After connecting the pump to the mains, the pump motor is switched off and the non-return valve is at rest: if this is not the case, the pump stops and the motor will never start.

In the normal case, however, the pump behaves as follows:

• If the hydraulic circuit upstream from the pump has a pressure higher than CUT-IN, the pump motor does not start, the priming is finished regularly.
• If the circuit is not under pressure (P<CUT-IN), the pump motor is started. In this case:
  • If the hydraulic circuit goes under pressure (P>CUT-IN) and there is no flow, for example because the delivery tap is closed, the motor is switched off 10 seconds after starting: the pump is primed.
  • If there is no flow or pressure for 20 seconds (P<CUT-IN), the pump goes into DRYRUN alarm and is switched off: the pump is not primed.
  • Finally, if there is flow, the pump is primed and runs normally.

If no pressure and flow is detected during normal operation (or during pump start-up) for 20 seconds, the pump will go into DRYRUN alarm and the motor will be switched off.

The pump control electronics will try to restart the pump until the dry running condition, i.e. the absence of flow and pressure, is no longer detected.

These restart attempts will be scheduled as follows:

• From the 1st to the 48th attempt: 1 restart every 30 minutes for 20 seconds each
• From the 49th attempt: 1 restart every 24 hours for 20 seconds each

The DRYRUN alarm can be reset manually: if after this reset the pump still does not detect flow and pressure, attempts will last 20 seconds.

The pump electronics have an anti-burping system that prevents false priming due to possible water bubbles.

Slight hydraulic leaks in the system downstream from the pump, when the system is under pressure and without flow, can lead to a gradual drop in pressure. This will cause the pump to start up periodically, causing damage to the motor, especially when starting at a short distance.

In this case, the electronics recognise the condition and activate the ANTICYCLING alarm. The alarm will prevent the pump motor from starting. The alarm can be removed manually. The alarm will still be removed automatically after 12 hours.