Hach-Lange 5740 sc - Manual (Page 23)

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Section 5 Maintenance
DANGER
Only qualified personnel should conduct the tasks described in this section of the
manual.
5.1 Maintenance Schedule
5.2 Cleaning the Sensor
Clean the exterior of the sensor with a stream of water. If debris remains, wipe with a soft,
wet cloth.
5.2.1 Cleaning the Galvanic Sensor
Clean the sensor membrane before each calibration to ensure best results. Clean and
calibrate monthly or until operating experience determines appropriate intervals.
Using a soft wet cloth and mild soap solution, remove all debris from the membrane
surface. Rinse thoroughly with distilled water.
Note: While cleaning the sensor membrane, be careful not to puncture it.
5.3 Preventing the Sensor Membrane from Drying Out
When the sensor is removed from the process solution, its membrane immediately begins
drying out. After more than 24 hours, the electrolyte behind the membrane may become
depleted due to evaporation. If the sensor is returned to operation after this has occurred,
measurement readings may be inaccurate.
Membrane dry-out and electrolyte evaporation can be avoided by temporarily placing the
sensor in a container of clean drinking water until it can be put back into operation.
Maintenance Task 90 days 120 days 365 days
Clean the sensor 1
1 Cleaning frequency is application dependent. More or less frequent cleaning will be appropriate in some applications.
x
Inspect sensor for damage x
Replace sensor x
Replace sensor O-rings x
Calibrate Sensor (as required by regulatory agency)
Per the schedule mandated by your regulatory
agency.