Description
Xylem-McDonnell & Miller FS1-J In-Line Liquid Flow Switch
The Xylem-McDonnell & Miller FS1-J is a high-sensitivity, in-line liquid flow switch engineered for dependable flow detection in hydronic heating, cooling, and fluid handling systems. Featuring a 1/2″ BSPT connection and a snap-acting SPDT (Single-Pole, Double-Throw) switching mechanism, the FS1-J delivers fast, precise response to changes in liquid flow — making it an essential safety and control device for a wide range of commercial and residential HVAC applications.
Key Features
- High-sensitivity paddle design detects low flow rates with accuracy
- Snap-acting SPDT switch provides reliable make/break switching action
- 1/2″ BSPT in-line pipe connection for straightforward installation
- Compact, in-line body design minimizes installation space requirements
- Suitable for use in hydronic heating and cooling systems, chilled water loops, and fluid process piping
- Durable construction for long service life in demanding HVAC environments
- Part Number: 113550
Typical Applications
- Hydronic boiler and chiller flow protection
- Pump proving and flow verification circuits
- Chilled water and hot water distribution systems
- Liquid cooling equipment protection
- Industrial fluid handling and process control
Why Choose the FS1-J?
McDonnell & Miller, a trusted Xylem brand, has been a leader in flow and level control for over a century. The FS1-J continues that legacy with a robust, field-proven design that protects equipment from dry-run or low-flow conditions. Its snap-acting SPDT output integrates easily with standard control panels, relays, and building automation systems, providing both safety shutdown and status monitoring capabilities.
