Description
The Xylem-McDonnell & Miller FS4-3T3-3/4 is a low-flow, single-pole double-throw (SPDT) float switch designed to monitor liquid levels in HVAC systems. It is usually used in condensate drains or chilled water systems and has an inbuilt float. The switch modifies its electrical contacts and activates when the liquid level rises to the point where the float is buoyant. Two output connections are present in this SPDT design: one that opens and one that closes when the device is activated. This adaptability makes many control schemes possible. For example, the switch can be set to start a pump when the liquid level drops below a given point and stop it when the level increases enough.
