Pentair NOCCHI WP/Multi EVO-A Instructions De Service page 20

ENGLISH
the check valve in Figure 3 serves to pre-
vent emptying of the pump under a siphon
effect at the time of shutdown, so that
liquid stays in the pump body for subse-
quent start-up.
if there is no foot valve or check
valve on the suction port, filling
must be repeated before each
start-up.
if the pump has difficulty in in-
creasing pressure, repeat opera-
tions 1 to 10. if, after several at-
tempts, the pump does not operate
correctly, see the fault section "quick
troubleshooting guide"
Pressure switch adjustment (Figure 4)
the pressure switch on/off pressure val-
ues are set in the factory.
this section explains how to change the
pressure switch settings to adapt it to the
system characteristics.
• loosen the differential nut (1) com-
pletely;
• Adjust the minimum intervention nut
(2) to set the contact closing value
(pump start-up); when turned clock-
wise, the start pressure is increased,
and vice versa is decreased;
• tighten the differential nut (1) to ob-
tain the required cut-off pressure.
Pump start-up
use the electric pump according
to the performance specifica-
tions as stated on the data plate.
Always avoid operation of the
pump with the upline shutoff
valve closed (suction side). Dry
running of the pump can lead to over-
hearing and damage to the pump itself.
20 20
Never run the pump with the
shutoff valve downline (delivery
side) completely closed. in this
case, the water in the system reaches
very high temperatures, with the risk of
damage to equipment and scalding in the
event of escape of the liquid. in this situa-
tion, turn off the pump and leave the sys-
tem to cool.
Never use the pump in the event
of cavitation, as this can cause
damage to the hydraulic compo-
nents.
Pressure on the downline side of
the pump (delivery side) must
never exceed the maximum op-
erating pressure PN as indicated on the
pump data plate (see "Application limits"
Figure 5). Pressure downline of the pump
is obtained from the sum of the pressure
delivered and the pressure on the suction
side (gravity for installations with negative
suction head, aqueducts, or water system
where admissible or required).
1. Check that the shutoff valves downline
of the pump (delivery side) and upline
of the pump are in the open position.
2. Start the pump.
3. if the pump does not start up correctly,
on reaching the operating conditions in
a short time, the pump shuts down.
4. in this case repeat the "Pump priming"
phase.
mAINTENANCE
Before any intervention on the
system, disconnect the electrical
mains. Ensure that the electrical
power supply cannot be restored inadver-
tently.