Low Differential Pressure Transmitter AI178A
Pressure Medium: Air/Gas
Sensor Type: Differential
Supply Voltage: 5V
Output Signal: 4-20 mA
Pressure Range: Under 4” H2O
Kind: Packaged Transducer

Model 178A Series are low-range differential pressure transmitters. Each unit features a 3 1/2 digit LCD to show the pressure, also a push button switch (inside) for zero pressure calibration. 

All new inquiries for these parts should contact Alpha Instruments directly via their  Contact Us page or at This email address is being protected from spambots. You need JavaScript enabled to view it.. You may also contact us with any questions and we can forward your inquiry accordingly.

The AI178A Series has a SS304 front panel and an IP65/NEMA 4 rated aluminum die casting enclosure, good for many indoor and outdoor applications. The pressure ranges from 0.1" WC to 100" WC, uni-directional or bi-directional. The output is 2-wire 4-20 mA, fully protected against short circuiting and incorrect wiring. All units are temperature-compensated with available accuracies of 0.8%, 0.4% and 0.25% FS. The patented stainless steel diaphragm sensor provides good corrosion resistance, excellent repeatability and long term stability.


  • 3 1/2 digit LDC display
  • Up to 15 PSI overpressure
  • Incorrect wiring protection
  • Rugged aluminum housing rated NEMA 4/IP65
  • RoHS Compliance
  • Pressure ranges as low as 0 - 0.1"WC
  • Temperature-compensated
  • Uni-directonal or bi-directional

Typical Uses

  • HVAC air pressure and VAV pressure sensor
  • Cleanroom pressure and fume hood airflow control
  • Duct static pressure measurement
  • Draft control
  • Furnace airflow control
  • Isolation rooms