JP2013242096A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion device capable of stably performing combustion operation by efficiently preventing dew condensation on a nozzle surface of a nozzle manifold, in the combustion device performing post purge operation after the stop of the combustion.SOLUTION: A combustion device comprises: a gas burner 1 burning fuel gas supplied from a nozzle manifold 8; a combustion fan 50; and an outside air temperature detection part 90 detecting an outside air temperature. When performing post purge operation for rotating the combustion fan 50 after the stop of the combustion, a post purge discharge wind volume is set in accordance with the outside air temperature.

Description

  The present invention relates to a combustion apparatus that performs a post-purge operation for rotating a combustion fan for a predetermined time after combustion is stopped.

  In a combustion apparatus having a gas burner that burns fuel gas and a combustion fan that supplies combustion air to the gas burner, combustion exhaust gas generated by the combustion operation is discharged and the apparatus is cooled. A post purge operation is performed in which the fan is continuously rotated for a predetermined time. In general, the operation time of the combustion fan in the post-purge operation is set to a fixed time from the stop of combustion in consideration of the internal volume of the device and the capacity of the combustion fan, but an abnormality has occurred in the motor of the combustion fan, etc. In some cases, the post-purge operation may end with insufficient cooling in the apparatus. For this reason, for example, a temperature sensor that detects the temperature of hot water heated by combustion of the gas burner is provided, and the hot water heating device that changes the post-purge operation time of the combustion fan based on the hot water temperature detected by the temperature sensor Has been proposed (for example, Patent Document 1).

JP-A-11-101449

  By the way, in a combustion apparatus employed in a water heater or the like, a combustion section is formed by arranging a plurality of flat gas burners adjacent to each other in one direction. Each gas burner having the above structure is supplied with fuel gas from a plurality of nozzles provided in the nozzle manifold.

  On the other hand, in a combustion apparatus in which an exhaust port for discharging combustion exhaust gas is open to the outdoors, a gas burner and a nozzle manifold in the apparatus communicate with the outdoors via the exhaust port. For this reason, when strong winds are blowing outdoors, exhaust of the combustion exhaust gas is hindered from the exhaust port, and the warm and moist combustion exhaust gas may flow backward into the apparatus by the wind entering from the exhaust port.

  When the backflow of combustion exhaust gas as described above occurs when the outside air temperature is low, each nozzle of the nozzle manifold corresponds to the gas inlet provided in each gas burner, so that moisture in the combustion exhaust gas is nozzle Condensation on the surface tends to cause nozzle clogging. Therefore, not only when the motor or the like is abnormal, but also when the reverse flow as described above occurs, if the post purge operation is insufficient, there is a problem that combustion failure occurs during the next combustion operation. In particular, when the combustion operation is performed for a short time, since the combustion is stopped in a state where the gas burner is not sufficiently heated, the temperature of the nozzle surface of the nozzle manifold is not increased, and condensation is likely to occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to efficiently prevent condensation on the nozzle surface of a nozzle manifold in a combustion apparatus in which a post-purge operation is performed after combustion is stopped. An object of the present invention is to provide a combustion apparatus capable of performing a stable combustion operation.

The present invention comprises a gas burner for burning fuel gas supplied from a nozzle manifold,
A combustion fan for supplying combustion air to the gas burner;
An outside air temperature detector for detecting outside air temperature,
An exhaust passage for discharging exhaust gas generated by combustion of the gas burner from an exhaust port communicating with the outdoors;
A control unit that controls a post-purge operation of a combustion fan for discharging the combustion exhaust gas after the combustion of the gas burner is stopped,
The said control part is a combustion apparatus which sets the post-purge discharge | emission air volume of the said combustion fan based on the external temperature detected by the said external temperature detection part.

  Condensation on the nozzle surface of the nozzle manifold is likely to occur when the combustion exhaust gas flows backward while the outside air temperature is low and the temperature in the apparatus is low. Therefore, dew condensation can be prevented by setting the post-purge discharge air volume of the combustion exhaust gas discharged by the post-purge operation of the combustion fan according to the outside air temperature.

Preferably, in the combustion apparatus,
The controller further sets the post-purge exhaust air volume based on the combustion time of the gas burner.

  If the gas burner burns for a certain time or more, the nozzle surface of the nozzle manifold that supplies the fuel gas to the gas burner also rises in temperature due to heat transfer, so that condensation is unlikely to occur even when the outside air temperature is low. Therefore, if the post-purge discharge air volume is set based on both the outside air temperature and the combustion time of the gas burner, the post-purge operation can be performed efficiently.

In the combustion apparatus,
The setting of the post-purge exhaust air volume is set by the post-purge operation time of the combustion fan and / or the post-purge operation flow rate of the combustion fan.

  Since the amount of combustion exhaust gas discharged by the post-purge operation is determined by the operation time and operation flow rate of the combustion fan, the post-purge exhaust air volume can be set by using either or both of these as setting elements. .

Preferably, in setting the post-purge discharge air volume, the control unit sets an initial post-purge operation time for the combustion fan when the outside air temperature detected by the outside air temperature detecting unit is equal to or higher than a first determination temperature. Set the operation time
Even if the outside air temperature detected by the outside air temperature detecting unit is lower than the first determination temperature, if the combustion time of the gas burner is equal to or longer than the first determination time, the post purge operation time of the combustion fan is set to the initial post purge. Set the operation time
If the outside air temperature detected by the outside air temperature detection unit is less than the first determination temperature and the combustion time of the gas burner is less than the first determination time, the post-purge operation time of the combustion fan is set from the initial post-purge operation time. Set too long.

  According to the above combustion apparatus, when the outside air temperature at which condensation is unlikely to occur on the nozzle surface is equal to or higher than the first determination temperature, the post purge operation time of the combustion fan is set to the initial post purge operation time. Even if the temperature is below the judgment temperature, if the combustion time of the gas burner is long, the nozzle surface of the nozzle manifold is warmed and condensation is unlikely to occur, so the post purge operation time of the combustion fan is set to the initial post purge operation time. By setting, condensation can be prevented efficiently. On the other hand, when the outside air temperature is lower than the first judgment temperature and the combustion time of the gas burner is short, the temperature of the nozzle manifold does not rise and the condensation is more likely to occur. Is set longer than the initial post-purge operation time, the combustion exhaust gas can be reliably discharged out of the apparatus.

Preferably, the control unit goes back a certain time from the combustion stop even if the outside air temperature detected by the outside air temperature detecting unit is less than the first determination temperature and the combustion time of the gas burner is less than the first determination time. When the total combustion time of the gas burner within the retroactive time is equal to or longer than the second determination time, the post purge operation time of the combustion fan is set to the initial post purge operation time,
The outside combustion temperature detected by the outside air temperature detection unit is less than the first determination temperature, the combustion time of the gas burner is less than the first determination time, and further, the total combustion of the gas burner within a retroactive time that is a certain time retroactive from the combustion stop When the time is less than the second determination time, the post purge operation time of the combustion fan is set longer than the initial post purge operation time.

  Even if the combustion operation is completed in a short time, if the combustion operation has been performed for a certain period of time or more recently, the nozzle surface of the nozzle manifold is warmed, so that condensation is unlikely to occur. Therefore, according to the combustion apparatus, since the post-purge operation time is set in consideration of not only the current combustion operation but also the combustion operation that has been performed so far, dew condensation can be more efficiently prevented.

Preferably, in the combustion apparatus,
In setting the post-purge discharge air volume, the control unit sets the post-purge operation time of the combustion fan longer as the outside air temperature decreases.

  According to the combustion apparatus, as the outside air temperature decreases, the post-purge operation time of the combustion fan is set longer, so that condensation can be reliably prevented.

Preferably, the combustion device further includes:
From the group consisting of an internal temperature detector that detects the temperature in the vicinity of the nozzle, an exhaust gas temperature detector that detects the temperature of the combustion exhaust gas near the exhaust port, and a carbon monoxide concentration detector that detects the carbon monoxide concentration in the apparatus. Having at least one detector selected,
The control unit includes a nozzle vicinity temperature detected by the internal temperature detection unit, a combustion exhaust gas temperature detected by the exhaust temperature detection unit, and a carbon monoxide concentration detected by the carbon monoxide concentration detection unit. The post-purge operation time of the combustion fan is set based on at least one detection result selected from the group.

  According to the combustion apparatus, since the residue of the combustion exhaust gas in the apparatus can be directly detected, condensation can be prevented more reliably.

  As described above, according to the present invention, in the combustion apparatus in which the post-purge operation is performed after the combustion is stopped, dew condensation on the nozzle surface of the nozzle manifold can be efficiently prevented, so that the combustion operation can be performed stably. .

FIG. 1 is a schematic side view showing an example of a gas burner and a nozzle manifold according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of the gas burner according to the embodiment of the present invention. FIG. 3 is a schematic diagram showing an example of the combustion apparatus according to the embodiment of the present invention. FIG. 4 is a control flowchart showing an example of a control operation of the post-purge operation in the combustion apparatus according to the embodiment of the present invention. FIG. 5 is a control flowchart showing another example of the control operation of the post-purge operation in the combustion apparatus according to the embodiment of the present invention.

  Hereinafter, the combustion apparatus of the present embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a schematic side view showing an example of a gas burner and a nozzle manifold according to an embodiment of the present invention, FIG. 2 is a schematic plan view showing an example of a gas burner according to an embodiment of the present invention, and FIG. 1 is a schematic diagram showing an example of a combustion apparatus according to an embodiment of the invention.

  As shown in FIGS. 1 and 2, the combustion apparatus of the present embodiment includes a plurality (16 in the present embodiment) of gas burners 1 as a combustion section, and a gas supply for supplying fuel gas to these gas burners 1. Means 2 are provided.

  Each of the gas burners 1 has a flat and identical shape, and is a so-called light and dark burner in which a pair of upper and lower gas inlets 3 and 4 are open as shown in FIG. A concentrated gas flow path 5 through which the gas-rich mixture flows is continuously formed downstream of the upper gas introduction port 3, and a light gas flow path 6 through which the air-rich mixture flows flows downstream of the lower gas introduction port 4. It is formed continuously. As shown in FIG. 2, the gas burners 1 are arranged in one direction adjacent to each other to constitute one combustion unit 7.

  As shown in FIG. 1, the gas supply means 2 includes a nozzle manifold 8 and an electromagnetic valve 9 for supplying fuel gas to each nozzle chamber 15 defined by partition walls (not shown). The nozzle manifold 8 includes two upper and lower nozzles 12 and 13, and a plurality of nozzles 12 and 13 are provided along the arrangement direction of the gas burners 1 corresponding to the gas burners 1. The upper nozzle 12 is a deep nozzle facing the upper gas inlet 3 connected to the rich gas flow path 5 of each gas burner 1, and has a jet nozzle diameter that is relatively small. The lower nozzle 13 is a light nozzle facing the lower gas inlet 4 connected to the light gas flow path 6 of each gas burner 1, and the diameter of the nozzle is larger than the diameter of the nozzle of the upper nozzle 12. The fuel gas ejected from the nozzles 12 and 13 facing each other is introduced into the upper and lower gas inlets 3 and 4 of each gas burner 1, and at this time, the primary air for combustion is also sucked together by the ejector effect. The

  Further, gas flow holes 21 are formed below the nozzle manifold 8, and the gas flow holes 21 are opened and closed on the upstream side of the gas flow holes 21 via the solenoid valve mounting portions 27 of the nozzle manifold 8. A solenoid valve 9 is attached. Each solenoid valve mounting portion 27 is hollow and communicates with the gas supply pipe 30 shown in FIG.

  FIG. 3 is a schematic diagram showing an example of the combustion apparatus of the present embodiment. As shown in the figure, a can 10 is accommodated in the casing 100. The can 10 contains the heat exchanger 40, the gas burner 1 described above for heating the heat exchanger 40, and the nozzle manifold 8.

  A combustion fan 50 for supplying combustion air into the can body 10 is connected to a part of the bottom wall of the can body 10, and is rotated by a motor M. An exhaust port 60 for discharging combustion exhaust gas to the outside of the casing 100 is formed at the upper end of the can body 10, and the exhaust port 60 and the inside of the can body 10 communicate with each other through an exhaust path 61. A gas supply pipe 30 for supplying fuel gas to the nozzle manifold 8 passes through the bottom wall of the can 10 on the upstream side, and fuel gas is supplied to the gas supply pipe 30 by a signal from the control unit C. A gas proportional valve 71 and an original gas electromagnetic valve 72 for turning on / off the gas are disposed.

  The heat exchanger 40 is disposed above the gas burner 1 in the can 10, and a water supply pipe 81 and a hot water discharge pipe 82 are connected to the heat exchanger 40. Although not shown, the water supply pipe 81 is provided with a water flow sensor, and the hot water discharge pipe 82 is provided with a hot water temperature thermistor. Thereby, for example, when a hot water supply terminal such as a curan is opened and a water flow is detected by a water flow sensor provided in the water supply pipe 81, the combustion fan 50 is rotated, and the original gas solenoid valve 72 and the gas proportional valve are rotated. 71 and the solenoid valve 9 are opened to ignite the gas burner 1, whereby the fuel gas is combusted and a combustion operation for heating the heat exchanger 40 with combustion heat is started. Then, the number of revolutions of the combustion fan 50 and the amount of fuel gas supplied are adjusted so that the temperature of the hot water detected by the hot water temperature thermistor becomes a predetermined temperature, and the combustion of the gas burner 1 is controlled.

  An outside air temperature thermistor (outside air temperature detector) 90 for detecting the outside air temperature is disposed on the side wall of the casing 100, and the detected outside air temperature signal is output to the control unit C. The control unit C includes a CPU, a ROM, and a RAM. As a functional component, the control unit C includes a combustion operation control unit that controls the combustion operation and a post purge operation control unit that performs the post purge operation after the combustion operation. It is electrically connected to the solenoid valve 9, the gas proportional valve 71, the original gas solenoid valve 72, the motor M, the outside air temperature thermistor 90, the water flow sensor, the hot water temperature thermistor, and the like.

  Since the amount of combustion exhaust gas discharged in the post-purge operation is determined by the operation time and operation flow rate (operation time × operation flow rate) of the combustion fan 50, the post-purge discharge air amount is set by using these as setting elements. be able to. In the present embodiment, since the post-purge discharge air volume is set according to the outside air temperature, the combustion time of the gas burner 1, etc., the rotational speed of the combustion fan 50 during the post-purge operation is fixed to the minimum rotational speed, and after the combustion is stopped. Post purge operation time is changed. Therefore, the post-purge operation control unit stores the data table for setting the initial post-purge operation time and the post-purge operation time according to the outside air temperature, the current combustion time and the combustion time after the end of the combustion operation Combustion time storage unit for accumulating and storing the total combustion time of the gas burner 1 within a retroactive time retroactive from the stop, the outside air temperature, the combustion time of the gas burner 1, and the gas burner 1 within a retroactive time retroactive to the combustion stop A post-purge operation time determination unit that determines the post-purge operation time based on the total combustion time, a timer unit, and the like. Note that the rotational speed of the combustion fan 50 and the initial post-purge operation time during the post-purge operation are the internal volume of the device, the capacity of the combustion fan 50, the length of the exhaust passage 61 to the exhaust port 60, and the like. It is determined appropriately according to the configuration.

  Next, the control operation when the post-purge operation is performed after the combustion operation in the combustion apparatus of the present embodiment will be described with reference to the control flow of FIG. In the combustion apparatus of the present embodiment, the post-purge operation is programmed every time after the combustion operation.

  When the original gas solenoid valve 72, the gas proportional valve 71, and the solenoid valve 9 are closed by the signal from the control unit C, the supply of the fuel gas is stopped, and the combustion of the gas burner 1 is stopped, the control unit C First, while reducing the rotation speed of the combustion fan 50 to the minimum rotation speed, a timer is started (ST1), and the outside air temperature detected by the outside air temperature thermistor 90 is equal to or higher than the first determination temperature (for example, 15 ° C.). It is determined whether or not there is (ST2). If the outside air temperature is equal to or higher than the first determination temperature (Yes in ST2), the control unit C rotates the combustion fan 50 until the initial post-purge operation time (for example, 15 seconds) elapses after the combustion is stopped. After performing the purge operation (ST8), the combustion fan 50 is stopped (ST9). That is, when the outside air temperature is high, the surface temperature of the nozzles 12 and 13 is high and it is difficult for dew condensation to occur. Therefore, dew condensation can be effectively prevented by performing a short time post purge operation.

  If the outside air temperature is lower than the first determination temperature (No in ST2), the control unit C determines whether or not the current combustion time of the gas burner 1 is equal to or longer than a first determination time (for example, 2 minutes). (ST3). That is, if the gas burner 1 burns for a certain time or longer, the surfaces of the nozzles 12 and 13 of the nozzle manifold 8 that supplies the fuel gas to the gas burner 1 also rise in temperature due to heat transfer. Condensation is unlikely to occur. Therefore, if the post purge operation time is set based on both the outside air temperature and the combustion time of the gas burner 1, the post purge operation can be performed efficiently. For this reason, even if the outside air temperature is lower than the first determination temperature, if the combustion time of the gas burner 1 is equal to or longer than the first determination time (No in ST2, Yes in ST3), the combustion fan 50 is in the initial post-purge operation. A post-purge operation is performed for rotation over time (ST8).

  On the other hand, when the outside air temperature is less than the first determination temperature and the combustion time of the gas burner 1 is less than the first determination time (No in ST2, No in ST3), the control unit C is further constant from the current combustion stop. It is determined whether or not the total combustion time of the gas burner 1 within a retroactive time retroactive to time (for example, 10 minutes) is equal to or longer than a second determination time (for example, 5 minutes) (ST4). That is, even if the current combustion operation is completed in a short time, the surface of the nozzles 12 and 13 of the nozzle manifold 8 is warmed if the combustion operation has been performed for a certain period of time or more recently. Condensation is unlikely to occur even when the temperature is low. Therefore, if the post purge operation time is set in consideration of not only the current combustion operation but also the combustion operation performed so far, dew condensation can be prevented more efficiently. For this reason, even if the outside air temperature is less than the first determination temperature and the current combustion time of the gas burner 1 is less than the first determination time, the latest combustion time of the gas burner 1 is not less than the second determination time ( In ST2, No, in ST3, No, in ST4, Yes), a post-purge operation for rotating the combustion fan 50 for the initial post-purge operation time is performed (ST8).

  On the other hand, when the outside air temperature is less than the first determination temperature, the current combustion time of the gas burner 1 is less than the first determination time, and the total combustion time of the latest gas burner 1 is also less than the second determination time (ST2). No, in ST3, No, in ST4, No), there is a high possibility that condensation will occur on the surfaces of the nozzles 12 and 13 of the nozzle manifold 8. For this reason, since the control part C sets post purge operation time according to external temperature, it is first determined whether external temperature is less than 1st determination temperature and 2nd determination temperature (for example, 10 degreeC) or more. (ST5).

  If the outside air temperature is lower than the first determination temperature and equal to or higher than the second determination temperature (Yes in ST5), the control unit C burns the first post purge operation time (for example, 60 seconds) longer than the initial post purge operation time. The combustion fan 50 is rotated until it elapses from the stop (ST6). Further, if the outside air temperature is lower than the second determination temperature (No in ST5), the control unit C determines that the second post purge operation time (for example, 240 seconds) longer than the first post purge operation time has elapsed since the combustion stop. The combustion fan 50 is rotated until it is done (ST7). As described above, when the outside air temperature is low and the combustion time and the total combustion time of the gas burner 1 are short and condensation easily occurs, the post-purge operation time of the combustion fan 50 is set longer as the outside air temperature decreases. Thus, condensation can be reliably prevented.

(Other embodiments)
(1) In the above embodiment, the post-purge operation time of the combustion fan 50 is set based on the outside air temperature and the combustion time of the gas burner 1. However, instead of or in addition to the combustion time of the gas burner 1, combustion in the apparatus is performed. The post-purge operation time may be set by directly detecting the exhaust gas residue. That is, an internal temperature thermistor (internal temperature detection unit) that detects the temperature near the nozzle, an exhaust temperature thermistor (exhaust temperature detection unit) that detects the temperature of the combustion exhaust gas near the exhaust port, and a carbon monoxide concentration in the apparatus. At least one detection unit selected from the group consisting of a CO sensor (carbon monoxide concentration detection unit), a nozzle vicinity temperature detected by an internal temperature thermistor, a temperature of combustion exhaust gas detected by an exhaust temperature thermistor, and The post purge operation time of the combustion fan 50 may be set based on at least one detection result selected from the group consisting of the carbon monoxide concentration detected by the CO sensor. According to the combustion apparatus, although another detection means is required, dew condensation can be prevented more reliably when the backflow of the combustion exhaust gas occurs.

  FIG. 5 shows a control operation when the post purge operation is performed after the combustion operation in the combustion device that sets the post purge operation time based on the nozzle vicinity temperature instead of the combustion time of the gas burner 1. Note that the steps (ST21 to ST22 and ST27 to ST28) for performing the initial post-purge operation time and the post-purge operation when the outside air temperature is equal to or higher than the first determination temperature after the combustion is stopped are the steps described in FIG. 4 (ST1 ˜ST2 and ST8˜ST9), only different parts will be described.

  When the outside air temperature is lower than the first determination temperature (No in ST22), the control unit C determines whether the nozzle vicinity temperature detected by the internal temperature thermistor is equal to or higher than the first nozzle determination temperature (for example, 15 ° C.). Is determined (ST23). Then, even if the outside air temperature is lower than the first determination temperature, the control unit C initializes the combustion fan 50 if the nozzle vicinity temperature is equal to or higher than the first nozzle determination temperature (No in ST22, Yes in ST23). A post purge operation is performed for the post purge operation time (ST27). That is, if the temperature in the vicinity of the nozzle is increased by burning the gas burner 1 for a certain period of time, condensation is unlikely to occur even if the outside air temperature is low, so the combustion fan 50 is rotated for a short initial post-purge operation time. Thus, the post-purge operation can be performed efficiently.

  On the other hand, when the outside air temperature is lower than the first determination temperature and the nozzle vicinity temperature is lower than the first nozzle determination temperature (No in ST22, No in ST23), the surfaces of the nozzles 12 and 13 of the nozzle manifold 8 are used. There is a high possibility of condensation. Therefore, the control unit C determines whether the nozzle vicinity temperature is lower than the first nozzle determination temperature and equal to or higher than the second nozzle determination temperature (for example, 10 ° C.) (ST24).

  If the outside air temperature is lower than the first nozzle determination temperature and equal to or higher than the second nozzle determination temperature (Yes in ST24), the controller C has a first post purge operation time (for example, 60 seconds) longer than the initial post purge operation time. The combustion fan 50 is rotated until after the combustion has stopped (ST25). If the outside air temperature is lower than the second nozzle determination temperature (No in ST24), the control unit C determines that the second post-purge operation time (for example, 240 seconds) longer than the first post-purge operation time is from the combustion stop. The combustion fan 50 is rotated until it elapses (ST26). Thereby, dew condensation can be reliably prevented.

  In FIG. 5, the post-purge operation time is set based on the outside air temperature and the temperature in the vicinity of the nozzle. However, the post-purge operation time may be similarly set based on the temperature of the combustion exhaust gas and the carbon monoxide concentration. Good. Moreover, you may combine the combustion time of the gas burner 1 already mentioned, and these detection results.

(2) In the above embodiment, the post-purge operation flow rate of the combustion fan 50 is fixed and the post-purge operation time is changed in setting the post-purge discharge air volume, but the post-purge operation time is fixed and the outside air temperature is changed. Depending on the combustion time of the gas burner 1, the post purge operation flow rate of the combustion fan 50 may be changed, or both the post purge operation time and the post purge operation flow rate of the combustion fan 50 may be changed. However, in order to increase the post-purge discharge air volume, the post purge operation time is set longer than the increase in the post-purge operation flow rate by increasing the rotational speed of the combustion fan 50, so that the same amount of post-purge discharge air volume is set. Even in this case, combustion exhaust gas is efficiently discharged, and condensation can be prevented. Further, by operating the combustion fan 50 at a low rotational speed, noise during post-purge operation can be reduced.

1 Gas burner 8 Nozzle manifold 12, 13 Nozzle 50 Combustion fan 90 Outside temperature thermistor (outside temperature detector)
C control unit

Claims (7)

A gas burner for burning the fuel gas supplied from the nozzle manifold;
A combustion fan for supplying combustion air to the gas burner;
An outside air temperature detector for detecting outside air temperature,
An exhaust passage for discharging exhaust gas generated by combustion of the gas burner from an exhaust port communicating with the outdoors;
A control unit that controls a post-purge operation of a combustion fan for discharging the combustion exhaust gas after the combustion of the gas burner is stopped,
The said control part is a combustion apparatus which sets the post-purge discharge | emission air volume of the said combustion fan based on the external temperature detected by the said external temperature detection part. The combustion apparatus according to claim 1, wherein
The said control part is a combustion apparatus which sets the said post purge exhaust air volume further based on the combustion time of the said gas burner. The combustion apparatus according to claim 1 or 2,
The setting of the post-purge exhaust air volume is a combustion apparatus that is set by a post-purge operation time of the combustion fan and / or a post-purge operation flow rate of the combustion fan. The combustion apparatus according to claim 3,
The controller sets the post-purge operation time of the combustion fan when the outside air temperature detected by the outside air temperature detection unit is equal to or higher than a first determination temperature as the initial post-purge operation time when setting the post-purge discharge air volume. Set,
Even if the outside air temperature detected by the outside air temperature detecting unit is lower than the first determination temperature, if the combustion time of the gas burner is equal to or longer than the first determination time, the post purge operation time of the combustion fan is set to the initial post purge. Set the operation time
If the outside air temperature detected by the outside air temperature detection unit is less than the first determination temperature and the combustion time of the gas burner is less than the first determination time, the post-purge operation time of the combustion fan is set from the initial post-purge operation time. Combustion device that is set longer. The combustion apparatus according to claim 4, wherein
The control unit has a retroactive time that is a predetermined time after the combustion stop even if the outside air temperature detected by the outside air temperature detecting unit is less than the first determination temperature and the combustion time of the gas burner is less than the first determination time. When the total combustion time of the gas burner is equal to or longer than the second determination time, the post purge operation time of the combustion fan is set to the initial post purge operation time,
The outside combustion temperature detected by the outside air temperature detection unit is less than the first determination temperature, the combustion time of the gas burner is less than the first determination time, and further, the total combustion of the gas burner within a retroactive time that is a certain time retroactive from the combustion stop A combustion apparatus that sets a post purge operation time of the combustion fan longer than the initial post purge operation time when the time is less than a second determination time. The combustion apparatus according to any one of claims 3 to 5,
In the setting of the post-purge discharge air volume, the control unit sets the post-purge operation time of the combustion fan longer as the outside air temperature decreases. The combustion apparatus according to any one of claims 3 to 6, further comprising an internal temperature detection unit that detects the temperature in the vicinity of the nozzle, an exhaust temperature detection unit that detects the temperature of the combustion exhaust gas in the vicinity of the exhaust port, and the inside of the apparatus Having at least one detection unit selected from the group consisting of carbon monoxide concentration detection units for detecting the carbon monoxide concentration,
The control unit includes a nozzle vicinity temperature detected by the internal temperature detection unit, a combustion exhaust gas temperature detected by the exhaust temperature detection unit, and a carbon monoxide concentration detected by the carbon monoxide concentration detection unit. A combustion apparatus that sets a post-purge operation time of the combustion fan based on at least one detection result selected from a group.

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