JP7426083B2 - hot water system - Google Patents

Description

The present disclosure relates to a hot water supply system.

Patent Document 1 discloses a water heater that heats water in a heat exchanger by burning fuel. This water heater is equipped with a burner and a gas supply pipe that serves as a gas supply path to the burner. It is composed of branch pipes. The main pipe is provided with a source gas solenoid valve and a gas proportional valve, and each branch pipe is provided with a hot water supply gas solenoid valve. In this water heater, gas is supplied to the burner by simultaneously opening the source gas solenoid valve and the hot water supply gas solenoid valve, and the burner is ignited by continuous discharge from the ignition plug. In this water heater, after the burner is extinguished, the source gas solenoid valve and the hot water supply gas solenoid valve are closed.

Japanese Patent Application Publication No. 2016-200351

In the water heater of Patent Document 1, there is a risk that an abnormality may occur in the source gas solenoid valve or the hot water supply gas solenoid valve such that the gas supply path cannot be reliably closed. The method for detecting such an abnormality is to first close only one of the source gas solenoid valve and the hot water supply gas solenoid valve when extinguishing the burner, and check whether the burner continues to burn. A possible method is to detect an abnormality in one of the electromagnetic valves by detecting whether or not the electromagnetic valve is present. In a water heater that employs such an abnormality detection method, it is possible to test for abnormalities in both solenoid valves by first switching the solenoid valve that is closed for each extinguishing operation.

However, with this water heater, if the source gas solenoid valve is closed first, the fire will be completely extinguished after the gas remaining in the gas flow path downstream of the source gas solenoid valve has finished burning. . In other words, in this water heater, combustion continues even after the source gas solenoid valve is closed, so there are concerns about disadvantages due to excess heat being added to the water in the heat exchanger. The disadvantage of this is, for example, that heated water remains in the water heater after the source gas solenoid valve is closed, and the next time hot water is dispensed, feedback temperature control is performed based on the temperature of the heated remaining water. One problem is that it takes a long time to bring the hot water temperature close to the set temperature. Further, there is a possibility that disadvantages other than these problems may occur.

The present disclosure provides a technology that has a function of inspecting a plurality of electromagnetic valves provided in a gas flow path and can suppress the frequency at which combustion continues after the electromagnetic valve to be inspected is closed.

A hot water supply system according to one aspect of the present disclosure includes a water pipe that passes water introduced from the outside, a burner that burns combustion gas to generate exhaust gas, and a flow path that supplies the combustion gas to the burner. a gas flow path; a first solenoid valve that switches between an open state in which the gas flow path is opened and a closed state in which it is closed; and an open state in which the gas flow path is opened at a position downstream of the first solenoid valve; a second electromagnetic valve that switches to a closed state, a heat exchanger that is provided in the middle of the water pipe and that transfers heat of the exhaust gas to water passing through the water pipe, and a combustion termination condition. a first control in which the first solenoid valve is closed and the second solenoid valve is opened when the combustion termination condition is satisfied; and a second control in which the second solenoid valve is closed and the combustion termination condition is closed. a second control for opening a first electromagnetic valve; a detection section for detecting combustion in the burner; and a detection section for detecting combustion in the burner during the first control. a determination unit that performs a first determination process that determines whether or not combustion occurs in the burner, and a second determination process that determines whether combustion in the burner is detected by the detection unit during the second control. , the control section performs the first control when a predetermined time condition or device condition is satisfied when the combustion end condition is established, and performs the second control when the combustion end condition is not satisfied.

The hot water supply system according to one aspect of the present disclosure can inspect a plurality of solenoid valves provided in a gas flow path, and can suppress the frequency at which combustion continues after the solenoid valve to be inspected is closed.

FIG. 1 is a schematic circuit diagram illustrating a hot water supply system according to a first embodiment. FIG. 2 is a block diagram schematically illustrating a controller and a remote controller that constitute the hot water supply system according to the first embodiment. FIG. 3 is a flowchart illustrating the flow of hot water supply control performed in the hot water supply system of the first embodiment.

The following description relates to an example embodiment of a hot water supply system. Note that the features [1] to [3] shown below may be combined in any manner consistent with each other.

[1] A water pipe that passes water introduced from the outside, a burner that burns combustion gas to generate exhaust gas, a gas flow path that is a flow path that supplies the combustion gas to the burner, and the gas flow a first electromagnetic valve that switches between an open state in which the gas flow path is opened and a closed state in which the gas flow path is closed; and a first electromagnetic valve that switches between an open state in which the gas flow path is opened and a closed state in which the gas flow path is closed at a position downstream of the first solenoid valve. a second electromagnetic valve, a heat exchanger that is provided in the middle of the water pipe and that transfers the heat of the exhaust gas to the water passing through the water pipe, and a heat exchanger that is provided in the middle of the water pipe and transmits the heat of the exhaust gas to the water passing through the water pipe, and the first electromagnetic valve that a first control in which the second solenoid valve is opened while the valve is closed; and when the combustion termination condition is met, the second solenoid valve is closed and the first solenoid valve is opened. a second control; a detection unit that detects combustion in the burner; and a first control unit that determines whether combustion in the burner is detected by the detection unit during the first control. a determination unit that performs a determination process and a second determination process that determines whether combustion in the burner is detected by the detection unit during the second control, the control unit A hot water supply system that performs the first control when a predetermined time condition or device condition is satisfied when an end condition is established, and performs the second control when the predetermined time condition or device condition is not satisfied.

The hot water system in [1] above can detect whether there is an abnormality in the first solenoid valve by performing the first determination process, and can detect whether there is an abnormality in the second solenoid valve by performing the second determination process. can do. Therefore, this hot water supply system can inspect a plurality of solenoid valves provided in the gas flow path. Moreover, this hot water supply system performs the first control when a predetermined time condition or equipment condition is satisfied when the combustion termination condition is satisfied. In this way, in the hot water supply system described above, since performing the first control is limited by time conditions or equipment conditions, the frequency of inspection by the first control, that is, the first solenoid valve on the upstream side is subject to inspection. The frequency can be reduced. Therefore, this hot water supply system can suppress the frequency at which combustion continues after the solenoid valve to be inspected is closed.

[2] A blower that sends air into the heat exchanger; a drive unit that starts driving the blower when a blowing start condition is met and stops driving the blower when a blowing stop condition is met; The hot water supply system according to [1], wherein the control section performs the first control before the blowing operation in which the drive section drives the blower in response to establishment of the blowing start condition.

In the above hot water supply system [2], even if combustion continues after the first solenoid valve is closed by the first control and the vicinity of the heat exchanger is heated by this combustion, heat exchange is performed by driving the blower after the first control. can be cooled down. Therefore, even if extra heat is added to the water in the heat exchanger due to combustion after the first solenoid valve is closed, the temperature rise of the water in the heat exchanger can be suppressed or lowered by subsequent cooling. , it is possible to reliably suppress the disadvantages caused by excess heat being added to the water in the heat exchanger.

[3] The driving unit drives the blower when the self-diagnosis condition is satisfied, and the control unit performs the first control before the blowing operation in response to the self-diagnosis condition being satisfied.[2] ] The hot water system described in ].

In the hot water supply system of [3] above, even if combustion continues after the first solenoid valve is closed by the first control and the vicinity of the heat exchanger is heated by this combustion, the heat exchanger is heated by driving the blower after the first control. This makes it possible to reliably suppress the disadvantages caused by excess heat being added to the water in the heat exchanger. Moreover, since the above disadvantages can be suppressed by effectively utilizing the blower drive that is performed when the self-diagnosis conditions are met, the dedicated operation of driving the blower just to suppress the above disadvantages can be omitted or reduced. be able to.

<First embodiment>
The following description relates to the first embodiment.
(Basic configuration)
A hot water supply system 1 shown in FIG. 1 is configured as a bath and hot water supply system having a function of supplying hot water to a bathtub 60 and a function of heating water in the bathtub, and mainly includes a hot water supply side circuit 2 and a bath side circuit 3. The hot water supply side circuit 2 includes a water inlet pipe 12, a hot water outlet pipe 10, a gas burner 4 (burner), a hot water supply side heat exchanger 6 (heat exchanger), etc., and functions as a path for heating tap water supplied from the outside and discharging the hot water. do. The bath side circuit 3 includes a gas burner 54 (bath side burner), a bath side heat exchanger 56, piping 66, a circulation pump 62, thermistors 64 and 65, etc., and is used for circulating heating during automatic hot water filling, reheating the bath, etc. used for.

In the hot water supply side circuit 2, a pipe line constituted by the water inlet pipe 12, the heat transfer tube 8a, the piping 20, the heat transfer tube 7a, and the hot water outlet pipe 10 functions as a hot water supply side water passage. The water inlet pipe 12 is configured as a path through which water flows from the water inlet 16, and the hot water outlet pipe 10 is configured as a path through which hot water is sent to the hot water outlet 18. The gas burner 4 corresponds to an example of a burner, and is a part that burns gas (combustion gas) to generate exhaust gas. The hot water supply side heat exchanger 6 corresponds to an example of a heat exchanger, and allows water to pass through a hot water supply side water passage (a pipe line constituted by the water inlet pipe 12, the heat transfer pipe 8a, the pipe 20, the heat transfer pipe 7a, and the hot water outlet pipe 10). It is a part that transfers the heat generated by the gas burner 4 to boil water, and is installed in the middle of the hot water supply side water passage, and is a part that boils water by transferring the heat generated by the gas burner 4 to the water passing inside the hot water supply side water passage. It functions to conduct heat. The hot water supply side heat exchanger 6 includes a primary heat exchanger 7 and a secondary heat exchanger 8. The primary heat exchanger 7 is disposed in the hot water supply combustion chamber 90 on the upstream side of the combustion exhaust path of the gas burner 4, and the The secondary heat exchanger 8 is disposed within the hot water supply combustion chamber 90 on the downstream side of the combustion exhaust path.

In the hot water supply side circuit 2, a water inlet pipe 12 is connected to the inlet of the secondary heat exchanger 8 in a configuration that supplies tap water. The water inlet pipe 12 includes a thermistor 25 as a water temperature detection unit that detects the temperature of the water passing through the water inlet pipe 12 (that is, the temperature of the water at a position upstream of the heat exchanger in the water pipe), and a A water amount sensor 34 is provided as a water amount detection section that detects the amount of water (that is, the amount of water flowing through the water pipe). A heat exchanger tube 8a of the secondary heat exchanger 8 is connected to the downstream side of the water inlet pipe 12, and further downstream thereof, a heat exchanger tube 8a of the secondary heat exchanger 8 and a heat exchanger tube 7a of the primary heat exchanger 7 are connected. A pipe 20 connecting the two is connected. A heat transfer tube 7a of the primary heat exchanger 7 is connected to this piping 20, and a hot water outlet pipe 10 is connected to the outlet of the primary heat exchanger 7, and a hot water outlet pipe 10 is connected to the outlet of the primary heat exchanger 7. is connected. The hot water tap pipe 10 is provided with a thermistor 26 that detects the temperature of water within the hot water tap pipe 10. In this configuration, the water inlet pipe 12, the heat transfer pipe 8a, the pipe 20, the heat transfer pipe 7a, and the hot water outlet pipe 10 correspond to an example of water pipes, and pass water introduced from a water supply (not shown) provided outside the hot water supply system 1. Functions as a flow path.

The hot water supply side heat exchanger 6 functions so that the primary heat exchanger 7 recovers sensible heat of the combustion exhaust gas, and then the secondary heat exchanger 8 recovers latent heat. Specifically, the primary heat exchanger 7 includes a heat exchanger tube 7a that serves as a water flow path in the primary heat exchanger 7, and the combustion exhaust gas generated by the gas burner 4 is connected to the water passing through the heat exchanger tube 7a. Heat is exchanged by transferring the combustion heat contained therein and transferring sensible heat energy to water. In addition, the secondary heat exchanger 8 is provided with a heat transfer tube 8a that serves as a water flow path in the secondary heat exchanger 8, and the combustion exhaust generated in the gas burner 4 is transferred to the The combustion heat after passing through the heat exchanger 7 is transferred, and the heat is exchanged so that the thermal energy of latent heat is transferred to the water.

A bypass path 14 configured as a water path different from that of the hot water supply side heat exchanger 6 is provided as a water path that bypasses between the water inlet pipe 12 and the hot water outlet pipe 10. The bypass path 14 has a configuration (for example, a configuration that can change steplessly) that can change the bypass path 14 from a closed state in which water flow is blocked to an open state (a state in which the degree of opening is increased compared to the closed state). A bypass valve 32 is provided. In the water inlet pipe 12, a water flow rate control valve 33 is provided upstream of the branch position where the bypass path 14 connects. The water flow control valve 33 includes a motor that controls the rotation angle of the drive shaft in response to instructions from the controller 22, and continuously changes the opening of the water inlet pipe 12 to various degrees between a closed state and a fully open state. It is configured so that it can be done. In this configuration, the water flow control valve 33 functions to adjust the amount of water flowing through the water pipe.

A gas flow path 40 that supplies gas to the gas burner 4 is provided with a gas source solenoid valve 42, a hot water supply gas proportional control valve 44, a hot water supply switching solenoid valve 46, 46, etc. from the upstream side. The gas flow path 40 includes a main flow path 40A whose upstream end is connected to the gas supply source side, and branch flow paths 40B, 40B connected to the downstream end of the main flow path 40A and branched from the main flow path 40A toward each gas burner 4. ...Including. The gas source solenoid valve 42 corresponds to an example of a first solenoid valve, is provided in the main flow path 40A, and switches between an open state in which the main flow path 40A (gas flow path 40) is opened and a closed state in which the main flow path is closed. . When the gas source solenoid valve 42 is in an open state, gas can flow from the upstream side to the downstream side of the gas source solenoid valve 42. When the gas source solenoid valve 42 is in the closed state, gas does not flow from the upstream side to the downstream side of the gas source solenoid valve 42. The hot water supply switching solenoid valves 46, 46, . . . are provided in each branch flow path 40B, 40B, . Each of the hot water supply switching solenoid valves 46, 46, . Switch to . When the hot water supply switching solenoid valve 46 is in an open state, gas can flow from the upstream side to the downstream side of the hot water supply switching solenoid valve 46. When the hot water supply switching solenoid valve 46 is in the closed state, gas does not flow from the upstream side to the downstream side of the hot water supply switching solenoid valve 46.

A switching solenoid valve 53 is provided in the bath side branch flow path 40C from the gas flow path 40 connected to the gas burner 54 (bath side burner). The hot water supply gas proportional control valve 44 and the hot water supply switching solenoid valve 46 function to adjust the amount of gas supplied to the gas burner 4 .

The hot water supply system 1 includes a hot water supply spark plug 35, a hot water supply frame rod 36, a bath spark plug 37, and a bath frame rod 38. The hot water supply frame rod 36 corresponds to an example of a detection section, and functions as a detection section that detects combustion in the gas burner 4 together with the controller 22 described later. The bath frame rod 38 detects combustion in the gas burner 54. The number of hot water supply frame rods 36 may be one, or two or more.

The hot water supply system 1 includes a fan 48 and a fan motor 49. The fan 48 corresponds to an example of a blower, and operates to send air into the hot water supply side heat exchanger 6. The fan 48 is provided below the hot water supply combustion chamber 90, and supplies combustion air to each gas burner 4 (burner) and the gas burner 54 (bath side burner). The fan motor 49 corresponds to an example of a drive unit, and together with the controller 22 described later, starts driving the fan 48 when a blowing start condition is met, and stops driving the fan 48 when a blowing stop condition is met. Functions as a driving part.

In the bath-side circuit 3, the piping 66 includes an outgoing piping 67 for guiding water from the bathtub 60 side to the bath-side heat exchanger 56 side, and an outgoing piping 67 for guiding water from the bath-side heat exchanger 56 side to the bathtub 60 side. It includes a return pipe 68 for guiding, and an intermediate pipe 69 connected to the outgoing pipe 67 and the return pipe 68 and passing through the bath side heat exchanger 56. The bath side heat exchanger 56 includes a bath primary heat exchanger 57 and a bath secondary heat exchanger 58, and functions to transfer heat generated by the gas burner 54 (bath side burner) to the water passing through the piping 66. . The outgoing pipe 67 is provided with a thermistor 64 (bath thermistor) that detects the temperature of the water passing through the circulation pump 62 and the outgoing pipe 67. The circulation pump 62 is a device that causes water in the piping 66 to flow. A dropping pipe 70 branched from the outlet pipe 10 is connected to the return pipe 68, and the dropping pipe 70 is provided with a hot water supply electromagnetic valve 72 and a dropping water amount sensor 74. The drop pipe 70 serves as a path for passing hot water from the hot water supply side passageway of the hot water supply side circuit 2 to the piping 66 (circulation path) of the bath side circuit 3.

The hot water supply system 1 is provided with a controller 22 shown in FIGS. 1 and 2. The controller 22 shown in FIG. 2 is configured as, for example, a control unit 22A configured as a known microcomputer or the like, a memory 22B configured as a known semiconductor memory, etc., and an interface for communicating with the outside. It includes a communication section 22C. The controller 22 is configured to be able to acquire signals from various sensors provided in the hot water supply side circuit 2 and the bath side circuit 3, and can control various actuators provided in the hot water supply side circuit 2 and the bath side circuit 3. .

The controller 22 corresponds to an example of a detection section, a control section, a determination section, and a drive section. The controller 22 can perform a first control in which the gas source solenoid valve 42 is closed and the hot water supply switching solenoid valves 46, 46, . . . are opened when the combustion termination condition is satisfied. During the first control, when the gas source solenoid valve 42 is normally closed (when the gas flow in the gas flow path 40 is blocked), gas is not transferred from the outside of the hot water supply system 1 to the gas burner 4. Not supplied. The controller 22 can perform a second control in which the hot water supply switching solenoid valves 46, 46, . . . are closed and the gas source solenoid valve 42 is opened when the combustion termination condition is satisfied. During the second control, when the hot water supply switching solenoid valves 46, 46, etc. are normally closed (when the gas flow in the gas flow path 40 is blocked), the gas burner is connected from the outside of the hot water supply system 1. No gas is supplied to 4. The controller 22 can perform a first determination process of determining whether combustion in the gas burner 4 is detected based on a signal from the hot water supply frame rod 36 during the first control. The controller 22 can perform a second determination process to determine whether combustion in the gas burner 4 is detected based on the signal from the hot water supply frame rod 36 during the second control. The controller 22 selectively performs the first control of the first control and the second control when a predetermined condition (at least one of the time condition and the equipment condition) is satisfied when the combustion termination condition is satisfied. . In this case, the second control is not performed. Further, the controller 22 performs the second control of the first control and the second control if a predetermined condition (at least one of the time condition or the equipment condition) is not satisfied when the combustion termination condition is satisfied. conduct. In this case, the first control is not performed.

Among the above time conditions and the above equipment conditions, the above time conditions are time conditions such as "a predetermined time has arrived" and "a predetermined action (for example, a fire extinguishing action) has been performed in a predetermined time zone." "A certain amount of time has passed since the last fire extinguishment," "A certain amount of time has elapsed since the last time the fan 48 stopped operating," and "A certain amount of time has elapsed since the last self-diagnosis was completed." The elapsed time condition may be, for example, "combustion of the gas burner 4 was started in 2008."

Of the above time conditions and the above equipment conditions, the above equipment conditions specifically include "the predetermined equipment installed in the hot water supply system 1 is in a predetermined state" or "the predetermined equipment installed in the hot water supply system 1 is in a predetermined state". ``The conditions for achieving a predetermined state have been met.'' Although the predetermined devices are not particularly limited, they include, for example, the gas burner 4, the fan 48, the water amount sensor 34, and the like. The device condition may be "the fulfillment of a condition for starting the operation of a predetermined device" or "the fulfillment of a condition for prohibiting the operation of a predetermined device", It may be that "a condition for suspending the operation of a predetermined device for a certain period of time has been met" or it may be that "a condition for terminating the operation of a predetermined device has been met". Further, the device condition may be "the operation of a predetermined device has finished", "the operation of a predetermined device has started", or "the operation of a predetermined device has started". It may also mean that the operation of the person is prohibited. Specifically, the equipment condition may be a condition under which cooling or heating suppression of the heat exchanger is performed depending on the establishment of the equipment condition. More specifically, the device condition may be such that the fan 48 is driven in accordance with the establishment of the device condition, and the hot water supply side heat exchanger 6 is cooled by the drive of the fan 48. Alternatively, the device condition may be such that the ignition of the gas burner 4 is prohibited for a certain period of time depending on the establishment of the device condition, and when such ignition suppression continues for a certain period of time, the hot water supply side heat exchanger 6 is cooled or suppressed from heating. It may be a condition. In the following description, predetermined device conditions among these will be exemplified and explained.

Moreover, the controller 22 performs the first control before the fan 48 is driven by the fan motor 49 in accordance with the establishment of the ventilation start condition.

In this embodiment, the self-diagnosis condition corresponds to an example of the ventilation start condition. The self-diagnosis conditions are conditions that trigger the execution of self-diagnosis, and correspond to an example of device conditions. The self-diagnosis includes processing for detecting an abnormality in the hot water supply system 1 (for example, an abnormality in the driving of the fan 48). Specifically, when a predetermined self-diagnosis condition is established, the controller 22 drives the fan 48 for a certain period of time to perform an air blowing operation, and detects the current, voltage, power, and temperature at a predetermined position within the certain period of time. etc., is within the normal range. For example, when the above self-diagnosis condition is satisfied, the controller 22 drives the fan motor 49 for a certain period of time, and during the certain period of time, the controller 22 drives the fan motor 49 in a predetermined conductive path (for example, a conductive path that supplies current to the fan motor 49) in the hot water supply system 1. ) can perform a self-diagnosis operation to determine whether the current flowing through the current exceeds a threshold, and if it does not exceed the threshold, it is determined to be a normal current, and if it exceeds the threshold, it is determined to be an abnormal current. . Alternatively, if the above self-diagnosis condition is satisfied, the controller 22 drives the fan motor 49 for a certain period of time, determines that the power consumption of the fan motor 49 is normal if it does not exceed a certain value during this certain period, and then drives the fan motor 49 to a certain value. A self-diagnosis may be performed such that if the value exceeds this value, it is determined that there is an abnormality. The self-diagnosis condition can be, for example, "combustion of the gas burner 4 is started for the first time after a predetermined period of time (for example, 24 hours) has passed since the previous self-diagnosis was completed." Note that the self-diagnosis conditions are not limited to this example, and may be other conditions (for example, the gas burner 4 has been burned a predetermined number of times since the previous self-diagnosis was completed, or a predetermined operation has been performed on the hot water supply system 1). (for example, the combustion of the gas burner 4 is started for the first time after the combustion is started).

As shown in FIG. 2, the plurality of remote controllers 80 are arranged in a configuration that allows them to communicate with the controller 22 (detection section, control section, determination section, drive section). In the example of FIGS. 1 and 2, the plurality of remote controllers 80 include a first remote controller 81 provided in a bathroom and a second remote controller 82 provided in a location other than the bathroom (for example, the kitchen). .

As shown in FIG. 2, the first remote controller 81 includes a control section 81A configured as a known microcomputer or the like, a display section 81B configured as a liquid crystal display device, etc., and a plurality of known switches such as push buttons. A communication unit 81D that communicates with the controller 22 and the second remote controller 82, and an audio output unit 81E that includes a speaker that outputs audio. The operating section 81C is configured by a plurality of operating sections, and is used for input operations for switching the power on/off state, input operations for switching the set temperature, and the like.

The second remote controller 82 is similar, and includes a control section 82A configured as a known microcomputer or the like, a display section 82B configured as a liquid crystal display device, etc., and a plurality of known switches such as push buttons. It includes an operation section 82C, a communication section 82D for transmitting signals generated by the second remote controller 82 to the controller 22, and an audio output section 82E including a speaker for outputting audio.

The second remote controller 82 has the same or simplified configuration as the first remote controller 81, and can be set in the same way as the first remote controller 81. The on/off states of both remote controllers 80 are linked together. In both remote controllers 80, the contents set on one are reflected on each other.

(Hot water supply control)
The controller 22 performs hot water supply control according to the flow shown in FIG. 3, for example. After the power is turned on, the controller 22 executes the hot water supply control shown in FIG. 3, and determines in S11 whether or not combustion start conditions are satisfied. The combustion start condition may be, for example, ``the amount of water detected by the water amount sensor 34 (for example, the amount of water per unit time) (hereinafter also simply referred to as ``the amount of water''), or may be another condition. may be the condition. The process remains in a standby state until the combustion start condition is satisfied, and the determination of No is repeated in S11.

If the controller 22 determines that the combustion start condition is satisfied (S11: Yes), it executes the ignition process in S12. The controller 22 performs the following process in the ignition process (S12). The controller 22 operates an igniter (not shown) to cause the hot water supply spark plug 35 to discharge. Further, the controller 22 opens the gas source solenoid valve 42 and the hot water supply switching solenoid valves 46, 46, . . . , sets the hot water supply gas proportional control valve 44 to a slow ignition operation, and ignites the gas burner 4. Thereafter, the controller 22 determines whether combustion of the gas burner 4 is detected by the hot water supply flame rod 36, and if it is determined that combustion is detected, terminates the slow ignition operation and starts the ignition process (S12). finish.

After the ignition process (S12) is completed, the controller 22 determines in S13 whether the combustion termination condition is satisfied. The combustion end condition may be, for example, "the amount of water detected by the water amount sensor 34 (for example, the amount of water per unit time) is less than a predetermined threshold", or it may be another condition (the combustion end condition for the hot water supply system 1). (for example, that a predetermined operation instructing the end of combustion has been performed, or that a predetermined stop condition has been met as a condition for stopping combustion, etc.). When the controller 22 determines that the combustion end condition is not satisfied (S13: No), it is determined in S14 whether the change condition is satisfied. The change conditions include, for example, the inlet water temperature detected by the thermistor 25 (hereinafter also simply referred to as "inlet water temperature"), the set temperature set by the remote controller 80 (hereinafter also simply referred to as "set temperature"), and the water flow sensor. It may be that at least one of the amounts of water (for example, the amount of water per unit time) detected by 34 has undergone a change that satisfies a predetermined criterion, or it may be another condition.

If the controller 22 determines that the change condition is not satisfied (S14: No), it performs feedback temperature control in S15. In feedback temperature control, the controller 22 generates an output ( combustion output) is calculated, and the rotational speed of the fan 48 and the opening degree of the hot water supply gas proportional control valve 44 are adjusted. Further, if further adjustment of increase or decrease in output is required, the controller 22 switches one of the four combustion stages by switching the opening and closing of the hot water supply switching solenoid valves 46, 46, . . . . When the feedback temperature control (S15) is completed, the controller 22 returns to the process of S13. That is, the controller 22 repeatedly executes the feedback temperature control (S15) until the combustion end condition is satisfied or the change condition is satisfied.

If the controller 22 determines that the change condition is satisfied (S14: Yes), it performs feedforward temperature control in S16. In feedforward temperature control, the controller 22 calculates the required combustion output based on the temperature difference between the incoming water temperature and the set temperature and the amount of water. Then, the controller 22 sets the combustion stage corresponding to the calculated output, and adjusts the rotation speed of the fan 48 and the opening degree of the hot water gas proportional control valve 44. When the feedforward temperature control (S16) is completed, the controller 22 returns to the process of S13.

When the controller 22 determines that the combustion end condition is satisfied (S13: Yes), the controller 22 determines that the self-diagnosis condition (for example, "After a predetermined period of time (for example, 24 hours) has passed since the previous self-diagnosis was completed, It is determined whether the condition "combustion of the gas burner 4 is started first" is satisfied.

When the controller 22 determines that the self-diagnosis condition is satisfied in S17 (S17: Yes), the controller 22 executes the first control described above in S20. Specifically, in S20, the controller 22 closes the gas source solenoid valve 42 and opens the hot water supply switching solenoid valves 46, 46, . In other words, the controller 22 switches the gas source solenoid valve 42 to the closed state while maintaining the hot water supply switching solenoid valves 46, 46, . . . in the open state. When some of the hot water supply switching solenoid valves 46, 46, etc. are in the open state and the rest are in the closed state, the controller 22 maintains the open state in the open state and changes the closed state to the closed state. Those that have been closed will remain closed.

During the first control (S20), the controller 22 performs the first determination process described above in S21. That is, the controller 22 determines whether combustion in the gas burner 4 is detected based on the signal from the hot water supply frame rod 36. When the controller 22 determines that combustion in the gas burner 4 is detected (S21: Yes), the controller 22 determines that the gas source solenoid valve 42 is abnormal, and notifies the user by, for example, the display section 82B, the audio output section 82E, etc. Notify the occurrence of an abnormality. After notifying the occurrence of an abnormality, or when determining that combustion in the gas burner 4 is not detected, the controller 22 ends the first determination process (S21).

After the first determination process (S21), the controller 22 closes the gas source solenoid valve 42 and the hot water supply switching solenoid valves 46, 46, . . . in S22. That is, the controller 22 switches all the hot water supply switching solenoid valves 46, 46, . . . to the closed state while maintaining the gas source solenoid valve 42 in the closed state.

After the controller 22 closes the gas source solenoid valve 42 and the hot water supply switching solenoid valves 46, 46, . . ., the controller 22 performs the above-described self-diagnosis in S23. In other words, the controller 22 drives the fan 48 for a certain period of time to perform the air blowing operation, and determines whether the current, voltage, power, temperature, etc. at a predetermined position are within the normal range within the certain period of time. Operate. After that, the controller 22 returns to S11.

If the controller 22 determines in S17 that the self-diagnosis condition is not satisfied (S17: No), it performs the second control described above in S30. That is, in S30, the controller 22 closes all the hot water supply switching solenoid valves 46, 46, etc., and opens the gas source solenoid valve 42. In other words, the controller 22 switches the open hot water supply switching solenoid valves 46, 46, . . . to the closed state while maintaining the gas source solenoid valve 42 in the open state.

During the second control (S30), the controller 22 performs the second determination process described above in S31. That is, the controller 22 determines whether combustion in the gas burner 4 is detected based on the signal from the hot water supply frame rod 36. When the controller 22 determines that combustion in the gas burner 4 has been detected (S31: Yes), the controller 22 determines that the gas source solenoid valve 42 is abnormal, and notifies the user by, for example, the display section 82B, the audio output section 82E, etc. Notify the occurrence of an abnormality. After notifying the occurrence of an abnormality, or when determining that combustion in the gas burner 4 is not detected, the controller 22 ends the second determination process (S31).

After the second determination process (S31), the controller 22 closes the gas source solenoid valve 42 and the hot water supply switching solenoid valves 46, 46, . . . in S32. That is, the controller 22 switches the gas source solenoid valve 42 to the closed state while maintaining the hot water supply switching solenoid valves 46, 46, . . . in the closed state. After that, the controller 22 returns to S11.

The following description relates to an example of the effect of this configuration.
The hot water supply system 1 can detect the presence or absence of an abnormality in the gas source solenoid valve 42 by performing the first determination process, and can detect the presence or absence of an abnormality in the hot water supply switching solenoid valves 46, 46, etc. by performing the second determination process. can be detected.

However, when the hot water supply system 1 performs the first control, the hot water supply switching solenoid valves 46, 46, etc. remain open, so even after the gas source solenoid valve 42 is closed, the gas source solenoid valves 46, 46, etc. remain open. Combustion in the gas burner 4 continues until the gas remaining downstream of the valve 42 is completely burned. Therefore, in the hot water supply system 1, when the first control is performed, excess heat is likely to be added to the inside of the water pipe, and heated water is likely to remain inside the water pipe. Then, when the next combustion start condition is met with heated water remaining in the water pipe, the temperature of the heated remaining water is detected as the hot water temperature, and feedback temperature control is performed based on this hot water temperature. In this case, it may take some time to bring the hot water temperature close to the set temperature.

However, this hot water supply system 1 performs the first control before the air blowing operation. Therefore, even if heated water remains inside the water pipe due to the first control being performed, the temperature of the water remaining inside the water pipe decreases due to the air blowing operation by the fan 48. Therefore, in this hot water supply system 1, even if heated water remains inside the water pipe due to the first control, the next combustion is performed after lowering the water temperature of the heated remaining water. be able to.

In particular, this hot water supply system 1 performs the first control in accordance with the timing of self-diagnosis accompanied by air blowing operation. For this reason, in this hot water supply system 1, compared to a configuration in which a separate air blowing operation is performed to lower the temperature of the water that has been superheated by the first control, the heated water remains inside the water pipe and is used for the next operation. It is possible to efficiently suppress the occurrence of a situation in which combustion occurs.

<Other embodiments>
The present disclosure is not limited to the embodiments described above and illustrated in the drawings. For example, the features of the embodiments described above or below can be combined in any combination without contradicting each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. Furthermore, the embodiment described above may be modified as follows.

In the embodiment described above, the detection unit is the hot water supply frame rod 36, but other configurations may be used as long as the configuration can detect combustion of the gas burner 4. For example, the detection unit may detect any one of heat, light, and electrical characteristics of the combustion flame. As a specific example, the hot water supply system 1 may be configured to include a thermocouple that detects the combustion heat of the gas burner 4, and this thermocouple may be used as the detection section. As yet another example, the hot water supply system 1 may be configured to include an optical sensor classified into three types (ultraviolet type, visible light type, infrared type) depending on the wavelength to be detected, and this optical sensor may be used as the detection section.

In the embodiments described above, the predetermined device conditions are used as the self-diagnosis conditions, but other conditions may be used. For example, the equipment condition may be that the number of executions of a predetermined device (e.g., fan, gas burner, etc.) has reached a certain value since the previous completion of the first control, and The device condition may be that the cumulative execution time of the device has reached a certain value. Moreover, the hot water supply system 1 may set time conditions instead of equipment conditions. The time condition may be, for example, "after a predetermined time when the hot water supply system 1 is used less frequently." Alternatively, the time condition may be "that a certain period of time has passed since the previous completion of the first control". Moreover, the hot water supply system 1 may be configured to set both device conditions and time conditions, and perform the first control when either condition is satisfied.

In the embodiment described above, the blowing operation performed after the first control is defined as the "blowing operation during self-diagnosis," but it does not have to be the blowing operation during self-diagnosis.

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

1...Hot water system 4...Gas burner (burner)
6...Hot water supply side heat exchanger (heat exchanger)
7a, 8a...Heat transfer tube (water pipe)
10... Hot water pipe (water pipe)
12... Water inlet pipe (water pipe)
20...Piping (water pipe)
22... Controller (control unit, detection unit, determination unit, drive unit)
36…Hot water supply frame rod (detection part)
40...Gas flow path 42...Gas source solenoid valve (first solenoid valve)
46...Hot water supply switching solenoid valve (second solenoid valve)
48...Fan (blower)
49...Fan motor (drive part)

Claims (3)

A water pipe that passes water introduced from the outside,
A burner that burns combustion gas to generate exhaust gas,
a gas flow path that is a flow path for supplying the combustion gas to the burner;
a first solenoid valve that switches between an open state in which the gas flow path is opened and a closed state in which the gas flow path is closed;
a second solenoid valve that switches between an open state in which the gas flow path is opened and a closed state in which the gas flow path is closed at a position downstream of the first solenoid valve;
a heat exchanger that is provided in the middle of the water pipe and transfers heat of the exhaust gas to water passing through the water pipe;
a first control in which the first solenoid valve is closed and the second solenoid valve is opened when the combustion termination condition is met; and a first control in which the second solenoid valve is closed when the combustion termination condition is met. a control unit that performs a second control of opening the first electromagnetic valve while
a detection unit that detects combustion in the burner;
a first determination process for determining whether combustion in the burner is detected by the detection unit during the first control; and combustion in the burner is detected by the detection unit during the second control. a determination unit that performs a second determination process of determining whether or not;
Equipped with
The control unit performs the first control when a predetermined time condition or device condition is satisfied when the combustion end condition is established, and performs the second control when the combustion end condition is not satisfied. a blower that blows air into the heat exchanger;
a drive unit that starts driving the blower when a blowing start condition is met and stops driving the blower when a blowing stop condition is met;
Equipped with
The hot water supply system according to claim 1, wherein the control section performs the first control before the blowing operation in which the drive section drives the blower in response to establishment of the blowing start condition. The drive unit drives the blower when a self-diagnosis condition is satisfied;
The hot water supply system according to claim 2, wherein the control unit performs the first control before the air blowing operation in response to establishment of the self-diagnosis condition.

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