JP3724661B2 - Water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater, and more particularly, to a water heater that stops combustion when a tapping temperature is abnormal.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there are known water heaters that discharge hot water at a desired temperature by inputting a set temperature by an external operation. In general, such a water heater includes a burner that burns fuel gas, and a heat exchanger that heats the cold water supplied from the inlet water by the combustion heat of the burner and supplies it to the outlet water path, and is provided in the outlet water path. The temperature sensor detects the temperature of the hot water and controls the amount of combustion of the burner based on the temperature of the hot water and the set temperature input by an external operation, thereby controlling the temperature of the hot water to bring the temperature of the hot water close to the set temperature.
[0003]
[Problems to be solved by the invention]
However, if the hot water temperature control is not performed normally due to a failure of the proportional valve that adjusts the gas supply amount to the burner, a difference occurs between the set temperature and the hot water temperature, and the hot water temperature becomes significantly higher than the set temperature. If you do, there is a risk of burns. In order to solve such problems, the conventional burn prevention function is configured such that when the temperature of the hot water is higher than a preset value by a predetermined value or more and the state continues for a predetermined time or more, it is judged as abnormal and the combustion operation is stopped. Have taken. However, in order to prevent burns in such a configuration, it is necessary to shorten the predetermined time for judging an abnormality as much as possible. For example, when the set temperature is changed to a low value, when the incoming water flow rate suddenly decreases, Even if the hot water temperature is temporarily higher than the set temperature when the user performs some external operation, such as at the start of operation, the combustion operation is stopped because it is not abnormal but is abnormal. It was easy to use. Also, if the incoming water flow rate is low and the incoming water temperature is high, the hot water temperature will exceed the preset temperature even if the burner combustion amount is reduced to the minimum if the preset temperature is low. There was a problem of misunderstanding.
[0004]
An object of the present invention is to provide a water heater that solves the above-described problems and that is easy to use while preventing burns.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, a water heater according to claim 1 of the present invention comprises a burner for burning fuel gas,
A heat exchanger that heats the cold water supplied from the water supply channel by the combustion heat of the burner and supplies it to the hot water supply channel;
Temperature detecting means for detecting the temperature of the hot water in the hot water path,
Temperature setting means for setting the set temperature by external operation;
Tapping temperature control means for controlling the combustion amount of the burner so that the tapping temperature approaches the set temperature ;
A flow rate sensor for detecting a flow rate of water flowing through the water supply channel;
In the water heater provided with a combustion stop means for stopping the combustion operation when the tapping temperature is higher than a required value by the set temperature ,
The combustion stopping means includes a predetermined period after the set temperature is changed to a low level, a predetermined period after the combustion operation is started, and a predetermined period after the detection value of the flow rate sensor changes more than a predetermined value during the hot water operation. period is characterized in that those not adversely line to stop the combustion operation (first invention).
[0006]
1st invention WHEREIN: The abnormality report means which reports that it is abnormal when the combustion operation | movement is stopped by the said combustion stop means is provided, This abnormality report means is the said flow sensor when the said combustion stop means stops combustion. When the detected value is equal to or less than a predetermined value and the combustion amount of the burner is minimum, it is preferable not to report that it is abnormal (second invention).
[0009]
According to the first invention , the tapping temperature control means controls the combustion amount of the burner so that the tapping temperature approaches the set temperature. When the tapping temperature becomes higher than the set temperature by a predetermined value or more, the combustion stop means Since the combustion operation is stopped, burns can be prevented. In addition, if the set temperature is changed during combustion, the tapping temperature may temporarily exceed the set temperature and the tapping temperature may be higher than the set temperature by a predetermined value or more. Since the combustion operation is not stopped for a predetermined period after that, it is possible to prevent the combustion operation from being stopped.
[0010]
Also , when the hot water supply operation is resumed in a short time after the hot water supply operation is completed, the hot water accumulated in the heat exchanger is discharged, the hot water temperature is temporarily exceeded, and the hot water temperature is set higher than the set temperature. there can be high value or more, but the predetermined period after the start combustion operation even these cases because not adversely line to stop the combustion operation, it is possible to prevent the stopping of combustion operation.
[0011]
Furthermore , even when the incoming water temperature suddenly decreases, the tapping temperature may exceed the set temperature, and the tapping temperature may be higher than the set temperature by a predetermined value. If you change the value above, a predetermined period after the change, because not adversely line to stop the operation, it is possible to prevent the stopping of combustion operation.
[0012]
In addition, by adopting the configuration of the second aspect of the invention, when the combustion stopping means stops the combustion operation, it is safe because the abnormality notifying means notifies that it is abnormal. Even when the burner combustion amount is minimum, when the incoming water flow rate is low and the incoming water temperature is high, the tapping temperature exceeds the set temperature and the tapping temperature becomes higher than the set temperature by a predetermined value or more, so the combustion stop means burns. While stopping the operation, if yet combustion rate of the burner detection value is equal to or less than a predetermined value of the flow rate sensor is minimal, there is no I line a notification indicating that abnormal distinguish whether is by failure can do. That is, water heater according to the second invention, even if the combustion amount of burners to a minimum, in the case where the hot water temperature becomes a high temperature relative to the set temperature, without I rows abnormality notification for not unusual combustor The combustion is stopped for safety.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the water heater of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a water heater as one embodiment. The water heater includes a heat exchanger 3 to which the water supply channel 1 and the outlet channel 2 are connected, a burner 4 for heating water flowing through the heat exchanger 3, and a gas supply channel 5 for supplying gas to the burner 4. And a controller 6 for controlling the combustion control. The water supply channel 1 is provided with a flow rate sensor 7 for detecting the incoming water flow rate and an incoming water thermistor 8 for detecting the incoming water temperature. Further, a hot water thermistor 9 for detecting the temperature of the hot water is provided in the hot water outlet 2 and connected to an external hot water supply pipe 10 that leads to a hot water supply port such as a washroom and a shower on the downstream side. The gas supply path 5 is provided with a main electromagnetic valve 11 and an original electromagnetic valve 12 that open and close the flow path, and a proportional valve 13 that adjusts the amount of gas.
[0014]
The controller 6 includes a CPU, a RAM, and a ROM constituting a well-known arithmetic logic circuit (not shown), an input interface for inputting signals from various sensors, an output interface for outputting drive signals to various actuators, and the like. The controller 6 is connected with a remote controller 14 having a temperature setting switch for inputting a set temperature. Note that FIG. 1 shows the input / output relationship of only the configuration related to the burn prevention control process which is a feature of the present invention.
[0015]
In addition, the controller 6 starts simultaneously with the start of combustion, stops when 5 seconds have elapsed, and resets the combustion start timer, and a decrease in the incoming water flow rate by a predetermined value or more (in this embodiment, a flow rate decrease of 3 liters / minute or more in 2 seconds) ) Is detected, and when the set temperature at that time is 46 ° C or lower, it stops when 5 seconds have elapsed, and when it is higher than 46 ° C, it stops when 20 seconds have elapsed. Starts when the temperature is changed from higher than 50 ° C to 50 ° C or lower, and the tapping temperature becomes 53 ° C or lower or stops when 15 seconds have elapsed, and resets the setting change timer A and the set temperature is higher than 50 ° C Starts when the temperature is changed to 50 ° C or less, and stops and resets when the tapping temperature falls below the set temperature + 10 ° C or when 15 seconds have elapsed. And a change timer B. In addition, when the water is stopped during the timer operation, the combustion start timer and the flow rate timer are stopped and reset simultaneously with the water stop, but the setting change timer A and the setting change timer B are stopped simultaneously with the water stop but are reset. Instead, it continues to count during reburning. Therefore, when the set temperature is changed from 50 ° C. or more to 50 ° C. or less when the water is stopped, the setting change timer A and the setting change timer B are started simultaneously with the start of combustion. However, it is reset when the water stop state continues for 2 hours.
[0016]
Although not shown, the water heater includes an ignition device for igniting the burner 4, a flame detection device for detecting the flame of the burner 4, a fan for supplying combustion air, and the like.
[0017]
Next, the burn prevention control process performed by the controller 6 will be described with reference to the flowchart of FIG. When the set temperature is changed from a temperature higher than 50 ° C. to 50 ° C. or lower by a remote control operation before the combustion operation (S1: YES), the setting change timers A and B are each in a standby state for starting simultaneously with the start of combustion. (S2). When a predetermined combustion start flow rate is detected by the flow rate sensor 7 (S3), the burner 4 is ignited by an ignition device (not shown) (S4), and when a flame is detected by a flame detection device (not shown), the combustion start timer is set to 5 seconds. Is started (S5). If the setting change timers A and B are in the standby state (S6: YES), the count is started simultaneously (S7).
[0018]
When the burner 4 starts to burn, the gas is continuously changed by the proportional valve 13 according to the difference between the hot water temperature detected by the hot water thermistor 9 and the set temperature set by the remote control operation, and the hot water temperature is set to the set temperature. The hot water temperature is controlled so as to be close to (S8). Here, when the flow rate sensor 7 detects a decrease in the incoming water flow rate that is greater than or equal to a predetermined value (in this embodiment, a flow rate decrease of 3 liters / minute or more in 2 seconds) (S9: YES), when the set temperature is 46 ° C. or less. (S10: YES) The flow rate timer starts counting for 5 seconds (S11), and when the set temperature is higher than 46 ° C. (S10: NO), the flow rate timer starts counting for 20 seconds (S12). When the incoming water flow rate is equal to or lower than the combustion stop flow rate (2.5 liters / minute in this embodiment) (S13), the main electromagnetic valve 11 and the original electromagnetic valve 12 are closed to stop the combustion operation, The post-purge operation is performed by the fan that does not (S14). Further, the combustion start timer and the flow rate timer are stopped and reset (S15), and the setting change timers A and B are stopped (S16). When the set temperature is changed from a temperature higher than 50 ° C. to 50 ° C. or lower during the hot water operation (S17: YES), the setting change timers A and B are started (S18).
[0019]
Next, the set temperature is checked for burn prevention control. When the set temperature is higher than 50 ° C. (S19: NO), it can be determined that the user is aware that the hot water temperature is high. Therefore, when the tapping temperature is higher than the set temperature by 20 ° C. or more (S20: YES), when the state continues for 10 seconds (S21), the routine proceeds to the combustion stop control (B). In the combustion stop control, after closing the main solenoid valve 11 and the original solenoid valve 12 to stop the combustion of the burner 4 (S22), the incoming water flow rate is equal to or less than a predetermined value near the combustion stop flow rate at which the combustion operation is stopped (in this embodiment). 3 liters / minute or less), and whether or not the condition that the proportional valve opening is minimum is checked (S23). If this condition is met (S23: YES), the hot water temperature is considered to have increased due to a high water temperature, so that no abnormality notification is given and the water flow rate during normal use is the combustion stop flow rate (2.5%). In the same manner as in the case of less than (liter / minute), a post-purge operation is performed by a fan (not shown) (S24). Here, when the incoming water flow rate is increased by 1.6 liters / minute or more from the flow rate at the time when combustion is stopped (S25: YES), reignition is performed (E). Further, when the incoming water flow rate is reduced below the combustion stop flow rate (2.5 liters / minute) (S26: YES), the same control as in the normal water stop state is performed (F). On the other hand, if the condition is not satisfied in step 23, it is determined that an abnormality has occurred (S23: NO), and the fact that an abnormality has occurred is notified by the buzzer and display of the remote controller 14 (S27). Further, after purge for a predetermined time (10 seconds in this embodiment) is performed (S28).
[0020]
Moreover, in step 19, when preset temperature is 50 degrees C or less (S19: YES), it is possible that a user touches hot water consciously. Here, the hot water temperature is checked, and if the hot water temperature is higher than the set temperature by 20 ° C. or more (S20: YES), it is checked whether the setting change timer B is operating (S30). When the setting change timer B is in operation (S30: YES), it is considered that the change has occurred temporarily due to a change in the set temperature, so that the combustion operation is stopped because it can be predicted by the user. Absent. However, if the setting change timer B is not activated, the routine proceeds to the combustion stop control described above (B), and the combustion is immediately stopped (S22).
[0021]
In step 29, even if the tapping temperature is not higher than 20 ° C. compared to the set temperature (S29: NO), it is checked whether the tapping temperature is higher than 59 ° C. (S31). Here, when the tapping temperature is higher than 59 ° C. (S29: NO), it is first checked whether or not the combustion start timer is operating (S32). When the combustion start timer is operating (S32: YES), it is considered that the temperature has risen temporarily at the start of combustion. Therefore, the combustion operation is not stopped because it can be predicted by the user. However, if the combustion start timer is not operating (S32: NO), it is checked whether the flow rate timer is operating (S33). Here, when the flow rate timer is operating (S33: YES), it is considered that this is a temporary rise in the temperature of the hot water due to a decrease in the flow rate, so that the combustion operation is not stopped because it can be predicted by the user. However, if the flow rate timer is not operating (S33: NO), it is checked whether the setting change timer A is operating (S34). Here, when the setting change timer A is operating (S34: YES), it is considered that it is due to the change of the set temperature, and therefore the combustion operation is not stopped because it can be predicted by the user. . However, when the setting change timer A is not activated (S34: NO), all three timers are not activated, so the routine proceeds to the combustion stop control described above (B), and the combustion is immediately stopped. (S22).
[0022]
As described above, according to the hot water supply apparatus of this embodiment, when the set temperature is higher than 50 ° C., it is considered that the user is consciously using the hot water temperature in advance. Even if the temperature is higher than the set temperature by 20 ° C or more, the combustion is not stopped immediately, and the combustion operation is stopped after the state continues for 10 seconds. It is easy to use in order to prevent it from stopping, and since it is considered that the state will continue for 10 seconds or more when an abnormality occurs, the combustion operation is stopped and it is safe. In addition, when the set temperature is 50 ° C. or less, it is considered that the user consciously touches the hot water. Therefore, when the tapping temperature is higher than the set temperature by 20 ° C. or more, except when the setting change timer B is activated. It is safe because it immediately stops the combustion operation, and if the tapping temperature is temporarily higher than the set temperature due to a change in the set temperature, the tapping temperature will be temporarily higher than the set temperature by 20 ° C or more. Since the combustion operation is not stopped, it is easy to use. Even when the set temperature is 50 ° C. or less and the tapping temperature is not higher than 20 ° C. compared to the set temperature, the tapping temperature is higher than 59 ° C., and all of the combustion start timer, flow rate timer, and setting change timer A If it is not working, it is safe to stop the combustion operation immediately after judging that it is abnormal, and it is safe when the hot water supply operation is restarted in a short time after the hot water supply operation is completed, or when the incoming water flow rate suddenly decreases. When the temperature of the hot water can be temporarily raised above 59 ° C., such as when the temperature is changed to low, the combustion operation is not stopped by the operation of the timer, which is convenient. Also, when the combustion operation is stopped to prevent burns, if the incoming water flow rate is close to the minimum flow rate at which hot water supply operation is performed and the opening of the proportional valve 13 is minimum, the hot water temperature increases when the incoming water temperature is high. Since there is no possibility of anomaly notification, it is easy to use, and since the re-ignition does not occur until the incoming water flow rate increases 1.6 liters / minute or more from the incoming water flow rate when the combustion operation is stopped, the tapping temperature after re-ignition Can be brought close to the set temperature. In addition, since the setting change timers A and B continue after the water stoppage, the combustion operation is not stopped even if a high temperature hot water is discharged due to a change in the set temperature at the start of combustion, which is convenient and the setting change timers A and B are in operation. Even if an abnormality occurs and the hot water temperature does not drop, it is safe to stop and reset in a maximum of 15 seconds after the set temperature change. In addition, since the count time of the flow rate timer differs depending on the set temperature, both safety and usability can be achieved. In addition, when the combustion operation is stopped due to an abnormality, the abnormality is notified so that the user can be immediately notified that the abnormality has occurred, and the after purge operation is performed safely.
[0023]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the present invention may be used for a bath water heater and the like, and various embodiments are possible without departing from the gist of the present invention. Of course, it can be implemented.
[0024]
【The invention's effect】
As described above in detail, according to the water heater according to the first invention, by not adversely line to stop for a predetermined period combustion operation after the set temperature was changed less during combustion temporarily by setting the temperature change in the case where the hot water temperature exceeds the set temperature, usability for the combustion operation is determined that the abnormality can prevent you stopped is not good. In addition, when the hot water temperature becomes higher than the set temperature by a predetermined value or more due to a failure or the like, the combustion operation is immediately stopped, which is safe.
[0025]
Also, by not adversely line to stop the burning operation predetermined time after the start of the combustion operation, and resume in a short time hot water supply operation from the end of the hot water supply operation, the like if the hot water temperature becomes temporarily high, usability to prevent it is determined that abnormality occurs resulting in stopping the combustion operation is not good.
[0026]
Further, when the detected value of the flow rate sensor which by not adversely line to stop for a predetermined period combustion operation after the change more than a predetermined value within a predetermined time period, temporary hot water temperature by the flow rate reduction is increased, abnormal usability for the combustion operation determines it is possible to prevent the stop and is not good.
[0027]
Then, according to the water heater according to the second invention, when yet combustion rate of the burner detection value is equal to or less than a predetermined value of the flow rate sensor is minimum, by not adversely line a notification indicating that abnormal, Since the incoming water flow rate is small and the incoming water temperature is high, it is possible to prevent the abnormality from being determined when the hot water temperature increases even when the burner combustion amount is minimized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a water heater as one embodiment.
FIG. 2 is a flowchart showing burn prevention control processing of the present embodiment.
FIG. 3 is a flowchart showing burn prevention control processing of the present embodiment.
FIG. 4 is a flowchart showing burn prevention control processing of the present embodiment.
[Explanation of symbols]
1 ... water supply channel, 2 ... hot water supply channel, 3 ... heat exchanger, 4 ... burner,
5 ... Gas supply path, 6 ... Controller, 7 ... Flow rate sensor,
8 ... Incoming thermistor, 9 ... Hot water thermistor, 10 ... External hot water supply pipe,
DESCRIPTION OF SYMBOLS 11 ... Main solenoid valve, 12 ... Original solenoid valve, 13 ... Proportional valve, 14 ... Remote control.

Claims (2)

A burner that burns fuel gas;
A heat exchanger that heats the cold water supplied from the water supply channel by the combustion heat of the burner and supplies it to the hot water supply channel;
Temperature detecting means for detecting the temperature of the hot water in the hot water path,
Temperature setting means for setting the set temperature by external operation;
Tapping temperature control means for controlling the combustion amount of the burner so that the tapping temperature approaches the set temperature ;
A flow rate sensor for detecting a flow rate of water flowing through the water supply channel;
In the water heater provided with a combustion stop means for stopping the combustion operation when the tapping temperature is higher than a required value by the set temperature ,
The combustion stop means includes a predetermined period after the set temperature is changed to a low level, a predetermined period after the combustion operation is started, and a predetermined period after the detected value of the flow rate sensor changes more than a predetermined value during the hot water operation. period, water heater, characterized in that is not conducted to stop the combustion operation. An abnormality report unit is provided for reporting an abnormality when the combustion operation is stopped by the combustion stop unit, and the abnormality report unit has a detection value of the flow rate sensor predetermined when the combustion stop unit stops the combustion. The hot water heater according to claim 1, wherein when the burner burns below the value and the combustion amount of the burner is the minimum, no report of an abnormality is made .

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