JP5918204B2 - Water heater - Google Patents

Description

  The present invention includes a water heater provided with a heating means and a water passage that communicates a water supply pipe and a hot water discharge pipe through a heat exchanger heated by the heating means, and a water temperature detection means is disposed in a part of the water passage. About.

  Conventionally, as this type of water heater, according to Patent Document 1, an air temperature detecting means is arranged, a portion of a water passage between the heat exchanger and the water supply pipe, and a water passage between the heat exchanger and the hot water pipe. There is known a device in which a heater is disposed in the portion. In this case, when the temperature detected by the air temperature detecting means becomes equal to or lower than a predetermined reference temperature in a state where the operation of the water heater is stopped, the heater is operated to prevent the water passage from freezing.

  By the way, if the temperature detection means is disconnected or short-circuited, it can be judged that the resistance value has become very small or large, but it can be judged that the failure has occurred. Can not. In this case, in the above conventional example, even when the actual air temperature is not lower than the predetermined reference temperature, the temperature detected by the air temperature detecting means is lower than the reference temperature, and the heater is operated unnecessarily. This wastes energy.

Japanese Patent Laid-Open No. 9-229477

  In view of the above points, the present invention provides a water heater that can suppress energy from being wasted due to the temperature detecting means failing halfway and the heater being continuously operated unnecessarily. That is the issue.

In order to solve the above problems, a first invention of the present application includes a heating unit and a water passage that communicates a water supply pipe and a hot water pipe through a heat exchanger heated by the heating unit. A water heater in which the water temperature detecting means is arranged at the section, the temperature detecting means is arranged, a heater is arranged in at least a part of the water passage, and the temperature detected by the air temperature detecting means in a state where the operation of the water heater is stopped When the heater is operated until the temperature detected by the air temperature detecting means exceeds the reference temperature or the operation of the water heater is started , the detected temperature of the water temperature detecting means during the heater operation is When the temperature exceeds a predetermined temperature, the operation of the heater is stopped. When the heater is normally operated in a state where the air temperature is equal to or lower than the reference temperature, the water temperature detecting means for the water passage is arranged. The water temperature of the part Characterized in that the normal manner is set to the lower limit and equal to the temperature of the temperature range does not rise.

  According to the first invention, even if the temperature detecting means fails halfway and the heater is operated unnecessarily, if the water temperature in the portion where the water temperature detecting means of the water passage is disposed exceeds the predetermined temperature, Operation is stopped. Therefore, the heater does not continue to operate unnecessarily, and it is possible to prevent energy from being wasted.

  Here, if the heater is operated unnecessarily and then the operation of the water heater is resumed, hot water may be discharged from the tapping pipe. Therefore, in the first invention, it is desirable that the water temperature detecting means is disposed in the water passage on the downstream side of the heat exchanger. According to this, the temperature of the water in the portion of the water passage on the downstream side of the heat exchanger, which is closer to the hot water discharged from the tapping pipe, is detected compared to the water in the portion of the water passage on the upstream side of the heat exchanger. Therefore, even when the heater is operated unnecessarily, it is possible to prevent hot water from being discharged when the operation of the water heater is resumed, which is safe.

Further, the predetermined temperature, when operating the normally heaters as temperature is a reference temperature or less of the above conditions, the temperature of the portion where the water temperature detecting means water passage is disposed does not rise to the steady temperature is set in a range of lower and similar temperature, when operating is normally heater, Ru can ensure that the heater can not be deactivated by mistake. However, when the heater is normally operated, the detected temperature of the water temperature detecting means may temporarily exceed a predetermined temperature, and in this case, the heater operation should not be stopped. Therefore, in the first aspect of the invention, it is desirable to stop the operation of the heater when the temperature detected by the water temperature detecting means continues for a predetermined time.

  Moreover, 2nd invention of this application is equipped with a water passage which connects a water supply pipe and a tapping pipe through a heat exchanger heated by the heating means, and a water temperature detection means is a part of the water passage. A water heater to be disposed, wherein the temperature detecting means is disposed, a heater is disposed in at least a part of the water passage, and the temperature detected by the temperature detecting means is not more than a predetermined reference temperature in a state where the operation of the water heater is stopped. When the heater is activated, the heater is stopped when the degree of increase in the temperature detected by the water temperature detecting means when the heater is activated exceeds a predetermined value.

  According to the second aspect of the present invention, the temperature detection means breaks down halfway, and the heater is operated unnecessarily, so that the degree of increase in the water temperature at the portion where the water temperature detection means in the water passage is disposed is greater than or equal to a predetermined value. Then, the operation of the heater is stopped. Therefore, the heater does not continue to operate unnecessarily, and it is possible to prevent energy from being wasted.

The block diagram of the water heater of embodiment of this invention. The flowchart which shows the control content of 1st Embodiment performed with the water heater of FIG. The flowchart which shows the control content of 2nd Embodiment performed with the water heater of FIG.

  With reference to FIG. 1, reference numeral 1 denotes a water heater, and the water heater 1 includes a combustion housing 2. In the combustion housing 2, there are housed a burner 3 as a lower heating means and a heat exchanger 4 heated by the burner 3. The heat exchanger 4 recovers and heats the main heat exchanger 41 that is heated by recovering the sensible heat of the combustion gas from the burner 3, and the latent heat of the combustion gas that has passed through the main heat exchanger 41. The auxiliary heat exchanger 42 is used.

  The fuel gas supply path to the burner 3 is provided with an electromagnetic valve 31 and a proportional valve 32. Further, the three branch gas supply paths branched downstream of the proportional valve 32 are used for capacity switching. An electromagnetic valve 33 is interposed. A combustion fan 5 for supplying combustion air is connected to the lower end of the combustion housing 2, and an exhaust port 6 is opened at the upper end of the combustion housing 2.

  Further, the water heater 1 includes a water passage 7 that communicates the water supply pipe 71 and the hot water outlet pipe 72 outside the water heater 1 through the heat exchanger 4, and a water temperature detection is provided in a part of the water passage 7. Means are provided. That is, a heat exchange thermistor 73 serving as a water temperature detecting means is disposed in a portion of the water flow path 7 on the downstream side of the heat exchanger 4 and located upstream from a junction of a bypass passage 75 described later. A tapping thermistor 74 serving as a water temperature detecting means is disposed downstream of the junction. A bypass passage 75 that does not pass through the heat exchanger 4 is branched from a portion of the water passage 7 on the upstream side of the heat exchanger 4, and the bypass passage 75 joins a portion of the water passage 7 on the downstream side of the heat exchanger 4. doing.

  The water heater 1 is provided with an air temperature thermistor 8 serving as air temperature detecting means on the bottom surface thereof, and on the upstream side and the downstream side of the branch portion of the bypass passage 75 on the upstream side of the heat exchanger 4. The heater 76 is disposed in the portion of the water passage 7 on the downstream side of the heat exchanger 4 and upstream and downstream of the joining portion of the bypass passage 75 and the bypass passage 75. Then, when the detected temperature of the temperature thermistor 8 becomes a predetermined reference temperature or lower by the controller C in the water heater 1 while the operation of the water heater 1 is stopped, the heater 76 is operated to Freezing is prevented. The duty ratio when the heater 76 is activated is determined according to the temperature detected by the temperature thermistor 8.

  By the way, if the temperature thermistor 8 is disconnected or short-circuited, it can be determined that the resistance value has become very small or large, so that it can be determined that the failure has occurred. Can not. In this case, even when the actual temperature is not lower than the predetermined reference temperature, the temperature detected by the temperature thermistor 8 is lower than the reference temperature, causing the heater 76 to be operated unnecessarily, and the energy is increased. It will be wasted.

  Therefore, in the first embodiment, the controller C stops the operation of the heater 76 when a state where the detected temperature of the water temperature detecting means during the operation of the heater 76 is a predetermined temperature or more continues for a predetermined time. Hereinafter, the operation and the operation stop of the heater 76 according to the first embodiment will be described in detail with reference to FIG.

  First, when the user turns on the water heater 1, has the detected temperature of the temperature thermistor 8 been below a predetermined reference temperature To (for example, 10 ° C.) set for preventing freezing of the water passage 7 in STEP 1? Determine whether or not. When the detected temperature of the temperature thermistor 8 becomes equal to or lower than To, the heater 76 is operated in STEP2.

  When the heater 76 is activated, it is determined in STEP 3 whether or not there is an operation instruction for the water heater 1. If there is no operation instruction for the water heater 1, in STEP 4, temperature detection is started by the hot water thermistor 74 disposed in the water passage 7 on the downstream side of the heat exchanger 4, and the operation of the water heater 1 is started again in STEP 5. It is determined whether or not there is an instruction, and if there is no operation instruction, in STEP 6, it is determined whether or not the detected temperature of the tapping thermistor 74 is equal to or higher than a predetermined temperature α and the state has continued for a predetermined time (for example, 30 seconds). . If the state where the detected temperature of the hot water thermistor 74 is equal to or higher than α continues for a predetermined time, it is determined that the temperature thermistor 8 has failed, and in STEP 7, the operation of the heater 76 is stopped and an error is displayed. According to this, even if the temperature thermistor 8 breaks down halfway and the heater 76 is operated unnecessarily, if the water temperature at the portion where the hot water thermistor 74 of the water passage 7 is arranged becomes α or more, the heater 76 Operation is stopped. Therefore, the heater 76 does not continue to operate unnecessarily, and it is possible to prevent energy from being wasted.

  When the heater 76 is normally operated in a state where the temperature is equal to or lower than the reference temperature To, the predetermined temperature α does not steadily increase the water temperature of the portion where the hot water thermistor 74 of the water passage 7 is disposed. It is desirable to set the temperature to be equal to the lower limit of the temperature range (for example, 30 ° C.) so that the heater 76 is not erroneously stopped when the heater 76 is operating normally. However, when the heater 76 is normally operated, the detected temperature of the hot water thermistor 74 may temporarily become α or higher. In this case, the operation of the heater 76 should not be stopped. Therefore, in the first embodiment, as described above, when the state where the temperature detected by the hot water thermistor 74 is equal to or higher than α continues for a predetermined time, the operation of the heater 76 is stopped.

  On the other hand, if it is determined in STEP 6 that the detected temperature of the hot water thermistor 74 is not higher than α for a predetermined time, the operation instruction of the water heater 1 is issued when the detected temperature of the temperature thermistor 8 becomes higher than To in STEP 8. It is determined whether or not there is an instruction to stop the operation of the heater 76 that is issued when it is issued. If there is no instruction to stop the operation of the heater 76, the process returns to STEP5. If there is an instruction to stop the operation of the heater 76, the operation of the heater 76 is stopped and the process returns to STEP1.

  If it is determined in STEP 3 or STEP 5 that there is an operation instruction for the water heater 1, the operation of the heater 76 is stopped in STEP 10, and it is determined in STEP 11 whether or not the operation of the water heater 1 is stopped. When the operation of the water heater 1 is stopped, it is determined in STEP 12 whether or not the detected temperature of the hot water thermistor 74 is lower than a predetermined temperature β, and when the detected temperature of the hot water thermistor 74 becomes lower than β, the process returns to STEP 1. Β is set to 10 ° C., for example, in accordance with the lower limit of the temperature range where there is no fear of freezing.

  Here, when the heater 76 is operated unnecessarily and then the operation of the water heater 1 is resumed, hot water may be discharged from the hot water discharge pipe 72. In the first embodiment, the hot water thermistor 74 causes the downstream side of the heat exchanger 4 that is closer to the hot water discharged from the hot water pipe 72 than the water in the portion of the water passage 7 upstream of the heat exchanger 4. Therefore, even if the heater 76 is unnecessarily activated, hot water can be prevented from being discharged when the operation of the water heater 1 is resumed. It is.

  In the first embodiment, instead of detecting the temperature by the hot water thermistor 74, the heat exchanger thermistor 73 disposed in the portion of the water flow path 7 on the downstream side of the heat exchanger 4 in the same manner as the hot water thermistor 74. It is also possible to detect the temperature. In this case, α may be set to 70 ° C., for example.

  Next, a second embodiment will be described. In the second embodiment, the controller C stops the operation of the heater 76 when the degree of increase in the detected temperature of the water temperature detection means during the operation of the heater 76 becomes a predetermined value or more. Hereinafter, with reference to FIG. 3, the operation | movement and operation stop of the heater 76 of 2nd Embodiment are explained in full detail.

  First, when the user turns on the water heater 1, in STEP 101, it is determined whether or not the detected temperature of the temperature thermistor 8 is equal to or lower than To, and when the detected temperature of the temperature thermistor 8 becomes equal to or lower than STEP 102, STEP 102. Then, the heater 76 is operated.

  When the heater 76 is activated, it is determined in STEP 103 whether or not there is an operation instruction for the water heater 1, and if there is no operation instruction for the water heater 1, the process proceeds to STEP 104, and the temperature detected by the hot water thermistor 74 at that time is determined. Store as T1. Subsequently, in STEP 105, it is determined again whether or not there is an operation instruction for the water heater 1, and if there is no operation instruction for the water heater 1, a predetermined time (for example, 30 minutes) is maintained in STEP 106 with the heater 76 operating. ) Determine whether or not it has passed. When a predetermined time has passed in this state, the process proceeds to STEP 107, and the temperature detected by the hot water thermistor 74 at that time is stored as T2. Then, in STEP 108, as the degree of increase in the detected temperature of the hot water thermistor 74, the amount of increase in the detected temperature of the hot water thermistor 74 in a predetermined time, that is, T2-T1 is obtained. It is determined whether or not. If T2−T1 ≧ Y, the operation of the heater 76 is stopped and an error is displayed in STEP109. According to this, when the temperature thermistor 8 fails halfway and the heater 76 is operated unnecessarily, the operation of the heater 76 is stopped when T2−T1 ≧ Y. Therefore, the heater 76 does not continue to operate unnecessarily, and it is possible to prevent energy from being wasted.

  On the other hand, if it is determined in STEP108 that T2-T1 <Y, in STEP110, the operation of the heater 76 that is issued when the detected temperature of the temperature thermistor 8 becomes higher than To or when the operation instruction for the water heater 1 is issued is stopped. It is determined whether or not there is an instruction. When there is an operation stop instruction, the operation of the heater 76 is stopped in STEP 111 and the process returns to STEP 101.

  If it is determined in STEP 103 or STEP 105 that there is an operation instruction for the water heater 1, the operation of the heater 76 is stopped in STEP 112, and it is determined whether or not the operation of the water heater 1 is stopped in STEP 113. When the operation of the container 1 is stopped, in STEP 114, it is determined whether or not the detected temperature of the hot water thermistor 74 is lower than the predetermined temperature β, and when the detected temperature of the hot water thermistor 74 becomes lower than β, the process returns to STEP 1.

  In the second embodiment, the degree of increase in the detected temperature of the hot water thermistor 74 is defined as the amount of increase in the detected temperature during a predetermined time when the heater 76 is operating. It is also possible to set the amount of increase in the detected temperature from the start of energization to the stop of energization. In this case, since the water temperature in the water passage 7 greatly increases between the time when the heater 76 is energized for the first time and the time when the energization is stopped, the rising amount of the tapping thermistor 74 after the first time when the heater 76 is energized and before the energization is stopped. It is desirable to stop the operation of the heater 76 when becomes equal to or greater than a predetermined value.

  Further, in the second embodiment, instead of detecting the temperature by the tapping thermistor 74, it is also possible to detect the temperature by the heat exchanger thermistor 73. In this case, Y may be set to 25 ° C., for example.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, although the temperature thermistor 8 is disposed on the bottom surface of the water heater 1 in the above embodiment, it may be disposed on the top surface or the side surface. Moreover, what is arrange | positioned in the part different from the said embodiment as a water temperature detection means may be used, and a heater may be arrange | positioned in the part where the water flow path 7 different from the said embodiment is easy to freeze. . Further, in the above embodiment, the bypass passage is provided, but the bypass passage may not be provided.

DESCRIPTION OF SYMBOLS 1 ... Hot water heater, 3 ... Burner (heating means) 41, 42 ... Heat exchanger, 7 ... Water passage, 71 ... Water supply pipe, 72 ... Hot water pipe, 73 ... Heat exchange thermistor (water temperature detection means), 74 ... Hot water Thermistor (water temperature detection means), 76 ... heater, 8 ... temperature thermistor (temperature detection means).

Claims (4)

A water heater comprising a heating means and a water passage that communicates the water supply pipe and the hot water outlet pipe through a heat exchanger heated by the heating means, and a water temperature detection means is disposed in a part of the water passage,
When the temperature detecting means is arranged and a heater is arranged at least in part of the water passage, when the temperature detected by the air temperature detecting means becomes a predetermined reference temperature or less with the operation of the water heater stopped, the temperature detecting means The heater is operated until the detected temperature exceeds the reference temperature or the operation of the water heater starts .
When the detection temperature of the water temperature detection means during the heater operation becomes equal to or higher than a predetermined temperature, the operation of the heater is stopped .
This predetermined temperature is equivalent to the lower limit of the temperature range in which the water temperature of the portion where the water temperature detecting means of the water passage is arranged does not rise steadily when the heater is normally operated in a state where the air temperature is below the reference temperature. The water heater is characterized by being set to a temperature of .   The hot water heater according to claim 1, wherein the water temperature detecting means is disposed in a water passage on the downstream side of the heat exchanger.   3. The water heater according to claim 1, wherein the operation of the heater is stopped when a state where the temperature detected by the water temperature detecting means is equal to or higher than the predetermined temperature continues for a predetermined time. A water heater comprising a heating means and a water passage that communicates the water supply pipe and the hot water outlet pipe through a heat exchanger heated by the heating means, and a water temperature detection means is disposed in a part of the water passage,
In addition to the air temperature detection means, a heater is placed in at least part of the water passage, and the heater operates when the temperature detected by the air temperature detection means falls below a predetermined reference temperature with the hot water heater stopped operating In what
A water heater, wherein the heater operation is stopped when the degree of increase in the temperature detected by the water temperature detection means when the heater is activated exceeds a predetermined value.

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