Method for detecting scale on electric heater, device for detecting scale on electric heater, and electric boiler

Abstract

To provide a method for detecting scale on an electric heater, a device for detecting scale on an electric heater, and an electric boiler that can detect scale adhesion on an electric heater without using a temperature sensor.SOLUTION: A current value of a current flowing through a heater wire is measured, and when the voltage value of a voltage applied to the heater wire and the resistance value of the heater wire based on the measured current value exceed a set threshold, scale adhesion to the electric heater is detected.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for detecting scale in an electric heater, a scale detection device for an electric heater, and an electric boiler. [Background technology]

[0002] Patent Document 1 describes an electric boiler that includes a water pipe, an electric heater placed inside the water pipe, and a temperature sensor placed in the heat-generating area on the surface of the electric heater, and that can manage the temperature of the electric heater.

[0003] Patent Document 2 describes a steam oxide scale removal method and apparatus that can easily remove steam oxide scale that is densely adhered to metal surfaces in a short time without the need for wastewater treatment such as COD (Chemical Oxygen Demand) treatment.

[0004] Patent document 3 describes an electric boiler that includes a water pipe, an electric heater placed inside the water pipe, a water supply means for supplying water to the water pipe so that the water level in the water pipe is maintained within a predetermined water level range, and a control device, and that is capable of detecting the occurrence of abnormalities early on. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-086222 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-005596 [Patent Document 3] Japanese Patent Publication No. 2020-041708 Summary of the Invention [Problem to be solved by the invention]

[0006] Electric heaters used as heat sources for electric boilers have a problem in that scale builds up on their surfaces over time, reducing their heat transfer efficiency. As a result, the electric heaters can overheat abnormally, increasing the risk of damage to the heaters.

[0007] To solve this problem, it is conceivable to detect the deposition of scale on the electric heater by placing a temperature sensor near the surface of the electric heater and detecting abnormal overheating of the electric heater.

[0008] However, when using a temperature sensor to detect scale buildup on an electric heater, there is a risk that scale buildup on the electric heater cannot be accurately detected due to misalignment of the temperature sensor relative to the electric heater or scale buildup on the surface of the temperature sensor.

[0009] An object of the present disclosure is to provide a method for detecting scale on an electric heater, a scale detection device for an electric heater, and an electric boiler that are capable of detecting scale adhesion to an electric heater without using a temperature sensor. [Means for solving the problem]

[0010] The scale detection method for an electric heater disclosed herein is a method for detecting scale on an electric heater in an electric boiler that includes a water storage section, an electric heater that is equipped with a heater wire that generates heat when an electric current flows through it and is arranged inside the water storage section, and a heater drive section that applies a voltage to the heater wire to drive the electric heater, and measures the current value of the current flowing through the heater wire, and detects the adhesion of scale to the electric heater when the voltage value of the voltage applied to the heater wire and the resistance value of the heater wire based on the measured current value exceed a set threshold.

[0011] In the method for detecting scale on an electric heater according to the present disclosure, when adhesion of scale to the electric heater is detected, a user may be notified of the adhesion of scale to the electric heater.

[0012] The threshold value may be a value determined based on the maximum resistance value of the heater wire when the electric heater is operated without any scale.

[0013] The threshold value may be a value determined based on the resistance value of the heater wire at maximum output of the electric heater when the electric heater is operated without any scale.

[0014] The scale detection device for an electric heater disclosed herein is a scale detection device for an electric heater used in an electric boiler that includes a water storage section, an electric heater that includes a heater wire that generates heat when an electric current flows through it and is arranged inside the water storage section, and a heater drive section that applies a voltage to the heater wire to drive the electric heater, and is equipped with a scale detection section that detects the adhesion of scale to the electric heater when the resistance value of the heater wire, which is based on the voltage value of the voltage applied to the heater wire and the current value of the current flowing through the heater wire, exceeds a set threshold.

[0015] The electric boiler disclosed herein comprises a water storage section, an electric heater disposed inside the water storage section and having a heater wire that generates heat when an electric current flows through it, a heater drive section that applies a voltage to the heater wire to drive the electric heater, a measurement section that measures the current value of the current flowing through the heater wire, and a scale detection section that detects the adhesion of scale to the electric heater when the resistance value of the heater wire, based on the voltage value of the voltage applied to the heater wire and the current value measured by the measurement section, exceeds a set threshold value. [Effects of the Invention]

[0016] According to the scale detection method for an electric heater, the scale detection device for an electric heater, and the electric boiler disclosed herein, it is possible to detect the adhesion of scale to an electric heater without using a temperature sensor. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing a schematic configuration of an electric boiler according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of the electric heater and its surroundings in the electric boiler. [Figure 3] 4 is a flowchart showing a process flow when detecting scale in the electric boiler. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of an electric heater and its surroundings in a modified example of the electric boiler. [Figure 5] FIG. 4 is a diagram showing a schematic configuration of an electric boiler according to a second embodiment of the present disclosure. [Figure 6] FIG. 2 is a diagram showing a schematic configuration of the electric heater and its surroundings in the electric boiler. [Figure 7] FIG. 10 is a diagram showing a schematic configuration of an electric heater and its surroundings in a modified example of the electric boiler. DETAILED DESCRIPTION OF THE INVENTION

[0018] [First embodiment] Next, embodiments of the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of an electric boiler 1 according to a first embodiment of the present disclosure. Fig. 2 is a diagram showing a schematic configuration of the periphery of an electric heater 11 in the electric boiler 1.

[0019] As shown in Figures 1 and 2, the electric boiler 1 of this embodiment is, for example, a round steam boiler, and includes a water storage section 10, an electric heater 11, a heater driving section 12, a water level sensor 13, a water supply amount adjusting section 14, an air-water separator 15, a pressure gauge 16, a control section 17, and a notification section 18.

[0020] The water storage unit 10 is a cylindrical can capable of storing water therein.

[0021] The electric heater 11 is disposed inside the water storage section 10 and heats the water stored in the water storage section 10. The electric heater 11 includes a heater wire 20 that generates heat when an electric current flows through it, and a cover 11a that covers the heater wire 20.

[0022] The electric heater 11 is not limited to one having a cover 11a that covers the heater wire 20, but may be one that does not have a cover 11a and in which the heater wire 20 is exposed to the outside.

[0023] The heater wire 20 is connected to the heater driving unit 12, and generates heat due to the current that flows when a voltage is applied by the heater driving unit 12, thereby heating the surface of the electric heater 11. An ammeter 21 is also connected in series to the heater wire 20. The ammeter 21 is an example of a measuring unit in the technology of the present disclosure, and measures the current value of the current that flows through the heater wire 20.

[0024] Returning to Figure 1, heater driving unit 12 applies a voltage to heater wire 20 to drive electric heater 11. Water level sensor 13 measures the level of water stored in water storage unit 10. Water supply amount adjustment unit 14 includes a water supply valve and a water supply pump, and adjusts the amount of water supplied to water storage unit 10 under the control of control unit 17.

[0025] The water-air separator 15 separates the liquid portion from the water-air mixed vapor discharged from the water storage unit 10 and supplies only the gas portion to the outside. The water-air separator 15 is provided with a valve (not shown) that adjusts the amount of steam supplied. The liquid portion, i.e., water, separated by the water-air separator 15 is supplied to the water storage unit 10.

[0026] The pressure gauge 16 measures the pressure of the steam mixture discharged from the water reservoir 10 .

[0027] The control unit 17 controls the overall operation of the electric boiler 1. The control unit 17 also functions as a scale detection unit that detects the adhesion of scale to the electric heater 11.

[0028] The control unit 17 includes a processor 17a, a memory 17b, and a storage unit 17c. The processor 17a executes predetermined processing based on a control program stored in the memory 17b. The storage unit 17c is configured, for example, with a hard disk drive (HDD) or a solid state drive (SSD), and stores required software and data.

[0029] When the control unit 17 detects the adhesion of scale to the electric heater 11, the notification unit 18 notifies the user of the adhesion of scale to the electric heater 11. The notification unit 18 may be any device capable of notifying the user of the adhesion of scale, such as an LED (Light Emitting Diode) indicator, a message display on a monitor, or the pronunciation of a notification sound or message by a speaker.

[0030] Next, the operation of the electric boiler 1 will be described. First, a series of operations from start-up to shut-down of the electric boiler 1 will be described.

[0031] The following operations are performed by the control unit 17, which performs integrated control of the heater driving unit 12 and the supply water amount adjusting unit 14 based on the measurement values ​​of the water level sensor 13 and the pressure gauge 16.

[0032] First, upon receiving a start-up instruction from the user, control unit 17 stores water in water storage unit 10 up to a specified amount.

[0033] Next, the control unit 17 drives the electric heater 11 to heat the water in the water storage unit 10 as an initial heating.

[0034] When the pressure of the steam mixture reaches the set value, the control unit 17 performs steady-state heating by reducing the output of the electric heater 11 to a level lower than that during initial heating, and adjusts the output of the electric heater 11 so that the pressure of the steam mixture falls within a certain range.

[0035] In addition, the control unit 17 follows the fluctuation of the water level in the water storage unit 10 due to the supply of steam from the steam separator 15, and instructs the supply of water to the water storage unit 10 and the heating of the water in the water storage unit 10.

[0036] Finally, the control unit 17 receives a shutdown instruction from the user and stops the operation of the electric boiler 1.

[0037] However, the electric heater 11 has a problem in that the heat transfer efficiency decreases as scale accumulates on the surface over time, which results in the electric heater 11 overheating abnormally, increasing the risk of damage to the electric heater 11.

[0038] For this reason, it is conceivable to detect the buildup of scale on the electric heater 11 by placing a temperature sensor near the surface of the electric heater 11 and detecting abnormal overheating of the electric heater 11. However, when using a temperature sensor to detect the buildup of scale on the electric heater 11, there is a risk that the buildup of scale on the electric heater 11 cannot be accurately detected due to misalignment of the temperature sensor with respect to the electric heater 11 or buildup of scale on the surface of the temperature sensor.

[0039] Taking these circumstances into consideration, the electric boiler 1 of this embodiment is configured to be able to detect the adhesion of scale to the electric heater 11 without using a temperature sensor.

[0040] The resistance value of the heater wire 20 provided in the electric heater 11 has a characteristic that increases as the temperature rises.

[0041] Therefore, when the resistance value of the heater wire 20 based on the voltage value of the voltage applied to the heater wire 20 and the current value of the current flowing through the heater wire 20 exceeds a set threshold value, i.e., when the temperature of the heater wire 20 becomes higher than expected, the control unit 17 determines that abnormal overheating due to scale has occurred and detects the adhesion of scale to the electric heater 11.

[0042] The resistance value R of the heater wire 20 can be calculated by the following formula (1). R=V / I (1) however, R: Resistance value of heater wire 20 V: voltage value of the voltage applied to the heater wire 20 I: Current value of the current flowing through the heater wire 20

[0043] The voltage value V of the voltage applied to the heater wire 20 is known because it is the voltage value applied by the heater driving unit 12 based on the control of the control unit 17. The current value I of the current flowing through the heater wire 20 is the current value measured by the ammeter 21.

[0044] Next, the detailed process of detecting adhesion of scale to the electric heater 11 by the control unit 17 will be described.

[0045] The control unit 17 uses a preset threshold value for the resistance value as reference data, and the resistance value of the heater wire 20 when the electric boiler 1 is in operation as operation data, and detects the adhesion of scale to the electric heater 11 by comparing the reference data with the operation data. The reference data is registered in a memory unit (not shown) in the control unit 17.

[0046] Regarding the reference data, for example, in aspect 1, in an electric boiler 1 equipped with an electric heater 11 that is not covered with scale, the reference data may be a value determined based on the maximum resistance value of the heater wire 20 during a single operation of the electric boiler 1, i.e., during a series of operations from starting up to shutting down the electric boiler 1.

[0047] Here, the "value determined based on the maximum resistance value of the heater wire 20" may be the maximum resistance value of the heater wire 20 itself, or a value converted by substituting the maximum resistance value of the heater wire 20 into a predetermined conversion formula. For example, the reference data may be a value between +5% and +10% of the maximum resistance value of the heater wire 20 to prevent erroneous detection of scale. Alternatively, the reference data may be a value between +1% and +5% of the maximum resistance value of the heater wire 20 to more accurately detect scale while preventing erroneous detection of scale.

[0048] When the water temperature around the electric heater 11 is high, as during steady-state heating, the resistance value of the heater wire 20 may become high even if the output of the electric heater 11 is not at its maximum. Therefore, by using the reference data of aspect 1, it is possible to detect the adhesion of scale to the electric heater 11 not only during initial heating when the output of the electric heater 11 is at its maximum, but also during steady-state heating.

[0049] Furthermore, as for the reference data, in aspect 2, in an electric boiler 1 equipped with an electric heater 11 that is not covered with scale, the reference data may be a value determined based on the resistance value of the heater wire 20 at the maximum output of the electric heater 11 that is set during operation of the electric boiler 1.

[0050] Here, the "value determined based on the resistance value of the heater wire 20 at maximum output" may be the resistance value of the heater wire 20 at maximum output itself, or a value converted by substituting the resistance value of the heater wire 20 at maximum output into a predetermined conversion formula. For example, in order to prevent erroneous detection of scale, the reference data may be a value between +5% and +10% of the resistance value of the heater wire 20 at maximum output. Furthermore, in order to detect scale more precisely while preventing erroneous detection of scale, the reference data may be a value between +1% and +5% of the resistance value of the heater wire 20 at maximum output.

[0051] By using the reference data of the second aspect, it is possible to detect the adhesion of scale to the electric heater 11, particularly during the initial heating when the output of the electric heater 11 is at its maximum.

[0052] When comparing the reference data and operational data using the reference data of aspect 2, it is preferable to compare data under the same conditions of the output of the electric heater 11 and the pressure of the steam mixture, such as when the output of the electric heater 11 is 100% and the pressure of the steam mixture is 0.9 MPa. The pressure of the steam mixture corresponds to the water temperature in the water storage section 10. This makes it possible to prevent a decrease in scale detection accuracy due to disturbances such as the influence of the ambient temperature.

[0053] Furthermore, in addition to the data on the resistance value of the heater wire 20 when the electric heater 11 is at maximum output and at a specific pressure of the air-water mixed steam, multiple pieces of data on the resistance value of the heater wire 20 when the electric heater 11 is at a pressure other than the maximum output and at a known pressure of the air-water mixed steam may be obtained to obtain performance curve data of the electric heater 11, and this performance curve data may be used as the reference data.

[0054] The reference data of aspect 1 and aspect 2 may be determined from data acquired through a single operation, or may be determined from a representative value of multiple data acquired through multiple operations. The representative value of the multiple data may be any value that indicates the tendency of the multiple data, such as an average value or a median value.

[0055] Furthermore, both the reference data of the first aspect and the reference data of the second aspect may be registered in the control unit 17, or only one of them may be registered in the control unit 17.

[0056] The reference data may be acquired by incorporating a new electric heater 11 into each individual electric boiler 1 during manufacturing and performing a trial operation, and the acquired reference data may then be registered in the control unit 17. Alternatively, reference data that has been acquired in advance for a common model may be registered in the control unit 17.

[0057] Furthermore, the control unit 17 may be configured to make the notification unit 18 give notifications in stages. Here, as an example, a mode in which the color of the LED indicator is changed in stages will be described.

[0058] When the notification unit 18 performs notification in stages, a value lower than the threshold value of the reference data may be set as the threshold value for displaying an early warning based on the threshold value of the reference data. Here, as an example, a value that is 90% of the threshold value of the reference data is set as the first reference data, and the threshold value of the reference data is set as the second reference data.

[0059] Next, the flow of processing when detecting scale will be described with reference to the flowchart of FIG.

[0060] First, the control unit 17 starts up the electric boiler 1 in step S1.

[0061] Next, in step S2, the control unit 17 acquires operation time data.

[0062] Next, in step S3, the control unit 17 compares the operation data with the first reference data.

[0063] If it is determined in step S3 that the operational data is within the threshold value of the first reference data, the control unit 17 displays a blue indicator in step S4, and the process proceeds to step S2.

[0064] If it is determined in step S3 that the operational data exceeds the threshold of the first reference data, i.e., if it is determined that the operational data is outside the threshold of the first reference data, the control unit 17 performs a comparison determination between the operational data and the second reference data in step S5.

[0065] If it is determined in step S5 that the operational data is within the threshold value of the second reference data, the control unit 17 displays a yellow indicator in step S6 and proceeds to step S2.

[0066] If it is determined in step S5 that the operational data exceeds the threshold of the second reference data, that is, if it is determined that the operational data is outside the threshold of the second reference data, the control unit 17 displays a red indicator in step S7 and transitions to step S2.

[0067] As described above, according to the electric boiler 1 of this embodiment, it is possible to detect the adhesion of scale to the electric heater 11 without using a temperature sensor.

[0068] In the electric boiler 1 of this embodiment, the voltage value V of the voltage applied to the heater wire 20 is the voltage value applied by the heater driving unit 12 under the control of the control unit 17. However, as shown in Fig. 4, a voltmeter 22 may be connected in parallel to both ends of the heater wire 20, and the voltage value measured by the voltmeter 22 may be used. In this way, by using the voltmeter 22 to check the effective voltage applied to the heater wire 20, the accuracy of scale detection can be improved.

[0069] [Second embodiment] Next, a second embodiment of the present disclosure will be described. In the second embodiment, a scale detection device 30 that detects the adhesion of scale to the electric heater 11 is retrofitted to an electric boiler 2 that does not have a function for detecting the adhesion of scale to the electric heater 11. Fig. 5 is a diagram showing a schematic configuration of the electric boiler 2 of the second embodiment of the present disclosure. Fig. 6 is a diagram showing a schematic configuration of the periphery of the electric heater 11 in the electric boiler 2.

[0070] The electric boiler 2 of the second embodiment differs from the electric boiler 1 of the first embodiment in that the control unit 17 does not function as a scale detection unit, and a scale detection device 30 that detects the adhesion of scale to the electric heater 11 is separately connected, as shown in Figure 5.

[0071] In the electric boiler 2 of this embodiment, the same components as those in the electric boiler 1 of the first embodiment are given the same reference numerals, and explanations thereof will be omitted unless particularly necessary. Furthermore, the process of detecting scale adhesion to the electric heater 11 in the scale detection device 30 is basically the same as the detection process in the control unit 17 of the electric boiler 1 of the first embodiment, and therefore detailed explanations other than those of the differences will be omitted.

[0072] 6, the scale detection device 30 includes a processor 30a, a memory 30b, a storage unit 30c, and a notification unit 30d. The processor 30a functions as a control unit that controls the overall operation of the scale detection device 30, and as a scale detection unit that detects the adhesion of scale to the electric heater 11. The processor 30a executes predetermined processing based on a control program stored in the memory 30b. The storage unit 30c is configured, for example, by an HDD or SSD, and stores required software and data.

[0073] When the scale detection device 30 (more specifically, the processor 30a) detects the adhesion of scale to the electric heater 11, the notification unit 30d notifies the user of the adhesion of scale to the electric heater 11. The notification unit 30d may be any device capable of notifying the user of the adhesion of scale, such as an LED indicator, a message displayed on a monitor, or a notification sound or message emitted by a speaker.

[0074] The scale detection device 30 of this embodiment determines that abnormal overheating due to scale has occurred when the resistance value of the heater wire 20, which is based on the voltage value of the voltage applied to the heater wire 20 and the current value of the current flowing through the heater wire 20, exceeds a set threshold value, i.e., when the temperature of the heater wire 20 becomes higher than expected, and detects the adhesion of scale to the electric heater 11.

[0075] The resistance value R of the heater wire 20 can be calculated by the following formula (1), similarly to the control unit 17 of the electric boiler 1 of the first embodiment. R=V / I (1) however, R: Resistance value of heater wire 20 V: voltage value of the voltage applied to the heater wire 20 I: Current value of the current flowing through the heater wire 20

[0076] The voltage value V of the voltage applied to the heater wire 20 is known because it is the voltage value applied by the heater driving unit 12 based on the control of the control unit 17. The current value I of the current flowing through the heater wire 20 is the current value measured by the ammeter 21.

[0077] The scale detection device 30 obtains the voltage value V of the voltage applied by the heater driving unit 12 from the control unit 17 and obtains the current value I from the ammeter 21 to detect the adhesion of scale to the electric heater 11.

[0078] When the scale detection device 30 detects adhesion of scale to the electric heater 11, the notification unit 30d notifies the user of the adhesion of scale to the electric heater 11.

[0079] In the scale detection device 30 of this embodiment, the voltage value V of the voltage applied to the heater wire 20 is the voltage value applied by the heater driving unit 12 under the control of the control unit 17. However, as shown in Fig. 7, a voltmeter 22 may be connected in parallel to both ends of the heater wire 20, and the voltage value measured by the voltmeter 22 may be used. In this way, by using the voltmeter 22 to check the effective voltage applied to the heater wire 20, the accuracy of scale detection can be improved.

[0080] In addition, the scale detection device 30 may not have a notification unit 30d, and when it detects scale adhesion to the electric heater 11, it may notify the control unit 17 of the electric boiler 2, and the notification unit 18 provided in the electric boiler 2 may notify the user of the scale adhesion to the electric heater 11.

[0081] [Variations] Although the embodiments of the present disclosure have been described above, the technology of the present disclosure is not limited to the above embodiments and can be modified as appropriate.

[0082] For example, in the above formula (1), when the voltage value V of the voltage applied to the heater wire 20 is known, there is a correlation between the current value I of the current flowing through the heater wire 20 and the resistance value R of the heater wire 20.

[0083] Therefore, in detecting the deposition of scale on the electric heater 11 due to the resistance value of the heater wire 20 exceeding a set threshold value, instead of calculating the resistance value R of the heater wire 20 as described above and directly comparing the calculated resistance value R with the threshold value for the resistance value, it is also possible to set a threshold value for the current value corresponding to the threshold value for the resistance value without calculating the resistance value R of the heater wire 20, and to indirectly compare the current value I with the threshold value for the current value.

[0084] Furthermore, the type of electric boiler is not limited to the steam boiler described above, but may be other types of boilers such as a hot water boiler.

[0085] Furthermore, the shape of the boiler is not limited to the above-mentioned round boiler, but may be other types of boilers, such as a water tube boiler.

[0086] In addition to the above, appropriate changes may be made to the above-described and illustrated contents, such as deleting unnecessary parts, adding new elements, or substituting elements, within the scope of the gist of the technology of the present disclosure. [Explanation of symbols]

[0087] 1. Electric boiler 10 Water storage section 11 Electric heater 12 Heater drive unit 13 Water level sensor 14 Supply water amount adjustment section 15 Air-water separation section 16 Pressure gauge 17 Control Unit 17a processor 17b memory 17c storage section 18 Notification Department 20 Heater wire 21 Ammeter 22 Voltmeter 30 Scale detection device 30a processor 30b memory 30c storage section 30d notification section

Claims

1. A water reservoir; an electric heater provided inside the water storage section, the electric heater having a heater wire that generates heat when an electric current flows therethrough; a heater driving unit that applies a voltage to the heater wire to drive the electric heater, measuring the current value of the current flowing through the heater wire; When the resistance value of the heater wire based on the voltage value of the voltage applied to the heater wire and the measured current value exceeds a set threshold, the deposition of scale on the electric heater is detected. How to detect scale on an electric heater.

2. When adhesion of scale to the electric heater is detected, the user is notified of the adhesion of scale to the electric heater. The method for detecting scale on an electric heater according to claim 1.

3. The threshold value is a value determined based on the maximum resistance value of the heater wire when the electric heater is operated without scale. The method for detecting scale on an electric heater according to claim 1 or 2.

4. The threshold value is a value determined based on the resistance value of the heater wire at the maximum output of the electric heater when the electric heater is operated without any scale. The method for detecting scale on an electric heater according to claim 1 or 2.

5. A water reservoir; an electric heater provided inside the water storage section, the electric heater having a heater wire that generates heat when an electric current flows therethrough; a heater driving unit that applies a voltage to the heater wire to drive the electric heater, A scale detection unit is provided that detects the deposition of scale on the electric heater when the resistance value of the heater wire based on the voltage value of the voltage applied to the heater wire and the current value of the current flowing through the heater wire exceeds a set threshold. Scale detection device for electric heaters.

6. A water reservoir; an electric heater provided inside the water storage section, the electric heater having a heater wire that generates heat when an electric current flows therethrough; a heater driving unit that applies a voltage to the heater wire to drive the electric heater; a measuring unit for measuring a current value of a current flowing through the heater wire; a scale detection unit that detects adhesion of scale to the electric heater when a resistance value of the heater wire based on a voltage value of the voltage applied to the heater wire and a current value measured by the measurement unit exceeds a set threshold value. Electric boiler.

Images