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  • Air and non-conductive gases
  • ±1% FS accuracy
  • Operating temp: 0 to 150°F
  • 10 psig over pressure
  • 4 to 20 mA, 2-wire output
  • 3/16in OD fitting for 1/4in ID tubing pressure connection


The Dwyer 668 Differential Pressure Transmitter is capable of measuring low pressures with a ±1% accuracy. It is ideally suited for proper building pressurization and air flow control. Transmitters can withstand up to 10 psig overpressure with no damage to the unit. Variable capacitance sensor design provides excellent sensitivity and long-term stability. Compact, lightweight design makes installation simple and easy. Units also feature reverse polarity protection.

Applications for the 668 include:

  • Variable air volume systems
  • HVAC
  • Building management