of the can body 1a; a hot water return port 22 communicated with the lower part of the can body 1a; a circulation passage 23 including a circulation pump 24 for circulating the hot water from the hot water outlet 21 to the hot water return port 22; water supply determination means for determining whether water is supplied to the can body 1a from the water supply pipe 9; and a control part 16 including heating control means of the burner 3. The hot water return port 22 is disposed so as to raise the temperature of the water supplied to the can body 1a from the water supply port 9a by the hot water discharged from the hot water return port 22. The control part 16 starts driving the circulation pump 24 when the water supply determination means has determined that water is supplied to the can body 1a, and stops driving the circulation pump 24 when it is determined that the water is not supplied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hot water storage type water heater that always stores a predetermined amount of warm water in a can body and supplies hot water at a set temperature to a hot water supply location. More specifically, it relates to a small-sized hot water storage type water heater with a reduced can body volume.

Background Art

[0002] In the conventional type of this kind, there are provided a can body that connects a water supply pipe and a hot water supply pipe to store hot and cold water, a burner that heats the hot and cold water in the can body, and can body temperature detection means such as a can body thermistor that detects the temperature of the hot and cold water in the can body. When the temperature of the hot and cold water detected by the can body temperature detection means is maintained at the set temperature, if it becomes lower than the combustion on temperature set based on the set temperature, the burner unit starts combustion, and if it becomes higher than the combustion off temperature, the combustion of the burner unit stops. There is a device that performs on / off control of the burner. (For example, Patent Document 1)

[0003] In this conventional device, when a hot water supply faucet at a predetermined location of the hot water outlet pipe is opened from a state where hot water supply is not in use and hot water is discharged, as a result, low-temperature water is supplied from the water supply pipe into the can body, and as a result, the temperature of the hot and cold water in the can body decreases. When the temperature detected by the can body temperature detection means reaches the combustion on temperature, or when the temperature in the can body decreases due to natural heat dissipation without discharging hot water and the temperature detected by the can body temperature detection means reaches the combustion on temperature, the combustion of the burner is started.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the case of a small-sized hot water storage type water heater with a reduced can volume, although there are advantages such as good workability during installation due to the small mass of the device and easy securing of the installation space, in actual use, when the hot water tap is opened and hot water supply is performed, the high-temperature hot water in the can is discharged, and at the same time, cold water flows in from the water supply pipe. When the combustion on temperature is reached, the combustion of the burner part starts, and the cold inflowing water and the hot water heated by combustion stay in the can, resulting in the problem that the temperature in the can does not become uniform and the hot water discharge temperature from the hot water discharge pipe is not stable.

[0006] The present invention has been made in view of such a background, and an object thereof is to provide a small-sized hot water storage type water heater that can discharge hot water with a stable hot water temperature with a simple configuration.

Means for Solving the Problem

[0007] The present invention has been made to achieve the above object. In claim 1, there are a can body, a burner that on-off burns fuel oil at the lower part of the can body, can body temperature detection means for detecting the temperature of the can body, a hot water discharge port provided at the upper part of the can body, a hot water discharge pipe connected to the hot water discharge port and provided with a hot water tap, a water supply port communicating with the lower part of the can body, a water supply pipe connected to the water supply port, a hot water outlet provided at the upper part of the can body, a hot water return port communicating with the lower part of the can body, a circulation path for communicating the hot water outlet and the hot water return port, a circulation pump provided in the circulation path for circulating the hot water and water in the can body from the hot water outlet to the hot water return port, water supply determination means for determining whether water is supplied from the water supply pipe to the can body, and heating control means for turning on the burner when the value detected by the can body temperature detection means is lower than a first temperature and turning off the burner when the value detected by the can body temperature detection means exceeds a second temperature higher than the first temperature. The control unit is provided. The hot water return port is arranged so that the temperature of the water supplied from the water supply port to the can body can be raised by the hot water discharged from the hot water return port. The control unit starts driving the circulation pump when the water supply determination means determines that water is being supplied to the can body, and stops driving the circulation pump when the water supply determination means determines that water is not being supplied to the can body.

[0008] In claim 2, a feed water temperature control chamber communicating with the lower part of the can body through a communication passage, and the water inlet and the hot water return port are provided in the feed water temperature control chamber.

[0009] In claim 3, the water inlet is provided at the lower part of the can body, and the hot water return port is provided near the water inlet at the lower part of the can body.

[0010] In claim 4, the water supply determination means includes a flow rate detection means for detecting the presence or absence of a flow in the water supply pipe or the hot water discharge pipe. When the value detected by the flow rate detection means is equal to or greater than a first flow rate, it is determined that water is being supplied to the can body. When the value detected by the flow rate detection means is less than the first flow rate, it is determined that water is not being supplied to the can body.

[0011] In claim 5, the water supply determination means includes a first timer for measuring the time from when the burner is turned off to when it is turned on. When the time of the first timer is less than a first time, it is determined that water is being supplied to the can body. When the time of the first timer is equal to or greater than the first time, it is determined that water is not being supplied to the can body.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a small-sized hot water storage type water heater that can discharge hot water with a stable hot water temperature with a simple configuration.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0014] The first embodiment according to the present invention will be described with reference to FIGS. 1 to 4.

[0015] 1 is a small storage type water heater, 1a is a cylindrical can body for storing a certain amount of hot water and cold water inside, 2 is a combustion chamber formed inside the lower part of the can body 1a, 3 is a gun type burner in which an ignition electrode 4 and a nozzle 5 are integrated and face the combustion chamber 2, and the hot water and cold water in the can body 1a are heated by the combustion of the burner 3.

[0016] 6 is an exhaust chamber adjacent to the upper part of the can body 1a, 7 is a plurality of smoke pipes communicating the combustion chamber 2 and the exhaust chamber 6, 8 is an exhaust pipe connected to the exhaust chamber 6, and the combustion gas generated in the combustion chamber 2 by the combustion of the burner 3 is sent from the combustion chamber 2 through the smoke pipe 7 to the exhaust chamber 6 and exhausted from the exhaust pipe 8.

[0017] 30 is a hot water temperature control chamber communicated with the lower part of the can body 1a through a communication passage 31.

[0018] 9a is a water inlet provided in the hot water temperature control chamber 30, and 9 is a water supply pipe connected to the water inlet 9a and supplying water from the city water supply to the hot water temperature control chamber 30 and the inside of the can body 1a.

[0019] The hot water storage type water heater 1 is provided with water supply determination means for determining whether water is supplied from the water supply pipe 9 to the can body 1a, and is provided with flow rate detection means 19 as detection means for this water supply determination means. The flow rate detection means 19 is provided in the water supply pipe 9 and detects the presence or absence of the flow of water in the water supply pipe 9. The determination criteria of the water supply determination means will be described later.

[0020] 10a is a hot water outlet connected to the upper part of the can body 1a, 10 is a hot water outlet pipe connected to the hot water outlet and supplying the hot water stored in the can body 1a to a hot water faucet 11 installed at a predetermined location such as a washroom, and 12 is a hot water storage temperature sensor as can body temperature detection means for detecting the temperature of the hot water in the can body 1a.

[0021] 21 is a hot water outlet provided at the upper part of the can body 1a, 22 is a hot water return port provided in the hot water temperature control chamber 30, 23 is a circulation path connecting the hot water outlet 21 and the hot water return port 22, and 24 is a circulation pump provided in the circulation path 23 for circulating the high-temperature hot water at the upper part of the can body 1a from the hot water outlet 21 to the hot water return port 22 via the circulation path 23. The hot water return port 22 is provided in the hot water temperature control chamber 30 so that the temperature of the water supplied from the water supply port 9a to the can body 1a is raised by the hot water discharged from the hot water return port 22.

[0022] 13 is a remote controller for giving an operation instruction to the hot water storage type water heater 1. The remote controller 13 is provided with a temperature setting switch 14 for setting the hot water supply set temperature and various switches (not shown), and is provided with a display unit 15 for displaying the state of the hot water storage type water heater 1, the hot water supply set temperature, etc.

[0023] 16 is a control unit having a microcomputer that is communicably connected to the remote controller 13 and receives the detected temperature of the can body temperature detection means 12, signals from the remote controller 13, and signals from the flow rate detection means 19, and controls the driving of the burner 3, the circulation pump 24, and each actuator.

[0024] 50 is a housing of the hot water storage type water heater 1 that houses the can body 1a and the circulation path 23 inside.

[0025] The control unit 16 controls the combustion to be turned on and off so as to keep the temperature of the hot water in the can body 1a at a predetermined temperature set by the user. Specifically, when the detected temperature of the can body temperature detection means 12 falls below a first temperature T1 (combustion on temperature) (for example, 38°C) lower than the set temperature (for example, 42°C), the combustion of the burner 3 with a fixed combustion capacity is turned on. When the detected temperature of the can body temperature detection means 12 exceeds a second temperature T2 (combustion off temperature) which is the same as the set temperature, the control is performed to turn off the combustion of the burner 3, and it is provided with a heating control means for maintaining the temperature of the hot water in the can body 1a at the set temperature. The hot water maintained at the set temperature is used for hot water supply.

[0026] The determination criteria of the water supply determination means described above are as follows: when the value detected by the flow rate detection means 19 is equal to or greater than the first flow rate F1, it is determined that water is being supplied to the can body 1a, and when the value detected by the flow rate detection means 19 is less than the first flow rate F1, it is determined that water is not being supplied to the can body 1a. In response to this, when the water supply determination means determines that water is being supplied to the can body 1a, the control unit 16 starts driving the circulation pump 24, and when the water supply determination means determines that water is not being supplied to the can body 1a, the control unit 16 stops driving the circulation pump 24.

[0027] Details will be described based on FIGS. 3 and 4. If the detected temperature of the can body temperature detection means 12 is less than the first temperature T1 in step S1, the control unit 16 turns on the burner 3 (step S2). If the detected temperature of the can body temperature detection means 12 is equal to or greater than the first temperature T1, it is determined whether it is equal to or greater than the second temperature T2. If it is equal to or greater than the second temperature T2 (YES in step S3), the burner 3 is turned off (step S4). Furthermore, when the detected value of the flow rate detection means 19 is equal to or greater than the first flow rate F1 (YES in step S5), the control unit 16 determines that water has been supplied to the can body 1a (step S6) and starts driving the circulation pump 24 (step S7). On the other hand, when the detected value of the flow rate detection means 19 is less than the first flow rate F1 (NO in step S5), the control unit 16 determines that there is no water supply to the can body 1a (step S8) and stops driving the circulation pump 24 (step S9).

[0028] The operation of the first embodiment will be described.

[0029] Based on the detected temperature of the can body temperature detection means 12, when the detected temperature of the can body temperature detection means 12 is lower than the first temperature T1, the control unit 16 turns on the burner 3, and when the detected temperature of the can body temperature detection means 12 is higher than the second temperature T2, the control unit 16 turns off the burner 3. In this way, the temperature of the hot water in the can body 1a can be maintained at the second temperature T2 which is the set temperature, and when the next hot water faucet 11 is opened, hot water with a hot water temperature of the second temperature T2 can be supplied. When the user opens the hot water faucet 11, hot water flows out from the hot water faucet 11, and at the same time, cold city water flows into the can body 1a of the small storage type water heater 1 from the water supply pipe 9 through the water temperature control chamber 30. When the detected temperature of the can body temperature detection means 12 becomes lower than the first temperature T1 due to the inflow of cold city water, the burner 3 is turned on.

[0030] In the present invention, a water supply determination means for determining whether water is supplied from the water supply pipe 9 to the can body 1a is provided, and the hot water return port 22 is arranged so that the temperature of the water supplied from the water supply port 9a to the can body 1a can be raised by the hot water discharged from the hot water return port 22. Specifically, a water temperature control chamber 30 is provided, the water supply port 9a and the hot water return port 22 are provided in the water temperature control chamber 30, and when the water supply determination means determines that water is being supplied to the can body 1a, the circulation pump 24 is started to be driven. Therefore, when the hot water faucet 11 is opened and the detected value of the flow rate detection means 19 becomes equal to or greater than the first flow rate F1, the water supply determination means determines that water has been supplied to the can body 1a, and the circulation pump 24 is started to be driven. When the driving of the circulation pump 24 is started, the high-temperature hot water at the upper part of the can body 1a flows from the hot water outlet 21 to the hot water return port 22, is poured into the water temperature control chamber 30, and mixes with the cold city water flowing into the water temperature control chamber 30 from the water supply port 9a in the water temperature control chamber 30. As a result, the temperature of the city water poured into the can body 1a can be raised. Therefore, the circulation pump 24 circulates the high-temperature hot water of the can body 1a from the hot water outlet 21 provided at the upper part of the can body 1a to the hot water return port 22 communicating with the lower part of the can body 1a.

[0031] When the user closes the hot water faucet 11, the inflow of city water from the water supply pipe 9 stops, the detected value of the flow rate detecting means 19 becomes less than the first flow rate F1, the water supply determining means determines that there is no water supply to the can body 1a, and the driving of the circulation pump 24 is stopped.

[0032] As a result, while the hot water faucet 11 is open, the temperature of the water from the water supply pipe 9, which would otherwise rapidly lower the temperature of the hot water in the can body 1a, can be raised, and the water in the can body 1a can be heated by the burner 3. Further, the hot water in the can body 1a can be circulated through the circulation path 23 to equalize the water temperature in the can body 1a. Therefore, it is possible to provide hot water with a stable hot water temperature from the hot water faucet 11. Also, regarding the circulation pump 24, when the detected value of the flow rate detecting means 19 becomes equal to or greater than the first flow rate F1 and there is water supply to the can body 1a, the driving of the circulation pump 24 is started, and when the detected value of the flow rate detecting means 19 becomes less than the first flow rate F1 and there is no water supply to the can body 1a, the driving of the circulation pump 24 is stopped. Therefore, the circulation pump 24 is driven only when the hot water faucet 11 is open and hot water is being discharged, without consuming unnecessary power of the circulation pump 24, which is efficient.

[0033] Note that the flow rate detecting means 19 may be provided in the hot water discharge pipe 10 to detect the presence or absence of the flow of hot water in the hot water discharge pipe 10.

[0034] Next, a second embodiment will be described with reference to FIG. 5. The second embodiment is a modification of the first embodiment, in which the hot water temperature control chamber 30 of the configuration of the first embodiment is connected to the can body 1a, and the communication passage 31 is an opening formed in a partition wall 31a that separates the hot water temperature control chamber 30 and the can body 1a. Other configurations are the same as those of the first embodiment, and the same special effects as those of the first embodiment are achieved.

[0035] Next, a third embodiment will be described with reference to FIG. 6. The third embodiment is a modification of the second embodiment, in which the feed water temperature control chamber 30 having the configuration of the second embodiment is formed inside the can body 1a, and the communication passage 31 is an opening formed in a partition wall 31a that separates the feed water temperature control chamber 30 and the inside of the can body 1a. Other configurations are the same as those of the first embodiment, and exhibit the same special effects as the first embodiment.

[0036] Next, the fourth embodiment will be described with reference to FIG. 7.

[0037] In the fourth embodiment, the water supply determination means in the configuration of the first embodiment is different. That is, as shown in FIG. 8, the storage type water heater 104 of the fourth embodiment includes a first timer 20 that measures the time from when the burner 3 is turned off to when it is turned on within the control unit 16. The determination criterion of the water supply determination means in the fourth embodiment is that when the time measured by the first timer 20 is less than the first time TM1 (for example, 30 seconds), it is determined that water is being supplied to the can body 1a, and when the time measured by the first timer 20 is greater than or equal to the first time TM1, it is determined that water is not being supplied to the can body 1a. In response to this, when the water supply determination means determines that water is being supplied to the can body 1a, the control unit 16 starts driving the circulation pump 24, and when the water supply determination means determines that water is not being supplied to the can body 1a, the control unit 16 stops driving the circulation pump 24.

[0038] Details will be described based on FIGS. 3 and 9. As described with reference to FIG. 3, if the detected temperature of the can body temperature detection means 12 is less than the first temperature T1 in step S1, the control unit 16 turns on the burner 3 (step S2), and if the detected temperature of the can body temperature detection means 12 is greater than or equal to the first temperature T1, it determines whether it is greater than or equal to the second temperature T2. If it is greater than or equal to the second temperature T2 (YES in step S3), the burner 3 is turned off (step S4). Furthermore, as shown in FIG. 9, when the burner 3 is turned on (step S10) and then turned off (step S11), the control unit 16 resets and starts the first timer 20 (step S12). After that, it is checked whether the burner 3 is turned on again in step S13. If it is turned on, it is determined that the detected temperature of the can body temperature detection means 12 is lower than the first temperature T1 and water is supplied to the can body 1a (step S14), and the circulation pump 24 is turned on (step S15). If the burner 3 remains off in step S13 and the first timer 20 measures the first time TM1 or more in step S16, since the burner 3 has not been turned on until the first time TM1 has elapsed, it is determined that no water is supplied to the can body 1a (step S17), and the circulation pump 24 is turned off (step S18).

[0039] The operation of the fourth embodiment will be described.

[0040] The on / off combustion of the burner 3 by the control unit 16 is the same as that of the first embodiment. In the present invention, water supply determination means for determining whether water is supplied from the water supply pipe 9 to the can body 1a is provided. The hot water return port 22 is arranged so that the temperature of the water supplied from the water supply port 9a to the can body 1a can be raised by the hot water discharged from the hot water return port 22. Specifically, a water supply temperature control chamber 30 is provided, and the water supply port 9a and the hot water return port 22 are provided in the water supply temperature control chamber 30. When the water supply determination means determines that water is supplied to the can body 1a, the circulation pump 24 is started to be driven. Therefore, when the hot water faucet 11 is opened and water is supplied from the water supply pipe 9 to the can body 1a, and the detected temperature of the can body temperature detection means 12 is lower than the first temperature T1, the burner 3 is turned on. After that, when the detected temperature of the can body temperature detection means 12 becomes the second temperature T2 or more and the burner 3 is turned off, the first timer 20 is reset and counting is started (step S12). If the burner 3 is turned on before the first time TM1 has elapsed, since the hot water faucet 11 is opened and hot water is discharged, it is determined that water is supplied from the water supply pipe 9 to the can body 1a, and the circulation pump 24 is started to be driven. When the driving of the circulation pump 24 is started, the high-temperature hot water at the upper part of the can body 1a flows from the hot water outlet 21 to the hot water return port 22 and is poured into the water supply temperature control chamber 30. In the water supply temperature control chamber 30, it mixes with the water flowing into the water supply temperature control chamber 30 from the water supply port 9a. As a result, the temperature of the water poured into the can body 1a can be raised.

[0041] Thereafter, when the detected temperature of the can body temperature detection means 12 becomes equal to or higher than the second temperature T2 and the burner 3 is turned off, the first timer 20 is reset and counting starts (step S12). If the burner 3 does not turn on until the first time TM1 elapses, it is determined that there is no water supply to the can body 1a, and the driving of the circulation pump 24 is stopped.

[0042] Thereby, the circulation pump 24 is driven at an appropriate timing, the temperature of the water in the water supply pipe 9 that rapidly decreases the temperature of the hot and cold water in the can body 1a is increased, and the can body 1a can be heated by the burner 3. Further, by circulating the hot and cold water in the can body 1a through the circulation path 23, the water temperature in the can body 1a can be made uniform. Therefore, hot and cold water with a stable hot water temperature can be provided from the hot water tap 11. Also, regarding the circulation pump 24, since the driving of the circulation pump 24 is started when the time from when the burner 3 is turned off until it is turned on is less than the first time TM1, it is possible to appropriately detect the case where there is a large amount of water supply in a short time and start driving the circulation pump 24, which is efficient. Also, when the time from when the burner 3 is turned off until it is turned on is equal to or longer than the first time TM1, that is, when the burner 3 does not turn on until the first time TM1 elapses after the burner 3 is turned off, the driving of the circulation pump 24 is stopped. Therefore, when the hot water temperature in the can body 1a slowly decreases due to natural heat dissipation or the like, the circulation pump 24 can be stopped, and the circulation pump 24 is not continuously driven unnecessarily, and the power of the circulation pump 24 is not consumed unnecessarily, which is efficient.

[0043] Next, a fifth embodiment will be described with reference to FIG. 10.

[0044] The fifth embodiment is a modification of the first embodiment. The hot water temperature control chamber 30 having the configuration of the first embodiment is abolished, the water supply port 9a is disposed at the lower part of the can body 1a, and the hot water return port 22 is provided in the vicinity of the water supply port 9a close to the water supply port 9a at the lower part of the can body 1a. Other configurations are the same as those in the first embodiment. When the hot water faucet 11 is opened and the detected value of the flow rate detection means 19 becomes equal to or greater than the first flow rate F1, the water supply determination means determines that water has been supplied to the can body 1a and starts driving the circulation pump 24. When the driving of the circulation pump 24 is started, the high-temperature hot water at the upper part of the can body 1a flows from the hot water outlet 21 to the hot water return port 22 and is poured into the lower part of the can body 1a. On the other hand, the water flowing into the can body 1a from one water supply port 9a mixes with the water in the lower part of the can body 1a. As a result, the temperature of the water poured into the can body 1a can be raised.

[0045] When the user closes the hot water faucet 11, the inflow of water from the water supply pipe 9 stops, the detected value of the flow rate detection means 19 becomes less than the first flow rate F1, the water supply determination means determines that no water is supplied to the can body 1a, and the driving of the circulation pump 24 is stopped.

[0046] As a result, while the hot water faucet 11 is open, the temperature of the water from the water supply pipe 9, which would otherwise cause the temperature of the hot water in the can body 1a to drop rapidly, can be raised and heated by the burner 3 in the can body 1a. Further, the hot water in the can body 1a can be circulated through the circulation path 23 to make the water temperature in the can body 1a uniform. Therefore, hot water with a stable hot water temperature can be provided from the hot water faucet 11. Also, for the circulation pump 24, when the detected value of the flow rate detection means 19 becomes equal to or greater than the first flow rate F1 and water is supplied to the can body 1a, the driving of the circulation pump 24 is started. When the detected value of the flow rate detection means 19 becomes less than the first flow rate F1 and water supply to the can body 1a stops, the driving of the circulation pump 24 is stopped. Therefore, the circulation pump 24 is driven only when the hot water faucet 11 is open and hot water is being discharged, without consuming unnecessary power of the circulation pump 24, which is efficient.

[0047] Next, a sixth embodiment will be described with reference to FIG. 11.

[0048] The sixth embodiment is a modification of the fourth embodiment. The feed water temperature control chamber 30 in the configuration of the fourth embodiment is abolished, the water inlet 9a is disposed at the lower part of the can body 1a, and the hot water return port 22 is provided in the vicinity of the water inlet 9a close to the water inlet 9a at the lower part of the can body 1a. Other configurations are the same as those of the fourth embodiment. When the water supply determination means determines that water is being supplied to the can body 1a, the circulation pump 24 is started to be driven. Therefore, when the hot water faucet 11 is opened and water is supplied from the water supply pipe 9 to the can body 1a, when the detected temperature of the can body temperature detection means 12 falls below the first temperature T1, the burner 3 is turned on. After that, when the detected temperature of the can body temperature detection means 12 becomes equal to or higher than the second temperature T2 and the burner 3 is turned off, the first timer 20 is reset and counting is started. If the burner 3 is turned on before the first time TM1 elapses, since the hot water faucet 11 is opened and hot water is being discharged, it is determined that water is being supplied from the water supply pipe 9 to the can body 1a, and the circulation pump 24 is started to be driven. When the driving of the circulation pump 24 is started, the high-temperature hot water at the upper part of the can body 1a flows from the hot water outlet 21 to the hot water return port 22 and is poured into the lower part of the can body 1a, and mixes with the water flowing into the can body 1a from one water inlet 9a at the lower part inside the can body 1a. As a result, the temperature of the water poured into the can body 1a can be raised.

[0049] After that, when the detected temperature of the can body temperature detection means 12 becomes equal to or higher than the second temperature T2 and the burner 3 is turned off, the first timer 20 is reset and counting is started. If the burner 3 is not turned on before the first time TM1 elapses, it is determined that there is no water supply to the can body 1a, and the driving of the circulation pump 24 is stopped.

[0050] Thereby, the circulation pump 24 is driven at an appropriate timing to raise the temperature of the water from the water supply pipe 9 that would otherwise cause the temperature of the hot water in the can body 1a to drop rapidly, and the water can be heated by the burner 3 inside the can body 1a. Furthermore, by circulating the hot water in the can body 1a through the circulation path 23, the water temperature inside the can body 1a can be made uniform, so that hot water with a stable hot water temperature can be provided from the hot water faucet 11. Also, regarding the circulation pump 24, since the circulation pump 24 is started when the time from when the burner 3 is turned off until it is turned on is less than the first hour TM1, it is possible to appropriately detect the case where there is a large amount of water supply in a short time and start driving the circulation pump 24, which is efficient. Also, when the time from when the burner 3 is turned off until it is turned on is equal to or more than the first hour TM1, that is, when the burner 3 has not been turned on until the first hour TM1 has elapsed after the burner 3 is turned off, the circulation pump 24 is stopped. Therefore, when the hot water temperature in the can body 1a slowly decreases due to natural heat dissipation or the like, the circulation pump 24 can be stopped, and the circulation pump 24 is not continuously driven unnecessarily, and the power of the circulation pump 24 is not consumed unnecessarily, which is efficient.

[0051] In addition, the other configurations used in this embodiment are presented as examples and are not intended to limit the scope of the invention. It can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0052] 1, 102, 103, 104, 105, 106: Storage type water heater 1a: Can body 3: Burner 9: Water supply pipe 9a: Water inlet 10: Hot water outlet pipe 11: Water faucet 12: Can body temperature detection means 16: Control unit 19: Flow rate detection means 20: First timer 21: Hot water outlet 22: Hot water return port 23: Circulation path 24: Circulation pump 30: Water temperature adjustment chamber 31: Communication path F1: First flow rate T1: First temperature T2: Second temperature TM1: First time

Claims

1. A can body, a burner that turns fuel on and off for combustion at the lower part of the can body, a can body temperature detection means for detecting the temperature of the can body, a hot water outlet provided at the upper part of the can body, a hot water pipe connected to the hot water outlet and provided with a faucet, a water inlet communicating with the lower part of the can body, a water supply pipe connected to the water inlet, a warm water outlet provided at the upper part of the can body, a warm water return port communicating with the lower part of the can body, a circulation path that connects the warm water outlet and the warm water return port, a circulation pump provided in the circulation path for circulating the hot and cold water in the can body from the warm water outlet to the warm water return port, a water supply determination means for determining whether water has been supplied from the water supply pipe to the can body, a control unit provided with heating control means for turning on the burner when the value detected by the can body temperature detection means is lower than a first temperature, and turning off the burner when the value detected by the can body temperature detection means exceeds a second temperature higher than the first temperature, comprising the warm water return port is arranged so that the temperature of the water supplied from the water inlet to the can body can be raised by the warm water discharged from the warm water return port, the control unit starts driving the circulation pump when the water supply determination means determines that water is being supplied to the can body, and stops driving the circulation pump when the water supply determination means determines that water is not being supplied to the can body A storage type water heater characterized by the above.

2. a water temperature adjustment chamber communicating with the lower part of the can body through a communication path, the water inlet and the warm water return port are provided in the water temperature adjustment chamber The storage type water heater according to claim 1, characterized by the above.

3. the water inlet is provided at the lower part of the can body, the warm water return port is provided near the water inlet at the lower part of the can body The storage type water heater according to claim 1, characterized by the above.

4. the water supply determination means comprises a flow rate detection means for detecting the presence or absence of a flow in the water supply pipe or the hot water pipe, when the value detected by the flow rate detection means is equal to or greater than a first flow rate, it is determined that water is being supplied to the can body, when the value detected by the flow rate detection means is less than the first flow rate, it is determined that water is not being supplied to the can body The storage type water heater according to any one of claims 2 or 3, characterized by the above.

5. the water supply determination means comprises a first timer for measuring the time from when the burner is turned off to when it is turned on, when the time of the first timer is less than a first time, it is determined that water is being supplied to the can body, When the time of the first timer is equal to or longer than the first time, it is determined that water is not supplied to the can body. The hot water storage type water heater according to any one of claims 2 or 3, characterized in that.

Images