A fluid flow system for directing a fluid toward a use device comprising: a plurality of resistance temperature detectors (RTDs) ; a heating circuit in electrical communication with the plurality of RTDs and capable of applying electrical power to the RTDs ; a measurement circuit in communication with the plurality of RTDs ; a controller in communication with the heating circuit and the measurement circuit and capable of operating each of the plurality of RTDs in a heating mode via the heating circuit and a measurement mode via the measurement circuit , the controller being configured to: operate each of the one or more of the plurality of RTDs in the heating mode of operation in order to maintain each of the one or more RTDs at a different elevated characterization temperature to induce a deposit from the process fluid to form on at least one of the one or more RTDs , the characterization temperature of one RTD being different from the characterization temperature of all other RTDs , at least one of the characterization temperatures being higher than a typical operating temperature of the use device ; for each of the one or more RTDs , periodically switch the RTD between the heating mode and the measurement mode in order to measure the temperature of the RTD , observe changes in the thermal behavior of the RTD in one or both of the heating mode and the measurement mode, and characterize a level of deposit from the process fluid onto the RTD based on the observed changes; determine a temperature-dependent deposition profile based on the characterized level of deposit of each of the one or more RTDs ; and determine if a deposit condition exists for the use device based on the deposition profile. a plurality of resistance temperature detectors (RTDs) ; a heating circuit in electrical communication with the plurality of RTDs and capable of applying electrical power to the RTDs ; a measurement circuit in communication with the plurality of RTDs ; a controller in communication with the heating circuit and the measurement circuit and capable of operating each of the plurality of RTDs in a heating mode via the heating circuit and a measurement mode via the measurement circuit , the controller being configured to: operate each of the one or more of the plurality of RTDs in the heating mode of operation in order to maintain each of the one or more RTDs at a different elevated characterization temperature to induce a deposit from the process fluid to form on at least one of the one or more RTDs , the characterization temperature of one RTD being different from the characterization temperature of all other RTDs , at least one of the characterization temperatures being higher than a typical operating temperature of the use device ; for each of the one or more RTDs , periodically switch the RTD between the heating mode and the measurement mode in order to measure the temperature of the RTD , observe changes in the thermal behavior of the RTD in one or both of the heating mode and the measurement mode, and characterize a level of deposit from the process fluid onto the RTD based on the observed changes; periodically switch the RTD between the heating mode and the measurement mode in order to measure the temperature of the RTD , observe changes in the thermal behavior of the RTD in one or both of the heating mode and the measurement mode, and characterize a level of deposit from the process fluid onto the RTD based on the observed changes; determine a temperature-dependent deposition profile based on the characterized level of deposit of each of the one or more RTDs ; and determine if a deposit condition exists for the use device based on the deposition profile. <EOS>