JP2011043274A - Water heater including hot water piping for hot water filling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater capable of reducing the level of operating sound (noise) during hot water filling operation having a relatively long operation duration. <P>SOLUTION: The water heater 1 at least includes: a combustion part 10 constituted by juxtaposing two or more burners 11, 12, 13; a heat exchanger 20; and a combustion control means 30 for performing combustion control of each burner at combustion amount between lower limit combustion amount and upper limit combustion amount. The combustion control means 30 includes a hot water filling mode selection switch for guiding a flow of hot water to hot water piping 48 for hot water filling when turned on. The combustion control means further includes a silent set switch and, when the hot water filling mode selection switch is ON and the silent set switch is ON, executes silent hot water filling mode for performing combustion control of all of the burners in a predetermined range from the lower limit combustion amount of each burner to intermediate combustion amount or combustion control to fix the combustion amount of all of the burners at the lower limit combustion amount of the respective burners. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water heater provided with a hot water hot water pipe, and more particularly to a water heater capable of suppressing the volume generated from the water heater during hot water operation.

  It has a combustion section composed of a burner that uses city gas as fuel and a heat exchanger, and heat is exchanged between the combustion gas from the burner and the water supplied to it in the heat exchanger. A hot water heater in which the hot water is supplied to the outside through a hot water pipe is known. The water heater includes combustion control means, and the combustion control means controls the burner combustion between the lower limit combustion amount and the upper limit combustion amount of the burner so as to correspond to the required hot water temperature and amount of hot water. Execute. In addition, the hot water heater has a form including a general hot water supply hot water pipe for supplying hot water to a hot water tap such as a faucet and a hot water hot water pipe for supplying hot water to a bathtub, in which case combustion control means Is provided with a hot water beam mode selection switch, and when the hot water beam mode selection switch is turned ON, the hot water flowing through the hot water pipe is guided to the hot water pipe for hot water, and is guided into the bathtub from there.

  In general, the burner constituting the combustion section is composed of two or more burners that are independently controlled for combustion, and first the first burner according to the required hot water supply output (combustion amount). Only the combustion control is performed between the lower limit combustion amount and the upper limit combustion amount. When the combustion amount of only the first burner cannot answer the required hot water supply output, the combustion control means further performs the combustion of the second and third burners so that the required combustion amount can be obtained. To. Even then, the combustion amount of each burner to be burned, as is corresponding to the load that is being sought, also varies between a lower limit combustion amount and the upper limit combustion amount.

  The water heater is provided with a combustion air supply fan, and the combustion control means controls the rotation speed of the combustion air supply fan so that air necessary for combustion is supplied. If many air quantity sought, the rotation speed of the combustion air supply fan is increased, accordingly, the volume caused by the combustion air supply fan is also increased. Also, in the case of a water heater, due to its structure, when there are multiple burners, air is supplied equally from the combustion air supply fan to all burners, regardless of whether they are burning or not. It has become so.

  In the burner, the flame length changes according to the amount of combustion. As the flame length increases, the combustion noise associated with combustion increases. It flame length is long is that more of the combustion gas is supplied to the burner, accordingly, also increases the supply amount of the air required for combustion. As a result, the volume generated due to the combustion air supply fan also increases. Thus, in the water heater, when the combustion amount (hot water supply output) increases, the operation sound generated by the water heater also increases.

  FIG. 10 shows an example of the sound volume generated by a water heater having three burners a, b, and c, with the hot water supply output on the horizontal axis and the operating sound on the vertical axis. In 1 combustion control region I, hot water supply output from G1a to G1b is obtained by combustion of only the first burner a, and at the upper limit combustion amount G1b of the first burner a, the combustion air supply fan has the maximum rotational speed. As a result, the maximum K1 (dB) driving sound is generated.

  In the second combustion control region II, which is the combustion amount of G2a to G2b, the second burner b participates in the combustion in addition to the first burner a, and here, it is necessary for the combustion from the two burners. Since the hot water supply output is provided, the flame lengths of the first burner a and the second burner b are temporarily reduced. Therefore, the amount of air supplied from the combustion air supply fan can be reduced, and the rotation speed of the combustion air supply fan is reduced. As a result, the operation sound is also reduced to K2 (dB) (<K1 (dB)). . However, at the upper limit combustion amount G2b of the second combustion control region II, the rotational speed of the combustion air supply fan is maximized again, and as a result, K1 (dB) or an operating noise (noise) exceeding it is generated. This means that the first burner a, the second burner a, the second combustion control region III, which is a hot water supply output of G3a to G3b, and the fourth combustion control region IV, which is a hot water supply output of G4a to G4b, are higher. Repeat for burner b and third burner c.

  In the case where the water heater is a water heater having a hot water supply mode for a bathtub, when the hot water supply mode is selected, the combustion control means performs upper limit combustion in the fourth combustion control region IV in FIG. It is normal to perform combustion at the amount G4b. For this reason, in the hot water mode, the noise of K1 (dB) or more is continuously generated. That is, in the conventional water heater, up to K1 (dB) of about the operating noise has occurred repeatedly or continuously, from environmental, improvement is required.

  From such a viewpoint, Patent Document 1 describes a combustion apparatus that suppresses the generation of driving noise (noise) during driving. This combustion device uses a plurality of burner sections as combustion burner sections to adjust the combustion amount within the high combustion amount range, and reduces the number of combustion burner sections compared to that during high combustion control to reduce the combustion amount. Combustion control means for performing combustion control by executing low combustion control that adjusts within the amount range, and the combustion control means sets the upper limit value of the low combustion amount range to be less than the lower limit value of the high combustion amount range When the target combustion amount is within the intermediate combustion amount range that is greater than or equal to the upper limit value of the low combustion amount range and less than the lower limit value of the high combustion amount range, the high combustion control and the low combustion control are periodically switched. By executing the control, intermediate combustion control for adjusting the average combustion amount of the burner within the intermediate combustion amount range is executed.

JP 2005-114323 A

  When the target combustion amount (hot water supply output) is within an intermediate combustion amount range that is greater than or equal to the upper limit value of the low combustion amount range and less than the lower limit value of the high combustion amount range, by performing a low combustion control periodically switched, so that to execute the intermediate combustion control for adjusting the average firing rate of the burner in the intermediate combustion amount range. That is, within this intermediate combustion amount range, the flame length of the burner is shorter than that at the upper limit combustion amount, and as a result, the amount of air supplied from the combustion air supply fan is also less than that at the upper limit combustion amount. Tesumi, the operating noise of the water heater can be suppressed to a low value. However, since this method is performed by periodically switching between high combustion control and low combustion control, combustion switching frequently occurs, and the durability of the equipment decreases with the increase in the number of combustion on / off, and the temperature of the hot water is reduced. The problem of fluctuation remains.

  On the other hand, in a normal water heater, as described above, the maximum operation sound (noise) is continuously generated in the hot water beam mode, and the operation duration time in the hot water beam mode is long. Therefore, although it has been raised as a problem to reduce the operation noise in the hot water beam mode, the combustion apparatus described in Patent Document 1 does not give any particular consideration from such a viewpoint.

  This invention is made in view of the above situations, and provides the water heater which can reduce the grade of the driving | running sound (noise) at the time of hot water operation with a comparatively long operation continuation time. Is an issue.

  The water heater according to the present invention has a combustion section provided with two or more burners, a heat exchanger that performs heat exchange between the combustion gas from the burner and water, and the temperature of the heat exchanger is increased. A hot water pipe for supplying hot water to the outside; and at least combustion control means for performing combustion control on each burner with a combustion amount between a lower limit combustion amount and an upper limit combustion amount, wherein the hot water pipe supplies hot water to the hot water tap. A hot water pipe for supplying a hot water pipe for supplying hot water and a hot water pipe for supplying hot water to a bathtub and for guiding the flow of the hot water to the hot water pipe for hot water by turning on the combustion control means. A water heater provided with a mode selection switch, wherein the combustion control means further comprises a silent setting switch, and the combustion control means has the hot water mode selection switch ON, and When the sound setting switch is ON, control combustion of all burners within a predetermined range from the lower limit combustion amount of each burner to the intermediate combustion amount, or fix the combustion amount of all burners to the lower limit combustion amount of each burner Silent hot water mode that performs combustion control is executed.

  In the above water heater, hot water beam mode selection switch is the ON, and when quiet setting switch is ON, the operation in the silent water beam mode. In the silent hot water beam mode, all burners are controlled to burn within a predetermined range (preferably a range slightly above the lower limit combustion amount) from the lower limit combustion amount of the burner to the intermediate combustion amount, or the lower limit combustion amount of the burner Is controlled in combustion. In that state, the flame length of all the burners is shorter than the flame length when any or all of the burners are burning at the upper limit combustion amount, so that the amount of air supplied from the combustion air supply fan can be reduced. As a result, both the noise of the combustion air supply fan and the noise accompanying the flame are suppressed. Thereby, the operation sound generated by the water heater in the hot water mode is suppressed to a low level.

  In the water heater according to the present invention, the same operation mode as that of the conventional water heater is adopted in the general hot water supply mode for supplying hot water to a hot water tap or the like. Therefore, temporarily, any or all of the burners may burn at the upper limit combustion amount. At that time, the rotational speed of the combustion air supply fan increases and the noise accompanying the flame length also increases. However, in the hot water supply operation, the operation continuation time at the burner upper limit combustion amount in the general hot water supply mode is short, and this does not substantially cause a problem. The operation mode that keeps operating for a relatively long time in the hot water supply operation is “hot water beam” to the bath, and in the water heater according to the present invention, substantial noise is reduced by reducing the operation noise during hot water operation. The problem can be solved. In addition, since the switching between burning and stopping of the burner can be reduced in the silent hot water heating mode, durability as a device is maintained, and fluctuations in the hot water temperature do not occur.

  In the general hot water supply mode, there is a possibility that the required hot water amount and the required hot water temperature may be changed every time by the user. Therefore, the combustion control as in the present invention that fixes the output in a narrow range is changed to the general hot water supply mode. When applied, stable operation is not possible. However, in the hot water filling mode, the required amount of hot water and the required hot water temperature are not changed during use, so that stable operation is possible even with combustion control as in the present invention. From this point of view, it is an important point of the present invention that the application range is specialized in the hot water mode.

  In another aspect of the water heater according to the present invention, the water heater includes a flow rate sensor that detects the presence or absence of the flow rate of the hot water pipe for general hot water supply, and the combustion control unit is configured to detect when the flow rate sensor detects the flow rate. In addition, the present invention is characterized by comprising a mode in which the execution of the silent hot water hot water mode is stopped and the normal hot water hot water mode is executed.

  There are three modes of use of the water heater: a general hot water supply mode, a hot water beam mode, and a combined mode of the general hot water supply mode and the hot water beam mode. In the combined mode, the amount of supplied water increases by the amount of hot water that is diverted to the hot water tap, and the required temperature rise may not be obtained with the hot water supply output in the silent hot water beam mode. The above aspect of the water heater according to the present invention avoids the inconvenience, and when hot water is flowing through the hot water pipe for general hot water supply, the execution of the silent hot water beam mode is stopped and the normal hot water beam mode is set. By executing this, the hot water supply output is increased and hot water at the required temperature is obtained. However, in the normal hot water mode, all the burners burn at the upper limit combustion amount, so that the generated sound volume increases. However, this is temporary, and when the hot water from the hot water tap is stopped, the original silent hot water heating mode is also restored, so this is not a big problem in terms of noise.

  In another aspect of the water heater according to the present invention, the water heater includes a thermometer capable of measuring the temperature of hot water flowing through a hot water hot water pipe, and the combustion control means executes the silent hot water beam mode. When the measured value of the thermometer exceeds a predetermined value, any one or more of the burners are stopped and the measured value of the thermometer is a predetermined value. When the following condition is reached, the silent hot water heating mode by the combustion of all the burners is executed again.

  During the use of the water heater, there may be a case where the feed water flow rate does not reach a predetermined amount due to a lack of feed water pressure. In this case, if the hot water supply output is constant, the hot water temperature becomes higher than a predetermined temperature even during operation in the silent hot water beam mode. The above-described aspect of the water heater according to the present invention avoids this, and when the hot water temperature becomes higher than a predetermined temperature, any one or one or more combustion is stopped, and the hot water supply output Is temporarily reduced so that the temperature of the hot water flowing through the hot water piping for hot water does not rise above a predetermined temperature.

  In still another aspect of the water heater according to the present invention, the water heater includes a thermometer capable of measuring the temperature of hot water flowing through the hot water hot water pipe, and the combustion control means supplies water supplied to the heat exchanger. The water supply amount control means for controlling the amount is further provided, and when the silent hot water beam mode is executed and the measured value of the thermometer becomes a predetermined value or less, the water supply amount The controller is operated to limit the amount of water supplied to the heat exchanger, and when the measured value of the thermometer exceeds a predetermined value, the water supply amount controller is operated again. The restriction on the amount of water supplied to the heat exchanger is canceled.

  During use of the water heater, the water supply flow rate may increase beyond a predetermined value. In that case, if the hot water supply output is constant, the hot water temperature does not rise to a predetermined temperature. The above-described aspect of the water heater according to the present invention avoids that, and executes control to limit the amount of water supplied to the heat exchanger when the feed water flow rate exceeds a predetermined value. Only the amount of water commensurate with the hot water supply output is sent to the heat exchanger to prevent the temperature of the hot water sent to the bathtub from decreasing.

  In still another aspect of the water heater according to the present invention, the combustion control means includes a reheating mode selection switch, and the combustion control means includes the reheating mode selection switch being ON and the silent setting switch being ON. Means for executing a silent reheating mode for performing combustion control of the reheating burner in a predetermined combustion amount range between the lower limit combustion amount and the upper limit combustion amount of the burner used for reheating. It is characterized by.

  In this aspect, even in the reheating mode in which the hot water stored in the bathtub is repelled, the operation sound (noise) generated by the water heater can be suppressed.

  In the water heater according to the present invention, heat from a part or all of the burners including the reheating burner is exchanged with water, and the water (hot water) is circulated to a bathroom or a room to perform heating or the like. A so-called heating / water heater is also included. Furthermore, in the present invention, the term “switch” is not only a mechanical ON-OFF switch, but also a changeover switch on software that achieves the ON-OFF function by touching the display on the setting screen. Of course included.

  The water heater according to the present invention can reduce the operation noise (noise) during hot water operation with a relatively long operation duration, and effectively solve the substantial noise problem associated with the operation of the water heater. Can do. In addition, since the switching between burning and stopping of the burner can be reduced in the silent hot water heating mode, durability as a device can be maintained, and fluctuations in the hot water temperature can be prevented.

The figure which shows typically the structure of one Embodiment of the water heater by this invention. The flowchart which shows an example of the driving | operation operation in the combustion control means of the water heater shown in FIG. Schematic which shows an example of the controller in the water heater shown in FIG. It is a graph which shows the characteristic of the driving | running | working sound in a water heater, and shows the relationship with a target noise value. The graph which shows the characteristic of the driving sound at the time of silent sound hot water beam mode. The graph which shows the characteristic of a driving | running sound when a request | requirement hot-water supply output is small in silent sound hot water beam mode. The graph which shows the temperature rise degree of water in the case where the feed water flow rate is different in the silent hot water beam mode. The flowchart which shows an example of driving | operation operation when there are few water supply flow rates. The flowchart which shows an example of driving | operation operation when there are too many feed water flow rates. The graph which shows the relationship between the hot-water supply output and driving | running | working sound in the conventional water heater.

  Hereinafter, the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a diagram schematically showing the structure of an embodiment of a water heater according to the present invention. The water heater 1 includes a combustion unit 10, a heat exchanger 20, a pipe group of water and hot water, and a combustion control means 30. A part of the piping group forms a circulation pipeline with the bathtub 2. Each will be described below.

  The combustion unit 10 includes two main burners 11 and 12 and a reheating burner 13. The heat exchanger 20 is composed of a main heat exchanger 21 with respect to the main burner 11, the fired heat exchanger 22 to follow for fired burner 13 follow. In the illustrated example, in order to make the illustration easy to understand, the main burner is illustrated with two burners 11 and 12 provided side by side, but three or four burners may be provided in parallel.

  Further, the combustion unit 10 is provided with a combustion air supply fan 14, which supplies combustion air to all the burners 11, 12, 13 regardless of whether or not the burner is burning. Is done. In the illustrated example, the combustion air is supplied to all the burners 11, 12, 13 with one combustion air supply fan 14, but there are two combustion air supply fans for the main burners 11, 12. There are cases where the air is divided into a combustion air supply fan and a combustion air supply fan for the reheating burner 13. Although not shown, the water whose temperature has been increased by heat exchange in either or both of the main heat exchanger 21 and the reheating heat exchanger 22 is circulated in a bathroom, a living room, etc., and used for indoor heating, drying, and the like. You can also

  Water is sent from the water supply pipe 41 into the main heat exchanger 21. The water supply pipe 41 is provided with a flow rate adjustment valve 42. Combustion gas is supplied to the combustion unit 10 from the gas supply pipe 61, and combustion air is sent from the combustion air supply fan 14, and each burner burns to generate combustion gas. Combustion gas main burner 11, 12 is generated by combustion, and water and heat exchange through the water supply pipe 41 to heat the water in the main heat exchanger 21. The heated hot water is sent to a hot water tap (not shown) in a kitchen or a washroom through a hot water pipe 43 and a subsequent hot water pipe 44 for general hot water supply. In this example, the general hot water supply hot water pipe 44 is provided with a flow rate sensor 45.

  The gas supply pipe 61 is provided with an original gas solenoid valve 62, a gas proportional valve 63, and a switching solenoid valve 64. The original gas solenoid valve 62 supplies and stops gas from the gas supply source to the gas supply line 61, the gas proportional valve 63 controls the amount of gas supplied to the combustion unit 10, and the switching solenoid valve 64 is the combustion unit. Selection of 10 combustion regions, that is, burners 11, 12, and 13 to which combustion gas is supplied are selected.

  From the upstream side of the flow rate sensor 45 of the hot water pipe 43, a hot water hot water pipe 48 branches off. The hot water hot water pipe 48 is connected to the hot water circulating pipe through a hot water solenoid valve 49 and a check valve 50. The hot water circulating pipe is connected to an outgoing pipe 51 through which the hot water is sent to the bathtub 2 through the reheating heat exchanger 22 and a return pipe 52 from which the hot water is returned from the bathtub 2 to the reheating heat exchanger 22. Composed. The hot water hot water pipe 48 is connected to the return pipe 52. A pump 53 is provided in the return line 52. When the pump 53 is activated, hot water circulates between the bathtub 2 and the reheating heat exchanger 22. The outgoing pipe 51 is provided with a temperature sensor 54. In the present invention, the forward pipe 51 and the return pipe 52 constitute a part of the hot water hot water pipe 48.

  FIG. 3 shows the controller 70. The controller 70 is a part of the combustion control means 30, and an operation signal from the controller 70 is sent to the combustion control means 30, and the combustion control means 30 performs control according to the operation signal to the combustion unit 10, the valve, and the like. It performs with respect to the said piping group containing.

  The controller 70 includes an operation switch 71, a hot water beam switch 72, a silent setting switch 73, a reheating switch 74, a hot water temperature setting button 75, and a display unit 76. The controller 70 may be the same as the controller used in a conventional water heater except that the controller 70 includes a silent setting switch 73. Further, the controller 70 may be configured such that necessary information for operation is displayed on the display unit 76 and necessary information is sent to the combustion control means 30 by touching the displayed item. As an example, by touching the “silent on / off” item displayed on the screen, a function of performing the same operation as the ON / OFF of the hot water switch 72 may be provided on the software.

  The operation of the water heater 1 will be described with reference to the flowchart of FIG. By turning on the operation switch 71, the water heater 1 starts operation in the general hot water supply operation mode. In the general hot water supply operation mode shown in S10, the combustion control means 30 closes the hot water solenoid valve 49 of the hot water hot water pipe 48 and closes the switching electromagnetic valve 64 for the reheating burner 13. Further, the flow rate adjustment valve 42 attached to the water supply pipe 41 is fully opened. When a hot water tap (not shown) is opened, an amount of water corresponding to the opening of the hot water tap flows from the water supply pipe 41.

  The combustion control means 30 controls the gas proportional valve 63 and the switching electromagnetic valve 64 so as to obtain a combustion amount (hot water supply output) sufficient to raise the temperature of the water flowing into the temperature set by the hot water temperature setting button 75. The combustion control of the main burners 11 and 12 is performed, and the rotational speed of the combustion air supply fan 14 is controlled so that the amount of air necessary for combustion is supplied. An example of burner control is shown in FIG. This control may be the same as the burner control in the conventional water heater described based on FIG.

  In Figure 4, the level hot water output is small, only the main burner 11 is burned, corresponding to the hot water supply load from the lower combustion of the main burner 11 to the upper limit combustion amount. Combustion air necessary for burning the amount of gas supplied to the main burner 11 is sent from the combustion air supply fan 14 to the main burner 11. The combustion air amount required as the hot water supply load increases increases, the rotational speed of the combustion air supply fan 14 also gradually increases, becomes gradually large operating noise. Further, as described above, the air from the combustion air supply fan 14 is also sent to the unburned main burner 12 and the reheating burner 13, so that the main burner 11 is burning at the upper limit combustion amount. The number of revolutions of the combustion air supply fan 14 becomes very high, and as shown in FIG. 4, for example, an operation sound of about 48 dB is generated.

  When the required hot water supply output further increases, the combustion control means 30 switches the combustion burner to the main burner 12. As shown in the figure, the main burner 12 has more combustion nozzles than the main burner 11, and the flame length of each combustion nozzle when the hot water supply output required for the main burner 12 as a whole is given is the main burner 11. Becomes shorter than the flame length when burning at the upper limit combustion amount. Therefore, the rotational speed of the combustion air supply fan 14 can be reduced, and the operation sound at the time when the combustion burner is switched to the main burner 12 becomes low again. When the required hot water supply output is further increased, a larger amount of combustion is required, and when the main burner 12 reaches the upper limit combustion amount, the rotational speed of the combustion air supply fan 14 is very high as in the case of the main burner 11. The engine speed is high and a driving sound of about 48 dB is generated.

  If the request hot water output is further increased, the combustion control means 30 is mainly a burner 11 and to select both the 12 as a combustion burner, for example, to perform a combustion of up to about the hot water output G4b. Also at this time, a driving sound of about 48 dB is generated at that time.

  However, in the operation in the above-described general hot water supply operation mode (that is, a mode in which hot water is supplied from a hot water tap such as a faucet), the operation time is relatively short, for example, at a large volume such as 48 dB. There are few cases where the driving noise of the vehicle becomes an environmental problem as noise.

  In S11, the hot water switch 72 of the control panel 70 is turned ON by the user. Responding to this, the combustion control means 30, is opened the pouring solenoid valve 49 of the water beam hot water pipe 48, the combustion of the main burner 11, 12. In the example shown in FIG. 4, there is a possibility that the required hot water supply output may increase up to G4b, and in order to satisfy this, combustion control is performed. The means 30 causes all the main burners 11 and 12 to perform combustion at the upper and lower combustion amounts. Further, the number of combustion nozzles is also the maximum, and from these facts, the operation sound of the water heater 1 when the hot water beam switch 72 is turned on is also at a level exceeding 48 dB. And since it takes a long time to supply a predetermined amount of hot water to the bathtub 2, the operation sound of the water heater 1 in the hot water mode may be an environmental problem as noise. In order to avoid this and reduce the operation sound to, for example, the target noise value and operate the water heater 1, a silent setting switch 73 is provided in the water heater according to the present invention.

  In S12, the combustion control means 30 determines in advance whether or not the silent setting switch 73 is ON. When the silent setting switch 73 is not ON, the combustion control means 30 continues the above-described normal hot water operation mode, and controls each burner as described with reference to FIG. 4 (S13). When the silent setting switch 73 is ON, the combustion control means 30 executes the silent hot water heating mode of S14.

  That is, when the hot water switch 72 is ON and the silent setting switch 73 is ON, the combustion control means 30 performs ignition of the main burners 11 and 12, and FIG. 5 (a) or FIG. As shown in b), the combustion of all the burners is controlled below the combustion amount that can achieve the target noise value. In the example shown in FIG. 5A, the combustion control means 30 is configured so that the hot water supply output is within the range of G4a to G4c, that is, within a predetermined range from the lower limit combustion amount of each burner to the intermediate combustion amount. By controlling the gas supply amount to all the burners and the rotation speed of the combustion air supply fan 14 associated therewith, the operation sound of the water heater 1 is set to be equal to or lower than the target noise value. In the example shown in FIG. 5B, the gas supply amount to all the burners and the accompanying combustion air supply fan 14 so that the hot water supply output becomes G4a, that is, each burner becomes the lower limit combustion amount. By controlling the number of rotations, the operation sound of the water heater 1 is set to be equal to or lower than the target noise value.

  The combustion control means 30 determines whether or not a predetermined amount of hot water supply to the bathtub 2 has been completed in S15. When it is finished, the combustion control means 30 cancels the hot water filling mode in S16 and finishes the hot water filling. Specifically, combustion of the burners 11 and 12 is stopped, and the hot water solenoid valve 49 of the hot water hot water pipe 48 is closed.

  When the operation is continued in the silent hot water beam mode, hot water may be used from the hot water tap connected to the general hot water supply hot water pipe 44. At that time, the amount of water supplied is increased by the amount of hot water that is diverted to the hot water tap, and the required temperature rise may not be obtained with the hot water supply output in the silent hot water beam mode. S20 to S22 are provided to cope with this, but can be omitted.

  In S <b> 20, the combustion control means 30 determines whether or not the general hot water supply hot water pipe 44 has a flow rate based on a signal from a flow rate sensor 45 attached to the general hot water supply hot water pipe 44. If there is no flow rate, the process returns to S14 and the silent hot water hot water mode is continued. If there is a flow rate, the process proceeds to S21, and the combustion control means 30 executes the general hot water supply operation mode and the normal hot water beam mode, and executes the burner control in the manner shown in FIG. In this state, the combustion control means 30 determines whether or not the flow rate is 0 in the hot water supply hot water piping 44 in S22. If the flow rate is 0, the combustion control means 30 returns to S14 and continues the silent hot water heating mode.

  By performing the steps of the S20 to S22, a person using the hot water from the hot water faucet or the like, it can be eliminated from having discomfort due to the temperature drop of the hot water.

  In said water heater 1, the user can also use the reheating mode which reheats the hot water of the bathtub 2. FIG. When the reheating switch 74 of the control panel 70 is turned on, the combustion control means 30 performs the combustion of the reheating burner 13 and drives the pump 53 attached to the return line 52. Accordingly, the hot water in the bathtub 2 is sucked by the pump 53 and flows through the return pipe 52, and is heated by exchanging heat with the combustion gas of the reheating burner 13 by the reheating heat exchanger 22. It returns to the bathtub 2 again through the pipe line 51.

  Normally, in this type of water heater, when reheating, is set to fired burner 13 follow to operate at the upper limit combustion amount. In that case, the firing control means 30 operates the combustion air supply fan 14 at a high rotational speed, and as described above, the operation noise of the water heater becomes as high as about 48 dB, for example. In the water heater 1 according to the present invention, in order to avoid a high driving noise during reheating, when the reheating switch 74 is ON and the silent setting switch 73 is ON, the firing control means 30 The combustion of the reheating burner 13 which is a burner used for burning is controlled in a predetermined range from the lower limit combustion amount to the intermediate combustion amount, or the burner combustion amount is fixed to the lower limit combustion amount It is also possible to provide a so-called silent chasing mode that performs combustion control. As a result, it is possible to perform a reheating operation with the target noise value or less. Further, in the example shown in FIG. 1, only one reheating burner 13 is provided. However, similar to the main burners 11 and 12, the reheating burner 13 may be divided into two or more. In this case, the same combustion control as described above is performed.

  In the water heater 1 described above, there may be a case where the flow rate of the water supply from the water supply pipe 41 does not reach a predetermined amount due to external reasons such as insufficient supply water pressure. In that case, at the minimum hot-water supply output G4a (for example, 23 kW) in the control shown in FIG. 5A or FIG. FIG. 7 is a graph showing an example of the temperature rise of the feed water when the feed water flow rate is different when the hot water supply output is taken on the horizontal axis and the difference between the hot water temperature and the feed water temperature is taken on the vertical axis. If the water supply flow rate is only 15 L / min and the temperature rise of 22 ° C. occurs even at the minimum hot water supply output G4a (for example, 23 kW), as shown by the point P in FIG. In about 25 ° C.), the temperature of hot water supplied to the bathtub 2 rises to 25 ° C. + 22 ° C. = 47 ° C.

  In order to avoid this, in the preferred embodiment of the water heater 1 according to the present invention, as shown in the flowchart of FIG. 8, the combustion control means 30 detects the temperature from the temperature sensor 54 attached to the forward line 51 in S30. A signal is obtained constantly or at regular time intervals to determine whether the hot water temperature exceeds a predetermined temperature. If not, the process returns to S14. If it exceeds, that is, if the hot water temperature is equal to or higher than the predetermined temperature, the combustion control means 30 executes the combustion stop of any one of the burners in S32. In S32, it is determined again whether the hot water temperature has become equal to or lower than the predetermined temperature. If NO, that is, if the temperature still exceeds the predetermined temperature, the process returns to S31 and a burner for stopping combustion is added. Then repeat it. At that time, the hot water supply output pattern is any one of B, C, and D shown in FIG. 6 (a) or FIG. 5 (b). FIG. 6A shows a case where combustion control of each burner is performed within a predetermined range from the lower limit combustion amount to the intermediate combustion amount of each burner. FIG. 6B shows the combustion amount of each burner. This is a case where the combustion control is fixed to the lower limit combustion amount of the burner. In the embodiment of FIG. 6B, since it is considered that a situation that requires one burner to be operated at the lower limit combustion amount does not normally occur, the pattern D is omitted. When the hot water temperature is equal to or lower than the predetermined temperature, the process returns to S14, combustion control means 30 executes the silent water beam mode by again the combustion of the main burner 11.

  As another execution mode, when the combustion control means 30 determines in S30 that the hot water temperature exceeds the predetermined temperature, the combustion of the main burners 11 and 12 is stopped, and the hot water temperature is predetermined by flowing fresh water. When the temperature falls below the temperature, or when a predetermined period of time has passed when fresh water flows, the process returns to S14, and the silent hot water mode by the combustion of the main burners 11 and 12 may be executed again.

  Conversely, there may be cases where the feed water flow rate is too high. In that case, as shown in the graph of the feed water flow rate of 25 L / min in FIG. 7, the hot water temperature may not be sufficiently increased even if the combustion control is performed at the maximum hot water supply output. For example, if the water supply temperature is about 10 ° C. in winter, even if combustion control is performed with the maximum hot water supply output G4c (for example, 28 kW) in the silent hot water beam mode, if the water temperature rise is about 16 ° C., then 16 ° C. + 10 The temperature of hot water supplied to the bathtub 2 rises only up to ℃ = 26 ℃.

  In order to cope with this, in another preferred embodiment of the water heater 1 according to the present invention, as shown in the flowchart of FIG. 9, the combustion control means 30 is in S40 when the silent hot water heating mode is being executed. Then, it is determined whether or not the temperature of the hot water from the temperature sensor 54 attached to the outgoing pipe 51 is equal to or lower than a predetermined temperature. If NO, the process returns to S14. When the measured value of the temperature sensor 54 is equal to or lower than a predetermined temperature, the flow control valve 42 provided in the normally open water supply pipe 41 is commanded to reduce the flow rate, and the water to the heat exchanger 20 is sent in S41. The opening degree of the valve 42 for limiting the flow rate is reduced. In S42, it is determined whether or not the hot water temperature has exceeded a predetermined temperature. If NO, that is, if it is still below the predetermined temperature, the flow returns to S41 to further narrow the flow rate adjustment valve 42. Then repeat it. When the hot water temperature exceeds the predetermined temperature, the combustion control means 30 fixes the opening degree of the flow rate adjustment valve 42 in S43, and in that state, returns to S14, and the silent hot water heating mode by the combustion of the main burners 11 and 12 is performed. Continue to execute.

  In addition, when there is too much water supply flow volume and the warm water supplied to the bathtub 2 does not rise to a desired temperature, the hot water supply to the bathtub 2 is continued without adopting the operation according to the flowchart of FIG. Of course, after the hot water is finished, it is possible to operate in the above-described reheating mode so as to raise the temperature in the bathtub 2 to a desired temperature.

1 ... Water heater,
2 ... tub,
10 ... combustion part,
11, 12 ... main burner,
13 ... Reheating burner 14 ... Fan for supplying combustion air,
20 ... heat exchanger 21 ... main heat exchanger,
22 ... Reheating heat exchanger,
30 ... Combustion control means,
41 ... water supply piping,
42 ... Flow control valve,
43 ... Hot water piping,
44 ... Hot water piping for general hot water supply,
45 ... Flow sensor,
48 ... Hot water piping for hot water
49. Solenoid solenoid valve,
50 ... Check valve,
51. Outbound pipeline,
52 ... Return pipeline,
53 ... pump,
54 ... temperature sensor,
61 ... Gas supply line,
62 ... Former gas solenoid valve,
63 ... Gas proportional valve,
64 ... switching solenoid valve,
70 ... Controller,
71: Operation switch,
72 ... Hot water switch,
74 ... Reap switch
75 ... Hot water temperature setting button,
76: Display section.

Claims (5)

A combustor having two or more burners, a heat exchanger for exchanging heat between the combustion gas from the burner and water, and hot water for supplying hot water heated by the heat exchanger to the outside A hot water pipe for general hot water supply for supplying hot water to a hot water tap, and at least combustion control means for performing combustion control for each burner with a combustion amount between a lower limit combustion amount and an upper limit combustion amount And a hot water hot water pipe for supplying hot water to the bathtub, and a hot water mode selection switch for guiding the flow of the hot water to the hot water hot water pipe by turning on the combustion control means. A water heater,
The combustion control means further includes a silent setting switch, and the combustion control means determines from the lower limit combustion amount of each burner when the hot water mode selection switch is ON and the silent setting switch is ON. It is characterized by performing a silent hot water beam mode that performs combustion control of all burners within a predetermined range up to the intermediate combustion amount, or performs combustion control that fixes the combustion amount of all burners to the lower limit combustion amount of each burner. Water heater to do.   2. The water heater according to claim 1, wherein the water heater is provided with a flow rate sensor that detects the flow rate of the hot water piping for the general hot water supply, and the combustion control unit detects the flow rate. A hot water heater comprising: a mode in which execution of the silent hot water beam mode is stopped and a normal hot water beam mode is performed.   2. The water heater according to claim 1, wherein the water heater includes a thermometer capable of measuring the temperature of hot water flowing through a hot water hot water pipe, and the combustion control means executes the silent hot water beam mode. When the measured value of the thermometer exceeds a predetermined value, any one or more of the burners are stopped and the measured value of the thermometer is a predetermined value. When the following conditions are met, the silent water hot water mode is performed again by the combustion of all the burners.   2. The water heater according to claim 1, wherein the water heater is provided with a thermometer capable of measuring the temperature of hot water flowing through a hot water pipe for hot water, and the combustion control means supplies water supplied to the heat exchanger. The water supply amount control means for controlling the amount is further provided, and when the silent hot water beam mode is executed and the measured value of the thermometer becomes a predetermined value or less, the water supply amount The controller is operated to limit the amount of water supplied to the heat exchanger, and when the measured value of the thermometer exceeds a predetermined value, the water supply amount controller is operated again. The hot water heater is characterized in that the restriction on the amount of water supplied to the heat exchanger is canceled.   The hot water heater according to any one of claims 1 to 4, wherein the combustion control means further includes a reheating mode selection switch, and the combustion control means has the reheating mode selection switch turned on. When the silent setting switch is ON, the combustion control of all burners is performed within a predetermined range from the lower limit combustion amount of the burner used for reheating to the intermediate combustion amount, or the combustion amount of all the burners is set. A water heater, further comprising means for executing a silent chasing mode in which combustion control is fixed to a lower limit combustion amount of each burner.

Images