The EUP Ultra-Low Pressure Transmitter can be used to measure positive, negative or differential pressure in the ranges of 0.1”wc to 0.4”wc and 25 Pa to 100 Pa. The pressure sensor technology is based on thermal flow measurement of gas through a micro-flow channel within the sensor chip, which results in superior sensitivity for ultra low pressures. The extremely low gas flow through the sensor ensures high immunity to dust contamination, humidity and long tubing. The device features field selectable current or voltage output signal types and can be set for unidirectional or bidirectional pressure measurements for the most flexible application. Typical HVAC applications include monitoring of filter differential pressure or clean room pressure. The output signal is factory calibrated and temperature compensated for highest start-up accuracy and trouble-free operation. A Polycarbonate enclosure with a hinged and gasketed cover is provided for ease of installation.