Description
The Xylem-McDonnell & Miller FS6-3/4 (Part Number 115400) is a high-sensitivity, in-line liquid flow switch engineered for dependable flow detection in hydronic heating, cooling, and process piping systems. Featuring a 3/4″ NPT connection and a snap-acting SPDT (Single-Pole, Double-Throw) switching mechanism, this unit provides precise, responsive flow sensing to protect pumps, boilers, and other critical hydronic equipment from dry-run or no-flow conditions.
Key Features
- 3/4″ NPT in-line pipe connection for straightforward installation
- High-sensitivity design detects low flow rates for maximum system protection
- Snap-acting SPDT switch for reliable, positive switching action
- Compact in-line form factor — no tee fittings or paddle extensions required
- Suitable for hydronic heating and cooling systems, boiler protection, and liquid process applications
- Durable construction built to withstand the demands of commercial and residential HVAC environments
- Part of the trusted McDonnell & Miller FS6 series, a recognized standard in flow switch technology
Application
The FS6-3/4 is ideal for use in hot water heating systems, chilled water systems, and general liquid piping where flow verification is required. It is commonly used to interlock pumps and boilers, ensuring equipment operates only when adequate liquid flow is present — preventing costly damage from overheating or dry operation.
Product Specifications
- Brand: Xylem-McDonnell & Miller
- Model: FS6-3/4
- Part Number: 115400
- Connection Size: 3/4″ NPT
- Installation Type: In-Line
- Switch Type: Snap-Acting SPDT (Single-Pole, Double-Throw)
- Sensitivity: High Sensitivity
- Series: FS6







Reviews
There are no reviews yet.