McDonnell FS 251 Flow Switch – FS254 Flow Switch

2021-12-29

Installation Guide of FS 251 Flow Switch – FS254 Flow Switch

General-Purpose, Liquid Flow Switches, the Series FS250 – FS251 (NEMA1 version), and FS254 (NEMA4 version). These flow switches incorporate key changes to address customers’ expressed needs for greater reliability and lower flow sensing capabilities in a general-purpose flow switch.

Features and Benefits of FS 251 Flow Switch – FS254 Flow Switch

Common switching mechanism for both the FS251 and FS254
Measured flow-rate sensing of 5.8 GPM in 1” pipe (2.2 fps) in horizontal pipe installations, which is 18% lower than the measured flow of comparable general purpose flow switches from major competitors. (Refer to submittal MM-627 for flow rates.)
1-inch NPTM brass pipe connection
1”, 2”, 3” and 6” Stainless steel paddles standard
Section IV boiler ratings of 250º F and 160 PSIG
No lead construction
Housing materials:
FS251 – stamped sheet steel base with glass reinforced
polycarbonate cover
FS254 – Cast aluminum base and cover

Universal Design Serves the Widest Variety of Applications

For starting or stopping electrically operated equipment such as signal lights, alarms, motors, automatic burners, metering devices, and others
Replacement for common flow switches from Johnson/Penn, Potter/Taco, Watts, Hydrolevel, and other manufacturers

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