JPH11304247A - Gas water heater - Google Patents

Abstract

(57) [Problem] To provide a gas water heater of the present invention, which enhances the positional accuracy of a switch mounted in a narrow place and facilitates the attachment and detachment of the switch. SOLUTION: An ignition switch 7 for detecting an ignition / extinguishing operation in conjunction with a push-type operation button 17, a first switch 5, and a second switch for detecting a position of a spindle 37 which advances by an operating force of a hydraulic pressure responsive device 1. 6 is provided,
These switches are integrally fixed to the mounting plate 2 to form a switch unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas heater having a plurality of switches.

[0002]

2. Description of the Related Art Conventionally, a gas water heater is provided with a switch interlocking with a push-type operation button for performing ignition / extinguishing and a switch interlocking with a water pressure responsive device for detecting a position of a spindle. By these switch operations, combustion control such as ignition discharge and flame detection is started.

As shown in FIG. 11, a switch 5a for detecting the position of the spindle 37 is provided on the outer periphery of a receiving portion 37a of the spindle 37 linked to the hydraulic pressure responsive device, and when the spindle 37 moves on the axis, the position of the switch 5a is determined. Is set so as to be turned ON / OFF by the receiving portion 37a in accordance with the above.

A switch 5a for detecting the position is provided.
In some cases, a gas water heater equipped with a valve opening device that pushes and opens a magnet-type safety valve by water pressure is provided by the present applicant in Japanese Utility Model Laid-Open No. 4-1789.
Issue. In this gas water heater, a water pressure responsive device that operates by a differential pressure caused by water flow is provided.
As shown in FIG. 9, a valve opening device 34 is provided at the tip of a spindle 37 for transmitting the operation of the hydraulic pressure responsive device. The valve opening device 34 is slidably provided on the spindle 37 so as to face the magnet type safety valve 33. The valve opening device 34 engages with the spindle 37 until the magnet type safety valve 33 is opened and sucked, and moves integrally. . Further, after the magnet type safety valve 33 is fully opened (FIG. 6) by utilizing the forward force of the spindle 37, the engagement with the spindle 37 is released, and the magnetic safety valve 33 is lifted up to a position where it can be closed. Slides backward (FIG. 7). Further, when the spindle 37 advances further, the automatic water supply gas valve 4 is opened (FIG. 8).

In this gas water heater, a magnet type safety valve 33 and an automatic water supply gas valve 4 which are opened / closed by movement of a spindle 37 are provided, so that the opening / closing position of the magnet type safety valve 33 is detected by the advance / retreat position of the spindle 37. And a second switch for detecting the open / close position of the automatic water supply gas valve 4 (not shown). These two position detection switches are provided to perform appropriate ignition control according to the valve opening timing of each valve. For example, the first switch starts the energization for holding the valve open before the magnetic safety valve 33 releases the engagement with the spindle 37, so that the explosion does not occur even if the automatic water supply gas valve 4 is closed improperly. In order to start discharge at the valve opening position of the magnetic safety valve 33, the valve opening position of the magnetic safety valve 33 is detected based on the advance / retreat position of the spindle 37. Also,
The second switch switches the attracting current to the magnet type safety valve 33 to the holding current, and starts and stops the timer for determining the timing to stop the ignition discharge, and starts and stops flame detection. Detecting the opening position of the automatic water supply gas valve 4

[0006]

However, in such a gas water heater, there is a problem that it is difficult to provide individual switches in narrow portions of the body. In particular, in order to perform appropriate ignition control, it is necessary to accurately detect the opening / closing timing of each valve, but there has been a problem that it is difficult to finely adjust the position of the switch in a narrow portion of the body. Therefore, the gas water heater of the present invention solves the above-described problems, and improves the positional accuracy of the switch mounted in a narrow place,
An object of the present invention is to facilitate attachment and detachment of a switch.

[0007]

According to a first aspect of the present invention, there is provided a gas water heater provided in a water supply path from a water faucet to a heat exchanger, for supplying water to the heat exchanger. A hydraulic pressure difference is generated between the primary chamber and the secondary chamber partitioned by the diaphragm to generate an operating force on the diaphragm, a spindle advancing by the operating force of the hydraulic pressure responding apparatus, and a gas flow. A plurality of on-off valves which are provided in series on the path and open the gas flow path by advancing the spindle, a plurality of position detection switches for respectively detecting the open / close state of the on-off valve based on the position of the spindle, and the position detection switch. According to the detection result, in a gas water heater provided with a controller that performs combustion control, the plurality of position detection switches are fixed to a common mounting component to form a switch unit,
The gist is that the above-mentioned attachment parts are attached to the body.

According to a second aspect of the present invention, there is provided a gas water heater comprising: a magnetic safety valve provided in a gas flow path; A gas water heater for opening a valve, a valve opening device for pushing and opening a magnet type safety valve at a tip portion of the spindle, and a push member for pushing and pushing an automatic water supply gas valve at an intermediate position of the spindle, respectively. When the spindle advances in the valve opening direction of the magnetic safety valve due to the passage of water through the gas water heater, an engagement maintaining mechanism for maintaining an engagement state between the spindle and the valve opening device, and a magnetic safety valve driven by advancement of the spindle. After the opening of the valve is completed, the advancing force is used to release the engagement between the spindle and the valve-opening device so that the magnetic safety valve can be closed. After the engagement between the spindle and the valve opening device is released after the completion of the opening of the safety valve, a valve opening order securing mechanism for pushing and opening the water supply automatic gas valve by a pushing member provided on the spindle, and the gas water heater A reset mechanism for re-engaging the spindle and the valve-opening device during the retraction of the spindle due to the stoppage of water supply, wherein the re-engagement of the magnet-type safety valve before the valve is opened and the reset mechanism is performed by the advance / retreat position of the spindle. , A second position detection switch for detecting a position immediately before opening and a position after closing of the automatic water supply gas valve, the first position detection switch and the second position detection switch Is fixed to a common mounting component to form a switch unit, and the mounting component is mounted on a body.

According to a third aspect of the present invention, there is provided a gas water heater comprising: a push-type operation button for performing ignition / extinguishing; An operation switch for detecting a push operation of the operation button is provided, the operation switch is fixed to the attachment component to form a switch unit, and the attachment component is attached to a body.

In the gas water heater according to the first aspect of the present invention having the above-described structure, a plurality of position detection switches are fixed to a mounting part to form a switch unit, and the switch unit is formed in the switch unit before being incorporated into the body. The mutual positional relationship of the switches is set, and the entire switch unit is attached to the body.
Therefore, even if there are a plurality of position detection switches and the mounting location is narrow, the accuracy of the mounting positions of the switches can be improved. In addition, the position detection switch can be easily attached and detached.

Further, the present invention has the above-mentioned structure.
The gas water heater described above comprises a first position detection switch and a second position detection switch.
The position detection switch is fixed to the mounting component to form a switch unit, and the mutual positional relationship of the switches is set in the switch unit before being incorporated into the body, and the switch unit is mounted together with the body. Therefore, even if the attachment position of the first position detection switch and the second position detection switch is a narrow body, the accuracy of the attachment position can be improved. Moreover, the first position detection switch and the second position detection switch can be easily attached and detached.

According to a third aspect of the present invention, there is provided a gas water heater according to the first or second aspect, wherein the operation switch for detecting the push operation of the operation button is a switch. It is integrated into the unit. Therefore, even if the operation switch and the plurality of position detection switches are provided and the mounting portion is a narrow body, the accuracy of the mounting position can be improved. In addition, the position detection switch can be easily attached and detached.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the structure and operation of the present invention described above, a preferred embodiment of a gas water heater of the present invention will be described below with reference to the schematic diagram of FIG. In the water supply path from the water inlet, a faucet 19 that opens and closes the flow path by manual operation of the operation button 17 is provided,
Downstream thereof, a hydraulic pressure responsive device 1 is provided. The hydraulic pressure responsive device 1 is provided with a diaphragm 15 which can be moved back and forth, and a primary chamber 13 and a secondary chamber 12 are formed by partitioning the diaphragm 15. A water governor 16 is provided coaxially with the diaphragm 15 at the entrance to the primary chamber 13 of the hydraulic pressure responsive device 1 to keep the flow rate constant even when the supply water pressure fluctuates. It continues from the primary room 13 (downward in the figure)
A hot water temperature controller 18 is provided in the flow path. Hot water temperature controller 1
At 8, the flow path is branched into a heating path 28 that passes through the venturi 22 to the heat exchanger 23 and then to the mixing section 21, and a bypass path 20 that directly leads to the mixing section 21. Then, the branched flow paths merge at the mixing section 21 to reach a tap. The venturi 22 provided in the heating path 28 has a narrowed flow path and a horizontal hole 22a provided in a direction perpendicular to the flow path. And this horizontal hole 22a
A conduction path 24 is provided from the hydraulic pressure responsive device 1 to the secondary chamber 12 of the hydraulic pressure responsive device 1.

On the other hand, the gas flow path from the gas inlet to the burner 27 is opened by the hydraulic pressure responsive device 1 and is opened and held by the thermoelectromotive force of a thermocouple (not shown). An automatic water supply gas valve 4 that is opened and closed by 1 and an instrument plug 9 that opens and closes a gas supply path in conjunction with manual operation of an operation button 17 are provided. Also,
A water-side shaft 14 for transmitting the moving force of the hydraulic pressure responsive device 1 and a spindle 37 inserted in the gas flow path on the same axis are provided, and are urged by a return spring 32 in the downstream direction (right direction in the figure). . Then, when the moving force overcomes the force of the return spring 32, the spindle 37 is advanced leftward in the figure, and the magnetic safety valve 33, valve opening device 34, and automatic water supply gas valve 4 described later are operated.

As shown in FIG. 5, the magnet type safety valve 33 is provided in a valve chamber 35 on the upstream side of the gas flow path.
A valve body 43 urged in a closing direction by a spring 45 is provided at one end of the valve shaft 36 so as to be able to contact and separate from a seat portion 38 of the main body. At the other end of the valve shaft 36, a suction piece 46 is provided to face the suction surface 47 of the electromagnet.

Downstream of the magnet type safety valve 33, a valve opening device 34 is disposed on the same axis facing the magnet type safety valve 33, and is coaxially inserted into the tip of a spindle 37 for transmitting the movement of the hydraulic pressure responsive device 1. You. Valve opening device 34
Is engaged with the spindle 37 until the magnetic safety valve 33 is opened and suction is performed, and moves integrally. After the magnet type safety valve 33 is fully opened, the engagement with the spindle 37 is performed by the forward movement of the spindle 37. After being opened, the magnetic safety valve 33 slides on the spindle 37 to the position where the valve can be closed, and retreats. When the flow of water is stopped, the spindle 37 is returned to the initial stop position by the hydraulic pressure responsive device 1, and the valve opening device 34 and the spindle 37 are configured to be engaged and returned.

Downstream of the valve opening device 34, a spindle 37 is provided.
Is provided with a water supply automatic gas valve 4 slidably inserted in
Urged by a valve spring 39 to close in the downstream direction,
The second valve chamber 41 is formed in a section between the valve body and the second valve chamber 41 by coming into contact with and separating from the seat portion 40 of the main body. In addition, spindle 3
7 is provided with a push member 42 for opening the automatic water supply water gas valve 4. After the opening of the magnetic safety valve 33 is completed and the engagement between the spindle 37 and the valve opening device 34 is released, the automatic water supply gas valve 4 is pushed by the pushing member 42 of the spindle 37 and opened.

The burner 27 includes an electrode (not shown) for igniting gas by discharge, a thermocouple (not shown) for generating a thermoelectromotive force by combustion heat, and a frame guard (not shown) for detecting a combustion flame. Is provided. A controller 29 is provided for detecting the operation of a switch to be described later, discharging the electrodes, detecting the combustion flame by the frame guard, and energizing the magnet type safety valve 33 to hold the valve open.

As shown in FIG. 1, operation buttons 17 include
An operating shaft 62 that alternately advances and retreats during ignition and fire extinguishing operations, and a push-push mechanism 62a that determines the position of the operating shaft 62
Are provided. This push-push mechanism 62a
The operating shaft 62 is locked at a predetermined position (combustion position) by a pressing operation (ignition operation), and the locking is released by a second pressing operation to return to the start position (stop position) (fire extinguishing operation). . Further, a gas lever 63 abutting on the operating shaft 62 to open and close the instrument plug 9 and a water lever 64 to open and close the faucet 19 in conjunction with the gas lever 63 are provided. Further, a leaf spring 65 is provided on the back surface of the gas lever 63, and an operation switch 7 which is turned on / off by the leaf spring 65 at the time of an ignition / extinguishing operation is provided.

The first switch 5 and the second switch 6, which are two sets of switches for detecting the movement position of the spindle 37 and detecting four positions from the first detection position to the fourth detection position, are provided. It is provided near the spindle 37 so as to be stacked back and forth. The spindle 37 has a water side shaft 1
A projection 37b for operating two sets of switches is provided for each switch on the outer periphery of the receiving portion 37a with which the tip of the contact 4 contacts. Therefore, when the spindle 37 is displaced on the axis, the ON / OFF timing differs for each switch, and the ON / OFF is set at each appropriate position.

As shown in FIGS. 2 and 3, these switches are screwed to an L-shaped mounting plate 2 in advance. On the mounting plate 2, an operation portion is fixed upward so that the operation switch 7 is operated by the leaf spring 65 of the gas lever 63, and the first switch 5 and the second switch 6 are superimposed on the lower side, and the receiving portion of the spindle 37 is received. The actuation part is fixed downward so as to be actuated by the part 37a.
Therefore, a switch unit is formed by the mounting plate 2,
By fixing the mounting plate 2 to the body with the fixing screw 3, each switch is installed at a predetermined position. When the switch is screwed to the mounting plate 2, a jig for regulating the position of the switch is provided to prevent the switch from shifting up, down, left and right due to a gap between the screw and the screw hole. Set.

Next, each operation will be described with reference to FIG. 10 and FIGS. When an ignition operation is performed by the operation button 17, the operation switch 7 is turned on by the movement of the operation button 17, the apparatus enters a standby state, and the instrument plug 9 and the water tap 19 are mechanically opened. Then, when the faucet 19 is opened, water flow is started,
Water flows into the primary chamber 13 of the hydraulic pressure responsive device 1. Primary room 1
When the water from 3 passes through the venturi 22, the pressure in the secondary chamber 12 of the hydraulic pressure responsive device 1 decreases in accordance with the decrease in the water pressure in the lateral hole 22a due to the venturi effect. For this reason,
A differential pressure is generated between the primary chamber 13 and the secondary chamber 12 of the hydraulic pressure responsive device 1 to generate a moving force on the diaphragm 15 that can be moved back and forth in the left direction in the drawing. This force is transmitted to the water side shaft 14 of the hydraulic pressure response device 1, and the spindle 37 is returned to the return spring 32.
It overcomes the force and moves together with the water side shaft 14 to the left in the drawing (hereinafter referred to as “forward”).

The valve opening device 34 starts pushing the valve shaft 36 of the magnetic safety valve 33 from the stop position (state A (FIG. 5)) by the advance of the spindle 37, and starts opening the valve body 43. Further, the spindle 37 is provided with the magnetic safety valve 3.
3 is pressed to the attraction surface 47 of the electromagnet (B
(FIG. 6). At this time, before the attraction piece 46 comes into contact with the attraction surface 47 of the electromagnet, the first switch 5 is turned on, dry battery power is supplied from the controller 29 to the magnet type safety valve 33, and the open state of the magnet type safety valve 33 is changed. Will be kept.

Further, when the spindle 37 advances, the engagement between the valve-opening device 34 and the spindle 37 is released by the force, and the valve-opening device 34 retreats while sliding on the spindle 37 to the right in the drawing, The push to the safety valve 33 is released (state C (FIG. 7)). The release of the pushing force is caused by the fact that the engagement portion between the ball 51 and the concave portion 52 formed in the spindle 37 is released. Further, when the spindle 37 moves forward, it reaches the state D (FIG. 8), and the water supply automatic gas valve 4 is pushed by the pushing member 42 integrated with the spindle 37.
Is pushed to open the valve, and the fuel gas starts flowing to the burner 27.

When the fire extinguishing operation is performed by the operation button 17, the operation button 17 returns to the front, the operation switch 7 is turned off, the appliance plug 9 and the water faucet 19 interlocked with the operation button 17 are closed, and the gas supply path is opened. And the water supply path are closed. When the faucet 19 is closed, the pressure difference between the primary chamber 13 and the secondary chamber 12 of the diaphragm 15 disappears, and the spindle 37 retreats to the stop position (to the right in the drawing) by the force of the return spring 32. Then, the push member 42 integrated with the spindle 37 closes the automatic water supply gas valve 4, and the valve opening device 34 and the spindle 37 are re-engaged (state E (FIG. 9)).

Next, the operation timing and operation of the first switch 5 and the second switch 6 will be described with reference to the operation chart of FIG. The two switches 5, 6 are actuated by respective projections 37b provided on the spindle 37,
Four positions from the first detection position to the fourth detection position are detected. Then, the first switch 5 is turned on / off to detect the first detection position / fourth detection position, and the second switch 6
Are turned ON / OFF to detect the second detection position / third detection position. The first detection position and the second detection position are detected during the movement of the spindle 37 in the valve opening direction by the ignition operation, and the third detection position and the fourth detection position are determined by the fire-extinguishing operation when the spindle 37 is initially stopped. Is detected on the way back to.

The first detection position is detected by the ON operation of the first switch 5, and is set to a position immediately before the start of opening the magnetic safety valve 33. When the first switch 5 is turned on,
The controller 29 energizes the magnet-type safety valve 33 and starts ignition discharge from the igniter 53.
The energization of the magnet type safety valve 33 is started because:
This is because, before the suction piece 46 is pressed against the suction surface 47, an electromagnetic force is generated on the suction surface 47 by the power of the dry battery. In addition, the automatic water supply gas valve is started to prevent explosion ignition even if the automatic water supply gas valve 4 is damaged or bites dust in the seat portion and the valve is closed. The detection is performed by detecting the position immediately before the opening of the magnetic safety valve 33 before the opening of the valve 4. still,
When a predetermined time has elapsed from the opening of the magnetic safety valve 33 to the opening of the automatic water supply gas valve 4, the controller 29 determines that the state is particularly abnormal and determines that the magnet safety valve 3 is open.
The power supply to 3 is stopped and the valve is closed to shut off the gas flow path. Further, the flame detection is started by operating the frame guard 50 in accordance with a sequence described later by the ON operation of the first switch 5, but until the adsorption current to the magnet type safety valve 33 is switched to the holding current, the flame is detected. The setting is such that the magnet type safety valve 33 is not closed even if no detection is made.

The second detection position is detected by the ON operation of the second switch 6, and is set to a position immediately after the start of opening of the automatic water supply gas valve 4 after the pressing of the magnetic safety valve 33 is released. When the second switch 6 is detected as ON, the controller 2
Reference numeral 9 switches the attracting current to the magnet-type safety valve 33 to the holding current and starts counting by a timer that determines the timing for stopping the ignition discharge. Switching the attraction current to the holding current utilizes the electromagnet characteristic of the magnet-type safety valve 33 that once released, does not separate even at a lower current, and switches to a low-level holding current sufficient to hold the magnet-type safety valve 33 open. . (Hereinafter, the high-level current before switching is referred to as an adsorption current, and the current after switching to a low level is referred to as a holding current.) The igniter starts when gas starts to flow (opening of the automatic water supply gas valve 4). The stop timer of 53 is operated, and after sufficient discharge for ignition, the igniter 53 is stopped to ensure reliable ignition. Further, by switching the adsorption current to the holding current, flame detection by the frame guard 50 is effectively started. If the flame cannot be detected by the frame guard 50, the controller 29 stops energizing the magnetic safety valve 33 and closes the magnetic safety valve 33.

Next, the third detection position and the fourth detection position will be described. Since the third detection position is detected by the OFF operation of the second switch 6, the third detection position is set to a position immediately before the automatic water supply water gas valve 4 is closed. Further, the fourth detection position is detected by the OFF operation of the first switch 5, and is set to a stop position side near the reset position of the valve opening device 34.

Here, the reset will be described.
The valve opening device 34 pushes and opens the magnet type safety valve 33, and releases (presses release) the pressing force when pushing and opening the valve to the suction position. Therefore, in order to recover the pressing ability in preparation for the next ignition operation, the spindle 37 has
And the valve opening device 34, that is, the reset needs to be performed. Therefore, the reset position is performed at a position close to the stop position where the spindle 37 is further returned after the water supply automatic gas valve 4 is closed.

When the faucet 19 is closed by the fire extinguishing operation, the spindle 37 retreats in the stop direction (to the right in the drawing) by the action of the hydraulic pressure responsive device 1, and at the position immediately before the closing of the water supply automatic gas valve 4 is completed. When the second switch 6 is turned off, the power supply to the magnet type safety valve 33 is stopped.
7 returns to near the stop position, the valve opening device 34 is reset, and further returns, the first switch 5 is turned off, the flame detection by the frame guard 50 is stopped, and the stop position is reached.

In view of the above, a plurality of switches for controlling ignition / extinguishing are provided.
The switch unit is formed by being screwed to the mounting plate 2. Therefore, even a plurality of switches can be easily attached to a narrow place. Further, when the switches are screwed to the mounting plate 2, the relative positions of the switches can be appropriately set in advance by using a jig. Therefore, the difficulty of finely adjusting the relative positions of the plurality of switches when assembling to the body is eliminated. Furthermore, even if it is a micro switch fixed with screws smaller than the screws normally used for water heaters,
The type of screw for fixing the mounting plate 2 is shared with other screws, and the direction in which the screws are tightened is set to a fixed direction, thereby enabling automatic assembling into a body by a machine.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the spirit of the present invention. It is. For example, the number of switches forming a switch unit is not limited to three.

The switches are not limited to mechanical switches, but may be replaced by various switches such as optical switches and magnetic switches.

[0035]

As described above in detail, according to the gas water heater according to the first, second and third aspects of the present invention, the position of the switch is small even if the mounting position of the switch is narrow. Accuracy can be increased. As a result, there is an excellent effect that the combustion control by the switch can be accurately performed. Further, the switch can be easily attached and detached, and the assembling property is improved.

[Brief description of the drawings]

FIG. 1 is a diagram in which a switch unit according to an embodiment of the present invention is incorporated.

FIG. 2 is a diagram illustrating a switch unit according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a switch unit according to an embodiment of the present invention.

FIG. 4 is a diagram showing the operation of a switch.

FIG. 5 is a schematic view showing the operation of the valve opening device (stopped state).

FIG. 6 is a schematic view showing the operation of the valve opening device (push-off state).

FIG. 7 is a schematic view showing the operation of the valve opening device (disengaged state).

FIG. 8 is a schematic view showing the operation of the valve opening device (combustion state).

FIG. 9 is a schematic view showing an operation of the valve opening device (an engagement return state).

FIG. 10 is a schematic configuration diagram of a gas water heater.

FIG. 11 is a mounting diagram of a position detection switch of a conventional gas water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic response apparatus 2 Mounting parts 4 Automatic water supply gas valve 5 First switch 6 Second switch 7 Operation switch 12 Secondary chamber 13 Primary chamber 17 Operation button 33 Magnet type safety valve 34 Valve opening device 37 Spindle

Claims (3)

[Claims] 1. A water pressure difference is generated between a primary chamber and a secondary chamber, which is provided in the middle of a water supply passage from a faucet to a heat exchanger, and is separated by a diaphragm due to the flow of water to the heat exchanger. A water pressure response device that generates an operation force on the diaphragm, a spindle that advances by the operation force of the water pressure response device, a plurality of on-off valves that are provided in series with the gas flow path, and that open the gas flow path by advancement of the spindle; In a gas water heater provided with a plurality of position detection switches for respectively detecting the open / closed state of the on-off valve based on the position of the spindle, and a controller for performing combustion control based on a detection result by the position detection switch, A gas water heater, wherein a detection switch is fixed to a common mounting part to form a switch unit, and the mounting part is mounted on a body. 2. A gas water heater for opening a magnet type safety valve and an automatic water supply gas valve provided in a gas flow path by a spindle which moves forward and backward in accordance with a water flow pressure. A valve opening device that opens and closes the magnetic safety valve, and a push member that pushes and opens the automatic water supply gas valve at an intermediate position of the spindle are provided, and the spindle is opened in the direction of opening the magnetic safety valve of the spindle by passing water through the gas water heater. An engagement maintaining mechanism for maintaining an engaged state between the spindle and the valve-opening device during forward movement; and, after completion of the opening of the magnetic safety valve by the advancement of the spindle, the spindle and the valve-opening device using the forward-moving force. And a disengagement mechanism that releases the engagement of the magnetic safety valve to enable the magnetic safety valve to be closed, and disengages the spindle and the valve opening device after the magnetic safety valve is completely opened. After that, a valve-opening order securing mechanism for pushing and opening the water supply automatic gas valve by a pushing member provided on the spindle, and the spindle and the valve-opening device are again engaged during the retreat of the spindle due to the stoppage of water supply of the gas water heater. A first position detection switch for detecting before the valve opening of the magnetic safety valve and the re-engagement of the reset mechanism based on the advance / retreat position of the spindle; and opening of the water supply automatic gas valve. A second position detection switch that detects immediately before and after the valve is closed based on the advancing / retracting position of the spindle; and fixing the first position detection switch and the second position detection switch to a common mounting component to form a switch unit. A gas water heater characterized in that mounting parts are attached to a body. 3. A push-type operation button for performing ignition / extinguishing, and an operation switch for detecting a push operation of the operation button, wherein the operation switch is fixed to the mounting component to form a switch unit, and 3. The gas water heater according to claim 1, wherein the component is mounted on a body.