ADS Environmental Services IETG FlowHawk QR 775012 A4 - Manual (Page 341)

Maintenance and Troubleshooting 8-57
Problem Velocity data seems erratic or exhibits poor quality.
Possible
Causes
Sensor transmit/receive surfaces may be dirty.
Sensor may be close to extending out of the flow.
Designated value for the maximum velocity parameter
may be too high, creating too broad of a range.
Sensor may be faulty.
Processor board may be faulty.
Possible
Solutions
Clean the sensor transmit/receive surfaces.
Verify whether the flow depth exceeds the sensor
deadband at the same time and under the same
conditions as the erratic data. Rotate the sensor further
toward the center of the pipe if possible.
Reduce the maximum velocity in the device parameters
to narrow the range.
Check the sensor connections.
Check the velocity parameters.
Contact your regional IETG representative.
Replace the sensor.
Replace the monitor if defective.
Problem Velocity readings are abnormally high.
Possible
Causes
Sensor’s transmit/receive surfaces may be covered with
silt or other debris.
Sensor may be extending out of the flow.
Flow may be reversed or slower than 0.15 meters per
second (0.5 fps).
Possible
Solution
Check the site conditions, and relocate the sensor if
necessary.