# US 11,306,927 B2 · Systems and methods for fault detection using smart valves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,927 B2 - Document ID: US11306927B2 - Status: Granted - Kind: B2 - Application number: 16/601,768 - Filed: 2019-10-15 - Published: 2020-02-27 - Granted: 2022-04-19 - Earliest claimed: 2013-12-17 - Assignees: Belimo Holding AG - Applicants: Belimo Holding AG - Inventors: Ian Robert Dempster; Benjamin Paul Erpelding; Thomas Bennett Hartman; Chelsey Ann MacNeill - Web page: https://patentgrep.com/patent/US11306927B2 ## CPC - F24F 11/38: Failure diagnosis - F24F 3/044: Systems in which all treatment is given in the central station, i.e. all-air systems - F24F 3/08: with separate supply and return lines for hot and cold heat-exchange fluids {i.e. so-called "4-conduit" system} - F24F 11/30: for purposes related to the operation of the system, e.g. for safety or monitoring - F24F 11/62: characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values - F24F 11/63: Electronic processing - F24F 11/83: by controlling the supply of heat-exchange fluids to heat-exchangers - F24F 11/84: using valves - F24H 3/08: by tubes - G01K 13/02: for measuring temperature of moving fluids or granular materials capable of flow - F24F 11/32: Responding to malfunctions or emergencies - F24F 11/56: Remote control - F24F 2110/10: Temperature - F24F 2140/20: Heat-exchange fluid temperature - G01K 13/024: of moving gases - G01K 13/026: {of moving liquids} - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - F24H: FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL (steam generation F22) - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) ## Abstract A fault detection system for detecting a flow restriction in an air handler is provided. The system includes a coil, air and liquid temperature sensors, a smart valve and a notification device. The coil is located in an air stream of the air handler. The air temperature sensors are located in the air stream, one sensor determining an air temperature of air upstream of the coil and another determines an air temperature downstream of the coil. The liquid temperature sensors determine a liquid temperature entering the coil and exiting the coil. The smart valve includes a controller in communication with the liquid temperature sensors and at least one of the air temperature sensors that uses the measured air temperature downstream of the coil and a valve actuator position to determine whether the coil is operating at a reduced capacity. The notification device communicates with the controller of the smart valve. ## Claims ### Claim 1 A fault detection system for detecting a flow restriction in an air handler unit, the fault detection system comprising: a coil located in an air duct of the air handler unit, the coil configured to operate as a conduit for process fluid in the air duct; air temperature sensors located in an air duct of the air handler unit, one temperature sensor located to determine an air temperature of air present in the air duct upstream of the coil and another temperature sensor located to determine an air temperature of air present in the air duct downstream of the coil; liquid temperature sensors located to determine a liquid temperature entering the coil and to determine a liquid temperature exiting the coil; a smart valve having a controller in communication with the liquid temperature sensors and at least one of the air temperature sensors, the controller operable to use the air temperature downstream of the coil and a valve actuator position to determine whether the coil is operating at a reduced capacity; and a notification device in communication with the controller of the smart valve. ### Claim 2 (depends on 1) The fault detection system of claim 1, wherein the controller is configured to modulate the valve actuator position to minimize an energy loss of the air handler unit until rectification of the reduced capacity. ### Claim 3 (depends on 1) The fault detection system of claim 1, wherein the controller is configured to modulate the valve actuator position to produce an overflow of liquid supplied to the coil. ### Claim 4 (depends on 3) The fault detection system of claim 3, wherein the overflow of liquid supplied to the coil mitigates a performance loss of the air handler unit for a designated period of time. ### Claim 5 (depends on 4) The fault detection system of claim 4, wherein the designated period of time is an amount of time for the rectification of the reduced capacity. ### Claim 6 (depends on 1) The fault detection system of claim 1, wherein the controller of the smart valve is configured, upon determining the reduced capacity, to send a message to the notification device. ### Claim 7 A fault detection system for detecting a flow restriction in an air handler unit, the fault detection system comprising: a coil located in an air duct of the air handler unit, the coil configured to operate as a conduit for process fluid in the air duct; an air temperature sensor located in an air duct of the air handler unit to determine an air temperature downstream of the coil; and a smart valve having a controller in communication with the air temperature sensor, the controller operable to use the air temperature downstream of the coil and a valve actuator position to determine whether the coil is operating at a reduced capacity, and to modulate the valve actuator position to minimize an energy loss of the air handler unit until rectification of the reduced capacity. ### Claim 8 A fault detection system for detecting a flow restriction in an air handler unit, the fault detection system comprising: a coil located in an air duct of the air handler unit, the coil configured to operate as a conduit for process fluid in the air duct; an air temperature sensor located in an air duct of the air handler unit to determine an air temperature downstream of the coil; a smart valve having a controller in communication with the air temperature sensor, the controller operable to use the air temperature downstream of the coil and a valve actuator position to determine whether the coil is operating at a reduced capacity; and a notification device in communication with the controller of the smart valve, whereby upon determining the reduced capacity, the controller of the smart valve sends a message to the notification device.