6.4.2
Conductivity measurement procedure
6.4.2.1 Generalities
The total dissolved solids (TDS) in water can be measured by conductivity (1) (expressed in
microsiemens per centimeter, µS/cm).
It allows to estimate the quality of the deminiralization.
The conductivity is the opposite of the resistivity.
6.4.2.2 “Water purifier outlet” conductivity
INTERPRETATION OF THE VALUE OF THE PURIFIED WATER CONDUCTIVITY
Conductivity<1 µS/cm
Class 2 water (according to ISO 3696)
Water of very good quality, no impact on the quality of the
analysis.
1 µs/cm<Conductivity<5 µS/cm
Class 3 water (according to ISO 3696)
If the desired water class is class 2:
Perform a "membrane outlet” conductivity measurement (see
paragraph 6.4.2.3)
Change the resin cartridges (see paragraph 6.4.5)
Conductivity>5 µS/cm
Perform a "membrane outlet” conductivity measurement (see
paragraph 6.4.2.3)
Change the resin cartridges (see paragraph 6.4.5)
6.4.2.3 “Membrane outlet” conductivity
This conductivity measurement is carried out at the storage tank inlet pipe.
6.4.2.3.1 Preparation
Close the storage tank valve.
Close the tap water valve.
Disconnect the inlet connection pipe of the storage tank.
Connect instead the pipe with its closed valve (supplied) to do the conductivity measurement.
Open the tap water valve.
(1) Gustafson, H., Behrman, A. S., Ind. Eng. Chem Anal. Ed. 1939, 11, 7, 355-357.
O-Classic
operator’s manual
version: 20.01.22
17
