McDonnell & Miller 305200 Replacement Switch

The McDonnell & Miller 305200 Replacement Switch (Model number FS4-33) is a high-performance SPDT (Single Pole, Double Throw) snap-action assembly specifically engineered for integration with general purpose liquid flow switches. This technician-grade component serves as the core electrical interface for Series FS4-3 and FS4-3T units, detecting flow velocity changes to trigger or terminate power to downstream equipment such as pumps, burners, and auxiliary alarms. Designed for industrial and commercial hydronic systems, the FS4-33 switch provides reliable mechanical switching with 7.4 FLA at 120 VAC and 3.7 FLA at 240 VAC ratings, ensuring consistent performance in demanding environments. Note that while this unit fits the majority of the FS4-3 line, it is not compatible with D Series models. When performing a field replacement, ensure the sensitivity adjusting screw is calibrated to the specific flow requirements of the application to prevent short-cycling or delayed response times.

• Broad Compatibility: Direct OEM replacement for McDonnell & Miller FS4-3 and FS4-3T models, excluding the FS4-3D variants.
• Precision Engineering: Features a robust snap-action mechanism designed for 125 VA pilot duty, facilitating accurate circuit making and breaking.
• Ease of Installation: Includes a standardized mounting bracket and color-coded terminal wires for efficient integration into existing enclosures.
• Reliable Performance: Capable of managing locked rotor amps (LRA) up to 44.4 at 120 VAC, maintaining circuit integrity under heavy startup loads.

Is the 305200 switch compatible with the FS4-3D Series?
No, the 305200 (Model FS4-33) is and intended for all FS4-3 models except the D Series. For those units, a specific FS4-3D replacement switch is required due to different terminal configurations.

Can I use this switch for both NO and NC applications?
Yes, as a Single Pole, Double Throw (SPDT) switch, the 305200 can be wired for either normally open (NO) or normally closed (NC) operation, or both, depending on your system's wiring requirements.

What are the electrical ratings for this replacement part?
This switch is rated for 7.4 Full Load Amps (FLA) and 44.4 Locked Rotor Amps (LRA) at 120 VAC, or 3.7 FLA and 22.2 LRA at 240 VAC, making it suitable for a wide range of pilot duty and motor applications.

This item is not eligible for free shipping.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.