Hot water supply heater

Abstract

To provide a technology capable of effectively removing air from a heat medium flowing in a hot water supply heater.SOLUTION: A hot water supply heater 1 controls a first valve 39H that switches between a state in which supply of a heat medium to a first terminal flow path 38G is blocked and a state in which the supply is allowed, and a second valve 39G that switches between a state in which supply of heat medium to a second terminal flow path 38H is blocked and a state in which the supply is allowed, where a control unit performs a first process of operating a heating circulation pump 37 while keeping one of the first valve 39H and the second valve 39G in an open state and the other in a closed state, after the first process, performs a second process of stopping the operation of the heating circulation pump 37 for a first period of time, and after the first process and the second process, performs a third process of operating the heating circulation pump 37 while keeping the one valve in a closed state and the other valve in an open state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a hot water heater. [Background technology]

[0002] Patent Document 1 describes a hot water heating system. This hot water heating system includes a cistern, a heating heat exchanger, a circulation pump, and a control unit inside a housing. The cistern, the heating heat exchanger, and the circulation pump are connected by piping. The piping branches downstream of the heating heat exchanger, and one of the branches is connected to the cistern via an external floor heating panel. The other branch is connected to the cistern via a reheating heat exchanger.

[0003] The hot water in the cistern is sent by a circulation pump to the heating heat exchanger, where it is heated. It is then sent to the external floor heating panel and reheating heat exchanger. The hot water that has dissipated heat in the floor heating panel is returned to the cistern. The hot water that has exchanged heat in the reheating heat exchanger is also returned to the cistern. The reheating heat exchanger is connected to the bathtub via piping.

[0004] In addition, a thermal valve is provided in the piping connected to the floor heating panel and in the piping connected to the bathtub, and the circulation of hot and cold water is controlled by opening and closing the thermal valve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-195311 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a hot water heater that can circulate a heat medium to supply it to a heat dissipation terminal, air is likely to be mixed into the heat medium, and there is a concern that the air mixed into the heat medium may have adverse effects. In this regard, the hot water heater system in Patent Document 1 runs a pump for 10 minutes every 30 days (every 720 hours) to perform an air removal operation that circulates the water in the circulating heating circuit, and removes air from the water that has passed through the heating tank.

[0007] However, in a hot water heater or heating device in which multiple flow paths are branched off to supply a heat medium to multiple heat dissipation terminals, with some of the flow paths being common to form a heat medium circulation path, since the branched flow paths are connected by a common flow path, there is a concern that when the heat medium is caused to flow to remove air, air mixed with the heat medium in one flow path may move to the other flow path.

[0008] One object of the present disclosure is to provide a technology that can more effectively remove air from the heat transfer medium flowing inside a hot water heater. [Means for solving the problem]

[0009] A hot water heater according to the present disclosure supplies a heat medium to a first heat dissipation terminal having a first terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the first terminal flow path, and a second heat dissipation terminal having a second terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the second terminal flow path; A hot water heater that controls a first valve that switches between a state in which the supply of the heat medium to the first terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is blocked and a second valve that switches between a state in which the supply of the heat medium to the second terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is permitted, an inlet portion that is provided downstream of the first terminal flow path and downstream of the second terminal flow path and into which the heat medium that has flowed through the first terminal flow path and the heat medium that has flowed through the second terminal flow path flow; a common flow path for passing the heat transfer medium that has flowed into the inlet portion; a branching portion provided at an end of the common flow path and branching the flow of the heat medium that has flowed through the common flow path; A first internal flow path that is configured as a flow path branched from the branching portion and that is a flow path that flows the heat medium to the first heat dissipation terminal; A second internal flow path that is configured as a flow path branched from the branching portion and that is a flow path that flows the heat medium to the second heat dissipation terminal; A first outlet portion is provided at a downstream end of the first internal flow path and serves as an outlet for discharging the heat medium toward the first terminal flow path; A second outlet portion is provided at a downstream end of the second internal flow path and serves as an outlet for discharging the heat medium toward the second terminal flow path; A pump for causing the heat medium to flow in the common flow path; a tank provided in the common flow path and through which the heat medium flows through the common flow path; a first heat exchanger that heats the heat medium flowing through the first internal flow path; a control unit that controls the first valve, the second valve, and the pump; Equipped with The control unit performs a first process of operating the pump while keeping one of the first valve and the second valve in an open state and the other valve in a closed state, performs a second process of stopping the operation of the pump for a first period after the first process, and performs a third process of operating the pump while keeping the one valve in a closed state and the other valve in an open state after the first process and the second process. Effect of the Invention

[0010] The technology disclosed herein can more effectively remove air from the heat transfer medium flowing inside the hot water heater. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic circuit diagram illustrating a configuration of a hot water heater according to a first embodiment. [Diagram 2] FIG. 2 is a flow chart showing a process for removing air from the heat medium flowing inside the hot water heater 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Each of the following [1] to [4] is an example of a hot water heater included in the present disclosure. [1] A heat medium is supplied to a first heat dissipation terminal having a first terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the first terminal flow path, and a second heat dissipation terminal having a second terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the second terminal flow path; A hot water heater that controls a first valve that switches between a state in which the supply of the heat medium to the first terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is blocked and a second valve that switches between a state in which the supply of the heat medium to the second terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is permitted, an inlet portion that is provided downstream of the first terminal flow path and downstream of the second terminal flow path and into which the heat medium that has flowed through the first terminal flow path and the heat medium that has flowed through the second terminal flow path flow; a common flow path for passing the heat transfer medium that has flowed into the inlet portion; a branching portion provided at an end of the common flow path and branching the flow of the heat medium that has flowed through the common flow path; A first internal flow path that is configured as a flow path branched from the branching portion and that is a flow path that flows the heat medium to the first heat dissipation terminal; A second internal flow path that is configured as a flow path branched from the branching portion and that is a flow path that flows the heat medium to the second heat dissipation terminal; A first outlet portion is provided at a downstream end of the first internal flow path and serves as an outlet for discharging the heat medium toward the first terminal flow path; A second outlet portion is provided at a downstream end of the second internal flow path and serves as an outlet for discharging the heat medium toward the second terminal flow path; A pump for causing the heat medium to flow in the common flow path; a tank provided in the common flow path and through which the heat medium flows through the common flow path; a first heat exchanger that heats the heat medium flowing through the first internal flow path; a control unit that controls the first valve, the second valve, and the pump; Equipped with The control unit performs a first process of operating the pump while keeping one of the first valve and the second valve in an open state and the other valve in a closed state, performs a second process of stopping the operation of the pump for a first time after the first process, and performs a third process of operating the pump while keeping the one valve in a closed state and the other valve in an open state after the first process and the second process. Hot water heater.

[0013] In the hot water heater of the above [1], the heat medium in the common flow path can be branched into a first internal flow path and a second internal flow path from a branching portion provided at the downstream end of the common flow path. The first heat exchanger is capable of heating the heat medium flowing through the first internal flow path, and a first outlet portion is provided at the downstream end of the first internal flow path, and the heat medium flowing out from the first outlet portion can flow to the inlet portion through a first terminal flow path in the first heat dissipation terminal. The second internal flow path is provided at the downstream end, and the heat medium flowing out from the second outlet portion can flow to the inlet portion through a second terminal flow path in the second heat dissipation terminal. With this configuration, a circulation path in which the heat medium circulates through the common flow path, the first internal flow path, and the first terminal flow path, and a circulation path in which the heat medium circulates through the common flow path, the second internal flow path, and the second terminal flow path are configured. In this configuration, the heat medium that flows from the branching portion into the first internal flow path and the second internal flow path passes through the first terminal flow path in the first heat dissipation terminal and the second terminal flow path in the second heat dissipation terminal, respectively, and joins at the inflow portion. In the configuration described above, for example, at the portion where the flow path on the first heat dissipation terminal side and the flow path on the second heat dissipation terminal side join at the inflow portion side, there is a concern that air in one flow path may mix with the flow path on the other side.

[0014] Regarding this problem, in the first process, the hot water heater operates the pump while opening one of the first valve and the second valve and closing the other valve. That is, in the first process, the heat medium flows in a circulation path including the common flow path, one internal flow path, and one terminal flow path, and air is removed from the heat medium. In the first process, the other valve is closed, so that the flow of the heat medium is suppressed in the other internal flow path and the other terminal flow path, and the intrusion of air into the other internal flow path and the other terminal flow path is suppressed. Furthermore, after the first process, the hot water heater performs a third process, and operates the pump while opening the other of the first valve and the second valve and closing the other valve. That is, in the third process, the heat medium flows in a circulation path including the common flow path, the other internal flow path, and the other terminal flow path, and air is removed from the heat medium. During the third process, one of the valves is kept closed, thereby suppressing the flow of heat transfer medium in one of the internal flow paths and one of the terminal flow paths, and preventing air from entering one of the internal flow paths or one of the terminal flow paths.

[0015] In this way, the hot water heater can bleed air from both the first internal flow path and the first terminal flow path and the second internal flow path and the second terminal flow path, and when bleed air from one path, it can reliably prevent air from entering the other path. Furthermore, since the hot water heater performs the second process of stopping the operation of the pump for a first time after the first process and before the third process, it is possible to secure time that can be used for switching control of the first valve and the second valve after the first process and before the third process. Therefore, the hot water heater can easily prevent an unstable state of the third process caused by a lack of time between the end of the first process and the start of the third process (such as an unstable state caused by switching of the first valve and the second valve not being reliably completed).

[0016] [2] The first valve is a first thermal valve, the second valve is a second thermal valve; The control unit controls the one valve to be in a closed state during the second process after the first process, and starts the third process after the one valve is switched to the closed state during the second process. The hot water heater according to [1].

[0017] In the hot water heater of [2], when a first thermal valve is used as the first valve and a second thermal valve is used as the second valve, the thermal valve has the property of opening and closing at a slow speed, so in the above-mentioned device using thermal valves, if the third process is started immediately after the first process, there is a concern that the period during which the heat medium flows in the state where one thermal valve starts to close and closes completely, and the other thermal valve starts to open and opens completely, will be long. If such a period is long, the heat medium before the air is removed from the path where the air is removed in the third process will easily enter the path where the air was removed in the first process.

[0018] Regarding this problem, the hot water heater can start the third process after one of the valves has switched to a closed state during the second process after the first process, thereby reliably preventing the heat medium before air is bled from the path where air is bled in the third process from entering the path where air was bled in the first process.

[0019] [3] A second heat exchanger is provided for heating a part of the common flow path; The first heat exchanger heats a heat medium inside the first internal flow path by using sensible heat of exhaust gas generated by a burner that combusts gas, The second heat exchanger heats the heat medium inside the common flow passage by using latent heat of the exhaust gas generated by the burner. A hot water heater according to [1] or [2].

[0020] [4] The first heat dissipation terminal having the first valve; One or more of the second heat dissipation terminals; The hot water heater according to any one of [1] to [3], which is provided with the second valve; A hot water heating system comprising:

[0021] First Embodiment The following description relates to a hot water heater 1 according to the first embodiment. 1. Overall configuration of hot water heater 1 Fig. 1 is a schematic circuit diagram of a hot water heater 1. The hot water heater 1 is mainly equipped with a hot water 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, reheating operations, heating operations, etc.

[0022] The hot water heater 1 has a housing in which a container 1A configured as a metal casing is provided, and a first combustion system section 5 and a second combustion system section 6 are configured inside the container 1A. The container 1A is configured as, for example, a metal can body or a metal box body, and is configured to accommodate a hot water supply burner 8A, a heating burner 33A, a hot water supply side heat exchanger 7, a heating side heat exchanger 32, etc. The first combustion system section 5 is a combustion system that combusts gas and heats water when the hot water supply circuit 2 performs a hot water supply operation. The second combustion system section 6 is a combustion system that combusts gas and heats water during a heating operation or a reheating operation.

[0023] The hot water supply circuit 2 is a circuit that supplies hot water by heating water supplied from outside the hot water heater 1 using a hot water supply side heat exchanger 7. The hot water supply circuit 2 includes a first combustion system section 5, and more specifically, includes a plurality of hot water supply burners 8A and a hot water supply side heat exchanger 7. A hot water supply combustion chamber 5A is provided in the first combustion system section 5, and a hot water supply side burner unit 8 and a hot water supply side heat exchanger 7 are provided in the hot water supply combustion chamber 5A. Hot water supply side burner unit 8 includes burner blocks 9A, 9B, and 9C, and each of burner blocks 9A, 9B, and 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.

[0024] The hot water supply side heat exchanger 7 is a heat exchanger heated by exhaust gas generated by the hot water supply burner 8A. The hot water supply side heat exchanger 7 includes a hot water supply side first heat exchanger 7A and a hot water supply side second heat exchanger 7B. The hot water supply side first heat exchanger 7A has a plurality of fins 7Z. The first combustion system section 5 includes the hot water supply side first heat exchanger 7A above the plurality of hot water supply burners 8A, and the hot water supply side second heat exchanger 7B above the hot water supply side first heat exchanger 7A. A pipe 7C is connected between the downstream end of the hot water supply side second heat exchanger 7B and the upstream end of the hot water supply side first heat exchanger 7A, and hot water that has flowed through the hot water supply side second heat exchanger 7B flows through the pipe 7C to the hot water supply side first heat exchanger 7A. The hot water supply side heat exchanger 7 heats water passing through the inside thereof with exhaust gas (combustion exhaust gas) generated by burning gas with the plurality of hot water supply burners 8A. The hot water supply side first heat exchanger 7A recovers sensible heat from the exhaust combustion gas discharged from the hot water supply side burner unit 8, and the hot water supply side second heat exchanger 7B recovers latent heat from the exhaust combustion gas discharged from the hot water supply side burner unit 8.

[0025] The hot water supply circuit 2 further includes a water supply pipe 11, a control valve 13A, a water volume sensor 14, a hot water outlet pipe 10, a bypass pipe 12, a control valve 13B, a thermistor 15A (hot water supply inner body thermistor), and a thermistor 15B (hot water supply outlet thermistor). The water supply pipe 11 is connected to an inlet of the hot water supply side heat exchanger 7. The water supply pipe 11 is connected to an external piping, and is configured as a pipe that introduces tap water from a waterworks, for example, and flows the tap water toward the upstream end (inlet) of the hot water supply side heat exchanger 7. The water volume sensor 14 is a sensor that detects the flow rate of water flowing through the water supply pipe 11. The control valve 13A is a valve that controls the flow rate of 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 through which hot water heated in the hot water supply side heat exchanger 7 flows. The hot water outlet pipe 10 forms a path through which the hot water heated in the hot water supply side heat exchanger 7 flows outside the appliance.

[0026] 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, and specifically, is configured as a valve for changing the opening degree of the bypass pipe 12 by control.

[0027] A thermistor 15A is provided upstream of the connection of the bypass pipe 12 in the hot water outlet pipe 10. Thermistor 15A detects the temperature of the hot water discharged from the hot water supply side heat exchanger 7, specifically, detects the hot water temperature near the outlet of the hot water supply side first heat exchanger 7A. A thermistor 15B is provided downstream of the connection of the bypass pipe 12. Thermistor 15B detects the temperature of the hot water discharged after mixing with water from the bypass pipe 12, specifically, detects the temperature of the hot water supplied downstream of the junction with 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, which will be described later.

[0028] The hot water supply circuit 2 further includes a gas pipe 16, a main gas solenoid valve 17, a gas proportional valve 18, and a changeover valve 19. The gas pipe 16 is a pipe through which gas supplied from outside the hot water heater 1 via a gas inlet passes, and forms a path for supplying gas to the hot water supply burner 8A. The main gas solenoid valve 17 is provided on the upstream side of the gas pipe 16, and the gas proportional valve 18 is provided on the downstream side of the main gas solenoid valve 17. The gas pipe 16 branches on the downstream side of the gas proportional valve 18 (hot water supply gas proportional valve), and branch pipes 16A to each of the burner blocks 9A, 9B, and 9C and branch pipes 16B to each of the burner blocks 34A and 34B are provided. Each branch pipe 16A is provided with a changeover valve 19 configured as a solenoid valve. The switching valve 19 (hot water supply switching solenoid valve) switches the branch pipe 16A between an open state (supply possible state) and a closed state (shutoff state), and the supply and shutoff of fuel gas to each of the burner blocks 9A, 9B, and 9C is individually switched by each switching valve 19. By switching the switching valve 19, the combustion range of the hot water supply side burner unit 8 is switched, and each combustion range is associated with a stage number.

[0029] The hot water supply circuit 2 further includes a fan 20. The fan 20 includes a rotor 20B that generates wind by its own rotation, and a drive source 20A that rotates the rotor 20B. The fan 20 is provided below the hot water supply combustion chamber 5A, and the operation of the fan 20 supplies air for combustion 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 an exhaust port. The hot water supply circuit 2 is also provided with an igniter for ignition, an ignition electrode, a hot water supply frame rod, and the like.

[0030] The bath circuit 4 comprises a bath circulation path 63 and a bath heat exchanger 50. The bath circulation path 63 is a flow path configured to circulate hot and cold water drawn from an external bathtub 52 and introduce it into the bathtub 52. The bath heat exchanger 50 is configured as a liquid-liquid heat exchanger that exchanges heat between the heat medium flowing through the bath heating piping 51 and the hot and cold water flowing through the bath circulation path 63. The bath heat exchanger 50 functions to heat the hot and cold water flowing through the bath circulation path 63 when the temperature of the heat medium flowing through the bath heating piping 51 is higher than the temperature of the hot and cold water flowing through the bath circulation path 63.

[0031] The bath 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 piping 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 piping 53 is provided with a bath supply thermistor 64 that detects the temperature of the hot and cold water flowing out from the bath heat exchanger 50 to the bathtub 52. The bath return piping 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 piping 54.

[0032] 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.

[0033] The heating circuit 3 is a circuit that can heat a heat medium by the heating side heat exchanger 32 and supply the heat medium to a heating terminal (heat dissipation terminal) via a heat medium circulation path 48. In this embodiment, the heat medium is hot water. The heating circuit 3 includes a second combustion system section 6 and a heat medium circulation path 48. The second combustion system section 6 is provided with a heating combustion chamber 6A, and a heating side burner unit 33 and a heating side heat exchanger 32 are provided in the heating combustion chamber 6A. The heating combustion chamber 6A is partitioned from the hot water supply combustion chamber 5A by a partition member 80 within the accommodation body 1A, and a temperature sensor 82 that detects the temperature of the heating combustion chamber 6A is provided in the partition member 80.

[0034] 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.

[0035] The heating side heat exchanger 32 is a heat exchanger heated by exhaust gas generated by the heating burner 33A, and specifically, is a device that acts to heat the heat medium passing through its interior by the combustion exhaust gas of the heating burner 33A. The heating side heat exchanger 32 includes a heating side first heat exchanger 32A corresponding to the first heat exchanger and a heating side second heat exchanger 32B corresponding to the second heat exchanger. The heating side first heat exchanger 32A has a plurality of fins 32Z. The second combustion system section 6 includes the heating side first heat exchanger 32A provided above the plurality of heating burners 33A, and the heating side second heat exchanger 32B provided above the heating side first heat exchanger 32A. The heating side heat exchanger 32 heats the heat medium passing through its interior by the exhaust gas (combustion exhaust gas) generated by burning gas by the plurality of heating burners 33A. The heating side first heat exchanger 32A recovers sensible heat from the exhaust gas discharged from the heating side burner unit 33, and the heating side second heat exchanger 32B recovers latent heat from the exhaust gas discharged from the heating side burner unit 33.

[0036] The heat medium circulation path 48 is a path for circulating the heat medium through the heating-side heat exchanger 32, and forms a flow path of the heat medium. The heat medium circulation path 48 includes a first internal flow path 38A as a heating high-temperature outgoing piping, a second internal flow path 38B as a heating low-temperature outgoing piping, and a common flow path 38C as a heating return piping.

[0037] 1, when the first heat dissipation terminal 39A is connected as a heating terminal, the heat medium circulation path 48 is configured to circulate the heat medium through the first internal flow path 38A, the first terminal flow path 38G of the first heat dissipation terminal 39A, and the common flow path 38C. When the second heat dissipation terminal 39Z is connected as a heating terminal, the heat medium circulation path 48 is configured to circulate the heat medium through the second internal flow path 38B, the second terminal flow path 38H of the second heat dissipation terminal 39Z, and the common flow path 38C.

[0038] The heating circuit 3 further includes an expansion tank 36 corresponding to an example of a tank, a heating circulation pump 37 corresponding to an example of a pump, a heating high-temperature thermistor 40, and a heating low-temperature thermistor 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 that flows the heat medium discharged from the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z so as to pass through the heating side heat exchanger 32 (heating side second heat exchanger 32B). The common flow path 38C is configured to communicate with the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and is connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z outside the appliance. Between the outlet of the heating side second heat exchanger 32B and the inlet of the heating side first heat exchanger 32A, there is an intermediate pipe 38D which is part of the common flow path 38C, and an intermediate pipe 38E which is part of the common flow path 38C and the first internal flow path 38A, and an expansion tank 36 and a heating circulation pump 37 are provided in the path of the intermediate pipes 38D, 38E. The intermediate pipe 38D is provided between the outlet of the heating side second 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 heating side first heat exchanger 32A. The heating circulation pump 37 is provided in the middle of the intermediate pipe 38E.

[0039] The second internal flow path 38B is provided in a configuration in which a plurality of internal branch paths 38F are branched. Each internal branch path 38F is provided with a second valve 39G 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 side 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 fan that blows hot air into a bathroom or a dressing room. The second heat dissipation terminal 39Z is, for example, a low-temperature heating terminal such as a floor heater in a dressing room.

[0040] The heating high temperature thermistor 40 is provided in the first internal flow path 38A on the outlet side of the heating side heat exchanger 32, and detects the temperature of the heat medium flowing out from the heating side heat exchanger 32 (specifically, the heat medium flowing out from the heating side first heat exchanger 32A). The temperature detected by the heating high temperature thermistor 40 corresponds to the temperature of the heat medium flowing into the first heat dissipation terminal 39A when the heat medium circulates through the first heat dissipation terminal 39A. The heating low temperature thermistor 41 is provided in the expansion tank 36. The temperature detected by the heating low temperature thermistor 41 corresponds to the temperature of the heat medium flowing into the second heat dissipation terminal 39Z when the heat medium circulates through the second heat dissipation terminal 39Z.

[0041] The heating circuit 3 includes a plurality of branch pipes 16B and a plurality of heating switching solenoid valves 44. As described above, the branch pipes 16B are provided in a configuration in which they branch off from the gas pipe 16 to the heating circuit 3 side. Each heating switching solenoid valve 44 is provided in each branch pipe 16B. The heating switching solenoid valve 44 is configured to switch the branch pipe 16B to which it is provided between an open state (supply possible state) and a closed state (cut-off state). The supply and cut-off of fuel gas to each of the burner blocks 34A, 34B is individually switched by each heating switching solenoid valve 44. The combustion range of the heating side burner unit 33 is switched by switching the heating switching solenoid valve 44, and each combustion range is associated with a stage number. The heating circuit 3 is also provided with an ignition electrode, a heating flame rod, and the like.

[0042] In the heating circuit 3, the hot water heated in the heating side heat exchanger 32 circulates through the heat medium circulation path 48 by the operation of the heating circulation pump 37. 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 in the heating side heat exchanger 32 by the combustion exhaust gas discharged from the heating side burner unit 33, 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 in response to the operation of the first valve 39H, which is a built-in thermal 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 in response to the operation of the second valve 39G, which is a thermal valve in the appliance.

[0043] As shown in Fig. 1, a bath heating pipe 51 is provided branching off from the first internal flow path 38A. The bath heating pipe 51 branches off from a position downstream of the heating side heat exchanger 32 in the heat medium circulation path 48 (specifically, downstream of the heating side first heat exchanger 32A) and forms a flow path that guides the heat medium that has flowed through the heat medium circulation path 48 to the bath heat exchanger 50. 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 of them.

[0044] The control valve 58 is a valve provided in the bath heating pipe 51 upstream of the bath heat exchanger 50. 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 control valve 58 blocks water passing through the bath heating pipe 51, and an open state in which the control valve 58 allows water to pass through the bath heating pipe 51. 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, it goes into a first state in which it outputs a predetermined first signal (e.g., an on signal), and when the control valve 58 is in the fully closed state in which it is blocked, it goes into a second state in which it outputs a second signal (e.g., an off signal) different from the first signal.

[0045] The hot water heater 1 further comprises a control device 70, a hot water remote control 71, a bath remote control 72, and a room temperature thermistor (not shown). The control device 70 corresponds to an example of a control unit, and is an electronic control device equipped with 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 that performs various controls. The memory stores various programs, data tables, setting values, etc. The control device 70 is configured to be able to acquire signals from each sensor and switch (thermistor, water volume sensor, switch, etc.), and controls the hot water supply circuit 2, heating circuit 3, bath circuit 4, etc. The room temperature thermistor is provided, for example, in a changing room as air temperature detection means that detects the temperature in the changing room.

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

[0047] During the above-mentioned hot water discharging operation, the control device 70 monitors the outlet hot water temperature detected by thermistor 15B installed in the hot water discharge pipe 10, and controls the opening and closing of the switching valve 19 and adjusts the opening of the gas proportional valve 18 so that the outlet hot water temperature becomes the set temperature instructed by the hot water remote control 71 or the bath remote control 72, while continuously changing the amount of air by controlling the rotation speed of the fan 20. If the above-mentioned hot water tap is closed during the above-mentioned hot water discharging operation and the signal output by the water volume sensor 14 indicates a water stop state, the control device 70 closes the main gas solenoid valve 17 and the switching valve 19 to extinguish the hot water supply burner 8A, and rotates the fan 20 for a predetermined time to perform post-purge.

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

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

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

[0051] 3. Structure for removing air from heat transfer medium In a hot water supply and heating system that configures a circulation circuit for the first heat dissipation terminal 39A (high-temperature heating terminal) and the second heat dissipation terminal 39Z (low-temperature heating terminal), it is known that when the first heat dissipation terminal 39A or the second heat dissipation terminal 39Z is installed higher than the cistern serving as the expansion tank 36 in the circulation circuit, the water in the piping gradually moves toward the heat dissipation terminal side along with the movement of air mixed with the hot water. If this state is left for a long time, the water in the heat dissipation terminal and the piping may flow into the expansion tank 36 side and overflow. In light of this, it is required to remove air from the heat medium flowing in the hot water supply and heating device 1, and a configuration is provided to remove air from the heat medium flowing in the hot water supply and heating device 1.

[0052] In the heat medium circulation path 48, the common flow path 38C is a flow path from the inlet portion 35A to the branch portion 38J, and the heating side second heat exchanger 32B, the expansion tank 36, and the heating circulation pump 37 are provided in the middle of the common flow path 38C. The common flow path 38C guides the heat medium so that the heat medium flows from the inlet portion 35A to the inlet of the expansion tank 36 and from the outlet of the expansion tank 36 to the branch portion 38J when the heating circulation pump 37 is in operation. The upstream end of the common flow path 38C is the inlet portion 35A that is configured to be connectable to the outside and into which the heat medium flows, and the downstream end is the branch portion 38J. The downstream side of the branch portion 38J is branched into the first internal flow path 38A and the second internal flow path 38B.

[0053] The first internal flow path 38A is a flow path from the branching portion 38J to the first outflow portion 35B. The upstream end of the first internal flow path 38A is the branching portion 38J, and the downstream end is the first outflow portion 35B that is configured to be connectable to the outside and through which the heat medium flows out. The heating side first heat exchanger 32A is provided midway along the first internal flow path 38A. The first internal flow path 38A guides the heat medium to flow from the branching portion 38J to the first outflow portion 35B when the first valve 39H is open and the heating circulation pump 37 is operating.

[0054] The second internal flow path 38B is a flow path from the branching portion 38J to each second outlet portion 35C. The upstream end of the second internal flow path 38B is the branching portion 38J, and the downstream end is the second outlet portion 35C that is configured to be connectable to the outside and that allows the heat medium to flow out. When any of the second valves 39G is open and the heating circulation pump 37 is operating, the second internal flow path 38B guides the heat medium to flow from the branching portion 38J to the second outlet portion 35C in the path of the open second valve 39G.

[0055] A first heat dissipation terminal 39A and a second heat dissipation terminal 39Z are provided outside the hot water heater 1, to which the heat medium is supplied from the hot water heater 1 and which communicate with the heat medium circulation path 48. The first heat dissipation terminal 39A is a heating terminal having a first terminal flow path 38G through which the heat medium flows and configured to dissipate heat of the heat medium flowing through the first terminal flow path 38G. The second heat dissipation terminal 39Z is a heating terminal having a second terminal flow path 38H through which the heat medium flows and configured to dissipate heat of the heat medium flowing through the second terminal flow path 38H. The downstream end of the first terminal flow path 38G and the downstream end of the second terminal flow path 38H are connectable to communicate with the inlet portion 35A of the hot water heater 1. The inlet portion 35A is an inlet into which the heat medium flowing through the first terminal flow path 38G and the heat medium flowing through the second terminal flow path 38H flow. The first outlet portion 35B is 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 outlet portion 35C is an outlet through which the heat medium flows out from the second internal flow path 38B to the second terminal flow path 38H.

[0056] The first valve 39H switches between a state in which the supply of heat medium to the first internal flow path 38A and the first terminal flow path 38G downstream of the first valve 39H is blocked and a state in which the supply of heat medium is permitted. When the first valve 39H is open, the flow of heat medium from the first internal flow path 38A to the first terminal flow path 38G and the flow of heat medium from the first terminal flow path 38G to the common flow path 38C are permitted. When the first valve 39H is closed, the movement of heat medium from the upstream side of the first valve 39H through the first valve 39H to the downstream side is blocked, and the flow of heat medium from the first internal flow path 38A to the first terminal flow path 38G is blocked.

[0057] The second valve 39G switches between a state in which the supply of heat medium to the second internal flow path 38B and the second terminal flow path 38H downstream of the second valve 39G is blocked and a state in which the supply of heat medium to the second internal flow path 38B and the second terminal flow path 38H downstream of the second valve 39G is permitted when any of the second valves 39G is open, the flow of heat medium from the second internal flow path 38B to the second terminal flow path 38H present downstream of the open second valve 39G, and the flow of heat medium from the second terminal flow path 38H to the common flow path 38C are permitted. When any of the second valves 39G is closed, the movement of heat medium from the upstream side of the closed second valve 39G to the downstream side through the second valve 39G is blocked, and the flow of heat medium from the second internal flow path 38B to the second terminal flow path 38H downstream of the closed second valve 39G is blocked.

[0058] The first valve 39H and the plurality of second valves 39G are all thermal valves. When an open command is issued (for example, when the power supply of the thermal valve is turned on), the thermal valve expands an expansion body with the heat of a heating element (positive temperature coefficient) to push a piston and open the valve, allowing hot and cold water to flow through the thermal valve, and when an open command is issued (for example, when the power supply of the thermal valve is turned off), the heating element naturally releases heat, contracting the expansion body and closing the valve, preventing hot and cold water from flowing through the thermal valve. Due to its structure, the thermal valve operates slowly when opening and closing the valve, and does not immediately reach a fully open or fully closed state even when turned on and off, so that the adoption of the thermal valve makes it difficult for the water hammer phenomenon to occur.

[0059] The heat medium that has flowed into the inlet 35A is configured to circulate through the heat medium circulation path 48 in the hot water heater 1. For example, when the heating circulation pump 37 operates with either the first valve 39H or the second valve 39G open, the heating circulation pump 37 causes the heat medium to flow from the expansion tank 36 side to the branching part 38J side, so that the heat medium that has flowed into the inlet 35A flows from the inlet 35 to the common flow path 38C, and in the common flow path 38C, the heat medium flows from the inlet 35A to the branching part 38J. When the heat medium flows through the common flow path 38C in this way, if the heating burner 33A is burning, the heat medium flowing through the common flow path 38C is heated in the heating-side second heat exchanger 32B in the middle of the common flow path 38C, and then flows through the expansion tank 36 and the heating circulation pump 37 to the branching part 38J.

[0060] When the heating circulation pump 37 is operating with either the first valve 39H or the second valve 39G open as described above, the heat medium that has flowed into the branching portion 38J flows into at least one of the first internal flow path 38A and the second internal flow path 38B. For example, when the first valve 39H is open and the flow of the heat medium from the first internal flow path 38A to the first terminal flow path 38G is permitted, at least a part of the heat medium that has flowed into the branching portion 38J flows into the first internal flow path 38A, and the heat medium flows from the branching portion 38J to the first outlet portion 35B in the first internal flow path 38A. When the heat medium flows through the first internal flow path 38A in this way, if the heating burner 33A is burning, the heat medium flowing through the first internal flow path 38A is heated by the heating-side first heat exchanger 32A on the way. The heat medium that has flowed through first internal flow path 38A is discharged from first outlet portion 35B toward first terminal flow path 38G, and the heat medium that has passed through first terminal flow path 38G flows into inlet portion 35A. In this manner, when first valve 39H is open, a path through which the heat medium can circulate is formed by common flow path 38C, first internal flow path 38A, and first terminal flow path 38G, and the heat medium flows so as to circulate through this path.

[0061] In addition, when any of the second valves 39G is open and the flow of the heat medium from the second internal flow path 38B to the second terminal flow path 38H is permitted, at least a part of the heat medium that has flowed into the branching portion 38J flows into the second internal flow path 38B, and the heat medium flows from the branching portion 38J to the second outlet portion 35C in the second internal flow path 38B. The heat medium that has flowed through the second internal flow path 38B is discharged toward the second terminal flow path 38H from the second outlet portion 35C as an outlet, and the heat medium that has passed through the second terminal flow path 38H flows into the inlet portion 35A. In this way, when the second valve 39G is open, a path through which the heat medium can circulate is formed by the common flow path 38C, the second internal flow path 38B, and the second terminal flow path 38H, and the heat medium flows so as to circulate through this path.

[0062] When the heating circulation pump 37 is operating with both the first valve 39H and the second valve 39G open, the heat medium that flows into the branching portion 38J is separated into a heat medium heading toward the first internal flow path 38A and a heat medium heading toward the second internal flow path 38B, and flows in each flow path.

[0063] The first valve 39H that opens and closes the first terminal flow path 38G, the second valve 39G that opens and closes the second internal flow path 38B, and the heating circulation pump 37 are controlled by the control device 70. The control device 70 is electrically connected to the second valve 39G and the heating circulation pump 37 so as to be controllable, and performs opening and closing control of the second valve 39G and driving control of the heating circulation pump 37. For example, when the second valve 39G is in a closed state and an open command is given from the control device 70 to the second valve 39G, the second valve 39G switches from a closed state to an open state, and when the second valve 39G is in an open state and a closing command is given from the control device 70 to the second valve 39G, the second valve 39G switches from an open state to a closed state. The control device 70 can directly or indirectly perform opening and closing control of the first valve 39H. For example, the control device 70 may be configured to give an instruction to control the first valve 39H by communication to a control unit (not shown) provided in the first heat dissipation terminal 39A. In this case, when the control device 70 gives information (open instruction) to the control unit instructing the first valve 39H to be opened, the control unit may control the first valve 39H to be switched to an open state, and when the control device 70 gives information (close instruction) to the control unit instructing the first valve 39H to be closed, the control unit may control the first valve 39H to be switched to a closed state. Alternatively, the control device 70 may directly give an instruction to the first valve 39H. For example, the control device 70 may directly control the first valve 39H so that when the first valve 39H is in a closed state and an open command is given from the control device 70 to the first valve 39H, the first valve 39H switches from a closed state to an open state, and when the first valve 39H is in an open state and a closing command is given from the control device 70 to the first valve 39H, the first valve 39H switches from an open state to a closed state.

[0064] 4. Operation of the control device 70 to remove air from the heat transfer medium The control device 70 executes the control (removal control) shown in FIG. 2 when a predetermined start condition is satisfied. The predetermined start condition may be, for example, that the control device 70 is powered on, that a predetermined operation is performed in the hot water heater 1, that the previous air removal process is completed, that any of these conditions is satisfied, or other conditions. The control device 70 continuously counts how much time has passed since the previous air removal process was completed. The count of "how much time has passed" may be a measurement of "time" that has passed since the previous air removal process was completed, or a count of "days" that have passed since the previous air removal process, or a count of "number of times" that the heating circuit 3 has operated since the previous air removal process was completed. The end point of the previous air removal process is the end point of the removal control of FIG. 2 that was most recently performed in the hot water heater 1 in the past.

[0065] 2, when the control device 70 determines that a predetermined time has elapsed since the end of the previous air removal process at the time of execution of step S1 (if Yes in step S1), the control device 70 advances the process to step S2, and when the control device 70 determines that the predetermined time has not elapsed since the end of the previous air removal process (if No in step S1), the control device 70 repeats the determination of step S1. The case where a predetermined time has elapsed since the end of the previous air removal process may be a case where a predetermined fixed time (e.g., 240 hours) has elapsed since the end of the previous air removal process, a case where a predetermined fixed number of days (e.g., 30 days) has elapsed since the end of the previous air removal process, or a case where the heating circuit 3 has been operated a predetermined fixed number of times since the end of the previous air removal process.

[0066] When the control device 70 determines in step S1 that "a predetermined time has elapsed since the end of the previous air removal process," the control device 70 performs a first process in step S2.

[0067] (First process) When the control device 70 starts the first process in step S2, it outputs a first open signal for opening the first valve 39H, which is a thermal valve on the high temperature side, a second close signal for closing the second valve 39G, which is a thermal valve on the low temperature side, and a drive signal for operating the heating circulation pump 37 (S2). In this example, the first open signal is a control signal for opening one of the first valve 39H and the second valve 39G. The second close signal is a control signal for closing the other of the first valve 39H and the second valve 39G. In this way, the control device 70 starts the first process so as to operate the heating circulation pump 37 while opening one of the first valve 39H and the second valve 39G and closing the other valve. When the first process is performed, the heat medium in the first internal flow path 38A and the first terminal flow path 38G flows so as to circulate, and air is removed from the heat medium in the first internal flow path 38A and the first terminal flow path 38G in the process of passing through the expansion tank 36. During the first process, the circulation of the heat medium in the second internal flow path 38B and the second terminal flow path 38H stops.

[0068] After step S2, the control device 70 determines whether a predetermined certain time (T1 time) has elapsed since the start of the first process in step S3 (S3). The T1 time is, for example, a time during which air in the first internal flow path 38A and the first terminal flow path 38G is assumed to be sufficiently removed, and is stored in advance in the memory of the control device 70. The T1 time may be, for example, a time longer than the time required for the first valve 39H to open to its maximum opening degree (maximum opening degree in the first process) after the control device 70 starts outputting the first open signal and starts control to open the first valve 39H.

[0069] After step S2, the control device 70 repeats the determination in step S3 (determination of No in step S3) until it determines that "T1 time has elapsed since the first process was started in step S2." If the control device 70 determines in step S3 that "a predetermined fixed time (T1 time) has elapsed since the first process was started in step S2," the control device 70 advances the process to step S4, ends the first process, and starts the second process. Note that the control device 70 continues the above-mentioned first process (process of operating the heating circulation pump 37 while keeping one of the first valve 39H and the second valve 39G open and the other valve closed) until it determines in step S3 that "T1 time has elapsed since the first process was started in step S2."

[0070] (Second Processing) When the control device 70 advances the process to step S4 to start the second process, it outputs a first close signal for closing the first valve 39H, a second close signal for closing the second valve 39G, and a stop signal for stopping the heating circulation pump 37 (S4). In this way, after the first process, the control device 70 performs the second process to stop the operation of the heating circulation pump 37 and to close the first valve 39H and the second valve 39G.

[0071] After starting the second process in step S4, the control device 70 judges in step S5 whether a predetermined certain time (T2 time) has elapsed since starting the second process in step S4 (S5). The T2 time corresponds to an example of the first time. The thermal valves used as the first valve 39H and the second valve 39G take time to start operating from an open state to a closed state. The T2 time may be longer than the time required for the one valve to be completely closed after the control device 70 starts controlling the one valve to close so as to give a closing signal (close signal) to the one valve that was open in the first process. In this embodiment, the T2 time is pre-stored in the memory of the control device 70. Since such control is performed, in the second process, after outputting a signal to close one of the valves (first valve 39H) that was opened in the first process with the start of step S4, the one of the valves (first valve 39H) operates to gradually close, and the flow of the heat medium in the first internal flow path 38A and the first terminal flow path 38G gradually decreases with this operation. Then, when the time T2 has elapsed since the start of the second process in step S4, the first valve 39H is in a completely closed state, and the second valve 39G is in a completely closed state until the time T2 has elapsed since the start of the second process in step S4. Therefore, when the control device 70 judges Yes in step S5, the circulation of the heat medium has stopped in the first internal flow path 38A and the first terminal flow path 38G, and the circulation of the heat medium has also stopped in the second internal flow path 38B and the second terminal flow path 38H.

[0072] If the control device 70 determines in step S5 that "a predetermined fixed time (T2 time) has elapsed since the start of the second process" (if "Yes" in S5), the control device 70 advances the process to step S6 to end the second process and start the third process. After starting the second process in step S4, the control device 70 continues to stop the heating circulation pump 37 while instructing both the first valve 39H and the second valve 39G to be closed until it determines in step S5 that "a predetermined fixed time (T2 time) has elapsed since the start of the second process."

[0073] At the time when it is determined in step S5 that "a predetermined certain time (T2 time) has elapsed since the start of the second process", the first valve 39H is in a completely closed state, and the second valve 39G is also in a completely closed state. Therefore, at the time when the third process is started in step S6, the circulation of the heat medium is stopped in the first internal flow path 38A and the first terminal flow path 38G, and the circulation of the heat medium is also stopped in the second internal flow path 38B and the second terminal flow path 38H. The control device 70 starts the third process in this state in step S6. That is, the control device 70 uses the period of the second process to switch one valve from an open state to a completely closed state, while maintaining the other valve in a completely closed state throughout the entire period of the second process, and starts the third process after the one valve and the other valve are completely closed during the period of the second process.

[0074] (Third Processing) When the control device 70 starts the third process in step S6, it outputs a first close signal for closing the first valve 39H, a second open signal for opening the second valve 39G, and a drive signal for operating the heating circulation pump 37 (S6). In this example, the first close signal is a control signal for closing one of the first valve 39H and the second valve 39G. The second open signal is a control signal for opening the other of the first valve 39H and the second valve 39G. In this way, after the first process and the second process, the control device 70 starts the third process so as to operate the heating circulation pump 37 while keeping one of the first valve 39H and the second valve 39G in a closed state and the other in an open state. When the third process is performed, the heat medium in the second internal flow path 38B and the second terminal flow path 38H flows so as to circulate, and air is removed from the heat medium in the second internal flow path 38B and the second terminal flow path 38H in the process of passing through the expansion tank 36. During the third process, the circulation of the heat medium in the first internal flow path 38A and the first terminal flow path 38G stops.

[0075] After step S6, the control device 70 determines whether a predetermined certain time (T3 time) has elapsed since the start of the third process in step S7 (S7). The T3 time is, for example, a time during which air in the second internal flow path 38B and the second terminal flow path 38H is assumed to be sufficiently removed, and is stored in advance in the memory of the control device 70. The T3 time may be, for example, a time longer than the time required for the second valve 39G to open to its maximum opening degree (maximum opening degree in the third process) after the control device 70 starts outputting the second open signal and starts control to open the second valve 39G.

[0076] After step S6, the control device 70 repeats the determination of step S7 (determination of No in step S7) until it determines in step S7 that "T3 time has elapsed since the start of the third process in step S6." If the control device 70 determines in step S7 that "a predetermined fixed time (T3 time) has elapsed since the start of the third process in step S6," the control device 70 advances the process to step S8 and ends the third process. Note that the control device 70 continues the above-mentioned third process (a process of operating the heating circulation pump 37 while keeping one of the first valve 39H and the second valve 39G in a closed state and the other in an open state) from the start of the third process in step S6 until it determines in step S7 that "T3 time has elapsed since the start of the third process in step S6."

[0077] When the process proceeds to step S8, the control device 70 outputs a first close signal for closing the first valve 39H, a second close signal for closing the second valve 39G, and a stop signal for stopping the heating circulation pump 37 (S8). In this way, after the third process ends, the control device 70 closes both of the one valve and the other valve, and stops the operation of the heating circulation pump 37. This ends the removal control (process for removing air) in FIG. 2.

[0078] In the above-mentioned representative example, when the first valve 39H and the second valve 39G are closed, a signal is output from the control device 70 to maintain them in the closed state. However, if the first valve 39H and the second valve 39G are "configured to be maintained in the closed state when no signal is given", the first valve 39H and the second valve 39G may be maintained in the closed state by not outputting a signal to them.

[0079] 5. Example of effects In the hot water heater 1, the heat medium in the common flow path 38C can be branched into the first internal flow path 38A and the second internal flow path 38B from the branching part 38J provided at the downstream end of the common flow path 38C. The first heat exchanger is capable of heating the heat medium flowing through the first internal flow path 38A, and the first outlet part 35B is provided at the downstream end of the first internal flow path 38A, and the heat medium flowing out from the first outlet part 35B can flow to the inlet part 35A through the first terminal flow path 38G in the first heat dissipation terminal. The second outlet part 35C is provided at the downstream end of the second internal flow path 38B, and the heat medium flowing out from the second outlet part 35C can flow to the inlet part 35A through the second terminal flow path 38H in the second heat dissipation terminal. Due to this configuration, a circulation path in which the heat medium circulates through the common flow path 38C, the first internal flow path 38A, and the first terminal flow path 38G, and a circulation path in which the heat medium circulates through the common flow path 38C, the second internal flow path 38B, and the second terminal flow path 38H are configured. In this configuration, the heat medium that flows from the branching portion 38J to the first internal flow path 38A and the second internal flow path 38B passes through the first terminal flow path 38G in the first heat dissipation terminal 39A and the second terminal flow path 38H in the second heat dissipation terminal 39Z, respectively, and merges on the inlet 35A side. In this configuration, there is a concern that air in one flow path may be mixed into the flow path on the other side at the part where the flow path on the first heat dissipation terminal 39A side and the flow path on the second heat dissipation terminal 39Z side merge on the inlet 35A side.

[0080] Regarding this problem, in the first process, the hot water heater 1 operates the heating circulation pump 37 while opening one of the first valve 39H and the second valve 39G and closing the other valve. That is, in the first process, the heat medium is caused to flow in a circulation path including the common flow path 38C, one of the internal flow paths, and one of the terminal flow paths, and air is removed so as to remove air contained in the heat medium. Then, since the other valve is closed during the first process, the flow of the heat medium is suppressed in the other internal flow path and the other terminal flow path, and the intrusion of air into the other internal flow path and the other terminal flow path is suppressed. Furthermore, after the first process, the hot water heater performs a third process, and operates the heating circulation pump 37 while opening the other of the first valve 39H and the second valve 39G and closing the other valve. That is, in the third process, the heat medium is caused to flow in a circulation path including the common flow path 38C, the other internal flow path, and the other terminal flow path, and air is removed from the heat medium. In the third process, one valve is closed, so that the flow of the heat medium is suppressed in the one internal flow path and the one terminal flow path, and the intrusion of air into the one internal flow path and the one terminal flow path is suppressed.

[0081] In this way, the hot water heater 1 can perform both the air bleed from the first internal flow path 38A and the first terminal flow path 38G and the air bleed from the second internal flow path 38B and the second terminal flow path 38H, and when air is bled from one path, it can reliably prevent air from being mixed into the other path. Furthermore, the hot water heater 1 performs the second process of stopping the operation of the heating circulation pump 37 for a first time after the first process and before the third process, so that it is possible to secure time that can be used for switching control of the first valve 39H and the second valve 39G after the first process and before the third process. Therefore, the hot water heater 1 can easily prevent an unstable state of the third process caused by a lack of time from the end of the first process to the start of the third process (an unstable state caused by the switching of the first valve 39H and the second valve 39G not being reliably completed, etc.).

[0082] <Other embodiments> The present invention is not limited to the embodiments described above and in the drawings. For example, the features of the above or later described embodiments can be combined in any combination within a range that does not contradict. Furthermore, any feature of the above or later described embodiments can be omitted unless it is clearly stated as essential. Furthermore, the above described embodiments may be modified as follows.

[0083] In the above embodiment, when the removal control of Fig. 2 is performed, the control device 70 can perform the removal control of Fig. 2 so as to maintain the heating burner 33A in a non-ignited state (non-combustion state) at least from the start of step S2 to the end of step S8. That is, the control device 70 can maintain the heating burner 33A in a non-ignited state (non-combustion state) during any of the above-mentioned first process, second process, and third process. However, without being limited to this example, the removal control of Fig. 2 may be performed during the period when the heating burner 33A is ignited, or the heating burner 33A may be ignited during a part of the period from the start of step S2 to the end of step S8 in Fig. 2.

[0084] In the above embodiment, the hot water heater 1 removes air from the first internal flow path 38A and the first terminal flow path 38G, which are the high temperature side, in the first process, and then removes air from the second internal flow path 38B and the second terminal flow path 38H, which are the low temperature side, in the third process, in order to remove air from the heat medium in the heat medium circulation path 48, but is not limited to this example. For example, the hot water heater 1 may operate in the first process by closing the first valve 39H, opening the second valve 39G, and operating the heating circulation pump 37 to remove air from the second internal flow path 38B and the second terminal flow path 38H, which are the low temperature side, and then in the third process by opening the first valve 39H, opening the second valve 39G, and operating the heating circulation pump 37 to remove air from the first internal flow path 38A and the first terminal flow path 38G, which are the high temperature side.

[0085] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0086] 1: Hot water heater 1A: Containment Unit 2: Hot water circuit 3: Heating circuit 4: Bath circuit 5A: Hot water combustion chamber 6A: Heating combustion chamber 7: Hot water heat exchanger 7Z: Fin 8: Hot water supply burner unit 8A: Hot water burner 9A: Burner block 9B: Burner block 9C: Burner block 10: Tap pipe 11: Water supply pipe 20: Fan 20A: Driving source 20B: Rotating body 32: Heating side heat exchanger 32: Heating side first heat exchanger (first heat exchanger) 32: Heating side second heat exchanger (second heat exchanger) 33: Heating side burner unit 33A: Heating burner 34A: Burner block 34B: Burner block 35A: Inflow section 35B: 1st outlet 35C: 2nd outlet 36: Expansion tank (tank) 37: Heating circulation pump (pump) 38A: First internal flow passage 38B: Second internal flow passage 38C: Common flow path 38J: Branch 39A: First heat dissipation terminal 39Z: Second heat dissipation terminal 38G: First terminal channel 38B: Second terminal flow path 39H: First valve 39G: Second valve 48: Heat medium circulation path 70: Control device (control unit) 80: Partition material 82: Temperature sensor

Claims

1. The heat medium is supplied to a first heat dissipation terminal having a first terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the first terminal flow path, and a second heat dissipation terminal having a second terminal flow path through which the heat medium flows and dissipating heat from the heat medium flowing through the second terminal flow path; A hot water heater that controls a first valve that switches between a state in which the supply of the heat medium to the first terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is blocked and a state in which the supply of the heat medium to the second terminal flow path is permitted, an inlet portion that is provided downstream of the first terminal flow path and downstream of the second terminal flow path and that is an inlet into which the heat medium that has flowed through the first terminal flow path and the heat medium that has flowed through the second terminal flow path flow; a common flow path for passing the heat transfer medium that has flowed into the inlet portion; a branching portion provided at an end of the common flow path and branching the flow of the heat medium that has flowed through the common flow path; A first internal flow path is configured as a flow path branched from the branching portion and is a flow path that flows the heat medium to the first heat dissipation terminal; A second internal flow path that is configured as a flow path branched from the branching portion and that is a flow path that flows the heat medium to the second heat dissipation terminal; A first outlet portion is provided at a downstream end of the first internal flow path and serves as an outlet for discharging the heat medium toward the first terminal flow path; A second outlet portion is provided at an end portion on a downstream side of the second internal flow path and serves as an outlet for discharging the heat medium toward the second terminal flow path; A pump for causing the heat medium to flow in the common flow path; a tank provided in the common flow path and through which the heat medium flows through the common flow path; a first heat exchanger that heats the heat medium flowing through the first internal flow path; a control unit that controls the first valve, the second valve, and the pump; Equipped with The control unit performs a first process of operating the pump while keeping one of the first valve and the second valve in an open state and the other valve in a closed state, performs a second process of stopping the operation of the pump for a first time after the first process, and performs a third process of operating the pump while keeping the one valve in a closed state and the other valve in an open state after the first process and the second process. Hot water heater.

2. the first valve is a first thermal valve; the second valve is a second thermal valve; The control unit controls the one valve to be in a closed state during the second process after the first process, and starts the third process after the one valve is switched to the closed state during the second process. The hot water heater according to claim 1.

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