JP2017078518A - Hot water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water supply system capable of supplying hot water with good responsiveness without delay in hot water supply operation even if a request amount of hot water supply used by a user changes, while taking a workaround against the occurrence of system down caused by failure of a flow rate sensor or the like.SOLUTION: When two main water heaters are set on standby for hot water supply, and the flow rate of entering water is detected, if the flow rate of the entering water is relatively low, in principle, one unit is switched to the water impossible state, and hot water supply operation is performed by only one main water heater. On the other hand, under the condition that the flow rate of the entering water, in which the flow rate of the entering water is detected, is larger than the predetermined continuation availability determination flow rate (YES in S6), one unit is changed to a sub water heater but the water permeable state is maintained. Thereby, hot-water supply operation with two units is performed (S8).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a hot water supply system that controls the number of two or more hot water heaters interposed in parallel between a water inlet path and a hot water outlet path, and in particular, a system down caused by a failure of a water amount sensor or the like at the start of hot water supply. The present invention relates to a technology that can supply hot water in response to a change in a required amount when a user uses hot water, while taking measures that can surely avoid the occurrence of hot water.

In the following Patent Document 1, in a hot water supply system that controls the number of operating hot water heaters, the number of hot water heaters to be operated for hot water supply is increased when the amount of hot water discharged from the water heater during hot water supply operation reaches a predetermined flow rate. Is described.
Similarly, in Patent Document 2, in a hot water supply system that similarly controls the number of operating water heaters, each water heater is provided with an open / close valve that opens and closes incoming water, and is opened and closed in advance when waiting for hot water supply operation. The number of hot water heaters (main water heaters) that will be able to pass water if the downstream hot water tap etc. are opened by the first and to be fired first is set instead of one. Is described.

Japanese Patent No. 2586780 Patent No. 5527607

  By the way, there are two main water heaters during hot water supply standby, and when a hot water supply request is made, the reason why the two water heaters are operated for combustion first is a system down (hot water supply) caused by the occurrence of a flow sensor failure. There is a reason for surely avoiding the occurrence of a system stoppage in which no unit is burned even if a request occurs. That is, in order to use the flow rate sensor as a trigger for combustion operation start control, the flow rate sensor plays a role of detecting the occurrence of water flow accompanying the opening operation of the hot water tap by the user, and is provided in each water heater. In the case of a water heater (sub-water heater) that starts water supply operation by switching to allow water flow based on a command from the system controller, the flow rate sensor can be used even if the command is sent from the system controller to switch to allow water flow. If there is no output of flow rate detection information from, it can be detected that an abnormality has occurred in the flow rate sensor. However, in the case of the main water heater, since it has been switched to allow water to flow in advance, even if there is no output of flow rate detection information, there is no opening operation of the hot water tap by the user, and an abnormal flow sensor has occurred. Therefore, even if the user opens the hot-water tap, the combustion is not started and the hot-water supply is disabled (system down). As a measure for avoiding such a situation, it is effective to set two water heaters as the main water heaters during the hot water supply standby.

  Thus, for example, one of the two water heaters outputs detection information of a certain flow rate or more, but the other does not have flow detection information or has an extremely low flow detection. When only information is output, it can be determined that an abnormality has occurred in the flow sensor of the other main water heater or that the possibility is high. On the other hand, if the same flow rate detection information is output from the two main water heaters, it can be confirmed that both of the two main water heaters are normal. It is conceived to change the setting as a sub-water heater by continuing as a water heater and switching the other water heater to a non-water-permeable state. As a result, the incoming water flow divided into the two water heaters can be concentrated on one main water heater, and the hot water supply operation can be stably performed even when the amount of hot water used at the start of hot water supply is relatively small. Is considered.

  However, even when the amount of hot water used at the start of hot water supply by the user is a small flow rate, there are cases in which it is desired to gradually increase the flow rate or to increase it suddenly. At the start, after passing water once through the two main water heaters, if one of the main water heaters is switched to be incapable of water supply and the other main water heater is used to supply hot water, the hot water supply operation will be delayed, There is a possibility that the responsiveness to the change in the amount of hot water use by the user is deteriorated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to request use of hot water by a user while taking a workaround for the occurrence of a system down due to a failure of a flow sensor or the like. An object of the present invention is to provide a hot water supply system that can supply hot water with good responsiveness without causing a delay in hot water supply operation even when the amount changes.

  To achieve the above object, a plurality of water heaters installed in parallel between a water inlet path and a hot water outlet path, and the plurality of water heaters connected in communication with the plurality of water heaters A hot water supply system configured to increase or decrease the number of hot water heaters to be operated in hot water supply according to a required hot water supply amount. The following technical measures were taken.

  That is, a plurality of main water heaters that are maintained in a state where water can be passed during standby for hot water supply operation, and the water flow rate detected by one of the plurality of main water heaters is the first water flow condition. When the above conditions are satisfied, the principle control unit that switches and controls the other main water heaters to be incapable of passing water, and the total flow rate detected by each of the plurality of main water heaters is the second water flow rate. An exception control unit that maintains all of the plurality of main water heaters in a state in which water can be passed without performing switching control to a state in which water cannot pass, provided that the conditions are satisfied. (Claim 1).

  In the case of the present invention, a failure of a flow sensor for detecting the flow rate of water flow by providing a plurality of main hot water heaters maintained in a state that allows water flow during standby for hot water supply operation, and by providing principle control by the principle control unit It is possible to reliably avoid the occurrence of system down due to the above, and to stably operate the hot water supply particularly when the required amount of hot water supply is relatively small. In addition, when the second water passage condition is established, all of the main water heaters can be passed through without switching control to a state in which the water flow is impossible by the principle control unit. Since the control is performed by the exception control unit that is maintained at the same time, especially when the required amount of hot water supply is relatively large or when it is initially increased at least, the user does not delay the hot water supply operation. Therefore, it is possible to quickly respond to an increase in the amount of hot water supply required due to the responsiveness.

  In the hot water supply system of the present invention, as the second water flow condition, a new water heater is newly provided from a state in which the total flow rate is in a state where water can pass through only one main water heater. It can be set to be equal to or higher than the determination flow rate for increasing the number of hot water supply operation by switching to a water flowable state (Claim 2). By doing in this way, even if it does not temporarily switch to other water heaters in a state where water cannot be passed, leaving one of the plurality of main water heaters in place, the plurality of main water heaters can be passed as they are. The exceptional control of maintaining functions effectively, so that it is possible to stably supply hot water by a hot water supply operation by a plurality of main water heaters, and it is possible to immediately cope with future increases in hot water demand. It becomes like this.

  In the hot water supply system of the present invention, the first water flow condition is a state in which the water flow rate is higher than a second predetermined flow rate that can be detected, although the water flow rate is smaller than the first predetermined flow rate that is a hot water start operation condition in the water heater Can be continued for the first determination time, or a state where the flow rate is higher than the first predetermined flow rate can be continued for the second determination time (Claim 3). By doing in this way, this invention can be actualized more and the effect | action of this invention can be clarified more.

  In the hot water supply system in that case, the second determination time is a determination time for determining whether or not the second water flow condition is satisfied, and the second water flow condition is determined before the second determination time elapses. If satisfied, the control by the control unit can be canceled and the control by the exception control unit can be executed (claim 4). By doing in this way, while it can fully determine whether the 2nd water flow condition is satisfied, the determination of the 1st water flow condition can also be made reliable.

  In the case of the present invention, since there are a plurality of main water heaters maintained in a state in which water can be passed during standby for hot water supply operation, the principle control by the principle control unit is provided, so the flow rate for detecting the water flow rate It is possible to reliably avoid the occurrence of a system down due to a sensor failure or the like, and it is possible to stably operate the hot water supply particularly when the required amount of hot water supply is relatively small. In addition, when the second water passage condition is established, all of the main water heaters can be passed through without switching control to a state in which the water flow is impossible by the principle control unit. Since the control is performed by the exception control unit that is maintained at the same time, especially when the required amount of hot water supply is relatively large or when it is initially increased at least, the user does not delay the hot water supply operation. Therefore, it is possible to quickly respond to an increase in the amount of hot water required due to the responsiveness with good responsiveness.

  In particular, according to the hot water supply system of the second aspect, as the second water supply condition, a water heater in which the total flow rate of the water flow detected by the plurality of main water heaters is in a state that allows water to flow is the main. By switching from a state where there is only one water heater to a state in which one water heater can be passed through and allowing the number of water heaters to operate, the flow rate is equal to or greater than the judgment flow rate. Effectively performs exception control to maintain multiple main water heaters in a state that allows passage of water, without leaving one of the main water heaters and temporarily switching to other water heaters. Accordingly, it is possible to stably supply hot water by a hot water supply operation using a plurality of main hot water heaters, and it is possible to immediately cope with a future increase in required amount of hot water supply.

  According to the hot water supply system of the third aspect, the first water flow condition is less than the first predetermined flow rate that is a condition for starting the hot water supply operation in the water heater, but is less than the second predetermined flow rate at which the water flow rate can be detected. The present invention can be further embodied by either the state in which the large amount continues for the first determination time or the state in which the amount exceeds the first predetermined flow rate continues for the second determination time. The effect of can be obtained more clearly.

  According to the hot water supply system of the fourth aspect, the second determination time is set as a determination time for determining whether or not the second water flow condition is satisfied, and the second water flow until the second determination time elapses. If the condition is satisfied, it is possible to sufficiently determine whether or not the second water flow condition is satisfied by adopting a configuration in which the control by the exception control unit is canceled and the control by the exception control unit is executed in principle. On the other hand, the determination of the first water flow condition can also be ensured.

It is the whole schematic diagram which shows the example of the hot water supply system provided with the control apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the structural example of each water heater of FIG. It is a block block diagram which shows the structure which concerns on the operation control of the hot water supply system of FIG. It is a flowchart which shows the typical process of number control. It is a flowchart which shows the first half part of the hot water supply start time control of FIG. It is a flowchart which shows the second half part of the hot water supply start time control of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a hot water supply system according to an embodiment of the present invention. In this hot water supply system, two or more predetermined numbers of the same number of hot water heaters 3, 3,... Controlled by the system controller 2 are connected in parallel between the incoming water path 5 and the outgoing hot water path 6. In the illustrated example, a case where the hot water supply system is configured by six water heaters 3, 3,... Is illustrated, and the reference numerals 3a, 3b,.

  Each water heater 3 is connected to a water inlet passage 5 whose water inlet 32 receives water supplied from a water pipe or the like, while a hot water outlet 33 has a hot water outlet or a hot water tap or the like as a downstream end. Are connected in parallel. In the hot water supply system, each hot water heater 3 is controlled by hot water supply operation mainly based on the operation control of the combustion system by an individual controller 31 built in each hot water heater 3, and each individual controller 31 communicates with the system controller 2 and a communication connection line 71. Thus, the system controller 2 is connected so as to be capable of two-way communication individually, and receives information on the role assigned mainly in the unit control and information on the set hot water temperature set in the remote controller 20.

  The system controller 2 is connected to the individual controllers 31, 31,... Of each water heater 3 through the communication connection line 71, so that the system controller 2 is connected to the number of water heaters 3, 3,. (6 units in the example) and the respective water heaters 3a, 3b,... Are recognized and stored in, for example, a nonvolatile memory (see the storage unit 211 in FIG. 3). Further, the system controller 2 and the individual controllers 31, 31,... Each have an MPU, a memory (EEPROM), an interface, etc., each of which stores various control programs, each having a power supply board, and each water heater 3 A power supply current from a power supply line 72 for supplying power to the power supply is received via the power supply board.

  An example of each water heater 3 constituting the hot water supply system will be described. FIG. 2 shows a gas water heater that burns gas as fuel as an example of the water heater 3. In addition, the water heater 3 illustrated in FIG. 2 heats the incoming water from the water inlet 32 by combustion heat, and discharges the heated hot water from the outlet 33, and has such a function. If so, the hot water supply system 2 of the present invention can be configured using another type of water heater that does not use the heat exchanger 34 described later, or an oil water heater that burns petroleum (for example, kerosene) as fuel. .

  The water heater 3 includes a heat exchanger 34, a water inlet 35 for allowing water from the water inlet path 5 to enter the heat exchanger 34 through the water inlet 32, and hot water heated by the heat exchanger 34. A hot water outlet 36 for discharging hot water from the gate 33 to the hot water outlet 6, a bypass 37 for mixing water with the hot water discharged from the heat exchanger 34, and the heat exchanger 34 are heated by combustion heat. And a combustion burner 38 as a combustion section. The heat exchanger 34 and the combustion burner 38 are built in a can body 39, and a blower fan 40 is attached to the can body 39. And the combustion burner 38 is combusted in response to the combustion air supplied from the blower fan 40, and the water in the heat exchanger 34 is heat exchange heated.

  An inlet flow rate sensor for detecting the incoming water flow rate (can flow rate passed through the heat exchanger 34) in the water intake channel 35 at a position closer to the heat exchanger 34 than the branch point to the upstream end of the bypass channel 37. 41 is provided, and an incoming water temperature sensor 42 that detects the incoming water temperature upstream of the branch point is provided. The hot water supply passage 36 is provided with a can body temperature sensor 43 for detecting the temperature of the can body immediately after being heated by the heat exchanger 34 at a position upstream of the joining position with the downstream end of the bypass passage 37. A flow rate control valve 44 that adjusts the hot water flow rate at a position downstream of the merging position and a hot water temperature sensor 45 that detects the temperature of the hot water that is actually supplied to the hot water supply are provided. Further, the bypass passage 37 is provided with a bypass flow rate control valve 46 for mixing the water from the incoming water passage 35 at a predetermined mixing ratio with respect to the hot water of the hot water outlet passage 36, and this mixed water supplies hot water. The temperature of the hot water is adjusted to a predetermined set temperature. Of the flow rate control valve 44 and the bypass flow rate control valve 46, at least the flow rate control valve 44 has a fully closed switching function that can be closed to a fully closed state in which the valve opening amount is zero based on a control signal from the system controller 2. In the fully closed switching state, the incoming water from the incoming water path 5 is blocked and the water cannot pass. As a result, the use of hot water supply / nonuse (water flow is possible / impossible of water flow) by controlling the number of units or the like is performed by setting the flow rate control valve 44 to the normal flow rate adjustment function or by the fully closed switching function. Depending on whether the switching state is set, it is not necessary to separately attach a dedicated electromagnetic on-off valve to an external route or the like.

  As the hot water supply operation control by the individual controller 31 provided in each water heater 3, the incoming water flow rate from the incoming water route 5 to the incoming water channel 35 is greater than the minimum operating flow rate (MOQ) due to the hot water supply request (for example, opening of the hot water tap). Is detected by the incoming water flow rate sensor 41, the fuel gas supply system (not shown) to the combustion burner 38, the combustion system 47 including the ignition mechanism (shown only in FIG. 3), the blower fan 40, etc. By controlling the operation, the combustion burner 38 is burned at a predetermined combustion amount so that the temperature of the hot water discharged into the hot water discharge path 6 after the mixed water becomes the set hot water temperature. That is, control values for the corresponding fuel gas supply amount and air supply amount are determined based on the predetermined air-fuel ratio and the required combustion amount (request number), and the calculated fuel gas supply amount is calculated. The fuel gas supply system is controlled to operate as described above, while the blower fan 40 is controlled to achieve the determined air supply amount.

  Each individual controller 31 receives a control signal for permitting passage of water (using hot water supply) or shutting off water flow (not using hot water supply) from the number control unit 21 through communication with the system controller 2 and performs corresponding control. It is supposed to run. That is, when a water flow cut-off command is received, a fully closed switching command is issued to switch the flow control valve 44 to a fully closed state, so that even if water flows into the water intake path 5, the water does not enter the water intake path 35. On the other hand, when a water passage permission command is received, an open switching command is issued to open the flow control valve 44 so that water can enter the water passage 35 from the water passage 5 to the water passage 35. It has become.

  The system controller 2 includes a number control unit 21 as shown in FIG. The number control unit 21 includes a storage unit 211 and is configured to execute typical control shown in FIG. Such a system controller 2 can be installed separately from each water heater 3, or can be installed in any one of the water heaters 3 together with the individual controller 31. The number control by the number control unit 21 is basically to increase / decrease the number of hot water heaters 3, 3,... That are operated in hot water supply according to the required amount (hot water request amount) related to the use of hot water from the hot water supply destination. Mainly, the hot water supply start control (step SB1), the hot water supply control for increasing / decreasing the number of hot water heaters operated according to the required hot water supply amount (step SB2), and finally all the hot water heaters 3, 3 is provided with a hot water supply end control (step SB3) for stopping the hot water supply operation of 3,.

  That is, the system controller 2 selects any two water heaters (for example, 3a and 3b) out of all the water heaters 3a, 3b,... Constituting the hot water system, and selects the two water heaters 3a, 3b. The main water heaters are assigned with roles assigned to the sub-water heaters that sequentially operate the hot water supply operation while satisfying other hot water heaters 3c, 3d,..., And the setting information is stored in the storage unit 211. Allocation setting of main water heaters can be performed in advance by main water heater setting control based on separate hot water supply operation history, etc., switched at the elapse of a predetermined time or according to the accumulated combustion time for each water heater Can be switched. Along with this switching, one of the other hot water heaters 3c, 3d,... That has been assigned as the sub-water heater until then is newly assigned as the main water heater and stored in the storage unit 211. .

  And during the hot water supply standby, only the main hot water heaters 3a, 3b are maintained in a state where water can be passed, and the other sub water heaters 3c, 3d,. That is, during the hot water supply standby, the incoming water path 5 and the outgoing hot water path 6 are brought into a communication state (a state in which water can pass through) only through the main hot water heaters 3a and 3b, and the other sub hot water heaters 3c, 3d,. The path 6 is kept in a cut-off state (water-impossible state). In the present embodiment, the mutual switching between the water flowable state and the water non-flowable state is realized by switching the flow rate control valve 44 between the open state and the fully closed state, but the present invention is not limited to this. In addition, an on-off valve or the like can be separately provided between the water inlet path 5 or the hot water path 6 and each water heater 3.

  Here, the main water heater is a water heater that is maintained in a state where water can be passed during standby for hot water supply, and the sub water heater is a water heater that is maintained in a state where water cannot be passed during standby for hot water. If the water flow is possible, water is introduced when the user starts using the hot water supply such as opening the hot water tap, and when the incoming water flow rate sensor 41 detects an incoming water flow rate exceeding the minimum operating flow rate (MOQ), Operation control is started (combustion start). On the contrary, if it is in a state where water cannot be passed, even if the use of the hot water is started, water is not entered, so that the hot water supply operation (combustion operation) is not performed.

As described later, the hot water supply start control (step SB1) includes principle control by the principle control unit and exception control by the exception control unit. The principle control is mainly for avoiding a system down due to a failure of the incoming water flow sensor, etc., while the exception control avoids the occurrence of the system down, but mainly responds to an increase in the required amount of hot water supply. This is for hot water supply operation with good quality. Hereinafter, the hot water supply start control will be described with reference to FIGS. 5 and 6. The detected incoming water flow rate by the incoming water flow rate sensors 41 and 41 sent from the main hot water heaters 3a and 3b in the state of waiting for hot water supply is monitored (step S1). And the condition of the incoming water flow rate (water flow rate) Q1 of the first main water heater 3a is the first water flow condition A (continue for the first determination time t1 in a state where the following conditional expression (1) is satisfied). Is satisfied (YES in step S2), the main water heater is changed to the first main water heater 3a only, the second main water heater 3b is changed to a sub water heater, and the water passage is disabled (step S3).
MOQ ON flow rate> Q1 ≧ MIN flow rate (1)
Here, the ON flow rate of the MOQ is an incoming water flow rate (water flow rate) that serves as a trigger for starting hot water supply operation control when a hot water tap or the like is opened to enter the hot water heater 3 from the incoming water path 5. For example, 1.7 L / min is set. On the other hand, the OFF flow rate of the MOQ, which will be described later, means that the hot water tap or the like is operated to the closed side during the hot water supply operation, the incoming water flow rate decreases, and finally the hot water supply operation control is finished. This is a water flow rate (water flow rate) that is a trigger for the flow rate, for example, 1.3 L / min. The MIN flow rate (minimum judgment flow rate) is, for example, 1 L / min. Further, a relatively short time (for example, 1 second) is set as the first determination time t1, and thereby, the first water flow condition (1) in the relatively low flow rate range before the MOQ is turned on is established. For example, it is possible to increase the rate of increase of the incoming water flow rate by changing the number of water heaters in a state where water can be passed quickly to one.

  Since the two main water heaters 3a and 3b are in a water-permeable state, the water entering from the water inlet path 5 is diverted into the main water heaters 3a and 3b by opening the hot water tap or the like. . Therefore, even if the incoming water flow rate to the first main water heater 3a, which is one of them, is lower than the ON flow rate of the MOQ, but higher than a predetermined minimum judgment flow rate, the incoming water flow rate sensor 41 of the first main hot water heater 3a. Is determined to be normal, the setting of the second main water heater 3b is immediately changed to a sub-water heater, and the sub-water heater 3b is switched to a non-water-permeable state so that only the first main water heater 3a passes. Maintain water availability. By using only one main water heater 3a for performing the hot water supply operation, even if the required amount of hot water supply is low, the hot water can be stably supplied. In addition, about the incoming water flow rate sensor 41 of the water heater 3b, by changing the setting to the sub water heater, if it has fallen into an error state such as a failure, it is switched from the water non-permeable state to the water permissible state thereafter. When no hot water supply operation is performed, an error state can be detected because there is no output of flow rate detection information.

  Thereafter, the process proceeds to hot water supply control (step SB2, see FIG. 4), and if the amount of hot water supply increases, the passage of water is permitted to any one of the sub water heaters 3b, 3c,. A command will be sent. Thereby, the flow control valve 44 of the sub water heater 3b is opened and switched, and the sub water heater 3b is burned together with the main water heater 3a when the incoming water flow rate sensor 41 detects the incoming water flow rate equal to or higher than the MOQ to perform the hot water supply operation. If the two hot water heaters 3a and 3b are combusted and the required amount of hot water supply is insufficient, the number of combustion units is increased so that another sub water heater 3 (for example, 3c) is also combusted. Similarly, when the required amount of hot water supply is reduced, the number of combustion units is sequentially reduced by sequentially sending the combustion prohibition commands accordingly.

On the other hand, if the first water flow condition (1) is not satisfied in step S2 (NO in step S2), the state of the incoming water flow rate Q1 of the first main water heater 3a is the first water flow condition B. (Continuing for the second determination time t2 to be described later while satisfying the next conditional expression (2)), that is, whether or not there is an incoming water flow rate equal to or higher than the ON flow rate of the MOQ. First determine.
Q1 ≧ MOQ ON flow rate (2)
If there is no incoming water flow rate equal to or higher than the MOQ ON flow rate (NO in step S4), the process returns to step S1. On the other hand, if there is an incoming water flow rate equal to or higher than the MOQ ON flow rate (YES in step S4), first, a timer for counting a predetermined second determination time t2 is started (step S5), and the first main water heater 3a and It is determined whether or not the total flow rate Q1 + Q2 with both of the second main water heaters 3b is greater than a predetermined continuity determination flow rate, that is, whether or not the next second water flow condition (3) is satisfied ( Step S6).
Q1 + Q2 ≧ continuation determination flow rate (3)
Here, it is determined that the flow rate for determining whether or not continuation is possible may be set such that two water heaters 3a and 3b can continue to be in a state where water can be passed as they are without allowing the water to pass through and the two water heaters can be operated. It is a judgment flow rate for being able to do.

As the continuation possibility determination flow rate Qh, for example, a flow rate represented by the following formula (4) can be adopted.
Qh = (Set flow rate of the first main water heater × 0.5) +5 L / min (4)
Here, the set flow rate in the equation (4) means that the incoming water at the current incoming temperature is heated at the maximum combustion number (maximum combustion capacity), adjusted to a predetermined hot water supply temperature with mixed water, and discharged. It means the maximum can body flow rate that can be obtained, and is a flow rate value set by calculation according to the incoming water temperature detected at that time. As such a continuity determination flow rate Qh, for example, a hot water supply operation is performed by switching from a state in which only one main water heater is in a state where water can be passed to a state in which one water heater can be passed through. It is possible to adopt a flow rate value equal to or greater than the determination flow rate for increasing the number of units to be performed. That is, if the current total incoming water flow rate is equal to or higher than the flow rate at which the number of hot water supply operation is newly increased by one, one of the two hot water heaters 3a and 3b is not allowed to pass water. Even if it is not switched once, it is possible to supply hot water stably with the hot water supply operation with two units, and to keep the two units in a state where water can be passed so that future increases in hot water demand can be dealt with immediately. The hot water supply operation is performed with two units. It should be noted that “0.5” (50% of the set flow rate) in the equation (4) can be changed to “0.3” (30%) when the water supply is set to a low water pressure, or “5 L” of the additional flow rate considering hysteresis. / Min "can be changed and set to" 3L / min ". The change setting can be performed using the remote controller 20 or the like, for example.

  Even if the second water flow condition (3) is not satisfied (NO in step S6), the second water flow condition (3) is satisfied until the second determination time t2 elapses (NO in step S7). If the second water flow condition (3) is satisfied even instantaneously during the second determination time t2 (YES in step S6), both units are in a water flowable state. Maintain (step S8). That is, while maintaining the 1st main water heater 3a as it is in a water flowable state, the 2nd main water heater 3b is also changed into a sub water heater, but is maintained in the water flowable state (step S8). Thus, hot water corresponding to the required hot water supply amount is supplied by two hot water supply operations. If the second water flow condition (3) is satisfied during the second determination time t2, the process of maintaining both water flowable states constitutes exception control by the exception control unit. Thereafter, the process proceeds to hot water supply control (step SB2, see FIG. 4), and control is performed to increase or decrease the number of hot water supply operations to three or four according to the required hot water supply amount. Even if the second determination time t2 elapses, the conditional expression (2) is satisfied, but the second water flow condition (3) is not satisfied (YES in step S7). The process of step S3 is executed as a rule. In other words, the “first water flow condition” is configured by either the first water flow condition A or B, and 2 if either of the first water flow conditions A or B is satisfied. The process of switching one of the main water heaters to a water-impossible state constitutes the principle control by the principle control unit. As described above, although the second determination time t2 is set longer than the first determination time t1, the speed of the transition to step S3 when the first water flow condition (2) is satisfied (YES in step S7). In consideration of the above, a necessary minimum time value (for example, 3 seconds) is set as a time value for confirming the establishment of the second water flow condition. In addition, as a precondition for establishment of the 2nd water flow condition (3) for maintaining both in a water flowable state, both the flow volume Q1 of the 1st main water heater 3a and the flow volume Q2 of the 2nd main water heater 3b are used. It is required that both satisfy an MOQ OFF flow rate (for example, 1.3 L / min) or more. This is because if it is less than the MOQ OFF flow rate, the hot water supply operation of each water heater will be stopped in the first place.

  And even if it performs any process of step S3 or step S8, after hot water supply control (step SB2) and hot water supply end time control (step SB3), hot water supply operation is complete | finished and it transfers to a hot water supply standby state. . During this hot water supply standby, select and assign the two main water heaters again, maintain the two main water heaters in a water-ready state, and wait until the next hot water supply request occurs. become.

  In the case of the above embodiment, two main water heaters are set at the time of standby for hot water supply, one water supply is disabled by detecting the incoming water flow rate, hot water supply operation is performed only by one main water heater, and the required amount of hot water supply Compared to the case where the basic control of switching hot water supply operation with two units by switching to a state in which one sub-water heater can be passed through due to the increase in hot water supply operation, especially when the demand for hot water supply increases by the user, Thus, it is possible to avoid a delay in the rate of increase of the incoming water flow rate with respect to the hot water heater to be used, and it is possible to realize a smooth hot water supply with responsiveness to an increase in the amount of hot water required by the user. That is, when the principle control is uniformly applied, the procedure is such that the flow control valve is closed once in a state where water cannot be passed and then opened again in a state where water can be passed and two hot water supply operations are performed. In addition to the operation time required for the closed conversion and open conversion of 44, the flow rate of water flow into one water heater is divided into two, so the rate of increase in the flow rate of water flow in each water heater is increased. This will result in a delay. In addition, if a relatively large amount of hot water supply is requested from the beginning of the detection of the incoming water flow rate, the combustion operation of the two main water heaters will be started. After waiting for the time required for the determination (for example, 20 seconds), switching to a water flowable state is started, and an operation delay is caused in order to cope with a user's hot water supply request from the viewpoint of response time. Result. On the other hand, in the present embodiment, two main water heaters are set at the time of hot water supply standby, and when one of the water flows is detected, one of the water heaters is larger than a predetermined continuity determination flow. Although the setting is changed to the sub-water heater, the exception control of maintaining the water flowable state and performing the hot water supply operation with two units is performed, so that the user does not delay the hot water supply operation. This makes it possible to quickly respond to changes in the required amount of hot water supply due to the responsiveness. In addition, when two main water heaters are set during the hot water supply standby and the incoming water flow rate is detected, if the incoming water flow rate is relatively low, one main hot water source is switched to a non-water-supplyable state according to the principle of control. The system is also accompanied by a control that allows water to flow through only the water heater, so that it is possible to reliably avoid the occurrence of a system down due to a failure of the incoming water flow rate sensor 41 and to concentrate water flow on one main water heater. Thus, the MOQ can be turned on promptly or the hot water supply operation can be stabilized.

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. That is, in the said embodiment, although the example which comprised the hot_water | molten_metal supply system by the two or more water heaters 3, 3, ... and the system controller 2 which controls these was shown, it is not restricted to this, Two or more of such A high-order system that includes two or more units of hot water supply systems, each of which includes a combination of a water heater and a system controller that controls them, and that controls each system controller (child system controller) of each unit of hot water system By providing a controller (parent system controller), the present invention can be applied to a hot water supply system that constitutes a so-called hierarchical control system. In addition, although two hot water heaters are set as the main hot water heaters during hot water standby, the present invention is not limited to this, and three or more hot water heaters can be set as the main hot water heaters. Furthermore, in the said embodiment, although the structure which provides the system controller 2 separately from several water heaters 3, 3, ... was shown, not only this but without providing the system controller 2 separately, the number control part 21 of FIG. The function can be provided in the individual controller 31 of any one of the water heaters 3.

3, 3a, 3b, 3c, 3d, 3e, 3f Water heater 5 Inlet path 6 Outlet path 21 Number control unit

Claims (4)

A plurality of water heaters installed in parallel between the water inlet path and the hot water outlet path, and the number of units connected to the plurality of water heaters to perform hot water supply operation for the plurality of water heaters. A hot water supply system configured to increase or decrease the number of hot water heaters to be operated in hot water supply according to a required amount of hot water supply.
A plurality of main water heaters that are maintained in a state where water can be passed during standby for hot water supply operation, and the water flow rate detected by one of the plurality of main water heaters satisfies the first water flow condition. In principle, the main control unit that switches and controls other main water heaters to a state in which water cannot pass through,
On the condition that the total flow rate of the water flow detected by each of the plurality of main water heaters satisfies the second water flow condition, the plurality of An exception control unit that maintains all of the main water heaters in a state that allows water to pass through,
A hot water supply system characterized by comprising: The hot water supply system according to claim 1,
In the second water flow condition, the total flow rate is switched from a state in which only one main water heater is allowed to pass water to a state in which one main water heater can be passed. The hot water supply system is equal to or greater than the determination flow rate for increasing the number of hot water supply operation. The hot water supply system according to claim 1 or 2,
Although the first water flow condition is smaller than the first predetermined flow rate that is a start condition of the hot water supply operation in the water heater, the state where the water flow rate is larger than the second predetermined flow rate that can be detected continues for the first determination time. Or a state where the flow rate is higher than the first predetermined flow rate continues for a second determination time. The hot water supply system according to claim 3,
The second determination time is a determination time for determining whether or not the second water flow condition is satisfied, and if the second water flow condition is satisfied before the second determination time elapses, A hot water supply system configured to cancel control by the principle control unit and execute control by the exception control unit.

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