Maintenance, Maintenance -1, Nperiodic maintenance – Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 User Manual
Page 208: Caution, Nperiodic maintenance of the sensor, Ph sc isc do

<18. MAINTENANCE>
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IM 12A01A02-01E
5th Edition : Oct. 31, 2013-00
18. MAINTENANCE
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Periodic maintenance
The FLXA21 requires very little periodic maintenance, except to make sure the front window
is kept clean in order to permit a clear view of the display and allow proper operation of the
touchscreen. If the window becomes soiled, clean it using a soft damp cloth or soft tissue.
To deal with more stubborn stains, a neutral detergent may be used.
When you must open the front cover and/or glands, make sure that the seals are clean and
correctly fitted when the unit is re-assembled in order to maintain the housing’s weatherproof
integrity against water and water vapor.
The pH measurement uses high impedance sensors and may otherwise be prone to problems
caused by exposure of the circuitry to condensation.
CAUTION
Never use harsh chemicals or solvents. In the event that the window does become heavily
stained or scratched, refer to the parts list for replacement part numbers.
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Battery
The FLXA21 has a logbook feature that uses a clock to provide the timings. The instrument
contains a lithium cell (battery) to continue the clock function while the power is turned off.
Although the cell has an expected working life of 10 years, this is not guaranteed. When this cell
needs replacing, contact your nearest Yokogawa service center.
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Periodic maintenance of the sensor
Please follow the manual of each sensor about the maintenance of the sensor.
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Predictive maintenance
The FLXA21 has a unique prediction function (wellness check).
By making settings concerning the sensor wellness check, you can grap the condition of the
sensor in the gauge display in the Detail screen and carry out predictive maintenance.
See section 4.2.7, 7.1.7, 10.1.7, 13.2.7, or 16.2.7, Sensor diag. settings.
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