JP6308029B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type water heater.

  Patent Document 1 listed below discloses a hot water storage type water heater having a function of determining that there is no water in the circulation pump during an air bleeding operation for extracting air in the circulation circuit. Yes. In the invention of Patent Document 1, “with water”, “without water DRY”, and “without water WET” are detected by detecting the rotation speed of the circulation pump in a state where the duty ratio of the signal for driving the circulation pump is constant. The state of is determined. Here, “with water” is a state in which the inside of the circulation pump is filled with water. “Waterless WET” is a state in which there is no water inside the circulation pump, and the space between the pump rotating shaft and the bearing is slightly wet. “Waterless DRY” is a state where there is no water inside the circulation pump and the space between the pump rotating shaft and the bearing is dry. In general, in the manufacturing process of the circulation pump, water is put inside to check whether the circulation pump operates normally. For this reason, among the circulating pumps shipped, there are pumps whose pump rotation shafts are still wet with water introduced at the time of inspection. If the pump rotation shaft is wet in this way, a “waterless WET” condition can occur.

JP 2010-78277 A

  In the invention of Patent Document 1, since the pump rotational speed increases in the order of “waterless WET”, “water present”, and “waterless DRY”, the pump rotational speed is a predetermined value α (for example, 5500 rpm) or more, When the pump rotation speed is a predetermined value β (for example, 1000 rpm) or less, it is determined that there is no water inside the circulation pump. However, since the difference between the pump speed at the time of “without water WET” and the pump speed at the time of “with water” is relatively small, there is a possibility of erroneous determination. Further, in the invention of Patent Document 1, it is necessary to wait until the pump rotational speed is stabilized in order to discriminate between “waterless WET” and “water present” which are unlikely to cause a difference in pump rotational speed. After the circulation pump is started, it takes some time for the pump rotation speed to stabilize. Therefore, in the case of “no water DRY”, the circulating pump is operated for a long time in a state where the pump rotating shaft is not lubricated with water, so that the wear of the pump rotating shaft proceeds.

  The present invention has been made in order to solve the above-described problems, and it is possible to accurately determine that there is no water in the circulation pump and to suppress wear of the pump rotating shaft, and to store the hot water supply hot water. The purpose is to provide a machine.

A hot water storage type water heater according to the present invention includes a hot water storage tank, a circulation pump that circulates hot water in a circulation circuit that connects the heating means for heating water and the hot water storage tank, and a rotation speed detection means that detects the rotation speed of the circulation pump. And a control means for controlling the circulation pump, the control means, as the first control, after the start of the circulation pump, a state where the number of rotations of the circulation pump is lower than the first threshold continues for the first determination time or more In this case, it is determined that the circulation pump is stopped and abnormal, and if not, control is performed so that the circulation pump is operated continuously. From the start of the first control, a second determination time longer than the first determination time is performed. When the circulating pump continues to operate even after the elapse of time, the control means performs second control for determining whether the rotation speed of the circulating pump is lower than the second threshold, and the control means performs the second control. In the circulation pump When it is determined that the number is lower than the second threshold, the first control is performed again from the beginning, and the number of revolutions of the circulation pump in a state where the inside of the circulation pump is filled with water is the first threshold and the second The rotation speed of the circulation pump is higher than the first threshold value and the second threshold value when there is no water inside the circulation pump and the space between the pump rotation shaft and the bearing is wet. The rotation speed of the circulation pump when there is no water inside the circulation pump and the space between the pump rotation shaft and the bearing is dry is lower than the first threshold value and the second threshold value.

  According to the present invention, it can be accurately determined that there is no water inside the circulation pump, and wear of the pump rotating shaft can be suppressed.

It is a block diagram which shows the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the flowing water path | route at the time of hot water filling of the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the flowing water path | route at the time of the air bleeding operation | movement of the hot water storage type water heater of Embodiment 1 of this invention. It is a characteristic line figure which shows the example of the driving | running characteristic of the circulation pump at the time of the air bleeding operation | movement of the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the example of the time change of the pump rotation speed at the time of the 1st control which determines that it is a state without water inside the circulation pump of the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the example of the time change of the pump rotation speed when the state of the circulation pump of the hot water storage type water heater of Embodiment 1 of this invention changes from "waterless WET" to "waterless DRY". It is a flowchart of the process which a control part performs by the 1st control of the hot water storage type water heater of Embodiment 1 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a hot water storage type water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, the hot water storage type water heater 1 of the first embodiment includes a hot water storage tank unit 5 and a heat pump unit 6. The hot water storage tank unit 5 and the heat pump unit 6 are connected via a heat pump inlet pipe 41a, a heat pump outlet pipe 41b, and electrical wiring (not shown). The hot water storage tank unit 5 includes a controller 70. The remote controller 71 is communicably connected to the control unit 70. Although illustration is omitted, the remote controller 71 includes an operation unit operated by a user and a display unit for displaying information such as an operating state of the hot water storage hot water heater 1. The control unit 70 includes, for example, a microcomputer, and includes a storage unit including a ROM, a RAM, a nonvolatile memory, and the like, an arithmetic processing device (CPU) that executes arithmetic processing based on a program stored in the storage unit, Control means comprising an input / output port for inputting / outputting external signals to / from the arithmetic processing unit. Operations of various valves, pumps, compressors, and the like included in the hot water storage tank unit 5 and the heat pump unit 6 are controlled by a control unit 70 electrically connected thereto.

  The heat pump unit 6 is a heating unit that heats water guided from the hot water storage tank unit 5. The heat pump unit 6 operates a refrigeration cycle (heat pump cycle) in a refrigerant circuit in which a compressor 61, a water-refrigerant heat exchanger 62, an expansion valve 63, and an evaporator 64 are annularly connected by a refrigerant circulation pipe 65. . The water-refrigerant heat exchanger 62 heats water by exchanging heat between the high-temperature and high-pressure refrigerant compressed by the compressor 61 and the water introduced from the hot water storage tank unit 5. A heat pump outlet temperature sensor 66 provided in the heat pump outlet pipe 41 b detects the temperature of the high-temperature water heated by the water-refrigerant heat exchanger 62.

  The hot water storage tank unit 5 includes a hot water storage tank 10 for storing hot water. A water supply pipe 7 for supplying water from a water source such as a water supply is connected to the lower part of the hot water storage tank 10. A first tank upper pipe 42 a and a second tank upper pipe 42 b are connected to the upper part of the hot water storage tank 10. The hot water supply pipe 8 branches off from the second tank upper pipe 42b. At the time of hot water supply, hot water stored in the hot water storage tank 10 is taken out via the hot water supply pipe 8. The hot water supply pipe 8 is provided with a hot water supply flow rate sensor 54 and a hot water supply temperature sensor 55. The high temperature water heated by the heat pump unit 6 flows into the upper part of the hot water storage tank 10 from the first tank upper pipe 42a or the second tank upper pipe 42b. The low temperature water supplied from the water source flows into the lower part of the hot water storage tank 10 from the water supply pipe 7. In the hot water storage tank 10, a temperature stratification can be formed in which the upper side is hot and the lower side is low. A plurality of hot water storage temperature sensors 11 and 12 are attached to the surface of the hot water storage tank 10 at positions having different heights. By detecting the temperature distribution in the vertical direction of the hot water storage tank 10 with these hot water storage temperature sensors 11, 12, the amount of stored hot water and the amount of heat storage in the hot water storage tank 10 can be detected.

  The hot water storage tank unit 5 further includes a circulation pump 21 and a use side heat exchanger 22. The circulation pump 21 is a pump that circulates hot water in a circulation circuit that connects the hot water storage tank 10 and the heat pump unit 6. Circulation pump 21 incorporates a rotation sensor 23 that detects the number of rotations (rotation speed). The rotational speed of the circulation pump 21 is hereinafter referred to as “pump rotational speed”. Circulation pump 21 in the first embodiment is a pulse width modulation (PWM) control type DC pump that is driven by a direct current motor and whose capacity can be adjusted by changing the duty ratio of the drive signal. However, the type and control method of the motor of the circulation pump in the present invention are not limited to those described above, and various types and methods can be applied.

  The use-side heat exchanger 22 uses the high-temperature water supplied from the hot water storage tank 10 or the heat pump unit 6 to heat the water to be heated on the secondary side (for example, bathtub circulating water, heating circulating water, etc.). It is an exchanger. In the first embodiment, as a secondary side configuration of the use-side heat exchanger 22, a bath circulation circuit 51 that circulates hot water in the bathtub 100 (hereinafter referred to as “tub water”) will be described as an example. . That is, in the first embodiment, the use side heat exchanger 22 is installed in the middle of the bath circulation circuit 51. The bath circulation circuit 51 includes a bath return pipe 56 and a bath going pipe 57. The bath return pipe 56 connects between the bathtub adapter 80 installed in the bathtub 100 and the secondary side inlet of the use side heat exchanger 22. The bath piping 57 connects between the secondary side outlet of the use side heat exchanger 22 and the bathtub adapter 80. A bath circulation pump 52 that circulates bathtub water, a bath outlet temperature sensor 53 that detects the temperature of bath water discharged from the bath 100, and a bath water circulation flow rate are provided in the middle of the bath return pipe 56 of the bath circulation circuit 51. A flow switch 58 that detects the presence or absence of the circulation of the bath water is installed by turning on the switch when it becomes a predetermined value or more.

  The hot water storage tank unit 5 further includes a first three-way valve 31, a second three-way valve 32, a four-way valve 33, and a bath hot water supply electromagnetic valve 34. The first three-way valve 31 and the second three-way valve 32 are flow path switching means having two inlets (a port and b port) through which hot water flows and one outlet (c port) through which hot water flows out. is there. The first three-way valve 31 and the second three-way valve 32 are capable of switching the hot water path so that hot water flows from either the a port or the b port. The first three-way valve 31 and the second three-way valve 32 can be further switched to a state in which the a port, the b port, and the c port communicate with each other. The four-way valve 33 is a flow path switching means having two inlets (b port and c port) through which hot water flows and two outlets (a port and d port) through which hot water flows out. The four-way valve 33 can switch the flow path form among three paths, that is, an ab path, a dd path, and a cd path. The bath hot water solenoid valve 34 is arranged in the middle of the bath hot water flow passage 35. The bath hot water supply channel 35 connects between the second tank upper pipe 42 b and the bath piping 57 of the bath circulation circuit 51. The bath hot water solenoid valve 34 is opened when the hot water is supplied to the bathtub 100.

  The heat pump inlet pipe 41 a described above connects between the c port of the second three-way valve 32 and the water inlet of the heat pump unit 6. The circulation pump 21 is disposed in the middle of the heat pump inlet pipe 41a. The heat pump outlet pipe 41 b connects between the water outlet of the heat pump unit 6 and the c port of the four-way valve 33. The second tank upper pipe 42 b connects between the upper part of the hot water storage tank 10 and the b port of the first three-way valve 31. One end of the first tank upper pipe 42 a is connected to the hot water storage tank 10 at a position below the connection position between the second tank upper pipe 42 b and the hot water storage tank 10. The other end of the first tank upper pipe 42 a is connected to the a port of the first three-way valve 31.

  The hot water storage tank unit 5 further includes a tank lower pipe 40, a tank return pipe 43, a heat source water inlet pipe 44 a, a heat source water outlet pipe 44 b, a bypass pipe 45 and an upper return pipe 46. The tank lower pipe 40 connects between the lower part of the hot water storage tank 10 and the a port of the second three-way valve 32. One end of the tank return pipe 43 is connected to the a port of the four-way valve 33. The other end of the tank return pipe 43 is connected to the hot water storage tank 10 at a position above the connection position between the tank lower pipe 40 and the hot water storage tank 10. The heat source water inlet pipe 44 a connects between the c port of the first three-way valve 31 and the primary side inlet of the use side heat exchanger 22. The heat source water outlet pipe 44 b connects between the primary side outlet of the use side heat exchanger 22 and the b port of the second three-way valve 32. The bypass pipe 45 branches from a heat pump inlet pipe 41 a between the circulation pump 21 and the water inlet of the heat pump unit 6, and is connected to the b port of the four-way valve 33. The upper return pipe 46 branches from the middle of the second tank upper pipe 42 b and is connected to the d port of the four-way valve 33.

  In the first embodiment, the tank lower pipe 40, the heat pump inlet pipe 41a, the heat pump outlet pipe 41b, the upper return pipe 46, and the first tank upper pipe 42a constitute a first circulation circuit 47. The tank lower pipe 40, the heat source water outlet pipe 44b, the heat source water inlet pipe 44a, and the first tank upper pipe 42a constitute a second circulation circuit 48.

  FIG. 2 is a diagram showing a flowing water path when the hot water storage type water heater 1 of the first embodiment is filled. As shown in FIG. 2, when hot water is filled, the hot water supply solenoid valve 34 is opened, so that the hot water in the hot water storage tank 10 passes through the hot water supply passage 35, the bath return pipe 56, the bath return pipe 57, and the bathtub adapter 80. It passes and is supplied to the bathtub 100. A mixing valve (not shown) that adjusts the hot water filling temperature by mixing low temperature water from the water source with hot water supplied from the hot water storage tank 10 is provided in the middle of the hot water supply flow path 35.

  In the case of operating the hot water storage type hot water heater 1 for the first time after the completion of the installation work of the hot water storage type water heater 1, the installation worker or the like removes the air inside the first circulation circuit 47 and the second circulation circuit 48. In addition, the air bleeding operation is performed. FIG. 3 is a diagram illustrating a flowing water path during the air bleeding operation of the hot water storage type hot water heater 1 according to the first embodiment. The operation of the air bleeding operation will be described with reference to FIG. In the first three-way valve 31 and the second three-way valve 32, the a port, the b port, and the c port communicate with each other. The four-way valve 33 is in a state of communicating between the c port and the d port. By driving the circulation pump 21 in such a state, the low-temperature water supplied from the water supply pipe 7 into the hot water storage tank 10 is circulated through the first circulation circuit 47 and the second circulation circuit 48. That is, the low temperature water is recirculated from the lower part of the hot water storage tank 10 to the upper part of the hot water storage tank 10 via the heat pump unit 6, and the use side heat exchanger is branched from the first circulation circuit 47. 22 and flows through a second circulation circuit 48 that joins the first circulation circuit 47 at the position of the second three-way valve 32. The control unit 70 determines a target rotation speed during the air bleeding operation, and controls the operation of the circulation pump 21 so as to continue for a certain period of time so as to reach the target rotation speed. By carrying out such an air venting operation, the air existing in the first circulation circuit 47 and the second circulation circuit 48 can be released into the hot water storage tank 10.

  There is a possibility that after the installation of the hot water storage type hot water heater 1 is completed, before the hot water storage tank 10 is supplied with water, the air bleeding operation is performed. In that case, the circulation pump 21 is driven in a state where there is no water inside the circulation pump 21.

  FIG. 4 is a characteristic diagram showing an example of operating characteristics of the circulation pump 21 during the air bleeding operation of the hot water storage type hot water heater 1 according to the first embodiment. FIG. 4 shows the relationship between the duty ratio of the drive signal input to the circulation pump 21 and the pump rotation speed. As shown in FIG. 4, the operation characteristics of the circulation pump 21 during the air bleeding operation include three states of “with water”, “without water WET”, and “without water DRY”. Here, “with water” is a state in which the inside of the circulation pump 21 is filled with water. “Waterless WET” is a state where there is no water inside the circulation pump 21 and the pump rotating shaft and the bearing are slightly wet. The “waterless DRY” is a state where there is no water inside the circulation pump 21 and the space between the pump rotating shaft and the bearing is dry. In general, in the manufacturing process of the circulation pump 21, it is inspected whether or not the circulation pump 21 operates normally by putting water therein. For this reason, among the circulating pumps 21 that have been shipped, there are pumps whose pump rotating shafts are still wet with water that has been put in during inspection. In that case, a “waterless WET” state may occur.

  In the following description, the duty ratio of the drive signal input to the circulation pump 21 is simply referred to as “duty ratio”. As shown in FIG. 4, in “with water”, when the duty ratio increases, the pump rotation speed increases in proportion to the duty ratio. In “waterless WET”, the load of the circulation pump 21 is small, and a lubricating action of water exists between the pump rotation shaft and the bearing. As a result, in “waterless WET”, when the duty ratio increases, the pump rotation speed increases more than “water present”. However, when the duty ratio reaches a certain value or more, a difference occurs between the rotation cycle of the motor of the circulation pump 21 and the rotation cycle of the impeller, thereby causing a phenomenon that the pump rotation speed decreases. In “waterless DRY”, there is no lubrication of water between the pump rotation shaft and the bearing, so even if the duty ratio is increased, only the rotational resistance of the circulation pump 21 is increased. As a result, in “waterless DRY”, the pump rotational speed is substantially constant at the lower rotational speed regardless of the duty ratio.

  FIG. 5 shows an example of a temporal change in the number of revolutions of the pump in the first control for determining that there is no water in the circulation pump 21 of the hot water storage hot water supply device 1 according to the first embodiment. FIG. The controller 70 drives the circulation pump 21 with the duty ratio fixed at a constant value in the first control. As shown in FIG. 5, when the state where the pump speed is lower than the first threshold continues for the first determination time or longer, the control unit 70 determines “no water DRY” and stops the circulation pump 21. Thus, by detecting “waterless DRY” and stopping the circulation pump 21, wear of the rotating shaft of the circulation pump 21 can be suppressed. The first determination time is preferably shorter than the time until the pump rotation speed is stabilized (converged) after the circulation pump 21 is started in the case of “with water”. By shortening the first determination time in this way, the time for which the circulation pump 21 rotates in the case of “waterless DRY” can be shortened, so that wear of the rotating shaft of the circulation pump 21 can be more reliably suppressed. As can be seen from FIG. 5, if the first determination time is short, the difference between the pump rotational speed of “with water” and the pump rotational speed of “without water WET” is difficult to occur. In the first control, the discrimination between “with water” and “without water WET” is not performed, and therefore the determination accuracy does not decrease even if the first determination time is short.

  As shown in FIG. 4, the behavior of the pump rotation speed with respect to the duty ratio is greatly different between “with water” and “without water WET” and “without water DRY”. However, it is difficult to make a large difference in the behavior of the pump speed between “with water” and “without water WET”. For this reason, there is a risk of erroneous determination when “with water” and “without water WET” are determined based on the number of revolutions of the pump. In particular, such misjudgment is likely to occur due to variations in the individual circulation pumps 21 or differences in the installation environment of the hot water storage type hot water heater 1. If the actual state is “waterless WET” and it is erroneously determined as “water present”, an abnormality that there is no water in the circulation pump 21 cannot be detected. On the other hand, if the actual state is “with water” and it is erroneously determined as “without water WET”, it is detected as an abnormality even though it is actually in a normal state. On the other hand, in the first control, it is possible to reliably prevent the erroneous determination as described above by determining that only “without water DRY” is abnormal without determining “with water” and “without water WET”. .

  In order to accurately discriminate between the pump speed of “with water” and “without water WET” and the pump speed of “without water DRY”, the drive signal for the circulation pump 21 in the first control (this embodiment) 1 is preferably a signal that increases the power supplied to the circulation pump 21 to some extent. The drive signal (duty ratio in the first embodiment) for the circulation pump 21 in the first control is more preferably a signal that maximizes the pump rotation speed. By doing as described above, the difference between the pump rotational speed of “with water” and “without water WET” and the pump rotational speed of “without water DRY” can be increased, so that both can be distinguished with higher accuracy.

  In the first control, the control unit 70 continuously operates the circulation pump 21 when the pump speed is lower than the first threshold value does not continue for the first determination time or longer. When the circulation pump 21 is continuously operated in the case of “waterless WET”, the water interposed between the pump rotary shaft and the bearing evaporates due to frictional heat between the pump rotary shaft and the bearing. Thus, a phenomenon occurs in which the state transitions from “waterless WET” to “waterless DRY”.

  FIG. 6 shows an example of a temporal change in the number of revolutions of the pump when the state of the circulation pump 21 of the hot water storage-type water heater 1 according to the first embodiment transitions from “waterless WET” to “waterless DRY”. FIG. As shown in FIG. 6, when a state transition from “waterless WET” to “waterless DRY” occurs, the pump rotation speed greatly changes before and after the state transition. In other words, the transition from “waterless WET” to “waterless DRY” greatly reduces the pump speed. Therefore, when the circulation pump 21 is continuously operated in the first control, there is a possibility that a transition from “waterless WET” to “waterless DRY” may be detected by detecting a decrease in the pump speed. I can judge. In the first embodiment, the control unit 70 performs the second control for determining whether the pump rotation speed is lower than the second threshold value when the circulating pump 21 is continuously operated in the first control. . The second threshold is a value that can determine whether or not there is a possibility of transition from “waterless WET” to “waterless DRY”. The second threshold is preferably a value equal to the first threshold or a value slightly larger than the first threshold. By setting the second threshold to such a value, it is possible to accurately determine whether or not there is a possibility of transition from “waterless WET” to “waterless DRY”.

  The control unit 70 may determine that the pump rotational speed is lower than the second threshold when the pump rotational speed is lower than the second threshold for a predetermined time or longer. This certain time is preferably shorter than the first determination time. When the controller 70 determines that the pump rotation speed is lower than the second threshold value in the second control, that is, when it is determined that there is a possibility of transition from “waterless WET” to “waterless DRY”, One control is performed again from the beginning. When the transition is actually made from “waterless WET” to “waterless DRY”, “waterless DRY” can be detected by performing the first control again from the beginning. When the “waterless DRY” is detected, the circulation pump 21 is stopped, so that the wear of the rotating shaft of the circulation pump 21 can be suppressed. As described above, the first control does not discriminate between “with water” and “without water WET”, but even when the actual state is “without water WET”, the second control performs “water” It is possible to transition from “no WET” to “no water DRY”. Thereafter, “no water DRY” can be detected by performing the first control again. For this reason, according to the first embodiment, it can be accurately determined that there is no water in the circulation pump 21.

  FIG. 7 is a flowchart of processing executed by the control unit 70 in the first control of the hot water storage type hot water heater 1 according to the first embodiment. When the air bleeding operation is started, the control unit 70 executes the process of the flowchart of FIG. First, in step S1, the control unit 70 performs control to fix the duty ratio of the drive signal for the circulation pump 21 to be constant. Next, the control unit 70 proceeds to step S2. In step S2, the control unit 70 compares the pump rotation speed detected by the rotation sensor 23 with the first threshold value. If the pump speed is greater than or equal to the first threshold value in step S2, the controller 70 proceeds to step S3. In step S3, the control unit 70 compares the elapsed time from the execution of step S1 with the second determination time. The second determination time is longer than the first determination time. In step S3, when the elapsed time since the execution of step S1 has not yet reached the second determination time, the control unit 70 returns to step S2. In step S3, when the elapsed time after executing step S1 is equal to or longer than the second determination time, the control unit 70 proceeds to step S5. In step S5, the control unit 70 determines that “there is water” or “no water”, or determines that there is no abnormality.

  When step S5 is reached, the control unit 70 operates the circulation pump 21 continuously as it is and performs the second control described above. That is, the control unit 70 determines whether or not the pump rotation speed is lower than the second threshold value, and when it is determined that the pump rotation speed is lower than the second threshold value, the first control is performed again from the beginning. When the first control is performed again from the beginning, the processing from step S1 may be started after the circulation pump 21 is once stopped and restarted, or the processing from step S1 is continued while the operation of the circulation pump 21 is continued. You may start.

  When the pump rotation speed is lower than the first threshold value in step S2, the control unit 70 proceeds to step S4. In step S4, the control unit 70 determines whether or not the state where the pump rotational speed is lower than the first threshold continues for the first determination time or longer. If the duration of the state where the pump speed is lower than the first threshold value has not yet reached the first determination time in step S4, the control unit 70 returns to step S2. If the pump speed is lower than the first threshold value in step S4, the controller 70 proceeds to step S6. In step S <b> 6, the control unit 70 determines that it is “no water DRY” or determines that there is an abnormality. When step S6 is reached, the control unit 70 stops the operation of the circulation pump 21.

  When it determines with it being "waterless DRY" and the driving | operation of the circulation pump 21 is stopped, the control part 70 may try 1st control again later (for example, after a fixed time passes). By doing in this way, after the operation of the circulation pump 21 is stopped, the hot water storage tank 10 is supplied with water, and when the inside of the circulation pump 21 is filled with water, the air bleeding operation can be automatically resumed.

  The control unit 70 may limit the number of times of trying the first control. Thereby, since it can prevent reliably that 1st control is implemented many times, abrasion of the rotating shaft of the circulation pump 21 can be suppressed more reliably. In addition, when the number of trials of the first control exceeds the limit number, the control unit 70 may notify this by, for example, displaying an error on the display unit of the remote controller 71. Thereby, it is possible to reliably notify the installation worker or the like that the hot water storage tank 10 is not supplied with water.

DESCRIPTION OF SYMBOLS 1 Hot water storage type water heater, 5 Hot water storage tank unit, 6 Heat pump unit, 7 Hot water supply pipe, 8 Hot water supply pipe, 10 Hot water storage tank, 11, 12 Hot water temperature sensor, 21 Circulation pump, 22 Use side heat exchanger, 23 Rotation sensor, 31 First three-way valve, 32 Second three-way valve, 33 Four-way valve, 34 Hot water solenoid valve, 35 Bath hot water flow path, 40 Tank lower pipe, 41a Heat pump inlet pipe, 41b Heat pump outlet pipe, 42a First tank upper pipe, 42b Second tank upper pipe, 43 Tank return pipe, 44a Heat source water inlet pipe, 44b Heat source water outlet pipe, 45 Bypass pipe, 46 Upper return pipe, 47 First circulation circuit, 48 Second circulation circuit, 51 Circuit, 52 bath circulation pump, 53 bath outlet temperature sensor, 54 hot water flow sensor, 55 hot water temperature sensor 56, return piping, 57 return piping, 58 flow switch, 61 compressor, 62 water-refrigerant heat exchanger, 63 expansion valve, 64 evaporator, 65 refrigerant circulation piping, 66 heat pump outlet temperature sensor, 70 controller 71 Remote control, 80 Bathtub adapter, 100 Bathtub

Claims (7)

A hot water storage tank,
A circulation pump for circulating hot water in a circulation circuit connecting the heating means for heating water and the hot water storage tank;
A rotational speed detection means for detecting the rotational speed of the circulation pump;
Control means for controlling the circulation pump;
With
The control means, as the first control, stops the circulation pump when the state in which the rotation speed of the circulation pump is lower than a first threshold value continues for a first determination time or more after the activation of the circulation pump. It determines that, otherwise performs control to operate continuously the circulation pump,
When the circulation pump is continuously operated even after the second determination time longer than the first determination time has elapsed from the start of the first control, the control means is configured so that the rotation speed of the circulation pump is Perform second control to determine whether it is lower than the second threshold,
The control means performs the first control again from the beginning when it is determined in the second control that the rotational speed of the circulation pump is lower than the second threshold,
The number of revolutions of the circulation pump in a state where the inside of the circulation pump is filled with water is higher than the first threshold value and the second threshold value,
There is no water inside the circulation pump, and the rotation speed of the circulation pump in a state where the space between the pump rotation shaft and the bearing is wet is higher than the first threshold value and the second threshold value,
The number of revolutions of the circulation pump in a state where there is no water inside the circulation pump and the space between the pump rotation shaft and the bearing is dry is lower than the first threshold value and the second threshold value. It becomes a hot water storage type water heater.   The said control means determines that there is no water inside the said circulation pump when the state where the rotation speed of the said circulation pump is lower than the said 1st threshold value by the said 1st control continues more than the said 1st determination time. 1. A hot-water storage water heater according to 1.   The first determination time is shorter than a time from when the circulation pump is activated to when the rotation speed of the circulation pump is stabilized when water is present inside the circulation pump in the first control. Item 3. A hot water storage type water heater according to Item 2.   In the first control, when the circulation pump is stopped because the rotation speed of the circulation pump is lower than the first threshold for the first determination time or longer in the first control, the first control is performed later. The hot water storage type hot water supply apparatus according to any one of claims 1 to 3, which is retried.   The hot water storage type hot water supply apparatus according to any one of claims 1 to 4, wherein the control means limits the number of trials of the first control.   The hot water storage type hot water supply apparatus according to any one of claims 1 to 5, further comprising notification means for notifying abnormality when the number of trials of the first control exceeds a limit number.   The hot water storage hot water supply according to any one of claims 1 to 6, wherein the control means uses a drive signal for the circulation pump in the first control as a signal that maximizes the number of revolutions of the circulation pump. Machine.

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