JP5209365B2 - Water heater - Google Patents

Description

  The present invention relates to a water heater for obtaining hot water by heat exchange with combustion exhaust gas.

  Conventionally, a water heater for obtaining hot water by heat exchange with combustion exhaust gas has been used (see, for example, Patent Document 1). The water heater includes a combustion burner disposed in the combustion chamber, a heat exchanger and a drain pan disposed above the combustion burner, a water supply passage connected to the inflow side of the heat exchanger, and a heat exchanger. A hot water flow path connected to the outflow side of the. The heat exchanger has a main heat exchanger section disposed on the lower side of the drain pan and a sub heat exchanger section disposed on the upper side of the drain pan. The drain pan is provided with a drain channel, and a neutralizer, a drain tank, and a drain pump are provided in the drain channel. A neutralizer such as calcium carbonate is accommodated in the neutralizer. The drain tank is provided with an upper limit water level detection sensor for detecting the upper limit water level of the condensed water in the drain tank and a lower limit water level detection sensor for detecting the lower limit water level of the condensed water in the drain tank.

  The hot water supply operation by this water heater is performed as follows. The water to be heated is supplied to the auxiliary heat exchanger part of the heat exchanger through the water supply flow path, and flows through the auxiliary heat exchanger part and the main heat exchanger part. Further, the combustion exhaust gas from the combustion burner flows upward in the combustion chamber and is discharged to the outside. Hot water is generated by heat exchange between the water flowing through the sub heat exchanger section and the main heat exchanger section and the combustion exhaust gas, and the generated hot water is discharged from the main heat exchanger section through the hot water flow passage. When heat exchange is performed in this way, the combustion exhaust gas is supercooled in the sub heat exchanger section, the water vapor in the combustion exhaust gas is condensed, and condensed water adheres to the surface of the sub heat exchanger section. This condensed water is collected by dripping into the drain pan, and the collected condensed water is fed to the neutralizer through the drain passage, neutralized by the neutralizing agent in the neutralizer, and then into the drain tank. Stored.

  The condensed water stored in the drain tank is discharged as follows. When the water level of the condensed water in the drain tank rises above the upper limit water level, the drain pump is activated based on the detection signal from the upper limit water level detection sensor, and the drain operation is performed. In this drainage operation, the condensed water in the drain tank is discharged to the outside through the drain channel by the action of the drainage pump. Thereafter, when the level of the condensed water in the drain tank falls below the lower limit water level, the operation of the discharge pump is stopped based on the detection signal from the lower limit detection sensor, and the drainage operation is terminated.

JP 2002-130830 A

  However, in the above-described conventional water heater, condensed water may remain in the drain channel after the drainage operation is completed. The condensed water neutralized by the neutralizer contains a calcium component. Therefore, when the condensed water remains in the drain channel, the calcium component in the condensed water is deposited in the drain channel. Thus, when precipitation of a calcium component is repeated for a long time, there exists a problem that there exists a possibility that a drain flow path may be obstruct | occluded by the precipitated calcium component.

  The objective of this invention is providing the water heater which can prevent that condensed water remains in a drain flow path.

In the water heater according to claim 1 of the present invention , the combustion burner, the heat exchanger for heating water using the heat of the combustion exhaust gas from the combustion burner, and the heat exchanger should be heated. A water supply channel for supplying water, and a hot water flow channel for discharging hot water heated by the heat exchanger,
The heat exchanger has a main heat exchanger portion disposed on the upstream side in the flow direction of the combustion exhaust gas, and a sub heat exchanger portion disposed on the downstream side in the flow direction of the combustion exhaust gas, A drain pan for collecting condensed water generated in the auxiliary heat exchanger section in relation to the auxiliary heat exchanger section, and a neutralizer for neutralizing the condensed water collected by the drain pan. A drain tank for storing the condensed water neutralized by the neutralizer, a drain channel for discharging the condensed water stored in the drain tank, and a drain disposed in the drain channel. A pump,
The drain tank is provided with a water level detection means for detecting the water level of the condensed water stored in the drain tank, and the water level detection means includes an upper limit water level detection sensor and a condensed water for detecting an upper limit water level of the condensed water. Including a lower limit water level detection sensor for detecting the lower limit water level of
Furthermore, timer means is provided for measuring an operation interval time until the drainage operation is performed again after the drainage operation for draining the condensed water stored in the drain tank is performed,
When the upper limit water level of the condensed water is detected by the upper limit water level detection sensor, the drainage pump is actuated to perform the drainage operation, and then the lower limit water level detection sensor detects the lower limit water level of the condensed water. When the pump is stopped and the drainage operation is completed, and the timer means counts a predetermined time interval or more after the drainage operation is performed and the drainage operation is performed again, the drainage operation is terminated. After that, the drain pump is operated to perform a purge operation for draining the condensed water remaining in the drain flow path. The purge operation is performed after the lower limit water level of the condensed water is detected by the lower limit water level detection sensor. It is characterized by ending when time elapses.

Further, in the water heater according to claim 2 of the present invention, an operation time setting means for setting an operation time of the drainage pump in the purge operation is further provided in relation to the drainage pump, and the operation time The setting means sets an operation time of the drainage pump based on an operation time of the drainage operation of the drainage pump.

Furthermore, in the water heater according to claim 3 of the present invention, in the drain operation, the drain pump is operated at a first predetermined rotation speed, and in the purge operation, the drain pump is operated at the first predetermined rotation speed. It is characterized by being operated at a second predetermined rotational speed greater than that.

According to the water heater according to claim 1 of the present invention, the water level detecting means disposed in the drain tank, the lower limit water level for detecting the lower limit level of the upper water level sensor and the condensed water for detecting the upper limit water level of the condensed water When the upper limit water level of the condensate is detected by the upper limit water level detection sensor, the drainage pump is activated and the drainage operation is performed, and then the lower limit water level detection sensor detects the lower limit water level of the condensate. Since the pump is stopped and the drainage operation is completed, the condensed water stored in the drain tank can be drained through the drain passage. In addition, timer means for measuring the operation interval time until the drainage operation is performed again after the drainage operation for draining the condensed water is provided, and the drainage operation is performed again after the timer means performs the drainage operation. If the operation interval until a predetermined time interval is counted, the drain pump is activated and the purge operation for draining the condensed water remaining in the drain channel is performed after the drain operation is completed. The remaining condensed water can be discharged to the outside through the drain channel.

Moreover, according to the hot water heater according to claim 2 of the present invention, the amount of condensed water remaining in the drain passage tends to be proportional to the operation time of the drainage operation, and is therefore based on the operation time of the drainage operation. By setting the operation time of the drainage pump in the purge operation, the operation time of the drainage pump can be set according to the time required to discharge the condensed water remaining in the drainage channel. Residual condensed water can be discharged reliably.

Furthermore, according to the water heater of claim 3 of the present invention, the air fed into the drain flow path by the drain pump by making the rotational speed of the drain pump in the purge operation larger than the rotational speed of the drain pump in the drain operation. The condensed water remaining in the drain channel can be discharged more reliably.

  Hereinafter, an embodiment of a water heater according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a water heater according to an embodiment of the present invention, FIG. 2 is a block diagram showing a control system of the water heater of FIG. 1, and FIG. 3 is a purge by the water heater of FIG. It is a flowchart which shows the flow of a driving | operation.

  Referring to FIG. 1, the illustrated hot water heater 2 includes a hot water supply housing 4. A combustion chamber 6 is formed inside the hot water supply housing 4, and an exhaust passage 8 is formed at the upper end of the combustion chamber 6. Has been. Further, in the hot water supply housing 4, for example, a first hot water supply means 10 for supplying hot water to a hot water device (not shown) such as a bathroom currant or a bathtub, and a hot water heater (for example, a floor heating device) ( (Not shown) is provided with second hot water supply means 12 for supplying hot water.

  The first hot water supply means 10 includes a first combustion burner 14 disposed in the combustion chamber 6, a first heat exchanger 16 and a first drain pan 18 provided above the first combustion burner 14, and a first heat exchange. The water supply flow path 20 connected to the inflow side of the heat exchanger 16 and the hot water flow path 22 connected to the outflow side of the first heat exchanger 16 are provided. The first combustion burner 14 is supplied with a fuel gas from a gas supply source (not shown), and the first combustion burner 14 burns the fuel gas to generate combustion exhaust gas.

  The first heat exchanger 16 includes a first main heat exchanger portion 24 disposed below the first drain pan 18, and a first sub heat exchanger portion 26 disposed above the first drain pan 18. ,have. A water supply flow path 20 is connected to the first sub heat exchanger section 26, and a hot water flow path 22 is connected to the first main heat exchanger section 24. A bypass flow path 28 is connected between the feed water flow path 20 and the hot water flow path 22, and a mixing valve 29 is disposed at a connection portion between the hot water flow path 22 and the bypass flow path 28. Further, a hot water supply flow path 30 branches and extends from the hot water supply flow path 22, and an open / close valve 32 is disposed in the hot water supply flow path 30. The upstream end of the water supply channel 20 is connected to a water supply source (not shown), and the downstream end of the tap water flow channel 22 is connected to a bathroom curan (not shown).

  Further, a reheating flow path 34 and a reheating return flow path 36 are connected to the hot water supply flow path 30, and a reheating heat exchanger 38 is disposed in the reheating flow path 34. A circulation pump 40 is disposed in the path 36. The downstream end of the follow-up flow channel 34 and the upstream end of the follow-up return channel 36 are each connected to a hot water supply port (not shown) provided in the bathtub of the bathroom.

  The second hot water supply means 12 includes a second combustion burner 42 disposed in the combustion chamber 6, a second heat exchanger 44 and a second drain pan 46 provided above the second combustion burner 42, and a second heat exchange. A hot water return flow path 48 connected to the inflow side of the vessel 44 and a hot water return flow path 50 connected to the outflow side of the second heat exchanger 44. The second combustion burner 42 is supplied with fuel gas from a gas supply source (not shown), and the fuel gas is burned in the second combustion burner 42 to generate combustion exhaust gas. The second heat exchanger 44 includes a second main heat exchanger portion 52 disposed on the lower side of the second drain pan 46, and a second sub heat exchanger portion 54 disposed on the upper side of the second drain pan 46. ,have. A warm water return channel 48 is connected to the second auxiliary heat exchanger unit 54, and a warm water going channel 50 is connected to the second main heat exchanger unit 52, and the downstream end of the warm water going channel 50 is connected. And the upstream edge part of the warm water return flow path 48 is each connected to the floor heating apparatus (not shown). A circulation pump 56 is disposed between the second sub heat exchanger section 54 and the second main heat exchanger section 52. Further, a bypass flow path 58 that bypasses the warm water flow path 50 is connected to the warm water flow path 50, and the bypass flow path 58 is disposed inside the reheating heat exchanger 38.

  Each of the first and second drain pans 18 and 46 is inclined downward toward one end thereof, and one end of each of the first and second drain pans 18 and 46 has an upstream end of the drain channel 60. Is connected. A neutralizer 62 is disposed on the upstream side of the drain passage 60, and a drain tank 64 and a drain pump 66 are disposed on the downstream side thereof. The neutralizer 62 includes a main body housing 68 in which a neutralizing agent (not shown) such as calcium carbonate is accommodated. An upper limit water level detection sensor 70 (which constitutes a water level detection means) for detecting the upper limit water level of the condensed water in the drain tank 64 is provided at the upper end portion in the drain tank 64, and the lower end portion in the drain tank 64 Is provided with a lower limit water level detection sensor 72 (which constitutes a water level detection means) for detecting the lower limit water level of the condensed water in the drain tank 64. The downstream side of the drain channel 60 extends from the drain tank 64 and is disposed as required, for example, in the underfloor space of the bathroom, and its downstream end is a drain port (not shown) provided in the bathtub of the bathroom. )It is connected to the.

  In the water heater 2 of the present embodiment, a control means 74 for controlling the operation of the drain pump 66 is provided (see FIG. 2). The control means 74 includes a count means 76, a timer means 78, a memory 80, an operation time setting means 82, and an operation control means 84. The counting means 76 counts the number of times a drainage operation described later is performed. The timer unit 78 detects the lower limit water level of the condensed water by the lower limit water level detection sensor 72 after the upper limit water level of the condensed water is detected by the upper limit water level detection sensor 70 after the operation time of the drainage operation by the drain pump 66. Measure the time to complete. The memory 80 includes count value data (for example, 10 times) regarding the count value of the counting means 76, first predetermined rotation speed data (for example, 3000 rpm) regarding the rotation speed of the drain pump 66 in the drain operation, and the drain pump 66 in the purge operation. Second predetermined rotation speed data (for example, 3500 rpm) relating to the rotation speed is stored. The operation time setting means 82 sets the operation time of the drainage pump 66 in the purge operation based on the measurement time of the timer means 78 (that is, the operation time of the last drainage operation), and in this embodiment, the drainage in the purge operation. The operation time of the pump 66 is set to the same time as the operation time of the drainage operation. The operation control unit 84 controls the operation of the drainage pump 66 based on the count value of the counting unit 76 and the detection signals from the upper limit water level detection sensor 70 and the lower limit water level detection sensor 72 as described later.

  The hot water supply operation by the hot water heater 2 described above will be described as follows. When hot water is supplied to the hot water device, the first hot water supply means 10 is operated, the first combustion burner 14 is operated, and the on-off valve 32 is kept closed. Water to be heated from the water supply source is supplied to the first sub heat exchanger section 26 of the first heat exchanger 16 through the water supply flow path 20, and the first sub heat exchanger section 26 and the first main heat exchanger section. Flows through 24. The combustion exhaust gas from the first combustion burner 14 flows upward in the combustion chamber 6 and is discharged to the outside through the exhaust passage 8. Hot water is generated by heat exchange between the water flowing through the first sub heat exchanger section 26 and the first main heat exchanger section 24 and the combustion exhaust gas, and the generated hot water flows through the hot water flow path 22. The mixing valve 29 appropriately mixes the hot water flowing through the hot water flow path 22 and the water flowing from the water supply flow path 20 into the hot water flow path 22 through the bypass flow path 28 and adjusts the temperature. It is supplied to the bathroom currant through the flow path 22.

  Further, when hot water is stored in the bathtub in the bathroom, the first hot water supply means 10 is operated, the first combustion burner 14 is operated, and the on-off valve 32 is held open. As described above, hot water is generated by the first heat exchanger 16, and the temperature of a part of the hot water flowing through the hot water flow path 22 is adjusted and then flows into the hot water flow path 30. It is supplied to the hot water outlet of the bathtub.

  Moreover, when supplying warm water to a floor heating apparatus, the 2nd hot water supply means 12 is operated, and the 2nd combustion burner 42 and the circulation pump 56 are each operated. By the action of the circulation pump 56, the water to be heated from the floor heating device is supplied to the second sub heat exchanger section 54 of the second heat exchanger 44 through the hot water return channel 48, and the second sub heat exchanger section. 54 and the second main heat exchanger section 52. Further, the combustion exhaust gas from the second combustion burner 42 flows upward in the combustion chamber 6 and is discharged to the outside through the exhaust passage 8. Hot water is generated by heat exchange between the water flowing through the second sub heat exchanger section 54 and the second main heat exchanger section 52 and the combustion exhaust gas, and the generated hot water is passed to the floor heating device through the warm water flow path 50. Supplied.

  Further, when the hot water in the bathtub is replenished, the second hot water supply means 12 is operated, the second combustion burner 42 and the circulation pumps 40 and 56 are respectively operated, and the on-off valve 32 is kept closed. . By the action of the circulation pump 40, the hot water to be heated in the bathtub is circulated through the follow-up return channel 36, the follow-up heat exchanger 38 and the follow-up flow channel 34. In the same manner as described above, warm water is generated by the second heat exchanger 44, and a part of the warm water flowing through the warm water going flow path 50 flows through the bypass flow path 58, and warm water flowing through the bypass flow path 58 in the reheating heat exchanger 38. And the hot water flowing through the follow-up flow path 34 are exchanged. By this heat exchange, the hot water flowing through the follow-up flow path 34 is heated, and the heated hot water is supplied to the hot water outlet of the bathtub.

  Next, the purge operation by the water heater 2 described above will be described. When the hot water supply operation of the water heater 2 is started, the water flowing through the first and / or second auxiliary heat exchanger units 26 and 54 absorbs the latent heat of the combustion exhaust gas, and the first and / or second main heat. The water flowing through the exchanger parts 24 and 52 absorbs the sensible heat of the combustion exhaust gas. Thereby, the temperature of the combustion exhaust gas heat-exchanged in the 1st and / or 2nd main heat exchanger part 24,52 is about 200 degreeC, for example, and the 1st and / or 2nd sub heat exchanger part 26,54 is. The temperature of the combustion exhaust gas heat-exchanged at is about 70 ° C., for example, so that the combustion exhaust gas in the combustion exhaust gas at the upper part of the combustion chamber 6 where the first and / or second sub-heat exchanger sections 26 and 54 are arranged The water vapor is condensed, and condensed water adheres to the surfaces of the first and / or second auxiliary heat exchanger units 26 and 54. The condensed water is collected by being dropped onto the first and / or second drain pans 18, 46, and the collected condensed water flows into the main body housing 68 of the neutralizer 62 through the drain channel 60. And neutralized with a neutralizing agent and then stored in the drain tank 64.

  When the condensed water is stored in the drain tank 64 as described above, a detection state is detected in which the water level of the condensed water in the drain tank 64 is detected (step S1). When the water level of the condensed water in the drain tank 64 rises above the upper limit water level, the drainage operation is started (steps S2 and S3), and measurement of the timer means 78 is started based on the detection signal from the upper limit water level detection sensor 70. Then (step S4), the operation control means 84 operates the drain pump 66 at a first predetermined rotation speed (eg, 3000 rpm) (step S5). The counting means 76 counts up the number of times of drainage operation (step S6). In this drainage operation, the condensed water in the drain tank 64 is discharged through the drain passage 60 by the action of the drain pump 66, and the discharged condensed water is fed to the drain outlet of the bathtub through the drain passage 60.

  When the water level of the condensed water in the drain tank 64 is lowered below the lower limit water level by performing the drainage operation in this way (step S7), the timer means 78 is based on the detection signal from the lower limit water level detection sensor 72. Is finished (step S8). At this time, when the count value of the count means 76 has not reached the count value stored in the memory, that is, 10 times in this embodiment, the process proceeds from step S9 to step S10, and the operation control means 84 operates the drain pump 66. The drainage operation is terminated (step S11). When the drainage operation is completed, the process proceeds from step S11 to step S2.

  In step S9, when the count value of the counting means 76 reaches 10 times, the process proceeds from step S9 to step S12, the operation control means 84 continues the operation of the drain pump 66, the drain operation is terminated and the purge operation is performed. Start (step S13). When the purge operation is started, the operation time setting unit 82 sets the operation time of the drain pump 66 in the purge operation based on the measurement time of the timer unit 78 in the immediately preceding drain operation (step S14). In this embodiment, when the measurement time of the timer means 78 is, for example, 2 minutes, the operation time of the drain pump 66 in the purge operation is set to 2 minutes. In this purge operation, the operation control means 84 increases the rotation speed of the drain pump 66 and operates the drain pump 66 at a second predetermined rotation speed (for example, 3500 rpm) larger than the first predetermined rotation speed for 2 minutes. As a result, the compressed air from the drain pump 66 is sent to the drain channel 60, and the condensed water remaining in the drain channel 60 is fed to the drain outlet of the bathtub through the drain channel 60 by the action of the compressed air.

  When the operation time of the drain pump has passed 2 minutes (step S15), the operation control means 84 stops the operation of the drain pump 66 (step S16), and the purge operation is ended (step S17). When the purge operation is finished, the count value of the counting means 76 is reset (step S18).

  Therefore, in the water heater 2 of the present embodiment, since the purge operation is performed after the drainage operation is completed, it is possible to prevent the condensed water after neutralization from remaining in the drain passage 60. Thereby, it is suppressed that the calcium component contained in the condensed water after neutralization precipitates in the drain channel 60, and it is possible to prevent the drain channel 60 from being blocked by the precipitated calcium component.

  In this embodiment, the operation time setting means 82 sets the operation time of the drainage pump 66 in the purge operation to the same time as the operation time of the immediately preceding drainage operation, but a predetermined time than the operation time of the immediately preceding drainage operation. It may be set to a longer (or shorter) time (for example, 5 minutes).

  Next, with reference to FIG.4 and FIG.5, other embodiment of the water heater according to this invention is described. FIG. 4 is a block diagram showing a control system of a water heater according to another embodiment of the present invention, and FIG. 5 is a flowchart showing a flow of a purge operation by the water heater of FIG. In other embodiments, components that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 4, in water heater 2A according to another embodiment, control means 74A includes timer means 86, memory 80A, and operation control means 84A. The timer means 86 measures the operation interval time until the drainage operation is performed again after the drainage operation is performed. In the memory 80A, in addition to the first and second predetermined rotation speed data, the operation time data (for example, 1 minute) related to the operation time of the drain pump 66 in the purge operation, and the drain operation is performed again after the drain operation is performed. The operation interval time data (for example, 72 hours) related to the operation interval time until it is displayed is stored. The operation control unit 84A controls the operation of the drainage pump 66 as described later based on the measurement time of the timer unit 86 and the detection signals from the upper limit water level detection sensor 70 and the lower limit water level detection sensor 72.

  Next, with reference also to FIG. 5, the drainage operation and the purge operation by the hot water heater 2A described above will be described. As described above, when condensed water is stored in a drain tank (not shown), a detection state is detected in which the level of condensed water in the drain tank is detected (step S31). When the condensate water level in the drain tank rises above the upper limit water level, the drainage operation is started (steps S32 and S33). Based on the detection signal from the upper limit water level detection sensor 70, the operation control means 84A operates the drainage pump 66. Is operated (step S34). Thereafter, when the water level of the condensed water in the drain tank is lowered below the lower limit water level (step S35), the operation control means 84A stops the operation of the drainage pump 66 based on the detection signal from the lower limit water level detection sensor 72. (Step S36), the drainage operation is terminated (Step S37). When the drainage operation is completed, measurement by the timer means 86 is started (step S38), and thereafter, steps S39 to S41 are performed in the same manner as steps S32 to S34 described above, and the drainage operation is performed again.

  When the drainage operation is performed again in this manner, the measurement of the timer means 86 is terminated (step S42). After that, when the water level of the condensed water in the drain tank is lowered below the lower limit water level, the process proceeds from step S43 to step S44. move on. When the measured time of the timer means 86 is less than the operation interval time stored in the memory 80A, or 72 hours or less in this embodiment, the process proceeds from step S44 to step S45, and the operation control means 84A stops the operation of the drain pump 66. The drainage operation is terminated (step S46). When the drainage operation is completed, the process proceeds from step S46 to step S38.

  In step S44, when the time measured by the timer means 86 is 72 hours or more, the process proceeds from step S44 to step S47, where the drain operation is terminated and the purge operation is started (step S48). When the purge operation is started, the operation control unit 84A operates the drain pump 66 for the operation time stored in the memory 80A, in this embodiment, for one minute. When the operation time of the drain pump 66 has passed 1 minute (step S49), the operation control means 84A stops the operation of the drain pump 66 (step S50), and the purge operation is ended (step S51).

  In this embodiment, the operation time data stored in the memory 80A is set to 1 minute, but this operation time data is stored in the drain flow path (not shown) from the drain tank to the bathtub outlet (not shown). )) Can be set as appropriate according to the length and arrangement state. For example, when the length of the drain channel is about 25 m, the operation time data is set to 1 minute, and when the length of the drain channel is about 10 m, the operation time data is set to 30 seconds. By setting in this way, the condensed water remaining in the drain channel can be discharged more effectively.

  In this embodiment, the purge operation is performed when the measurement time of the timer means 86 is 72 hours or more. However, the control means 74A is further provided with the counting means 76 of the above embodiment, and the timer means 86 is provided. The purge operation may be performed when the measurement time is 72 hours or more or when the count value of the counting means 76 reaches 10 times.

  As mentioned above, although embodiment of the various water heaters according to this invention was described, this invention is not limited to this embodiment, A various deformation | transformation thru | or correction | amendment are possible without deviating from the scope of this invention.

It is the schematic which shows the water heater by one Embodiment of this invention. It is a block diagram which shows the control system of the water heater of FIG. It is a flowchart which shows the flow of the purge driving | operation by the water heater of FIG. It is a block diagram which shows the control system of the water heater by other embodiment of this invention. It is a flowchart which shows the flow of the purge driving | operation by the water heater of FIG.

Explanation of symbols

2,2A Water heater 14 First combustion burner 16 First heat exchanger 18 First drain pan 20 Water supply flow path 22 Hot water discharge flow path 24 First main heat exchanger section 26 First sub heat exchanger section 42 Second combustion burner 44 Second heat exchanger 46 Second drain pan 52 Second main heat exchanger section 54 Second auxiliary heat exchanger section 62 Neutralizer 64 Drain tank 66 Drain pump 70 Upper limit water level detection sensor 72 Lower limit water level detection sensor

Claims (3)

A combustion burner, a heat exchanger for heating water using the heat of combustion exhaust gas from the combustion burner, a water supply passage for supplying water to be heated to the heat exchanger, and the heat A tapping channel for tapping water heated by the exchanger,
The heat exchanger has a main heat exchanger portion disposed on the upstream side in the flow direction of the combustion exhaust gas, and a sub heat exchanger portion disposed on the downstream side in the flow direction of the combustion exhaust gas, A drain pan for collecting condensed water generated in the auxiliary heat exchanger section in relation to the auxiliary heat exchanger section, and a neutralizer for neutralizing the condensed water collected by the drain pan. A drain tank for storing the condensed water neutralized by the neutralizer, a drain channel for discharging the condensed water stored in the drain tank, and a drain disposed in the drain channel. A pump,
The drain tank is provided with a water level detection means for detecting the water level of the condensed water stored in the drain tank, and the water level detection means includes an upper limit water level detection sensor and a condensed water for detecting an upper limit water level of the condensed water. Including a lower limit water level detection sensor for detecting the lower limit water level of
Furthermore, timer means is provided for measuring an operation interval time until the drainage operation is performed again after the drainage operation for draining the condensed water stored in the drain tank is performed,
When the upper limit water level of the condensed water is detected by the upper limit water level detection sensor, the drainage pump is actuated to perform the drainage operation, and then the lower limit water level detection sensor detects the lower limit water level of the condensed water. When the pump is stopped and the drainage operation is completed, and the timer means counts a predetermined time interval or more after the drainage operation is performed and the drainage operation is performed again, the drainage operation is terminated. After that, the drain pump is operated to perform a purge operation for draining the condensed water remaining in the drain flow path. The purge operation is performed after the lower limit water level of the condensed water is detected by the lower limit water level detection sensor. A water heater that ends when time passes. In relation to the drainage pump, an operation time setting means for setting an operation time of the drainage pump in the purge operation is further provided, and the operation time setting means is set to an operation time of the drainage operation of the drainage pump. based on, water heater according to claim 1, characterized in that setting the operating time of the drain pump. In the drain operation, the drain pump is operated at a first predetermined rotational speed, and in the purge operation, the drain pump is operated at a second predetermined rotational speed that is greater than the first predetermined rotational speed. The water heater according to claim 1 .

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