Grundfos Control MPC Montage- Und Betriebsanleitung Seite 47

As standard, there is a 10-seconds detection hysteresis.
Factory settings
The function is enabled in pressure-boosting applications with the
settings in the table.
Start/stop band: 25 %
30 % of the rated flow rate of one
Minimum flow rate:
pump
Distribution above
50 %
setpoint:
The function is disabled in all other applications.
Related information
6. Overview of control variants
8.3.4 Setpoint (1.2.2)
8.6.28 Digital inputs (4.3.7)
8.6.30 Analog inputs (4.3.8)
8.6.25 Pilot pump (4.3.2)
Pilot pump
Description
In applications with low flow variations, a system with a pilot pump
is advised.
To obtain a high efficiency the recommended pilot pump size is
20-25 % of Q of the main pump.
nom
Both cut in and cut out speed for pilot pump and main pump is
calculated using the pump curve data.
The pilot pump needs to be activated using the PC Tool.
We recommend to upload pump data for the pilot pump or
go to menu and enter them manually.
1. Enable or disable the pilot pump.
2. Changeover to pilot pump: Set the flow for the changeover
from main pump to the pilot pump. Factory settings are 75 % of
the pilot pump Q .
nom
3. Time hysteresis: Set the delay time for the changeover to a
stable low flow before the changeover.
4. Changeover to main pump: Set the flow for the changeover
from pilot pump to the main pump. Factory settings are 95 % of
the pilot pump Q .
nom
5. Time hysteresis: Set the delay time for the changeover to a
stable low flow before the changeover.
6. Pressure band cut-in: Set the pressure band in percentage of
the setpoint. The pressure band is used for cut-in or cut-out of
pumps.
• Main pumps cut-out when the pilot pump ramps up to a
stable setpoint "+ or and" pressure band outlet pressure
• Pilot pump cut-out when the main pumps ramps up to a
stable setpoint "+ or and" pressure band outlet pressure
• If the pilot pump is running at 100 % and the pressure band is
below the setpoint-pressure band, the main pumps will cut in.
Setting via the operating panel
• Settings > Secondary functions > Pilot pump.
1. Enable pilot pump
• Set: Changeover to pilot pump
• Set: Time hysteresis
• Set: Changeover to main pump
• Set: Time hysteresis.
2. Set: Pressure band cut-in.
Factory settings
The function is disabled.
8.6.26 Soft pressure build-up (4.3.3)
The soft pressure build-up program will be disabled if the
multisensor function is activated.
Soft pressure build-up
Description
The function is typically used in pressure-boosting applications and
ensures a smooth startup of systems with for instance empty pipes.
Startup takes place in two phases:
• Filling phase (1): The pipes are slowly filled with water. When
the pressure sensor of the system detects that the pipes have
been filled, Phase 2 begins.
• Pressure build-up phase (2): The system pressure is
increased until the setpoint (SP) is reached. The pressure
buildup takes place over a ramp time. If SP is not reached
within a given time, a warning or an alarm can be given, and the
pumps can be stopped at the same time.
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