Dwyer TDFT Series Thermal Dispersion Flow Transmitter are sensors with an electrical contact output at a specific flow rate. Dwyer models provide a complete system for leak detection and feature a selectable NO or NC operation. Applications include chillers, hot water heaters, and liquid transfer systems. The Model TDFT Thermal Dispersion Flow Transmitter has continuous frequency output. It fits applications with pipe sizes from 1/2″ to 2″ (12.7 to 50 mm) and features 316L stainless steel housing for use in harsh environments.

Dwyer has invested in state-of-the-art research and development facilities for best-in-class product testing and verification. Dwyer has a long history of innovation in designing and manufacturing our own measurement sensors that provide superior product performance.

Flow includes Flow Transmitters, Flow Sensors, Flowmeters, Sight Flow Indicators, and Water Meters. Mass Flowmeters, Controllers, Flow Indicators, and Controllers are ideal for the measurement of flow rates. Flow Switches come as paddle, thermal, piezo, and shuttle/piston. Flow Switch Sensors with an electrical contact output at a specific flow rate have different types of switches, which are a paddle, thermal, piezo, and shuttle/piston.

Dwyer TDFT Series Features

  • Flow measurement in low flow applications
  • Continuous frequency signal from measured flow velocity
  • Low pressure drop
  • No moving parts


  • Chiller systems
  • Boiler systems
  • Liquid transfer systems
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Dwyer TDFT Series Specification

Service Compatible water-based fluids.
Wetted Materials 316L SS.
Range 1-3 ft/s (0.05-0.7 m/s).
Repeatability ±10% at 68°F (20°C).
Temperature Limits Ambient: -4 to 158°F (-20 to 70°C), Process: 14 to 140°F (-10 to 60°C), Storage: -40 to 158°F (-40 to 70°C).
Pressure Limit 362 psi (25 bar).
Response Time 1 to 10 seconds.
Power Requirements 24 VDC.
Current Consumption <50 mA.
Electrical Rating 80 mA.
Output Frequency 5 to 74 Hz.
Electrical Connections 1 x M12.
Process Connection ½” NPT.
Enclosure Rating IP67.
Housing Material 316L SS.
Mounting Orientations Horizontal or vertical.
Weight 0.274 lb (124.5 g).
Agency Approvals CE.

Download Data Sheet: Model TDFT Thermal Dispersion Flow Transmitter

Ref: dwyer-inst.com