McDonnell & Miller 120601 FS8-W Liquid Flow SwitchMcDonnell & Miller 120601 FS8-W Liquid Flow Switch
McDonnell & Miller 120601 FS8-W Liquid Flow Switch
McDonnell & MillerSKU: 38339

McDonnell & Miller 120601 FS8-W Liquid Flow Switch

$402.00
In stock (21)

The McDonnell & Miller 120601 FS8-W is a general-purpose NEMA 4X liquid flow switch for hydronic heating, cooling, and industrial flow alarm and control circuit applications. Paddle-type sensing element with sealed Monel bellows provides reliable actuation across a broad range of pipe sizes and flow conditions. Single pole, double throw (SPDT) snap switch; 1 in. NPT connection; 160 psi maximum operating pressure; 32–225°F operating range. Rated 7.4A at 120 VAC / 3.7A at 240 VAC, 50/60 Hz.

Four stainless steel paddles included (1 in., 2 in., 3 in., and 6 in.) to fit a range of pipe sizes; the extended paddle can be trimmed to fit intermediate sizes. Sensitivity adjusting screw allows field calibration of actuation flow rate. Direct replacement for NEMA 4X-style flow switches from Potter/Taco, Watts, Penn, and other manufacturers. Not intended for use in potable water applications. Requires professional installation by a licensed HVAC or plumbing technician.

Shipping policy

Orders placed by 2:00pm EST will ship same day, except on holidays.

More Details

Product overview
  • NEMA 4X enclosure — watertight and dust-tight; suitable for applications with environmental exposure
  • SPDT snap switch — 7.4A at 120 VAC / 3.7A at 240 VAC; 125 VA; 50/60 Hz
  • Sealed Monel bellows for corrosion-resistant, reliable flow actuation
  • Four stainless steel paddles included — 1 in., 2 in., 3 in., and 6 in. (25, 50, 80, and 150mm); extended paddle can be trimmed to fit intermediate pipe sizes
  • Sensitivity adjusting screw for easy field calibration of actuation flow rate
  • 1 in. NPT connection; maximum operating pressure: 160 psi (11.3 kg/cm²)
  • Operating range: 32–225°F; maximum operating velocity: 10 fps
  • Direct replacement for NEMA 4X-style flow switches from Potter/Taco, Watts, Penn, and other manufacturers
  • UL Listed; CSA Certified
  • Not intended for potable water applications
  • Professional installation required
Specifications
Manufacturer Part Number 120601
UPC 751875000939
Overall Dimensions 2-3/4 in H
Material n/a
Domestic or Import n/a
End Style n/a
Type n/a
ADA Compliance n/a
Warning Professional installation required
Standards and Approvals CSA Certified | UL Listed
Resources
Delivery & Returns

Orders will ship same day if received by 2pm EST.

Upcoming holiday closures: July 3, 2026

All returns are inspected on receipt; credit is issued after condition is confirmed. Credit is issued only for items returned in original, saleable condition after inspection.

FINAL SALE ITEMS ARE NOT ELIGIBLE FOR RETURNS OR EXCHANGES.

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