McDonnell & Miller 114400 FS4-3 General Purpose Liquid Flow Switch (1 Inch NPT, SPDT, 160 PSI)
McDonnell & Miller 114400 FS4-3 General Purpose Liquid Flow Switch (1 Inch NPT, SPDT, 160 PSI)
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| Performance Parameter | Engineering Baseline Value |
|---|---|
| Manufacturer Part Number (MPN) | 114400 |
| Model Designation | FS4-3 (General Purpose Series) |
| Process Connection Size | 1" NPT (Male Threaded) |
| Electrical Contact / Rating | SPDT Snap Switch (7.4A @ 120VAC / 3.7A @ 240VAC) |
| Maximum Operational Pressure | 160 PSI (11.3 kg/cm²) |
| Fluid Temperature Range | 32°F to 300°F (0°C to 149°C) |
| Included Stainless Paddles | 4 Paddles (1", 2", 3", & 6" Segmented) |
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Apply for Trade Account & Terms →McDonnell & Miller 114400 (Model FS4-3) General Purpose Liquid Flow Switch
Engineered for universal flow monitoring in commercial and industrial HVAC, hydronic, and process liquid piping networks, the McDonnell & Miller 114400 (Model FS4-3) is a heavy-duty paddle-style liquid flow switch. Featuring a standard 1" NPT male process connection and a single pole, double throw (SPDT) snap switch rated for 120/240VAC operation, this unit automatically signals pumps, burners, or alarms when liquid flow starts or stops.
The FS4-3 incorporates a sealed Monel bellows and hardened stainless steel bearings to eliminate internal friction and maximize service life in continuous-duty applications. It comes factory-equipped with four trimmed stainless steel paddles (1", 2", 3", and 6") to fit pipe sizes ranging from 1" up to 6" diameter, making it one of the most versatile flow switches on the market.
Key Performance & Construction Highlights:
- Universal Pipe Fitting: Supplied with 4 interchangeable stainless steel paddles to accommodate 1", 2", 3", and 6" nominal pipe sizes.
- Adjustable Switch Sensitivity: Features an accessible sensitivity adjusting screw for fine-tuning flow activation thresholds on-site.
- Sealed Monel Bellows Assembly: Isolates electrical snap components from fluid streams to ensure leak-free, corrosion-resistant operation.
- Dual Electrical Knockouts: Enclosure features electrical knockouts on both sides for quick wiring from either orientation.
⚠️ Application Profile: Ideal for water chillers, commercial boiler safety cut-offs, liquid heat exchange loops, water treatment systems, and pump proving circuits handling up to 160 PSI and fluid temperatures from 32°F to 300°F.
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