Series-A1PS-A1VS

Supported Applications

The Dwyer Series A1PS/A1VS Economical Pressure Switch is designed for the direct control of pumps and motors. These switches monitor pressure, vacuum, or compound ranges in systems handling compatible liquids or gases.

Operating Conditions & Performance

The series utilizes a diaphragm sensor element with wetted materials consisting of Buna-N (diaphragm) and zinc alloy with chromate finish (body with fitting). The switches operate within an ambient temperature range of -31 to 185°F (-35 to 85°C).

Performance specifications vary by model:

• A1PS-14: Set point range 1.5 to 3.5 psi (10 to 24 kPa); repeatability ±0.15 psi (1 kPa).
• A1PS-24: Set point range 3 to 40 psi (21 to 276 kPa); repeatability ±1.0 psi (7 kPa).
• A1PS-34: Set point range 30 to 150 psi (207 to 1034 kPa); repeatability ±5.0 psi (34 kPa).
• A1PS-44: Set point range 100 to 500 psi (689 to 3445 kPa); repeatability ±20.0 psi (138 kPa).
• A1VS-14: Vacuum set point range 6-28" Hg (-20 to -94 kPa); repeatability ±1.2" Hg (-4 kPa).
• A1VS-24: Compound set point range 28" Hg to 3.5 psig (-94 to 24 kPa); repeatability ±1.2" Hg (-4), ±0.15 psi (1).

The maximum pressure limit is rated at 600 psig, and vacuum limits are specified as 29.9" Hg for vacuum and compound models only.

Electrical Ratings & Switching Characteristics

• Switch Type: SPDT snap action with field-adjustable set point via knurled screw cap.
• Load Capacity: 15 A (resistive) @ 250 VAC, 1/2 HP @ 250 VAC.
• Cycling Rate: Not to exceed 1 Hz. For applications exceeding 20 cycles per minute, consult Dwyer Instruments Inc.

Mechanical Dimensions & Connections

• Process Connection: 1/4" male NPT.
• Electrical Connection: Three screw terminals (Common, Normally Open, Normally Closed) with a Ground Screw (green).
• Housing Dimensions: Height: 3.625 in [92.08 mm]; Width: 2.375 in [60.33 mm]; Depth: 0.625 in [41.28 mm].
• Weight: 7.4 oz (209 g).

Configuration Options

The series offers configurable set point ranges across pressure, vacuum, and compound applications to accommodate specific process requirements.

• A1PS Models: Available in four distinct pressure ranges (A1PS-14 through A1PS-44) covering 1.5 psi up to 500 psi.
• A1VS Models: Offered for vacuum and compound service, including a dedicated vacuum range (6-28" Hg) and a compound range spanning from full vacuum to positive pressure (-94 kPa to 24 kPa).

All models feature an adjustable set point aligned with the top of the self-locking adjusting nut against an adjacent range scale. The switches can be mounted in any position.

Approvals & Compliance

• Certification: UL listed.

Note: Customer media and environment must be compatible with the construction materials as outlined in general specifications. The instrument must not be subjected to temperatures, pressure, or electrical loads exceeding those appearing on the name plate or published literature.

Key Product Differences

The primary distinction between models lies in their measurement range and service type:

• A1PS Series (Pressure): Designed for positive pressure applications. Models A1PS-14, A1PS-24, A1PS-34, and A1PS-44 correspond to increasing set point ranges with corresponding increases in repeatability tolerance.
• A1VS Series (Vacuum/Compound): Designed for negative pressure or combined vacuum/pressure applications. Model A1VS-14 covers pure vacuum service, while A1VS-24 provides a compound range crossing zero from 28" Hg to 3.5 psig.

All variants share identical housing dimensions, electrical ratings (15A SPDT), process connection type (1/4" male NPT), and wetted material composition.