JP6830400B2 - Ground fault detector - Google Patents

Description

The present invention relates to a device for detecting a ground fault of an energizing wire connected to a plurality of electronic components included in various devices such as a water heater.

In various various devices, a plurality of energizing wires (so-called energizing wires constituting a harness) for energizing electric power for operating a plurality of electronic components are arranged inside the housing. In this type of equipment, the covering tube (insulated tube) of any of the energizing wires is damaged during manufacturing, installation, maintenance and inspection, or due to vibration, impact, etc. acting from the outside. Then, a phenomenon in which the current-carrying wire is electrically conducted to the conductor portion of the housing, that is, a so-called ground fault may occur.

When such a ground fault occurs, an abnormal current may flow through the device, or the device may malfunction or be erroneously detected. Therefore, a device for detecting the occurrence of the ground fault has been conventionally proposed. (See, for example, Patent Documents 1 to 3 and the like).

Japanese Unexamined Patent Publication No. 5-336649 Japanese Unexamined Patent Publication No. 11-271378 Japanese Unexamined Patent Publication No. 2013-199874

In a device equipped with a large number of electronic components, the number of current-carrying wires that can cause a ground fault is large. Therefore, when a ground fault occurs, not only the occurrence of the ground fault is detected, but also the ground fault occurs on any of the current-carrying wires. It is desirable to be able to identify as much as possible whether it has occurred.

However, in the conventional technique found in Patent Document 1 and the like, it is not possible to identify the energizing line in which the ground fault has occurred from a large number of energizing lines.

For this reason, conventionally, with a device equipped with a large number of current-carrying wires that can cause a ground fault, when a ground fault occurs, a trader or the like has to identify the current-carrying wire in which the ground fault has occurred from a large number of current-carrying wires. You will need it. And there is a disadvantage that a large amount of man-hours are likely to be required for the work.

The present invention has been made in view of such a background, and an object of the present invention is to provide a ground fault detecting device capable of identifying an energized wire in which a ground fault has occurred as much as possible when a ground fault occurs. And.

First, a reference invention related to the present invention will be described. The ground fault detection device of the reference invention is a device including a housing in which energizing wires for energizing a plurality of electronic components are arranged inside in order to achieve the above object, and is eventually a conductor portion of the housing. When a ground fault occurs, which is a phenomenon in which the current-carrying wire for energizing the electronic component is conducted, it is specified which electronic component is the current-carrying wire for which the ground fault has occurred. It is a ground fault detection device that has the function of
When the ground fault occurs, the ground fault current, which is the current flowing through the current-carrying wire and the housing in which the ground fault has occurred, is detected, and an output corresponding to the magnitude of the ground fault current is generated. Ground fault current detector and
A wire that identifies the energizing line in which the ground fault has occurred based on at least one of the magnitude of the ground fault current indicated by the output of the ground fault current detector and the change pattern of the magnitude of the ground fault current. It is characterized by including an electric wire specific portion ( first reference invention).

Here, in a device including a plurality of electronic components, the magnitude of the power supply voltage of each electronic component, the change pattern of the energizing current of each electronic component, the impedance of the energizing circuit of each electronic component, and the like are determined by the electronic component. In many cases, it differs depending on the type of.

Therefore, when a ground fault occurs in the current-carrying wire corresponding to a certain electronic component (the current-carrying wire for energizing the electronic component), the magnitude of the ground fault current indicated by the output of the ground fault current detector, or In many cases, the change pattern is characteristic of which electronic component the current-carrying wire in which the ground fault has occurred corresponds to.

Therefore, the current-carrying wire identification unit is based on at least one of the magnitude of the ground fault current indicated by the output of the ground fault current detector and the change pattern of the magnitude of the ground fault current. Identify the energizing line in which.

Thereby, according to the first reference invention, it is possible to identify the current-carrying wire in which the ground fault has occurred as much as possible.

In the first reference invention, in the current-carrying wire specifying unit, the magnitude of the ground fault current indicated by the output of the ground fault current detector when the ground fault occurs is in a plurality of preset ranges. Judgment result of which range of the change pattern belongs to, and judgment result of which type of change pattern among a plurality of preset types of change patterns is the change pattern of the magnitude of the ground fault current. Based on the determination result of at least one of the above, it may be configured to identify the current-carrying wire in which the ground fault has occurred ( second reference invention).

According to this, it is possible to classify and identify as many types of energizing wires as possible in which a ground fault has occurred.

In the first reference invention or the second reference invention, the energizing line specifying unit uses the fluctuation frequency of the magnitude of the ground fault current indicated by the output of the ground fault current detector as an index representing the change pattern. , The current-carrying wire in which the ground fault has occurred may be specified ( third reference invention).

That is, the plurality of electronic components often include a plurality of electronic components having different frequencies of energization. In this case, by using the fluctuation frequency of the magnitude of the ground fault current indicated by the output of the ground fault current detector as an index representing the change pattern, the energized line in which the ground fault has occurred is used as the fluctuation of the ground fault current. It is possible to classify and identify based on the frequency.

In the first to third reference inventions, of the energizing wires for each of the plurality of electronic components, at least a part of the plurality of energizing wires, which of the plurality of energizing wires is used. In the case of specifying whether or not a ground fault has occurred in, for each of the plurality of current-carrying wires, the process of determining whether or not a ground fault has occurred in the current-carrying wires is performed through the plurality of lines. It may be configured to perform on the wires in a predetermined order ( 4th Reference Invention).

In the fourth reference invention, executing the determination process on the plurality of energized wires in a predetermined order is a predetermined first of the plurality of energized wires. The determination process is first executed for the first energized line, the determination process is executed second for the predetermined second energized line, and the third energized line is executed for the predetermined third energized line. It means that the determination process is executed in order in such a manner that the determination process is executed.

According to the fourth reference invention, the determination process of whether or not a ground fault has occurred is performed on each of the plurality of energized wires in a suitable order in order to improve the reliability of the determination process. It becomes possible to execute. As a result, the reliability of the specific result of the current-carrying wire in which the ground fault has occurred can be improved.

In the first to fourth reference inventions, the current-carrying wire specifying unit determines whether or not a ground fault has occurred in a predetermined current-carrying wire among the current-carrying wires for each of the plurality of electronic components. In addition, the electronic component corresponding to the predetermined energizing line is operated, and the magnitude of the ground fault current indicated by the output of the ground fault current detector in the operating state and the change pattern of the magnitude of the ground fault current. Based on at least one of the above, it may be configured to determine whether or not a ground fault of the predetermined current-carrying wire has occurred ( Fifth Reference Invention).

Here, for a certain electronic component, when a ground fault of the energizing wire corresponding to the electronic component occurs in the operating state of the electronic component, the magnitude of the ground fault current indicated by the output of the ground fault current detector. And at least one of the change patterns of the magnitude of the ground fault current may be characteristic.

Therefore, according to the fifth reference invention, when a ground fault of the energizing wire corresponding to such an electronic component occurs, it is possible to appropriately identify the energizing wire.

In the first to fifth reference inventions, the energizing line specifying unit is described in different modes depending on whether the device is in a standby state in which the device is not being operated or in an operating state in which the device is being operated. It may be configured to identify the energizing wire in which the ground fault has occurred ( 6th Reference Invention).

That is, when a ground fault occurs in the energizing wire corresponding to any of the electronic components, the magnitude of the ground fault current indicated by the output of the ground fault current detector or its change pattern is the standby state of the device. In many cases, it differs depending on the operating condition. Therefore, according to the sixth reference invention, it is possible to improve the reliability of the specific result of the current-carrying wire in which the ground fault has occurred .
Next, to explain the present invention, the ground fault detection device of the present invention is a device including a housing in which energizing wires for energizing a plurality of electronic components are internally arranged in order to achieve the above object. When a ground fault occurs, which is a phenomenon in which the conductor portion of the housing and the energizing wire for energizing any of the electronic components are conducted, the energizing wire in which the ground fault occurs energizes which electronic component. It is a ground fault detection device that has a function to identify whether it is a current-carrying wire.
When the ground fault occurs, it has a resistance to flow a ground fault current, which is a current flowing through the current-carrying wire and the housing in which the ground fault has occurred, and the resistance is generated according to the ground fault current. A ground fault current detector that detects the ground fault current by the voltage to be generated and generates a ground fault detection voltage that is an output voltage corresponding to the ground fault current.
The ground fault detection voltage of the ground fault current detector and the fluctuation frequency of the ground fault detection voltage include at least a fluctuation frequency, and a current supply line specifying unit for identifying the current supply line in which the ground fault has occurred is provided. And
When the energizing line specifying unit identifies the energizing line in which the ground fault has occurred based on the fluctuating frequency, the determination result of which of a plurality of preset frequencies the fluctuating frequency is. Based on the above, it is characterized in that it is configured to identify the current-carrying wire in which the ground fault has occurred.

The figure which shows outline the composition of the main part of the water heater as the apparatus of one Embodiment of this invention. The figure which shows the connection structure of the electronic circuit unit and the electronic component provided in the water heater of an embodiment. The figure which shows the connection structure of the electronic circuit unit and the electronic component provided in the water heater of an embodiment. The figure which shows the circuit structure of the ground fault detection circuit shown in FIG. The figure for demonstrating the operation of the ground fault detection circuit at the time of the occurrence of a ground fault. The figure which illustrates the range of the magnitude of the voltage output by the ground fault detection circuit in the standby state of the water heater of an embodiment. The figure which illustrates the range of the magnitude of the voltage output by the ground fault detection circuit at the time of operation of the electronic component of the water heater of an embodiment. The flowchart which shows the processing of the microcomputer provided in the water heater of an embodiment. The flowchart which shows the processing of the microcomputer provided in the water heater of an embodiment. The flowchart which shows the processing of the microcomputer provided in the water heater of an embodiment. The flowchart which shows the processing of the microcomputer provided in the water heater of an embodiment.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 11. With reference to FIG. 1, in the present embodiment, the device 1 targeted for ground fault detection is, for example, a bath water heater with a hot water heating function. FIG. 1 schematically shows a main configuration of this device 1 (hereinafter, simply referred to as a water heater 1).

The water heater 1 has a housing 2 installed outdoors. The housing 2 is a casing in which the main components of the water heater 1 are mounted, and the whole or a part thereof is made of a conductor such as metal. Then, the entire housing 2 or the conductor portion is grounded to the ground side via the grounding cable 2g.

Inside the housing 2, a plurality of burners (hot water supply burner, bath / heating burner) and a plurality of heat exchangers (hot water supply heat exchanger, bath / heating heat exchanger), which are not shown, are housed. Has been done. Then, a fuel pipe 3 that supplies fuel gas to the burner, a water supply pipe 4 that introduces hot water for heating (tap water, etc.) into the housing 2, and a hot water supply place such as a kitchen or bathroom for heated hot water (hot water). The hot water supply pipe 5 to supply the hot water, the bath pipes 6a and 6b for flowing the bath water (hot water), and the hot water pipes 7a and 7b for flowing the hot water for heating extend from the inside of the housing 2.

Further, an electronic circuit unit 10 that functions as a control device that controls the operation of the water heater 1 is housed inside the housing 2. The electronic circuit unit 10 has a substrate 11 fixed to the housing 2 via a bracket or the like (not shown). A wiring pattern (not shown) is formed on the substrate 11, and various circuit elements described later are mounted on the substrate 11.

Further, a plurality of harnesses 12, 12, ... Are connected to the board 11 via connectors 13, respectively, and a power cord 14 and a ground wire for receiving the power of a commercial power source as the power source of the water heater 1. 15 is connected via the connector 16.

The power cord 14 is connected to a commercial power outlet via an earth leakage breaker (not shown). Further, the ground wire 15 is grounded to the conductor portion of the housing 2, and by extension, is grounded to the ground side via the housing 2.

Each harness 12 is a bundle of a plurality of energizing wires, and each electrically connects a plurality of electronic components described later to the substrate 11. In this case, each harness 12 that connects the electronic components arranged in the housing 2 and the substrate 11 is arranged in the housing 2. Further, each harness 12 (for example, a harness 12d described later) that connects an electronic component arranged outside the housing 2 to the board 11 is a housing 2 from a connector 13 on the board 11 side to a predetermined lead-out portion of the housing 2. It is arranged inside, and is further led out from the lead-out portion to the outside of the housing 2.

In the present embodiment, a typical circuit element mounted on the board 11 and a typical electronic component connected to the board 11 via the harness 12 will be described below with reference to FIGS. 2 and 3. ..

As shown in FIGS. 2 and 3, the water heater 1 of the present embodiment drives, for example, an electric valve (three-way valve in a water passage, etc.) (not shown) as an electronic component connected to the substrate 11 via a harness 12. A plurality of stepping motors 21, 21, ..., a thermal fuse 22 that breaks when a predetermined portion in the housing 2 becomes overheated, and all burners in the housing 2 (hot water supply burner, bath / heating burner). ), A gas main valve 23 that opens and closes a common fuel supply path (the fuel pipe 3), and a plurality of gas solenoid valves 24, 24 that open and close the fuel supply path for each burner on the downstream side of the gas main valve 23. , ..., A plurality of thermistas 25 and 25 for detecting the hot water supply temperature and the like, a water amount sensor 26 for detecting the water supply flow rate in the water supply pipe 4, and being supplied to the hot water supply when the hot water is filled. A hot water amount sensor 27 that detects the amount of hot water, which is the flow rate of hot water, a floor heating remote control 28 for operating the floor heating device, a bathroom heating remote control 29 for operating the bathroom heating device, and hot water in the bathtub. It includes a hot water beam valve 30 that opens and closes a flow path for beams, and a water replenishment valve 31 that opens and closes a water passage that replenishes the flow path of hot water for heating.

In the present embodiment, the stepping motors 21, 21, ... Are connected to the substrate 11 via the harness 12a and the connector 13a, and the temperature fuse 22, the gas source valve 23, and the gas solenoid valves 24, 24, ... Are harnesses. It is connected to the substrate 11 via the 12b and the connector 13b.

Further, the thermistas 25 and 25, the water amount sensor 26, and the hot water amount sensor 27 are connected to the substrate 11 via the harness 12c and the connector 13c, and the floor heating remote controller 28 and the bathroom heating remote controller 29 are connected to the harness 12d and the connector 13d. The hot water valve 30 and the water replenishment valve 31 are connected to the substrate 11 via the harness 12e and the connector 13e.

Here, each of the harnesses 12a to 12e is a harness in which at least a part thereof is arranged in contact with or close to the conductor portion of the housing 2. Therefore, in each of the harnesses 12a to 12e, any of the energizing wires included in the harness is electrically conducted with respect to the conductor portion of the housing 2 due to biting, damage, etc. of the covering tube (not shown). A condition, that is, a ground fault condition can occur.

In the present embodiment, the electronic components shown in FIGS. 2 and 3 are typically exemplified as the electronic components included in the water heater 1. However, the electronic components included in the water heater 1 may include electronic components other than those shown in FIGS. 2 and 3. For example, the electronic component may include a substrate other than the substrate 11. Alternatively, any of the electronic components shown in FIGS. 2 and 3 may not be provided. Further, the combination of the type of electronic component and the harness, or the layout of the connector on the substrate 11 is not limited to the mode shown in FIGS. 2 and 3.

Further, in the water supply device 1 of the present embodiment, as circuit elements mounted on the substrate 11, for example, as shown in FIG. 2, a microcomputer (microcomputer) 41 that executes control processing related to operation control of the water supply device 1 is used. A power supply circuit 42 that generates a DC power supply voltage of a predetermined voltage for operating circuit elements such as electronic components and microcomputers from the power of a commercial power supply (AC power), and the stepping motor 21 in response to a control command of the microcomputer 41. , 21, ..., And a plurality of motor drive circuits 43, 43, ... That energize each of the drive currents, and energization control (and by extension, each of the gas main valve 23 and each gas electromagnetic valve 24, respectively, according to the control command of the microcomputer 41. , The electromagnetic valve drive circuit 44 that controls the opening and closing of the gas main valve 23 and each gas electromagnetic valve 24), and the gas main valve 23 and each gas electromagnetic valve 24 are forced to be energized when the thermal fuse 22 is disconnected. When a ground fault occurs in the forced valve closing circuit 45 (which forcibly closes the gas main valve 23 and each gas electromagnetic valve 24) and the current-carrying wire of any of the harness 12s. The ground fault detection circuit 46 that detects the above, the temperature detection signal by each thermista 25, the water flow rate detection signal by the water amount sensor 26, and the hot water amount detection signal by the hot water amount sensor 27, and these A detection circuit 47 that inputs detection information to the microcomputer 41, a communication circuit 48 that relays communication between each of the floor heating remote control 28 and the bathroom heating remote control 29, and the microcomputer 41, and the hot water according to a control command of the microcomputer 41. The hot water valve drive circuit 49 that controls the energization of the beam valve 30 (and thus the opening and closing control of the hot water valve 30) and the energization control of the refill valve 31 (and thus the opening and closing of the refill valve 31) in response to the control command of the microcomputer 41. It includes a refill valve drive circuit 50 that performs control).

The input side (primary side) of the power supply circuit 42 is connected to the power cord 14 via a connector 16, and the power (AC power) of a commercial power source is input from the power cord 14. The power supply circuit 42 includes a power conversion circuit (switching type power conversion circuit) having a known configuration including a transformer (not shown), and the power conversion circuit generates and outputs a DC power supply voltage of a predetermined voltage. It is configured as follows. ..

Here, the DC power supply voltage generated by the power supply circuit 42 is three types of DC voltage of 5V, 12V, and 24V in this embodiment. 5V is the operating voltage of the microcomputer 41 and each thermistor 25, and 12V is the stepping motor 21, the temperature fuse 22, the gas source valve 23, the gas electromagnetic valve 24, the water amount sensor 26, the hot water amount sensor 27, and the hot water beam. The operating voltage of the valve 30 and the refill valve 31, 24V, is the operating voltage of the floor heating remote control 28 and the bathroom heating remote control 29.

The wiring pattern of the board 11 is a housing grounding potential portion 61 grounded to the housing 2 via the grounding wire 15 and a power supply circuit as a reference potential portion of the power input from the commercial power supply to the power supply circuit 42. 5V, 12V with respect to the secondary side ground 62 as the reference potential portion of the DC power supply voltage generated by 42 (reference potential portion on the output side (secondary side) of the power supply circuit 42) and the secondary side ground 62. , And a 5V potential portion 63, a 12V potential portion 64, and a 24V potential portion 65 to which a 24V DC power supply voltage is applied, respectively.

In this case, in the power supply circuit 42, the housing ground potential portion 61 and the secondary side ground 62 are electrically isolated from each other via a transformer. The output side (secondary side) of the power supply circuit 42 is connected to the secondary side ground 62, 5V potential portion 63, 12V potential portion 64, and 24V potential portion 65 on the substrate 11, and is connected to the 5V potential portion. The DC power supply voltages of 5V, 12V, and 24V are output between each of the 63, 12V potential portion 64, and the 24V potential portion 65 and the secondary side ground 62, respectively.

The 5V DC power supply voltage generated by the power supply circuit 42 is, more specifically, a voltage that matches 5V or substantially matches 5V within a predetermined range. This also applies to the DC power supply voltage of 12 V and the DC power supply voltage of 24 V.

Each motor drive circuit 43 is connected to the 12V potential portion 64 and the secondary side ground 62 on the substrate 11 so that a DC power supply voltage of 12V is applied. Further, each motor drive circuit 43 is connected to the stepping motor 21 via an energizing line of the harness 12a so as to be able to supply power to the corresponding stepping motor 21, and also receives a control command from the microcomputer 41. It is connected to the microcomputer 41 on the board 11.

Then, each motor drive circuit 43 supplies the electric power generated from the DC power supply voltage of 12 V to the stepping motor 21 in response to the control command given from the microcomputer 41, so that the required operation (control command) of the stepping motor 21 is supplied. It is configured to perform the operation according to.

The power supply (application of voltage) from each motor drive circuit 43 to the corresponding stepping motor 21 is intermittently performed at a predetermined drive frequency (for example, 125 Hz).

The thermal fuse 22 harnesses the 12V potential portion 64 and the forced valve closing circuit 45 so that a DC power supply voltage of 12V can be supplied from the 12V potential portion 64 to the forced valve closing circuit 45 via the thermal fuse 22. It is connected via the power line of 12b. Therefore, the forced valve closing circuit 45 is connected to the 12V potential portion 64 via the thermal fuse 22 and the energizing wires of the harness 12b (the energizing wires connected to both ends of the thermal fuse 22).

Then, the forced valve closing circuit 45 outputs a 12V DC power supply voltage given from the 12V potential portion 64 via the thermal fuse 22 to the respective solenoids (not shown) of the gas main valve 23 and each gas solenoid valve 24. As obtained, they are connected to the respective solenoids of the gas main valve 23 and each gas solenoid valve 24 via the energizing wire of the harness 12b.

Therefore, when the thermal fuse 22 is disconnected, the forced valve closing circuit 45 is not supplied with the DC power supply voltage of 12 V. Therefore, the output of the DC voltage of 12 V from the forced valve closing circuit 45 to the respective solenoids of the gas main valve 23 and each gas solenoid valve 24 is also cut off.

Of the energizing wires of the harness 12b, the energizing wire 12b1 of the 12V power supply is branched from the energizing wire between the thermal fuse 22 and the forced valve closing circuit 45. As shown in FIG. 3, the energizing line 12b1 is used as an energizing line for supplying a DC power supply voltage of 12V to the water amount sensor 26, the hot water amount sensor 27, the hot water beam valve 30, and the refill valve 31.

The forced valve closing circuit 45 further receives a signal output from the solenoid valve drive circuit 44 when the operation of the solenoid valve drive circuit 44 is abnormal, or a control command from the microcomputer 41, so that the solenoid valve drive circuit 44 and the microcomputer 41 receive the control command. Is connected to and on the substrate 11. Then, the forced valve closing circuit 45 responds to the above signal given from the solenoid valve drive circuit 44 or the control command given from the microcomputer 41, and 12V to each solenoid of the gas main valve 23 and each gas solenoid valve 24. It is configured so that the output of the DC power supply voltage of can be cut off.

In this case, the shutoff operation of the output of the 12V DC power supply voltage to the respective solenoids of the gas main valve 23 and each gas electromagnetic valve 24 is, for example, on / off control of the switching element (not shown) included in the forced valve closing circuit 45. Made by.

The solenoid valve drive circuit 44 is a gas main valve so that the solenoids of the gas main valve 23 and each gas electromagnetic valve 24 can be energized in a state where a DC power supply voltage of 12 V is output from the forced closing circuit 45. It is connected to each of the solenoids of the 23 and each gas solenoid valve 24 via the energizing wire of the harness 12b, and is also connected to the secondary side ground 62 on the substrate 11.

Further, the solenoid valve drive circuit 44 is connected to the solenoid valve 41 on the substrate 11 so that a control command can be received from the solenoid valve 41 and a signal indicating the operating state of the solenoid valve drive circuit 44 can be output to the solenoid valve 41. Then, the solenoid valve drive circuit 44 energizes the solenoids of the required solenoid valves of the gas main valve 23 and the gas solenoid valve 24 in a predetermined cycle in response to a control command given from the microcomputer 41 (pulse drive). By energizing by a method), the solenoid valve is controlled to open, and by constantly shutting off the energization of the solenoid of the solenoid valve, the solenoid valve is closed.

In this case, the opening / closing control of the gas main valve 23 and each gas solenoid valve 24 as described above is performed by, for example, on / off control of a plurality of switching elements (not shown) included in the solenoid valve drive circuit 44.

The motor drive circuit 43, the solenoid valve drive circuit 44, and the forced valve closing circuit 45 described above are circuits having known configurations.

Each thermistor 25 of the harness 12c is connected in series between the 5V potential portion 63 and the secondary side ground 62 to the voltage dividing resistor 51 mounted on the substrate 11 corresponding to the thermistor 25. It is connected to the voltage dividing resistor 51 and the secondary side ground 62 via an energizing wire. Then, the midpoint between the thermistor 25 and the voltage dividing resistor 51 is set so that the voltage between both ends of each thermistor 25 is output to the detection circuit 47 as a detection signal indicating the temperature detected by the thermistor 25. It is connected to the detection circuit 47 on the substrate 11.

The water amount sensor 26 and the hot water amount sensor 27 are connected to the energizing line 12b1 branched from the harness 12b so that a DC power supply voltage of 12V is supplied from the 12V potential portion 64 via the thermal fuse 22. At the same time, it is connected to the secondary side ground 62 via the energizing wire of the harness 12c.

The water amount sensor 26 and the hot water amount sensor 27 are configured to output a pulse signal according to the water flow rate (water supply flow rate or hot water flow rate) in a state where a DC power supply voltage of 12 V is supplied. There is. The pulse signal is, for example, a signal in the frequency range of 0 to 400 Hz. Then, the water amount sensor 26 and the hot water amount sensor 27 detect through the energizing line of the harness 12c so that the pulse signal is output to the detection circuit 47 as a detection signal of the water flow rate (water supply flow rate or hot water flow amount). It is connected to the circuit 47.

The detection circuit 47 is configured to convert the detection signal given to each of the thermistor 25, the water amount sensor 26, and the hot water amount sensor 27 into an input signal for the microcomputer 41, and the input signal is converted into the input signal for the microcomputer 41. It is connected to the microcomputer 41 on the board 11 so as to output to.

The floor heating remote controller 28 and the bathroom heating remote controller 29 are respectively connected to the 24V potential portion 65 and the secondary side ground 62 via the energizing line of the harness 12d so that the DC power supply voltage of 24V is applied from the substrate 11 side. At the same time, it is connected to the communication circuit 48 via the energizing line of the harness 12d so that it can communicate with the microcomputer 41 via the communication circuit 48.

Further, the communication circuit 48 is connected to the microcomputer 41 on the substrate 11 so as to be able to send and receive communication data to and from the microcomputer 41, and the communication data given from the floor heating remote controller 28 or the bathroom heating remote controller 29 is transmitted to the microcomputer 41. It is configured so that it can be transmitted to 41, or communication data from the microcomputer 41 to the floor heating remote controller 28 or the bathroom heating remote controller 29 can be transmitted to the corresponding remote controller 28 or 29.

The communication data between each of the floor heating remote controller 28 and the bathroom heating remote controller 29 and the microcomputer 41 is data composed of pulse signals in a predetermined frequency band.

The hot water valve 30 and the refill valve 31 are composed of solenoid valves, and the DC power supply voltage of 12 V is supplied from the 12 V potential portion 64 through the thermal fuse 22 at one end of each solenoid. It is connected to the energizing wire 12b1 branched from the harness 12b, and the other end of each solenoid is connected to each of the hot water valve drive circuit 49 and the refill valve drive circuit 50 via the energizing wire of the harness 12e. There is.

Then, each of the hot water valve drive circuit 49 and the hot water valve drive circuit 50 is in a state where a DC power supply voltage of 12 V is applied to the solenoids of the hot water valve 30 and the hot water valve 31, respectively. It is connected to the secondary side ground 62 on the substrate 11 so that each solenoid of the water replenishment valve 31 can be energized.

Further, each of the hot water valve drive circuit 49 and the refill valve drive circuit 50 is connected to the microcomputer 41 on the substrate 11 so as to receive a control command from the microcomputer 41, and the hot water valve drive circuit 49 is connected to the hot water valve drive circuit 49. By energizing the solenoid of the hot water valve 30 at a predetermined cycle (energizing by a pulse drive method) in response to a control command given from the microcomputer 41, the hot water beam valve 30 is controlled to open and the hot water beam is opened. The hot water valve 30 is configured to be closed by constantly shutting off the energization of the solenoid of the valve 30.

Similarly, the refill valve drive circuit 50 energizes the solenoid of the refill valve 31 at a predetermined cycle (energizes by a pulse drive method) in response to a control command given from the microcomputer 41, thereby causing the refill valve 31 to be energized. It is configured to close the water replenishment valve 31 by controlling the valve opening and constantly shutting off the energization of the solenoid of the water replenishment valve 31.

In this case, the opening / closing control of the hot water valve 30 and the refill valve 31 as described above is, for example, on / off of a plurality of switching elements (not shown) included in each of the hot water valve drive circuit 49 and the refill valve drive circuit 50. Made by control.

In the present embodiment, the drive frequencies of the hot water valve 30 and the water replenishment valve 31 (frequency of energization of each solenoid) when the hot water valve 30 and the water replenishment valve 31 are controlled to open by a pulse drive method. Is based on the drive frequencies of the solenoids of the hot water valve 30 and the water replenishment valve 31 (frequency of energization of each solenoid) when the gas main valve 23 and each gas electromagnetic valve 24 are controlled to open by a pulse drive method. Is also a high frequency. In the present embodiment, the drive frequencies of the hot water valve 30 and the refill valve 31 are, for example, 500 Hz, and the drive frequencies of the gas source valve 23 and each gas solenoid valve 24 are, for example, 250 Hz.

The ground fault detection circuit 46 corresponds to the ground fault current detector in the present invention. In the ground fault detection circuit 46, the 5V potential portion 63 and the 12V potential portion 64 are caused by the occurrence of a ground fault in which the current-carrying wire of any of the harness 12 is electrically conducted to the conductor portion of the housing 2. When a current flowing through the energized wire in which a ground fault has occurred and the housing 2 (hereinafter referred to as a ground fault current) is generated from any of the 24V potential portion 65 and the ground fault current, the magnitude of the ground fault current is increased. It is configured to be able to generate a detected signal (analog signal).

In this embodiment, the ground fault detection circuit 46 is configured as shown in FIG. 4, for example. The ground fault detection circuit 46 includes a ground fault current detection resistor 72 that generates a voltage corresponding to the ground fault current, a pair of voltage dividing resistors 73 and 74 that divide the voltage generated in the resistance element 72, and a ground fault detection. It includes a Zener diode 75 that limits the upper limit of the voltage of the detection signal generated by the circuit 46, two noise filter circuits 71 and 76, and a buffer circuit 77.

One end of the ground fault current detection resistor 72 is connected to a housing ground potential portion 61 (a portion connected to the same potential as the housing 2) of the substrate 11 via a noise filter circuit 71 that removes high-frequency noise components. At the same time, the other end is connected to the secondary side ground 62 of the substrate 11.

Then, a series circuit formed by connecting the voltage dividing resistors 73 and 74 in series is connected in parallel to the ground fault current detection resistor 72. The resistance values of the voltage dividing resistors 73 and 74 are such that the combined resistance value of the entire resistance circuit composed of the voltage dividing resistors 73 and 74 and the ground fault current detection resistor 72 is the ground fault current detection resistor 72. The resistance value is set to be sufficiently larger than the resistance value of the ground fault current detection resistor 72 so that the resistance value is close to the resistance value.

In this case, the voltage generated at the midpoint between the voltage dividing resistors 73 and 74 (the voltage between both ends of the voltage dividing resistors 74) is a voltage corresponding to the magnitude of the current flowing through the ground fault current detection resistor 72. Then, the midpoint between the voltage dividing resistors 73 and 74 is connected to the input side of the buffer circuit 77 via the noise filter circuit 76 that removes high-frequency noise components, and the output side of the buffer circuit 77 is connected to the microcomputer 41. Has been done. As a result, the voltage generated at the midpoint between the voltage dividing resistors 73 and 74, that is, the voltage corresponding to the magnitude of the current flowing through the ground fault detecting resistor 72, is transmitted to the microcomputer via the noise filter circuit 76 and the buffer circuit 77. It will be input to 41.

Further, the midpoint between the voltage dividing resistors 73 and 74 is connected to the 5V potential portion 63 of the substrate 11 via the Zener diode 75. As a result, the upper limit of the voltage generated at the midpoint between the voltage dividing resistors 73 and 74 is limited to 5V.

In the present embodiment, the ground fault detection circuit 46 is configured as described above.

Here, any of the 5V potential portion 63, the 12V potential portion 64, and the 24V potential portion 65 is caused by the occurrence of a ground fault (conduction to the conductor portion of the housing 2) of the current-carrying wire of any of the harness 12. When a ground fault current flows from the potential portion to the housing 2, the ground fault current is transmitted from the housing 2 through the housing ground potential portion 61 and the noise filter circuit 71 to detect the ground fault current 72. Flow to.

For example, as illustrated in FIG. 5, it is assumed that a ground fault of the energizing line occurs between the gas solenoid valve 24 of any of the harnesses 12b and the solenoid valve drive circuit 44. In this case, as shown by the arrow line Y of the one-point chain line in FIG. 5, from the 12V potential portion 64, the solenoid of the gas solenoid valve 24, the energizing line in which the ground fault has occurred, the housing 2, the housing grounding potential portion 61, and noise. A ground fault current flows through the ground fault current detection resistor 72 via the filter circuit 71. The switch element 44a shown in FIG. 5 is a switch element included in the solenoid valve drive circuit 44.

The phenomenon that the ground fault current flows through the ground fault current detection resistor 72 is that when a ground fault occurs in any of the current-carrying wires (including the current-carrying wire 12b1) of the harness 12a or the harness 12b shown in FIG. Or, when a ground fault occurs in any of the current-carrying wires other than the current-carrying wire connected to the secondary ground 62 among the harness 12c or the harness 12d shown in FIG. 3, or the harness 12e shown in FIG. This is a phenomenon that can occur when a ground fault occurs in any of our current-carrying wires.

Then, the voltage corresponding to the magnitude of the ground fault current flowing through the ground fault current detection resistor 72 (hereinafter referred to as the ground fault detection voltage) is input to the microcomputer 41 in this way. The ground fault detection voltage is a voltage signal that is substantially proportional to the magnitude of the ground fault current.

The microcomputer 41 has a function of controlling the operation of the water heater 1 by executing a program stored in a memory (not shown), and is based on a ground fault detection voltage input from the ground fault detection circuit 46. It has a function of detecting the occurrence of a ground fault and further identifying the energizing line in which the ground fault has occurred based on the magnitude of the ground fault detection voltage and its change pattern. Therefore, the microcomputer 41 has a function as a current-carrying wire specifying unit in the present invention.

Further, the microcomputer 41 displays information indicating which current-carrying wire the ground fault has occurred in, such as a kitchen remote controller (not shown) connected to the substrate 11 (not shown). It has a function that can be notified by the display of.

Here, in the present embodiment, the magnitude of the ground fault current flowing through the ground fault detection resistor 72 when a ground fault occurs or the frequency of its change is the type of electronic component to which the energizing line that caused the ground fault is connected. Alternatively, it depends on the operating state of the electronic component, the magnitude of the power supply voltage (5V or 12V or 24V) of the electronic component, and the like.

For example, when a ground fault occurs in any of the energizing wires of the harness 12a related to the stepping motor 21, the ground fault current flowing through the ground fault detecting resistor 72 during the operation of the stepping motor 21 to which the energizing wire is connected. Will fluctuate at the same frequency as the drive frequency (125 Hz) of the stepping motor 21.

Further, for example, when a ground fault of the current-carrying wire between one of the gas solenoid valves 24 and the solenoid valve drive circuit 44 occurs in the harness 12b related to the gas solenoid valve 24, the gas solenoid valve 24 is closed. Then, the ground fault current flowing through the ground fault current detection resistor 72 is a substantially constant direct current. On the other hand, in the valve open state of the gas solenoid valve 24, the ground fault current flowing through the ground fault current detection resistor 72 fluctuates at the same frequency as the drive frequency (250 Hz) of the gas solenoid valve 24.

Further, for example, when a ground fault of the current-carrying wire between one of the gas solenoid valves 24 and the solenoid valve drive circuit 44 occurs in the harness 12b related to the gas solenoid valve 24, the gas solenoid valve 24 is closed. And, in the open state of the gas solenoid valve 24, the energization resistance of the solenoid of the gas solenoid valve 24 is different, so that the magnitude of the ground fault current is also different.

In addition, the magnitude of the ground fault current basically increases as the power supply voltage (5V, 12V, or 24V) of the electronic component corresponding to the energizing line in which the ground fault occurs increases.

In this way, the magnitude or frequency of the ground fault current flowing through the ground fault current detection resistor 72 when a ground fault occurs (and thus the magnitude or frequency of the ground fault detection voltage input to the microcomputer 41) is It depends on the type of electronic component to which the current-carrying wire that caused the ground fault is connected, the operating state of the electronic component, or the magnitude of the power supply voltage (5V or 12V or 24V) of the electronic component. Become.

In the present embodiment, the microcomputer 41 is configured to be able to identify the energizing line in which the ground fault has occurred by utilizing the above items.

In this case, in the present embodiment, in order to be able to identify the current-carrying wire in which the ground fault has occurred, which electronic component the current-carrying wire in which the ground fault has occurred is connected to, or the said The resistance values of the ground fault current detection resistance 72 and the voltage dividing resistors 73 and 74 of the ground fault detection circuit 46 are set so that the magnitude of the ground fault detection voltage changes as clearly as possible according to the operating state of the electronic component. It is set in advance.

As a result, the ground fault detection voltage input from the ground fault detection circuit 46 to the microcomputer 41 is, for example, as shown in FIGS. 6 and 7, when no ground fault has occurred and when a ground fault has occurred. Therefore, the voltage becomes a different magnitude, and the voltage becomes a different magnitude depending on which energizing wire the ground fault has occurred in. Further, the frequency of the ground fault detection voltage matches or substantially matches the drive frequency of the electronic component to which the energizing wire in which the ground fault has occurred is connected.

FIG. 6 shows the magnitude and frequency of the ground fault detection voltage in the standby state in which the water heater 1 is not operated (hot water supply operation, bath operation, and heating operation). As shown in the figure, when the ground fault does not occur normally, the ground fault detection voltage falls within the range of 0.2 V or less as shown in the region R1.

Then, in the standby state, for example, the energizing line of any of the thermistors 25 (specifically, the energizing line between the thermista 25 and the voltage dividing resistor 51) or the energizing line of the gas source valve 23 (specifically, gas). The energizing line between the solenoid of the main valve 23 and the solenoid valve drive circuit 44, or the energizing line of any gas solenoid valve 24 (specifically, between the solenoid of the gas solenoid valve 24 and the solenoid valve drive circuit 44). When a ground fault of the current-carrying wire) occurs, a ground fault detection voltage having a magnitude in the range of 0.2 to 2 V is generated as shown in the region R2. This ground fault detection voltage is a voltage having a substantially constant value (about 0 Hz).

Further, in the standby state, for example, an energizing line to which a DC power supply voltage of 12V is applied (specifically, each energizing line connected to both ends of the thermal fuse 22 or the energizing line 12b1, the gas main valve 23 or each gas. When a ground fault occurs in the current-carrying wire between the solenoid of the electromagnetic valve 24 and the forced valve closing circuit 45, which has almost the same potential as the 12V potential portion 64), 3 to 3 to as shown in region R3. A ground fault detection voltage with a magnitude within the range of 4.5V is generated. This ground fault detection voltage is a voltage having a substantially constant value (about 0 Hz).

Further, in the standby state, for example, a ground fault of an energizing line to which a DC power supply voltage of 24V is applied (specifically, an energizing line between the floor heating remote controller 28 or the bathroom heating remote controller 29 and the 24V potential portion 65) occurs. In this case, as shown in the region R4, a ground fault detection voltage having a magnitude in the range of 4.5 to 5 V is generated. This ground fault detection voltage is a voltage having a substantially constant value (about 0 Hz).

Further, in the standby state, a ground fault of the communication energizing line of the floor heating remote controller 28 or the bathroom heating remote controller 29 (specifically, the energizing line between the floor heating remote controller 28 or the bathroom heating remote controller 29 and the communication circuit 48). When the above occurs, as shown in the region R5, a ground fault detection voltage having a magnitude in the range of 4.5 to 5 V and fluctuating in a certain frequency band (for example, a frequency band of 125 Hz or higher) is generated. ..

Further, FIG. 7 shows the magnitude and frequency of the ground fault detection voltage in a situation where any electronic component such as the stepping motor 21 is operating due to the operation of the water heater 1 (hot water supply operation, bath operation, or heating operation). It represents. As shown in the figure, in the normal state where no ground fault has occurred, the ground fault detection voltage falls within the range of 0.2 V or less as shown in the region R11, as in the case of the standby state.

On the other hand, for example, when the water amount sensor 26 or the hot water amount sensor 27 is activated, the energizing line of the water amount sensor 26 or the hot water amount sensor 27 (specifically, the water amount sensor 26 or the hot water amount sensor 27 and the detection circuit 47 When a ground fault occurs between the current lines), a ground fault detection voltage having a magnitude within the range of 1 to 3 V is generated as shown in the region R12. This ground fault detection voltage is a voltage that fluctuates in a certain frequency band (for example, a frequency band of about 125 to 400 Hz).

Further, for example, when a ground fault occurs in the energizing line of the stepping motor 21 (specifically, the energizing line between the stepping motor 21 and the motor drive circuit 43) when any of the stepping motors 21 is operated. As shown in the region R13, a ground fault detection voltage having a magnitude in the range of 3 to 4.5 V is generated. This ground fault detection voltage is a voltage that fluctuates at a frequency of 125 Hz, which is the drive frequency of the stepping motor 21.

Further, for example, at the time of valve opening control of the gas main valve 23 or any of the gas solenoid valves 24, the energizing line of the gas main valve 23 or the gas solenoid valve 24 (specifically, the gas main valve 23 or the gas solenoid valve 24 When a ground fault occurs in the current-carrying wire between the solenoid and the forced valve closing circuit 45), a ground fault detection voltage having a magnitude in the range of 3 to 4.5 V is generated as shown in the region R14. This ground fault detection voltage is a voltage that fluctuates at a frequency of 250 Hz, which is the drive frequency at the time of valve opening control of each of the gas main valve 23 and each gas solenoid valve 24.

Further, for example, when the hot water valve 30 or the refill valve 31 is controlled to open, the current-carrying line of the hot water valve 30 or the replenishment valve 31 (specifically, the solenoid of the hot water valve 30 or the refill valve 31 and the hot water valve drive). When a ground fault of the circuit 49 or the current-carrying wire between the water replenishment valve drive circuit 50) occurs, a ground fault detection voltage having a magnitude in the range of 3 to 4 V is generated as shown by the region R15. This ground fault detection voltage is a voltage that fluctuates at a frequency of 500 Hz, which is the drive frequency at the time of valve opening control of each of the hot water valve 30 and the refill valve 31.

Next, the processing of the microcomputer 41 regarding the detection of the ground fault will be specifically described with reference to the flowcharts of FIGS. 8 to 11.

The microcomputer 41 executes the processes shown in the flowcharts of FIGS. 8 to 11 in a state where the power is turned on (a state in which the power of the commercial power supply is supplied to the board 11).

In STEP 1, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46.

Then, the microcomputer 41 executes the process of determining whether or not the acquired ground fault detection voltage Vx is larger than 0.2V in STEP2. In the present embodiment, in the processing of the microcomputer 41, the ground fault detection voltage Vx to be compared with a certain threshold value such as 0.2V is the voltage value when the Vx is a substantially constant constant voltage. , When the voltage fluctuates periodically, it is the peak value.

The situation in which the determination result of STEP 2 is negative is a normal state in which no ground fault has occurred, as shown in the region R1 of FIG. 6 or the region R11 of FIG. In this case, the microcomputer 41 repeats the process from STEP 1 assuming that the state is normal in STEP 3.

A situation in which the determination result of STEP 2 is positive is a situation in which a ground fault occurs in which one of the energizing wires conducts with the housing 2. In this case, the microcomputer 41 then determines in STEP 4 whether or not the state of the water heater 1 is the standby state. Then, in the microcomputer 41, when the state of the water heater 1 is the standby state (when the determination result of STEP 4 is affirmative), which is the energized line in which the ground fault has occurred (hereinafter referred to as the ground fault energized line). If the process from STEP 5 is executed to identify whether it is an energized line and it is not in the standby state (because hot water supply operation, bath operation, or heating operation is being performed, the judgment result of STEP 4 is negative. In the case), the process from STEP 24 described later is executed in order to specify which the ground fault energizing line is.

In STEP 5 when the state of the water heater 1 is the standby state, the microcomputer 41 puts the water heater 1 in the operation prohibited state in STEP 6, and further acquires the ground fault detection voltage Vx again in STEP 6.

Then, in STEP 7, the microcomputer 41 has a range in which the ground fault detection voltage Vx is Vx> 4.5V, a range in which 3V <Vx ≦ 4.5V, a range in which 0.2V <Vx ≦ 3V, and Vx ≦ 0. . Determine which range of the 2V range it belongs to.

The range in which Vx> 4.5V is the range to which the regions R4 and R5 shown in FIG. 6 belong. Therefore, it can be considered that a ground fault has occurred in the energizing line of the floor heating remote controller 28 or the bathroom heating remote controller 29 (the energizing line to which the DC power supply voltage of 24V is applied, or the energizing line for communication).

Therefore, in STEP7, when Vx> 4.5V, the microcomputer 41 determines whether or not the frequency of the ground fault detection voltage Vx is 0 Hz (or almost 0 Hz) in STEP8 (in other words, Vx is almost 0 Hz). Whether or not it is a constant voltage signal with a constant value) is determined.

If this determination result is affirmative, in STEP 9, the ground fault energizing line is the energizing line (floor heating) of the floor heating remote controller 28 or the bathroom heating remote controller 29 to which a 24V DC power supply voltage is applied. It is specified as a power line between the remote controller 28 or the bathroom heating remote controller 29 and the 24V potential portion 65 of the board 11, and error information indicating that fact is transmitted via the display unit of the main remote controller such as the kitchen remote controller. Output.

If the determination result of STEP 8 is negative, in STEP 10, the ground fault energizing line is the communication energizing line of the floor heating remote controller 28 or the bathroom heating remote controller 29 (floor heating remote controller 28 or bathroom). It is specified as an energizing line between the heating remote controller 29 and the board 11 communication circuit 48), and error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

In the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is 3V <Vx ≦ 4.5V is the range to which the region R3 shown in FIG. 6 belongs. Therefore, it can be considered that a ground fault has occurred in the energized line to which the DC power supply voltage of 12 V is applied.

Therefore, when 3V <Vx ≦ 4.5V in STEP 7, the microcomputer 41 uses the ground fault energizing line in STEP 11 to apply a DC power supply voltage of 12V to both ends of the temperature fuse 22. An error indicating that it is the connected current-carrying wire or the current-carrying wire 12b1, or the current-carrying wire between the solenoid of the gas main valve 23 or each gas electromagnetic valve 24 and the forced valve closing circuit 45). The information is output via the display unit of the main remote controller such as the kitchen remote controller.

In the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is 0.2V <Vx ≦ 3V is the range to which the region R2 shown in FIG. 6 belongs. Therefore, it can be considered that a ground fault has occurred in the energizing line of any of the thermistors 25, the energizing line of the gas main valve 23, or the energizing line of any of the gas solenoid valves 24.

In this case, the microcomputer 41 executes the process from STEP 12 of FIG. 9 in order to specify the ground fault energizing line in more detail.

In STEP 12, the microcomputer 41 controls the opening of one of the gas main valve 23 and the gas electromagnetic valve 24, for example, the gas main valve 23 via the solenoid valve drive circuit 44. The other solenoid valves (here, all the gas solenoid valves 24 except the gas main valve 23) are held in the closed state.

Then, in the state where the gas source valve 23 is controlled to open in this way, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 12, and the ground fault detection voltage Vx is set to the ground fault detection voltage Vx. STEP 14 determines whether or not the voltage is within the range of 3V <Vx ≦ 4.5V.

The situation in which this determination result is positive is that the ground fault detection voltage Vx in the state where only the gas main valve 23 is controlled to open belongs to the region R14 shown in FIG. 7, so that the gas main valve 23 It can be considered that a ground fault of the energizing line (the energizing line between the solenoid of the gas source valve 23 and the solenoid valve drive circuit 44) has occurred.

Therefore, when the determination result of STEP 14 is affirmative, the microcomputer 41 closes the gas main valve 23 via the solenoid valve drive circuit 44 in STEP 15, and the ground fault energizing line is changed to the gas main valve 23. It is identified as the current-carrying wire of the above, and error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

If the determination result of STEP 14 is negative, the microcomputer 41 then closes the gas source valve 23 via the solenoid valve drive circuit 44 and distinguishes the gas solenoid valve 24 in STEP 16. Let the value of the identification number i be "1".

Then, the microcomputer 41 determines in STEP 17 whether or not the current value of the identification number i is equal to or less than the total number of the gas solenoid valves 24.

When i = 1, the determination result of STEP 17 is positive. Then, when the determination result of STEP 17 is affirmative, the microcomputer 41 controls the opening of the gas solenoid valve 24 of No. i in STEP 18 via the solenoid valve drive circuit 44. The other solenoid valves (here, all the gas solenoid valves 24 and the gas source valves 23 except the gas solenoid valve 24 of No. i) are held in the closed state.

In the state where the gas solenoid valve 24 of No. i is controlled to open in this way, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 19, and the ground fault detection voltage Vx is set to the ground fault detection voltage Vx. STEP 20 is used to determine whether or not the voltage is within the range of 3V <Vx ≦ 4.5V.

The situation in which this determination result is affirmative is that the ground fault detection voltage Vx in the state where only the gas solenoid valve 24 of No. i is controlled to open belongs to the region R14 shown in FIG. It can be considered that a ground fault has occurred in the current-carrying wire of the gas solenoid valve 24 (the current-carrying wire between the solenoid of the gas solenoid valve 24 and the solenoid valve drive circuit 44).

Therefore, when the determination result of STEP 20 is affirmative, the microcomputer 41 closes the gas solenoid valve 24 of No. i via the solenoid valve drive circuit 44 in STEP 22, and the ground fault energizing line is i. It is identified as the energizing line of the gas solenoid valve No. 24, and error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

If the determination result of STEP 20 is negative, the microcomputer 41 closes the gas solenoid valve 24 of No. i via the solenoid valve drive circuit 44 in STEP 21, and sets the value of the identification number i to ". After increasing by 1 ”, the process from STEP 17 is executed again.

The situation in which the determination result of STEP 17 is negative is a situation in which it can be considered that a ground fault in the energizing lines of the gas main valve 23 and the gas solenoid valve 24 has not occurred. Therefore, if the determination result of STEP 17 is negative, it can be considered that a ground fault has occurred in the energizing line of any of the thermistors 25 (the energizing line between the thermistor 25 and the voltage dividing resistor 51).

Therefore, when the determination result of STEP 17 is negative, the microcomputer 41 identifies in STEP 23 that the ground fault energizing line is the energizing line of one of the thermistors 25, and provides error information indicating that fact. Output via the display of the main remote controller such as the kitchen remote controller.

Further, in STEP 7 in the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is Vx ≦ 0.2V is the range to which the region R1 shown in FIG. 6 belongs, that is, a ground fault has occurred. There is no range of Vx under normal conditions. Therefore, in STEP 7, when Vx ≦ 0.2V, the microcomputer 41 restarts the processing from STEP 1 without outputting the error information.

Here, the microcomputer 41 continues the process from STEP 5 after executing any of the processes of STEP 9, 10, 11, 22, 23. In this case, if the cause of the ground fault is eliminated by changing or replacing the wiring path of the energizing line in which the ground fault has occurred, Vx ≦ 0.2V in STEP7. As a result, the processing from STEP 1 is restarted.

When a ground fault occurs in the standby state of the water heater 1, the process of specifying the ground fault energizing line is performed as described above. In this case, the ground fault energizing line can be roughly specified by classifying the ground fault detection voltage Vx into four types of ranges and determining the ground fault detection voltage Vx in STEP7.

Further, when Vx> 4.5V in STEP7, the DC power supply voltage of 24V of the floor heating remote controller 28 or the bathroom heating remote controller 29 is applied by determining the frequency of the ground fault detection voltage Vx in STEP8. The ground fault energizing line can be specified by distinguishing the energizing line from the energizing line for communication.

When 0.2V <Vx ≦ 3V in STEP7, the gas main valve 23 and the gas solenoid valve 24 are sequentially controlled to open, and the ground fault detection voltage Vx at the time of each valve opening control (during operation). Based on the above, for each of the energizing lines of the gas main valve 23 and the gas solenoid valve 24, a process of determining whether or not the energizing line has a ground fault is executed in order. As a result, when 0.2V <Vx ≦ 3V in STEP 7, it is properly specified which of the gas source valve 23, the gas solenoid valve 24, and the thermistor 25 is the ground fault energizing line. be able to.

Next, when the determination result of STEP4 is negative, that is, when Vx> 0.2V in STEP2 and the occurrence of a ground fault is detected, the state of the water heater 1 is the operating state (hot water supply operation). Or, in the case of a bath operation or a heating operation), the microcomputer 41 executes the process from STEP 24 in FIG.

In STEP 24, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46. Then, in STEP 25, the microcomputer 41 determines which range of the range in which the ground fault detection voltage Vx is Vx> 3V, 0.2V <Vx ≦ 3V, and Vx ≦ 0.2V. to decide.

The range in which Vx> 3V is the range to which the regions R13, R14, and R15 shown in FIG. 7 belong. Then, in the present embodiment, when a ground fault occurs in any of the energizing lines of the gas main valve 23 and the gas solenoid valve 24, the ground fault energizing line is specified by the water heater 1 as described above. It is performed in the standby state of.

Therefore, when Vx> 3V in STEP 25, the energizing line of any of the stepping motors 21 (the energizing line between the stepping motor 21 and the motor drive circuit 43), or the hot water valve 30 or the refill valve. A ground fault occurs in the energizing line of 31 (the energizing line between the solenoid of the hot water valve 30 and the hot water valve drive circuit 49, or the energizing line between the solenoid of the refill valve 31 and the refill valve drive circuit 50). It can be considered that it was done.

In this case, the microcomputer 41 executes the process from STEP 26 in order to specify the ground fault energizing line in more detail.

In STEP 26, the microcomputer 41 determines whether or not the frequency of the ground fault detection voltage Vx acquired in STEP 24 matches or substantially matches 125 Hz, which is the drive frequency of the stepping motor 21.

If the determination result of STEP 26 is affirmative, it can be considered that a ground fault in the energizing line of any of the stepping motors 21 has occurred. Then, in this case, the microcomputer 41 first forcibly stops the operation of the water heater 1 in STEP 27, and then identifies which stepping motor 21 the energizing line in which the ground fault has occurred is. The process is executed from STEP 28.

In STEP 28, the microcomputer 41 sets the value of the identification number j for distinguishing the stepping motor 21 to "1".

Next, in STEP 29, the microcomputer 41 feeds the stepping motor 21 via the motor drive circuit 43 corresponding to the stepping motor 21 so as to operate the stepping motor 21 No. j in a predetermined mode.

Then, in the state where the stepping motor 21 of No. j is operated in this way, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 30, and the ground fault detection voltage Vx is set to the ground fault detection voltage Vx. STEP31 determines whether or not the voltage is within the range of 3V <Vx ≦ 4.5V.

The situation in which this determination result is affirmative is that the ground fault detection voltage Vx in the state where only the stepping motor 21 of the j is operated belongs to the region R13 shown in FIG. It can be considered that a ground fault of the energizing line of the motor 21 (the energizing line between the stepping motor 21 and the corresponding motor drive circuit 43) has occurred.

Therefore, when the determination result of STEP 31 is affirmative, the microcomputer 41 stops the operation of the stepping motor 21 of No. j in STEP 33, and the ground fault energizing line is the energizing line of the stepping motor 21 of No. j. The error information indicating that is output is output via the display unit of the main remote controller such as the kitchen remote controller.

If the determination result of STEP 31 is negative, the microcomputer 41 stops the operation of the stepping motor 21 of number j in STEP 32, and increases the value of the identification number j by "1". , The process from STEP 29 is executed again.

If the determination result of STEP 26 is affirmative, it is specified in which stepping motor 21 the energizing line the ground fault has occurred as described above.

On the other hand, if the determination result of STEP 26 is negative, it can be considered that the energizing line in which the ground fault has occurred is the energizing line of either the hot water valve 30 or the refill valve 31. Then, in this case, the microcomputer 41 further executes the process from STEP 34 in order to identify which of the electric wire of the hot water valve 30 and the refill valve 31 has a ground fault.

In STEP 34, the microcomputer 41 forcibly stops the operation of the water heater 1 and opens one of the hot water valve 30 and the refill valve 31, for example, the hot water valve 30 via the hot water valve drive circuit 49. Valve control.

Then, in the state where the hot water valve 30 is controlled to open in this way, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP35, and the ground fault detection voltage Vx is set to the ground fault detection voltage Vx. STEP36 determines whether or not Vx> 0.2V.

The situation in which this determination result is positive is that the ground fault detection voltage Vx in the state where the hot water valve 30 is controlled to open belongs to the region R15 shown in FIG. 7, so that the hot water valve 30 It can be considered that a ground fault of the current-carrying wire (the current-carrying wire between the solenoid of the hot water valve 30 and the hot water valve drive circuit 49) has occurred.

Therefore, when the determination result of STEP 36 is affirmative, the microcomputer 41 closes the hot water valve 30 in STEP 37 and identifies that the ground fault energizing line is the energizing line of the hot water valve 30. , The error information indicating that is output via the display unit of the main remote controller such as the kitchen remote controller.

Further, in the situation where the determination result of STEP 36 is negative, the ground fault detection voltage Vx in the state where the hot water valve 30 is controlled to open is the value at the normal time when no ground fault has occurred, so that the refill valve is used. It can be considered that a ground fault of the energizing line of 31 (the energizing line between the solenoid of the refilling valve 31 and the refilling valve drive circuit 50) has occurred.

Therefore, when the determination result of STEP 36 is negative, the microcomputer 41 closes the hot water valve 30 in STEP 38, and identifies that the ground fault energizing line is the energizing line of the refill valve 31. Error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

As described above, when Vx> 3V in STEP 25, it is specified by the processing of STEP 26 to 38 which of the stepping motor 21, the hot water valve 30, and the refill valve 31 the ground fault has occurred. To.

In STEP 26, for example, it is determined whether the frequency of Vx matches or substantially matches 500 Hz, which is the drive frequency for valve opening control of the hot water valve 30 and the refill valve 31, and this determination result is negative. In addition, the process from STEP 27 may be executed, and if affirmative, the process from STEP 34 may be executed.

Next, in STEP 25, the range in which the ground fault detection voltage Vx is 0.2V <Vx ≦ 3V is the range to which the region R12 shown in FIG. 7 belongs. Therefore, when 0.2V <Vx ≦ 3V in STEP 25, the energizing line of the water amount sensor 26 or the hot water amount sensor 27 (between the water amount sensor 26 or the hot water amount sensor 27 and the detection circuit 47). It can be considered that a ground fault has occurred in the current-carrying wire).

In this case, the microcomputer 41 executes the process from STEP 39 of FIG. 11 in order to specify the ground fault energizing line in more detail. In STEP 39, the microcomputer 41 forcibly stops the operation of the water heater 1 and then starts the hot water filling of the bathtub again. Hot water filling the bathtub is started by controlling the opening of the hot water valve 30.

In this way, the microcomputer 41 is input from the ground fault detection circuit 46 in STEP 40 in the state where the hot water is poured into the bathtub (in other words, the hot water amount sensor 27 can detect the amount of hot water). The ground fault detection voltage Vx is acquired, and it is determined in STEP 41 whether or not the ground fault detection voltage Vx is 0.2V <Vx ≦ 3V.

The situation in which this determination result is positive is that the ground fault detection voltage Vx in a state where the hot water flow rate sensor 27 can detect the hot water flow rate belongs to the region R15 shown in FIG. It can be considered that a ground fault of the energizing wire of the amount sensor 27 (the energizing wire between the hot water amount sensor 27 and the detection circuit 47) has occurred.

Therefore, when the determination result of STEP 41 is affirmative, the microcomputer 41 stops the hot water flow to the bathtub (closes the hot water beam valve 30) in STEP 42, and at the same time, the ground fault energizing line is changed to the hot water beam. It is identified as the energizing line of the amount sensor 27, and error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

If the determination result of STEP 41 is negative, the microcomputer 41 stops the hot water flow to the bathtub (closes the hot water flow valve 30) in STEP 43, and the ground fault energizing line is the water amount sensor. It is identified as the power supply line of 26, and error information indicating that fact is output via the display unit of the main remote controller such as the kitchen remote controller.

Further, in the STEP 25 in the operating state of the water heater 1, the range in which the ground fault detection voltage Vx is Vx ≦ 0.2 V is the range to which the region R11 shown in FIG. 7 belongs, that is, a ground fault has occurred. There is no range of Vx under normal conditions. Therefore, in STEP 25, when Vx ≦ 0.2V, the microcomputer 41 restarts the processing from STEP 1 without outputting the error information.

Here, the microcomputer 41 continues the process from STEP 24 after executing any of the processes of STEP 33, 38, 42, and 43. In this case, if the cause of the ground fault is eliminated by changing or replacing the wiring path of the energizing line in which the ground fault has occurred, Vx ≦ 0.2V in STEP 25. As a result, the processing from STEP 1 is restarted.

When a ground fault occurs in the operating state of the water heater 1, the process of specifying the ground fault energizing line is performed as described above. In this case, the ground fault energizing line can be roughly specified by classifying the ground fault detection voltage Vx into three types of ranges in STEP 25 and determining the voltage.

When Vx> 3V in STEP 25, the frequency of the ground fault detection voltage Vx is determined in STEP 26 to separate the energizing line of the stepping motor 21 from the energizing line of the hot water valve 30 and the refill valve 31. Separately, the ground fault energizing line can be specified.

Further, when the determination result of STEP 26 is affirmative, a plurality of stepping motors 21 are operated in order, and based on the ground fault detection voltage Vx at the time of each operation, each energizing line of the stepping motor 21 is used. , The process of determining whether or not the electric wire has a ground fault is executed in order. Thereby, it is possible to properly identify which stepping motor 21 the ground fault energizing line is.

Further, when the determination result of STEP 26 is negative, the magnitude of the ground fault detection voltage Vx is set to STEP 36 in a state where one of the hot water valve 30 and the refill valve 31, for example, the hot water valve 30 is opened and controlled. It is possible to properly identify which of the hot water valve 30 and the refill valve 31 the ground fault energizing line is.

Further, when 0.2V <Vx ≦ 3V in STEP 25, the magnitude of the ground fault detection voltage Vx is determined in STEP 41 in a state where the hot water in the bathtub is performed and the hot water amount sensor 27 is operated. Therefore, it is possible to properly identify which of the water amount sensor 26 and the hot water amount sensor 27 is the current-carrying wire for the ground fault.

As described above, according to the present embodiment, when a ground fault occurs, the ground fault energizing line can be properly specified. Then, by notifying the specified ground fault energizing line, the worker who performs the ground fault resolving work can recognize which energizing line the ground fault occurred in, so that the ground fault resolving work (ground fault occurs). It is possible to easily replace the energized wire, modify the arrangement path of the energized wire, etc.) in a short time.

The present invention is not limited to the embodiments described above. Some other embodiments will be described below. For example, when the frequency of the ground fault detection voltage Vx acquired in STEP 6 belongs to the communication frequency band of the floor heating remote controller 28 and the bathroom heating remote controller 29, the ground fault energizing line is connected regardless of the magnitude of Vx. , The floor heating remote controller 28 or the bathroom heating remote controller 29 may be specified as an energizing line for communication.

Further, for example, when the ground fault detection voltage Vx acquired in STEP 13 is a substantially constant voltage (when the frequency is about 0 Hz), any of the ground fault energizing lines is used regardless of the magnitude of Vx. It may be specified that it is an energizing line of the thermistor 25 of.

Further, for example, when the ground fault detection voltage Vx acquired in STEP 24 matches or almost matches 125 Hz, which is the drive frequency of the stepping motor 21, the ground fault energizing line is eventually used regardless of the magnitude of Vx. It may be specified as the energizing line of the stepping motor 21.

Further, in STEP 34, instead of controlling the opening of the hot water valve 30, the refill valve 31 is controlled to open, and when the ground fault detection voltage Vx acquired in this state is Vx> 0.2V, the ground fault The energizing line may be specified as the energizing line of the refill valve 31.

Further, in the above embodiment, the frequency of Vx is used as an index showing the change pattern of the ground fault detection voltage Vx. However, the ground fault energizing line may be specified based on the change pattern of the ground fault detection voltage Vx when the operating state of a certain electronic component is changed from a certain predetermined state to another state.

Further, the ground fault detection circuit 46 may be a circuit having a configuration different from that of the above embodiment as long as it can detect the ground fault current.

Further, in the above-described embodiment, the bath water heater 1 having a hot water heating function is exemplified as the device in the present invention, but the device to which the present invention is applied may be, for example, a water heater not provided with the hot water heating function. Good. Furthermore, the present invention is not limited to water heaters, and can be applied to various devices such as air conditioning systems.

1 ... Bath water heater with hot water heating function (equipment), 2 ... Housing, 12 (12a-12e) ... Harness (energization line), 41 ... Microcomputer (energization line identification part), 46 ... Ground fault detection circuit (ground) Intercurrent detector).

Claims (1)

This is a phenomenon in which, in a device including a housing in which energizing wires for energizing a plurality of electronic components are arranged inside, a conductor portion of the housing and an energizing wire for energizing any of the electronic components are conducted. A ground fault detection device having a function of identifying which electronic component is the energizing wire for energizing when a ground fault occurs.
When the ground fault occurs, it has a resistance to flow a ground fault current, which is a current flowing through the current-carrying wire and the housing in which the ground fault has occurred, and the resistance is generated according to the ground fault current. A ground fault current detector that detects the ground fault current by the voltage to be generated and generates a ground fault detection voltage that is an output voltage corresponding to the ground fault current.
Comprising a ground fault detection voltage of該地fault current detector, based on at least the fluctuating frequency of the fluctuation frequency of the ground fault detection voltage, and a current supply line specifying unit that specifies the current line the ground fault has occurred And
When the energizing line specifying unit identifies the energizing line in which the ground fault has occurred based on the fluctuating frequency, the determination result of which of a plurality of preset frequencies the fluctuating frequency is. A ground fault detecting device characterized in that it is configured to identify the energizing line in which the ground fault has occurred based on the above .