JP3098730B2 - 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 heat exchanger for heating water supplied from an outlet channel by heating water supplied through an inlet channel by burning a burner, and detecting the flow of water to the heat exchanger. And a combustion state switching means for switching between a combustion state in which fuel is supplied to the burner to burn and a non-combustion state in which fuel supply is stopped to stop combustion. When a water flow signal is generated from the water flow signal generation means, a combustion command to make the combustion state switching means in a combustion state is issued, and when the water flow signal from the water flow signal generation means is stopped, Burner control means for executing a normal combustion control for instructing a combustion stop command for setting the combustion state switching means to a non-combustion state; and when a water passage signal is generated from the water passage signal generation means, the combustion state switching means Combustion permit to burn And a switching operation circuit for instructing a combustion non-permission command to set the combustion state switching unit to a non-combustion state when the water transmission signal from the water passage signal generation unit is stopped. The present invention relates to a hot water supply device wherein the state switching means is configured to switch to the combustion state only when both the combustion command and the combustion permission command are issued.

[0002]

2. Description of the Related Art In a hot water supply apparatus having the above-described structure, a combustion state switching means for switching a burner between a combustion state and a non-combustion state is provided by a burner control means based on a water flow signal from a water flow signal generation means. The burner does not burn in a state where there is no water flow to the heat exchanger because the command is switched to the combustion state by both the command and the combustion permission command from the switching operation circuit based on the water flow signal. Safety measures are in place. Furthermore, even if the burner control means malfunctions and there is no water flow signal from the water flow signal generation means, even if a combustion command is issued to the combustion state switching means, the combustion operation from the switching operation circuit is performed. The burner is not burned by the non-permission command, and therefore safety measures are taken against malfunction of the burner control means.

[0003] The hot water supply apparatus having such a configuration is conventionally known, but as described above, the burner is burned only when water flow to the heat exchanger is detected and a water flow signal is generated. Thus, the following problems are encountered.

[0004]

In other words, when the tapping is started by executing the normal combustion control, and then after the tapping is stopped, the time until the normal combustion control is executed again and the tapping is started becomes longer, so that the burner becomes inoperable. As a result, the temperature of the heat exchanger that has been heated decreases, and the temperature of the hot water in the heat exchanger drops to a temperature close to the temperature of the supply water. Therefore, when hot water is started again, there is a problem that low-temperature hot water in the heat exchanger is discharged immediately, and it takes a long time until hot water having a desired temperature has risen due to burner combustion.

The present invention focuses on such a conventional problem. The purpose of the present invention is to stop the flow of water to the heat exchanger while making the most of the structure provided in the conventional hot water supply apparatus. It is an object of the present invention to provide a hot water supply apparatus that can burn a burner to keep hot water in a heat exchanger even in a state, and supply hot water having a temperature close to a desired temperature at the time of returning hot water.

[0006]

According to the first aspect of the present invention, there is provided a water heating system for heating water supplied through an inlet channel by burning a burner and discharging the hot water from an outlet channel. A heat exchanger, water flow signal generating means for detecting water flow to the heat exchanger and generating a water flow signal, and stopping the combustion state and fuel supply by supplying fuel to the burner and burning. Combustion state switching means for switching to a non-combustion state in which the combustion state is stopped, and when a water flow signal is generated from the water flow signal generation means, a combustion command for setting the combustion state switching means to a combustion state is issued, Burner control means for executing normal combustion control for instructing a combustion stop command for setting the combustion state switching means to a non-combustion state when the water flow signal from the water flow signal generation means is stopped, and the water flow signal generation means A water signal is generated Commanding a combustion permission command for setting the combustion state switching means to the combustion state, and disabling the combustion for setting the combustion state switching means to the non-combustion state when the water flow signal from the water flow signal generation means is stopped. A switching operation circuit for issuing a command, wherein the combustion state switching means is configured to switch to the combustion state only when both the combustion command and the combustion permission command are issued. The burner control means, in a state where the flow of water to the heat exchanger is stopped, when the set condition for the start of warming combustion is satisfied, instructs the combustion command, and the switching operation The circuit is configured to execute a warm-up combustion control for instructing a state in which a combustion permission instruction is instructed, or a pseudo instruction for making the state equivalent thereto.

[0007] Therefore, in a state where the tapping of hot water by the normal combustion control is stopped and the flow of water to the heat exchanger is stopped, the setting conditions for the start of warming combustion, for example, the hot water inside the heat exchanger or the tapping path, etc. The temperature of hot water in the heat exchanger or the like has dropped, as in the case where the temperature of the hot water in the road has dropped or the time for which the temperature of the heat exchanger has dropped since the stop of tapping has elapsed. Is satisfied, the burner control means instructs the combustion state switching means to perform a combustion command even if the flow of water to the heat exchanger is stopped, and performs the switching operation. The heat exchanger is heated by executing the warming combustion control in which the circuit issues a combustion permission command or a pseudo command for providing a state equivalent to the command. As a result, while keeping the configuration for safety measures against idling or malfunction of the burner control means at the time of normal combustion control as described above as much as possible, it is possible to perform warm combustion while water flow to the heat exchanger is stopped. When hot water is supplied, hot water can be supplied at a temperature as close as possible to the desired temperature, and hot water at a desired temperature can be supplied in a short time.

According to the second aspect of the present invention, when the burner control means satisfies the set condition for starting the warming combustion, the burner control means sends the pseudo signal corresponding to the water flow signal to the switching operation circuit. A switching operation for instructing a combustion permission command to set the combustion state switching means to the combustion state based on the water flow signal from the water flow signal generation means during normal combustion control. By using the circuit as it is, also during the warming combustion control, the warming combustion control can be executed with the combustion state switching means in the burning state.

According to the third aspect of the present invention, the burner control means stops the command of the pseudo command and stops the command of the combustion command when the set condition for stopping the warming combustion is satisfied. Therefore, for example, the hot water temperature in a hot water path such as the inside of a heat exchanger or a hot water path becomes equal to or higher than a set upper limit value, or the set time has elapsed since the start of the insulated combustion. In such a case, when the condition that the temperature of the hot water in the heat exchanger or the like can be regarded as rising to a temperature close to the desired temperature is satisfied, the pseudo command is stopped and the burner is stopped. Combustion can be stopped. Therefore, in a state where the flow of water to the heat exchanger is stopped, it is possible to execute the heat retention combustion control for maintaining the temperature of the hot water in the hot water path of the heat exchanger or the like as close to the desired temperature as possible. Sometimes, hot water with a temperature close to the desired temperature can be supplied as quickly as possible.

According to the fourth aspect of the present invention, there is provided a hot water temperature detecting means for detecting a temperature of hot or cold water in the hot water path or the heat exchanger, and the burner control means detects the hot water temperature by the hot water temperature detecting means. When the value is equal to or less than the set lower limit value, it is configured to determine that the set condition for the start of warming combustion is satisfied, so that tapping is stopped, the temperature of the heat exchanger is reduced, and Or, when the temperature of the hot water in the heat exchanger drops below the set lower limit, combustion of the burner in the heat retention combustion control is started, and the hot water in the hot water path or the heat exchanger that flows first at the time of re-starting hot water is lower than the set lower limit. The temperature can be as low as possible, and the tapping can be started at a temperature as close as possible to the desired temperature.

According to the fifth aspect of the present invention, when the detected value of the hot water temperature detecting means is equal to or more than a set upper limit, the burner control means determines that the set condition for stopping the warming combustion is satisfied. Since it is configured to determine, when the detection value of the hot water temperature detection means is equal to or more than the set upper limit,
The combustion of the burner will be stopped, and the temperature of the hot water flowing first at the time of re-hot water will surely be prevented from rising to an unnecessarily high temperature exceeding the set upper limit value. Can be supplied with hot water.

According to the invention described in claim 6, the burner control means satisfies the set condition for stopping the warm combustion when a set time has elapsed from the start of combustion of the burner in the warm combustion control. When the set time elapses, the combustion of the burner is stopped, so that the combustion continues for a long time and the temperature of the hot water becomes higher than the desired temperature. As a result, at the start of tapping, it is possible to suppress the temporary tapping of hot water and to supply tap water at a temperature close to the desired temperature as quickly as possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water heater according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the hot water supply apparatus includes a hot water supply unit K for heating supplied water to supply hot water to a hot water tap (not shown), and a control unit H as burner control means for controlling the operation of the hot water supply unit K. And a remote control operation unit R for instructing the control unit H to give operation information.

The hot water supply section K has a combustion chamber 1.
In the combustion chamber 1, a heat exchanger 2 for water heating and a gas combustion type burner 3 for heating the heat exchanger 2 are provided.
Further, a fan 4 is provided which allows the combustion air to flow through the burner 3 and allows the air flow to be changed and adjusted. The heat exchanger 2 is connected to a water inlet channel 5 to which water is supplied from, for example, a household water supply, and a hot water outlet channel 6 for discharging hot water to a hot water tap. A water flow rate sensor 7 for detecting water flow to the exchanger 2 and an incoming water temperature thermistor 8 for detecting incoming water temperature are provided. The tap water path 6 is provided with a tap water temperature thermistor 9 for detecting tap water temperature. .

A fuel supply passage 10 for the burner 3 includes an electromagnetically operated safety valve 11 for switching between a fuel supply state for supplying fuel to the burner 3 and a non-fuel supply state for not supplying fuel, and a fuel supply path to the burner 3. Supply amount (burner 3
And an igniter 13 for performing an ignition operation on the burner 3 and detecting whether or not the burner 3 is ignited, near the burner 3. A frame rod 14 is provided.

The remote controller R includes an operation switch 15 for instructing start / stop of the operation of the hot water supply unit K, a temperature setting switch 16 as target temperature setting means for changing and setting a target temperature for tapping, a tapping temperature and a target. Display section 17 for displaying temperature and the like, operation lamp 1 for indicating that the apparatus is in the operating state
8, a combustion lamp 19 for indicating that the burner 3 is in a combustion state, and the like.

The control section H includes a microcomputer, and includes a normal combustion control means 100 for executing normal combustion control during hot water supply, and a warm combustion control means 101 for executing warm combustion control during hot water supply standby. It is provided in the form of a control program. Further, the heat-retention combustion control means 101 includes a heat-retention control restraint means 102 for restraining the execution of the heat-retention combustion control.

The normal combustion control means 100 includes a hot water supply section K
Is set to the operating state, the combustion of the burner 3 is started as the water flow to the heat exchanger 2 is started, and the burner is started as the water flow to the heat exchanger 2 is stopped. Normal combustion control for controlling the combustion of the burner 3 so as to stop the combustion of the burner 3 and, when water flow to the heat exchanger 2 is detected, adjust the combustion amount of the burner 3 so that the temperature of the hot water reaches the target temperature for hot water. Is configured to execute.

Specifically, in the normal combustion control,
The control unit H performs the following control operation. That is, the hot water supply unit K is set to the operation state in accordance with the ON operation of the operation switch 15, and in this operation state, the water flow detected by the water flow sensor 7 in response to the opening operation of the hot water tap corresponds to the set water flow. When the water passing state to the heat exchanger 2 is detected, the ventilation operation by the fan 4 is started, and the safety valve 11 is opened so that the main valve 12 is opened to the ignition gas amount. In addition to the adjustment, a spark is generated by the igniter 13 and the ignition operation for the burner 3 is started.
When the ignition state is detected by the flame rod 14, the ignition operation by the igniter 13 ends.

The tap water temperature is set to the target temperature based on the detection information of each of the incoming water temperature thermistor 8, the tap water temperature thermistor 9, and the flow rate sensor 7 and the information of the target temperature set by the temperature setting switch 16. The required combustion amount of the burner 3 is calculated by calculation, and the main valve 12 is adjusted and controlled so as to have a gas amount corresponding to the calculated combustion amount. Then, the fan 4 is controlled so as to be in a proper combustion state, and the hot water of the target temperature is controlled to be supplied from the hot water outlet path 6.

The combustion control of the burner 3 in the normal combustion is executed by the configuration shown in the control circuit block diagram of FIG. That is, when the flow rate sensor 7 detects flow of water in the hot water path and the flow rate exceeds the set flow rate, a flow rate signal (pulse signal) having the number of pulses corresponding to the flow rate is output from the flow rate detection circuit C1. The output signal is input to a transistor drive circuit C2 as a switching operation circuit for turning on the first transistor T1, and the number of input pulses is set to a normal combustion start set value (for example, when the flow rate is 2.
When the number of pulses exceeds 5 liters / minute), the first transistor T1 is turned on, and the first transistor T1 is not turned on unless the water flow signal is received.

The water flow signal is also input to the microcomputer constituting the control unit H, and the fifth transistor T5 in the figure is turned on by a command signal from the microcomputer based on the input. Then, the igniter operation relay D3 is turned on, and the second transistor T2 for driving the safety valve operation relay D1 is also turned on. This is a safety device for preventing the safety valve 11 from inadvertently operating when no drive signal is given to the igniter operation relay D3. Then, the third and fourth transistors T3 and T4 are supplied by a command signal from the microcomputer based on the input of the water flow signal.
Is also turned on, and power is supplied to the safety valve operation relay D1 and the main valve operation relay D2, respectively. As a result, in the operating electric circuit shown in FIG. 6, the third relay contact (corresponding to the igniter operating relay D3) d3, the first relay contact (corresponding to the safety valve operating relay D1) d1.
Second relay contact (corresponds to main valve actuation relay D2) d
2 is turned on to start normal combustion.

That is, the water flow rate sensor 7 and the water flow rate detection circuit C1 constitute water flow signal generation means S1 for detecting water flow to the heat exchanger 2 and generating a water flow signal. Five transistors T2, T3, T4, T5, first to third relay contacts d1, d2, d which are turned on based on ON operations of these second to fifth transistors T2, T3, T4, T5.
3, and these first to third relay contacts d1, d
Safety valve 1 operated with ON operation of d2 and d3
1. a combustion state in which the main valve 12, the igniter 13 and the like supply fuel to the burner 3 and burn the burner 3;
Combustion state switching means S2 for switching to a non-combustion state in which fuel supply to the burner 3 is stopped and combustion is stopped is constituted. When a water passage signal is generated from the water passage signal generation means S1, the control unit is controlled. The microcomputer in the figure constituting H instructs a combustion command to make the combustion state switching means S2 a combustion state,
When the water flow signal from the water flow signal generation means S2 is stopped,
The control unit H executes the normal combustion control by instructing a combustion stop command to set the combustion state switching means S2 to the non-combustion state.

Further, the transistor driving circuit C2 comprises:
When a water flow signal is generated from the water flow signal generation means S1, a combustion permission command for setting the combustion state switching means S2 to a combustion state is issued, and when the water flow signal is stopped from the water flow signal generation means S1, The combustion state switching means S2 functions as a switching operation circuit for instructing a combustion non-permission command for setting the combustion state switching means S2 to a non-combustion state.
Only when both the combustion permission command from the microcomputer and the combustion command from the microcomputer are received, the combustion state can be switched.

In the standby state in which hot water supply is stopped, that is, in a state in which the flow of water to the heat exchanger 2 is stopped, if the set condition for starting the warm combustion is satisfied, the warm-burn control means 101 burns. The combustion of the burner 3 is started when the combustion condition of the burner 3 is started, and the combustion condition of the burner 3 is stopped when the set condition for stopping the warm combustion is satisfied. More specifically, a hot water temperature thermistor 20 is provided as hot water temperature detecting means for detecting the temperature of hot water in the heat exchanger 2. If the detected value of the hot water temperature thermistor 20 is equal to or less than the set lower limit in a state where the water is stopped, it is determined that the set condition for starting the warm combustion is satisfied, and the combustion state switching means S2 is determined. Command the combustion command, whether the detected value of the hot water temperature thermistor 20 for warming exceeds the set upper limit,
Alternatively, if it is determined that there is no hot water in the hot water supply device, it is determined that the set condition for stopping the warming combustion is satisfied, and the combustion state switching means S2 is set to the non-combustion state with respect to the combustion switching means S2. It is configured to instruct a combustion stop command to make the state. In order to determine that there is no hot or cold water inside the hot water supply apparatus, the water temperature thermistor 8 is heated by itself, and the presence or absence of hot water is determined based on the cooling efficiency at that time.

The hot water temperature thermistor 20 is provided at a location in the hot water passage in the heat exchanger 2 where the hot water is liable to be heated by the combustion of the burner 3 and the hot water temperature is liable to drop during standby of hot water supply. I have. That is, as shown in FIGS. 2 to 4, the heat exchanger 2 is configured such that a plurality of fin tube type heat exchange pipe sections 2 a are vertically stacked, and the left and right side walls 1 A, 1B, and are connected to each other by a plurality of U-shaped pipes 2b on the outer sides of the left and right side walls 1A and 1B so that they form a series of pipes connected in a meandering manner. ing. Then, the heat exchange pipe portion 2 located on the lower side thereof
The hot water temperature thermistor 20 is provided in the U-shaped tube 2b located near "a".

In the initial stage of the installation of the apparatus, after the condition of water passing through the heat exchanger 2 is detected by the water flow rate sensor 7 in the initial stage of the installation of the apparatus, the above-mentioned temperature keeping combustion starting condition is satisfied until the set condition for starting the warming combustion is satisfied. It is configured to control the warming combustion control. That is, if the warming combustion control is executed immediately after the hot water supply device is newly installed and the operation switch 15 is turned on, the hot water keeping water control is started before the water flow to the heat exchanger 2 is started. When the combustion of the burner 3 is started based on the detection information of the temperature thermistor 20, the burner 3 is heated in a state where hot water does not exist inside the heat exchanger 2 and becomes a so-called idle-fired state. In such a case, the flow of water to the heat exchanger 2 is detected, and the normal combustion control is executed. Thereafter, after the passage of water is stopped, the warming combustion control is executed so as to check the warming combustion control.

The combustion control of the burner 3 in the above-mentioned warm combustion is executed by the configuration shown in the control circuit block diagram of FIG. In other words, when the water flow rate sensor 7 does not detect the flow of water through the hot water path, and therefore, in a state where the water flow rate signal is not output from the water flow rate detection circuit C1, the detection value of the warming water temperature thermistor 20 becomes equal to or less than the set lower limit value. Then, when the above-described setting condition for the start of the warming combustion is satisfied, the microcomputer shown in FIG. The same pseudo signal as the pulse signal exceeding the corresponding pulse number) is output, and the pseudo signal is input to the transistor drive circuit C2 to turn on the first transistor T1. And
With the same operation as the above-described normal combustion, the burner 3 is burned to start the warming combustion. When the detected value of the hot water temperature thermistor 20 exceeds the set upper limit, the combustion of the burner 3 is stopped. Have been.

In the configuration shown in FIG. 5 (b), when the set condition for the start of warming combustion is satisfied, a pseudo signal corresponding to the water flow signal is directly input to the transistor driving circuit C2 and the first transistor T1 Is turned on, but the output line of the water flow signal from the water flow signal generation means S1 and the output line of the pseudo signal from the microcomputer are connected to an OR circuit, and the output from the OR circuit is connected. The line may be connected to the transistor driving circuit C2 so that the water passing signal or the pseudo signal is input to the transistor driving circuit C2. Further, the output line from the transistor drive circuit C2 for the first transistor T1 and the output line from the microcomputer may be connected to an OR circuit, and the output line from the OR circuit may be connected to the first transistor T1. it can. In this manner, the pseudo signal may not be directly input to the transistor drive circuit C2, but a pseudo command corresponding to the combustion permission command may be issued to the combustion state switching means S2.

Next, the control operation of the control unit H will be described with reference to the control flowchart shown in FIG. When the power is turned on to the hot water supply device and the operation switch 15 is not turned ON, the heat retention flag is set to the "OFF" state and the operation is on standby (steps 1 and 2). Then, after the operation switch 15 is turned ON, as the hot water tap is opened, the detection value of the water flow sensor 7 exceeds the set water flow, and the flow (water flow) to the heat exchanger 2 is detected. Then, the normal combustion control is executed. That is, the burner 3 is ignited and burned, and the combustion amount of the burner 3 and the ventilation amount of the fan 4 are adjusted so that the tapping temperature detected by the tapping temperature thermistor 9 becomes the target temperature set by the temperature setting switch 16. The control is performed (steps 3 to 5), and the process is executed until the hot water tap is closed and the passage of water is no longer detected or the operation switch 15 is turned off (steps 6 and 7). Even if the operation switch 15 is turned on, if water is not detected, it is determined whether or not the heat retention flag is set to the “ON” state. Since the heat retention flag is set to the "OFF" state,
Returning to step 1, the apparatus enters a standby state until a water flow is detected (step 12).

When the hot water tap is closed and the detected value of the water flow rate sensor 7 falls below the set water amount during normal combustion control, the combustion of the burner 3 is stopped and the heat retention flag is set to "ON". "State (steps 6, 8, 9) and waits until water flow is detected.
If the operation switch 15 is turned off while the normal combustion control is being executed, the combustion of the burner 3 is stopped, and the heat retention flag is set to the "OFF" state (steps 7, 10, 11). , The operation is in a standby state until the operation switch 15 is turned on. Therefore, the operation switch 15
Is turned on and the normal combustion control based on the detection of water flow is performed, and when the water flow is not detected and the combustion of the burner 3 is stopped, the heat retention flag is set to the “ON” state. Then, even if the operation switch 15 is not turned on, or even if the operation switch 15 is turned on, if the passage of water has never been detected, the heat retention flag is set to “OFF”.

When the operation switch 15 is turned ON and the passage of water is not detected, the heat retention flag is set to "O".
N ”state, the hot water temperature thermistor 2 based on the detection information of the hot water temperature thermistor 20.
When it is determined that the detected value Tx of 0 has become equal to or less than the set value lower than the set temperature α by the set amount α, the combustion operation for keeping the heat of the burner 3 started, and the temperature of the hot water inside the heat exchanger 2 is reduced. A warming operation is performed so that the temperature does not fall significantly below the hot water target temperature Ts (steps 12, 13, and 14), and the detection value Tx of the hot water temperature thermistor 20 becomes equal to the hot water target temperature Ts.
When it is determined that the set value β is equal to or higher than the set value β higher than s, the warm combustion of the burner 3 is stopped (steps 15 to 18). When the hot-water tap is opened and water is detected during the execution of the warm combustion, the process proceeds to step 5 to execute the normal combustion control (step 15), and the warm combustion is performed. When the operation switch 15 is turned OFF while the operation is executed, the heat retention flag is set to the "OFF" state, and the heat retention combustion of the burner 3 is stopped (steps 16, 19, 20).

The temperature for determination as the condition for starting the warming combustion is a temperature lower than the target temperature for hot water by a set amount α.
Since the determination temperature as the stop condition is a temperature that is higher than the target temperature for tapping by the set amount β, when the target temperature Ts is changed and set based on the operation of the temperature setting switch 16, the determination temperature is accordingly changed. The temperature will also change,
The hot and cold water in the hot water passage inside the apparatus is heated and kept at a temperature close to the target temperature Ts. Note that the set amounts α, β
Will be set appropriately according to the characteristics of the water heater,
These set amounts α and β may be different values or may be set to the same value.

As described above, in the hot water supply standby state in which the hot water supply is stopped, the hot and cold water in the pipeline inside the heat exchanger 2 is
The temperature is always kept at the target temperature Ts or a temperature close to the target temperature Ts.
Alternatively, hot or cold water at a temperature close to that is supplied, which makes it easy to use.

[Another Embodiment] <1> In the above embodiment, as one of the setting conditions for stopping the warming combustion, the detection value of the warming hot water thermistor 20 is set to the target temperature changed and set by the temperature setting switch 16. Although an example in which the temperature exceeds a temperature higher than the set amount has been described, the following configuration may be used instead of such a configuration. In other words, the condition may be that the detected value of the hot water temperature thermistor 20 exceeds a predetermined temperature, and the detected value of the hot water temperature thermistor 20 when the normal combustion control is executed. May be stored, and if the detected value of the hot water temperature thermistor 20 exceeds a temperature higher than the stored value by a set amount, the warming combustion may be stopped. Further, the configuration may be such that when the set time has elapsed since the start of the warm combustion, the warm combustion is automatically stopped. In such a configuration, the determination condition based on the temperature in step 17 in FIG. Instead, it is determined whether or not a set time has elapsed from the start of combustion. Further, a configuration in which the determination based on the passage of time and the determination based on the temperature in the above embodiment may be used in combination.

<2> In the above-described embodiment, one of the set conditions for starting the warming combustion is that the hot water temperature thermistor 2
Although the case where the detection value of 0 is lower than the temperature lower than the target temperature by the set amount has been described as an example, instead of such a configuration,
The following configuration may be adopted. In other words, the condition may be that the detected value of the hot water temperature thermistor 20 is lower than a predetermined temperature set in advance, and the detected value of the hot water temperature thermistor 20 when the normal combustion control is performed. May be stored, and when the detected value of the hot water temperature thermistor 20 falls below a temperature lower than the stored value by a set amount, the warming combustion may be started. Further, it may be configured such that when the set time for keeping heat elapses from the time when the combustion of the burner 3 is stopped in the normal combustion control, the kept warm combustion is started. The set time for the heat retention may be a fixed time set in advance, or
Depending on the outside air temperature or the incoming water temperature, the temperature may be changed to a short time if the temperature is low, and may be changed to a long time if the temperature is high.

<3> In the above-described embodiment, the heat retention control restraint means is configured to only restrain the heat retention combustion control until water flow to the heat exchanger 2 is detected at the initial stage of installation. In addition to the operation, the following check operation may be performed. In other words, if the passage of water is not detected even after the set standby time (for example, about several hours) has elapsed since the stop of the normal combustion control, the execution of the warmed combustion control may be suppressed. Good. For example,
In the case where the hot water supply user goes to bed or the like, the hot water supply is not performed until the next morning, so it is not necessary to execute the warming combustion control. However, if the operation of turning off the operation switch 15 is forgotten, Since the insulated combustion control is executed and energy loss occurs, in such a case, the execution of the insulated combustion control is suppressed. When a specific operation of the check operation is added, as shown in FIG. 8, step 3 of the control operation of FIG.
During the transition from step to step 12, it is determined whether or not the set time has elapsed since the previous combustion stop of the normal combustion operation of the burner 3, and if it has elapsed, the heat retention flag is set to the "OFF" state. Return to Step 1 (Step 2
1, 22). Note that other control operations are the same as those in the above-described embodiment, and a description thereof will be omitted.

If the target temperature for tapping is within a set temperature range in which hot water is expected to be used only for a short time,
You may comprise so that execution of the said heat retention combustion control may be checked. For example, if the target temperature is in a temperature range of about 35 ° C. to 50 ° C., it is a temperature that is safe to touch the body for a long time, such as washing dishes or filling a bathtub, and a relatively long time. It is conceivable that hot water is supplied over a long period. However, if the temperature is higher than 60 ° C., there is a danger of burns when touching the body, so it is unlikely that hot water will be supplied for a long time. Since it is predicted that hot water will be used, in such a case, there is no need to perform warming combustion control thereafter, so the operation is restrained. The specific operation of this check operation will be described. As shown in FIG. 9, step 9 of the control operation of FIG.
In the above, it is determined whether or not the target temperature Ts is in a set temperature range in which it is predicted that hot water will be used only for a short time, as a condition for setting the heat retention flag to the “ON” state;
If it is not in such a temperature range, turn on the heat retention flag.
State, and if it is in that temperature range, the heat retention flag is maintained in the "OFF" state (step 2).
3, 24, 25). For other control operations,
The description is omitted because it is the same as the above embodiment.

<4> In the above embodiment, the control section H is provided in the control program form as the heat retention control restraining means. Instead of such a configuration, for example, the control section H is provided in the remote control operation section or the like. For example, a mode switch for instructing the control mode to be switched between a state where the warm combustion control is performed and a state where the warm combustion control is not performed may be provided.

<5> In the above embodiment, the hot water temperature thermistor for detecting the temperature of hot water in the heat exchanger 2 is used as the hot water temperature detecting means for setting the setting conditions for starting and stopping the warming combustion. Although the case where 20 is provided is illustrated, instead of such a configuration, a configuration may be adopted in which the heat retention combustion control is executed based on the detection information of the tapping temperature thermistor 9.

<6> In the above embodiment, the water inlet 5 and the hot water outlet 6 are connected to the heat exchanger 2, and the entire amount of water supplied from the water inlet 5 is heated by the heat exchanger 2. The hot water is supplied from the hot water supply path 6 after the hot water supply, but instead of such a configuration, the following configuration may be adopted. For example, FIG.
As shown in FIG.
An outlet hot water thermistor 32 for detecting the hot water temperature at the outlet of the heat exchanger 2, and a mixed hot water thermistor for detecting the mixed hot water temperature. 33, the bypass valve 31 is opened to supply a relatively large amount of hot water at a relatively low temperature, and the bypass valve 31 is closed to supply hot water at a high temperature. When the valve 31 is opened, in the normal combustion control, the outlet hot water temperature thermistor 3
The feed amount of the burner 3 is controlled by feedforward control based on the detected information of the burner 3 and the target temperature, and the burned amount of the burner 3 is feedback-controlled based on the detected information of the mixed bath temperature thermistor 33 so that the mixed bath temperature becomes the target temperature. Configuration.
In the configuration in which such a bypass is provided, hot water whose temperature has been increased by warm combustion is discharged while being mixed with water supplied from the bypass 30 by the start of normal combustion. In this case, if the temperature of the supply water is originally high, the overshoot of the discharged mixed hot water may be severe. However, according to the configuration of the device of the present invention, when the temperature of the supply water is high, the heat retention combustion is performed. Therefore, overshooting of the mixed hot water can be prevented.

As shown in FIG. 11, a mixing valve 34 whose distribution ratio can be changed and adjusted is provided at the junction of the bypass path and the tapping path 6 on the heat exchanger 2 side. The combustion amount of the burner 3 is adjusted so that the detected value of 32 is maintained at a set temperature (for example, 80 ° C.), and the mixing ratio of the mixing valve 34 is adjusted and controlled such that the temperature of the mixed hot water reaches the target temperature. There may be.

<7> In the above embodiment, the hot water detecting means makes the incoming water temperature thermistor 8 self-heat,
Although the configuration in which the presence or absence of hot water is determined based on the cooling efficiency at that time has been described, for example, an open / close valve that can open and close the hot water path is provided, and the presence or absence of hot water is determined based on the open / close resistance of the open / close valve. That is, any device that can determine the presence or absence of hot water in the hot water path may be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a water heater.

FIG. 2 is a partially cutaway front view of the heat exchanger.

FIG. 3 is a plan view of a heat exchanger.

FIG. 4 is a side view of the heat exchanger.

FIG. 5 is a circuit block diagram illustrating an ignition operation of combustion control.

FIG. 6 is a circuit diagram illustrating an ignition operation of combustion control.

FIG. 7 is a flowchart of a control operation;

FIG. 8 is a flowchart of a control operation according to another embodiment.

FIG. 9 is a flowchart of a control operation according to another embodiment.

FIG. 10 is a schematic configuration diagram of a hot water supply unit according to another embodiment.

FIG. 11 is a schematic configuration diagram of a hot water supply unit according to another embodiment.

[Explanation of symbols]

 2 Heat Exchanger 3 Burner 5 Water Inlet 6 Hot Water Outlet 20 Hot Water Temperature Detecting Means C2 Switching Operation Circuit H Burner Control Means S1 Water Flow Signal Generating Means S2 Combustion State Switching Means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-204064 (JP, A) JP-A-3-2133952 (JP, A) JP-A-3-57345 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) F24H 1/10 301 F24H 1/10 302

Claims (6)

(57) [Claims] 1. A water heating heat exchanger for heating water supplied through an inlet channel by burning a burner and discharging hot water from a hot water channel, and detecting a water flow to the heat exchanger to generate a water flow signal. Means for generating a water flow signal to be generated, combustion state switching means for switching between a combustion state in which fuel is supplied to the burner and burning, and a non-combustion state in which fuel supply is stopped to stop combustion, and the water flow signal generation means When a water flow signal is generated from the means, a combustion command to make the combustion state switching means in a combustion state is instructed, and when the water flow signal from the water flow signal generation means is stopped, the combustion state switching means is activated. Burner control means for executing a normal combustion control for instructing a combustion stop command for setting a non-combustion state; and combustion permission for setting the combustion state switching means to a combustion state when a water flow signal is generated from the water flow signal generation means. Command. A switching operation circuit for instructing a combustion non-permission command to set the combustion state switching means to a non-combustion state when the water signal from the water signal generation means is stopped; and A hot water supply device configured to be switched to the combustion state only when both the command and the combustion permission command are issued, wherein the burner control means stops water flow to the heat exchanger. In this state, if the set condition for the start of warming combustion is satisfied, the combustion command is commanded, and the switching operation circuit issues a combustion permission command, or a pseudo state for setting the state corresponding thereto. A hot water supply device configured to execute a warming combustion control for issuing a command. 2. The burner control means is configured to output a pseudo signal corresponding to the water flow signal to the switching operation circuit as the pseudo command when the set condition for starting the warming combustion is satisfied. The hot water supply device according to claim 1, wherein 3. The burner control means is configured to stop the command of the pseudo command and stop the command of the combustion command when a set condition for stopping the warming combustion is satisfied. The hot water supply device according to 1 or 2. 4. A hot water temperature detecting means for detecting a temperature of hot or cold water in the hot water path or the heat exchanger, wherein the burner control means determines that a temperature detected by the hot water temperature detecting means falls below a set lower limit. The hot water supply device according to any one of claims 1 to 3, wherein the hot water supply device is configured to determine that the set condition for starting the warmed combustion is satisfied. 5. The system according to claim 5, wherein said burner control means determines that the set condition for stopping the warming combustion is satisfied when a value detected by said hot water temperature detecting means is equal to or more than a set upper limit value. Item 6. A hot water supply device according to item 4. 6. The burner control means is configured to determine that, when a set time has elapsed from the start of combustion of the burner in the warming combustion control, the set condition for stopping the warming combustion has been satisfied. The hot water supply device according to claim 3.