Avoid complicated inline installation—these flow switches insert into a tee or pipe outlet, so you don’t need to disassemble your pipeline. They have a paddle that’s pushed as your liquid moves through to determine flow. When the paddle reaches a set position determined by the set point, it activates or deactivates equipment. They are single pole, double throw (SPDT) and can either turn one device from off to on (normally open) or on to off (normally closed). They should be mounted vertically into a large-diameter horizontal pipeline, so liquid pushes the paddle.

These flow switches are calibrated with water. You can use them with other liquids, but they may not measure accurately if the liquid’s viscosity differs from water.

Switches with a brass or 316 stainless steel body have multiple paddles you can choose between to get you closest to your set point. For a higher set point, loosen the locking washers to remove the largest paddles. You can also trim the paddles to fine-tune your set point. The more you trim, the higher the set point.

Choose a fitting material that is compatible with the liquid you're running through your line. Brass and 316 stainless steel fittings resist impact better than Noryl plastic fittings. NEMA 4X rated switches protect against dust, weather, and washdowns.