Series-3000MR-3000MRS

Supported Applications

The Dwyer Series 3000MR and 3000MRS Photohelic® Switch/Gages combine a differential pressure gage with low/high set-points in a compact size. These units are designed for use with air and non-combustible, compatible gases, as well as non-corrosive gases. Documented applications include pneumatic conveying systems, air conditioning systems, and clean rooms.

Operating Conditions & Performance

The series operates within a process temperature range of 20 to 120°F (-6.67 to 48.9°C). Standard pressure ratings cover -20" Hg to 25 psig (-0.677 bar to 1.72 bar), with optional constructions available for higher pressures: the MP option increases the maximum rated pressure to 35 psig (2.41 bar) and the HP option to 80 psig (5.52 bar). Gage accuracy is specified as ±2% of full scale, with specific model variations noted at ±3% or ±4% of full scale depending on the range.

Process connections are provided via duplicated 1/8" female NPT ports located on the side and back. The unit weighs 1.8 lb (816 g) and features a 4" (101.6 mm) dial face with an overall height of 3-1/8" (79.38 mm). Mounting orientation requires the diaphragm to be in a vertical position; other orientations require consultation with the factory.

Configuration Options

The series offers extensive configuration options across measurement ranges, output types, and environmental protections:

• Measurement Ranges: Available scales include 0-0.25 in w.c., 0-100 in w.c., 0-60 Pascals to 0-4.0 kPa, and various mm w.c./cm w.c. ranges.
• Output Signals: Models are available with either electromechanical relays (3000MR) or solid-state technology (3000MRS). The 3000MR models feature Form C relay contacts rated for resistive loads of 1.0A @ 30 VDC, 0.3A @ 110 VDC, or 0.5A @ 125 VAC with gold over clad silver contacts suitable for dry circuits.
• Power Requirements: All models require a regulated 24 VDC power supply (±10%). The solid-state relay switching voltage is rated at 20-280 VAC (47 - 63 Hz).
• Housing and Bezel Options: A standard bezel is available, or the optional -SS suffix provides a 304 brushed stainless steel bezel that maintains backward compatibility with standard Magnehelic® gage installation diameters.
• Special Service Options: Configurations include the -LT option for use under 20°F (-6.7°C), the -WP weatherproof housing, and tamper-proof knobs requiring a spanner key (-TAMP).

Cable assemblies are standard at 18" (45 cm) or 18" (46 cm) depending on the model variant, with optional lengths available up to 100' (30.5 m). Wetted materials should be confirmed by consulting the factory.

Key Product Differences

The primary distinction between models lies in the switching technology and contact configuration:

• Series 3000MR (Electromechanical): Employs versatile electromechanical relays with gold over clad silver contacts. Each set point utilizes a Form C relay (SPDT). These units are noted for suitability in dry circuits.
• Series 3000MRS (Solid-State): Utilizes solid-state technology, providing SPST N.O. (Single Pole Single Throw, Normally Open) relays. This design supports high cycle rate applications without degradation and allows the gage reading to remain accurate even if power is interrupted.

Both series share identical physical dimensions for standard bezels and offer adjustable set points via external knobs on the face of the unit. The -SS stainless steel bezel option alters the overall height to 2-21/32" (67.5 mm) while maintaining a 4-3/4" (120.7 mm) O.D.