# US 2024/0200831 A1 · Method and apparatus for determining fault of heating apparatus, and electric water heater > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0200831 A1 - Document ID: US20240200831A1 - Status: Published application - Kind: A1 - Application number: 18/576,292 - Filed: 2022-03-15 - Published: 2024-06-20 - Earliest claimed: 2021-06-16 - Applicants: A. O. Smith (China) Water Heater Co., Ltd. - Inventors: Xing LIU; Ran TAO; Qiang HUANG - Web page: https://patentgrep.com/patent/US20240200831A1 ## CPC - F24H 15/124: Preventing or detecting electric faults, e.g. electric leakage - F24H 9/20: Arrangement or mounting of control or safety devices - F24H 15/104: Inspection; Diagnosis; Trial operation - F24H 15/414: using electronic processing, e.g. computer-based - F24H: FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL (steam generation F22) ## Abstract Embodiments of this disclosure provide a method and apparatus for determining a fault of a heating device and an electric water heater. When the heating device includes at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit include a heating element and a switch controlling the heating element, the method includes: acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and acquiring a variation value of the main circuit current value caused by turning on/off the switch, and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value. With the embodiments of this disclosure, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability. ## Claims ### Claim 1 A method for determining a fault of a heating device, characterized in that when the heating device comprises at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit comprises a heating element and a switch controlling the heating element, the method comprises: acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and acquiring a variation value of the main circuit current value caused by turning on/off the switch and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value. ### Claim 2 (depends on 1) The method according to claim 1, characterized in that the first current value is a preset current value, the preset current value being set based on a total current of all N heating elements in an operation state on a same phase line, or being set based on a total current of N−1 heating elements in the N heating elements; where, N is an integer not less than 2. ### Claim 3 (depends on 1) The method according to claim 1, characterized in that the method further comprises: updating an acquired main circuit current value to the first current value when it is determined that no heating unit occurs a fault. ### Claim 4 (depends on 1) The method according to claim 1, characterized in that the acquiring a variation value of the main circuit current value caused by turning on/off the switch comprises: sequentially selecting a heating element in operation, and in a case where operating states of other heating elements are not changed, detecting a first main circuit current value when the heating element is in operation and a second main circuit current value after the heating element stops operating. ### Claim 5 (depends on 4) The method according to claim 4, characterized in that after a switch controlling operation of the heating element is turned on, the first main circuit current value is detected, and after the switch controlling the operation of the heating element is turned off, the second main circuit current value is detected. ### Claim 6 (depends on 1) The method according to claim 1, characterized in that the method further comprises: controlling the heating element where the fault occurs to stop operating; and starting a heating element that is not in operation and not occurring a fault, and is on the same phase line as the heating element where the fault occurs. ### Claim 7 (depends on 1) The method according to claim 1, characterized in that the method further comprises: determining that a fault occurs in a switch in at least one heating unit when the main circuit current value is not less than a second current value. ### Claim 8 (depends on 7) The method according to claim 7, characterized in that the method further comprises: disconnecting a power switch of the heating device after it is determined that a fault occurs in the switch in the at least one heating unit. ### Claim 9 (depends on 1) The method according to claim 1, characterized in that the method further comprises: calculating a cumulative operating time of the at least two heating units in an operating state parallelly arranged on the branches of a same phase line according to the main circuit current value; and adjusting starting sequences of the heating elements according to the cumulative operating time. ### Claim 10 (depends on 9) The method according to claim 9, characterized in that the adjusting starting sequences of the heating elements according to the cumulative operating time comprises: dynamically adjusting starting priorities of the heating elements according to the cumulative operating time; wherein starting priorities of heating elements with long cumulative operating time is low, and starting priorities of heating elements with short cumulative operating time is high; and starting the heating elements according to the starting priorities. ### Claim 11 A method for determining a fault of a heating device, characterized in that when an operating current of the heating device is a three phase supply current, each phase line of three phase lines comprises at least two heating units in an operating state parallelly arranged on branches and the heating unit comprises a heating element and a switch controlling the heating element, the method comprises: acquiring a main circuit current value of each phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit in a phase line where the main circuit is located when the main circuit current value is not greater than a first current value; and acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs, and determining that a fault occurs in a branch where a heating element controlled by the switch is located when the variation value of the main circuit current value is not greater than a preset variation value. ### Claim 12 (depends on 11) The method according to claim 11, characterized in that the acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs comprises: sequentially selecting a heating element in operation in the phase line where a fault occurs in heating elements, and detecting a first main circuit current value when the heating element is in operation and a second main circuit current value after the heating element stops operating, in a case where operating states of other heating elements unchanged. ### Claim 13 (depends on 12) The method according to claim 12, characterized in that after the switch controlling the operation of the heating element is turned on, the first main circuit current value is detected, and after the switch controlling the operation of the heating element is turned off, the second main circuit current value is detected. ### Claim 14 (depends on 11) The method according to claim 11, characterized in that the first current value is a preset current value, the preset current value being set based on a total current of all N heating elements in an operation state on a same phase line, or being set based on a total current of N−1 heating elements in the N heating elements; where, N is not less than 2. ### Claim 15 (depends on 11) The method according to claim 11, characterized in that the method further comprises: when it is determined that no heating element occurs a fault, updating an acquired main circuit current value of each phase line to the first current value to which each phase line corresponds. ### Claim 16 (depends on 1) An apparatus for determining a fault of a heating device, comprising a processor, the processor being configured to execute the method for determining a fault of a heating device as claimed in claim 1. ### Claim 17 (depends on 16) An electric water heater, characterized in that the electric water heater comprises: a heating device comprising at least two heating units parallelly arranged on branches of a same phase line, the heating unit comprising a heating element and a switch controlling operation of the heating element; the apparatus for determining a fault of the heating device as claimed in claim 16; and a waterway assembly, the heating elements being used to heat water in the waterway assembly. ### Claim 18 (depends on 17) The electric water heater according to claim 17, characterized in that an operating current of the heating device is a three phase power supply current, each of the three phase lines comprises at least two heating units parallelly arranged in a branch, and the heating elements on the three phase lines are connected in a star or triangle shape. ### Claim 19 (depends on 17) The electric water heater according to claim 17, characterized in that the electric water heater comprises at least two cascaded sub-electric water heaters, each sub-electric water heater being provided with a waterway assembly and at least one heating unit, and at least one heating unit of each sub-electric water heater being connected in parallel on a same phase line. ### Claim 20 (depends on 17) The electric water heater according to claim 17, characterized in that, the apparatus for determining a fault of a heating device further comprises a current transformer for acquiring a main circuit current value, the heating element is a heating rod, and the waterway assembly comprises an inner tank for water storage.