Honeywell WFS-6000

The Honeywell WFS-6000 is a paddle-type water flow switch that detects when liquid flow in a line exceeds or drops below an adjusted rate. A segmented paddle inserted in the flow stream actuates an SPDT contact system: wire it to close one circuit and open a second as flow crosses the setpoint — the classic interlock proving chilled-water flow before a chiller starts, protecting pumps against dry running, or raising a no-flow alarm.

Designed for water and fluids harmless to brass and phosphor bronze (not for hazardous fluids or lines below 0 °C), the WFS-6000 covers pipe diameters from 1" to 6" with trimmable paddle segments, giving one SKU an enormous application range across HVAC and industrial water circuits — including high salt/chlorine content water.

There is only one model code — and that is the point. Unlike most flow switches, the WFS-6000 is not ordered by pipe size: a single part covers 1" to 6" because the paddle ships as three segments that the fitter trims to the line. You do not need to specify a variant, a range or an orifice. The same switch is designated WFS-1001-H in some markets and documentation — if a drawing or a client's spare-parts list calls for a WFS-1001-H, it is this switch.

Getting the installation right matters more than the selection. Mount into a 1" NPT tee with the paddle square to the flow and the arrow pointing downstream, allow five pipe diameters of straight run either side, and trim the paddle to the pipe size before fitting — an over-long paddle in a small line will foul, and an untrimmed paddle in a large line will not lift. Do not use it on lines that can freeze or on fluids that attack brass.

Fit a flow switch when a chiller or heat pump needs proof of chilled or condenser water flow before the compressor is allowed to start, when a pump must be stopped on loss of flow, when a heat exchanger or process line needs a no-flow alarm, or when an existing paddle switch is chattering or has stopped making at the setpoint.