JP2022098720A - Hot water supply device - Google Patents

Abstract

To provide a hot water supply device capable of preventing blockage failure and blockage sign of a heat exchange portion.SOLUTION: In a hot water supply device including: a combustion portion divided into a plurality of combustion regions so as to change a region to be burned according to a necessary combustion amount; a fuel supply portion for adjusting a supply flow rate of a fuel to the combustion portion according to the necessary combustion amount; a combustion fan for supplying combustion air to the combustion portion; a heat exchange portion having a fin-and tube-type heat exchanger; a water supply portion for supplying hot water/water to the heat exchange portion; a hot water supply portion for supplying the hot water/water from the heat exchange portion; water supply temperature detection means for detecting a water supply temperature of the water supply portion; hot water supply temperature detection means for detecting a hot water supply temperature of the hot water supply portion; and a control portion for controlling a heating operation for supplying the hot water/water heated at the heat exchange portion by utilizing combustion heat of the combustion portion. The control portion includes a blockage state determination function for determining a blockage state of the heat exchange portion on the basis of heat efficiency of the heating operation under a predetermined determination condition.SELECTED DRAWING: Figure 4

Description

The present invention relates to a combustion-type hot water supply device, and is configured to detect a sign of a failure in heat exchange of a fin-and-tube heat exchanger that heats hot water using combustion heat. Regarding the device.

Conventionally, as in the case of the hot water supply device of Patent Document 1, a technique for detecting an initial symptom (predictor) of a failure by comparing the calculated energy efficiency with a reference value has been known. Since it is possible to take countermeasures such as parts replacement and replacement of the hot water supply device before the failure symptom worsens, it is possible to avoid the inconvenient state in which the hot water supply device cannot be used.

Japanese Unexamined Patent Publication No. 2019-163871

Even in a combustion type hot water supply device, as in Patent Document 1, the heat exchange unit that heats hot water using combustion heat by comparing the thermal efficiency of the heating operation that heats hot water using combustion heat with the standard value. It is being studied to detect blockage failures and signs of blockage. Since the thermal efficiency is adjusted according to the blockage state of the heat exchange section (soot, adhesion of oxidation products, decrease in heat exchange capacity due to adhesion of scale), it is possible to detect blockage failure and blockage sign of the heat exchange section. ..

The thermal efficiency is the ratio of the amount of heat used for heating the hot water to the amount of heat input, and can be calculated during the heating operation. However, the thermal efficiency fluctuates not only in the closed state of the heat exchange portion but also in the water entry temperature and the combustion amount. Immediately after the start of the heating operation, the amount of combustion fluctuates and is not stable because the temperature of the hot water is adjusted. Therefore, there is a risk of erroneously detecting a blockage failure or a sign of blockage in the heat exchange unit.

An object of the present invention is to provide a hot water supply device capable of preventing a blockage failure of a heat exchange unit and a false detection of a blockage sign.

The hot water supply device according to claim 1 has a combustion unit divided into a plurality of combustion regions so that the combustion region is changed according to the required combustion amount, and the required combustion amount of the fuel supply flow rate to the combustion unit. A fuel supply unit that adjusts according to the conditions, a combustion fan that supplies combustion air to the combustion unit, a heat exchange unit that has a fin-and-tube type heat exchanger, and a water supply unit that supplies hot water to the heat exchange unit. A hot water outlet that discharges hot water from the heat exchange unit, a water supply temperature detecting means that detects the water supply temperature of the water supply unit, a hot water temperature detecting means that detects the hot water outlet temperature of the hot water supply unit, and combustion of the combustion unit. In a hot water supply device provided with a control unit that controls a heating operation in which hot water heated by the heat exchange unit is discharged by using heat, the control unit determines the thermal efficiency of the heating operation under predetermined determination conditions. It is characterized by having a blockage state determination function for determining the blockage state of the heat exchange unit based on the above.

According to the above configuration, during the heating operation under predetermined determination conditions, the closed state of the heat exchange unit is determined based on the thermal efficiency of this heating operation. Therefore, by limiting the execution of the block state determination function to the heating operation that satisfies the determination condition, it is possible to exclude the factors that change the thermal efficiency. Therefore, since the blockage state of the heat exchange unit can be determined based on the thermal efficiency calculated under certain judgment conditions, it is possible to detect a blockage failure of the heat exchange unit or a false detection of a blockage sign due to a factor of fluctuation in the thermal efficiency. Can be prevented.

The hot water supply device according to claim 2 is characterized in that, in the invention of claim 1, the determination condition includes that the detection temperature of the water supply temperature detecting means is equal to or lower than the determination reference temperature.
According to the above configuration, it is possible to exclude the case where the water supply temperature before heating is higher than the determination reference temperature. Generally, the higher the water supply temperature, the smaller the required combustion amount and the lower the heat exchange capacity of the heat exchange section. It is possible to prevent erroneous detection of blockage failure and blockage sign caused by the blockage failure.

In the invention of claim 1 or 2, the hot water supply device of the third aspect of the invention is to burn in the combustion region equal to or larger than the determination reference number, and to change the fuel supply flow rate by the fuel supply unit. It is characterized in that the width is included in the judgment reference range.
According to the above configuration, it is possible to exclude the case where the number of combustion regions to be burned is less than the determination reference number and the amount of combustion is small, and the case where the amount of combustion greatly fluctuates according to the fluctuation of the fuel supply flow rate. When the amount of combustion is small, the heat exchange capacity of the heat exchange section decreases and the thermal efficiency fluctuates according to the fluctuation of the amount of combustion. It is possible to prevent false detection of failure and blockage signs.

In the invention of any one of claims 1 to 3, the hot water supply device according to the fourth aspect of the present invention is equipped with an immediate hot water circulation unit for returning the discharged hot water to the water supply unit and circulating the hot water, and the control unit. Is characterized in that the blockage state determination function is executed in the heating operation for heating the circulating hot water.
According to the above configuration, the blockage state determination function is executed even in the heating operation of the hot water circulated by the immediate hot water circulation unit. Even in this heating operation, the blockage state of the heat exchange section can be determined based on the thermal efficiency calculated under certain judgment conditions. False positives can be prevented. In particular, when the immediate hot water circulation unit is equipped and the heating operation with a small amount of combustion is performed very often because the water supply temperature is high, it is possible to effectively prevent the sign of blockage of the heat exchange unit and the false detection of blockage failure.

According to the hot water supply device of the present invention, it is possible to prevent a blockage failure and a false detection of a blockage sign due to a factor of fluctuation in thermal efficiency.

It is explanatory drawing of the combustion type hot water supply device which concerns on Example 1 of this invention. It is explanatory drawing of the structure of the control part of a water heater, and the communication path. It is a process explanatory drawing of the heating operation of a hot water supply device. It is a flowchart of the heat exchange part failure sign detection control which concerns on embodiment. It is explanatory drawing of the combustion type hot water supply apparatus equipped with the immediate hot water circulation unit which concerns on Example 2 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to examples.

The combustion type hot water supply device 1 is usually installed outdoors. As shown in FIG. 1, the hot water supply device 1 has a combustion unit 2, a heat exchange unit 3, a water supply unit 4, and a hot water outlet unit 5, and water is supplied in the heat exchange unit 3 by utilizing the combustion heat generated in the combustion unit 2. It is configured to perform a heating operation in which the hot water supplied from the unit 4 is heated and the hot water is discharged to the hot water discharge unit 5. A fuel supply unit 6 for supplying a fuel gas (natural gas or propane gas) is connected to the combustion unit 2.

In the vicinity of the combustion unit 2, combustion air is supplied to the combustion unit 2, and combustion gas, which is a medium of combustion heat generated by combustion, is sent to the heat exchange unit 3 and exhausted to the outside from the exhaust port 7. Is equipped with a combustion fan 8. The combustion unit 2 is divided into, for example, first to fourth combustion regions 2a to 2d as a plurality of combustion regions for mixing and burning the fuel gas supplied from the fuel supply unit 6 and the combustion air, and generates a required amount of heat. The area to be burned is changed according to the required amount of combustion.

The fuel supply unit 6 has first to fourth gas solenoid valves 6a to 6d corresponding to the first to fourth combustion regions 2a to 2d, and a fuel flow rate adjusting valve 6e for adjusting the fuel flow rate to be supplied to the combustion unit 2. .. The fuel supply unit 6 is configured to be able to adjust the fuel flow rate and individually switch the supply / stop of the fuel gas to the first to fourth combustion regions 2a to 2d.

The heat exchange unit 3 has a fin-and-tube type first heat exchanger 3a and a second heat exchanger 3b composed of a plurality of hot and cold water passages. The first heat exchanger 3a recovers the sensible heat of the high-temperature combustion gas immediately after combustion to heat the hot water. The second heat exchanger 3b recovers the latent heat of the combustion gas (combustion exhaust) whose sensible heat has been recovered and the temperature has dropped to heat the clean water.

In this second heat exchanger 3b, the water contained in the combustion gas is condensed to generate condensed water. This condensed water contains a component of combustion gas and is strongly acidic. Therefore, since it is inappropriate to drain the water as it is, it is introduced into a neutralization tank 9a containing, for example, calcium carbonate particles as a neutralizing agent, neutralized, and then drained. The combustion gas whose latent heat is recovered by the second heat exchanger 3b and whose temperature has dropped is exhausted to the outside through the exhaust port 7.

In the neutralization tank 9a, an introduction passage 9b that guides the condensed water that has fallen into the drain pan 3c arranged under the second heat exchanger 3b to the neutralization tank 9a, and the neutralized condensed water are supplied to the hot water supply device 1. A drainage passage 9c for draining to the outside is connected to form a neutralizing portion 9. The upper end of the neutralization tank 9a is equipped with a pair of electrode rods 9d as a water level detecting means for detecting the water level (predetermined water level) of the condensed water. A voltage is applied between a pair of electrode rods 9d, and a current flows between the pair of electrode rods 9d that have reached a predetermined water level and touched the condensed water, so that the predetermined water level is detected. Will be done.

The water supply unit 4 has a water supply passage 4a that supplies tap water supplied from the water supply source to the second heat exchanger 3b, and a water supply branch passage 4b that is branched from the water supply passage 4a and has a flow control valve 10. The hot water heated by the second heat exchanger 3b is introduced into the first heat exchanger 3a and heated to a higher temperature. The hot water heated by the first heat exchanger 3a is supplied to the hot water outlet passage 5a. In the hot water outlet portion 5 formed by connecting the water supply branch passage 4b to the hot water outlet passage 5a, the heated hot water and tap water are mixed to adjust the temperature, and hot water is supplied to, for example, a hot water tap 11a at the hot water supply destination of the hot water supply passage 11. To.

The first combustion region 2a of the combustion unit 2 is an ignition region that ignites when the heating operation is started and first burns. An ignition device 14 that generates sparks by electric discharge and a first frame rod 15a for detecting a flame in the first combustion region 2a for ignition confirmation are arranged at positions corresponding to the first combustion region 2a. There is.

The second combustion region 2b adjacent to the first combustion region 2a is a fire transfer region in which the combustion region is first expanded from the first combustion region 2a in order to increase the amount of combustion and increase the generation of combustion heat. .. A second frame rod 15b for detecting a flame in the second combustion region 2b is arranged at a position corresponding to the second combustion region 2b. The amount of combustion can be increased by expanding the combustion region to the third and fourth combustion regions 2c and 2d. In addition, in order to detect the flames in the third and fourth combustion regions 2c and 2d, the frame rods corresponding to the third and fourth combustion regions 2c and 2d may be arranged.

The water supply passage 4a is provided with a water supply flow rate sensor 4c for detecting the water supply flow rate of tap water supplied to the heat exchange unit 3 and a water supply temperature sensor 4d (water supply temperature detecting means) for detecting the water supply temperature. A hot water temperature sensor 5b (hot water temperature detecting means) for detecting the hot water temperature of the hot water heated by the heat exchange unit 3 is provided in the hot water discharge passage 5a. A hot water supply temperature sensor 5c for detecting the hot water supply temperature of hot water mixed with tap water and whose temperature is adjusted is arranged on the downstream side of the connection portion of the hot water supply passage 5a with the water supply branch passage 4b. ..

The hot water supply device 1 includes a control unit 16 that controls a heating operation in order to supply hot water at a hot water supply set temperature based on a water supply flow rate, a water supply temperature, and a hot water outlet temperature. The hot water supply set temperature is set by the operation of the operation terminal 17 connected to the control unit 16. In the heating operation, the control unit 16 calculates a required combustion amount (required heat amount) based on, for example, a hot water supply set temperature, a water supply flow rate, and a water supply temperature. Then, the control unit 16 sets the combustion region to be burned by the combustion unit 2, the target rotation speed of the combustion fan 8, and the fuel flow rate of the fuel supply unit 6 in order to generate the required heat amount. Further, the control unit 16 adjusts the opening degree of the flow rate adjusting valve 10 so that the hot water supply temperature approaches the hot water supply set temperature, and adjusts the mixing ratio of the clean water and the heated hot water.

As shown in FIG. 2, the control unit 16 includes a calculation unit 16a for executing various control programs, a storage unit 16b for storing various control programs, control parameters, and the like, and a communication unit 16c. The calculation unit 16a controls the valves of the flow rate adjusting valve 10 and the fuel supply unit 6 and the combustion fan 8 via the communication unit 16c that communicates with the built-in device of the hot water supply device 1 and the operation terminal 17, and also controls the combustion fan 8 and the water supply temperature sensor 4d. The detection signal of the sensors such as, etc., and the operation content of the operation terminal 17 are received.

The operation terminal 17 is connected to an external communication network 19 (Internet) via, for example, a communication gateway 18 having a home network construction function. In this communication network 19, management installed by a service shop or a manufacturer that constructs and maintains the hot water supply device 1 in order to manage information on the hot water supply device and other devices currently installed including the hot water supply device 1. The server 20 is connected. As a result, the control unit 16 can communicate with the management server 20. The communication unit 16c or the operation terminal 17 may be directly connected to the communication network 19.

When the water supply flow rate detected by the water supply flow rate sensor 4c becomes equal to or higher than a predetermined minimum flow rate due to the start of use of the hot water supply, the heating operation is started. As shown in FIG. 3, the heating operation is divided into a pre-purge step, an ignition step, a combustion step, and a post-purge step. In the pre-purge step, the target rotation speed of the combustion fan 8 is set to the scavenging rotation speed (for example, 3000 rpm), and the combustion fan 8 is driven by the scavenging rotation speed for a predetermined pre-purge time (for example, 5 seconds). As a result, the air staying in the combustion unit 2 and the heat exchange unit 3 is exhausted from the exhaust port 7, and the rotation speed of the stopped combustion fan 8 increases to about the scavenging rotation speed.

Next, in the ignition process, the first gas electromagnetic valve 12a corresponding to the first combustion region 2a (ignition region) is opened, the target rotation speed is set to the ignition rotation speed (for example, 2500 rpm), and the combustion fan 8 is operated. It is driven by the ignition speed. Then, the ignition device 14 is driven to ignite the first combustion region 2a. When the flame in the first combustion region 2a is detected (ignition confirmed) by the first frame rod 15a, the process proceeds to the combustion process.

Next, in the combustion step, the combustion region to be burned by the combustion unit 2, the target rotation speed of the combustion fan 8, and the fuel flow rate of the fuel supply unit 6 are set so that the calculated required heat amount can be supplied. Then, the combustion fan 8 is driven at the target rotation speed, the fuel gas electromagnetic valve corresponding to the combustion region to be burned is opened, fuel is supplied at the set fuel flow rate, the required heat amount is generated, and the hot water supply set temperature is reached. Hot water is supplied.

When the water supply flow rate becomes less than the predetermined minimum flow rate due to the end of use of the hot water supply, the process shifts to the post-purge process. In the post-purge step, all open gas electromagnetic valves are closed, combustion of the combustion unit 2 is stopped, the target rotation speed is set to the scavenging rotation speed, and the combustion fan 8 has the post-purge time (for example, 10) at the scavenging rotation speed. Seconds) Driven. As a result, the combustion gas is exhausted so as not to remain in the combustion unit 2 and the heat exchange unit 3. Finally, the combustion fan 8 is stopped, and the heating operation is completed.

When installing the hot water supply device 1, a trial run is performed to confirm that the hot water supply device 1 operates normally. The control unit 16 stores the heating operation data at the time of the test run in the storage area of the storage unit 16b or the management server 20 as the initial data at the time of installation.

In the heating operation, for example, soot and oxidation products gradually adhere to the outside (combustion gas passage) of the heat exchange unit 3, especially the first heat exchanger 3a, and the inside (hot water passage) is contained in hot water. The minerals are gradually attached. Therefore, the heat exchange between the combustion gas and the hot water is hindered, and the thermal efficiency of the heating operation gradually decreases.

For example, when the thermal efficiency drops to a preset blockage failure reference thermal efficiency (for example, 50%), it is determined that a blockage failure of the heat exchange unit 3 has occurred and combustion is prohibited. Notify, for example, a service shop via 20. The user or service shop who knows the occurrence of this failure arranges inspection and repair.

It is not preferable for the user of the hot water supply device 1 because the hot water supply device 1 suddenly becomes unusable due to the prohibition of combustion. Therefore, when the control unit 16 detects a sign of a blockage failure of the heat exchange unit 3 before determining that the blockage failure of the heat exchange unit 3, the sign of the blockage failure of the heat exchange unit 3 is detected via the management server 20. Notify the service shop that there is something and urge them to check it. The determination of the sign detection of the blockage failure of the heat exchange unit 3 is performed based on the thermal efficiency of the heating operation under a certain preset determination condition.

In order to detect a blockage failure or a sign of blockage of the heat exchange unit 3, it is required to calculate an accurate thermal efficiency that reflects the state of the heat exchange unit 3 so as to prevent erroneous detection. Therefore, the judgment conditions are that the fluctuation range of the fuel flow rate is within the judgment reference range, the number of combustion regions during combustion of the combustion unit 2 is equal to or more than the judgment reference number, and the water supply temperature before heating is the judgment reference temperature. It includes the following: The blockage state determination function for detecting the blockage failure and the blockage sign of the heat exchange unit 3 will be described with reference to the flowchart of the heat exchange section blockage failure sign detection control of FIG. 4 by the control unit 16. Si (i = 1, 2, ...) In the figure represents a step.

When the heating operation is started, the air accumulated in the pre-purge step is exhausted to introduce fresh air, and in the next ignition step, the combustion unit 2 is ignited by the ignition device 14, and then the combustion step is started. At the same time, the heat exchange unit blockage failure sign detection control is started.

In S1, from the start of the combustion process until a predetermined time elapses, the process proceeds to S2 while waiting while acquiring data of various flow rates and various temperatures. Immediately after the start of the heating operation, the combustion amount fluctuates in order to adjust the hot water temperature, so this is a step of waiting until the combustion amount stabilizes. The predetermined time is set in advance based on an experiment or the like, and is, for example, 20 seconds. The data to be acquired includes, for example, a water supply flow rate, a fuel flow rate, a water supply temperature, and a hot water outlet temperature, and is stored in the storage unit 16b.

Next, in S2, data for calculating the thermal efficiency within the thermal efficiency calculation period is acquired, and the process proceeds to S3. The data acquired at this time are, for example, the water supply flow rate, the fuel flow rate, the water supply temperature, the hot water temperature, the fluctuation range of the fuel flow rate, and the number of combustion regions during combustion as the thermal efficiency calculation period for the last 5 seconds of the predetermined time of S1.

In S3, it is determined whether or not the fluctuation range of the fuel flow rate is within the determination reference range. Since it is necessary for the combustion amount to be stable for accurate thermal efficiency calculation, this is a step for determining whether or not the fuel flow rate is stable. If the determination in S3 is No, the heating operation does not satisfy the determination condition, and the process returns to S1. If the determination of S3 is Yes, the process proceeds to S4.

In S4, it is determined whether or not the number of combustion regions during combustion of the combustion unit 2 is equal to or greater than the determination reference number. The number of combustion regions during combustion decreases as the amount of combustion decreases, and the thermal efficiency tends to decrease when the number of combustion regions during combustion is small. Therefore, when the number of combustion regions during combustion is small (for example, 2 or less). If) is a step to exclude. If the determination in S4 is No, the heating operation does not satisfy the determination condition, and the process returns to S1. If the determination in S4 is Yes, the process proceeds to S5.

In S5, it is determined whether or not the detection temperature (water supply temperature) of the water supply temperature sensor 4d is equal to or lower than the determination reference temperature. As the water supply temperature is higher, the temperature to be raised (temperature difference before and after heating) tends to be smaller and the thermal efficiency tends to decrease. Therefore, in order to exclude the case where the water supply temperature is higher than the judgment reference temperature (for example, 25 ° C.). It's a step. When the determination in S5 is No, it is a heating operation that does not satisfy the determination condition, and it is unlikely that the water supply temperature will fluctuate during this heating operation. Therefore, the heat exchange unit blockage failure sign detection control is terminated without determining the detection of the blockage failure or blockage sign of the heat exchange unit 3. If the determination in S5 is Yes, the process proceeds to S6.

In S6, the thermal efficiency is calculated based on the hot water temperature, the water supply temperature, the water supply flow rate, and the fuel flow rate, and the process proceeds to S7. Thermal efficiency is calculated by the ratio of the amount of heat used for heating calculated by multiplying the difference temperature (increased temperature) between the hot water outlet temperature and the supply water temperature by the supply water flow rate to the input heat amount calculated based on the fuel flow rate. Will be done. For example, in the hot water supply device 1 having the first and second heat exchangers 3a and 3b as the heat exchange unit 3, the thermal efficiency at the time of installation of the hot water supply device 1 is about 95%.

In S7, it is determined whether or not the thermal efficiency calculated in S6 is less than the blockage sign reference thermal efficiency. The blockage sign reference thermal efficiency is set to a higher thermal efficiency (for example, 60%) than the blockage failure reference thermal efficiency that causes a blockage failure of the heat exchange unit 3, and countermeasures can be taken before the blockage failure of the heat exchange section 3 occurs. I am trying to do it. If the determination in S7 is No, it is assumed that the blockage sign is not detected, and the heat exchange unit blockage failure sign detection control is terminated while the heating operation is continued. If the determination in S7 is Yes, the process proceeds to S8.

In S8, it is determined whether or not the thermal efficiency calculated in S6 is less than the blockage failure reference thermal efficiency. If the determination in S8 is Yes, the process proceeds to S9, and the notification that the blockage failure of the heat exchange unit 3 is detected in S9 is notified, the heating operation is terminated, and the heat exchange section blockage failure sign detection control is terminated. On the other hand, if the determination in S8 is No, the process proceeds to S10, the notification that the blockage sign of the heat exchange unit 3 is detected in S10 is notified, and the heat exchange unit blockage failure sign detection control is terminated while the heating operation is continued. ..

The detection of the blockage failure and the detection of the blockage sign are notified to, for example, a service shop via the management server 20, and prompt for inspection, repair, and the like. If the heating operation is completed before the heat exchange unit blockage failure sign detection control is completed, the heat exchange unit blockage failure sign detection control is terminated at that time.

The water heater 1 which is a partial modification of the first embodiment will be described. The same parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.
As shown in FIG. 5, the hot water supply device 1 is equipped with an immediate hot water circulation unit 21 so that hot water is supplied as soon as the hot water tap 11a is opened. The immediate hot water circulation unit 21 includes a circulation pump 22, a check valve 23, an air separator 24, and an expansion tank 25. The circulation pump 22 circulates the hot water by supplying (returning) the hot water of the hot water supply passage 11 connected to the hot water outlet passage 5a to the water supply passage 4a of the water supply unit 4. The air separator 24 separates the air mixed in the circulating hot water. The expansion tank 25 absorbs the thermal expansion of the circulating hot water.

For example, when hot water is not being supplied, the control unit 16 drives the circulation pump 22 to circulate hot water between the hot water supply device 1 and the immediate hot water circulation unit 21, so that the water supply flow rate becomes equal to or higher than a predetermined minimum flow rate. The heating operation is started. This circulating hot water is heated by the heat exchange unit 3 using the combustion heat of the combustion unit 2 by the heating operation and supplied to the hot water supply passage 11, and the hot water in the hot water supply passage 11 is maintained at a constant temperature.

Also in the heating operation for heating the circulating hot water, the blockage state determination function is executed as in the case of supplying hot water in the first embodiment. For example, the operation of the immediate hot water circulation unit 21 is turned off when there is no opportunity to supply hot water due to absenteeism for a long time due to travel, etc., and the hot water is circulated when the operation of the immediate hot water circulation unit 21 is turned on after returning home. The heating operation is performed. In this case, since the temperature of the hot water at the start of circulation is not high, it is possible to detect the blockage sign and the blockage failure of the heat exchange unit 3 based on the thermal efficiency of the heating operation, as in the case of hot water supply from the hot water tap 11a. ..

On the other hand, when the hot water circulation unit 21 continuously or intermittently circulates hot water and the hot water supply device 1 is performing the heating operation, the temperature of the hot water in the water supply passage 4a (water supply temperature) is high. The amount of combustion is reduced and the thermal efficiency is reduced. Since the actual blockage state of the heat exchange unit 3 is not accurately reflected in this thermal efficiency, there is a risk of erroneously detecting a blockage sign or a blockage failure of the heat exchange unit 3.

However, as a predetermined determination condition, it is based on the thermal efficiency of the heating operation when the determination criteria are satisfied for the fuel flow rate fluctuation range of S3 in FIG. 4, the number of combustion regions during combustion of S4, and the water supply temperature of S5, respectively. Therefore, since the blockage sign and the blockage failure are detected, erroneous detection can be avoided. In particular, when the immediate hot water circulation unit 21 is equipped and the amount of combustion is small due to the high water supply temperature and the number of executions of heating operation is very large, it is effective to detect blockage signs and blockage failures of the heat exchange unit 3 based on thermal efficiency. Can be prevented.

The operation and effect of the hot water supply device 1 will be described.
The control unit 16 of the hot water supply device 1 determines the blocked state of the heat exchange unit 3 based on the thermal efficiency of the heating operation during the heating operation under predetermined determination conditions. Therefore, by limiting the execution of the block state determination function to the heating operation that satisfies the determination condition, it is possible to exclude the factors that change the thermal efficiency. Therefore, since the blockage state of the heat exchange unit 3 can be determined based on the thermal efficiency calculated under certain determination conditions, the heat exchange unit 3 is blocked due to a variable factor of the thermal efficiency, and the blockage sign is erroneous. Detection can be prevented.

Generally, the higher the water supply temperature, the smaller the required combustion amount and the lower the heat exchange capacity of the heat exchange unit 3. By excluding the case where the water supply temperature before heating is higher than the judgment reference temperature, it is possible to exclude the factors that change the thermal efficiency due to the water supply temperature. Detection can be prevented.

Generally, when the amount of combustion is small, the heat exchange capacity of the heat exchange unit 3 decreases, and the thermal efficiency fluctuates according to the fluctuation of the amount of combustion. By excluding the case where the number of combustion regions to be burned is less than the judgment standard number and the case where the combustion amount fluctuates greatly according to the fluctuation of the fuel supply flow rate, the factors that fluctuate the thermal efficiency can be excluded. Therefore, it is possible to prevent a blockage failure or a false detection of a blockage sign due to a factor of fluctuation in thermal efficiency.

The control unit 16 also executes the blockage state determination function in the heating operation of hot water circulated by the immediate hot water circulation unit 21. Even in this heating operation, the blocked state of the heat exchange unit 3 can be determined based on the thermal efficiency calculated under certain determination conditions, so that the heat exchange unit 3 is blocked or blocked due to a factor that fluctuates the thermal efficiency. It is possible to prevent false detection of signs. In particular, when the immediate hot water circulation unit 21 is equipped and the heating operation with a small amount of combustion is performed very often due to the high water supply temperature, it is possible to effectively prevent the blockage sign and the false detection of the blockage failure of the heat exchange unit 3. can. In addition, it is possible to prevent the transmission of false detection information of a failure sign to the management server 20 and reduce the communication amount.

Based on the initial data, the blockage failure reference thermal efficiency is set as a predetermined ratio of the initial data during the trial run (for example, 50% of the initial data), and the blockage sign reference thermal efficiency is set as the predetermined ratio of the initial data during the trial run (for example, 60% of the initial data). The heat exchange unit 3 may be detected as a blockage failure or a blockage sign. In addition, a person skilled in the art can carry out the embodiment in a form in which various modifications are added to the above embodiment without departing from the spirit of the present invention, and the present invention includes such modified embodiments.

1: Hot water supply device 2: Combustion unit 2a: First combustion region (ignition region)
2b: Second combustion region (fire transfer region)
2c: 3rd combustion region 2d: 4th combustion region 3: Heat exchange unit 3a: 1st heat exchanger 3b: 2nd heat exchanger 3c: Drain pan 4: Water supply unit 4a: Water supply passage 4b: Water supply branch passage 4c: Water supply Flow sensor 4d: Water supply temperature sensor (water supply temperature detecting means)
5: Hot water outlet 5a: Hot water passage 5b: Hot water temperature sensor (hot water temperature detecting means)
5c: Hot water supply temperature sensor 6: Fuel supply unit 6a to 6d: 1st to 4th gas electromagnetic valves 6e: Fuel flow rate adjusting valve 7: Exhaust port 8: Combustion fan 9: Neutralization unit 9a: Neutralization tank 9b: Introduction passage 9c: Drainage passage 10: Flow rate adjusting valve 11: Hot water supply passage 11a: Hot water tap 14: Ignition device 15a: First frame rod 15b: Second frame rod 16: Control unit 16a: Calculation unit 16b: Storage unit 16c: Communication unit 17 : Operation terminal 18: Communication gateway 19: Communication network 20: Management server 21: Immediate hot water circulation unit 22: Circulation pump 23: Check valve 24: Air separator 25: Expansion tank

Claims (4)

A combustion unit divided into a plurality of combustion regions so that the combustion region is changed according to the required combustion amount, and a fuel supply unit that adjusts the fuel supply flow rate to the combustion unit according to the required combustion amount. A combustion fan that supplies combustion air to the combustion unit, a heat exchange unit having a fin-and-tube type heat exchanger, a water supply unit that supplies hot water to the heat exchange unit, and hot water discharged from the heat exchange unit. The hot water supply unit, the water supply temperature detecting means for detecting the water supply temperature of the water supply unit, the hot water discharge temperature detecting means for detecting the hot water discharge temperature of the hot water supply unit, and the heat exchange unit using the combustion heat of the combustion unit. In a hot water supply device equipped with a control unit that controls the heating operation to discharge heated hot water.
The control unit is provided with a blockage state determination function for determining a blockage state of the heat exchange unit based on the thermal efficiency of the heating operation under predetermined determination conditions. The hot water supply device according to claim 1, wherein the determination condition includes that the detection temperature of the water supply temperature detecting means is equal to or lower than the determination reference temperature. The claim is characterized in that the determination condition includes combustion in the combustion region equal to or larger than the determination reference number, and the fluctuation range of the fuel supply flow rate by the fuel supply unit is within the determination reference range. The hot water supply device according to 1 or 2. An immediate hot water circulation unit for returning the discharged hot water to the water supply unit and circulating it is provided, and the control unit executes the blockage state determination function in the heating operation for heating the circulating hot water. The hot water supply device according to any one of claims 1 to 3.

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