JP4873237B2 - Gas water heater - Google Patents

Description

  The present invention is a gas that can exhibit the combustion amount at the original maximum output number of the apparatus even if the exhaust resistance increases due to clogging of the supply / exhaust passage or blowing from the outlet of the exhaust passage under strong wind. It relates to a water heater.

  Conventionally, as this kind of gas hot water supply device, by changing and controlling the energization current value to the gas proportional valve according to the change of the fan motor current value of the blower fan, the blowing characteristics due to disturbance (back wind blown into the exhaust passage, etc.) It is known that the gas amount can be changed promptly even if changes occur (see, for example, Patent Document 1).

  Furthermore, when clogging occurs in the air supply section or exhaust section, clogging is detected by utilizing the decrease in the load current value of the fan motor of the blower fan, and the drive current value falls below the threshold value. For example, there is known one that corrects whether to increase the rotational speed of the fan motor or reduce the opening of the gas proportional valve (see, for example, Patent Document 2).

Japanese Patent No. 2870436 JP 2003-14296 A

  By the way, when the gas hot water supply device is installed in a high-rise house or the like, it is easy to be affected by strong winds, and the exhaust resistance is likely to increase due to the blowing of strong winds from the outlet of the exhaust passage. On the other hand, normally, when an increase in the exhaust resistance is detected, control for increasing the number of rotations of the fan motor of the blower fan by a predetermined amount and maintaining the blown air amount (air supply amount of combustion air) constant is performed. It will be repeated. For example, FIG. 8 shows a normal time indicated by a solid line so as to show the relationship between the output number (control number) and the fan speed in a gas water heater capable of switching the combustion capacity in three stages from capacity 1 to capacity 3. The characteristic line is changed to the characteristic line indicated by the one-dot chain line by one increase of the predetermined rotational speed as described above, and further, the second predetermined rotation speed is increased to change to the characteristic line indicated by the two-dot chain line. In this way, the control is performed to keep the air flow rate constant against the exhaust resistance by repeatedly correcting the rotational speed of the fan.

  However, in the combustion chamber, exhaust resistance increases due to the backflow inflow from the exhaust passage side, and air is pushed in from the air supply passage side by the increased number of rotations. The internal pressure tends to increase. For this reason, even if the same amount of gas is supplied and controlled through the gas proportional valve, the actual amount of gas supplied to the combustion chamber tends to decrease more than that in the original control due to the above-mentioned tendency to increase the internal pressure. Become.

  For example, as shown in FIG. 9, the characteristic line indicated by the solid line in the normal state is the one-time fan rotation of FIG. 8, as shown in the relationship between the output number and the gas amount (gas supply amount) per burner. Even if the opening of the gas proportional valve is kept the same, it decreases to the characteristic line of the one-dot chain line after the increase of the number, and decreases to the characteristic line of the two-dot chain line after the increase of the fan speed twice. The actual gas supply to the burner will be reduced. As a result, the amount of combustion is reduced, and the gas water heater with the maximum output number of 24 can output up to 2400 kcal / h, for example, although it can output up to 2600 kcal / h per burner. Invite a situation where the original hot water supply performance cannot be demonstrated, or the hot water supply flow rate is reduced based on FB (feedback) control to maintain the hot water supply at the set hot water temperature. Will cause inconvenience. In addition, as shown in FIG. 9, the combustion amount (gas amount) at the capacity switching point when reducing the combustion amount is reduced to a region where the combustion amount (gas amount) is easily blown off (see the region indicated by the broken line in FIG. 9) Ds. It will also end up.

  On the other hand, in order to cope with these, the degree of increase in the exhaust resistance is detected, and the degree of increase in the internal pressure of the combustion chamber is accurately grasped based on the degree of increase, and the blast volume and gas supply amount are adjusted accordingly. Although control (correction control) is also conceivable, the control becomes complicated and new sensors (for example, equipment for detecting pressure in the combustion chamber) need to be added.

  The present invention has been made in view of such circumstances, and the object of the present invention is to achieve a certain degree of accurate combustion characteristics while adopting relatively simple control, and under exhaust resistance. The object is to provide a gas hot water supply device that can exhibit the original maximum output number. Another object is to realize a reliable combustion operation.

  In order to achieve the above object, the present invention provides a combustion burner that burns fuel gas and discharges exhaust gas from an exhaust passage, and a gas that changes and adjusts the combustion amount by changing and controlling the amount of gas supplied to the combustion burner. A combustion engine comprising: a proportional valve; a blower fan that supplies combustion air to the combustion burner by rotating a fan motor; and a heat exchanger that heats and heats incoming water by combustion heat of the combustion burner. The following specific items are provided for a gas hot water supply apparatus that discharges hot water at a set hot water temperature by adjusting the amount of change and adjusting the flow rate from incoming water to hot water. That is, when an increase in the exhaust resistance of the exhaust passage is detected, the fan rotation speed of the blower fan is increased to maintain the air supply amount to the combustion burner, while the gas supply amount change adjustment adjustment by the gas proportional valve is performed. Control at the time of exhaust resistance generation that changes the upper limit value for adjustment of the gas supply amount to the increasing side while maintaining the upper limit value for flow rate adjustment that is set in advance as corresponding to the upper limit value Means are provided (claim 1).

  In the case of this invention, since the upper limit value (for example, the set maximum output number) on the change adjustment of the gas supply amount is changed to the increasing side, the gas supply amount of the set maximum output number is supplied from the gas proportional valve. However, the actual gas supply amount tends to decrease due to the increase in the internal pressure of the combustion chamber due to the increase in exhaust resistance and fan rotation speed. Based on the output number increased above the set maximum output number The gas supply amount by the gas proportional valve can be corrected to increase, and the gas supply amount based on the original set maximum output number can be supplied to the combustion chamber whose internal pressure has increased. On the other hand, according to the degree of exhaust resistance, that is, the degree of increase in the gas supply amount, etc., originally according to the degree of increase in the internal pressure of the combustion chamber, it is necessary to accurately determine the upper limit of the gas supply amount change adjustment. Even in the process of only changing the value to the increase side, for example, the upper limit value (for example, the set maximum flow rate value) for flow rate adjustment corresponding to the above set maximum output number is the normal value without exhaust resistance. For example, even if an excessive gas supply amount is requested by the FB control, it is possible to prevent the combustion amount from reaching excessively due to the restriction of the set maximum flow rate value. . As described above, it is possible to achieve combustion characteristics that are accurate to some extent while adopting relatively simple control, and the original set maximum output number can be exhibited even under exhaust resistance.

  The combustion burner according to the present invention includes two or more combustion burner portions that can supply and shut off fuel gas independently, and the combustion ability is changed by switching the combustion burner portion to be burned by selective supply switching of the fuel gas. When the increase in the exhaust resistance of the exhaust passage is detected as the exhaust resistance generation control means, the combustion burner is controlled in response to the increase in the fan rotational speed. The gas amount set value that defines the small gas amount side boundary in the switching control of the combustion capacity can be changed to the increasing side (claim 2). Due to the increase in the internal pressure of the combustion chamber described above, the actual gas supply amount tends to decrease, and the gas amount at the small gas amount side boundary on the switching control of the combustion capacity decreases to a region where it is easy to blow out. It may cause a fear of. On the other hand, by changing the gas amount setting value that defines the small gas amount side boundary in the switching control as described above to the increasing side, the risk of misfire can be surely avoided and even under exhaust resistance. A reliable combustion operation can be realized.

  As described above, according to the gas hot water supply device of claim 1 or claim 2, even if the combustion chamber has an internal pressure increased due to exhaust resistance and fan speed increase control, The gas supply amount based on the output number can be supplied, and combustion based on the original set maximum output number can be realized. And while realizing such an effect by simply changing the upper limit limit value on the adjustment adjustment of the gas supply amount to the increase side, the upper limit limit value on the flow rate adjustment is the same as the normal condition without exhaust resistance. By maintaining it as it is, it is possible to suppress the combustion amount from becoming excessive and to realize the combustion state based on the set maximum output number almost accurately. As described above, it is possible to achieve combustion characteristics that are accurate to some extent while adopting relatively simple control, and to exhibit the original set maximum output number even under exhaust resistance.

  In particular, according to claim 2, even if a combustion burner that switches the combustion capacity stepwise is employed, the possibility of misfire can be reliably avoided, and a reliable combustion operation can be realized even under exhaust resistance. It becomes like this.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a gas hot water supply apparatus according to an embodiment of the present invention. In the figure, reference numeral 2 denotes a can housed in a housing 1, in which a heat exchanger 3 and two or more (two groups in the illustrated example) combustion burner portions for burning gas as fuel. 4a and 4b are disposed, and a blower fan 5 for supplying combustion air by a rotation operation of the fan motor 51 is provided on the lower side. A combustion burner is constituted by the two or more combustion burner portions 4a and 4b.

  The heat exchanger 3 includes a water inlet pipe 6 for allowing water supplied from a water pipe or an elevated water tank to enter the heat exchanger 3, and a hot water outlet pipe 7 for discharging hot water heated in the heat exchanger 3. They are connected in communication with each other. The hot water discharge pipe 7 is connected to a hot water supply pipe (not shown), and hot water is supplied to a hot water tap such as a kitchen or a washroom through the hot water supply pipe. The water intake pipe 6 is provided with an incoming water flow rate sensor 8 for detecting the incoming water flow rate, and an incoming water temperature sensor 9 for detecting the incoming water temperature, and the hot water outlet pipe 7 has a hot water temperature immediately after coming out of the heat exchanger 3. A can body temperature sensor 10 for detecting the temperature of the can body 2 by detecting the temperature, a flow rate adjusting valve 11 for controlling the hot water supply flow rate, and a hot water temperature sensor 12 for detecting the temperature of the hot water supplied to the hot water tap. It is intervened. Each of the temperature sensors 9, 10, 12 is constituted by a thermistor, for example.

  A bypass pipe 13 is connected between the water inlet pipe 6 and the hot water outlet pipe 7, and a bypass water amount adjustment valve 14 for adjusting the bypass flow rate of tap water from the water inlet pipe 6 is interposed in the middle of the bypass pipe 13. It is disguised. The bypass water amount adjusting valve 14 is controlled by a controller 21 described later, and temperature adjustment (temperature adjustment) of the hot water temperature is performed by mixed water.

  Each of the plurality of combustion burner parts 4a and 4b includes a plurality of burners (four first combustion burner parts 4a, for example, six second combustion burner parts 4b, for example). Connected to 4a and 4b is a gas supply pipe 15 for supplying gas as a combustion fuel from the fuel gas supply source side. The gas supply pipe 15 is provided with an original gas solenoid valve 16 as an original plug and a gas proportional valve 17 for adjusting the gas supply flow rate in order from the fuel gas supply source side. The gas supply pipe 15 is branched downstream of the gas proportional valve 17, gas is supplied to the first combustion burner portion 4a via the first capacity switching valve GV1, and the second combustion burner portion 4b. On the other hand, gas is supplied through the second capacity switching valve GV2. With the selective opening / closing switching control of the first and second capacity switching valves GV1, GV2 and the change adjustment control of the gas supply amount of the gas proportional valve 16, the combustion capacity can be changed and adjusted stepwise and continuously. Is variable. For example, only the first capacity switching valve GV1 is opened and only the first combustion burner section 4a is burned (capability 1), the first capacity switching valve GV1 is closed and only the second capacity switching valve GV2 is opened and the second combustion burner is opened. Only the portion 4b is burned (capability 2), or both the first and second capability switching valves GV1, GV2 are opened to burn both the first and second combustion burner portions 4a, 4b (capability 3). As described above, the ability switching of the combustion amount from ability 1 to ability 3 is possible.

  If the maximum output number is, for example, the specification of No. 24 as the output (heat quantity) after heat exchange in the heat exchanger 3, that is, the output capacity in the range of a predetermined minimum output number to No. 24. Is variable. In addition, 1.0 is a hot-water discharge capacity capable of raising the temperature of 1 L / min of water by 25 ° C., and corresponds to a value obtained by multiplying a heat generation amount corresponding to a gas consumption amount due to combustion by a heat exchange efficiency.

  The combustion burner parts 4a and 4b receive the supply of combustion air from the blower fan 5 and are combusted. The combustion heat heats and heats the incoming water flowing through the heat exchanger 3 while the exhaust gas flows into the exhaust passage. It is discharged outside through 2a.

  The hot water supply operation by the combustion operation of the combustion system constituted by the combustion burner parts 4a, 4b and the like is controlled by a controller 21 (see FIG. 2) provided with an MPU, a memory and the like. Various controls such as correction control when exhaust resistance occurs are performed based on hot water supply operation control in which hot water is supplied based on the set hot water temperature. That is, as shown in FIG. 2, the controller 21 is connected to the remote controller 22 and includes a hot water supply control means 23 and an exhaust resistance generation control means 24. The remote controller 22 and various sensors 8, 9, 10, The combustion system, the flow control valve 11 and the like are controlled to operate based on the output signal from 12, the change of the energization current value to the fan motor 51, and the like.

  The hot water supply control means 23 is premised on FF (feed forward) control and FB (feedback) control, and performs various processes such as an air amount control unit 25, a gas amount control unit 26, a flow rate control unit 27, and a capacity switching control unit 28. Is executed based on the control number (output number) such as the FF control number FB control number. The basic hot water supply control by the hot water supply control means 23 will be described. When the user opens the hot water tap with the desired hot water temperature (set hot water temperature) being input to the remote controller 22, water is introduced from the water intake pipe 6, and the water enters. The hot water supply operation control is started by receiving a flow rate detection from the flow rate sensor 8 exceeding the minimum operating water amount (MOQ), and the user shuts the hot water tap and the detected value from the incoming water flow rate sensor 8 is the minimum operating flow rate. If it becomes lower than that, combustion by the combustion system is stopped and hot water supply operation control is ended.

  The hot water supply operation control is performed by operating the combustion system so that hot water having the set hot water temperature is discharged. In this combustion operation control, first, the combustion operation is performed based on the detected value from the incoming water flow rate sensor 8 or the incoming water temperature sensor 9 based on the FF control number corresponding to the set hot water temperature, and then the can body temperature sensor 10 or the hot water temperature. The combustion operation is performed in consideration of the FB control number based on the detected temperature from the sensor 12. The combustion operation based on the target control number of the above-mentioned FF control number or FB control number is a combustion burner unit that performs combustion operation by selectively opening the first and second capacity switching GV1, GV2 by the capacity switching control unit 28. After setting the number of 4a, 4b to a predetermined number, from the gas amount control unit 26 and the air amount control unit 25 so as to obtain a gas supply amount and an air supply amount corresponding to the target control number at a predetermined air-fuel ratio. This is realized by outputting an operation signal. That is, an operation signal is output from the gas amount control unit 26 to the gas proportional valve 17 so that a predetermined gas supply amount is obtained, and the gas proportional valve 17 is operated at a predetermined rotation speed so as to achieve an air supply amount that realizes a predetermined air-fuel ratio. An operation signal is output from the air amount control unit 25 to the fan motor 51 of the blower fan 5, so that a combustion state of a target control number, that is, a predetermined output number is set.

  The above FF control number is the amount of combustion required to raise the incoming water to the set hot water temperature based on the incoming water flow rate from the incoming water flow rate sensor 8, the incoming water temperature from the incoming water temperature sensor 9, and the set hot water temperature. It is obtained by calculation as (amount of heat). Then, the FB control number is set based on, for example, the temperature difference between the actual hot water temperature detected by the hot water temperature sensor 12 and the set hot water temperature so that the actual hot water becomes the set hot water temperature. Increase / decrease of number of issues for

  The control by the gas amount control unit 26 at the normal time when no exhaust resistance is generated is performed as shown in FIG. That is, after combustion is started by the above FF control number, the FB control number is calculated, the FB control number is added to the FF control number, and the output number (output number = FF Calculation processing of control number + FB control number) is performed (step S110). It is determined whether or not the calculated output number (displayed as “FF + FB” in FIG. 3) is larger than the maximum output number (MAX number: for example, 24) as the upper limit value of the gas supply amount (step 24). S120), if larger, the MAX number is set as the output number (step S130), and if smaller than the maximum output number, the calculated output number is used as it is (step S140) to perform the gas output process. (Step S150). The gas output processing is performed by the operation signal for the gas proportional valve 17 and the output of the operation signal for the blower fan 5, and this is repeated. In short, the output number is limited so as not to exceed the MAX number.

  In addition, the flow rate control unit 27 determines a set maximum flow rate value (for example, 24 L / min) so as not to exceed the MAX number, and the flow rate change adjustment by the flow rate control valve 11 is an upper limit value for flow rate adjustment. The flow rate is controlled so as not to exceed a certain set maximum flow rate value. That is, as shown in FIG. 3 (b), the maximum flow rate for control in the current combustion state is obtained by dividing the MAX number by the temperature difference between the set hot water temperature and the detected incoming water temperature (step S21), If this maximum flow rate is higher than the above 24 L / min, the flow rate is limited to 24 L / min (YES in step S22, step S23), and if smaller, the value calculated in step S21 is used as it is (NO in step S22). The flow rate is controlled by the control valve 11.

  When the exhaust resistance is generated during the combustion operation, the exhaust resistance generation control means 24 increases the rotation speed of the blower fan 5 by the set rotation speed and the control number (output number). The maximum gas amount change control part that changes and expands the limit (the upper limit is the MAX number), and the minimum gas amount and the set output number of the capacity switching point in the capacity switching control unit 28 are increased. Each control with the ability switching point change control portion to be performed is executed.

  As shown in FIG. 4, the basic control portion monitors the change in the load current value for the fan motor 51 (step S1). When the load current value decreases (YES in step S1), the amount of decrease is preliminarily determined. If it is greater than the set threshold value, it is determined that exhaust resistance has occurred (YES in step S2). If it is less than the determined value, it is determined that no exhaust resistance that requires countermeasures has occurred. The monitoring of the change in the load current value in step S1 is continued (NO in step S2). If it is determined that the exhaust resistance has occurred, the rotational speed of the blower fan 5 is increased by the set rotational speed (step S3), and the number of times N that is the number of times the rotational speed is increased is “1”. Is added (step S4). Steps S1 to S4 are repeated until the up rotation speed N reaches a predetermined number (for example, 10 times), and each time the rotation speed of the blower fan 5 is increased by the set rotation speed (NO in step S5, steps S1 to S4). ). If the fan motor current value continues to decrease even when the number of times of increase N exceeds the predetermined number of times, abnormal processing such as forced stop of combustion is executed (step S6). If only the control by the basic control portion is performed, the characteristic line is changed as shown in FIG.

The maximum gas amount change control portion is changed from the normal control by the gas amount control unit 26 shown in FIG. 3A to the control by the gas amount control unit 26 when the exhaust resistance is generated as shown in FIG. 5A. On the other hand, the flow rate control by the flow rate control unit 27 shown in FIG. 3 (b) maintains the same control contents as it is without changing from the one shown in FIG. 3 (b) as shown in FIG. 5 (b). Yes. In short, in FIG. 5A, although the upper limit based on the MAX number is enlarged and changed to the increase side, the limit of the set maximum flow rate value of 24 L / min is maintained as it is at the normal time. That is, as shown in FIG. 5 (a), after the combustion is started by the FF control number, the FB control number is calculated and the FB control number is calculated by the FF control in the same manner as in step S110. In addition to the number, the output number (output number = FF control number + FB control number) is calculated (step S11). The calculated output number ("FF + FB calculation") is added to the MAX number plus an additional number corresponding to the increase in fan speed (number of times the fan speed is increased N x a predetermined set increase number _A0 ). It is determined whether the number is larger than the enlarged change number (step S12). If the number is larger, the enlarged change number is set as the output number (step S13). Using the output number as it is (step S14), the same gas output processing as in step S150 is performed (step S15). In short, the upper limit value of the output number is changed from the MAX number to the above-mentioned expanded change number.

  On the other hand, as shown in FIG. 5B, the flow rate control unit 27 performs the same control as the normal control shown in steps S21 to S24 in FIG. 3B, that is, a set maximum flow rate value (for example, 24 L / min). ), And the flow rate is controlled so that the flow rate change adjustment by the flow rate control valve 11 does not exceed the set maximum flow rate value.

The capacity switching point change control part is the minimum gas amount value (gas amount setting value) of the capacity switching point (small gas amount side boundary) when reducing the combustion capacity, among the capacity switching points of capacity 1 to capacity 3. ) To the increasing side, and a changing process to change the setting switching output number of the capacity switching point for executing the capacity switching when the combustion capacity is reduced to the increasing side. These increase side changes are made by adding increments corresponding to the increase in the fan rotation speed in the same manner as described above. That is, with respect to the minimum gas amount value, an increment of the above-mentioned number of times up N × the set increase gas amount G ₀ is added to the normal set minimum gas amount value. An increment of the number of up times N × the set number of increased numbers B ₀ is added to the number of issues.

  As a result of the control by the exhaust resistance generation control means 24 described above, the fan rotational speed is changed from the characteristic line Fn indicated by the solid line at the normal time to the characteristic line F1 indicated by the one-dot chain line by increasing the first set rotational speed as shown in FIG. When the set rotational speed is increased for the second time, the characteristic line F1 is sequentially moved to the two-dot chain line characteristic line F2 to increase the rotational speed. Although not shown, the characteristic line is sequentially moved to the rotational speed increasing side by the third set rotational speed increase. At this time, the capability switching point when the characteristic lines F1, F2,... After the change are reduced is proportional control based on the change on the increasing side of the minimum gas amount value by the capability switching point change control portion and the setting switching output number. It moves by changing the number on the increasing side (see the comparison with the case of only the basic control part in FIG. 8). In addition, as shown in FIG. 7, the amount of gas per burner in the combustion burner portions 4a and 4b in each combustion capacity switching stage (capacity 1 to capacity 3) is the above-mentioned first rotation from the characteristic line Sn. When the number is increased, the characteristic line S1 (see the one-dot chain line in the figure) is moved to the characteristic line S2 (see the two-dot chain line in the figure) by the second rotation speed increase. It is omitted as well). These characteristic lines S1, S2,... Are also moved by the above-mentioned change in the minimum gas amount and the change in the set switching output number (see the comparison with the case of only the basic control portion in FIG. 9). As a result, the gas amount value at the capacity switching point at the capacity switching to the combustion capacity lowering side becomes larger than the region Ds that is easily blown out, and the capacity switching in the reliable stable combustion state by preventing misfire. Is possible.

  Also, in the combustion operation based on the FF control number + FB control number by the control by the maximum gas amount change control part, the calculated value of the output number (= FF control number + FB control number) after the calculation is the MAX number. Even if the number exceeds the maximum, the upper limit is not limited by the MAX number as in the prior art, and an expansion change number is allowed. For this reason, even if the gas flow rate in the gas proportional valve 17 is controlled by an amount corresponding to the MAX number, the actual gas supply amount becomes smaller than the originally controlled gas supply amount due to the increase in internal pressure in the combustion chamber. Therefore, the actual gas supply amount into the combustion chamber can be made the gas supply amount corresponding to the original MAX number against the exhaust resistance, and the original maximum heat amount (gas amount: FIG. 7). 2600 kcal / h). In addition, during such control, the flow rate control valve 11 is controlled under the restriction based on the set maximum flow rate value similar to the normal normal time, so that the above-mentioned FB control number (required number based on the actual tapping temperature). The output number is determined by calculating an increase / decrease number for approaching the number) based on the restriction of the original set maximum flow rate value. As a result, even if the limitation on the MAX number is lifted and the upper limit of the expanded change number is increased, the calculated output number is limited based on the set maximum flow rate value. It can be suppressed that it is higher than the original maximum heat quantity (gas quantity: 2600 kcal / h) based on the number.

  From the above, the upper limit on the output number (MAX number) is removed, and the number is gradually increased to the changed expanded number, while the set maximum flow rate value originally determined for the MAX number is kept as normal. By maintaining this, an accurate and complicated required increase rate for the required increase in the number of revolutions and gas supply corresponding to the exhaust resistance (for example, the correction amount for the decrease in the gas supply due to the increase in the internal pressure of the combustion chamber) It is possible to make the actual gas supply amount to the combustion chamber correspond to the original MAX number, even if exhaust resistance is generated, and there is an excessive amount of combustion without the need for calculation etc. And the maximum combustion amount can be stopped at the original maximum combustion amount. In other words, even if exhaust resistance occurs due to exposure to strong winds (for example, wind speed of 30 m / sec), the reduction of the maximum output number of the gas water heater is prevented and the original maximum output number (for example, 24) is maintained. The amount of combustion can be exhibited. And since such an effect can be solved by control processing, a gas hot water supply device can be configured using a normal inexpensive one that balances with the atmospheric pressure as the gas proportional valve 17. There is no need to use an expensive differential pressure detection type that balances with the internal pressure.

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Various other embodiments are included. That is, in the above embodiment, the exhaust resistance is detected and determined by monitoring the change in the current value of the fan motor. However, the present invention is not limited to this, and other means may be used. For example, the occurrence of exhaust resistance may be detected using a burner sensor.

It is a schematic diagram which shows embodiment of this invention. It is a block diagram which shows the structure of the controller of embodiment. FIG. 3A is a flowchart of the gas amount control, and FIG. 3B is a flowchart of the flow rate control. It is a flowchart which concerns on the up correction | amendment control of the ventilation volume at the time of exhaust resistance generation | occurrence | production. FIG. 5A is a flowchart of the gas amount control, and FIG. 5B is a flowchart of the flow rate control. It is a relationship diagram of the output number and fan rotation speed which concern on a change control part. It is a related figure of the number of outputs concerning the change control part, and the gas amount per burner. FIG. 6 is a relationship diagram between an output signal number and a fan rotation speed related to simple fan rotation speed up correction control. FIG. 9 is a relationship diagram between the output number and the amount of gas per burner in the case of the up correction control of FIG. 8.

Explanation of symbols

2a Exhaust passage 3 Heat exchanger 4a, 4b Combustion burner (combustion burner)
5 Blower fan 17 Gas proportional valve 24 Exhaust resistance generation control means 51 Fan motor

Claims (2)

A combustion burner that burns fuel gas and discharges exhaust gas from the exhaust passage, a gas proportional valve that changes and adjusts the combustion amount by changing and controlling the gas supply amount to the combustion burner, and a fan motor for the combustion burner A blower fan that supplies combustion air by rotation and a heat exchanger that heats and heats the incoming water by the combustion heat of the combustion burner, and adjusts the amount of combustion, and the flow rate from the incoming water to the hot water In the gas hot water supply device that allows the hot water at the set hot water temperature to be discharged by adjustment,
When an increase in the exhaust resistance of the exhaust passage is detected, the upper limit of the gas supply amount change adjustment by the gas proportional valve while increasing the fan rotation speed of the blower fan to maintain the air supply amount to the combustion burner Exhaust resistance generation time control means for changing the upper limit value for adjusting the gas supply amount to the increasing side while maintaining the upper limit value for adjusting the flow rate that is determined in advance as corresponding to the value. Have
A gas water heater characterized by that. The gas hot water supply device according to claim 1,
The combustion burner is provided with two or more combustion burner portions that can supply and shut off fuel gas independently, and the combustion capability is gradually changed by switching the combustion burner portion to be burned by selective switching of the fuel gas. Configured to be switched and
When the exhaust resistance generation control means detects an increase in the exhaust resistance of the exhaust passage, the control means defines a small gas amount side boundary in the switching control of the combustion capacity of the combustion burner in response to the increase in the fan speed. It is configured to change the gas amount set value to be increased further,
A gas water heater characterized by that.

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