McDonnell & Miller FS4-3 Switch 30067439-890 Key Benefits Versatile SPDT Logic:

Key Benefits Versatile SPDT Logic: Seamlessly switches between two branch lines or selects between dual input signals for complex pneumatic sequencing

Commercial Grade: Built to handle the high-cycle demands of commercial-line heaters and hydronic boilers

Combustion Safety: Critical for preventing fuel leaks and ensuring proper manifold pressure regulation for safe indoor operation

Adjustable Performance: Includes six color-coded springs to field-select the desired operating span and 3 to 13 psi control ranges

Demineralized or distilled water with high specific resistance may require specialized high-sensitivity controls or chemical treatment to ensure the circuit completes reliably

McDonnell & Miller FS4-3 Switch 30067439-890 Key Benefits Versatile SPDT Logic:For contractors requiring reliable system protection, the McDonnell & Miller FS4 3 (Part Number 114400) is a heavy duty general purpose liquid flow switch designed to monitor flow in heating, cooling, and water process lines. This 1" NPT unit features a single pole, double throw (SPDT) configuration, allowing you to easily integrate signal lights, alarms, motors, or burners into the control circuit. Engineered to operate at a max pressure of 160 PSI