JP2024075392A - Water heater - Google Patents

Abstract

To enhance the splash-proof performance of an accommodation case of a controller.SOLUTION: A controller 65 of a water heater 1 includes an electric baseboard 66, a box-shaped accommodation case 67 which accommodates the electric baseboard 66, and is vertically placed in a housing 2, and whose upper face, a lower face and a back face are blocked faces, and whose front face is an opening face 67a, and a cover 68 attached to the upper face of the accommodation case 67, and blocking the opening face 67a of the accommodation case 67. A ventilation port 67b is formed at the upper face of the accommodation case 67, and an upper-side lock part 72a to which the cover 68 can be locked is arranged at the back face side rather than the ventilation port 67b. The cover 68 has an upper plate 80 having a notch 83 and an angular hole 84 to which the upper-side lock part 72a can be locked, and a front plate 81 arranged at the upper plate 80 integrally therewith, and blocking the opening face 67a, and in a state that the upper-side lock part 72a is locked into the notch 83 and the angular hole 84, the upper plate 80 takes an inclination posture which is lowered as progressing toward the back face side from the opening face side 67a.SELECTED DRAWING: Figure 8

Description

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

The water heater accommodates a combustion chamber that houses a burner and a heat exchanger, and a controller that controls the burner, etc., 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 accommodating an electrical circuit board in a box-shaped storage case that is placed vertically within the box body. The storage case has an opening formed in 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-proofness due to the opening. The drip-proof cover is composed of a main cover that covers the opening from the front and extends in the vertical direction, and a sub-cover that is bent backward from the upper end of the main cover. A plurality of cover attachment parts with horizontal holes are provided in the left-right direction on the upper surface of the storage case. A plurality of attachment parts are provided in the left-right direction on the rear end edge of the sub-cover, into which the cover attachment parts are fitted and which have protrusions that can be inserted into the horizontal holes. The sub-cover is inclined forward and downward when each attachment part is attached to each cover attachment part. Therefore, water droplets that fall on the sub-cover are discharged 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 travels around the cover mounting portion by capillary action to the underside of the sub-cover and then flows down to the top of the storage case. If the top of the storage case is formed with a downward slope in the front due to the draft angle of the mold required for resin molding, water flows down to the front of the storage case. Therefore, if the water droplets that flow down enter the inside of the storage case through the opening on the top surface, there is a risk of shorting out the electrical circuit board.

Therefore, the present disclosure aims to provide a water heater that can improve the drip-proofing 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 accommodated in a housing;
A hot water heater comprising a controller including an electrical board, a box-shaped storage case that houses the electrical board and is vertically placed in a housing, with an upper surface, a lower surface, and a surface connecting the upper surface and the lower surface being closed surfaces, and a surface opposite to the closed surfaces being an open surface, and a cover that is attached to the upper surface of the storage case and closes the open surface,
A ventilation hole is formed on the top surface of the storage case, and an upper locking portion on which the cover can be locked is provided on the one surface side of the ventilation hole,
The cover has an upper plate having an engaging portion to which the upper engaging portion can engage, and a vertical plate that is formed integrally with the upper plate and closes the opening surface, and is characterized in that when the upper engaging portion is engaged with the engaging portion, the upper plate is in an inclined position that becomes lower as it moves from the opening surface side toward the one surface side.
Another aspect of the present disclosure is characterized in that, in the above configuration, a support protrusion is provided on the top surface of the storage case closer to the opening surface than the upper engaging portion, which abuts against the underside of the opening surface side of the upper plate that engages the upper engaging portion with the engaged portion, thereby supporting the opening surface side of the upper plate at a position higher than that side.
Another aspect of the present disclosure is characterized in that, in the above configuration, a lower locking portion is provided on the underside of the storage case, while a bent portion is formed on the vertical plate of the cover by bending it toward the underside of the storage case, and the bent portion is provided with a second lockable portion with which the lower locking portion can be locked.

According to the present disclosure, even if rainwater or other water droplets fall on the controller, they are guided to the one side of the storage case by the upper plate of the cover that slopes downward toward the one side connecting the upper and lower sides. In addition, since the locked portion is provided near the one side, even if water droplets flowing on the upper plate flow from the locked portion to the lower side of the upper plate due to capillary action, they will flow directly to the one side of the storage case and fall. This prevents rainwater from entering the inside of the storage case through the opening or ventilation hole, and improves the drip-proofing of the controller.
According to another aspect of the present disclosure, in addition to the above effects, a support protrusion is provided on the top surface of the storage case closer to the opening surface than the upper engaging portion, which abuts against the underside of the opening surface side of the upper plate where the upper engaging portion is engaged with the engaged portion, supporting the opening surface side of the upper plate at a position higher than that side, thereby ensuring that the inclined posture of the upper plate can be maintained.
According to another aspect of the present disclosure, in addition to the above effects, a lower locking portion is provided on the underside of the storage case, while a bent portion is formed on the vertical plate of the cover by bending it toward the underside of the storage case, and the bent portion is provided with a second lockable portion with which the lower locking portion can be locked, thereby preventing the lower part of the vertical plate from shifting out of position away from the opening surface, and ensuring that the opening surface is kept closed by the vertical plate.

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 viewed from the rear left, 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 viewed 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 viewed 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. 3 is an enlarged cross-sectional view of line BB in FIG. 2. FIG. 2 is an exploded oblique view of the controller from the front. FIG. 2 is an exploded perspective view of the controller from the rear. FIG. 4 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, an embodiment 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 showing a state where a front cover is 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 includes a box body 3 and a front cover 4. The box body 3 is open at the front and has a deep bottom from front to back. The front cover 4 is screwed to the box body 3 from the front to close the front. A cylindrical exhaust port 37 provided on the front side of an upper casing 19 (described later) penetrates the upper part of the front cover 4.
The box body 3 comprises 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 connecting to an external water pipe, a hot water outlet 10 for connecting to an external hot water tap, and a bath return port 11 and a bath supply port 12 for connecting to an external bathtub. A gas inlet 13 for connecting to an external gas pipe and a drain port 14 for connecting to a neutralizer 55, which will be described later, are provided in the center of the bottom plate 6. Mounting plates 15, 15 are provided above and below the back plate 8 for installation on a wall surface or the like.

A combustion chamber 16 is provided at the rear side within the box body 3. The combustion chamber 16 includes a lower casing 17, a middle casing 18, and an upper casing 19 that are vertically connected to each other.
The lower casing 17 houses a plurality of burner units 20. Each burner unit 20 is formed by arranging a plurality of flat burners 21 extending in the front-rear direction side by side in the left-right direction. The number of burners 21 differs for each burner unit 20.
As shown in Fig. 4, a combustion fan 22 is connected to the lower surface of the lower casing 17. The combustion fan 22 is rotated around an axis extending in the front-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 includes a plurality of solenoid valves, and is capable of switching the burner unit 20 to be combusted by opening and closing each solenoid valve. A gas pipe 26 including 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 the hot water primary heat exchanger 27 and the bath heat exchanger 28. The hot water primary heat exchanger 27 has a number of fins 29, 29... arranged at a predetermined interval in the left-right direction, and a hot water side heat transfer tube 30 that penetrates each fin 29 in a serpentine manner in two levels, one above the other. The bath heat exchanger 28 has each fin 29 and a bath side heat transfer tube 31 that penetrates each fin 29 in a serpentine manner between the upper and lower hot water side heat transfer tubes 30. In other words, the water heater 1 is a one-can, two-channel type in which the hot water primary heat exchanger 27 and the bath heat exchanger 28, which have different paths, are arranged side by side in one 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 heat absorption pipes 33, 33... formed in a serpentine shape. As shown in Fig. 4, both ends of each heat absorption pipe 33 are connected to an inlet header 34 and an outlet header 35 provided at the front and rear of the left side surface of the upper casing 19, 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 receiver 36 which is flat at the front and rear. An exhaust port 37 is connected to the front side of the drain receiver 36 so as to face 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 routed forward on the right side of the intermediate casing 18 and is connected to the upstream end of the lower stage 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 tube 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, loops 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 intermediate 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 wound around the combustion chamber 16, straddling the lower casing 17 and the middle casing 18. The resin sheet 50 is wound around the inner surfaces of the left and right side plates 7A, 7B and the back plate 8 on the outside of each pipe, so that the resin sheet 50 is not in contact with the combustion chamber 16.
A continuous conductive pattern 51 that extends in the longitudinal direction while meandering back and forth in the width direction is printed on the resin sheet 50 over the entire longitudinal length. Both ends of the conductive pattern 51 are electrically connected to an electrical board 66 described later to form an overheating prevention device. When abnormal overheating of the lower casing 17 or the middle casing 18 causes cracks or holes to form and combustion exhaust gas is ejected, the resin sheet 50 melts and the conductive pattern 51 breaks, causing the resistance value to suddenly increase or become infinite. The electrical board 66 detects the change in resistance value and stops the supply of fuel gas to extinguish the burner unit 20.

A neutralizer 55 is disposed in front of the combustion chamber 16. The neutralizer 55 is a box having a rectangular shape when viewed from the front, and is filled with a neutralizing agent (not shown). Drain discharge pipes 56, 56 connected to the front bottom surface of the upper casing 19 and the drain receiver 36 are connected to the upper surface of the neutralizer 55. A drain pipe 57 connected to the drain outlet 14 is connected to the lower surface of the neutralizer 55.
3, an upper portion of the neutralizer 55 is fixed to a bracket metal fitting 58 fixed downward from the middle casing 18 and the upper casing 19 via a mounting metal fitting 59 that is L-shaped in a side view. A lower portion of the neutralizer 55 is fixed to a fixing bar 60 that is fixed to the lower casing 17 in front 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 of the external pipe connected to the hot water outlet 10 is opened to allow water to flow into the appliance and the flowing water is detected by a hot water supply amount sensor provided in the water supply pipe 40, the controller 65 rotates the combustion fan 22 for a predetermined time to discharge the combustion exhaust gas accumulated in the combustion chamber 16 (pre-purge). After that, 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 degree, supplies gas to the burner unit 20, and operates the igniter to ignite the burner unit 20.
As a result, the water supplied from the water supply pipe 40 exchanges heat with the 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 drainage generated at this time is recovered 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 while flowing through the hot water side heat transfer pipe 30, exchanges heat with the combustion exhaust gas from the burner unit 20 to recover sensible heat. The hot water thus heated 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 a 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 and 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 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 period of time (post-purge).

On the other hand, when the automatic switch of the hot water supply remote control or the bath remote control is pressed, the electrical board 66 opens the drop water solenoid valve provided in the drop pipe 47 to pass water through the hot water supply primary heat exchanger 27 and the hot water supply secondary heat exchanger 32, and combusts 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 board 66 closes the drop water solenoid valve to stop the water flow and extinguishes the burner unit 20.
Next, the electrical board 66 operates the pump 46 to circulate the 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 with thermistors installed in the bath return pipe 45 and the bath supply pipe 48, and when it confirms that the temperature has dropped from the set temperature, it ignites the burner unit 20 as in the case of hot water supply, and supplies combustion air by the combustion fan 22. 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 surface 67a on the front side and is a horizontally long rectangle 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 facing upward on the top surface of the storage case 67. A small hole 70 is formed through each mounting piece 69. A vent hole 67b is cut out from the front end and formed in the center of the left and right sides of the top surface of the storage case 67 in front of the mounting pieces 69, 69.
Three cover mounting parts 71A, 71A, 71B are provided on the left and right outer sides of the mounting pieces 69, 69. The cover mounting parts 71A, 71A are arranged on the left and right outer sides of the ventilation hole 67b, and the cover mounting part 71B is arranged in the left and right center behind the ventilation hole 67b. Each of the cover mounting parts 71A on the left and right outer sides is a rectangular protrusion in plan view that extends in the front-rear direction with a flat upper surface. The cover mounting part 71B is made of a pair of left and right walls that extend in the front-rear direction. The rear end of the cover mounting part 71B is located further rearward than the rear end of the cover mounting part 71A. At the rear end of each of the cover mounting parts 71A, 71B, an upper locking part 72a that is a gate-shaped protrusion in a front view is protruded upward. At the front side of each cover mounting part 71A, three support protrusions 72b that rise to the same height as the upper locking part 72a and have flat upper surfaces are formed at two locations on the left side and one location on the right side. Further, a drain groove 73 is formed on the upper surface of each cover mounting portion 71A, sloping downward from the center in the front-rear direction toward the rear. The drain groove 73 is formed below the upper locking portion 72a to the rear end of the cover mounting portion 71A.

A pair of left and right support parts 74, 74 are formed on the underside of the storage case 67. Each support part 74 is in the shape of a block extending downward from the underside of the storage case 67. A conical locking projection 75 that tapers downward is formed on the underside of each support part 74. A pair of through holes 76, 76 corresponding to the locking projections 75, 75 are formed in the bottom plate 6 of the box body 3.
A pair of left and right lower locking portions 77, 77 (FIGS. 2 and 9) are formed on the underside of the storage case 67 on the left and right outer sides of the left and right support portions 74, 74. Each lower locking portion 77 is a bamboo shoot-shaped protrusion formed downward with a lower end having a larger diameter than the upper portion. A plurality of hooks 78, 78... for locking cables connected to the electrical board 66 are formed on the underside of the storage case 67.
The electrical board 66 is a printed circuit board having a horizontally elongated rectangular shape when viewed from the front, and various control parts such as a microcomputer and memory are mounted on the front surface of the printed circuit board. The electrical board 66 is fitted into the inner bottom surface of the storage case 67 from the front and positioned.

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 in the shape of a band that is slightly larger in both the front-rear and left-right directions than the top surface of the storage case 67. A pair of left and right notches 82, 82 are formed at the rear end of the top plate 80, located above the left and right mounting pieces 69, 69.
Three notches 83, 83... are formed between the cutouts 82, 82 and on the left and right outer sides. Each notch 83 extends in the left-right direction corresponding to each upper locking portion 72a of the cover mounting portions 71A, 71B. Square holes 84, 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 upper locking portion 72a to be inserted therethrough.
The front plate 81 is connected downward from the front end of the upper plate 80 and has a generally rectangular shape in front view that covers the opening surface 67a of the storage case 67. A pair of left and right bent pieces 85, 85 that are bent backwards are formed at the left and right lower corners of the front plate 81. A locking hole 86 is formed in each of the bent pieces 85. The locking holes 86 correspond to the lower locking parts 77 provided on the underside of the storage case 67.
Rearward folded-back portions 87, 87 are formed in the up-down direction on the left and right side edges of the front panel 81. The folded-back portions 87, 87 are provided at 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 that of the one that fixes the neutralizer 55 to the bracket bracket 58, and includes an upper plate 90, a middle plate 91, and a lower plate 92. The upper plate 90 is a strip-shaped plate extending in the vertical direction, and has a through hole 93 formed therein. The middle plate 91 is a strip-shaped 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-shaped 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 screwing 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 projections 75, 75 of the left and right support parts 74, 74 from above into the through holes 76, 76 of the bottom plate 6. In this state, the upper plate parts 90, 90 of the mounting brackets 59, 59 are positioned on the front surface of the fixed bar 60, and the screws 96, 96 that have been passed through the through holes 93, 93 from the front are screwed into the screw holes 97, 97 provided in the fixed bar 60, thereby fixing the case to the fixed bar 60.

Then, the upper plate 80 of the cover 68 is placed on the upper surface of the storage case 67 from above the front side of the storage case 67. At this time, the three notches 83, 83... of the upper plate 80 are aligned with the upper locking portions 72a of the three cover mounting portions 71A, 71A, 71B of the storage case 67, respectively, and each upper locking portion 72a is penetrated into the corresponding notch 83 from below. Then, as shown in FIG. 10, both ends of the upper locking portion 72a fit into the square holes 84, 84 at both ends of the notch 83, and the notch 83 is closed. At this time, the support protrusions 72b, 72b provided at the front ends of the left and right cover mounting portions 71A, 71A abut against the underside of the front end side of the upper plate 80, so that the upper plate 80 is inclined in such a manner that the rear end that locks with the upper locking portion 72a is lower than the front end that abuts against the support protrusions 72b, as shown in FIG. 11. In this state, the rear end of the top plate 80 is positioned above the rear end of the top surface of the storage case 67, and the front plate 81 covers the opening surface 67a of the storage case 67 from the front. Then, when the left and right lower locking portions 77 of the storage case 67 are inserted and locked into the locking holes 86 of the left and right bent pieces 85, the front plate 81 is positioned so as to close the opening surface 67a 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, the water droplets flow to the rear side of the upper plate 80, which is inclined downward toward the rear, as shown by the dotted arrow a in Fig. 11, and fall from the rear end of the upper plate 80 toward the rear end of the upper surface of the storage case 67. The water droplets then continue to fall downward along the back surface of the storage case 67.
Furthermore, even if water droplets that come into contact with the upper engaging portion 72a protruding from the upper plate 80 penetrate through the notch 83 due to capillary action into the gap between the upper plate 80 and the cover mounting portion 71A, as shown by the dotted arrow b in Figure 11, the water droplets flow rearward through the drain groove 73 provided on the upper surface of the cover mounting portion 71A and drop downward along the upper surface and rear surface of the storage case 67. This effectively prevents water droplets from penetrating from the front surface of the storage case 67 into the electrical board 66.

(Effect of disclosure regarding the controller)
The water heater 1 of the above-mentioned form contains within a housing 2 a combustion chamber 16 having a burner 21, hot water primary and secondary heat exchangers 27, 32, and a bath heat exchanger 28, and a controller 65 for controlling the burner 21. The controller 65 includes an electrical board 66, a box-shaped storage case 67 which houses the electrical board 66 and is arranged vertically within the housing 2, with the top and bottom surfaces and a back surface (an example of a surface) connecting the top and bottom surfaces being closed surfaces, and the front surface opposite the back surface being an opening surface 67a, and a cover 68 which is attached to the top surface of the storage case 67 and closes the opening surface 67a of the storage case 67.
Further, an air vent 67b is formed on the top surface of the storage case 67, and an upper locking portion 72a to which the cover 68 can be locked is provided on the rear side of the air vent 67b.
The cover 68 has an upper plate 80 having a notch 83 and a square hole 84 (an example of a locked portion) with which the upper locking portion 72a can be locked, and a front plate 81 (an example of a vertical plate) that is formed integrally with the upper plate 80 and closes the opening surface 67a. When the upper locking portion 72a is locked in the notch 83 and the square hole 84, the upper plate 80 is in an inclined position that becomes lower as it moves from the opening surface 67a side toward the rear side.

With this configuration, even if rainwater or other water droplets fall on the controller 65, they are guided to the rear side of the storage case 67 by the top plate 80 of the cover 68, which slopes downward toward the rear. In addition, since the notch 83 and the square hole 84 are provided toward the rear, even if water droplets flowing on the top plate 80 flow from the notch 83 and the square hole 84 to the underside of the top plate 80 due to capillary action, they will flow directly to the rear side of the storage case 67 and fall. This prevents rainwater from entering the inside of the storage case 67 through the opening 67a and the ventilation hole 67b, improving the drip-proofing of the controller 65.

On the top surface of the storage case 67, closer to the opening surface 67a than the upper engaging portion 72a, a support protrusion 72b is provided which abuts against the underside of the front of the upper plate 80 which has the upper engaging portion 72a engaged with the notch 83 and the square hole 84, thereby supporting the front side of the upper plate 80 at a higher position than the rear side.
Therefore, the upper plate 80 can be reliably maintained in a downwardly inclined rearward position.
A lower locking portion 77 is provided on the underside of the storage case 67, while a folded piece 85 (an example of a folded portion) is formed on the front plate 81 of the cover 68 by bending it toward the underside of the storage case 67, and the folded piece 85 is provided with a locking hole 86 (an example of a second locked portion) with which the lower locking portion 77 can be locked. This prevents the lower part of the front plate 81 from shifting forward from the opening surface 67a, and ensures that the opening surface 67a is kept closed by the front plate 81.

(Explanation of modified examples)
The upper locking portion may not be gate-shaped but may be semicircular or the like. The cross-sectional shape of the upper locking portion may not be square but may be round or the like. Thus, both ends of the cut in the cover are not limited to square holes but may be appropriately changed to match the cross-sectional shape of the upper locking portion. The upper locking portion may be a bamboo shoot-shaped protrusion like the lower locking portion.
The engaged portion is not limited to the notch and square hole described above, but may be a slit that opens through the thickness of the upper engaging portion, or multiple radial slits connected at the center, and can be modified as appropriate to match the shape of the upper engaging portion.
The number of upper locking portions and locked portions is not limited to three, and may be increased or decreased as appropriate as long as the cover can be fixed.
The number, positions and shapes of the support protrusions are not limited to those described above and may be changed as appropriate. For example, the upper surfaces of the support protrusions may be inclined downward toward the closed surface of the storage case.
The drain groove provided in the cover mounting part is not limited to a structure inclined from the center in the front-to-rear direction of the upper surface of the cover mounting part. It may be inclined over the entire upper surface of the cover mounting part. The cover mounting part may not protrude from the upper surface of the storage case, and the upper engagement part, support protrusion, and drain groove may be provided on the flat upper surface. However, one or both of the support protrusion and the drain groove may be omitted.
The locking structure between the folded portion of the cover and the lower locking portion of the storage case may be provided on either the left or right side, or may be omitted.

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-back direction, for example. Therefore, when the opening of the storage case is oriented horizontally, the upper plate of the cover is inclined left-right.
The controller may be vertically long instead of horizontally long.
The mounting of the storage case in the housing is not limited to the above-mentioned structure. For example, the number of mounting brackets may be increased or decreased at the upper part 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 lower part of the storage case, the support part may be eliminated and only a locking protrusion may be provided protruding from the lower surface of the storage case. The lower part of the storage case may be fixed to the housing with a screw without using the locking protrusion.

In the above embodiment, the primary heat exchanger and the secondary heat exchanger 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 arranged in a single casing to form a one-can, two-channel water heater, but the present disclosure is not limited to the one-can, two-channel water heater. For example, a two-can, two-channel water heater may be used in which a hot water supply combustion chamber having a hot water supply heat exchanger and a bath (or heating, etc.) combustion chamber having a bath (or heating, etc.) heat exchanger are separately provided, and the bath (or heating, etc.) circuit is formed separately from the hot water supply circuit.
However, the present disclosure can be applied to a water heater that does not include a heat exchanger for a bath or a heater, and that only includes 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: Primary hot water heat exchanger, 28: Bath heat exchanger, 32: Secondary hot water heat exchanger, 40: Water supply pipe, 41: Relay pipe, 42: Outlet hot water pipe, 45: Bath return pipe, 48: Bath supply pipe, 5 0: Resin sheet, 55: Neutralizer, 59: Mounting bracket, 65: Controller, 66: Electrical board, 67: Storage case, 67a: Opening surface, 67b: Ventilation hole, 68: Cover, 69: Mounting piece, 71A, 71B: Cover mounting part, 72a: Upper locking part, 72b: Support protrusion, 73: Drainage groove, 77: Lower locking part, 80: Upper plate, 81: Front plate, 83: Notch, 84: Square hole, 85: Bent piece, 86: Locking hole.

Claims (3)

A combustion chamber having a burner and a heat exchanger, and a controller for controlling the burner are housed in the housing;
The controller includes an electrical board, a box-shaped storage case that houses the electrical board and is vertically placed in the housing, with an upper surface, a lower surface, and a surface connecting the upper surface and the lower surface being closed surfaces, and a surface opposite to the one surface being an open surface, and a cover that is attached to the upper surface of the storage case and closes the open surface,
a ventilation hole is formed on an upper surface of the storage case, and an upper locking portion to which the cover can be locked is provided on the one surface side of the ventilation hole;
The cover has an upper plate having an engaging portion to which the upper engaging portion can engage, and a vertical plate that is formed integrally with the upper plate and closes the opening surface, and when the upper engaging portion is engaged with the engaging portion, the upper plate is in an inclined position that becomes lower as it moves from the opening surface side toward the one surface side. The water heater according to claim 1, characterized in that a support protrusion is provided on the upper surface of the storage case closer to the opening side than the upper engaging portion, which abuts against the underside of the opening side of the upper plate that engages the upper engaging portion with the engaged portion, and supports the opening side of the upper plate at a higher position than the one side. The water heater according to claim 1 or 2, characterized in that a lower locking portion is provided on the underside of the storage case, while a bent portion is formed on the vertical plate of the cover by bending it toward the underside of the storage case, and the bent portion is provided with a second lockable portion to which the lower locking portion can be locked.

Images