Settings; Setting The Pressure Switches; Setting The Diaphragm Tank Precharge Pressure; Maintenance - Grundfos Hydro Multi-S CM Montage- Und Betriebsanleitung

11. Settings

11.1 Setting the pressure switches

Warning
The cut-out pressure must under no
circumstances exceed the maximum operating
pressure of the pump and tank.
Each booster system is factory-tested, and the pressure switches
are adjusted to ensure optimum performance.
During installation and commissioning, it might be necessary to
adjust the settings to optimise operation in the actual installation.
See fig. 6.
Fig. 6 Pressure switch
11.1.1 Setting the cut-out pressure
To set the cut-out pressure (p
cut-out
1. Turn the P1 screw clockwise to increase the cut-out pressure
and counter-clockwise to decrease the cut-out pressure.
See fig. 6.
2. Set the cut-out pressures with a difference of 0.3 to 0.5 bar
respectively (cascade step) on each pressure switch.
3. Start the pump, and check by reading the pressure gauge
whether the desired cut-out pressure has been obtained for
each pressure switch.
11.1.2 Setting the differential pressure
To set the differential pressure (p
to increase the differential pressure and counter-clockwise to
decrease the differential pressure. The cut-out pressure remains
unchanged. See fig. 6.
The differential pressure must be set to the same value on all
pressure switches.
11.1.3 Cut-in pressure
The cut-in pressure (p ) will be automatically set when the
cut-in
differential pressure is set.
p = p - p
cut-in cut-out diff.
To check whether the cut-in pressure is as desired, proceed as
follows:
1. Start the pump, and check by reading the pressure gauge
whether the desired cut-out and cut-in pressures have been
obtained.
2. Repeat the above setting procedures until the right cut-in and
cut-out pressures have been obtained.
10
), proceed as follows:
), turn the P2 screw clockwise
diff.

11.2 Setting the diaphragm tank precharge pressure

When the pump cut-in pressure has been determined, the
required precharge pressure of the diaphragm tank can be
adjusted roughly to 90 % of the pump cut-in pressure.
Precharge pressure = 0.9 x p
cut-in
The tank precharge has to be checked/adjusted when the
discharge pipe is empty.

12. Maintenance

Warning
Before starting work on the pumps, make sure
that the power supply has been switched off.
Lock the mains switch with a padlock to ensure
that it cannot be accidentally switched on.

12.1 Pump

Pump bearings and shaft seals are maintenance-free.
12.2 Settings
To ensure reliable and correct operation, the precharge pressure
of the diaphragm tank and the setting of the pressure switches
should be checked regularly and at least once a year.

12.3 Frost protection

If the booster system is not used during periods of frost, the
manifolds, pumps and diaphragm tank should be drained to avoid
damage.
.