JPH09119633A - Hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve property of safety by a method wherein the threshold value of a fan voltage is compared with the voltage value of a fan by a fan voltage comparing circuit during fan remaining operation, wherein hot-water supply is stopped and only the fan is rotated for a predetermined period of time, or after finishing it and when the voltage value of the fan is lower than the threshold value, reoperation is made impossible. SOLUTION: When a hot-water supplier is operated to supply hot-water and the amount of water is decided that it has arrived at the water amount of extinction, a proportional control valve 2 and a main solenoid valve 1 are closed. When combustion is stopped, a fan remaining timer is started. Thereafter, when the timer is finished, the fan 3 is not stopped and arrives at the maximum set rotation, however, a deciding timer is started at the same time and the threshold valve of a fan voltage is decided by a fan voltage comparing circuit in a control means 8. In this case, the exhaust route of the hot-water supplier is brought into blocked condition and when a fan voltage is lower than a set threshold value, the fan 3 is stopped and a reoperation prohibiting command is stored into a memory whereby the hot-water supplier is brought into a condition that it can not be reused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the voltage value of a fan, and before the equipment becomes unsafe due to incomplete combustion,
The present invention relates to a hot water supply device that prohibits restarting.

[0002]

2. Description of the Related Art Conventionally, the structure of this type of hot water supply apparatus is the same as that shown in FIG. 2 of the present invention. By opening the faucet 16, water flows from the water supply port 11 to the heat exchanger 5 via the water amount sensor 9, and if the signal of the water amount sensor 9 is equal to or more than the ignition water amount, the fan 3 rotates and the ignition electrode After the discharge of 15 is started, the original solenoid valve 1 and the proportional control valve 2 are opened and the burner 4 is ignited. The flame ignited by the burner 4 is detected by the flame detection device 14 and maintains combustion.

The water in the heat exchanger 5 heated by the flame of the burner 4 becomes hot water, which is discharged from the faucet 16 through the hot water thermistor 10 and the hot water outlet 12. The temperature of the hot water discharged is
The control means 8 calculates the signal of the hot water thermistor 10 and compares it with a set temperature (not shown) set by the external control means 17 (remote control) for remote operation, and outputs the proportional control valve 2 and the fan 3. Is adjusted and controlled to reach the set temperature. The air required for combustion is taken in from the air supply unit 7 provided in a part of the outer case 18, passes through the fan 3, the burner 4, the heat exchanger 5, and the exhaust unit 6, and is exhausted as exhaust gas.

Next, a sequence diagram of this water heater is shown in FIG.
0 shows a block diagram of the control means 8 in FIG. In S1, the external control means 17 sets the hot water temperature (not shown), and S
When the water faucet 16 is opened at 2, as shown in S3 to S11, the signals of the water amount sensor 9, the flame detection device 14, and the hot water thermistor 10 are input, and each set value and the threshold value are determined,
The fan 3, the original solenoid valve 1, and the proportional control valve 2 are controlled by the processor. It is determined in S12 that the amount of fire extinguishing water has been reached, and in S13 the proportional control valve 2 and the original solenoid valve 1 are closed. When the combustion is stopped, the fan remaining timer is started in S14.

The left fan has a function of preventing abnormal heating in the heat exchanger 5 due to residual heat of the burner 4 generated when the water faucet 16 is closed. Further, in the ignition operation during re-hot water, the fan 3 is rotated by the ON signal of the water amount sensor 9, the ignition electrode 15 is discharged, the burner 4 is ignited, and the heat exchanger 5 is heated. At this time, the water amount sensor 9 is turned on, the fan 3 rotates, and it takes time to increase the number of revolutions required for ignition, which deteriorates the stabilization of the hot water temperature at the time of re-releasing hot water. Even if the combustion is stopped, the fan is not stopped, and there is a function of preventing the delay of the ignition operation at the time of re-leaving hot water and stabilizing the hot water temperature.

When the fan remaining timer expires in S15, S
At 20, the fan 3 is stopped, and the re-operation standby state of S21 is entered.

[0007]

However, in such a sequence, the air supply unit 7, the fan 3, the heat exchanger 5,
Even when the exhaust unit 6 is clogged with dust or the like and combustion abnormality occurs due to insufficient air, it is not possible to detect the abnormality of the water heater.

A flame detecting device 14 is provided as a means for detecting the state of flame, but this function is used only for detecting the presence or absence of flame. A flame rod is generally used because of its quick response, but there is no correlation between the current generated by this flame rod and the combustibility (CO / CO2), and it is impossible to detect even if combustion is in an incomplete combustion state. Had challenges.

Therefore, an object of the present invention is to safely stop the hot water supply apparatus before the combustion reaches the incomplete combustion state.

[0010]

According to the hot water supply device of the present invention, a preset fan voltage threshold value is set while the hot water supply is stopped and the fan that rotates only the fan for a predetermined time is left, or after the end. It is provided with a fan voltage comparison circuit that compares the voltage value of the fan. According to the present invention, the hot water supply device can be stopped before the exhaust passage is clogged and incomplete combustion occurs due to insufficient combustion air.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The first means of the hot water supply apparatus of the present invention is a fan voltage comparison circuit provided in the control means in advance for determining the voltage value of the fan from the time when the combustion is stopped and the remaining fan is finished. Compare with the set fan voltage threshold. If this is below the threshold value, the control means is provided with a sequence for stopping the fan and prohibiting the operation.

The second means causes the fan to rotate for a certain period of time after the combustion is stopped and the remaining fan is finished. The voltage at that time is compared with a preset fan voltage threshold value by a fan voltage comparison circuit provided in the control means, and if it is less than the threshold value, it is stored in the memory of the control means. If the number of times of storage is equal to or more than the number of times of storage previously set in the control means and is continuously less than or equal to the threshold value, the control means is provided with a sequence for stopping the fan to prohibit the operation.

Further, the third means is provided with a sequence for displaying and notifying an abnormality by the notifying means provided in the external control means when the restart is prohibited.

The fourth means is a fan voltage comparison circuit provided in the control means, and determines whether the fan voltage value is less than or equal to a preset threshold value. When the number of determinations of being less than or equal to the threshold value continues for the number of times preset by the control means or more, the abnormality occurrence timer is started. At the same time, the control means and the external control means are provided with a sequence which is displayed and notified to the user by the notifying means and can be normally used until the abnormality occurrence timer expires.

Further, a fifth means is a fan voltage comparison circuit provided in the control means, and when the fan voltage value is equal to or less than a preset threshold value or more than a preset number of times in the control means, A command for limiting (down) the output of the proportional control valve to the output set in the control means is stored in the memory. At the same time, the abnormality occurrence timer is started, and the user is displayed and informed by the notifying means provided in the external control means, and the maximum output of the proportional control valve output is limited (down) until the abnormality occurrence timer expires. The control means and the external control means are provided with usable sequences.

According to the first means described above, the present invention provides
The fan voltage can be detected by rotating the fan while leaving the fan or after the fan is finished. At this time, if the exhaust path from the air supply of the hot water supply device is clogged with dust, etc., and there is a combustion abnormality due to insufficient air, the fan voltage has dropped, so it is possible to detect this fan voltage drop value. become. Combustion can be safely stopped and operation can be prohibited by comparing with a preset threshold value by the control means.

According to the second means, the fan voltage is temporarily an external factor during the fan voltage determination (for example, a strong back pressure is applied to the exhaust part during strong wind due to a bad installation of the water heater).
It is possible that In this case, if the fan voltage value is not more than the threshold value and is not continuous for the number of times set in the control means or more, the combustion abnormality is not determined, so that the malfunction can be prevented. Moreover, it is possible to reliably and safely stop combustion and prohibit operation.

Further, according to the third means, when the hot water supply device is judged to be defective in installation due to an external factor such as a strong wind, and the restarting prohibition sequence is entered, the user is notified by the notification means provided in the external control means. Since the notification is given, the user can accurately grasp the installation state of the hot water supply device, and can respond promptly and accurately.

According to the fourth means, the fan voltage comparison circuit of the control means determines that an abnormality has occurred in the determination of the fan voltage, and the notification means allows the user to recognize that the water heater is abnormal. You can do it. At the same time, since the hot water supply device can be used for a certain period of time set in the control means after an abnormality occurs, there is a certain amount of time before repair can be performed, and the hot water supply device cannot be used until the failure is repaired. The period can be reduced.

Furthermore, according to the fifth means, since the maximum output of the water heater is limited (down) from the time when the control means determines that an abnormality has occurred in the fan voltage determination, The period until failure repair can be used safely (for example, the initial combustion state and C0 / CO2 are at the same level).

Further, by setting the combustion state of the hot water supply apparatus to the same level as the initial combustion state, it takes a certain amount of time for the hot water supply apparatus to reach an unsafe state. Until the period is extended, the user can use it safely for a long time. In particular, the reason why the determination of the fan voltage is set after the completion of combustion after leaving the fan is as follows.

First, when the fan voltage determination is set during combustion, the fan rotation speed greatly changes depending on the combustion load, and it is difficult to set the threshold value.

Second, if the fan voltage is set before combustion, the fan voltage changes largely due to the hardening of the bearing grease of the fan when the outside air temperature is different, especially at low temperatures, and the threshold value is set also in this case. It is difficult.

A first embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3 and 4. The configuration shown in FIG. 2 is the same as the configuration described in the related art, and thus the description is omitted. In FIG. 1, S1 to S of the sequence
The operation up to 15 is the same as the operation described in the conventional technique, and thus the description thereof is omitted.

When the fan remaining timer of S15 expires,
The fan 3 does not stop and reaches the maximum set rotation. At the same time, the determination timer of S17 is started, and the threshold value of the fan voltage of S18 is determined by the fan voltage comparison circuit 8b of the control means 8 shown in FIG.

At this time, the path from the air supply of the water heater to the exhaust air is
If the fan voltage comparison circuit 8b determines that the fan voltage is equal to or lower than the threshold value set by the control means 8 in the case where the fan voltage is blocked due to dust or the like, the fan 3 is stopped in S22, and in S23. The restarting prohibition command is stored in the memory 8a of the control means 8 shown in FIG. 4, and the hot water supply device is put into a state where it cannot be reused.

The voltage value of the fan 3 when the fan is left in S14 changes as shown in FIG. The voltage of the fan 3 is high at the beginning and is low from the middle because when the faucet 16 is opened to closed, the inside of the heat exchanger 5 is heated by the residual heat of the burner 4, and the temperature set by the external controller 17 is set. Get higher. If hot water is again tapped at this point, the hot water in the heat exchanger 5 will be tapped.

In order to reduce this phenomenon, when the hot water is stopped, the rotation of the fan 3 is first made large (strong rotation) to prevent the temperature inside the heat exchanger 5 from becoming higher than the set temperature.
If the fan 3 continues to rotate strongly as it is, the temperature inside the heat exchanger 5 becomes lower than the temperature set by the external control device 17 this time, so the fan speed is reduced to prevent the temperature inside the heat exchanger 5 from decreasing. It is low.

The fan-remaining time of the fan 3 is set to about 5 minutes based on a monitor survey of the actual shower usage. After the fan remaining timer ends, the fan rotation speed is maximized in S16, the determination timer is started in S17, and the fan voltage value set by the control means 8 is set to the maximum value by the control means 8 until the timer ends. The fan voltage value that is being rotated is compared and determined in S18.

As a result, if the voltage value is equal to or lower than the threshold value, the fan 3 is stopped in S22, and the restart prohibition command is stored in the memory 8a of the control means 8 in S23.

If the fan voltage value is equal to or higher than the threshold value in S18, the fan 3 is stopped in the normal use state in S20 and S21, and the re-operation standby state is set.

As described above, by monitoring the fan voltage value after the fan is left, it is determined whether the hot water supply device is used in a safe state or whether the hot water supply device is in an abnormal state.
You can stop immediately.

The second embodiment will be described with reference to FIG. The operation from S1 to S17 in the sequence is the same as that of the first embodiment.

In the fan voltage comparison circuit 8b of the control means 8, S
When it is determined in 18 that the fan voltage is equal to or lower than the threshold value, the number of times is stored in the memory 8a of the control means 8 in S24. Next, the number of times stored in the memory 8a in S25 is compared with the number of times preset in the control means 8, and if the number of times of storage is continuous and equal to or more than the set number, the fan 3 is stopped in S22 and S23. Then, the restart instruction is stored in the memory 8a of the control means 8.

If the voltage of the fan 3 is above the threshold value in S18, the information stored in the memory 8a is S3.
Erase with 0. This makes it possible to determine a fan voltage drop due to strong backwind to the exhaust unit when determining the fan voltage, prevent malfunctions due to this sequence, and detect only clogging abnormalities from the air supply to the exhaust path of the water heater. be able to.

Next, after the judgment timer expires in S19,
The fan 3 is stopped in S20, and the re-operation standby state is set in S21.

The third embodiment will be described with reference to FIG. The operation from S1 to S17 in the sequence is the same as that of the first embodiment.

In the fan voltage comparison circuit 8b of the control means 8, S
When it is determined in 18 that the fan voltage is equal to or lower than the threshold value, the number of times is stored in the memory 8a of the control means 8 in S24. Next, the number of times stored in the memory 8a in S25 is compared with the number of times set in the control means 8, and if the number of times of storage is continuous and equal to or more than the set number of times, the fan 3 is operated in S22.
And the remote controller (external control means 17) is informed of the abnormality in S26. Here, the user can quickly recognize the abnormality of the water heater.

Further, by storing the re-operation prohibition command in the memory 8a of the control means 8 in S23 at the same time as the abnormality notification, it is possible to prevent the user from using the water heater in an abnormal state.

If the voltage of the fan 3 is above the threshold value in S18, the information stored in the memory 8a is S3.
It is erased by 0, and after the judgment timer expires in S19, S2
At 0, the fan 3 is stopped, and at S21, the re-operation standby state is set.

The fourth embodiment will be described with reference to FIG. The operation is the same as that of the first embodiment from S1 to S17 of the sequence.

In the fan voltage comparison circuit 8b of the control means 8, S
When it is determined in 18 that the fan voltage is equal to or lower than the threshold value, the number of times is stored in the memory 8a of the control means 8 in S24. Next, the number of times stored in the memory 8a in S25 is compared with the number of times set in the control means 8, and if the number of times of storage is continuous and equal to or more than the set number of times, the abnormality occurrence timer is started in S27, At the same time a remote control (external control means 1
Inform 7) of the abnormality.

Next, when the abnormality occurrence timer ends in S28, the fan 3 is stopped, and in S23, the memory 8 of the control means 8 is stopped.
Store the restart prohibition command in a. This means that by setting the fan voltage judgment threshold value to the safe side, the time of the abnormality occurrence timer can be freely selected, and the time until the hot water supply device is disabled can be set arbitrarily. become.

As a result, the user does not suddenly become unable to use the hot water supply device, but can safely use the hot water supply device until he / she recognizes an abnormality in the hot water supply device, requests failure repair, and inspects. .

If the voltage of the fan 3 is above the threshold value in S18, the information stored in the memory 8a is S3.
It is erased by 0, and after the judgment timer expires in S19, S2
At 0, the fan 3 is stopped, and at S21, the re-operation standby state is set. Similarly, the re-operation standby sequence from S19 to S21 is executed until the abnormality occurrence timer started at S27 expires.

The fifth embodiment will be described with reference to FIGS. 8 and 9. The operation from S1 to S17 in the sequence is the same as that of the first embodiment.

In the fan voltage comparison circuit 8b of the control means 8, S
When it is determined in 18 that the fan voltage is equal to or lower than the threshold value, the number of times is stored in the memory 8a of the control means 8 in S24. Next, the number of times stored in the memory 8a in S25 is compared with the set number set in the control means 8, and if the stored number is continuous and equal to or more than the set number, the maximum output of the proportional control valve 2 in S29. A command for limiting (down) from A ₀ to A ₁ shown in FIG. 9 is stored in the control means 8 and the memory 8a.

At the same time, the remote controller (external control means 17) is informed of the abnormality. At this time, the user can recognize the abnormality of the hot water supply device and take a quick response.

Next, in S27, the abnormality occurrence timer is started, and from S19 to S until the abnormality occurrence timer ends.
Since the restarting waiting sequence 21 is executed, the user is not prevented from using the hot water supply device.

In S28, the abnormality occurrence timer expires, the fan 3 is stopped, and in S23, the restart prohibition command is stored in the memory 8a of the control means 8. At this point, the user cannot use the water heater.

If the voltage of the fan 3 is above the threshold value in S18, the information stored in the memory 8a is S3.
It is erased by 0. This means that unless the fan voltage becomes lower than the threshold value continuously, it is not judged as an abnormality of the water heater, whether it is due to a temporary back pressure applied to the exhaust part, or an abnormality of the water heater. It is possible to determine whether the abnormality is due to clogging of the.

If there is no abnormality in the hot water supply device, the determination timer ends in S19, the fan 3 stops in S20, and S21.
Then, it will be in the re-operation standby state.

Next, the combustion characteristics when the capacity is limited (down) in S29 will be described with reference to FIG. The X-axis represents the output of the proportional control valve 2, the first Y-axis represents CO / CO2 discharged from the exhaust unit 6, and the second Y-axis represents the voltage value of the fan 3 in the determination timer.

The dotted line shows the combustion characteristics when the hot water supply device is in normal combustion. The solid line indicates a state in which the path from the air supply section 7 to the exhaust section 6 from the air supply to the exhaust is clogged with dust or the like.

During normal combustion and when the hot water supply device is clogged,
CO / CO2 when the proportional control valve 2 has a maximum output is changed from C ₀ to C _1. This is because the amount of air supplied from the fan 3 decreases because the supply / exhaust path is clogged.

When the amount of air sent from the fan 3 decreases, the work of the fan 3 decreases and the fan voltage also decreases from B ₀ to B ₁ . This is because the same phenomenon occurs even when the combustion is stopped, so this voltage drop is detected and the fan voltage comparison circuit 8b of the control means 8 determines that the water heater is abnormal. .

By controlling (down) the maximum output of the proportional control valve 2 from A ₀ to A ₁ from the time when the abnormality occurs, the value of CO / CO ₂ is reduced from C ₁ to C ₂ and CO during normal combustion is reduced. / It becomes the same level as CO2. As a result, the user can safely use the hot water supply device until the trouble is repaired.

[0058]

As is apparent from the above description, the hot water supply apparatus of the present invention has the following effects. According to the first aspect of the present invention, even when the path from the air supply unit to the exhaust unit of the hot water supply device is clogged with dust or the like and abnormal combustion occurs due to lack of air, the automatic combustion is performed before the combustion device enters a dangerous state. Since the appliance can be stopped mechanically and safely, it is possible to prevent the user from using the water heater in an unsafe state.

In the invention according to claim 2, dust or the like is clogged in the path from the air supply part to the exhaust part of the hot water supply device, causing the hot water supply device to be incompletely burned due to insufficient air, or a temporary phenomenon (strong wind). It is possible to judge whether it is incomplete combustion due to reverse air pressure applied to the exhaust part due to () by incomplete combustion multiple times.
Since it is possible to accurately determine the abnormality of the combustion device, it is possible to prevent malfunction due to this sequence.

In the invention according to claim 3, the abnormality of the hot water supply device can be accurately determined, and the user can be notified by the notification means provided in the external control means why the hot water supply device cannot be used. The failure repair can be carried out quickly and the details of the failure can be accurately judged, and the user can shorten the unusable time of the water heater.

Further, in the invention according to claim 4, since it is possible to notify the user of the abnormality of the hot water supply device in advance, it is possible to prevent the hot water supply device from suddenly becoming unusable, and an abnormality occurs in the hot water supply device. However, the failure can be repaired before it becomes dangerous, and the details of the failure can be accurately grasped by the external control means, so that the time required for the repair can be shortened.

Furthermore, in the invention according to claim 5,
When an abnormality occurs in the water heater, the user recognizes the abnormality of the water heater, and until the failure repair is requested and completed, the combustion state of the water heater is returned to the initial state. It is possible to prevent the hot water supply device from being in an abnormal and dangerous state when it takes time to repair the hot water supply device or when it is delayed for the user to recognize the abnormality of the hot water supply device. In addition, it is possible to safely stop the combustion device and prohibit reuse.

Further, since the fan voltage threshold is set after the end of the fan, the correlation between the fan voltage and the rotation speed is less likely to be affected by the environmental temperature and the combustion state before the combustion device is stopped. Therefore, the accuracy of this sequence can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a sequence of a hot water supply device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of the device.

FIG. 3 is a characteristic diagram of a fan voltage with respect to an elapsed time while a fan is left in the sequence of the device.

FIG. 4 is a block diagram of control means of the device.

FIG. 5 is a flowchart showing a sequence of the hot water supply device according to the second embodiment of the present invention.

FIG. 6 is a flowchart showing a sequence of the hot water supply device according to the third embodiment of the present invention.

FIG. 7 is a flowchart showing a sequence of the hot water supply device according to the fourth embodiment of the present invention.

FIG. 8 is a flowchart showing a sequence of the hot water supply device according to the fifth embodiment of the present invention.

[Fig. 9] Combustion characteristic diagram when the supply / exhaust path of the device is clogged

FIG. 10 is a sequence diagram of a conventional water heater.

FIG. 11 is a block diagram of control means of the device.

[Explanation of symbols]

 1 proportional control valve 3 fan 4 burner 5 heat exchanger 8 control means 8a memory 8b fan voltage comparison circuit 10 hot water thermistor 17 external control means

Claims (5)

[Claims] 1. A burner for burning fuel, a fan for sending air required for combustion, a heat exchanger for transferring heat generated by the burner to water, and a temperature of water heated by the heat exchanger. A hot water thermistor to detect, a proportional control valve that adjusts the output of the burner so that the signal of the hot water thermistor reaches a set temperature, and the output of the proportional control valve and the fan is controlled from the signal of the hot water thermistor. The control means and a fan voltage comparison circuit that detects and compares the voltage of the fan are provided, and the control means sets the fan in advance while stopping the hot water supply and rotating only the fan for a predetermined time, or after the end. Hot water supply having a sequence in which the fan voltage threshold value and the voltage value of the fan are compared by the fan voltage comparison circuit, and if the voltage value is equal to or lower than the threshold value, restarting is impossible. Location. 2. A burner for burning fuel, a fan for sending air necessary for combustion, a heat exchanger for transferring heat generated by the burner to water, and a temperature of water heated by the heat exchanger. A hot water thermistor to detect, a proportional control valve that adjusts the output of the burner so that the signal of the hot water thermistor reaches a set temperature, and the output of the proportional control valve and the fan is controlled from the signal of the hot water thermistor. The control means and a fan voltage comparison circuit that detects and compares the voltage of the fan are provided, and the control means sets the fan in advance while stopping the hot water supply and rotating only the fan for a predetermined time, or after the end. The fan voltage threshold value and the fan voltage value are compared by the fan voltage comparison circuit, and if the fan voltage is less than or equal to the threshold value, the value is stored in a memory, and the number of times of this storage is continuous and set. If more, the hot water supply device provided with a control means having a sequence that restarting operation becomes impossible. 3. A burner for burning fuel, a fan for sending air necessary for combustion, a heat exchanger for transferring heat generated by the burner to water, and a temperature of water heated by the heat exchanger. A hot water thermistor to detect, a proportional control valve that adjusts the output of the burner so that the signal of the hot water thermistor reaches a set temperature, and the output of the proportional control valve and the fan is controlled from the signal of the hot water thermistor. The control means and a fan voltage comparison circuit that detects and compares the voltage of the fan are provided, and the control means sets the fan in advance while stopping the hot water supply and rotating only the fan for a predetermined time, or after the end. The fan voltage threshold value and the fan voltage value are compared by the fan voltage comparison circuit, and if the fan voltage is less than or equal to the threshold value, the value is stored in a memory, and the number of times of this storage is continuous and set. If above, the notification means provided in the external control means, and notification if hot water supply apparatus provided with a control means having a sequence that restarting operation becomes impossible. 4. A burner for burning fuel, a fan for sending air necessary for combustion, a heat exchanger for transferring heat generated by the burner to water, and a temperature of water heated by the heat exchanger. A hot water thermistor to detect, a proportional control valve that adjusts the output of the burner so that the signal of the hot water thermistor reaches a set temperature, and the output of the proportional control valve and the fan is controlled from the signal of the hot water thermistor. The control means and a fan voltage comparison circuit that detects and compares the voltage of the fan are provided, and the control means sets the fan in advance while stopping the hot water supply and rotating only the fan for a predetermined time, or after the end. The fan voltage threshold value and the fan voltage value are compared by the fan voltage comparison circuit, and if the fan voltage is less than or equal to the threshold value, the value is stored in a memory, and the number of times of this storage is continuous and set. From the time point above, the abnormality occurrence timer that integrates the operating time is started, and the notification means provided in the external control means notifies that fact, and restarts until the abnormality occurrence timer ends A hot water supply apparatus including a control unit having a sequence for prohibiting restarting after the generation timer ends. 5. A burner for burning fuel, a fan for sending air necessary for combustion, a heat exchanger for transferring heat generated by the burner to water, and a temperature of water heated by the heat exchanger. A hot water thermistor to detect, a proportional control valve that adjusts the output of the burner so that the signal of the hot water thermistor reaches a set temperature, and the output of the proportional control valve and the fan is controlled from the signal of the hot water thermistor. The control means and a fan voltage comparison circuit that detects and compares the voltage of the fan are provided, and the control means sets the fan in advance while stopping the hot water supply and rotating only the fan for a predetermined time, or after the end. The fan voltage threshold value and the fan voltage value are compared by the fan voltage comparison circuit, and if the fan voltage is less than or equal to the threshold value, the value is stored in a memory, and the number of times of this storage is continuous and set. From the time point above, a command to limit (down) the maximum output of the proportional control valve is stored in the memory, the abnormality occurrence timer is started, and a notification means provided in the external control means notifies that effect. A water heater provided with a control means having a sequence for operating in a state in which the maximum output of the proportional control valve is limited (down) until the abnormality occurrence timer expires, and after the abnormality occurrence timer expires.