ENGLISH
8
System
design
pressure not
reached
Isolating valves or
stop valves partially
closed or obstructed
Open or check the
valves
Excessive
intake
and/or
delivery
pressure loss
Reduce the pressure
losses
Check for clogging in
the pipes
Presence of air in
the intake
Check the flanged or
threaded
connections and the
gaskets for any liquid
leaks
or
air
infiltrations, install air
bleed valves on the
delivery
line
if
necessary
The
three-phase
pumps rotate in the
inverse direction
Invert
the
two
phases on the panel
Pressure
switches
not
calibrated
correctly (if present)
Recalibrate
the
pressure switches or
replace them
Triggering
of
the
minimum
pressure
switch (if present)
due to a low level or
lack of liquid in the
intake manifold
Check the valves
upstream
of
the
intake manifold or
check
for
leaks.
Restore the liquid
level
Triggering
of
the
float switches.
Check or restore the
level in the tanks and
correctly adjust the
floats
11.4. CALIBRATING THE PRESSURE SWITCHES
The pressure switches are only present in sets with an EP, SP-
EFC or SP-MFC control panel.
The pressure switches are calibrated (at ambient temperature)
according to the following standard table:
Pressure switch calibration table:
Pump
sequence
Type of
operation
Calibrating
pressures
[bar]
Sets
Pump no. 1
(or pilot pump)
Pressure switch
no. 1
Stop
P1=P0-10%
Sets with 1
pump
Start
P2=P1-
Pmin
Pump no. 2
Pressure switch
no. 2
Stop
P3=P1-0.5
Sets with 2
pumps
Start
P4=P3-
Pmin
Pump no. 3
Pressure switch
no. 3
Stop
P5=P3-0.5
Sets with 3
pumps
Start
P6=P5-
Pmin
Pump no. 4
Pressure switch
no. 4
Stop
P7=P5-0.5
Sets with 4
pumps
Start
P8=P7-
Pmin
With:
P0 = max pressure in bar of pump no. 1 (or pilot pump) with
the opening closed
P1 - P8 = calibrating pressures in bar (see the following table)
ΔP = minimum differential in bar (see the following table)
NB: depending on the characteristics of certain types of pumps
(with flat curve), the pressure switch for pump no.1 (or pilot)
may be calibrated at a stopping pressure P1= P0
– 0.3 bar Any
diaphragm tanks must be calibrated by the user at a pressure
0.3-0.5 bar lower than the starting pressure of the pressure
switch of the last pump (minimum pressure).
Regulating range:
PRESSURE
SWITCH TYPE
PUMP P
STOP
PRESSURE
[bar]
MINIMUM
DIFFERENTI
AL
P
[bar]
MAXIMUM
DIFFERENTI
AL
P
2
[bar]
PY06
1.5 - 4.5
0.8 - 1.2
-
PY12
4.5 - 10.3
1.2 - 2.1
-
XMP A06
1 - 6
0.8 - 1.2
0.8 - 4.2
XMP A12
1.3 - 12
1 - 1.7
1 - 8.4
XMX A25
3.5 - 25
3.4 - 4.5
3.4 - 20
FSG 2NE – 9NE
1.4 - 4.6
1 - 1.2
1.2 - 2.3
FYG 22NE
2.8 - 7
1.2 - 1.6
2.3 - 2.7
Note: check directly on the installed pressure switches for the
identification code of the assembled model.
Adjustment procedure (see image fig. H):
completely loosen the regulating nut or screw “B” of
pressure switch 1 of pump no. 1 (in this
you have the
minimum differential ∆P)
start pump no. 1 by means of the manual control (or the
pilot pump when the set is provided with one);
slowly close the isolating valve downstream of the set
until obtaining the desired stop pressure (reading on the
pressure gauge), adjust pressure switch no. 1 by rotating
the nut or screw “A” until the contact clicks open, this
operation will stop the pump;
slowly open the isolating valve downstream of the set,
which causes a loss of system pressure until the contact
clicks shut for pressure switch no. 1(which is already set
with minimum
P), this operation will start the pump.
Check the adjustment by increasing and decreasing the
pressure downstream of the system, always using the
isolating valve;
perform the same operations for the set’s remaining
pressure switches. To adjust the start and stop of the
pumps, use the information provided above in the
“Pressure switch calibration table”
. Pay particular
attention to set the starting values for the pumps following
the first one, with decreasing pressure values to prevent
the simultaneous start of the pumps;
discharge the downstream pressure, set automatic
operation on the control panel, slowly open the isolating
valve downstream of the set, check the sequential
intervention calibration of the pumps at least twice to
further check the inversion of the starting order of the
pumps.