JPH10132378A - Combined hot water feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable correction of the output of a pressure sensor to be easily carried out and shorten the time required to perform automatic hot water feeding operation. SOLUTION: In a combined hot water feeder comprised of a hot water feeding circuit 10 for heating fed water and supplying hot water, a circulation circuit 20 for circulating water in a bath tub and heating it and a hot water feeding circuit 30 for use in connecting the hot water feeding circuit 10 to the circulation circuit 20, a first valve S1 opened when the hot water is fed, a hopper 32 capable of releasing the hot water feeding circuit 30 to the surrounding atmosphere, a second valve S2, a pressure sensor 33 and a third valve S3 are arranged in series from the hot water supplying circuit within the hot water feeding circuit. There is provided a control section 40 for opening the first, second and third valves when hot water is fed to a bath tube 43, closing the first and third valves and opening the second valve when the pressure sensor is corrected, releasing the hopper to the surrounding atmosphere and sensing an output of the pressure sensor 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined hot water supply system comprising a hot water supply circuit for heating hot water to supply hot water, a circulation circuit for circulating and heating water in a bathtub, and a pouring circuit for connecting them. The present invention relates to a configuration capable of easily correcting a pressure sensor of a vessel.

[0002]

2. Description of the Related Art A complex type water heater having a hot water supply unit and a bath tub reheating unit and a hot water supply circuit and a pouring circuit for connecting the reheating unit is provided with a pressure sensor in a circuit connected to the bath tub. There is one that detects the water level in the bathtub. On the other hand, a hopper that can open to the atmosphere is provided in the pouring circuit, and the hopper is opened to the atmosphere after pouring, so that the hot water heater and the bathtub can be placed in any vertical position. Air separation is performed between the side water and the sewage in the circulation circuit. Therefore, the position of the hopper is configured to be closer to the hot water supply circuit than the pressure sensor.

In a water heater with a pressure sensor which is widely used at present, a pressure value in a pipe is stored as a pressure value of a reference water level in a storage mode performed at the time of construction when a circulating metal fitting of a bathtub is set as a reference water level. Then, at the time of actual operation, the pressure in the piping is detected by a pressure sensor via a circulation circuit connected to the bathtub, and the current water level of the bathtub is obtained by comparing the pressure value with the reference water level.

[0004]

However, widely used pressure sensors have fluctuations in the detection values and large fluctuations in the detection values due to aging, and it is necessary to frequently correct or calibrate the detection values. There is. A general pressure sensor has a diaphragm or the like inside, and the diaphragm is deformed by the pressure applied to the diaphragm,
The degree of the deformation is output as a detection value. Therefore, in the conventional water heater, the above-described reference water level state is reproduced by a complicated pouring process during the automatic hot water filling operation, and the detection value of the pressure sensor at that time is compared with the stored output value at the reference water level. Correction and calibration. This is because, in order to perform the correction at times other than the automatic hot water filling operation, it is necessary to pouring the bath so that the bathtub has the reference water level for the correction.

FIG. 9 is a reference diagram showing the water level in the bathtub 43 in the storage mode. FIG. 10 is a reference diagram showing the water level in the bathtub 43 during the conventional automatic hot water filling operation. FIG. 11 is a flowchart thereof.

As shown in FIG. 7, immediately after the water heater and the bathtub are first installed, it is assumed that the inside of the bathtub is empty, and while pouring the water into the bathtub, the water amount Q up to the reference water level Pa is maintained.
a, the pressure sensor value at the reference water level and the bathtub area S are stored. For that purpose, it is confirmed by the water flow switch in the circulation circuit that the water level has reached the circulation fitting 44 in the bathtub, and the pouring amount up to the reference water level Pa above the circulation fitting 44 and the value of the pressure sensor are stored. Further, for example, 30 liters of water are poured and the area of the bathtub is calculated and stored from the pressure sensor value at the water level Pb and stored.

Next, the automatic hot water filling operation is started by setting a water level and a temperature from a remote controller and turning on an automatic switch as shown in a flowchart of FIG. 9 (S61). First, the circulation pump in the circulation circuit is operated (S62), and it is checked whether or not the bath water switch is off (S62).
63) If on, it is determined that there is more water remaining in the bathtub than the circulating metal fittings, and the operation shifts to reheating operation (S75). Is poured into the bathtub 47 by opening the pouring solenoid valve (S
64). Then, the circulating pump is turned on to check whether or not the water switch is off (S65, S66).
If it is on, the process proceeds to the reheating operation (S75), and if it is off, the amount of water reaching below the circulation fitting is poured (S6).
7). In the storage mode, the amount of water (10 + X liters) below the circulating metal fittings of the bathtub is stored. If the stored values are used, it is possible to know the amount of water required when the bathtub 47 is empty. Pouring of only that amount is performed.

Then, the pouring solenoid valve is closed, the circulation pump is turned on, and it is checked whether or not the bath water switch is off (S69). When the water level is higher than the circulation fitting, the water flow switch is turned on.
The operation shifts to 75), and if it is off, it is determined that the bath tub is initially empty, and the pouring solenoid valve is opened to pour the water to the reference water level A above the circulation fitting (S70). Also in this case, the value Y liter stored in the storage mode is used.

The circulation pump is turned on (S71), and after confirming that the bath water switch is on (S72), the circulation pump is stopped and the output from the pressure sensor is taken in (S73). The value of the pressure sensor detected at this time is a value corresponding to the reference water level Pa. Therefore, this detected value is compared with the sensor output value when pouring up to the reference water level above the circulating metal fitting stored in the storage mode, and if different, it means that the pressure sensor 45 has undergone aging. The water level pressure value is corrected to the new output value. Specifically, the data is rewritten to the nonvolatile memory connected to the microcomputer of the control device.

If it is determined in steps S63, 66, and 69 that there is a water level above the circulating metal fitting, the water is reheated to near the set temperature (S75). Thereafter, when the temperature rises to near the set temperature, the pressure value of the pressure sensor is detected (S76).

Thereafter, a step of pouring the molten metal to the set water level is performed according to steps S77, S78 and S79. In this pouring step, pouring is performed by opening the pouring solenoid valve, closing the pouring solenoid valve and stopping the circulation pump, and then the water level in the bathtub is detected by the pressure sensor. When it is determined that the set water level has been reached (S77), reheating is performed to the set temperature (S77).
80) Finally, a buzzer is output (S8).
1).

As described above, in order to perform correction and calibration based on aging of the pressure sensor, a small amount of water is poured and rotation of the circulation pump is performed during automatic filling operation when a filling command is received from the user. It is necessary to repeat the detection of the circulating water switch, and there is a problem that the time required for the automatic filling operation becomes long.

Accordingly, an object of the present invention is to provide a combined water heater that can easily perform correction and calibration of a pressure sensor at any time without the need to perform correction and calibration of a pressure sensor during automatic hot water filling operation. To provide.

[0014]

According to the present invention, there is provided a hot water supply circuit for heating hot water to supply hot water, a circulation circuit for circulating and heating water in a bathtub, and a hot water supply circuit. In a combined water heater having a pouring circuit for connecting a circulation circuit, a first valve which is opened in the pouring circuit in order from the side of the hot water supply circuit at the time of pouring, and the pouring circuit can be opened to the atmosphere. A hopper, a second valve, a pressure sensor, and a third valve are provided in series, and when pouring into the bath, the first, second, and third valves are opened to correct the pressure sensor. A control unit for closing the first and third valves, opening the second valve, and opening the hopper to the atmosphere to detect the output of the pressure sensor. It is achieved by doing.

Further, in the above invention, the control unit further closes the first and second valves, opens the third valve when the pouring is not performed, and outputs the pressure from the output of the pressure sensor. It is characterized by detecting the water level in the bathtub.

According to the above invention, the pressure sensor correction,
The detection of the reference value for calibration is not performed according to the reference water level of the bathtub, but is performed based on the water level when the hopper is opened to the atmosphere, so it is corrected regardless of the automatic operation of filling the bathtub , Calibration can be performed. Accordingly, the time for the automatic hot water filling operation can be shortened accordingly.

Further, according to another aspect of the present invention, there is provided:
A hot water supply circuit for heating the hot water to supply hot water, a circulation circuit for circulating and heating water in the bathtub, and a hot water supply circuit for connecting the hot water supply circuit and the circulation circuit; A first valve that is opened in the circuit at the time of pouring from the hot water supply circuit side, and a hopper that can open the pouring circuit to the atmosphere;
A second valve, a pressure sensor, and a three-way valve are provided in series, and the first and second valves are opened when pouring into the bath,
The three-way valve is set at a position where the pouring circuit and the circulation circuit are connected, and when correcting the pressure sensor, the first valve is closed and the second valve is opened, and the three-way valve is connected to the pouring circuit. This is achieved by providing a combined water heater characterized by having a control unit that sets the hopper to the atmosphere and sets the hopper to the atmosphere and detects the output of the pressure sensor.

In this configuration, similarly, the pressure sensor correction,
Calibration can be performed in a separate step from the filling operation.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to the embodiment.

FIG. 1 is a diagram showing a configuration of a water heater according to the first embodiment. It has a circulation circuit 20 connected to the hot water supply circuit 10 and the bathtub, and a pouring circuit 30 connecting them. In the hot water supply circuit 10, a heat exchanger 11, a water amount sensor 15, an incoming water temperature sensor 16, an outgoing water temperature sensor 17, a water flow switch 18, and a hot water supply port 19 are provided. When the tap of the hot water supply port 19 is opened, the water amount sensor 15 detects and opens the gas source solenoid valve 14, the opening of the proportional valve 13 is adjusted, and the burner 1 is opened.
2 are controlled. As a result, feedforward and feedback control are performed so that the tapping temperature becomes the set temperature.

In the circulation circuit 20, a heat exchanger 21, a temperature sensor 22, a circulation pump 23, and a water flow switch 24 are provided. Reference numeral 25 denotes a burner, which is connected to a gas inlet of the original gas valve 14 via an electromagnetic valve 26. The detection of whether or not there is a water level above the circulation fitting 44 in the bathtub 43 is performed by the circulation pump 2
3 is driven, and whether or not the water flow switch 24 detects flowing water is performed. The reheating operation is performed by the circulation pump 2
3 drives the burner 25 and ignites the temperature sensor 2
2 is performed by burning until the temperature reaches the set temperature.

In the pouring circuit 30, a pouring solenoid valve S1, a check valve 31, and a check valve 31, which are the first solenoid valves, are arranged in this order from the hot water supply circuit side.
Hopper 32 capable of opening and closing to atmosphere, second solenoid valve S
2. A pressure sensor 33 and a third solenoid valve S3 are provided in series. The above-described actuators such as the sensor and the solenoid valve are connected to a control unit 40 having a microcomputer by a wiring (not shown).

FIG. 2 is a table showing the open / closed state of the hopper 32 and the solenoid valves S1, S2, S3 in the pouring circuit 30 of the water heater. According to this chart, the respective operations during pouring, when pouring is not performed after pouring (pouring stop), and when the pressure sensor is corrected will be described. The opening and closing operations of the solenoid valve and the hopper are all performed by drive signals from the control unit 40.

[At the time of pouring] When a command for automatic filling is issued from a remote controller (not shown), solenoid valves S1 and S in the pouring circuit are provided.
2 and S3 are all opened, the hopper 32 is closed from the atmosphere, the hot water supply burner 12 burns, and the hot water is supplied from the hot water supply circuit 10 to the bathtub 43 via the pouring circuit 30 and the circulation circuit 20. In this automatic operation, since the control is performed without performing correction and calibration of the pressure sensor 33 based on the reference water level of the bathtub 43 as described later, the time required for the automatic operation is shorter than in the conventional example.

[When pouring is stopped] When pouring is completed, as shown in FIG. 2, the pouring solenoid valve S1 as the first solenoid valve is closed. Then, in order to separate air from the circulation circuit and the hot water supply circuit, the hopper 32 is opened to open the atmosphere. Further, the second solenoid valve S2 is closed, and the third solenoid valve S3 is opened, so that the pressure sensor 33 is connected to the bathtub via the circulation circuit 20. As a result, when pouring is not performed, the pressure sensor 33 detects the water level in the bathtub.

Further, by closing the second solenoid valve S2, even if the bathtub 43 is installed at a position lower than the position where the water heater is installed, it is possible to prevent the water in the circulation circuit 20 from being drained. Is done. Once the water in the circulation circuit 20 has escaped, it is not only impossible to detect the water level in the bathtub by the pressure sensor 33, but also it is difficult to refill the water.

[At the time of pressure sensor correction] Correction or calibration corresponding to aging of the pressure sensor 33 is performed as follows. As shown in FIG. 2, the first solenoid valve S1 and the third solenoid valve S3 are closed, and the second solenoid valve S2 is opened.
Then, the hopper 32 is opened to the atmosphere. as a result,
The pressure sensor 33 is connected to the hopper 32 via the second solenoid valve S2.
To open air. Therefore, the pressure sensor 3
3 detects the water level of the hopper 32. The detection value of the pressure sensor 33 in this state is stored as a reference value in a non-volatile memory (not shown), and the reference value is periodically compared with the detection value. That value is corrected.

Since the above state can be reproduced simply by opening and closing the solenoid valve and opening and closing the hopper 32, it can be easily performed in a process different from the automatic operation. Therefore, it can be performed periodically, for example, at midnight when combustion is not performed.

At the time of this correction, since the third solenoid valve S3 is closed, water in the circulation circuit 20 does not leak.

FIG. 3 is a diagram showing a configuration of a water heater according to a second embodiment. In this example, the hot water supply circuit 10 and the circulation circuit 20 are equivalent to those of the first embodiment. A hot water supply circuit 10 is connected to the pouring circuit 30 connecting them.
From the side, a pouring solenoid valve S1, which is a first solenoid valve, a check valve 31, a hopper 32 capable of opening to the atmosphere, and a second solenoid valve S
2, a pressure sensor 33 and a three-way valve 34 are provided.
Further, an electromagnetic valve S4 is provided ahead of the three-way valve 34. The difference from the first embodiment is that the three-way valve 3
4 and an electromagnetic valve S4.

FIG. 4 shows the solenoid valves S1, S2, S4 and the three-way valve 34 in the pouring circuit of the water heater according to the second embodiment.
6 is a table showing the open / closed state of the hopper 32. The operations at the time of pouring, when pouring is stopped, and at the time of pressure sensor correction will be described with reference to this chart.

[At the time of pouring] When a command for automatic filling is issued from a remote controller (not shown), the solenoid valves S1 and S in the pouring circuit are provided.
2 is opened, the hopper 32 is closed from the atmosphere, and the three-way valve 34 is set in the direction connecting the pouring circuit 30 and the circulation circuit 20. The solenoid valve S4 is normally closed.
Then, hot water supply burner 12 is burned and poured from hot water supply circuit 10 to bath tub 43 via pouring circuit 30 and circulation circuit 20. In this automatic operation, as will be described later, since the control is performed without performing correction and calibration of the pressure sensor 33 based on the reference water level of the bathtub 43, the time required for the automatic operation is shorter than in the conventional example.

When pouring is stopped, as shown in FIG. 4, pouring solenoid valve S1, which is the first solenoid valve, is closed. Then, in order to separate air from the circulation circuit and the hot water supply circuit, the hopper 32 is opened to open the atmosphere. Further, the second solenoid valve S2 is closed, and the three-way valve 34 is set to connect the pouring circuit 30 and the circulation circuit 20. As a result, the pressure sensor 33 is connected to the bathtub via the circulation circuit 20. As a result, when pouring is not performed, the pressure sensor 33 detects the water level in the bathtub.

Further, as in the first embodiment, by closing the second solenoid valve S2, even if the bathtub 43 is installed at a position lower than the position where the water heater is installed, the circulation circuit It is prevented that the water in 20 is leaked.

[At the time of pressure sensor correction] Correction or calibration corresponding to aging of the pressure sensor 33 is performed as follows. As shown in FIG. 4, the first solenoid valve S1 is closed, the second solenoid valve S2 is opened, and the hopper 32 is opened to the atmosphere. The three-way valve 34 is set at a position where the space between the pouring circuit 30 and the circulation circuit 20 is closed. As a result, the pressure sensor 33 is connected to the atmosphere of the hopper 32 via the second solenoid valve S2. Therefore, the pressure sensor 33 detects the water level of the hopper 32. The detection value of the pressure sensor 33 in this state is stored as a reference value in a non-volatile memory (not shown), and the reference value is periodically compared with the detection value. That value is corrected.

The above state can be reproduced simply by opening and closing the solenoid valve, setting the three-way valve, and opening and closing the hopper 32, so that it can be easily performed in a process different from the automatic operation. Therefore, it can be performed periodically, for example, at midnight when combustion is not performed.

At the time of this correction, the space between the pouring circuit and the circulation circuit is closed by the three-way valve 34, so that the water in the circulation circuit 20 does not escape.

At the time of this correction, the three-way valve 34 is connected to the pouring circuit 3
0 may be set at a position where the solenoid valve S4 is connected to the solenoid valve S4.
In this case, by opening the normally closed solenoid valve S4, the water in the pipe of the pouring circuit 30 to which the pressure sensor 33 is attached flows from the hopper 32 in the open-to-atmosphere state to the solenoid valve S4. After being discharged, the pressure sensor 33 can output a detection value in an open-to-atmosphere state. Therefore,
Correction or calibration of the pressure sensor 33 can be performed more accurately.

In the first and second embodiments described above,
Since the distance between the pressure sensor 33 and the reference water level of the hopper 32 is extremely short, the pressure value of the pressure sensor 33 with respect to the reference water level can be accurately detected. FIG.
It is a figure showing the example where water heater 1 was usually installed in the house.
As shown in this figure, it is assumed that it is obligatory to install the bathtub 43 between the height at which the water heater 1 is attached and a position higher by 5 m or lower by 3 m, for example. In that case, in the conventional method, the distance between the reference water level in the bathtub 43 and the pressure sensor 33 is extremely long as compared with the embodiment of the present invention. Therefore, it is difficult for the pressure sensor 33 to accurately detect such a difference of 1 to 2 cm at such a distant position. In this regard, in the above embodiment, since the position of the reference water level Pa is close to the same water heater, the pressure value of the reference water level can be accurately obtained.

FIG. 6 further shows the pressure sensor 33, the solenoid valve S2, the hopper 32, the check valve 31,
It is a fragmentary sectional view showing a specific example of pouring solenoid valve S1.
In this cross-sectional view, a pilot-type pouring valve S1 is provided in a pouring circuit 30, a check valve 31 that permits water flow from top to bottom by water pressure, and a drain hole is closed or opened in conjunction with the check valve 31. Hopper 32 and a direct-acting solenoid valve S2 are provided. The pilot-type pouring valve S1 forms a pressure difference through a pilot hole (center) by pulling up a plunger by an electromagnetic coil from a closed state shown in the figure,
The main valve is opened using the water pressure of the water supply. On the other hand, when the hopper 32 is open, the solenoid valve S2 is a direct-acting solenoid valve because there is no similar water pressure. Therefore, the direct-acting solenoid valve S2 is simply opened and closed by the electromagnetic coil. L in the figure is a pressure value up to the reference water level Pa detected by the pressure sensor 33.

[Automatic Filling (Pouring) Operation] As described above, in the water heater according to the embodiment of the present invention, it is not necessary to detect the reference value for correcting the pressure sensor 33 during the automatic operation. Therefore, the automatic operation can be performed in a shorter time than in the conventional example.

FIG. 7 is a reference diagram for explaining an example of the automatic hot water filling operation. FIG. 8 is a flowchart of an example of the automatic hot water filling operation. In this automatic operation, when it is first confirmed that there is no water in the circulation circuit 20, the water amount Z liter ((Ps−Pa) ×) from the reference water level Pa stored in the storage mode operation to the set water level Ps.
(S, S is the area of the bathtub) to check whether the water level has risen above the circulation fitting 44, and after confirming that the water level has risen above the circulation fitting 44, use the output value of the pressure sensor. Pouring to the set water level Ps. This pouring amount is obtained by calculation from the bathtub area S and the water level.

As shown in FIG. 8, when the automatic hot water filling operation switch is first turned on from the remote controller (S1).
0), and drives the circulation pump 23 in the circulation circuit 20 (S1).
1), it is detected whether or not the water switch 24 is turned on (S12). Then, when the flowing water switch 24 is turned on, it means that the water level in the bathtub is already higher than the circulation fitting 44, so that additional heating is performed to raise the temperature to the set temperature (S22). When the water switch 24 is off,
Although the water level is higher than the circulating metal fittings, the inside of the circulating circuit 20 may only be empty. Therefore, in Step S13, about 10 liters are poured and it is confirmed that the flowing water switch 24 is not turned on (S14, 15).

Then, after confirming that the flow switch 24 is off, the molten metal is poured by Z liters (S16). By pouring only Z liters, even if there is residual water below the circulating metal in the bathtub 43, pouring is never prevented above the set water level Ps.
Then, the circulation pump 23 is driven again to check whether or not the running water switch 24 is turned on.
Even if the position of the circulation fitting 44 is slightly moved up and down, the molten metal can be reliably poured to an arbitrary water level between the set water level Ps and the circulation fitting 44 (S17, 18).

Therefore, after the circulation pump is stopped, the output of the pressure sensor 33 is detected, and the current bathtub water level P1 is determined based on the relative relationship with the output value of the pressure sensor at the reference water level of the bathtub.
Is detected (S19). Then, the required pouring amount to the set water level is calculated and pouring is performed (S21). When pouring is performed to the set water level (S20), reheating is performed to the set temperature thereafter (S23), and finally a buzzer for terminating the filling (S24).

As described above, at the time of automatic operation of hot water filling,
It is not necessary to perform a step of setting the water level of the bathtub to the reference water level Pa as in the conventional case. Therefore, it is simply checked whether or not the circulation circuit 20 is empty, and if it is empty, replenishment of Z liters is repeated to fill the circulation circuit 20 with water. Since only hot water is required, the time required for automatic operation can be significantly reduced.

[0047]

As described above, according to the present invention, the detection of the reference output for correcting or calibrating the pressure sensor can be performed by opening the hopper to the atmosphere without using the reference water level of the bathtub. Since the reference is used, correction or calibration of the pressure sensor can be easily performed. Therefore, the time required for the automatic filling operation can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a water heater according to a first embodiment.

FIG. 2 is a table showing the open / close states of solenoid valves S1, S2, S3 and a hopper 32 in a pouring circuit 30 of the water heater of the first embodiment.

FIG. 3 is a diagram showing a configuration of a water heater according to a second embodiment.

FIG. 4 is a table showing the open / close states of solenoid valves S1, S2, S3 and a hopper 32 in a pouring circuit 30 of a water heater according to a second embodiment.

FIG. 5 is a diagram showing a state where a water heater is installed in a house.

FIG. 6 is a partial sectional view of an example of a pouring circuit according to the first and second embodiments.

FIG. 7 is a reference diagram for describing an example of an automatic filling operation.

FIG. 8 is a flowchart illustrating an example of an automatic hot water filling operation.

FIG. 9 is a reference diagram showing a water level in a bathtub 43 in a storage mode.

FIG. 10 is a reference diagram showing a water level in a bathtub 43 during a conventional automatic hot water filling operation.

FIG. 11 is a flowchart of a conventional automatic hot water filling operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hot-water supply circuit 20 Circulation circuit 30 Pouring circuit S1, S2, S3 First, second, third valve 32 Hopper 33 Pressure sensor 40 Control unit

Claims (5)

[Claims] 1. A composite water heater comprising a hot water supply circuit for heating hot water to supply hot water, a circulation circuit for circulating and heating water in a bathtub, and a pouring circuit for connecting the hot water supply circuit and the circulation circuit. In the pouring circuit, a first valve that is opened at the time of pouring from the side of the hot water supply circuit, a hopper capable of opening the pouring circuit to the atmosphere, a second valve, a pressure sensor, Are provided in series, the first, second and third valves are opened when pouring into the bath, and the first and third valves are closed when the pressure sensor is corrected. A combined type water heater comprising a control unit for opening a valve, opening the hopper to the atmosphere and detecting an output of the pressure sensor. 2. The combined water heater according to claim 1, wherein the control unit further closes the first and second valves and opens the third valve when the pouring is not performed, The water level of the bathtub is detected from the output of the pressure sensor. 3. A combined water heater having a hot water supply circuit for heating and supplying hot water, a circulation circuit for circulating and heating water in the bathtub, and a pouring circuit for connecting the hot water supply circuit and the circulation circuit. In the pouring circuit, a first valve opened at the time of pouring from the hot water supply circuit side in order, a hopper capable of opening the pouring circuit to the atmosphere, a second valve, a pressure sensor, A valve is provided in series, the first and second valves are opened at the time of pouring into the bathtub, and the three-way valve is set at a position connecting the pouring circuit and the circulation circuit; At the time of correction, the first valve is closed and the second valve is opened, the three-way valve is set at a position for separating the pouring circuit and the circulation circuit, the hopper is opened to the atmosphere, and the pressure sensor is A combined water heater comprising a control unit for detecting an output. 4. The combined water heater according to claim 3, wherein the control unit further closes the first and second valves when the pouring is not performed, and causes the three-way valve to pouring the hot water. It is set at a position where the circuit and the circulation circuit are connected, and the water level of the bathtub is detected from the output of the pressure sensor. 5. The combined water heater according to claim 3, further comprising: a third valve provided between said three-way valve and the atmosphere, wherein said control unit controls said three-way valve when correcting said pressure sensor. A valve is set at a position connecting the pouring circuit and the third valve, the third valve is opened, and the third valve is closed at the time of pouring and when pouring is not performed. And