JP7080440B2 - Hot water device - Google Patents

Description

The present invention relates to a hot water device such as a hot water supply device configured by combining a combustion device and a heat exchanger.

As a hot water device, a combination of a combustion device and a heat exchanger is widely known. The combustion device is, for example, a plurality of burners, a burner case for accommodating the plurality of burners side by side, a fan for supplying combustion air from below the burner case, and a fuel for supplying fuel gas to the plurality of burners. It is configured to be equipped with a gas supply head and the like. On the other hand, the heat exchanger is arranged above the plurality of burners and is provided with a heat transfer tube through which hot water to be heated flows. As the heat transfer tube, for example, a plurality of straight tube portions extending in a substantially horizontal direction intersecting the side-by-side arrangement direction of the plurality of burners are arranged in the side-by-side arrangement direction, and then a series of them via the connecting tube body portion. (See, for example, Patent Documents 1 to 3).

On the other hand, as a manufacturer of a water heater, it is required to manufacture and prepare a plurality of types of water heaters having different uses or hot water supply capacities to meet the needs of customers. For example, a hot water device used for general hot water supply and hot water heating may be required separately from the hot water device used for general hot water supply and bath hot water supply (bath reheating). It is necessary that the maximum combustion thermal power of the combustion device is larger for hot water heating applications than for bath hot water supply applications. In such a case, if the specifications of the combustion device and the heat exchanger constituting the water heater are different each time the hot water supply application or the hot water supply capacity is different, there is a problem that the manufacturing cost of these is high.
Therefore, in the past, for example, a part of the plurality of burners provided in the combustion device was changed to a non-combustion burner, or the total number of the plurality of burners was changed to significantly change the overall specifications of the water heater. There is a means for changing the combustion thermal power of the combustion device and adjusting the hot water supply capacity without doing so (Patent Documents 1 and 2).

However, when the above-mentioned means is adopted, the following problems may occur.

That is, when a part of the plurality of burners is a non-combustion burner, the combustion gas is efficiently used in the straight tube portion located above the non-combustion burner among the plurality of straight tube portions of the heat transfer tube. Combustion air with a low temperature will act. Therefore, hot water circulating in the heat transfer tube and heated by a plurality of burners passes above the non-combustion burner in the middle of the distribution process or at the end of the distribution process, and is cooled by the combustion air. There is a risk that it will be done. In this case, the heat loss is large and the thermal efficiency is low.
Such a defect also occurs when the total number of the plurality of burners is reduced and the region where the burners are not provided is provided below the heat transfer tube.

Japanese Unexamined Patent Publication No. 2013-29256 Japanese Unexamined Patent Publication No. 2013-11409 Japanese Unexamined Patent Publication No. 2008-76002 Japanese Patent No. 4015775

The present invention has been conceived under the above-mentioned circumstances, and provides a hot water device capable of improving the thermal efficiency while making it possible to change the hot water generation capacity easily and at low cost. The challenge is to provide it.

In order to solve the above problems, the following technical means are taken in the present invention.

The water heating device provided by the first aspect of the present invention includes a fuel device and a heat exchanger, and the fuel device includes a burner case for accommodating a plurality of burners side by side and the burner case. A fan capable of supplying combustion air from the lower side thereof and a fuel gas supply head capable of supplying fuel gas to the plurality of burners are provided inside, and the heat exchanger is above the plurality of burners. It is equipped with a heat transfer tube that is located in and through which hot water supplied from the water inlet flows, and this heat transfer tube is a plurality of straight tubes extending in a substantially horizontal direction intersecting the side-by-side direction of the plurality of burners. A water heating device having a portion and having a configuration in which these plurality of straight tube portions are arranged side by side and connected in a series, wherein the heat exchanger is the plurality of direct pipe portions. Among the tubular parts, the straight pipe portion located at one end in the side-by-side arrangement direction is the water inlet side straight pipe portion closest to the water inlet, and a part of the plurality of burners is the above. Since the fuel gas supply from the fuel gas supply head is constantly stopped, it is a non-combustion burner that does not cause drive combustion, and the water inlet side straight tube body is located above this non-combustion burner. It is characterized by being.

With such a configuration, the following effects can be obtained.
First, in the above configuration, if the fuel gas is supplied from the fuel gas supply head to the non-combustion burner, the non-combustion burner can be driven and burned in the same manner as other burners, whereby the combustion device can be driven and burned. It is possible to increase the combustion thermal power. Therefore, it is possible to easily and appropriately increase the hot water generation capacity at low cost without significantly changing the specifications of each part of the hot water device, and it is possible to reduce the manufacturing cost of the hot water device. can. For example, when the hot water device according to the present invention is used for bath hot water supply, the specifications can be easily changed as a hot water device for hot water heating by designating a non-combustion burner to be driven and burned in the same manner as other burners. It becomes possible to do.
Secondly, according to the present invention, the hot water flowing into the heat transfer tube from the water inlet is located above the non-combustion burner among the plurality of straight pipes, so that the water inlet side on which the combustion air acts. It first passes through the straight tube body. The hot water is subsequently heated by the combustion gas in the process of passing through the other straight tube body portion. Therefore, it is appropriately avoided that the hot water after being heated by the combustion gas passes above the non-combustion burner and is cooled by the low-temperature combustion air, and does not cause a large heat loss due to the combustion air. Can be done. As a result, the thermal efficiency can be improved and the energy saving performance can be improved.
Thirdly, if low-temperature hot water enters the heat transfer tube, dew condensation may occur on the heat transfer tube. The more it works, the more it becomes. On the other hand, according to the present invention, a large amount of combustion gas does not act on the water inlet side straight pipe body portion having the lowest hot water temperature inside among the plurality of straight pipe body portions. Therefore, it is possible to reduce the amount of dew condensation water generated in the heat exchanger and appropriately prevent or suppress the progress of corrosion of the heat transfer tube due to the dew condensation water and the occurrence of exhaust blockage.

In the present invention, preferably, the plurality of burners including the non-combustion burner have a gas inlet and an upward-opening flame hole surface, and the plurality of burners other than the non-combustion burner are the gas. A mixed gas of combustion air and fuel gas introduced inside from the introduction port is made combustible at the flame hole surface, and in the non-combustion burner, the combustion air introduced inside from the gas introduction port is the flame. It is configured to flow upward from the hole surface.

According to such a configuration, the action of the combustion air flowing upward from the flame hole surface of the non-combustion burner stabilizes the drive combustion state (flame generation state, etc.) of other burners adjacent to this non-combustion burner. The effect of making it is obtained. More specifically, there is another burner on both the left and right sides of one burner, and the combustion air is flowing upward, whereas there is no burner on the other, and the one is for combustion. If the air flow is different, the flame becomes unstable, but according to the above configuration, such a phenomenon can be appropriately prevented or suppressed.

In the present invention, preferably, the non-combustion burner has a form extending in the longitudinal direction of the water inlet side straight tube portion, and the gas introduction port is provided at one end portion in the longitudinal direction. At the same time, a gas flow path is formed inside, in which the combustion air flowing into the gas introduction port is advanced to the other end side in the longitudinal direction and then upward to be guided to the flame hole surface. In the water inlet side straight tube body portion, the hot water flowing in from the water inlet is configured to flow in the direction from the other end side of the non-combustion burner toward the one end side.

With such a configuration, the following effects can be obtained.
In the non-combustion burner described above, the combustion air flowing into the internal gas flow path from the gas introduction port travels toward the other end of the non-combustion burner and then travels upward. Since the air flows out from the flame hole surface above it, the amount of this air outflow is larger on the other end side than on the one end side of the non-combustion burner. On the other hand, the hot water flowing through the straight pipe portion on the water inlet side passes through the above-mentioned region where the amount of air outflow is large, and then heads for the region where the amount of air outflow is small. Therefore, it is possible to further reduce the heat loss due to the hot water flowing through the water inlet side straight tube body being cooled by the combustion air, and further improve the thermal efficiency.

The water heating device provided by the second aspect of the present invention includes a combustion device and a heat exchanger, and the combustion device includes a burner case for accommodating a plurality of burners side by side and the burner case. A fan capable of supplying combustion air from the lower side thereof and a fuel gas supply head capable of supplying fuel gas to the plurality of burners are provided inside, and the heat exchanger is above the plurality of burners. The heat transfer tube is located in the water and is provided with a heat transfer tube through which hot water supplied from the water inlet flows, and the heat transfer tube is a plurality of straight tubes extending in a substantially horizontal direction intersecting the side-by-side direction of the plurality of burners. A water heating device having a portion and having a configuration in which these plurality of straight pipe portions are arranged side by side and connected in a series, wherein the heat exchanger is the plurality of direct pipe portions. Among the tubular portions, the straight tubular portion located at one end in the side-by-side arrangement direction is the water inlet-side straight tubular portion closest to the water inlet, and the burner case contains the plurality of. A free area for installing a burner is provided in which another burner having the same configuration as each of the burners can be additionally installed without arranging any of the burners, and the above-mentioned input is provided above the free area for installing the burner. It is characterized by the location of the water-side straight tube body.

The configuration corresponds to the configuration in which the non-combustion burner is removed in the hot water apparatus provided by the first aspect of the present invention, and the following effects can be obtained.
First, if a burner is installed in an empty area for installing a burner and the burner is supplied with fuel gas from a fuel gas supply head, this burner can be driven and burned in the same manner as other burners. Therefore, it is possible to easily and appropriately increase the hot water generation capacity at low cost without significantly changing the specifications of each part of the hot water device.
Secondly, the hot water that has flowed into the heat transfer tube from the water inlet is located above the empty area for installing the burner among the multiple straight pipes, and the combustion air acts on the straight pipe on the water inlet side. First passes through, and then passes through another straight tube body to be heated. Therefore, it is possible to appropriately prevent the hot water after being heated by the combustion gas from being cooled by the low-temperature combustion air, and to improve the thermal efficiency.
Thirdly, among the plurality of straight pipes, dew condensation can be suppressed because a large amount of combustion gas can be prevented from acting on the water inlet side straight pipes having the lowest hot water temperature inside. It is also possible to appropriately prevent or suppress the progress of corrosion of the heat transfer tube due to dew condensation water and the occurrence of exhaust blockage.
As described above, the same effect as that of the hot water apparatus provided by the first aspect of the present invention can be obtained in the hot water apparatus provided by the second aspect of the present invention.

Other features and advantages of the invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.

It is a schematic front sectional view which shows an example of the hot water apparatus which concerns on this invention. (A) is a cross-sectional view taken along the line IIa-IIa of FIG. 1, and FIG. 1 (b) is a cross-sectional view taken along the line IIb-IIb of FIG. FIG. 3 is a plan sectional view of a main part showing a primary heat exchanger of the hot water apparatus shown in FIG. 1. It is a schematic front sectional view which shows the other example of the hot water apparatus which concerns on this invention.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

The water heater WH shown in FIGS. 1 and 2 is configured as a hot water supply device, and includes a combustion device C and a heat exchanger HE. This water heater WH can independently perform two systems of hot water supply operation, for example, general hot water supply and bath hot water supply (bath reheating), and is a so-called one-can two-circuit system.

The combustion device C includes a plurality of first and second burners 1A and 1B, a burner case 2 for accommodating them side by side, a fan 3 with a motor M, and a fuel gas supply head 4.

Each of the first and second burners 1A and 1B is a so-called gas combustion pipe having a flat shape as a whole, a gas introduction port 11 is provided on one end side thereof, and a flame hole surface 12 is provided on the upper surface portion. Is the formed configuration. By flowing a mixed gas of fuel gas and combustion air into the gas introduction port 11, it is possible to burn the fuel gas at the flame hole surface 12. A partition member 90 is provided in the burner case 2, and a first combustion chamber Ra in which a plurality of first burners 1A are arranged and a second combustion chamber in which a plurality of second burners 1B are arranged are arranged. It is partitioned into a chamber Rb. The first burner 1A is for heating hot water during general hot water supply. On the other hand, the second burner 1B is for heating hot water at the time of hot water supply to the bath, and the total number is smaller than that of the first burner 1A. In the drawings, reference numerals 92a to 92c are heat shield plates for preventing thermal damage to the burner case 2 or the partition member 90 and for positioning the first and second burners 1A and 1B.
Of the plurality of second burners 1B, the burner located at the left end of FIG. 1 is a non-combustion burner 1B'in which drive combustion is constantly stopped, as will be described later. The configuration of the non-combustion burner 1B'itself is the same as the configuration of the other second burner 1B.

The fuel gas supply head 4 is attached to the front side of the burner case 2 and can supply fuel gas to each of the first and second burners 1A and 1B except for the non-combustion burner 1B'. Specifically, as shown in FIG. 2A, the fuel gas supply head 4 includes a fuel gas ejection nozzle 40 facing the gas introduction port 11 of the second burner 1B, such as a supply head gas pipe. The fuel gas supplied to the fuel gas supply head 4 via the fuel gas supply head 4 can be ejected toward the gas introduction port 11. Similarly, fuel gas can be ejected from the gas inlet 11 of the first burner 1A.

However, as shown in FIG. 2B, the fuel gas ejection nozzle 40 is not provided at the portion of the non-combustion burner 1B' facing the gas introduction port 11, but the fuel ejection nozzle base portion 41 is provided. ing. The fuel ejection nozzle base portion 41 is a portion where the nozzle is not in an open state and the fuel gas is not ejected to the non-combustion burner 1B'. The fuel gas ejection nozzle 40 shown in FIG. 2A is a portion that communicates with the gas supply path in the fuel gas supply head 4 due to the nozzle opening processing, which is shown in FIG. 2B. The fuel ejection nozzle base portion 41 shown is a portion where the nozzle opening is not processed.

A straightening vane 29 having a plurality of ventilation holes 29a is provided at the bottom of the burner case 2, and an air flow path 28 is formed below the straightening vane 29. A part of the combustion air discharged from the fan 3 passes upward through the ventilation holes 29a and proceeds to the installation areas of the first and second burners 1A and 1B, and the other part of the combustion air. Passes through the air flow path 28, travels between the fuel gas supply head 4 and the lower front surface of the burner case 2, and flows into the gas inlets 11 of the first and second burners 1A and 1B. Has been done.

As described above, the fuel gas does not flow into the gas inlet 11 of the non-combustion burner 1B', but the combustion air does flow in, and the combustion air passes through the internal flow path 13 and has a flame hole. It flows upward from the surface 12. The flow path 13 is formed so that the combustion air flowing into the gas introduction port 11 is advanced from the one end 14a side to the other end 14b side of the non-combustion burner 1B'and then upward. Therefore, the amount of outflow of combustion air from the flame hole surface 12 upward is larger on the other end 14b side of the non-combustion burner 1B' than on the one end 14a side.

The heat exchanger HE has a configuration in which the first and second heat transfer tubes 6A and 6B for heating hot water are housed in the can body 5 mounted on the burner case 2. The first and second heat transfer tubes 6A and 6B are configured as finned tubes having a plurality of fins 68a and 68b, and these are partitioned by a partition member 91. The first heat transfer tube 6A is for general hot water supply, and the second heat transfer tube 6B is for bath hot water supply.

As shown in FIG. 3, in the second heat transfer tube 6B, a plurality of straight tube body portions 60 extending in the front-rear direction of the water heating device WH are arranged at intervals in the lateral width direction of the water heating device WH, and a connecting tube is provided. It has a structure connected in a series via a body portion 61, and its overall shape is, for example, a meandering shape in a plan view, and is single-stage in the vertical height direction. However, it can be provided in multiple stages. Of the plurality of straight tube bodies 60, the straight tube body 60 located at one end (closer to the side wall 5a of the can body 5) on the opposite side of the first heat transfer tube 6A enters the one end. The auxiliary pipe body 62 having the water port 62a is connected to the water inlet 62a, and the water inlet side straight pipe body portion 60a (60) is the closest to the water inlet 62a. As shown in FIG. 1, the second heat transfer tube 6B is located above the plurality of second burners 1B, but the non-combustion burner 1B'is located below the water inlet side straight tube body portion 60a. positioned. Further, the auxiliary pipe body 62 is provided on the back side of the water heating device WH, and the hot water flowing from the auxiliary pipe body 62 into the water inlet side straight pipe body portion 60a flows into the water inlet side straight pipe body portion 60a. It is configured to flow from the back side to the front side of the hot water device WH (from the other end 14b side of the non-combustion burner 1B'to the one end 14a side).

The first heat transfer tube 6A is located above the first combustion chamber Ra, and the hot water flowing into the first heat transfer tube 6A from the water inlet advances upward from the first combustion chamber Ra. It is configured to be heated by the coming combustion gas. Although the detailed configuration of the first heat transfer tube 6A will be omitted, the first heat transfer tube 6A may be appropriately provided with a plurality of straight tube bodies similar to the straight tube body 60 described above. It is connected in a series via a connecting pipe body, and is provided in multiple stages above and below or in a single stage.
An exhaust collecting cylinder is provided on the upper side of the heat exchanger HE to discharge the combustion gas that has passed through the heat exchanger HE to the outside as exhaust gas, or further latent heat is recovered from the combustion gas that has passed through the heat exchanger HE. Another heat exchanger (heat exchanger for latent heat recovery) is appropriately provided.

Next, the operation of the above-mentioned hot water device WH will be described.

First, when hot water is supplied to the bath, it is possible to heat the hot water by driving and burning a plurality of second burners 1B excluding the non-combustion burner 1B'. Here, there is a case where it is desired to increase the maximum combustion thermal power of the plurality of second burners 1B and make the specifications of the hot water device WH suitable for hot water heating and hot water supply. In this case, a nozzle opening may be formed in the fuel ejection nozzle base portion 41 of the fuel gas supply head 4 shown in FIG. 2 (b) so that the fuel gas can be supplied to the non-combustion burner 1B'. As a result, the non-combustion burner 1B'can be driven and burned in the same manner as the other second burner 1B, and the hot water generation capacity is increased and hot water heating is performed without significantly changing the specifications of each part of the water heater WH. It can be suitable for hot water supply. This is advantageous in reducing the manufacturing cost of the hot water device having the bath hot water supply function and the hot water device having the heating hot water supply function in common.

When the second burner 1B excluding the non-combustion burner 1B'is driven and burned to heat the hot water in order to supply hot water to the bath, the hot water flowing into the second heat transfer tube 6B from the water inlet 62a is non-combustion. After passing through the water inlet side straight tube body portion 60a located above the burner 1B', the other straight tube body portions 60 are sequentially circulated, and the heat is efficiently heated in this process. Combustion gas does not act so much on the water inlet side straight tube body portion 60a, and the combustion air flowing out from the flame hole surface 12 of the non-combustion burner 1B'and the combustion that has passed through the peripheral portion of the non-combustion burner 1B' The hot water flowing through the water inlet side straight tube body portion 60a is in a state where it has not been heated by the second burner 1B, or is in a state where it is hardly heated. Therefore, the heat loss due to the action of the combustion air on the water inlet side straight pipe body portion 60a is small. Further, the hot water after being heated to a high temperature by the second burner 1B is not cooled by the combustion air, so that a large amount of heat loss does not occur. Therefore, it is possible to prevent the problem that the thermal efficiency is lowered due to the provision of the non-combustion burner 1B'and to make the thermal efficiency excellent.

As described with reference to FIG. 2B, the amount of outflow of combustion air from the flame hole surface 12 of the non-combustion burner 1B'is one end on the other end 14b side of the non-combustion burner 1B'. It will be more than the 14a side. On the other hand, in the water inlet side straight pipe body portion 60a, hot water is configured to flow in the direction from the other end portion 14b side of the non-combustion burner 1B'to the one end portion 14a side, and is configured to flow toward the one end portion 14a side. The temperature gradually rises as it flows. Therefore, in the process of flowing hot water through the water inlet side straight pipe body portion 60a, it is possible to suppress the action of cooling the hot water having a temperature rise by the combustion air, and it is possible to further improve the thermal efficiency. Is.

If relatively low-temperature hot water enters the second heat transfer tube 6B from the water inlet 62a and the combustion gas acts on the second heat transfer tube 6B, dew condensation may occur on the second heat transfer tube 6B. The amount of dew condensation water generated increases as more combustion gas acts on the low temperature portion of the second heat transfer tube 6B. On the other hand, in the water heating device WH of the present embodiment, a large amount of combustion gas does not act on the water inlet side straight pipe body portion 60a where the internal hot water temperature is the lowest among the plurality of straight pipe body portions 60. .. Therefore, the amount of dew condensation water generated should be reduced, the progress of corrosion of the second heat transfer tube 6B and fin 68b caused by the dew condensation water should be prevented, and the occurrence of exhaust blockage in the heat exchanger HE should be appropriately prevented. Is possible.

The non-combustion burner 1B'also serves to stabilize the drive combustion of the second burner 1B adjacent thereto (indicated by reference numeral 1B "in FIG. 1 and hereinafter referred to as the adjacent burner 1B"). That is, if the non-combustion burner 1B'is not provided, the other second burner 1B is present on one side of the adjacent burner 1B ", whereas the other side is merely a space. For this reason, the flow of combustion air differs between the left and right sides of the adjacent burner 1B ", and there is a risk that the drive combustion of the adjacent burner 1B" will be unstable (flame is asymmetrical to the left and right). On the other hand, if the non-combustion burner 1B'is provided, there is an advantage that the flow of combustion air on both the left and right sides of the adjacent burner 1B "is made uniform and the drive combustion of the adjacent burner 1B" is stabilized.

FIG. 4 shows another embodiment of the present invention. In the figure, the same or similar elements as those in the embodiment are designated by the same reference numerals as those in the embodiment, and duplicate description will be omitted.

The hot water device WHa shown in FIG. 4 corresponds to a configuration in which the non-combustion burner 1B'is removed from the hot water device WH of the above embodiment, and the other configurations are the same as those of the hot water device WH. In the water heating device WHa of the present embodiment, as a result of not providing the non-combustion burner 1B', the lower region of the water inlet side straight tube body portion 60a of the second heat transfer tube 6B in the burner case 2 is the second. The burner 1B of 2 is not provided, and it is a free area AR for burner installation in which a burner having the same configuration as that of the second burner 1B can be additionally installed.

According to the present embodiment, although the above-mentioned effect of stabilizing the drive combustion of the adjacent burner 1B "by using the non-combustion burner 1B'cannot be obtained, the second burner 1B is used in the free area AR for burner installation. By installing a burner having the same configuration and making it possible to supply fuel gas to this burner, it is possible to easily and at low cost to increase the hot water generation capacity. Further, in the present embodiment, the burner is installed. The combustion air supplied to the free space AR will act on the water inlet side straight tube body portion 60a, but this does not cause much heat loss and is heated by the second burner 1B. The subsequent hot water is not cooled by the combustion air and causes a large amount of heat loss. Therefore, it is possible to improve the thermal efficiency as in the above embodiment. In addition, there is an advantage that dew condensation can be prevented from occurring.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each part of the water heating device according to the present invention can be variously redesigned within the scope of the present invention.

In the above-described embodiment, a so-called one-can two-circuit system is used as a specific example, and a part of the second burner 1B of the first and second burners 1A and 1B is used as a non-combustion burner 1B'. However, the free area AR for installing the burner is provided on the installation area side of the second burner 1B, but the present invention is not limited to this. For example, a part of the first burner 1A may be a non-combustion burner, or a free area for installing a burner may be provided on the installation area side of the first burner 1A. It is also possible to use a one-can, one-circuit system.
The water heater in the present invention means a device having a function of generating hot water, and is used for various hot water supply devices such as general hot water supply, bath hot water supply, heating, or snow melting, and other than hot water supply. Includes a wide range of devices for producing hot water.

WH, WHa Hot water device C Combustion device HE heat exchanger 1B Second burner (burner)
1B'Non-combustion burner 11 Gas inlet 12 Flame hole surface 13 Flow path 14a One end (of non-combustion burner)
14b The other end (of the non-combustion burner)
2 Burner case 3 Fan 4 Fuel gas supply head 6B Second heat transfer tube (heat transfer tube)
60 Straight pipe body part 60a (60) Water inlet side Straight pipe body part 62a Water inlet

Claims (4)

It is equipped with a combustion device and a heat exchanger.
The combustion device includes a burner case that accommodates a plurality of burners side by side, a fan that can supply combustion air into the burner case from below, and a fuel gas that can supply fuel gas to the plurality of burners. Equipped with a supply head,
The heat exchanger is located above the plurality of burners and includes a heat transfer tube through which hot water supplied from a water inlet flows.
The heat transfer tube has a plurality of straight tube bodies extending in a substantially horizontal direction intersecting the side-by-side direction of the plurality of burners, and the plurality of straight tube body portions are arranged in the side-by-side direction. It is a water heating device that is configured to be connected in a series.
In the heat exchanger, among the plurality of straight pipes, the straight pipe located at one end in the side-by-side direction is the water inlet side straight pipe closest to the water inlet.
A part of the plurality of burners is a non-combustion burner that does not cause drive combustion because the fuel gas supply from the fuel gas supply head is constantly stopped, and the burner is inserted above the non-combustion burner. A water heating device characterized by the location of a straight tube on the water side. The hot water apparatus according to claim 1.
The plurality of burners including the non-combustion burner have a gas inlet and an upward-opening flame hole surface.
In the plurality of burners other than the non-combustion burner, a mixed gas of combustion air and fuel gas introduced into the inside from the gas introduction port is made combustible on the flame hole surface.
The non-combustion burner is a hot water device having a configuration in which combustion air introduced into the inside from the gas introduction port flows upward from the flame hole surface. The water heating device according to claim 2.
The non-combustion burner has a form extending in the longitudinal direction of the water inlet side straight pipe portion, and the gas introduction port is provided at one end in the longitudinal direction, and the inside thereof is A gas flow path is formed in which the combustion air flowing into the gas inlet is advanced toward the other end in the longitudinal direction and then upward to be guided to the flame hole surface.
A water heating device having a structure in which hot water flowing from the water inlet of the water inlet side straight pipe portion flows in a direction from the other end side of the non-combustion burner toward the one end side. It is equipped with a combustion device and a heat exchanger.
The combustion device includes a burner case that accommodates a plurality of burners side by side, a fan that can supply combustion air into the burner case from below, and a fuel gas that can supply fuel gas to the plurality of burners. Equipped with a supply head,
The heat exchanger is located above the plurality of burners and includes a heat transfer tube through which hot water supplied from a water inlet flows.
The heat transfer tube has a plurality of straight tube bodies extending in a substantially horizontal direction intersecting the side-by-side direction of the plurality of burners, and the plurality of straight tube body portions are arranged in the side-by-side direction. It is a water heating device that is configured to be connected in a series.
In the heat exchanger, among the plurality of straight pipes, the straight pipe located at one end in the side-by-side direction is the water inlet side straight pipe closest to the water inlet.
In the burner case, a free area for installing a burner is provided in which it is possible to additionally install another burner having the same configuration as each of the burners without arranging any of the plurality of burners, and the burner is provided. A water heating device, characterized in that the water inlet side straight pipe body portion is located above the vacant area for installation.

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