JP7814746B2 - water heater - Google Patents

Description

This disclosure relates to a water heater equipped with a controller including an electrical board.

The water heater includes a combustion chamber that houses a burner and a heat exchanger, a controller that controls the burner, and other components housed in a housing. The housing includes a box body and a front cover that closes the front of the box body. As disclosed in Patent Document 1, for example, the controller is configured by housing an electrical circuit board in a box-shaped storage case that is placed vertically within the box body. The storage case has an opening on the front so that the electrical circuit board can be accessed with the front cover removed.
The storage case is provided with a drip-proof cover to prevent a decrease in drip-proof performance due to the opening. The drip-proof cover consists of a main cover that extends vertically, covering the opening from the front, and a sub-cover that bends rearward from the top end of the main cover. A plurality of cover mounting parts with horizontal holes are provided on the left and right sides of the top surface of the storage case. The rear edge of the sub-cover is provided with a plurality of mounting sites on the left and right sides, each of which fits with the cover mounting parts and has a protrusion that can be inserted into the horizontal holes. When each mounting site is attached to its corresponding cover mounting site, the sub-cover is inclined downwards toward the front. Therefore, water droplets that fall on the sub-cover are drained to the front side of the main cover.

Patent No. 6451479

In the circuit board storage structure of Patent Document 1, when water flowing on the sub-cover adheres to the cover mounting portion, the water will flow down the cover mounting portion due to capillary action onto the top surface of the storage case. If the top surface of the storage case has a mold draft angle required for resin molding that slopes downward toward the front, water will flow down the front of the storage case. Therefore, if the water droplets that flow down enter the interior of the storage case through the opening, there is a risk of shorting out the electrical circuit board.

The present disclosure therefore aims to provide a water heater that can improve the drip-proofing properties of the controller.

In order to achieve the above object, the present disclosure provides a combustion chamber having a burner and a heat exchanger, and a controller for controlling the burner, which are housed in a housing;
A water heater in which the controller includes an electrical board, a box-shaped storage case that houses the electrical board and is placed vertically in a housing, and has one side open except for the top and bottom, and a cover whose upper part is attached to the top of the storage case and closes the opening,
The upper surface of the storage case is provided with a locking portion that can lock onto a locking portion provided on the upper part of the cover, and a drainage portion that is located below the locking portion and slopes downward toward a surface other than the opening ,
The locking portion is a gate-shaped protrusion that protrudes upward from the top surface of the storage case,
The locked portion is a notch through which the locking portion can pass, and is characterized in that holes are provided adjacent to both ends of the notch, into which both ends of the locking portion that has passed through the notch fit .

According to the present disclosure, even if water droplets that fall onto the cover and adhere to the latching portion flow into the gap between the storage case and the cover due to capillary action, the drainage portion causes the water droplets to flow to the side opposite the opening of the storage case and fall, preventing them from flowing into the interior of the storage case through the opening. This improves the water resistance of the controller.
In particular, the locking portion is a gate-shaped protrusion that protrudes upward from the top surface of the storage case, and the locked portion is a notch through which the locking portion can pass, with holes on both ends into which the locking portions that pass through the notch fit. This makes it easy to attach and detach the locked portion to the storage case. Also, because the notch closes when the cover is attached, water droplets are less likely to seep in between the storage case and the cover.

FIG. FIG. 2 is a front view of the water heater with the front cover removed. 2 is a cross-sectional view taken along line AA in FIG. 1. This is an oblique view of the inside of the housing as seen from the left rear, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. This is an oblique view of the inside of the housing as seen from the right rear, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. This is an oblique view of the inside of the housing as seen from the front right, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. FIG. 3 is an enlarged cross-sectional view taken along line BB in FIG. 2. FIG. 2 is an exploded perspective view of the controller from the front. FIG. 2 is an exploded perspective view of the controller from the rear. FIG. 10 is an enlarged perspective view of a locking portion of the upper plate of the cover. FIG. 3 is an enlarged cross-sectional view of the CC line portion of FIG. 2.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
(Explanation of the overall configuration of the water heater)
Fig. 1 is a front view showing an example of a water heater, Fig. 2 is a front view with a front cover removed, and Fig. 3 is a cross-sectional view taken along line AA in Fig. 1.
The water heater 1 has a vertically long box-shaped housing 2. The housing 2 comprises a box body 3 and a front cover 4. The box body 3 is open at the front and has a deep bottom at the front and rear. The front cover 4 is screwed to the box body 3 from the front to close the front. A cylindrical exhaust port 37, which is provided on the front side of the upper casing 19 (described later), penetrates the top of the front cover 4.
The box body 3 includes a top plate 5, a bottom plate 6, left and right side plates 7A, 7B, and a back plate 8. The bottom plate 6 is provided with a water inlet 9 for connection to an external water pipe, a hot water outlet 10 for connection to an external hot water tap, a bath return port 11 and a bath supply port 12 for connection to an external bathtub. The center of the bottom plate 6 is provided with a gas inlet 13 for connection to an external gas pipe, and a drain port 14 for connection to a neutralizer 55 (described below). Mounting plates 15, 15 are provided above and below the back plate 8 for installation on a wall or the like.

A combustion chamber 16 is provided at the rear side of the box body 3. The combustion chamber 16 includes a lower casing 17, a middle casing 18, and an upper casing 19 that are connected in the vertical direction.
The lower casing 17 houses a plurality of burner units 20. Each burner unit 20 is composed of a plurality of flat burners 21 extending in the front-rear direction and arranged side by side in the left-right direction. The number of burners 21 varies from one burner unit 20 to another.
As shown in Figure 4, a combustion fan 22 is connected to the underside of the lower casing 17. The combustion fan 22 is rotated around an axis extending in the front-to-rear direction by a fan motor 23 provided on the rear side. The combustion fan 22 supplies combustion air to the burner unit 20.
A gas distribution unit 25 is provided on the front side of the lower casing 17. The gas distribution unit 25 is equipped with a plurality of solenoid valves, and can switch the burner unit 20 to be combusted by opening and closing each solenoid valve. A gas pipe 26 equipped with a main valve and a proportional valve is connected to the upstream end of the burner unit 20. The gas pipe 26 is connected to the gas inlet 13.

The inner casing 18 houses a hot water supply primary heat exchanger 27 and a bath heat exchanger 28. The hot water supply primary heat exchanger 27 has multiple fins 29, 29... arranged at a predetermined interval in the left-right direction, and hot water supply side heat transfer pipes 30 that serpentinely penetrate each fin 29 in two rows, one above the other. The bath heat exchanger 28 has each fin 29 and a bath side heat transfer pipe 31 that serpentinely penetrates each fin 29 between the upper and lower rows of hot water supply side heat transfer pipes 30. In other words, the water heater 1 is a one-tank, two-channel type in which the hot water supply primary heat exchanger 27 and the bath heat exchanger 28, which have different paths, are installed side by side within a single inner casing 18 and heated by a common burner unit 20.

The upper casing 19 houses a hot water secondary heat exchanger 32. The hot water secondary heat exchanger 32 houses a plurality of serpentine heat absorption pipes 33. As shown in Figure 4, both ends of each heat absorption pipe 33 are connected to an inlet header 34 and an outlet header 35 provided on the left side surface of the upper casing 19, respectively, so that the inlet ends and the outlet ends are in communication with each other.
The upper casing 19 is connected to the middle casing 18 at their rear ends. The upper casing 19 is supported in a position inclined downwards toward the front, and is provided at its front with a drain pan 36 that is flat at the front and rear. An exhaust port 37 is connected to the front of the drain pan 36 and faces forward.
A water supply pipe 40 is connected to the water inlet 9. The water supply pipe 40 is routed upward on the left side of the combustion chamber 16 and connected to the inlet header 34 of the upper casing 19.
A relay pipe 41 is connected to the outlet header 35. As shown in Fig. 5 , the relay pipe 41 runs from the left side of the combustion chamber 16, passes behind the intermediate casing 18, and wraps around to the right side of the intermediate casing 18. The relay pipe 41 is then routed forward on the right side of the intermediate casing 18 and connected to the upstream end of the lower section of the hot water supply side heat transfer pipe 30 of the hot water supply primary heat exchanger 27.

A hot water outlet pipe 42 is connected to the downstream end of the upper section of the hot water supply side heat transfer pipe 30. As shown in Fig. 6 , the hot water outlet pipe 42 wraps around from the right side surface of the inner casing 18 to the front of the inner casing 18, crosses the front of the inner casing 18, and moves to the left side of the inner casing 18. Then, as shown in Fig. 4 , the hot water outlet pipe 42 bends downward at the front left of the inner casing 18, is routed downward in a straight line, and is then connected to the hot water outlet 10. A straight section 43 of the hot water outlet pipe 42 is connected to the water supply pipe 40 via a bypass pipe 44.
A bath return pipe 45 is connected to the bath return port 11. As shown in Figures 4 to 6, the bath return pipe 45 is routed upward along the right side of the combustion chamber 16 via a pump 46. The bath return pipe 45 then crosses the front of the inner casing 18, wraps around to the left side of the inner casing 18, and is connected to the upstream end of the bath-side heat transfer pipe 31 of the bath heat exchanger 28. The bath return pipe 45 is connected to the hot water outlet pipe 42 via a drop pipe 47.
A bath supply pipe 48 is connected to the bath supply port 12. The bath supply pipe 48 is routed upward along the right side of the combustion chamber 16, and then connected to the downstream end of the bath-side heat transfer pipe 31 on the right side of the middle casing 18.

A resin sheet 50 is wound around the combustion chamber 16. As shown in Figures 1, 2 and 7, the resin sheet 50 is a strip-shaped body that straddles the lower casing 17 and the middle casing 18 and is wound around the combustion chamber 16. The resin sheet 50 is wound around the outside of each pipe along the inner surfaces of the left and right side plates 7A, 7B and the back plate 8, so that it is not in contact with the combustion chamber 16.
A continuous conductive pattern 51, which meanders back and forth in the width direction and extends longitudinally, is printed on the resin sheet 50 over the entire length in the longitudinal direction. Both ends of the conductive pattern 51 are electrically connected to an electrical circuit board 66 (described later) to form an overheat prevention device. When abnormal overheating of the lower casing 17 or the middle casing 18 causes cracks, holes, or the like, resulting in the emission of combustion exhaust gas, the resin sheet 50 melts and the conductive pattern 51 breaks, causing the resistance value to suddenly increase or become infinite. The electrical circuit board 66 detects this change in resistance value and stops the supply of fuel gas, thereby extinguishing the burner unit 20.

A neutralizer 55 is disposed in front of the combustion chamber 16. The neutralizer 55 is a rectangular box when viewed from the front, and is filled with a neutralizing agent (not shown). Drain discharge pipes 56, 56 are connected to the front bottom surface of the upper casing 19 and the drain receiver 36. A drain pipe 57 is connected to the drain outlet 14 and is connected to the bottom surface of the neutralizer 55.
3, the upper part of the neutralizer 55 is fixed via a mounting bracket 59 that is L-shaped in side view to a bracket 58 fixed downward from the middle casing 18 and the upper casing 19. The lower part of the neutralizer 55 is fixed to a fixing bar 60 that is fixed to the lower casing 17 on the front side of the gas distribution unit 25 and extends in the left-right direction.
A controller 65 is disposed below the neutralizer 55. The controller 65 includes an electrical board 66, a storage case 67, and a cover 68. The controller 65 will be described in detail later.

(Explanation of water heater operation)
In the water heater 1, normal hot water supply is performed as follows.
When the hot water tap on the external pipe connected to the hot water outlet 10 is opened to allow water to flow into the appliance and the flow of water is detected by a hot water supply volume sensor provided on the water supply pipe 40, the controller 65 rotates the combustion fan 22 for a predetermined time to discharge (pre-purge) the combustion exhaust gas accumulated in the combustion chamber 16. Thereafter, the controller 65 opens the main valve of the gas pipe 26 and the solenoid valve of the gas distribution unit 25, opens the proportional valve to a predetermined opening, supplies gas to the burner unit 20, and activates the igniter to ignite the burner unit 20.
As a result, the water supplied from the water supply pipe 40 exchanges heat with the combustion exhaust gas from the burner unit 20 and recovers latent heat as it flows through the heat absorption pipe 33 of the hot water secondary heat exchanger 32. The drain generated at this time is collected in the neutralizer 55 via the drain discharge pipe 56, neutralized with a neutralizing agent, and then discharged from the drain pipe 57 to the outside of the appliance.
The hot water that has passed through the hot water secondary heat exchanger 32 flows to the hot water primary heat exchanger 32 via the relay pipe 41, and as it flows through the hot water side heat transfer pipe 30, it exchanges heat with the combustion exhaust gas from the burner unit 20 to recover sensible heat. The hot water heated in this way passes through the hot water outlet pipe 42 and external piping and is discharged from the hot water tap.

The electrical board 66 of the controller 65 monitors the outlet temperature, which is the temperature of the hot water discharged immediately after the hot water primary heat exchanger 27, using an outlet temperature thermistor installed in the hot water outlet pipe 42, and drives the distribution valve installed in the bypass pipe 44 to control the flow rate (bypass rate) to the bypass pipe 44 so that the outlet temperature is maintained within a temperature range that can prevent the generation of drainage or overheating in the hot water primary heat exchanger 27.
In addition, the electrical board 66 monitors the outlet hot water temperature using an outlet hot water temperature thermistor installed in the outlet hot water pipe 42, and controls the opening and closing of each solenoid valve in the gas distribution unit 25 and adjusts the opening of the proportional valve so that the outlet hot water temperature becomes the set temperature specified by the external hot water remote control or bath remote control, and also continuously changes the amount of air by controlling the rotation speed of the combustion fan 22.
When the hot water tap is closed, the electrical board 66 confirms that the signal from the hot water volume sensor has stopped, closes the main valve and the solenoid valve of the gas distribution unit 25 to extinguish the burner unit 20, and rotates the combustion fan 22 for a predetermined time (post-purge).

On the other hand, when the automatic switch on the hot water supply remote control or bath remote control is pressed, the electrical circuit board 66 opens the drop water solenoid valve provided in the drop pipe 47 to pass water through the hot water primary heat exchanger 27 and the hot water secondary heat exchanger 32, igniting the burner unit 20. Hot water from the hot water outlet pipe 42 is supplied to the external bathtub through the drop pipe 47 and the bath return pipe 45. When the water volume detected by the bath water volume sensor provided in the drop pipe 47 reaches the set water volume, the electrical circuit board 66 closes the drop water solenoid valve to stop the water flow and extinguish the burner unit 20.
Next, the electrical board 66 activates the pump 46 to circulate hot water between the bath heat exchanger 28 and the bathtub. At this time, the electrical board 66 monitors the temperature of the circulating hot water using thermistors installed in the bath return pipe 45 and bath supply pipe 48, and if it detects a drop from the set temperature, it ignites the burner unit 20 and supplies combustion air using the combustion fan 22, just as when supplying hot water. Therefore, the bath circulating water circulating between the bath heat exchanger 28 and the bathtub is heated to the set temperature by heat exchange with the combustion exhaust gas of the burner unit 20 as it flows through the bath-side heat transfer pipe 31. When the set temperature is reached, the electrical board 66 stops the combustion of the burner unit 20 and stops the pump 46.

(Controller description)
As shown in Figures 8 and 9, the storage case 67 for the controller 65 is made of resin and has an open front and a horizontally elongated rectangular shape when viewed from the front. The inner bottom surface on the rear side serves as a holder for the electrical board 66. A pair of left and right mounting pieces 69, 69 are formed on the top surface of the storage case 67 facing upward. Each mounting piece 69 has a small hole 70 formed therethrough.
A pair of left and right cover mounting portions 71, 71 are provided on the left and right outer sides of the mounting pieces 69, 69. The cover mounting portions 71, 71 are protrusions that extend in the front-to-rear direction with a flat upper surface. However, a locking portion 72 that protrudes upward from the rear end of each cover mounting portion 71 is formed as a gate-shaped protrusion in a front-to-rear view. In addition, a drain groove 73 is formed on the upper surface of each cover mounting portion 71, sloping downward from the center in the front-to-rear direction toward the rear. The drain groove 73 is formed below the locking portion 72 to the rear end of the cover mounting portion 71.

A pair of left and right support portions 74, 74 are formed on the underside of the storage case 67. Each support portion 74 is block-shaped and extends downward from the underside of the storage case 67. A conical locking protrusion 75 that tapers downward is formed on the underside of each support portion 74. A pair of through holes 76, 76 corresponding to the locking protrusions 75, 75 are formed in the bottom plate 6 of the box body 3.
A downward-facing protrusion 77 (FIG. 2) is formed on the underside of the storage case 67 to the left of the left support portion 74. A plurality of hooks 78, 78, ... are formed on the underside of the storage case 67 for engaging cables connected to the electrical board 66.
The electrical board 66 is a printed circuit board having a horizontally elongated rectangular shape when viewed from the front, and various control components such as a microcomputer and memory are mounted on the front surface thereof. The electrical board 66 is fitted into the inner bottom surface of the storage case 67 from the front and positioned therein.

The cover 68 is a resin sheet-like member that is inverted L-shaped in side view and has a top plate 80 and a front plate 81. The top plate 80 is strip-shaped and slightly larger in both the front and rear and left and right directions than the top surface of the storage case 67. A pair of left and right notches 82, 82 into which the left and right mounting pieces 69, 69 fit are formed at the rear end of the top plate 80.
A pair of left and right notches 83 are formed on the left and right outer sides of the cutouts 82. The notches 83 extend in the left-right direction corresponding to the locking portions 72 of the cover mounting portions 71. Square holes 84 are formed on both left and right ends of each notch 83. The square holes 84 are sized to allow both ends of the locking portions 72 to pass through.
The front plate 81 is connected downward from the front end of the upper plate 80 and has a horizontally long rectangular shape in a front view that covers the front surface of the storage case 67. A bending piece 85 that can be bent backward is formed at the lower left corner of the front plate 81. A locking hole 86 is formed in the bending piece 85. The locking hole 86 corresponds to the protrusion 77 provided on the underside of the storage case 67.
Rearward folded portions 87, 87 are formed in the up-down direction on the left and right side edges of the front panel 81. The folded portions 87, 87 are provided in positions that cover the left and right side surfaces of the storage case 67 from the outside.

In the controller 65 configured as described above, the storage case 67 is screwed to the fixed bar 60 by a pair of left and right mounting brackets 59, 59. The mounting bracket 59 has the same shape as the bracket that secures the neutralizer 55 to the bracket 58, and includes an upper plate 90, a middle plate 91, and a lower plate 92. The upper plate 90 is a strip-like plate extending vertically and has a through-hole 93 formed therein. The middle plate 91 is a strip-like plate extending forward from the lower end of the upper plate 90. Reinforcing folds are formed on the left and right sides of the upper plate 90 and the middle plate 91. The lower plate 92 is a plate-like plate extending downward from the front end of the middle plate 91 and has a screw hole 94 formed therein.
Each mounting bracket 59 is attached to the mounting piece 69 by positioning the lower plate portion 92 on the back side of the mounting piece 69 and then threading a screw 95 that has been passed through the small hole 70 of the mounting piece 69 from the front into the screw hole 94.
The storage case 67, with the mounting brackets 59, 59 attached and containing the electrical board 66, is positioned by inserting the locking protrusions 75, 75 of the left and right support portions 74, 74 from above into the through holes 76, 76 of the bottom plate 6. In this state, the upper plate portions 90, 90 of the mounting brackets 59, 59 are positioned on the front surface of the fixed bar 60, and screws 96, 96 that have been passed through the through holes 93, 93 from the front, are screwed into screw holes 97, 97 provided in the fixed bar 60, thereby fixing the case to the fixed bar 60.

The top plate 80 of the cover 68 is then placed over the top of the storage case 67 from above the front of the storage case 67. At this time, the left and right notches 83 of the top plate 80 are aligned with the locking portions 72 of the left and right cover mounting portions 71 of the storage case 67, respectively, and the locking portions 72 are inserted through the notches 83 from below. Then, as shown in FIG. 10 , both ends of the locking portions 72 fit into the rectangular holes 84 at both ends of the notch 83, closing the notch 83 and locking the top plate 80 horizontally to the locking portions 72. In this state, the front plate 81 covers the front surface of the storage case 67 from the front. When the protrusions 77 of the storage case 67 are inserted and locked into the locking holes 86 of the bent pieces 85, the front plate 81 is positioned so as to close the front surface of the storage case 67.
Therefore, even if water droplets generated by condensation or the like inside the housing 2 fall onto the upper plate 80 of the cover 68, they will flow directly to the front or rear of the upper plate 80 and fall downward along the front surface of the front plate 81 or the rear surface of the storage case 67. Furthermore, even if water droplets that come into contact with the locking portion 72 protruding from the upper plate 80 penetrate between the upper plate 80 and the cover mounting portion 71 through the notch 83 due to capillary action, they will flow backward through the drain groove 73 provided on the upper surface of the cover mounting portion 71, as shown by the dotted line in Figure 11, and fall downward along the rear surface of the storage case 67. Therefore, water droplets are effectively prevented from penetrating from the front surface of the storage case 67 toward the electrical board 66.

(Effects of the invention relating to the controller)
The water heater 1 of the above-described form accommodates a combustion chamber 16 having a burner 21, hot water primary and secondary heat exchangers 27, 32, and a bath heat exchanger 28 within a housing 2, and a controller 65 for controlling the burner 21. The controller 65 includes an electrical board 66, a box-shaped storage case 67 that houses the electrical board 66 and is placed vertically within the housing 2, and has an open front, and a cover 68 whose upper part is attached to the top surface of the storage case 67 and closes the opening of the storage case 67.
A locking portion 72 is provided on the upper surface of the storage case 67, which can lock onto a notch 83 (an example of a locking portion) provided on the top of the cover 68, and a drain groove 73 (an example of a draining portion) is provided below the locking portion 72 and slopes downward toward a surface other than the opening.
With this configuration, even if water droplets that fall onto the upper plate 80 of the cover 68 and adhere to the locking portion 72 flow between the cover mounting portion 71 and the upper plate 80 due to capillary action, the water droplets will flow to the rear side of the storage case 67 by the drain groove 73 and fall from the rear surface, preventing them from flowing into the storage case 67 through the opening on the front surface. This improves the drip-proof properties of the controller 65.

The locking portion 72 is a gate-shaped protrusion that protrudes upward from the top surface of the storage case 67, and the locked portion is a notch 83 through which the locking portion 72 can pass, and square holes 84 (an example of a hole) are provided at both ends of the notch 83, into which both ends of the locking portion 72 that pass through the notch 83 fit.
Therefore, the cover 68 can be easily attached to and detached from the storage case 67. Furthermore, since the notch 83 is closed when the cover 68 is attached, water droplets are less likely to enter between the upper surface of the cover attachment portion 71 and the upper plate 80.

(Explanation of modified examples)
The drainage section is not limited to a structure inclined from the center in the front-to-rear direction of the upper surface of the cover attachment section, as in the drain groove of the above-mentioned embodiment. It may be inclined along the entire upper surface of the cover attachment section. Instead of providing a protruding cover attachment section on the upper surface of the storage case, the locking section and drainage groove may be provided on the flat upper surface.
The drainage portion is not limited to the drainage groove of the above-described form. For example, the bottom surface of the drainage portion may be a curved surface instead of a flat surface.
The locking portion does not have to be gate-shaped, but may be semicircular, etc. The cross-sectional shape of the locking portion may be round, etc., instead of square. Therefore, both ends of the cutout in the cover are not limited to square holes, and can be changed appropriately to match the cross-sectional shape of the locking portion.
The locked portion is not limited to the notch as described above, but may be a slit that opens to the thickness of the locking portion.
The number of locking portions and locked portions is not limited to two, and may be increased or decreased as appropriate as long as the cover can be fixed.
The engagement structure between the bent pieces of the cover and the projections of the storage case may be provided on both the left and right sides, or may be omitted.
The top, bottom, left and right sides of the storage case may or may not have openings or notches.

In the above embodiment, the controller is placed vertically in the left-right direction and the front of the storage case is open, but the orientation of the controller inside the housing is not limited to the above embodiment and may be placed vertically in the front-to-back direction, for example. Therefore, when the opening of the storage case is oriented horizontally, the drainage section is formed with an inclination in the left-to-right direction.
The controller may be vertically long instead of horizontally long.
The mounting of the storage case within the housing is not limited to the structure described above. For example, the number of mounting brackets may be increased or decreased at the top of the storage case, or the mounting brackets may be omitted and the mounting pieces of the storage case may be directly fixed to the fixed bar. At the bottom of the storage case, the support may be eliminated and only a locking protrusion may protrude from the bottom surface of the storage case. The bottom of the storage case may also be screwed to the housing without using a locking protrusion.

In the above embodiment, the primary and secondary heat exchangers are provided only on the hot water supply side, but a secondary heat exchanger may also be provided on the bath side. A heating heat exchanger may also be provided instead of the bath heat exchanger.
In the above embodiment, the hot water supply primary heat exchanger and the bath heat exchanger are installed in a single casing to form a single-tank, two-channel water heater, but the present disclosure is not limited to single-tank, two-channel water heaters. For example, a two-tank, two-channel water heater may be used, in which a hot water supply combustion chamber with a hot water supply heat exchanger and a bath (or heating, etc.) combustion chamber with a bath (or heating, etc.) heat exchanger are separately installed, and the bath (or heating, etc.) circuit is formed separately from the hot water supply circuit.
However, the present disclosure can also be applied to a water heater that does not have a heat exchanger for a bath or a heater, but only has a heat exchanger for hot water supply.The present disclosure can also be applied to a water heater that is only used for heating or bath use.

1. Water heater, 2. Housing, 3. Box body, 4. Front cover, 16. Combustion chamber, 17. Lower casing, 18. Middle casing, 19. Upper casing, 20. Burner unit, 21. Burner, 22. Combustion fan, 26. Gas piping, 27. Water heater primary heat exchanger, 28. Bath heat exchanger, 32. Water heater secondary heat exchanger, 40. Water supply pipe, 41. Middle Extension pipe, 42... Outlet pipe, 45... Bath return pipe, 48... Bath supply pipe, 50... Resin sheet, 55... Neutralizer, 59... Mounting bracket, 65... Controller, 66... Electrical board, 67... Storage case, 68... Cover, 69... Mounting piece, 71... Cover mounting part, 72... Locking part, 73... Drain groove, 80... Top plate, 81... Front plate, 83... Notch, 84... Square hole.

Claims (1)

A combustion chamber having a burner and a heat exchanger, and a controller for controlling the burner are housed in the housing;
The controller is a water heater including an electrical board, a box-shaped storage case that houses the electrical board and is placed vertically in the housing, and has one side open except for the top and bottom sides, and a cover whose upper part is attached to the top surface of the storage case and closes the opening,
a locking portion that can lock onto a locking portion provided on an upper portion of the cover is provided on the upper surface of the storage case, and a drainage portion that is located below the locking portion and slopes downward toward a surface other than the opening is provided ;
the locking portion is a gate-shaped protrusion that protrudes upward from the top surface of the storage case,
The water heater is characterized in that the engaging portion is a notch through which the engaging portion can pass, and holes are provided at both ends of the notch into which both ends of the engaging portion that pass through the notch fit .