KR20210029008A - Water heater with dual heater - Google Patents

Abstract

According to the present invention, provided is a water heating apparatus. The water heating apparatus includes: a primary flow path (110) connected with a water input part (112), wherein water flowing therein through the water input part (112) flows in a first direction; an inner heating part (120) located to surround the primary flow path (110); an outer heating part (130) which is an outer heating part (130) located to surround the inner heating part (120), and located to form a flow path space (S) between the inner heating part (120) and the outer heating part (130); and a secondary flow path (140) provided in the flow path space (S), and having one side connected to the primary flow path (110), and having the other side connected to a water output part (142). Water flowing in the secondary flow path (140) is heated by the inner heating part (120) and the outer heating part (130) at the same time. Therefore, the present invention is capable of maximizing heating efficiency.

Description

Water heater with dual heater {Water heater with dual heater}

The present invention is a hot water device equipped with a dual heater, and more specifically, a hot water device that maximizes heating efficiency by dividing the flow path in the hot water device into a primary flow channel and a secondary flow channel formed in a specific structure and heating each with a heater It is about the technology.

In general, instantaneous water heaters are widely installed and used in homes or buildings of ordinary households where hot water is required. Such an instantaneous water heater is manufactured on the same principle as the hot water supply of a boiler, and is developed to use the required hot water by instantaneously heating the supplied tap water. Instantaneous water heaters do not store heated hot water, but instantaneously heat tap water supplied as cold water, and thus have an advantage of saving energy compared to a boiler system that stores heated hot water.

Instantaneous water heaters are key to how quickly the user can supply hot water at a desired temperature in a short time, and this is a matter of how quickly the water can be heated. Of course, in this process, in addition to simply a fast heating rate, a small power consumption is also required.

In recent years, instantaneous water heaters having various structures have been developed and used so that tap water supplied with little power can be heated in a short time.

As a prior art for an instantaneous water heater, Korean Patent Publication No. 10-2011-0006913 is disclosed. The prior art discloses a configuration for shortening the heating time of hot water by configuring the hot water pipe to form a zigzag shape while forming a bent portion as a technology for a'electric instantaneous water heater'. However, the prior art is a structure that uses a hot water pipe that is bent a plurality of times, and since it is not a structure to which a planar heating heater such as a Lutenox heater can be applied, there is a problem that it cannot be used by miniaturization.

As another prior art, Korean Patent Publication No. 10-2017-0100191 issued by the present applicant is disclosed. The prior art also relates to a'instantaneous water heater', and discloses a configuration for suppressing the generation of overheated steam by the heater unit. However, the prior art is not a structure using a dual heater, and the heating flow channel does not disclose a large structural feature, and the heating efficiency of the heater is not very high.

Accordingly, in recent years, in order to solve the problems of the prior art described above, there is a need for a water heater having a flow path that is easy to install in a narrow space and has excellent heating efficiency of the heater.

(Patent Document 1) Korean Laid-Open Patent No. 10-2011-0006913

(Patent Document 2) Korean Patent Publication No. 10-2017-0100191

(Patent Document 3) Korean Patent Application Publication No. 10-2017-0123977

The present invention was devised to solve the above problems.

An object of the present invention is to propose a structure of a hot water device that is easy to install in a narrow space and maximizes the heating efficiency of a heater.

In addition, the present invention is to propose a structure that facilitates the discharge of air bubbles generated in the heating process inside the hot water device, and is stable against external shock or vibration.

An embodiment of the present invention for solving the above problems, is connected to the receiving unit 112, the first flow passage 110 through which the water introduced through the receiving unit 112 flows in a first direction; An inner heating unit 120 positioned to surround the primary flow path 110; As an outer heating unit 130 positioned to surround the inner heating unit 120, an outer heating unit positioned to form a flow path space S between the inner heating unit 120 and the outer heating unit 130 (130); And a second flow passage 140 provided in the flow path space S, one side communicating with the primary flow passage 110, and the other side communicating with the water outlet 142; Including, the water flowing through the secondary flow path 140 provides a hot water device formed to be heated simultaneously by the inner heating unit 120 and the outer heating unit 130.

In addition, the primary flow path 110 may have a pipe shape extending in the first direction, and the secondary flow path 140 may be formed as a spiral flow path.

In addition, the primary flow path 110 is communicated with the inlet of the secondary flow path 140 by a flow path connection unit 150 provided at an end side, and the flow path connection unit 150 flows in the first direction. Discharged water is discharged in an outward direction to flow to the inlet of the secondary flow path 140, and the flow path space S may be formed to extend in a second direction opposite to the first direction.

In addition, in the flow path space S, a spiral flow guide member 144 extending along the second direction is provided, and the outlet portion 142 is disposed at an end side of the flow path space S in the second direction. Doedoe formed, the second direction and a predetermined angle may be formed and bent.

In addition, the inner heating unit 120 may include an inner heater 122 provided on an outer surface of the primary channel 110 and an inner tube 124 covering the inner heater 122; Including, the outer heating part 130, the outer pipe 132 forming the flow path space together with the inner pipe 124; And an outer heater 134 provided on the outer surface of the outer tube 132; It may include.

In addition, the end of the inner tube 124 is formed to extend by a predetermined length more than the end position of the primary flow path 110, and the flow path connecting portion 150, on the outer circumferential surface, protrudes outward, It includes a first protruding jaw 151 and a second protruding jaw 152 having different protrusion heights, and partially inserted and fixed to the end side of the primary flow path 110, and the first protruding jaw 151 is It is caught on the end of the primary flow path 110, the second protrusion 152 may be formed to be caught on the end of the inner tube 124.

In addition, the flow path connection unit 150 is in the shape of a hollow, but has at least one discharge port 153 that is open in an outward direction at an end side based on the first direction, and the discharge port 153 is the flow path space It can communicate with the entrance of (S).

In addition, a protrusion 154 protruding outward is formed on an outer circumferential surface of the inlet side of the flow path connection part 150, and a first O-ring member 155 is positioned between the protrusion 154 and the first protruding protrusion 151 And, a second O-ring member 156 is positioned between the first protruding jaw 151 and the second protruding jaw 152, and the first O-ring member 155 includes an inner circumferential surface of the primary flow path 110 and a flow path. It seals between the outer surface of the connection part 150, and the second O-ring member 156 may seal between the outer surface of the flow path connection part 150 and the inner circumferential surface of the inner tube 124.

Further, based on the first direction, an end of the outer tube 132 is closed by a cap sealing unit 160, and a temperature sensor 170 may be mounted on the cap sealing unit 160.

In addition, the sensing tip 172 provided in the temperature sensor 170 senses the temperature of water discharged from the primary flow path 110, but senses the temperature before flowing into the secondary flow path 140. It may be located at the end side of the inside of the flow path connection part 150.

In addition, a cover housing 180 configured to cover portions excluding the intake part 112 and the outlet part 142 and to be separated and coupled to the upper housing 182 and the lower housing 184; It may further include.

In addition, the inner heating unit 120 and the outer heating unit 140 may include a planar heating unit.

In addition, the inner heating unit 120, a first inner heater having a first output; And a second inner heater having a second output. And the first inner heater and the second inner heater may be spaced apart from each other at a predetermined interval based on the first direction.

In addition, the intake part 112 is formed to supply water in the first direction from the inlet of the primary flow path 110, and the water outlet 142 is formed at the end side of the secondary flow path 140. However, it may be formed to discharge water in a direction perpendicular to the first direction.

In addition, a control unit for adjusting the output of the inner heating unit 120 and the outer heating unit 130; It further includes, and the control unit may be formed to drain the primary flow path 110 and the secondary flow path 140 to discharge air bubbles in the flow path according to a preset condition.

The hot water device according to the present invention is formed differently as a primary flow path that serves as a buffer and a secondary flow path that forms a spiral flow path, so that air bubbles generated during the heating process of the heater can be easily discharged, and accordingly, the heating efficiency is lowered. It exerts an effect that can prevent the problem from becoming a problem.

In addition, the hot water device according to the present invention has a structure in which a secondary flow path is formed as a spiral flow path, and both sides of the secondary flow path can be heated simultaneously with an inner heater and an outer heater. By maximizing it, it exerts an effect that can maximize the heating efficiency.

1 is an exploded perspective view of a hot water device according to the present invention.
2 is a cross-sectional view of a hot water device according to the present invention.
3 is an overall perspective view of a hot water device according to the present invention.
4 is a front view of the hot water device according to the present invention.
5 is a plan view of a hot water device according to the present invention.
6 is a right side view of the hot water device according to the present invention.

Hereinafter, a hot water apparatus according to an embodiment of the present invention will be described with reference to the drawings.

The terms'inlet' and'outlet' used for explanation refer to the start side of the flow path as the'inlet', and the end side of the flow path as the'exit' based on the flow direction of water.

A configuration of a hot water device according to the present invention will be described with reference to FIGS. 1 and 2.

The hot water apparatus 100 according to the present invention includes a primary flow channel 110, an inner heating unit 120, an outer heating unit 130, and a secondary flow channel 140.

The'primary flow path 110' has a pipe shape extending in the first direction, and provides a space in which water supplied from the intake unit 112 primarily flows. Based on the first direction, the inlet 112 is mounted at the inlet of the primary channel 110, and the inlet of the primary channel 110 is sealed through the mounting of the inlet unit 112. For tighter sealing, it is preferable that an O-ring member is mounted between the inlet of the receiving part 112 and the primary flow path 110.

An inlet pipe 112a, which is relatively smaller than the diameter of the primary channel 110, is formed in the inlet part 112, and the inlet pipe 112a is also a structure extending in the first direction. In order to stably support one end of the inner heating unit 120 to be described later in the acquisition unit 112, a wing frame 112b is formed.

The inlet pipe (112a) is fastened with the inlet pipe fitting (113), and Fig. 2 shows a structure in which the inlet pipe fitting (113) is bent, but depending on the installation environment of the hot water device (100), inlet pipes of various shapes Fitting 113 may be used. At the outlet of the primary flow path 110, a flow path connection unit 150, which will be described later, is mounted.

'Inner heating part 120 is formed to surround the primary flow path 110. Specifically, it includes an inner heater 122 and an inner tube 124. The inner heater 122 is provided on the outer surface of the primary flow path 110, is a planar heating heater having a curvature corresponding to the cross-sectional curvature of the primary flow path 110, and a Lutenox heater is used. desirable.

The inner heater 122 and the outer heater 134 applied to the present invention are planar heating heaters, and separate illustrations thereof are omitted in FIG. 2 and are replaced with the following description.

The inner pipe 124 serves to cover the inner heater 122 in order to prevent water from penetrating the electric device into the inner heater 122. At this time, the inner heater 122 is provided on the outer circumferential surface of the primary channel 110, and is spaced apart from the inlet of the primary channel 110 at a predetermined interval. This is to improve the heating efficiency since the inlet side of the primary flow path 110 in which the intake part 112 is located has a relatively high water flow rate. That is, the outer circumferential surface of the primary flow path 110 is divided into an exposed portion 110a and a cover portion of the inner heater 122, and the inner tube 124 is preferably formed to surround the cover portion of the inner heater 122 Do.

On the other hand, the outlet of the inner pipe 124 (meaning the end based on the water flow path) is formed to extend a predetermined length longer than the outlet (end) of the primary flow path 110, and the primary flow path 110 And a description of the outlet of the inner tube 124 will be described later.

The'outer heating part 130' is located outside the inner heating part 120 and is formed to surround the inner heating part 120. At this time, the outer heating part 130 is not a structure that tightly surrounds the inner heating part 120, but in a radial direction to form a flow path space S between the inner heating part 120 and the outer heating part 130. It is formed so as to be spaced apart by a predetermined distance and wrapped.

More specifically, the outer heating unit 130 is composed of an outer tube 132 and an outer heater 134. The outer pipe 132 is formed to be spaced apart from the inner pipe 124 in the radial direction, thereby forming a flow path space S, and a secondary flow path 140 is located in the flow path space S. Here, the flow path space S means an empty space, and a spiral flow guide member 144 that substantially guides the flow path is provided in the flow path space S, which is an empty space.

The end of the outer tube 132 extends longer than the end of the inner tube 124, and the cap sealing portion 160 is closely coupled to the end of the outer tube 132, so that the end of the outer tube 132 is closed. do.

The'second flow path 140' is a spiral flow path provided in the flow path space S. In order to form a spiral flow path in the flow path space S, a separate member of the spiral flow guide member 144 may be inserted, and the spiral flow guide member 144 may be formed of a spring having a predetermined elasticity. Of course, the spiral flow guide member 144 may be formed integrally with the inner pipe 124 and the outer pipe 134 between them. Here, the flow path space S has a structure extending in a second direction, which is a direction opposite to the first direction, based on the flow direction.

The above-described primary flow path 110 primarily heats water by the inner heater 122 while flowing water in the first direction, and the outlet of the primary flow path 110 is the inlet of the secondary flow path 140 and Communicate. Water that has flowed in the first direction due to the water pressure of the water supplied through the intake unit 112 flows again in the second direction in the second direction, opposite to the first direction in the secondary flow path 140.

The secondary flow path 140 through which water flows in the second direction flows between the inner heater 122 and the outer heater 134, and heats it by receiving thermal energy from the inner heater 122 and the outer heater 134 at the same time. do. In addition, the secondary flow path 140 has an obstacle called a spiral flow guide member 144, unlike the primary flow path 110, which does not have a separate obstacle. As the frictional area with the obstacle increases, the flow velocity temporarily decreases. In a reduced state, it flows in a helical manner along the outer surface of the spiral flow guide member 144.

In this way, by forcibly reducing the flow rate of water in a section in which heat energy can be transmitted from both the inner heater 122 and the outer heater 134, the heat transfer time of the inner heater 122 and the outer heater 134 can be increased. And, through this, it is possible to maximize heating efficiency or hot water generation efficiency.

On the other hand, the discharge of air bubbles inside the hot water device will be described. Conventional water heaters using a spiral flow path have a fatal problem in that air bubbles generated during the heating process cannot be removed and stagnate on the spiral flow path, causing a failure of the water heater.

In order to solve this problem, the hot water apparatus 100 according to the present invention has a structure capable of performing the function of a buffer by temporarily storing a relatively large amount of water. In order for the strong water pressure to be transmitted from the outlet of the primary channel 110 to the inlet of the secondary channel 140, it must be premised that the inside of the primary channel 110 is filled with water.

As the strong water pressure of the water filled in the primary channel 110 is transferred to the secondary channel 140, it is easy to discharge it to the outside even if there are air bubbles in the secondary channel 140.

The'channel connection unit 150' serves to communicate the outlet of the primary flow path 110 and the inlet of the secondary flow path 140. Specifically, the flow path connection unit 150 has at least one discharge port 153 formed at the end side, and is opened in a radial direction or an outward direction, so that the flow direction of water discharged from the primary flow path 110 can be switched to the opposite direction. have.

That is, through the outlet 153 of the flow path connector 150, water that has flowed in the first direction is converted into a second direction that is opposite to the first direction. The flow path connection unit 150 is formed in a hollow shape and has a structure through which water can pass.

The first protruding jaw 151 and the second protruding jaw 152 are formed on the outer circumferential surface of the flow path connection unit 150 to protrude outward, and having different protrusion heights. A portion before the first protruding protrusion 151 based on the longitudinal direction of the flow path connection part 150 is inserted and fixed at the end side of the primary flow path 110, and a first O-ring member 155 is provided for tight fixing. .

The first protruding jaw 151 is formed to be caught on the end of the primary flow path 110, and the second protruding jaw 152 is formed to be caught on the end of the inner tube 124, so that it can be stably fixed. That is, the vibration in the first direction or the second direction may be supported by the first protruding jaw 151 and the second protruding jaw 152.

On the outer circumferential surface of the flow path connection part 150, a protrusion 154, a first protrusion 151, and a second protrusion 152 are sequentially formed (based on the first direction). At this time, the first O-ring member 155 is positioned between the protrusion 154 and the first protruding jaw 151, and a second O-ring member ( 156) is located. The first O-ring member 155 seals between the inner circumferential surface of the primary flow path 110 and the outer surface of the flow path connection unit 150, and the second O-ring member 156 is formed between the outer surface of the flow path connection unit 150 and the inner circumferential surface of the inner tube 124. Close it.

The flow path connection unit 150 serves to change the flow path between the primary flow path 110 and the secondary flow path 140, and is a configuration in which strong water pressure is applied, and the flow path connection unit 150 is stable from external force. It is necessary to support it. The flow path connection unit 150 of the hot water device 100 according to the present invention is not a structure coupled to a single configuration, but a structure complexly fixed to both the primary flow path 110 and the inner tube 124, In addition to being able to stably disperse vibration, it is also possible to provide a stable fixing force.

As described above, the'cap sealing unit 160' closes the end of the outer tube 132 and provides a space in which the temperature sensor 170 is mounted. The temperature sensor 170 is connected to a control unit (not shown) built in the hot water device 100 by wire/wireless connection to provide temperature information inside the flow path. The sensing tip 172 provided in the temperature sensor 170 senses the temperature of water discharged from the primary flow path 110, but the flow path connection part 150 to sense the temperature before flowing into the secondary flow path 140 It is located on the side of the distal end of the inside. Accordingly, the temperature change information by the inner heater 122 and the temperature change information by the outer heater 134 can be most accurately provided.

At this time, the control unit is configured to adjust the outputs of the inner heating unit 120 and the outer heating unit 130 through temperature information, and the inner heating unit 120 and the outer heating unit 130 according to the user's input temperature. Output condition can be controlled. When the user inputs a temperature value corresponding to the lukewarm water, only the inner heater 122 or only the outer heater 134 may be operated.

In addition, the control unit is formed to drain the primary flow path 110 and the secondary flow path 140 and discharge air bubbles in the flow path according to a preset condition. For example, in spite of operating the inner heater 122 and/or the outer heater 134, when the temperature value sensed from the temperature sensor 170 is significantly lower than the target temperature, the inside of the hot water device 100 Algorithms can be designed to drain the air bubbles and drain them.

Meanwhile, both the inner heater 122 and the outer heater 134 of the hot water apparatus 100 according to the present invention may have an output value of 2700W. At this time, the inner heater 122 may be operated by being divided into two heaters. The inner heater 122 is composed of a first inner heater 120a having a first output and a second inner heater 120b having a second output, and these are arranged spaced apart at a predetermined interval based on the first direction. Can be. For example, the first output may be an output value of 1300W, and the second output may be formed as an output value of 1400W.

It is preferable that the intake part 112 and the outlet part 142 according to the present invention are designed to be deflected in one direction. This is because the water flowing in the primary flow path 110 flows in the reverse direction again in the secondary flow path 140.

The water outlet 142 is formed at the end side of the secondary flow path 140, and is formed to discharge water in a direction perpendicular to the first direction, so that the water flow rate is forcibly changed during the water outlet process. . The water outlet 142 is formed to be coupled to the water outlet fitting 143, and a shower module may be mounted on the water outlet fitting 143.

3 to 6 show the appearance of the hot water device according to the present invention. The hot water device 100 is covered by a cover housing 180. The cover housing 180 is configured to cover all of the rest except for the opening for connecting the inlet 112, the outlet 142, and the power supply line. Referring back to FIG. 1, both the inner heater 122 and the outer heater 134 have terminal portions 122a and 134a connected to the power supply line, respectively. It is preferable to be configured to be separated and coupled into the upper housing 182 and the lower housing 184, and for more stable coupling, the upper housing 182 and the lower housing 184 are fixed through screw coupling to the coupling hole 186 It is desirable to do it.

In the above, the present specification has been described with reference to the embodiments shown in the drawings so that those skilled in the art can easily understand and reproduce the present invention, but these are only exemplary, and those skilled in the art can use various modifications and equivalents from the embodiments of the present invention. It will be appreciated that examples are possible. Therefore, the scope of protection of the present invention should be determined by the claims.

100: water heater
110: 1st euro
112: acquisition unit
113: inlet pipe fitting
120: inner heating part
122: inner heater
124: inner tube
130: outer heating part
132: outer tube
134: outer heater
140: 2nd euro
142: water outlet
144: flow path guide member
150: flow path connection
151: first protruding jaw
152: second protruding jaw
153: outlet
154: protrusion
155: first O-ring member
156: second O-ring member
160: cap sealing part
170: temperature sensor
172: sensing tip
180: cover housing
182: upper housing
184: lower housing

Claims (15)

A primary flow path 110 connected to the intake part 112 and through which water introduced through the intake part 112 flows in a first direction;
An inner heating unit 120 positioned to surround the primary flow path 110;
As an outer heating unit 130 positioned to surround the inner heating unit 120, an outer heating unit positioned to form a flow path space S between the inner heating unit 120 and the outer heating unit 130 (130); And
It is provided in the flow path space (S), one side is in communication with the primary flow passage 110, the other side is a secondary flow passage 140 in communication with the water outlet 142; Including,
The water flowing through the secondary flow path 140 is formed to be heated simultaneously by the inner heating unit 120 and the outer heating unit 130,
Hot water system.
The method of claim 1,
The primary flow path 110 has a pipe shape extending in the first direction,
The secondary flow path 140 is formed as a spiral flow path,
Hot water system.
The method of claim 2,
The primary flow path 110 is in communication with the inlet of the secondary flow path 140 by a flow path connecting portion 150 provided at an end side,
The flow path connection unit 150,
The water flowing in the first direction is discharged to the outside to flow to the inlet of the secondary flow path 140,
The flow path space (S),
Formed to extend in a second direction opposite to the first direction,
Hot water system.
The method of claim 3,
In the flow path space S, a spiral flow guide member 144 extending toward the second direction is provided,
The water outlet 142 is formed on an end side of the flow path space S in the second direction, and is bent at a predetermined angle with the second direction.
Hot water system.
The method of claim 3,
The inner heating unit 120,
The inner heater 122 provided on the outer surface of the primary flow path 110 and
An inner pipe 124 covering the inner heater 122; Including,
The outer heating part 130,
An outer pipe 132 forming the flow path space together with the inner pipe 124; And
An outer heater 134 provided on the outer surface of the outer tube 132; Containing,
Hot water system.
The method of claim 5,
The end of the inner tube 124 is formed to extend by a predetermined length more than the end position of the primary flow path 110,
The flow path connection unit 150,
On the outer circumferential surface, it protrudes in an outward direction, and includes a first protruding jaw 151 and a second protruding jaw 152 having different protrusion heights, and a part is inserted and fixed at the end side of the primary flow path 110,
The first protruding jaw 151 is formed to be caught on the end of the primary flow path 110, and the second protruding jaw 152 is formed to be caught on the end of the inner tube 124,
Hot water system.
The method of claim 6,
The flow path connection unit 150,
It is in the form of a hollow, but with respect to the first direction, the end side is formed with at least one outlet 153 that is open in an outward direction, and the outlet 153 is in communication with the inlet of the flow path space (S),
Hot water system.
The method of claim 6,
A protrusion 154 protruding outward is formed on an outer peripheral surface of the inlet side of the flow path connection part 150, and a first O-ring member 155 is positioned between the protrusion 154 and the first protruding protrusion 151, A second O-ring member 156 is positioned between the first protruding jaw 151 and the second protruding jaw 152,
The first O-ring member 155 seals between the inner circumferential surface of the primary flow path 110 and the outer surface of the flow path connecting portion 150, and the second O-ring member 156 includes an outer surface of the flow path connecting portion 150 and the inner tube ( 124) Sealing between the inner circumferential surfaces,
Hot water system.
The method of claim 5,
Based on the first direction, the end of the outer tube 132 is closed by the cap sealing unit 160, the temperature sensor 170 is mounted on the cap sealing unit 160,
Hot water system.
The method of claim 9,
The sensing tip 172 provided in the temperature sensor 170,
It senses the temperature of the water discharged from the primary flow path 110, but is located at the end of the inside of the flow path connection 150 to sense the temperature before flowing into the secondary flow path 140,
Hot water system.
The method of claim 1,
A cover housing 180 configured to cover portions excluding the intake part 112 and the water outlet part 142 and to be separated and coupled to the upper housing 182 and the lower housing 184; It further includes,
Hot water system.
The method of claim 1,
The inner heating unit 120 and the outer heating unit 140 include a planar heating heater,
Hot water system.
The method of claim 12,
The inner heating unit 120,
A first inner heater having a first output; And
A second inner heater having a second output; Consists of,
The first inner heater and the second inner heater are arranged to be spaced apart at a predetermined interval based on the first direction,
Hot water system.
The method of claim 1,
The intake part 112 is formed to supply water in the first direction from the inlet of the primary flow path 110,
The water outlet 142 is formed at an end side of the secondary flow path 140, and is formed to discharge water in a direction perpendicular to the first direction,
Hot water system.
The method of claim 1,
A control unit that adjusts the output of the inner heating unit 120 and the outer heating unit 130; It further includes,
The control unit,
According to a preset condition, formed to drain the primary flow path 110 and the secondary flow path 140 to discharge air bubbles in the flow path,
Hot water system.

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