Description
The Xylem-McDonnell & Miller FS-1 (Part Number 113200) is a high-sensitivity, in-line liquid flow switch engineered for reliable flow detection in hydronic heating, cooling, and water-based HVAC systems. Featuring a 1/2″ NPT in-line connection and a snap-acting SPDT (Single-Pole, Double-Throw) switch mechanism, the FS-1 delivers precise, repeatable switching action to protect pumps, boilers, and other hydronic equipment from low-flow or no-flow conditions.
McDonnell & Miller — a trusted Xylem brand — has long been the industry standard for hydronic controls and flow sensing. The FS-1 is built to perform in demanding commercial and residential applications where accurate flow verification is critical to system safety and efficiency.
Key Features
- High-sensitivity design detects low flow rates for maximum system protection
- Snap-acting SPDT switch provides reliable, positive switching action
- 1/2″ NPT in-line connection for straightforward installation in existing pipework
- Compact in-line body minimizes installation space requirements
- Suitable for hydronic heating and cooling systems, boiler protection, and chiller applications
- Trusted Xylem-McDonnell & Miller quality and engineering
Specifications
- Brand: Xylem-McDonnell & Miller
- Model: FS-1
- Part Number: 113200
- Connection Size: 1/2″ NPT
- Installation Type: In-Line
- Switch Type: Snap-Acting SPDT (Single-Pole, Double-Throw)
- Sensitivity: High Sensitivity
- Media: Liquid
Typical Applications
- Hydronic heating and cooling system flow verification
- Boiler low-water and low-flow protection
- Chiller and heat pump flow interlock circuits
- Pump protection and flow proving
- Commercial and residential HVAC hydronic systems
