8
• Perform two-point calibration. The first calibration point is done in air (probe inserted in flow
cell without any solution). The air calibration is at 0.001
µ
S/cm. Once the probe is calibrated to
0.001
µ
S/cm then a second point is calibrated. It is recommend calibrating the second point with
the
HI7033
(84
µ
S/cm) calibration standard. Holding both tubing (bottom and side) the standard
is introduced into the flow cell through the bottom tubing until there is a 5-7.5 cm (2-3”) column
of solution in the side tubing. While holding both tubes the flow cell should be tapped gently to
dislodge any trapped air. Alternatively the raising and lowering of each tube to move the solution
through the cell. The column of solution should be observed to move as one tube is raised higher
than the other. Once the reading stabilizes the calibration point can be confirmed.
• After calibration the bottom tube of the flow cell is connect to the water source to be tested. The
other tube goes to waste. The water source should be turned on and adjusted to approximately
200-500 mL/minute. A graduated cylinder or beaker can be used to determine the flow rate. The
water should be allowed to flow for at least 1-2 minutes before taking a reading.
• For the measurement of high purity water it is important to use a temperature correction coefficient
(
β
) of 5.20%/°C. See setup options for changing the temperature correction coefficient. This setting
will adjust each reading by 5.20% for each 1 °C away from the reference temperature (default
25 °C). Using a temperature coefficient of 1.90%/°C (default) will result in higher readings
(>18.2 M
Ω⋅
cm) being observed for high purity water at a temperature colder than 25 °C.
FUNCTIONAL DESCRIPTION
