The HS-series is a submersible single-phase portable drainage pump and the HSZseries is automatic. The automatic operation, controlled by a single float switch, reduces consumption and extends operating life. Though the HS & HSZ are a singlephase unit, the pumps have the durability equivalent to three-phase drainage pumps, since the wear parts are made of abrasion-resistant materials. The side discharge, spiral design allows smoother passage of the sucked solid matters. The shaft-mounted agitator prevents “Air Lock” that tends to take place on vortex or semi-vortex pumps.