JP2017172833A - Heat source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat efficiency while suppressing dew condensation in a nozzle after a burner is extinguished.SOLUTION: A fuel gas jetted from a nozzle is allowed to combust in a burner, and a heating medium is heated by a heat exchanger for exchanging heat with combustion exhaust. Also, a scavenging operation is executed for maintaining air blowing of a combustion fan for delivering combustion air to the burner for predetermined time after the burner is extinguished. Temperature control of the heating medium is performed by controlling a supply amount of the fuel gas to the burner, and when the temperature of the heating medium exceeds a predetermined temperature, intermittent combustion control is executed for repeating extinguishment and combustion of the burner so as to maintain the temperature. Then, in the case where the burner is extinguished by the intermittent combustion control, execution time of the scavenging operation is made to be shorter than the predetermined time. Thereby, by the scavenging operation for the predetermined time, the combustion exhaust is exhausted and occurrence of dew condensation can be suppressed. Also, during the intermittent combustion control, as the nozzle is sufficiently heated and dew condensation hardly occurs, cooling of the heat exchanger can be suppressed by shortening the scavenging operation, and heat efficiency can be improved.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a heat source device that performs a scavenging operation in which combustion exhaust is discharged by blowing air from a combustion fan after extinguishing a burner.

  2. Description of the Related Art A heat source device that supplies heat used for heating or hot water supply via a heat medium such as warm water is known. The heat source device includes a burner that burns the fuel gas injected from the nozzle, a combustion fan that sends combustion air toward the burner, a heat exchanger that heats the heat medium by heat exchange with the combustion exhaust from the burner, etc. It is possible to adjust the temperature of the heating medium by changing the heating power (generated heat amount) by controlling the amount of fuel gas supplied to the burner. Further, when the temperature of the heating medium exceeds a predetermined temperature even if the heating power of the burner is minimized, the temperature of the heating medium is maintained by intermittent combustion control in which the burning of the burner is repeated and combustion is repeated.

  In such a heat source device, post-purge (scavenging operation) is performed after the burner is extinguished while maintaining the ventilation of the combustion fan (for example, Patent Document 1). This is because, after the burner is extinguished, the warm and moist combustion exhaust gas remains in the system without being discharged, causing condensation and blocking the nozzle, which may cause ignition failure during the next combustion. Yes, by performing the post purge, the combustion exhaust is discharged to the outside from the exhaust port. Especially in situations where condensation tends to occur, such as when the outside air temperature is low, the occurrence of condensation is suppressed by ensuring a long post purge time.

JP2013-242096A

  However, when the post purge becomes longer, the burner and the heat exchanger in the heat source device are cooled, so that there is a problem that the heat efficiency is greatly lowered in maintaining the temperature of the heat medium.

  The present invention has been made in response to the above-described problems in the prior art, and it is possible to improve the thermal efficiency of maintaining the temperature of the heating medium while suppressing the occurrence of condensation at the nozzle after extinguishing the burner. An object is to provide a heat source device.

In order to solve the above-described problems, the heat source device of the present invention employs the following configuration. That is,
A burner for burning the fuel gas injected from the nozzle;
A combustion fan for sending combustion air toward the burner;
A heat exchanger that heats the heat medium by heat exchange with the combustion exhaust from the burner;
A combustion control unit that controls the amount of the fuel gas supplied to the burner to adjust the temperature of the heating medium;
An exhaust port for discharging the combustion exhaust gas that has passed through the heat exchanger to the outside;
A scavenging control unit for controlling the execution of a scavenging operation for discharging the combustion exhaust gas from the exhaust port by maintaining the ventilation of the combustion fan for a predetermined time after extinguishing the burner, and through the heat medium In the heat source device that supplies heat,
When the temperature of the heating medium exceeds a predetermined temperature, the combustion control unit can perform intermittent combustion control that repeats extinguishing and burning of the burner so as to maintain the temperature of the heating medium.
When the burner is extinguished by the intermittent combustion control, the scavenging control unit makes the execution time of the scavenging operation shorter than the predetermined time.

  In such a heat source device of the present invention, the burner may be extinguished before the nozzle is warmed by combustion of the burner. In such a case, condensation may occur at the nozzle, so the scavenging operation is performed for a predetermined time. By sufficiently discharging the combustion exhaust from the exhaust port, it is possible to suppress the occurrence of condensation at the nozzle. However, when the burner is extinguished by the intermittent combustion control, the nozzle is sufficiently warmed up until the temperature of the heat medium exceeds a predetermined temperature, and condensation is unlikely to occur. In the intermittent combustion control, even if the burner is extinguished, the combustion of the burner is scheduled to resume after that. By shortening the execution time of the scavenging operation from a predetermined time, the scavenging operation (combustion) Cooling of the heat exchanger or the like due to fan blowing can be reduced, and as a result, the thermal efficiency for maintaining the temperature of the heat medium can be improved.

  The heat source device of the present invention described above may be configured as follows. First, an outside air temperature sensor that detects the outside air temperature is provided, and if the detected temperature of the outside air temperature sensor is equal to or higher than the reference value, the scavenging operation is executed for the first predetermined time, whereas the detected temperature of the outside air temperature sensor is When the value is lower than the reference value, the scavenging operation is executed for a second predetermined time longer than the first predetermined time. When the burner is extinguished by the intermittent combustion control, even if the detected temperature of the outside air temperature sensor is lower than the reference value, the execution time of the scavenging operation is shorter than the second predetermined time and the first predetermined Set it equal to or greater than the time.

  In such a heat source device of the present invention, it is first determined whether or not the nozzle is likely to cause condensation based on the outside air temperature. If the outside air temperature is lower than the reference value and condensation is likely to occur, scavenging operation is performed. The occurrence time of dew condensation can be suppressed by extending the execution time from the first predetermined time to the second predetermined time. However, even if the outside air temperature is lower than the reference value, if the burner is extinguished by intermittent combustion control, it is difficult for condensation to occur because the nozzle is sufficiently warm, so the scavenging operation execution time is (2) By not extending the predetermined time or making it shorter than the second predetermined time, cooling of the heat exchanger or the like by the scavenging operation (burning of the combustion fan) is suppressed, and the heat efficiency for maintaining the temperature of the heat medium is improved. Can do.

It is explanatory drawing which showed the structure of the heat-source apparatus 1 of a present Example which supplies the heat for heating via a heat medium. It is explanatory drawing which showed the structure of the manifold 120 and the burner 110 which were mounted in the combustion unit 100 of a present Example. It is explanatory drawing which showed the example which controls combustion of the burner 110 and supplies heat to the heating terminal 300 via a heat medium. It is a flowchart of the scavenging control process which the control part 150 of a present Example performs. It is a flowchart of the scavenging control process which the control part 150 of a modification is performed. It is explanatory drawing which showed the example which supplies the heat for hot water supply with the heat source apparatus.

  FIG. 1 is an explanatory diagram showing a configuration of a heat source device 1 of the present embodiment that supplies heat for heating via a heat medium. First, in the combustion unit 100 that generates heat by the combustion of fuel gas, a plurality of (eight in the illustrated example) burners 110 housed in the combustion chamber 102 and a plurality of nozzles 122 project toward the burner 110. In addition, a manifold 120 that distributes fuel gas to each nozzle 122, a gas flow path 130 for supplying fuel gas to the manifold 120, and the like are provided.

  The gas flow path 130 is provided with a main valve 132 that opens and closes the gas flow path 130 and a proportional valve 134 that adjusts the flow rate of the fuel gas that passes through the gas flow path 130 on the downstream side of the main valve 132. . Further, in the combustion unit 100 of the present embodiment, two gas flow paths 130 are provided on the downstream side of the proportional valve 134, corresponding to the fact that a plurality (eight) burners 110 are divided into two burner groups. The first switching valve 136a that opens and closes the branch path corresponding to the first burner group constituted by the three burners 110 and the second burner group constituted by the five burners 110 are branched. And a second switching valve 136b that opens and closes the branch path.

  The amount of generated heat (heating capacity) can be switched depending on which burner group is supplied with fuel gas by controlling the opening and closing of these two switching valves 136a and 136b. For example, when the amount of heat required is the maximum, both the two switching valves 136a and 136b are opened. On the other hand, when the amount of heat required is the minimum, only the first switching valve 136a is opened. When the intermediate amount of heat is required, only the second switching valve 136b is opened.

  Also, in the combustion chamber 102, a combustion fan 140 that sends combustion air from below toward the burner 110, a spark plug 142 that blows a spark by high-voltage discharge, and ignition (flame) in the burner 110 are detected. Frame rods that are not used are provided. Furthermore, the heat source device 1 is equipped with a control unit 150 that controls combustion, and the main valve 132, the proportional valve 134, the two switching valves 136a and 136b, the combustion fan 140, the spark plug 142, and the frame rod are controlled. Connected to the unit 150. In addition, the control part 150 of a present Example is corresponded to the "combustion control part" of this invention.

  A first heat exchanger 200 is provided above the combustion chamber 102, and a second heat exchanger 202 is provided above the first heat exchanger 200, and the first heat exchanger 200 is provided. And the second heat exchanger 202 are connected by a communication passage 204. The communication passage 204 is provided with a circulation pump 206, and the circulation pump 206 is connected to the control unit 150. In addition, a circulation circuit 208 that circulates hot water as a heat medium between the first heat exchanger 200 and the second heat exchanger 202 and the heating terminal 300 such as floor heating is provided, and the first heat exchanger 200 is provided. Is connected to the forward passage 208 a of the circulation circuit 208, and the return passage 208 b of the circulation circuit 208 is connected to the second heat exchanger 202. In the heat source device 1 of the present embodiment, hot water is used as the heat medium circulating in the circulation circuit 208, but is not limited to hot water, and silicone oil or the like may be used.

  The control unit 150 drives the circulation pump 206 and controls the combustion fan 140, the main valve 132, the proportional valve 134, the two switching valves 136a and 136b, the spark plug 142, and the like to start combustion in the burner 110. . The heat medium circulated by the operation of the circulation pump 206 is heated by the sensible heat exchange with the combustion exhaust of the burner 110 in the first heat exchanger 200, and the heat medium having reached a high temperature passes through the outgoing passage 208a and is a heating terminal. 300. In the heating terminal 300, the surroundings are warmed by dissipating heat while passing through a meandering pipe or the like. Then, the heat medium cooled by passing through the heating terminal 300 is sent to the second heat exchanger 202 through the return passage 208b.

  In the second heat exchanger 202, latent heat is recovered from the combustion exhaust of the burner 110, and the heat medium is preheated with the recovered heat. Thus, after preheating, the heating medium is returned to the first heat exchanger 200 through the communication passage 204 and heated again. In addition, a heat medium temperature sensor 210 is installed at the end on the first heat exchanger 200 side in the outgoing passage 208a, and the temperature of the heat medium flowing out from the first heat exchanger 200 can be detected. is there. The heat medium temperature sensor 210 is connected to the control unit 150.

  An exhaust port 230 is provided above the second heat exchanger 202. The combustion exhaust from the burner 110 is sent upward by the blow of the combustion fan 140, passes through the first heat exchanger 200 and the second heat exchanger 202, and is then discharged from the exhaust port 230 to the outside of the heat source device 1. Further, as described above, as the latent heat is recovered from the combustion exhaust gas by the second heat exchanger 202, the steam contained in the combustion exhaust gas is condensed and drain drainage is generated. Therefore, a drain receiver 220 that receives drain water is provided below the second heat exchanger 202. Then, the acidic drain drainage accumulated in the drain receiver 220 is neutralized by the neutralizer 224 connected to the drain pipe 222 and then discharged to the outside.

  FIG. 2 is an explanatory view showing the structure of the manifold 120 and the burner 110 mounted on the combustion unit 100 of the present embodiment. First, FIG. 2A shows a perspective view of the manifold 120 viewed from the burner 110 side. The manifold 120 of the present embodiment is formed by combining two plate-like members, and on the surface on the burner 110 side, a pair of nozzles 122 projecting toward the burner 110 are arranged in the same number as the burner 110. In the embodiment, 8 sets) are provided. At the tips of these nozzles 122, nozzle holes 122h are opened. Also, below the nozzle 122, the two switching valves 136a and 136b described above that switch opening and closing of the branch of the gas flow path 130 are provided.

  Further, as shown in FIG. 2A, the burner 110 according to the present embodiment is formed by combining a pair of plate-like members, and has a flat shape. The burner 110 has a flame port 112 at the upper end and a pair of upper and lower gas inlets 114 at the end on the manifold 120 side, and is formed between the pair of plate-like members. The gas inlet 114 and the flame port 112 are connected by the mixing passage 116. When the manifold 120 and the burner 110 are installed in the combustion unit 100, the pair of upper and lower nozzles 122 of the manifold 120 and the pair of upper and lower gas inlets 114 of the burner 110 are arranged to face each other. In FIG. 2A, only one burner 110 is illustrated, but a burner 110 corresponding to each of a pair of upper and lower nozzles 122 is provided.

  FIG. 2B shows a cross-sectional view of the manifold 120 cut along a plane parallel to the burner 110. As shown in the figure, a distribution passage 126 is formed between two plate-like members of the manifold 120. In the combustion unit 100 of this embodiment, two distributions corresponding to the two burner groups described above are performed. A passage 126 is formed. Each distribution passage 126 communicates with the gas flow path 130 via the gas flow holes 124, and the two switching valves 136a and 136b described above open and close the corresponding gas flow holes 124. Therefore, the distribution passage 126 for supplying the fuel gas can be changed by controlling the opening and closing of the two switching valves 136a and 136b.

  The plurality of nozzles 122 communicate with the distribution passage 126, and when the switching valve 136 is opened, the fuel gas flowing in from the gas circulation hole 124 is supplied to the nozzle 122 through the distribution passage 126. When the fuel gas is ejected from the nozzle 122, the fuel gas flows into the gas inlet 114 of the burner 110 while sucking the combustion air, and the fuel gas and the combustion air passing through the mixing passage 116 are mixed together, and the upper end of the burner 110 is mixed. Combustion of the mixed gas is performed at the flame port 112 of the part.

  FIG. 3 is an explanatory view showing an example in which the combustion of the burner 110 is controlled and heat is supplied to the heating terminal 300 via the heat medium. In the graph of FIG. 3A, the horizontal axis represents time and the vertical axis represents temperature, and the change in temperature detected by the heat medium temperature sensor 210 accompanying the combustion control of the burner 110 (temperature change of the heat medium) is shown. ing. Further, in correspondence with the time of FIG. 3 (a), FIG. 3 (b) schematically shows a state of switching between burning and extinguishing of the burner 110, and FIG. 3 (c) shows the combustion. The manner in which the fan 140 is switched between operation and stop is schematically shown.

  First, when the user of the heat source device 1 (heating terminal 300) turns on an operation switch (not shown), the control unit 150 activates the circulation pump 206 and the combustion fan 140, and the main valve 132, the proportional valve 134, and the switching valve 136. And the combustion is started in the burner 110 by sparking with the spark plug 142. In the illustrated example, since the temperature of the heat medium at the start of operation is low (equal to the outside air temperature), both of the two switching valves 136a and 136b are opened to quickly heat the heat medium, and the amount of heat generated by the burner 110 is reduced. The heating medium is heated to a maximum (combusted by eight burners 110).

  Then, when the temperature of the heat medium approaches the target temperature (for example, 60 degrees) corresponding to the set temperature of the heating terminal 300, the first switching valve 136a is closed and the second switching valve 136b to suppress the generated heat amount of the burner 110. Only the first switching valve 136a is opened and the second switching valve 136b is closed to minimize the amount of heat generated by the burner 110 (combustion by the three burners 110). To do.

  In this way, even if the amount of heat generated by the burner 110 is minimized, if the amount of heat is too large to keep the heat medium warm and overheated, the temperature of the heat medium becomes a fire extinguishing temperature higher than the target temperature (for example, 70 degrees). Once reached, the burner 110 is extinguished once. The burner 110 is extinguished by closing at least one of the main valve 132, the proportional valve 134, and the switching valve 136. Thereafter, when the temperature of the heat medium is lowered to an ignition temperature (for example, 50 degrees) lower than the target temperature, combustion in the burner 110 is resumed. At this time, the heat medium is heated by minimizing the amount of heat generated by the burner 110. In this way, by performing intermittent combustion control in which the burner 110 is repeatedly extinguished and burned, the temperature of the heat medium can be maintained near the target temperature.

  In such a heat source device 1, after the burner 110 is extinguished, the nozzle hole 122 h may be blocked by water droplets due to condensation in the manifold 120, and fuel gas is injected from some of the plurality of nozzles 122 during the next combustion. Failure to do so results in poor ignition at the corresponding burner 110. Such condensation is caused by the fact that warm and moist combustion exhaust is not discharged from the exhaust port 230. As described above, in the heat source device 1 that recovers latent heat from the combustion exhaust by the second heat exchanger 202, strong wind is generated at the exhaust port 230. When sprayed, dew condensation is likely to occur at the nozzle 122 of the manifold 120 due to the backflow of the combustion exhaust gas containing a large amount of moisture through the drain receiver 220 in which warm drain water is accumulated. In addition, after the combustion is started in the burner 110 when the operation of the heat source device 1 is started, before the manifold 120 is sufficiently warmed, the user turns off the operation switch of the heat source device 1 (heating terminal 300) or the like. When fire is extinguished, condensation is particularly likely to occur.

  As a countermeasure against such condensation, the heat source device 1 generally performs post-purge (also referred to as scavenging operation) while maintaining the blowing of the combustion fan 140 after the burner 110 is extinguished (see FIG. 3C). . If a long post purge time is secured, the combustion exhaust gas is easily discharged from the exhaust port 230, so that the occurrence of condensation can be suppressed. On the other hand, if the post purge becomes longer, the burner 110, the first heat exchanger 200, and the second heat exchanger 202 are cooled by the blowing of the combustion fan 140, so in maintaining the temperature of the heat medium, In the above-described intermittent combustion control, the timing at which the temperature of the heat medium is lowered to the ignition temperature (restarting combustion of the burner 110) is advanced, and the thermal efficiency is greatly reduced. Therefore, in the heat source device 1 of the present embodiment, in order to improve the thermal efficiency for maintaining the temperature of the heating medium while suppressing the occurrence of condensation at the nozzle 122 after the burner 110 is extinguished, the control unit 150 is configured as follows. The scavenging control process is being executed.

  FIG. 4 is a flowchart of the scavenging control process executed by the control unit 150 of the present embodiment. This scavenging control process is a process that is executed when the burner 110 is extinguished in the combustion control process of the burner 110. In addition, the control part 150 of a present Example is corresponded to the "scavenging control part" of this invention. In the scavenging control process, first, the scavenging operation is started by continuing the blowing of the combustion fan 140 in operation (STEP 100). As described above, the combustion fan 140 is operating during the combustion of the burner 110, and the amount of air blown (the number of rotations) of the combustion fan 140 is adjusted so that the fuel gas and the combustion air have an appropriate ratio (air-fuel ratio). Is set. On the other hand, the blown amount of the combustion fan 140 during the scavenging operation is set to be equal to the blown amount when the generated heat amount of the burner 110 is the minimum.

  When the scavenging operation is thus started, it is determined whether or not the burner 110 is extinguished due to the fact that the temperature of the heat medium has reached the extinguishing temperature (STEP 102). As described above, the fire extinguishing of the burner 110 is performed when the operation switch of the heat source device 1 (heating terminal 300) is turned off or the temperature of the heat medium (the temperature detected by the heat medium temperature sensor 210) reaches the fire extinguishing temperature. Then, when the burner 110 is extinguished by turning off the operation switch (STEP 102: no), it is not due to the temperature of the heat medium reaching the extinguishing temperature (STEP 102: no). The scavenging time is set to a predetermined time (STEP 104). This predetermined time is sufficient to discharge the warm and humid combustion exhaust gas from the exhaust port 230 and to reduce the temperature of the warm drainage drainage accumulated in the drain receiver 220 and its surroundings (suppressing the backflow containing a lot of moisture). The time is set to 3 minutes, for example. The predetermined time is set according to the internal volume from the burner 110 to the exhaust port 230 of the heat source device 1 and the blowing capacity of the combustion fan 140.

  On the other hand, when the burner 110 is extinguished because the temperature of the heat medium reaches the extinguishing temperature (STEP 102: yes), the scavenging time is set to a time shorter than the predetermined time (STEP 106). The scavenging operation not only discharges combustion exhaust from the exhaust port 230 but also releases the fuel gas remaining in the combustion chamber 102 to prevent explosive ignition at the next ignition, or burns immediately after the burner 110 is extinguished. Since it is also necessary to prevent partial overheating of the first heat exchanger 200 due to the stagnation of exhaust (after-boiling), the time is shorter than the predetermined time. Is set to a sufficient time, for example, 10 seconds.

  When the scavenging time is thus set, it is determined whether or not the scavenging time has elapsed since the burner 110 was extinguished (STEP 108). If the scavenging time has not elapsed (STEP 108: no), the process waits until the scavenging time has elapsed. Thereafter, when the scavenging time has elapsed (STEP 108: yes), the scavenging operation is terminated by stopping the combustion fan 140 (STEP 110), and the scavenging control process of FIG. 4 is also terminated.

  As described above, in the heat source device 1 of the present embodiment, when the operation switch is turned off and the burner 110 is extinguished, the manifold 120 may not be sufficiently warmed, and condensation may occur. By sufficiently performing the scavenging operation over a predetermined time (3 minutes), the occurrence of condensation in the manifold 120 can be suppressed. Further, since it is not necessary to maintain the temperature of the heat medium after the operation switch is turned off, even if the first heat exchanger 200 or the like is cooled by the scavenging operation (air blowing from the combustion fan 140), the thermal efficiency becomes a problem. It will never be.

  In contrast, when the temperature of the heat medium reaches the fire extinguishing temperature and the burner 110 is extinguished, the temperature of the heat medium is maintained by the intermittent combustion control, and the manifold 120 is sufficiently warmed. Condensation is unlikely to occur in the manifold 120. And in the intermittent combustion control, even if the burner 110 is extinguished, the combustion in the burner 110 is scheduled to be resumed after that. By shortening the scavenging time (10 seconds) shorter than the predetermined time, Cooling of the first heat exchanger 200 and the like due to the scavenging operation (air blowing from the combustion fan 140) can be reduced, and as a result, the thermal efficiency for maintaining the temperature of the heat medium can be improved.

  The heat source device 1 of the present embodiment described above includes the following modifications. In the following, modifications will be described focusing on differences from the above-described embodiment. In the description of the modified example, the same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 5 is a flowchart of the scavenging control process executed by the control unit 150 according to the modification. The scavenging control process of the modified example is also executed when the burner 110 is extinguished by the combustion control process of the burner 110, as in the above-described embodiment. In the scavenging control process of the modified example, when the scavenging operation is started by continuing the blowing of the combustion fan 140 in operation (STEP 200), it is subsequently determined whether or not the outside air temperature is equal to or higher than a reference value (for example, 15 degrees). Judgment is made (STEP 202). The heat source device 1 of the modified example is provided with an outside air temperature sensor (not shown) that detects the outside air temperature. The outside air temperature sensor is connected to the control unit 150.

  If the outside air temperature is equal to or higher than the reference value (15 degrees) (STEP 202: yes), the scavenging time is set to the first predetermined time (STEP 204). In the heat source device 1 of the modified example, if the outside air temperature is equal to or higher than the reference value, it is difficult for condensation to occur in the manifold 120, and the first predetermined time is explosive at the next ignition rather than preventing condensation. It is set to a time sufficient to prevent ignition and post-boiling, for example, 10 seconds.

  On the other hand, when the outside air temperature is lower than the reference value (15 degrees) (STEP 202: no), it is next determined whether or not the burner 110 is extinguished because the temperature of the heating medium has reached the extinguishing temperature. Judgment is made (STEP 206). When the burner 110 is extinguished because the temperature of the heat medium has reached the extinguishing temperature, but the operation switch is turned off (STEP 206: no), the scavenging time is set to be less than the first predetermined time. Is set to a long second predetermined time (STEP 208). If the burner 110 is extinguished before the outside air temperature is lower than the reference value and the manifold 120 is sufficiently warmed, condensation is likely to occur in the manifold 120. Therefore, condensation is prevented as the second predetermined time. For this reason, a sufficient time, for example, 3 minutes is set.

  On the other hand, when the burner 110 is extinguished because the temperature of the heat medium reaches the extinguishing temperature (STEP 206: yes), the scavenging time is extended even if the outside air temperature is lower than the reference value. Instead, the first predetermined time (10 seconds) is set (STEP 204).

  When the scavenging time is set in this manner, it is determined whether or not the scavenging time has elapsed since the burner 110 was extinguished (STEP 210). If the scavenging time has not elapsed (STEP 210: no), the process waits until the scavenging time has elapsed. . Thereafter, when the scavenging time has elapsed (STEP 210: yes), the scavenging operation is terminated by stopping the combustion fan 140 (STEP 212), and the scavenging control process of FIG. 5 is also terminated.

  As described above, in the heat source device 1 of the modified example, it is first determined whether or not the manifold 120 is likely to cause condensation based on the outside air temperature, and the outside air temperature is lower than the reference value (15 degrees) and condensation occurs. In a situation where it is likely to occur, the occurrence of condensation can be suppressed by extending the scavenging time. However, even if the outside air temperature is lower than the reference value, when the temperature of the heat medium reaches the extinguishing temperature and the burner 110 is extinguished, the manifold 120 is sufficiently warmed during the intermittent combustion control, and the manifold 120 Since condensation is unlikely to occur in this case, by not extending the scavenging time, cooling of the first heat exchanger 200 and the like by the scavenging operation (air blowing from the combustion fan 140) is suppressed, and the heat efficiency for maintaining the temperature of the heat medium is improved. be able to.

  As mentioned above, although the heat source device 1 of the present embodiment and the modified example has been described, the present invention is not limited to the above-described embodiment and modified example, and can be implemented in various modes without departing from the gist thereof. It is.

  For example, in the heat source device 1 of the above-described embodiment, heating heat is supplied. However, the heat source device 1 that performs intermittent combustion control is not limited to one that supplies heating heat, It may supply heat for hot water supply. FIG. 6 is an explanatory view showing an example in which heat for supplying hot water is supplied by the heat source device 1. FIG. 6 shows a liquid / liquid heat exchanger 310 provided in the circulation circuit 208 of the heat source device 1. The liquid / liquid heat exchanger 310 has a double pipe structure, and the forward passage 208a and the return passage 208b are connected to the inner pipe 310a so that the heat medium heated by the first heat exchanger 200 circulates. It is like that. On the other hand, the outer pipe 310b has a water supply passage 312 connected to an end portion on the return passage 208b side, and a hot water supply passage 314 connected to an end portion on the outgoing passage 208a side. The water supplied through the water supply passage 312 is heated by heat exchange with the heat medium in the liquid / liquid heat exchanger 310 and then flows into the hot water supply passage 314 as hot water. The water supply passage 312 is provided with a flow sensor (not shown) that detects the flow of water, and this flow sensor is connected to the controller 150. Then, when the flow of water is detected by the flow sensor, the control unit 150 operates the circulation pump 206 and the combustion fan 140 and starts combustion with the burner 110. Also in the heat source device 1 that supplies such hot water supply heat, the present invention can be suitably applied as in the above-described embodiment.

  In the above-described modification, even if the outside air temperature is lower than the reference value (15 degrees), the scavenging time is set to the first predetermined time when the temperature of the heat medium reaches the fire extinguishing temperature and the burner 110 is extinguished. The first predetermined time is set without extending to the second predetermined time (3 minutes) longer than the time (10 seconds). However, the scavenging time in such a case is not limited to the same first predetermined time as when the outside air temperature is equal to or higher than the reference value, and if shorter than the second predetermined time, it is longer than the first predetermined time (for example, 30). Second). Even if it does in this way, compared with the case where scavenging time is set to the 2nd predetermined time, since cooling of the 1st heat exchanger 200 etc. by scavenging operation (blast of combustion fan 140) is controlled, it is in intermittent combustion control. It is possible to improve the thermal efficiency for maintaining the temperature of the heat medium. Of course, the heat efficiency can be improved as the scavenging time is set shorter.

DESCRIPTION OF SYMBOLS 1 ... Heat source apparatus, 100 ... Combustion unit, 102 ... Combustion chamber,
110 ... Burner, 112 ... Flame port, 114 ... Gas inlet,
116: mixing passage, 120 ... manifold, 122 ... nozzle,
124 ... gas flow hole, 126 ... distribution passage, 130 ... gas flow path,
132 ... Main valve, 134 ... Proportional valve, 136a ... First switching valve,
136b ... second switching valve, 140 ... combustion fan, 142 ... spark plug,
150 ... control unit, 200 ... first heat exchanger, 202 ... second heat exchanger,
204 ... Communication passage, 206 ... Circulation pump, 208 ... Circulation circuit,
208a ... outward passage, 208b ... return passage, 210 ... heat medium temperature sensor,
222 ... drain pipe, 224 ... neutralizer, 230 ... exhaust port,
300 ... Heating terminal, 310 ... Liquid / liquid heat exchanger, 310a ... Inner tube,
310b ... Outer pipe, 312 ... Water supply passage, 314 ... Hot water supply passage.

Claims (2)

A burner for burning the fuel gas injected from the nozzle;
A combustion fan for sending combustion air toward the burner;
A heat exchanger that heats the heat medium by heat exchange with the combustion exhaust from the burner;
A combustion control unit that controls the amount of the fuel gas supplied to the burner to adjust the temperature of the heating medium;
An exhaust port for discharging the combustion exhaust gas that has passed through the heat exchanger to the outside;
A scavenging control unit for controlling the execution of a scavenging operation for discharging the combustion exhaust gas from the exhaust port by maintaining the ventilation of the combustion fan for a predetermined time after extinguishing the burner, and through the heat medium In the heat source device that supplies heat,
When the temperature of the heating medium exceeds a predetermined temperature, the combustion control unit can perform intermittent combustion control that repeats extinguishing and burning of the burner so as to maintain the temperature of the heating medium.
The scavenging control unit makes the execution time of the scavenging operation shorter than the predetermined time when the burner is extinguished by the intermittent combustion control. The heat source device according to claim 1,
It has an outside air temperature sensor that detects outside air temperature,
The scavenging control unit
When the detected temperature of the outside air temperature sensor is equal to or higher than a reference value, the scavenging operation is executed over a first predetermined time,
When the detected temperature of the outside air temperature sensor is lower than the reference value, the scavenging operation is performed over a second predetermined time longer than the first predetermined time,
When the burner is extinguished by the intermittent combustion control, even if the detected temperature of the outside air temperature sensor is lower than the reference value, the execution time of the scavenging time is shorter than the second predetermined time. The heat source device is set to be equal to or longer than the first predetermined time.

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