Maintenance And Troubleshooting; Sensor Maintenance - Dissolved Oxygen; Cleaning The Sensor Cap; Sensor Cap Replacement - VWR DO220 Bedienungsanleitung

to become completely saturated and to allow the temperature and
dissolved oxygen sensors to stabilize.
3. Press CAL to enter the calibration routine. You can press Mode at
anytime to cancel the calibration.
4. The display prompts for the local, true barometric pressure in mbar
(millibars). Use the Up and Down Arrow keys to increase or decrease
the barometric pressure value, then press Enter.
5. The display will show the current dissolved oxygen measurement on
the main display and the calibration value in the lower right corner.
Wait for the DO measurement to stabilize, then press Enter.
6. The display prompts for the approximate salinity of the water to be
analyzed. Use the Up and Down Arrow keys to increase or decrease
the salinity compensation value to the salinity value of your sample
(between 0 to 40 parts per thousand [ppt]). When the correct salinity
displays, press Enter.
7. The unit holds calibration for several months, even when powered
off and on.
M a i n t e n a n c e a n d T r o u b l e s h o o t i n g

Sensor Maintenance - Dissolved Oxygen

Cleaning the Sensor Cap

The Sensor Cap should be kept clean since some types of fouling can
consume or produce oxygen or block the water sample from reaching the
sensor which could affect the dissolved oxygen measurements.
To clean the Sensor Cap, gently wipe away any fouling with a lens
cleaning tissue that has been moistened with water. Do not use organic
solvents to clean the Sensor Cap. Using an organic solvent to clean the
Sensor Cap may cause permanent damage to the cap. For example,
alcohol will dissolve the outer paint layer and other organic solvents will
likely dissolve the dye in the cap. Dissolving or scratching the paint or
dye layer will cause erratic dissolved oxygen measurements.
To disinfect the probe, soak the probe in 3% hydrogen peroxide for 15 to
30 minutes and then rinse it with clean water.

Sensor Cap Replacement

The sensor cap should be replaced about once per year but may last
longer. It should also be replaced if it is cracked or damaged (see
Troubleshooting section for instructions on how to inspect the cap for
damage). The instruction sheet shipped with the replacement O\DO
sensor cap includes the calibration coefficients specific to your sensor
cap.
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