McDonnell & Miller FS4-3T3-3/4 General Purpose Liquid Flow Switch

General Purpose Liquid Flow Switch for reliable flow sensing in heating, cooling, and general process applications. The McDonnell & Miller FS4-3T3-3/4 General Purpose Liquid Flow Switch uses a paddle-type sensing element and an SPDT snap switch to provide precise on/off control across a broad flow range.

Nominal size 3/4 inch with threaded x threaded end connections, this unit withstands up to 160 PSI and temperatures from 32 to 300°F. Electrical characteristics include 7.4 A at 120 VAC and 3.7 A at 240 VAC, with an input rating of 125 VA at 120/240 VAC (50/60 Hz). Flow specs cover 2–4.5 GPM in operation and 1.2–4.1 GPM no-flow conditions.

Durable construction includes a hardened stainless steel bearing and sealed Monel bellows, making it suitable for demanding liquids. The paddle design is universal for compatibility, and UL/CSA listings ensure compliance.

• Sensitivity adjustable screw lets you set the switch point precisely for your flow conditions
• Two electrical knock-outs included for easy wiring and panel routing
• Hardened stainless steel bearing provides long-life performance in challenging environments
• Sealed Monel bellows for reliable leak-free operation and chemical compatibility
• Nominal size 3/4 in with threaded x threaded end connections