JP5030905B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus having a function of detecting abnormality of a temperature sensor.

  The hot water supply apparatus is provided with a temperature sensor such as a hot water supply temperature sensor for detecting the temperature of hot water supplied from the hot water supply pipe in order to control the hot water supply temperature. For example, when the harness connecting the temperature sensor and the control board is partially short-circuited or disconnected, the level of the detection signal from the temperature sensor increases or decreases, causing a gap between the detected temperature and the actual temperature. There is. In this case, the hot water supply temperature cannot be accurately controlled.

  Therefore, conventionally, a hot water supply apparatus having a function of detecting an abnormality of a hot water supply temperature sensor is known (for example, see Patent Documents 1 and 2).

  The hot water supply apparatus described in Patent Document 1 has a function of filling a bathtub with a hot water, and when hot water is filled, the hot water supply heat exchanger is used to pass through a hot water supply pipe and a circulation circuit for reheating. Then hot water is supplied to the bathtub. During the hot water filling, the temperature difference between the detected temperature of the hot water thermistor 6 that detects the temperature of hot water supplied to the hot water supply pipe and the detected temperature of the bath thermistor provided in the circulation circuit is equal to or higher than a predetermined temperature. When this happens, it is determined that the hot water temperature sensor or bath temperature sensor is in an abnormal state.

Moreover, in the hot water supply apparatus described in Patent Document 2, a certain amount of time (two hours or more) has elapsed since the hot water supply stopped, and the temperature of the water retained in the hot water supply apparatus has dropped to a uniform temperature. Waiting to become. In this state, the temperature difference between the detected temperature of the hot water temperature thermistor that detects the temperature of the hot water supplied from the hot water supply device and the detected temperature of the supplied water temperature thermistor that detects the temperature of the supplied water is a predetermined temperature ( When the temperature is 5 ° C. or higher, it is determined that the hot water temperature thermistor or the feed water thermistor is in an abnormal state.
JP-A-9-44257 Japanese Patent Laid-Open No. 11-316029

  The abnormality detection of the temperature sensor by the hot water supply device of Patent Document 1 described above is based on the premise of a configuration having a hot water filling function, and thus has a disadvantage that it cannot be applied to a hot water supply device having no hot water filling function. Further, since the temperature sensor abnormality can be detected only when the hot water is filled, there is an inconvenience that the temperature sensor abnormality cannot be detected when hot water is used for other purposes.

  In addition, since the temperature sensor abnormality detection by the hot water supply apparatus of Patent Document 2 described above is based on the premise that the hot water supply is stopped for a considerably long time, the abnormality of the temperature sensor is frequently caused under the situation where hot water is frequently used. When this occurs, there is an inconvenience that an abnormality of the temperature sensor cannot be detected.

  Therefore, an object of the present invention is to provide a hot water supply device that can detect the abnormality of the temperature sensor quickly by increasing the frequency of determining whether the abnormality of the temperature sensor is present.

  The present invention has been made to achieve the above object, and is connected to a water supply pipe and a hot water supply pipe, heats the water supplied from the water supply pipe, and discharges the hot water to the hot water supply pipe, Heating means for heating the heat exchanger; bypass pipe for bypassing the heat exchanger to communicate the water supply pipe and the hot water supply pipe; and bypass pipe opening changing means for changing the opening of the bypass pipe; A heat exchanger temperature sensor for detecting the temperature of hot water discharged from the heat exchanger, a hot water supply temperature sensor for detecting the temperature of hot water supplied to the downstream side of the junction with the bypass pipe of the hot water pipe, and A water flow sensor for detecting water supplied from the water supply pipe to the heat exchanger, and detection by the hot water supply temperature sensor when water supplied from the water supply pipe to the heat exchanger is detected by the water flow sensor. The temperature of the hot water to be As the hot water temperature, an improvement of the water heater with a hot water supply control means for executing the hot water supply operation for controlling the heating amount of said heating means.

  When the hot water supply operation is performed, when the temperature detected by the heat exchange temperature sensor is equal to or lower than the target hot water temperature, the bypass pipe is changed to the fully closed state by the bypass pipe opening changing means, and the fully closed When the temperature difference between the detected temperature of the heat exchange temperature sensor and the detected temperature of the water supply temperature sensor in the state becomes equal to or higher than a first predetermined temperature, the heat exchange temperature sensor or the hot water supply temperature sensor enters an abnormal state There is provided a temperature sensor abnormality detecting means for detecting that it is present.

  In the present invention, when water is supplied from the water supply pipe to the hot water supply pipe via the bypass pipe, hot water discharged from the heat exchanger and water supplied from the bypass pipe are mixed, Supplied from a hot water pipe. In this way, when the water is circulated from the bypass pipe to the state where the bypass pipe is fully closed and the supply of water from the bypass pipe to the hot water supply pipe is stopped, the hot water supplied from the hot water supply pipe is changed. The temperature rises. However, when the temperature of the hot water discharged from the heat exchanger is equal to or lower than the target hot water supply temperature, the temperature of the hot water supplied from the hot water supply pipe is not reduced even if the supply of water from the bypass pipe to the hot water supply pipe is stopped in this way. The possibility of becoming higher than the target hot water supply temperature is reduced.

  Therefore, the temperature sensor abnormality detection means causes the bypass pipe opening changing means to cause the bypass pipe to change when the temperature detected by the heat exchange temperature sensor is lower than the target hot water supply temperature by the first predetermined temperature or more. Fully closed. Thereby, only the hot water discharged from the heat exchanger is supplied to the hot water supply pipe while suppressing the hot water supply temperature from the hot water supply pipe from exceeding the target hot water supply temperature and giving the user an uncomfortable feeling. it can.

  And in the state where only hot water discharged from the heat exchanger is supplied to the hot water supply pipe in this way, when the heat exchange temperature sensor or the hot water supply temperature sensor is abnormal, it is the same if it is normal. A difference occurs between the temperature detected by the heat exchanger temperature sensor and the temperature detected by the hot water temperature sensor. Therefore, the temperature sensor abnormality detection means, when a temperature difference between the detection temperature of the heat exchange temperature sensor and the detection temperature of the hot water supply temperature sensor is equal to or higher than the first predetermined temperature, It can be detected that the hot water temperature sensor is in an abnormal state.

  At the start of the hot water supply operation, if a certain amount of time has passed since the previous stop of the hot water supply operation, the temperature detected by the heat exchange temperature sensor can be expected to be lower than the target hot water supply temperature. Even in a situation where execution and stop are frequently switched, the temperature sensor abnormality detection means can detect an abnormality in the heat exchange temperature sensor and the hot water supply temperature sensor. Therefore, the temperature sensor abnormality detection means can quickly detect the occurrence of abnormality in the heat exchange temperature sensor and the hot water supply temperature sensor, and can take measures such as abnormality notification and prohibition of hot water supply operation.

  Further, when the hot water supply operation is started by the hot water supply control means, when the detected temperature of the heat exchange temperature sensor is equal to or lower than a second predetermined temperature higher than the target hot water supply temperature, the opening of the bypass pipe is changed. A bypass pipe opening control means for performing a hot water temperature rise process for reducing the opening of the bypass pipe by means to increase the rate of increase in the temperature of hot water discharged from the heat exchanger, and detecting the temperature sensor abnormality When the temperature of the hot water temperature sensor is equal to or lower than the target hot water supply temperature when the hot water temperature rise process is executed, the bypass pipe opening degree changing means causes the bypass pipe to be fully closed. When the temperature difference between the detected temperature of the heat exchanger temperature sensor and the detected temperature of the feed water temperature sensor in the fully closed state is equal to or higher than the first predetermined temperature, the heat exchanger temperature sensor or the front Hot water supply temperature sensor and detecting a an abnormal state.

  According to the present invention, the temperature of the hot water staying in the heat exchanger is higher than the target hot water supply temperature when starting the hot water supply operation after a certain amount of time has elapsed since the end of the previous hot water supply operation. When the temperature is lower than the second predetermined temperature, the temperature of hot water supplied from the hot water supply pipe is reduced by executing the hot water temperature raising process for reducing the opening degree of the bypass pipe by the bypass pipe opening degree changing means. Can be raised promptly.

  In this way, when the opening degree of the bypass pipe is reduced by the hot water temperature rise process, the opening degree of the bypass pipe is further reduced and supplied from the hot water supply pipe even if the opening degree is fully closed. The variation in the temperature of the hot water is reduced. Therefore, the uncomfortable feeling given to the user due to fluctuations in the temperature of the supplied hot water can be reduced. Therefore, the temperature sensor abnormality detection means sets the bypass pipe in a fully closed state when the temperature detected by the heat exchange temperature sensor is equal to or lower than the second predetermined temperature during the execution of the tapping temperature rise process. To do.

  Then, by further suppressing fluctuations in the temperature of hot water supplied to the hot water supply pipe when the bypass pipe is fully closed, an abnormality in the heat exchange temperature sensor and the hot water supply temperature sensor is detected. Can do.

  Embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows an overall configuration of a hot water supply apparatus according to the present embodiment. The hot water supply apparatus includes a heat exchanger 3 connected to a water supply pipe 1 and a hot water supply pipe 2, and a gas burner 4 that heats the heat exchanger 3. (Corresponding to the heating means of the present invention), bypass pipe 5 bypassing heat exchanger 3 and communicating water supply pipe 1 and hot water supply pipe 2 and the opening degree of bypass pipe 5 is adjusted to bypass ratio (heat exchanger 4, a ratio of the flow rate of water flowing through the bypass pipe to the flow rate of water flowing through 4) (corresponding to the bypass pipe opening changing means of the present invention), from the water supply pipe 1 to the heat exchanger 3. A flowing water sensor 7 for detecting the presence or absence of supplied water, a heat exchanger temperature sensor 8 for detecting the temperature T 1 of hot water near the outlet of the heat exchanger 3, and a downstream side of the connection point X between the hot water supply pipe 2 and the bypass pipe 5. Hot water temperature sensor for detecting the temperature T2 of hot water in the hot water pipe 2 It is equipped with a door.

  The flowing water detection signal from the flowing water sensor 7 and the temperature detection signals from the heat exchanger temperature sensor 8 and the hot water supply temperature sensor 9 are input to a controller 20 which is an electronic unit composed of a microcomputer (not shown). Further, the combustion amount of the gas burner 4 and the opening degree of the bypass pipe 5 are controlled by a control signal output from the controller 20.

  By causing the microcomputer of the controller 20 to execute the control program for the hot water supply device, the microcomputer functions as the hot water supply control means 21, the bypass pipe opening degree control means 22, and the temperature sensor abnormality detection means 23. The controller 20 is connected to a remote controller 30 that includes a switch for setting a target hot water supply temperature, a display unit that indicates an operating state of the hot water supply device, and the like.

  The hot water supply control means 21 executes a hot water supply operation for controlling the combustion amount of the gas burner 4 so that the temperature of the hot water supplied from the hot water supply pipe 2 becomes the target hot water supply temperature set by the remote controller 30. The bypass pipe opening control means 22 is used when the detected temperature T1 of the heat exchange temperature sensor 8 is equal to or lower than the target hot water supply temperature Ta + 3 ° C. until 10 seconds elapse after the hot water supply operation is started (heat exchanger 3). The temperature of the hot water discharged from the heat exchanger 3 is reduced by reducing the opening of the bypass pipe 5 (by reducing the bypass ratio) in the cold start state in which the hot water supply operation is started with the temperature of the hot water remaining in The hot water temperature rising process is performed to increase the rate of increase in the temperature.

  Next, the operation of the hot water supply apparatus will be described according to the flowcharts shown in FIGS. STEP 20 in FIG. 3 branched from STEP 1 to STEP 3 and STEP 2 in FIG. 2 is processing by the hot water supply control means 21.

  The hot water supply control means 21 determines whether or not the hot water supply device is in an operating state in STEP 1. The operation state is a state in which a hot water supply operation is possible, and an operation state and a standby state in which the hot water supply operation is disabled are switched by an operation of an operation switch (not shown) provided in the remote controller 30.

  When the hot water supply device is in the operating state, the process proceeds to STEP2, and when the hot water supply device is not in the operating state, the process branches to STEP3. In STEP 2, the hot water supply control means 21 determines whether or not water is being supplied from the water supply pipe 1 to the heat exchanger 3 from the detection signal of the flowing water sensor 7. When water is supplied from the water supply pipe 1 to the heat exchanger 3, the process branches to STEP 20 in FIG. 3, and the hot water supply control means 21 performs an ignition process for the gas burner 4 and starts a hot water supply operation. When the hot water supply operation has already started, the hot water supply operation is continued.

  On the other hand, when the water supply pipe 1 is not supplying water to the heat exchanger 3 in STEP 2, the process proceeds to STEP 3, and the hot water supply control means 21 extinguishes the gas burner 4 and stops the hot water supply operation when executing the hot water supply operation. .

  The subsequent STEP 10 to STEP 11 branched from STEP 4 to STEP 5 and STEP 5 are processes by the temperature sensor abnormality detection means 23. The temperature sensor abnormality detection means 23 determines whether or not 60 minutes have passed since the water supply from the water supply pipe 1 to the heat exchanger 3 was stopped in STEP4. Here, when 60 minutes have passed since the supply of water from the water supply pipe 1 to the heat exchanger 3 has stopped, the hot water remaining in the heat exchanger 3 and the hot water supply pipe 2 is sufficiently cooled naturally, and the heat exchanger 3 and the temperature of the hot water staying in the hot water supply pipe 2 are assumed to be uniform.

  Therefore, in STEP 4, when 60 minutes have passed since the water supply from the water supply pipe 1 to the heat exchanger 3 has stopped, the process proceeds to STEP 5, where the temperature sensor abnormality detection means 23 detects the temperature detected by the heat exchanger temperature sensor 8. It is determined whether or not the temperature difference (| T1−T2 |) between T1 and the detected temperature T2 of the hot water supply temperature sensor 9 is equal to or higher than a first predetermined temperature ΔTe (for example, 10 ° C.).

  When the temperature difference between the detected temperature T1 of the heat exchanger temperature sensor 8 and the detected temperature T2 of the hot water supply temperature sensor 9 is not less than the first predetermined temperature ΔTe (ΔTe ≦ | T1−T2 |), the heat exchanger temperature sensor 8 and hot water temperature sensor 9 can be determined to be in an abnormal state. Therefore, in this case, the process branches to STEP 10, and the temperature sensor abnormality detection means 23 displays an error display on the display unit (not shown) of the remote controller 30 indicating that the heat exchanger temperature sensor 8 or the hot water supply temperature sensor 9 is in an abnormal state. And at the same time prohibiting the hot water operation. Then, proceeding to STEP 11, the temperature sensor abnormality detection means 23 ends the process.

  In STEP 4, when 60 minutes have not passed since the supply of water from the water supply pipe 1 to the heat exchanger 3 has stopped, the temperature of the hot water in the heat exchanger 3 and the hot water supply pipe 2 has not been made uniform. Since the abnormality of the heat exchanger temperature sensor 8 and the hot water supply temperature sensor 9 cannot be detected, the process returns to STEP1.

  In STEP 5, when the temperature difference between the detected temperature T1 of the heat exchanger temperature sensor 8 and the detected temperature T2 of the hot water supply temperature sensor 9 is smaller than the first predetermined temperature ΔTe (ΔTe> | T1-T2 |), the heat Since it can be determined that the alternating temperature sensor 8 and the hot water supply temperature sensor 9 are operating normally, the process returns to STEP 1.

  Next, STEP 21 to STEP 23 and STEP 30 to STEP 31 in FIG. 3 are processes by the temperature sensor abnormality detection means 23. The temperature sensor abnormality detection means 23 is STEP21, and the detected temperature T1 of the heat exchanger temperature sensor 8 is equal to or lower than the target hot water supply temperature Ta + 3 ° C. (Ta + 3 ° C. corresponds to the second predetermined temperature of the present invention). It is determined whether the elapsed time from the start of operation is within 10 seconds.

  Here, the condition of STEP21 is a condition in which the above-described hot water temperature rising process is executed by the bypass pipe opening degree control means 22, and when the condition of STEP21 is satisfied, the bypass hot water temperature increasing process is executed. The ratio is set small. Therefore, in this case, even if the bypass pipe 5 is fully closed, the temperature variation of the hot water supplied from the hot water supply pipe 2 is small.

  Therefore, when the condition of STEP 21 is established, the process proceeds to STEP 22 where the temperature sensor abnormality detection means 23 causes the bypass pipe 5 to be fully closed by the bypass mixing unit 6. Thereby, while suppressing the fluctuation | variation of the temperature of the hot water supplied from a hot water supply pipe | tube, the temperature of the hot water which distribute | circulates the hot water supply pipe | tube 2 can be made uniform.

  In the next STEP 23, the temperature sensor abnormality detection means 23 determines that the temperature difference (| T1−T2 |) between the detected temperature T1 of the heat exchanger temperature sensor 8 and the detected temperature T2 of the hot water supply temperature sensor 9 is the first predetermined temperature. When the state of ΔTe or more continues for 5 seconds or more, it is determined that the heat exchanger temperature sensor 8 or the hot water supply temperature sensor 9 is in an abnormal state, and the process branches to STEP 10 in FIG.

  Note that, in STEP23, the continuation of 5 seconds or more is based on the condition that the heat exchanger temperature sensor 8 or the hot water supply temperature sensor 9 is in an abnormal state due to an instantaneous fluctuation of the temperature of hot water discharged from the heat exchanger 3. This is to prevent erroneous detection.

  In STEP 10, as described above, the temperature sensor abnormality detection means 23 performs an error display on the display unit of the remote controller 30 to indicate that the heat exchanger temperature sensor 8 or the hot water supply temperature sensor 9 is in an abnormal state, and performs the hot water supply operation. Prohibit execution. Further, when the condition of STEP23 is not satisfied, the process proceeds to STEP1 of FIG.

  If the condition of STEP 21 is not satisfied, the process branches to STEP 30, and the temperature sensor abnormality detection means 23 determines whether or not the detected temperature T1 of the heat exchanger temperature sensor 9 is equal to or lower than the target temperature Ta. Here, when the detected temperature T1 of the heat exchanger temperature sensor 9 is equal to or lower than the target hot water supply temperature Ta, the temperature of the hot water supplied from the hot water supply pipe 2 when the bypass pipe is fully closed (bypass ratio 0) is the target hot water supply temperature. It can be expected that the possibility of exceeding Ta will be low.

  Therefore, the temperature sensor abnormality detection means 23 branches to STEP 22 when the detected temperature T1 of the heat exchanger temperature sensor 9 is equal to or lower than the target temperature Ta in STEP30. And as above-mentioned, the bypass pipe 5 is fully closed and the presence or absence of abnormality of the heat exchanger temperature sensor 8 and the hot water supply temperature sensor 9 is detected.

  On the other hand, when the detected temperature T1 of the hot water supply temperature sensor 8 is higher than the target hot water supply temperature Ta in STEP 30 (Ta <T1), if the bypass pipe 5 is fully closed, the temperature of the hot water supplied from the hot water supply pipe 2 is increased. There is a high possibility that the temperature will be higher than the target hot water supply temperature Ta and give the user a sense of discomfort. Therefore, in this case, the process returns to STEP 1 in FIG. 1, and the temperature sensor abnormality detection means 23 does not perform the process of detecting the abnormality of the heat exchanger temperature sensor 8 and the hot water supply temperature sensor 9 with the bypass pipe 5 fully closed.

  In the present embodiment, the hot water temperature raising process is executed by the bypass pipe opening degree control means 22, but the effect of the present invention can be obtained even when the hot water temperature raising process is not executed.

  Further, in the present embodiment, when the hot water supply operation is being executed, in STEP21 of FIG. 3, “the detected temperature T1 of the heat exchanger temperature sensor 8 is within the target hot water supply temperature Ta + 3 ° C. within 10 seconds from the start of the hot water supply operation. ”And“ when the detected temperature T1 of the heat exchanger temperature sensor 8 is the target hot water supply temperature Ta ”in STEP 30, the process proceeds to STEP 22, the bypass pipe is fully closed, and the heat exchanger temperature is determined in STEP 23. The presence or absence of abnormality of the sensor 8 and the hot water supply temperature sensor 9 was detected. However, only when the condition of STEP 30 is satisfied, the effect of the present invention can be obtained even when the bypass pipe 5 is fully closed and the presence / absence of the heat exchange temperature sensor 8 and the hot water supply temperature sensor 9 is detected.

  In the present embodiment, the bypass mixing unit 6 capable of arbitrarily changing the bypass ratio is used as the bypass valve opening changing means of the present invention. However, an open / close valve for opening and closing the bypass pipe 5 (fully opened / closed) is used. It may be used.

  Further, in the present embodiment, the hot water supply apparatus using the gas burner 4 as the heating means of the present invention is shown, but the present invention is also applied to a hot water supply apparatus using other types of heating means such as a kerosene burner and an electric heater. Can be applied.

The whole hot-water supply apparatus block diagram of this invention. The operation | movement flowchart of the hot-water supply apparatus shown in FIG. Operation flowchart of the hot water supply apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Water supply pipe, 2 ... Hot water supply pipe, 3 ... Heat exchanger, 4 ... Gas burner (heating means), 5 ... Bypass pipe, 6 ... Bypass mixing unit (bypass pipe opening change means), 7 ... Flow sensor, 8 ... Heat exchange temperature sensor, 9 ... Hot water supply temperature sensor, 20 ... Controller, 21 ... Hot water supply control means, 22 ... Bypass pipe opening control means, 23 ... Temperature sensor abnormality detection means

Claims (2)

A heat exchanger connected to a water supply pipe and a hot water supply pipe to heat the water supplied from the water supply pipe and discharge the hot water to the hot water supply pipe;
Heating means for heating the heat exchanger;
A bypass pipe that bypasses the heat exchanger and communicates the water supply pipe and the hot water supply pipe;
A bypass pipe opening changing means for changing the opening of the bypass pipe;
A heat exchanger temperature sensor for detecting the temperature of hot water discharged from the heat exchanger;
A hot water supply temperature sensor for detecting the temperature of hot water supplied to the downstream side of the joining point of the hot water supply pipe and the bypass pipe;
A flowing water sensor for detecting water supplied from the water supply pipe to the heat exchanger;
When the water supplied from the water supply pipe to the heat exchanger is detected by the flowing water sensor, the heating means is configured so that the temperature of the hot water detected by the hot water supply temperature sensor becomes a predetermined target hot water temperature. In a hot water supply apparatus comprising a hot water supply control means for executing a hot water supply operation for controlling the heating amount of
During the hot water supply operation, when the temperature detected by the heat exchange temperature sensor is equal to or lower than the target hot water supply temperature, the bypass pipe opening degree changing means is used to fully close the bypass pipe, and in the fully closed state, When the temperature difference between the detected temperature of the heat exchange temperature sensor and the detected temperature of the water supply temperature sensor is equal to or higher than a first predetermined temperature, the heat exchange temperature sensor or the hot water supply temperature sensor is in an abnormal state. A hot water supply apparatus comprising temperature sensor abnormality detection means for detecting. The hot water supply device according to claim 1,
When the hot water supply operation is started by the hot water supply control means, and the detected temperature of the heat exchange temperature sensor is equal to or lower than a second predetermined temperature higher than the target hot water supply temperature, the bypass pipe opening degree changing means Comprising a bypass pipe opening degree control means for performing a hot water temperature rise process for reducing the opening degree of the bypass pipe and increasing the rate of increase in the temperature of hot water discharged from the heat exchanger;
The temperature sensor abnormality detecting means is configured to cause the bypass pipe opening changing means to change the bypass pipe when the detected temperature of the heat exchange temperature sensor is equal to or lower than the target hot water supply temperature during execution of the hot water temperature rising process. When the temperature difference between the detected temperature of the heat exchanger temperature sensor and the detected temperature of the feed water temperature sensor in the fully closed state is equal to or higher than the first predetermined temperature, the heat exchanger temperature sensor Alternatively, the hot water supply apparatus detects that the hot water temperature sensor is in an abnormal state.

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