JP2019066127A - Water heater - Google Patents

Abstract

To prevent high-temperature tapping upon starting using a hot water supply circuit, even in a case where a hot water supply amount sensor provided in the hot water supply circuit breaks down, in a water heater with one tank and two water channel where one water conduction passage serves as the hot water supply circuit.SOLUTION: A water heater is configured to: when hot water is not supplied in determination of S1, confirm whether a bath is being reheated in determination of S2; when it is confirmed that reheating is ended in determination of S3, recalculate a bypass ratio at S4, based on a formula using a setting temperature set by a hot water supply remote controller or bath remote controller, and an intake water temperature obtained from an intake water thermistor; and drive a stepping motor of a distribution valve so as to change a bypass ratio to the recalculated bypass ratio.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a so-called one-can dual-channel water heater in which two heat exchangers having different water passages are provided in one combustion chamber equipped with a burner.

A water heater connects a water supply pipe and a hot water discharge pipe to a heat exchanger heated to a burner, opens the external hot water supply tap to which the hot water discharge pipe is connected, and supplies water supplied from the water supply pipe via a water pipe. It has a hot water supply circuit which exchanges heat with the combustion exhaust of the burner and discharges hot water. In addition to this, it is also known to form a water passage connecting the heat exchanger to an external bath tub, bathroom heater, etc., and to heat it up with the heat exchanger while circulating hot and cold water to carry out reheating and heating. It is done.
In such a water heater, in addition to a configuration (two-can two-channel type) in which a tub or a heat exchanger on the heater side and a heat exchanger on the hot water supply circuit are installed in different combustion chambers and heated by different burners, As disclosed in Patent Document 1, a hot water supply heat exchanger on the hot water supply circuit side and a bath heat exchanger on the bathtub side, for example, are juxtaposed in one combustion chamber, and two heat exchangers are heated by a common burner. A single can-bichannel type configuration is also often used.

JP, 2017-155956, A

In the hot water supply circuit, a controller that controls the operation of the appliance by connecting a bypass pipe that bypasses the hot water supply heat exchanger between the water supply pipe and the hot water discharge pipe, and providing a distribution valve that controls the flow rate from the bypass pipe By monitoring the outlet temperature from the combustion chamber to the outlet tube in passing water and adjusting the degree of opening of the distribution valve, the outlet temperature is maintained within the temperature range that can prevent the occurrence of drainage and overheating in the heat exchanger. Control the flow rate to the bypass pipe (bypass rate).
However, in the case of a one-can two-channel water heater, for example, in the case where a hot water supply circuit and a bath circuit are provided side by side, it is not used and used when using only the bath circuit Since the hot water supply heat exchanger which is not heated is also heated by the burner, there is a possibility that the water staying in the hot water supply heat exchanger may become high temperature.
Even if the hot water supply plug is opened in this state, the controller operates the distribution valve when the water flow is detected by the hot water supply amount sensor provided in the water supply pipe, so that the water from the bypass pipe is mixed, Hot water can be prevented. However, if the hot water supply valve is opened in a state where the hot water supply amount sensor is broken, the controller does not detect the flow of water and the distribution valve is not operated, which may cause hot water to be discharged.

  Therefore, in the present invention, even in the case where the hot water supply amount sensor provided in the hot water supply circuit breaks down in the one-can two water channel type in which one water flow path becomes the hot water supply circuit, high temperature hot water at the start of using the hot water supply circuit. It is an object of the present invention to provide a water heater that can be prevented.

In order to achieve the above object, the invention according to claim 1 is a combustion chamber in which a burner is disposed at the lower part,
A hot water supply heat exchanger disposed at the top of the combustion chamber, a water supply pipe and a hot water discharge pipe connected to the hot water supply heat exchanger, and a bypass pipe connected between the water supply pipe and the hot water discharge pipe to bypass the hot water supply heat exchanger And a hot water supply circuit comprising: bypass flow rate control means for controlling the amount of water flow to the bypass pipe;
A heat exchanger which is juxtaposed with a hot water supply heat exchanger in the upper part of the combustion chamber and to which a water flow path different from the hot water supply circuit is connected, water temperature detection means for detecting the water temperature into the water supply pipe, and Temperature setting means for setting a water flow detection means for detecting water flow to the hot water supply circuit;
When the water flow is detected by the water flow detection means, the combustion of the burner is controlled according to the set temperature set by the temperature setting means, and the bypass flow rate control means is controlled to flow the bypass pipe for the water flow rate of the entire hot water supply circuit. And a controller for adjusting a bypass rate, which is a rate of water volume, comprising:
The controller changes the bypass ratio based on the incoming water temperature obtained from the incoming water temperature detection means and the set temperature set by the temperature setting means at a predetermined timing before reuse after the use of the hot water supply circuit is completed, It is characterized in that the bypass flow rate control means is controlled so as to obtain the changed bypass rate.
The invention according to claim 2 is that, in the configuration according to claim 1, the water passage is a bath circuit connecting the heat exchanger to an external bathtub, and the predetermined timing is a bathtub by single use of the bath circuit. It is characterized in that it is a case where retiring is finished.
The invention according to claim 3 is characterized in that, in the configuration according to claim 1 or 2, the predetermined timing is a case where the set temperature is changed by the temperature setting means.

According to the invention as set forth in claim 1, the controller changes the bypass ratio based on the incoming water temperature and the set temperature at a predetermined timing after reuse of the hot water supply circuit and before reuse, and the changed bypass ratio Since the bypass flow rate control means is controlled to be as above, even if water flow can not be detected due to a failure of the water flow detection means when the hot water supply circuit is reused, Water from the bypass pipe is always mixed. Therefore, in the one-can-bichannel type in which one water flow path is a hot water supply circuit, even if the water flow detection means provided in the hot water supply circuit fails, high temperature hot water is prevented at the start of using the hot water supply circuit. Can.
According to the invention of claim 2, in addition to the effect of claim 1, the timing of the change of the bypass rate is a case where the retiring of the bathtub by the single use of the bath circuit is finished, so that the bath circuit alone Even when the water staying in the hot water supply heat exchanger which is not used at the time of use is heated and becomes high temperature, high temperature hot water from the hot water discharge pipe can be surely prevented when using the hot water supply circuit.
According to the third aspect of the invention, in addition to the effect of the first or second aspect, the timing of changing the bypass ratio is the same as when the set temperature is changed by the temperature setting means. It is possible to change the combined bypass rate appropriately.

It is a schematic circuit diagram of a water heater. It is a flowchart of bypass ratio change control.

Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 1 is a schematic circuit diagram showing an example of a water heater. This water heater 1 supplies combustion air to each burner unit 3 and three burner units 3, 3... Provided with a plurality of burners 4, 4. A combustion fan 5 is provided, and a hot water supply heat exchanger 6 and a bath heat exchanger 7 through which the combustion exhausts of the burners 4, 4... Pass at an upper portion in the combustion chamber 2. 8 is a spark plug, 9 is a flame rod, and an exhaust hood 10 for exhausting the combustion exhaust gas passing through both heat exchangers 6, 7 is provided at the upper part of the combustion chamber 2. A sheet-like overheat protection device 11 printed with a fuse circuit for detecting leakage of combustion exhaust gas from the chamber 2 is wound.

  A gas pipe 12 to which a gas pipe from the outside is connected is connected to a gas inlet of a device accommodating the combustion chamber 2 and the like, and each burner unit 3 is connected to branch pipes 13, 13 · · · branched from the gas pipe 12 Are connected to each other, and each branch pipe 13 is provided with a gas solenoid valve 14 for opening and closing a gas flow path. In addition, a source gas solenoid valve 15 and a gas proportional valve 16 are provided on the upstream side of the gas pipe 12 before branching.

The hot water supply heat exchanger 6 includes a hot water supply heat transfer pipe 18 penetrating the plurality of fins 17, 17 ··· arranged at a predetermined interval in a serpentine manner, and the inlet of the hot water supply heat transfer pipe 18 is a water inlet of an appliance. The water supply pipe 19 connected to is connected, and the outlet pipe 20 connected to the hot water outlet of the appliance is connected to the outlet of the hot water supply heat transfer pipe 18. A water pipe thermistor 21 for detecting the temperature of the hot water supply heat transfer pipe 18 is provided at a bent portion of the hot water supply heat transfer pipe 18 exposed to the outside of the hot water supply heat exchanger 6. Further, a bypass pipe 22 bypassing the hot water supply heat exchanger 6 is connected between the water supply pipe 19 and the hot water discharge pipe 20, and a connection portion between the water supply pipe 19 and the bypass pipe 22 is driven by a stepping motor. A distribution valve 23 for variably controlling the flow rate of the bypass pipe 22 is provided.
There is.

Further, on the upstream side of the connection portion of the water supply pipe 19 with the bypass pipe 22, a water inlet thermistor 24 for detecting the temperature of the incoming water and a hot water supply sensor 25 for detecting the amount of water flowing through the water supply pipe 19 are provided.
Then, at the outlet of the hot water supply heat exchanger 6 in the hot water discharge pipe 20, a hot water supply heat exchanger thermistor 26 for detecting the outlet temperature is provided, and the hot water discharge temperature is detected downstream of the connection portion with the bypass pipe 22 A hot water supply hot water discharge thermistor 27 and a water amount control valve 28 which is driven by a stepping motor to variably control the flow rate of the hot water discharge pipe 20 are provided.
Therefore, the hot water supply heat exchanger 6 heated by the burner unit 3 and the hot water supply circuit 19 including the water supply pipe 19 and the hot water discharge pipe 20 connected to the hot water supply heat exchanger 6 and the bypass pipe 22 are formed here.

On the other hand, the bath heat exchanger 7 includes a bath heat transfer pipe 30 penetrating the fins 17 17 in a meandering manner, and the bath adapter 32 of the external bath 31 at the inlet of the bath heat transfer pipe 30 via external piping. The bath return pipe 33 connected is connected to the outlet of the bath heat transfer pipe 30, and the bath return pipe 34 connected to the bath adapter 32 via an external pipe is connected. A pump 35 is provided in the bath return pipe 33, and a bath return thermistor 36 for detecting a bath return temperature is provided on the upstream side thereof, and a hot water in the bath return pipe 33 is provided on the downstream side of the pump 35. A bath water flow switch 37 which is turned ON / OFF by the flow, and a water level sensor 38 which detects the water level in the bathtub 31 by water pressure are provided. Further, a bath-tripping thermistor 34 is provided in the bath-passing pipe 34 for detecting the bath-passing temperature.
Therefore, a bath circuit B including a bath heat exchanger 7 to be heated by the burner unit 3 and a bath return pipe 33 and a bath forward pipe 34 connected between the bath heat exchanger 7 and the bath 31 are provided here. Is formed.
As described above, the water heater 1 is heated by the common burner units 3, 3 ··· with the hot water supply heat exchanger 6 and the bath heat exchanger 7 which are different in water passage in one combustion chamber 2 side by side It is one can and two channels type.

Then, between the hot water supply circuit A and the bath circuit B, a drop pipe 41 is connected between the pump 35 and the bath return thermistor 36 in the bath return pipe 33 on the downstream side of the water quantity control valve 28 in the hot water pipe 20 There is. A bath water amount sensor 42 for detecting the amount of water flowing through the dropping pipe 41 is provided on the upstream side of the dropping pipe 41, and a dropping water solenoid valve 43 for opening and closing the dropping pipe 41 is provided on the downstream side. Furthermore, two check valves 44, 44 are provided on the downstream side of the dropping water solenoid valve 43, respectively, and between the check valves 44, 44, the hot and cold water flowing back from the bath return pipe 33 is A discharge valve 45 is connected.
Reference numeral 50 denotes a controller, which includes a drive circuit for each motor, a detection circuit for each thermistor and sensor, etc. in addition to a microcomputer and memory, receives detection signals from each thermistor and sensor, and operates each valve etc. Water filling control to the bathtub 31 is performed. 51 is a hot water supply remote control, 52 is a bath remote control.

In the water heater 1 configured as described above, first, normal hot water supply is performed as follows.
The hot water supply tap of the external piping connected to the hot water outlet is opened and water flows in the device, and when the water flow is detected by the hot water supply amount sensor 25, the controller 50 rotates the combustion fan 5 for a predetermined time to burn The combustion exhaust stored in the chamber 2 is discharged (prepurge). Thereafter, the source gas solenoid valve 15 of the gas pipe 12 and each gas solenoid valve 14 are opened, the gas proportional valve 16 is opened at a predetermined opening degree, gas is supplied to each burner unit 3, and the igniter is operated. The burner 4, 4,... Is ignited by the spark plug 8.
Thereby, in the hot water supply heat exchanger 6, the water flowing through the hot water supply heat transfer pipe 18 is heat-exchanged with the combustion exhaust of the burner 4, and the heated hot water is discharged from the hot water supply tap through the hot water discharge pipe 20 and the external piping.

The controller 50 monitors the outlet temperature by the hot water supply heat exchanger thermistor 26 of the hot water discharge pipe 20, and drives the stepping motor of the distribution valve 23, and the outlet temperature prevents the generation and overheating of the drain in the hot water supply heat exchanger 6. The flow rate (bypass rate) to the bypass pipe 22 is controlled so as to be maintained within the possible temperature range.
The controller 50 monitors the hot water temperature by the hot water discharge thermistor 27 and controls the opening and closing control of each gas solenoid valve 14 so that the hot water temperature becomes the set temperature set by the hot water supply remote control 51 or the bath remote control 52. While adjusting the opening degree of the valve 16, the air amount is continuously changed by controlling the rotational speed of the combustion fan 5.
When the hot water supply plug is closed, the controller 50 that has confirmed the stop of the signal from the hot water supply amount sensor 25 closes the original gas solenoid valve 15 and the gas solenoid valve 14 to extinguish the burner 4 and rotates the combustion fan 5 for a predetermined time (post purge).

On the other hand, when the automatic switch of the hot water supply remote control 51 or the bath remote control 52 is pressed, the controller 50 opens the drop water electromagnetic valve 43 of the drop pipe 41 to cause the hot water supply heat exchanger 6 to flow water to burn the burner 4. The hot water from the hot water discharge pipe 20 is supplied to the bathtub 31 through the drop-in pipe 41, the bath return pipe 33, and the bath return pipe 34. When the amount of water detected by the bath water amount sensor 42 provided in the dropping pipe 41 reaches the set amount of water, the dropping water solenoid valve 43 is closed to complete the dropping.
Next, the pump 35 is operated to circulate hot water between the bath heat exchanger 7 and the bath 31. Therefore, the bath circulating water circulating between the bath heat exchanger 7 and the bath 31 is subjected to heat exchange with the combustion exhaust of the burner 4 when flowing through the bath heat transfer pipe 30, and is driven to the set temperature. When the set temperature is reached, the combustion of the burner 4 is stopped and the pump 35 is stopped. Further, by operating the reheating switch of the bath remote control 52, reheating can be performed at any timing.

Then, the controller 50 controls the amount of hot water supply sensor at the timing when the reheating of the bath is finished and at the timing when the set temperature is changed by the hot water remote control 51 or the bath remote 52 before the reuse of the hot water supply circuit A before the reuse. It is possible to execute bypass ratio change control that drives the stepping motor of the distribution valve 23 to change the bypass ratio so that high temperature hot water is not discharged even if the hot water supply valve is opened in a state where 25 is broken. Hereinafter, this bypass ratio change control will be described based on the flowchart of FIG.
First, it is confirmed in the determination of S1 whether or not the hot water supply is in progress, and if it is not in the hot water supply, it is confirmed in the determination of S2 whether or not the bath is being reheated. If reheating is being confirmed, the end of reheating is confirmed by the determination of S3, and if the reheating end is confirmed here, the bypass rate is set to the set temperature Ts and the incoming water temperature Ti obtained from the incoming water thermistor 24 in S4. The recalculation is performed on the basis of the following equation (1) using the equation (1), and the stepping motor of the distribution valve 23 is driven to change the bypass ratio so as to obtain the recalculated bypass ratio.

According to this equation (1), if the incoming water temperature is 0 ° C. to 20 ° C. and the set temperature is 40 ° C. to 50 ° C., the bypass rate is determined with a value of 50% to 60%.
Next, in S5, it is determined whether or not the set temperature has been changed by the remote control 51, 52, and if there is no change in the set temperature, this control is ended. Here, when it is confirmed that the set temperature has been changed, the process returns to S4, and the bypass ratio is recalculated based on the changed set temperature Ts.
On the other hand, if it is determined that the setting temperature is not being changed in S2, the change in the set temperature is determined in S5. If there is a change in the set temperature, the bypass ratio is recalculated in S4.

Thus, when the hot water supply valve is opened and water flows through the hot water supply circuit A after changing the bypass ratio at the timing when the reheating is finished and the timing when the set temperature is changed, the hot water supply sensor 25 breaks down and the controller Even if 50 does not detect water flow, the changed bypass rate is maintained, so the hot water from the hot water discharge pipe 20 is mixed with the water from the bypass pipe 22.
Therefore, even if the water in the hot water supply heat exchanger 6 is at a high temperature, the hot water will not be discharged because the bath circuit B is used alone.

  As described above, according to the water heater 1 of the above embodiment, the controller 50 controls the temperature of the incoming water temperature obtained from the incoming water thermistor 24 and the hot water remote control 51 at a predetermined timing before reuse after the use of the hot water supply circuit A ends. The hot water supply amount sensor 25 is changed when the hot water supply circuit A is reused by changing the bypass rate based on the set temperature set by the bath remote control 52 and controlling the distribution valve 23 so as to obtain the changed bypass rate. Even if water flow can not be detected due to a failure, the water from the bypass pipe 22 is always mixed with the hot water from the hot water outlet pipe 20 due to the changed bypass rate. Therefore, even in the case where the hot water supply amount sensor 25 provided in the hot water supply circuit A fails in the one-can two water flow path type in which one water passage is the hot water supply circuit A, high temperature hot water at the start of using the hot water supply circuit A It can be prevented.

Especially in this case, the timing of changing the bypass ratio is the case where the retiring of the bath tub 31 by the single use of the bath circuit B is finished, so the hot water supply heat exchanger 6 not used in the single use of the bath circuit B. Even when the water stagnating due to heating becomes high temperature, high temperature tapping from the hot water outlet pipe 20 can be reliably prevented when using the hot water supply circuit A.
Further, since the timing of changing the bypass rate is also changed when the set temperature is changed by the hot water supply remote control 51 or the bath remote control 52, it is possible to change the bypass rate appropriately according to the set temperature.

Note that the equation for changing the bypass ratio is not limited to the above embodiment, and can be changed as appropriate, such as increasing or decreasing the 10 ° C. value to be added to the set temperature, omitting the addition itself.
Moreover, as long as the configuration of the water heater itself is one-can-bichannel type, each heat exchanger may be equipped with a secondary heat exchanger for recovering latent heat. The present invention is applicable to the water flow path on the side other than the hot water supply circuit, not limited to the bath circuit, but may be a heating circuit connected to an external floor heater, a bathroom heater or the like.

  1 · · Water heater, 2 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · combustion fan, 5 · · hot water heat exchanger, 7 · · bath heat exchanger, 12 · · gas pipe · · · · · · · · · · · Hot water heat transfer pipe, 19 · · water supply pipe, 20 · · hot water discharge pipe, 21 · · water pipe thermistor, 22 · · bypass pipe, 23 · · distribution valve (by-pass flow control means), 24 · · incoming water thermistor ( Inlet temperature detection means), 25 · · Hot water supply amount sensor (water flow detection means), 27 · · Hot water supply hot water thermistor, 28 · · Water amount control valve, 30 · · Bath heat transfer tube, 31 · · · Bath, 33 · · bath return Tube, 34 · · · bathing pipe, 37 · · bath water flow switch, 41 · · dropping pipe, 50 · · controller, 51 · · hot water remote control (temperature setting means), 52 · · bath remote control (temperature setting means), A · · Hot water supply circuit, B · · bath circuit (water flow path .

Claims (3)

A combustion chamber in which a burner is disposed at the bottom,
The hot water supply heat exchanger disposed in the upper part of the combustion chamber, the water supply pipe and the hot water discharge pipe connected to the hot water supply heat exchanger, and the hot water supply heat exchanger connected between the water supply pipe and the hot water discharge pipe A hot water supply circuit comprising: a bypass pipe for bypassing the flow path; and bypass flow rate control means for controlling the amount of water flow to the bypass pipe;
A heat exchanger which is juxtaposed to the hot water supply heat exchanger at the upper part of the combustion chamber and to which a water flow path different from the hot water supply circuit is connected;
Incoming water temperature detection means for detecting the temperature of incoming water to the water supply pipe;
Temperature setting means for setting a temperature to be tapped from the tapping pipe;
Water flow detection means for detecting water flow to the hot water supply circuit;
When the water flow is detected by the water flow detection means, the combustion of the burner is controlled according to the set temperature set by the temperature setting means, and the bypass flow rate control means is controlled to control the water flow rate of the entire hot water supply circuit. A controller for adjusting a bypass ratio, which is a ratio of the flow rate of the bypass pipe to the water flow rate,
The controller is configured to set the incoming water temperature obtained from the incoming water temperature detection means and the set temperature set by the temperature setting means at a predetermined timing before reuse after the use of the hot water supply circuit ends. A water heater, wherein the bypass rate is changed based on the control and the bypass flow rate control means is controlled to be the changed bypass rate.   The water flow path is a bath circuit connecting the heat exchanger to an external bathtub, and the predetermined timing is a case where the bathtub is completely drained by using the bath circuit alone. The water heater according to claim 1.   The water heater according to claim 1, wherein the predetermined timing is when the set temperature is changed by the temperature setting unit.

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