JP3485989B2 - Water heater - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater in which a gas burner heats a heat exchanger to obtain hot water having a predetermined temperature.

[0002]

2. Description of the Related Art In the above water heater, drainage such as combustion products adheres to the heat collecting fins of the heat exchanger after many years of use.
Therefore, if the space between the heat collecting fins is closed, the thermal efficiency is reduced. Therefore, in the conventional water heater, the thermal efficiency during combustion is calculated, and that value is compared with a preset reference value, and if it falls below the reference value, a maintenance alarm is issued or combustion is stopped. It has a combustion abnormality detection function. The reference value is calculated and set by the burner controller at the time of initial use, for example.

[0003]

However, in the above case, since it is a simple comparison of thermal efficiencies, an error occurs due to variations in appliances and kinds of gas (difference in calorific value), and a warning or a combustion is not always performed at an appropriate timing. Stopping is not performed, and problems such as so-called early disconnection and late disconnection occur. This may also be caused by an error in the thermal efficiency to be checked due to an error in the flow rate sensor or the like, an erroneous memory when replacing the burner controller, or an initial value being set to an inappropriate value. .

By the way, the thermal efficiency is lowered due to the clogging of the heat collecting fins of the heat exchanger as described above.
The difference in thermal efficiency varies depending on the output capacity.
That is, as shown in FIG. 7 (A), the thermal efficiency in the case of the minimum gas input is sharply decreased after the blockage rate of the heat collecting fins exceeds about 50% in the case of the maximum gas input. The tendency of decline is very small. Similarly, FIG.
Also in (B), even after the fin is clogged, the thermal efficiency is still close to the normal value on the minimum side of the gas input. That is, the thermal efficiency when the output capacity is small is not easily affected by the fin clogging.

[0005]

In view of the above, the present invention focuses on the difference in the thermal efficiency change due to the output capacity, and detects the combustion abnormality by checking the thermal efficiency without any error even if there is a difference in the equipment or the gas type. In order to be able to correspond accurately, the configuration is a thermal efficiency storage means for storing the thermal efficiency calculated at the time of small output capacity, and an abnormal value calculation means for setting an abnormal value from the stored value at a predetermined determination level, It is characterized in that a judging means for judging an abnormal operation by comparing the abnormal value with the arbitrarily calculated thermal efficiency is provided. Further, it is preferable that the judging means is provided with an alarm means for giving a notification before the arbitrarily calculated thermal efficiency reaches an abnormal value. Further, the time of the small output capacity can be the time of the minimum gas input.

[0006]

[Function] The thermal efficiency is calculated and stored as a reference value at the beginning of use of the device, so that an abnormal value is calculated based on a value obtained by removing differences in gas types, sensor variations, instrument variations, etc. Since it is judged whether or not there is an abnormality by comparing with the current thermal efficiency calculated in the above, there is little variation in the operation of each device, and the thermal efficiency for calculating this abnormal value is a small output with less influence of fin clogging etc. Since the thermal efficiency at the time of capacity is used as a standard, even when the burner controller is replaced and the standard value is stored again for repairs, the thermal efficiency as the standard is accurately calculated for each device, and an appropriate comparison and judgment are always made. Will be done. Further, when the judgment means is provided with the alarm means, it is possible to notify the combustion abnormality in advance, and it is possible to take an early action. Further, the reference thermal efficiency can be calculated more accurately when the low output capacity is set to the minimum gas input.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic view of a water heater, which includes a housing 1
A gas burner 3 and a heat exchanger 4 are provided in the combustion chamber 2 inside, and a water supply pipe 6 connected to the water supply is provided at an upstream side of a water passage pipe 5 passing through the inside of the heat exchanger 4, and a tap is provided at a downstream side. Hot water outlet pipes 8 provided with 7 are connected to each. The gas burner 3
Is provided with an ignition device (not shown), and a gas supply pipe 9 is connected to the gas supply pipe 9. From the upstream side, the main valve 10, the proportional control valve 11, and the main valve 12 are sequentially provided with three solenoid valves. It is provided. The water supply pipe 6 is provided with a water amount sensor 13 for detecting the amount of water, a temperature sensor 14 for detecting the incoming water temperature, and the tap water pipe 8 is provided with a temperature sensor 15 for detecting the tap water temperature. It is connected to the burner controller 20 to input the presence / absence of water flow, the incoming water temperature, and the outgoing hot water temperature, respectively. Further, the burner controller 20 can receive operation information of the remote controller 21 having a temperature setting knob for setting the hot water temperature,
Based on such information, the opening / closing operation of the main valve 10 and the main valve 12 and the adjusting operation of the proportional control valve 11 are performed. Reference numeral 16 is a warning buzzer. In the water heater thus configured, when water passes through the water supply pipe 6 by opening the faucet 7 attached to the hot water outlet pipe 8, the water amount sensor 13 detects the passage of the water and the burner controller 20 The burner controller 20 receives a water passage signal and outputs a combustion command signal to open the main valve 10 and the main valve 12 and to open the gas burner 3
Is to ignite.

The burner controller 20 receives the detection signal from the temperature sensor 15 while receiving the detection signal from the remote controller 21.
In addition to the temperature adjustment function that adjusts the proportional control valve 11 to match the outlet hot water temperature with the set temperature so that the outlet hot water temperature is set at, the current thermal efficiency from the outlet hot water temperature, incoming water temperature, water flow rate, gas input Is provided, and a combustion abnormality detection function is provided for performing processing such as warning and combustion stop when the calculated thermal efficiency is lower than the determination level by comparing it with the set determination level. FIG. 2 shows a block diagram of the burner controller 20.
Is a detection signal input from the temperature sensor 15 on the hot water outlet pipe 8 side, a temperature sensor 14 on the water supply pipe 6 side and a water amount sensor 13 respectively, and a detection signal from the current value measuring circuit of the proportional control valve 11 (gas. Input) and the thermal efficiency calculation unit for calculating the current thermal efficiency from 23, 23 is the thermal efficiency calculated by the thermal efficiency calculation unit 22 when the value is based on the minimum capacity of the device (here, the minimum gas input). The thermal efficiency storage unit 24 that stores the reference thermal efficiency is an abnormal value calculation unit that determines an abnormal value based on the stored reference thermal efficiency according to a predetermined determination level. In this determination level, in addition to the abnormal level determined to be abnormal here, a warning level for giving a warning before reaching the abnormal level is set.
As in (A), the values may be determined as a constant warning level (for example, 0.6) and an abnormal level (for example, 0.5) regardless of the output capability. Considering the tendency that the smaller one has less change in thermal efficiency,
As shown in FIG. 3B, the determination level on the minimum output capacity side is set to a higher level (for example, the warning level is 0.8 and the abnormal level is 0.
7) You can also do it. Therefore, for example, the reference thermal efficiency is 80
If the warning level is 0.8 and the abnormal level is 0.7 in%, 64% is the warning value and 56% is the abnormal value, respectively. The comparison unit 25, to which the current thermal efficiency calculated by the thermal efficiency calculation unit 22 is input, compares the thermal efficiency with the warning value and the abnormal value calculated by the abnormal value calculation unit 24, and the respective values are reached. If so, it issues a buzzer command to notify the combustion abnormality. Here, both levels are not alarms by the buzzer, but the warning level causes the buzzer command, and the abnormal level causes the solenoid valves of the main valve 10 and the main valve 12 to stop the energization of the solenoid valve to turn on the solenoid valve. The valve may be closed to stop the combustion, or different warning means (for example, a lamp at the warning level and a buzzer at the abnormal level) may be used for each of the warning level and the abnormal level.

Next, the combustion abnormality detecting function will be described with reference to a flowchart. In Fig. 4, first at the start,
In step 1 (hereinafter simply referred to as S1), it is determined whether or not the flow rate detected by the water amount sensor 13 by opening the faucet 7 is equal to or higher than a predetermined flow rate. If YES, the burner controller 20 is ignited in S2. Take control. Next, in S3, it is confirmed whether or not the reference thermal efficiency is stored, and if YES, combustion of the gas burner 3 is continued as it is, but if not stored, in S4, output is performed with the minimum capacity (for example, gas input 20% ), After confirming the stability of the tap water temperature in S5, the thermal efficiency calculation unit 22 calculates the reference thermal efficiency in S6,
The reference thermal efficiency is stored in S7, and the combustion is continued in S8. During the combustion of the gas burner, combustion abnormality detection for detecting clogging of the heat collecting fins of the heat exchanger 4 from a decrease in thermal efficiency is performed in S9. This operation is performed in S10 as shown in FIG. The abnormal value calculation unit 24 determines the warning value and the abnormal value from the reference thermal efficiency stored in. Next, in S11, the thermal efficiency calculation unit 22 calculates the current thermal efficiency, and in S12, the comparison unit 25 determines whether or not the current thermal efficiency has reached the abnormal value.
If YES, the buzzer 16 is notified in S13 that the heat collecting fin is clogged. If the abnormal value is not reached, the next S
The warning value is compared with 14 and if the warning value is reached, the buzzer 16 is similarly notified (S15). In the above S13, the buzzer 1 is judged by judging the clogging abnormality of the heat collecting fin.
Although the alarm is given by No. 6, the solenoid valve such as the main valve 10 is closed without the buzzer notification as described in the description of the burner controller 20, and the gas supply is cut off to stop the combustion. Good as a thing.

The calculation and storage of the reference thermal efficiency may be performed not at the time of ignition but at the initial stage of use of the device. That is, as shown in FIG. 6, if the reference thermal efficiency is not stored in the determination in S16, the output capacity is, for example, 20% in S17.
Whether or not the following is determined, and if YES, the reference thermal efficiency is calculated in S18 and stored in S19.
As described above, in the above-described embodiment, since the reference thermal efficiency is calculated and stored at the beginning of use of the device, the difference in gas type, the variation of the sensor, the abnormal value is calculated by removing the variation of the device, etc. The variation in the operation of each device is reduced. Furthermore, this reference thermal efficiency is calculated from the thermal efficiency at the time of small output capacity that is less affected by fin clogging,
Even if the burner controller is replaced and the reference value is re-stored for repair, etc., it can be obtained accurately for each instrument and compared, and the above processing can always be performed at appropriate timing without early or late disconnection. . In the above embodiment, if the thermal efficiency indexed during combustion does not reach an abnormal value, the warning value is compared and an alarm is issued.However, comparison with this warning value is omitted and only comparison judgment with an abnormal value is made. It is also possible to perform processing such as a buzzer alarm and combustion stop.

[0011]

As described above, according to the present invention, since the thermal efficiency is calculated and stored as a reference value at the beginning of use of the instrument, even if there is a difference in gas type or instrument, variation in sensor, etc., these are removed. An abnormal value is calculated based on the value and compared with the current thermal efficiency, and the variation in the operation of each device is reduced. Further, since the thermal efficiency for calculating the abnormal value is based on the thermal efficiency when the output power is small, which is less affected by fin clogging, even if the burner controller is replaced and the reference thermal efficiency is stored again for repairs, the value is the value of the appliance. It is accurately calculated for each. Therefore, there are no problems such as premature burnout and late burnout, and it is possible to detect combustion abnormality always at appropriate timing. Moreover, if an alarm means is provided before the abnormality judgment, it is possible to know the combustion abnormality in advance.
The reference thermal efficiency can be obtained more accurately when the minimum gas input is set to the low output capacity.

[Brief description of drawings]

FIG. 1 is a schematic view of a water heater.

FIG. 2 is a block diagram showing a combustion abnormality detection function of a burner controller.

FIG. 3A is a graph showing an example of a determination level. (B) is a graph showing an example of a determination level.

FIG. 4 is a flowchart of reference thermal efficiency storage performed after ignition of a water heater.

FIG. 5 is a flowchart of a combustion abnormality detection function.

FIG. 6 is a flowchart showing a case where reference thermal efficiency storage is performed by initial setting.

FIG. 7 (A) is a graph showing a change in thermal efficiency due to a difference in gas input. (B) is a graph showing a change in thermal efficiency after fin clogging.

[Explanation of symbols]

1 ... Housing, 2 ... Combustion chamber, 3 ... Gas burner,
4 ・ ・ Heat exchanger, 5 ・ ・ Water pipe, 6 ・ ・ Water pipe, 7 ・ ・
Faucet, 8 ・ ・ Hot water pipe, 9 ・ ・ Gas supply pipe, 10 ・ ・ Main valve, 11 ・ ・ Proportional control valve, 13 ・ ・ Water amount sensor, 14,
15 ・ ・ Temperature sensor, 16 ・ ・ Buzzer, 20 ・ ・ Burner controller

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F24H 1/10 F23N 5/02

Claims (3)

(57) [Claims] 1. A heat exchanger provided with a water supply pipe and a hot water discharge pipe, a gas burner for heating the heat exchanger, a hot water discharge temperature detecting means for detecting a temperature of hot water flowing through the hot water discharge pipe, and water flowing through the hot water supply pipe. Water supply temperature detection means for detecting temperature, flow rate detection means for detecting the amount of water flowing through the water supply pipe or hot water flowing through the hot water supply pipe, gas amount control means for controlling the amount of gas supplied to the gas burner, and the hot water discharge In a water heater equipped with a temperature detecting means, a water supply temperature detecting means, a thermal efficiency calculating means for calculating a thermal efficiency based on each detection signal from the flow rate detecting means and a control signal for gas amount control, the water heater is operated at a small output capacity. The thermal efficiency storing means for storing the thermal efficiency, the abnormal value calculating means for setting the abnormal value from the stored value at a predetermined judgment level, and the abnormal value and the arbitrarily calculated thermal efficiency are compared to judge the operation abnormality. You Water heater, characterized in that a determining means. 2. The water heater according to claim 1, wherein the determination means includes an alarm means for giving an alarm before the arbitrarily calculated thermal efficiency reaches an abnormal value. 3. The water heater according to claim 1, wherein the low output capacity is the minimum gas input.