JPH0972610A - Hot water supply equipment and detecting method for failure of temperature-detecting means of hot water supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect quickly an out-of-over temperature-detecting means out of three or more temperature detecting means by comparing temperature information outputted from the individual temperature detecting means and by judging one temperature detecting means as failing when a difference of the temperature information thereof from that outputted from other temperature detecting means exceeds a prescribed value. SOLUTION: A temperature sensor S1 detects the temperature of water entering hot water supply equipment 1 and a temperature sensor S2 detects the temperature of the water after it is heated by a heat exchanger 16, while a temperature sensor S3 detects the temperature of hot supply water after the hot water obtained by the heat exchanger 16 is mixed with water from a bypass passage 8. Water is made to flow through a water pipe 6 and output values of the temperature sensors S1-S3 are compared in the same temperature condition in a state wherein combustion of gas is not conducted. When a failure occurs in a system of any temperature sensor, the failing temperature sensor alone outputs an abnormal value different from ones of other temperature sensors and sends it to CPU 22a and, therefore, the temperature sensor failing can be detected. Accordingly, it is possible to shorten a time for a repair operation and to improve operability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus, and more particularly to detecting failure of a temperature detecting means provided in a water pipe in the hot water supply apparatus.

[0002]

2. Description of the Related Art Home water heaters can be roughly classified into a single-function machine dedicated to hot water supply or bath heating and a multi-function machine having both hot water supply and bath reheating functions. The mainstream is a multi-function machine that also has the function of reheating the bath, and by incorporating a microprocessor, it prevents start / stop of hot water supply operation, adjustment of hot water supply temperature, incomplete combustion, extinction, overheating, etc. The mainstream is a device that electrically controls safety devices for safety.

For example, a brief description of an example of hot water supply temperature control of a gas water heater will be given to the gas water heater depending on the hot water temperature set by the user and the amount of water input depending on the opening of the hot water tap operated by the user. The temperature of the incoming water of the water, the temperature of the water immediately after being heated by the heat exchanger, and the temperature of the hot water discharged from the hot water tap are monitored by a temperature sensor (usually a thermistor), and the CPU
Is automatically controlled on the basis of the temperature information output from these temperature sensors, the water flow rate, the gas flow rate, and the air volume sent by the combustion fan.

Therefore, when the temperature sensor (including the temperature sensor main body for detecting the temperature and its drive circuit, a series of systems such as a detection circuit) has a failure such as a disconnection, a short circuit, or an abnormal output, the hot water temperature control function properly. Disappear. For example, a thermistor that is usually used as a temperature sensor detects temperature by utilizing the fact that the electric resistance value changes greatly as the temperature changes.However, the output of this resistance value deviates from the output value under normal conditions and is output. If such a failure occurs and temperature information lower than the actual temperature is sent to the CPU, the CPU may find that the hot water temperature does not reach the set temperature even if the burnup for heating the water is increased. Since the water flow rate is controlled so as to be narrowed, the phenomenon that the amount of hot water that comes out even when the hot water tap is fully opened occurs to the user is always small. Also, if the thermistor starts sending temperature information higher than the actual temperature to the CPU,
However, since it is judged that it has reached the set temperature even though the actual hot water supply temperature has not reached the set temperature, it does not heat more than that, so it will be a user, The phenomenon that the hot water that comes out does not reach the set temperature occurs.

When the user notices such a phenomenon, he / she contacts a repair service center in the area and asks a repair worker for repair. The repair worker who receives the notification may inspect the thermistor because of the phenomenon, and will perform the inspection.

[0006]

Since the CPU constantly monitors the temperature information output by the thermistor, if the resistance value becomes 0 or infinite, for example, when the thermistor system is short-circuited, there is such a possibility on the CPU side. The thermistor that outputs a value that cannot be obtained can be determined to be defective.

However, when the resistance value output from the thermistor is out of order as described above, all thermistors must be inspected one by one. Furthermore, the thermistor must judge whether the output value is normal or abnormal by the resistance value, and the thermistor has different specifications depending on the manufacturer.To check the output abnormality of the thermistor, refer to the manual etc. Since it is necessary to check the consistency between the measured temperature and the resistance value while measuring the value, it takes time and labor and work efficiency is not good.

In addition, since it is conceivable that the thermistor may be the cause of failure not only in the thermistor body but also in the wiring system of its drive circuit and detection circuit, in order to determine where the failure occurs during inspection by the tester. Must carry out inspection work at all expected locations. Recently, there is a demand for downsizing of the domestic hot water supply system, and the parts inside the hot water supply system are stored very compactly in a small space.So, especially when you want to check the wiring system, you have to remove the control board to remove the hot water supply system. In many cases, it cannot be inspected unless it is pulled out, and it takes a lot of time and effort to identify the cause of failure.

However, if the thermistor system in which at least a plurality of thermistors are provided has an abnormality, the efficiency of repair can be greatly improved. This is because the entire system of one thermistor can be used as a replacement unit for parts and the entire system can be replaced at the time of repair.

The present invention has been made in view of the above problems, and an object of the present invention is to quickly and appropriately identify a defective temperature detecting means out of three or more temperature detecting means provided in a water pipe of a water heater. It is to provide a hot water supply device provided with a method capable of being detected and a determination means for determining its failure.

[0011]

In order to achieve the above object, the present invention provides a water pipe for introducing water from water supply and supplying heated water, and a heat exchanger provided in the middle of the water pipe. A burner for heating the heat exchanger, a gas supply pipe for supplying gas to the burner, and three or more temperature detection means provided for detecting the temperature in the water pipe, In a hot water supply device that controls the hot water supply temperature based on the temperature information output from the temperature detection means, water of the same temperature is caused to flow through the entire water pipe, and the temperature output from each of the temperature detection means based on the water of the same temperature. It is characterized in that the information is compared and it is judged that the temperature detecting means for outputting the temperature information whose difference from the temperature information output from the other temperature detecting means exceeds a predetermined value is out of order.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a hot water supply apparatus according to the present invention. The hot water supply apparatus 1 has a water pipe 6 for introducing water into the hot water supply apparatus 1 from tap water and discharging hot water, and a water pipe 6 on the way. The heat exchanger 16 provided in the heat exchanger 16, the burner 10 provided in the lower portion of the heat exchanger 16, and the gas supply pipe 7 for supplying gas to the burner 10.

The water pipe 6 is provided with a water amount sensor 2 for detecting that the hot water supply plug 23 provided on the downstream side of the hot water supply device 1 is opened and water flows out, and the temperature of the water entering the water pipe 6. A temperature sensor S1 provided for monitoring, a temperature sensor S2 provided for monitoring the hot water temperature in the water pipe 6 after passing through the heat exchanger 16, and a temperature of hot water supplied from the water pipe 6. A temperature sensor S3 provided for this purpose and a water amount control valve 19 are provided. Further, a bypass passage 8 for mixing hot water heated by the heat exchanger 16 with water before heating and discharging the hot water is provided in the middle of the water pipe 6.
There is provided a mixing valve 20 for mixing the hot water from and the water from the bypass passage 8 at an optimum ratio.

The gas supply pipe 7 has a source gas solenoid valve 17 and a switching solenoid valve 25 for starting and stopping the supply of gas.
26 and a gas proportional valve 18 for adjusting the supplied gas amount. Further, a spark plug 11 connected to an ignition device 9 and a flame rod 13 for detecting a flame are provided near the burner 10, and an air plug for promoting a gas combustion reaction is provided below the burner 10. A combustion fan 15 is provided for feeding in.

The operation of the water heater 1 is performed by the controller 22C.
It is controlled by the PU 22a. The CPU 22a receives the flowing water detection signal from the water amount sensor 2, and receives the controller 2
The start / stop of the rotation of the combustion fan 15, the start / stop of the spark of the ignition plug 11 by the ignition device 9, the opening / closing of the original gas solenoid valve 17 and the switching solenoid valves 25 and 26 are controlled via the temperature sensor. Receiving the temperature information detected in S1, S2, and S3, the rotation of the combustion fan 15, the operation of the gas proportional valve 18, the water amount control valve 19, and the mixing valve 20 are switched so that the hot water supply temperature becomes the temperature set by the user. Solenoid valve 25,
The operation of 26 is controlled via the controller 22.

On the other hand, in the memory 24, which is a fixed storage device connected to the CPU 22a, an operation program for performing normal hot water supply operation control of the hot water supply device 1, a failure diagnosis program for self-diagnosis of a failure, and a failure diagnosis. A program or the like for controlling the operation mode for the computer is stored.

Further, a remote control device 27 with a display unit for the user to set the hot water supply temperature and the like is provided outside the hot water supply device 1, and data such as the set temperature is transmitted to and received from the CPU 22a. The setting data and error code are displayed.

The temperature sensor S in this embodiment is
Normally, thermistors are used as 1, S2 and S3, but other ones may be used.

Next, the hot water supply operation of the hot water supply device 1 will be described.

When the hot water tap 23 is closed, the water pipe 6 is filled up to the mouth of the hot water tap 23 by the water pressure of the water supply. In this state, when the hot water tap 23 is opened, the water in the water pipe 6 flows out of the hot water tap 23 due to the water pressure, and as a result, the water amount sensor 2 operates to send a running water detection signal to the CPU 22.
to a. The water that has passed through the water amount sensor 2 is heat exchanger 1
The hot water heated by the heat exchanger 16 and the water passing through the bypass passage 8 are mixed and flow to the hot water tap 23.

The CPU 22a monitors the transmission of the running water detection signal from the water amount sensor 2. When the running water detection signal is received from the water amount sensor 2, the CPU 22a first starts the rotation of the combustion fan 15 via the controller 22 and then the spark plug. 11
To start the spark and to send a signal for opening the original gas solenoid valve 17 and the switching solenoid valve 26.

As a result, when gas is supplied to the burner 10 under normal conditions, the ignition plug 11 ignites and gas combustion starts, so that the flame rod 13 outputs a flame detection signal C
It is transmitted to the PU 22a. The CPU 22a monitors whether or not the flame detection signal is received from the frame rod 13 after the spark ignition operation is started, and if the flame detection signal is received,
Assuming that the operation has started normally, the hot water supply operation start control ends and the normal operation is started. After that, burner 10
The heat exchanger 16 is heated by this, the running water in the water pipe 6 is heated, and hot water is supplied from the hot water tap 23. When increasing the gas supply amount, the CPU 22a transmits a signal for opening the switching electromagnetic valve 25. CPU22a is temperature sensor S1, S
2, the combustion fan 1 receives the temperature signal indicating the temperature detected in S3 so that the hot water supply temperature becomes the temperature set by the user.
5, the operation of the gas proportional valve 18, the water amount control valve 19, the mixing valve 20, the operation of the switching electromagnetic valves 26, 25, etc. are controlled via the controller 22. Further, when the hot water discharge temperature, the water flow, the water pressure change, or the like changes during the hot water supply operation, the temperature sensors S1, S2, S3 and the water flow sensor 2 sense the temperature difference, and the set temperature difference is detected by the temperature sensors S1, S2, S3. And the deviation value is calculated based on the information from the water amount sensor 2, and the deviation value is switched to the solenoid valve 26, the gas proportional valve 18, the water amount control valve 19, the mixing valve 2.
Report to 0 and keep the set temperature.

By the way, the temperature sensor S1 is the temperature of the water entering the hot water supply apparatus 1, the temperature sensor S2 is the temperature of the water after being heated by the heat exchanger 16, and the temperature sensor S3 is the hot water heated by the heat exchanger 16 by-pass. The temperature sensors S1 to S3 are provided to detect the hot water supply temperatures after being mixed with the water from the passage 8, and when the hot water supply operation is normally performed.
Usually have different temperature values. Therefore, even if the output value of any of the temperature sensors S1 to S3 is abnormal, the CPU 22a cannot detect it.

However, if water is flowed through the water pipe 6 and gas combustion is not performed, the temperature sensor S is operated under the same temperature condition.
It becomes possible to compare the output values of 1 to S3. If S
If all the temperature sensors 1 to S3 are normal, almost the same output value is sent to the CPU 22a. On the other hand, if there is a failure in the temperature sensor system, only the failed temperature sensor outputs an abnormal value different from the other temperature sensors, and the CPU 2
2a, so that it is possible to detect a failed temperature sensor.

In the present embodiment, considering that the hot water supply device with the automatic temperature control function that is currently used often has three temperature sensors, three or more temperature sensors are used. The failure detection of the temperature sensor of the water heater having the above is targeted. In addition, the target is failure detection when one of three or more temperature sensors used is out of order. Since it is unlikely that two or more temperature sensors will fail at the same time, such a case is excluded.

Next, referring to FIGS. 1 and 2, C
A flow of operation of detecting a failure of the temperature sensor in the PU 22a will be described. FIG. 2 is a flow chart of failure detection of the temperature sensor according to the present embodiment.

The failure detection of the temperature sensor in the present embodiment is carried out when a repair worker visits the user to inspect the hot water supply device 1 in response to a repair request from the user.

The memory 24 connected to the CPU 22a stores a program for controlling an operation mode for failure diagnosis in addition to an operation program for normal hot water supply operation control.
The repair worker uses the CPU to diagnose the temperature sensor failure.
The diagnostic mode of this temperature sensor is started by connecting an external terminal device to 22a (S-1). Next hot water tap 2
3 is opened to start running water (S-2). In the normal hot water supply operation mode, when running water starts, the combustion fan 15
Rotation, spark of spark plug 11, original gas solenoid valve 17
And the switching solenoid valve 25 is sequentially opened to start the gas combustion, but in the diagnostic mode of the temperature sensor, the rotation of the combustion fan 15, the spark of the ignition plug 11, the source gas solenoid valve 17, and the switching solenoid are started even if running water starts. Since the valve 25 is not opened, the water in the water pipe 6 is not heated and the water of the same temperature flows in the entire water pipe 6. CPU22a is temperature sensor S1, S
2, output values T1, T after the start of flowing water output from S3
2, T3 is detected (S-3), the difference between the respective output values,
That is, (T1-T2), (T1-T3), (T2-T
The absolute value α of 3) is calculated (S-4). If all the temperature sensors S1 to S3 are normal, T1 to T3 show almost the same value. Therefore, the allowable error range is set in advance as a predetermined value, and it is determined whether or not all the calculated α are less than or equal to the predetermined value (S-5).

If all the calculated α's are equal to or less than a predetermined value, it is judged that all temperature sensors are normal (S-
6). On the other hand, if some of the α calculated in step (S-6) exceeds the predetermined value, it is first determined that both combinations of temperature sensors in which α is the predetermined value or less are normal (S-7). , And if α exceeds a predetermined value, it is determined that one of them is out of order (S-8). Then, the failed temperature sensor is specified from step (S-7) and step (S-8) (S-9), and the result is displayed on, for example, the remote control device 27 (S-10).

In the embodiment shown in FIGS. 1 and 2, the failure detection of the temperature sensor of the water heater having three temperature sensors was described, but the number of temperature sensors is not limited to three,
The present invention can be implemented in a similar manner in a hot water supply device having three or more temperature sensors.

Further, in the embodiment shown in the flow chart of FIG. 2, the means for judging the failure of the temperature sensor is provided inside the hot water supply apparatus, but in the portable terminal apparatus having the built-in CPU carried by the repair worker as described above. You may make it have a different judgment means. In this case, when the repair worker performs the repair work, the failure of the temperature sensor is judged by the judgment program stored in the terminal device side by connecting the terminal device to the CPU 22a in the water heater. By doing so, the manufacturing cost of the hot water supply device can be suppressed.

Since the present invention is characterized in that the detection values of the respective temperature sensors for water of the same temperature are compared, the detection values of not only water but also hot water of the same temperature may be compared. If several kinds of hot water having different temperatures are flowed to perform the same diagnosis, the number of diagnosis points is increased and the accuracy can be further improved. For example, when three or more temperature sensors are provided on the downstream side of the heat exchanger 16, the heat exchanger 1 can be operated by closing the bypass passage 8 and performing the hot water supply operation.
It is possible to diagnose a failure of the temperature sensor on the downstream side of 6.

Although the gas hot water supply apparatus shown in the above-mentioned embodiment is a single-function machine dedicated to hot water supply, even if it is a multi-function machine having a function of reheating the bath, the ignition mechanism for hot water supply is the same. Therefore, the present invention can be implemented.

[0035]

As described above, according to the present invention, since the output values of a plurality of three or more temperature sensors are compared to diagnose a failure, the following effects can be obtained. (1) Since the malfunctioning temperature sensor can be specified without accurately measuring the output value of each temperature sensor one by one, the repair work time can be shortened and the workability can be improved. (2) Since the diagnosis is performed through the CPU, the output value detected by the temperature sensor can be used for the diagnosis as it is, and it is not necessary to refer to a manual or the like. Therefore, the repair work time can be shortened and the workability can be improved. (3) Since the judgment is made through the CPU, the temperature sensor main body and the wiring can be diagnosed in one system, that is, in units of replacement parts. Therefore, the repair work time can be shortened and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a hot water supply device according to the present invention.

FIG. 2 is a flowchart for detecting a failure of a temperature sensor.

[Explanation of symbols]

 1 hot water supply device 2 water amount sensor S1, S2, S3 temperature sensor 6 water pipe 7 gas supply pipe 8 bypass passage 9 ignition device 10 burner 11 spark plug 12 insulator 13 flame rod 15 combustion fan 16 heat exchanger 17 original gas solenoid valve 18 gas proportional Valve 19 Water amount control valve 20 Mixing valve 22 Controller 22a CPU 23 Hot water tap 24 Memory 25, 26 Switching solenoid valve 27 Remote control device

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichiro Ito 2-13-7 Midori, Sumida-ku, Tokyo 1109 Urban Heights Ryogoku (72) Inventor, Masaru Ishimoto 2-11-2, Kajigaya, Takatsu-ku, Kawasaki-shi, Kanagawa Prefecture No. 222 (72) Inventor Satoshi Morita 6-9-5 Chuo, Ota-ku, Tokyo No. 24 Omori Dormitory

Claims (2)

[Claims] 1. A water pipe for introducing water from water supply and supplying heated water, a heat exchanger provided in the middle of the water pipe, a burner for heating the heat exchanger, and a burner for the burner. It has a gas supply pipe for supplying gas and three or more temperature detecting means provided for detecting the temperature in the water pipe, and determines the hot water supply temperature based on the temperature information output from the temperature detecting means. In the hot water supply device to be controlled, the temperature information output from each of the temperature detecting means based on the water having the same temperature is compared with the control means for flowing the water having the same temperature in the entire water pipe, and output from the other temperature detecting means. The hot water supply device is provided with a determining unit that determines that the temperature detecting unit that has output the temperature information whose difference from the temperature information exceeds a predetermined value is out of order. 2. A water pipe for introducing water from water supply and supplying heated water, a heat exchanger provided in the middle of the water pipe, a burner for heating the heat exchanger, and a burner for the burner. It has a gas supply pipe for supplying gas and three or more temperature detecting means provided for detecting the temperature in the water pipe, and determines the hot water supply temperature based on the temperature information output from the temperature detecting means. A method of detecting a failure of temperature detecting means of a hot water supply device, wherein water of the same temperature is flowed in the entire water pipe, and temperature information output from each of the temperature detecting means is compared based on water of the same temperature. A failure detecting method for a temperature detecting means of a hot water supply apparatus, which judges that the temperature detecting means that has output temperature information whose difference from the temperature information output from another temperature detecting means exceeds a predetermined value is out of order.