Pump Control - Grundfos ALPHA2 L Series Installation And Operating Instructions Manual

During operation, the pump head will be controlled according to the
principle "proportional-pressure control" (PP) or "constant-pressure
control" (CP).
In these control modes, the pump performance and consequently the
power consumption are adjusted according to the heat demand in the
system.
In this control mode, the differential pressure across the pump is
controlled according to the flow.
The proportional-pressure curves are indicated by PP1 and PP2 in the
Q/H diagrams. See .
In this control mode, a constant differential pressure across the pump is
maintained, irrespective of the flow.
The constant-pressure curves are indicated by CP1 and CP2 and are
the horizontal performance curves in the Q/H diagrams. See
.
15