Manometer Accessories

A static pressure probe reads only the static (non-moving) pressure component in a duct, typically through small holes perpendicular to airflow. A Pitot tube reads total pressure at its tip facing into the airflow and static pressure through side ports simultaneously, and the manometer calculates the difference (velocity pressure) to derive air velocity — the two serve different measurement purposes and aren't interchangeable.

Tubing inner diameter affects response time and can affect reading accuracy if it doesn't seal properly onto the manometer's port barb. Undersized tubing may not seat fully and leak, while oversized tubing won't grip the barb — always match the original manufacturer's specified tubing ID, commonly 1/8 in or 3/16 in depending on the instrument.

Most manometers should be zeroed before each use session since ambient pressure and temperature drift can offset the reading, and this is typically a built-in function requiring no accessory. Full calibration against a certified pressure standard is usually done annually or per your quality system's documented interval, which does require a calibration kit or reference standard.

Physically, most Pitot tubes use standard tubing connections and will connect to most manometers, but accuracy depends on the Pitot tube's calibration coefficient matching what the manometer's airflow calculation assumes. For accurate velocity and flow readings, use a Pitot tube from the same manufacturer as the manometer, or confirm the coefficient is correctly set in the instrument.

Filter and grille probes need to be long enough to seat fully against the filter face or diffuser opening being tested while keeping the manometer's display readable and the tubing untangled — common lengths run 6 to 12 inches for filter probes. For duct insertion probes measuring at the duct centerline, length depends on duct depth, commonly 12 to 36 inches.