FSW-25 Trim to Size Paddle Type Flow Switch

Supported Applications

The Omega FSW-25 Series is a trim-to-size paddle type liquid flow switch designed to detect the presence of fluid in piping systems. The unit operates by sensing the force of moving liquid, which displaces an adjustable paddle against a spring return mechanism. This mechanical action actuates an internal reed switch (normally open) when flow occurs and returns it to the no-flow condition during static or zero-flow states.

Documented applications include monitoring liquid flow in metal pipes using 1" trim sizes, with specific guidance that plastic pipe installations require a minimum size of 1¼". The series is not designed for use in human applications.

Operating Conditions & Performance

The FSW-25 Series operates within a process temperature range of -30 to 150°C (30 to 300°F). It features an enclosure rating of NEMA4 (IP65) and is constructed with an aluminum alloy housing. The pressure rating for the series is 355 psig.

Performance characteristics include a repeatability of ± 5%. The switch actuates when flow raises the paddle at an upward angle of 20 to 30 degrees or more, closing the circuit via magnet movement. Maximum fluid viscosity supported is 200 SSU or 43 centistokes.

Standard Actuation and De-Actuation Flow Rates (GPM Water) vary by pipe line size and paddle length:

• 1" Pipe Line Size: With a 1" paddle, actuation occurs at approximately 5 GPM with de-actuation at 4 GPM.
• 1¼" Pipe Line Size: A 1¼" paddle provides actuation at 6.5 GPM and de-actuation at 4.5 GPM; a 2½" paddle yields actuation at 23 GPM and de-actuation at 20 GPM.
• 1½" Pipe Line Size: A 1½" paddle provides actuation at 9 GPM and de-actuation at 7 GPM; a 2" paddle yields actuation at 15 GPM and de-actuation at 12 GPM.
• 2" Pipe Line Size: A 2" paddle provides actuation at 14 GPM and de-actuation at 10 GPM; a 3" paddle yields actuation at 27 GPM and de-actuation at 22 GPM.
• 2½" Pipe Line Size: A 2½" paddle provides actuation at 18 GPM and de-actuation at 12 GPM; a 3" paddle yields actuation at 33 GPM and de-actuation at 27 GPM.
• 3" Pipe Line Size: A 3" paddle provides actuation at 20 GPM and de-actuation at 13 GPM; a larger configuration yields actuation at 24 GPM and de-actuation at 17 GPM.

Configuration Options

The series offers configurable process connections to accommodate different piping standards. The primary variants include:

• FSW-25: Paddle flow switch with head and 1" PT threads.
• FSW-25-NPT: Paddle flow switch with head and 1 NPT threads.

The paddle length is adjustable to match the diameter of the pipe, allowing for customization across various line sizes. Wetted materials include SUS304 (Similar to 304 SS). The series supports optional accessories including an audible alarm (70A-1) and a 10 Amp solid state relay (SSRL240AC10).

Key Product Differences

The primary distinction within the FSW-25 Series lies in the thread type of the process connection. The standard model utilizes 1" PT threads, while the NPT variant provides compatibility with National Pipe Taper connections.

Installation requirements differ based on pipe material: the 1" trim size is restricted to metal pipes only, whereas plastic pipe applications require a minimum line size of 1¼". The unit includes an operator's manual and requires sealing at electrical entry points to prevent moisture ingress during installation.