JPH01200146A - Method of detecting fault of hot water supplier - Google Patents

Abstract

PURPOSE:To make it possible to detect a fault of a relay circuit by judging a fault by a diagnosis function part of a microcomputer under such a condition that the temperature of hot water is not lowered after lapse of a predetermined time despite a fact that data for stopping generation of heat of heating elements are output. CONSTITUTION:In order to detect the fault of the hot water supplier, a diagnosis function part 20 detects a fault under such a condition that the temperature of hot water is not lowered even after the lapse of a predetermined time despite a fact that data relative to the stop of generation of heat of heating elements 5 are output from a temperature control function part 17. That is, the diagnosis function part 20 judges whether or not the temperature control function part 17 delivers data indicating the drive of the heating elements 5 to a relay circuit 12. When the data are not output to the circuit 12, the temperature of hot water at that time measured by a temperature sensor 8 is compared with the set temperature of hot water. As a result, if the temperature of hot water at that time is larger than the set hot water temperature, the relay contact of the relay circuit 12 is regarded as being welded, and the diagnosis function part 20 sends an alarm suggesting the contact welding of the relay thereby to notify the user of the same.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for detecting an abnormality in a hot water storage type water heater that always supplies hot water at a constant temperature by controlling a heating element included in the hot water storage tank. It is.

[Conventional technology]

FIG. 5 is a configuration diagram showing a conventional water heater.

In the figure, 1 is a hot water tank that always stores a certain amount of hot water.
2 is a water tap that supplies water to the hot water tank 1; 3 is a pole tap that is attached to the water tap 2 to keep the water level in the hot water tank 1 constant; and 4 is a water tap that supplies water to the hot water tank 1. an overflow pipe that discharges excess hot water to prevent the hot water storage tank 1 from overflowing when the water level cannot be maintained at a constant value;
6 is a temperature fuse connected in series to the electric heater 5, and 7 is an electric heater in the hot water tank 1 that supplies water from the faucet 2. 8 is a temperature sensor that outputs an electrical signal corresponding to the temperature of the hot water in the hot water storage tank 1 using, for example, a thermistor whose resistance value changes depending on the temperature; 9 is a temperature sensor that outputs an electric signal corresponding to the temperature of the hot water in the hot water storage tank 10 is a temperature control means for comparing the output signal of the temperature sensor 8 with a reference value to generate information for controlling the heat generation of the electric heater 5; 11 is a temperature control means for controlling the heat generation of the electric heater 5; Power supplied, 12
The operation of the 6th order relay circuit which operates according to the output information of the temperature control means 10 and controls the on/off of the power supply 11 supplied to the electric heater 5 will be explained.

First, the cock of the water tap 2 is opened and the hot water tank 1 is filled with water.

In that case, the water level in the hot water tank 1 rises and the pole tap 3
When it reaches a predetermined position, water supply from the faucet 2 is stopped due to its action. Even if the water supply is not stopped even if the water level exceeds a predetermined level for some reason, the excess water is discharged from the overflow pipe 4 and does not overflow from the hot water storage tank 1.

When the temperature control means 10 starts temperature control, since there is still water in the hot water tank 1, the electric signal from the temperature sensor 8 is much lower than the reference value, and the temperature control means 10 turns on the relay of the relay circuit 12. It outputs information to

Therefore, the power source 11 is supplied to the electric heater 5 via this output circuit 12.

The electric heater boils the water in the hot water storage tank 1. When the temperature of the hot water in the hot water storage tank 1 rises, the level of the electrical signal output by the temperature sensor 8 also rises, and when the water temperature rises to a predetermined value, the output of the temperature sensor 8 increases. The signal level also reaches the reference value. When the temperature control means 10 detects that the output signal of the temperature sensor 8 has reached the reference value.

Information for turning off the relay is output to the output circuit 12. Therefore, the power supply 11 supplied to the electric heater 5 via this output circuit 12 is cut off, and the electric heater 5 stops generating heat.

Here, when the cock of hot water faucet 9 is opened and hot water is used,
As the water level in the hot water storage tank 1 decreases, the pole tap 3 descends from a predetermined position, and water supply from the faucet 2 is started by this action. Since this supplied water has a low temperature, it lowers the temperature of the hot water stored in the hot water storage tank 1, and therefore the level of the electrical signal output from the temperature sensor 8 also decreases. When detecting that the level of the output signal of the temperature sensor 8 has become lower than the reference value, the temperature control means 10 outputs information to turn on the relay, and the relay circuit 12 turns on the power to the electric heater 5 based on this output information. 11 supply will be resumed. At this time, water from the faucet 2 is led to the vicinity of the electric heater 5 at the bottom of the hot water tank 1 by the water conduit 7 and is efficiently heated. As in the case described above, the supply of power 11 to electric heater 5 continues until the temperature of hot water in hot water storage tank 1 reaches a predetermined value and the level of the output signal of temperature sensor 8 reaches a reference value.

Further, even if the hot water in the Inn tank is not used, the same process as in the above case proceeds even if the hot water cools down after a long period of time, and the temperature of the hot water in the hot water storage tank 1 is maintained at a predetermined value.

[Problem to be solved by the invention]

Conventional water heaters are configured as described above, so to detect abnormalities such as relay welding in the output circuit that controls energization of the heating element, a current sensor is used to determine whether or not current is flowing directly to the heating element. This is done by doing this.

However, in this configuration, the current sensor and the signal from the current sensor are transmitted to a microcomputer (hereinafter referred to as "microcomputer").

A signal converter is required to convert the signal so that it can be processed by a microcomputer (referred to as a microcomputer), which poses problems of increased cost and space.

This invention was made to solve the above-mentioned problems, and by relying on software to detect abnormalities in the output circuit, it is possible to reduce costs and downsize the device. The purpose is to obtain a detection method.

[Means to solve the problem]

The abnormality detection method for a water heater according to the present invention is based on the condition that the hot water temperature does not decrease even after a certain period of time has elapsed despite the temperature control function unit outputting heat generation stop information of the heating element. This is considered abnormal.

[Effect]

The diagnostic function unit in this invention determines that there is an abnormality on the condition that the water temperature does not drop even after a certain period of time has passed even though the heating element heat generation stop information has been output. It is possible to detect abnormalities such as welding of relay contacts without depending on the system, making it possible to reduce costs and downsize the device.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water heater that implements the abnormality detection method of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a hot water tank, 2 is a water tap, 3 is a pole tap, 4 is an overflow pipe, 5 is an electric heater, 6 is a temperature fuse, 7 is a water pipe, 8 is a temperature sensor, 9 is a hot water tap, Reference numeral 12 denotes a relay circuit, which is the same as or corresponds to the conventional circuit shown in FIG.
Further, in FIG. 1, illustrations of ancillary circuits of the temperature sensor 8, a power source 11 for supplying the electric heater 5, etc. are also omitted.

14 is a hot water storage tank 1 for discharging all the stored hot water.
A drain pipe 15 is provided at the bottom of the drain pipe 14, and a thermal valve 16 is attached to the drain pipe 14 to control draining/stopping of the drain pipe 14.
is a thermal valve that is attached to the water faucet 2 in place of a cock to control the water supply/stop, and the relay circuit 1
In addition to the energization control of the electric heater 5, these thermal valves 15,
It is somewhat different from the conventional one in that it also performs 16 controls. Further, 17 is a temperature control function that generates information for controlling the heat generation of the electric heater 5 as a heating element based on the output signal of the temperature sensor 8; , a calendar function that outputs information such as days of the week, etc., and the calendar function 19 has first and second schedule tables 30 and 31 in which usage patterns of the water heater are preset, as shown in detail in FIG. an operation control function that controls operation/stop of the temperature control function 17 using information output from the calendar function 18 while referring to information set in both schedule tables; A diagnostic function 21 diagnoses abnormalities in the electric heater 5 and the output circuit 12 based on the output signal from the temperature sensor 8; 21 is a temperature control function 17; a calendar function 18; A microcomputer (hereinafter referred to as microcomputer) that realizes the operation control function 191 and the diagnostic function 20; 22 is an input circuit that converts the output signal of the temperature sensor 8 into information that can be processed by the microcomputer 21;
Reference numeral 4 denotes a man-machine interface using a console or the like for a user to input information to the microcomputer 21 and display output information from the microcomputer 21.

Next, the operation will be explained. Here, FIG. 3 is a flowchart showing the operation procedure of the operation control function 19. First, in step STI, it is checked whether today is the designated day for drainage. That is.

The operation control function 19 refers to the first schedule table 30 shown in FIG. 2(a), and determines whether the day of the week information sent from the calendar function 18 is Monday for which flag 1'' is set in the drainage column. If it is Monday, it is detected in step ST2 that the start time of wastewater treatment has arrived, and the wastewater treatment is executed in step ST3.

That is, in step ST2, the time information sent from the calendar function 18 is 4:30, the start time for wastewater treatment set in the wastewater column of the second schedule table 31 shown in FIG. 2(b). If it is detected that the time has passed, in step ST3, the operation control function 19 activates the relay circuit 12.
outputs information to control the relay, opens thermal valve 15 and closes 16.

As a result, the hot water (water) remaining in the hot water tank 1 is discharged from the drain pipe 14, and the hot water tank 1 becomes empty because water is no longer supplied from the faucet 2. Thereafter, when the end time "5:30" set in the drainage column of the second schedule table 31 is reached, the operation control function 19 starts this step ST.
3 completes the waste water treatment, sends information to the relay circuit 12, closes the thermal valve 15 and opens 16, therefore, the water tap 2
Water supply is started, and the hot water tank 1 is filled with water to the level where the pole tap 3 reaches a predetermined position.

Next, the day of the week information from the calendar function 18 is entered as a flag It in the temporary closure column of the first schedule table 30.
In step ST4, a check is made to see if the date falls on a day of temporary closure such as a public holiday, and if it is a day of temporary closure, then in step ST5, the column of temporary closure in the first schedule table 31 is checked. Set the corresponding flag to “0”
Clear it and finish driving for the day. If it is not a temporary holiday, in step ST6, a check is made as to whether or not the timer to be used is timer I based on the day of the week information, with reference to the first schedule table 30, and the timer I is checked based on the day of the week information. Flag set in the column It 17
1, if the day of the week information is Monday to Friday, the timer summer is selected in step ST7 and the process is executed in step 5TI.
Proceed to O. In other cases, it is checked in step ST8 whether the timer in use is timer ■, and based on the flag "1" set in the column of timer ■, if the day of the week information is Saturday, the timer is checked in step ST9. Select (2) to advance the process to step 5TIO, and if it is Sunday, the timer is not selected and the operation for that day is ended. In step 5 TIO, check whether the time information sent from the calendar function 18 has reached the start time set in the timer I column or the timer ■ column of the second schedule table 31, 6:30''. If it is detected that the start time has passed, the operation control function 19 outputs information instructing the temperature control function 17 to start temperature control in step 5T11, and starts the operation for that day. Start.

At this point, there is still water in the hot water tank 1, so the hot water temperature measured by the temperature sensor 8 is much lower than the set hot water temperature, and the output information from the input circuit 22 does not reach the reference value, so the temperature control Function 17 outputs information that turns on the relay of output circuit 12, drives electric heater 5 to boil water in hot water tank 1, and when the temperature of hot water in hot water tank 1 rises, temperature sensor 8
When the level of the electrical signal output by the input circuit 22 also increases and the output information of the input circuit 22 reaches the reference value, the temperature control function 17 outputs information to turn off the relay to the relay circuit 12, and the electric heater 5 starts supplying power. Cut off the fever to stop.

When it is detected that the temperature of the hot water stored in the hot water storage tank 1 has decreased by more than the differential width from the set hot water temperature based on information from the input circuit 22 that converted the output signal of the temperature sensor 8, the temperature control function 17 activates the relay. Information to turn it on is output, and the relay circuit 12 restarts power supply to the electric heater 5 based on this output information.

When the water temperature in the hot water storage tank 1 reaches the set water temperature, power is supplied to the electric heater 5 by the temperature control means 17 as in the case described above.
outputs information to the relay circuit 12 and stops power supply to the electric heater 5. This kind of temperature control is performed using calendar function 1.
Time information from 8.

During the period from Monday to Friday when timer 1 was selected, timer On Saturday, the process continues until the end time "12:30'" set in the timer column 2 of the second schedule table 31 is determined in step 5T12.

Here, the first and second schedule tables 30.3
The contents of item 1 are set using the keyboard of the man-machine interface 24 in accordance with the usage pattern of the water heater by the user.

Such temperature control is self-diagnosed by the diagnostic function section 20, and if an abnormality is detected, the user is notified by an alarm. FIG. 4 is a flowchart showing the operating procedure of this diagnostic function section 2o. At the start of the process, initial settings are first performed in step 5T21, and the relay welding detection counter CNT is cleared to "0".6 Next, in step 5T22, the temperature control function 17 instructs the electric heater 5 to be driven. It is determined whether information is being sent to the relay circuit 12.

As a result of the determination in step 5T22, if the temperature control function 17 has not outputted information instructing the drive of the electric heater 5 to the relay circuit 12, the process moves to step 5T23, and the relay contacts of the output circuit 12 are welded. Enter a routine that performs self-diagnosis.

In the relay welding self-diagnosis routine, first, step 5.
At T23, the counter CNT is incremented by 1, and at step 5T24, the current water temperature Pv measured by the temperature sensor 8 is set.
and the value obtained by subtracting 1°C from the set hot water temperature SP. As a result, if the hot water temperature Pv is greater, the process moves to step 5T25, and in step 5T25, it is confirmed that one hour has not elapsed since the counting start of the counter CNT, and the process returns to step 5T23. below.

If this process is repeated and the hot water temperature Pv does not drop below (SP-1) even if it is detected in step 5T25 that one hour has passed, it is assumed that the relay contacts of the relay circuit 12 are welded. The process proceeds to step 5T26, where the diagnostic function unit 20 sends an alarm suggesting welding of the relay contacts to the man-machine interface 24, and notifies the user using a buzzer, light-emitting display, or the like.

If the hot water temperature Pv has decreased by (SP-1) in Step 5T24 before Step 5T25 detects that one hour has elapsed, the process proceeds to Step 5T27, and the hot water temperature Pv and the standard hot water are Differential width Td from temperature SP
, that is, the hot water temperature (SP-T
d), and the process is returned to step 5T23 and repeated until the measured hot water temperature Pv becomes smaller. This is a process to eliminate the effect of a temporary drop in the temperature of the hot water when water is supplied from the faucet 2 into the hot water storage tank 1.

Only when the hot water temperature Pv becomes below (SP-Td).

It is determined that the relay of the relay circuit 12 is normal, and the process proceeds from step 5T27 to step 5T28, where the counter CNT stops counting, and the count value is cleared to "0" at step 5T29, and step 5T30 is executed. The process then returns to step 5T22.

The relay welding self-diagnosis routine includes step 5.
The process is repeatedly executed as appropriate until T30 detects the end of temperature control.

In the above embodiment, a thermal valve is used to prevent the water hammer phenomenon, but other electromagnetic valves may be used instead.

In addition, the fixed time for determining abnormality is determined by the capacity of the heating element.

Determined by the size of the hot water tank, heat radiation coefficient, etc.

In the embodiment described above, this fixed time is measured by counting up, but it can also be measured by counting down or by comparing the time when the routine is entered and the current time.

〔Effect of the invention〕

As described above, according to the present invention, the diagnostic function section included in the microcomputer determines that the water temperature does not drop even after a certain period of time has passed even though the heating element has output heat generation stop information. By determining that there is an abnormality, it is possible to detect an abnormality in the relay circuit without depending on the hardware, which has the effect of reducing costs and downsizing the device.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a water heater according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a schedule table, and FIG.
The figure is a flowchart showing the operation procedure of the operation control function section.
FIG. 4 is a flowchart showing the operating procedure of the diagnostic function section;
FIG. 5 is a configuration diagram showing a conventional water heater. 1 is a hot water storage tank, 5 is a heating element (electric heater), 8 is a temperature sensor, 12 is a relay circuit, 17 is a temperature control function section, 20 is a diagnostic function section, and 22 is an input circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant Yamatake Honeywell Co., Ltd. Figure 5

Claims (1)

[Claims] A hot water storage tank that stores hot water boiled by a heating element, a temperature sensor that measures the temperature of the hot water in the hot water storage tank, and information for controlling heat generation of the heating element based on an output signal of the temperature sensor. a temperature control function section, a relay circuit that opens and closes the energizing path of the heating body according to the output information of the temperature control function section, a calendar function that ticks time and outputs information such as date, time, day of the week, etc., and an output of the calendar function. In the hot water supply apparatus, the water heater has an operation control function that controls operation/stop of the temperature control function using information from the temperature control function, when a certain period of time has elapsed after the temperature control function unit outputs the information that the heating element stops generating heat. 1. A method for detecting an abnormality in a water heater, characterized in that when the temperature of the hot water does not decrease, a diagnostic function section determines that an abnormality has occurred in the relay circuit.