Heating device

Abstract

To provide a heating device capable of quickly and accurately detecting circulation failure of hot water in a circulation passage.SOLUTION: A water heater 11 includes a pump for circulating hot water generated by a heat exchanger in a circulation passage composed of a feed passage and a return passage, a temperature sensor for detecting the temperature of the feed passage near the heat exchanger, and a control part 111. The control unit 111 includes a first determination mode 111a for adding 1 to the count value and stopping the heating operation based on the degree of increase in the detected temperature near immediately after the start of the heating operation being less than a first threshold, a second determination mode 111b for adding 1 to the count value and stopping the heating operation based on the degree of increase in the detected temperature during the heating operation being equal to or greater than a second threshold, and a third determination mode 111c for adding 1 to the count value based on the degree of increase in the detected temperature being equal to or greater than a third threshold after the heating operation is stopped.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heating device that generates hot and cold water using heat from a heater. [Background technology]

[0002] Conventionally, heating devices that generate hot water using heat from a heater have been used for hot water supply, floor heating, room heating, bathroom heating, etc. In these functions, each heating function is realized by circulating hot water between the heating device and the corresponding heating terminal. However, when the heating function is performed, hot water may not circulate properly due to some factors (freezing of the circulation path, foreign matter trapped, air trapped, etc.). For example, a gas burner is used as the heater, and hot water is generated by the heat of combustion.

[0003] The following Patent Document 1 describes a hot water heating device that can detect poor circulation in a hot water circulation path. This hot water heating device includes a circulation path consisting of a feed pipe and a return pipe for connecting a hot water storage tank and a radiator, a pump located in the feed pipe for circulating hot water, a heat exchanger for heating the hot water, and a temperature sensor located in the return pipe for detecting the temperature of the circulating hot water. The hot water heating device heats the heat exchanger while operating the pump, and determines that poor circulation has occurred if the rate of increase in temperature detected by the temperature sensor over a certain period of time is not equal to or greater than a predetermined constant temperature increase rate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-117646 Summary of the Invention [Problem to be solved by the invention]

[0005] If the combustion operation (heating operation) continues without proper circulation of hot water, the inside of the boiler body, including the heat source, may become excessively hot, which may damage the boiler body. Therefore, it is preferable to detect poor circulation of hot water as early as possible after combustion has started and promptly stop the combustion operation. In the method of Patent Document 1, after the combustion operation has started, it is necessary to wait until the detection of poor circulation until hot water circulates in the return pipe and the above-mentioned judgment can be made. For this reason, it is difficult to promptly stop the combustion operation when circulation is poor.

[0006] In view of the above problem, an object of the present invention is to provide a heating device that can quickly and accurately detect poor circulation of hot and cold water in a circulation path. [Means for solving the problem]

[0007] A heating device according to a main aspect of the present invention comprises a heat exchanger that generates hot water by heating using a heating unit, a pump that circulates the hot water generated by the heat exchanger through a circulation path consisting of a feed path and a return path, a temperature sensor that detects the temperature of the feed path near the heat exchanger, and a control unit that determines poor circulation of the hot water in the circulation path based on the temperature detected by the temperature sensor while the pump is operating. The control unit has a first determination mode in which, based on the degree of increase in the detected temperature immediately after the start of the heating operation of the heating unit, 1 is added to the count value and the heating operation is stopped based on the degree of increase in the detected temperature being less than a first threshold; a second determination mode in which, based on the degree of increase in the detected temperature being equal to or greater than a second threshold during the heating operation of the heating unit, 1 is added to the count value and the heating operation is stopped based on the degree of increase in the detected temperature being equal to or greater than a third threshold after the heating operation of the heating unit has stopped; and a third determination mode in which, when the heating operation is stopped in the first determination mode or the second determination mode, the heating operation is resumed if the count value is not equal to or greater than a predetermined threshold, and it is determined that poor circulation has occurred if the count value becomes equal to or greater than the threshold.

[0008] According to the heating device of this aspect, the first, second, and third determination modes are executed in parallel, and if an increment occurs in the count value in the first or second determination mode, the heating operation is stopped and then restarted, and processing for each determination mode is performed. Therefore, as described in detail in the following embodiments, the total time of the heating operation until the count value reaches or exceeds a threshold and poor circulation is detected can be effectively reduced, and poor circulation can be accurately detected. [Effects of the Invention]

[0009] As described above, according to the present invention, a heating device can be provided that can quickly and accurately determine poor circulation in the hot and cold water circulation path.

[0010] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the embodiments shown below are merely examples of how the present invention can be implemented, and the present invention is not limited to the embodiments described below. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a configuration of a water heater according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a circuit block of the water heater according to the embodiment. [Figure 3] FIG. 3 is a diagram schematically showing the configuration of a combustion system and piping of a water heater according to an embodiment. [Figure 4] FIG. 4 is a graph showing the change in temperature detected by a thermistor placed in the circulation pipe near the heat exchanger when the second supply unit is operated to perform the room heating function or the bathroom heating function. [Figure 5] 5A and 5B are flowcharts showing the process of the control unit in a first determination mode and a second determination mode, respectively, according to an embodiment; [Figure 6]FIG. 6 is a flowchart showing the processing of the control unit in the third determination mode according to the embodiment. [Figure 7] FIG. 7 is a flowchart showing a process for determining whether or not there is a poor circulation of hot and cold water in the circulation path according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] In the following embodiment, a hot water supply device 1 is exemplified that can perform bath functions such as an automatic bath function, a reheating function, a hot water addition function, and a cold water addition function, as well as a heating function using hot water.

[0014] FIG. 1 is a diagram showing a configuration of a water heater 1 according to an embodiment.

[0015] The water heater 1 includes a water heater 11 and remote controllers 12 and 13. The water heater 11 is a gas water heater that uses gas as fuel to supply hot water. The water heater 11 is a heating device that generates hot water using combustion heat. The hot water generated by the water heater 11 is supplied to a kitchen faucet, bathtub, faucet, etc. via piping connected to the corresponding hot water outlet 11a. The water heater 11 also circulates the hot water to heating terminals that provide floor heating, bathroom heating, and room heating functions via piping connected to the corresponding hot water outlet 11a.

[0016] Remote controllers 12 and 13 are connected to water heater 11 and are used to make various settings for each function of water heater 1. Remote controller 12 has display unit 121 and input unit 122, and remote controller 13 has display / input unit 131 consisting of a touch panel and operation button 132. The operator can make any settings for hot water filling, hot water supply temperature, hot water filling temperature, etc. by operating input unit 122 according to the screen displayed on display unit 121. The operator can also make settings for hot water filling, hot water filling temperature, etc. by operating display / input unit 131.

[0017] The remote controller 12 is installed in a bathroom, and the remote controller 13 is installed in a kitchen, etc. The remote controllers 12 and 13 are provided with audio windows 12a and 13a for inputting and outputting audio.

[0018] Hereinafter, the remote controller 12 installed in the bathroom will be referred to as the "bathroom remote control 12," and the remote controller 13 installed in the kitchen or the like will be referred to as the "kitchen remote control 13."

[0019] Input section 122 of bathroom remote control 12 includes operation button 122a. Operation buttons 122a and 132 are buttons for switching water heater 11 between an operation on state and an operation off state.

[0020] Furthermore, input unit 122 and display input unit 131 include buttons for changing the hot water supply temperature and the hot water filling temperature. By operating these buttons, the operator can change the set temperatures for hot water supply and hot water filling. In addition, input unit 122 and display input unit 131 include buttons for controlling the operation of water heater 11, such as buttons for executing the automatic bath function, reheating function, hot water addition function, water addition function, etc., and a button for setting the time from when the automatic bath function is turned on until it is automatically turned off.

[0021] In addition to bathroom remote control 12 and kitchen remote control 13, water heater 1 also includes a heating remote control (not shown) for turning on / off various heating operations and setting various heating-related functions. The heating remote control is installed near the location where the heating device is installed, such as at the entrance to the living room or bathroom.

[0022] FIG. 2 is a block diagram showing the configuration of the circuit section of the water heater 11.

[0023] The water heater 11 includes a control unit 111 , a storage unit 112 , a communication unit 113 , a detection unit 114 , a drive unit 115 , a display unit 116 , and a sound output unit 117 .

[0024] Control unit 111 includes a microcomputer and controls each unit in water heater 11 in accordance with a program stored in storage unit 112. Storage unit 112 includes a memory and stores a predetermined control program. Control unit 111 executes the control program stored in storage unit 112, thereby achieving the functions of first determination mode 111a, second determination mode 111b, and third determination mode 111c. The processing of first determination mode 111a, second determination mode 111b, and third determination mode 111c will be described later with reference to FIGS. 5(a) to 6.

[0025] Communication unit 113 communicates with bathroom remote control 12, kitchen remote control 13, heating remote control, etc. under the control of control unit 111. Control unit 111 receives data such as ON / OFF commands for each function and set temperatures transmitted from these remote controls via communication unit 113. Control unit 111 also transmits status information indicating the current status of water heater 11 to each remote control via communication unit 113 as needed. The status information includes the detection results by detection unit 114.

[0026] Detection unit 114 includes various sensors arranged in water heater 11. For example, detection unit 114 includes thermistors S1 to S9 (see FIG. 3) for detecting the temperature of hot water flowing through the corresponding pipes. Driving unit 115 includes driving devices for operating water heater 11 with the corresponding functions, such as flow control valves 217 and 218 (see FIG. 3) for adjusting the flow rate of hot water flowing through the pipes, solenoid valves, proportional valves, etc.

[0027] Display unit 116 is composed of, for example, a plurality of 8-segment displays. Display unit 116 is used, for example, to display errors that have occurred in water heater 11 using numbers and symbols. Display unit 116 may be another display such as a liquid crystal display. Sound output unit 117 is composed of a sound generator such as a speaker or buzzer. For example, it is used to notify the user that an error has occurred in water heater 11 by chiming or buzzing.

[0028] FIG. 3 is a diagram showing a schematic configuration of the combustion system and piping of water heater 11. As shown in FIG.

[0029] Water heater 11 includes first supply unit 210 and second supply unit 220 within housing 200 that forms its outer shell. For the hot water supply function, first supply unit 210 generates hot water for hot water supply and supplies it to hot water supply terminals such as a faucet and a bathtub. For the heating function, which includes floor heating, room heating, and bathroom heating, second supply unit 220 generates hot water for heating and supplies it to a heating terminal such as a floor heater. Furthermore, for the reheating function, second supply unit 220 generates hot water for reheating and supplies it to the bathtub.

[0030] Furthermore, housing 200 houses can body 250, which constitutes a combustion chamber, and fan 260 for supplying air for combustion into can body 250. Exhaust port 251 of can body 250 is led to the outside from the top surface of housing 200.

[0031] The first supply section 210 includes a primary heat exchanger 211, a secondary heat exchanger 212, and a combustor 213. The combustor 213 is a gas burner that burns fuel gas. The combustor 213 constitutes a heating section. The primary heat exchanger 211 and the secondary heat exchanger 212 recover heat (combustion heat) from the combustion gas generated in the combustor 213, and heat and increase the temperature of water flowing through a water inlet pipe 214. Water from a water source is supplied to the water inlet pipe 214. Hot water generated by heat exchange in the primary heat exchanger 211 and the secondary heat exchanger 212 is discharged from a hot water outlet pipe 215. The discharged hot water is supplied to faucets in the kitchen and bathroom.

[0032] A bypass pipe 216 is provided between the water inlet pipe 214 and the hot water outlet pipe 215. A flow rate control valve 217 controlled by the control unit 111 is provided in this bypass pipe 216. When the flow rate control valve 217 is opened, water flows from the water inlet pipe 214 to the hot water outlet pipe 215 via the bypass pipe 216. In this way, the water mixes with the hot water flowing through the hot water outlet pipe 215, thereby adjusting the temperature of the hot water. The hot water temperature can also be adjusted by adjusting the flow rate of the hot water flowing through the water inlet pipe 214 and the hot water outlet pipe 215 using a flow rate control valve 218 provided in the hot water outlet pipe 215. The flow rate control valve 218 may be provided in the water inlet pipe 214.

[0033] Fuel gas is supplied to the combustor 213 via a gas pipe 271. A main gas solenoid valve 272 for switching the supply and cut-off of fuel gas is installed in the gas pipe 271. The main gas solenoid valve 272 is controlled by the control unit 111. The gas pipe 271 branches into two flow paths 271a and 271b downstream of the main gas solenoid valve 272. Proportional valves 273 and 274 for controlling the flow rate of fuel gas are installed in the flow paths 271a and 271b, respectively. The proportional valves 273 and 274 are controlled by the control unit 111.

[0034] The flow paths 271a and 271b are connected to the combustors 213 and 223, respectively. When the main gas solenoid valve 272 is opened, the fuel gas at a flow rate determined by the proportional valves 273 and 274 is supplied to the combustors 213 and 223. As a result, the combustors 213 and 223 perform combustion at a predetermined combustion rate.

[0035] The second supply unit 220 includes a primary heat exchanger 221, a secondary heat exchanger 222, and a combustor 223. The combustor 223 is a gas burner that burns fuel gas. The combustor 223 constitutes a heating unit. The primary heat exchanger 221 and the secondary heat exchanger 222 recover heat from the combustion gas generated in the combustor 223 and heat the water flowing through the flow pipes 234 and 233, respectively.

[0036] Regarding the heating function, hot water dispensed from circulation pipe 231 is supplied to heating terminals that require relatively high temperature hot water (for example, about 80°C), i.e., an indoor heater and a bathroom ventilating / dryering heater. Hot water dispensed from circulation pipe 232 is supplied to heating terminals that require relatively low temperature hot water (for example, about 60°C), i.e., a floor heater. The hot water circulated through these heating terminals is returned to circulation pipe 233. In other words, circulation pipes 231, 232, and 233, the piping connecting these circulation pipes to the heating terminals, and circulation pipes 234 and 235 form a circulation path between the heating terminals.

[0037] An expansion tank 236 and a pump 237 are installed to circulate hot water between the heating flow path and the heating terminals. When the pump 237 is driven by the control unit 111, the hot water in the expansion tank 236 is introduced into each heating terminal through the circulation pipes 231 and 232, and the hot water that has passed through each heating terminal is returned to the circulation pipe 233. The hot water returned to the circulation pipe 233 is heated in the secondary heat exchanger 222 and stored in the expansion tank 236.

[0038] The low-temperature hot water stored in the expansion tank 236 is supplied to the low-temperature heating terminal through the circulation pipe 232. The low-temperature hot water stored in the expansion tank 236 is also circulated through the circulation pipe 234 to the primary heat exchanger 221, where it is heated to high-temperature hot water. The high-temperature hot water is then supplied to the high-temperature heating terminal through the circulation pipe 231. At this time, the flow rate control valve 238 installed in the circulation pipe 235 is opened by the control unit 111 as appropriate. This causes the low-temperature hot water in the expansion tank 236 to mix with the high-temperature hot water flowing through the circulation pipe 231, and the temperature of the hot water discharged from the circulation pipe 231 is adjusted. In this way, low-temperature or high-temperature hot water is circulated between each heating terminal and the primary heat exchanger 221 and the secondary heat exchanger 222. In addition, the circulation pipes 231 and 232 are provided with on-off valves (not shown), and when hot water is supplied only to the high-temperature heating terminal, the on-off valve of the circulation pipe 232 for low temperatures is closed, and when hot water is supplied only to the low-temperature heating terminal, the on-off valve of the circulation pipe 231 for high temperatures is closed.

[0039] Regarding the reheating function, hot water discharged from circulation pipe 241 is supplied to the bathtub and then returned from the bathtub to circulation pipe 243. In other words, circulation pipes 241, 242 and the piping connecting these circulation pipes to the bathtub form a circulation path between the bathtub and the hot water. A pump 244 is installed in circulation pipe 242 to circulate the hot water between the bathtub and the circulation pipe. Furthermore, a liquid-liquid heat exchanger 245 is installed in circulation pipe 242 to exchange heat with the hot water flowing through circulation pipe 243.

[0040] During reheating, the control unit 111 drives the pump 237 and opens the on-off valve 246. As a result, the hot water heated in the primary heat exchanger 221 flows through the circulation pipe 243, and the hot water flowing through the circulation pipe 242 is heated and raised in temperature by the liquid-liquid heat exchanger 245. The heated hot water is supplied to the bathtub by driving the pump 244. In this way, the hot water circulating between the bathtub and the circulation pipes 241, 242 is heated and raised in temperature by the liquid-liquid heat exchanger 245, thereby reheating the hot water in the bathtub.

[0041] For the filling function, the hot water flowing through the hot water outlet pipe 215 is diverted to a circulation pipe 247 branching off from the hot water outlet pipe 215, and is guided to the circulation pipe 242 by a hot water pouring unit 248 arranged in the circulation pipe 247. The hot water pouring unit 248 is controlled by the control unit 111, and when the filling function is being performed, it guides the hot water diverted from the hot water outlet pipe 215 to the circulation pipe 247 to the circulation pipe 242. The hot water guided to the circulation pipe 242 is supplied to the bathtub by driving the pump 244. In this way, the hot water produced in the first supply unit 210 is supplied to the bathtub, and the bathtub is filled with water.

[0042] Various sensors for executing the hot water supply operation are also installed inside the housing 200. That is, nine thermistors S1 to S9 (temperature sensors) are installed inside the housing 200.

[0043] Thermistor S1 detects the temperature of hot water immediately before it is dispensed from hot water outlet pipe 215, and thermistor S2 detects the temperature of hot water flowing through hot water outlet pipe 215 near the outlet of water heater body 250 as the hot water supply temperature. Thermistors S3 and S4 detect the temperature of hot water immediately before it is dispensed from circulation pipes 231 and 232 to the respective heating terminals, and thermistor S5 detects the temperature of hot water returned from the respective heating terminals to circulation pipe 233. Thermistor S6 detects the temperature of hot water immediately before it is dispensed from circulation pipe 241 to the bathtub, and thermistor S7 detects the temperature of hot water returned from the bathtub to circulation pipe 242. Thermistor S8 detects the temperature near exhaust port 251. Thermistor S9 detects the temperature of hot water flowing through circulation pipe 231 near the outlet of water heater body 250.

[0044] In addition, a flow rate sensor S10 for detecting the flow rate of hot water flowing through the hot water outlet pipe 215 is installed inside the housing 200. When the operation is on, if the flow rate sensor S10 detects a flow rate equal to or greater than a predetermined amount, the control unit 111 activates the first supply unit 210. This starts the hot water supply operation of the hot water supply function.

[0045] In addition, heaters H1 and H2 are arranged near the boiler body 250 of the water inlet pipe 214 and the hot water outlet pipe 215 to heat the water inlet pipe 214 and the hot water outlet pipe 215. In addition, heaters H3 and H4 are arranged near the boiler body 250 of the circulation pipes 233 and 234 to heat the circulation pipes 233 and 234.

[0046] These heaters are driven during anti-freeze operation. That is, when the temperature detected by thermistor S8 falls below a predetermined threshold, control unit 111 drives heaters H1 to H4 to prevent freezing of primary heat exchangers 211, 221 and secondary heat exchangers 212, 222. In addition, when the temperature detected by a temperature sensor (not shown) for detecting outside air temperature falls below a predetermined threshold, control unit 111 circulates hot water in the bathtub through the pipe connecting water heater 11 and the bathtub to prevent this pipe from freezing.

[0047] In water heater 1 having the above configuration, it is possible that hot water may not circulate properly through the circulation path between the heating terminal and the heater due to some cause (freezing of the circulation path, foreign matter being trapped, air being trapped, etc.). If combustion operation continues in this state, the temperature inside canister 250 may become excessively high, which may damage canister 250. For this reason, it is preferable to detect poor circulation of hot water as early as possible after combustion has started and to promptly stop the combustion operation.

[0048] Therefore, in this embodiment, a control is performed to quickly and accurately detect poor circulation of hot and cold water in the circulation path. This control will be described below.

[0049] FIG. 4 is a graph showing the change in temperature detected by thermistor S9 when second supply unit 220 is operated to perform the room heating function or the bathroom heating function.

[0050] In the example of Fig. 4, the pump 237 is driven from time 0, and hot water is circulated through the circulation path between the heating terminal and the combustion chamber 223 via the circulation pipes 231 and 233. Thereafter, combustion operation is performed by the combustor 223 from time Ts to time Te. After time Te, a post-purge process is performed to remove remaining combustion gas. In the post-purge, the fan 260 continues to be driven during the combustion operation, but the pump 237 is stopped.

[0051] During the series of operations described above, the temperature detected by thermistor S9 and the degree of temperature rise are detected. These detection results are shown as a graph in Figure 4. Here, the degree of temperature rise is calculated as the temperature difference between the temperature detected by thermistor S9 at each time and the temperature detected by thermistor S9 a predetermined time before that time (for example, 2 seconds before) (the former detected temperature - the latter detected temperature).

[0052] Figure 4 shows graphs for when hot water circulates normally through the circulation path, and graphs for when an abnormality occurs in the circulation of hot water through the circulation path (when there is almost no circulation). The top two graphs show the change in the detected temperature of thermistor S9 under normal and abnormal conditions, and the bottom two graphs show the change in the temperature difference under normal and abnormal conditions.

[0053] Referring to the two graphs on the bottom, it can be seen that the change in the temperature difference at the location of thermistor S9 during normal and abnormal conditions is significantly different, as shown below.

[0054] (1) For a few seconds after the start of combustion (time Ts), the temperature difference under normal conditions continues to rise for about 5 seconds after the start of combustion (time Ts), and then gradually approaches zero, but the temperature difference under abnormal conditions is essentially zero.

[0055] (2) In the period from the start of combustion (time Ts) to the end of combustion (time Te), the temperature difference changes little under normal conditions, but the temperature difference increases or decreases greatly under abnormal conditions.

[0056] (3) During the post-purge period after the end of combustion (time Te), the temperature difference in normal conditions is maintained at around 0, but the temperature difference in abnormal conditions increases and decreases significantly and sharply.

[0057] Therefore, from the differences (1) to (3) above, it can be determined whether the circulation of hot water and cold water in the circulation path is normal or not.

[0058] That is, from the above (1), when the pump 237 is operating, if the temperature difference (degree of increase) in the detected temperature of thermistor S9 is less than the first threshold value α (first judgment condition) immediately after the start of the combustion operation of the combustor 223), that is, within the range of a first time t1 (for example, 5 seconds) from the start of the combustion operation (time Ts), then there is a possibility that poor circulation has occurred.

[0059] Furthermore, from the above (2), if the temperature difference (degree of increase) of the detected temperature of the thermistor S9 is equal to or greater than the second threshold value β (second determination condition) during the combustion operation of the combustor 223, there is a possibility that poor circulation has occurred.

[0060] Furthermore, from (3) above, if the temperature difference (degree of increase) of the detected temperature of thermistor S9 is equal to or greater than the third threshold value γ (third judgment condition) after the combustion operation of combustor 223 is stopped, there is a possibility that poor circulation has occurred.

[0061] Here, the first threshold value α may be set to about 2°C, taking into account a variation of ±1°C in the detection resolution (e.g., 0.5°C) of the thermistor S9. The second threshold value β may be set by adding a margin of greater than 1 for detecting an abnormality to the maximum temperature difference that can occur during normal operation (the temperature difference that can occur when the combustion chamber 223 is operated at maximum capacity with the circulation flow rate at its minimum). The third threshold value γ may be set based on the temperature difference obtained during dry firing.

[0062] In this embodiment, in order to quickly and accurately detect poor circulation of hot and cold water in the circulation path, the determinations based on the differences (1) to (3) above are performed in parallel to obtain a determination result of poor circulation.

[0063] That is, the control program stored in the storage unit 112 provides the control unit 111 with the functions of a first determination mode 111a, a second determination mode 111b, and a third determination mode 111c.

[0064] In the first determination mode 111a, when the first determination condition is satisfied, the count value is incremented by 1 and the combustion operation is stopped. In the second determination mode 111b, when the second determination condition is satisfied, the count value is incremented by 1 and the combustion operation is stopped. In the third determination mode 111c, when the third determination condition is satisfied, the count value is incremented by 1.

[0065] Then, when the control unit 111 stops the combustion operation in the first determination mode 111a or the second determination mode 111b, if the count value is not equal to or greater than a predetermined threshold value Th1 (for example, 3), it resumes the combustion operation upon completion of the third determination mode 111c, and determines that poor circulation of hot water has occurred in the circulation path because the count value has become equal to or greater than the threshold value Th1.

[0066] FIG. 5(a) is a flowchart showing the processing of the control unit 111 in the first determination mode 111a.

[0067] In first determination mode 111a, when the combustion operation (heating operation) of combustor 223 (heating unit) starts (S11: YES), control unit 111 determines whether the temperature difference ΔT1 of thermistor S9 has remained less than first threshold value α for a first time t1 (e.g., 5 seconds) thereafter (S12). During the combustion operation, fan 260 is driven to introduce air into can body 250. If the determination in step S12 is NO, control unit 111 ends the processing of first determination mode 111a.

[0068] On the other hand, if the determination in step S12 is YES, the control unit 111 increments the built-in counter by 1 (S13) and stops the combustion operation of the combustor 223 (S14). As a result, the control unit 111 ends the processing of the first determination mode 111a. Thereafter, the control unit 111 returns the processing to step S11 and executes the processing of the first determination mode 111a again.

[0069] FIG. 5(b) is a flowchart showing the processing of the control unit 111 in the second determination mode 111b.

[0070] In the second determination mode 111b, while the combustor 223 is in combustion operation (S21: YES), the control unit 111 determines whether the temperature difference ΔT1 of the thermistor S9 remains equal to or greater than the second threshold value β for a second time t2 (e.g., 3 seconds) (S22). If the determination in step S22 is NO, the control unit 111 returns the process to step S21. Thereafter, the control unit 111 repeatedly performs the determination in step S22 as long as the combustor 223 is in combustion operation (S21: YES). During this time, if the combustion operation is stopped in step S14 of FIG. 5(a) (S21: NO), for example, the control unit 111 terminates the process of the second determination mode 111b.

[0071] On the other hand, if the determination in step S22 becomes YES during the combustion operation of the combustor 223 (S21: YES), the control unit 111 increments the counter by 1 (S23) and stops the combustion operation of the combustor 223 (S24). As a result, the control unit 111 ends the processing of the second determination mode 111b. Thereafter, the control unit 111 returns the processing to step S21 and executes the processing of the second determination mode 111b again.

[0072] FIG. 6 is a flowchart showing the processing of the control unit 111 in the third determination mode 111c.

[0073] In the third determination mode 111c, when the combustion operation of the combustor 223 stops due to step S14 of Figure 5(a) or step S24 of Figure 5(b) or the like (S31: YES), the control unit 111 determines whether the state in which the temperature difference ΔT1 of the thermistor S9 is equal to or greater than the third threshold value γ has continued for a third time t3 (for example, 1 second) (S32).

[0074] If the determination in step S32 is NO, the control unit 111 repeatedly executes the processing of step S32 until the post-purge operation after the combustion operation has stopped is completed (S34: NO). Here, the post-purge operation refers to an operation of operating the fan 260 for a certain period of time to introduce outside air into the can body 250 and ventilate the inside of the can body 250 in order to remove residual combustion gases from the can body 250.

[0075] If the determination in step S32 becomes YES during the post-purge operation (S34: NO), the control unit 111 increments the counter by 1 (S33) and terminates the processing of the third determination mode 111c. If the determination in step S32 does not become YES and the post-purge operation terminates (S34: YES), the control unit 111 terminates the processing of the third determination mode 111c. Thereafter, the control unit 111 returns the processing to step S31 and executes the processing of the third determination mode 111c again.

[0076] FIG. 7 is a flowchart showing the process of determining whether or not there is a poor circulation of hot and cold water in the circulation path.

[0077] When the operation of the room heating function or the bathroom heating function is started, the control unit 111 executes the processes of the first determination mode 111a, the second determination mode 111b, and the third determination mode 111c in parallel, and further executes the determination process of FIG. 7 in parallel.

[0078] 7, the control unit 111 determines whether the counter value is equal to or greater than the threshold value Th1 (S41). If the determination in step S41 is NO, the control unit 111 determines whether the combustion operation of the combustor 223 is stopped (S42) by step S14 in FIG. 5(a) or step S24 in FIG. 5(b), etc. If the combustion operation is stopped (S42: YES), and if the operation of the heating function has not ended (S43: YES), the control unit 111 restarts the combustion operation of the combustor 223 in response to the end of the third determination mode 111c (S44), and returns the process to step S41.

[0079] If the determination in step S42 is NO, control unit 111 returns the process to step S41. If the determination in step S43 is NO, control unit 111 ends the determination process of Fig. 7. In this case, control unit 111 also ends the processes of first determination mode 111a, second determination mode 111b, and third determination mode 111c described above.

[0080] If the determination in step S41 is YES, the control unit 111 determines that the circulation of hot water in the circulation path has become poor (S45) and stops the operation of the heating function (S46). Then, the control unit 111 causes the display unit 116 and the sound output unit 117 in Fig. 2 to output a display and a sound to notify the poor circulation (S47). This causes the control unit 111 to end the determination process in Fig. 7.

[0081] In the notification process of step S47, for example, a code indicating poor circulation is displayed on display unit 116, and an alarm sound (such as a buzzer or chime) is output from sound output unit 117. In addition, control unit 111 may communicate with bathroom remote control 12 and kitchen remote control 13, and cause these remote controls to output a display and a sound to notify of poor circulation.

[0082] When poor circulation occurs in the circulation path, first, the judgment condition (S12) of the first judgment mode 111a in Fig. 5(a) is satisfied, the counter is incremented by 1 (S13), and the combustion operation is stopped (S14). In this case, the judgment conditions (S22, S32) of the second judgment mode 111b and the third judgment mode 111c are not usually satisfied, and no increment occurs in the counter.

[0083] Thereafter, when the combustion operation is resumed in step S44 of Fig. 7, the determination condition (S12) of the first determination mode 111a of Fig. 5(a) is satisfied again, 1 is incremented to the counter (S13), and the combustion operation is stopped (S14). When the combustion operation is resumed again thereafter, the determination condition (S12) of the first determination mode 111a is satisfied again, 1 is incremented to the counter (S13), and the combustion operation is stopped (S14). In this way, when only the determination condition of the first determination mode 111a is satisfied three times in a row, step S41 of Fig. 7 becomes YES, and poor circulation is detected (S45).

[0084] In this case, the combustion operation of the combustor 223 is limited to a total of t1 × 3 (approximately 15 seconds) by repeating the first time t1 (for example, 5 seconds) in step S12 of Fig. 5(a) three times. Therefore, poor circulation can be detected quickly and accurately from the start of the initial combustion, and damage to the boiler body 250 can be minimized.

[0085] Furthermore, if the determination condition (S12) for first determination mode 111a is not satisfied after the combustion operation is resumed, the determination condition (S22) for second determination mode 111b is satisfied and 1 is added to the counter (S23), and then, when the combustion operation is stopped (S24), the determination condition (S32) for third determination mode 111c is satisfied and 1 is added to the counter (S33). As a result, the determination in step S41 in Fig. 7 becomes YES, and poor circulation is detected.

[0086] In this case, the combustion operation of the combustor 223 is limited to the sum of the first time t1 (e.g., 5 seconds) required for the determination in step S12 of Fig. 5(a) during the first combustion operation and the time required for the determination in step S22 of Fig. 5(b) to become YES during the second combustion operation. Therefore, in this case as well, poor circulation can be detected quickly and accurately from the start of the first combustion, and damage to the can body 250 can be effectively suppressed.

[0087] Furthermore, if the determination condition (S12) for first determination mode 111a is not satisfied at the start of the initial combustion operation, the determination condition (S22) for second determination mode 111b is satisfied, and 1 is added to the counter (S23). Then, when the combustion operation is stopped (S24), the determination condition (S32) for third determination mode 111c is satisfied, and 1 is added to the counter (S33). Then, after the combustion operation is resumed, the determination condition (S12) for first determination mode 111a is satisfied, and 1 is added to the counter (S13). As a result, the determination in step S41 of FIG. 7 becomes YES, and poor circulation is detected. In this case, poor circulation can be detected quickly and accurately from the start of the initial combustion, and damage to can body 250 can be effectively suppressed.

[0088] The determination conditions (S12, S22, S32) of first determination mode 111a, second determination mode 111b, and third determination mode 111c are not limited to the above-mentioned determination conditions, and may be other conditions that can be set from the graph of FIG.

[0089] For example, in the processing of the first determination mode 111a in FIG. 5(a), the determination condition for step S12 is that the temperature difference ΔT1 remains less than the first threshold value α for a first time t1 from the start of the combustion operation. Alternatively, the determination condition for step S12 may be that the temperature difference ΔT1 remains less than the first threshold value α at at least one time (e.g., 5 seconds after time Ts) included in a time range immediately after the start of the combustion operation (e.g., a range of approximately 10 seconds from time Ts).

[0090] 5(b), the determination condition for step S22 is that the state in which the temperature difference ΔT1 is equal to or greater than the second threshold value β continues for the second time t2, but instead, the determination condition for step S22 may be that a state in which the temperature difference ΔT1 is equal to or greater than the second threshold value β occurs during the combustion operation. In this case, too, by setting the second threshold value β to a value somewhat larger than the maximum expected value (approximately 12°C in FIG. 4) of the temperature difference ΔT1 in the normal state shown by the dashed line in the lower part of FIG. 4, it is possible to properly determine the occurrence of a temperature difference in the abnormal state (poor circulation) shown by the solid line in the lower part of FIG.

[0091] Furthermore, in the processing of the third determination mode 111c in FIG. 6, the determination condition in step S32 is that the state in which the temperature difference ΔT1 is equal to or greater than the third threshold value γ continues for the third time t3. Alternatively, the determination condition in step S32 may be that a state in which the temperature difference ΔT1 is equal to or greater than the third threshold value γ occurs after the combustion operation has stopped (during the post-purge operation).

[0092] These determination methods can quickly and accurately detect poor circulation of hot water in the circulation path, as in the above embodiment. However, in the determination method of the above embodiment, the determination condition is that the temperature difference ΔT1 continues to satisfy each threshold condition during the first time t1, the second time t2, and the third time t3, so poor circulation of hot water in the circulation path can be detected more accurately and stably than with the determination condition changed as described above.

[0093] <Effects of the embodiment> According to the embodiment, the following effects can be achieved.

[0094] As shown in Figures 2 and 3, the water heater 11 (heating device) includes a primary heat exchanger 221 that generates hot water by heating with a combustor 223 (heating section), a pump 237 that circulates the hot water generated by the primary heat exchanger 221 through a circulation path consisting of a circulation pipe 231 (feed path) and a circulation pipe 233 (return path), a thermistor S9 (temperature sensor) that detects the temperature of the circulation pipe 231 (feed path) near the primary heat exchanger 221, and a control unit 111 that determines poor circulation of the hot water in the circulation path based on the detected temperature of the thermistor S9 (temperature sensor) while the pump 237 is operating. The control unit 111 is equipped with a first determination mode 111a in which, based on the temperature difference ΔT1 (degree of increase) of the detected temperature immediately after the start of the combustion operation (heating operation) of the combustor 223 (heating unit), 1 is added to the count value to stop the combustion operation, a second determination mode 111b in which, based on the temperature difference ΔT1 (degree of increase) of the detected temperature during the combustion operation of the combustor 223 being equal to or greater than a second threshold value β, 1 is added to the count value to stop the combustion operation, and a third determination mode 111c in which, based on the temperature difference ΔT1 (degree of increase) of the detected temperature being equal to or greater than a third threshold value γ after the combustion operation of the combustor 223 is stopped, 1 is added to the count value. When the combustion operation is stopped in the first determination mode 111a or the second determination mode 111b, if the count value is not equal to or greater than a predetermined threshold value Th1 (S41: NO), the control unit 111 resumes the combustion operation (S44), and if the count value is equal to or greater than the threshold value Th1 (S41: YES), it determines that poor circulation has occurred (S45).

[0095] According to this configuration, as described above, the total time of the combustion operation until the count value reaches or exceeds the threshold value and poor circulation is detected can be effectively reduced, and poor circulation can be accurately detected.

[0096] As shown in Figures 5(a), (b) and 6, in the first determination mode 111a, if the temperature difference ΔT1 (degree of increase) is maintained below the first threshold value α for a first time t1 from the start of the combustion operation (S12: YES), the control unit 111 adds 1 to the count value (S13), in the second determination mode 111b, if the temperature difference ΔT1 (degree of increase) is equal to or greater than the second threshold value β for a second consecutive time t2 (S22: YES), the control unit 111 adds 1 to the count value, and in the third determination mode 111c, if the temperature difference ΔT1 (degree of increase) is equal to or greater than the third threshold value γ for a third consecutive time t3 (S32: YES), the control unit 111 adds 1 to the count value (S33).

[0097] According to this configuration, the judgment condition for each judgment mode is that the degree of increase continues to satisfy each threshold condition at the first time t1, the second time t2, and the third time t3, so that poor circulation of hot water in the circulation path can be detected more accurately and stably.

[0098] <Example of change> In the above embodiment, the water heater 11 has a floor heating function, a room heating function, and a bathroom heating function, but for example, the water heater 11 does not have to have a floor heating function, or the configuration of the above embodiment may be applied to a circulation path for performing the floor heating function. Also, if the water heater 11 has a hot and cold water circulation path for a function other than these heating functions, the configuration of the above embodiment may be applied to this circulation path.

[0099] Furthermore, in the above embodiment, the method of acquiring the temperature difference ΔT1 used in the judgments of steps S12, S22, and S32 was the same, but the method of acquiring the temperature difference used in the judgments of steps S12, S22, and S32 (how to determine the difference between the current detected temperature and the detected temperature at a time some time ago) may be different from each other.

[0100] Furthermore, in the above embodiment, each determination mode is provided in the control unit 111 of the water heater 11, and the control unit 111 performs the determination process of Fig. 7, but these processes may be performed by a control device other than the water heater 11. For example, each determination mode may be provided in the control unit of the kitchen remote control 13, and the control unit may perform the determination process of Fig. 7. In this case, the water heater 11 and the kitchen remote control 13 constitute the heating device described in the claims. Furthermore, the processing of each determination mode and the determination process of Fig. 7 may be shared between the control unit 111 of the water heater 11 and another control device.

[0101] Furthermore, in the above embodiment, the water heater 1 is a gas combustion water heater that heats water with combustion gas generated by burning gas fuel, but the configuration of the water heater 1 is not limited to this. For example, the water heater 1 may be a cogeneration water heater that, together with the water heater 11, generates hot water using exhaust heat from a generator that generates electricity. Alternatively, the water heater 11 of the water heater 1 may be an oil combustion water heater that heats water with combustion gas generated by burning oil fuel, or a heat pump water heater that heats water with heat from a heat pump. In other words, the heating unit is not limited to a gas burner, and may be configured to heat water using other methods.

[0102] Furthermore, the configuration of the combustion system and piping of water heater 11 is not limited to the configuration shown in FIG. 3, and other configurations may be used.

[0103] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the claims. [Explanation of symbols]

[0104] 10. Hot water supply equipment 11 Water heater (heating device) 111 Control Unit 111a First judgment mode 111b Second judgment mode 111c Third Judgment Mode 112 Storage section 221 Primary heat exchanger 222 Secondary heat exchanger 223 Combustor (heating section) 237 Pump S9 Thermistor (Temperature Sensor)

Claims

1. a heat exchanger that generates hot water by heating using a heating unit; a pump that circulates the hot water generated by the heat exchanger through a circulation path consisting of a feed path and a return path; a temperature sensor for detecting the temperature of the feed path near the heat exchanger; a control unit that determines whether the hot water circulation in the circulation path is poor based on the temperature detected by the temperature sensor while the pump is operating, The control unit a first determination mode in which, based on the fact that the degree of increase in the detected temperature immediately after the start of the heating operation of the heating unit is less than a first threshold, one is added to the count value and the heating operation is stopped; a second determination mode in which, when the degree of increase in the detected temperature during the heating operation of the heating unit is equal to or greater than a second threshold, one is added to the count value and the heating operation is stopped; a third determination mode in which, after the heating operation of the heating unit is stopped, one is added to the count value based on the degree of increase in the detected temperature being equal to or greater than a third threshold value; When the heating operation is stopped in the first determination mode or the second determination mode, if the count value is not equal to or greater than a predetermined threshold, the heating operation is resumed, and when the count value becomes equal to or greater than the threshold, it is determined that the poor circulation has occurred. A heating device characterized by:

2. 2. The heating device according to claim 1, The control unit In the first determination mode, when the degree of increase is maintained below the first threshold value for a first time period from the start of the heating operation, adding 1 to a count value; In the second determination mode, when the degree of increase is equal to or greater than the second threshold value for a second consecutive time, 1 is added to the count value; In the third determination mode, when the degree of increase is equal to or greater than the third threshold value for a third consecutive time, 1 is added to the count value. A heating device characterized by:

Images