Method for assembling water heater, and exhaust unit for water heater

Abstract

To provide a method for assembling a water heater and an exhaust unit for the water heater which can prevent a false assembly by screws.SOLUTION: In a conventional water heater, an exhaust top is screwed to a fixing flange 41 of the exhaust hood 4. When a water hearer is assembled using a housing having a longer front-rear width than conventional art, a fixing panel 7 for attaching between the exhaust hood 4 and the exhaust top and an extension adapter are prepared. The fixing panel 7 includes: a plurality of fixing holes 71 used in a panel fixing process; and a plurality of fixing holes used in an adapter fixing process. The panel fixing process is a process for fixing the fixing panel 7 to the fixing flange 41 of the exhaust hood 4. The adapter fixing process is a process for fixing the extension adapter to the fixing panel 7. A mark 75 is engraved in the vicinity of each of the plurality of fixing holes 71 on a front dace of the fixing panel 7. In the panel fixing process, an operator can easily distinguish the fixing hole 71 by the mark 75.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] The present invention relates to an assembly method of a hot water device and an exhaust unit of a hot water device.

Background Art

[0002] Conventionally, a burner, a heat exchanger, and an exhaust part are attached inside a casing of a water heater (see, for example, Patent Document 1). A cover is attached to the front surface of the casing that opens. The exhaust port of the exhaust part opens forward. An insertion port is provided in the cover at a position facing the exhaust port of the exhaust part. A cylindrical exhaust top is screwed to the peripheral edge of the exhaust port of the heat exchanger, and the front end of the exhaust top is inserted into the insertion port of the cover from the rear.

[0003] Among water heaters having such a configuration, there are similar models with different sizes of heat exchangers. In a water heater equipped with a heat exchanger of a larger size than normal, a larger-sized casing is used instead of a normal-sized casing. The depth (front-rear width) of the larger-sized casing is longer than that of the normal-sized casing. On the other hand, since the exhaust part is a common part, as a result, the distance between the exhaust port and the insertion port of the cover attached to the front surface of the larger-sized casing becomes longer. For this reason, there arises a problem that the front end of the exhaust top screwed to the peripheral edge of the exhaust port cannot reach the insertion port.

[0004] To solve this problem, a fixing plate is screwed to the peripheral edge of the exhaust port, and a cylindrical extension adapter extending in the front-rear direction is screwed to the fixing plate. Then, by screwing the exhaust top to the screwed extension adapter, the front end of the exhaust top can be inserted into the insertion port from the rear.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The fixing plate is provided with fixing holes for screwing around the periphery of the exhaust port and fixing holes for screwing the extension adapter to the fixing plate. Therefore, during the assembly or maintenance of the water heater in the factory, there was a possibility that the operator might mistake the fixing holes to be screwed according to multiple steps and assemble them incorrectly.

[0007] An object of the present invention is to provide an assembly method for a hot water device that can prevent assembly errors due to screwing, and an exhaust unit for a hot water device.

Means for Solving the Problems

[0008] The method for assembling a hot water device according to claim 1 includes a heat exchanger having a heat transfer pipe for heating water flow with combustion exhaust from a burner, an exhaust section for discharging the combustion exhaust that has passed through the heat exchanger to the outside, a first housing with an open front for mounting the heat exchanger and the exhaust section inside, and a first cover attached to the open front of the first housing. The first cover is provided with a first insertion opening at a position opposite to an exhaust opening that opens in front of the exhaust section. When changing from the first housing to a second housing that is longer in the front-rear width than the first housing, a second cover is attached to the open front of the second housing, and the distance from the exhaust opening to a second insertion opening provided at a position opposite to the exhaust opening of the second cover is longer than the distance from the exhaust opening to the first insertion opening. The method for assembling the hot water device with the first housing includes a first step of positioning an exhaust top provided cylindrically with respect to the peripheral edge of the exhaust opening of the exhaust section and screwing it in alignment with the position of a second fixing hole provided in the exhaust top with respect to the position of a first fixing hole provided in the peripheral edge, and a second step of attaching the first cover to the open front of the first housing with the exhaust top screwed to the peripheral edge in the first step and inserting the front end portion of the exhaust top into the first insertion opening from the rear. When assembling the hot water device with the second housing, a fixing plate having an opening at a portion opposite to the exhaust opening, a third fixing hole corresponding to the first fixing hole, a fourth fixing hole at a position different from the third fixing hole, and a mark for discriminating between the third fixing hole and the fourth fixing hole, and a cylindrical extension adapter extending in the front-rear direction and having a fifth fixing hole corresponding to the fourth fixing hole and a sixth fixing hole corresponding to the second fixing hole are prepared. A third step of positioning the fixing plate at the peripheral edge of the exhaust opening and screwing it in alignment with the position of the third fixing hole provided in the fixing plate and discriminated by the mark with respect to the position of the first fixing hole provided in the peripheral edge, a fourth step of positioning the extension adapter on the fixing plate and screwing it in alignment with the position of the fifth fixing hole provided in the extension adapter with respect to the position of the fourth fixing hole provided in the fixing plate, and positioning the exhaust top with respect to the extension adapter andA fifth step of screwing while aligning the position of the second fixing hole provided in the exhaust top, and in the fourth step, the extension adapter is screwed to the fixing plate, and in the fifth step, with the exhaust top screwed to the extension adapter, the second cover is attached to the front surface of the second housing that opens, and a sixth step of inserting the front end portion of the exhaust top into the second insertion port from the rear.

[0009] In the method for assembling the hot water device according to claim 2, the mark may be provided adjacent to the third fixing hole.

[0010] In the method for assembling the hot water device according to claim 3, the mark may be engraved on the front surface of the fixing plate.

[0011] The exhaust unit of the hot water device according to claim 4 includes an exhaust section having an exhaust port for discharging the combustion exhaust that has passed through a heat exchanger that heats the passing water with the combustion exhaust from the burner to the outside, and a cylindrical exhaust top that is directly or indirectly fixed to the peripheral edge of the exhaust section. The front surface is open, and a first housing for attaching the heat exchanger and the exhaust section inside, and a first cover attached to the front surface of the first housing that opens, and having a first insertion port at a position opposite to the exhaust port of the exhaust section where the front end of the exhaust top is inserted from the rear. A first hot water device, or a second housing that is longer in the front-rear width than the first housing from the first housing, and a second cover attached to the front surface of the second housing that opens. The distance from the exhaust port to a second insertion port provided at a position opposite to the exhaust port of the second cover is longer than the distance from the exhaust port to the first insertion port. The exhaust unit of the hot water device provided in any of the second hot water devices. When provided in the first hot water device, the second fixing hole provided in the exhaust top is positioned with respect to the first fixing hole provided in the peripheral edge of the exhaust section, and the exhaust top is screwed to the peripheral edge. On the other hand, when provided in the second hot water device, it further includes a fixing plate and an extension adapter interposed between the exhaust section and the exhaust top. The fixing plate has an opening in a portion opposite to the exhaust port. The extension adapter has a cylindrical shape extending in the front-rear direction. The fixing plate is provided with a third fixing hole corresponding to the first fixing hole, a fourth fixing hole at a position different from the third fixing hole, and a mark for discriminating the third fixing hole or the fourth fixing hole. The extension adapter is provided with a fifth fixing hole corresponding to the fourth fixing hole and a sixth fixing hole corresponding to the second fixing hole. The third fixing hole provided in the fixing plate and discriminated by the mark is positioned with respect to the first fixing hole provided in the peripheral edge of the exhaust port, and the fixing plate is screwed to the peripheral edge. The fifth fixing hole provided in the extension adapter is positioned with respect to the fourth fixing hole provided in the fixing plate, and the extension adapter is screwed to the fixing plate. The second fixing hole provided in the exhaust top is positioned with respect to the position of the sixth fixing hole provided in the extension adapter, and the exhaust top is screwed to the extension adapter.The second cover is attached to the front surface of the second housing where the extension adapter is screwed to the fixed plate and the exhaust top is screwed to the extension adapter, and the front end portion of the exhaust top is inserted into the second insertion port from the rear.

[0012] The extension adapter of the exhaust unit of the hot water device according to claim 5 includes a plate-shaped fixed portion that abuts and is fixed to the fixed plate. The fixed portion is provided at a position corresponding to the fifth fixing hole and the third fixing hole of the fixed plate, and may include a relief hole for avoiding interference with the head of the screw fastened to the third fixing hole.

Advantages of the Invention

[0013] According to the method for assembling the hot water device of claim 1, a mark for discriminating the third fixing hole or the fourth fixing hole is provided on the front surface of the fixed plate. When changing from the first housing to the second housing and screwing the fixed plate to the peripheral edge of the insertion port of the exhaust portion, the operator can screw the third fixing hole to the first fixing hole without misidentifying it as the fourth fixing hole by checking the mark, so that the fixed plate can be correctly fixed to the peripheral edge of the insertion port. Further, after screwing the third fixing hole, by checking the mark, it can be easily visually determined whether the third fixing hole is correctly screwed or not mistakenly screwed to the fourth fixing hole.

[0014] According to the method for assembling the hot water device of claim 2, the third fixing hole can be easily discriminated on the front surface of the fixed plate.

[0015] According to the method for assembling the hot water device of claim 3, it is possible to prevent the mark from disappearing from the front surface of the fixed plate. Further, since the mark can be formed without increasing the pressing process of the fixed plate, it can be implemented at low cost.

[0016] According to the exhaust unit of the hot water device of claim 4, a mark for discriminating the third fixing hole or the fourth fixing hole is provided on the front surface of the fixing plate. When changing from the first housing to the second housing and screwing the fixing plate to the peripheral edge of the insertion port of the exhaust part, the operator can screw the third fixing hole to the first fixing hole without mistake by checking the mark, so that the fixing plate can be correctly fixed to the peripheral edge of the insertion port. Further, after screwing the third fixing hole, by checking the mark, it can be easily visually determined whether the third fixing hole is correctly screwed or not mistakenly screwed to the fourth fixing hole.

[0017] According to the exhaust unit of the hot water device of claim 5, when the fixed part of the extension adapter is brought into contact with the fixing plate, the recess provided in the fixed part avoids interference with the head of the screw previously fastened to the third fixing hole of the fixing plate, so that the fixed part can be brought into contact with the fixing plate in a state of being in close contact therewith.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described. The device configurations and the like described below are not limited to only those unless otherwise specifically described, but are merely illustrative examples. The drawings are used to explain the technical features that the present invention can adopt. In this embodiment, the front-rear, left-right, and up-down directions shown in the figures will be used for the explanation. Also, the scales of the respective figures do not necessarily match each other, and are appropriately enlarged or reduced according to the object to be illustrated.

[0020] Referring to FIGS. 1 to 6, the configuration of the water heater 1 will be described. As shown in FIGS. 1 and 2, the water heater 1 includes a housing 2 and a front cover 9. An opening 21 (see FIG. 3) is provided on the front surface of the housing 2. The front-rear width of the housing 2 is L1 (see FIG. 2). The front cover 9 is detachable from the front surface of the housing 2 where it opens. An insertion port 91 is provided at the upper part of the front cover 9. The insertion port 91 is a substantially rectangular shape that is horizontally long when viewed from the front. The cylindrical portion 51 of the exhaust top 5 described later is inserted into the insertion port 91 from the rear, and its front end portion protrudes forward of the front cover 9 (see FIG. 2). An air intake port 92 is provided at the lower part of the front cover 9. Although not shown, on the bottom plate of the housing 2, a hot water outlet connected to an external hot water tap, a water inlet to which a water pipe is connected from the outside, and a gas inlet to which a gas pipe is connected from the outside are provided respectively.

[0021] As shown in FIG. 3, an upper portion inside the housing 2 is provided with a heat exchanger 3 and an exhaust unit 15. The exhaust unit 15 is fixed to the upper part of the heat exchanger 3 and includes an exhaust hood 4 and an exhaust top 5. A combustion part (not shown) and an air supply fan are provided below the heat exchanger 3. The combustion part includes a plurality of burners arranged side by side in the left-right direction in a case (not shown). The air supply fan is disposed below the combustion part and supplies combustion air to the plurality of burners.

[0022] As shown in FIGS. 4 and 5, the heat exchanger 3 includes a casing 30, fins (not shown), and a plurality of heat transfer tubes 35. The casing 30 is in a substantially rectangular tube shape that penetrates in the vertical direction and includes a front wall 31, a right wall 32, a left wall (not shown), and a rear wall 34 (see FIG. 5). A flange portion 33 that protrudes outward is provided at the lower end portion of the casing 30. The flange portion 33 is clamped and fixed to the upper part of the case of the combustion part. The fins are provided inside the casing 30 and are stacked in a plurality of sheets at a predetermined interval in the front-rear direction.

[0023] The plurality of heat transfer tubes 35 penetrate the front wall 31, the fins, and the rear wall 34 in the front-rear direction and are arranged parallel to each other in the left-right direction. By connecting adjacent heat transfer tubes 35 to each other with a U-shaped connecting tube, a series of pipe bodies that are connected in a meandering shape on a substantially horizontal plane are formed. The upstream end portion of the pipe body protrudes rearward from the right side of the rear wall 34, and the downstream end portion of the water inlet pipe 11 (see FIG. 3) is connected to the water inlet 36 formed at one end portion thereof. On the other hand, the downstream end portion of the pipe body protrudes forward from the left side of the front wall 31, and a hot water outlet pipe 12 (see FIG. 3) is connected to the hot water outlet 37 formed at the other end portion thereof. A bypass pipe 13 (see FIG. 3) is connected between the water inlet pipe 11 and the hot water outlet pipe 12. Inside the casing 30, combustion exhaust from the combustion part passes through the gaps between the heat transfer tubes 35, so that heat exchange is performed between the water flowing through the heat transfer tubes 35, and the water flowing through the heat transfer tubes 35 is heated.

[0024] As shown in FIG. 6, the exhaust hood 4 is fixed to the upper part of the casing 30 of the heat exchanger 3. The exhaust hood 4 has a shape that bulges upward at the rear and gradually becomes lower toward the front. At the lower end of the exhaust hood 4, a flange portion 47 that protrudes outward is provided. The flange portion 47 is caulked and fixed to the upper part of the case of the combustion part. The front end of the exhaust hood 4 protrudes forward from the heat exchanger 3 (see FIG. 5). A rectifying plate 46 is provided inside the exhaust hood 4. The rectifying plate 46 forms an exhaust passage for the combustion exhaust. An exhaust port 40 (see FIG. 6) is provided at the front end of the exhaust hood 4. The exhaust port 40 is substantially rectangular in shape and long in the left-right direction when viewed from the front. A fixing flange 41 is provided along the peripheral edge of the exhaust port 40.

[0025] The fixing flange 41 protrudes outward from the peripheral edge of the exhaust port 40 and is substantially rectangular frame-shaped and long in the left-right direction when viewed from the front. The fixing flange 41 includes an upper side portion 411 and a lower side portion 412. The upper side portion 411 forms the upper side portion and the left and right side portions of the fixing flange 41 and is reverse U-shaped when viewed from the front. Four fixing holes 43 are provided in the upper side portion 411 at intervals in the left-right direction. The lower side portion 412 extends in the left-right direction and forms the lower side portion of the fixing flange 41. Four fixing holes 44 are provided in the lower side portion 412 at intervals in the left-right direction. The exhaust top 5 is fixed to such a fixing flange 41 from the front.

[0026] The exhaust top 5 includes a cylindrical portion 51 and a fixing flange 52. The cylindrical portion 51 extends in the front-rear direction and is substantially cylindrical with a short axis that is long in the left-right direction when viewed from the front. A closing plate 511 is provided at the front end of the cylindrical portion 51 where it opens. The closing plate 511 closes the left and right sides of the opening at the front end of the cylindrical portion 51. An exhaust outlet 53 is provided substantially at the center of the closing plate 511. The exhaust outlet 53 is substantially oval in shape and long in the left-right direction when viewed from the front.

[0027] The fixed flange 52 is provided at the rear end of the cylindrical portion 51 and protrudes outward. The fixed flange 52 is in a substantially rectangular frame shape that is long in the left-right direction when viewed from the front. A protruding piece 54 is provided along the outer end of the fixed flange 52. The protruding piece 54 protrudes rearward from the outer end of the fixed flange 52. The fixed flange 52 includes an upper portion 521 and a lower portion 522. Four fixing holes 55 are provided in the upper portion 521 at intervals in the left-right direction. The four fixing holes 55 respectively correspond to the four fixing holes 43 provided in the upper portion 411 of the fixed flange 41 of the exhaust hood 4. Four fixing holes 56 are provided in the lower portion 522 at intervals in the left-right direction. The four fixing holes 56 respectively correspond to the four fixing holes 44 provided in the lower portion 412 of the fixed flange 41 of the exhaust hood 4.

[0028] Referring to FIG. 6, an example of an assembling method of the exhaust unit 15 and an attaching method of the front cover 9 to the housing 2 will be described.

[0029] <Top Fixing Step> The top fixing step is a step of screwing the exhaust top 5 to the fixed flange 41 of the exhaust hood 4. With the heat exchanger 3 and the exhaust hood 4 attached in the housing 2, the operator abuts the fixed flange 52 of the exhaust top 5 from the front against the fixed flange 41 of the exhaust hood 4 via a resin packing (not shown). At this time, the fixed flange 41 is disposed inside the protruding piece 54 provided at the outer end of the fixed flange 52. Thereby, the rear surface of the upper portion 521 of the fixed flange 52 abuts against the front surface of the upper portion 411 of the fixed flange 41. The rear surface of the lower portion 522 of the fixed flange 52 abuts against the front surface of the lower portion 412 of the fixed flange 41.

[0030] Furthermore, for each position of the four fixing holes 43 provided in the upper part 411, align the positions of the four fixing holes 55 provided in the upper part 521. For each position of the four fixing holes 44 provided in the lower part 412, align the positions of the four fixing holes 56 provided in the lower part 522. At this time, when viewing the exhaust top 5 from the front side, the four fixing holes 55 overlap with the four fixing holes 43 of the fixing flange 41, and the four fixing holes 56 overlap with the four fixing holes 44 of the fixing flange 41.

[0031] In this state, insert four screws 94 from the front into the four fixing holes 55 provided in the upper part 521 and fasten them to the four fixing holes 43 provided in the upper part 411. Further, insert four screws 94 from the front into the four fixing holes 56 provided in the lower part 522 and fasten them to the four fixing holes 44 provided in the lower part 412. Thereby, the fixing flange 52 of the exhaust top 5 is fixed to the fixing flange 41 of the exhaust hood 4 (see FIGS. 3 to 5).

[0032] <Cover attachment process> The cover attachment process is a process of screwing the front cover 9 to the front surface of the housing 2 that opens. When fixing the front cover 9 to the front surface of the housing 2 that opens with screws (not shown), insert the front end side of the cylindrical portion 51 of the exhaust top 5 from the rear into the inside of the insertion port 91 provided in the front cover 9. As shown in FIGS. 1 and 2, in a state where the front cover 9 is fixed to the front surface of the housing 2, the front end portion of the cylindrical portion 51 of the exhaust top 5 protrudes forward from the insertion port 91 of the front cover 9.

[0033] In the exhaust unit 15 of such a water heater 1, the combustion exhaust that has flowed into the exhaust hood 4 is guided forward by the rectifying plate 46 and flows into the cylindrical portion 51 of the exhaust top 5 from the exhaust port 40. Further, the combustion exhaust flows forward in the cylindrical portion 51 and is discharged to the outside of the housing 2.

[0034] Referring to FIGS. 7 to 16, the configuration of the water heater 100 will be described. The water heater 100 shown in FIG. 7 is a similar model to the water heater 1 and shares some of the components of the water heater 1. Therefore, in the following description, for the components common to the water heater 1, the same reference numerals as those of the water heater 1 will be used to simplify or omit the description.

[0035] As shown in FIGS. 7 and 8, the water heater 100 includes a housing 120 and a front cover 190. The water heater 100 includes a heat exchanger 6 (see FIG. 9) that is larger in size than the heat exchanger 3 of the water heater 1. Since the size of the heat exchanger 6 is large, the size of the housing 120 for mounting it inside is larger than the size of the housing 2 of the water heater 1. For example, the front-to-rear width L2 (see FIG. 8) of the housing 120 is longer than the front-to-rear width L1 (see FIG. 2) of the housing 2. An opening 121 (see FIG. 9) is provided on the front surface of the housing 120.

[0036] The front cover 190 is detachable from the front surface of the housing 120 where the opening is located. As shown in FIG. 7, an insertion port 191 is provided at the upper part of the front cover 190. The insertion port 191 is substantially rectangular in shape with a horizontally long front view. The cylindrical portion 51 of the exhaust top 5 is inserted into the insertion port 191 from the rear, and its front end portion protrudes forward of the front cover 190 (see FIG. 8). An air intake port 192 is provided at the lower part of the front cover 190.

[0037] As shown in FIG. 9, a heat exchanger 6 and an exhaust unit 150 are provided on the upper side inside the housing 120. The exhaust unit 150 is fixed to the upper part of the heat exchanger 6. The configuration of the exhaust unit 150 will be described later. Below the heat exchanger 6, a combustion part and an air supply fan identical to those of the water heater 1 (not shown) are provided.

[0038] The heat exchanger 6 includes a casing 60, fins (not shown), and a plurality of heat transfer tubes 65. The casing 60 is in a substantially rectangular tube shape that penetrates in the vertical direction, and includes a front wall 61, a right wall 62, a left wall (not shown), and a rear wall 64 (see FIG. 11). The lateral width and the depth (front-rear width) of the casing 60 are substantially the same as the lateral width and the depth of the casing 30 of the heat exchanger 3. The height of the casing 60 is higher than the height of the casing 30. A flange portion 63 that protrudes outward is provided at the lower end portion of the casing 60. The flange portion 63 is clamped and screwed to the upper portion of the case of the combustion section. The fins are provided in the casing 60 and are stacked in a plurality of sheets at a predetermined interval in the front-rear direction.

[0039] The plurality of heat transfer tubes 65 penetrate the front wall 61, the rear wall 64, and the fins in the front-rear direction and are arranged parallel to each other in the left-right direction. By connecting adjacent heat transfer tubes 65 to each other with a U-shaped connecting tube, a series of tube bodies that are meandering in a substantially horizontal plane are formed in two upper and lower stages. Therefore, the tube body formed by the plurality of heat transfer tubes 65 is longer than the tube body formed by the plurality of heat transfer tubes 35 of the heat exchanger 3.

[0040] As shown in FIG. 11, the upstream end portion of the tube body formed by the plurality of heat transfer tubes 65 protrudes rearward from the lower right side of the rear wall 64, and the downstream end portion of the water inlet pipe 127 (see FIG. 9) is connected to the water inlet 66 thereof. On the other hand, the downstream end portion of the tube body protrudes forward from the upper left side of the front wall 61, and the hot water outlet pipe 128 (see FIG. 9) is connected to the hot water outlet 67 thereof. A bypass pipe 129 (see FIG. 9) is connected between the water inlet pipe 127 and the hot water outlet pipe 128. Inside the casing 60, the combustion exhaust gas from the combustion section passes through the gaps between the heat transfer tubes 65, so that heat exchange is performed between the water flowing through the heat transfer tubes 65, and the water flowing through the heat transfer tubes 65 is heated. As described above, since the tube body formed by the plurality of heat transfer tubes 65 is longer than the tube body formed by the plurality of heat transfer tubes 35 of the heat exchanger 3, the heating capacity of the heat exchanger 6 is higher than the heating capacity of the heat exchanger 3.

[0041] Referring to FIGS. 12 to 16, the configuration of the exhaust unit 150 will be described. As shown in FIG. 12, the exhaust unit 150 includes an exhaust hood 4, a fixing plate 7, an extension adapter 8, and an exhaust top 5. The exhaust hood 4 and the exhaust top 5 are the same components as those of the water heater 1. As described above, the depth of the housing 120 is longer than the depth of the housing 2. Therefore, when the exhaust top 5 is fixed to the fixing flange 41 of the exhaust hood 4 like the water heater 1, the distance between the insertion port 191 of the front cover 190 fixed to the front surface of the housing 120 and the exhaust outlet 53 of the exhaust top 5 is longer than the distance between the insertion port 91 of the front cover 9 of the water heater 1 and the exhaust outlet 53 of the exhaust top 5.

[0042] Therefore, when assembling the water heater 100, the exhaust unit 150 is installed in the housing 120 instead of the exhaust unit 15. Since the exhaust unit 150 includes an extension adapter 8 between the exhaust hood 4 and the exhaust top 5, the position of the exhaust top 5 can be arranged forward compared to the position of the exhaust top 5 of the exhaust unit 15 (see FIG. 5).

[0043] Referring to FIG. 13, the shape of the fixing plate 7 will be described. The fixing plate 7 is a metal plate having a shape in which four corners of a rectangle that is long in the left-right direction in a front view are cut off obliquely. A plurality of protruding pieces 77 protruding forward are provided on the outer edge of the fixing plate 7 so as to surround the front surface of the fixing plate 7. At the center of the fixing plate 7, at a position corresponding to the exhaust port 40 of the exhaust hood 4, a substantially oval opening 70 that is long in the left-right direction in a front view is provided. One protruding piece 78 protruding forward is provided on the upper edge portion of the inner edge portion of the opening 70, and three protruding pieces 78 protruding forward are provided at intervals in the left-right direction on the lower edge portion of the inner edge portion.

[0044] In the upper part of the fixing plate 7 above the opening 70, four fixing holes 71 and three fixing holes 72 are provided. The four fixing holes 71 are provided at intervals in the left - right direction in the vicinity of the upper edge of the opening 70. These four fixing holes 71 respectively correspond to the four fixing holes 43 provided in the upper part 411 of the fixing flange 41 of the exhaust hood 4. On the other hand, the three fixing holes 72 are provided at intervals in the left - right direction in the vicinity of the upper end of the fixing plate 7. On the other hand, in the lower part of the fixing plate 7 below the opening 70, four fixing holes 71 and three fixing holes 72 are also provided. The four fixing holes 71 are provided at intervals in the left - right direction in the vicinity of the lower edge of the opening 70. These four fixing holes 71 respectively correspond to the four fixing holes 44 provided in the lower part 412 of the fixing flange 41 of the exhaust hood 4. On the other hand, the three fixing holes 72 are provided at intervals in the left - right direction in the vicinity of the lower end of the fixing plate 7.

[0045] Thus, eight fixing holes 71 and six fixing holes 72 are provided in the fixing plate 7. The fixing holes 71 are the fixing holes to be screwed in the process of fixing the fixing plate 7 to the fixing flange 41 of the exhaust hood 4 (the plate fixing process described later). The fixing holes 72 are the fixing holes to be screwed in the process of fixing the extension adapter 8 to the fixing plate 7 (the adapter fixing process). Therefore, the operator needs to correctly select the fixing holes to be screwed according to the content of the process. However, since both the fixing holes 71 and 72 are round holes, it is difficult to identify them only by the position of the holes.

[0046] Therefore, in this embodiment, among the eight fixing holes 71 and six fixing holes 72 provided on the front surface 74 of the fixing plate 7, a "▽" mark 75 is engraved directly above each of the eight fixing holes 71 to be screwed in the same process. The mark 75 is a mark for identifying the fixing holes 71.

[0047] Referring to FIG. 15, the structure of the extension adapter 8 will be described. The extension adapter 8 includes a cylindrical portion 81. The cylindrical portion 81 extends in the front-rear direction and is a substantially rectangular cylinder that is long in the left-right direction. An insertion hole 811 that penetrates in the front-rear direction is provided inside the cylindrical portion 81. At the rear end portion of the cylindrical portion 81, a rear upper fixing flange 82, a rear lower fixing flange 83, a rear right flange 86, and a rear left flange 87 are provided. At the front end portion of the cylindrical portion 81, a front upper fixing flange 84, a front lower fixing flange 85, a front right flange 88, and a front left flange 89 are provided.

[0048] The rear upper fixing flange 82 protrudes upward from the upper end portion of the rear end portion of the cylindrical portion 81 and is a substantially rectangular shape that is long in the left-right direction when viewed from the rear. Near the upper end portion of the rear upper fixing flange 82, three fixing holes 821 are provided at intervals in the left-right direction. These three fixing holes 821 correspond to the positions of the three fixing holes 72 provided near the upper end portion of the fixing plate 7. Further, near the lower end portion of the rear upper fixing flange 82, four relief holes 845 are provided at intervals in the left-right direction. These four relief holes 845 correspond to the positions of the four fixing holes 71 provided near the upper edge portion of the opening 70 of the fixing plate 7 and are round holes having a diameter larger than that of the screw 95 fastened to the fixing hole 71. Note that the relief hole 845 is a through hole, but it may be a bottomed blind hole.

[0049] The rear lower fixing flange 83 protrudes downward from the lower end of the rear end of the cylindrical portion 81 and is substantially rectangular in shape that is long in the left - right direction when viewed from the rear. Near the lower end of the rear lower fixing flange 83, three fixing holes 831 are provided at intervals in the left - right direction. These three fixing holes 831 correspond to the positions of the three fixing holes 72 provided near the lower end of the fixing plate 7. Further, near the upper end of the rear lower fixing flange 83, four relief holes 855 are provided at intervals in the left - right direction. These four relief holes 855 correspond to the positions of the four fixing holes 71 provided near the lower edge of the opening 70 of the fixing plate 7, and are round holes with a diameter larger than that of the screw 95 fastened to the fixing hole 71. Note that the relief hole 845 is also a through - hole, but it may be a blind hole with a bottom. The rear right flange 86 protrudes rightward from the right end of the rear end of the cylindrical portion 81 and is substantially rectangular in shape when viewed from the rear. The rear left flange 87 protrudes leftward from the left end of the rear end of the cylindrical portion 81 and is substantially rectangular in shape when viewed from the rear.

[0050] The front upper fixing flange 84 protrudes upward from the upper end of the front end of the cylindrical portion 81 and is substantially rectangular in shape that is long in the left - right direction when viewed from the front. Four fixing holes 841 are provided at intervals in the left - right direction on the front upper fixing flange 84. The front lower fixing flange 85 protrudes downward from the lower end of the front end of the cylindrical portion 81 and is substantially rectangular in shape that is long in the left - right direction when viewed from the front. Four fixing holes 851 are provided at intervals in the left - right direction on the front lower fixing flange 85. The front right flange 88 protrudes rightward from the right end of the front end of the cylindrical portion 81 and is substantially rectangular in shape when viewed from the front. The front left flange 89 protrudes leftward from the left end of the rear end of the cylindrical portion 81 and is substantially rectangular in shape when viewed from the front.

[0051] Referring to FIGS. 14 to 16, an example of the assembly method of the exhaust unit 150 and the attachment method of the front cover 190 to the housing 120 will be described.

[0052] <Plate Fixing Step> The plate fixing process is a process of screwing the fixing plate 7 to the fixing flange 41 of the exhaust hood 4. As shown in FIG. 14, with the heat exchanger 6 and the exhaust hood 4 installed in the housing 120, the operator abuts the rear surface of the fixing plate 7 against the fixing flange 41 of the exhaust hood 4 via a resin packing (not shown). At this time, the position of the opening 70 of the fixing plate 7 is aligned with the exhaust port 40 of the exhaust hood 4, and the operator aligns the positions of the eight fixing holes 71 identified by the mark 75 with the positions of the four fixing holes 43 provided in the fixing flange 41 and the four fixing holes 44 provided in the lower side portion 422. At this time, when the fixing plate 7 is viewed from the front side, the upper four fixing holes 71 overlap the four fixing holes 43 of the fixing flange 41, and the lower four fixing holes 71 overlap the four fixing holes 44 of the fixing flange 41.

[0053] After alignment, the operator inserts four screws 95 from the front into the upper four fixing holes 71 identified by the mark 75 and fastens them to the four fixing holes 43 provided in the upper side portion 411. Further, four screws 95 are inserted from the front into the lower four fixing holes 71 identified by the mark 75 and fastened to the four fixing holes 44 provided in the lower side portion 412. Thereby, the fixing plate 7 is fixed to the fixing flange 41 of the exhaust hood 4.

[0054] <Adapter Fixing Process> The adapter fixing process is a process of fixing the extension adapter 8 to the fixing plate 7. As shown in FIG. 15, first, the operator abuts the rear upper fixing flange 82, the rear lower fixing flange 83, the rear right flange 86, and the rear left flange 87 of the extension adapter 8 against the front surface of the fixing plate 7 fixed to the fixing flange 41 of the exhaust hood 4 via a resin packing (not shown). At this time, on the front surface of the fixing plate 7, the rear upper fixing flange 82, the rear lower fixing flange 83, the rear right flange 86, and the rear left flange 87 are arranged inside a plurality of protruding pieces 77 provided along the outer edge of the fixing plate 7. The plurality of protruding pieces 77 contact each of the rear upper fixing flange 82, the rear lower fixing flange 83, the rear right flange 86, and the rear left flange 87 from the outside. Thereby, the rear end of the extension adapter 8 is positioned with respect to the front surface of the fixing plate 7. At this time, when the extension adapter 8 is viewed from the front side, the three fixing holes 821 overlap the three fixing holes 72 on the upper side of the fixing plate 7, and the three fixing holes 831 overlap the three fixing holes 72 on the lower side of the fixing plate 7. Further, the four relief holes 845 overlap the four screws 95 fastened to the four fixing holes 71 on the upper side of the fixing plate 7, and the four relief holes 855 overlap the four screws 95 fastened to the four fixing holes 71 on the lower side of the fixing plate 7.

[0055] With the rear end of the extension adapter 8 positioned, align the positions of the three fixing holes 821 provided in the rear upper fixing flange 82 with the positions of the three fixing holes 72 provided on the upper side of the fixing plate 7. Further, align the positions of the three fixing holes 831 provided in the rear lower fixing flange 83 with the positions of the three fixing holes 72 provided on the lower side of the fixing plate 7. Since the screws 95 are already fastened to the eight fixing holes 71 provided in the fixing plate 7, the operator can easily identify the remaining six fixing holes 72.

[0056] Here, on the front surface of the fixed plate 7, eight screws 95 are already fastened to the four upper fixing holes 71 and the four lower fixing holes 72. At the positions of each of these eight screws 95, four relief holes 845 provided in the rear upper fixing flange 82 of the extension adapter 8 and four relief holes 855 provided in the rear lower fixing flange 83 are respectively arranged. Since the relief holes 845 and 855 are larger than the diameter of the head of the screw 95, the heads of the eight screws 95 are inserted inside the corresponding relief holes 845 and 855. Thereby, the rear upper fixing flange 82 and the rear lower fixing flange 83 of the extension adapter 8 can be brought into close contact with the front surface of the fixed plate 7 without any gap.

[0057] Next, the operator inserts three screws 96 from the front into the three fixing holes 821 provided in the rear upper fixing flange 82 and fastens them to the three fixing holes 72 provided on the upper side of the fixed plate 7. Further, three screws 96 are inserted from the front into the three fixing holes 831 provided in the rear lower fixing flange 83 and fastened to the three fixing holes 72 provided on the lower side of the fixed plate 7. Thereby, the rear end portion of the extension adapter 8 is fixed to the front surface of the fixed plate 7.

[0058] <Top Fixing Step> The top fixing step is a step of fixing the exhaust top 5 to the extension adapter 8. As shown in Fig. 16, first, the operator abuts the fixing flange 52 of the exhaust top 5 against the front upper fixing flange 84, front lower fixing flange 85, front right flange 88, and front left flange 89 of the extension adapter 8 through a resin packing (not shown) from the front side. At this time, the front upper fixing flange 84, front lower fixing flange 85, front right flange 88, and front left flange 89 of the extension adapter 8 are arranged inside the protruding piece 54 provided at the outer end of the fixing flange 52. Thereby, the rear surface of the upper portion 521 of the fixing flange 52 abuts against the front surface of the front upper fixing flange 84. The rear surface of the lower portion 522 of the fixing flange 52 abuts against the front surface of the front lower fixing flange 85. At this time, when the exhaust top 5 is viewed from the front side, the four fixing holes 55 overlap with the four fixing holes 841 provided in the front upper fixing flange 84, and the four fixing holes 56 overlap with the four fixing holes 851 provided in the front lower fixing flange 85.

[0059] Then, the positions of the four fixing holes 55 provided in the upper portion 521 of the fixing flange 52 of the exhaust top 5 are aligned with the positions of the four fixing holes 841 provided in the front upper fixing flange 84. Further, the positions of the four fixing holes 56 provided in the lower portion 522 of the fixing flange 52 are aligned with the positions of the four fixing holes 851 provided in the front lower fixing flange 85.

[0060] Next, four screws 97 are inserted into the four fixing holes 55 provided in the upper portion 521 of the fixing flange 52 of the exhaust top 5 from the front and fastened to the four fixing holes 841 provided in the front upper fixing flange 84. Further, four screws 97 are inserted into the four fixing holes 56 provided in the lower portion 522 from the front and fastened to the four fixing holes 851 provided in the front lower fixing flange 85. Thereby, the fixing flange 52 of the exhaust top 5 is fixed to the front upper fixing flange 84 and front lower fixing flange 85 of the extension adapter 8 (see Figs. 10 and 11).

[0061] <Cover mounting step> The cover attachment step is a step of screwing the front cover 190 to the front surface of the housing 120 that opens. When fixing the front cover 190 to the front surface of the housing 120 that opens with screws (not shown), the front end side of the cylindrical portion 51 of the exhaust top 5 is inserted from the rear into the inside of the insertion port 191 provided in the front cover 190. As shown in FIGS. 7 and 8, in a state where the front cover 190 is fixed to the front surface of the housing 120, the front end portion of the cylindrical portion 51 of the exhaust top 5 protrudes forward from the insertion port 191 of the front cover 190.

[0062] In the exhaust unit 150 of such a water heater 100, the combustion exhaust gas that has flowed into the inside of the exhaust hood 4 is guided forward by the rectifying plate 46, and flows into the inside of the cylindrical portion 81 of the extension adapter 8 through the opening 70 of the fixing plate 7 from the exhaust port 40. Further, the combustion exhaust gas flows into the cylindrical portion 51 of the exhaust top 5 from the cylindrical portion 81, and by flowing forward in the cylindrical portion 51, it is discharged to the outside of the housing 120.

[0063] As described above, the water heater 1 of the present embodiment includes a heat exchanger 3 having a heat transfer pipe 35 that heats the flowing water with combustion exhaust gas from a burner, an exhaust hood 4 that discharges the combustion exhaust gas that has passed through the heat exchanger 3 to the outside, a housing 2 whose front surface is open and that mounts the heat exchanger 3 and the exhaust hood inside, and a front cover 9 that is attached to the front surface of the housing 2 that opens. An insertion port 91 is provided in the front cover 9 at a position corresponding to the exhaust port 40 that opens in front of the exhaust hood 4. When assembling the water heater 100, which is a similar model to the water heater 1, the housing 2 is changed to a housing 120 that is longer in the front-rear width than the housing 2. In this case, a front cover 190 is attached to the front surface of the housing 120 that opens. And the distance from the exhaust port 40 of the exhaust hood 4 to the insertion port 191 of the front cover 190 becomes longer than the distance from the exhaust port 40 to the insertion port 91 of the front cover 9 in the water heater 1.

[0064] In such a water heater 1, 100, when assembling the water heater 1 in the housing 2, in the top fixing step, the cylindrical exhaust top 5 is positioned with respect to the fixing flange 41 of the exhaust hood 4, and the positions of the plurality of fixing holes 55, 56 provided in the exhaust top 5 are aligned with the positions of the plurality of fixing holes 43, 44 provided in the fixing flange 41 and screwed. Next, in the cover attachment step, with the exhaust top 5 screwed to the fixing flange 41 in the top fixing step, the front cover 9 is attached to the front surface of the housing 2 where the opening is located, and the front end portion of the exhaust top 5 is inserted into the insertion port 91 of the front cover 9 from the rear.

[0065] On the other hand, when assembling the water heater 100 in the housing 120, the fixing plate 7 and the extension adapter 8 are prepared. The fixing plate 7 has an opening 70 in a portion facing the exhaust port 40 of the exhaust hood 4. The fixing plate 7 is provided with a plurality of fixing holes 71, a plurality of fixing holes 72, and a plurality of marks 75. The plurality of fixing holes 71 correspond to the plurality of fixing holes 43, 44 provided in the fixing flange 41 of the exhaust hood 4 respectively. The plurality of fixing holes 72 are provided at positions different from the plurality of fixing holes 71. The plurality of marks 75 are marks for discriminating the plurality of fixing holes 71 with respect to the plurality of fixing holes 72. The extension adapter 8 is cylindrical and extends in the front-rear direction. The extension adapter 8 is provided with a plurality of fixing holes 821, 831 and a plurality of fixing holes 841, 851. The plurality of fixing holes 821, 831 correspond to the plurality of fixing holes 72 provided in the fixing plate 7 respectively. The plurality of fixing holes 841, 851 correspond to the plurality of fixing holes 55, 56 provided in the exhaust top 5 respectively.

[0066] First, in the plate fixing step, the fixing plate 7 is positioned with respect to the fixing flange 41 of the exhaust hood 4, and the positions of the plurality of fixing holes 71 discriminated by the mark 75 of the fixing plate 7 are aligned with the positions of the plurality of fixing holes 43, 44 provided in the fixing flange 41, and the screw 95 is tightened. Next, in the adapter fixing step, the extension adapter 8 is positioned on the fixing plate 7, and the positions of the plurality of fixing holes 821, 831 provided in the extension adapter 8 are aligned with the positions of the plurality of fixing holes 72 provided in the fixing plate 7, and the screw 96 is tightened.

[0067] Next, in the top fixing step, the exhaust top 5 is positioned with respect to the extension adapter 8, and the screws 97 are fastened by aligning the positions of the plurality of fixing holes 55, 56 provided in the exhaust top 5 with the positions of the plurality of fixing holes 841, 851 provided in the extension adapter 8. Finally, in the cover attachment step, the extension adapter 8 is screwed to the fixing plate 7, and with the exhaust top 5 screwed to the extension adapter 8, the front cover 190 is attached to the front surface of the housing 120 where the opening is located, and the front end portion of the cylindrical portion 51 of the exhaust top 5 is inserted into the insertion port 191 from the rear.

[0068] In this way, in the plate fixing step, the operator can identify the plurality of fixing holes 71 without misidentifying them as the plurality of fixing holes 72 by checking the mark 75 provided on the front surface of the fixing plate 7. As a result, the operator can correctly fix the fixing plate 7 to the fixing flange 41 of the exhaust hood 4. Also, after screwing the fixing holes 71 of the fixing plate 7, by checking the mark 75, it is possible to easily visually determine whether the fixing holes 71 are correctly screwed or not mistakenly screwed to the fixing holes 72.

[0069] Further, on the front surface 74 of the fixing plate 7, since the mark 75 is provided adjacent to the fixing holes 71, the fixing holes 71 can be easily distinguished from the other fixing holes 72.

[0070] Also, since the mark 75 is engraved on the front surface 74 of the fixing plate 7, it is possible to prevent the mark 75 from disappearing from the front surface 74. Also, since the mark 75 can be formed without increasing the number of steps of the press for manufacturing the fixing plate 7, it can be implemented at low cost.

[0071] In the above description, the housing 2 of the water heater 1 is an example of the "first housing" of the present invention. The front cover 9 is an example of the "first cover" of the present invention, and the insertion port 91 provided on the front cover 9 is an example of the "first insertion port" of the present invention. The housing 120 of the water heater 100 is an example of the "second housing" of the present invention. The front cover 190 is an example of the "second cover" of the present invention, and the insertion port 191 provided on the front cover 190 is an example of the "second insertion port" of the present invention. The exhaust hood 4 is an example of the "exhaust part" of the present invention. The fixing flange 41 of the exhaust hood 4 is an example of the "peripheral part of the exhaust port 40" of the present invention.

[0072] The fixing holes 43, 44 provided on the fixing flange 41 are an example of the "first fixing holes" of the present invention. The fixing holes 55, 56 provided on the exhaust top 5 are an example of the "second fixing holes" of the present invention. The fixing hole 71 provided on the fixing plate 7 is an example of the "third fixing hole" of the present invention, and the fixing hole 72 is an example of the "fourth fixing hole" of the present invention. The fixing holes 821, 831 provided on the extension adapter 8 are an example of the "fifth fixing holes" of the present invention, and the fixing holes 841, 851 are an example of the "sixth fixing holes" of the present invention.

[0073] The top fixing process of the water heater 1 is an example of the "first process" of the present invention, and the cover mounting process is an example of the "second process" of the present invention. The plate fixing process of the water heater 100 is an example of the "third process" of the present invention, the adapter fixing process is an example of the "fourth process" of the present invention, the top fixing process is an example of the "fifth process" of the present invention, and the cover mounting process is an example of the "sixth process" of the present invention.

[0074] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible. The above-described embodiments are the water heaters 1 and 100, but the present invention is also applicable to other hot water devices such as water heaters. The piping configuration inside the water heaters 1 and 100 is not limited to the above-described embodiments. Also, the arrangement and shape of the heat transfer tubes 35 of the heat exchanger 3 and the arrangement and shape of the heat transfer tubes 65 of the heat exchanger 6 can be freely changed.

[0075] In the above-described embodiment, the heat exchanger 6 of the water heater 100 is larger in size than the heat exchanger 3 of the water heater 1, but they may have the same size. The heat exchangers may be the same component. The present invention is applicable to at least two similar models of a hot water device housing having different front-to-back widths.

[0076] In the above-described embodiment, when assembling the water heater 100 in the housing 120, after the plate fixing step, the adapter fixing step is performed and then the top fixing step is performed. However, the adapter fixing step may be performed after the top fixing step. That is, in the above-described embodiment, the extension adapter 8 is screwed to the fixing plate 7 and then the exhaust top 5 is screwed to the extension adapter 8. However, the exhaust top 5 may be screwed to the extension adapter 8 first, and then the extension adapter 8 may be screwed to the fixing plate 7.

[0077] In the above-described embodiment, on the front surface 74 of the fixing plate 7, the mark 75 is engraved directly above the fixing hole 71, but it may be at a position close to the fixing hole 71. Also, the position where the mark 75 is engraved may not be in the vicinity of the fixing hole 71 but in the vicinity of the fixing hole 72. Also, the shape of the mark 75 is not limited to "▽", and for example, it may be an arrow indicating the fixing hole 71. Also, marks of different shapes may be engraved in the vicinity of each of the fixing hole 71 and the fixing hole 72. For example, the screwing order may be engraved. Also, the mark 75 is engraved on the front surface 74 of the fixing plate 7, but other forming methods may also be used, for example, printing or pasting a sticker.

Explanation of Reference Numerals

[0078] 1 Water heater 2 Housing 3 Heat exchanger 4 Exhaust hood 5 Exhaust top 6 Heat exchanger 7 Fixing plate 8 Extension adapter 9 Front cover 15 Exhaust unit 35 Heat transfer tube 41 Fixing flange 43, 44 Fixing holes 55, 56 fixing holes 65 heat transfer tube 70 opening 71, 72 fixing holes 74 front surface 75 mark 91 insertion port 94 - 97 screws 100 water heater 120 housing 150 exhaust unit 190 front cover 191 insertion port 821, 831 fixing holes 841, 851 fixing holes 845, 855 relief holes

Claims

1. A water heater comprising a heat exchanger having a heat transfer tube for heating water flow with combustion exhaust from a burner, an exhaust section for discharging the combustion exhaust that has passed through the heat exchanger to the outside, a first housing having an opening at the front and having the heat exchanger and the exhaust section attached inside, and a first cover attached to the front surface of the first housing that opens, wherein a first insertion port is provided in the first cover at a position corresponding to an exhaust port that opens in front of the exhaust section. When changing from the first housing to a second housing having a longer front-rear width than the first housing, a second cover is attached to the front surface of the second housing that opens, and the distance from the exhaust port to a second insertion port provided at a position corresponding to the exhaust port of the second cover is longer than the distance from the exhaust port to the first insertion port. A method for assembling the water heater, comprising: When assembling the water heater with the first housing, A first step of positioning an exhaust top provided in a cylindrical shape with respect to a peripheral portion of the exhaust port of the exhaust section, and screwing the exhaust top by aligning the position of a second fixing hole provided in the exhaust top with the position of a first fixing hole provided in the peripheral portion; A second step of attaching the first cover to the front surface of the first housing that opens in a state where the exhaust top is screwed to the peripheral portion in the first step, and inserting a front end portion of the exhaust top into the first insertion port from behind; Comprising; When assembling the water heater with the second housing, Preparing a fixing plate having an opening at a portion corresponding to the exhaust port, a third fixing hole corresponding to the first fixing hole, a fourth fixing hole at a position different from the third fixing hole, and a mark for discriminating between the third fixing hole and the fourth fixing hole, and a cylindrical extension adapter extending in the front-rear direction and having a fifth fixing hole corresponding to the fourth fixing hole and a sixth fixing hole corresponding to the second fixing hole; A third step of positioning the fixing plate with respect to the peripheral portion of the exhaust port, and screwing the fixing plate by aligning the position of the third fixing hole provided in the fixing plate and discriminated by the mark with the position of the first fixing hole provided in the peripheral portion; A fourth step of positioning the extension adapter with respect to the fixing plate, and screwing the extension adapter by aligning the position of the fifth fixing hole provided in the extension adapter with the position of the fourth fixing hole provided in the fixing plate; A fifth step of positioning the exhaust top with respect to the extension adapter and screwing the exhaust top with the position of the second fixing hole provided in the exhaust top aligned with the position of the sixth fixing hole provided in the extension adapter; A sixth step of attaching the second cover to the front surface of the second housing that opens in a state where the extension adapter is screwed to the fixing plate in the fourth step and the exhaust top is screwed to the extension adapter in the fifth step, and inserting the front end portion of the exhaust top into the second insertion port from the rear; Comprising An assembling method of a hot water device, characterized in that.

2. The mark is provided adjacent to the third fixing hole The assembling method of the hot water device according to claim 1, characterized in that.

3. The mark is engraved on the front surface of the fixing plate The assembling method of the hot water device according to claim 1 or 2, characterized in that.

4. An exhaust unit including an exhaust port for discharging the combustion exhaust that has passed through a heat exchanger that heats the flowing water with the combustion exhaust from a burner to the outside, and a cylindrical exhaust top that is directly or indirectly fixed to the peripheral edge of the exhaust unit, a first housing having an open front surface and attaching the heat exchanger and the exhaust unit inside, and a first cover attached to the front surface of the first housing that opens and having a first insertion port into which the front end portion of the exhaust top is inserted from the rear at a position opposite to the exhaust port of the exhaust unit, or a second housing that is longer in the front-rear width than the first housing from the first housing, and a second cover attached to the front surface of the second housing that opens, and the distance from the exhaust port to the second insertion port provided at a position opposite to the exhaust port of the second cover is longer than the distance from the exhaust port to the first insertion port, which is a hot water device exhaust unit provided in any of the second hot water devices, When provided in the first hot water device, While the second fixing hole provided in the exhaust top is positioned with respect to the first fixing hole provided in the peripheral edge of the exhaust unit and the exhaust top is screwed to the peripheral edge, When provided in the second hot water device, it further includes a fixing plate and an extension adapter interposed between the exhaust unit and the exhaust top, The fixing plate has an opening in a portion opposite to the exhaust port, and the extension adapter has a cylindrical shape extending in the front-rear direction, The fixed plate is provided with a third fixing hole corresponding to the first fixing hole, a fourth fixing hole at a position different from the third fixing hole, and a mark for discriminating between the third fixing hole and the fourth fixing hole. The extension adapter is provided with a fifth fixing hole corresponding to the fourth fixing hole and a sixth fixing hole corresponding to the second fixing hole. With respect to the first fixing hole provided at the peripheral portion of the exhaust port, the third fixing hole provided in the fixed plate and discriminated by the mark is positioned, and the fixed plate is screwed to the peripheral portion. With respect to the fourth fixing hole provided in the fixed plate, the fifth fixing hole provided in the extension adapter is positioned, and the extension adapter is screwed to the fixed plate. With respect to the position of the sixth fixing hole provided in the extension adapter, the second fixing hole provided in the exhaust top is positioned, and the exhaust top is screwed to the extension adapter. With the extension adapter screwed to the fixed plate and the exhaust top screwed to the extension adapter, the second cover is attached to the front surface of the second housing that opens, and the front end portion of the exhaust top is inserted into the second insertion port from the rear. An exhaust unit for a hot water device, characterized in that.

5. The extension adapter includes a plate-shaped fixed portion that abuts against and is fixed to the fixed plate. The fixed portion is the fifth fixing hole, a relief hole provided at a position corresponding to the third fixing hole of the fixed plate to avoid interference with the head of the screw fastened to the third fixing hole and is provided with. An exhaust unit for a hot water device according to claim 4, characterized in that.

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