Series-A4

Supported Applications

The Dwyer Series A4 is a rugged differential pressure switch designed for service with compatible gases. The piston design enables mounting in any orientation and allows the unit to carry moderate shock and vibratory loads.

Operating Conditions & Performance

The series handles system pressures up to 6000 psig (413 bar) while measuring differential pressure ranges from 7-13 psid (.48-.89 bar) on the A4-1 model up to 120-250 psid (8.3-17.2 bar) on the A4-5 model. The maximum differential pressure limit is rated at 2000 psid (138 bar). Operating temperature limits are -65 to 225°F (-54 to 107°C).

Wetted materials consist of anodized aluminum for the body, piston, and fittings, with a steel spring. The switch type is SPDT.

Model Selection Performance

• A4-1: Repeatability ±2 psi (.14 bar); Set Point Increasing 7-13 psid (.48-.89 bar), Decreasing 2-7 psid (.14-.48).
• A4-2: Repeatability ±4 psi (.28 bar); Set Point Increasing 13-25 psid (.89-1.7 bar), Decreasing 5-16 psid (.34-1.1).
• A4-3: Repeatability ±8 psi (.55 bar); Set Point Increasing 25-45 psid (1.7-3.1 bar), Decreasing 10-21 psid (.68-1.5).
• A4-4: Repeatability ±16 psi (1.1 bar); Set Point Increasing 35-160 psid (2.4-11.0 bar), Decreasing 20-80 psid (1.4-5.5).
• A4-5: Repeatability ±32 psi (2.2 bar); Set Point Increasing 120-250 psid (8.3-17.2 bar), Decreasing 35-120 psid (2.4-8.3).

Configuration Options

The Series A4 offers field adjustments for set points within the documented ranges. The unit features a process connection of 1/4" female NPT and electrical connections via 24 AWG X 12" (30.5 cm) wire leads.

Electrical Ratings

• AC: 3 VA, 0.25A @ 120 VAC
• DC: 5 VA, 0.25A @ 175 VDC

The device carries CE agency approvals and weighs 8.5 oz (241 g). Overall dimensions are 3-3/4" (95.25) length, 1-1/2" (38.10) height, and 1-1/4" (31.75) width.

Key Product Differences

Variants within the series are distinguished by their model number suffixes (A4-1 through A4-5), which correspond to specific repeatability tolerances and set point adjustment ranges for increasing or decreasing pressure. The wiring color code is defined as WHITE for common, BLUE for N.C., and BLACK for N.O.