Wilo Star S 33 FC 4190420 - circulator pump incorporates a cast iron housing, three speed motor (Low/Med/High) and a built-in, removable check valve. Wilo Star S 33 FC is among the most popular and most versatile circulator pump models on the market. Pump’s performance parameters cover nearly all traditional heating applications – from radiant and baseboards, to fan coils and zoning and many others. 3 speeds allow to set up the circulator pump in a way, that matches the system’s requirements, while wet rotor design allows it to be virtually silent while operating. Applications: Closed loop radiant heating & snow melting systems. Baseboard / Radiator /Fan coil heating and other hydronic heating applications.