Dwyer Instruments TDFS series thermal flow switch uses impulse thermal dispersion measurement to indicate the flow rate. Thermal dispersion measurements offer benefits over traditional flow meters with no paddles or vanes to wear or break. The TDFS features set point flow rates that are field adjustable. It provides NO and NC NPN outputs and two LEDs, for high and low set point indication.Long-term reliability . High life expectancy. Not affected by empty pipe detection . Field adjustable set points. LED status indicatorsMedia Monitored = FluidDevice Type = Flow SwitchMinimum Flow Rate = 0.15 m\/sMaximum Flow Rate = 3 m\/sSupply Voltage = 9 - 24 V dcPipe Diameter Range = 1\/2 inConnection Type = 1\/2 NPT MaleMaximum Pressure = 34.47barMaterial = Stainless SteelMinimum Media Temperature = -15 °C