JP7535693B2 - Hot water supply equipment - Google Patents

Description

The present invention relates to a combustion-type hot water supply system equipped with a heat exchanger that recovers the latent heat of combustion gas and a neutralization tank that neutralizes the acidic condensed water generated in the heat exchanger, and in particular to a hot water supply system configured to detect blockages that prevent water from being drained from the neutralization tank.

Conventionally, there has been known a technology that includes a heat exchanger that recovers the latent heat of combustion gas and a neutralization tank that neutralizes the acidic condensed water generated in the heat exchanger, such as the water heater in Patent Document 1, and detects when water can no longer be drained from the neutralization tank by the temperature detected by an exhaust thermistor. Meanwhile, a technology that detects the water level of the condensed water in the neutralization tank by the current flowing between a pair of electrodes is also widely known. In either case, by detecting the water level before the condensed water overflows from the neutralization tank and affects other parts of the water heater, it is possible to detect when water can no longer be drained through the drain passage connected to the neutralization tank.

JP 2010-249438 A

When a neutralization tank equipped with a pair of electrodes as a water level detection means detects a certain level of condensed water for a certain period of time, it is determined that a blockage has occurred, and the water heater is prohibited from heating (safety operation). Once a blockage occurs, the water heater cannot be used, which is an inconvenient situation, until maintenance such as replacing the neutralization tank is completed.

However, there are cases where temporary blockage occurs, for example, when a biofilm formed by the proliferation of microorganisms in the neutralization tank breaks down as the water level rises in the tank and flows out together with the condensed water. On the other hand, there are cases where the drainage passage of the neutralization tank is not completely blocked, for example, when a foreign object enters the drainage passage of the neutralization tank, and while the balance between the amount of condensed water generated and the amount of water discharged from the neutralization tank is maintained when the amount of combustion is small, the amount of condensed water generated exceeds the amount of water discharged when the amount of combustion is increased. In these cases, even if it is not determined that a blockage has occurred, there is a risk that it will occur in the near future, so it is being considered to detect signs of blockage before heating operation is prohibited by safety operation.

The object of the present invention is to provide a hot water supply device that can detect signs of blockage in the neutralization tank or drain passage.

The hot water supply device of the invention of claim 1 is a hot water supply device including a combustion section, a fuel supply section that supplies fuel to the combustion section, a combustion fan that supplies combustion air to the combustion section, a heat exchange section having a heat exchanger that recovers latent heat from the combustion exhaust, a neutralization section that neutralizes condensed water generated in the heat exchange section, a water supply section, a hot water outlet section, and a control section that controls a heating operation that uses the combustion heat of the combustion section to supply hot water heated in the heat exchange section, and the neutralization section includes a neutralization tank that contains a neutralizing agent, an introduction passage that introduces condensed water to the neutralization tank, and a drain passage that drains the neutralized condensed water to the outside. In a hot water supply device having a drain passage and a water level detection means for detecting the water level of condensed water in the neutralization tank, and the control unit performs a safety operation of prohibiting the heating operation by determining that a blockage has occurred in the neutralization tank or the drain passage when the water level detection means detects a predetermined water level continuously for a reference time or more, the control unit is characterized by having a blockage sign detection function that determines that a sign of blockage in the neutralization tank or the drain passage has been detected when the number of times that the water level detection means detects the predetermined water level for a period of time less than the reference time exceeds a preset reference number.

According to the above configuration, if the detection of the specified water level continues for a reference time or more, a safety operation is performed, and if the number of detections of the specified water level within the reference time reaches or exceeds the reference number, it is determined that a sign of blockage in the neutralization tank or the drain passage has been detected. Therefore, since it is determined that a sign of blockage in the neutralization tank or the drain passage has been detected when a temporary blockage is detected the reference number of times, it is possible to detect a sign of blockage before heating operation is prohibited by the safety operation.

The hot water supply device of the invention of claim 2 is a hot water supply device including a combustion section, a fuel supply section that supplies fuel to the combustion section, a combustion fan that supplies combustion air to the combustion section, a heat exchange section having a heat exchanger that recovers latent heat from the combustion exhaust, a neutralization section that neutralizes condensed water generated in the heat exchange section, a water supply section, a hot water discharge section, and a control section that controls a heating operation that uses the combustion heat of the combustion section to discharge hot water heated in the heat exchange section, and the neutralization section includes a neutralization tank that contains a neutralizing agent, an introduction passage that introduces condensed water to the neutralization tank, a drainage passage that drains the neutralized condensed water to the outside, and a water level detection section that detects the water level of the condensed water in the neutralization tank. In a hot water supply device having a means, and the control unit performs a safety operation of prohibiting the heating operation by judging that a blockage has occurred in the neutralization tank or the drain passage when the water level detection means detects a predetermined water level continuously for a reference time or more, the control unit is characterized by having a blockage sign detection function that, when the water level detection means detects the predetermined water level, reduces the heating capacity until the amount of condensed water generated is reduced and the predetermined water level is no longer detected, and judges that a sign of blockage in the neutralization tank or the drain passage has been detected when the heating capacity at the time when the predetermined water level is no longer detected is below a preset reference capacity.

According to the above configuration, when the specified water level is detected, the heating capacity is reduced to reduce the amount of condensed water generated, thereby attempting to make the specified water level undetectable. Then, if the heating capacity when the specified water level is no longer detected is below the standard capacity, it is determined that a sign of blockage of the neutralization tank or drainage passage has been detected. On the other hand, if the detection of the specified water level continues for more than the standard time, a safety operation is performed. Therefore, since it is determined that a sign of blockage of the neutralization tank or drainage passage has been detected based on the heating capacity even if the tank is not completely blocked, it is possible to detect a sign of blockage of the neutralization tank or drainage passage before heating operation is prohibited by the safety operation.

The water heating apparatus of the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the control unit issues an alert to encourage inspection of the neutralization unit when it determines that the blockage prediction detection function has detected a sign of blockage in the neutralization tank or the drainage passage.
According to the above configuration, before the heating operation is prohibited by the safety operation, a warning is issued to prompt the inspection of the neutralization unit by detecting a sign of blockage in the neutralization tank or the drain passage. Therefore, by inspecting and replacing the neutralization unit before the safety operation based on this warning, it is possible to avoid an inconvenient situation in which the hot water supply device suddenly becomes unusable due to the safety operation.

The hot water supply device of the present invention can detect signs of blockage in the neutralization tank or drainage passage.

1 is an explanatory diagram of a combustion type hot water supply device according to the present invention. 2 is an explanatory diagram of a configuration and communication paths of a control unit of the water heating apparatus; FIG. FIG. 4 is a process explanatory diagram of the heating operation of the water heater. 4 is a flowchart of a failure sign detection control according to the first embodiment. 10 is a flowchart of a failure sign detection control according to a second embodiment.

The following describes the form for implementing the present invention based on examples.

The combustion-type hot water heater 1 is usually installed outdoors. As shown in FIG. 1, the hot water heater 1 has a combustion section 2, a heat exchange section 3, a water supply section 4, and a hot water outlet section 5, and is configured to perform a heating operation in which the heat of combustion generated in the combustion section 2 is used to heat clean water supplied from the water supply section 4 in the heat exchange section 3, and the clean water is then discharged to the hot water outlet section 5. A fuel supply section 6 for supplying fuel gas (natural gas or propane gas) is connected to the combustion section 2.

A combustion fan 8 is installed near the combustion section 2 to supply combustion air to the combustion section 2 and to send the combustion gas, which is the medium for the combustion heat generated by combustion, to the heat exchange section 3 and exhaust it to the outside from the exhaust port 7. The combustion section 2 is divided into multiple combustion areas, for example, first to fourth combustion areas 2a to 2d, where the fuel gas supplied from the fuel supply section 6 is mixed with the combustion air and burned, and the area in which combustion is performed is changed depending on the amount of combustion required to generate the required amount of heat.

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 adjustment valve 6e that adjusts the fuel flow rate supplied to the combustion unit 2. The fuel supply unit 6 adjusts the fuel flow rate and is configured to be able to individually switch between supplying and stopping fuel gas to the first to fourth combustion regions 2a to 2d.

The heat exchange section 3 has a first fin-and-tube heat exchanger 3a and a second heat exchanger 3b consisting of multiple 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 and cold water. The second heat exchanger 3b recovers the latent heat of the combustion gas (combustion exhaust) whose temperature has been reduced by recovering the sensible heat to heat the drinking water.

In this second heat exchanger 3b, the moisture contained in the combustion gas condenses to produce condensed water. This condensed water contains components of the combustion gas and is highly acidic. Therefore, it is inappropriate to drain it as is, so it is introduced into a neutralization tank 9a that contains, for example, calcium carbonate granules as a neutralizing agent, and is neutralized before being drained. The combustion gas, whose temperature has been reduced by recovering latent heat in the second heat exchanger 3b, is exhausted to the outside through the exhaust port 7.

The neutralization tank 9a is connected to an inlet passage 9b that guides the condensed water that has fallen into the drain pan 3c disposed below the second heat exchanger 3b into the neutralization tank 9a, and a drain passage 9c that drains the neutralized condensed water to the outside of the hot water supply device 1, forming a neutralization section 9. The upper end of the neutralization tank 9a is equipped with a pair of electrodes 9d as a water level detection means for detecting the water level of the condensed water (predetermined water level). A voltage is applied between the pair of electrodes 9d, and when the water level reaches the predetermined level, a current flows between the pair of electrodes 9d through the condensed water, detecting the predetermined water level.

The water supply section 4 has a water supply passage 4a that supplies clean water supplied from a clean water source to the second heat exchanger 3b, and a water supply branch passage 4b that branches off from the water supply passage 4a and is equipped with a flow rate adjustment valve 10. The hot water heated in the second heat exchanger 3b is introduced into the first heat exchanger 3a and is further heated to a high temperature. The hot water heated in the first heat exchanger 3a is supplied to the hot water outlet passage 5a. In the hot water outlet section 5 formed by connecting the water supply branch passage 4b to the hot water outlet passage 5a, the heated hot water and clean water are mixed and the temperature is adjusted, and the hot water is supplied to the hot water supply destination, for example, the hot water tap 11.

The first combustion area 2a of the combustion section 2 is the area that is ignited and burned first when the heating operation starts. In the position corresponding to this first combustion area 2a, an ignition device 14 that generates sparks by discharge and a first flame rod 15a for detecting the flame in the first combustion area 2a to confirm ignition are arranged.

The second combustion area 2b adjacent to the first combustion area 2a is a flame-transfer area that first expands the combustion area from the first combustion area 2a in order to increase the amount of combustion and increase the generation of combustion heat. A second flame rod 15b for detecting the flame in the second combustion area 2b is disposed in a position corresponding to this second combustion area 2b. The amount of combustion can be increased by expanding the combustion area to the third and fourth combustion areas 2c and 2d. Note that flame rods corresponding to the third and fourth combustion areas 2c and 2d may be disposed in order to detect the flames in the third and fourth combustion areas 2c and 2d.

In the water supply passage 4a, there is disposed a water supply flow rate sensor 4c for detecting the water supply flow rate of clean water supplied to the heat exchange section 3, and a water supply temperature sensor 4d for detecting the water supply temperature. In the hot water outlet passage 5a, there is disposed an outlet water temperature sensor 5b for detecting the outlet temperature of the hot water heated in the heat exchange section 3. Downstream of the connection of the hot water outlet passage 5a with the water supply branch passage 4b, there is disposed a hot water supply temperature sensor 5c for detecting the hot water supply temperature of the hot water that has been mixed with the clean water and has had its temperature adjusted.

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

As shown in FIG. 2, the control unit 16 has a calculation unit 16a that executes various control programs, a memory unit 16b that stores various control programs, control parameters, etc., and a communication unit 16c. The calculation unit 16a controls the flow rate control valve 10, the valves of the fuel supply unit 6, and the combustion fan 8 via the communication unit 16c, which communicates with the built-in devices of the water heater 1 and the operation terminal 17, and receives detection signals from sensors such as the water supply temperature sensor 4d, and the operation details of the operation terminal 17.

The operation terminal 17 is connected to an external communication network 19 (Internet) via a communication gateway 18 equipped with a home network construction function, for example. A management server 20 installed by a service shop or manufacturer that installs and maintains the water heating apparatus 1 is connected to this communication network 19 in order to manage information about currently installed water heating apparatuses, including the water heating apparatus 1, and other equipment. This enables the control unit 16 to communicate with the management server 20. Note that 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 reaches or exceeds a predetermined minimum flow rate due to the start of hot water supply use, heating operation is started. As shown in FIG. 3, heating operation is divided into a pre-purge process, an ignition process, a combustion process, and a post-purge process. In the pre-purge process, the target rotation speed of the combustion fan 8 is set to the scavenging rotation speed (e.g., 3000 rpm), and the combustion fan 8 is driven at the scavenging rotation speed for a predetermined pre-purge time (e.g., 5 seconds). As a result, air remaining in the combustion section 2 and the heat exchange section 3 is exhausted from the exhaust port 7, and the rotation speed of the combustion fan 8, which was stopped, increases to about the scavenging rotation speed.

Then, the process moves to the ignition process, in which the first gas solenoid valve 12a corresponding to the first combustion area 2a (ignition area) is opened, the target rotation speed is set to the ignition rotation speed (e.g., 2500 rpm), and the combustion fan 8 is driven at the ignition rotation speed. Then, the ignition device 14 is driven to ignite the first combustion area 2a. When the flame in the first combustion area 2a is detected (ignition is confirmed) by the first flame rod 15a, the process moves to the combustion process.

Next, in the combustion process, the combustion area in the combustion section 2 to be burned, the target rotation speed of the combustion fan 8, and the fuel flow rate of the fuel supply section 6 are set so that the calculated required heat amount can be supplied. The combustion fan 8 is then driven at the target rotation speed, and the fuel gas solenoid valve corresponding to the combustion area to be burned is opened to supply fuel at the set fuel flow rate, generating the required heat amount and supplying hot water at the hot water supply setting temperature.

When the water supply flow rate falls below a predetermined minimum flow rate due to the end of hot water supply use, the system transitions to the post-purge process. In the post-purge process, all open gas solenoid valves are closed to stop combustion in the combustion section 2, the target rotation speed is set to the scavenging rotation speed, and the combustion fan 8 is driven at the scavenging rotation speed for the post-purge time (e.g., 10 seconds). This exhausts the combustion gas so that it does not remain in the combustion section 2 and the heat exchange section 3. Finally, the combustion fan 8 is stopped, and the heating operation ends.

When the hot water supply device 1 is installed, 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 from this trial run in the memory unit 16b or in the memory area of the management server 20 as initial data at the time of installation.

During heating operation, the amount of condensed water introduced is usually equal to the amount of water discharged so that the level of the condensed water in the neutralization tank 9a is kept constant (water level M in Figure 1). However, for example, if microorganisms grow in the neutralization tank 9a and a biofilm is formed, or if finely divided neutralizing agent enters the drainage passage 9c, the flow of condensed water in the neutralization tank 9a or drainage passage 9c may be impeded, causing the water level to rise.

When the water level rises and the pair of electrode rods 9d detects a specified water level (water level H in Figure 1) for, for example, a period of time that is continuously longer than a preset reference time, the control unit 16 determines that a blockage has occurred in the neutralization tank 9a or drain passage 9c of the neutralization unit 9, and performs a safety operation to prohibit heating operation. The control unit 16 also notifies the user and, via the management server 20, for example, a service shop, of the blockage. The user or service shop, having learned of the occurrence of this malfunction, will arrange for inspection and repair.

For the user of the water heater 1, it is undesirable for the safety operation to suddenly cause the water heater 1 to become in an inconvenient state where it cannot be used. Therefore, if the control unit 16 detects signs of blockage in the neutralization tank 9a or the drain passage 9c before performing the safety operation, it notifies the service shop via the management server 20 that there are signs of blockage and prompts them to inspect it. This function for detecting signs of blockage in the neutralization tank 9a or the drain passage 9c will be explained based on the flowchart of the blockage sign detection control in Figure 4. In the figure, Si (i = 1, 2, ...) represents a step.

When the heating operation starts, the air that was trapped in the pre-purge process is exhausted and fresh air is introduced, and in the next ignition process, the ignition device 14 ignites the combustion section 2, after which the combustion process starts and the blockage prediction detection control starts. In S1, since condensed water is generated during the heating operation and introduced into the neutralization tank 9a, it is determined whether or not the heating operation is in progress. If the determination in S1 is No, the blockage prediction detection control ends. If the determination in S1 is Yes, proceed to S2.

Next, in S2, it is determined whether the pair of electrodes 9d of the water level detection means detects a predetermined water level. If the determination in S2 is No, the process returns to S1. If the determination in S2 is Yes, the process proceeds to S3.

In S3, the time during which the pair of electrodes 9d detects the specified water level (detection duration) is acquired, and the process proceeds to S4. In S4, it is determined whether this detection duration is equal to or longer than a preset reference time. The reference time is set to a time during which condensed water does not flow from the heat exchange section 3 to the combustion section 2, for example, 60 seconds.

If the determination in S4 is Yes, the process proceeds to S5, where the heating operation is stopped in S5 to prevent condensed water from flowing into the combustion section 2, and the process proceeds to S6. Then, in S6, the heating operation is prohibited and the process proceeds to S7, where a notification is given that a blockage has occurred in the neutralization tank 9a or the drain passage 9c, and the blockage prediction detection control is terminated. The above steps S5 to S7 correspond to normal safety operations.

On the other hand, if the determination in S4 is No, the process proceeds to S8. Then, in S8, it is determined whether or not the pair of electrode rods 9d no longer detects the specified water level. After the amount of drainage relative to the amount of condensed water introduced temporarily decreases and exceeds the specified water level, the cause of this, for example a biofilm or neutralizing agent, may be washed away and the water may be drained normally, so this is the step in which it is determined whether or not the specified water level is being detected temporarily. If the determination in S8 is No, the water is still above the specified water level, so the process returns to S3. If the determination in S8 is Yes, the process proceeds to S9, where the number of times the specified water level has been detected is incremented by 1, and the process proceeds to S10.

In S10, it is determined whether the number of times the specified water level has been detected is equal to or exceeds a reference number. The reference number is the number of times at which it is determined that a sign of blockage in the neutralization tank 9a or the drain passage 9c has been detected, and is set in advance, for example, based on experiments. If the determination in S10 is No, the process returns to S1. If the determination in S10 is Yes, the process proceeds to S11.

In S11, it is determined whether or not a sign of blockage in the neutralization tank 9a or drain passage 9c of the neutralization unit 9 has been detected and not yet reported. Since it is sufficient to report it once, if the determination in S11 is No, the process returns to S1. If the determination in S11 is Yes, the process proceeds to S12, where it is reported in S12 that a sign of blockage in the neutralization tank 9a or drain passage 9c of the neutralization unit 9 has been detected and the process returns to S1.

An example will be described in which the above-mentioned embodiment 1 is partially modified. The same parts as those in embodiment 1 are given the same reference numerals as those in embodiment 1, and the description thereof will be omitted.
If the control unit 16 of the hot water supply device 1 detects a sign of blockage in the neutralization tank 9a or the drain passage 9c of the neutralization unit 9 before performing a safety operation, the control unit 16 notifies the management server 20 that there is a sign of blockage in the neutralization tank 9a or the drain passage 9c of the neutralization unit 9, and urges, for example, a service shop to inspect the unit. The detection of a sign of blockage in the neutralization tank 9a or the drain passage 9c will be described with reference to the flowchart of the blockage sign detection control for the neutralization tank 9a or the drain passage 9c in FIG. 5.

S1 to S3 are the same as in Example 1, so their explanations are omitted. In S4, it is determined whether the detection duration acquired in S3 is equal to or longer than a preset reference time. If the determination in S4 is Yes, the process proceeds to S5. S5 to S7 are the same safety operations as in Example 1, so their explanations are omitted.

If the determination in S4 is No, proceed to S20, where it is determined whether the heating capacity of the currently executing heating operation is greater than the lower limit capacity of the water heater 1. Since the current heating capacity is the lower limit capacity, if the determination in S20 is No, return to S3. If the determination in S20 is Yes, proceed to S21.

In S21, the heating capacity is reduced by one step, for example by adjusting the fuel flow rate or the combustion region, and the heating operation is continued for a predetermined time (for example, 10 seconds), and then the process proceeds to S22. Since the amount of condensed water generated is proportional to the heating capacity, i.e., the amount of combustion, this step attempts to lower the water level in the neutralization tank 9a by reducing the amount of condensed water generated by reducing the heating capacity. Then, in S22, it is determined whether the pair of electrodes 9d of the water level detection means no longer detects the predetermined water level.

If the determination in S22 is No, the process returns to S3. If the determination in S22 is Yes, the process proceeds to S23, where it is determined whether the current heating capacity is less than the preset standard capacity. The neutralization unit 9 is configured so that the water level does not rise even when the heating operation is performed at the upper limit of heating capacity, but there are many cases where heating operation is performed that do not require the upper limit of heating capacity, and as long as the specified water level is not detected during heating operation at an intermediate heating capacity, there is no problem with the heating operation. On the other hand, if the heating capacity is set too low, it will not be possible to handle cases where the hot water supply flow rate is large. Therefore, it is determined that a sign of blockage in the neutralization tank 9a or drainage passage 9c of the neutralization unit 9 has been detected based on the preset standard capacity.

If the determination in S23 is Yes, proceed to S24, where a warning is given that a sign of blockage has been detected in the neutralization tank 9a or drain passage 9c of the neutralization unit 9, and proceed to S25. If the determination in S23 is No, proceed to S25. Then, in S25, the heating capacity of the subsequent heating operation is limited to the current heating capacity as the upper limit, and the process returns to S1.

The maximum flow rate of a hot water tap in a typical home is about 20 L/min, and there are limited cases where hot water is supplied at this maximum flow rate. Therefore, the standard capacity is preset to a heating capacity that can supply hot water, for example by raising the temperature by 25°C at a flow rate of 16 L/min. This allows heating operation to be performed with a reduced heating capacity to a level that does not interfere with normal use, and the detection of signs of blockage in the neutralization tank 9a or drain passage 9c of the neutralization unit 9 can be reported via the management server 20 to, for example, a service shop, to prompt action.

The operation and effects of the hot water supply device 1 will now be described.
In the above-mentioned first embodiment, the control unit 16 of the hot water supply device 1 performs a safety operation when the detection of a predetermined water level in the neutralization tank 9a continues for a reference time or more, and determines that a sign of blockage of the neutralization tank 9a or the drain passage 9c has been detected when the number of detections of the predetermined water level within the reference time reaches or exceeds the reference number. Therefore, since it is determined that a sign of blockage of the neutralization tank 9a or the drain passage 9c has been detected when a temporary blockage is detected the reference number of times, it is possible to detect a sign of blockage of the neutralization tank 9a or the drain passage 9c before heating operation is prohibited by the safety operation.

In the above-mentioned second embodiment, when the control unit 16 of the hot water supply device 1 detects a predetermined water level in the neutralization tank 9a, it attempts to stop detecting the predetermined water level by lowering the heating capacity to reduce the amount of condensed water generated. Then, if the heating capacity when the predetermined water level is no longer detected is less than the standard capacity, it is determined that a sign of blockage of the neutralization tank 9a or the drain passage 9c has been detected. On the other hand, if the detection of the predetermined water level continues for more than the standard time, a safety operation is performed. Therefore, since it is determined that a sign of blockage of the neutralization tank 9a or the drain passage 9c has been detected based on the heating capacity when the tank is not completely blocked, a sign of blockage of the neutralization tank 9a or the drain passage 9c can be detected before heating operation is prohibited by the safety operation.

Before the heating operation is prohibited by the safety operation, the control unit 16 of the water heater 1 issues an alert to encourage inspection of the neutralization unit 9 if it detects signs of blockage in the neutralization tank 9a or the drain passage 9c. Therefore, by inspecting and replacing the neutralization tank 9a or the drain passage 9c before the safety operation, it is possible to avoid the inconvenient situation in which the water heater 1 suddenly becomes unusable due to the safety operation.

In addition, those skilled in the art can implement the above-described embodiments in various modified forms without departing from the spirit of the present invention, and the present invention includes such modified forms.

1: Water heater 2: Combustion section 2a: First combustion region (ignition region)
2b: Secondary combustion zone (fire-transfer zone)
2c: third combustion region 2d: fourth combustion region 3: heat exchange section 3a: first heat exchanger 3b: second heat exchanger 3c: drain pan 4: water supply section 4a: water supply passage 4b: water supply branch passage 4c: water supply flow rate sensor 4d: water supply temperature sensor 5: hot water outlet section 5a: hot water outlet passage 5b: hot water outlet temperature sensor 5c: hot water supply temperature sensor 6: fuel supply sections 6a to 6d: first to fourth gas solenoid valves 6e: fuel flow rate adjustment valve 7: exhaust port 8: combustion fan 9: neutralization section 9a: neutralization tank 9b: introduction passage 9c: drain passage 9d: pair of electrodes (water level detection means)
REFERENCE SIGNS LIST 10: Flow rate control valve 11: Hot water tap 14: Ignition device 15a: First frame rod 15b: Second frame rod 16: Control unit 16a: Calculation unit 16b: Memory unit 16c: Communication unit 17: Operation terminal 18: Communication gateway 19: Communication network 20: Management server

Claims (3)

A hot water supply device comprising a combustion section, a fuel supply section which supplies fuel to the combustion section, a combustion fan which supplies combustion air to the combustion section, a heat exchange section having a heat exchanger which recovers latent heat from exhaust gas from combustion, a neutralization section which neutralizes condensed water produced in the heat exchange section, a water supply section, a hot water discharge section, and a control section which controls a heating operation which uses the combustion heat of the combustion section to discharge hot water heated in the heat exchange section, wherein the neutralization section has a neutralization tank which contains a neutralizing agent, an introduction passage which introduces condensed water to the neutralization tank, a drainage passage which drains the neutralized condensed water to the outside, and a water level detection means which detects the water level of the condensed water in the neutralization tank, and when the water level detection means detects a predetermined water level for a reference time or more, the control section determines that the neutralization tank or the drainage passage has been clogged and performs a safety operation which prohibits the heating operation,
The control unit is characterized in that it is equipped with a blockage precursor detection function that determines that a precursor to blockage of the neutralization tank or the drain passage has been detected when the number of times that the water level detection means detects the specified water level for a period of less than the reference time becomes equal to or exceeds a preset reference number. A hot water supply device comprising a combustion section, a fuel supply section which supplies fuel to the combustion section, a combustion fan which supplies combustion air to the combustion section, a heat exchange section having a heat exchanger which recovers latent heat from exhaust gas from combustion, a neutralization section which neutralizes condensed water produced in the heat exchange section, a water supply section, a hot water discharge section, and a control section which controls a heating operation which uses the combustion heat of the combustion section to discharge hot water heated in the heat exchange section, wherein the neutralization section has a neutralization tank which contains a neutralizing agent, an introduction passage which introduces condensed water to the neutralization tank, a drainage passage which drains the neutralized condensed water to the outside, and a water level detection means which detects the water level of the condensed water in the neutralization tank, and when the water level detection means detects a predetermined water level for a reference time or more, the control section determines that the neutralization tank or the drainage passage has been clogged and performs a safety operation which prohibits the heating operation,
The control unit is characterized in that, when the water level detection means detects the specified water level, it reduces the heating capacity until the amount of condensation generated decreases and the specified water level is no longer detected, and when the heating capacity when the specified water level is no longer detected falls below a predetermined standard capacity, it determines that a sign of blockage in the neutralization tank or the drain passage has been detected. The hot water supply device according to claim 1 or 2, characterized in that the control unit issues a notification to encourage inspection of the neutralization unit when it is determined that the blockage prediction detection function has detected a blockage prediction in the neutralization tank or the drain passage.