Variable-Pressure Flow Switches

Accurate even in applications where pressure fluctuates regularly, these flow switches split flow into two paths and measure their difference in pressure drop to calculate the flow rate of liquid. They activate or deactivate equipment when the flow rate reaches your set point. Tighten or loosen the adjustment screw to choose your set point anywhere within the range. They measure accurately no matter their mounting orientation. All are single pole, double throw (SPDT) and can either turn one device from off to on (normally open) or on to off (normally closed). Rated NEMA 4X and IP66, they seal out dust and protect against washdowns and corrosion.
These switches are calibrated with water. They can also be used with other liquids but may not measure accurately if their viscosity is significantly different.
For technical drawings and 3-D models, click on a part number.
Set Point, gpm | Max. Pressure | Temp. Range, °F | Voltage | Max. Switching Current | Conduit Trade Size | End-to-End Lg. | Each | |
Bronze Body | ||||||||
---|---|---|---|---|---|---|---|---|
1/4 NPT Female | ||||||||
0.3 to 2 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 0000000 |
0.4 to 3 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
0.5 to 4 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
1/2 NPT Female | ||||||||
0.3 to 2 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
0.4 to 3 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
0.5 to 4 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
0.5 to 6 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
1.5 to 10 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
3/4 NPT Female | ||||||||
0.5 to 6 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
1.5 to 10 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
2 to 15 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
3 to 20 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
1 NPT Female | ||||||||
2 to 15 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
3 to 20 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
4 to 30 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
5 to 40 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
1 1/2 NPT Female | ||||||||
4 to 30 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
5 to 60 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
15 to 100 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 1/16" | 00000000 | 000000 |
2 NPT Female | ||||||||
5 to 40 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 3/16" | 00000000 | 000000 |
15 to 100 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 3/16" | 00000000 | 000000 |
30 to 200 | 400 psi @ 70° F | -30° to 212° | 120V AC/ 175V DC | 180 mA @ 120 V AC 250 mA @ 175 V DC | 1/2 | 3 3/16" | 00000000 | 000000 |
Insertion Flow Switches

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.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Thread Type | Gender | For Pipe Size | Set Point Range, gpm | Max. Flow Rate, gpm | Set Point Adjustment Method | Paddle Material | Max. Pressure | Temp. Range, °F | Max. Switching Current @ Voltage | Body Ht. | Environmental Rating | Specifications Met | Each | |
Brass Body with Brass Fittings | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Threaded Connection | |||||||||||||||
1 | NPT | Male | 1 2 4 6 | 4.9 to 17.6 13.7 to 56.4 35.3 to 118 60.3 to 245 | 27 105 397 900 | Removable Layered Paddles, Trimmable Paddles | 304 Stainless Steel | 160 psi @ 70° F | 33° to 225° | 3.7 A @ 240 V AC 7.4 A @ 120 V AC | 5" | NEMA 4X | C-UL Listed, UL Recognized Component | 000000 | 0000000 |