Product Overview

Series FS250
General Purpose Liquid Flow Switches
FS254
FS251
• 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
• 1" NPTM Pipe Connection
• Sensitivity adjusting screw makes flow adjustment easy
• Single pole, double throw snap switch
• EPDM O-ring sealed
• Four stainless steel paddles included -
1", 2", 3" & 6" (25, 50, 80, & 150mm)
• Minimum temperature (fluid or ambient) 32°F (0°C)
• Maximum temperature 250°F (121°C)
• Maximum pressure 160 psi (11.2 kg/cm
2
)
• Models:
FS251 - NEMA1 enclosure
FS254 - NEMA4 enclosure
B
Dimensions, in. (mm)
ABCDEFG
FS251 3 1-1/2 2-7/32 7/8 8-7/16 2-15/16 3-3/8
(76) (38) (56) (22) (211) (75) (86)
FS254 3-1/4 1-5/8 3/4 1/2 8-3/8 2-3/4 3-7/8
(83) (41) (19) NPTF (213) (70) (98)
HJK LMN
(not shown)
FS251 1-11/16 1-1/2 1-1/8 3-7/16 2-1/16 1" 2-5/16
(43) (38) (29) (87) (52) NTPM (59)
FS254 2-1/4 1-1/2 1-1/8 3-7/16 1-7/8 1" 2-5/16
(57) (38) (29) (87) (48) NTPM (59)
O
Turn-in Radius
Flow Switches
McDonnell & Miller
Flow Switches
Flow Switches – Liquid