The LGF-PA66 is rated at ±0.2% — how much do field installation conditions affect actual accuracy?

The ±0.5% (DN50-100) figure is the reading accuracy of the LGF-PA66 under a wet-calibration condition with the installation requirements met. Real on-site accuracy is decided mainly by the flow profile: repeatability is 0.1%, so once the site conditions are right, long-term accuracy does not degrade by an order of magnitude.

Factors that hurt field accuracy, largest first:

• Short straight runs come first. If the upstream run is under 5D or the meter sits right behind an elbow, valve or reducer, the distorted velocity profile can push the error above 1%; where possible extend the upstream run to 10D or fit a flow conditioner.
• A partially filled tube and gas bubbles break the basic measuring premise — that is a wrong mounting location; relocate the meter rather than tolerating it.
• When conductivity is near the 5 µS/cm lower limit the signal margin is thin: choose the remote (split) version to shorten the signal cable and do a zero calibration under full-pipe, zero-flow conditions before startup.
• Poor earthing causes zero drift. The LGF-PA66 has an insulating body, so there is no pipe-wall corrosion issue, but the converter earthing terminal must still be reliably grounded.

A practical way to verify field accuracy is a portable ultrasonic comparison or a master-meter check in series; a deviation within ±0.5% indicates the installation is acceptable. Order the 0.2-class meter and install it per the manual, and the field accuracy will hold. For more information, please visit our product page or contact our technical team.