SQ pumps have integrated dry-running protection that does not require a corresponding level sensor. If there is a lack of water, the pump is switched off after the preset current value is reached to prevent the motor from overheating. To this end, the software integrated into the CU 300/301 controller verifies the level of power consumption. If power consumption is too low, the pump is switched off for five minutes. Once this time has passed, an automatic restart is attempted.
The current value at which the pump is to switch off is configured during commissioning of the SQE using remote control R100 or Grundfos GO. Recommended adjustment values are provided in the operating instructions. If the performance curve changes, a new switch-off value will have to be calculated using the PC tool ‘SQE – calculating variable speed’.