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6.3.10 CAL – Calibration (continued)
To calibrate a CCD system, a liquid at approximately the maximum allowable conductivity
is introduced into the system. Use a mixture of tap water and condensate, to simulate
condensate at approximately the maximum allowable conductivity level (the set point).
5 litres (1.3 US gallons) will be plenty for most systems. Use the Spirax Sarco MS1
conductivity meter to check the conductivity. Close both stop valves (Figure 9, page 17)
and open the drain valve and 'water for flushing and calibration' valve. Pour in the prepared
water, and let it run through the system until bubble free. Close the drain valve. Allow the
display to settle for two minutes. Calibrate the controller as described in the main text. It
is advisable to check calibration after the system has been running for a few days, then
periodically depending on the individual plant conditions. Consult your water treatment
specialist if in any doubt.
Note: Ensure purge time is set to zero and a Pt100 is installed.
6.3.11 PUL – Pulsed blowdown valve operation
This feature is suitable for use with solenoid or pneumatic valves only. It must not be used
with motorised valves. If 'on' is selected the valve will open for 10 seconds and close for
20 seconds until the conductivity drops below the Set Point (plus the corresponding
hysteresis). If 'oFF' is selected, the valve will remain open continuously until the conductivity
drops below the Set Point (plus the corresponding hysteresis).
Press the
OK
button to show the current setting, and press
to toggle between pulse
OFF or On.
Press the
button to confirm your selection and move to the next menu option.
6.3.12 4 - 20 mA output retransmission
The controller outputs the current loop standards in common use. It retransmits the actual
conductivity or TDS with respect to the full-scale range, for example;
0 µS = 4 mA and 100 µS = 20 mA.
Press the
button to confirm your selection and move to the next menu option.
Note: If a purge time has been selected, the 4 - 20 mA (0 - 20 mA) is held at the value
recorded at the end of the last purge cycle.
6.3.13 tc – Internal temperature compensation
If a Pt100 temperature sensor is not fitted, enter an estimated average water temperature. If
a Pt100 is fitted and measures a temperature between 100 - 250°C, the water temperature
will be shown (not flashing). With a Pt100 fitted, this menu cannot be edited.
To enter a temperature if a Pt100 is fitted:
Press the
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