Pressure Setting - Grundfos SCALA2 Installation And Operating Instructions Manual

7.3 Pressure setting

The pump can be set to provide a water pressure
between 1.5 to 5.5 bar (22 to 80 psi) at intervals of
0.5 bar (7 psi).
The factory setting is 3 bar (44 psi).
We recommend you to use the default
pressure of 3.0 bar (44 psi) which will suit
most applications.
The difference between the positive inlet
pressure and outlet pressure must not
exceed 3.5 bar (51 psi).
Example: If the inlet pressure is 0.5 bar (7
psi), the maximum outlet pressure is 4 bar
(58 psi).
If you set the pressure too high, this might
cause the pump to operate for up to three
minutes after the tap is turned off. The
maximum setpoint is 4 bar (58 psi).
You can achieve more energy efficient
operation and prolong the life of the pump
by making sure that the tank precharge
pressure is optimised to 70 % of the
setpoint of the pump. See
the table below for recommended optimal
tank precharge pressure.
Optimal tank precharge pressure
Optimal tank precharge
Setpoint
[bar (psi)]
5.5 (80)
5 (73)
4.5 (65)
4 (58)
3.5 (51)
3 (44)
2.5 (36)
2 (29)
1.5 (22)
1) Only with positive inlet pressure. The factory precharge
pressure is 1.8 bar.
Related information
4.2 System sizing
pressure setting
[bar (psi)]
1)
3.9 (57)
1)
3.5 (51)
1)
3.2 (46)
1)
2.8 (4.1)
2.5 (36)
2.1 (30)
1.8 (26)
1.4 (20)
1.1 (16)
7.3.1 Boosting from a well or a tank
If you are boosting from a well or a tank, make sure
not to set the pressure setpoint too high. The
difference between the inlet pressure and outlet
pressure must not exceed 3.5 bar (51 psi).
Maximum setpoint
Well application
Tank below ground level
Tank above ground level
Boosting from a well
Boosting from a tank
[bar (psi)]
3.0 (44)
3.5 (51)
4.0 (58)
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