Heating system

Abstract

To provide a technique capable of determining whether or not a detection failure occurs in a secondary supply temperature sensor.SOLUTION: The heating system includes a heat source machine for heating a heat medium, a heating terminal for heating by heat radiation from the heat medium, a heating circuit including a primary forward flow path to which the heat medium is sent from the heat source machine, a primary return flow path to which the heat medium is sent from the heating terminal, a secondary forward flow path to which the heat medium is sent to the heating terminal, and a secondary return flow path from which the heat medium is sent to the heating terminal, a fluid mixer for fluidly connecting each of a downstream end of the primary return flow path, an upstream end of the primary return flow path, a downstream end of the secondary forward flow path, and an upstream end of the secondary return flow path, and a primary return temperature sensor for detecting a temperature of the heat medium flowing in the primary return flow path, and a secondary return temperature sensor for detecting a temperature of the heat medium flowing in the secondary forward flow path. The control unit determines whether a detection failure has occurred in the secondary supply temperature sensor on the basis of the temperature detected by the primary return temperature sensor and the temperature detected by the secondary supply temperature sensor.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The technology disclosed herein relates to heating systems. [Background technology]

[0002] Patent Document 1 discloses a heating system comprising: a heat source machine that heats a heat medium; a heating terminal that heats by heat radiation from the heat medium; a heating circuit including a primary forward flow path that sends the heat medium to the heat source machine; a primary return flow path through which the heat medium is sent from the heat source machine; a secondary forward flow path that sends the heat medium to the heating terminal; and a secondary return flow path through which the heat medium is sent from the heating terminal; a fluid mixer that fluidly connects the upstream end of the primary forward flow path, the downstream end of the primary return flow path, the upstream end of the secondary forward flow path, and the downstream end of the secondary return flow path; a primary return temperature sensor that detects the temperature of the heat medium flowing in the primary return flow path; a secondary forward temperature sensor that detects the temperature of the heat medium flowing in the secondary forward flow path; and a control unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2016 / 0116185 Summary of the Invention [Problem to be solved by the invention]

[0004] In a heating system, a detection failure may occur in a secondary forward temperature sensor. The detection failure here refers to, for example, a discrepancy between the actual temperature of the heat transfer medium flowing through the secondary forward flow path and the temperature detected by the secondary forward temperature sensor. This specification provides a technology that can determine whether a detection failure has occurred in the secondary forward temperature sensor. [Means for solving the problem]

[0005] In a first aspect of the present technology, a heating system may include a heat source device that heats a heat medium, a heating terminal that performs heating by heat radiation from the heat medium, a heating circuit including a primary forward flow path through which the heat medium is sent from the heat source device, a primary return flow path that sends the heat medium to the heat source device, a secondary forward flow path that sends the heat medium to the heating terminal, and a secondary return flow path through which the heat medium is sent from the heating terminal, a fluid mixer that fluidly connects a downstream end of the primary forward flow path to an upstream end of the primary return flow path, an upstream end of the secondary forward flow path, and a downstream end of the secondary return flow path, a primary return temperature sensor that detects the temperature of the heat medium flowing in the primary return flow path, a secondary forward temperature sensor that detects the temperature of the heat medium flowing in the secondary forward flow path, and a controller. The controller may determine whether a detection failure has occurred in the secondary forward temperature sensor based on the detected temperatures of the primary return temperature sensor and the secondary forward temperature sensor.

[0006] According to the above configuration, the control unit can determine whether or not a detection failure has occurred in the secondary forward temperature sensor based on the detected temperature of the primary return temperature sensor and the detected temperature of the secondary forward temperature sensor.

[0007] In a second aspect of the present technology, in the first aspect, the heating system may include a plurality of the heat source machines and a plurality of the primary return temperature sensors corresponding to the plurality of the heat source machines. The control unit may determine whether or not a detection failure has occurred in the secondary forward temperature sensor based on a detected temperature of one of the plurality of primary return temperature sensors and a detected temperature of the secondary forward temperature sensor.

[0008] When determining whether a detection failure has occurred in the secondary forward temperature sensor, the control unit can also refer to the temperatures detected by two or more primary return temperature sensors. However, doing so may complicate the processing performed by the control unit. With the above configuration, when determining whether a detection failure has occurred in the secondary forward temperature sensor, it is sufficient for the control unit to refer to the temperature detected by one primary return temperature sensor. This allows the processing performed by the control unit to be relatively simplified.

[0009] In a third aspect of the present technology, in the first aspect, the heating system may include a plurality of the heat source units and a plurality of the primary return temperature sensors corresponding to the plurality of the heat source units. The control unit may determine whether a detection failure has occurred in the secondary forward temperature sensor based on the detected temperatures of two or more of the primary return temperature sensors among the plurality of the primary return temperature sensors and the detected temperature of the secondary forward temperature sensor.

[0010] According to the above configuration, when determining whether a detection failure has occurred in the secondary forward temperature sensor, the control unit can refer to the detected temperatures of two or more primary return temperature sensors. This allows for a more accurate determination of whether a detection failure has occurred in the secondary forward temperature sensor, compared to a configuration in which the control unit refers to the detected temperature of a single primary return temperature sensor. For example, a primary return temperature sensor that detects an abnormal temperature compared to the others (i.e., a primary return temperature sensor with a detection failure) may be included among the multiple primary return temperature sensors. If the control unit were configured to refer to the detected temperature of only one primary return temperature sensor, the control unit would not be able to determine whether that primary return temperature sensor is detecting an abnormal temperature compared to the others. In contrast, according to the above configuration, the control unit refers to the detected temperatures of two or more primary return temperature sensors, and by comparing the detected temperatures, it can identify the primary return temperature sensor that detects an abnormal temperature compared to the others (i.e., a primary return temperature sensor with a detection failure). This allows the control unit to determine whether a detection failure has occurred in the secondary forward temperature sensor without considering the detected temperature of the primary return temperature sensor with a detection failure.

[0011] In a fourth aspect of the present technology, in any one of the first to third aspects above, the control unit may determine that a detection failure has occurred in the secondary forward temperature sensor when the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor is less than a predetermined temperature.

[0012] The secondary forward flow path carries the heat medium after it has been heated by the heat source unit but before it is radiated by the heating terminal. The primary return flow path carries the heat medium after it has radiated heat by the heating terminal but before it is heated by the heat source unit. Therefore, a high-temperature heat medium flows through the secondary forward flow path, and a low-temperature heat medium flows through the primary return flow path. Therefore, the temperature of the heat medium flowing through the secondary forward flow path (i.e., the temperature detected by the secondary forward temperature sensor) is usually higher than the temperature of the heat medium flowing through the primary return flow path (i.e., the temperature detected by the primary return temperature sensor), and there is usually a certain temperature difference between the two. However, if a detection error occurs in the secondary forward temperature sensor, the temperature detected by the secondary forward temperature sensor may be significantly lower than the actual temperature of the heat medium flowing through the secondary forward flow path. In this case, the temperature difference obtained by subtracting the temperature detected by the primary return temperature sensor from the temperature detected by the secondary forward temperature sensor is smaller than usual. With the above configuration, it is possible to determine that a detection error has occurred in the secondary forward temperature sensor in such a case. Specifically, if the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor is less than a predetermined temperature, it can be determined that a detection failure has occurred in the secondary forward temperature sensor.

[0013] In a fifth aspect of the present technology, in any one of the first to third aspects above, the control unit may determine that a detection failure has occurred in the secondary forward temperature sensor when a state in which the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor remains less than a predetermined temperature continues for more than a predetermined time.

[0014] It is also possible to determine that a detection failure has occurred in the secondary forward temperature sensor when the temperature difference obtained by subtracting the temperature detected by the primary return temperature sensor from the temperature detected by the secondary forward temperature sensor falls below a predetermined temperature. However, even if a detection failure has not occurred in the secondary forward temperature sensor, the temperature difference may fall below the predetermined temperature for a very short period of time due to other factors. A configuration that determines a detection failure when the temperature difference falls below the predetermined temperature may result in an erroneous determination in this case. With the above configuration, a detection failure in the secondary forward temperature sensor is determined only when the temperature difference remains below the predetermined temperature for a long period of time. Therefore, if the temperature difference falls below the predetermined temperature for only a very short period of time, a detection failure is not determined. This prevents erroneous determination of whether a detection failure has occurred in the secondary forward temperature sensor.

[0015] In a sixth aspect of the present technology, in any one of the first to fifth aspects, the control unit may be capable of executing a first process to control the heating capacity of the heat source unit based on the temperature detected by the secondary forward temperature sensor. When it is determined that a detection failure has occurred in the secondary forward temperature sensor, the control unit may not execute the first process.

[0016] If the heating capacity of the heat source machine is controlled based on a secondary forward temperature sensor that has a detection failure, the heating capacity of the heat source machine may become excessively high. With the above configuration, it is possible to prevent the heating capacity of the heat source machine from being controlled based on a secondary forward temperature sensor that has a detection failure. This prevents the heating capacity of the heat source machine from becoming excessively high.

[0017] In a seventh aspect of the present technology, in the sixth aspect, the control unit may further execute a second process to control the heating capacity of the heat source unit without being based on the temperature detected by the secondary forward temperature sensor. The control unit may execute the second process when it is determined that a detection failure has occurred in the secondary forward temperature sensor.

[0018] According to the above configuration, the control unit can control the heating capacity of the heat source unit by executing the second process without relying on the temperature detected by the secondary forward temperature sensor. As a result, even if a detection error occurs in the secondary forward temperature sensor, the heating capacity of the heat source unit can be controlled without being affected by this. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic configuration diagram of a heating system 2 according to an embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating a fluid mixer 20 of the heating system 2 according to the embodiment. [Figure 3] 4 is a diagram showing the flow of the heat medium when a first heating operation is performed in the heat source unit 100 of the heating system 2 according to the embodiment. FIG. [Figure 4] 5 is a diagram showing the flow of the heat medium when a second heating operation is performed in the heat source apparatus 100 of the heating system 2 according to the embodiment. FIG. [Figure 5] 10 is a diagram showing the flow of the heat medium when the heating terminal 8a performs heating and the heat source units 400 and 500 perform a first heating operation in the heating system 2 according to the embodiment. FIG. [Figure 6] 10 is a flowchart of a process executed by a master unit control unit 102 of a heating system 2 according to the embodiment. [Figure 7] 7 is a flowchart of a first output control process executed by a master unit control unit 102 of a heating system 2 according to the embodiment in the process shown in FIG. 6. [Figure 8] 7 is a flowchart of a second output control process executed by a master unit control unit 102 of a heating system 2 according to the embodiment in the process shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0020] (Example) As shown in FIG. 1, the heating system 2 includes a hot water supply circuit 4 (some parts not shown), a heating circuit 6, five heat source units 100, 200, 300, 400, and 500, and three heating terminals 8a, 8b, and 8c. Water flows through the hot water supply circuit 4. A heat medium (e.g., water or antifreeze) flows through the heating circuit 6. The heat source units 100, 200, 300, 400, and 500 are provided in parallel with the heating circuit 6 and the hot water supply circuit 4, respectively. The heat source units 100, 200, 300, 400, and 500 heat the water flowing through the hot water supply circuit 4 and the heat medium flowing through the heating circuit 6. A faucet and a bathtub (not shown) are provided in the hot water supply circuit 4. The heating circuit 6 is provided with heating terminals 8a, 8b, and 8c in parallel. The heating terminals 8a, 8b, and 8c include, for example, floor heating devices and panel heaters. The heating terminals 8a, 8b, and 8c perform heating by radiating heat from a heat medium flowing through the heating circuit 6. The heating system 2 can supply water heated by the heat source units 100, 200, 300, 400, and 500 to a faucet or a bathtub via the hot water supply circuit 4. The heating system 2 can also cause the heating terminals 8a, 8b, and 8c to perform heating by sending the heat medium heated by the heat source units 100, 200, 300, 400, and 500 to the heating terminals 8a, 8b, and 8c via the heating circuit 6.

[0021] The heating circuit 6 includes a primary forward flow path 12 through which the heat medium is sent from each of the heat source units 100, 200, 300, 400, and 500, a primary return flow path 14 that sends the heat medium to each of the heat source units 100, 200, 300, 400, and 500, a secondary forward flow path 16 that sends the heat medium to each of the heating terminals 8a, 8b, and 8c, and a secondary return flow path 18 through which the heat medium is sent from each of the heating terminals 8a, 8b, and 8c. Fluid mixers 20 are provided between the downstream end of the primary forward flow path 12, the upstream end of the primary return flow path 14, the upstream end of the secondary forward flow path 16, and the downstream end of the secondary return flow path 18. By providing the fluid mixer 20, it is possible for a difference to occur between the flow rate of the heat medium flowing in the primary forward flow path 12 and the primary return flow path 14 (i.e., the total flow rate of the heat medium flowing in the heat source units 100, 200, 300, 400, 500) and the flow rate of the heat medium flowing in the secondary forward flow path 16 and the secondary return flow path 18 (i.e., the total flow rate of the heat medium flowing in the heating terminals 8a, 8b, 8c).

[0022] As shown in FIG. 2 , the fluid mixer 20 includes a mixer body 72, an air vent valve 74, a dust vent valve 76, a primary inlet 78 connected to the downstream end of the primary forward flow path 12, a primary outlet 80 connected to the upstream end of the primary return flow path 14, a secondary outlet 82 connected to the upstream end of the secondary forward flow path 16, and a secondary inlet 84 connected to the downstream end of the secondary return flow path 18. The mixer body 72 has a generally cylindrical shape extending between the air vent valve 74 and the dust vent valve 76. The fluid mixer 20 is disposed such that the axial direction of the mixer body 72 is aligned vertically. The fluid mixer 20 is disposed such that the air vent valve 74 is located vertically above the mixer body 72 and the dust vent valve 76 is located vertically below the mixer body 72. By opening the air vent valve 74, air accumulated in the fluid mixer 20 can be discharged to the outside of the fluid mixer 20. By opening the debris removal valve 76, debris accumulated in the fluid mixer 20 can be discharged to the outside of the fluid mixer 20. Furthermore, the primary inlet 78 and the secondary outlet 82 are arranged to face each other with the interior of the mixer body 72 interposed therebetween. This allows the heat transfer medium flowing from the primary forward flow path 12 into the primary inlet 78 to easily flow into the secondary forward flow path 16 via the secondary outlet 82. Similarly, the secondary inlet 84 and the primary outlet 80 are arranged to face each other with the interior of the mixer body 72 interposed therebetween. This allows the heat transfer medium flowing from the secondary return flow path 18 into the secondary inlet 84 to easily flow into the primary return flow path 14 via the primary outlet 80.

[0023] The primary forward flow path 12 carries a high-temperature heat transfer medium that has been heated by the heat source units 100, 200, 300, 400, and 500 but has not yet been radiated by the heating terminals 8a, 8b, and 8c. Therefore, the high-temperature heat transfer medium flows into the primary inlet 78. Furthermore, the secondary return flow path 18 carries a low-temperature heat transfer medium that has been radiated by the heating terminals 8a, 8b, and 8c but has not yet been radiated by the heat source units 100, 200, 300, 400, and 500. Therefore, the low-temperature heat transfer medium flows into the secondary inlet 84. Inside the mixer body 72, a phenomenon occurs in which the high-temperature heat transfer medium rises and the low-temperature heat transfer medium descends (so-called convection). In this embodiment, the primary inlet 78 and secondary outlet 82 are connected to the top of the mixer body 72, and the secondary inlet 84 and primary outlet 80 are connected to the bottom of the mixer body 72. This allows the high-temperature heat transfer medium flowing from the primary forward flow path 12 into the primary inlet 78 to easily flow into the secondary forward flow path 16 via the secondary outlet 82. The low-temperature heat transfer medium flowing from the secondary return flow path 18 into the secondary inlet 84 to easily flow into the primary return flow path 14 via the primary outlet 80.

[0024] The heating circuit 6 shown in Fig. 1 further includes terminal flow paths 22a, 22b, and 22c corresponding to the heating terminals 8a, 8b, and 8c, respectively. The upstream ends of the terminal flow paths 22a, 22b, and 22c are connected to the secondary forward flow path 16. The downstream ends of the terminal flow paths 22a, 22b, and 22c are connected to the secondary return flow path 18. Terminal pumps 24a, 24b, and 24c are provided in the terminal flow paths 22a, 22b, and 22c. The terminal pumps 24a, 24b, and 24c draw the heat medium from the secondary forward flow path 16 into the terminal flow paths 22a, 22b, and 22c, and deliver the heat medium from the terminal flow paths 22a, 22b, and 22c to the secondary return flow path 18. By operating the terminal pumps 24a, 24b, and 24c, the heat medium is sent to the heating terminals 8a, 8b, and 8c, and heating is performed by the heating terminals 8a, 8b, and 8c.

[0025] The heating system 2 includes thermostats 26a, 26b, and 26c corresponding to the heating terminals 8a, 8b, and 8c. The thermostats 26a, 26b, and 26c detect the temperature of the space in which the corresponding heating terminals 8a, 8b, and 8c are installed, i.e., the space heated by the heating terminals 8a, 8b, and 8c (e.g., the interior of a house). When the detected temperature falls below a predetermined heating ON threshold (e.g., 20°C), the thermostats 26a, 26b, and 26c output a heating ON signal to start heating by the heating terminals 8a, 8b, and 8c. When the detected temperature exceeds a predetermined heating OFF threshold (e.g., 25°C), the thermostats 26a, 26b, and 26c output a heating OFF signal to end heating by the heating terminals 8a, 8b, and 8c. In this specification, the heating ON signal and the heating OFF signal are collectively referred to as "heating signals."

[0026] The heat source machine 100 includes a burner 32, a first heat exchanger 34 that heats a heat medium using the combustion heat of the burner 32, a primary return branch path 36 that connects the fluid inlet of the first heat exchanger 34 and the primary return flow path 14, a primary forward branch path 38 that connects the fluid outlet of the first heat exchanger 34 and the primary forward flow path 12, a heat source pump 40 provided in the primary return branch path 36, a bypass path 42 that bypasses the first heat exchanger 34 and the heat source pump 40 and connects the primary return branch path 36 and the primary forward branch path 38, a second heat exchanger 44 that heats water flowing in the hot water supply circuit 4 by heat exchange with the heat medium flowing in the bypass path 42, and a three-way valve 46 provided at the connection between the primary forward branch path 38 and the bypass path 42. The three-way valve 46 is switchable between a first state (see FIG. 3 ) in which the heat medium flowing out of the first heat exchanger 34 is sent to the primary forward flow path 12 via the primary forward branch path 38, and a second state (see FIG. 4 ) in which the heat medium flowing out of the first heat exchanger 34 is sent to the bypass path 42 via the primary forward branch path 38. The three-way valve 46 can switch the destination of the heat medium flowing out of the first heat exchanger 34 between the bypass path 42 and the primary forward flow path 12. In addition, the primary return branch path 36 is provided with a primary return thermistor 48 that detects the temperature of the heat medium immediately before it is heated in the first heat exchanger 34. The primary forward branch path 38 is provided with a primary forward thermistor 50 that detects the temperature of the heat medium immediately after it is heated in the first heat exchanger 34.

[0027] As shown in Fig. 3, the heat source apparatus 100 is configured to be able to perform a first heating operation in which the heat medium flowing in the heating circuit 6 is heated by setting the three-way valve 46 to the first state, firing the burner 32, and operating the heat source pump 40. When the first heating operation is performed, the heat medium in the primary return flow path 14 passes through the primary return branch path 36, the first heat exchanger 34, and the primary forward branch path 38 in this order, and is then sent to the primary forward flow path 12. The heat medium is heated by the combustion heat of the burner 32 as it passes through the first heat exchanger 34.

[0028] As shown in Fig. 4, the heat source apparatus 100 is configured to be able to execute a second heating operation in which the water flowing in the hot water supply circuit 4 is heated by setting the three-way valve 46 to the second state, firing the burner 32, and operating the heat source pump 40. When the second heating operation is executed, a heat medium is circulated between the primary return branch path 36, the first heat exchanger 34, the primary forward branch path 38, and the bypass path 42 (i.e., the second heat exchanger 44). When passing through the first heat exchanger 34, the heat medium is heated by the heat of combustion of the burner 32, and when passing through the second heat exchanger 44, the heat medium is released to the water flowing in the hot water supply circuit 4. As a result, the water flowing in the hot water supply circuit 4 is heated.

[0029] The heat source device 100 further includes a heat source control unit 102 including a CPU, a ROM, a RAM, etc. The ROM stores various operating programs. The RAM temporarily stores various signals input to the heat source control unit 102 and various data generated in the process of the CPU executing processing. The heat source control unit 102 controls each component of the heat source device 100 by the CPU executing processing based on information stored in the ROM and RAM. The heat source control unit 102 can set a setting value (also referred to as an "output setting value") related to the output of the burner 32. The output setting value is set to one of five levels, for example, "1," "2," "3," "4," and "5." The heat source control unit 102 controls the output of the burner 32 based on the output setting value when burning the burner 32 (for example, when performing the first heating operation). The heat source control unit 102 increases the output of the burner 32 as the output setting value increases.

[0030] 1 include the same components as the heat source unit 100. For example, the heat source control units 202, 302, 402, 502 included in the heat source units 200, 300, 400, 500 are components corresponding to the heat source control unit 102, and control the components of the heat source units 200, 300, 400, 500. For simplification, the other components included in the heat source units 200, 300, 400, 500 are not labeled with reference numerals.

[0031] A first signal line 62a for communication with the thermostat 26a and a second signal line 64a for communication with the terminal pump 24a are connected to the heat source control unit 102 of the heat source device 100. A heating signal output by the thermostat 26a is transmitted to the heat source control unit 102 via the first signal line 62a. The heat source control unit 102 also controls the operation of the terminal pump 24a by sending instructions to the terminal pump 24a via the second signal line 64a. For example, when a heating ON signal is transmitted from the thermostat 26a, the heat source control unit 102 operates the terminal pump 24a. This starts the supply of heat medium to the heating terminal 8a corresponding to the thermostat 26a, and heating by the heating terminal 8a begins. Thereafter, when a heating OFF signal is transmitted from the thermostat 26a, the heat source control unit 102 stops the terminal pump 24a. This stops the supply of heat medium to the heating terminal 8a corresponding to the thermostat 26a, and heating by the heating terminal 8a ends.

[0032] A first signal line 62b for communicating with thermostat 26b and a second signal line 64b for communicating with terminal pump 24b are connected to the heat source control unit 202 of the heat source apparatus 200. The relationship between the heat source control unit 202, thermostat 26b, terminal pump 24b, and heating terminal 8b is similar to the relationship between the heat source control unit 102, thermostat 26a, terminal pump 24a, and heating terminal 8a described above. Furthermore, a first signal line 62c for communicating with thermostat 26c and a second signal line 64c for communicating with terminal pump 24c are connected to the heat source control unit 302 of the heat source apparatus 300. The relationship between the heat source control unit 302, thermostat 26c, terminal pump 24c, and heating terminal 8c is similar to the relationship between the heat source control unit 102, thermostat 26a, terminal pump 24a, and heating terminal 8a described above.

[0033] In this embodiment, of the heat source control units 102, 202, 302, 402, and 502, the heat source control unit 102 functions as a parent unit control unit, and the remaining heat source control units 202, 302, 402, and 502 function as child unit control units that can communicate with the parent unit control unit. Hereinafter, the heat source control unit 102 will also be referred to as the "parent unit control unit 102," and the heat source control units 202, 302, 402, and 502 will also be referred to as the "child unit control units 202, 302, 402, and 502." The parent unit control unit 102 and the child unit control units 202, 302, 402, and 502 cooperate with each other to control the heating system 2. For example, the parent unit control unit 102 transmits instructions related to the operation of the heat source units 200, 300, 400, and 500 (e.g., an instruction to start a first heating operation) to the child unit control units 202, 302, 402, and 502. The slave unit control units 202, 302, 402, and 502 transmit information relating to the heat source units 200, 300, 400, and 500 that they control (for example, the temperature detected by the primary return thermistor 48) to the master unit control unit .

[0034] The heating system 2 further includes a remote control 10 capable of communicating with the parent unit control unit 102. The remote control 10 is operated by a user. The user can operate the remote control 10 to switch the power of the heating system 2 on and off and to perform various settings related to the heating system 2. For example, the user can set the heating target temperature (i.e., the temperature of the heat medium flowing in the heating circuit 6) of the heating terminals 8a, 8b, 8c via the remote control 10.

[0035] The parent device control unit 102 is configured to be able to communicate with a secondary forward thermistor 52 provided in the secondary forward flow path 16. The secondary forward thermistor 52 detects the temperature of the heat medium flowing in the secondary forward flow path 16 and transmits the detected temperature to the parent device control unit 102.

[0036] The master unit control unit 102 stores the heating signal most recently transmitted to the master unit control unit 102 (i.e., the heating signal most recently output by the thermostat 26a). The master unit control unit 102 also acquires and stores the heating signal most recently transmitted to the slave unit control units 202, 302 (i.e., the heating signal most recently output by the thermostats 26b, 26c) through communication with the slave unit control units 202, 302. This allows the master unit control unit 102 to know the heating signal most recently output by the thermostats 26a, 26b, 26c. The heating signals most recently output by the thermostats 26a, 26b, 26c indicate whether heating is being performed at the heating terminals 8a, 8b, 8c, respectively. If the heating signal most recently output by the thermostats 26a, 26b, 26c is a heating ON signal, heating is performed at the heating terminals 8a, 8b, 8c corresponding to the thermostats 26a, 26b, 26c. If the heating signal most recently output by the thermostats 26a, 26b, 26c is a heating OFF signal, heating is not performed at the heating terminals 8a, 8b, 8c corresponding to the thermostats 26a, 26b, 26c.

[0037] If at least one of thermostats 26a, 26b, and 26c has recently output a heating ON signal, heating is being performed by at least one of heating terminals 8a, 8b, and 8c, and therefore at least one of heat source units 100, 200, 300, 400, and 500 should be caused to perform a first heating operation (see FIG. 3) in order to supply heated heat medium to heating terminals 8a, 8b, and 8c. Therefore, if at least one of thermostats 26a, 26b, and 26c has recently output a heating ON signal, parent unit control unit 102 causes at least one of heat source units 100, 200, 300, 400, and 500 to perform a first heating operation. FIG. 5 shows an example in which thermostat 26a outputs a heating ON signal, and accordingly heating terminal 8a performs heating and heat source units 400 and 500 perform a first heating operation.

[0038] When the first heating operation is performed in at least one of the heat source units 100, 200, 300, 400, and 500, the parent unit control unit 102 repeatedly executes the processing shown in Fig. 6. The processing shown in Fig. 6 is processing for determining whether or not a detection failure has occurred in the secondary forward thermistor 52 based on the detected temperature of the primary return thermistor 48 (also referred to as the primary return detected temperature T1) and the detected temperature of the secondary forward thermistor 52 (also referred to as the secondary forward detected temperature T2), and for switching the mode of output control of the burner 32 depending on the determination result.

[0039] In S2, the parent unit control unit 102 acquires the primary return detection temperature T1 of the heat source unit that is performing the first heating operation. In the example of Fig. 5, the parent unit control unit 102 communicates with the child unit control units 402, 502 of the heat source units 400, 500 that are performing the first heating operation, and acquires the primary return detection temperature T1 of the heat source units 400, 500. The parent unit control unit 102 also acquires the secondary forward detection temperature T2 from the secondary forward thermistor 52. After S2, the processing proceeds to S4.

[0040] In S4, the parent unit control unit 102 determines whether or not an abnormal value is included among the primary return detection temperatures T1 acquired in S2. In the example of FIG. 5, multiple primary return detection temperatures T1 (i.e., the primary return detection temperatures T1 in the heat source units 400 and the primary return detection temperatures T1 in the heat source units 500) are acquired. In this case, the parent unit control unit 102 determines whether or not the multiple primary return detection temperatures T1 include a temperature that is abnormally higher than the others (or an abnormally lower than the others). If an abnormal value is included among the acquired primary return detection temperatures T1 (if YES), the process proceeds to S6.

[0041] In S6, the parent machine control unit 102 excludes the abnormal value identified in S4 from the primary return detection temperatures T1 acquired in S2. In subsequent processing (processing from S8 to S18), the parent machine control unit 102 refers to the primary return detection temperatures T1 from which the abnormal values ​​have been excluded. Furthermore, the parent machine control unit 102 may determine that a detection failure has occurred in the primary return thermistor 48 that indicates the abnormal value identified in S4.

[0042] After S6, or when there are no outliers in the primary return detection temperature T1 obtained in S2 (i.e., when the result in S4 is NO), the process proceeds to S8. In S8, the host controller 102 determines whether the temperature obtained by adding a predetermined buffer temperature Tb (e.g., Tb = 10°C) to the secondary forward detection temperature T2 is greater than or equal to the primary return detection temperature T1. That is, the host controller 102 determines whether T2 + Tb ≥ T1. When there are multiple primary return detection temperatures T1, the host controller 102 determines whether T2 + Tb ≥ T1 holds for each of the multiple primary return detection temperatures T1. And when T2 + Tb ≥ T1 holds for each of the multiple primary return detection temperatures T1, the host controller 102 determines YES. When T2 + Tb ≥ T1 does not hold for at least one of the multiple primary return detection temperatures T1 (i.e., when T2 + Tb < T1 holds), the host controller 102 determines NO. In another example, the host controller 102 may determine YES when T2 + Tb ≥ T1 holds for at least one of the multiple primary return detection temperatures T1. The host controller 102 may also determine NO when T2 + Tb ≥ T1 does not hold for each of the multiple primary return detection temperatures T1 (i.e., when T2 + Tb < T1 holds).

[0043] If the determination in S8 is YES, the process proceeds to S10. In S10, the host controller 102 determines that there is no detection failure in the secondary forward thermistor 52. After S10, the process proceeds to S12.

[0044] In S12, the host controller 102 executes the first output control process shown in FIG. 7. Although details will be described later, the first output control process is a process of controlling the output of the burner 32 based on the secondary forward detection temperature T2. After S12, the process shown in FIG. 6 ends.

[0045] If it is determined as NO in S8, the process proceeds to S14. In S14, it is determined whether the state where T2 + Tb < T1 (that is, the state where it is determined as NO in S8) has continued for a predetermined time or more. If the state where T2 + Tb < T1 (that is, the state where it is determined as NO in S8) does not continue for a predetermined time or more (NO case), the process returns to S8. If the state where T2 + Tb < T1 (that is, the state where it is determined as NO in S8) continues for a predetermined time or more (YES case), the process proceeds to S16.

[0046] In S16, the host controller 102 determines that a detection failure has occurred in the secondary forward thermistor 52. After S16, the process proceeds to S18.

[0047] In S18, the host controller 102 executes the second output control process shown in FIG. 8. Although the details will be described later, the second output control process is a process of controlling the output of the burner 32 without being based on the secondary forward detection temperature T2. After S18, the process shown in FIG. 6 ends.

[0048] (Principle of determination of detection failure) In the secondary forward flow path 16 shown in FIG. 1, a high-temperature heat medium flows after being heated by the heat source units 100, 200, 300, 400, 500 and before being radiated by the heating terminals 8a, 8b, 8c. On the other hand, in the primary return flow path 14, a low-temperature heat medium flows after being radiated by the heating terminals 8a, 8b, 8c and before being heated by the heat source units 100, 200, 300, 400, 500. From this, it is normal for the secondary forward detection temperature T2 (that is, the detection temperature of the secondary forward thermistor 52) to be higher than the primary return detection temperature T1 (that is, the detection temperature of the primary return thermistor 48). That is, it is normal for T2≧T1. However, when a detection failure occurs in the secondary forward thermistor 52, the secondary forward detection temperature T2 becomes significantly lower than the actual temperature of the heat medium flowing in the secondary forward flow path 16, and the secondary forward detection temperature T2 may become lower than the primary return detection temperature T1 (that is, T2<T1). Based on the above, in this embodiment, when the state where T2+Tb<T1 continues for a predetermined time or more, it is determined that a detection failure has occurred in the secondary forward thermistor 52 (see S8, S14, S16 in FIG. 6). Note that the buffer temperature Tb may be set to 0, may be set to a value greater than 0, or may be set to a value less than 0.

[0049] (First Output Control Process; FIG. 7) The first output control process is executed in S12 of the process shown in FIG. 6.

[0050] In S32, the master unit control unit 102 determines whether or not the temperature obtained by subtracting the secondary forward detection temperature T2 (that is, the detection temperature of the secondary forward thermistor 52) from the secondary forward target temperature exceeds a predetermined first increase threshold value (for example, 5°C). The secondary forward target temperature here refers to the target temperature of the heat medium flowing in the secondary forward flow path 16. The secondary forward target temperature is specified from, for example, the heating target temperature set by the user via the remote controller 10. When the temperature obtained by subtracting the secondary forward detection temperature T2 from the secondary forward target temperature exceeds the first increase threshold value (in the case of YES), the process proceeds to S34.

[0051] In S34, the parent unit control unit 102 increases the output set value of the burner 32 in the heat source unit that is performing the first heating operation. In the example of Fig. 5, the parent unit control unit 102 transmits an instruction to the child unit control units 402, 502 to increase the output set value of the burner 32. The child unit control units 402, 502 increase the output set value of the burner 32 that they control in response to the instruction from the parent unit control unit 102. After S34, the processing returns to S32.

[0052] In S32, if the temperature obtained by subtracting the secondary forward detection temperature T2 from the secondary forward target temperature is equal to or lower than the first increase threshold (if NO), the process proceeds to S36. In S36, the parent machine control unit 102 determines whether the temperature obtained by subtracting the secondary forward detection temperature T2 from the secondary forward target temperature is below a predetermined first decrease threshold (for example, -5°C). If the temperature obtained by subtracting the secondary forward detection temperature T2 from the secondary forward target temperature is below the first decrease threshold (if YES), the process proceeds to S38.

[0053] In S38, the parent unit control unit 102 reduces the output setting value of the burner 32. In the example of Fig. 5, the parent unit control unit 102 transmits an instruction to the child unit control units 402, 502 to reduce the output setting value of the burner 32. The child unit control units 402, 502 reduce the output setting value of the burner 32 that they control in response to the instruction from the parent unit control unit 102. After S38, the processing returns to S36.

[0054] In S36, if the temperature obtained by subtracting the secondary forward detection temperature T2 from the secondary forward target temperature is equal to or higher than the first decrease threshold value (if NO), the processing shown in FIG. 7 ends.

[0055] According to the first output control process, when the secondary forward detection temperature T2 is significantly lower than the secondary forward target temperature (i.e., when YES is returned in S32), the output set value of the burner 32 is increased (see S34), so the amount of heat that the burner 32 gives to the heat medium increases, and the temperature of the heat medium flowing in the secondary forward flow path 16 rises. Also, according to the first output control process, when the secondary forward detection temperature T2 is significantly higher than the secondary forward target temperature (i.e., when YES is returned in S36), the output set value of the burner 32 is decreased (see S38), so the amount of heat that the burner 32 gives to the heat medium decreases, and the temperature of the heat medium flowing in the secondary forward flow path 16 drops. Therefore, according to the first output control process, the temperature of the heat medium flowing in the secondary forward flow path 16 can be maintained near the secondary forward target temperature.

[0056] (Second output control process; Figure 8) The second output control process is executed in S18 of the process shown in FIG.

[0057] In S52, the parent device control unit 102 determines whether the temperature obtained by subtracting the primary forward detection temperature T3 (i.e., the temperature detected by the primary forward thermistor 50) from the primary forward target temperature exceeds a predetermined second increase threshold (e.g., 5°C). The primary forward target temperature here refers to the target temperature of the heat medium flowing through the primary forward flow path 12. The primary forward target temperature is identified, for example, from the heating target temperature set by the user via the remote control 10. If the temperature obtained by subtracting the primary forward detection temperature T3 from the primary forward target temperature exceeds the second increase threshold (if YES), the process proceeds to S54.

[0058] In S54, the parent unit control unit 102 increases the output set value of the burner 32 in the heat source unit that is performing the first heating operation. In the example of Fig. 5, the parent unit control unit 102 transmits an instruction to the child unit control units 402, 502 to increase the output set value of the burner 32. The child unit control units 402, 502 increase the output set value of the burner 32 that they control in response to the instruction from the parent unit control unit 102. After S54, the processing returns to S52.

[0059] In S52, if the temperature obtained by subtracting the primary forward detection temperature T3 from the primary forward target temperature is equal to or lower than the second increase threshold (if NO), the process proceeds to S56. In S56, the parent machine control unit 102 determines whether the temperature obtained by subtracting the primary forward detection temperature T3 from the primary forward target temperature is below a predetermined second decrease threshold (for example, -5°C). If the temperature obtained by subtracting the primary forward detection temperature T3 from the primary forward target temperature is below the second decrease threshold (if YES), the process proceeds to S58.

[0060] In S58, the parent unit control unit 102 reduces the output setting value of the burner 32. In the example of Fig. 5, the parent unit control unit 102 transmits an instruction to the child unit control units 402, 502 to reduce the output setting value of the burner 32. The child unit control units 402, 502 reduce the output setting value of the burner 32 that they control in response to the instruction from the parent unit control unit 102. After S58, the processing returns to S56.

[0061] In S56, if the temperature obtained by subtracting the primary forward detection temperature T3 from the primary forward target temperature is equal to or higher than the second decrease threshold value (if NO), the processing shown in FIG. 8 ends.

[0062] According to the second output control process, when the primary forward detection temperature T3 is significantly lower than the primary forward target temperature (i.e., when YES is returned in S52), the output set value of the burner 32 is increased (see S54), so the amount of heat that the burner 32 gives to the heat medium increases, and the temperature of the heat medium flowing in the primary forward flow path 12 rises. Also, according to the second output control process, when the primary forward detection temperature T3 is significantly higher than the primary forward target temperature (i.e., when YES is returned in S56), the output set value of the burner 32 is decreased (see S58), so the amount of heat that the burner 32 gives to the heat medium decreases, and the temperature of the heat medium flowing in the primary forward flow path 12 drops. Therefore, according to the second output control process, the temperature of the heat medium flowing in the primary forward flow path 12 can be maintained near the primary forward target temperature.

[0063] Furthermore, according to the second output control process, the output of the burner 32 can be controlled without being based on the secondary forward detection temperature T2 (i.e., the temperature detected by the secondary forward thermistor 52). As a result, even if a detection failure occurs in the secondary forward thermistor 52, the output of the burner 32 can be controlled without being affected by this.

[0064] (Variation) The number of heat source machines included in the heating system 2 is not limited to five, and may be one, two, three, four, or six or more.

[0065] The number of heating terminals included in the heating system 2 is not limited to three, but may be one, two, or four or more.

[0066] (See FIG. 1) The heating system 2 may further include a temperature sensor provided in the primary return flow path 14 to detect the temperature of the heat medium flowing in the primary return flow path 14. In this example, in S2 of the process shown in FIG. 6, the parent unit control unit 102 may obtain the detected temperature of the temperature sensor provided in the primary return flow path 14 as the primary return detected temperature T1, instead of obtaining the detected temperature of the primary return thermistor 48 as the primary return detected temperature T1.

[0067] (See FIG. 1) The secondary forward thermistor 52 may be provided on the upstream side of the terminal flow paths 22a, 22b, 22c relative to the heating terminals 8a, 8b, 8c.

[0068] (See FIG. 2) The fluid mixer 20 may be arranged such that the axial direction of the mixer body 72 is along the horizontal direction. In that case, the fluid mixer 20 may not include the debris removal valve 76 and the air vent valve 74. Further, the mixer body 72 may have a shape other than a cylindrical shape (for example, a spherical shape, a conical shape). Also, the positional relationship among the primary inlet 78, the primary outlet 80, the secondary outlet 82, and the secondary inlet 84 may be different from that in the embodiment. For example, the primary inlet 78, the primary outlet 80, the secondary outlet 82, and the secondary inlet 84 may be arranged so as not to face each other. Alternatively, the primary inlet 78 and the primary outlet 80 may be arranged so as to face each other through the inside of the mixer body 72. The secondary outlet 82 and the secondary inlet 84 may be arranged so as to face each other through the inside of the mixer body 72.

[0069] (See FIG. 6) In S2 of the process shown in FIG. 6, even if there are a plurality of heat source machines executing the first heating operation, the host control unit 102 may acquire only one of the plurality of primary return detection temperatures T1 among the plurality of primary return detection temperatures T1 in the plurality of heat source machines. The host control unit 102 may execute the subsequent processes (processes from S4 to S18) based on one primary return detection temperature T1.

[0070] (See FIG. 6) In the process shown in FIG. 6, S14 may be skipped. That is, when T2 + Tb < T1 (that is, when it is determined as NO in S8), the host control unit 102 may immediately determine that a detection failure has occurred in the secondary forward thermistor 52.

[0071] (See FIG. 6) In S18 of the process shown in FIG. 6, instead of executing the second output control process (see FIG. 8), the host control unit 102 may cause the heat source machine executing the first heating operation to stop the first heating operation. Then, the host control unit 102 may notify the user via the remote controller 10 or the like that a detection failure has occurred in the secondary forward thermistor 52.

[0072] (See FIG. 1) The heating system 2 may further include an outside air temperature sensor that detects the outside air temperature (e.g., the air temperature outside the house in which the heating system 2 is installed). The parent unit control unit 102 may be configured to vary the output set value of the burner 32 based on the outside air temperature acquired from the outside air temperature sensor in the first output control process shown in FIG. 7 and / or the second output control process shown in FIG. 8. For example, when increasing the output of the burner 32 in S34 of the first output control process, the parent unit control unit 102 may be configured to increase the output set value of the burner 32 by two stages if the outside air temperature acquired from the outside air temperature sensor is low, and to increase the output set value of the burner 32 by one stage if the outside air temperature is high.

[0073] (See FIG. 1) The heating system 2 may include a terminal remote control (not shown) corresponding to the heating terminals 8a, 8b, and 8c instead of or in addition to the thermostats 26a, 26b, and 26c. A user may be able to instruct the heating terminals 8a, 8b, and 8c to start or stop heating via the terminal remote control.

[0074] 8, the parent unit control unit 102 may increase or decrease the output set value of the burner 32 based on the primary return detection temperature T1, instead of increasing or decreasing the output set value of the burner 32 based on the primary forward detection temperature T3. Specifically, in S52 of the second output control process, the parent unit control unit 102 may determine whether or not the temperature obtained by subtracting the primary return detection temperature T1 from the primary return target temperature (i.e., the target temperature of the heat medium flowing in the primary return flow path 14) has exceeded a second increase threshold. In S56 of the second output control process, the parent unit control unit 102 may determine whether or not the temperature obtained by subtracting the primary return detection temperature T1 from the primary return target temperature has fallen below a second decrease threshold.

[0075] (Correspondence) In the embodiment, the hot water supply circuit 4 is an example of a "hot water supply circuit". The heating circuit 6 is an example of a "heating circuit". The heating terminals 8a, 8b, and 8c are examples of "heating terminals". The heat source machines 100, 200, 300, 400, and 500 are examples of "heat source machines". The heat source control units 102, 202, 302, 402, and 502 are examples of "control units". The primary forward flow path 12 is an example of a "primary forward flow path". The primary return flow path 14 is an example of a "primary return flow path". The secondary forward flow path 16 is an example of a "secondary forward flow path". The secondary return flow path 18 is an example of a "secondary return flow path". The fluid mixer 20 is an example of a "fluid mixer". The primary return thermistor 48 is an example of a "primary return temperature sensor". The detected primary return temperature T1 is an example of the "detected temperature of the primary return temperature sensor". The secondary forward thermistor 52 is an example of a "secondary forward temperature sensor". The detected secondary forward temperature T2 is an example of the "detected temperature of the secondary forward temperature sensor". The state where T2 + Tb < T1 is synonymous with the state where T2 - T1 < -Tb and is an example of "a state where the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor is less than a predetermined temperature". The output of the burner 32 is an example of the "heating capacity of the heat source machine". The first output control process is an example of the "first process". The second output control process is an example of the "second process".

[0076] The technical elements described in this specification or the drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Also, the technologies exemplified in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of those objectives itself has technical utility.

Description of Reference Numerals

[0077] 2: heating system, 4: hot water supply circuit, 6: heating circuit, 8a, 8b, 8c: heating terminal, 10: remote control, 12: primary forward flow path, 14: primary return flow path, 16: secondary forward flow path, 18: secondary return flow path, 20: fluid mixer, 22a, 22b, 22c: terminal flow path, 24a, 24b, 24c: terminal pump, 26a, 26b, 26c: thermostat, 32: burner, 34: first heat exchanger, 36: primary return branch path, 38: primary forward branch path, 40: heat source pump, 42: bypass path, 44 : Second heat exchanger, 46: Three-way valve, 48: Primary return thermistor, 50: Primary forward thermistor, 52: Secondary forward thermistor, 62a, 62b, 62c: First signal line, 64a, 64b, 64c: Second signal line, 72: Mixer body, 74: Air vent valve, 76: Debris vent valve, 78: Primary inlet, 80: Primary outlet, 82: Secondary outlet, 84: Secondary inlet, 100, 200, 300, 400, 500: Heat source unit, 102: Main unit control unit, 202, 302, 402, 502: Sub-unit control unit

Claims

1. a heat source machine that heats a heat medium; a heating terminal that heats by heat radiation from the heat medium; A heating circuit including a primary forward flow path through which the heat medium is sent from the heat source device, a primary return flow path through which the heat medium is sent to the heat source device, a secondary forward flow path through which the heat medium is sent to the heating terminal, and a secondary return flow path through which the heat medium is sent from the heating terminal; a fluid mixer fluidly connecting the downstream end of the primary forward flow path, the upstream end of the primary return flow path, the upstream end of the secondary forward flow path, and the downstream end of the secondary return flow path; a primary return temperature sensor for detecting the temperature of the heat medium flowing in the primary return flow path; a secondary forward temperature sensor that detects the temperature of the heat medium flowing in the secondary forward flow path; a control unit, A heating system in which the control unit determines whether a detection failure has occurred in the secondary forward temperature sensor based on the detected temperature of the primary return temperature sensor and the detected temperature of the secondary forward temperature sensor.

2. A plurality of the heat source machines; a plurality of the primary return temperature sensors corresponding to the plurality of heat source machines, The heating system of claim 1, wherein the control unit determines whether a detection failure has occurred in the secondary forward temperature sensor based on the detected temperature of one of the plurality of primary return temperature sensors and the detected temperature of the secondary forward temperature sensor.

3. A plurality of the heat source machines; a plurality of the primary return temperature sensors corresponding to the plurality of heat source machines, The heating system of claim 1, wherein the control unit determines whether a detection failure has occurred in the secondary forward temperature sensor based on the detected temperatures of two or more of the multiple primary return temperature sensors and the detected temperature of the secondary forward temperature sensor.

4. The heating system of claim 1, wherein the control unit determines that a detection failure has occurred in the secondary forward temperature sensor when the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor is less than a predetermined temperature.

5. The heating system of claim 1, wherein the control unit determines that a detection failure has occurred in the secondary forward temperature sensor when the temperature difference obtained by subtracting the detected temperature of the primary return temperature sensor from the detected temperature of the secondary forward temperature sensor remains below a predetermined temperature for a predetermined period of time or more.

6. The control unit is capable of executing a first process of controlling the heating capacity of the heat source unit based on the detected temperature of the secondary feed temperature sensor, The heating system according to claim 1 , wherein the control unit does not execute the first process when it is determined that a detection failure has occurred in the secondary forward temperature sensor.

7. The control unit is further capable of executing a second process of controlling the heating capacity of the heat source unit without being based on the detected temperature of the secondary feed temperature sensor, The heating system according to claim 6 , wherein the control unit executes the second process when it is determined that a detection failure has occurred in the secondary forward temperature sensor.

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