ITT McDonnell Miller FS5-1 1" FNPT SPDT Snap Flow Switch 120/240VAC 15 gpm

FS5-1 Snap Flow Switch for 1-Inch Pipe

The ITT McDonnell Miller FS5-1 is a brass-body snap flow switch designed for 1-inch NPT piping. It provides SPDT contact operation for general-purpose electrically operated control circuits. The unit is rated for ambient and media temperatures between 32 and 250 degrees Fahrenheit. It suits hydronic heating, cooling, and industrial process applications requiring flow verification.

Installation uses standard 1-inch FNPT threading

The switch threads directly into a 1-inch NPT pipe fitting with an overall height of 5.1 inches. Brass housing allows standard pipe sealant or tape without special tools. The fixed flow actuation point is set at 1.5 gpm; systems with variable or lower flow rates will not trigger the switch reliably. Electrical connections accept standard spade or screw terminals for 120 or 240 VAC supply.

SPDT contacts rated 22.2 A locked rotor at 240 VAC

The single specification that determines fit is the contact rating: 22.2 amps at 240 VAC locked rotor and 3.7 amps full load, with 44.4 amps locked rotor and 7.4 amps full load at 120 VAC. This rating must exceed the connected load inrush and steady-state current. Buyers controlling loads above these limits must select a different switch or add an intermediate relay.