Paquin is spotlighting our P398 Thermal Flow Switch, a compact, robust thermal-dispersion switching for real-time flow monitoring. Built for pump protection, cooling systems, and leak monitoring across water, oils, gases, refrigerants, and hydraulics.
Built for industrial realities: 1,450 psi (100 bar) rating, IP65, rotatable housing, and configurable outputs (relay / NPN / PNP).
Technology: thermal dispersion / heat-transfer flow switching with fast start-up and simple potentiometer setpoint tuning.
Media coverage: water, oils, gases, refrigerants, hydraulic systems.
The Problem The P398 Solves
When flow drops below a safe threshold, especially in pump and cooling loops, equipment can overheat, run dry, or fail unexpectedly. The P398 Thermal Flow Switch provides a straightforward way to detect low/no-flow conditions and trigger alarms or interlocks, with a clear LED indication of flow status relative to the setpoint.
What’s New / Why It’s Different
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Wide setpoint coverage by medium
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Water: 0.03–5 ft/s (1–150 cm/s)
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Oil: 0.1–10 ft/s (3–300 cm/s)
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Gas: 0.65–65 ft/s (20–2000 cm/s)
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Output flexibility: choose Relay (NO+NC), NPN (NO+NC), or PNP (NO+NC).
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Operator-friendly visibility: LED logic shows whether flow is below / at / above the switch point; setup is potentiometer-based.
- Mechanical fit: ¼″ or ½″ NPT male and G ¼ / G ½ male, plus probe length options (13 mm default; up to 60 mm).
Applications
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Pump protection
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Cooling systems / cooling circuits
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Leak monitoring / flow assurance
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Water, gases, oils, hydraulics, refrigerants (and similar compatible media)
Key Specifications (snapshot)
| Parameter | Value |
|---|---|
| Principle | Thermal dispersion / heat transfer (flow switching) |
| Setpoint range (water) | 0.03 ... 5 ft/s |
| Setpoint range (oil) | 0.1 ... 10 ft/s |
| Setpoint range (gas) | 0.65 ... 65 ft/s |
| Output options | Relay (NO+NC) / NPN (NO+NC) / PNP (NO+NC) |
| Power | 18 .. 30 VDC |
| Pressure rating | 1,450 psi (100 bar) |
| Temperature Range (ambient & medium) | −4 to 176°F (−20 to 80°C) |
| Protection | IP65 |
| Connections | ¼″ / ½″ NPT male or G ¼ / G ½ male |
| Materials | Aluminum housing, stainless-steel probe |
| Display; start-up | LED stack: red/yellow/green flow status; 1–8 seconds |
Ordering & Availability
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Model: P398; select output, probe length, and process connection, M12 mating electrical connection assembly, and optional welding socket (see "Build Your Part Number").
Download the data sheet (for full technical parameters and dimensions of the P397)
Visit the product page & request a quote - our team will help you select your exact build.