ETATRON D.S. HD-PH, Instruction Manual

Page: 37 / 96

must not be forgotten that adequate time must be allowed for the additive to
become uniformly distributed, otherwise the value read on the display will differ
from the real system state.
All our pumps are tested at their maximum working pressure; consequently,
if the plant is operating at a lower pressure, the maximum discharge of the
pump will be greater than the specified value.
8.2 HD-PH
(
CALIBRATION
)
All the pH pumps are calibrated at the works, so that only small regulating adjust-
ments are required on the occasion of installation. These are due for the most part
to the type of electrode used and the working temperature prevailing in the plant,
since especially the latter exerts a considerable influence on the pH value. We
would in any case advise that the calibration curve be checked at least once a
month, going through the routine described below.
When checking the curve, use two buffer solutions at pH 4 and pH 7 if you wish to
work in the acid range or, alternately, pH 9 and ph 7 if you wish to work in the alka-
line range.
• Dip the elctrode into a pH 7 buffer solution for few seconds.
• Adjust “
∆
0” (17) trimmer until display shows pH 7.00
• Dip the elctrode into a pH 4 or pH 9 buffer solution for few seconds.
• Adjust “pH/mV” trimmer (16) until display shows pH value according to the
used solution.
37
English
ENG