Series-P3

Supported Applications

The Dwyer Series P3 Polypropylene Flow Switches are designed for monitoring fluid flow in piping systems using compatible liquids. Documented applications include pure water equipment, filter life monitoring, heat exchangers, and cooling systems.

• Pure water equipment
• Filter life monitoring
• Heat exchangers
• Cooling systems

Operating Conditions & Performance

The series operates within a process temperature range of 0 to 212°F (-18 to 100°C). Pressure limits are rated at 125 psig (8.6 bar) @ 70°F (21°C) and 50 psig (3.4 bar) @ 212°F (100°C). Set point accuracy is specified as ±20% of set point, with a repeatability of ±1%. The switches require filtration of 100 microns or better to ensure proper operation.

Set points are calibrated for vertical mounting with the inlet port down; some variation in actuation may occur in other orientations. Ambient temperature changes can affect switch set points due to variations in liquid specific gravity.

Configuration Options

The Series P3 offers fixed flow actuation set points ranging from 0.25 GPM (.95 LPM) to 2.0 GPM (7.57 LPM). The switches feature a hermetically sealed SPST, NO magnetic reed switch with an electrical rating of .08 A @ 120 VAC and are terminated via 24" (60.96 cm), polymeric wire leads, 22 AWG.

Process Connections

• 3/8" male NPT ports
• 1/4" quick disconnect adapters (requiring separate adapter selection)

Wetted Materials

The construction utilizes hydrolytically stable glass-reinforced polypropylene for the housing and end fittings. Internal wetted components include a PPS composite piston, 316 stainless steel spring, and fluorocarbon O-rings.

Key Product Differences

Variants are distinguished by connection type and fixed actuation set point:

• P3-3x Series (NPT): Models P3-31 through P3-35 feature 3/8" NPT connections with set points of 0.25, 0.50, 1.0, 1.5, and 2.0 GPM respectively.
• P3-4x Series (Quick Disconnect): Models P3-41 through P3-45 feature quick disconnect connections with identical set points of 0.25 to 2.0 GPM. These models require an adapter for installation, such as the P3-801 series or shut-off valve variants.

The overall length is approximately 4" (102 mm) for NPT ports and 4.22" (107 mm) for quick disconnect configurations. The unit weight is listed at 5 oz (0.14 kg).