Chapter 5. Error Codes and Troubleshooting
94 AquaTrans™ AT600 User’s Manual
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5.2.2.1 Fluid Problems (cont)
• The fluid sound speed must not vary excessively.
The AT600 will tolerate relatively large changes in the fluid sound speed, as may be caused by
variations in fluid composition and/or temperature. However, such changes must occur slowly. Rapid
fluctuations in the fluid sound speed, to a value that exceeds the limit programmed into the AT600,
will result in erratic or inaccurate flow rate readings. Refer to Chapter 3, Initial Setup and
Programming, and make sure that the appropriate sound speed limit is programmed into the meter.
5.2.2.2 Pipe Problems
Pipe-related problems may result either from a failure to observe the installation instructions, as described
in Chapter 2, Installation, or from improper programming of the meter. By far, the most common pipe
problems are the following:
• The collection of material at the transducer location(s).
Accumulated debris at the transducer location(s) will interfere with transmission of the ultrasound
signals. As a result, accurate flow rate measurements are not possible. Realignment of the flowcell or
transducers often cures such problems, and in some cases, transducers that protrude into the flow
stream may be used. Refer to Chapter 2, Installation, for more details on proper installation practices.
• Inaccurate pipe measurements.
The accuracy of the flow rate measurements is no better than the accuracy of the programmed pipe
dimensions. For a flowcell supplied by GE, the correct data will be included in the documentation.
For other flowcells, measure the pipe wall thickness and diameter with the same accuracy desired in
the flow rate readings. Also, check the pipe for dents, eccentricity, weld deformity, straightness and
other factors that may cause inaccurate readings. Refer to Chapter 3, Initial Setup, for instructions on
programming the pipe data.
In addition to the actual pipe dimensions, the path length (
P) and the axial dimension (L), based on
the actual transducer mounting locations, must be accurately programmed into the flow meter. For a
GE flowcell, this data will be included with the documentation for the system. If the transducers are
mounted onto an existing pipe, these dimensions must be precisely measured.
• The inside of the pipe or flowcell must be relatively clean.
Excessive buildup of scale, rust or debris will interfere with flow rate measurement. Generally, a thin
coating or a solid well-adhered build up on the pipe wall will not cause problems. Loose scale and
thick coatings (such as tar or oil) will interfere with ultrasound transmission and may result in
incorrect or unreliable measurements.
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