ADS Environmental Services FlowAlert QR 775011 A2 - Manual (Page 28)

Pressure Depth Sensor and Float Switch Installation 3-5
 Pipe Shape Taking the appropriate measurements that
precisely reflect the exact pipe shape is essential to obtaining
accurate flow calculations. Therefore, irregular-shaped pipes
will require additional measurements if accurate flow
measurements are essential. Refer to the Profile User’s Guide
(#950015**) for more information.
 Manhole Depth Measure the distance from the top of the
manhole to the bottom of the manhole invert. This
measurement may be required to determine the elevation for the
float switch. Distances beyond 35 will require extension cables
for the sensor. Manhole depth and expected surcharge levels
also determine the PSI of the pressure depth sensor to install.
 Manhole Obstructions Carefully inspect the manhole for
possible obstructions that may pose a hazard to the hanging
float switch or prevent the float from freely changing position
when the flow is rising or receding. Obstacles or obstructions,
such as ledges, can create an opportunity for the float to
become lodged, producing an inaccurate representation of the
float switch state.