All units come with a 4 ½” magnehelic meter for pressure readout—optional digital display must be ordered at the time of purchase.

Normal ranges available are:
  • 0 – 3 inches of water
  • 0 – 5 inches of water
  • 0 – 30 inches of water
  • 0 – 50 inches of water
  • 0 – 80 inches of water
  • 0 – 3 psi *
  • 0 – 5 psi * or 0 – 120” of water (Maximum range)
  • Other ranges available upon request.
Available also in mbar (0-300 mbar maximum)
  • Killipascal ( 0 – 30 kPa max)
  • Ounces per square inch (0-80 oz per sq in)
  • Millimeters of water column (0-125 mm w.c.)
  • Centimeters of water column (0-350 cm w.c.)

*If ordering unit with a digital display option, please note cannot read in psi.

How to help you choose a range:
  • Your target operating pressure should be in the middle of the range. Note operating a unit below 10% of full scale will lose some precision.
  • One psi = 27.68” of water
  • There are too many variables on a tubing line including what type of material, line speed, etc. for us to pick a range for you. High ranges like 0-3 psi and 0-5 psi are used most often making automotive tubing while the lower ranges of 0-5” of water, 0-15” of water and 0-30” of water are the most popular for medical tubing.
  • All MicroAir I and MicroAir II units can be easily range changed free within 30 days of purchase or with a kit purchased from OLC. The MicroAir IV unit can be ranged change if needed at our factory for a fee.

*Digital Display are accurate to +/-.1% of full scale below 60” of water (.01” of water) and +/-.3% of full scale above 3 psi (.03 psi). One decimal place (00.1) on units with a maximum range above 10” of water. Two decimal places (0.01) are available below 10” of water range.

“Let the tube talk to you. Less is best” – Bob Bessemer of Conair

All MicroAir units do not need to be calibrated as the unit is factory set before shipping.

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