Valves-Connectors

Supported Applications

The Dwyer Nylon Valves & Connectors series provides accessories for permanent installation in instrument systems, specifically designed to interface with A-316 and A-317 manometer connections, type C manometers, and Magnehelic® gages. These components facilitate pressure monitoring, system connectivity, and gage protection by connecting instruments to metal tubing or 1/8" pipe.

Documented applications include:

• Venting gauges to atmosphere via the A-310A/A-310B 3-way vent valves
• Shutting off pressure sources using brass shut-off valves (models A-311, A-312)
• Monitoring multiple pressures with a single gage through porting and dual-porting configurations (models A-355, A-365)
• Protecting Magnehelic® or Photohelic® gages against overpressure from regulator failure using the A-321 safety relief valve

Operating Conditions & Performance

The series encompasses a range of pressure ratings and material constructions tailored to specific connection types. Pressure limits vary by model, with plastic vent valves rated for 80 psi (A-310A) or 10 psi (A-310B), while PVC tees support up to 125 psi maximum.

Materials include plastic, brass, PVC, acrylic, nylon, and rubber. The A-321 safety relief valve is designed to open at 10 psi. Specific operating temperature ranges are not provided in the source documentation for these accessories; selection should be based on the material compatibility of the specific model (e.g., acrylic, plastic, brass) with the process media.

Key Pressure Ratings by Model

• A-310A: 80 psi rating
• A-310B: 10 psi rating
• A-5003-5 / A-5004-4: 125 psi maximum

Configuration Options

The series offers configurable options for venting, isolation, port switching, and safety relief. Variants differ by function (vent valve vs. shut-off), material composition, connection geometry, and pressure capacity.

• Vent Valves: 3-way plastic valves with positions for Line, Off, and Vent; available in 1/8" NPT to 1/4" metal tubing configurations (A-310A/A-310B).
• Shut-off Valves: Brass models connecting 1/8" NPT to either 1/8" NPT or 1/4" metal tubing; includes shut-off type gage connectors for rubber tubing (A-315) and PVC tees with multiple female/male NPT ports.
• Porting Valves: Acrylic plastic valves allowing indication of pressure at two points (A-355) or monitoring three pressures, two at a time (A-365), using 1/8" NPT inserts/fittings.
• Gage Connectors: Bushing types for 1/8" pipe thread openings; slip-fit connectors for 250 series A.F. gages with reduced OD threads or compression fittings (A-316, A-317, A-322); flexible PVC tubing adapters (A-319).
• Safety Relief: Brass valve opening at 10 psi for D.P. applications, mounting in tee fittings or unused gage ports with a reducer.

Key Product Differences

Variants within the series are distinguished by their specific mechanical function and connection interface rather than electronic output types. The A-310A replaces former brass model A310 but is constructed of plastic, whereas models A-311 and A-312 remain brass shut-off valves with differing outlet connections (NPT vs. metal tubing).

Porting capabilities vary by the number of pressures monitored: Model A-355 supports two points with a single gage, while model A-365 enables monitoring three pressures simultaneously in pairs. Gage connectors differ in thread type and fitment style; for example, A-317 features less OD threading specifically for slip-fit installation into 3/4" diameter openings on 250 series A.F. gages.

Some models carry a California Proposition 65 warning regarding exposure to chemicals including Lead.