JPH10103774A - Hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to supply hot water which is near to a desired temperature without further complicating the constitution of a hot water device as soon as possible when starting the supply of hot water and operate economically the hot water supply device. SOLUTION: In a state where the supply of water to a heat exchanger 2 is suspended, there is provided a heat insulation combustion control means 101 which starts the combustion of a burner 3 when the temperature of hot water in the heat exchanger 2 drops below a first setting temperature and stops the combustion of the burner 3 when the temperature of hot water in the heat exchanger 2 exceeds a second setting temperature; there is also provided a heat insulation combustion control stop means 102 which stops the heat insulation combustion control when the differential temperature between hot water temperature in a hot water supply line 6 and water supply temperature in a water supply line 5 drops below a specified differential value.

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 a hot water supply line by heating water supplied through a water supply passage by burning a burner, and starting water flow to the heat exchanger. And a control means for executing normal combustion control for starting the combustion of the burner as the water is supplied and stopping the combustion of the burner as the flow of water is stopped.

[0002]

2. Description of the Related Art Conventionally, in the above-mentioned hot water supply apparatus, the normal combustion control is always executed, and after the tapping from the tapping path is stopped, until the tapping from the tapping path is started again. In this configuration, the flow of water to the heat exchanger was stopped, and the burner was kept in a combustion stopped state.

[0003]

In the above-mentioned conventional construction, if the time from when the tapping from the tapping channel is stopped to when tapping is started again becomes long, the temperature of the heat exchanger heated by the burner decreases. Then, the hot water in the heat exchanger will drop to a temperature close to the temperature of the supply water, and when the hot water is re-started, hot water of such a low temperature is discharged and the temperature is falling. There is a disadvantage that it takes time until the heat exchanger is heated by the burner and the hot water temperature rises to a desired temperature. Therefore, as a method for solving such disadvantages, a circulation path is formed by connecting a hot water path and a water intake path, and a circulation pump is provided in the circulation path, and the hot water is stopped to burn the burner. When stopped, the circulation pump is intermittently operated to circulate hot water through the circulation path and through the heat exchanger, thereby burning the burner intermittently and heating the heat exchanger. As a configuration for maintaining the hot water temperature in the circulation path at a set hot water temperature, there has been a configuration in which hot water having a temperature close to a desired temperature can be supplied with little time delay at the start of re-watering (for example,
JP-A-61-116237). However, in the above configuration, a special piping and a circulating pump for forming a circulation path are required, the number of parts is increased, the configuration becomes more complicated, and there is a disadvantage of increasing the cost. There was room for improvement.

The present invention has been made in view of this point, and an object of the present invention is to supply hot water having a temperature close to a desired temperature as quickly as possible at the start of tapping without complicating the configuration. Another object of the present invention is to provide a hot water supply apparatus which can be operated economically.

[0005]

A feature of the present invention for achieving the above object is to provide a water heater for heating water supplied through an inlet passage by burning a burner and discharging the water from the outlet passage. Is provided, and the combustion of the burner is started as the flow of water to the heat exchanger is started, and the combustion of the burner is stopped as the flow of the water is stopped. A normal combustion control means for executing normal combustion control is provided, and in a state in which water flow to the heat exchanger is stopped, when the temperature of hot water in the heat exchanger becomes equal to or lower than a first set temperature, the burner is activated. When starting the combustion, when the hot water temperature in the heat exchanger becomes equal to or higher than the second set temperature, a warming combustion control means for performing warming combustion control for stopping the combustion of the burner is provided, and the hot water temperature in the hot water path is provided. The difference with the supply water temperature in the inlet channel is less than the specified temperature difference In this case, a warming combustion control stopping means for stopping the warming combustion control is provided (corresponding to claim 1), and the water supplied through the water inlet passage is heated by burning the burner, and the hot water is discharged from the hot water passage. A heat exchanger for heating water is provided, and combustion of the burner is started as water flow to the heat exchanger is started, and combustion of the burner is stopped as water flow is stopped. A water heater provided with normal combustion control means for executing normal combustion control to stop, in a state in which water flow to the heat exchanger is stopped, after the first set time has elapsed after the combustion of the burner is stopped, Providing insulated combustion control means for performing insulated combustion control to perform the combustion of the burner for a second set time, when the difference between the hot water temperature in the tap water channel and the water supply temperature in the water inlet channel is equal to or less than a predetermined temperature difference, Stop warm combustion control to stop warm combustion control A step may be provided (corresponding to claim 2), and a bypass path is provided for bypass-connecting the water inlet path and the hot water path without passing through the heat exchanger. A mixed hot water temperature detection for detecting a mixed hot water temperature in which water from an inlet channel and hot water upstream of the confluent portion in the hot water path are mixed on the downstream side of the hot water path with respect to the hot water path. Means for stopping the warming combustion control when the difference between the mixed hot water temperature detecting means and the water temperature from the water inlet becomes equal to or less than a predetermined temperature difference. Good (corresponding to claim 3). When the predetermined temperature difference is set in the above-described configuration, it is preferable that a setting change unit that changes the setting of the predetermined temperature difference be provided (corresponding to claim 4). It is preferable that a setting change means for changing the setting of the predetermined time is provided (corresponding to claim 5), and the normal combustion control is performed after the thermal combustion control is stopped by the thermal combustion control stopping means. It is preferable that a warm combustion control start means for restarting the warm combustion control when the normal combustion control is stopped is provided (corresponding to claim 6).

[Effects] That is, when the tapping of hot water is stopped and the flow of water to the heat exchanger is stopped, the set conditions for starting the warming combustion, for example, the temperature of the hot water inside the heat exchanger decreases. (Corresponding to claim 1) In the case where a time has elapsed such that the temperature of the heat exchanger decreases after the tapping is stopped (claim 2).
If the conditions that can be considered as lowering the temperature of the hot and cold water inside the heat exchanger are met, the burner starts combustion regardless of the presence or absence of water flow to the heat exchanger. Heat the hot water inside the exchanger. Then, the set conditions for stopping the warming combustion, for example, when the hot water temperature inside the heat exchanger rises to the set temperature (corresponding to claim 1), or when the set time has elapsed since the start of burner combustion ( When the condition that the temperature of the hot water in the heat exchanger can be considered to have risen to a desired temperature or a temperature close to the desired temperature is satisfied, the combustion of the burner is stopped.

Therefore, as compared with the conventional configuration in which the combustion of the burner is only started with the passage of water to the heat exchanger, a special member for passing water to the heat exchanger in a state in which tapping is stopped. Is unnecessary, and without complicating the configuration,
It is possible to execute a heat retention operation to maintain the temperature of the hot water inside the heat exchanger at the desired temperature or a temperature close to the temperature as much as possible. It can be used.

[0008] By the way, although the hot water can be supplied at a desired temperature quickly with the passage of water to the heat exchanger, according to the above-described configuration, the hot water in the hot water discharge passage downstream of the heat exchanger is provided. The temperature of the hot water cannot be controlled, and it is conceivable that the water in the hot water path becomes low temperature, so-called “dead water”. In such a case, for example, in a case where the pipe of the tapping channel is extremely long, after the hot water supply device is stopped, the water in the tapping channel until the hot water in the heat exchanger reaches a hot water supply port such as a faucet. When the water becomes dead, a large amount of water will be discharged from the hot water supply port before the hot water in the heat exchanger is kept warm when the hot water supply device is operated again. Even if the temperature of the hot and cold water in the heat exchanger is about the desired temperature, the ratio decreases, and the rate of benefit of keeping the hot and cold water in the heat exchanger at the desired temperature decreases. In addition, there is no large difference in the degree of satisfaction of users of hot and cold water. In other words, in the above case, the warm combustion control will not function effectively,
If developed further, regardless of the length of the pipe of the hot water supply channel, if the water in the hot water supply channel is dead water, the heat retention combustion control will work wastefully, and the energy for the heat retention combustion control will be It can be said that there is a risk of being wasted.

Therefore, the difference between the temperature of the water supplied to the heat exchanger and the temperature of the water in the tapping water becomes less than a predetermined temperature difference.
2), when the hot and cold water in the hot water supply path is considered dead, if the warming combustion control stopping means stops the warming combustion control, the amount of energy required for the warming combustion control can be saved. That made it possible to operate the water heater economically.

In particular, in the case where a bypass path is provided to connect the water inlet path and the hot water path by bypass without passing through a heat exchanger (corresponding to claim 3), hot water will be used. There is a situation in which the desired hot water temperature differs between the person who uses the hot water and the person who uses the hot water earlier than the person, and the desired hot water temperature of the person who uses the hot water first uses the hot water later. In some cases, the temperature of the hot water may be lower than the desired hot water temperature of the person who intends to do so, and it becomes necessary to perform the warming combustion control more accurately. At this time,
Since the temperature of the mixed hot water used by the person who used the hot water first dropped in the hot water path downstream of the junction of the hot water path and the bypass path, the hot water died, A mixed hot water temperature detecting means for detecting the mixed hot water temperature is provided, and the difference between the mixed hot water temperature and the temperature of the water from the inlet channel is compared with a predetermined temperature difference. If it is configured to be able to determine whether or not to continue, regardless of the level of the mixed hot water used by the previous hot and cold water users, it is possible to accurately perform the heat retention combustion control that meets the hot water users' expectations. Become.

In the above-described configuration, the predetermined temperature difference when the predetermined temperature difference is set, and the predetermined time when the predetermined time is set, are determined by the difference in the use form of the hot water path, the season, and the regional difference. Depending on the state difference (difference in use environment), the predetermined temperature difference and the predetermined time greatly differ. In a single setting, the insulated combustion is not performed even though the insulated combustion control is expected. In spite of the fact that the heat-retention combustion control is not expected, the heat-retention combustion control may be wastefully performed and energy may be wasted, and the heat-retention combustion control is accurately performed in response to such a situation. Things are expected. In such a case, if a setting change unit for changing the setting of the predetermined temperature difference (corresponding to claim 4) is provided, the setting of the predetermined temperature difference can be changed, and the setting can be changed regardless of the difference in the use environment. In addition, it is easy to realize the optimum state of the warming combustion control desired by the user. Further, if the warming combustion control is stopped by the warming combustion control stopping means in the above-described configuration, even in a situation where a desired hot water temperature is desired to be quickly obtained, the previous user can use the hot water after the hot water is used. If the hot water is used after the stop means has been activated, the warm combustion control will not be activated until the next user uses the hot water, which may hinder comfortable use of the hot water. Therefore, if the warm combustion control is stopped, the normal combustion control is performed, and if the warm combustion control is stopped, the warm combustion control starting means for restarting the warm combustion control is provided (claim 8). Response), when using the hot water supply device under the condition that the user wants to control the heat retention and combustion, especially when using hot and cold water, it is not necessary to confirm whether the condition of the heat retention and combustion can be controlled. Combustion control can be performed accurately, and the comfortable use of hot water can be improved. When the user uses the hot water supply apparatus under the condition that the user does not want to perform the heat retention combustion control, it is sufficient to set the heat retention combustion control means of the water heater to be incapable of executing the heat retention combustion control. Therefore, there is no problem such as inconvenience that the insulated combustion control must be performed.

[0012] As a result, it is possible to accurately perform the warming combustion control operation, and to easily realize comfortable use for the user of the water heater while realizing energy saving.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hot water supply apparatus according to the present invention will be described. As shown in FIG. 1, the hot water supply apparatus includes a hot water supply unit K for heating supplied water and supplying hot water to a hot water tap (not shown), a control unit H as control means for controlling the operation of the hot water supply unit K, A remote control operation unit R for instructing the H to input operation information is provided.

The hot water supply unit K includes a heat exchanger 2 for heating water, a gas-fired burner 3 for heating the heat exchanger 2, and a combustion air flowing through the burner 3 in the combustion chamber 1. The heat exchanger 2 is provided with a fan 4 and the like whose flow amount can be changed and adjusted, and the heat exchanger 2 is supplied with water from a domestic water supply or the like, for example, and receives hot water from a hot water tap. The hot water path 6 is respectively connected, and the water inlet path 5 is provided with a water flow rate sensor 7 as a water flow state detecting means for detecting a water flow rate to the heat exchanger 2 and an input water temperature thermistor 8 for detecting an input water temperature. The tapping path 6 is provided with a tapping temperature thermistor 9 for detecting tapping temperature.

The fuel supply passage 10 for the burner 3 is provided with an electromagnetically operated on-off valve 11 for intermitting fuel supply, and an electromagnetically operated on / off valve as a combustion amount adjusting means capable of changing and adjusting a fuel supply amount (a combustion amount of the burner 3). Is provided with a gas amount control valve 12 of
An igniter 13 for executing an ignition operation for the burner 3 and a frame rod 14 for detecting whether or not the burner 3 is ignited are provided near the burner 3 respectively.

The remote controller R is provided with 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 capable of changing and setting a target temperature for tapping, and a warming combustion control. Mode switch 17 for switching between enabling and disabling, a display unit 18 for displaying tap water temperature, target temperature, and the like; operating state; burner 3 in burning state; The status display lamps 19 and the like for indicating that the operation is being performed are provided.

The control unit H is provided with a microcomputer, and performs normal combustion control means 100 for performing normal combustion control during hot water supply, warm combustion control means 101 for performing warm combustion control during hot water supply standby, Warming combustion control stopping means 102 for stopping the execution of the combustion control,
Insulation control start means 103 for starting the insulated combustion control
Are provided in the form of a control program.

The normal combustion control means 100 includes a hot water supply section K
In the state where is set to the operating state, the combustion of the burner 3 is started with the passage of water to the heat exchanger 2 and the passage of water to the heat exchanger 2 is stopped. In addition to controlling the combustion of the burner 3 to stop, when the flow of water to the heat exchanger 2 is detected, the normal combustion control for adjusting the amount of combustion of the burner 3 so that the hot water temperature reaches the target temperature is executed. It is configured to be. Specifically, in the normal combustion control, the control unit H performs the following control operation. That is, after the operation state is set in accordance with the ON operation of the operation switch 15, the flow rate detected by the flow rate sensor 7 in response to the opening operation of the hot water tap exceeds the set flow rate and the flow rate to the heat exchanger 2 is increased. When the water flow state is detected, the ventilation operation by the fan 4 is started, the intermittent valve 11 is opened, and the gas amount control valve 12 is opened and adjusted to the ignition gas amount, and the igniter 13 is opened. As a result, a spark is generated to start the ignition operation for the burner 3, and when the ignition state is detected by the frame rod 14, the ignition operation by the igniter 13 ends. Then, based on the detection information of each of the incoming water temperature thermistor 8, the outgoing water temperature thermistor 9, and the flow rate sensor 7, and the information on the target temperature set by the temperature setting switch 16, the tap water temperature is set to the target temperature. The required combustion amount of the burner 3 is calculated by calculation, and the gas amount control valve 12 is adjusted and controlled so as to have a gas amount corresponding to the calculated combustion amount. The ventilation amount of the fan 4 is adjusted and controlled so as to achieve an appropriate combustion state. In this way, hot water at the target temperature is supplied from the hot water supply path 6.

The warming combustion control means 101 comprises:
In a 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, when the set condition for starting the warming combustion is satisfied, the combustion of the burner 3 is started to stop the warming combustion. When the set condition is satisfied, the warming combustion control for stopping the combustion of the burner 3 is executed.

More specifically, a hot water temperature thermistor 20 is provided as a 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 less than or equal to the first set value in a state where the burner 3 is stopped, it is determined that the set condition for starting the warmed combustion is satisfied, and the combustion of the burner 3 is started. When the detected value of the hot water temperature thermistor 20 becomes equal to or more than the second set value, it is determined that the set condition for stopping the warming combustion is satisfied, and the combustion of the burner 3 is stopped. . In this way, in the hot water supply standby state, the temperature of the hot water in the hot water path inside the hot water supply device is prevented from lowering and is maintained between the first set value and the second set value. The hot water of the target temperature can be discharged as quickly as possible.

The hot water temperature thermistor 20
Is provided in a portion of the hot water passage in the heat exchanger 2 which is easily heated by the combustion of the burner 3 and in which the temperature of the hot water is liable to drop during standby for hot water supply. That is, FIG.
As shown in FIG. 4, the heat exchanger 2 is disposed in a state where a plurality of fin tube type heat exchange pipe sections 2 a are vertically stacked and extends over the left and right side walls 1 A and 1 B constituting the combustion chamber 1. And a plurality of U-shaped tubes 2b on the outer side of the left and right side walls 1A and 1B so that they form a series of pipes connected in a meandering manner. Further, the hot water temperature thermistor 20 is provided in the U-shaped tube 2b located near the heat exchange pipe portion 2a located on the lower side.

The incoming water temperature thermistor 8 is provided outside the combustion chamber 1 and in the vicinity of the water flow rate sensor 7 so as to accurately detect the incoming water temperature of the supply water in the incoming water channel 5. Is provided at a position outside the combustion chamber 1 that is not easily affected by the heat exchanger 2 so as to accurately detect the temperature of the hot and cold water inside the hot water path 6 and determine whether or not the water has died. It is. Thus, the difference between the incoming and outgoing water temperatures between the incoming and outgoing water temperatures can be accurately obtained.

Therefore, the above-mentioned warm combustion control is performed by the warm combustion control means 101, and the control section H is provided with a warm combustion control stop means 102 and a warm combustion control start means 103, and the warm combustion control is performed. Is not to be performed, the warm combustion control stop means 102 stops the warm combustion control. When the warm combustion control is required again after the stop of the warm combustion control, the warm combustion control is started by the warm combustion control start means 103. It is configured to start. That is, when the temperature difference between the incoming and outgoing water is small and the result of the insulated combustion control is not exerted, specifically, when the temperature difference between the input and output water is smaller than a predetermined temperature difference, the insulated water combustion is controlled. Even if it is set to perform the control (thermal combustion control mode), the thermal combustion control is stopped so as not to be performed, and the thermal combustion control is stopped when the normal combustion is performed next time. When the control setting is ON,
At the end of the normal combustion (at the time of stopping the passage of water), the warming combustion control starting means 103 restarts the warming combustion control again.

Next, the control operation of the controller H will be described with reference to the control flowchart shown in FIG. When the power is supplied 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 because the heat retention combustion control is not required (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 the combustion amount of the burner 3 and 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.
Is controlled (steps 4 to 6). Such a control is performed when the water tap is closed and the water flow is no longer detected,
Alternatively, the process is executed until the operation switch 15 is turned off (steps 7 and 8). The operation switch 15 is ON
Even if the device is in operation, if the water flow is not detected, it is determined whether or not the heat retention mode is set to the “ON” state. Even if it is set to the “OFF” state, the process returns to step 1 and is in a standby state until the water flow is detected.

Here, between step 1 and step 4, whether or not the user expects to perform warming combustion control at normal times is identified by the state of the warming mode switch and the warming flag is set. If the heat retention mode switch 17 is OFF, the heat retention flag is set to OFF assuming that the heat retention combustion control is not to be performed, and the process returns to step 1 in step 14 and the heat retention mode switch 17 is ON. Indicates whether or not the warming combustion control is necessary, by setting the warming flag O which has already been set.
Judge from N, OFF. This functions as a warming combustion control stopping means. When the warming combustion control is not required, the warming flag is turned off and the warming mode switch 17 is turned on.
Regardless, the process returns to step 1 in step 15. If the thermal insulation control stop means does not work, the process continues to step 16 and subsequent steps for performing thermal insulation combustion control.

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 mode switch 17 is turned off. The heat retention flag is reset based on the state. That is, if the heat retention mode switch 17 is in the ON state, the setting change for turning on the heat retention flag is performed regardless of the current state of the heat retention flag (when the heat retention mode is OFF, the heat retention flag is kept OFF).
(Steps 10 and 11). And it will be in a standby state until a water flow is detected. Therefore, Step 3 and Step 1
Numerals 0 and 11 function as a warming combustion control start means. When the normal combustion control is finished, the warming flag is set by the state of the warming mode switch 17. That is, when the normal combustion control is completed, the heat retention mode switch 1
If 7 is ON, the heat retention flag is set to ON and the process returns to step 1. If the heat retention mode switch is OFF, the heat retention flag is set to OFF and the process returns to step 1. When the operation switch 15 is turned off during the normal combustion control, the burner 3
Is stopped, and the heat retention flag is set to the "OFF" state (steps 8, 12, and 13), and a standby state is set until the operation switch 15 is turned on. In this case, the heat retention flag is set to OFF regardless of the state of the heat retention mode switch 17.

When the operation switch 15 is turned ON and the water flow is not detected, the warming mode is set to O.
If N and the heat retention flag is set to the "ON" state, it is determined in step 16 whether or not the heat retention combustion is necessary (step 16). That is, when the temperature difference between the water temperature of the water inlet channel 5 and the temperature of the hot water of the hot water channel 6 (input / output water temperature difference) is larger than a predetermined temperature difference set in advance, it is determined that the warm combustion control is required. Judge and proceed to step 18,
If the incoming and outgoing water temperature difference is equal to or less than the predetermined temperature difference, it is determined that the temperature of the hot and cold water in the hot water passage is too low to be dead water, and that it is in a state where the heat retention combustion control is unnecessary, Turn off the heat retention flag (Step 17) and wait for the normal combustion mode based on water flow Step 1
Go back.

If it is determined in the above steps that the difference between the incoming and outgoing water temperature is equal to or more than the predetermined temperature difference and that it is necessary to perform the heat-retention combustion control, the burner 3 is set to the heating state to perform the heat-retention combustion control.
It is determined whether or not N operations are required (step 1)
8). That is, based on the detection information of the hot water temperature by the hot water temperature thermistor 20, if the hot water temperature is equal to or higher than a lower limit (first set temperature) of a set value lower than the target temperature for hot water supply, the temperature is maintained. Since the combustion control is necessary, it is not necessary to turn on the burner 3 yet, and the process returns to step 1. On the other hand, the hot water temperature thermistor 20
When the temperature of the hot water is lower than the first set temperature, the burner 3 is turned on based on the information of the temperature of the hot water.
Then, the combustion operation of the burner 3 is started (step 19), and the heat retention operation is performed so that the temperature of the hot water inside the heat exchanger 2 does not drop significantly below the target temperature for tapping. Proceed to steps 20 to 23 to be executed.

When the water flow is detected during the execution of the heat retaining operation, it is determined that the normal combustion needs to be performed (step 20), and the process proceeds to step 6, and the operation switch is turned off during the execution of the heat retaining operation. If detected (Step 2
1), it is determined that the heat retention combustion control itself is unnecessary, and the heat retention flag is turned off (step 24), and the burner 3 is turned off (step 25), and the process returns to step 1 to wait for the operation of the water heater. State. If the water flow is not detected and the operation switch 15 is not turned off, it is determined whether or not the temperature of the hot water needs to be further heated (step 22). That is, when it is detected that the hot water temperature detected by the hot water temperature thermistor 20 is equal to or higher than the upper limit set value (second set temperature) higher than the hot water target temperature, the hot water temperature is further increased. It is determined that the temperature has reached a sufficiently high temperature without heating, the combustion of the burner 3 is stopped (step 23), and if the temperature of the hot water is lower than the second set temperature, the temperature of the hot water is further increased. Is determined to be a person who needs to be heated, and the process returns to step 20 to wait for the start of the normal combustion or the determination that the burner 3 does not need to perform the heating operation in accordance with the rise of the hot water temperature. State. The first set temperature as the start condition for the warm combustion and the second set temperature as the stop condition are configured to be changeable based on the operation of the temperature setting switch 16, and the hot and cold water inside the device is used for the hot and cold water. The hot water is heated and kept at a temperature close to the tapping target temperature according to the purpose. Further, the predetermined temperature difference can be set and changed based on the operation of the temperature setting switch 16 so that the drop of the tap water temperature can be determined in accordance with the use environment of the tap water.

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 usually heated and kept at the hot water target temperature or a temperature close thereto. In some cases, hot water at or near the hot water target temperature will be supplied as soon as possible.In addition, if the hot water inside the hot water channel is cooled and becomes dead water, the heat retention combustion control is stopped. Thus, economical operation of the water heater can be achieved.

[Other Embodiments] (1) In the above embodiment, the first and second set temperatures set by the temperature setting switch 16 and the hot water for warming are set as ON and OFF conditions of the burner 3 in the warming combustion control. Although the difference from the temperature is used, the following configuration may be used instead of the above configuration.

When the burner 3 is turned on based on the lapse of time from the time when the burner 3 was turned off, or when the set time has passed since the time when the burner 3 was turned on, the burner 3 is automatically turned off. It may be configured to perform an OFF operation.
In such a configuration, in the former case, step 18
Instead of the determination condition based on the temperature, it may be determined whether the elapsed time since the burner 3 is turned off exceeds the set time. In the latter case, the determination condition based on the temperature in step 22 is used instead. It may be determined whether or not the elapsed time from the start of combustion exceeds the set time. In such a case, it is desirable that the set time can be changed.

In the above embodiment, the discrimination based on the temperature and the discrimination based on the passage of time may be used in combination.

(2) In the above embodiment, the water inlet 5 and the hot water outlet 6 are connected to the heat exchanger 2, respectively, 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.

As shown in FIG. 6, the water inlet 5 and the hot water outlet 6 are connected via a bypass 30, and the bypass 30 is provided with a bypass valve 31 which can be intermittently connected to the outlet of the heat exchanger 2. Outlet hot water thermistor 32 for detecting hot water temperature
And a mixed water temperature thermistor 33 for detecting the temperature of the mixed water, a state in which the bypass valve 31 is opened to supply a large amount of relatively low-temperature water, and a state in which the bypass valve 31 is closed to supply the high-temperature water. When the bypass valve 31 is opened, the amount of combustion of the burner 3 is controlled by feed-forward control based on the detected information of the outlet hot water temperature thermistor 32 and the target temperature when the bypass valve 31 is opened. Then, based on the detection information of the mixed hot water temperature thermistor 33, the combustion amount of the burner 3 is feedback-controlled so that the mixed hot water temperature becomes the target temperature. Alternatively, as shown in FIG. 7, a mixing valve 34 capable of changing and adjusting the distribution ratio is provided at the junction of the bypass path and the hot water path 6 on the heat exchanger 2 side, and the detection of the outlet hot water temperature thermistor 32 is performed in the normal combustion control. The configuration may be such that the combustion amount of the burner 3 is adjusted so that the value is maintained at a set temperature (for example, 80 ° C.), and the mixing ratio of the mixing valve 34 is adjusted and controlled so that the mixed hot water temperature becomes the target temperature. .

In such a case, it is practical to judge whether or not the temperature of the hot water in the hot water path has dropped, based on the mixed hot water temperature. Instead of using the difference between the water temperature in the water channel and the water temperature in the water channel, the difference between the mixed hot water temperature and the water temperature in the water channel is preferably used as the temperature difference in water.

(3) In the above-described embodiment, when the heat-retention combustion control is executed, the hot water in the hot water passage in the apparatus is maintained in a state where it does not flow. As shown in FIG. 8, a pump 35 that circulates and flows through the bypass passage 30 may be provided, and when the warming combustion control is executed, the pump 35 may be operated to circulate hot water. It should be noted that the circulation pump 35 may be of a small size such that hot water slightly moves in the hot water path. When applying warm combustion control to such a configuration,
The temperature of the hot and cold water circulating is regarded as the hot water temperature.

In each embodiment, the hot water temperature thermistor for measuring the hot water temperature may be provided in a pipe in which hot water which is regarded as the hot water temperature is present. Can be changed as appropriate

(4) In the above embodiment, as the normal combustion control, the burner 3 is burned in accordance with the flow of water to the heat exchanger 2, and the combustion amount of the burner 3 is adjusted so that the outlet temperature becomes the target temperature. However, instead of such a configuration,
The combustion amount of the burner 3 may be set to be constant, and a water amount adjustment valve that changes and executes the water flow amount to the heat exchanger 2 may be controlled.

(5) In the above embodiment, the user of the hot water supply device independently determines whether to perform the warming combustion control mode by providing the warming mode switch 17 or to forcibly stop the setting, and change the setting. Although it was configured to be able to
May be configured so as to always be in the warming combustion control mode without providing, and in step 3 the configured warming flag may always be passed to step 4 and subsequent steps.

[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 flowchart of a control operation.

FIG. 6 is a schematic diagram of a hot water supply device in another embodiment.

FIG. 7 is a schematic view of a hot water supply apparatus according to another embodiment.

FIG. 8 is a schematic view of a hot water supply device in another embodiment.

[Explanation of symbols]

 2 Heat Exchanger 3 Burner 5 Water Inlet 6 Hot Water Outlet 100 Normal Combustion Control Unit 101 Insulated Combustion Control Unit 102 Insulated Combustion Control Stop Unit 103 Insulated Combustion Control Start Unit

Claims (5)

[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 is provided. A hot water supply device provided with normal combustion control means for executing normal combustion control for starting combustion of the burner and stopping combustion of the burner as the flow of water is stopped. When the temperature of the hot water in the heat exchanger becomes equal to or lower than the first set temperature while the flow of water to the heat exchanger is stopped, the combustion of the burner is started, and the temperature of the hot water in the heat exchanger becomes the second temperature. (2) When the temperature becomes equal to or higher than the set temperature, a warming combustion control means for performing warming combustion control for stopping the combustion of the burner is provided, and a difference between the hot water temperature in the tap water path and the water supply temperature in the inlet water path is equal to or less than a predetermined temperature difference When the temperature becomes, the warmed combustion stops the warmed combustion control. Hot water supply device provided with control stop means. 2. 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 is provided, and water flow to the heat exchanger is started. A hot water supply device provided with normal combustion control means for executing normal combustion control for starting combustion of the burner and stopping combustion of the burner as the flow of water is stopped. In a state in which the water flow to the vessel is stopped, after a first set time has elapsed after the burner has stopped burning, a warmed combustion control means for performing a warmed combustion control for burning the burner for a second set time is provided. A hot water supply device provided with a warming / combustion control stopping means for stopping the warming / combustion control when the difference between the hot water temperature in the inside and the water supply temperature in the water inlet channel becomes equal to or less than a predetermined temperature difference; 3. A hot water supply system according to claim 1, further comprising: a bypass connecting the water inlet and the hot water outlet with bypass without passing through the heat exchanger. On the downstream side, there is provided mixed hot water temperature detecting means for detecting a mixed hot water temperature in which water from the water inlet channel and hot water on the upstream side of the junction in the hot water channel are mixed. 3. An insulated combustion control stopping means for stopping the insulated combustion control when a difference between the temperature and the water temperature becomes equal to or less than a predetermined temperature difference.
The hot water supply device according to the item. 4. The hot water supply apparatus according to claim 1, further comprising a setting change unit configured to change the setting of the predetermined temperature difference. 5. The normal combustion control is performed after the warm combustion control is stopped by the warm combustion control stopping means, and further,
The hot water supply apparatus according to any one of claims 1 to 4, further comprising a warming combustion control starting means for restarting the warming combustion control when the normal combustion control is stopped.