McDonnell & Miller FS5-1 General Purpose Liquid Flow Switch

The McDonnell & Miller FS5-1 General Purpose Liquid Flow Switch is engineered for reliable inline flow monitoring in boiler and hydronic systems. This 1 inch nominal size inline flow switch features threaded end connections and a durable SPDT snap switch to deliver dependable operation across a variety of fluids.

With adjustable sensitivity, it detects both low and high flow conditions and triggers alarms or control devices as needed. The unit is UL and CSA listed, and is built to endure environments from 32 to 300°F and up to 150 psi, making it versatile for many applications.

Electrical performance and flow specification enable wide compatibility: current ratings of 7.4 A at 120V AC and 3.7 A at 240V AC, with an input supply rating of 125 VA at 120/240 VAC (50/60 Hz). Flow ranges are 1.5 to 15 GPM (flow) and 1.1 to 10 GPM (no flow), ensuring reliable activation as conditions change. This general purpose liquid flow switch is ideal for pumps, boilers, and water systems where precise flow sensing matters.

• In-Line Type design for straightforward installation with threaded end connections
• Nominal size 1 inch for versatile piping compatibility
• SPDT snap switch contacts for flexible control
• Adjustable sensitivity via calibration screw
• Rugged and compliant with UL and CSA listings and wide temperature/pressure tolerances