JP4078751B2 - Combustion control method for water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion control method for a water heater.
[0002]
[Prior art]
Conventionally, in a water heater having a simple self-diagnosis function, a difference between a target number and a real number is detected, and when the difference reaches a certain level, a safe operation is performed and operation is stopped.
Moreover, in the water heater with a CO sensor, when the detected CO density | concentration reaches a fixed value, the control method of operating an instrument safely was taken.
In another water heater with a CO sensor, a control method is adopted in which when the detected CO concentration reaches a certain value, the rotation speed of the air supply fan is increased, and when the CO concentration further increases, the appliance is operated safely. .
[0003]
[Problems to be solved by the invention]
However, in the first conventional water heater shown above, the cause of the difference between the target number and the actual number is not one type, but there are two types according to the cause. All actions were taken without any action.
The second conventional water heater shown above has a problem in that no combustion abnormality other than incomplete combustion by the CO sensor cannot be detected.
In the third conventional water heater shown above, there is a problem that it cannot be determined whether the cause of the increase in CO concentration is due to air shortage due to supply / exhaust blockage or due to a decrease in oxygen concentration in the air. Had.
[0004]
Therefore, the present invention eliminates the above-mentioned disadvantages of the conventional water heater and accurately determines the state of incomplete combustion, insufficient fuel supply, poor transfer, and low oxygen concentration in the surrounding environment, and promptly copes with it. Therefore, an object is to provide a combustion control method for a water heater that can ensure a good combustion state.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a combustion control method for a hot water heater according to the present invention generates a burner for burning fuel gas, an air supply fan for supplying air to combustion of the burner, and water for hot water supply by the combustion. A method for controlling combustion of a hot water heater comprising at least a heat exchanger that is heated by heat to make hot water, a CO sensor that detects the CO concentration of exhaust gas, a controller that controls the entire mechanism, and a remote controller, wherein the burner is burning When the difference obtained by subtracting the actual combustion heat amount from the set target combustion heat amount is equal to or greater than a certain reference heat amount difference , is the CO concentration of the exhaust gas at that time further equal to or greater than the certain reference CO concentration? determines whether, if the CO concentration is equal to or greater than a fixed reference CO concentration increases the rotational speed of the air supply fan, the fuel of the CO concentration to the burner in the case below a certain reference CO concentration To control so as to increase the feeding amount is set to the first feature.
Combustion control method for a water heater of the present invention or the burner performs combustion of the fuel gas or the like, air supply fan for supplying air to the combustion of the burner, the water for hot water supply and heating in the heat generated by the combustion A hot water combustion control method comprising at least a heat exchanger for warm water, a CO sensor for detecting the CO concentration of exhaust gas, a controller for controlling the entire mechanism, and a remote controller, wherein the target combustion heat amount during combustion of the burner If the difference obtained by subtracting the actual air volume from the target air volume set corresponding to the above becomes a certain reference air volume difference or not, whether the CO concentration of the exhaust gas at that time is more than a certain standard CO concentration If the CO concentration is equal to or higher than a certain reference concentration, the rotation speed of the supply air fan is increased. If the CO concentration is less than the certain reference CO concentration, the rotation of the supply air fan is temporarily performed. Number And a second control means controls so as to made.
[0006]
According to the first feature, during the combustion operation, if the actual combustion heat quantity is lower than the target combustion heat quantity by the reference heat quantity or more, is the CO concentration of the exhaust gas more than a certain reference CO concentration? It is determined whether or not, and when the reference CO concentration is equal to or higher than the reference CO concentration, the rotational speed of the air supply fan is increased. This is because it is determined that the reason why the actual combustion heat quantity is low is due to incomplete combustion caused by the closed state of the supply / exhaust portion. On the other hand, when the actual combustion heat quantity is low but the CO concentration is not higher than the reference CO concentration, the fuel supply amount is increased. This is because it is determined that the actual combustion heat quantity is low, that the combustion specification is abnormal, that is, the fuel supply to the burner is insufficient.
In other words, according to the first feature, when the actual combustion heat quantity is insufficient with respect to the target combustion heat quantity, the CO concentration of the exhaust gas is determined to determine whether the cause is incomplete combustion or the fuel supply quantity. It is possible to determine whether this is due to a shortage of fuel, and if this does not sufficiently increase the output of the actual combustion amount, it is possible to ensure appropriate combustion by taking appropriate measures and adjustments according to the cause It became.
[0007]
Further, according to the second feature, when the actual air volume becomes lower than the target air volume by the reference air volume during the combustion operation, whether or not the CO concentration of the exhaust gas is more than a certain reference CO concentration. Is determined, and if it is equal to or higher than the reference CO concentration, the rotational speed of the air supply fan is increased. This is because the reason why the actual air volume is low is due to the closed state of the air supply / exhaust part, etc., and it is determined that the combustion is incomplete. On the other hand, when the actual air volume is low but the CO concentration is not higher than the reference CO concentration, the rotational speed of the air supply fan is once reduced. In this case, the reason why the CO concentration is low is due to fire transfer failure, which is based on the fact that it is determined that combustion is not sufficiently performed in the entire burner. Therefore, once the air volume is lowered, the fire transfer in the burner is promoted.
That is, according to the second feature, the difference between the target air flow rate and the actual air flow rate and the CO concentration are determined in relation to the reference values, respectively, so that the cause of combustion failure is due to incomplete combustion or burner failure of the burner. It was possible to determine whether or not it was caused by this, and it was possible to ensure appropriate combustion by taking appropriate measures and adjustments according to the causes.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram of a water heater that realizes the method of the present invention, FIG. 2 is a control flowchart showing a first embodiment of the method of the present invention, and FIG. 3 is a control flowchart showing a second embodiment of the method of the present invention. FIG. 4 is a control flowchart showing a third embodiment of the method of the present invention.
[0010]
First, in FIG. 1, reference numeral 10 denotes a heat exchange can body of a hot water heater. A burner 20 such as a gas burner and an air supply fan 30 are installed on the heat exchange can body 10. Heat exchange heating is performed by the heat exchanger 41 to supply hot water. 50 is a CO sensor provided near the exhaust port of the heat exchange can 10, 60 is a controller of a hot water heater, and 70 is a remote controller. 81 is an incoming water temperature sensor, 82 is an incoming water flow rate sensor, and 83 is a hot water supply temperature sensor.
In FIG. 1, although the exhaust unit and the air supply unit are provided separately, the water heater is configured to supply and exhaust air by a forced air supply / exhaust mechanism in which the air supply unit and the exhaust unit are configured together. May be.
When the hot water supply operation is started, the controller 60 calculates the necessary combustion heat amount as the target combustion heat amount Qm, and further sets a corresponding target fuel supply amount corresponding to the target combustion heat amount Qm. The target air volume Fm is set. During the hot water supply operation, the actual combustion heat quantity Qj is calculated, the CO concentration of the exhaust gas is detected by the CO sensor 50, and the actual air quantity Fj by the air supply fan 30 can be detected. Such information is input to the controller 60.
The target combustion heat quantity Qm is calculated from the set hot water supply temperature, the incoming water temperature, and the incoming water flow rate. The actual combustion heat quantity Qj is calculated from the actual hot water supply temperature, incoming water temperature, and incoming water flow rate. The target air volume Fm is set corresponding to the target combustion heat quantity Qm. The actual air volume Fj can be obtained by detecting the value of the current flowing through the motor of the supply fan 30 and the number of rotations during operation.
[0011]
With reference to FIG. 2, a first embodiment of the method of the present invention will be described. During hot water combustion, the controller 60 calculates the actual combustion heat quantity Qj at regular intervals, and a difference ΔQ (= Qm−Qj) from the target combustion heat quantity Qm previously calculated and stored at the start of hot water combustion is determined in advance. It is monitored whether or not the stored reference heat amount difference ΔQk is greater than or equal to (step S1). If YES in step S1, that is, if the difference ΔQ between the target combustion heat quantity Qm and the actual combustion heat quantity Qj is greater than or equal to the reference heat quantity difference ΔQk, whether or not the CO concentration by the CO sensor 50 is greater than or equal to the reference CO concentration Gk. Is determined (step S2). If the answer is YES in step S2, that is, if the CO concentration is equal to or higher than the reference CO concentration Gk, the controller 60 increases the rotational speed of the air supply fan 30 (step S3). This increase in fan rotation speed is repeated until the CO concentration reaches an appropriate value (step S4). The increase in the number of fan rotations can be increased by a predetermined number of rotations.
On the other hand, if the answer is NO in step S2, that is, if the CO concentration is less than the reference CO concentration, the controller 60 increases the amount of fuel supplied to the burner 20 (step S5). This increase in the fuel supply amount is repeated until the actual combustion heat quantity Qj substantially matches the target combustion heat quantity Qm (step S6). For example, in the case of gas fuel, the fuel supply amount can be increased by increasing the gas pressure by adjusting the gas pressure.
[0012]
With reference to FIG. 3, a second embodiment of the method of the present invention will be described. The controller 60 obtains the actual air volume Fj from the current value and the rotational speed of the motor of the air supply fan 30 at regular intervals during hot water combustion, and the difference ΔF (= Fm−Fj) from the target air volume Fm is determined and stored. It is monitored whether or not the reference air volume difference ΔFk is greater than or not (step S11). If YES in step S11, that is, if the difference ΔF between the target air volume Fm and the actual air volume Fj is greater than or equal to the reference air volume difference ΔFk, it is further determined whether or not the CO concentration by the CO sensor 50 is greater than or equal to the reference CO concentration Gk. Determination is made (step S12). If the answer is YES in step S12, that is, if the CO concentration is equal to or higher than the reference CO concentration Gk, the controller 60 increases the rotational speed of the air supply fan 30 (step S13). The increase in the fan rotation number can increase a predetermined constant rotation number, and after the increase, the process returns to step S1.
On the other hand, if the answer is NO in step S12, that is, if the CO concentration is less than the reference CO concentration, the controller 60 determines that the burner 20 has failed to transfer (step S14), and once reduces the fan speed (step S14). S15). This reduction in the number of revolutions reduces the number of revolutions to a level at which the flame easily moves. Then, the fan rotational speed is restored again after a certain time (step S16). The certain time is set in advance as a time required for the fire transfer. After returning the fan rotation speed to the original value, the controller 60 determines again whether the CO concentration is equal to or higher than the reference CO concentration Gk (step S17). If it is higher (Yes in step S17), step S13 is performed. Migrate to If the answer is NO in step S17, it is determined that the burn-in failure remains, so the controller 60 causes the remote controller 70 to display an error (step S18).
[0013]
Next, a third embodiment of the method of the present invention will be described with reference to FIG. The controller 60 monitors whether the CO concentration by the CO sensor 50 is equal to or higher than the reference CO concentration Gk at regular intervals during hot water combustion (step S21). In the case of YES in step S21, the actual air volume Fj is further obtained, and it is determined whether or not the difference ΔF (= Fm−Fj) from the target air volume Fm is equal to or greater than the reference air volume difference ΔFk that is determined and stored in advance. Determination is made (step S22).
If yes in step S22, that is, if the difference ΔF between the target air flow rate Fm and the actual air flow rate Fj is equal to or greater than the reference air flow difference ΔFk, the controller 60 determines that the combustion is incomplete due to the supply / exhaust blockage (step S23). Then, the rotational speed of the air supply fan 30 is increased (step S24), and the combustion is continued (step S25).
On the other hand, in the case of No in step S22, that is, when the difference ΔF between the target air volume Fm and the actual air volume Fj is less than the reference air volume difference ΔFk, the controller 60 sets the ambient atmosphere in which the water heater is disposed to a low oxygen state. It is determined that there is (step S26), and a warning is given on the remote controller 70 (step S27). This warning is preferably a sound warning by a buzzer or the like, but may be displayed. Of course, it may be controlled to stop the combustion after giving the warning.
In the first and second embodiment examples, the reference CO concentration Gk used does not necessarily have the same value.
[0014]
【The invention's effect】
The present invention has the above-described configuration and operation, and according to the combustion control method for a hot water heater according to claim 1, a burner that burns fuel gas and the like, an air supply fan that supplies air to the combustion of the burner, and a hot water supply A heat exchanger for heating water with the heat generated by the combustion to make warm water, a CO sensor for detecting the CO concentration of exhaust gas, a controller for controlling the whole mechanism, and a combustion control method for a water heater having at least a remote controller When the difference obtained by subtracting the actual combustion heat amount from the set target combustion heat amount becomes equal to or greater than a certain reference heat amount difference during combustion of the burner, the CO concentration of the exhaust gas at that time is further constant. It is determined whether the CO concentration is equal to or higher than the reference CO concentration. If the CO concentration is equal to or higher than a certain reference CO concentration, the rotation speed of the supply fan is increased so that the CO concentration is less than the certain reference CO concentration. And controls so as to increase the amount of fuel supplied to the burner in the case,
When the actual combustion heat quantity is insufficient with respect to the target combustion heat quantity, the CO concentration in the exhaust gas is judged to determine whether the cause is incomplete combustion or the fuel supply quantity is insufficient As a result, when the output of the actual combustion amount is not sufficiently increased, it is possible to ensure appropriate combustion by performing appropriate measures and adjustments according to the cause.
Further, according to the combustion control method for a hot water heater according to claim 2, a burner that burns fuel gas and the like, an air supply fan that supplies air to the combustion of the burner, and heat generated by the combustion of water for hot water supply A hot water heater combustion control method comprising at least a heat exchanger that heats the water in a hot water, a CO sensor that detects the CO concentration of exhaust gas, a controller that controls the entire mechanism, and a remote controller, during combustion of the burner When the difference obtained by subtracting the actual air volume from the target air volume set corresponding to the target combustion heat quantity is equal to or larger than a certain reference air volume difference, the CO concentration of the exhaust gas at that time is more than a certain standard CO concentration. If the CO concentration is equal to or higher than a certain reference CO concentration, the rotational speed of the air supply fan is increased. If the CO concentration is less than the certain reference CO concentration, Salary And controls to reduce the rotational speed of the fan,
By judging the difference between the target air volume and the actual air volume and the CO concentration in relation to the reference values, it is possible to determine whether the cause of the combustion failure is due to incomplete combustion or the burner failure due to burn-in. This also makes it possible to ensure proper combustion by taking appropriate measures and adjustments according to the causes .
[Brief description of the drawings]
FIG. 1 is a schematic view of a water heater that implements the method of the present invention.
FIG. 2 is a control flowchart showing a first embodiment of the method of the present invention.
FIG. 3 is a control flowchart showing a second embodiment of the method of the present invention.
FIG. 4 is a control flowchart showing a third embodiment of the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Heat exchange can body 20 Burner 30 Supply air fan 40 Inlet pipe 41 Heat exchanger 50 CO sensor 60 Controller 70 Remote control 81 Incoming water temperature sensor 82 Incoming water flow sensor 83 Hot water supply temperature sensor

Claims (2)

  Burner that burns fuel gas, etc., an air supply fan that supplies air to the combustion of the burner, a heat exchanger that heats water for hot water supply with the heat generated by the combustion to make warm water, and the CO concentration of exhaust gas A water heater combustion control method comprising at least a CO sensor to detect, a controller for controlling the entire mechanism, and a remote controller, wherein a difference obtained by subtracting an actual combustion heat amount from a set target combustion heat amount is constant during combustion of the burner When the difference in the reference calorific value is greater than or equal to, it is further determined whether or not the CO concentration of the exhaust gas at that time is equal to or higher than a certain reference CO concentration, and the CO concentration becomes equal to or greater than the certain reference CO concentration. If the number of revolutions of the water heater is increased, the number of revolutions of the air supply fan is increased, and when the CO concentration is less than a certain reference CO concentration, the fuel supply amount to the burner is increased. Burn control method.   Burner that burns fuel gas, etc., an air supply fan that supplies air to the combustion of the burner, a heat exchanger that heats water for hot water supply with the heat generated by the combustion to make warm water, and the CO concentration of exhaust gas A combustion control method for a water heater comprising at least a CO sensor for detecting, a controller for controlling the entire mechanism, and a remote controller, wherein an actual air volume is calculated from a target air volume set corresponding to a target combustion heat quantity during combustion of the burner. When the subtracted difference is equal to or greater than a certain reference air volume difference, it is further determined whether or not the CO concentration of the exhaust gas at that time is equal to or greater than a certain reference CO concentration. When the concentration is higher than the concentration, the rotation speed of the supply air fan is increased, and when the CO concentration is lower than a certain reference CO concentration, the rotation speed of the supply air fan is once decreased. Combustion control method for water heater to be.

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