USF Wallace & Tiernan DEPOLOX 4, Manual

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6.3 ZERO CALIBRATION
1. Activate manual operation mode and press key "F" until "ZRO mg/l" is
displayed.
2. Close shut-off valve (page 10, item 20) to shut off sample water flow and
wait for 3 minutes.
3. Press key "E" to enter the zero current.
4. Open shut-off valve.
5. Press the MANUAL/AUTOMATIC key to leave the F menu.
NOTE:
After the sample water flow is shut off, the indication of the amplifier with drop -
very fast initially then after about 1 minute more slowly.
During initial startup, a waiting period of 5 minutes must be observed even if the
digital display drops to 0.00 after a few seconds of flashes.
The potentiostatic measuring principle allows a 2 month interval between calibrations.
6.4 ZERO CALIBRATION WITH CHLORINE-FREE WATER
If chlorine-free water is available, it may be used for zero calibration. In some cases
(e.g. in waterworks) chlorine-free water for zero calibration may also be obtained by
turning off the chlorinator.
6.5 ZERO CALIBRATION IN CASE OF A COMBINATION OF
CHLORINE AND OZONE
If a combination of these two methods of treatment is used, the sample water for
checking and calibrating the zero point must be taken off after the activated carbon
filter of the ozonisation system. This means that there must be a second sample water
take-off after the activated carbon filter of the ozonisation system in addition to the
sample water take-off in the return line to the pool. Both sample water lines must be
coupled by means of a three-way ball valve before the measuring cell. In this way,
the sample water line can be used alternatively for measuring or zero-calibration
purposes.
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