Pump Controls; Commissioning The Pump; Calibration; Pb-Ph Specific Electrical Fault - Etatron PB Serie Manual Del Usuario

10.4 - PB-PH PUMP CONTROLS (Fig. 26)
1 - ON/OFF light switch "green"
2 - Level alarm L.E.D. "yellow"
3 - Pulse frequency L.E.D. "red"
4 - Injection frequency adjustment knob
5 - Acid/alk selector
6 - Acid signal L.E.D.
7 - Alkaline signal L.E.D.
8 - Gain calibration "pH/mV"

9 - "0" calibration

10 - 3 digits display
11 - Temperature compensation knob
12 - Set calibration trimmer
13 - Meter/set point selector

10.5 - COMMISSIONING THE PUMP

A. Install the metering pump as described in Chapter 3.0 "PUMP INSTALLATION"
B. Place the electrode in the electrode holder.
C. Connect the electrode to the metering pump by means of the male BNC connector (T) rotating it through
90°C.
D. Position the "FUNCTION SELECTOR" (13) at pH set and then use the tool supplied with accessories to adjust
the "pH set" (12) trimmer to the required pH value.
E. Position the function selector (13) at "pH met". Use the "ACID/ALK" switch (5) to select the required type of
intervention (acid or alkaline). Example: if the intervention point is set at pH 9 and an acidification is
required, set the switch to ACID. The pump will then start dosing the additive every time the pH rises above
9. If it is desired to alkalinize the system, set the switch to ALK, in which case the pump will come into oper-
ation every time the pH drops below 9.
F. Since the temperature of the liquid influences the measured pH value, set the "temperature compensation
trimmer" (11) to the temperature existing in the system to obtain an automatic correction of the pH value
ascertained by the probe.
G. Use the FLOW knob (4) to set the number of pulse per minute, reducing or increasing the pump discharge
according to requirements. In this connection it 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 may be greater than the specified value.
10.6 - CALIBRATION
All PB-PH pumps are calibrated at the factory at a temperature of 20°C, small regulating adjustments are
required on installation. These are due to the type of electrode used and the working temperature prevailing in
the plant, especially the latter exerts a considerable influence on the pH value. Please note temperature error
can be compensated by operating the "temperature compensation trimmer" (11).
The adjustments enabling calibration are located on the front panel. These adjustments are necessary at
regular intervals, as the electrodes not only tend to change their physico-chemical composition, but will also
modify their measuring efficacy.
When checking the calibration, 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 alkaline range. We would advise that the calibration
curve be checked at least once a month, using the routine described below.
• Adjust temperature manual compensation trimmer "°C" (11) according installation temperature.
• Adjust "0" (9) trimmer until display shows pH 7.00
• Dip the electrode into a pH 4 or pH 9 buffer solution for few seconds.
• Adjust "pH-mV" trimmer (8) until display shows pH value according to the used solution.
10.7 - PB-PH SPECIFIC ELECTRICAL FAULTS
THE PUMP DOES NOT MEASURE CORRECTLY
a. Check the calibration of instrument
b. Check the efficacy of the electrode
THE PUMP FAIL TO DOSE
a. Make sure the "set point" has been correctly set
b. Make sure the "ACID/ALK" switch is on the right position, i.e. that it concords with the required dosing.
N.B. When removing the pump from the plant use great care in detaching the delivery hose from the connector
nipple because it could contain some residual additive.
• 49 •
PB-PH
Fig. 26