Watts FS20 - Manual

Series FS20
Nema 4X Flow Switch
Sizes: For pipes 1"- 6" (25 – 150mm)
Series FS20 provides accurate monitoring of liquid flow in
pipelines servicing water systems, heating systems, air condi-
tioning, and processing installations for industrial and commer-
cial applications. The FS20 series is recommended for use in
areas of high humidity for indoor or outdoor installations requir-
ing Nema 4X watertight, dust-tight, and corrosion-resistant
enclosures. The switch is epoxy coated and corrosion resist-
ant. The Nema 4X Flow Switch is designed to act as an auto-
matic control or safety device for liquid flow. The single-pole,
double-throw switch can be wired to start or stop a motor
when a flow or no flow condition exists or activate an alarm
when flow is inadequate. The switch then turns off the alarm
when adequate flow is restored. Series FS20 flow switches
can be installed in a tee for horizontal or vertical piping.
Features
• Beryllium copper paddle
• Brass alloy bellows seals switch assembly from the line
• Two adjusting screws, fine and coarse, to adjust sensitivity
• 1 ⁄ 2 " (15mm) threaded conduit hub accepts standard
vapor-proof connectors
• Removable cover for easy access to switch terminals
• Corrosion-resistant
• Zinc die-cast enclosure
• Epoxy-coated finish
• 1" (25mm) NPT connection
• Switch assembly independent and removable from
mounting adapter
Standards
Underwriter’s Laboratories Listed U.S.A. No. 11S1
Pressure-Temperature
Maximum Working Pressure: 150psi (10.3 bar) at 300ºF (148.9ºC)
For Commercial and Industrial Applications
ES-FS20
Job Name ––––––––––––––––––––––––––––––––––––––––––– Contractor ––––––––––––––––––––––––––––––––––––––––––––
Job Location ––––––––––––––––––––––––––––––––––––––––– Approval –––––––––––––––––––––––––––––––––––––––––––––
Engineer ––––––––––––––––––––––––––––––––––––––––––––– Contractor’s P.O. No. –––––––––––––––––––––––––––––––––––
Approval ––––––––––––––––––––––––––––––––––––––––––––– Representative ––––––––––––––––––––––––––––––––––––––––
Nema 4X Flow Switch
Paddles
3 in 1 Paddle – A segmented beryllium copper paddle is quick-
ly adaptable for 1" through 3" pipe (25 through 80mm). The
extended beryllium copper paddle, also included, is for larger
pipe sizes up to 6" (150mm). Paddle length conforms to ASTM
tee standards.
Materials
Body: Cast brass ASTM
Bellows: Brass ASTM B-36
Cover: Epoxy coated die cast zinc
Enclosure: Epoxy coated die cast zinc
Paddle: Beryllium Copper ASTM B-194
Coupling: Brass ASTM B-36
O-rings: Buna N
GENERAL
SIGNALING
EQUIPMENT
11S1
Watts product specifications in U.S. customary units and metric are approximate and are provided for reference only. For precise measurements,
please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials with-
out prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.
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