as necessary. See Section 5 for instructions on
performing a 1-point calibration.
4.5 Sensor Maintenance – Trace DO System Troubleshooting
If the sensor is not providing reasonable signals to the Remote Display, check the following:
Verify that process is flowing through the sample chamber. If flow is blocked, the sensor will
consume the available oxygen in the sample chamber and display a 0 ppb dissolved oxygen
measurement.
Inspect the integrity of the sensor membrane. If the membrane is torn or punctured, replace it
with a new membrane cap and fresh electrolyte.
Inspect the sensor cable for damage. Any cuts or kinks in the outer jacket may damage signal
connections.
Inspect the terminal block connections to be sure the wires are not corroded or loose.
Make sure all sensor wires are connected properly to the AV38 Remote Display terminal block.
Immerse the sensor in a solution of known dissolved oxygen value and check the displayed
measurement.
Verify that the AV38 Remote Display electronics are working correctly by connecting it to
another sensor if available.
Note: Any new sensor that has been in storage for more than a few days should be
soaked in clean water for at least 30 minutes before reviewing measurement
performance.
Note: The membrane of any DO sensor in storage must be kept moist at all times. The
protective cap should be filled with clean water and placed securely over the sensor
head.
Thermo Scientific AquaSensors
™
AquaTrace
™
Trace DO System User Guide
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