Hot water supply heater

Abstract

To more accurately estimate a residual water amount in a bathtub without using a sensor for directly detecting the residual water amount in the bathtub even when a heating medium is supplied from a heating circuit to a heat radiation terminal in a hot water supply heater.SOLUTION: A hot water supply heater 1 includes: a bath circulation pump 55 for causing hot water in a bath circulation passage 63 to flow; a first temperature sensor 64 for detecting a temperature on an outlet side of a liquid-liquid heat exchanger in the bath circulation passage 63; and a second temperature sensor 65 for detecting a temperature on the inlet side of the liquid-liquid heat exchanger in the bath circulation passage 63. A residual water amount estimation section estimates a residual water amount in a bathtub 52 on the basis of rotational frequency of the bath circulation pump 55 detected by a rotational frequency detection section, the inlet side temperature detected by the first temperature sensor 64 and the outlet side temperature detected by the second temperature sensor 65 at least when a heating medium is being supplied from a heating circuit 3 to a heat radiation terminal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a water heater with a heating function.

Background Art

[0002] Patent Document 1 describes a combined heat source machine. This combined heat source machine includes a hot water supply circuit, a heating circuit, a supplementary heating circuit, and a controller. The heating circuit includes an expansion tank, a heat exchanger for heating, and a circulation pump for heating, which are connected by pipes. The hot water in the expansion tank is sent to the downstream heat exchanger for heating by the circulation pump for heating and is heated here. The downstream side of the heat exchanger for heating branches into a first high-temperature bypass path on the supplementary heating circuit side and a second high-temperature bypass path on the high-temperature water supply port side, and the hot water passing through these is configured to return to the expansion tank.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the field of water heaters equipped with a bathtub circuit, a method of estimating the remaining amount of water in the bathtub without using a device that directly detects the remaining amount of water in the bathtub has been considered. As an example, for instance, a method of calculating the remaining amount of water in the bathtub based on the amount of heat supplied to the gas burner and the rate of temperature rise in the bathtub circuit is used.

[0005] However, in a water heater with a heating function equipped with a heating circuit that supplies a heat medium to a heating terminal as in Patent Document 1, since the proportion of the amount of heat supplied to the gas burner that is reflected in the "supply of heat medium to the heating terminal" is large, when using a method of calculating the remaining amount of water in the bathtub based on the amount of heat supplied to the gas burner, there is a problem that the error becomes large.

[0006] One of the objects of the present disclosure is to provide a technique that can more accurately estimate the remaining amount of water in a bathtub without using a sensor that directly detects the remaining amount of water in the bathtub even when the heat medium is supplied from the heating circuit to the heat dissipation terminal in the water heater.

Means for Solving the Problems

[0007] A water heater which is one of the present disclosures is a first burner that burns gas, and a first heat exchanger that is heated by the exhaust gas generated by the combustion of the gas in the first burner, and a hot water supply circuit that heats the water supplied from the outside by the first heat exchanger to supply hot water, a second burner that burns gas, a second heat exchanger that is heated by the exhaust gas generated by the combustion of the gas in the second burner, and a heat medium circulation path that is a path for circulating the heat medium so as to pass through the second heat exchanger, and heats the heat medium by the second heat exchanger, and a heating circuit that supplies the heat medium to the heat dissipation terminal through the heat medium circulation path, a branch path that branches from the heat medium circulation path and guides the heat medium that has flowed through the heat medium circulation path, a bathtub circuit having a bathtub circulation path that circulates the hot water derived from the bathtub and introduces it into the bathtub, a bathtub heat exchanger that performs heat exchange between the heat medium flowing through the branch path and the hot water flowing through the bathtub circulation path, a pump having a rotating drive unit that causes the hot water in the bathtub circulation path to flow, a first temperature sensor that detects the temperature on the outlet side of the bathtub heat exchanger in the bathtub circulation path, a second temperature sensor that detects the temperature on the inlet side of the bathtub heat exchanger in the bathtub circulation path, a rotation speed detection unit that detects the rotation speed of the drive unit in the pump, a remaining amount estimation unit that estimates the remaining amount of water in the bathtub, and has The remaining water amount estimation unit estimates the amount of remaining water in the bathtub based on the rotation speed detected by the rotation speed detection unit, the inlet side temperature detected by the first temperature sensor, and the outlet side temperature detected by the second temperature sensor, at least when the heat medium is supplied from the heating circuit to the heat dissipation terminal. Effect of the Invention

[0008] The technology disclosed herein can more accurately estimate the amount of water remaining in a bathtub without using a sensor that directly detects the amount of water remaining in the bathtub, even when a heat transfer medium is supplied from the heating circuit to the heat dissipation terminal in a hot water heater / heating unit. [Brief description of the drawings]

[0009]

Figure 1

[0010] The following technology is an example of a hot water heater included in the present disclosure.

[0011] [1] A hot water supply circuit including a first burner for burning gas and a first heat exchanger heated by exhaust gas generated by burning the gas in the first burner, and for supplying hot water by heating water supplied from the outside using the first heat exchanger; a heating circuit including a second burner for burning gas, a second heat exchanger heated by exhaust gas generated by burning the gas in the second burner, and a heat medium circulation path that is a path for circulating a heat medium through the second heat exchanger, the heating circuit heating the heat medium by the second heat exchanger and supplying the heat medium to a heat dissipation terminal via the heat medium circulation path; A branch path that branches off from the heat medium circulation path and guides the heat medium that has flowed through the heat medium circulation path; A bath circuit having a bath circulation path that circulates hot and cold water drawn out from a bathtub and introduces it into the bathtub; A bath heat exchanger that performs heat exchange between the heat medium flowing through the branch path and the hot water flowing through the bath circulation path, A pump having a rotating drive unit that causes the hot water in the bath circulation path to flow, A first temperature sensor that detects the temperature on the outlet side of the bath heat exchanger in the bath circulation path, A second temperature sensor that detects the temperature on the inlet side of the bath heat exchanger in the bath circulation path, A rotation speed detection unit that detects the rotation speed of the drive unit in the pump, A remaining water amount estimation unit that estimates the remaining water amount in the bathtub, having The remaining water amount estimation unit estimates the remaining water amount in the bathtub based on at least the rotation speed detected by the rotation speed detection unit, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor when the heat medium is being supplied from the heating circuit to the heat dissipation terminal. A hot water supply and heating machine.

[0012] The hot water supply and heating machine according to [1] above can measure the remaining water amount in the bathtub without using a sensor that directly detects the remaining water amount in the bathtub. Further, this hot water supply and heating machine can estimate the remaining water amount in the bathtub based on the rotation speed detected by the rotation speed detection unit, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor. Therefore, even when the heat medium is being supplied from the heating circuit to the heat dissipation terminal in the hot water supply and heating machine, the supply of the heat medium to the heat dissipation terminal is less likely to have a significant impact on the accuracy of the remaining water amount estimation, and the remaining water amount in the bathtub can be measured more accurately.

[0013] 〔2〕 The remaining water amount estimation unit estimates the remaining water amount in the bathtub based on at least the rotation speed detected by the rotation speed detection unit, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor when the rotation speed detected by the rotation speed detection unit is within the allowable rotation speed range when the heat medium is being supplied from the heating circuit to the heat dissipation terminal. The hot water supply and heating machine according to [1].

[0014] On the premise that the rotational speed is within the allowable rotational speed range, the hot water supply and heating machine of [2] estimates the remaining water volume in the bathtub based on the rotational speed detected by the rotational speed detection unit, so it is easy to suppress a decrease in estimation accuracy caused by the rotational speed greatly deviating from the allowable rotational speed range.

[0015] 〔3〕 It has a storage unit that stores information specifying the correspondence between each rotational speed of the pump and the flow rate of the hot water flowing through the pump. The rotational speed detection unit detects the rotational speed of the pump based on the value of the current supplied to the drive unit when the pump is driven. When the rotational speed detected by the rotational speed detection unit is within the allowable rotational speed range, at least when the heat medium is supplied from the heating circuit to the heat dissipation terminal, the remaining water volume in the bathtub is estimated based on the flow rate specified based on the rotational speed detected by the rotational speed detection unit and the information stored in the storage unit, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor. The hot water supply and heating machine according to [1].

[0016] On the premise that the rotational speed is within the allowable rotational speed range, the hot water supply and heating machine of [3] estimates the remaining water volume in the bathtub based on the flow rate specified by the rotational speed detected by the rotational speed detection unit, so it is easy to suppress a decrease in estimation accuracy caused by the rotational speed greatly deviating from the allowable rotational speed range, and the remaining water volume in the bathtub can be measured more accurately based on a more accurate flow rate. Furthermore, since the rotational speed detection unit detects the rotational speed of the pump based on the value of the current supplied to the drive unit when the pump is driven, not only the configuration related to the sensor that directly detects the remaining water volume in the bathtub but also the configuration related to the sensor that directly detects the rotational speed of the pump can be easily simplified.

[0017] 〔4〕When the rotation speed detected by the rotation speed detection unit does not fall within the allowable rotation speed range, at least when the heat medium is being supplied from the heating circuit to the heat dissipation terminal, the remaining water amount estimation unit stops the supply of the heat medium to the heat dissipation terminal in the heating circuit, and based on the amount of gas supplied to the second burner, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor, in a state where the supply of the heat medium to the heat dissipation terminal is stopped, estimates the remaining water amount in the bathtub. The hot water supply and heating machine according to any one of 〔1〕 to 〔3〕.

[0018] When the rotation speed detected by the rotation speed detection unit of the hot water supply and heating machine of 〔4〕 above does not fall within the allowable rotation speed range, it is possible to estimate the remaining water amount in the bathtub based on the amount of gas supplied to the second burner without taking the rotation speed information as a main factor. For example, when clogging occurs in the bathtub or the bath circulation path, etc., it cannot be rotated at a desired rotation speed and deviates from the allowable rotation speed range. If the remaining water amount estimation method using the rotation speed as it is is adopted, there is a concern that the estimation accuracy of the remaining water amount will decrease. However, when the rotation speed is outside the allowable rotation speed range, the above hot water supply and heating machine estimates the remaining water amount in the bathtub based on the amount of gas supplied to the second burner, so it is easy to suppress the decrease in estimation accuracy caused by the rotation speed deviating greatly from the allowable rotation speed range. Moreover, this hot water supply and heating machine estimates the remaining water amount in the bathtub based on the amount of gas supplied to the second burner in a state where the supply of the heat medium to the heat dissipation terminal in the heating circuit is stopped. That is, this hot water supply and heating machine can measure the remaining hot water amount more accurately based on the amount of gas supplied to the second burner in a state where the ratio of the heat amount of combustion of the gas supplied to the second burner reflected in the temperature rise in the bathtub is increased.

[0019] <First Embodiment> The following description relates to the hot water supply and heating machine 1 according to the first embodiment. 1. Overall configuration of the hot water supply and heating machine 1 FIG. 1 is a schematic circuit diagram of the water heater 1. The water heater 1 mainly includes a hot water supply circuit 2, a heating circuit 3, a bathtub circuit 4, etc., and is a device that can perform hot water supply operations, automatic water filling operations, afterburning operations, heating operations, etc.

[0020] The water heater 1 is provided with a housing 1A configured as a metal casing inside the housing, and a first combustion system part 5 and a second combustion system part 6 are configured inside the housing 1A. The housing 1A is configured as, for example, a metal can body or a metal box body, and houses a hot water supply burner 8A as an example of a first burner, a heating burner 33A as an example of a second burner, a hot water supply side heat exchanger 7 as an example of a first heat exchanger, a heating side heat exchanger 32 as an example of a second heat exchanger, etc. The first combustion system part 5 is a combustion system that performs gas combustion and water heating when the hot water supply circuit 2 performs a hot water supply operation. The second combustion system part 6 is a combustion system that performs gas combustion and water heating during heating operations or afterburning operations.

[0021] The hot water supply circuit 2 is a circuit that heats water supplied from outside the water heater 1 by the hot water supply side heat exchanger 7 and supplies hot water. The hot water supply circuit 2 includes the first combustion system part 5, and specifically includes a plurality of hot water supply burners 8A and the hot water supply side heat exchanger 7. An ignition plug 85 and a flame sensor 86 are provided above the hot water supply burner 8A. The ignition plug 85 ignites the combustion gas by generating a spark discharge in response to an input signal from the control device 70, and the flame generated by the combustion is detected by the flame sensor 86. A hot water supply combustion chamber 5A is provided in the first combustion system part 5, and a hot water supply side burner unit 8 and the hot water supply side heat exchanger 7 are provided in the hot water supply combustion chamber 5A. The hot water supply side burner unit 8 includes burner blocks 9A, 9B, 9C, and each of the burner blocks 9A, 9B, 9C includes a plurality of hot water supply burners 8A. Each of the plurality of hot water supply burners 8A is configured as a gas burner that burns gas.

[0022] The hot water supply side heat exchanger 7 is a heat exchanger heated by the exhaust gas generated by the hot water supply burner 8A. The hot water supply side heat exchanger 7 includes a first hot water supply side heat exchanger 7A and a second hot water supply side heat exchanger 7B. The first hot water supply side heat exchanger 7A has a plurality of fins 7Z. The first combustion system section 5 is provided with the first hot water supply side heat exchanger 7A above a plurality of hot water supply burners 8A, and the second hot water supply side heat exchanger 7B is provided above the first hot water supply side heat exchanger 7A. A pipeline 7C is connected between the downstream end of the second hot water supply side heat exchanger 7B and the upstream end of the first hot water supply side heat exchanger 7A, and the hot water flowing through the second hot water supply side heat exchanger 7B flows through the pipeline 7C to the first hot water supply side heat exchanger 7A. The hot water supply side heat exchanger 7 heats the water passing through the inside by the exhaust gas (combustion exhaust gas) generated by burning gas with a plurality of hot water supply burners 8A. The first hot water supply side heat exchanger 7A recovers sensible heat from the combustion exhaust gas discharged from the hot water supply side burner unit 8, and the second hot water supply side heat exchanger 7B recovers latent heat from the combustion exhaust gas discharged from the hot water supply side burner unit 8.

[0023] The hot water supply circuit 2 further includes a water supply pipe 11, a water supply control valve 13A, a water flow sensor 14, a hot water outlet pipe 10, a bypass pipe 12, a bypass control valve 13B, a thermistor 15A (hot water supply inner cylinder thermistor), a thermistor 15B (hot water supply and outlet thermistor), etc. The water supply pipe 11 is connected to the inlet of the hot water supply side heat exchanger 7. The water supply pipe 11 is connected to an external pipe, and is configured as a pipeline that introduces tap water from, for example, a water supply and flows this tap water toward the upstream end (inlet) of the hot water supply side heat exchanger 7. The water flow sensor 14 is a sensor that detects the flow rate of the water flowing through the water supply pipe 11. The water supply control valve 13A is a valve for controlling the flow rate of the water flowing through the water supply pipe 11, and is a valve that changes the opening degree of the water supply pipe 11 by control. The hot water outlet pipe 10 is connected to the downstream end (outlet) of the hot water supply side heat exchanger 7. The hot water outlet pipe 10 is a pipeline that flows the hot water heated by the hot water supply side heat exchanger 7. The hot water outlet pipe 10 forms a path for discharging the hot water heated by the hot water supply side heat exchanger 7 outside the appliance.

[0024] A bypass pipe 12 is connected between the water supply pipe 11 and the hot water outlet pipe 10 so as to bypass the hot water side heat exchanger 7. A bypass control valve 13B (bypass control valve) is provided in the bypass pipe 12. The bypass control valve 13B is a valve for controlling the flow rate of water flowing through the bypass pipe 12. Specifically, it is configured as a valve that changes the opening degree of the bypass pipe 12 by control. A thermistor 15A is provided upstream of the connection portion of the bypass pipe 12 in the hot water outlet pipe 10. The thermistor 15A detects the temperature of the hot water discharged from the hot water side heat exchanger 7. Specifically, it detects the hot water temperature near the outlet of the first heat exchanger 7A on the hot water supply side. A thermistor 15B is provided downstream of the connection portion of the bypass pipe 12. The thermistor 15B detects the hot water temperature after mixing of the water from the bypass pipe 12. Specifically, it detects the temperature of the hot water supplied downstream of the confluence point of the bypass pipe 12 in the hot water outlet pipe 10. The temperatures of the hot water detected by these thermistors 15A and 15B are input to a control device 70 described later.

[0025] The hot water supply circuit 2 further includes a gas pipe 16, a main gas solenoid valve 17, a gas proportional valve 18, and a solenoid valve 19. The gas pipe 16 is a pipe through which gas supplied from outside the hot water supply and heating machine 1 via a gas inlet passes, and forms a path for supplying gas to the hot water supply burner 8A. A main gas solenoid valve 17 is provided upstream of the gas pipe 16, and a gas proportional valve 18 is provided downstream of the main gas solenoid valve 17. The downstream side of the gas proportional valve 18 (hot water supply gas proportional valve) in the gas pipe 16 branches, and branch pipes 16A to each of the burner blocks 9A, 9B, 9C and branch pipes 16B to each of the burner blocks 34A, 34B are provided. A solenoid valve 19 is provided in each branch pipe 16A. The solenoid valve 19 (hot water supply switching solenoid valve) switches the branch pipe 16A between an open state (supply possible state) and a closed state (shut-off state), and the supply and shut-off of fuel gas to each of the burner blocks 9A, 9B, 9C are individually switched by each solenoid valve 19. By switching the solenoid valve 19, the combustion range of the hot water supply side burner unit 8 is switched, and each combustion range is associated as a stage number.

[0026] The hot water supply circuit 2 further includes a fan 20. The fan 20 has a rotating body 20B that generates wind by its rotation and a drive source 20A that rotates the rotating body 20B. The fan 20 is provided below the hot water supply combustion chamber 5A. By the operation of the fan 20, combustion air is supplied to each hot water supply burner 8A and the heating burner 33A, and the combustion exhaust gas discharged from the hot water supply side burner unit 8 and the heating side burner unit 33 is discharged from the exhaust port 90. Near the fan 20, a current sensor 75 that detects the drive current of the fan 20 and a rotation speed sensor 76 that detects the rotation speed (rotational speed) of the fan 20 are provided. A signal corresponding to the drive current of the fan 20 detected by the current sensor 75 and a signal corresponding to the rotation speed of the fan 20 detected by the rotation speed sensor 76 are output to the control device 70. The hot water supply circuit 2 is also provided with an igniter for ignition, an ignition electrode, a hot water supply flame rod, and the like.

[0027] The bath circuit 4 includes a bath circulation path 63 and a bath heat exchanger 50. The bath circulation path 63 forms a flow path configured to circulate the hot water derived from the bathtub 52, which is an external bathtub provided outside the hot water supply and heating machine 1, and introduce it into the bathtub 52. The bath heat exchanger 50 is configured as a liquid-liquid heat exchanger that performs heat exchange between the heat medium flowing through the bath heating branch path 51 and the hot water flowing through the bath circulation path 63.

[0028] The bathtub heat exchanger 50 includes a pipe 50A that forms part of the bathtub circulation path 63, and is configured such that the bathtub heating branch path 51 is disposed within the pipe 50A. The bathtub circulation path 63 includes the pipe 50A, the bathtub supply pipe 53, and the bathtub return pipe 54. When the bathtub circulation pump 55 operates, the bathtub circulation path 63 functions as a flow path for drawing out hot water from the bathtub 52 provided outside the hot water supply and heating unit 1, and functions as a flow path for circulating the drawn-out hot water and introducing it into the bathtub 52. The bathtub return pipe 54 is provided with a bathtub circulation pump 55 for flowing the hot water in the bathtub return pipe 54 in a predetermined direction, and a water flow switch 57 for detecting that hot water with a predetermined flow rate or more is flowing through the bathtub return pipe 54. The bathtub return pipe 54 is provided between the bathtub 52 outside the appliance and the pipe 50A, and forms a flow path for flowing hot water from the bathtub 52 to the pipe 50A when the bathtub circulation pump 55 operates. The bathtub supply pipe 53 is provided between the pipe 50A and the bathtub 52, and forms a flow path for flowing hot water from the pipe 50A to the bathtub 52 when the bathtub circulation pump 55 operates. The bathtub supply pipe 53 is provided with a first temperature sensor 64 as a bathtub supply thermistor for detecting the temperature of the hot water flowing out from the bathtub heat exchanger 50 to the bathtub 52. The bathtub return pipe 54 is provided with a second temperature sensor 65 as a bathtub return thermistor for detecting the temperature of the hot water flowing into the bathtub return pipe 54 from the bathtub 52. The first temperature sensor 64 is a sensor for detecting the temperature on the outlet side of the bathtub heat exchanger 50 in the bathtub circulation path 63. The second temperature sensor 65 is a sensor for detecting the temperature on the inlet side of the bathtub heat exchanger 50 in the bathtub circulation path 63.

[0029] A drop pipe 59 is connected to the bathtub return pipe 54 in a configuration branched from the hot water discharge pipe 10. The drop pipe 59 communicates with the bathtub return pipe 54. The drop pipe 59 is provided with a hot water supply solenoid valve 60, a drop water volume sensor 61, a plurality of check valves 62, and the like. When the hot water supply solenoid valve 60 provided in the drop pipe 59 is opened during the operation of the hot water supply circuit 2, the hot water heated by the hot water supply circuit 2 is supplied to the bathtub 52 through the drop pipe 59.

[0030] The heating circuit 3 is a circuit that can heat the heat medium by means of the heating-side heat exchanger 32 and supply the heat medium to the heat dissipation terminal (heating terminal) via the heat medium circulation path 48. In the present embodiment, the heat medium is, for example, hot water. Note that, as the heat medium, a fluid other than hot water may be used. The heating circuit 3 includes the second combustion system unit 6 and the heat medium circulation path 48. The second combustion system unit 6 is provided with a heating combustion chamber 6A, and a heating-side burner unit 33 and a heating-side heat exchanger 32 are provided in the heating combustion chamber 6A. The heating combustion chamber 6A is partitioned by a partitioning member 80 from the hot water supply combustion chamber 5A in the housing 1A, and a temperature sensor 82 for detecting the temperature of the heating combustion chamber 6A is provided on the partitioning member 80.

[0031] The heating-side burner unit 33 includes burner blocks 34A and 34B, and each of the burner blocks 34A and 34B includes a plurality of heating burners 33A. Each of the plurality of heating burners 33A is configured as a gas burner that burns gas. An ignition plug 85 and a flame sensor 86 are provided above the heating burner 33A.

[0032] The heating-side heat exchanger 32 is a heat exchanger heated by the exhaust gas generated by the heating burner 33A. Specifically, it is a device that acts to heat the heat medium passing through its interior by the combustion exhaust gas of the heating burner 33A. The heating-side heat exchanger 32 includes a heating-side first heat exchanger 32A and a heating-side second heat exchanger 32B. The heating-side first heat exchanger 32A has a plurality of fins 32Z. The second combustion system unit 6 has the heating-side first heat exchanger 32A provided above a plurality of heating burners 33A, and the heating-side second heat exchanger 32B provided above the heating-side first heat exchanger 32A. The heating-side heat exchanger 32 heats the heat medium passing through its interior by the exhaust gas (combustion exhaust gas) generated by burning gas with a plurality of heating burners 33A. The heating-side first heat exchanger 32A is supplied with the exhaust gas (combustion exhaust gas) generated by burning gas with the heating burner 33A (gas burner), and functions to heat the heat medium passing through the heating-side first heat exchanger 32A by the heat of this combustion exhaust gas. The heating-side first heat exchanger 32A recovers sensible heat from the combustion exhaust gas discharged from the heating-side burner unit 33. The heating-side second heat exchanger 32B is supplied with the gas after the combustion exhaust gas has passed through the heating-side first heat exchanger 32A, and functions to heat the heat medium passing through the heating-side second heat exchanger 32B by this gas. The heating-side second heat exchanger 32B recovers latent heat from the combustion exhaust gas discharged from the heating-side burner unit 33.

[0033] The heat medium circulation path 48 is a path for circulating the heat medium so as to pass through the heating-side heat exchanger 32, forming the flow path of the heat medium. The heat medium circulation path 48 includes a common forward flow path 38K as a heating forward pipe, a first internal flow path 38A as a heating high-temperature forward pipe, a second internal flow path 38B as a heating low-temperature forward pipe, and a common flow path 38C as a heating return pipe.

[0034] When the first heat dissipation terminal 39A as a heating terminal is connected as shown in FIG. 1, the heat medium circulation path 48 is configured such that the heat medium circulates through the common flow path 38K, the first internal flow path 38A, the first terminal flow path 38G of the first heat dissipation terminal 39A, and the common flow path 38C. When the second heat dissipation terminal 39Z as a heating terminal is connected as shown in FIG. 1, the heat medium circulation path 48 is configured such that the heat medium circulates through the common flow path 38K, the second internal flow path 38B, the second terminal flow path 38H of the second heat dissipation terminal 39Z, and the common flow path 38C.

[0035] The first internal flow path 38A is connected to the first heat dissipation terminal 39A as a flow path so as to communicate with the first terminal flow path 38G provided outside the hot water heater 1. The first internal flow path 38A is configured as a flow path branched from the branch portion 38J, and is configured as a flow path for flowing the heat medium from the branch portion 38J to the first heat dissipation terminal 39A. A part of the first internal flow path 38A is provided in the first heat exchanger 32A on the heating side, and the heat medium flowing through the first internal flow path 38A is configured to be heated in the first heat exchanger 32A on the heating side.

[0036] The second internal flow path 38B is connected to the second heat dissipation terminal 39Z as a flow path so as to communicate with the second terminal flow path 38H provided outside the hot water heater 1. The second internal flow path 38B is configured as a flow path branched from the branch portion 38J, and is configured as a flow path for flowing the heat medium from the branch portion 38J to the second heat dissipation terminal 39Z.

[0037] The heating circuit 3 further includes an expansion tank 36, a heating circulation pump 37, a heating high-temperature thermistor 40, and a heating low-temperature thermistor 41. The common flow path 38C is a flow path through which the heat medium flowing into the inflow portion 35A returns to the expansion tank 36. In the example of FIG. 1, the upstream end of the common flow path 38C is the inflow portion 35A, and the downstream end of the common flow path 38C is connected to the inlet portion 36C of the expansion tank 36. The common flow path 38C is configured as a pipe that introduces the heat medium exiting from the first heat dissipation terminal 39A and the heat medium exiting from the second heat dissipation terminal 39Z into the interior through the inflow portion 35A and causes it to flow through the heating-side heat exchanger 32 (heating-side second heat exchanger 32B). The common flow path 38C is configured to communicate with the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and is connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z as a flow path for flowing the heat medium.

[0038] An intermediate pipe 38D and an intermediate pipe 38E are provided between the outlet of the heating-side second heat exchanger 32B and the inlet of the heating-side first heat exchanger 32A. In the paths of the intermediate pipes 38D and 38E, the expansion tank 36 and the heating circulation pump 37 are provided, and the heat medium can flow from the heating-side second heat exchanger 32B to the heating-side first heat exchanger 32A through the intermediate pipe 38D, the expansion tank 36, and the intermediate pipe 38E. The intermediate pipe 38D is a part of the common flow path 38C and is a flow path between the outlet of the heating-side second heat exchanger 32B and the inlet portion 36C of the expansion tank 36. The intermediate pipe 38E is a pipe formed by a part of the common flow path 38K and the first internal flow path 38A, and is provided between the outlet portion 36B of the expansion tank 36 and the inlet of the heating-side first heat exchanger 32A.

[0039] The common flow path 38K is configured as a flow path that introduces the heat medium flowing out from the outlet portion 36B and flows the heat medium flowing out from the expansion tank 36. A heating circulation pump 37 is provided in the middle of the common flow path 38K. The heating circulation pump 37 causes the heat medium in the common flow path 38K to flow from the expansion tank 36 side to the branch portion 38J side.

[0040] The second internal flow path 38B is provided with a configuration in which a plurality of internal branch paths 38F branch off. A second valve 39G is provided in each internal branch path 38F as a valve for opening and closing each branch path 39F. In the example of FIG. 1, one internal branch path 38F communicates with the second heat radiation terminal 39Z and is connected to the second heat radiation terminal 39Z outside the appliance. The downstream sides of the first heat radiation terminal 39A and the second heat radiation terminal 39Z communicate with a common flow path 38C. The first heat radiation terminal 39A is, for example, a high-temperature heating terminal such as a heating blower that blows warm air into a bathroom or a dressing room. The second heat radiation terminal 39Z is, for example, a low-temperature heating terminal such as floor heating in a dressing room.

[0041] The heating high-temperature thermistor 40 is provided in the first internal flow path 38A on the outlet side of the heating-side heat exchanger 32, and detects the temperature of the heat medium flowing out from the heating-side heat exchanger 32 (specifically, the heat medium flowing out from the first heat exchanger 32A on the heating side). The temperature detected by the heating high-temperature thermistor 40 corresponds to the temperature of the heat medium flowing into the first heat radiation terminal 39A during the circulation of the heat medium passing through the first heat radiation terminal 39A. The heating low-temperature thermistor 41 is provided in the expansion tank 36. The temperature detected by the heating low-temperature thermistor 41 corresponds to the temperature of the heat medium flowing into the second heat radiation terminal 39Z during the circulation of the heat medium passing through the second heat radiation terminal 39Z.

[0042] The heating circuit 3 includes a plurality of branch pipes 16B and a plurality of heating switching solenoid valves 44. As described above, the branch pipe 16B is provided with a configuration branched from the gas pipe 16 to the heating circuit 3 side. Each heating switching solenoid valve 44 is provided in each branch pipe 16B. The heating switching solenoid valve 44 is configured to switch the branch pipe 16B in which it is provided between an open state (supply possible state) and a closed state (cut-off state). The supply and cut-off of the fuel gas to each of the burner blocks 34A, 34B are individually switched by each heating switching solenoid valve 44. By switching the heating switching solenoid valve 44, the combustion range of the heating-side burner unit 33 is switched, and each combustion range is associated as a number of steps. Note that the heating circuit 3 is also provided with an ignition electrode, a heating frame rod, and the like.

[0043] In the heating circuit 3, due to the operation of the heating circulation pump 37, the hot water heated by the heating-side heat exchanger 32 circulates through the heat medium circulation path 48. Specifically, in the heating circuit 3, when the heating circulation pump 37 operates, the hot water flowing through the heat medium circulation path 48 is heated by the combustion exhaust gas discharged from the heating-side burner unit 33 in the heating-side heat exchanger 32, and circulates through the common flow path 38C, the first internal flow path 38A, and the first heat dissipation terminal 39A, and at the same time, circulates through the common flow path 38C, the second internal flow path 38B, and the second heat dissipation terminal 39Z. In the example of FIG. 1, hot water is supplied to the first heat dissipation terminal 39A according to the operation of the first valve 39H which is a built-in thermostatic valve. The second heat dissipation terminal 39Z is configured as a low-temperature heating terminal, and hot water is supplied to the second heat dissipation terminal 39Z according to the operation of the second valve 39G which is a thermostatic valve in the appliance.

[0044] As shown in FIG. 1, a branch path 51 for bath heating is provided in a configuration branched from the first internal flow path 38A. The branch path 51 for bath heating branches from a position on the downstream side of the heating-side heat exchanger 32 in the heat medium circulation path 48 (specifically, on the downstream side of the heating-side first heat exchanger 32A), and forms a flow path for guiding the heat medium flowing through the heat medium circulation path 48 to the bath heat exchanger 50 side. The branch path 51 for bath heating is connected between the first internal flow path 38A and the common flow path 38C so as to communicate with each other. A control valve 58 is provided on the upstream side of the bath heat exchanger 50 in the branch path 51 for bath heating. The control valve 58 is configured to open and close the branch path 51 for bath heating, and is configured to switch between a closed state in which the water flow passing through itself in the branch path 51 for bath heating is blocked, and an open state in which the water flow passing through itself in the branch path 51 for bath heating is allowed.

[0045] The hot water supply and heating machine 1 further includes a control device 70, a hot water supply remote controller 71, a bath remote controller 72, a heating remote controller 73, and a room temperature thermistor (not shown). The control device 70 is an electronic control device including an information processing device such as a CPU, a memory such as a semiconductor memory device, an interface circuit, etc., and functions as a controller for performing various controls. Various programs, data tables, set values, etc. are stored in the above memory. The control device 70 is configured to be able to acquire signals from various sensors and switches (thermistors, water volume sensors, switches, etc.), and controls a hot water supply circuit 2, a heating circuit 3, a bath circuit 4, etc. The above room temperature thermistor is provided, for example, in the dressing room as a temperature detection means for detecting the temperature in the dressing room. Note that the control device 70 may be constituted by a single device (for example, a controller configured as a single unit), or may be constituted by a plurality of devices.

[0046] 2. Basic operation of the hot water supply and heating machine 1 (Normal hot water supply operation) When a hot water supply faucet provided outside the device to communicate with the hot water outlet pipe 10 is opened and water flows into the appliance, and the water volume sensor 14 outputs a signal indicating water flow, the control device 70 rotates the fan 20 for a predetermined time to discharge the combustion exhaust gas stored in the hot water supply combustion chamber 5A (purging). Thereafter, the control device 70 opens the main gas solenoid valve 17 of the gas pipe 16 and each solenoid valve 19, and opens the gas proportional valve 18 at a predetermined opening degree, and controls to supply gas to each hot water supply burner 8A, and operates the igniter to ignite the hot water supply burner 8A. When gas is burned by the hot water supply burner 8A by such control, the water passing through the hot water supply side heat exchanger 7 by the combustion exhaust gas generated by the combustion is heated and a hot water outlet operation is performed so as to flow to the hot water outlet pipe 10, and the heated hot water is discharged from the above hot water supply faucet.

[0047] During the above hot water supply operation, the control device 70 monitors the hot water temperature detected by the thermistor 15B provided in the hot water supply pipe 10, and controls the opening and closing of the solenoid valve 19 and adjusts the opening degree of the gas proportional valve 18 so that the hot water temperature becomes the set temperature indicated by the hot water supply remote controller 71 or the bath remote controller 72. At the same time, the air volume is continuously changed by controlling the rotation speed of the fan 20. When the hot water supply faucet is closed during the above hot water supply operation and the signal output by the water volume sensor 14 indicates a water flow stop state, the control device 70 closes the original gas solenoid valve 17 and the solenoid valve 19 to extinguish the hot water supply burner 8A, and rotates the fan 20 for a predetermined time to perform post-purge.

[0048] (Automatic hot water filling operation) The control device 70 can perform control to automatically fill the bathtub 52 with hot water. For example, when the hot water filling switch provided on the hot water supply remote controller 71 or the bath remote controller 72 is pressed, the control device 70 sets the hot water temperature to the hot water filling temperature set by the hot water supply remote controller 71 or the bath remote controller 72 as the target temperature (for example, 40 ° C) and starts hot water filling. Specifically, the control device 70 opens the hot water supply solenoid valve 60 of the drop pipe 59 to put the hot water supply circuit 2 into a water flow state, and burns the hot water supply burner 8A so that the heated hot water flows into the hot water supply pipe 10. The hot water flowing through the hot water supply pipe 10 in this way is supplied to the bathtub 52 through the drop pipe 59 and the bath return pipe 54.

[0049] After the control device 70 starts supplying hot water to the bathtub 52 in this way, it monitors whether the water volume detected by the drop water volume sensor 61 provided in the drop pipe 59 (total water volume since the start of automatic hot water filling) has reached the set water volume. When it is confirmed that the water volume has reached the set water volume, the control device 70 closes the hot water supply solenoid valve 60 to stop the water flow, extinguishes the hot water supply burner 8A, and ends the hot water filling. After that, the control device 70 operates the bath circulation pump 55 to circulate the hot water in the bathtub 52 in the bath circuit 4. When the control device 70 finishes the hot water filling, it notifies the hot water supply remote controller 71 or the bath remote controller 72 of the end of the hot water filling.

[0050] (Automatic reheating operation) The control device 70 can perform control to automatically reheat (boil up) the water stored in the bathtub 52. For example, when the reheat switch provided on the hot water supply remote control 71 or the bath remote control 72 is pressed, the control device 70 sets the reheat temperature to the target temperature (e.g., 40 °C) set on the hot water supply remote control 71 or the bath remote control 72 and starts the reheat. Specifically, the control device 70 ignites the heating burner 33A, opens the control valve 58, operates the bath circulation pump 55, and performs reheat by heating with the bath heat exchanger 50 while circulating the hot water in the bathtub 52. After starting such reheat, the control device 70 monitors whether the hot water temperature detected by the temperature sensor 65 has reached the target temperature. When it is confirmed that the temperature has reached, the control device 70 extinguishes the heating burner 33A, stops the bath circulation pump 55, and ends the reheat. When the control device 70 ends the reheat, it notifies the hot water supply remote control 71 or the bath remote control 72 of the end of the reheat.

[0051] 3. Configuration for Heating Operation The hot water supply and heating machine 1 constitutes a hot water supply system while being connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and supplies the heat medium that has been branched and flowed through the internal flow path to the external first heat dissipation terminal 39A and the second heat dissipation terminal 39Z.

[0052] As shown in FIG. 1, the downstream end of the common flow path 38K in the heat medium circulation path 48 is a branch portion 38J. The branch portion 38J is a portion that branches the flow of the heat medium flowing through the common flow path 38K. The upstream side of the branch portion 38J is the common flow path 38K, and the downstream side of the branch portion 38J branches into a first internal flow path 38A and a second internal flow path 38B. The first internal flow path 38A has a reheat branch portion 56 that branches into the bath circuit 4. On the bath circuit 4 side branched at the reheat branch portion 56, the bath heating branch path 51 passes through the bath heat exchanger 50 and is connected to the common flow path 38C. The lower side (downstream side) of the reheat branch portion 56 has a connection portion 46B that branches into the bypass flow path 46.

[0053] The bypass flow path 46 is provided between the common flow path 38C and the first internal flow path 38A. The bypass flow path 46 is a path through which the heat medium can flow so as to bypass between the common flow path 38C and the first internal flow path 38A.

[0054] The downstream end of the first internal flow path 38A is configured to be connectable to the outside and is a first outflow portion 35B through which the heat medium flows out. The first outflow portion 35B is provided at the downstream end of the first internal flow path 38A and is configured as an outlet for flowing out the heat medium from the first internal flow path 38A toward the first terminal flow path 38G. The downstream end of the second internal flow path 38B is configured to be connectable to the outside and is a second outflow portion 35C through which the heat medium flows out. The second outflow portion 35C is provided at the downstream end of the second internal flow path 38B and is configured as an outlet for flowing out the heat medium from the second internal flow path 38B toward the second terminal flow path 38H. The upstream end of the common flow path 38C is configured to be connectable to the outside and is an inflow portion 35A through which the heat medium flows in. The inflow portion 35A is provided on the downstream side of the first terminal flow path 38G and on the downstream side of the second terminal flow path 38H, and is an inlet through which the heat medium flowing through the first terminal flow path 38G flows in, and is also an inlet through which the heat medium flowing through the second terminal flow path 38H flows in.

[0055] Outside the water heater 1, a first heat radiation terminal 39A and a second heat radiation terminal 39Z are provided, to which the heat medium is supplied from the water heater 1 and which communicate with the heat medium circulation path 48. The first heat radiation terminal 39A has a first terminal flow path 38G through which the heat medium flows, and radiates the heat of the heat medium flowing through the first terminal flow path 38G. In the space near the first heat radiation terminal 39A, the air is heated by the heat of the heat medium flowing through the first terminal flow path 38G being radiated. The first heat radiation terminal 39A is configured as a high-temperature heating terminal. The second heat radiation terminal 39Z has a second terminal flow path 38H through which the heat medium flows, and radiates the heat of the heat medium flowing through the second terminal flow path 38H. In the space near the second heat radiation terminal 39Z, the air is heated by the heat of the heat medium flowing through the second terminal flow path 38H being radiated. The downstream end of the first terminal flow path 38G and the downstream end of the second terminal flow path 38H are configured to be connectable so as to communicate with the inflow portion 35A of the water heater 1.

[0056] The supply of the heat medium to the first terminal flow path 38G is switched between a state of blocking the supply of the heat medium and a state of permitting it by opening and closing the first valve 39H. When the first valve 39H is open, it is permitted for the heat medium to pass through the first valve 39H, and it is permitted for the heat medium to flow from the inside of the first internal flow path 38A, through the first terminal flow path 38G, to the downstream side (the inflow portion 35A side) of the first valve 39H. When the first valve 39H is closed, it is blocked for the heat medium to pass through the first valve 39H, and no heat medium flows from the inside of the first internal flow path 38A to the downstream side of the first valve 39H. The supply of the heat medium to the second terminal flow path 38H is switched between a state of blocking the supply of the heat medium and a state of permitting it by opening and closing the second valve 39G. When the second valve 39G is open, it is permitted for the heat medium to pass through the second valve 39G, and it is permitted for the heat medium to flow from the inside of the second internal flow path 38B, through the second terminal flow path 38H, to the downstream side (the inflow portion 35A side) of the second valve 39G. When the second valve 39G is closed, it is blocked for the heat medium to pass through the second valve 39G, and no heat medium flows from the inside of the second internal flow path 38B to the downstream side of the second valve 39G. Both the first valve 39H and the second valve 39G are thermostatic valves. The thermostatic valve, for example, expands an expansion body with the heat of a heating element (Positive Temperature Coefficient) when the power is turned on, pushes a piston to open the valve so that hot and cold water can flow, and when the power is turned off, the heating element naturally dissipates heat to contract the expansion body and close the valve.

[0057] The heat medium flowing into the inflow portion 35A circulates in the heat medium circulation path 48 in the water heater 1. Specifically, the heat medium flows downstream from the inflow portion 35A through the common flow path 38C, is heated by the heating-side second heat exchanger 32B, then passes through the expansion tank 36, and is further moved downstream by the power of the heating circulation pump 37. Then, the heat medium flowing toward the branch portion 38J is divided at the branch portion 38J into the heat medium flowing toward the first internal flow path 38A and the heat medium flowing toward the second internal flow path 38B. The heat medium flowing through the first internal flow path 38A is heated by the heating-side first heat exchanger 32A on the way.

[0058] The heat medium flowing through the first internal flow path 38A flows out toward the first terminal flow path 38G with the first outflow portion 35B as the outlet. The heat medium flowing through the second internal flow path 38B flows out as the heat medium toward the second terminal flow path 38H with the second outflow portion 35C as the outlet.

[0059] The first valve 39H that opens and closes the first terminal flow path 38G, the second valve 39G that opens and closes the second internal flow path 38B, and the heating circulation pump 37 are controlled by the control device 70. The control device 70 is electrically connected to each of the first valve 39H, the second valve 39G, and the heating circulation pump 37, and performs opening and closing control of the first valve 39H and the second valve 39G and driving control of the heating circulation pump 37.

[0060] 4. Configuration for estimating the remaining amount of water in the bathtub 52 (Outline of estimation) In the present embodiment, the control device 70 corresponds to an example of a remaining amount estimation unit and functions to estimate the remaining amount of water in the bathtub 52. As described above, the bath circuit 4 is provided with a bath circulation pump 55 that circulates the hot water in the bath circulation path 63, a first temperature sensor 64 that detects the temperature on the outlet side of the liquid-liquid heat exchanger in the bath circulation path 63, and a second temperature sensor 65 that detects the temperature on the inlet side of the liquid-liquid heat exchanger in the bath circulation path 63. The bath circulation pump 55 corresponds to an example of a pump and has a rotating drive unit, and is configured such that the flow rate of the hot water flowing through the bath circulation pump 55 (the amount of hot water flowing through the bath circulation pump 55 per unit time) increases as the rotation speed of the drive unit increases.

[0061] In such a configuration, the control device 70 corresponds to an example of a rotation speed detection unit and functions to detect the rotation speed of the drive unit in the bath circulation pump 55. Specifically, the control device 70 detects the rotation speed of the bath circulation pump 55 based on the value of the current supplied to the drive unit when the bath circulation pump 55 is driven. In the present embodiment, the drive unit of the bath circulation pump 55 is configured as a motor, and the greater the current applied to the drive unit (motor), the greater the rotation speed of the drive unit (motor). The correspondence between the current applied to the drive unit (motor) and the rotation speed of the drive unit (motor) is specified by information such as a predetermined arithmetic expression or table, and this information is stored in a storage unit provided in the control device 70 or the like. The control device 70 includes a known drive circuit for driving the drive unit (motor) of the bath circulation pump 55 and can grasp the current applied to the drive unit (motor). Therefore, the control device 70 can continuously monitor the current applied to the drive unit (motor) and can specify the rotation speed of the drive unit (motor) based on the above information.

[0062] The control device 70 that functions as a remaining water amount estimation unit estimates the remaining water amount in the bathtub 52 based on at least the rotation speed of the bath circulation pump 55 detected by itself (the control device 70 which is a rotation speed detection unit), the temperature on the inlet side detected by the first temperature sensor 64, and the temperature on the outlet side detected by the second temperature sensor 65 when the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal.

[0063] The case where "the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal" means a state in which the heating circuit 3 performs the above-described heating operation, circulates the heat medium in the heat medium circulation path 48, and supplies the heat medium to any heat dissipation terminal. The following representative example relates to an example of estimating the remaining hot water amount in the bathtub 52 when the heating operation of supplying the heat medium from the heating circuit 3 to the heat dissipation terminal is performed and the bath circulation pump 55 is driven to aim for the target rotation speed by the driving of the bath circulation pump 55 accompanying the automatic hot water filling operation.

[0064] (When the rotation speed is within the allowable rotation speed range) When a predetermined condition is satisfied (for example, when the execution start condition of automatic hot water filling is satisfied), the control device 70 performs a process of estimating the remaining water volume in the bathtub 52. For example, when the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal and the execution start condition of automatic hot water filling is satisfied, the rotation speed of the bathtub circulation pump 55 is controlled to a predetermined target rotation speed. In a state where the control device 70 is attempting to control the rotation speed of the bathtub circulation pump 55 to the predetermined target rotation speed in this way, the control device 70 determines whether the rotation speed of the bathtub circulation pump 55 is within the allowable rotation speed range (a range of not less than the lower limit value Nmin and not more than the upper limit value Nmax). When the rotation speed is within the allowable rotation speed range, the control device 70 estimates the remaining water volume in the bathtub 52 based on the rotation speed of the bathtub circulation pump 55, the temperature on the inlet side detected by the first temperature sensor 64, and the temperature on the outlet side detected by the second temperature sensor 65.

[0065] Specifically, in a storage unit provided in the control device 70 or the like, first information for specifying the correspondence between each rotation speed of the bathtub circulation pump 55 and the flow rate of the hot water flowing through the bathtub circulation pump 55 is stored. The first information may be stored in advance, or the flow rate for each rotation speed may be detected during the operation of the hot water supply and heating device 1, and the correspondence may be calculated and then the first information may be stored. The first information is information determined such that as the rotation speed of the bathtub circulation pump 55 increases, the flow rate corresponding to the rotation speed (the flow rate of the hot water flowing through the bathtub circulation pump 55) increases. The first information may be an arithmetic expression for calculating the flow rate of the hot water flowing through the bathtub circulation pump 55 with the rotation speed of the bathtub circulation pump 55 as a variable, or may be a table or the like that defines the value of the flow rate of the hot water flowing through the bathtub circulation pump 55 in association with each rotation speed of the bathtub circulation pump 55. The control device 70 specifies the rotation speed of the bathtub circulation pump 55 based on the current supplied to the drive unit (motor) of the bathtub circulation pump 55, and specifies the flow rate (the flow rate of the hot water flowing through the bathtub circulation pump 55) at the specified rotation speed based on the first information.

[0066] The control device 70 estimates the remaining amount of water in the bathtub 52 based on the flow rate in the case of the detected rotational speed, the temperature on the inlet side detected by the first temperature sensor 64, and the temperature on the outlet side detected by the second temperature sensor 65. Specifically, in a storage unit provided in the control device 70 or the like, second information such as an arithmetic expression or a table for specifying the remaining amount of hot water in the bathtub 52 is prepared based on "the flow rate of the hot water flowing through the bath circulation pump 55" and "the difference between the temperature on the inlet side and the temperature on the outlet side". This second information is an arithmetic expression or a table such that when the flow rate of the hot water flowing through the bath circulation pump 55 is the same, the smaller the difference between the temperature on the inlet side and the temperature on the outlet side, the smaller the remaining amount of hot water. Also, the second information is an arithmetic expression or a table such that when the difference between the temperature on the inlet side and the temperature on the outlet side is the same, the larger the flow rate of the hot water flowing through the bath circulation pump 55, the smaller the remaining amount of hot water. In this way, the control device 70 can specify the remaining amount of water in the bathtub 52 according to the second information based on the flow rate in the case of the detected rotational speed, the temperature on the inlet side detected by the first temperature sensor 64, and the temperature on the outlet side detected by the second temperature sensor 65.

[0067] (When the rotational speed is not within the allowable rotational speed range) For example, when the automatic hot water filling start condition is satisfied while the heat medium is being supplied from the heating circuit 3 to the heat dissipation terminal, the control device 70 attempts to control the rotational speed of the bath circulation pump 55 to a predetermined target rotational speed. However, when the rotational speed of the bath circulation pump 55 is not within the allowable rotational speed range, the control device 70 stops the supply of the heat medium to the heat dissipation terminal in the heating circuit 3. Examples of the operation of stopping the supply of the heat medium to the heat dissipation terminal include an operation of stopping the heating circulation pump 37. The control device 70 estimates the remaining amount of water in the bathtub 52 based on the amount of gas supplied to the heating burner 33A (second burner), the temperature on the inlet side detected by the first temperature sensor 64, and the temperature on the outlet side detected by the second temperature sensor 65 in a state where the supply of the heat medium to the heat dissipation terminal in the heating circuit 3 is stopped in this way.

[0068] Specifically, in a storage unit provided in a control device 70 or the like, third information such as an arithmetic expression or a table for specifying the remaining hot water amount in the bathtub 52 is prepared based on "the amount of gas supplied to the heating burner 33A (second burner)" and "the difference between the inlet-side temperature and the outlet-side temperature". This third information is an arithmetic expression or a table such that, if the amount of gas supplied to the heating burner 33A (second burner) is the same, the smaller the difference between the inlet-side temperature and the outlet-side temperature, the smaller the remaining hot water amount. When using an arithmetic expression, an arithmetic expression for calculating the amount of heat based on the above gas amount and the thermal efficiency of the heating-side heat exchanger 32, and calculating the remaining hot water amount based on this amount of heat and the above degree of increase (the difference between the inlet-side temperature and the outlet-side temperature) can be adopted. Further, the third information is an arithmetic expression or a table such that, if the difference between the inlet-side temperature and the outlet-side temperature is the same, the larger the amount of gas supplied to the heating burner 33A (second burner), the larger the remaining hot water amount. Thus, the control device 70 can specify the remaining water amount in the bathtub 52 according to the third information based on the amount of gas supplied to the heating burner 33A (second burner), the inlet-side temperature detected by the first temperature sensor 64, and the outlet-side temperature detected by the second temperature sensor 65.

[0069] 5. Examples of effects The water heater 1 can estimate the remaining water amount in the bathtub 52 without using a sensor that directly detects the remaining water amount in the bathtub 52. Further, since this water heater 1 can estimate the remaining water amount in the bathtub 52 based on the rotation speed detected by the rotation speed detection unit, the inlet-side temperature detected by the first temperature sensor 64, and the outlet-side temperature detected by the second temperature sensor 65, even when the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal in the water heater 1, the supply of the heat medium to the heat dissipation terminal is less likely to have a great influence on the accuracy of the estimation of the remaining water amount, and the remaining water amount in the bathtub 52 can be measured more accurately.

[0070] The water heater 1 estimates the remaining water amount in the bathtub 52 based on the rotation speed detected by the rotation speed detection unit on the premise that the rotation speed is within the allowable rotation speed range. Therefore, it is easy to suppress a decrease in estimation accuracy caused by the rotation speed greatly deviating from the allowable rotation speed range.

[0071] Assuming that the rotational speed of the water heater 1 is within the allowable rotational speed range, in order to estimate the remaining water volume in the bathtub 52 based on the flow rate specified by the rotational speed detected by the rotational speed detection unit, it is easy to suppress a decrease in estimation accuracy caused by the rotational speed greatly deviating from the allowable rotational speed range, and the remaining water volume in the bathtub 52 can be measured more accurately based on a more accurate flow rate. Further, since the rotational speed detection unit detects the rotational speed of the bath circulation pump 55 based on the value of the current supplied to the drive unit when the bath circulation pump 55 is driven, not only the configuration related to the sensor that directly detects the remaining water volume of the bathtub 52 but also the configuration related to the sensor that directly detects the rotational speed of the bath circulation pump 55 can be easily simplified.

[0072] When the rotational speed detected by the rotational speed detection unit of the water heater 1 is not within the allowable rotational speed range, the remaining water volume in the bathtub 52 can be estimated based on the amount of gas supplied to the heating burner 33A (second burner) without using the rotational speed information as a main element. Therefore, this water heater 1 can easily suppress a decrease in estimation accuracy caused by the rotational speed greatly deviating from the allowable rotational speed range. Moreover, this water heater 1 estimates the remaining water volume in the bathtub 52 based on the amount of gas supplied to the heating burner 33A (second burner) in a state where the supply of the heat medium to the heat dissipation terminal in the heating circuit 3 is stopped. That is, this water heater 1 can measure the remaining hot water volume more accurately based on the amount of gas supplied to the heating burner 33A (second burner) in a state where the ratio of the heat quantity of the combustion of the gas supplied to the heating burner 33A (second burner) reflected in the temperature rise in the bathtub 52 is increased.

[0073] <Other Embodiments> The present invention is not limited to the embodiments described by the above description and drawings. For example, the features of the above-described or below-described embodiments can be combined in any combination within a non-contradictory range. Also, any feature of the above-described or below-described embodiments can be omitted if it is not explicitly specified as essential. Further, the above-described embodiments may be modified as follows.

[0074] In the above-described embodiment, the control device corresponds to an example of the rotation speed detection unit, but a rotation speed sensor different from the control device may be provided.

[0075] In the above-described embodiment, when the automatic hot water filling operation is started and the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal, the remaining water amount in the bathtub 52 is estimated by the above-described method. However, when the supplementary heating operation is started and the heat medium is supplied from the heating circuit 3 to the heat dissipation terminal, the remaining water amount in the bathtub 52 may be estimated by the above-described method.

[0076] It should be considered that all aspects of the embodiments disclosed this time are illustrative and not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, and it is intended that all modifications within the scope indicated by the claims or within the scope equivalent to the claims are included.

Explanation of Reference Numerals

[0077] 1: Water heater 2: Hot water supply circuit 3: Heating circuit 4: Bathtub circuit 7: Hot water supply side heat exchanger (first heat exchanger) 7A: First hot water supply side heat exchanger 7B: Second hot water supply side heat exchanger 8: Hot water supply side burner unit 8A: Hot water supply burner (first burner) 32: Heating side heat exchanger (second heat exchanger) 32A: First heating side heat exchanger 32B: Second heating side heat exchanger 33: Heating side burner unit 33A: Heating burner (second burner) 39A: First heat dissipation terminal (heat dissipation terminal) 39Z: Second heat dissipation terminal (heat dissipation terminal) 48: Heat medium circulation path 50: Bathtub heat exchanger 50A: Pipeline 51: Branch path for bathtub heating (branch path) 52: Bathtub 55: Bathtub circulation pump (pump) 63: Bathtub circulation path 64: First temperature sensor 65: Second temperature sensor 65: Temperature sensor 70: Control device (rotation speed detection unit, remaining water volume estimation unit)

Claims

1. A first burner for burning gas, and a first heat exchanger heated by the exhaust gas generated by the combustion of the gas in the first burner, and a hot water supply circuit for heating the water supplied from the outside by the first heat exchanger to supply hot water. A second burner for burning gas, a second heat exchanger heated by the exhaust gas generated by the combustion of the gas in the second burner, and a heat medium circulation path which is a path for circulating the heat medium so as to pass through the second heat exchanger. A heating circuit for heating the heat medium by the second heat exchanger and supplying the heat medium to the heat dissipation terminal via the heat medium circulation path. A branch path branched from the heat medium circulation path for guiding the heat medium flowing through the heat medium circulation path. A bathtub circuit having a bathtub circulation path for circulating the hot water derived from the bathtub and introducing it into the bathtub. A bathtub heat exchanger for performing heat exchange between the heat medium flowing through the branch path and the hot water flowing through the bathtub circulation path. A pump having a rotating drive unit for flowing the hot water in the bathtub circulation path. A first temperature sensor for detecting the temperature on the outlet side of the bathtub heat exchanger in the bathtub circulation path. A second temperature sensor for detecting the temperature on the inlet side of the bathtub heat exchanger in the bathtub circulation path. A rotation speed detection unit for detecting the rotation speed of the drive unit in the pump. A remaining water amount estimation unit for estimating the remaining water amount in the bathtub. And having When the heat medium is supplied from at least the heating circuit to the heat dissipation terminal, the remaining water amount estimation unit is based on the rotation speed detected by the rotation speed detection unit, the temperature on the inlet side detected by the first temperature sensor, and the second temperature sensor. The remaining water amount in the bathtub is estimated based on the detected outlet temperature. A hot water supply and heating machine.

2. When the rotation speed detected by the rotation speed detection unit is within the allowable rotation speed range at least when the heat medium is supplied from the heating circuit to the heat dissipation terminal, the remaining water amount estimation unit is based on the rotation speed detected by the rotation speed detection unit, the temperature on the inlet side detected by the first temperature sensor, and the second temperature sensor. The remaining water amount in the bathtub is estimated based on the detected outlet temperature. The hot water supply and heating machine according to claim 1.

3. Having a storage unit for storing information specifying the correspondence relationship between each rotation speed of the pump and the flow rate of the hot water flowing through the pump. The rotation speed detection unit detects the rotation speed of the pump based on the value of the current supplied to the drive unit when the pump is driven. When the rotation speed detected by the rotation speed detection unit is within the allowable rotation speed range, at least when the heat medium is being supplied from the heating circuit to the heat dissipation terminal, the remaining water amount estimation unit estimates the remaining water amount in the bathtub based on the flow rate in the case of the rotation speed specified based on the rotation speed detected by the rotation speed detection unit and the information stored in the storage unit, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor. The water heater according to claim 1.

4. When the rotation speed detected by the rotation speed detection unit is not within the allowable rotation speed range, at least when the heat medium is being supplied from the heating circuit to the heat dissipation terminal, the remaining water amount estimation unit stops the supply of the heat medium to the heat dissipation terminal in the heating circuit, and estimates the remaining water amount in the bathtub based on the amount of gas supplied to the second burner in the state where the supply of the heat medium to the heat dissipation terminal is stopped, the temperature on the inlet side detected by the first temperature sensor, and the temperature on the outlet side detected by the second temperature sensor. The water heater according to claim 2 or claim 3.

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