Research And Insight

Soft pressure build-up

The Grundfos CU 351 pump control unit incorporates a 'Soft pressure build-up' function, which ensures a smooth start-up of systems containing empty pipes, for example.

It can be used in applications such as:

  • Irrigation
  • Water supply installations with an unstable power supply, in order to reduce water hammer.

Start-up takes place in two phases as the illustration shows.

  • Filling phase
    The pipework is slowly filled with water. When the pressure sensor of the system detects that the pipework has been filled, phase two begins.
  • Pressure build-up phase
    The system pressure is increased until the setpoint is reached. The pressure build-up takes place over a ramp time. If the setpoint 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.

The smooth start-up of the system results in:

  • Reduced water hammer effect
  • Increased comfort and security for consumer

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