JP2017122533A - Bath water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bath water heater capable of preventing degradation of bath reheating efficiency by reducing interruption of combustion at a bath reheating side while suppressing generation of dew condensation in simultaneous combustion, in a structure in which heat flows from a hot water supply side to a bath reheating side.SOLUTION: A bath water heater includes a heat exchanger 22 for hot water supply, a hot water supply burner 21 for heating the heat exchanger 22 for hot water supply, a heat exchanger 32 for bath reheating thermally connected to the heat exchanger 22 for hot water supply through a fin 25 and the like, a bath burner 31 for heating the heat exchanger 32 for bath, and a common gas proportional valve 42 for the hot water supply burner 21 and the bath burner 31. In a case when the hot water supply and bath reheating are simultaneously used, an opening of the proportional valve is controlled for the hot water supply side with priority, whether dew condensation occurs or not in the heat exchanger 32 for bath reheating is determined on the basis of a bath return temperature, a combustion amount of the bath burner 21, and further an amount of heat transferred from a side of the heat exchanger 22 for hot water supply to the heat exchanger 32 for bath reheating, and the gas supply to the bath burner 31 is blocked when the dew condensation is determined.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bath water heater that controls the amount of gas supplied to a hot water supply burner and a bath reheating burner with a common proportional valve.

  In bath water heaters, the provision of gas proportional valves for adjusting the supply of combustion gas separately to the hot water supply burner and the bath reheating burner is not performed due to demands for cost reduction, etc. A common gas proportional valve is provided. When the hot water supply operation and the bath reheating operation are performed at the same time and the hot water supply burner and the bath reheating burner are simultaneously burned, the combustion amount of the hot water supply burner is given priority so that the hot water supply temperature becomes the target temperature. Thus, the opening degree of the gas proportional valve is controlled.

  If the opening of the gas proportional valve during simultaneous combustion is small due to priority on the hot water supply side and the temperature of the bath water returning from the bath is low, the temperature of the heat exchanger for bath reheating does not rise so much and combustion Moisture in the exhaust is cooled by the heat exchanger for bathing, and condensation occurs.

  Therefore, various controls for preventing the above-mentioned condensation have been proposed. For example, in Patent Document 1 described below, when simultaneous combustion is performed, the possibility of condensation is determined based on the temperature of circulating water from a bath-heating heat exchanger, and it is determined that there is a possibility of condensation. A technique for temporarily interrupting combustion of a reheating burner is disclosed.

  Further, Patent Document 2 below discloses a bath reheating heat when the temperature of water entering the heat exchanger for reheating the bath is lower than a predetermined temperature and the opening of the gas proportional valve is equal to or lower than a predetermined temperature at the time of simultaneous combustion. Control is disclosed in which the flow rate is reduced by reducing the speed of a circulation pump that circulates bathtub water through an exchanger. By reducing the flow rate of the bathtub water that flows through the bath-heating heat exchanger, the temperature drop of the bath-heating heat exchanger is reduced to prevent condensation.

JP 2001-33099 A Japanese Utility Model Publication No. 2-124442 Patent No. 4071224

  If the can body (combustion chamber) for storing the burner for heating the hot water supply heat exchanger and the can body for storing the burner for heating the heat exchanger for bathing are completely separated, the cost increases. Therefore, these burners are divided into left and right inside a common can body, and a hot water supply heat exchanger and a bath reheating heat exchanger are arranged above each, and a hot water supply heat exchanger and a reheating bath are disposed. There is a structure in which the fins of the heat exchanger are connected and the inside of the can below the fins is partitioned by a partition plate to form two combustion chambers (see, for example, Patent Document 3).

  When a combustion chamber with such a structure is used, the heat from the combustion of the hot water burner is transferred to a certain degree to the heat exchanger for reheating the bath. The occurrence of dew condensation is different from the conventional one. For this reason, if the possibility of condensation is determined based on the criteria disclosed in Patent Document 1, the combustion of the bath-burning burner is interrupted even though there is still room before the occurrence of condensation, and the bath The efficiency of sowing will be reduced more than necessary.

  The present invention has been made to solve the above-described problems. In a structure in which heat flows from a hot water supply side to a heat exchanger for reheating a bath, the occurrence of dew condensation during simultaneous combustion is suppressed, and It is an object of the present invention to provide a bath water heater that can reduce the interruption of combustion on the burning side and prevent a decrease in the efficiency of reheating the bath.

  The gist of the present invention for achieving the object lies in the inventions of the following items.

[1] a heat exchanger for hot water supply;
A hot water supply burner for heating the hot water supply heat exchanger;
A heat exchanger for bathing, which is thermally connected to the heat exchanger for hot water supply,
A bath burner for heating the bath-heating heat exchanger;
A proportional valve for adjusting the amount of gas supplied to the hot-water supply burner and the bath burner;
A first shutoff valve for switching whether to supply gas to the hot water burner;
A second shut-off valve for switching whether to supply gas to the bath burner;
A temperature sensor for detecting a temperature of water entering the heat exchanger for bathing,
A circulation pump that circulates the bath water via the heat exchanger for bathing when bathing,
A controller for controlling the combustion of the hot water burner and the bath burner,
The controller controls the opening of the proportional valve with priority given to the hot water supply side when performing hot water supply and bath reheating at the same time, and further adds the hot water supply to the detected temperature of the temperature sensor and the combustion amount of the bath burner. In consideration of the amount of heat transmitted from the heat exchanger side to the bath-heating heat exchanger, it is determined whether or not condensation occurs in the bath-heating heat exchanger. A bath water heater characterized by performing dew condensation prevention control that shuts off gas supply to the bath burner by means of a valve.

  In the above invention, since the hot water supply heat exchanger and the bath reheating heat exchanger are thermally connected, the heat on the hot water supply side is transferred to the bath reheating side during simultaneous combustion. Therefore, when performing hot water supply and bath reheating at the same time, bath reheating takes into account the amount of heat transmitted from the hot water supply heat exchanger to the bath reheating heat exchanger in addition to the return temperature of the bath and the combustion amount of the bath burner. It is determined whether or not condensation occurs in the heat exchanger. As examples of thermal connection, for example, when the heat exchanger for hot water supply and the fin of the heat exchanger for bathing are connected, or when the heat is transferred via the partition plate and the can itself and so on.

[2] The control unit determines the presence or absence of the dew condensation based on a temperature detected by the temperature sensor, a combustion amount of the bath burner, and a combustion amount of the hot water supply burner. Bath water heater.

  In the above invention, the amount of heat transferred from the hot water supply heat exchanger side to the bath reheating heat exchanger corresponds to the combustion amount of the hot water burner. Therefore, the presence or absence of condensation is determined based on the temperature detected by the temperature sensor, the combustion amount of the bath burner, and the combustion amount of the hot water supply burner.

[3] The bath water heater according to [1], wherein the controller determines the presence or absence of the dew condensation based on a temperature detected by the temperature sensor and a combustion amount of the hot water burner.

  In the above invention, the combustion amount of the bath burner is uniquely determined from the combustion amount of the hot water supply burner because the proportional valve is common. Therefore, the amount of combustion of the bath burner and the amount of heat transmitted from the hot water supply heat exchanger side to the bath reheating heat exchanger correspond to the combustion amount of the hot water supply burner. Therefore, the presence or absence of condensation is estimated from the bath return temperature and the combustion amount of the hot water supply burner.

[4] The hot-water supply burner is composed of a plurality of sub-burners,
The first shut-off valve can select the number and location of sub-burners that cut off the supply of combustion gas among the sub-burners,
The controller controls the combustion amount of the entire hot water burner by switching the opening of the proportional valve and the number and location of the sub burners that block the supply of combustion gas in the hot water burner,
The bath water heater according to [2] or [3], wherein in the determination of the presence or absence of condensation, which sub-burner is burning is considered.

  In the above invention, the amount of heat transmitted from the hot water supply heat exchanger side to the bath reheating heat exchanger depending on which sub-burner burns even if the combustion amount is the same (whether the burner is close to the bath reheating heat exchanger). Therefore, in determining whether or not condensation has occurred, which subburner is burned is taken into consideration.

[5] The bath hot water supply according to any one of [1] to [4], wherein the bath-heating heat exchanger is a latent heat recovery type heat exchanger that recovers latent heat and sensible heat. vessel.

[6] The bath water heater according to [5], wherein the temperature sensor detects a temperature of water entering the sensible heat recovery section of the bath-heating heat exchanger.

  In the said invention, in order to prevent dew condensation in a sensible heat collection | recovery part, it is desirable to determine the presence or absence of dew condensation based on the temperature of the incoming water to a sensible heat collection part.

  According to the bath water heater according to the present invention, since the amount of heat transmitted from the hot water supply side to the bath reheating side is taken into consideration, it is possible to reduce the interruption of combustion on the bath reheating side while suppressing the occurrence of condensation during simultaneous combustion. It is possible to prevent a decrease in the efficiency of bathing.

It is a figure which shows schematic structure of the bath water heater which concerns on embodiment of this invention. It is a figure which shows the schematic structure of a disassembled perspective view and combustion chamber of the bath water heater which concerns on embodiment of this invention. It is a figure which shows the relationship between the combustion amount (number) of a hot water supply side, and the opening degree of a gas proportional valve. It is a figure which shows determination based on correlation data. It is a flowchart which shows the process regarding the combustion control which the bath water heater which concerns on embodiment of this invention performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a bath water heater 10 according to an embodiment of the present invention. The bath water heater 10 is a hot water supply function that heats the water supply and supplies it to a predetermined tap, a pouring function that pours (fills in) the bathtub 2, and a bath chase that replenishes hot water (tub water) in the bathtub 2. Has a whispering function.

  The bath water heater 10 is provided with a vertically long cylindrical combustion chamber 13 into which air blown by the combustion fan 11 is sent from below and provided with an exhaust port 12 at the top. The combustion chamber 13 is partitioned into two chambers by a vertically-dividing partition plate 14, a hot water supply burner 21 is disposed on one side, and a bath burner 31 is disposed on the other side. The hot water supply burner 21 is composed of three burners A, burner B, and burner C in the order closer to the partition plate 14. The bath burner 31 is composed of one burner.

  Above the hot water supply burner 21, a hot water supply heat exchanger 22 for heating the supplied water with heat from the hot water supply burner 21 is disposed. Above the bath burner 31, a bath heat exchanger 32 for heating the bath water with heat from the bath burner 31 is arranged.

  The hot water supply heat exchanger 22 is arranged downstream of the hot water sensible heat exchanger 22a mainly by the sensible heat exchanger 22a for recovering sensible heat of the exhaust gas, and mainly in the latent heat of the exhaust gas. It is comprised with the latent heat exchanger 22b for hot water supply which collect | recovers.

  Similarly, the bath heat exchanger 32 is disposed downstream of the bath sensible heat exchanger 32a mainly by the sensible heat exchanger 32a for recovering the sensible heat of the exhaust, and mainly in the exhaust flow. It comprises a bath latent heat exchanger 32b that collects the latent heat of the exhaust.

  In the middle of the gas supply pipe 40 connected to the combustion gas supply source, there is provided a source gas electromagnetic valve 41 for switching whether or not the combustion gas from the supply source is shut off, and downstream of the hot water supply burner 21 and A gas proportional valve 42 for arbitrarily adjusting the amount of combustion gas supplied to the bath burner 31 is provided. The gas supply pipe 40 branches into four downstream of the gas proportional valve 42, and each of the branched gas supply pipes 40 reaches the burner A, the burner B, the burner C, and the bath burner 31 of the hot water supply burner 21.

  Each of the gas supply pipes 40 branched into four is provided with gas electromagnetic valves 43 to 46 for shutting off the supply of combustion gas. Specifically, the first hot water gas electromagnetic valve 43 is provided in the middle of the gas supply pipe 40 from the gas proportional valve 42 to the burner A, and the second hot water supply is provided in the middle of the gas supply pipe 40 from the gas proportional valve 42 to the burner B. The gas solenoid valve 44 is in the middle of the gas supply pipe 40 from the gas proportional valve 42 to the burner C, and the third hot water gas solenoid valve 45 is in the middle of the gas supply pipe 40 from the gas proportional valve 42 to the bath burner 31. A bath gas solenoid valve 46 is provided.

  A water supply pipe 50 that receives supply of water from a water supply source is connected to the inlet side of the hot water latent heat exchanger 22b, and the outlet side of the hot water latent heat exchanger 22b is connected to the inlet side of the hot water sensible heat exchanger 22a. A hot water supply pipe 51 leading to the hot water tap is connected to the outlet side of the sensible heat exchanger 22a for hot water supply. A water amount sensor 52 for detecting the amount of water supplied through the water supply pipe 50 is provided in the middle of the water supply pipe 50 leading to the inlet side of the hot water latent heat exchanger 22b. A water amount servo 53 for adjusting (restricting) is provided. A bypass pipe 54 branched from the water supply pipe 50 at a predetermined position downstream of the water amount servo 53 is joined and connected to a predetermined position of the hot water supply pipe 51. A bypass servo 55 for adjusting the amount of water supplied to the bypass pipe 54 is provided at a location where the bypass pipe 54 branches from the water supply pipe 50.

  At a predetermined location of the hot water supply pipe 51 between the outlet of the hot water sensible heat exchanger 22a and the junction of the bypass pipe 54, heat exchange for detecting the temperature of the hot water coming out of the hot water sensible heat exchanger 22a. A temperature sensor 56 is provided, and a hot water supply temperature sensor 57 for detecting a hot water supply temperature is provided at a predetermined location of the hot water supply pipe 51 downstream from the joining location of the bypass pipe 54.

  A bath return pipe 60 connects the entrance side of the bath latent heat exchanger 32 b of the bath heat exchanger 32 and the bathtub water intake 3 provided in the bathtub 2. The outlet side of the bath latent heat exchanger 32b is connected to the inlet side of the bath sensible heat exchanger 32a, and the outlet side of the bath sensible heat exchanger 32a is the bathtub water discharge port 4 provided in the bathtub 2. Are connected through a bath-out pipe 61.

  In the middle of the bath return pipe 60, a circulation pump 62 for circulating the bath water in the bath 2 through the bath heat exchanger 32 is provided. Furthermore, the bath return pipe 60 on the downstream side of the circulation pump 62 is provided with a running water switch 63 for detecting whether or not the bath return pipe 60 has a flow of hot water over a certain level.

  The bath return pipe 60 slightly upstream of the circulation pump 62 is provided with a bath return temperature sensor 64 for detecting the temperature of the bath water taken from the bathtub 2. A bath temperature sensor 65 for detecting the temperature of the bath water returning to the bathtub 2 through the bath tube 61 is provided in the middle of the bath tube 61.

  Furthermore, the bath return pipe 60 near the place where the bath return temperature sensor 64 is provided and the hot water supply pipe 51 near the place where the hot water supply temperature sensor 57 is provided are connected by a connecting pipe 66. Are inserted with a pouring electromagnetic valve 67 for switching the connecting pipe 66 between an open state and a shut-off state, and a check valve 68 for preventing a back flow from the bath return pipe 60 side to the hot water supply pipe 51. .

  In the combustion chamber 13, there is provided a drain receiver 15 that is disposed below the hot water latent heat exchanger 22 b and the bath latent heat exchanger 32 b, and receives the drain generated by these, and receives the drain receiver 15. The drain is sent to the neutralizer 17 through the recovery pipe 16, neutralized by the neutralizer 17, and then discharged from the discharge port.

  In addition, the bath water heater 10 includes a control unit that controls the operation of the bath water heater 10. Connected to the control unit is an operating unit that receives various settings and driving instructions from the user, and a remote controller that includes a display unit for displaying setting contents and driving conditions. The control unit is composed of circuits having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. as main parts, and the CPU executes various processes according to programs stored in the ROM. Thus, the operation as the bath water heater 10 is realized.

  FIG. 2 is a schematic cross-sectional view of the combustion chamber 13 and an exploded perspective view of the bath water heater 10. In the cross section of the combustion chamber 13 shown in FIG. 2, the latent heat exchanger and the sensible heat exchanger are not shown separately in the hot water supply heat exchanger 22 and the bath heat exchanger 32. Each of the hot water supply heat exchanger 22 and the bath heat exchanger 32 includes a heat receiving pipe 24 through which water supply and bath water pass, and a large number of fins (heat receiving plates) 25 attached around the heat receiving pipe 24. Yes. The fins 25 on the hot water supply heat exchanger 22 side and the fins 25 on the bath heat exchanger 32 side are connected in common. The fin 25 is provided with a cut from below at a position between the hot water supply heat exchanger 22 and the bath heat exchanger 32, and the upper end of the partition plate 14 is inserted into this cut and terminates.

  Since the heat exchanger 22 for hot water supply and the fin 25 of the heat exchanger 32 for bath are connected, when the hot water burner 21 is combusted, the heat on the side of the heat exchanger 22 for hot water supply passes through the fin 25 to some extent. It has a structure that is transmitted to the heat exchanger 32 (heat transfer 1 in FIG. 2). Further, heat is transferred from the hot water supply heat exchanger 22 to the bath heat exchanger 32 through the partition plate 14 partitioning the inside of the can (heat transfer 2 in FIG. 2), or through the outer copper inner cylinder through which the heat receiving pipe 24 passes. Heat is transferred (heat transfer 3 in FIG. 2). In this way, the hot water supply heat exchanger 22 and the bath heat exchanger 32 are thermally connected.

  Next, an outline of the hot water supply operation, the pouring operation, the bath reheating operation, and the operation in simultaneous use of the hot water supply and the bath reheating in the bath water heater 10 will be described.

<Hot-water supply operation>
When the hot water tap is opened and water flows through the water supply pipe 50, the water flow is detected by the water amount sensor 52. When the water amount sensor 52 detects water flow, the control unit ignites the hot water supply burner 21 and causes the hot water supply burner 21 to burn combustion gas. The water supply from the water supply source is heated by receiving the heat of the exhaust from the hot water burner 21 when passing through the hot water latent heat exchanger 22b and the hot water sensible heat exchanger 22a, and further mixed with the water supplied from the bypass pipe 54 After that, it is poured out into the tap. The control unit controls the combustion amount of the hot water supply burner 21 and the opening degree of the bypass servo 55 so that the hot water supply temperature detected by the hot water supply temperature sensor 57 becomes the hot water supply set temperature. When the water amount sensor 52 no longer detects water flow, the supply of the combustion gas to the hot water supply burner 21 is cut off and the combustion of the hot water supply burner 21 is stopped.

  The amount of combustion of hot water supply burner 21 is controlled by which one or a plurality of burners among burner A, burner B, and burner C are burned, and the opening of gas proportional valve 42.

  FIG. 3 shows the relationship between the combustion amount of the hot water supply burner 21 and the opening degree of the gas proportional valve 42. In the range where the required combustion amount is F1 or less, the first hot water supply gas electromagnetic valve 43 and the third hot water supply gas electromagnetic valve 45 are closed, the second hot water supply gas electromagnetic valve 44 is opened, and only the burner B is burned. The amount of combustion inside is adjusted by the opening degree of the gas proportional valve 42.

  In the range where the required combustion amount exceeds F1 and is equal to or less than F2, the third hot water gas electromagnetic valve 45 is closed, the first hot water gas electromagnetic valve 43 and the second hot water gas electromagnetic valve 44 are opened, and the burners A and B are burned. The combustion amount within the above range is adjusted by the opening degree of the gas proportional valve 42.

  In the range where the required combustion amount exceeds F2, the first hot water supply gas electromagnetic valve 43, the second hot water supply gas electromagnetic valve 44, and the third hot water supply gas electromagnetic valve 45 are all opened to burn the burners A, B, C. The amount of combustion within the range is adjusted by the opening of the gas proportional valve 42.

<Pouring operation>
The pouring operation is executed when an automatic bath operation or pouring instruction is received from the remote controller. In the pouring operation, the control unit opens the pouring electromagnetic valve 67 and ignites the hot water supply burner 21 to burn the combustion gas in the hot water supply burner 21. Thus, the water supply from the water supply source is heated by receiving the heat of the exhaust from the hot water supply burner 21 when passing through the hot water supply latent heat exchanger 22b and the hot water sensible heat exchanger 22a. After being mixed with the water supply, it flows into the bath return pipe 60 through the connecting pipe 66 and is poured into the bathtub 2 through the bath return pipe 60 and the bath outlet pipe 61.

  When the bathtub 2 reaches a set water level, the pouring operation is stopped. Specifically, the hot water solenoid valve 67 is closed and the supply of the combustion gas to the hot water supply burner 21 is shut off to stop the combustion of the hot water supply burner 21.

<Bath chasing action>
The bath reheating operation is performed when the temperature of the bath water in the bathtub 2 is raised to the bath set temperature after the above-described pouring operation is performed based on the instruction for automatic bath operation and the water is filled to the set water level. Alternatively, it is executed when the temperature of the hot water in the bathtub 2 is raised during the automatic operation of the bath to maintain the bath set temperature, or when a follow-up instruction is received from the user.

  In the bath reheating operation, the control unit turns on the circulation pump 62 and ignites the bath burner 31 to burn the combustion gas in the bath burner 31. The bath water in the bathtub 2 is taken into the bath return pipe 60 by the action of the circulation pump 62, and the bath return pipe 60, the bath latent heat exchanger 32 b, the bath sensible heat exchanger 32 a, and the bath outlet pipe 61. It circulates so that it may return to bathtub 2 via. The bath water is heated by receiving the heat of the exhaust from the bath burner 31 when passing through the bath latent heat exchanger 32b and the bath sensible heat exchanger 32a.

<Simultaneous use of hot water supply and bath chasing>
The simultaneous use of hot water supply and bath reheating occurs, for example, when a hot water tap is opened and hot water is supplied during a bath reheating operation. In simultaneous use of hot water supply and bath reheating, the opening degree of the gas proportional valve 42 is controlled based on the hot water supply operation (prioritizing the hot water supply side). That is, the opening degree of the gas proportional valve 42 is controlled in accordance with the characteristics of FIG. 3 and the like so that the hot water supply burner 21 burns with a combustion amount necessary to supply hot water at the hot water supply set temperature.

  At this time, when the opening of the gas proportional valve 42 is small and the temperature of the bath water returning from the bathtub 2 is low, the bath heat exchanger 32 (particularly, the sensible heat exchanger 32a for bath) There is a possibility that the temperature does not rise so much and moisture in the combustion exhaust is condensed in the bath sensible heat exchanger 32a.

  Therefore, the bath water heater 10 according to the present embodiment determines whether or not there is a possibility of condensation in the bath sensible heat exchanger 32a when the hot water supply side and the bath side are burned simultaneously. When it determines with possibility, the control which interrupts the combustion of the bath burner 31 is performed.

  In this determination, the amount of heat transferred from the hot water supply heat exchanger 22 side to the bath heat exchanger 32 through the fins 25 and the like described in FIG. 2 is taken into consideration. That is, the amount of heat transmitted from the hot water supply heat exchanger 22 side to the bath heat exchanger 32 is further added to the temperature detected by the bath return temperature sensor 64 and the combustion amount of the bath burner 31, and dew condensation occurs in the hot water supply latent heat exchanger 22b. It is determined whether or not to do.

  Specifically, the presence or absence of condensation is determined based on the detected temperature of the bath return temperature sensor 64, the combustion amount of the bath burner 31, and the combustion amount of the hot water supply burner 21.

  Here, as shown in FIG. 3, since the opening degree of the gas proportional valve 42 with respect to the combustion amount of the hot water supply burner 21 is uniquely determined, if the combustion amount of the hot water supply burner 21 is determined, the hot water supply burner 21 and the gas proportional valve 42 are set. The amount of combustion of the commonly used bath burner 31 is also determined. Therefore, determining the presence or absence of dew condensation based on the temperature detected by the bath return temperature sensor 64 and the amount of combustion of the hot water supply burner 21 is based on the temperature detected by the bath return temperature sensor 64, the amount of combustion of the bath burner 31, and the hot water supply burner 21. This is equivalent to determining the presence or absence of condensation based on the amount of combustion.

  Here, as shown in FIG. 4, data indicating the relationship between the temperature detected by the bath return temperature sensor 64 (bath return temperature), the combustion amount of the hot water supply burner 21 (hot water supply side combustion amount), and the presence or absence of condensation is used. The temperature and the combustion amount on the hot water supply side are determined in advance, and the detected temperature of the bath return temperature sensor 64 (bath return temperature) and the combustion amount of the hot water supply burner 21 (hot water supply side combustion amount) are determined from the data. A lookup table (correlation data) is created in which the input value is used and the possibility of condensation is output.

  Then, the current detection temperature of the bath return temperature sensor 64 and the combustion amount of the hot water supply burner 21 set by the control unit are input to the lookup table, and the presence or absence of condensation is determined from the output value.

  Note that which burner A, B, or C is burned with respect to the amount of combustion of the hot water supply burner 21 is determined in advance, so which burner is uniquely determined from the amount of combustion of the hot water supply burner 21. . Therefore, the correlation data takes into account which burner is burning.

  For example, as shown in FIG. 3, only burner B is initially controlled. When the combustion amount exceeds F1, burner B and A, and when F2 is exceeded, control is performed as A + B + C. When F1 is exceeded, the contents of the correlation data are different between the burners B and C, and when F2 is exceeded, control is performed as A + B + C. If the burn amount of the hot water supply burner 21 does not uniquely correspond to which burner is burned, what burner is burned may be added to the determination element for the presence or absence of condensation as another parameter.

  Moreover, although the air volume of the combustion fan 11 is changed according to the combustion amount of the hot water supply burner 21, the air volume with respect to each combustion amount of the hot water supply burner 21 is also uniquely determined. Therefore, if the combustion amount of the hot water supply burner 21 is used as a parameter, the air volume of the combustion fan 11 is also taken into consideration in the determination of the possibility of condensation. When the combustion amount of the hot water supply burner 21 and the air volume of the combustion fan 11 are not uniquely determined, the air volume of the combustion fan 11 may be added to the determination element as another parameter.

  FIG. 5 is a flowchart showing a combustion control process performed by the control unit of the bath water heater 10. This process is executed when there is a combustion request from either the hot water supply side or the bath side. It is checked whether or not there is a request for simultaneous combustion (step S101). If there is no request for simultaneous combustion (step S101; No), single combustion on the request side (the aforementioned hot water supply operation, pouring operation, bath reheating operation) 1), and the process proceeds to step S107.

  When there is a simultaneous combustion request (step S101; Yes), the correlation data of FIG. 4 is input with the detected temperature (bath return temperature) of the bath return temperature sensor 64 and the combustion amount of the hot water supply burner 21 (hot water supply side combustion amount) as input values. The determination result of the presence or absence of condensation is acquired from (step S103).

  When the determination result indicates that there is no possibility of condensation (step S104; No), the hot water supply burner 21 and the bath burner 31 are simultaneously burned (step S105), and the process proceeds to step S107.

  If the determination result obtained in step S102 indicates the possibility of condensation (step S104; Yes), the bath gas electromagnetic valve 46 is shut off to turn off the combustion of the bath burner 31, and only the hot water supply burner 21 side is burned. (Step S106), the process proceeds to Step S107.

  In step S107, it is checked whether or not all combustion requests are turned off. If there is a combustion request on either the hot water supply side or the bath retreat side (step S107; No), the process returns to step S101 and the processing is continued. . If all the combustion requests are off (step S107; Yes), this process is terminated.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to that shown in the embodiment, and there are changes and additions within the scope of the present invention. Are also included in the present invention.

  In the embodiment, the hot water supply burner 21 and the bath burner 31 are exemplified as the types having a latent heat exchanger and a sensible heat exchanger, but the present invention is also applied to a sensible heat exchanger alone.

  In the embodiment, the temperature detected by the bath return temperature sensor 64 is used as a material for determining the presence or absence of dew condensation. However, the sensible heat exchange for the bath is performed after leaving the bath latent heat exchanger 32b of the bath heat exchanger 32. A temperature sensor that detects the temperature of the bath water before entering the vessel 32a may be provided, and the temperature detected by the temperature sensor may be used as the determination material.

  In the embodiment, the presence or absence of dew condensation is determined using the correlation data in the look-up table format. However, if a function corresponding to the correlation data can be defined, the bath return temperature and the hot water side combustion amount are input to the function. The presence or absence of condensation may be determined from the calculation result of the function.

DESCRIPTION OF SYMBOLS 2 ... Bathtub 3 ... Bathtub water intake 4 ... Bathtub water discharge port 10 ... Bath water heater 11 ... Combustion fan 12 ... Exhaust port 13 ... Combustion chamber 14 ... Partition plate 15 ... Drain receptacle 16 ... Collection pipe 17 ... Neutralizer 21 ... Hot-water supply burner (Burner A, B, C)
22 ... Heat exchanger for hot water supply 22a ... Sensible heat exchanger for hot water supply 22b ... Latent heat exchanger for hot water supply 24 ... Heat receiving pipe 25 ... Fin 31 ... Bath burner 32 ... Heat exchanger for bath 32a ... Sensible heat exchange for bath 32b ... Bath latent heat exchanger 40 ... Gas supply pipe 41 ... Original gas solenoid valve 42 ... Gas proportional valve 43 ... First hot water gas solenoid valve 44 ... Second hot water gas solenoid valve 45 ... Third hot water gas solenoid valve 46 ... Bath gas solenoid valve 50 ... Water supply pipe 51 ... Hot water supply pipe 52 ... Water quantity sensor 53 ... Water quantity servo 54 ... Bypass pipe 55 ... Bypass servo 56 ... Heat exchange temperature sensor 57 ... Hot water temperature sensor 60 ... Bath return pipe 61 ... Bath return pipe 62 ... Circulating pump 63 ... Flowing water switch 64 ... Bath return temperature sensor 65 ... Bathing temperature sensor 66 ... Connecting pipe 67 ... Pouring solenoid valve 68 ... Check valve

Claims (6)

A heat exchanger for hot water supply,
A hot water supply burner for heating the hot water supply heat exchanger;
A heat exchanger for bathing, which is thermally connected to the heat exchanger for hot water supply,
A bath burner for heating the bath-heating heat exchanger;
A proportional valve for adjusting the amount of gas supplied to the hot-water supply burner and the bath burner;
A first shutoff valve for switching whether to supply gas to the hot water burner;
A second shut-off valve for switching whether to supply gas to the bath burner;
A temperature sensor for detecting a temperature of water entering the heat exchanger for bathing,
A circulation pump that circulates the bath water via the heat exchanger for bathing when bathing,
A controller for controlling the combustion of the hot water burner and the bath burner,
The controller controls the opening of the proportional valve with priority given to the hot water supply side when performing hot water supply and bath reheating at the same time, and further adds the hot water supply to the detected temperature of the temperature sensor and the combustion amount of the bath burner. In consideration of the amount of heat transmitted from the heat exchanger side to the bath-heating heat exchanger, it is determined whether or not condensation occurs in the bath-heating heat exchanger. A bath water heater characterized by performing dew condensation prevention control that shuts off gas supply to the bath burner by means of a valve. 2. The bath water heater according to claim 1, wherein the controller determines the presence or absence of the dew condensation based on a temperature detected by the temperature sensor, a combustion amount of the bath burner, and a combustion amount of the hot water supply burner. . The bath water heater according to claim 1, wherein the control unit determines the presence or absence of the dew condensation based on a temperature detected by the temperature sensor and a combustion amount of the hot water supply burner. The hot water burner is composed of a plurality of sub-burners,
The first shut-off valve can select the number and location of sub-burners that cut off the supply of combustion gas among the sub-burners,
The controller controls the combustion amount of the entire hot water burner by switching the opening of the proportional valve and the number and location of the sub burners that block the supply of combustion gas in the hot water burner,
The bath water heater according to claim 2 or 3, wherein in the determination of the presence or absence of dew condensation, the sub-burner that is burning is taken into account. The bath water heater according to any one of claims 1 to 4, wherein the bath-heating heat exchanger is a latent heat recovery type heat exchanger that recovers latent heat and sensible heat. 6. The bath water heater according to claim 5, wherein the temperature sensor detects a temperature of water entering the sensible heat recovery unit of the heat exchanger for reheating the bath.