McDonnell & Miller FS4-3T1-1 General Purpose Liquid Flow Switch

The General Purpose Liquid Flow Switch is a McDonnell & Miller FS4-3T1-1 unit featuring a paddle-type, universal design for 1-inch piping with threaded ends. This SPDT snap switch provides reliable control across heating, cooling, and process lines, delivering durable performance in demanding environments.

Nominal Size: 1 inch. End connections: Threaded x Threaded. Temperature rating: 32–300°F. Pressure rating: 160 PSI. Flow rate: 5–11.5 GPM (flow); 3.2–11 GPM (no flow). Electrical ratings include 7.4 A at 120 VAC and 3.7 A at 240 VAC, with an input of 125 VA at 120/240 VAC (50/60 Hz).

Designed for long service life, it features a sensitivity-adjustable screw, (2) electrical knock-outs, a hardened stainless steel bearing, and a sealed Monel bellows. UL and CSA listed, this flow switch integrates easily into a wide range of commercial and industrial systems.

• Sensitivity adjustable screw
• Two electrical knock-outs
• Hardened stainless steel bearing
• Sealed Monel bellows
• UL and CSA approved