Hot water supply heater

Abstract

To provide a technology capable of suppressing the residual of a heat medium in a flow path when removing the heat medium.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 device 70 controls a bypass on-off valve 47 to an open state when the first valve 39H is closed and the second valve 39G is open during heating operation, and controls the bypass on-off valve 47 to an open state and a replenishment on-off valve 43 to a closed state when a first operation unit 73 performs setting to remove the heat medium during stop of the heating operation.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 combined heat source machine. This combined heat source machine includes a hot water supply circuit, a heating circuit, a reheating circuit, and a controller. The heating circuit includes an expansion tank, a heating heat exchanger, and a heating circulation pump, which are connected by piping. The hot water in the expansion tank is sent by the heating circulation pump to the downstream heating heat exchanger, where it is heated. The downstream side of the heating heat exchanger branches into a first high-temperature bypass path on the reheating circuit side and a second high-temperature bypass path on the high-temperature water supply port side, and the hot water that passes through these paths is configured to return to the expansion tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2006-46858A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in an apparatus equipped with this type of hot water supply circuit, if the water supply in the apparatus is stopped for a certain period of time in an environment where the ambient temperature is low, such as in winter, there is a risk that the water remaining in the apparatus will freeze. If the water remaining in the apparatus freezes in this way, problems due to freezing will occur, such as damage to the internal piping, etc., and problems in which automatic combustion control triggered by water supply detection will no longer be possible. Therefore, in this type of hot water supply apparatus, one method for dealing with such problems is, for example, to drain the water serving as a heat transfer medium inside the apparatus before stopping the water supply in the apparatus, thereby discharging the water to the outside.

[0005] Here, when draining the water, for example, due to a difference in elevation (depression, etc.) occurring in part of the pipe circulating from the expansion tank, water may remain in the pipe inside the device after it is discharged to the outside. In particular, when the piping route through the heat exchanger is complicated, there are many connections and branching points of the pipes, which is likely to cause differences in elevation, and there is a problem that the water may not be completely removed and may remain when draining the water.

[0006] One object of the present disclosure is to provide a technique for suppressing the heat medium from remaining in the flow path when the heat medium is removed. [Means for solving the problem]

[0007] The hot water heater according to the present disclosure includes: 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 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, A tank for storing the heat transfer medium; A gas burner for burning gas; a first heat exchanger to which combustion exhaust gas generated by combustion of the gas burner is supplied and which heats the heat transfer medium; an inlet portion provided downstream of the first terminal flow path and downstream of the second terminal flow path, the inlet portion being an inlet into which the heat medium flowing through the first terminal flow path flows and an inlet into which the heat medium flowing through the second terminal flow path flows; a common return flow path through which the heat transfer medium that has flowed into the inlet returns to the tank; a common inflow flow path which is a flow path for flowing the heat transfer medium flowing out of the tank; A branching portion that branches the flow of the heat medium that has flowed through the common inflow flow path; a pump provided in the common forward flow passage for causing the heat medium to flow; a first internal flow path that is configured as a flow path branched from the branching portion, a portion of which is heated by the first heat exchanger, and which 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 bypass flow path that is a path for bypassing the heat medium between the common return flow path and the first internal flow path; a refilling passage for refilling the tank with the heat medium from outside the tank; a bypass on-off valve that switches between a suppression state in which the flow of the heat medium in the bypass flow passage is suppressed and a state in which the suppression state is released; a replenishment on-off valve that switches between a blocking state in which the flow of the heat medium is blocked in the replenishment flow path and a state in which the blocking state is released; a control unit that controls the first valve, the second valve, the bypass on-off valve, and the replenishment on-off valve; an operation unit that enables an auxiliary setting operation by an operator and switches to a first setting state when the auxiliary setting operation is performed; Equipped with The control unit is During a heating operation in which the heated heat medium is supplied to at least one of the first heat dissipation terminal and the second heat dissipation terminal, when the first valve is closed and the second valve is opened, the bypass opening / closing valve is controlled to be open; When the heating operation is stopped, if the operation unit is in the first setting state, the bypass on-off valve is controlled to be in an open state, and the supplement on-off valve is controlled to be in a closed state. Effect of the Invention

[0008] According to the technique of the present disclosure, it is possible to suppress the heat medium from remaining in the flow path when the heat medium flowing inside the hot water heater is removed. [Brief description of the drawings]

[0009] [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 the process during water drainage. [Diagram 3] FIG. 3 is a flowchart showing the process during the freeze prevention operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Each of the following [1] to [5] 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, A tank for storing the heat transfer medium; A gas burner for burning gas; a first heat exchanger to which combustion exhaust gas generated by combustion of the gas burner is supplied and which heats the heat transfer medium; an inlet portion provided downstream of the first terminal flow path and downstream of the second terminal flow path, the inlet portion being an inlet into which the heat medium flowing through the first terminal flow path flows and an inlet into which the heat medium flowing through the second terminal flow path flows; a common return flow path through which the heat transfer medium that has flowed into the inlet returns to the tank; a common inflow flow path which is a flow path for flowing the heat transfer medium flowing out of the tank; A branching portion that branches the flow of the heat medium that has flowed through the common inflow flow path; a pump provided in the common forward flow passage for causing the heat medium to flow; a first internal flow path that is configured as a flow path branched from the branching portion, a portion of which is heated by the first heat exchanger, and which 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 bypass flow path that is a path for bypassing the heat medium between the common return flow path and the first internal flow path; a refilling passage for refilling the tank with the heat medium from outside the tank; a bypass on-off valve that switches between a suppression state in which the flow of the heat medium in the bypass flow passage is suppressed and a state in which the suppression state is released; a replenishment on-off valve that switches between a blocking state in which the flow of the heat medium is blocked in the replenishment flow path and a state in which the blocking state is released; a control unit that controls the first valve, the second valve, the bypass on-off valve, and the replenishment on-off valve; an operation unit that enables an auxiliary setting operation by an operator and switches to a first setting state when the auxiliary setting operation is performed; Equipped with The control unit is During a heating operation in which the heated heat medium is supplied to at least one of the first heat dissipation terminal and the second heat dissipation terminal, when the first valve is closed and the second valve is opened, the bypass opening / closing valve is controlled to be open; When the heating operation is stopped and the operation unit is in the first setting state, the bypass opening / closing valve is controlled to be in an open state and the supplementary opening / closing valve is controlled to be in a closed state. Hot water heater.

[0011] In the hot water heater of the above [1], if the first valve is controlled to be closed and the second valve is controlled to be open during heating operation, the heat medium heated in the first heat exchanger is not supplied to the first heat dissipation terminal because the first valve is closed, and the heat medium can be supplied to the second heat dissipation terminal to dissipate heat. In this way, if the bypass opening / closing valve is controlled to be open with the first valve closed and the second valve open, the heat medium flowing through the first internal flow path passes through the bypass flow path, is mixed in the common return flow path, and is supplied to the expansion tank. With this operation, the hot water heater can use the heat of the first heat exchanger that is not used by the first heat dissipation terminal for dissipating heat from the second heat dissipation terminal.

[0012] On the other hand, in the case of draining the heat medium from the flow path to prevent the heat medium (for example, hot water, etc.) from freezing in winter or when the house is not occupied immediately after completion, the operator may perform an auxiliary setting operation on the first operation unit when the heating operation is stopped. When the auxiliary setting operation is performed when the heating operation is stopped, the control unit opens the bypass opening / closing valve and closes the refill opening / closing valve. When the bypass opening / closing valve is in an open state, the bypass flow path can be used to discharge the heat medium present in the common return flow path when draining the heat medium. At this time, if the refill opening / closing valve is in an open state, the heat medium continues to be supplied to the expansion tank, and there is a concern that the heat medium in the flow path cannot be sufficiently drained. Regarding this problem, the above-mentioned hot water heater can close the refill opening / closing valve to cut off the supply of the heat medium to the tank when the auxiliary setting operation is performed on the operation unit, so that the heat medium can be prevented from remaining in the flow path due to the heat medium being continuously supplied to the tank when draining the heat medium.

[0013] [2] A second heat exchanger is provided for heating a portion of the common return flow path; the tank has a supply port through which the heat medium is supplied from the refill passage, an inlet portion connected to the common return passage, and an outlet portion connected to the common supply passage, The inlet is formed in a lower portion of the tank, the common return flow path includes a lower flow path passing through the inlet portion and a portion lower than the second heat exchanger, The bypass flow passage is connected to the low-level flow passage and is disposed at a lower position than the low-level flow passage. The hot water heater according to [1].

[0014] In the hot water heater / heating device of [2] above, a part of the common return flow path has a low-level flow path that is lower than the inlet of the tank and the second heat exchanger, so there is a concern that the heat medium will tend to remain in the low-level flow path when the heat medium is drained. However, in the hot water heater / heating device of [2] above, a bypass flow path is connected to the low-level flow path and is disposed at a lower position than the low-level flow path, so the heat medium in the low-level flow path is easily discharged via the bypass flow path when the heat medium is drained.

[0015] [3] Equipped with a liquid-liquid heat exchanger for heating the bath circuit; The first internal flow path has a reheating branching portion where a pipe branches off from the first internal flow path, The pipe branched from the reheating branch portion is arranged to pass through the liquid-liquid heat exchanger and is connected to the common return flow path, The reheating branch portion is disposed upstream of a connection portion of the first internal flow path with the bypass flow path. A hot water heater according to [1] or [2].

[0016] In the hot water heater of [3] above, the reheating branch section is located upstream of the “connection section of the first internal flow path with the bypass flow path”, so that when the heat transfer medium is discharged, the heat transfer medium discharged through the bypass flow path can be prevented from flowing into the liquid-liquid heat exchanger through the reheating branch section.

[0017] [4] The control unit is performing a freeze prevention operation in which the pump is driven when a freeze prevention condition is satisfied; Even if the freeze prevention condition is satisfied, when the operation unit is in the first setting state, the freeze prevention operation is not performed. A hot water heater according to any one of [1] to [3].

[0018] The hot water heater in [4] above prevents the pump from operating when in the first setting state (i.e., when there is a high possibility that the flow path is not sufficiently filled with heat medium), and can suppress problems caused by operating the pump when there is little or no heat medium (for example, failures caused by excessive operation of the pump when proper flow is not achieved).As another method, for example, when the presence or absence of heat medium in the flow path is detected by a sensor (for example, a water level sensor in an expansion tank, etc.) and the operation of the pump is stopped when there is no heat medium in the flow path, it is assumed that the presence or absence of the heat medium cannot be accurately detected due to the accuracy or failure of the sensor, but the hot water heater in [4] above can more reliably suppress problems (failures, etc.) caused by operating the pump when there is little or no heat medium in the flow path.

[0019] [5] A hot water supply and heating system comprising: a first heat dissipation terminal having the first valve; a second heat dissipation terminal; and a hot water supply and heating unit described in any one of [1] to [4] having the second valve.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 out 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 a heat medium flowing through the bath heating pipe 51 and hot and cold water flowing through the bath circulation path 63.

[0030] 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.

[0031] 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.

[0032] 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) through a heat medium circulation path 48. In this embodiment, the heat medium is, for example, hot water. Note that a fluid other than hot water may be used as the heat medium. 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 container 1A, and a temperature sensor 82 that detects the temperature of the heating combustion chamber 6A is provided in the partition member 80.

[0033] 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.

[0034] 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 an example of a first heat exchanger and a heating side second heat exchanger 32B corresponding to an example of a 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 is supplied with exhaust gas (combustion exhaust gas) generated by burning gas in the heating burner 33A (gas burner), and functions to heat the heat medium passing through the heating-side first heat exchanger 32A with the heat of the combustion exhaust gas. The heating-side first heat exchanger 32A recovers sensible heat from the combustion exhaust gas discharged from the heating-side burner unit 33. The heating-side second heat exchanger 32B is supplied with gas remaining after the combustion exhaust gas has passed through the heating-side first heat exchanger 32A, and functions to heat the heat medium passing through the heating-side second heat exchanger 32B with the gas. The heating-side second heat exchanger 32B recovers latent heat from the combustion exhaust gas discharged from the heating-side burner unit 33.

[0035] 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 common outflow path 38K as a heating outflow piping, a first internal flow path 38A as a heating high-temperature outflow piping, a second internal flow path 38B as a heating low-temperature outflow piping, and a common return flow path 38C as a heating return piping.

[0036] 1, the heat medium circulation path 48 is configured to circulate the heat medium through the common forward flow path 38K, the first internal flow path 38A, the first terminal flow path 38G of the first heat radiation terminal 39A, and the common return flow path 38C when the first heat radiation terminal 39A is connected as a heating terminal. When the second heat radiation terminal 39Z is connected as a heating terminal, the heat medium circulation path 48 is configured to circulate the heat medium through the common forward flow path 38K, the second internal flow path 38B, the second terminal flow path 38H of the second heat radiation terminal 39Z, and the common return flow path 38C.

[0037] The first internal flow path 38A is connected to the first heat dissipation terminal 39A as a flow path so as to communicate with the first terminal flow path 38G provided outside the hot water heater 1. The first internal flow path 38A is configured as a flow path branching from the branching portion 38J, and is configured as a flow path for flowing the heat medium from the branching portion 38J to the first heat dissipation terminal 39A. A part of the first internal flow path 38A is provided in the heating-side first heat exchanger 32A, and is configured so that the heat medium passing through the first internal flow path 38A is heated in the heating-side first heat exchanger 32A.

[0038] Second internal flow path 38B is connected to second heat dissipation terminal 39Z as a flow path so as to communicate with second terminal flow path 38H provided outside hot water heater 1. Second internal flow path 38B is configured as a flow path branching from branching portion 38J, and is configured as a flow path for flowing the heat medium from branching portion 38J to second heat dissipation terminal 39Z.

[0039] The heating circuit 3 further includes an expansion tank 36 which corresponds to an example of a tank, a heating circulation pump 37 which corresponds to an example of a pump, a heating high temperature thermistor 40, and a heating low temperature thermistor 41.

[0040] The common return flow passage 38C is a flow passage through which the heat medium flowing into the inlet portion 35A returns to the expansion tank 36. In the example of FIG. 1, the upstream end of the common return flow passage 38C is the inlet portion 35A, and the downstream end of the common return flow passage 38C is connected to the inlet portion 36C of the expansion tank 36. The common return flow passage 38C is configured as a pipe that introduces the heat medium from the first heat dissipation terminal 39A and the heat medium from the second heat dissipation terminal 39Z into the inside through the inlet portion 35A and flows through the heating side heat exchanger 32 (heating side second heat exchanger 32B). The common return flow passage 38C is configured to communicate with the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and is connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z as a flow passage through which the heat medium flows.

[0041] Between the outlet of the heating side second heat exchanger 32B and the inlet of the heating side first heat exchanger 32A, an intermediate pipe 38D and an intermediate pipe 38E are provided, and an expansion tank 36 and a heating circulation pump 37 are provided in the path of the intermediate pipes 38D and 38E, and a heat medium can flow from the heating side second heat exchanger 32B to the heating side first heat exchanger 32A through the intermediate pipe 38D, the expansion tank 36, and the intermediate pipe 38E. The intermediate pipe 38D is a part of the common return flow path 38C, and is a flow path between the outlet of the heating side second heat exchanger 32B and the inlet part 36C of the expansion tank 36. The intermediate pipe 38E is a pipe constituted by the common forward flow path 38K and a part of the first internal flow path 38A, and is provided between the outlet part 36B of the expansion tank 36 and the inlet of the heating side first heat exchanger 32A.

[0042] The common outflow flow path 38K is configured as a flow path that introduces the heat medium flowing out from the outlet portion 36B and flows the heat medium flowing out from the expansion tank 36. A heating circulation pump 37 is provided midway along the common outflow flow path 38K. The heating circulation pump 37 causes the heat medium in the common outflow flow path 38K to flow from the expansion tank 36 side to the branch portion 38J side.

[0043] 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 return flow path 38C. The first heat dissipation terminal 39A is, for example, a high-temperature heating terminal such as a heater blower 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.

[0044] 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.

[0045] 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.

[0046] In the heating circuit 3, the heating circulation pump 37 is operated to circulate hot water heated in the heating side heat exchanger 32 through the heat medium circulation path 48. Specifically, in the heating circuit 3, when the heating circulation pump 37 is operated, 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 return flow path 38C, the first internal flow path 38A, and the first heat dissipation terminal 39A, and also circulates through the common return flow path 38C, the second internal flow path 38B, and the second heat dissipation terminal 39Z. In the example of FIG. 1, hot water is supplied to the first heat dissipation terminal 39A 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.

[0047] 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 return flow path 38C so as to communicate with both.

[0048] 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.

[0049] The hot water heater 1 further includes 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, the heating circuit 3, the bath circuit 4, etc. The room temperature thermistor is provided, for example, in a dressing room as an air temperature detection means that detects the temperature in the dressing room. The control device 70 may be configured as a single device (for example, a controller configured as a single unit, etc.) or may be configured as multiple devices.

[0050] 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.

[0051] 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.

[0052] (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.

[0053] 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.

[0054] (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.

[0055] 3. Configuration for supplying heat medium to the first heat dissipation terminal 39A (high-temperature heating terminal) and the second heat dissipation terminal 39Z (low-temperature heating terminal) The hot water heater 1 forms a hot water system when connected to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, and supplies a heat transfer medium diverted from an internal branched flow path to the external first heat dissipation terminal 39A and second heat dissipation terminal 39Z.

[0056] As shown in FIG. 1, the downstream end of the common forward flow path 38K in the heat medium circulation path 48 is the branch section 38J. The branch section 38J is a part that branches the flow of the heat medium that has flowed through the common forward flow path 38K. The upstream side of the branch section 38J is the common forward flow path 38K, and the downstream side of the branch section 38J branches into the first internal flow path 38A and the second internal flow path 38B. The first internal flow path 38A has a reheating branch section 56 that branches into the bath circuit 4, and the bath circuit 4 side branched at the reheating branch section 56 has a bath heating pipe 51 passing through the bath heat exchanger 50 and connected to the common return flow path 38C. The lower side (downstream side) of the reheating branch section 56 has a connection section 46B that branches into the bypass flow path 46.

[0057] The bypass flow path 46 is provided between the common return flow path 38C and the first internal flow path 38A. The bypass flow path 46 is a path that allows the heat medium to flow so as to bypass between the common return flow path 38C and the first internal flow path 38A.

[0058] The downstream end of the first internal flow path 38A is a first outlet section 35B that can be connected to the outside and through which the heat medium flows out. The first outlet section 35B is provided at the downstream end of the first internal flow path 38A and is configured as an outlet that flows out the heat medium from the first internal flow path 38A toward the first terminal flow path 38G. The downstream end of the second internal flow path 38B is a second outlet section 35C that can be connected to the outside and through which the heat medium flows out. The second outlet section 35C is provided at the downstream end of the second internal flow path 38B and is configured as an outlet that flows out the heat medium from the second internal flow path 38B toward the second terminal flow path 38H. The upstream end of the common return flow path 38C is an inlet section 35A that can be connected to the outside and through which the heat medium flows in. The inlet section 35A is located downstream of the first terminal flow path 38G and downstream of the second terminal flow path 38H, and is an inlet through which the heat transfer medium flows in after flowing through the first terminal flow path 38G, and also an inlet through which the heat transfer medium flows in after flowing through the second terminal flow path 38H.

[0059] Outside the hot water heater 1, a first heat dissipation terminal 39A and a second heat dissipation terminal 39Z are provided, which are supplied with a heat medium from the hot water heater 1 and communicate with a heat medium circulation path 48. The first heat dissipation terminal 39A has a first terminal flow path 38G through which the heat medium flows, and dissipates heat from the heat medium flowing through the first terminal flow path 38G. In the space near the first heat dissipation terminal 39A, the air is heated by dissipating heat from the heat medium flowing through the first terminal flow path 38G. The first heat dissipation terminal 39A is configured as a high-temperature heating terminal. The second heat dissipation terminal 39Z has a second terminal flow path 38H through which the heat medium flows, and dissipates heat from the heat medium flowing through the second terminal flow path 38H. In the space near the second heat dissipation terminal 39Z, the air is heated by dissipating heat from the heat medium flowing through the second terminal flow path 38H. A downstream end of first terminal flow path 38G and a downstream end of second terminal flow path 38H are connectable to inlet 35A of hot water heater 1 so as to communicate with each other.

[0060] The supply of the heat medium to the first terminal flow path 38G is switched between a state in which the supply of the heat medium is blocked and a state in which the supply of the heat medium is permitted by opening and closing the first valve 39H. When the first valve 39H is open, the heat medium is permitted to pass through the first valve 39H, and the heat medium is permitted to flow from the first internal flow path 38A through the first terminal flow path 38G to the downstream side (the inlet section 35A side) of the first valve 39H. When the first valve 39H is closed, the heat medium is blocked from passing through the first valve 39H, and the heat medium does not flow from the first internal flow path 38A to the downstream side of the first valve 39H. The supply of the heat medium to the second terminal flow path 38H is switched between a state in which the supply of the heat medium is blocked and a state in which the supply of the heat medium is permitted by opening and closing the second valve 39G. When the second valve 39G is open, the heat medium is allowed to pass through the second valve 39G, and the heat medium is allowed to flow from the second internal flow path 38B through the second terminal flow path 38H to the downstream side (the inlet part 35A side) of the second valve 39G. When the second valve 39G is closed, the heat medium is blocked from passing through the second valve 39G, and the heat medium does not flow from the second internal flow path 38B to the downstream side of the second valve 39G. Both the first valve 39H and the second valve 39G are thermal valves. For example, when the power is turned on, the thermal valve expands the expansion body with the heat of the heating element (positive temperature coefficient) to push the piston and open the valve, allowing hot and cold water to flow, and when the power is turned off, the heating element naturally releases heat and the expansion body contracts, closing the valve.

[0061] The heat medium that has flowed into the inlet section 35A circulates in the heat medium circulation path 48 in the hot water heater 1. Specifically, the heat medium flows downstream from the inlet section 35A through the common return flow path 38C, is heated in the heating-side second heat exchanger 32B, passes through the expansion tank 36, and moves further downstream by the power of the heating circulation pump 37. Then, the heat medium that has flowed toward the branch section 38J is separated at the branch section 38J into the heat medium that flows toward the first internal flow path 38A and the heat medium that flows toward the second internal flow path 38B. The heat medium flowing through the first internal flow path 38A is heated in the heating-side first heat exchanger 32A along the way.

[0062] The heat medium flowing through the first internal flow path 38A is discharged from the first outlet portion 35B toward the first terminal flow path 38G. The heat medium flowing through the second internal flow path 38B is discharged from the second outlet portion 35C toward the second terminal flow path 38H.

[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 a control device 70. The control device 70 is electrically connected to each of the first valve 39H, the second valve 39G, and the heating circulation pump 37, and controls the opening and closing of the first valve 39H and the second valve 39G, and the drive of the heating circulation pump 37.

[0064] 4. Configuration related to draining water (draining heat medium) from hot water heater 1 The expansion tank 36 is configured to store a heat transfer medium (e.g., hot water). The expansion tank 36 has a supply port 36A to which the heat transfer medium is supplied from the hot water supply circuit 2, an inlet portion 36C connected to a common return flow path 38C, and an outlet portion 36B connected to a common forward flow path 38K.

[0065] The inlet 36C and the outlet 36B are formed through the bottom surface, which is the lower part of the expansion tank 36, and the supply port 36A is formed through the lid at the upper part of the expansion tank 36. A relief hole 36D is formed at the upper part of the side wall of the expansion tank 36 to release the increased heat medium to the outside. The heat medium discharged from the relief hole 36D is returned to the hot water supply circuit 2 side.

[0066] The supply port 36A is connected to a refill passage 42, which is a passage for refilling the heat medium from the hot water supply circuit 2 side. In the example of FIG. 1, one end of the refill passage 42 is connected to the vicinity of the inlet of the water supply pipe 11 (in the example of FIG. 1, upstream of the control valve 13A), and the other end of the refill passage 42 is connected to the supply port 36A of the expansion tank 36, and is configured as a pipe branched off from the water supply pipe 11. The refill passage 42 is provided with a refill on-off valve 43 that switches between a state in which the flow of the heat medium is blocked and a state in which the flow of the heat medium is permitted. A thermal valve is used for the refill on-off valve 43, which is electrically connected to the control device 70 and opens and closes in response to a signal from the control device 70. The internal space on one end side (the water supply pipe 11 side) of the replenishment passage 42 is filled with water under a configuration in which water pressure is applied by the water in the water supply pipe 11, and when the replenishment on-off valve 43 is in an open state (a state in which the flow of the heat medium is permitted and the cut-off state is released), water (heat medium) is supplied from the water supply pipe 11 through the replenishment passage 42 to the expansion tank 36. When the replenishment on-off valve 43 is in a closed state (a cut-off state in which the flow of the heat medium is cut off), water (heat medium) is not supplied from the water supply pipe 11 to the expansion tank 36.

[0067] The intermediate piping 38D between the heating-side second heat exchanger 32B and the expansion tank 36 in the common return flow path 38C is a recessed portion 49 of the piping that forms a path that turns back vertically on the inlet portion 36C side of the expansion tank 36. The recessed portion 49 has a low-level flow path 49A that extends horizontally and through which the heat medium flows. The low-level flow path 49A is formed in a position that is entirely lower than the inlet portion 36C, the heating-side first heat exchanger 32A, and the heating-side second heat exchanger 32B.

[0068] A connection portion 46A of the bypass flow passage 46 with the low-level flow passage 49A is provided at a middle portion of the low-level flow passage 49A in the traveling direction of the heat medium. A bypass on-off valve 47 is provided in the bypass flow passage 46. The bypass on-off valve 47 is switched between a state in which the flow of the heat medium in the bypass flow passage 46 is suppressed (suppression state) and a state in which the suppression state is released (suppression release state) in response to an instruction from the control device 70. When the bypass on-off valve 47 is in the suppression state, the opening degree (cross-sectional area of ​​the space through which the heat medium passes) near the bypass on-off valve 47 in the bypass flow passage 46 becomes relatively small, and when in the suppression release state, the opening degree near the bypass on-off valve 47 becomes relatively large. Specifically, a main flow passage in which the cross-sectional area of ​​the space through which the heat medium passes is large and an auxiliary flow passage in which the cross-sectional area of ​​the space through which the heat medium passes is significantly smaller than that of the main flow passage are provided near the bypass on-off valve 47 in the bypass flow passage 46. The space in the auxiliary flow passage is much narrower than the space in the main flow passage, and the cross-sectional area of ​​the narrowest part of the space in the auxiliary flow passage (cross-sectional area in a direction perpendicular to the flow direction) is much smaller than the cross-sectional area of ​​the narrowest part of the space in the main flow passage (cross-sectional area in a direction perpendicular to the flow direction). When the bypass on-off valve 47 is in the suppression state, the flow in the main flow passage is blocked in the bypass flow passage 46, and only the auxiliary flow passage is allowed to flow, and the flow rate of the heat medium is significantly reduced. When the bypass on-off valve 47 is in the non-suppression state, both the main flow passage and the auxiliary flow passage are allowed to flow. The bypass on-off valve 47 is, for example, a thermal valve, is electrically connected to the control device 70, and opens and closes in response to a signal from the control device 70.

[0069] When the heating circulation pump 37 is operating, the heat medium pushed out by the heating circulation pump 37 provided between the expansion tank 36 and the branching portion 38J generates pressure from the branching portion 38J toward the first heat dissipation terminal 39A side and the second heat dissipation terminal 39Z side. Therefore, when the heating circulation pump 37 is operating and the supply of heat medium to the first heat dissipation terminal 39A is cut off and the bypass opening / closing valve 47 is in an open state, the heat medium that cannot move to the first heat dissipation terminal 39A side passes through the bypass flow path 46 and is mixed with the heat medium in the common return flow path 38C and enters the expansion tank 36.

[0070] On the other hand, when the heating circulation pump 37 is stopped, the pressure of the heat medium is not generated by the operation of the heating circulation pump 37, so the heat medium is subjected to a force in the direction of moving from higher to lower due to gravity. Therefore, when the lower drain plug is opened, the heat medium moves downward regardless of the opening and closing states of the first valve 39H and the second valve 39G for supplying the heat medium to the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z. Therefore, for example, when the bypass opening and closing valve 47 is open, the heat medium in the expansion tank 36 flows from the recessed portion 49 of the common return flow path 38C through the bypass flow path 46 to the downstream side of the first internal flow path 38A, and is discharged from the drain hole (not shown) when the drain plug is removed.

[0071] The hot water heater 1 includes a first operation unit 73 that allows an operator to perform a predetermined auxiliary setting operation. The first operation unit 73 is configured to switch to a first setting state when the operator performs the auxiliary setting operation. The first operation unit 73 is, for example, a DIP (Dual In-line Package) switch, and is configured to allow a setting as to whether or not to perform water draining. Specifically, the auxiliary setting operation is, for example, changing the displacement of a predetermined operation unit (for example, a slidable lever or a rotatable shaft) provided on the DIP switch to a first displacement and maintaining it. The auxiliary setting operation causes the first operation unit 73 (for example, a DIP switch) to a first displacement, and the state in which this first displacement is maintained is the first setting state. The case in which the first operation unit 73 is in the first setting state is a case in which "a setting to perform water draining is performed", and the control device 70 sets a water draining flag (F1=1) on the condition that the first operation unit 73 is in the first setting state, for example, holds the water draining flag so as to be stored in a predetermined storage unit, and controls subsequent operations according to the water draining flag. In addition, when the first operating unit 73 is not in the first setting state, this is the case where "the setting to perform water draining has not been made," and when the first operating unit 73 is not in the first setting state, the control device 70 does not set the water draining flag and sets F1=0.

[0072] 5. Processing of the control device 70 (When heating) The heating operation period is a period during which gas is burned in the heating burner 33A (gas burner) and the heat medium is circulated in the heat medium circulation path 48. In this embodiment, the control device 70 controls the first valve 39H, the second valve 39G, the bypass opening / closing valve 47, and the supplementary opening / closing valve 43. For example, the control device 70 performs necessary heating by controlling to open the first valve 39H during heating using the high-temperature first heat dissipation terminal 39A and to open the second valve 39G during heating using the low-temperature second heat dissipation terminal 39Z.

[0073] When performing a heating operation (third heating operation) to supply a heated heat medium to both the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, or when performing a heating operation (first heating operation) to supply a heated heat medium to the first heat dissipation terminal 39A while not supplying the heat medium to the second heat dissipation terminal 39Z, the bypass opening / closing valve 47 is closed, so that the amount of heat medium flowing in the bypass flow path 46 becomes very small or does not flow at all. Specifically, when performing the first heating operation, the control device 70 opens the first valve 39H, closes the second valve 39G, and closes the bypass opening / closing valve 47 (restricted state of the bypass flow path 46), burns gas in the heating burner 33A, and drives the heating circulation pump 37 to circulate the heat medium. When performing the third heating operation, the control device 70 opens the first valve 39H, opens the second valve 39G, and closes the bypass on-off valve 47 (suppressing the bypass flow path 46), combusts gas in the heating burner 33A, and drives the heating circulation pump 37 to circulate the heat medium.

[0074] On the other hand, when performing a heating operation (second heating operation) in which a heated heat medium is supplied to the second heat dissipation terminal 39Z and dissipated at the second heat dissipation terminal 39Z while not supplying the heat medium to the first heat dissipation terminal 39A, the control device 70 controls the bypass opening / closing valve 47 to be open. As a result, the heat medium heated in the heating side first heat exchanger 32A passes through the bypass flow path 46 and merges with the common return flow path 38C, and is used to heat the second heat dissipation terminal 39Z. Specifically, when performing the second heating operation, the control device 70 closes the first valve 39H, opens the second valve 39G, and opens the bypass opening / closing valve 47 (restriction release state of the bypass flow path 46), burns gas in the heating burner 33A, and drives the heating circulation pump 37 to circulate the heat medium.

[0075] When the heat medium is not supplied to both the first heat dissipation terminal 39A and the second heat dissipation terminal 39Z, the control device 70 closes the first valve 39H and closes the second valve 39G.

[0076] (When draining water) The control device 70 executes the control of Fig. 2 in response to the establishment of a predetermined first start condition. The first start condition may be that the control device 70 is powered on, that a predetermined operation is performed in the hot water heater 1, that the control of Fig. 2 is terminated, or any other condition.

[0077] When the control device 70 starts the control of Fig. 2, it judges in step S11 whether the first operation unit 73 has become the ON state. In this embodiment, the above-mentioned first setting state is the ON state, and when the control device 70 judges in step S11 that the first operation unit 73 is in the first setting state, it judges as Yes and proceeds to the process of step S12, and when the control device 70 judges in step S11 that the first operation unit 73 is not in the first setting state, it judges as No and repeats the process of step S11 until it judges as Yes in step S11. After the control of Fig. 2 starts, when the operator turns on the water draining start switch of the first operation unit 73 (specifically, when the first operation unit 73 (e.g., DIP switch) is set to the first displacement), it judges as Yes in step S11.

[0078] When the control device 70 determines in step S11 that the first operating unit 73 is in the on state (when the control device 70 determines that the first operating unit 73 is in the first setting state), the control device 70 sets a water draining flag in step S12 (S12). In the example of Fig. 2, the control device 70 sets the water draining flag F1 to 1 in step S12.

[0079] After setting F1=1 in step S12, the control device 70 judges whether a predetermined cancellation condition is satisfied in step S13. In this embodiment, the predetermined cancellation condition is to satisfy at least one of the following: a heating operation is being performed or a reheating operation is being performed. The period during which the heating operation is being performed corresponds to at least one of the following periods: a period from when a first predetermined operation is performed by a predetermined operation means (e.g., an operation means not shown) to start the heating operation of the first heat radiating terminal 39A (an operation of supplying a heated heat medium to the first heat radiating terminal 39A) until the heating operation of the first heat radiating terminal 39A ends, or a period from when a second predetermined operation is performed to start the heating operation of the second heat radiating terminal 39Z (an operation of supplying a heated heat medium to the second heat radiating terminal 39Z) until the heating operation of the second heat radiating terminal 39Z ends. The period during which the reheating operation is being performed is, for example, the period from when a specified operation that is a condition for starting the automatic filling operation or the automatic reheating operation is performed on a specified operating means (for example, the bath remote control 72) to when reheating is completed in the bath circuit 4.

[0080] If the control device 70 determines in step S13 that the predetermined cancellation condition is met (i.e., at least either the heating operation or the reheating operation is being performed), the process proceeds to step S14, and the water draining flag F1 is reset to 0. If the control device 70 determines in step S13 that the predetermined cancellation condition is not met (i.e., neither the heating operation nor the reheating operation is being performed), the process proceeds to step S15.

[0081] After step S14, or if the determination in step S13 is No, the control device 70 determines in step S15 whether or not the water draining flag is set (that is, whether or not F1=1).

[0082] When the control device 70 determines in step S15 that the drainage flag is set (i.e., F1=1), it opens the bypass on-off valve 47 in step S16 to release the bypass flow path 46 (the suppression state is released), and shuts off the refill on-off valve 43. In this state, for example, when the drain plug that blocks the drain hole is manually removed by an operator, the heat medium in the common return flow path 38C flows through the bypass flow path 46 to the lower side of the first internal flow path 38A and is discharged from the drain hole. At this time, since the refill on-off valve 43 is in a closed state, the heat medium is not refilled from the refill flow path 42 to the expansion tank 36 even if the heat medium in the expansion tank 36 is drained. The position of the drainage hole is not limited to one position, but may be any hole that can release the heat medium from the first internal flow path 38A. For example, the drainage hole may be provided downstream of the connection part with the bypass flow path 46 in the first internal flow path 38A. For example, the lower flow path 49A is located lower than the expansion tank 36, the bypass flow path 46 is located lower than the low-level flow path 49A, and the "portion of the first internal flow path 38A downstream of the lower end of the bypass flow path 46" is located lower than the bypass flow path 46, and the water drainage path from the expansion tank 36 through the low-level flow path 49A, the bypass flow path 46, and the "portion of the first internal flow path 38A downstream of the connection with the bypass flow path 46" to the water drainage hole is preferably configured so that the closer to the water drainage hole, the lower the position.

[0083] When performing the process of step S16, the control device 70 may control the bypass opening / closing valve 47 to the suppressed state after a predetermined time (for example, about 2 to 5 minutes) has elapsed after opening the bypass opening / closing valve 47. Alternatively, the control device 70 may maintain the bypass opening / closing valve 47 in the "state in which the suppressed state is released" after starting the process of step S16 until at least one of the heating operation and the freeze prevention operation is started. After the water drainage is completed, the water drainage hole is blocked with a water drain plug (manually by an operator, etc.).

[0084] When the control device 70 determines in step S15 that the water drainage flag is not set (i.e., F1=0), in step S17, the control device 70 closes the bypass on-off valve 47 to set the bypass flow path 46 in the suppressed state and opens the refill on-off valve 43 (the state in which the shutoff state is released). When the release condition is not satisfied and the water drainage flag is not set (i.e., F1=0), the control device 70 opens the refill on-off valve 43 when the heat medium in the expansion tank 36 falls below a predetermined water level and maintains the refill on-off valve 43 in the open state until the predetermined water level is exceeded, thereby refilling the heat medium from the hot water supply circuit 2 side, and when the heat medium in the expansion tank 36 exceeds the predetermined water level, the control device 70 maintains the refill on-off valve 43 in the closed state to stop refilling the heat medium. When the release condition is not satisfied and the water drainage flag is not set (i.e., F1=0), the control device 70 maintains the bypass on-off valve 47 in the suppressed state until the condition for opening the bypass on-off valve 47 is satisfied.

[0085] (Anti-freeze operation) The control device 70 executes the control of Fig. 3 in response to the establishment of a predetermined second start condition. The second start condition may be that the control device 70 is powered on, that a predetermined operation is performed in the hot water heater 1, that the control of Fig. 3 is terminated, or any other condition.

[0086] When the control device 70 starts the control of FIG. 3, it judges whether or not the freeze prevention start condition is satisfied in step S21. The freeze prevention start condition is, for example, "the above-mentioned release condition is not satisfied, and the outside air temperature (the temperature at the position of the outside air temperature sensor 74) detected by the outside air temperature sensor 74 has reached a threshold temperature or lower." The threshold temperature can be a predetermined temperature close to the state where the heat medium freezes, and can be, for example, 5°C. The threshold temperature may be a temperature other than this. In a representative example, the freeze prevention start condition is satisfied when the above-mentioned heating operation is not being performed, the above-mentioned reheating operation is not being performed, and the outside air temperature detected by the outside air temperature sensor 74 has reached a threshold temperature or lower. The control device 70 is electrically connected to the outside air temperature sensor 74 that detects the temperature outside the hot water heater 1, and can receive information on the outside air temperature (information specifying the outside air temperature) output by the outside air temperature sensor 74.

[0087] If the control device 70 determines in step S21 that the above-mentioned heating operation is not being performed, the above-mentioned reheating operation is not being performed, and the outside air temperature detected by the outside air temperature sensor 74 has reached or exceeded the threshold temperature, the control device 70 proceeds to step S22. If this is not the case (i.e., if the control device 70 determines in step S21 that the freeze prevention start condition is not satisfied), the control device 70 repeats the determination in step S21 until the freeze prevention start condition is satisfied.

[0088] When the control device 70 advances the process to step S22, it determines in step S22 whether the water draining flag F1 is set (i.e., whether F1=1). When the control device 70 determines in step S22 that the water draining flag F1 is not set (i.e., F1=0), it performs freeze prevention operation in step S23. When the control device 70 determines in step S22 that the water draining flag F1 is set (i.e., F1=1), it ends the control in FIG. 3.

[0089] When performing freeze prevention operation in step S23, the control device 70 drives (operates) the heating circulation pump 37 to circulate the heat medium in the heat medium circulation path 48. When performing freeze prevention operation in step S23, the control device 70 desirably controls one or both of the first valve 39H and the second valve 39G to open. After starting the freeze prevention operation in step S23, the control device 70 ends the freeze prevention operation when a predetermined end condition is met. When performing freeze prevention operation, the control device 70 desirably drives the heating circulation pump 37 while keeping the heating burner 33A in a combustion-stopped state.

[0090] If the answer to step S22 is Yes, i.e., if the water drainage flag F1 is set (F1 = 1), the heat transfer medium in the flow path may have been drained by the above-mentioned water drainage, and anti-freeze operation should not be performed to prevent failure of the heating circulation pump 37, etc., so anti-freeze operation is not performed even if the anti-freeze start condition is met.

[0091] 6. Example of effects In the above-mentioned hot water heater 1, when the first heat dissipation terminal 39A is to dissipate heat during heating operation (regardless of whether the second heat dissipation terminal 39Z is dissipating heat or not), by controlling the first valve 39H to be open and the bypass opening / closing valve 47 to be closed, the heat medium heated in the heating side first heat exchanger 32A is supplied to the first heat dissipation terminal 39A, and the first heat dissipation terminal 39A can dissipate heat.

[0092] In the case where the first heat dissipation terminal 39A is not dissipated but the second heat dissipation terminal 39Z is dissipated during heating operation, if the first valve 39H is controlled to be closed and the second valve 39G is controlled to be open, the heat medium heated in the heating side first heat exchanger 32A is not supplied to the first heat dissipation terminal 39A because the first valve 39H is closed, and the heat medium is supplied to the second heat dissipation terminal 39Z to dissipate heat. In this way, if the bypass opening / closing valve 47 is controlled to be open with the first valve 39H closed and the second valve 39G open, the heat medium flowing through the first internal flow path 38A passes through the bypass flow path 46, is mixed in the common return flow path 38C, and is supplied to the expansion tank 36. With such an operation, the hot water heater 1 can use the heat of the heating side first heat exchanger 32A that is not used by the first heat dissipation terminal 39A for dissipating heat from the second heat dissipation terminal 39Z.

[0093] In winter or when the house is not occupied immediately after completion, when the heat medium (for example, hot water, etc.) is to be removed from the flow path to prevent freezing, the operator may perform an auxiliary setting operation on the first operation unit 73 when the heating operation is stopped. When the auxiliary setting operation is performed when the heating operation is stopped, the control device 70 opens the bypass opening / closing valve 47 and closes the refill opening / closing valve 43. When the bypass opening / closing valve 47 is in an open state, the bypass flow path 46 can be used to discharge the heat medium present in the common return flow path 38C when the heat medium is to be removed. At this time, if the refill opening / closing valve 43 is in an open state, the heat medium continues to be supplied to the expansion tank 36, and there is a concern that the heat medium in the flow path cannot be sufficiently removed. Regarding this problem, when the auxiliary setting operation is performed on the first operation unit 73, the hot water heater 1 can close the refill opening / closing valve 43 to cut off the supply of the heat medium to the expansion tank 36, so that the heat medium can be prevented from remaining in the flow path due to the heat medium being continuously supplied to the expansion tank 36 when the heat medium is removed.

[0094] In the hot water heater 1, a part of the common return flow path 38C has a low-level flow path 49A that is lower than the inlet portion 36C of the expansion tank 36 and the heating-side second heat exchanger 32B, so there is a concern that the heat medium will tend to remain in the low-level flow path 49A when the heat medium is drained. However, in the hot water heater 1, the bypass flow path 46 is connected to the low-level flow path 49A and is disposed at a lower position than the low-level flow path 49A, so that the heat medium in the low-level flow path 49A is easily discharged via the bypass flow path 46 when the heat medium is drained.

[0095] In the hot water heater 1, the reheating branch section 56 is positioned upstream of the "connection section of the first internal flow path 38A with the bypass flow path 46," so that when the heat medium is discharged, the heat medium discharged through the bypass flow path 46 can be prevented from flowing through the reheating branch section 56 into the liquid-liquid heat exchanger.

[0096] <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.

[0097] In the above embodiment of the hot water heater 1, the common return flow path 38C is configured to have a low-level flow path 49A of the concave portion 49, but this configuration is not limited to this and the configuration may not include a low-level flow path 49A of the concave portion 49.

[0098] In the hot water heater 1 of the above embodiment, the "water draining flag release condition" used in the judgment of step S13 in Fig. 2 is whether or not either the first valve 39H or the second valve 39G is open, or whether or not the reheating switch is turned on, but is not limited to such examples. The water draining flag release condition may be, for example, that the cumulative combustion time of the burners 8A, 33A reaches a predetermined time (e.g., 10 hours). In this case, it is expected that the construction worker will finish the work and leave the site before the release condition is satisfied, so that it is possible to prevent the worker from misunderstanding that a malfunction has occurred due to the freeze prevention operation being started in the middle of the construction work.

[0099] The hot water heater 1 in the above embodiment is configured to reduce the amount of heat medium flowing through the bypass flow path 46 when the bypass on-off valve 47 is in the suppression state compared to when the suppression is released, but is not limited to this configuration and may be configured to block flow from one side of the intermediate piping 38D and the first internal flow path 38A to the other side via the bypass flow path when the bypass on-off valve is in the suppression state.

[0100] The hot water heater 1 of the above embodiment is configured to include the heating-side second heat exchanger 32B, but is not limited to this configuration and may be configured not to include the heating-side second heat exchanger 32B. In this case, the common return flow path 38C may be configured so that the heat medium flows from the inlet portion 35A to the inlet portion 36C of the expansion tank 36 without passing through a heat exchanger.

[0101] 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]

[0102] 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 32A: Heating side first heat exchanger (first heat exchanger) 32B: Heating side second heat exchanger (second heat exchanger) 33: Heating side burner unit 33A: Heating burner (gas burner) 34A: Burner block 34B: Burner block 35A: Inflow section 35B: 1st outlet 35C: 2nd outlet 36: Expansion tank (tank) 36A: Supply port 36C: Entrance section 36B: Exit part 37: Heating circulation pump (pump) 38A: First internal flow passage 38B: Second internal flow passage 38C: Common return flow path 38K: Common outbound flow path 38J: Branch 39A: First heat dissipation terminal 39Z: Second heat dissipation terminal 38G: First terminal channel 38H: Second terminal channel 39H: First valve 39G: Second valve 42: Refill channel 43: Refill valve 46: Bypass flow path 46A, 46B: Connection part 47: Bypass valve 48: Heat medium circulation path 49: Concave part 49A: Low level flow path 50: Bath heat exchanger 56: Reheating branch section 70: Control device (control unit) 73: 1st operation section 74: Outside air temperature sensor 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, A tank for storing the heat transfer medium; A gas burner for burning gas; a first heat exchanger to which combustion exhaust gas generated by combustion of the gas burner is supplied and which heats the heat transfer medium; an inlet portion provided downstream of the first terminal flow path and downstream of the second terminal flow path, the inlet portion being an inlet into which the heat medium flowing through the first terminal flow path flows and an inlet into which the heat medium flowing through the second terminal flow path flows; a common return flow path through which the heat transfer medium that has flowed into the inlet returns to the tank; a common inflow flow path which is a flow path for flowing the heat transfer medium flowing out of the tank; A branching portion that branches the flow of the heat medium that has flowed through the common inflow flow path; a pump provided in the common forward flow passage for causing the heat medium to flow; a first internal flow path that is configured as a flow path branched from the branching portion, a portion of which is heated by the first heat exchanger, and which 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 bypass flow path that is a path for bypassing the heat medium between the common return flow path and the first internal flow path; a refilling passage for refilling the tank with the heat medium from outside the tank; a bypass on-off valve that switches between a suppression state in which the flow of the heat medium in the bypass flow passage is suppressed and a state in which the suppression state is released; a replenishment on-off valve that switches between a blocking state in which the flow of the heat medium is blocked in the replenishment flow path and a state in which the blocking state is released; a control unit that controls the first valve, the second valve, the bypass on-off valve, and the replenishment on-off valve; an operation unit that enables an auxiliary setting operation by an operator and that switches to a first setting state when the auxiliary setting operation is performed; Equipped with The control unit is During a heating operation in which the heated heat medium is supplied to at least one of the first heat dissipation terminal and the second heat dissipation terminal, when the first valve is closed and the second valve is opened, the bypass opening / closing valve is controlled to be open; When the heating operation is stopped, if the operation unit is in the first setting state, the bypass opening / closing valve is controlled to be in an open state and the supplementary opening / closing valve is controlled to be in a closed state. Hot water heater.

2. a second heat exchanger for heating a portion of the common return flow path; the tank has a supply port through which the heat medium is supplied from the refill passage, an inlet portion connected to the common return passage, and an outlet portion connected to the common supply passage, The inlet is formed in a lower portion of the tank, the common return flow path includes a lower flow path passing through the inlet portion and a portion lower than the second heat exchanger, The bypass flow passage is connected to the low-level flow passage and is disposed at a lower position than the low-level flow passage. The hot water heater according to claim 1.

3. A liquid-liquid heat exchanger for heating the bath circuit is provided, The first internal flow path has a reheating branch portion where a pipe branches off from the first internal flow path, The pipe branched from the reheating branch portion is arranged to pass through the liquid-liquid heat exchanger and is connected to the common return flow path, The reheating branch portion is disposed upstream of a connection portion of the first internal flow path with the bypass flow path. The hot water heater according to claim 1 or 2.

4. The control unit is performing a freeze prevention operation in which the pump is driven when a freeze prevention condition is satisfied; Even if the freeze prevention condition is satisfied, when the operation unit is in the first setting state, the freeze prevention operation is not performed. The hot water heater according to claim 1 or 2.

Images