Hot water supply heater

Abstract

To inhibit dew condensation from being formed around a second heat exchanger due to decrease in the temperature of combustion exhaust generated by a second burner.SOLUTION: A hot water supply heater 1 includes: a storage body 1A for storing a heating circuit 3, etc.; a fan 20 for supplying air in the storage body 1A; a partition member 80 for partitioning the storage body 1A; temperature sensors 40 and 41 for detecting the temperature of a heat medium circulation passage 48; and a control device 70 for performing control so that a heating circulation pump 37 is driven at a rotation speed RN0 in the state that the supply of the heating medium to terminal flow channels 38G and 38H is permitted by selector valves 39H and 39G. When the temperature detected by the temperature sensors 40 and 41 is equal to or lower than a predetermined threshold TH, the control device 70 performs a dew condensation suppression operation for reducing the rotation speed of the heating circulation pump 37 from the rotation speed RN0.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a water heater and heater.

Background Art

[0002] Patent Document 1 describes a water heating and heating heat source machine. This water heating and heating heat source machine includes a water heating burner that heats water supplied from a water supply pipe in a combustion chamber that forms a common outer shell inside a can body, and a heating burner that heats the hot water in the hot water flow path on the heating side. At the lower part of the combustion chamber, an air supply and exhaust fan is provided in common to supply combustion air for the water heating burner and the heating burner into the combustion chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, this type of water heating and heating heat source machine is required to accurately discharge hot water at a temperature set by a remote controller from the water supply pipe on the hot water supply side. On the other hand, on the heating side (such as floor heating), generally, an accurate temperature as high as that on the hot water supply side is not necessarily required, and heating can be achieved by circulating a heat medium to an external heating terminal. Therefore, in the case of simultaneous operation in which both the water heating side burner and the heating side burner accommodated in a common combustion chamber are simultaneously burned and controlled as in Patent Document 1 above, higher-precision control is required for the water heating side circuit than for the heating side circuit. Therefore, it is conceivable to perform combustion control centering on the water heating side circuit.

[0005] However, when combustion control is performed with the hot water supply side circuit as the center during simultaneous operation, the rotational speed of the fan may decrease according to the required combustion amount on the hot water supply side, and the combustion amount of the heating burner may decrease. In this case, if the temperature of the hot water circulating in the heating side circuit is low, the temperature of the combustion exhaust gas around the heat exchanger in the heating side circuit may be excessively lowered, and condensation may occur around the heat exchanger in the heating side circuit.

[0006] One of the objectives of the present disclosure is to provide a technology for suppressing the occurrence of condensation around the heating side heat exchanger due to a decrease in the temperature of the combustion exhaust generated by the heating side burner in a hot water heater in which the hot water supply side burner and the heating side burner are housed in a common housing.

Means for Solving the Problem

[0007] A hot water heater which is one of the present disclosures is a hot water heater that has a terminal flow path through which a heat medium flows, supplies the heat medium to a heat dissipation terminal that dissipates the heat of the heat medium flowing through the terminal flow path, and controls a switching valve that switches between a state of blocking and a state of permitting the supply of the heat medium to the terminal flow path, comprising a first burner that burns gas, and a first heat exchanger that is heated by the exhaust generated by the first burner, and a hot water supply circuit that heats water supplied from the outside by the first heat exchanger to supply hot water, comprising a second burner that burns gas, a second heat exchanger that is heated by the exhaust generated by the second burner, a path that circulates the heat medium together with the terminal flow path, a heat medium circulation path that passes through the second heat exchanger, and a pump that causes the heat medium to flow in the heat medium circulation path, heating the heat medium by the second heat exchanger, and supplying the heat medium to the terminal flow path via the heat medium circulation path, a heating circuit, a housing that houses the first burner, the second burner, the first heat exchanger, and the second heat exchanger, a partition member that partitions the inside of the housing into a hot water supply combustion chamber that houses the first burner and the first heat exchanger and a heating combustion chamber that houses the second burner and the second heat exchanger, a fan that supplies air into the housing, A combustion control unit that controls the combustion of the first burner and the second burner and controls the rotation speed of the fan, A temperature sensor that detects the temperature of the heat medium circulation path, A pump control unit that performs normal operation to rotationally drive the pump in a state where the supply of the heat medium to the terminal flow path is permitted by the switching valve, and includes, When performing the hot water supply only operation in which the first burner is burned without burning the second burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner. When performing the heating only operation in which the second burner is burned without burning the first burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the second burner. When performing the simultaneous operation in which the first burner and the second burner are burned, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner. When the temperature detected by the temperature sensor is equal to or lower than a threshold value, at least during the simultaneous operation, the pump control unit performs a dew condensation suppression operation of driving the pump at a rotation speed lower than the rotation speed corresponding to the combustion region and gas supply amount of the first burner.

Advantages of the Invention

[0008] In the hot water supply and heating apparatus in which the burner on the hot water supply side and the burner on the heating side are housed in a common housing, the technology according to the present disclosure can suppress the occurrence of dew condensation around the heat exchanger on the heating side due to a temperature drop of the combustion exhaust generated by the burner on the heating side.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiment for Carrying Out the Invention

[0010] Each of the following [1] to [4] is an example of the technology included in the present disclosure.

[0011] [1] A hot water heater that supplies a heat medium to a heat dissipation terminal having a terminal flow path through which the heat medium flows and that dissipates the heat of the heat medium flowing through the terminal flow path, and controls a switching valve that switches between a state of blocking the supply of the heat medium to the terminal flow path and a state of permitting it, comprising a first burner that burns gas, and a first heat exchanger that is heated by the exhaust gas generated by the first burner, and a hot water supply circuit that heats 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 second burner, a path that circulates the heat medium together with the terminal flow path, a heat medium circulation path that passes through the second heat exchanger, and a pump that causes the heat medium to flow in the heat medium circulation path, and a heating circuit that heats the heat medium by the second heat exchanger and supplies the heat medium to the terminal flow path via the heat medium circulation path, a housing that houses the first burner, the second burner, the first heat exchanger, and the second heat exchanger, a partition member that partitions the inside of the housing into a hot water supply combustion chamber that houses the first burner and the first heat exchanger and a heating combustion chamber that houses the second burner and the second heat exchanger, a fan that supplies air into the housing, a combustion control unit that controls the combustion of the first burner and the second burner and controls the rotational speed of the fan, a temperature sensor that detects the temperature of the heat medium circulation path, a pump control unit that performs normal operation so as to rotationally drive the pump in a state where the supply of the heat medium to the terminal flow path is permitted by the switching valve, and comprising When performing the hot water supply only operation in which the first burner is burned without burning the second burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner. When performing the heating only operation in which the second burner is burned without burning the first burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the second burner. When performing the simultaneous operation in which the first burner and the second burner are burned, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner. When the temperature detected by the temperature sensor is equal to or lower than the threshold value, at least during the simultaneous operation, the pump control unit performs a dew condensation suppression operation of driving the pump at a rotation speed lower than the rotation speed corresponding to the combustion region and gas supply amount of the first burner. Hot water supply and heating machine.

[0012] In the hot water supply and heating machine of the above [1], since the first burner, the second burner, the first heat exchanger, and the second heat exchanger are housed in a common housing and air discharged from a common fan is supplied thereto, the device configuration can be simplified. And in this hot water supply and heating machine, when performing the simultaneous operation of burning the first burner and the second burner, the fan can be rotated at a rotation speed corresponding to the combustion region and gas supply amount of the first burner. Therefore, while simplifying the device configuration, the rotation speed of the fan can be accurately adjusted according to the gas supply amount on the hot water supply side.

[0013] However, in this water heater and space heater, since the fan is controlled according to the hot water supply side during simultaneous operation, the rotation speed of the fan may decrease according to the required combustion amount on the hot water supply side, and the combustion amount of the space heating burner may decrease. In this case, if the temperature of the heat medium circulating in the heat medium circulation path on the space heating side is low, the temperature of the combustion exhaust gas near the second heat exchanger on the space heating side may be excessively lowered, and condensation may occur around the second heat exchanger on the space heating side. Therefore, when the temperature detected by the temperature sensor during the simultaneous operation is equal to or lower than the threshold value, the water heater and space heater performs a dew condensation suppression operation to drive the pump at a rotation speed lower than the normal rotation speed. During this dew condensation suppression operation, since the amount of the heat medium passing through the second heat exchanger is suppressed, it is possible to suppress the excessive cooling of the combustion exhaust gas (the combustion exhaust gas generated by the second burner in the heating circuit) passing through the vicinity of the second heat exchanger by the heat medium circulating in the heat medium circulation path, and it is possible to suppress the occurrence of condensation in the vicinity of the second heat exchanger due to the excessive cooling of the combustion exhaust gas.

[0014] 〔2〕 When the temperature detected by the temperature sensor during the normal operation becomes equal to or lower than the threshold value while the simultaneous operation is being performed, the pump control unit performs the dew condensation suppression operation so as to gradually decrease the rotation speed of the pump. The water heater and space heater according to 〔1〕.

[0015] The water heater and space heater according to 〔2〕 above can prevent the amount of heat given to the heat dissipation terminal from dropping suddenly more than necessary compared with the case where the rotation speed of the pump is suddenly greatly decreased, and can suppress the delay in heat dissipation (delay in heating) of the heat dissipation terminal. Further, when the temperature detected by the temperature sensor returns to exceed the threshold value early after becoming equal to or lower than the threshold value, it is easy to stabilize the normal operation early.

[0016] 〔3〕 The terminal flow path through which the heat medium flows from the water heater and space heater includes a first terminal flow path and a second terminal flow path. As the heat dissipation terminal that supplies the heat medium from the water heater and space heater, it includes a first heat dissipation terminal that dissipates the heat of the heat medium flowing through the first terminal flow path, and one or a plurality of second heat dissipation terminals that dissipate the heat of the heat medium flowing through the second terminal flow path. As the switching valve, a first switching valve that switches between a state of blocking the supply of the heat medium to the first terminal flow path and a state of permitting it, and a second switching valve that switches between a state of blocking the supply of the heat medium to the second terminal flow path and a state of permitting it are included. When the number of the heat dissipation terminals that enter the heat dissipation state by switching at least one of the plurality of switching valves decreases, the pump control unit does not perform the dew condensation suppression operation. The hot water heating machine according to [1] or [2].

[0017] The hot water heating machine of the above [3] can be configured not to perform the dew condensation suppression operation when the number of heat dissipation terminals in the heat dissipation state (operation state) decreases, as in the case where the heating by any heat dissipation terminal is turned off. Even if the temperature of the heat medium circulation path detected by the temperature sensor is low, when the number of heat dissipation terminals in the heat dissipation state (operation state) decreases, the probability that the temperature of the heat medium flowing through the heat medium circulation path will rise earlier increases. Therefore, if, like the hot water heating machine of the above [3], the dew condensation suppression operation is not performed when the number of heat dissipation terminals in the heat dissipation state (operation state) decreases, it is possible to suppress the risk of dew condensation and secure a longer period of normal operation that can promote heating.

[0018] (4) The hot water heating machine according to any one of [1] to [3] including the second switching valve, the first heat dissipation terminal including the first switching valve, and a hot water heating system including the second heat dissipation terminal.

[0019] <First Embodiment> The following description relates to the hot water heating machine 1 according to the first embodiment. 1. Overall Configuration of the Hot Water Heating Machine 1 FIG. 1 is a schematic circuit diagram of the hot water heating machine 1. The hot water heating machine 1 mainly includes a hot water supply circuit 2, a heating circuit 3, a bath 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 hot water supply and heating unit 1 is provided with a housing 1A configured as a metal casing inside the housing, and a first combustion system unit 5 and a second combustion system unit 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 which is an example of a first burner, a heating burner 33A which is an example of a second burner, a hot water supply side heat exchanger 7 which is an example of a first heat exchanger, a heating side heat exchanger 32 which is an example of a second heat exchanger, and the like. The first combustion system unit 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 unit 6 is a combustion system that performs gas combustion and water heating during a heating operation or a supplementary heating operation.

[0021] The hot water supply circuit 2 is a circuit that heats water supplied from outside the hot water supply and heating unit 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 unit 5, and specifically includes a plurality of hot water supply burners 8A and the hot water supply side heat exchanger 7. A hot water supply combustion chamber 5A is provided in the first combustion system unit 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 pipe line 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 pipe line 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 control valve 13A, a water flow sensor 14, a hot water outlet pipe 10, a bypass pipe 12, a control valve 13B, a thermistor 15A (hot water supply inner cylinder thermistor), a thermistor 15B (hot water supply outlet thermistor), and the like. 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 pipe line 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 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 pipe line through which the hot water heated by the hot water supply side heat exchanger 7 flows. 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 supply side heat exchanger 7. A control valve 13B (bypass control valve) is provided in the bypass pipe 12. The 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.

[0025] 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 supply 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 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.

[0026] The hot water supply circuit 2 further includes a gas pipe 16, a main gas solenoid valve 17, a gas proportional control valve 18, and a hot water supply side solenoid valve 19. The gas pipe 16 is a pipe through which gas supplied from the outside of the hot water supply and heating machine 1 through 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 control valve 18 is provided downstream of the main gas solenoid valve 17. The downstream side of the gas proportional control 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. Each branch pipe 16A is provided with a hot water supply side solenoid valve 19 configured as a solenoid valve. The hot water supply side 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 hot water supply side solenoid valve 19. By switching the hot water supply side 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.

[0027] 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. The hot water supply circuit 2 is also provided with an igniter for ignition, an ignition electrode, a hot water supply flame rod, etc.

[0028] The bath circuit 4 includes a bath circulation path 63 and a bath heating side heat exchanger 50. The bath circulation path 63 forms a flow path configured to circulate the hot water derived from an external bathtub 52 and introduce it into the bathtub 52. The bath heating side heat exchanger 50 is configured as a liquid-liquid heat exchanger that performs heat exchange between the heat medium flowing through the bath heating pipe 51 and the hot water flowing through the bath circulation path 63.

[0029] The bath heating side heat exchanger 50 is provided with a pipe 50A that is a part of the bath circulation path 63, and the bath heating pipe 51 is arranged in the pipe 50A. The bath circulation path 63 is composed of the pipe 50A, the bath supply pipe 53, and the bath return pipe 54. When the bath circulation pump 55 is operating, the bath circulation path 63 functions as a flow path that draws hot water from the bathtub 52 installed outside the hot water heater 1, and functions as a flow path that circulates the drawn hot water and introduces it into the bathtub 52. The bath return pipe 54 is provided with the bath circulation pump 55 that flows the hot water in the bath return pipe 54 in a predetermined direction, and the water flow switch 57 that detects that the hot water is flowing in the bath return pipe 54 at a predetermined flow rate or more. The bath return pipe 54 is provided between the bathtub 52 outside the device and the pipe 50A, and forms a flow path that flows hot water from the bathtub 52 to the pipe 50A when the bath circulation pump 55 is operating. The bath supply pipe 53 is provided between the pipe 50A and the bathtub 52, and forms a flow path that allows hot and cold water to flow from the pipe 50A to the bathtub 52 when the bath circulation pump 55 is operating. The bath supply pipe 53 is provided with a bath supply thermistor 64 that detects the temperature of the hot and cold water flowing out from the bath heating side heat exchanger 50 to the bathtub 52. The bath return pipe 54 is provided with a bath return thermistor 65 that detects the temperature of the hot and cold water flowing from the bathtub 52 to the bath return pipe 54.

[0030] A drop pipe 59 is connected to the bath return pipe 54, branching off from the hot water outlet pipe 10. The drop pipe 59 is connected to the bath return pipe 54. The drop pipe 59 is provided with a hot water supply solenoid valve 60, a drop water volume sensor 61, and multiple check valves 62. When the hot water supply circuit 2 is in operation, the hot water supply solenoid valve 60 provided in the drop pipe 59 is opened, so that hot water heated in the hot water supply circuit 2 is supplied to the bathtub 52 through the drop pipe 59.

[0031] The heating circuit 3 is a circuit that can heat the heat medium by the heating-side heat exchanger 32 and supply the heat medium to the heating terminals (heat radiation terminals 39A and 39Z) via the heat medium circulation path 48. In the present embodiment, the heat medium is hot water. The heating circuit 3 includes the second combustion system unit 6 and the heat medium circulation path 48. In the second combustion system unit 6, a heating combustion chamber 6A is provided, 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. That is, the partitioning member 80 is configured as a member that partitions the inside of the housing 1A into a hot water supply combustion chamber 5A that houses the hot water supply burner 8A (first burner) and the hot water supply-side heat exchanger (first heat exchanger), and a heating combustion chamber 6A that houses the heating burner 33A (second burner) and the heating-side heat exchanger 32 (second heat exchanger). A combustion chamber temperature sensor 82 for detecting the temperature of the heating combustion chamber 6A is provided on the partitioning member 80. The partitioning member 80 is plate-shaped and is provided so as to partition between the hot water supply-side burner unit 8 and the hot water supply-side heat exchanger 7, and the heating-side burner unit 33 and the heating-side heat exchanger 32.

[0032] 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.

[0033] 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 first heating-side heat exchanger 32A and a second heating-side heat exchanger 32B. The first heating-side heat exchanger 32A has a plurality of fins 32Z. The second combustion system section 6 has the first heating-side heat exchanger 32A provided above a plurality of heating burners 33A, and the second heating-side heat exchanger 32B provided above the first heating-side 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 first heating-side heat exchanger 32A recovers sensible heat from the combustion exhaust gas discharged from the heating-side burner unit 33, and the second heating-side heat exchanger 32B recovers latent heat from the combustion exhaust gas discharged from the heating-side burner unit 33.

[0034] 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, and forms the flow path of the heat medium. The heat medium circulation path 48 includes 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 common pipe.

[0035] 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 38C, the first internal flow path 38A, and the first terminal flow path 38G of the first heat dissipation terminal 39A. 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 38C, the second internal flow path 38B, and the second terminal flow path 38H of the second heat dissipation terminal 39Z.

[0036] The heating circuit 3 further includes an expansion tank 36, a heating circulation pump 37, a heating high-temperature temperature sensor 40, and a heating low-temperature temperature sensor 41. The first internal flow path 38A is configured to communicate with the first heat dissipation terminal 39A and is connected to the first heat dissipation terminal 39A outside the appliance. The common flow path 38C is a pipe for flowing the heat medium flowing out from the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z through the heating-side heat exchanger 32 (the second heating-side 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 outside the appliance. Between the outlet of the second heating-side heat exchanger 32B and the inlet of the first heating-side heat exchanger 32A, there are an intermediate pipe 38D which is a part of the common flow path 38C and an intermediate pipe 38E which is a part of the common flow path 38C and the first internal flow path 38A. In the paths of the intermediate pipes 38D and 38E, the expansion tank 36 and the heating circulation pump 37 are provided. The intermediate pipe 38D is provided between the outlet of the second heating-side heat exchanger 32B and the expansion tank 36, and the intermediate pipe 38E is provided between the expansion tank 36 and the inlet of the first heating-side heat exchanger 32A. A heating circulation pump 37 is provided in the middle of the intermediate pipe 38E.

[0037] The second internal flow path 38B is provided with a configuration in which a plurality of internal branch paths 38F branch off. A second switching 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 dissipation terminal 39Z and is connected to the second heat dissipation terminal 39Z outside the appliance. The downstream sides of the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z communicate with the common flow path 38C. The first heat dissipation 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 dissipation terminal 39Z is, for example, a low-temperature heating terminal such as floor heating in a dressing room. The heat dissipation terminals 39A and 39Z can be turned on and off for heating (heat dissipation) and various settings regarding heating and the heating circulation pump 37 by a heating remote controller 73.

[0038] The heating high-temperature temperature sensor 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 heating-side heat exchanger 32A). The temperature detected by the heating high-temperature temperature sensor 40 corresponds to the temperature of the heat medium flowing into the first heat dissipation terminal 39A during the circulation of the heat medium passing through the first heat dissipation terminal 39A. The heating low-temperature temperature sensor 41 is provided in the expansion tank 36. The temperature detected by the heating low-temperature temperature sensor 41 corresponds to the temperature of the heat medium flowing into the second heat dissipation terminal 39Z during the circulation of the heat medium passing through the second heat dissipation terminal 39Z.

[0039] The heating circuit 3 includes a plurality of branch pipes 16B and a plurality of heating-side solenoid valves 44. As described above, the branch pipe 16B is provided in a configuration branched from the gas pipe 16 to the heating circuit 3 side. Each heating-side solenoid valve 44 is provided in each branch pipe 16B. The heating-side solenoid valve 44 is configured to switch the branch pipe 16B where it is provided between an open state (supply possible state) and a closed state (blocked state). The supply and cutoff of the fuel gas to each of the burner blocks 34A and 34B are individually switched by each heating-side solenoid valve 44. By adjusting the opening degree of the gas proportional control valve 18 along with the opening and closing of the heating-side solenoid valve 44, the supply amount of the combustion gas is adjusted. By switching the heating-side solenoid valve 44, the combustion range of the heating-side burner unit 33 is switched, and each combustion range is associated as a stage number. Note that the heating circuit 3 is also provided with an ignition electrode, a heating frame rod, and the like.

[0040] 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 also 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, the first heat dissipation terminal 39A is configured as a high-temperature heating terminal, and hot water is supplied to the first heat dissipation terminal 39A according to the operation of the first switching 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 switching valve 39G, which is a thermostatic valve inside the appliance.

[0041] As shown in FIG. 1, the bath heating pipe 51 is provided in a configuration branched from the first internal flow path 38A. The bath heating pipe 51 branches from a position on the downstream side of the heating-side heat exchanger 32 in the heat medium circulation path 48 (specifically, the downstream side of the first heating-side heat exchanger 32A), and forms a flow path for guiding the heat medium flowing through the heat medium circulation path 48 to the bath heating-side heat exchanger 50 side. The bath heating pipe 51 is connected between the first internal flow path 38A and the common flow path 38C so as to communicate with each other.

[0042] The control valve 58 is a valve provided on the upstream side of the bath heating-side heat exchanger 50 in the bath heating pipe 51. The control valve 58 is configured to open and close the bath heating pipe 51, and is configured to switch between a closed state in which the water flow passing through itself in the bath heating pipe 51 is blocked and an open state in which the water flow passing through itself in the bath heating pipe 51 is allowed. The control valve 58 has a switch. This switch is configured as a limit switch, and when the control valve 58 is in the fully open state where it is most open, it enters a first state in which a predetermined first signal (for example, an on signal) is output, and when the control valve 58 is in the fully closed state where it is blocked, it enters a second state in which a second signal (for example, an off signal) different from the first signal is output.

[0043] The water heater and heater 1 further includes a control device 70, a hot water supply remote controller 71, a bath remote controller 72, a heater 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 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 control device 70 corresponds to an example of a pump control unit and a combustion control unit, and functions to control the combustion of a hot water supply burner 8A (first burner) and a heating burner 33A (second burner), and to control the rotation speed of the fan 20. The room temperature thermistor is provided, for example, in the dressing room as a temperature detection means for detecting the temperature in the dressing room.

[0044] 2. Basic operation of the water heater and heater 1 (Normal hot water supply operation) When a hot water supply faucet provided outside the apparatus and communicating with the hot water outlet pipe 10 is opened and water is passed into the apparatus, and the water volume sensor 14 outputs a signal indicating water passage, 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 hot water supply side solenoid valve 19, and opens the gas proportional adjustment valve 18 at a predetermined opening degree to control the supply of 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 is heated by the combustion exhaust gas generated by the combustion and flows to the hot water outlet pipe 10, and the hot water heating operation is performed, and the heated hot water is discharged from the hot water supply faucet.

[0045] During the above hot water discharging operation, the control device 70 monitors the hot water temperature detected by the thermistor 15B provided in the hot water discharge pipe 10, and controls the opening and closing of the hot water supply side solenoid valve 19 and adjusts the opening degree of the gas proportional control valve 18 so that the hot water temperature becomes the set temperature indicated by the hot water supply remote control 71 or the bath remote control 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 discharging 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 hot water supply side solenoid valve 19 to extinguish the hot water supply burner 8A, and rotates the fan 20 for a predetermined time to perform post-purge.

[0046] (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 control 71 or the bath remote control 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 control 71 or the bath remote control 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 in the drop pipe 59 to put the hot water supply circuit 2 in a water flow state, and burns the hot water supply burner 8A so that the heated hot water flows into the hot water discharge pipe 10. The hot water flowing through the hot water discharge pipe 10 in this way is supplied to the bathtub 52 through the drop pipe 59 and the bath return pipe 54.

[0047] After the control device 70 starts supplying hot water to the bathtub 52 in this way, it monitors whether the water volume (total water volume since the start of automatic hot water filling) detected by the drop water volume sensor 61 provided in the drop pipe 59 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. Then, 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 control 71 or the bath remote control 72 of the end of the hot water filling.

[0048] (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 heating side 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 bath return thermistor 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.

[0049] 3. Combustion operation of the hot water supply and heating machine 1 (Hot water supply single operation) When the control device 70 performs a hot water supply single operation (an operation of burning the first burner without burning the second burner) in which the hot water supply side burner unit 8 is burned without burning the heating side burner unit 33, the control device 70 calculates the required combustion amount required by the hot water supply side burner unit 8 according to the temperature of the hot water detected by the thermistors 15A and 15B, and controls the opening degree of the gas proportional control valve 18 and the opening and closing of the hot water supply side solenoid valve 19 so as to obtain the calculated required combustion amount, thereby controlling the gas supply amount. When performing the above hot water supply single operation, the control device 70 rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the hot water supply burner (first burner). Specifically, the control device 70 controls the target rotation speed of the fan 20 so that the supply amount of combustion air corresponds to the gas supply amount. The gas supply amount is the "combustion amount" and the "input required amount".

[0050] More specifically, the control device 70 calculates the gas supply amount (input required amount) by a known calculation method based on the water amount (inlet water amount) detected by the water amount sensor 14, the set temperature set as the target temperature, and the temperature (outlet water temperature) detected by the thermistor 15B at each short time interval, updates the gas supply amount (input required amount) every calculation, and updates the fan rotation speed corresponding to the updated gas supply amount (input required amount). The calculation method of the gas supply amount (input required amount) may be a feedback calculation that brings the outlet water temperature closer to the set temperature. For example, it may be a method disclosed in Japanese Patent Application Laid-Open No. 2010-117053, or a method disclosed in Japanese Patent Application Laid-Open No. 2018-200123, or other known methods.

[0051] The control for changing the fan rotation speed every time the gas supply amount (input required amount) to the hot water supply side burner unit 8 is updated is executed according to an arithmetic expression or a table that defines the correspondence between the gas supply amount (combustion amount) and the fan rotation speed. In the example of FIG. 1, the burner blocks 9A, 9B, and 9C are composed of a plurality of burners with different numbers. Among the burner blocks 9A, 9B, and 9C, the number of gas burners in the burner block 9C is the largest, the number of gas burners in the burner block 9A is the smallest, the number of gas burners in the burner block 9B is less than that in the burner block 9C and more than that in the burner block 9A. In the hot water temperature control for controlling the outlet water temperature, the control device 70 performs single combustion of only the burner block 9A with the smallest number of burners in the first stage, then single combustion of only the burner block 9B with a larger number of burners in the second stage, then simultaneous combustion of the burner blocks 9A and 9B with an increasing number of burners in the third stage, then single combustion of the burner block 9C with an increasing number of burners in the fourth stage, and full combustion of the burner blocks 9A to 9C with the largest number of burners in the fifth stage, and executes switching control to switch the combustion stage (hereinafter, also referred to as the combustion stage or combustion step) of the hot water supply side burner unit 8 to five stages according to the required gas supply amount (input required amount).

[0052] In a representative example, for each combustion stage, the correspondence between the gas supply amount (input required amount) and the target rotational speed of the fan is determined in advance, and in the correspondence of any combustion stage, it is determined that the greater the gas supply amount (input required amount), the greater the target rotational speed. Information on the correspondence of each combustion stage is stored in a storage device provided in the control device 70 as an arithmetic expression or table for determining the target rotational speed based on the gas supply amount (input required amount). When the combustion stage and the gas supply amount are determined, the target rotational speed corresponding to the combustion stage and the gas supply amount is specified by the above information.

[0053] For example, in the above information, the upper limit value (first upper limit value) of the input required amount of the first-stage combustion stage is greater than the lower limit value (second lower limit value) of the input required amount of the second-stage combustion stage, and the upper limit value (second upper limit value) of the input required amount of the second-stage combustion stage is greater than the lower limit value (third lower limit value) of the input required amount of the third-stage combustion stage. The upper limit value (third upper limit value) of the input required amount of the third-stage combustion stage is greater than the lower limit value (fourth lower limit value) of the input required amount of the fourth-stage combustion stage, and the upper limit value (fourth upper limit value) of the input required amount of the fourth-stage combustion stage is greater than the lower limit value (fifth lower limit value) of the input required amount of the fifth-stage combustion stage. In the above information, the target rotational speed when the upper limit value (first upper limit value) of the input required amount of the first-stage combustion stage is greater than the target rotational speed when the lower limit value (second lower limit value) of the input required amount of the second-stage combustion stage. The target rotational speed when the upper limit value (second upper limit value) of the input required amount of the second-stage combustion stage is greater than the target rotational speed when the lower limit value (third lower limit value) of the input required amount of the third-stage combustion stage. The target rotational speed when the upper limit value (third upper limit value) of the input required amount of the third-stage combustion stage is greater than the target rotational speed when the lower limit value (fourth lower limit value) of the input required amount of the fourth-stage combustion stage. The target rotational speed when the upper limit value (fourth upper limit value) of the input required amount of the fourth-stage combustion stage is greater than the target rotational speed when the lower limit value (fifth lower limit value) of the input required amount of the fifth-stage combustion stage.

[0054] When the control device 70 is burning at any stage and the input required amount is below the lower limit value of that combustion stage, it switches to a stage lower than that combustion stage and determines the fan rotation speed corresponding to the input required amount according to the characteristics of the stage after switching. When the input required amount exceeds the upper limit value of that combustion stage, the control device 70 switches to a stage higher than that combustion stage and determines the fan rotation speed corresponding to the input required amount according to the characteristics of the stage after switching. For example, when burning in the first stage and the input required amount changes, and the required combustion amount exceeds the maximum value of the first stage, it switches to the second stage and burns the burner block 9B. When switching from the first stage to the second stage, it is set to the fan rotation speed corresponding to the input required amount according to the characteristic curve of the second stage. Similarly, when the input required amount changes in the second stage and the input required amount exceeds the maximum value of the second stage, it switches to the third stage and burns the burner blocks 9A and 9B. When switching from the second stage to the third stage, it is set to the fan rotation speed corresponding to the input required amount according to the characteristic curve of the third stage. Conversely, when the input required amount changes in the third stage and the input required amount is below the minimum value of the third stage, it switches to the second stage and burns the burner block 9B. When switching from the third stage to the second stage, it is set to the fan rotation speed corresponding to the input required amount according to the characteristic curve of the second stage.

[0055] (Heating only operation) When the control device 70 performs a heating-only operation (an operation of burning the heating-side burner unit 33 without burning the hot-water supply-side burner unit 8) (an operation of burning the second burner without burning the first burner), in accordance with the temperature of the heat medium detected by the thermistor, it calculates the required combustion amount required by the heating-side burner unit 33, and controls the opening degree of the gas proportional control valve 18 and the opening and closing of the heating-side solenoid valve 44 so as to obtain the obtained required combustion amount, thereby controlling the gas supply amount. And when the control device 70 performs the above-described hot-water supply-only operation, it rotates the fan at a rotation speed corresponding to the combustion region and the gas supply amount of the heating burner (the second burner). Specifically, it controls the target rotation speed of the fan 20 so as to obtain the supply amount of combustion air corresponding to the gas supply amount. The gas supply amount is the "combustion amount" and the "input required amount".

[0056] In the example of FIG. 1, the burner blocks 34A and 34B each consist of a plurality of burners with different numbers from each other. Among the burner blocks 34A and 34B, the burner block 34B has a larger number of gas burners than the burner block 34A, and the burner block 34A has a smaller number of gas burners. When the control device 70 burns the heating-side burner unit 33, it performs switching control to switch the combustion stage (hereinafter, also referred to as the combustion stage or combustion step) of the heating-side burner unit 33 in three stages, with the single combustion of only the burner block 34A with the smallest number of burners as the first stage, then the single combustion of only the burner block 34B with a larger number of burners as the second stage, and then the full combustion of the burner blocks 34A and 34B with an increasing number of burners as the third stage, according to the required gas supply amount (input required amount).

[0057] The number of steps switching in the heating-side burner unit 33 is also performed in the same manner as in the hot water supply-side burner unit 8. Regarding the heating-side burner unit 33 as well, for each combustion stage, the correspondence relationship between the gas supply amount (input required amount) and the target rotational speed of the fan is determined in advance. In the correspondence relationship of any combustion stage, it is determined that the higher the gas supply amount (input required amount), the higher the target rotational speed. Information on the correspondence relationship of each combustion stage is stored in a storage device or the like provided in the control device 70 as an arithmetic expression or a table for determining the target rotational speed based on the gas supply amount (input required amount). When the combustion stage and the gas supply amount are determined, the target rotational speed corresponding to the combustion stage and the gas supply amount is specified by the above information. Also in this example, the upper limit value (first upper limit value) of the input required amount in the first combustion stage is larger than the lower limit value (second lower limit value) of the input required amount in the second combustion stage, and the upper limit value (second upper limit value) of the input required amount in the second combustion stage is larger than the lower limit value (third lower limit value) of the input required amount in the third combustion stage. The target rotational speed at the upper limit value (first upper limit value) of the input required amount in the first combustion stage is larger than the target rotational speed at the lower limit value (second lower limit value) of the input required amount in the second combustion stage. The target rotational speed at the upper limit value (second upper limit value) of the input required amount in the second combustion stage is larger than the target rotational speed at the lower limit value (third lower limit value) of the input required amount in the third combustion stage. Also in this example, when burning at any stage, if the input required amount falls below the lower limit value of the current combustion stage, the control device 70 switches to a stage lower than the current combustion stage and determines the fan rotational speed corresponding to the input required amount according to the characteristics of the switched stage. When the input required amount exceeds the upper limit value of the current combustion stage, the control device 70 switches to a stage higher than the current combustion stage and determines the fan rotational speed corresponding to the input required amount according to the characteristics of the switched stage.

[0058] (Simultaneous operation) When the control device 70 simultaneously operates both the hot water supply side burner unit 8 and the heating side burner unit 33 (operation of burning the first burner and the second burner), the control of the gas supply amount to the hot water supply side burner unit 8 is performed in the same manner as in the case of hot water supply only operation, the control of the gas supply amount to the heating side burner unit 33 is performed in the same manner as in the case of heating only operation, and the control of the fan 20 is performed in the same manner as in the case of hot water supply only operation. That is, the fan 20 is rotated at a rotational speed corresponding to the combustion region and the gas supply amount of the hot water supply burner (first burner).

[0059] 4. Configuration for Radiating Heat from the First Heat Dissipation Terminal and the Second Heat Dissipation Terminal The hot water heating machine 1 shunts and supplies the heat medium to the external first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and constitutes a hot water supply system while being connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z.

[0060] As shown in FIG. 1, the downstream end of the common flow path 38C in the heat medium circulation path 48 is a branch portion 38J, 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 downstream end of the first internal flow path 38A is a first outflow portion 35B that can be connected to the outside and through which the heat medium flows out, and the downstream end of the second internal flow path 38B is a second outflow portion 35C that can be connected to the outside and through which the heat medium flows out. Further, the upstream end of the common flow path 38C is an inflow portion 35A that can be connected to the outside and through which the heat medium flows in.

[0061] Outside the water heater 1, a first heat radiation terminal 39A and a second heat radiation terminal 39Z are provided, to which a 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. The first heat radiation terminal 39A corresponds to an example of a heat radiation terminal, and the first terminal flow path 38G corresponds to an example of a terminal flow path. 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. The second heat radiation terminal 39Z corresponds to an example of a heat radiation terminal, and the second terminal flow path 38H corresponds to an example of a terminal flow path. The downstream end of the first terminal flow path 38G and the downstream end of the second terminal flow path 38H are connectable so as to communicate with the inflow portion 35A of the water heater 1. The inflow portion 35A serves as an inlet through which the heat medium that has flowed through the first terminal flow path 38G and the heat medium that has flowed through the second terminal flow path 38H flow in. The first outflow portion 35B serves as an outlet through which the heat medium flows out from the first internal flow path 38A to the first terminal flow path 38G, and the second outflow portion 35C serves as an outlet through which the heat medium flows out from the second internal flow path 38B to the second terminal flow path 38H.

[0062] 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 a first switching valve 39H (the first switching valve 39H corresponds to an example of a switching valve). 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 a second switching valve 39G (the second switching valve 39G corresponds to an example of a switching valve). Both the first switching valve 39H and the second switching 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 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.

[0063] The heat medium flowing into the inflow section 35A circulates through the heat medium circulation path 48 in the water heater 1. Specifically, the heat medium flows from the inflow section 35A into the common flow path 38C and moves downstream by the power of the heating circulation pump 37 within the common flow path 38C. After the heat medium is heated by the second heating-side heat exchanger 32B in the middle of the common flow path 38C, it is divided, via the expansion tank 36, into the heat medium heading towards the first internal flow path 38A and the heat medium heading towards the second internal flow path 38B at the branch section 38J. The heat medium flowing through the first internal flow path 38A is heated by the first heating-side heat exchanger 32A on the way.

[0064] The refrigerant flowing through the first internal flow path 38A is discharged towards the first terminal flow path 38G with the first outflow section 35B as the outlet. The heat medium flowing through the second internal flow path 38B is discharged towards the second terminal flow path 38H with the second outflow section 35C as the outlet.

[0065] The first switching valve 39H that opens and closes the first terminal flow path 38G, the second switching 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 so as to be controllable with respect to each of the first switching valve 39H, the second switching valve 39G, and the heating circulation pump 37, and performs the opening and closing of the first switching valve 39H and the second switching valve 39G and the drive control of the heating circulation pump 37.

[0066] 5. Configuration for suppressing condensation in the heating circuit 3 The heat medium passing through the inside of the heating-side heat exchanger 32 is heated by the heating burner 33A, and the detected temperature TA of the heat medium in the heat medium circulation path 48 detected by the heating high-temperature temperature sensor 40, which is an example of a temperature sensor, is input to the control device 70, which is an example of a pump control unit.

[0067] In the memory of the control device 70, there are stored an arithmetic formula for rotating a heating circulation pump 37, which is an example of a pump, at a predetermined rotational speed RN0 (normal rotational speed), and a predetermined threshold value TH that serves as a criterion for determining whether to perform a dew condensation suppression operation for reducing the rotational speed of the heating circulation pump 37 described later. The "predetermined rotational speed RN0" of the heating circulation pump 37 is the rotational speed of the heating circulation pump 37 during normal heating operation, and is obtained based on the total value of the required heat quantity for radiating heat from the heat dissipation terminals 39A and 39Z, and the calculation result based on the detected temperature TA detected by the heating high temperature temperature sensor 40. The calculation based on the detected temperature TA can use, for example, one or both of the calculation results for feedforward control based on the detected temperature TA and the calculation results for feedback control of the detected temperature TA.

[0068] The threshold value TH is a value that serves as a criterion for determining whether to execute the dew condensation suppression operation. The dew condensation suppression operation is a control in which the control device 70 reduces the operating speed of the heating circulation pump 37 in order to suppress the occurrence of dew condensation. In the dew condensation suppression operation, although it will be described in detail later, the rotational speed of the heating circulation pump 37 (of the motor) is gradually reduced compared to the normal operation (Fig. 3).

[0069] If the threshold value TH is set too high, when the detected temperature TA is relatively high, the detected temperature TA is likely to be lower than the threshold value TH, so there is a high possibility of performing the dew condensation suppression operation of reducing the rotational speed of the heating circulation pump 37 when the possibility of dew condensation occurring is low, and there is a risk that the heat medium in the heat medium circulation path 48 becomes too high and causes problems such as boiling. On the other hand, if the threshold value TH is set too low, when the detected temperature TA is relatively low, the detected temperature TA is likely to be higher than the threshold value TH, so there is a problem that the dew condensation suppression operation is not performed when the possibility of dew condensation occurring is high. Therefore, the threshold value TH is appropriately set to a value that can prevent the heat medium in the heat medium circulation path 48 from becoming too high and can suppress the occurrence of dew condensation at low temperatures.

[0070] The heating circulation pump 37 is a centrifugal pump, but it is not limited to this, and other pumps such as a propeller pump may be used. The heating circulation pump 37 is provided with a drive motor, and the rotational speed of the drive motor is controlled by the control device 70. As the drive motor, an AC motor or a DC motor can be used. The drive motor is connected to, for example, an inverter device, so that the commercial voltage is converted into an arbitrary voltage and frequency, and the heating circulation pump 37 can be rotated at an arbitrary rotational speed. Then, according to the signal from the control device 70, by increasing or decreasing the rotational speed of the drive motor, the water supply amount (circulation amount) of the heat medium (hot water) in the heat medium circulation path 48 can be increased or decreased.

[0071] When the heating circuit 3 performs a heating operation, the control device 70 calculates the required combustion amount required by the heating side burner unit 33 according to the temperature of the hot water detected by the temperature sensors 40 and 41, and in order to obtain the calculated required combustion amount, it controls the opening degree of the gas proportional control valve 18 and the opening and closing of the heating side solenoid valve 44 to adjust the gas supply amount. Also, when the hot water supply circuit 2 performs a hot water supply operation, the control device 70 calculates the required combustion amount required by the hot water supply side burner unit 8 according to the temperature of the hot water detected by the temperature sensors 40 and 41, and in order to obtain the calculated required combustion amount, it controls the opening degree of the gas proportional control valve 18 and the opening and closing of the hot water supply side solenoid valve 19 to adjust the gas supply amount. The fan 20 controls the target rotational speed so that the supply amount of combustion air corresponds to the gas supply amount.

[0072] 6. Control of the rotational speed of the fan 20 by the control device 70 When the operation start condition for starting the operation of at least one of the hot water supply circuit and the heating circuit is satisfied in a state where the operations of the hot water supply circuit and the heating circuit are stopped, the control device 70 starts the control of FIG. 2. After starting the control of FIG. 2, the control device 70 determines in step S11 whether the condition for operating the hot water supply circuit and the heating circuit simultaneously is satisfied. When the control device 70 determines in step S11 that the condition for simultaneous operation is satisfied, the process proceeds to step S12, and when it determines that the condition for simultaneous operation is not satisfied, the process proceeds to step S17 to perform single operation. The single operation is either the above-described hot water supply single operation or the above-described heating single operation.

[0073] When the control device 70 determines in step S11 that it is a simultaneous operation and proceeds with the process to step S12, it determines in step S12 whether the detected temperature TA detected by the heating high-temperature temperature sensor 40 is equal to or lower than a predetermined threshold value TH. When the control device 70 determines that the detected temperature TA is higher than the predetermined threshold value TH (No in step S12), since the temperature of the heat medium is relatively high and the possibility of condensation occurring is low, the process proceeds to step S16, and normal operation is performed for the heating circulation pump 37. Specifically, in normal operation, the control device 70 controls the heating circulation pump 37 to reach a predetermined rotation speed (normal rotation speed) according to a predetermined arithmetic expression for normal operation that is set in advance and stored in the memory.

[0074] When the control device 70 determines in step S12 that the detected temperature TA is equal to or lower than the predetermined threshold value TH (Yes in step S12), the process proceeds to step S13, and it is determined whether the number of heat dissipation terminals in the heat dissipation state (heating state) has decreased within a predetermined time. The "predetermined time" in step S13 is set to a time when condensation is likely to occur due to the decrease in the heat dissipation terminals. The "predetermined time" may be stored in the memory of the control device 70 in advance (such as at the time of shipment), but is not limited thereto, and the user may be able to set an arbitrary time from a heating remote control or the like.

[0075] When the number of heat dissipation terminals 39A and 39Z in the heat dissipation state (heating state) decreases within a specified time (Yes in step S13), the process proceeds to step S16 and the heating circulation pump 37 is operated normally. When the number of heat dissipation terminals 39A and 39Z decreases, the heat dissipation amount at the heat dissipation terminals 39A and 39Z decreases, so the temperature drop of the heat medium in the heat medium circulation path 48 is suppressed and dew condensation on the heating side heat exchanger 32 is less likely to occur. Since it is not necessary to reduce the rotation speed of the heating circulation pump 37, normal operation is performed. For example, when both the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z are being heated, if one of the heat dissipation terminals is turned off by the heating remote control 73 or the like, or when a plurality of second heat dissipation terminals 39Z are being heated and one or more of the second heat dissipation terminals 39Z are turned off, normal operation is performed.

[0076] When there is no decrease in the number of heat dissipation terminals in the heat dissipation state (heating state) within a specified time (in the case of No in step S13), the process proceeds to step S14, and dew condensation suppression operation is performed on the heating circulation pump 37. In the dew condensation suppression operation, the rotation speed of the heating circulation pump 37 is decreased compared to normal operation. When the heat dissipation terminals 39A and 39Z are in the on state, the heat of the heat medium in the heat medium circulation path 48 is consumed by the heat dissipation terminals 39A and 39Z in the on state according to the number of the heat dissipation terminals 39A and 39Z in the on state, and the temperature of the heat medium in the heat medium circulation path 48 has decreased, and it is in a state where dew condensation is likely to occur. Therefore, in order to suppress the temperature decrease of the heat medium in the heat medium circulation path 48, the rotation speed of the heating circulation pump 37 is decreased by the dew condensation suppression operation. When the temperature detected by the heating high-temperature temperature sensor 40 becomes equal to or lower than a predetermined threshold value TH, the rotation speed of the heating circulation pump 37 is decreased below a predetermined rotation speed RN0 (that is, by decreasing it to a rotation speed lower than the rotation speed corresponding to the combustion region and gas supply amount of the hot water supply burner 8A (first burner) during normal operation in simultaneous operation (when the temperature detected by the heating high-temperature temperature sensor 40 is higher than the predetermined threshold value TH)), the amount of the heat medium passing through the heating-side heat exchanger 32 in the heat medium circulation path 48 decreases, so that the temperature of the combustion exhaust generated by the heating burner 33A of the heating circuit 3 is not excessively lowered by the heat medium circulating in the heat medium circulation path 48 of the heating circuit 3. As a result, it is possible to suppress the occurrence of dew condensation around the heating-side heat exchanger 32 due to the temperature decrease of the combustion exhaust generated by the heating burner 33A.

[0077] Here, the rotational speed of the heating circulation pump 37 during the dew condensation suppression operation decreases step by step as shown in FIG. 3. With respect to the rotational speed RN0 of the heating circulation pump 37 during normal operation (from T0 to T1), the rotational speed of the heating circulation pump 37 decreases to the first rotational speed RN1 at the timing of T1. From T1 to T2, the rotational speed of the heating circulation pump 37 is maintained at the first rotational speed RN1, and the rotational speed of the heating circulation pump 37 decreases to the second rotational speed RN2 at the timing of T2. From T2 to T3, the rotational speed of the heating circulation pump 37 is maintained at the third rotational speed RN3, and the rotational speed of the heating circulation pump 37 decreases to the third rotational speed RN3 (rotational speed of low-speed operation) at the timing of T3. After T3, the third rotational speed RN3 is maintained. Then, at the timing of returning to normal operation (the timing when the detected temperature TA becomes greater than the threshold value TH or the number of heat dissipation terminals decreases), it returns to the rotational speed RN0 of normal operation. Note that in FIG. 3, the rotational speed decreases in three steps, but it is not limited to this, and it may be controlled to decrease in two steps or four or more steps. Also, the rotational speed of the heating circulation pump 37 is not limited to a stepwise decrease. For example, the rotational speed may be decreased to a predetermined value in proportion to time, or may be decreased to a predetermined value at once. The specific calculation method of the rotational speed (rotational speed during the dew condensation suppression operation) is, for example, a normal arithmetic expression (for example, the calculation result for feedforward control based on the detected temperature TA and / or one or both of the calculation results for feedback control of the detected temperature TA) obtained based on the total value of the required heat quantity for dissipating heat from the heat dissipation terminals 39A and 39Z, and the detected temperature TA detected by the heating high-temperature temperature sensor 40. A coefficient may be multiplied so that the output (rotational speed) decreases, or a different arithmetic expression may be used so that the rotational speed decreases.

[0078] After normal operation or dew condensation suppression operation is performed, the control device 70 determines whether or not the operation end condition is satisfied in step 15. The operation end condition is a condition for ending the operations of both the hot water supply circuit and the heating circuit. When the operation end condition is satisfied (No in step S15), the control device 70 returns to step S12 and performs the same processing as above. When the operation end condition is satisfied (Yes in step S15), the processing ends.

[0079] 7. Examples of Effects When the operation start instructions for the hot water supply circuit 2 and the heating circuit 3 are given, the combustion of the hot water supply burner 8A and the heating burner 33A is performed by gas, and combustion air is supplied into the housing 1A by the fan 20. Further, when the supply of the heat medium to the terminal flow paths 38G and 38H is permitted by the switching valves 39H and 39G for heat dissipation of the heat dissipation terminal, during normal times when the temperatures detected by the temperature sensors 40 and 41 are higher than a predetermined threshold value TH, the heating circulation pump 37 is driven at a predetermined rotation speed RN0. As a result, the heat medium in the heat medium circulation path 48 circulates by the force of the heating circulation pump 37, and when the heat medium passes through the heating side heat exchanger 32, the heat of the combustion exhaust gas is transmitted to the heat medium of the heating side heat exchanger 32, reducing the temperature of the combustion exhaust gas and increasing the temperature of the heat medium in the heat medium circulation path 48 detected by the temperature sensors 40 and 41.

[0080] On the other hand, when the rotation speed of the fan 20 decreases and the combustion amount of the heating burner 33A decreases, the temperature of the combustion exhaust gas of the heating burner 33A is excessively decreased by the heat medium circulating in the heat medium circulation path 48 of the heating circuit 3, and the possibility of dew condensation occurring increases.

[0081] Therefore, when the combustion amount of the heating burner 33A decreases, the temperature of the heat medium in the heat medium circulation path 48 decreases. Thus, when the temperatures detected by the temperature sensors 40 and 41 become equal to or lower than the predetermined threshold value TH, the rotation speed of the heating circulation pump 37 is decreased below the predetermined rotation speed RN0. As a result, the amount of the heat medium passing through the heating side heat exchanger 32 in the heat medium circulation path 48 decreases, so that the temperature of the combustion exhaust gas generated by the heating burner 33A of the heating circuit 3 is not excessively decreased by the heat medium circulating in the heat medium circulation path 48 of the heating circuit 3, and the possibility of causing a temperature drop sufficient to cause dew condensation in the heating side heat exchanger 32 is reduced. Therefore, it is possible to suppress dew condensation from occurring around the heating side heat exchanger 32 due to the temperature drop of the combustion exhaust gas generated by the heating burner 33A.

[0082] <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 stated as essential. Furthermore, the above-described embodiments may be modified as follows.

[0083] In the above-described embodiment, the detection temperature TA of the heating high-temperature temperature sensor 40 as a temperature sensor was compared with the threshold value TH to control the heating circulation pump 37, but it is not limited to this. For example, the detection temperature TA of the heating low-temperature temperature sensor 41 as a temperature sensor may be compared with the threshold value TH to control the heating circulation pump 37. When comparing the detection temperature of the heating low-temperature temperature sensor 41 with the threshold value, a threshold value (low-temperature threshold value) corresponding to the low-temperature detection temperature TA of the heating low-temperature temperature sensor 41 may be set. Also, the temperature sensor that detects the temperature of the heat medium is not limited to the heating high-temperature temperature sensor 40 or the heating low-temperature temperature sensor 41, and may be other sensors or the like provided in the heat medium circulation path 48. In this case, an appropriate threshold value (not shown) is appropriately set according to the position of the temperature sensor in the heat medium circulation path 48.

[0084] 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 changes within the scope indicated by the claims or within the scope equivalent to the claims are included.

Explanation of Reference Numerals

[0085] 1: Water heater 1A: Container 2: Hot water supply circuit 3: Heating circuit 4: Bath circuit 5A: Hot water supply combustion chamber 6A: Heating combustion chamber 7: Hot water supply side heat exchanger (first heat exchanger) 7Z: Fin 8: Hot water supply side burner unit 8A: Hot water burner (First burner) 9A: Burner block 9B: Burner block 9C: Burner block 10: Hot water outlet pipe 11: Water supply pipe 20: Fan 20A: Drive source 20B: Rotating body 32: Heating side heat exchanger (Second heat exchanger) 32: First heating side heat exchanger 32: Second heating side heat exchanger 33: Heating side burner unit 33A: Heating burner (Second burner) 34A: Burner block 34B: Burner block 35A: Inlet part 35B: First outlet part 35C: Second outlet part 36: Expansion tank 37: Heating circulation pump (Pump) 38A: First internal flow path 38B: Second internal flow path 38C: Common flow path 38J: Branch part 39A: First heat dissipation terminal (Heat dissipation terminal) 39Z: Second heat dissipation terminal (Heat dissipation terminal) 38G: First terminal flow path (Terminal flow path) 38H: Second terminal flow path (Terminal flow path) 39H: First switching valve (Switching valve) 39G: Second switching valve (Switching valve) 40: Heating high temperature temperature sensor (Temperature sensor) 41: Heating low temperature temperature sensor 48: Heat medium circulation path 70: Control device (Pump control unit, Combustion control unit) 73: Heating remote control 80: Partition member TA: Detected temperature TH: Threshold value

Claims

1. A water heater that supplies a heat medium to a heat dissipation terminal having a terminal flow path through which the heat medium flows and that dissipates the heat of the heat medium flowing through the terminal flow path, and controls a switching valve that switches between a state in which the supply of the heat medium to the terminal flow path is blocked and a state in which it is permitted, comprising a first burner that burns gas, and a first heat exchanger that is heated by the exhaust gas generated by the first burner, and a hot water supply circuit that heats water supplied from the outside by the first heat exchanger and supplies hot water, a second burner that burns gas, a second heat exchanger that is heated by the exhaust gas generated by the second burner, a path for circulating the heat medium together with the terminal flow path, a heat medium circulation path that passes through the second heat exchanger, and a pump that causes the heat medium to flow in the heat medium circulation path, and a heating circuit that heats the heat medium by the second heat exchanger and supplies the heat medium to the terminal flow path via the heat medium circulation path, a housing that houses the first burner, the second burner, the first heat exchanger, and the second heat exchanger, a partition member that partitions the inside of the housing into a hot water supply combustion chamber that houses the first burner and the first heat exchanger and a heating combustion chamber that houses the second burner and the second heat exchanger, a fan that supplies air into the housing, a combustion control unit that controls the combustion of the first burner and the second burner and controls the rotation speed of the fan, a temperature sensor that detects the temperature of the heat medium circulation path, a pump control unit that performs normal operation so as to rotationally drive the pump in a state in which the supply of the heat medium to the terminal flow path is permitted by the switching valve, and is provided with, when performing a hot water supply only operation in which the first burner is burned without burning the second burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner, and when performing a heating only operation in which the second burner is burned without burning the first burner, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the second burner, and when performing a simultaneous operation in which the first burner and the second burner are burned, the combustion control unit rotates the fan at a rotation speed corresponding to the combustion region and gas supply amount of the first burner, when the temperature detected by the temperature sensor is equal to or lower than a threshold value, at least during the simultaneous operation, the pump control unit performs a dew condensation suppression operation of driving the pump at a rotation speed lower than the rotation speed corresponding to the combustion region and gas supply amount of the first burner Water heater.

2. When the temperature detected by the temperature sensor during the normal operation is equal to or lower than the threshold value while the simultaneous operation is being performed, the pump control unit performs the dew condensation suppression operation so as to gradually decrease the rotation speed of the pump. The water heater according to claim 1.

3. The terminal flow path through which the heat medium flows from the water heater includes a first terminal flow path and a second terminal flow path. As the heat dissipation terminal that supplies the heat medium from the water heater, it includes a first heat dissipation terminal that dissipates the heat of the heat medium flowing through the first terminal flow path, and one or a plurality of second heat dissipation terminals that dissipate the heat of the heat medium flowing through the second terminal flow path. As the switching valve, it includes a first switching valve that switches between a state of blocking the supply of the heat medium to the first terminal flow path and a state of permitting it, and a second switching valve that switches between a state of blocking the supply of the heat medium to the second terminal flow path and a state of permitting it. When the number of the heat dissipation terminals that enter the heat dissipation state decreases due to the switching of at least one of the plurality of switching valves, the pump control unit does not perform the dew condensation suppression operation. The water heater according to claim 1 or claim 2.

Images