An anti-icing system comprising: an aircraft structure that includes a cavity having an exterior surface subject to ice accretion and a bleed source configured to provide a fluid to the cavity via a duct , wherein the duct delivers fluid to the aircraft structure; multiple temperature sensors , disposed at the aircraft structure, each temperature sensor configured to detect a temperature associated with an aircraft structure location; a controller in communication with the temperature sensors , the controller programmed to compare outputs of the temperature sensors and determine a temperature sensor fault condition ; at least two valves arranged within the duct and configured to regulate fluid to the aircraft structure; wherein the temperature sensors are disposed at the aircraft structure downstream from the duct; and wherein the controller is configured to receive feedback from the multiple temperature sensors to determine at least one of a de-iced condition and a faulty valve condition, wherein the at least two valves comprise first and second valves , wherein the controller is programmed to command one of the first and second valves to a full open position and regulate the flow of the fluid with the other of the first and second valves in a first condition, and to command the other of the first and second valves to the full open position and regulate the flow of the fluid with the one of the first and second valves in a second condition; and if one of the first and second valves is determined to be faulty by the controller , a valve control mode is configured to lock the faulty valve open. an aircraft structure that includes a cavity having an exterior surface subject to ice accretion and a bleed source configured to provide a fluid to the cavity via a duct , wherein the duct delivers fluid to the aircraft structure; multiple temperature sensors , disposed at the aircraft structure, each temperature sensor configured to detect a temperature associated with an aircraft structure location; a controller in communication with the temperature sensors , the controller programmed to compare outputs of the temperature sensors and determine a temperature sensor fault condition ; at least two valves arranged within the duct and configured to regulate fluid to the aircraft structure; wherein the temperature sensors are disposed at the aircraft structure downstream from the duct; and wherein the controller is configured to receive feedback from the multiple temperature sensors to determine at least one of a de-iced condition and a faulty valve condition, wherein the at least two valves comprise first and second valves , wherein the controller is programmed to command one of the first and second valves to a full open position and regulate the flow of the fluid with the other of the first and second valves in a first condition, and to command the other of the first and second valves to the full open position and regulate the flow of the fluid with the one of the first and second valves in a second condition; and if one of the first and second valves is determined to be faulty by the controller , a valve control mode is configured to lock the faulty valve open. <EOS>