JP3005156B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus for storing hot water in a plurality of hot water storage tanks by one heater and supplying hot water from each of the hot water storage tanks.

[0002]

2. Description of the Related Art Conventionally, this type of hot water supply device has a plurality of hot water storage tanks installed in close proximity to a place of use such as a bath, a kitchen, a washroom, and the like, thereby reducing the installation space at one place. The length of the hot water pipe from the hot water storage tank can be shortened, and hot water can be supplied quickly. In addition, hot water can be stored in a plurality of hot water storage tanks by using only one heater.

As shown in FIG. 6, for example, such a hot water supply apparatus includes a first hot water storage tank 1a and a second hot water storage tank 1b.
The hot water storage tanks 1a and 1b are connected to a tapping pipe 2 at an upper part and a water supply pipe 3 is connected to a lower part. Further, a heating path 6 to which a heater 4 and a circulation pump 5 are connected is provided. An upper circulation pipe 7 is connected to one end of the heating path 6, and the upper circulation pipe 7 is connected to the upper part of each of the hot water storage tanks 1a and 1b. And a lower circulation pipe 8 is connected to the other end of the heating path 6, and the lower circulation pipe 8 is connected to each of the hot water storage tanks 1a and 1b.
Are connected to each other at the lower part. Electric valves 9a and 9b are connected to the divided upper circulation pipe 7, respectively.

In order to store hot water in the first hot water storage tank 1a, the motor-operated valve 9a is opened while the motor-operated valve 9b is closed, and the circulating pump 5 is operated.
The normal temperature water at the lower part of the tank is boiled by the heater 4, and the boiled water is poured into the upper part of the first hot water storage tank 1a. The hot water injected into the upper part of the first hot water storage tank 1a is stored without being mixed with the normal temperature water due to a difference in specific gravity with the normal temperature water on the lower side. In this way, the hot water boiled from the upper side of the first hot water storage tank 1a is sequentially stored.

To store hot water in the second hot water storage tank 1b, the electric valve 9a is closed and the electric valve 9b is opened, so that the second hot water is stored in the second hot water storage tank 1a in the same manner as in the first hot water storage tank 1a. The hot water boiled from the upper side of the hot water storage tank 1b is sequentially stored.

[0006]

However, in the conventional hot water supply apparatus, hot water cannot be moved between the hot water storage tanks. For this reason, a hot water supply device that is configured to heat water only during a specific time period, such as a midnight power time period, is used, for example, when the hot water in one of the hot water storage tanks for the kitchen runs out, the other hot water storage tank for the bath is used. Even if hot water remains in the kitchen, the hot water cannot be used in the kitchen.

[0007] The present invention has been made in view of such a point, and an object of the present invention is to provide a hot water supply device capable of moving hot water stored in a hot water storage tank to another hot water storage tank.

[0008]

According to a first aspect of the present invention, there is provided a hot water supply apparatus comprising: a plurality of hot water storage tanks having a hot water supply port at an upper part and a water supply port at a lower part; a heating path having a heater and a circulation pump; An upper circulation pipe connected to one end of the path and branched and connected to an upper part of each of the hot water storage tanks, and a lower circulation pipe connected to the other end of the heating path and branched and connected to a lower part of each of the hot water storage tanks A pipe, an upper electric valve provided in each of the branched upper circulation pipes, a lower electric valve provided between the heating path and the lower circulation pipe, and connected between the circulation pump and the lower electric valve. And a moving pipe branched and connected between the upper electric valve of the branched upper circulation pipe and the hot water storage tank, respectively, and a moving pipe provided on the branched moving pipe. It is obtained by a moving electric valve.

A hot water supply apparatus according to a second aspect of the present invention has a plurality of hot water storage tanks having a hot water supply port at an upper part and a water supply port at a lower part, a heating path having a heater and a circulation pump, and one end of the heating path. An upper circulation pipe branched and connected to an upper part of each of the hot water storage tanks; a lower circulation pipe connected to the other end of the heating path and branched and connected to a lower part of each of the hot water storage tanks; And an upper motor-operated valve provided between the upper circulation pipe, a lower motor-operated valve provided in each of the branched lower circulation pipes, and the upper motor-operated valve connected between the circulation pump and the upper motor-operated valve. A moving pipe branched and connected between the lower motorized valve of the lower circulation pipe and the hot water storage tank, and a moving motorized valve respectively provided on the branched moving pipe; It includes those were.

[0010]

In the hot water supply apparatus according to the first aspect, at the time of boiling, the upper electric valve and the lower electric valve of the upper circulation pipe connected to the hot water storage tank for boiling are opened to circulate the hot water tank and the heating path. A passage is formed, and hot water boiled by the heater is injected into the upper part of the hot water storage tank by the circulation pump to store the hot water. Also, at the time of hot and cold water transfer, an electric motor valve for moving the transfer pipe connected to the upper circulation pipe connected to the hot water storage tank of the hot water transfer source and an upper electric valve of the upper circulation pipe connected to the hot water storage tank to which the hot water is transferred. Is opened to form a hot water path from the top of the hot water storage tank at the source of the hot water transfer via the circulation pump to the top of the hot water storage tank at the destination of the hot water transfer, and the hot water is moved to the destination by the circulation pump.

In the hot water supply apparatus according to the second aspect, at the time of boiling, the upper motor-operated valve and the lower motor-operated valve of the lower circulation pipe connected to the hot water storage tank for boiling are opened to open the hot water tank and the heating path. A circulation path is formed, and hot water boiled by a heater is injected into the upper part of the hot water storage tank by a circulation pump to store the hot water. In addition, at the time of hot and cold water transfer, the lower electric valve of the lower circulation pipe connected to the hot water storage tank of the hot water transfer destination and the electric motor valve of the transfer pipe connected to the lower circulation pipe connected to the hot water storage tank of the hot water transfer source, Is opened to form a normal temperature water movement path from the lower part of the hot water storage tank at the destination of the hot water transfer via the circulation pump to the lower part of the hot water storage tank at the source of the hot water transfer, and the normal temperature water is moved to the source of the hot water supply by the circulation pump. Along with this, the hot water in the upper part of the hot water storage tank of the hot water transfer source is pushed out to the upper circulation pipe, and the hot water is moved to the upper part of the hot water storage tank of the hot water transfer destination through the upper circulation pipe. That is, by moving the room temperature water in the lower part of the hot water storage tank by the circulation pump, the hot water is moved between the hot water storage tanks in a direction opposite to the moving direction of the room temperature water.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of one embodiment of the hot water supply apparatus of the present invention will be described below with reference to FIGS.

In FIG. 1, T1 and T2 are hot water storage tanks which employ a water-supply hot water supply system of a push-up type, and a hot water supply port 11 is provided above each of the hot water storage tanks T1 and T2, and a water supply port 12 is provided below. Hot water outlet pipes each having a water stopcock 13a at each hot water inlet 11
A water supply pipe 14 connected to a water pipe (not shown) is connected to each water supply port 12. Each of the hot water storage tanks T1 and T2 is provided with a plurality of temperature sensors S1 and S2, which will be described later, for detecting the temperature of hot and cold water in the hot water storage tanks T1 and T2.

A heating path 15 has a heater 16 connected to one end of the heating path 15 and a circulation pump 17 connected to the other end. The heater 16 has a heater 18 for boiling water at a predetermined temperature, and the circulation pump 17 allows the water to flow from the other end of the heating path 16 to one end.

An upper circulation pipe 19 is connected to one end of the heating path 15.
a and 19b are connected, and the upper circulation pipes 19a and 19b are connected to the upper portions of the hot water storage tanks T1 and T2, respectively. The lower circulation pipes 20a and 20b are connected to the other end of the heating path 15, and the lower circulation pipes 20a and 20b are connected to the hot water storage tanks T1 and T2.
Is connected to the lower part of each.

The upper circulation pipes 19a and 19b are respectively provided with upper motor-operated valves B1 and B2 such as solenoid valves. A lower electric valve B3 is mounted between the heating path 15 and the lower circulation pipes 20a and 20b.

A collecting pipe section 22 of the transfer pipe 21 is connected between the circulation pump 17 and the lower electric valve B3, and branch pipe sections 23a and 23b of the transfer pipe 21 are connected to upper electric pipes of the upper circulation pipes 19a and 19b. They are connected between the valves B1, B2 and the hot water storage tanks T1, T2, respectively. The motorized valves B4, B for moving are connected to the branch pipe sections 23a, 23b.
5 are attached respectively.

FIG. 2 shows control means for controlling the hot water supply apparatus.
The control means 31 is connected to a plurality of temperature sensors S1 and S2 of each of the hot water storage tanks T1 and T2, and an operation section 32, from which detection signals and operation signals are input, respectively. The pump 17, the heater 18, and the electric valves B1 to B5 are connected to each other and control them.

The control means 31 comprises temperature sensors S1, S2
Of remaining hot water in the hot water storage tanks T1 and T2 based on the detected temperature of the hot water, a function to heat water during a specific time period such as midnight power hours, and a delay in energization start time for heating Peak shift function, both hot water storage tanks T
It has a function of movement control means for moving hot and cold water between 1 and T2.

The peak shift function is intended not only for the purpose of leveling out the intensive use of electric power immediately after entering the specific time zone, but also for making the boiling up close to the end point of the specific time zone, thereby increasing the boiling. Eliminate wasted heat radiation
The power saving effect is obtained.

Next, the operation of this embodiment will be described.

In the hot water supply device, the hot water storage tanks T1 and T2 are installed close to the use places such as a bath, a kitchen, and a lavatory, so that one installation space can be reduced and the space can be effectively used. Hot water can be supplied quickly by shortening the length of tapping pipe 13 from hot water storage tanks T1, T2. In addition, hot water can be stored in the hot water storage tanks T1 and T2 by using only one heater 16.

First, with reference to the flowchart of FIG. 3, the boiling in a specific time zone such as a midnight power time zone will be described.

When a specific time zone is entered (step 1), the amount of remaining hot water in each of the hot water storage tanks T1 and T2 is checked (step 2).
Check the boiling temperature and the amount of hot water set for each of the hot water storage tanks T1 and T2 (step 3).
The peak shift that enables hot water storage to T1 and T2 is confirmed, and the priority boiling order is determined for which of the hot water storage tanks T1 and T2 is to be heated with priority (step 4).

If the priority boiling order is from one of the hot water storage tanks T1, the boiling operation for the hot water storage tank T1 is performed (step 5). If the priority is from the other hot water storage tank T2, the boiling operation for the hot water storage tank T2 is performed. The operation is performed (step 6), and when the hot water of a predetermined temperature and the amount of hot water remains in both hot water storage tanks T1 and T2, the hot water storage operation is not performed.

In the case where one of the hot water storage tanks T1 is to be preferentially boiled, the boiling temperature and the amount of hot water are checked (step 7). (Steps 8 and 9), the electric valves B1 and B3 are opened (Step 10), the heater 18 of the heater 16 is turned on, and the circulation pump 17 is turned on (Steps 11 and 12).

Thus, from the lower part of the hot water storage tank T1, the lower circulation pipe 20a, the lower electric valve B3, the circulation pump 17, the heater
16, a circulation path to the upper part of the hot water storage tank T1 is formed through the upper electric valve B1 and the upper circulation pipe 19a. Then, the normal temperature water at the lower part of the hot water storage tank T1 is heated to a predetermined temperature by the heater 16, and the heated hot water is injected into the upper part of the hot water storage tank T1. The hot water poured into the upper part of the hot water storage tank T1 is stored without being mixed with the normal temperature water due to a difference in specific gravity with the normal temperature water on the lower side. Hot water boiled from the upper side of the hot water storage tank T1 in this manner is sequentially stored.

Also, when the other hot water storage tank T2 is to be preferentially boiled, the boiling temperature and the amount of hot water are checked (step 13) as in the case of one hot water storage tank T1, and the peak shift is performed. After a lapse of a predetermined time after entering the specific time zone (steps 14 and 15), the motorized valves B2 and B3
Is opened (step 16), the heater 18 of the heater 16 is turned on, and the circulation pump 17 is turned on (steps 11 and 1).
2).

Thus, from the lower part of the hot water storage tank T2, the lower circulation pipe 20b, the lower electric valve B3, the circulation pump 17, the heater
16, a circulation path to the upper part of the hot water storage tank T2 is formed through the upper electric valve B2 and the upper circulation pipe 19b. Then, the room temperature water at the lower part of the hot water storage tank T2 is heated to a predetermined temperature by the heater 16, and the heated hot water is injected into the upper part of the hot water storage tank T2. The hot water poured into the upper part of the hot water storage tank T2 is stored without being mixed with the normal temperature water due to a difference in specific gravity with the normal temperature water on the lower side. Hot water boiled from the upper side of the hot water storage tank T2 in this manner is sequentially stored.

When hot water of a predetermined temperature and quantity is stored in the hot water storage tank T1 (or hot water storage tank T2) which has been preferentially heated (step 17), another hot water storage tank T2 (or hot water storage tank) is prepared. Check if there is a boiling request in T1) (step 18). If there is a request for boiling other hot water storage tank T2 (or hot water storage tank T1),
While the heater 18 and the circulation pump 17 are turned on,
Close the electric valve B1 and open the electric valve B2 (or open the electric valve B1 and close the electric valve B2).
(Or hot water storage tank T1).

Further, after boiling the hot water storage tank T1 (or hot water storage tank T2), the other hot water storage tank T2 (or hot water storage tank T1) is not required to be heated, or both hot water storage tanks T1, When the boiling of T2 is completed, the heater 18 of the heater 16 is turned off and the circulation pump 17 is turned off (steps 20 and 21).
B1 to B3 are closed (step 22).

As described above, the boiling water is stored in each of the hot water storage tanks T1, T2. When the water stopcock 13a provided at the tip of the tapping pipe 13 of each of the hot water storage tanks T1 and T2 is opened, the pressure of tap water supplied from the water supply pipe 14 causes the hot water in the upper part of each of the hot water storage tanks T1 and T2 to be opened. Is taken out.

After the boiling of both hot water storage tanks T1 and T2 is completed, the temperature of the hot water stored in hot water storage tanks T1 and T2 is monitored during a specific time zone. The process may return to step 10 or step 16 to maintain the predetermined temperature.

Next, referring to the flow chart of FIG. 4, as a countermeasure when the remaining hot water amount of one of the hot water storage tanks T1 and T2 becomes small or the hot water runs out during a time period other than the specific time zone, The movement of hot and cold water between T2 will be described.

The movement of hot and cold water between the hot water storage tanks T1 and T2 is as follows.
There are a case where a movement selection instruction for designating a moving direction of hot and cold water is made by the operation unit 32, and a case where uniform movement of hot and cold water is instructed.

When the remaining hot water in one of the hot water storage tanks T1 and T2 becomes small or the hot water runs out, the operation unit
If a move selection is instructed in step 32 (step 31), it is first checked whether there is a move amount instruction (step 32), and if there is an instruction, the move amount is set. It is set (step 33), and the amount of movement is confirmed (step 34).

Subsequently, it is checked whether or not there is remaining hot water at the hot water source in the hot water storage tanks T1 and T2 (step 35).

If there is remaining hot water at the hot water source of the hot water storage tanks T1 and T2, the movement of the hot water is determined by the hot water storage tank T1.
When the hot water is stored in the hot water storage tank T2, the electric valves B2 and B4 are opened (steps 37 and 38) and the circulation pump 17 is turned on (step 3).
9).

Thus, from the upper part of the hot water storage tank T1, the upper circulation pipe 19a, the branch pipe part 23a of the transfer pipe 21, the motorized valve B4, the collecting pipe part 22 of the transfer pipe 21, the circulation pump 17,
Through the heater 16, the upper motor-operated valve B2, and the upper circulation pipe 19b,
A hot water path is formed to reach the upper part of the hot water storage tank T2, and the hot water of the hot water storage tank T1 is moved to the hot water storage tank T2.

When the hot water destination is the hot water storage tank T2 to the hot water storage tank T1, the electric valves B1 and B5 are opened (step 4).
0), the circulation pump 17 is turned on (step 39).

Thus, from the upper part of the hot water storage tank T2, the upper circulation pipe 19b, the branch pipe part 23b of the transfer pipe 21, the moving electric valve B5, the collecting pipe part 22 of the transfer pipe 21, the circulation pump 17,
Through the heater 16, the upper electric valve B1, and the upper circulation pipe 19a,
A hot water moving path that reaches the upper part of the hot water storage tank T1 is formed, and the hot water of the hot water storage tank T2 is moved to the hot water storage tank T1.

When the movement amount of the hot water between the hot water storage tanks T1 and T2 reaches the set value or the remaining hot water amount at the source of the hot water reaches a predetermined value and the movement is completed (step 41), the circulation pump 17 is turned off and the electric motor is turned off. The valves B2 and B4 (or the electric valves B1 and B5) are closed (steps 42 and 43), and the process returns to step 31.

The amount of hot water transferred between the hot water storage tanks T1 and T2 is detected by a plurality of temperature sensors S1 and S2 attached to the hot water storage tanks T1 and T2 along the vertical direction. Can be confirmed by

Further, if there is an instruction for uniform movement on the operation unit 32 (step 44), the remaining hot water amounts in the hot water storage tanks T1 and T2 are confirmed, and the equalizing process for obtaining the moving direction and the moving amount required for equalization is performed. Is performed (step 45).

Subsequently, it is confirmed whether or not movement between the hot water storage tanks T1 and T2 is possible (step 46), and if movement is impossible, an alarm is issued (step 47).

If it is possible to move between the hot water storage tanks T1 and T2, the motor-operated valves B2 and B4 corresponding to the moving direction of hot water
(Or the motor-operated valves B1, B5) are opened (step 48). That is, when moving from hot water storage tank T1 to hot water storage tank T2, electric valves B2 and B4 are opened, and when moving from hot water storage tank T2 to hot water storage tank T1, electric valves B1 and B5 are opened.

When the circulation pump 17 is turned on (step 49), the hot water in the hot water storage tank T1 is changed to the hot water storage tank T2.
The hot water in the hot water storage tank T2 is moved to the hot water storage tank T1.

When the movement amount of the hot water between the hot water storage tanks T1 and T2 reaches the set value and the movement is completed (step 50), the circulating pump 17 is turned off and the electric valves B2 and B4 (or the electric valves) are turned off.
B1 and B5) are closed (steps 51 and 52), and the process returns to step 31.

As described above, hot water is moved between hot water storage tanks T1 and T2. Therefore, even when the remaining hot water volume of one of the hot water storage tanks T1 and T2 becomes small or the hot water runs out during a time period other than the specific time period such as the midnight power time zone,
If hot water remains in the other of the hot water storage tanks T1 and T2, running out of hot water can be prevented by moving the hot water from the other of the hot water storage tanks T1 and T2 to one.

FIG. 5 shows another embodiment of the present invention, in which the circulation pump 17 directly moves hot water above the hot water storage tanks T1, T2. The pump 17 moves the room temperature water under the hot water storage tanks T1 and T2, thereby indirectly moving the hot water above the hot water storage tanks T1 and T2.

The piping structure includes a heating path 15 and an upper circulation pipe.
An upper motor-operated valve B6 is mounted between the lower circulation pipes 19a and 19b, and lower motor-operated valves B7 and B8 are mounted on the lower circulation pipes 20a and 20b, respectively.

Further, a collecting pipe section 22 of a transfer pipe 21 is connected between the circulation pump 17 and the heater 16 (upper motor-operated valve B6), and branch pipe sections 23a and 23b of the transfer pipe 21 are circulated in a lower part. Lower electric valves B7, B8 of pipes 20a, 20b and hot water storage tanks T1, T2
And each is attached between. This branch pipe part 23
Moving electric valves B4 and B5 are connected to a and 23b, respectively.

To heat the hot water storage tank T1, the electric valves B6 and B7 are opened to form a circulation path between the hot water storage tank T1 and the heating path 15, and the heater 18 and the circulation pump 17 are turned on. Room temperature water at the lower part of the hot water storage tank T1 is boiled, and the boiled water is poured into the upper part of the hot water storage tank T1.

To heat the hot water storage tank T2, the electric valves B6 and B8 are opened to open the hot water storage tank T2 and the heating path.
A circulation path is formed with the heating heater 18 and the circulation pump.
17 is turned on to boil the room temperature water at the lower part of the hot water storage tank T2 and to inject the boiled water into the upper part of the hot water storage tank T2.

Next, when the hot water is moved from the hot water storage tank T1 to the hot water storage tank T2, the electric valves B4 and B8 are opened and the room temperature water is transferred from the lower part of the hot water storage tank T2 to the lower part of the hot water storage tank T1 through the circulation pump 17. A passage is formed, and the circulation pump 17 is turned on to inject the room temperature water in the lower part of the hot water storage tank T2 into the lower part of the hot water storage tank T1. Thereby, the hot water in the upper part of the hot water storage tank T1 is pushed out to the upper circulation pipe 19a, and the hot water is moved to the upper part of the hot water storage tank T2 through the upper circulation pipe 19b.

When the hot water is moved from the hot water storage tank T2 to the hot water storage tank T1, the electric valves B5 and B7 are opened, and the room temperature water movement path from the lower part of the hot water storage tank T1 to the lower part of the hot water storage tank T2 through the circulation pump 17 The circulation pump 17 is turned on to inject the room temperature water in the lower part of the hot water storage tank T1 into the lower part of the hot water storage tank T2. Thereby, the hot water in the upper part of the hot water storage tank T2 is pushed out to the upper circulation pipe 19b, and the hot water is moved to the upper part of the hot water storage tank T1 through the upper circulation pipe 19a.

As described above, the hot water storage tank T is
By moving the room-temperature water below 1, 1 and T2, the water is moved between the hot-water storage tanks T1 and T2 in a direction opposite to the moving direction of the room-temperature water. Therefore, even when the remaining hot water volume of one of the hot water storage tanks T1 and T2 becomes small or the hot water runs out during a time period other than a specific time zone such as the midnight power time zone, hot water remains in the other of the hot water storage tanks T1 and T2. Then, by moving the hot water from one of the hot water storage tanks T1 and T2 to the other,
Prevents running out of hot water.

[0058]

According to the hot water supply apparatus of the present invention, the hot water stored in the hot water storage tank can be moved to another hot water storage tank. Even if the hot water runs out, if hot water remains in the other hot water storage tank, the hot water can be prevented from running out by moving the hot water from the other hot water storage tank.

According to the second aspect of the present invention, by moving the room temperature water in the lower portion of the hot water storage tank by the circulation pump, the hot water is moved between the upper portion of the hot water storage tank in a direction opposite to the moving direction of the room temperature water. Even if the amount of remaining hot water in one hot water storage tank decreases or runs out of hot water, if hot water remains in the other hot water storage tank, the hot water can be moved from the other hot water storage tank to the other. It can prevent running out of hot water.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing one embodiment of a hot water supply apparatus of the present invention.

FIG. 2 is a control block diagram of the embodiment.

FIG. 3 is a flowchart at the time of boiling according to the embodiment.

FIG. 4 is a flowchart at the time of hot and cold water transfer of the embodiment.

FIG. 5 is a piping diagram showing another embodiment of the hot water supply apparatus of the present invention.

FIG. 6 is a piping diagram of a conventional hot water supply apparatus.

[Explanation of symbols]

 11 Hot water inlet 12 Water inlet 15 Heating path 16 Heater 17 Circulating pump 19a, 19b Upper circulating pipe 20a, 20b Lower circulating pipe 21 Moving pipe B1, B2 Upper motorized valve B3 Lower motorized valve B4, B5 Moving motorized valve B6 Upper part Motorized valve B7, B8 Lower motorized valve T1, T2 Hot water storage tank

Continuation of front page (56) References JP-A-6-221673 (JP, A) JP-A-1-163553 (JP, A) JP-A-4-32655 (JP, A) JP-A-5-248702 (JP) , A) Hikaru 3-13064 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24H 1/18 F24H 1/18 302

Claims (2)

(57) [Claims] 1. A plurality of hot water storage tanks having a hot water supply port at an upper portion and a water supply port at a lower portion, a heating path having a heater and a circulation pump, and a heating path connected to one end of the heating path and being connected to one end of each of the hot water storage tanks. An upper circulating pipe branched and connected to an upper portion, a lower circulating pipe connected to the other end of the heating path and divergently connected to a lower portion of each of the hot water storage tanks, and provided on the branched upper circulating pipe, respectively. An upper motor-operated valve, a lower motor-operated valve provided between the heating path and the lower circulation pipe, and an upper motor-operated valve of the branched upper circulation pipe connected and connected between the circulation pump and the lower motor-operated valve. And a transfer pipe branched and connected between the storage tank and the hot water storage tank, and a transfer motorized valve provided on each of the branched transfer pipes. That water heater. 2. A plurality of hot water storage tanks having a hot water supply port at an upper part and a water supply port at a lower part; a heating path having a heater and a circulation pump; An upper circulation pipe branched and connected to an upper part respectively; a lower circulation pipe connected to the other end of the heating path and branched to a lower part of each of the hot water storage tanks; and between the heating path and the upper circulation pipe. An upper electric valve provided on the lower circulation valve, and a lower electric valve provided on each of the branched lower circulation pipes; and a lower electric valve of the branched lower circulation pipe connected between the circulation pump and the upper electric valve. And a transfer pipe branched and connected between the storage tank and the hot water storage tank, and a transfer motorized valve provided on each of the branched transfer pipes. That water heater.