The 4” submersible pumps of the series ST have been designed to be installed in 4” wells (100mm) and to pump clean water or water with the slight presence of sand (250 g/m³ max.), without suspended solids.
Temperatures not higher than 35 °C for domestic use (CEI EN 60335-2-41) or 40 °C for other use.
The innovative floating impellers, besides that the blockage problems caused by the presence of sand are reduced, also the axial thrust is remarkably reduced granting a longer life to the motor.

Further the particular construction of the non-return valve integrated in the upper head protects the impellers and diffusers from the weight of the column and eventual water hammers.