McDonnell & Miller FS5-3/4 General Purpose Liquid Flow Switch

The McDonnell & Miller FS5-3/4 General Purpose Liquid Flow Switch is an inline device designed for dependable flow monitoring in HVAC, heating, and industrial piping. It features a 3/4 inch nominal size with threaded end connections, making it a true In-Line flow switch, and a SPDT snap switch that provides a clear on/off signal when flow changes.

Electrical ratings include up to 7.4 A at 120 VAC and 3.7 A at 240 VAC, with a 125 VA input supply rating at 120/240 VAC (50/60 Hz). Flow performance covers 1.5–15 GPM during flow and 1.1–10 GPM with no flow, while it handles temperatures from 32 to 300 °F and tolerates up to 150 PSI. UL and CSA listed, this unit is built for safety and reliability.

A compact, robust design features low flow capacity and an adjustable sensitivity screw for precise control across different systems.

• 3/4" nominal size with threaded end connections
• SPDT snap switch for reliable signaling
• Flow: 1.5–15 GPM (flow) / 1.1–10 GPM (no flow)
• Temperature range 32–300 °F; pressure rating 150 PSI
• Adjustable sensitivity screw; low flow capacity
• UL and CSA listed for safety and compliance