JP2015059714A - Hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both suppression of delay in restart of hot water supply operation and suppression of deterioration of hot water tapping temperature, at the time of hot water re-tapping after stop of hot water tapping in an operation ON state, even when inflow water pressure to a hot water supply device is low.SOLUTION: When hot water tapping is stopped while a hot water supply device is in an operation ON state, an opening of a water amount adjusting valve is set at a standby opening P1. At the time of hot water re-tapping by faucet operation of a user and the like, when a flow rate Q reaches a minimum operation flow rate MOQ, hot water supply operation is started. In the case where the flow rate Q is lower than the MOQ, when a state in which the flow rate Q exceeds a detection threshold value of a low flow rate Q*(Q*<MOQ) continues for a certain time T1, the opening of the water amount adjusting valve is set at a standby opening P2 in which the flow rate increases more than that of the standby opening P1, and comparison between the flow rate Q and the MOQ is performed.

Description

  The present invention relates to a hot water supply apparatus, and more particularly to a hot water supply apparatus having a water amount adjustment valve.

  In a water heater, a configuration in which a water amount adjustment valve is provided for the purpose of preventing excessive outflow is known. For example, Japanese Patent No. 2526472 (Patent Document 1) includes a water amount detection device and a water amount adjustment valve in a water passage, and starts a hot water operation when the flow rate detected by the water amount detection device reaches the minimum operating flow rate (MOQ). A hot water supply device is described.

  In the hot water supply apparatus described in Patent Document 1, when the hot water is stopped by the user closing the currant or the like in the operation-on state, the opening amount of the water amount adjustment valve is controlled to a predetermined standby position opening degree and is in a standby state. It is described that it enters. When the hot water supply device is turned on again and the currant is opened again, it is confirmed that the flow state under the minimum operating flow rate MOQ has continued for a predetermined determination time, and the water amount adjustment valve is opened. The control for increasing the flow rate by driving is described.

  In Japanese Patent Publication No. 2-45781 (Patent Document 2), at the start of hot water supply of an instantaneous water heater, the flow rate is controlled by a water amount adjustment valve until a predetermined time elapses after the water amount sensor detects the flow rate. The control which restricts is described.

Japanese Patent No. 2526472 Japanese Examined Patent Publication No. 2-45781

  Even if the hot water supply device is in an operation-on state, when a hot water stop is detected, the hot water supply operation is stopped and the hot water supply device enters a standby state. In the standby state, the fuel supply to the heat source mechanism such as a gas burner is stopped, so that the input of the heat quantity to the heat exchanger is stopped.

  At the time of re-watering by the user's opening in the standby state, the hot water retained in the hot water supply apparatus in the standby state is first output. Furthermore, since the hot water supply operation is not started until the minimum operating flow rate MOQ is detected, the amount of heat is not input to the heat exchanger from a heat source mechanism such as a gas burner. Therefore, at the time of re-heating, if the amount of hot water until the temperature rise is actually started in response to detection of the minimum operation flow rate MOQ is too large with respect to the amount of heat retained in the hot water supply device in the standby state, the temperature of the hot water decreases. There is concern about inviting.

  In a hot water supply apparatus that is used in an environment where the incoming water pressure is low, for example, by being installed on the upper floor of a high-rise house, the initial flow rate at the time of re-watering becomes small, so there is a possibility that the minimum operating flow rate MOQ cannot be detected quickly. Thereby, since the restart of hot-water supply operation | movement is overdue, the possibility of the hot-water temperature fall at the time of the above-mentioned re-hot water increases. In particular, in recent years, there is a social background such as environment orientation, and the need for a compact hot water supply apparatus is also increasing. In a compact hot water supply apparatus, the amount of hot water retained in the standby state, that is, the retained heat amount is also reduced, so there is a further concern about the problem of a decrease in the temperature of the hot water at the time of re-heating.

  In the hot water supply apparatus described in Patent Document 1, even when the water pressure is low, the control of opening the water amount adjustment valve until the minimum operation flow rate MOQ is detected can ensure the minimum operation flow rate MOQ and quickly resume the hot water supply operation. Have been described. However, in Patent Document 1, the water amount adjustment valve is uniformly driven in the opening direction.

  Therefore, when the control of Patent Document 1 is applied to the compacted hot water supply apparatus described above, the minimum operating flow rate MOQ can be secured quickly at the time of re-watering at a low water pressure, while actually raising the temperature. There is a possibility that the temperature of the hot water is lowered due to an excessive amount of the hot water during

  The present invention has been made to solve such a problem, and even when the incoming water pressure to the hot water supply device is low, the hot water supply operation is resumed when the hot water is stopped after the hot water is stopped in the operation-on state. It is to control the opening of the water amount adjusting valve so as to achieve both the suppression of delay and the suppression of lowering of the tapping temperature.

  The hot water supply apparatus according to the present invention includes a heat exchanger, a water amount adjustment valve, a flow rate detector, and a control device. The heat exchanger is configured to heat the water passing through the water passage by the amount of heat generated by the heat source mechanism. The water amount adjustment valve adjusts the flow rate of the water channel. The flow rate detector detects the flow rate of the water passage. The control device controls the heat source mechanism and the water amount adjustment valve. The control device is configured to control the heat source mechanism so as to execute the hot water supply operation when a flow rate exceeding the minimum operating flow rate is detected by the flow rate detector, and to adjust the water amount after the hot water supply is stopped when the heat source mechanism is stopped. In the state where the valve is set to the first opening and the water amount adjustment valve is set to the first opening, the predetermined flow rate is lower than the minimum operating flow rate and lower than the minimum operating flow rate. And means for setting the water amount adjusting valve to a second opening degree at which the flow rate is increased from the first opening degree.

  According to the above hot water supply apparatus, after the hot water supply is stopped, the standby opening degree of the water amount adjustment valve provided for the re-hot water is set in two stages (first / second opening degree), so that the incoming water pressure is low. However, by switching the standby opening degree, it is possible to suppress the delay in passing the minimum operating flow rate (MOQ) and to suppress the amount of hot water until the temperature rise is resumed by the hot water supply operation. Therefore, even if the compacted hot water supply apparatus is used in an environment where the incoming water pressure is low, both the restart delay of the hot water supply operation and the reduction of the hot water temperature can be suppressed at the time of re-heating.

  Preferably, the control device controls the opening of the water amount adjusting valve in a direction in which the flow rate increases when the flow rate does not reach the minimum operating flow rate in a state where the water amount adjusting valve is set to the second opening degree. These means are further included.

  In this way, when the minimum operating water amount (MOQ) cannot be detected even if the water amount adjusting valve is set to the second opening, the flow rate can be increased by automatically controlling the opening of the water amount adjusting valve. . Therefore, even when the incoming water pressure is low, it is possible to suppress a delay in restarting the hot water supply operation during re-watering.

  More preferably, the first opening degree is set to an opening degree at which the minimum operating flow rate can pass through the water passage when the incoming water pressure to the hot water supply apparatus is a predetermined standard water pressure. The second opening degree is set to an opening degree at which the minimum operating flow rate can pass through the water passage when the incoming water pressure to the hot water supply apparatus is a predetermined minimum operating water pressure lower than the standard water pressure. The second opening is an opening whose flow rate is smaller than the maximum opening.

  With this configuration, even when the incoming water pressure is either a standard water pressure or a low water pressure (at the lowest operating water pressure), a delay in passing over the minimum operating flow rate (MOQ) is suppressed at the time of re-heating, and a hot water supply device It is possible to suppress an excessive amount of hot water until the temperature raising function is restored.

  According to this invention, even when the incoming water pressure of the hot water supply device is low, at the time of re-heating after hot water stop in the operation-on state, so as to achieve both suppression of restart delay of hot water supply operation and suppression of decrease in hot water temperature, The opening degree of the water amount adjustment valve can be controlled.

It is a schematic block diagram of the hot water supply apparatus which concerns on embodiment of this invention. It is a flowchart for demonstrating the opening degree control of the water quantity adjustment valve at the time of the re-watering in the operation-on state in the hot water supply apparatus which concerns on embodiment of invention. It is a rough operation | movement waveform at the time of re-watering in the operation-on state of the hot water supply apparatus which concerns on embodiment of this invention. It is a flowchart for demonstrating the modification of the opening degree control of the water quantity adjustment valve at the time of re-bathing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

FIG. 1 is a schematic configuration diagram of a hot water supply apparatus according to an embodiment of the present invention.
Referring to FIG. 1, hot water supply apparatus 100 according to an embodiment of the present invention includes hot water supply pipe 110, bypass pipe 120, gas burner 130, heat exchanger 140, gas proportional valve 150, and water amount adjustment valve 160. And the control device 200.

  The hot water supply pipe 110 is configured to connect from the water inlet to the hot water inlet. That is, the “water passage” is constituted by the hot water supply pipe 110. The water amount adjustment valve 160 is inserted and connected to the hot water supply pipe 110. The flow rate of the hot water supply pipe 110 can be controlled by adjusting the opening of the water amount adjustment valve 160 by the control device 200. At the time of normal hot water supply, the control device 200 has an amount of water for the function of preventing excessive outflow (maximum flow rate restriction and adjustment of the hot water temperature), that is, so that the flow rate Q (l / min) of the hot water supply pipe 110 does not become excessive. The opening degree of the regulating valve 160 is controlled.

  The gas burner 130 generates heat by burning a mixture of gas supplied from a gas pipe (not shown) and air supplied from a combustion fan (not shown). The gas pressure supplied to the gas burner 130 (that is, the gas supply amount per unit time) is controlled according to the opening degree of the gas proportional valve 150. Note that the amount of air supplied from the combustion fan is controlled so as to maintain a constant air-fuel ratio in combustion in the gas burner 130.

  The amount of heat generated by the combustion in the gas burner 130 is used to increase the temperature of the water flowing through the hot water supply pipe 110 via the heat exchanger 140. That is, the gas burner 130 is an example of a “heat source mechanism”.

  In addition, although the hot water supply apparatus 100 illustrated in FIG. 1 is configured to mix and output the output of the heat exchanger 140 and the output of the bypass pipe 120 for preventing the heat exchanger 140 from passing therethrough. The bypass pipe 120 may not be arranged.

  In addition to the configuration example of FIG. 1, a bypass flow rate adjustment valve may be provided in the bypass pipe 120. Alternatively, it is possible to provide a hot water / water mixing ratio adjusting valve at the junction 145 between the bypass pipe 120 and the hot water supply pipe 110. In these configurations, the can body temperature sensor is provided downstream of the heat exchanger 140 and upstream of the junction 145.

  The hot water supply pipe 110 is provided with a flow rate sensor 210 and temperature sensors 220 and 230. The flow rate sensor 210 detects the flow rate Q of the hot water supply pipe 110. The temperature sensor 220 is provided on the upstream side of the heat exchanger 140 and detects the incoming water temperature Tc. The temperature sensor 230 is provided on the downstream side of the heat exchanger 140 and detects the tapping temperature Th. The detected flow rate Q, incoming water temperature Tc and outgoing hot water temperature Th are input to the control device 200. That is, the flow sensor 210 corresponds to an embodiment of a “flow detector”.

  The control device 200 is configured by, for example, a microcomputer and controls the operation of the hot water supply device 100. Specifically, when the hot water supply device 100 is set to the operation-on state by a user operation, the flow rate Q detected by the flow sensor 210 is larger than a predetermined minimum operating flow rate MOQ, that is, the minimum operating flow rate MOQ. The hot water supply operation is executed while a super flow is detected. When the hot water supply operation is performed, the amount of heat is input to the heat exchanger 140 by the combustion of the gas in the gas burner 130. It should be noted that the minimum operating flow rate has two types of hysteresis, MOQ (ON flow rate) for starting combustion (hot water supply operation) and MOQ (OFF flow rate) for stopping combustion (hot water supply operation). It is preferable to provide (MOQ (on flow rate)> MOQ (off flow rate)). In this way, it is possible to prevent hunting in which the start and stop of combustion are frequently repeated in a short time.

  During the hot water supply operation, control device 200 executes gas supply to gas burner 130 in accordance with temperature control for controlling tapping temperature Th according to set hot water temperature Tr. For example, the control device 200 calculates a required generated heat amount that is the amount of heat generated in the gas burner 130 required for the hot water temperature control, and controls the opening of the gas proportional valve 150 according to the required generated heat amount.

  When the user closes the currant or the like while the hot water supply device 100 is in the operation-on state, the control device 200 detects the hot water supply stop and stops the hot water supply operation in response to the flow rate Q falling below the minimum operating flow rate MOQ. . Thereby, the hot-water supply apparatus 100 will be in a standby state. In the standby state, the gas supply to the gas burner 130 is stopped, so that the heat source for the hot water is only the amount of heat retained in the hot water supply apparatus 100.

  When the user opens the currant or the like after stopping the hot water supply, the flow of the hot water supply pipe 110 is resumed by the incoming water pressure. The flow rate Q at this time is determined by the opening degree of the water amount adjusting valve 160, the opening degree of the currant and the like and the incoming water pressure. When re-heating hot water after such hot water is stopped, the hot water remaining in the hot water supply pipe 110 in the standby state is first output from the hot water supply device 100. At the time of re-heating, the hot water supply operation is not resumed until the flow rate Q exceeds the minimum operation flow rate MOQ.

  Therefore, at the time of re-watering, the opening amount of the water amount adjustment valve 160 is appropriately controlled so that the amount of hot water discharged until the temperature rise is resumed in response to detection of the minimum operating flow rate MOQ does not decrease. It is necessary to.

  FIG. 2 is a flowchart for explaining the opening degree control of the water amount adjusting valve at the time of re-watering in the hot water supply apparatus according to the embodiment of the present invention.

  Referring to FIG. 2, when hot water supply device 100 is in an operation-on state and hot water supply is stopped (YES determination in S100), control device 200 controls water amount adjustment valve 160 in a standby state to prepare for re-hot water. Start. For example, when the hot water supply apparatus 100 is in the operation-on state and the flow rate Q detected by the flow sensor 210 is lower than the minimum operating flow rate MOQ, step S100 is determined as YES.

  When NO is determined in step S100, the control of the water amount adjustment valve 160 after step S110 is not executed. When water heater 100 is turned off, water amount adjustment valve 160 is fully opened.

  In a standby state (when YES is determined in S100), control device 200 sets water amount adjustment valve 160 at a predetermined standby opening P1 in preparation for re-draining (S110).

  For example, standby opening degree P1 is an intermediate opening degree between fully closed (minimum opening degree of flow) and fully open (maximum opening degree of flow rate), and when the incoming water pressure to hot water supply device 100 is a predetermined standard water pressure. The opening is set such that the flow rate Q reaches the minimum operating flow rate MOQ. The standard water pressure corresponds to a recommended incoming water pressure as a specification value of the hot water supply device 100. The standby opening degree P1 can be obtained in advance by an actual machine experiment or the like.

  In step S120, the control device 200 compares the flow rate Q with the minimum operating flow rate MOQ according to the detected value of the flow rate sensor 210 when the water amount adjustment valve 160 is set to the standby opening degree P1 (S110).

  If the incoming water pressure is secured at about the standard water pressure, the flow rate Q reaches the minimum operating flow rate MOQ at this stage (YES in S120). For this reason, the control apparatus 200 can detect the flow exceeding the minimum operating flow rate MOQ and can restart the hot water supply operation (S160). As a result, the amount of heat is input from the gas burner 130 to the heat exchanger 140, so that the temperature rise is resumed.

  When the standard water pressure at which step S120 is determined to be YES, the temperature rise is resumed in a relatively short time even at the time of re-heating. At this time, the flow rate Q in the standby state until the hot water supply operation is started is limited by setting the water amount adjusting valve 160 to the standby opening degree P1, so that the temperature of the discharged hot water decreases when the hot water is discharged again. Can be prevented. In order to more reliably prevent a decrease in the hot water temperature, the opening amount of the water amount adjustment valve 160 is reduced during a predetermined period immediately after the start of the hot water supply operation. Specifically, the amount of water in the opening direction (flow rate increasing direction) It is preferable to limit the driving speed or opening of the regulating valve 160.

  On the other hand, when the water pressure to the hot water supply device 100 is low due to installation on the upper floor of a high-rise house or the like, the flow rate Q is minimum in the state where the water amount adjustment valve 160 is set to the standby opening degree P1 (S110). There is a possibility that the operating flow rate MOQ may not be reached (that is, step S120 is NO). In this case, since the flow exceeding the minimum operating flow rate MOQ is not detected, the hot water supply operation cannot be resumed in step S160.

  When Q> MOQ is not detected (when NO is determined in step S120), control device 200 compares flow rate Q with low flow rate detection threshold Q * in step S130. The threshold value Q * is a predetermined value lower than the minimum operating flow rate MOQ. Q * is set so that even when the incoming water pressure is low, it can be detected that the flow is generated in the state where the water amount adjustment valve 160 is set to the standby opening degree P1 (S110). For example, while MOQ is about 1.7 (L / min), Q * can be set to about 0.25 (L / min).

  When the state of Q> Q * continues for a predetermined fixed time T1 (for example, T1 = 1.5 seconds), control device 200 detects a flow at a low flow rate and determines YES in step S130. When the flow at low flow rate is not detected (NO determination in S130), control device 200 returns the process to step S110 and maintains the opening of water amount adjustment valve 160 at standby opening P1.

  When the flow at a low flow rate is detected (when YES is determined in S130), control device 200 sets the opening of water amount adjustment valve 160 to standby opening P2 (S140). For example, the standby opening degree P2 is such an opening degree that the flow rate Q reaches the minimum operating flow rate MOQ when the predetermined water pressure is lower than the standard water pressure (for example, the minimum operating water pressure as the spec value of the water heater 100). Is set. Similarly to the standby opening degree P1, the standby opening degree P2 can be obtained in advance by an actual machine experiment or the like. The standby opening P2 is an intermediate opening similarly to the standby opening P1, and is set to an opening having a smaller flow rate than the fully open (maximum flow opening).

  Further, in step S150, control device 200 compares flow rate Q with minimum operating flow rate MOQ according to the detected value of flow rate sensor 210 in a state where water amount adjustment valve 160 is set to standby opening degree P2 (S140). When the flow rate Q reaches the minimum operating flow rate MOQ (when YES is determined in S150), the control device 200 detects the flow exceeding the minimum operating flow rate MOQ and restarts the hot water supply operation (S160). On the other hand, until the flow rate Q reaches the minimum operating flow rate MOQ (NO determination in S150), the opening degree of the water amount adjustment valve 160 is maintained at the standby opening degree P2 (S140).

  FIG. 3 is a schematic operation waveform at the time of re-watering in the operation-on state of the hot water supply apparatus according to the embodiment of the invention. That is, FIG. 3 shows the operation of hot water supply apparatus 100 when water amount adjustment valve 160 is controlled according to the flowchart shown in FIG.

  Referring to FIG. 3, in the standby state after stopping hot water, the opening of water amount adjustment valve 160 is set to standby opening P1. When the user opens the currant at time t0, the hot water supply pipe 110 flows (Q> 0). At this time, when the incoming water pressure to the hot water supply apparatus 100 is low, the flow rate Q at the standby opening P1 does not reach the minimum operating flow rate MOQ.

  However, the flow rate Q reaches a threshold value Q * set so that the flow can be detected even at the time t1 even when the incoming water pressure is low at the standby opening P1. Therefore, it is possible to detect a flow at a low flow rate at time t2 when a certain time T1 has elapsed from time t1 (S130 in FIG. 2).

  Accordingly, the opening of the water amount adjustment valve 160 is opened from the standby opening P1 to the standby opening P2. At time t3, the opening of the water amount adjustment valve 160 reaches the standby opening P2. Even after time t2, detection of the minimum operating flow rate MOQ by S150 in FIG. 2 is continuously performed.

  The flow rate Q gradually increases in accordance with the increase in the opening degree of the water amount adjustment valve 160 after time t2. When the flow rate Q reaches the minimum operating flow rate MOQ at time t4, a hot water supply operation is resumed by detecting a flow exceeding the minimum operating flow rate MOQ (S160 in FIG. 2). Then, when the combustion of the gas burner 130 is started with a certain time delay (ΔT), the input heat quantity HT to the heat exchanger 140 rises at time t5. Therefore, after time t5, hot water supply apparatus 100 recovers the temperature raising function by heat exchanger 140. That is, the temperature rise is actually started.

  In FIG. 3, as a comparative example, the degree of opening of the water amount adjustment valve 160 is uniformly opened (flow increasing direction) until the minimum operating flow rate MOQ is detected in response to detection of flow at a low flow rate at time t2. The control to drive to is indicated by a dotted line. The comparative example is similar to the opening degree control of the water amount adjustment valve in the standby state described in Patent Document 1.

  Since a constant response delay due to the inertia of the fluid occurs between the change in the flow rate of the water amount adjustment valve 160 and the change in the flow rate Q, the flow rate Q gradually increases even when the opening amount of the water amount adjustment valve 16 is constant. . However, in the present embodiment, an increase in the flow rate Q can be suppressed by maintaining the standby opening degree P2. On the other hand, when the water amount adjustment valve 160 is controlled according to the comparative example, there is a concern that the flow rate Q after the time t3 increases. That is, according to the comparative example, when the opening degree of the water amount adjusting valve 160 is uniformly changed in the opening direction, the minimum operating flow rate MOQ is detected by increasing the rate of increase of the flow rate Q compared to the present embodiment. There is a concern that the amount of tapping water (corresponding to the integrated value of the flow rate Q) will be excessive. Furthermore, the amount of hot water in the time delay (time t4 to t5) from the detection of the minimum operating flow rate MOQ until the actual temperature increase is started is compared with the case where the standby opening P2 is maintained as in the present embodiment. There is a concern that it will grow.

  Therefore, in the opening degree control of the water amount adjusting valve 160 according to the comparative example, although the detection of the minimum operating flow rate MOQ is quicker than the control according to the present embodiment, the hot water supply device 100 is actually heated at the time of re-heating. There is a possibility that the amount of hot water until the start of heating will be excessive with respect to the amount of heat retained by hot water supply apparatus 100 in the standby state. As a result, if the hot water supply apparatus 100 is made compact, the hot water temperature may decrease during re-hot water.

  On the other hand, in the hot water supply apparatus according to the present embodiment, the standby opening degree of the water amount adjustment valve 160 provided for re-draining is set in two stages, so that the standby opening degree can be reduced even when the incoming water pressure is low. By switching, it is possible to suppress the flow delay exceeding the minimum operating flow rate MOQ, and to suppress the amount of hot water until the minimum operating flow rate MOQ is detected and the hot water supply device 100 restarts the temperature rise. Therefore, even when the compacted hot water supply apparatus is used in an environment where the incoming water pressure is low, both the delay in passing over the minimum operating flow rate MOQ and the reduction in the temperature of the discharged hot water can be achieved during re-heating.

  In particular, the standby opening degree P1 is set to an opening degree for detecting the minimum operating flow rate MOQ at the standard water pressure, and the standby opening degree P2 is detected for the minimum operating flow rate MOQ at the low water pressure (at the minimum operating water pressure). Regardless of whether the incoming water pressure is standard water pressure or low water pressure (at the lowest operating water pressure), the delay in passing the minimum operating flow rate MOQ can be suppressed and the temperature rising It is possible to prevent the amount of hot water until the water recovers from becoming excessive.

  In order to reliably restart the hot water supply operation at the time of re-watering even when the incoming water pressure to the hot water supply apparatus 100 is lower than expected, the opening degree control of the water amount adjustment valve 160 may be modified as follows.

  FIG. 4 is a flowchart for explaining a modification of the opening control of the water amount adjusting valve at the time of re-watering in the operation-on state in the hot water supply apparatus according to the embodiment of the invention.

  FIG. 4 is compared with FIG. 3, in the water amount adjustment valve opening control according to the modified example, when the minimum operation flow rate MOQ is not detected even when the water amount adjustment valve 160 is set to the standby opening degree P <b> 2 (NO determination in S <b> 150). ), Steps S170 and S180 are further executed. Since the processes in steps S100 to S160 in FIG. 4 are the same as those in FIG. 2, detailed description will not be repeated.

  In step S170, the control device 200 determines whether or not a certain time T2 has elapsed since the water amount adjustment valve 160 was set to the standby opening degree P2. That is, step S170 is determined to be YES when the elapsed time from time t3 in FIG. 3 exceeds a certain time T2, but is determined to be NO until then.

  The control device 200 returns the process to step S140 until the elapsed time exceeds the predetermined time T2 (when NO is determined in S170), and maintains the opening of the water amount adjustment valve 160 at the standby opening P2.

  On the other hand, when the elapsed time exceeds the predetermined time T2 (when YES is determined in S170), the control device 200 advances the process to step S180 and increases the opening of the water amount adjustment valve 160. That is, the opening degree of the water amount adjustment valve 160 is driven in the direction in which the flow rate Q increases.

  The detection of the minimum operating flow rate in step S150 is repeatedly executed at a constant period until Q> MOQ is detected in both the YES determination and the NO determination in step S170.

  Therefore, according to the opening control of the water amount adjusting valve according to the modification shown in FIG. 4, since the incoming water pressure to the hot water supply device 100 is lower than expected, the water amount adjusting valve 160 is set to the standby opening P2 when re-watering. If the minimum operating flow rate MOQ is not detected even after setting, the opening of the water amount adjusting valve 160 can be automatically increased. Therefore, in addition to the effect of the opening control of the water amount adjusting valve shown in FIG. 2, even when the incoming water pressure is lower than the assumed water pressure when setting the standby opening P2, the minimum operating flow rate MOQ is set at the time of re-watering. Can be detected. That is, it is possible to more reliably return from the standby state and resume the hot water supply operation for re-watering.

  In the present embodiment, the gas burner 130 is exemplified as the “heat source mechanism” that generates the amount of heat for heating the water in the hot water supply pipe 110, but the application of the present invention is not limited to such a configuration. Make sure that there are no points. That is, any “heat source mechanism” may be employed as long as it is configured to be controlled by the control device 200 so as to be stopped in a standby state and to be operated during a hot water supply operation and to input a heat amount to the heat exchanger. Is possible. For example, instead of the gas burner, an arbitrary heat source such as an oil burner for burning oil or a heat pump mechanism can be applied.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Hot-water supply apparatus, 110 Hot-water supply piping, 120 Bypass piping, 130 Gas burner, 140 Heat exchanger, 150 Gas proportional valve, 160 Water quantity adjustment valve, 200 Control apparatus, 210 Flow rate sensor, 220, 230 Temperature sensor, Q flow rate.

Claims (3)

A heat exchanger configured to heat the water passing through the water passage by the amount of heat generated by the heat source mechanism;
A water amount adjusting valve for adjusting the flow rate of the water passage;
A flow rate detector for detecting the flow rate of the water passage;
A control device for controlling the heat source mechanism and the water amount adjusting valve,
The controller is
Means for controlling the heat source mechanism to perform a hot water supply operation when a flow rate exceeding a minimum operating flow rate is detected by the flow rate detector;
Means for setting the water amount adjusting valve to the first opening after the hot water supply is stopped when the heat source mechanism is stopped;
In a state where the water amount adjusting valve is set to the first opening, when the flow rate is lower than the minimum operating flow rate, and the flow rate exceeds a predetermined flow rate lower than the minimum operating flow rate, the water amount adjusting valve And a means for setting the second opening at which the flow rate increases more than the first opening. The controller is
In the state where the water amount adjusting valve is set to the second opening, when the flow rate does not reach the minimum operating flow rate, the opening of the water amount adjusting valve is controlled to increase the flow rate. The hot water supply apparatus according to claim 1, further comprising means. The first opening degree is set to an opening degree at which the minimum operating flow rate can pass through the water passage when the incoming water pressure to the hot water supply device is a predetermined standard water pressure.
The second opening degree is set to an opening degree at which the minimum operating flow rate can pass through the water passage when the incoming water pressure to the hot water supply device is a predetermined minimum operating water pressure lower than the standard water pressure. And the said 2nd opening degree is a hot water supply apparatus of Claim 1 or 2 which is an opening degree with a flow volume smaller than the opening degree by which the flow volume of the said water quantity adjustment valve becomes the maximum.

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