Nortec DRAABE Pure Water System - Manual (Page 21)

Created: 21.09.2006
Changed: 29.02.2008
Printed: 02.03.2009
page 21 of 59
3.2.5 Functional Description of the Dosing unit
Process water is supplied by a fully automatic, one stage dosage facility. The pure water
produced by the system is mixed with 0,5% (fixed setting) of the hardening concentrate
"Aqua-Plus" so as to ensure constant water hardness in the range 8°-10° dH (138-173
ppm).
CAUTION: Only use "Aqua-Plus"! Experience has shown that with other hardening concen-
trates, which may not contain enough fungicides, germination of the system can set in.
The quality of the process water ought to be checked once a week. When the DRAABE
hardening concentrate "Aqua-Plus" is used, this can be done with a conductance meas-
urement (but not with a titration test or hardness test strip).
The following procedure should be followed when taking this measurement:
1.
let the first 10 litres drain off
2.
catch the next 10 litres in a clean container
3.
stir thoroughly
4.
measure the conductance with a calibrated device (500 – 700 µS = 8° - 10° dH (138-
173 ppm)).
IMPORTANT: If a different hardness concentrate is used, ask its manufacturer which
measuring method should be applied.
Aqua - Plus
Dosing unit
0,5%
Figure 10: Dosing unit