McDonnell & Miller FS5-J-1 Flow Switch

The McDonnell & Miller FS5-J-1 (Part Number 114785) is a high-reliability, in-line liquid flow switch specifically engineered for general-purpose applications where low-flow sensitivity is required. Built with a 1" BSPT (British Standard Pipe Taper) connection, this unit facilitates direct integration into international piping systems without the need for additional pipe tees, reducing potential leak points and installation time. The internal mechanism features a snap-acting SPDT switch, providing definitive electrical making or breaking of circuits for boiler pump control, cooling systems, and industrial process monitoring.

Designed for durability in demanding mechanical rooms, the FS5-J-1 flow switch utilizes a brass body and EPDM elastomer components, supporting a maximum operating pressure of 150 psi (10.5 kg/cm²). Technicians can easily fine-tune the device's response via the external sensitivity adjusting screw, allowing for precise field calibration based on specific system flow requirements. This model operates effectively in liquid temperatures up to 250°F (121°C) and is housed in a NEMA Type 1 enclosure, ensuring protection for the electrical contacts in standard indoor environments.

• In-line configuration allows for a compact footprint by eliminating the requirement for a separate pipe tee.
• BSPT connection threads ensure compatibility with equipment requiring international threading standards.
• Snap-acting SPDT contacts provide reliable low-flow sensitivity and prevent chattering in HVACR systems.
• Adjustable flow rate settings via an accessible screw allow for field modification to match pump flow velocities.
• Rugged brass construction and EPDM seals provide long-term performance in water-based heating and cooling loops.

• Can this flow switch be used in vertical piping? To ensure accurate sensing and avoid paddle damage, the FS5-J-1 must be installed in a horizontal pipe run with at least five pipe diameters of straight run on each side.
• Is the FS5-J-1 compatible with glycol systems? Yes, the brass and EPDM wetted parts are suitable for water and standard glycol solutions typically found in hydronic systems.
• What is the maximum flow velocity for this unit? For reliable operation and to prevent internal component fatigue, system velocity should not exceed 10 feet per second.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.