McDonnell & Miller FS4-3T1-3/4 General Purpose Liquid Flow Switch

General Purpose Liquid Flow Switch is essential for reliable flow monitoring in boilers, pumps, and process lines. The FS4-3T1-3/4 from McDonnell & Miller is a rugged, universal paddle-type switch with 3/4 inch nominal size and threaded x threaded end connections, designed for versatile control in demanding applications.

Designed for durability, it features a sealed Monel bellows and a hardened stainless steel bearing, plus (2) electrical knock-outs for easy installation in control panels and pipes.

Key specifications include a flow range of 4.4–10.5 GPM (flow) and 2.6–9.8 GPM (no flow), a temperature rating of 32–300°F, and a pressure rating of 160 PSI. The sensor uses an SPDT snap switch and accepts 3/4 in nominal size with threaded x threaded end connections. Electrical ratings are 7.4 A at 120 VAC and 3.7 A at 240 VAC, with a 125 VA input at 120/240 VAC and 50/60 Hz. UL and CSA listings ensure safety and compliance.

• Nominal size: 3/4 in; end connections: threaded x threaded
• Flow range: 4.4–10.5 GPM (flow) / 2.6–9.8 GPM (no flow)
• Temperature range: 32–300°F; Pressure rating: 160 PSI
• Current rating: 7.4 A @ 120 VAC; 3.7 A @ 240 VAC
• SPDT snap switch with sensitivity adjustable screw
• Includes (2) electrical knock-outs
• Materials: sealed Monel bellows; hardened stainless steel bearing
• UL and CSA listed